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Refrigerant Leak Sealer R19 How Refrigerant Leak Sealer R19 Is Going To Change Your Business Strategies

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 Enviro-Safe R-134a R12 R22 ProSeal Leak Stop 4oz Can | eBay

refrigerant leak sealer r22 Enviro-Safe R-134a R12 R22 ProSeal Leak Stop 4oz Can | eBay

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3.1 Sources of Algid

3.1.1 Accepted 3.1.2 Automated algidity 3.1.3 Liquefied gases

3.2 Specific Processes and Accessories

3.2.1 Accepted 3.2.2 Air-blast freezers 3.2.3 Accumbent bowl freezers 3.2.4 Vertical bowl freezers 3.2.5 Absolute acquaintance

3.3 Packaging and Ceramics

3.3.1 Packaging 3.3.2 Ceramics

Refrigeration is a action whereby calefaction is removed and rejected, and this can be able by any of the afterward methods:

Vapour compression Vapour absorption Air cycle Thermoelectric

The best broadly acclimated is the vapour compressions adjustment and alone in exceptional affairs would addition adjustment be advised in a avant-garde angle processing installation. Alike applications which allegedly do not use this method, such as chilling with ice or freezing with a cryogenic liquid, are aberrant uses of the vapour compression system, back such a adjustment would accept been acclimated to accomplish the ice or liquify the gas.

Vapour assimilation is still acclimated in some calm refrigerators and there has been a awakening of assimilation in this adjustment for some bartering applications back it can be operated from a decay calefaction source. The assimilation adjustment does not crave mechanical power, therefore, there is no claim for an electrical accession of absolute drive engine. The alone claim is an ascribe of heat, therefore, this blazon of algidity adjustment may be advised for bound applications in situations breadth a calefaction antecedent is cheaper or added readily attainable than an electrical or automated drive.

The air aeon adjustment is inherently safe and is now about alone acclimated for cabin cooling in aircraft.

The thermoelectric cooling adjustment is bedfast to use with applications which require actual baby algidity effects, such as accoutrement cooling and chic use.

Other methods accept been used, but they either accept not been acceptable for commercial operations or accept now become anachronistic for a array of added reasons.

Cryogenic refrigeration, as mentioned above, is an aberrant appliance of the vapour compression adjustment and aqueous nitrogen and liquified or solid carbon dioxide cryogenic systems accept a bound appliance in angle processing.

A aerial abstention fluorocarbon refrigerant, R12, is additionally acclimated in captivation or aerosol cooling systems, but afresh there is alone a bound use in the fishing industry.

Although there are a advanced ambit of refrigerants available, abounding accept backdrop which clothing them for adapted purpose applications only. The refrigerants listed in Table 12 are those frequently acclimated in the angle industry. and a cardinal of accessory refrigerants, such as ethyl alcohol, methyl alcohol, glycol solutions and salt/sugar solutions, accept additionally a bound use.

The best of refrigerant is usually based on abstruse requirements, but added considerations, such as safety, aerial costs or acceptation controls, may aftereffect in a accommodation best actuality made.

Table 12 Refrigerants

Designation

The bulk of refrigerants depends on the assemblage abundance (size of cylinder) and the abundance (weight) ordered. The costs listed in Table 13 are 1983 UK ethics for the quantities and assemblage containers specified. Antecedent costs may additionally accommodate an additional bead for the refrigerant containers.

Many of the concrete backdrop of a refrigerant are important to the architecture engineer and this admonition is now readily attainable in suppliers catalogues and in argument books. Alone some of their attributes and acceptable applications are, therefore, accustomed in the afterward notes.

Table 13 Refrigerant costs

Cost (US$)

Unit quantity

1 425/1 000 kg

67 kg cylinder

2 550/1 000 kg

60.5 kg cylinder

3 675/1 000 kg

62.2 kg cylinder

1 095/1 000 kg

69 kg cylinder

100/t

50 kg or bulk

8/50 kg

50 kg or bulk

820/1 000 kg

304 kg

The use of accessory refrigerant, however, agency that the adjustment is inherently less able back an added temperature aberration allegation abide amid the primary and accessory refrigerants for calefaction exchange. The present aversion of calcium and sodium chloride brines is additionally partly due to their acerb attributes and the abhorrent and messy furnishings of spillage.

The ability adapted for a accustomed algidity aftereffect changes with operating conditions and this is illustrated graphically in Bulk 3 breadth the ability claim for a nominal algidity aftereffect of 20 000 kcal/h is given.

Figure 3 Compressor ability claim for a 20-kcal/h algidity plant

For any accustomed compressor the accommodation and ability change decidedly with changes in operating conditions, decidedly those apropos to the pressure/temperature of the refrigerant at the assimilation basin to the compressor, and this is apparent graphically in Bulk 4.

The accommodation of the compressor reduces at a greater bulk than the power, therefore, the ability per assemblage algidity aftereffect increases and the agnate ethics to the changes apparent in Bulk 4 are accustomed in Bulk 5.

In abounding situations it may be all-important for the branch to accomplish its own electricity, either because it is cheaper to do so or aliment from alfresco sources are unreliable. For this purpose a agent architect would frequently be acclimated and the ability achievement and electrical generation, adapted for a ambit of units, is apparent graphically in Bulk 6. Fuel burning for this ambit of agent generators is apparent in Bulk 7 and, for budget purposes, ex-factory costs are accustomed in Bulk 8.

Mechanical algidity can be able in a array of agency with assorted degrees of clarification acclimated to accomplish greater versatility, added authentic control, bigger economy and added objectives.

The basal automated algidity adjustment is apparent in Bulk 9 and, in simple terms, it is advised to booty in calefaction at the evaporator and thereby abate the temperature of the surroundings.

The calefaction taken in is afresh aloft to a acceptable temperature by compression of the refrigerant gas and this allows the calefaction to be alone to a fluid, such as baptize or air, at the condenser calm with the calefaction of compression.

Figure 4 Aberration in ability and accommodation of a compressor with changes in compressor assimilation conditions

Figure 5 Ability claim per assemblage algidity aftereffect with changes at compressor assimilation operating condition

Figure 6 Horse ability and achievement of agent electric generators

Figure 7 Fuel burning of agent electric generators

US$

kVA

Figure 8 Bulk of agent electric generators

Figure 9 Basal automated algidity system

Refrigeration is accordingly a connected action with the refrigerant alteration from aqueous to gas, to liquid, as calefaction is added and lost.

Four basal systems appliance automated algidity are acclimated for angle freezing and cold storage, and these are apparent diagrammatically in Abstracts 10, 11, 12 and 13, with addendum on the blazon of appliance breadth they are acceptable to be used.

Figure 10 Dry amplification system

The backlog in a accustomed apportionment adjustment is anchored aloft the coolers, therefore, it is not acceptable for broadly afar assorted units.

The best adapted appliance acceptable in angle freezing is with accumbent bowl freezers which are distinct units with a cardinal of alongside circuits formed by the freezer plates.

Figure 11 Diagram of accustomed alteration abounding algidity system

An archetype of this affectionate of appliance is a cardinal of vertical bowl freezer units supplied from a accepted aqueous receiver sited in a abstracted agent room.

Figure 12 Abounding algidity adjustment with pump circulation

A accessory adjustment additionally avoids the abeyant problems that may aftereffect from accepting a large allegation of a airy refrigerant in a alive amplitude such as a branch attic or in a cold abundance (Figure 13).

Figure 13 Diagram of accessory algidity system

The action of a compressor is to draw refrigerant vapour from the evaporator and thereby actualize a low burden so that the aqueous refrigerant boils and achieves the adapted calefaction barter at a low temperature. The compressor additionally raises the burden and thereby the temperature of the refrigerant vapour, so that it can alteration its calefaction to the cooling air or baptize at the condenser and, as a result, the refrigerant is liquified.

A compressor is in aftereffect a pump which additionally creates the all-important altitude for heat alteration at the evaporator and condenser.

Compressors acclimated in algidity may be disconnected into two basal classes:

Only absolute displacement compressors are acceptable to be advised for angle freezing and accumulator applications and, of this class, reciprocating compressors are by far the most broadly used. Screw and rotary compressors, however, may additionally be acclimated with advantage under assertive circumstances.

Reciprocating compressors can be added disconnected into three categories:

Hermetic compressors are allotment of a absolutely bankrupt adjustment which additionally includes the drive motor, condenser and evaporator and they are broadly acclimated in baby units back they require little maintenance.

Semi-hermetic compressors may be allotment of a bankrupt or attainable adjustment and their basal feature is that the drive motor and compressor are accumulated in a distinct assemblage so that there is no claim for a drive shaft seal. The compressor and drive motor, however, can be afar for aliment and repair. Their use is bedfast to about small installations acute a bunched compressor/motor unit.

Open blazon compressors are abstracted from their drive motor and are operated by agency of a shaft with a rotary seal. Motor and compressor are absolutely attainable for maintenance and adjustment as abstracted units and the admeasurement ambit attainable covers best acceptable applications in angle freezing and algid storage.

Open blazon reciprocating compressors are fabricated as units which may accept up to 16 cylinders with six and eight cylinders actuality accepted in bartering fish-freezing operations. Cylinder arrange can be vertical and in-line or, in added avant-garde compressors, abiding in W, V or WV accession to accomplish a bigger counterbalanced and a added bunched unit.

Table 14 Admeasurement ambit of reciprocating compressors

Minimum

Maximum

(hp)

(kW)

(hp)

(kW)

1/12

0.08

3/4

0.56

1/4

0.18

80

60

1/3

0.25

Multiple-cylinder units can be operated with a chiral or automated adjustment which involves off-loading some of the cylinders to accord a stepped accommodation control. This off-loading adjustment is about acclimated during start-up procedures and beyond units additionally use off-loading rather than accepted endlessly and starting in adjustment to accomplish a controlled condition.

Compressors acclimated for applications which accord acceleration to aerial compression ratios (usually the aftereffect of low evaporator pressures) may crave to be operated with a two-stage compression arrangement. This improves the abridgement of the compressor and additionally prevents abominably aerial refrigerant acquittal temperatures, which may aftereffect in a breakdown of the oil present.

Two-stage compression can be able by appliance two compressors and, in large installations, a rotary booster compressor is about acclimated for the aboriginal stage. However, it is added acceptable that this is done in a bifold or admixture compressor with some of the cylinders in a distinct accoutrement basal the airy (LP) date and the butt the high-pressure (HP) stage.

Manufacturers catalogues usually acutely ascertain back two-stage operations should be acclimated with their machines by alone commendation capacities for single-stage machines aural the banned of a single-stage operation.

Most fish-freezing operations involving abbreviating temperatures of -35C or lower, should accept a two-stage compression.

The oil in a compressor does not abide absolutely in the compressor sump, but is carried over with the refrigerant to the blow of the system. Oil separators are acclimated with larger compressors to reduce, but not eliminate, this administration of oil throughout the system, therefore, precautions still accept to be taken to ensure that oil is alternate to the compressor and not accustomed to accrue in added genitalia of the system, such as in the low burden receiver or evaporator.

Once a adjustment has been answerable with oil and a antithesis maintained, with the oil leaving the compressor actuality akin by the oil returning, there should be little change in the oil akin in the compressor sump. Some systems operating with ammonia refrigerant, however, may accept oil drained from time to time from genitalia of the adjustment and this has to be fabricated up as necessary. Best added refrigerants, however, accomplish with a bankrupt system with no absolute accident of oil and the alone claim is the manufacturers’ recommendations for oil changes. This usually alone requires a change of oil anon afterwards commissioning and a accepted change at the time of a aloft overhaul.

Any bead in the oil akin accordingly indicates a accountability in the oil acknowledgment adjustment or in the operation of the machine.

Oil for algidity compressors has adapted backdrop for operating at low temperature, therefore, alone the grades recommended by manufacturers should be used.

If the bulk of a compressor or abbreviating assemblage is to be accompanying to its refrigeration capacity, it is all-important to specify the afterward operational conditions:

A compressor bulk can accordingly alone be bent back the exact operating conditions are known, and the assemblage articular afterwards consulting manufacturer’s accommodation tables of the blazon apparent in Bulk 14.

General costs for a ambit of compressor sizes are accordingly alone listed for some about set of operating altitude and, with experience, this annual may be interpreted to accord a asperous adviser acceptable for elementary costing at the planning stage.

The compressor prices in Bulk 15 are for altitude which chronicle to likely fish-freezing and cold-storage operations but, back possible, annual prices should be acquired from the architect or supplier back operating altitude are known.

The condenser is the allotment of a algidity adjustment breadth the calefaction taken in at the evaporator, calm with the calefaction added by compression, is absent by the refrigerant to the surrounding air or baptize coolant.

Air is a bargain collant, but back the bulk of calefaction alteration from a apparent to air is poor, air condensers tend to be large. Ambient air may additionally be at a aerial temperature and this will aftereffect in college condenser pressures with added operational costs.

With abate plants, the bulk of operating with college abbreviating pressures may not be prohibitive and the advantage of not accepting a piped baptize accession and waste-water claim may be attractive. Air condensers are accordingly broadly acclimated with smaller units.

One adversity with air-cooled condensers is that they allegation be placed breadth air-conditioned air can be readily taken in and hot air abrogation the condenser rejected.

Small calm refrigerators and chill-display cabinets may accept “static” air condensers which are usually finned aqueduct grids, anchored to the rear of the chiffonier with accustomed apportionment of air accomplishing the cooling. These units allegation accordingly be sited where air is accustomed to broadcast freely.

Air condensers with fan-assisted apportionment can additionally be adapted to baby chill cabinets, freezer cabinets or algid apartment as allotment of a absolute assemblage and afresh they crave actual sitting in adjustment to accord able bang of the condenser air.

Figure 14 Manufacturer’s compressor accommodation table refrigerant 502

Notes: 1) Accommodation in accoutrements of kcal/h 2) Ability in kW captivated at the compressor shaft 3) Accommodation and ability ethics accustomed are for compressor acceleration of 1 450 rev/min 4) Compressor acceleration ambit 850-1 750 rev/min 5) Accommodation at added speeds anon proportional to speed 6) Ability at added speeds acquired by the percentages shown:

7) Compressor assimilation superheat 80C 8) Subcooling at condenser aperture 5C .

Figure 15 Compressor prices (capacity at -35C suction) 35C delivery)

Commercial and automated applications with beyond air condensers usually accept the condensers alien from the compressor and out with the building, usually on the roof. This, however, may aftereffect in continued runs of commitment pipework and beneath certain affairs this leads to difficulties with fractional abstract afore the condenser.

In some climates, melancholia changes in ambient air temperature may additionally accord acceleration to problems.

Air condensers are advised to bout the accomplished ambient temperature acceptable and back it avalanche essentially beneath this value, the burden at the amplification valve basin may be bereft to ensure the adapted breeze of refrigerant. If this action is likely, adapted precautions, such as abbreviation the condenser accommodation or alteration to another amplification valve, may accept to be taken.

In animosity of difficulties that may arise with air condensers and the added costs involved, they are abundantly used, decidedly breadth there is no accustomed accession of bargain baptize of acceptable quality.

Air-cooled condensers are usually rated for about 15C temperature aberration between the air and abbreviating temperature. Air velocities, abstinent as the boilerplate acceleration over the condenser face area, are frequently amid 2.5 and 5.0 m/s. Calefaction alteration per unit apparent breadth varies with a cardinal of factors, but a bulk of 250 W/h per m of extended apparent would be typical.

Table 15 gives the acceptable concrete ambit and ability requirements for a ambit of air condensers.

Table 15 Ambit and ability requirements for air-cooled condensers

Heat bounce (kcal/h)/1000 at 15C temp. diff.

External ambit (mm)

Costs (US$)

A Length

B Breadth

H Absolute depth. (incl. base)

6.9 13.8 28.8 46.8 57.7 80.7 126.8 184.5 230.5

1 x 0.6 2 x 0.6 3 x 0.6 2 x 0.9 3 x 0.9 2 x 3.2 3 x 3.2 4 x 3.2 4 x 3.2

1 220 2 000 2 320 2 650 3 250 3 920 4 830 5 945 5 945

705 805 1 010 1 110 1 315 1 620 1 925 2 280 2 280

798 798 836 1 047 1 047 1 075 1 075 1 075 1 113

750 1 050 1 800 2 400 2 700 3 600 5 250 7 200 9 000

Note: The aloft ratings are for R12 with 3C subcooling

It should be acclaimed that alteration factors may accept to be activated depending on the refrigerant, and this is acutely declared in manufacturers. catalogues.

Water from a basal accession is big-ticket and should alone be acclimated breadth the bulb is small and air-cooling is impractical.

Water from accustomed sources, such as rivers, lakes and wells, requires to be of a acceptable affection so that it does not bite the condenser or abhorrent the calefaction exchange surfaces. Chemicals, alluvium and biological contaminants such as algae are potentially damaging and best levels recommended by manufacturers may crave the baptize to be filtered or advised chemically.

Uncertainty about the chain of baptize aliment should additionally admission whether a baptize con- denser is used, abnormally back it is advised that baptize aliment are likely to be added belted during hot acclimate back the cooling appeal is greatest.

The best accepted blazon of water-cooled condenser is the shell-and-tube blazon breadth the baptize passes through the tubes. End covers are adapted to be removed periodically to apple-pie the tubes, therefore, condensers should be sited to accord admission for this operation (Figure 16).

Figure 16 Baptize claim of shell-and-tube condensers

Shell-and-tube condensers can either be army with the tubes accumbent or vertical and the attainable attic amplitude and roof approval may behest which blazon is used.

Different breeze patterns are additionally acclimated and afresh the best is mainly based on convenience. For instance, there may be a claim for the baptize admission and exit admission to be at the aforementioned end of the tube.

Water-cooled condensers are added bunched than the air-cooled due to the bigger heat alteration amid the baptize and the tube surface, which is about 15-20 times bigger than the air to apparent calefaction alteration in an air-cooled condenser. Water-cooled condensers, however, do not consistently accept fins to extend the calefaction alteration surface, therefore, the aberration in admeasurement is not as arresting as the aberration in calefaction alteration bulk would suggest.

If the temperature of the baptize accession is acceptable to change abundantly to affect the achievement of the thermostatic amplification valve or added refrigerant breeze control, condenser burden can be readily controlled by applicable a pressure-operated baptize valve which reduces baptize breeze back the condenser burden is bargain by circulating colder baptize than the architecture value.

Condensers are advised for a baptize breeze bulk of about 1.5 m/s through the tubes, and a temperature acceleration amid basin and aperture of about 5C, but this may alter from one architect to another, or it may be aloft if baptize is not plentiful.

Table 16 gives the acceptable concrete ambit and baptize burning for a ambit of shell-and-tube condensers.

Table 16 Shell-and-tube condensers

Capacity (kcal/h)/1000

Condenser dimensions

Water (kg/h)

Cost (US$)

Length (mm)

Diam. (mm)

(sw)

(fw)

2.1 10.7 21.5 43.0 64.4 107.4

760 760 760 1 524 2 286 2 286

90 115 165 165 165 216

420 2 140 4 300 8 600 12 880 21 480

252 732 1 065 1 725 2 250 2 850

157 480 765 1 215 1 530 1 860

Notes: (1) sw = alkali water; fw = beginning water (2) based on a 12C temperature aberration amid basin baptize and condenser saturation temperature, and a 5C baptize temperature acceleration

Air and baptize cooling are accumulated in an evaporative condenser with an advantage over air cooling, both in agreement of calefaction alteration and lower abbreviating temperatures, and over baptize condensers with a abundantly bargain baptize consumption.

In an evaporative condenser air is fatigued advancement over the condenser pipes and baptize is sprayed over the surfaces from aloft (Figure 17). Calefaction alteration after-effects in the evaporation of some of the baptize abounding over the coils and the resultant baptize vapour is discharged to atmosphere with the avenue air.

Figure 17 Evaporative condenser

As with air condensers, evaporative condensers crave to be positioned so that air can be broadcast advisedly and back the acquittal air additionally contains a acceptable accord of water vapour, the condenser allegation consistently be sited alfresco or the air ducted outside.

Theoretically, the baptize evaporated is about 2.7 kg/1 000 kcal of refrigeration effect, which is able-bodied beneath the nominal bulk of 200 kg adapted for a shell-and-tube condenser. Some water, however, is absent by baby aerosol actuality absolved with the air and a adapted overflow from the condenser backlog is all-important to accrue debris and added contaminants at a appropriately low akin of concentration.

Water burning in an evaporative condenser in convenance is, accordingly about 4-5 kg/1 000 kcal of algidity effect.

The acceptable dimensions, ability requirements and baptize burning for a ambit of evaporative condensers is accustomed in Table 17.

Some of the allowances from altered types of condenser can be accumulated back two or more of the basal systems of calefaction alteration are used.

A shell-and-tube condenser can be acclimated with apportionment of the cooling baptize if it is piped to either an evaporative acknowledgment or air acknowledgment at a appropriately alien armpit (Figure 18). This offsets the allegation for a continued run of algidity pipework, appropriately alienated the associated algidity problems and, also, alienated accepting aerial burden pipes where they are accessible to accident or breadth leaks would actualize a affirmation hazard.

Table 17 Affected beaker evaporative condensers

Capacity (kcal/h)

Fans (hp)

Pumps (hp)

Dimensions

Cooling baptize consumption (l/h)

Pump apportionment rate (l/min)

Cost (US$)

L (mm)

W (mm)

D (mm)

12 000 15 000 30 000 60 000 90 000 150 000

1.0 1.0 1.0 2 x 1.5 2 x 3.0 2 x 3.0

0.5 0.5 0.5 1.0 1.0 1.0

2 120 2 120 2 527 2 426 2 490 2 972

914 914 914 1 828 2 742 2 742

1 000 1 000 1 000 1 302 1 600 1 600

40 50 100 200 300 500

63.6 63.6 63.6 118.2 205.0 205.0

2 550 2 590 2 650 2 850 3 150 4 050

Note: This table is based on a wet-bulb temperature of 27C, a abbreviating temperature of 40C, and an abbreviating temperature of -40C

Figure 18 Condenser with alien baptize cooling

The chat evaporator, by accepted use, now includes all coolers alike back no evaporation takes place, such as in a adjustment appliance a accessory refrigerant.

The evaporator is in aftereffect the calefaction exchanger breadth calefaction from the product, or medium to be cooled, is transferred to the refrigerant.

Evaporators are fabricated in abounding altered forms depending on the algidity adjustment and the application. In some cases they may anatomy an basal allotment of the basal equipment, such as the plates of accumbent and vertical bowl freezers or the boom of a boom freezer. In added systems, the evaporator is an boilerplate calefaction exchanger or aqueous receiver, such as in abounding accessory and primary algidity applications. Abounding of these special cases are dealt with, or mentioned abroad where, and accordingly alone the basal blazon of evaporator used, which is for an air-to-refrigerant calefaction transfer, is advised in detail.

Evaporators for air-to-refrigerant calefaction alteration in air-blast freezers and algid stores are either fabricated from apparent aqueduct or finned pipe. Apparent aqueduct evaporators are now little used for alteration of calefaction from air back they are added expensive, crave a substantial acknowledging structure, booty up added amplitude and crave a ample continuing allegation of refrigerant. Apparent pipes, however, may be acclimated back calefaction alteration from the aqueduct apparent is high, such as from a refrigerant to a alkali in a accessory system.

By far the best broadly acclimated are finned aqueduct evaporators which are congenital as compact units with fan-assisted apportionment of air. Bowl evaporators accept additionally a limited appliance for air-cooling systems, decidedly back the calefaction alteration claim is not aerial and frosting of finned tube evaporators may be critical.

The abstracts acclimated for evaporators allegation be accordant with the refrigerant and also with the ambiance in which they are sited. For instance, chestnut allegation not be acclimated with R717 (ammonia) and adapted appliance should be accustomed in a alkali burdened marine environment.

Finned tube evaporator units are fabricated for wall, roof or attic ascent and the choice would depend on the accessibility of agreement them in any of these positions.

Defrost is an important appliance for evaporators operating beneath 0C. Frost accession on the calefaction barter surfaces abundantly reduces the calefaction alteration adequacy of the evaporator and this action would become analytical back the frost bridges the gap between adjoining fins and abundantly reduces the apparent breadth attainable for calefaction transfer.

In abate units, electrical defrost is acclimated with the boiler elements congenital in as part of the unit. This is big-ticket and for beyond units added methods are used, which may either be alien or internal. Baptize or an anti-freeze band-aid can be periodically caked over the apparent and drained away. This method, however, is not consistently convenient, abnormally back low temperature altitude accept to be maintained at all times as they are in a algid store. Centralized defrosting by agency of hot gas redirected from the condenser acquittal is added usual, but in adjustment to do this finer added than one evaporator must be operated from the aforementioned abbreviating assemblage and the evaporators defrosted in sequence. Reverse aeon defrosting, breadth the functions of the evaporator and condenser are reversed, is addition adjustment acclimated with baby units.

Fin-spacing is additionally an important aspect of architecture and a accommodation has to be made amid a abutting agreement giving a bunched assemblage and a added agreement which after-effects in a beyond assemblage but allows added frost to accrue afore a defrost is necessary. Fin spacing of 6, 8 and 12 mm are attainable in some accepted evaporator ranges.

Each case allegation be advised alone but, in general, a agreement of 6 mm may be acclimated back frost accession is not critical, a agreement of 12 mm back there is acceptable to be a abundant accession of frost, and 8 mm for a accommodation situation.

Another important appliance in selecting an evaporator is the characteristics of the fan. If the evaporator is chargeless standing, as it is in an attainable algid store, and there is no allegation for the air to be broadcast over a ample area, ballista blazon adorable admirers may be used: These have: simple blades shaped from flat, breadth metal and they are inefficient back there is a attrition to air flow.

In air-blast freezers and in algid aliment breadth the air is adapted to be “thrown” over a distance, aerofoil brand admirers are required. The blades are advised with a able-bodied shaped contour agnate to the addition of an aeroplane and they are a acceptable accord added able than the cheaper ballista type.

Standard ranges of wall/roof and attic army evaporators are listed in Tables 18, 19 and 20, calm with their all-embracing dimensions, weights and fan ability requirements.

Table 18 Wall/roof army coolers/evaporators- Ballista admirers –

Refrigeration accommodation (kcal/h)

Fin agreement (mm)

Fan ability (W)

Air aggregate (m/s)

Air bandy (m)

Dimensions

Approx. Weight (kg)

Cost (US$)

L (mm)

B (mm)

D (mm)

344

1 x 7

525

375

180

6.5

350

686

1 x 15

690

375

180

8.0

420

1 615

2 x 15

1 120

375

230

15.5

450

2 017

6

1 x 125

.57

9.8

1 000

502

428

36.0

500

2 322

4

570

3 372

6

2 x 125

1.08

9.8

1 440

502

428

51.0

600

4 300

4

720

7 455

6

2 x 330

2.02

19.8

2 080

502

508

94.0

1 060

8 600

4

1420

11 100

6

3 x 330

3.03

19.8

2 965

502

508

126.0

2 100

12 900

4

2 849

Table 19 Wall/roof army coolers/evaporators – Aerofoil admirers –

Refrigeration accommodation (kcal/h)

Fin agreement (mm)

Fan ability (W)

Air aggregate (m/s)

Air bandy (m)

Dimensions

Approx. Weight (kg)

Cost (US$)

L (mm)

B (mm)

D (mm)

2 017

6

1 x 125

0.57

23

1 000

502

428

35

620

2 322

4

670

3 372

6

2 x 125

1.08

23

1 440

502

428

49

750

4 300

4

900

7 455

6

3 x 330

1.87

32

2 080

502

508

94

1 250

8 600

4

1 650

11 100

6

3 x 330

3.03

32

2 965

502

508

126

2 400

12 900

4

3 350

Table 20 Attic army coolers/evaporators

Refrigeration capacity (kcal/h)

Fan power (W)

Air throw (m)

Dimensions

Approx. weight (kg)

Cost (US$)

L (mm)

B (mm)

D (mm)

9 000 14 000 25 000 53 000 64 000

2 x 820 2 x 1 050 2 x 1 350 3 x 3 060 3 x 4 100

27 27 27 40 40

2 413 2 743 3 200 4 673 4 673

1 320 1 320 1 320 1 420 1 420

1 016 1 220 1 625 2 083 2 438

295 490 886 1 955 2 364

6 200 6 450 7 800 12 300 14 400

Plate evaporators are either acclimated in units consisting of a coffer of plates on one framework and about accumulation a fan for air circulation. or as distinct plates which may be abiding adjoin a coffer or roof with accustomed apportionment of the air. Types of plates acclimated in bowl evaporators are:

In adjustment to adapt the breeze of refrigerant, advance architecture operating altitude and acquiesce accessories to be operated cautiously and economically, a cardinal of controls are acclimated with algidity systems.

The complication of a ascendancy adjustment usually relates to the admeasurement of the plant, ranging from no added than a capillary throttling accessory to adapt refrigerant breeze in a small abstruse adjustment to complex, computer-based ascendancy systems for the added afresh installed large, assorted assemblage systems.

Some of the controls acclimated for the admeasurement of bulb added acceptable in the fishing industry are listed below. A abrupt adumbration is accustomed of the requirement. function. whether spares are adapted and the acceptable cost.

Pressure gauges are acclimated to announce plant-operating altitude and they are therefore advantageous for accepted inspections and, also, back fault-finding. Gauges are normally positioned at the compressor to announce pressures on the aerial and low burden abandon of the adjustment with added gauges, as necessary, to announce the boilerplate burden in a two-stage adjustment and the commitment burden of the compressor lubricating oil pump. An added barometer may be acclimated in a beyond adjustment to announce the burden at the evaporator and, also, the pump commitment burden back a accessory refrigerant is used.

To awning all these requirements, three altered burden ranges may be required, and although they are not basal for the bulb operation, spares should be attainable since a reliable barometer would admonition to abate both operational and aliment costs.

The bulk of gauges will alter amid US$ 5 and US$ 25.

Like burden gauges, temperature gauges, or abridged thermometers, are acclimated to monitor plant-operating altitude and to abetment with fault-finding. Thermometers acclimated with the algidity compressor are acclimated to adviser temperatures at the aforementioned positions as the refrigerant burden gauges back both readings are frequently adapted to appraise the plant-operating condition.

Additional temperature gauges are additionally accessible to admeasurement cooling baptize temperature, the temperature of a accessory refrigerant or the temperature of a low pressure, primary refrigerant, aqueous reservoir.

Dial gauges are additionally acclimated to adviser the temperature in air-blast freezers, but for algid aliment a recording thermometer is adapted back this admonition is about required for blockage later.

Dial thermometers bulk amid US$ 15 and US$ 25. Steam thermometers bulk amid US$ 3 and US$ 8. Circular blueprint recorders bulk about US$ 350.

At atomic two temperature ranges are adapted to awning all these requirements, and the availability of spares is not frequently analytical back thermometers can usually be alternate afterwards breaking into the system, or a hand-held thermometer, acclimated in an adapted way, can be substituted.

Figure 19 Burden and temperature measurement

Control of refrigerant breeze is apparently the best important ascendancy to be exercized in a algidity system. The afterward are four examples of ascendancy acceptable to be used:

Hand amplification valves are about adapted in alongside with added ascendancy accessories so that they can be manually operated in the case of a failure. Bulk US$ 30-60, depending on size.

Thermostatic amplification valves (tev) are fabricated in a advanced ambit of sizes and models and the afterward annual will, therefore, alone accord an about adumbration of the acceptable cost.

US$ 15 for tev with accommodation of 1000 kcal/h US$ 50 for tev with accommodation of 9 000 kcal/h US$ 135 for tev with accommodation of 90 000 kcal/h US$ 150 for tev with accommodation of 165 000 kcal/h

A added valve should consistently be available, but the accession of a duke expansion by-pass can be acclimated for a abbreviate time in an emergency.

The akin ascendancy is basal to the operation of the system, therefore, a added should be attainable or, depending on the blazon used, spares for the added accessible genitalia should be held. Bulk US$ 200-350.

Safety accessories arise into two categories: those for attention the accessories and those for the environment. Best baby units accomplish afterwards affirmation accessories back replacement costs are low and irreparable accident beneath likely. Also, with abate units, artlessness is consistently desirable. Beyond units, however, from about 20 hp and upwards, would accept one or added of the afterward devices:

Capacity ascendancy of a algidity adjustment can be able in abounding agency and the afterward annual gives some of the methods acceptable to be acclimated in angle freezing and cold storage:

Off-loading of cylinders in a multicylinder compressor . By-passing from de 1 i actual to assimilation at the compressor On/off-cycling of the compressor by either a temperature or pressure-sensing device, Acceleration ascendancy of the drive motor either by electrical or automated agency ,

A able actuality should be consulted on whether this claim is all-important and on the best of adjustment used.

Liquified gases are acclimated about alone for freezing abate angle articles in connected freezers,

There are three liquified gases frequently acclimated for this purpose:

Liquid nitrogen (N2) Aqueous carbon dioxide (CO2) Aerial abstention R12 (liquid freon freezant or LFF)

Liquid nitrogen is sprayed over the artefact afterwards it has been precooled or conditioned in the nitrogen gas during the aboriginal stages of freezing, Freezing by absolute captivation in aqueous nitrogen cannot be acclimated back it after-effects in actual quick temperature change in the artefact and this “thermal shock” after-effects in concrete damage,

Liquid carbon dioxide sprayed into the freezer after-effects in the absolute formation of both solid and aerial forms of CO2. The solid anatomy is deposited as a accoutrement of “snow” on the apparent of the product and sublimation of this “snow” at -78,5C is amenable for best of the algidity effect.

Liquid freon freezant is either sprayed on the artefact or acclimated with absolute captivation of the product, or a aggregate of both of these methods can additionally be used, In the case of an LFF system, clashing the others, the evaporated refrigerant is recondensed by agency of a automated algidity adjustment and reused with alone a baby accident of up to 3%.

Table 21 lists the concrete backdrop and added abstracts of the three refrigerants.

Table 21 Liquified gas refrigerants acclimated in attainable systems

Data

N2

CO2

LFF

Chemical name

Nitrogen

Carbon dioxide

Dichlorodifluoromethane

Common name

Liquid nitrogen

CO2 liquid

Liquid freon freezant Freon aliment freezant

Chemical formulae

N2

CO2

C, Cl2, F2

Appearance liquid

Clear

Clear

Odour

None

Slight pungent

Faint ethereal, musty

Toxicity

Low

Low

Low

Density kg/m

784

464

1 485

Specific calefaction aqueous kJ/kg C

1.04

2.26

.984

Latent calefaction kJ/kg

358

352

297

Total attainable algidity aftereffect kJ/kg

690

565

297

Boiling point C

-196

-78.5 (sublimation temperature)

-29.8

Thermal conductivity

.29

.19

.095

Consumption/100 kg artefact frozen

100-300

120-375

1-3.0

Price 9/83 and quantity

$90/tonne 250 t/year

$128/tonne 250 t/year

1,500/tonne in 67 kg cylinders

Freezers for angle and angle articles can be disconnected into four basal groups depending on the adjustment of calefaction alteration used:

Air blast Contact Immersion Liquified gases

The aloft basal groups are dealt with later, breadth added specific accommodation are given about. their architecture and uses in the fishing industry, The afterward abrupt description accordingly alone gives a actual ample outline of their basal characteristics.

Air-blast freezers – broadly acclimated for about all angle and angle articles back their main affection is a versatility to benumb articles of all shapes and sizes, They are constructed for batch, connected and batch/continuous modes of operation and accordingly can be used for baby operations as able-bodied as in all-embracing assembly lines.

Contact freezers – this blazon of freezer has additionally abounding applications for fish-freezing with vertical bowl freezers (VPF) and accumbent bowl freezers (HPF) actuality the most accustomed types. The basal use of VPF and HPF is to benumb regular-shaped angle articles such as blocks, bales and cartons.

Another blazon of acquaintance freezer, which is a connected action appliance a alternating drum, has additionally a bound use for freezing IQF articles such as angle fillets.

Plate freezers are added accustomed as units for accumulation freezing, but some designs for a connected operation are available.

Immersion freezers – this blazon of freezer has now alone a bound use and some of the applications, which ahead acclimated an captivation process, accept afflicted to added freezing methods. Sodium chloride alkali and salt/sugar solutions are two fluids which may be still advised for adapted purposes.

Liquified gases – these are acclimated mainly breadth refrigerant aliment are readily attainable and are about cheap. The gases are acclimated mainly for connected freezing processes and nitrogen, carbon dioxide and a aesthetic anatomy of R12 are refrigerants which accept been acclimated for angle freezing applications.

Air-blast freezers can be subdivided according to their approach of operation, adjustment of loading and adjustment of air flow. Some of the acceptable combinations can be acquired from the block diagram in Table 22.

Batch freezers are added able than continuous, therefore, if a array of products are to be frozen, a accumulation freezer may be selected. Accumulation freezers are additionally acceptable to be acclimated for articles with best freezing times back with a accumulation freezer there is better appliance of attic amplitude due to the multi-layer adjustment of loading. It is difficult to adjudge on an exact band of demarkation but freezing times best than one hour would usually crave a accumulation approach of operation. (See Abstracts 20, 21 and 22.)

Continuous freezers are best acclimated for freezing alone portions, such as single fillets and baby shellfish, such as bald prawns and scallops. The basal advantage in appliance a connected freezer for these abate and/or thinner articles is that back they benumb bound they will additionally thaw bound and the delays that action with a batch-freezing operation may be overlong. Connected freezing allows quick administration afterwards freezing and a quick alteration to the algid store.

Batch/continuous freezers are usually accumulation blazon freezers operated with trolleys which are loaded in adjustment at fixed-time intervals rather than all at one time as in the truly accumulation freezer.

Table 22 Types of air-blast freezer

Method of Loading

Air Flow

Trolleys

Cross Flow

Pallets

Series Flow

Shelves or racking

Trolleys

Cross Flow

Pallets

Series Flow

Plain belt

Cross Flow

Mesh Belt

Series Flow

Link Belt

Link Belt

Cross Flow

Series Flow

Upward Flow

Mesh Belt

Upward and Cross Flow

Link Belt

The blazon of freezer acclimated will depend on the specific requirements of anniversary installation and the afterward abrupt addendum will admonition with this choice

Figure 20 Accumulation air-blast freezer with ancillary loading and unloading

Figure 21 Batch-continuous air-blast freezer with counterflow air circulation

Figure 22 Batch-continuous air-blast freezer with crossflow air circulation

This allows the aftermath to be bound loaded into the freezer rather than accept delays while cat-and-mouse for abounding loads. The cardinal of trolleys and the loading breach are selected to ensure that back the freezer is absolutely loaded a new trolley will be exchanged with one which has been in for the all-important freezing time and, thereafter, a one out and one in adjustment is operated. This loading adjustment additionally ensures that the algidity appeal is added analogously advance than would be the case for a accumulation freezer (Figure 23).

A batch-continuous freezer blueprint and airflow adjustment should be advised to ensure that a new bulk of balmy angle is not placed upstream of a partially arctic load.

Trolleys are added adaptable but booty up added amplitude on the branch floor. Bassinet endless can be confused anon from the freezer to a algid abundance for acting accumulator afterwards the need for demography big-ticket accessories out of service.

Fixed shelves aural the freezer are not recommended back the freezer aperture allegation be larboard attainable during loading. This may booty a ample time and aftereffect in an unnecessary aerial admission of calefaction and baptize vapour with the air entering the freezer. With a fixed shelf adjustment some of the air-blast freezer’s versatility will additionally be lost.

Spiral freezers are advised to abate the attic amplitude claim of the freezer but they, in turn, crave a college roof approval and in some cases this may be equally critical. Circling freezers additionally tend to alter the appearance of some articles due to the curvature of the belt path. In band freezers accept been congenital with a multi-belt operation in adjustment to abate the attic amplitude (Figure 26). Alteration of partially arctic angle from one belt to another. however, may be difficult and aftereffect in accident or baloney of the product. This transfer, however, is able with some bulk of success in a semi-fluidized freezer with some articles by ensuring that the wet artefact does not adhere to the aboriginal belt (Figure 27).

Figure 23 The aftereffect on temperature and algidity accommodation back loading a accumulation air-blast freezer

Figure 24 Connected belt air-blast freezer with crossflow air circulation(also complete with countercurrent alternation breeze air circulation)

Figure 25 Connected air-blast freezer with the belt abiding in a spiral

Figure 26 A triple-belt air-blast freezer

Figure 27 Semi-fluidized breeze freezer with bifold belt

Figure 28 A fluidized breeze air-blast freezer

Mesh and articulation belts can be acclimated with angle which are unskinned, if the bark is arranged to be in acquaintance with the belt. Freezing skin-off fillets and added angle and fish products, which allegation be arctic with the beef in acquaintance with the belt may, however, prove to be difficult, with accident to the artefact and accident of crop due to accident when absolution the arctic product. Collapsed belts fabricated from breadth stainless animate are now acclimated with in-line freezers, and best articles can readily be arise afterwards damage. Also, with a collapsed belt, decidedly aerial articles can be arise by defrosting the belt at the avenue of the freezer by spraying the abject of the belt with water.

Whether one adjustment of breeze or addition is acclimated depends mainly on the agreement of the freezer and, afore chief on this aspect and added appearance of the architecture and layout, the afterward should be considered:

– absolute aggregate of air flow – temperature acceleration of the air over the product – breeze alone from colder to warmer products – large-face breadth of the acknowledgment adapted for minimum frost interference – burden differences aural the freezer in affiliation to doors and openings – burden bead about the ambit and the aftereffect on fan power

A ability of both the advised freezer operation and the elements of acceptable engineering and calefaction alteration convenance will, therefore, be adapted afore a final accommodation is taken.

Only a asperous adviser can be accustomed on the bulk of air-blast freezers since, clashing other types of freezer, it is the barring rather than the aphorism to buy them as accepted designs from an accustomed ambit of sizes, decidedly in the case of accumulation freezers. Batch air-blast freezers are usually congenital on armpit to clothing alone requirements and local costs may, thereby, annual for a acceptable admeasurement of the absolute cost.

Some admonition on costs, however, is presented in graphical anatomy in Abstracts 29-33. In these costings the algidity accouterment is included, but this may not consistently be the case.

Care should consistently be taken to ascertain what the bulk includes back authoritative comparisons amid freezers.

A accommodation has to be fabricated in the architecture air acceleration of an air-blast freezer back high air speeds and acceptable calefaction alteration additionally beggarly college costs. Bulk 34 shows a typical accord amid air acceleration and freezing time with continued freezing times at low air speeds and little to be acquired if college air speeds are used. Air acceleration affects the apparent calefaction alteration only, therefore, the admission on all-embracing calefaction alteration depends on the accord of this apparent aftereffect to the calefaction transfer, through the artefact and packaging. Bigger apparent calefaction alteration would, for instance, accept beneath aftereffect on the freezing time of thicker articles or articles which are captivated afore freezing.

Experience has apparent that an air acceleration of 5 m/s is a acceptable boilerplate bulk for batch air-blast freezers and this should ensure that there is an able air acceleration throughout the freezer space. With best freezing times, such as in freezers advised to freeze thicker articles overnight, lower air speeds may be justified, but it is absurd that this air acceleration would be beneath than about 3 m/s.

Figure 29 Accumulation freezers (including refrigeration)

Figure 30 Connected circling freezers (including refrigeration)

Figure 31 Connected single-mesh belt in-line freezers (including refrigeration) ,

Figure 32 Fluidized freezers (including refrigeration)

Note: The aloft costs were for a PEA freezing operation. Although there will be some aberration back freezing baby shrimp the costs will be of abundant the aforementioned adjustment of magnitude

kg/h

Figure 33 Collapsed belt connected in-line freezer (including refrigeration)

Figure 34 Aberration of freezing time with air acceleration in an air-blast freezer

Since connected air-blast freezers can booty up a acceptable accord of attic space, there is an allurement to advance the calefaction alteration and abate the freezer admeasurement by appliance college air speeds.

An air acceleration of 10 m/s has been acclimated in a connected air-blast freezer and back the blazon of artefact arctic is either baby or thin, this college air acceleration has a significant aftereffect on the all-embracing calefaction transfer. Aerial air speeds allegation alone abide in the working breadth of the freezer, therefore, an adjustment such as that apparent in Bulk 24 will ensure that the fan ability is not excessive.

Even in able-bodied advised freezers the calefaction alien by the fan may annual for 20-25% of the algidity claim and in a abominably advised freezer fan calefaction may alike beat the calefaction to be removed from the product.

The architecture temperature of an air-blast freezer should be accompanying to the temperature of the algid abundance to which the artefact is transferred afterwards freezing. Acceptable freezing practice should ensure that the artefact is arctic bottomward to an boilerplate temperature according to the advised accumulator temperature, and in adjustment to accomplish this, the air temperature in the freezer should be at charter 5C lower. For example, with a accumulator temperature of -30C, the associated air-blast freezer will crave to accept an air temperature of -35C and for -25C storage, the air temperature should be -30C.

Lower operating temperatures may occasionally be justified in adjustment to accomplish quicker freezing times, but this adds to the bulk of freezing and there may be problems with the leaks into the algidity adjustment due to the low pressures associated with the low temperatures.

The attic breadth adapted for a freezer will acutely depend on its freezing capacity, but it additionally depends on the blazon of the freezer and the artefact to be frozen.

Bigger freezers tend to use amplitude added economically as can be apparent from the following examples of accumulation freezers for freezing trays of angle on trolleys:

Capacity (kg/h)

Floor amplitude (m)

100 1 000

10 50

A apathetic freezing artefact will crave a beyond freezer than a faster artefact and this is illustrated by the afterward comparison:

Freezer

Capacity (kg/h)

Freezing time (h)

Freezer bulk (kg)

A

100

1

100

B

100

2

200

Both freezers accept the aforementioned capacity, but due to the best freezing time in B, the freezer requires to authority bifold the bulk of freezer A which will be loaded and emptied alert during the two hour period.

A allegory is fabricated amid the attic breadth requirements of altered types of air-blast freezer in Table 23. All freezers accept a accommodation for freezing 700 kg/h of IQF fillets.

Table 23 Attic amplitude claim of air-blast freezers

Type of freezer

Floor breadth (m)

215

260

85

100

170

a/ Alone acceptable appliance would be for cooked, shell-off baby shrimp and other articles of agnate nature

All amplitude requirements quoted in Table 23 are for the freezer chiffonier only, but other amplitude requirements allegation additionally be added.

Only in actual baby freezers will the algidity accouterment be congenital as allotment of the freezer unit, positioned either aloft or beneath the freezer cabinet. Accouterment is accordingly amid out with the alive breadth and finer in a abstracted room.

Floor amplitude is adapted for loading and auction the freezer, and amplitude may additionally be adapted for a complete added set of trolleys or pallets so that they can be loaded and cat-and-mouse for the abutting freezing cycle.

Batch freezers are about congenital on armpit as an basal allotment of the building, but ahead complete or free-standing freezers should be larboard with a amplitude about them for analysis and aliment of the cloistral structure.

Space may additionally be adapted for absolution arctic angle from trays or frames and, in turn, amplitude and accessories for charwoman and accumulator of the trays will additionally be required.

The amplitude requirements of a freezer may accordingly beat the amplitude active by the freezer chiffonier and it is this absolute amplitude claim that should be acclimated in making comparisons and calculations. With the added amplitude requirements taken into annual the accord amid the freezers apparent in Table 23 may accordingly be absolutely different.

Freezing times are bent by the size, appearance and packing of the artefact together with the temperature and air acceleration in the freezer. The freezing aeon depends both on the freezing time and the time taken to bulk and unload the freezer.

If added considerations admittance it, freezing aeon times should be called to give optimum use of the freezer. For instance, a change in artefact array may acquiesce the aeon time to fit absolutely into a alive day and appropriately the freezer will be absolutely utilized, as apparent in the afterward comparison:

Working day (h)

Starting and stopping (h)

Time for freezing (h)

Cycle time (h)

Cycles

Utilization (%)

8.5

1

7.5

2.5

3 x 2.5

100

8.5

1

7.5

3.0

2 x 3

80

Horizontal bowl freezers (HPF) are acclimated for freezing accustomed shaped packs of fish. The artefact is arctic in cartons, freezing frames or lidded trays which accomplish absolute contact with the plates through which the refrigerant is circulated.

Figure 35 Accumbent bowl freezer

The accumbent plates are apprenticed calm to a agreed spacing, set by the artefact thickness, and the acquaintance burden is maintained by a hydraulic accessory during the freezing process.

The coffer of freezer plates basal the assemblage is frequently absolute in an insulated asylum which is lined internally and evidently with galvanized or coated metal sheeting. Admission to the freezer stations is either by agency of vertically-lifted curtains or doors, at the advanced and rear.

The accommodation of a HPF assemblage depends on the artefact thickness, bowl admeasurement and the number of stations and, aural the acute banned of the assorted combinations available, freezers can be complete to clothing alone requirement.

Plate sizes may alter amid one architect and addition and anniversary may alone action a best of three accepted sizes for their complete ambit of freezers.

A architect may accept a ambit of freezer units with up to 20 stations but, obviously, the added the agreement amid plates the beneath would be the best cardinal of stations in adjustment to accrue the freezer acme reasonable.

When selecting the amplitude adapted amid plates, it is accepted to accept the best plate aperture 25 mm added than the array of the artefact to acquiesce accessible loading. (Tables 24 and 25.)

When artful the weight that can be arctic in a HPF the cardinal of bales and the weight of angle absolute in anniversary amalgamation accept to be taken into account.

Plate ambit and amalgamation sizes should be akin to abstain boundless decay of abeyant freezing amplitude and it is accepted to accomplish about a 75% bowl coverate in practice.

Although freezers can be supplied with added bowl spacings, it is accepted to benumb fish articles in packages, trays or basal frames with a abyss not greater than 50 mm to 75 mm.

Individual calculations will crave to be fabricated for anniversary appliance to admission accurate abstracts but an adumbration of the loading of alone freezer stations is accustomed in Table 26 for guidance.

The use of freezer trays and freezer frames (Figure 36), depends on the blazon of product to be frozen. Cartons, added containers and blocks of angle with alone nominal dimensions are frequently arctic in trays. For the assembly of blocks with a claim for precise dimensions, freezing frames are necessary, but afresh these may be placed on a abject tray to facilitate loading and unloading.

Refrigeration systems acclimated with HPF are:

Table 24 Ambit and aircraft weights for accumbent bowl freezers (See Table 25 for bowl sizes)

No. of stations

Dimensions (mm)

Weight (kg)

A

B

C

D

E

F

G a/

5

1 460

2 360

1 400

350

200

420

425

1 840

6

1 890

7

1 940

8

1 880

640

2 020

8

1 650

2 420

9

1 400

2 100

9

1 650

2 550

10

1 400

2 160

10

1 650

2 670

11

2 800

12

2 155

2 930

12

2 790

3 250

13

2 360

3 040

13

2 790

3 400

14

2 360

3 270

14

2 790

3 580

15

2 580

2 360

3 400

15

3 630

16

4 130

17

4 210

18

4 290

19

4 370

20

4 450

a/ For shipping, the hydraulic butt can be removed. Best aircraft height is accordingly accustomed by A and F

Table 25 Accumbent bowl freezer-plate sizes and openings

No. of stations

Dimensions (mm)

Plate sizes

Plate openings

(max)

(min)

5

1 550 x 820

108

38

6

95

38

7

90

38

8

108

38

8

1 550 x 1 120

108

38

9

1 550 x 820

100

38

9

1 550 x 1 120

100

38

10

1 550 x 820

94

38

10

1 550 x 1 120

94

38

11

89

38

12

102

38

12

1 930 x 1 120

102

38

13

1 550 x 1 120

90

32

13

1 930 x 1 120

90

32

14

1 550 x 1 120

83

32

14

1 930 x 1 120

83

32

15

1 550 x 1 120

90

32

15

1 930 x 1 120

90

32

16

86

32

17

82

32

18

79

32

19

75

32

20

70

32

Table 26 Accumbent bowl freezers Boilerplate net weight of artefact per station (kg)

Product and thickness (mm)

Standard bowl ambit (mm)

1 550 x 820

1 550 x 1 120

1 930 x 1 120

Whole fish

50 75

45 68

59 88

71 106

Fish fillet

50 75

59 88

77 116

95 143

Figure 36

The pump apportionment adjustment is recommended for ample accommodation freezers or multiple freezer installations in adjustment to accomplish a good, compatible calefaction alteration in all freezer plates. For accessory pump apportionment systems calcium chloride alkali or trichloroethylene are the best frequently acclimated refrigerants, but due to the college basal bulk of this system it is usually bedfast to ample abyssal installations.

The force feed, abounding adjustment is the best broadly acclimated for boilerplate and large, single assemblage freezers. The low temperature backlog barge is army anon aloft the freezer to accord a bunched and able blueprint and operation.

Direct amplification systems are added adapted for abate freezer units breadth there will be beneath adversity in accomplishing acceptable refrigerant administration and appropriately uniform freezing.

Table 27 Pump apportionment ante for accumbent bowl freezers

Refrigerant

Circulation rate (litres/h/l 000 kcal)

67

251

196

251

435

570

Accurate freezing times are basal for artful the accommodation of a freezer and the times acclimated should finer be abstinent freezing times acquired by freezing samples of the artefact beneath the advised operating conditions. Afore appliance freezing times from added sources. advertence should be fabricated to sources giving added admonition on this subject back the freezing time can alter appreciably depending on a cardinal of factors.

Table 28 Accumbent bowl freezer -approximate freezing times (Pump circulating adjustment abbreviating at -34C)

Product array and freezing times

50 mm

62 mm

76 mm

100 mm

60 min

75 min

105 min

165 min

75 min

90 min

120 min

180 min

60 min

75 min

110 min

170 min

90 min

135 min

160 min

230 min

Table 29 Accumbent bowl freezer -approximate freezing times (Gravity feed abounding adjustment abbreviating at -34C)

Product array and freezing times

50 mm

62 mm

76 mm

100 mm

75 min

110 min

145 min

195 min

90 min

120 min

150 min

210 min

73 min

115 min

150 min

210 min

110 min

170 min

200 min

270 min

Defrost time and the time taken to bulk and unload the freezer additionally accept to be taken into annual back artful the freezing capability.

On best installations it is alone all-important to defrost already per day if no aqueous is agitated on the apparent of the freezer plates. The circadian defrost afresh may be achieved brief by abrogation both doors attainable although. on occasion, some abetment may be given by hosing the plates with apple-pie water.

If it is all-important to accomplish with a quick defrost amid anniversary freezer load, it may be all-important to accept a congenital defrost system. A quick defrost may additionally be adapted if the freezer was acclimated 24 h/day with alone 1-2 h accustomed for defrost and cleaning.

Assuming trays are preloaded and a abounding bulk is available, the accumulated loading and auction time for anniversary HPF aeon beneath ideal altitude should be about 15-20 min for boilerplate sized freezers and proportionally beneath or best for added sizes.

Before any alternative can be made, basal admonition allegation be established

The cardinal of cycles per day is:

When selecting accumbent freezers for 24-h operation, acquiesce 1-2 h beneath for defrost and cleaning.

The weight of artefact to be arctic during anniversary cycle:

The cardinal of stations required:

The abutting accomplished cardinal is taken. Should this bulk be aloft the best available, bisect so that acceptable appropriately stationed freezers can be selected.

Calculate the absolute calefaction agreeable of the artefact and add 20%.

Refrigeration accommodation required:

Where multi-installations are selected, the aloft accommodation may be bargain 5% for each added appropriately sized freezer up to a best of 15%, provided the loadings are staggered.

Evaporating temperature to be acclimated with the aloft algidity accommodation is accustomed in Table 30.

Table 30 Abbreviating temperatures of accumbent bowl freezers

Evaporating temperature

Approximate abbreviating range

-34C

-32/-42C

-34C

-32/-42C

-30C

-20/-27C

-34C added temperature bead beyond Accessory cooler

The algidity claim adding for an HPF allegation booty into annual allowances for the blazon of product, antecedent and final temperatures, trays, frames and packaging, insulation calefaction gains, pump activity ascribe and added accessible factors. In the absence of abundant admonition a bulk of 115 kcal/kg can be acclimated with some affirmation for chilled angle arctic afterwards added water. Added baptize will admission this bulk by 101 kcal/kg of baptize added.

Some added recommended ethics are accustomed for archetypal angle articles in Table 31.

Table 31 Accumbent bowl freezer algidity requirements

Product

Refrigeration claim (kcal/kg of product)

117

105

103

Notes: (i) Artefact antecedent temperature is 10C and final temperature about -30C (ii) Accommodation is for artefact only, excluding added water

Selection example

A chump requires to benumb 30 t of fillets in a 24-h alive day. The fillets are to be arctic in 50 mm blubbery blocks and the algidity bulb is to accomplish with an ammonia pump apportionment system. The antecedent artefact temperature is 10C and the final calm temperature -30C.

The freezer called will accordingly be one 17-station freezer adapted with 1 930 x 1 120-mm plates.

At this point the best bowl openings allegation be arrested to assure that a approval of at atomic 25 mm is attainable from a accepted range. Should a greater aperture be necessary, afresh a purpose-built assemblage will be required.

117 kcal/kg x 1 666 kg 1 h

If 10% baptize was added this would admission by 1 666 kg x 0.1 x 101 kcal/kg, agnate to 16 827 kcal/h

Refrigeration claim 194 922 16 827 = 211 749 kcal/kg

Table 32 Bulk of accumbent bowl freezers .

No. of stations

Plate size (mm)

Cost (US$)

5

1 550 x 820

14 250

20

1 930 x 1 120

27 750

5

1 550 x 820

28 500

7

1 550 x 1 120

32 250

The vertical bowl freezer (VPF) is alluringly ill-fitted for aggregate freezing of fish. and although originally advised for freezing angle at sea. it is now additionally acclimated abundantly on acreage mainly for freezing melancholia angle which are arctic in aggregate for processing throughout the year.

Figure 37 Twenty-station vertical bowl freezer with top auction arrangement

The artefact is loaded into spaces formed by air-conditioned plates which anatomy the stations of a vertical bowl freezer unit. The plates are hydraulically bankrupt thereby slightly absorption the artefact to a preset block array and additionally convalescent the acquaintance between the angle and the bowl surfaces.

After freezing, the algid refrigerant is angry off and a hot refrigerant accession is broadcast through the plates to defrost them and breach the band amid the plates and the product. This defrost action alone takes a few annual and, back complete, the hydraulic adjustment is operated to attainable the plates and accession the blocks to the top of the freezer accessible for removal.

Since the artefact is arctic into a balanced block, it is alluringly ill-fitted for palletizing to accord acceptable appliance of algid accumulator space. The artefact can be frozen unwrapped and stored afterwards packaging or arctic in cardboard or artificial accoutrements which are amid amid the plates afore loading the fish. Unwrapped articles may, however, be anesthetized or amid into cartons afterwards freezing.

The admeasurement of a VPF assemblage depends on the bowl size, bowl agreement and the cardinal of stations.

A bowl broadly acclimated has ambit of 1 120 x 558 mm which produces full-sized blocks barometer 1 060 x 520 mm. Added bowl sizes attainable from the aforementioned architect give block ambit of 1 180 x 490 mm and 800 x 806 mm. Added accepted sizes may, however, be attainable from added manufacturers. The accouterment of a non-standard bowl admeasurement will be big-ticket back this may crave a adapted die to boot the bowl sections.

The accepted block thicknesses produced in VPF are 50 mm, 75 mm and 100 mm, and by agency of adapted adaptors it is accessible to accept added than one accepted agreement in the aforementioned unit.

Any cardinal of stations can be supplied up to a absolute of about 30, but manufacturers will frequently alone accession bristles or six accepted sizes. Adapted requirements, such as small units for freezing trials or chic use, can, however, be fabricated on request.

When selecting the cardinal of stations per freezer unit, annual should be taken of the acceptable adjustment of angle supplies. Assemblage sizes should be called so that they are acceptable to be absolutely abounding during anniversary cycle, appropriately alienated the achievability of freezing partial endless or accepting freezers cat-and-mouse for added aliment to complete a load.

Overall ambit and weights for a abounding accepted ambit is accustomed in Table 33.

Table 33 Vertical bowl freezers Ambit and aircraft abstracts (uncrated)

Block thickness (mm)

No of stations

Dimensions amplitude x abyss x height (mm)

nominal weight

100

12

2 230 x 1 600 x 1 885

1 600

16

2 735 x 1 600 x 1 885

1 900

20

3 280 x 1 600 x 1 885

2 200

75

16

2 301 x 1 600 x 1 885

1 800

20

2 733 x 1 600 x 1 885

2 100

25

3 240 x 1 600 x 1 885

2 300

50

20

2 230 x 1 600 x 1 885

2 000

25

2 734 x 1 600 x 1 885

2 200

30

3 032 x 1 600 x 1 885

2 400

Note: Freezers accept accepted plates barometer 1 120 mm x 558 mm

To ensure a acceptable apportionment of refrigerant, and appropriately compatible freezing in all stations, vertical bowl freezers use pump apportionment of refrigerant. Both primary and accessory refrigerants are acclimated and all the refrigerants listed in Table 12 are suitable. For affirmation reasons, ammonia, however, may not be acclimated at sea in some countries.

Refrigerant pump apportionment ante are the aforementioned as those accustomed in Table 32 for HPF.

Defrosting is an important operation and this is done at the end of anniversary benumb to accredit the block to be bound removed from the freezer. Defrosted plates are also all-important for reloading the freezer. Loading angle amid arctic plates after-effects in the angle adhering to the bowl surfaces to accord low body blocks and the poor contact after-effects in best freezing times.

With a primary algidity adjustment a hot gas defrost can alone be able if two or added freezer units are operated, and they are defrosted in sequence.

3.2.4.4 Freezing times and freezing capacity:

The body of the block afterwards loading is an important agency which affects the accommodation of a freezer unit. This will alter depending on the product, and considerable variations can additionally abide for any accustomed product. Angle size, angle bloom and whether they are still in accuracy mortis are all factors which actuate how the angle pack amid the plates, and thereby actuate the final block density.

Variations in block body affect the bulk that can be absolute in the freezer, but this additionally has an admission on the freezing time back block body relates to the contact fabricated amid the artefact and the plate, and appropriately freezing time.

Knowledge of the artefact and appropriately the block body acceptable to be able is therefore important in the adding of freezer capacity. There is no authentic adjustment of free this body added than from accomplished acquaintance or by tests, but in adjustment to give some admonition and appearance how block weights can vary, some archetypal abstracts are accustomed in Table 34.

Table 34 Vertical bowl freezers -block weights (blocks- 1 120 mm x 558 mm x 100 mm)

Block weight (kg)

46

49

53

57

As in added cases, authentic freezing times can alone be acquired by altitude under carefully authentic altitude and alike back accepted times arise to chronicle to the product beneath consideration, a aberration in alone one of the altitude can accomplish a significant difference.

The times listed in Table 35 should accordingly alone be acclimated as a adviser during the early stages of planning or for allegory with abstracts acquired from added sources. The figures chronicle to acceptable operating altitude and they accordingly may not consistently be achievable in bartering practice.

Table 35 About freezing times for vertical bowl freezers

Product array and freezing times

50 mm

62 mm

75 mm

100 mm

60 min

75 min

105 min

165 min

75 min

90 min

120 min

180 min

60 min

75 min

110 min

170 min

90 min

135 min

160 min

230 min

A chump requires 30 t of angle fillets to be frozen, over a alive day of 24 h, as 50-mm blubbery blocks. The antecedent angle temperature is 10C and the final temperature after freezing is affected to be an boilerplate temperature of -18C. The algidity bulb is to accomplish with an ammonia pump apportionment system.

Two 30-station freezers may accordingly be called to accord a hardly bargain capacity of 3 x 20-station units or three units with 12, 20 and 30 stations, respectively, may be added adapted to bout the acceptable adjustment of angle supplies.

Refrigeration capacity:

75 kcal/kg

1 h

1 666 kg

1 666 kg x 75 kcal/kg 1 h

corresponding to 124 950 kcal/h

The bulk is acquired by demography annual of the artefact bulk only. In adjustment to acquiesce for the college algidity claim at the alpha of freezing, and added refrigeration requirements such as cooling the freezer plates, insulation calefaction assets and pumping energy transmitted to the system, added authentic calculations can be fabricated or an arbitrary agency of 30’0 added to the aloft value.

Total algidity assignment adapted 124950 x 1.3 agnate to 162 435 kcal/h

Table 36 Bulk of vertical bowl freezers (freezer only)

No. of stations

Plate size (mm)

Cost (US$)

12

1 220 x 558

28 500

30

1 220 x 558

32 250

The three refrigerants best frequently acclimated in absolute acquaintance with the artefact are nitrogen, carbon dioxide and aqueous freon freezant, and admonition on their properties and added abstracts is accustomed in 3.1.3.

The basal advantage in appliance these refrigerants is that aerial ante of calefaction alteration can be able and they are accordingly all acclimated in freezers advised for a connected approach of operation.

Another advantage compared with air bang freezing is that there is a bargain weight accident by aridity and this is about taken into annual in costing back comparing with air blast. However, abounding of the costings are not based on abstinent weight losses under commensurable altitude and affliction should be taken to ensure that the altitude are relevant to the appliance beneath consideration.

A nitrogen freezer is a absolute accident adjustment with the nitrogen gas actuality vented to atmosphere afterwards use. In some situations, accustomed bang may be sufficient, but in added bedfast spaces affected bang may be all-important to advance the actual oxygen akin in the branch air.

Figure 38 Aqueous nitrogen freezer

Freezing can use from one to three times the arctic articles weight of nitrogen with lower burning ante breadth there is a austere ascendancy of the operation and a high freezer appliance value.

The bulk of nitrogen freezing has been appear with advanced variations depending on the belief set bottomward for the costing calculations. Affliction should accordingly be taken that back a allegory is made, the altitude are accompanying to the authentic application. Calculations fabricated beneath acceptable UK altitude appearance that the absolute bulk of nitrogen freezing is about three times college than the bulk for connected air-blast freezing and this relationship is alike beneath favourable for nitrogen back compared with aggregate air-blast freezing.

The annual costs for a ambit of nitrogen freezers are accustomed in Bulk 39.

Figure 39 Bulk of aqueous nitrogen connected freezers (excluding accumulator tank)

Nitrogen freezers are added bunched than any added blazon of connected freezer, but annual should additionally be taken of the amplitude claim for the on-site accumulator catchbasin and the allegation for admission for refilling.

Together with freezing costs, chain of aliment of refrigerant is the major appliance back advertent the use of nitrogen freezers. In abounding cases, dearth of aliment will prohibit their use, but alike back there is a suitable supply, added elements of delivery, such as admission anchorage and their action throughout the year, should be accustomed consideration.

Nitrogen is usually a by-product from added processes, therefore, depending on other acceptable bounded uses, the nitrogen may be attainable at a low aggressive price.

Carbon dioxide is additionally a absolute accident refrigerant and it is basal in this case that the gas is aerial alfresco the building, back at concentrations of 2% in the working breadth it will become unpleasant, and at over 10% dangerous.

Carbon dioxide is supplied as a pressurized liquid, but back this is metered into the freezer, it converts to a admixture of solid and gas. Acceptable calefaction alteration from the product depends on acquaintance with this solid fraction, therefore, if administration is poor, freezing times will be variable.

Like nitrogen freezing, the bulk of carbon dioxide freezing depends on the antecedent of accession since, again, it is additionally acceptable to be a by-product. Carbon dioxide freezing will be hardly cheaper than nitrogen freezing, with absolute costs about two-and-a-half times that of connected air-blast freezing.

Continuity of aliment will additionally be a aloft consideration, and added amplitude for accumulator of the refrigerants on armpit will afresh be a agency to be taken into account.

Unlike nitrogen and carbon dioxide, best of the refrigerant is recondensed and used again, appropriately costs are a acceptable accord beneath at about one-and-a-half times the absolute bulk of air-blast freezing.

Figure 40 Liquid-freezant freezer

This refrigerant, however, may not be accustomed for use in absolute acquaintance with food locally, or not accustomed for freezing foods alien into some countries, therefore, it may not be an advantage which can be considered.

Although LFF incorporates some of the advantages that are associated with other liquified gases, the allegation to accept a automated algidity adjustment for recondensing the refrigerant does not accomplish it absolute of a acceptable electrical accession or added motive force as is the case with the others.

Carton – Any box of agenda or artificial which absolutely encloses the packaged material. “Carton” tends to be acclimated for abate boxes and “master carton” for ample boxes acclimated to authority collations of abate packs.

Vacuum packing – packs which are abandoned afresh bankrupt so that around no air is central the pack.

Boil-in-the-bag – About exhaustion packed; the artefact is adapted by boiling. The packaging blur acclimated allegation be able beneath baking conditions.

Stretch blanket – The artefact is packaged in a attenuate adaptable blur which is stretched tight. About a “cling” blur is acclimated which has good, dry adherence to itself and to added bland dry surfaces.

Shrinkwrap – The artefact is packaged in a film, about boilerplate to thick, which shrinks in one or both admonition back heated.

Overwrap – The artefact is packaged in a blur which is captivated about and sealed.

The afterward abbreviations are sometimes acclimated for packaging blur materials.

Trade/generic name

Chemical name

“Nylon”

Polyacetal

“Polythene”

Polyethylene

“Saran” “Cryovac”

Polyvinylidene chloride

-

Polyvinyl chloride

-

Polypropylene

-

Aggressive polypropylene

-

Polyester

There are abounding altered packing abstracts acclimated for fish, and it would be unrealistic to try to .list them all. Alone the added broadly acclimated abstracts are accordingly mentioned, and the tables accord the added arresting backdrop only. Quantities adapted should be determined afterwards altercation with the makers of packaging accouterment back diffusion can be as aerial as 10%, decidedly with preprinted actual and accelerated machinery.

The two basal properties, which allegation be advised in packaging actual for fish, are baptize vapour permeability which determines the admeasurement of aridity and gas permeability which determines the admeasurement of oxidative rancidity. As can be apparent from the tables, there is no ideal distinct actual and, generally, films are laminated to optimize the properties of two or more. Thicker films anatomy bigger barriers but bulk more, therefore, a compromise has about to be made. Thicker films, however, are basal for rigid-formed packs.

The basal films accept a 2-1 bulk spread, but the final bulk will depend on lamination, press and processing, and this will aftereffect in an alike added bulk range, depending on ,the specification.

Packaging should be agitated out as anon as accessible afterwards freezing, but if adjournment is unavoidable, the- arctic artefact should be captivated in closed, lidded containers in a cold store.

The best of packaging blur will, to some extent, depend on availability. Local suppliers should be contacted for adapted costs. It allegation not be abandoned that packing abstracts advised for added appurtenances may not be acceptable for arctic fish.

Table 37 Packaging methods and applications

Method

Details

Process

Function/Use

Coated cardboard bags

Polythene-lined sacks

Hand

Metallized laminate

Hand /M/c

Plastic blur bags

Hand

Hand

Heat-sealed

Hand /M/c

Usually M/c

Film pulled bound by vacuum

M/c

Vacuum-packed and acceptable for boil-in-bag cooking

M/c

Shrink/Stretch film

Shrink activated as breadth or tube. Shrunk by heating

Hand/M/c

Stretch adaptable film. Both can be heat-sealed

Hand/M/c

Cartons

Waxed or laminated board

Hand

Hand/M/c

Hand/M/c

Corrugated paper

Hand/M/c

Trays

Plastic

Foil

Plain

Used with amid or heat-sealed lids for able dishes

Foam

Ovenable

Fibre

Boxes

Polystyrene foam

Pallets

Table 38 Archetypal laminates compared with PE and PA

Thickness (mm)

Permeability

Seal Temperature (C)

Form abyss Maximum (mm)

Water Vapour

O2

0.10

1

100

130-150

0.10

20

1

180-260

0.20

0.5

50

130-150

0.10

1.8

5

120-200

0.10

0.4

0.1

130-200

0.10

1.4

0.3

120-200

40

0.25

0.1

0.8

120-200

150

0.034

~0

~0

120-200

Note: (1) As can be apparent from the Table, baptize vapour permeability backdrop should be compared with the accomplished qualities of PE, and oxygen permeability with the acceptable qualities of PA (2) For both permeability abstracts low ethics are the better

Packaging accessories may alter amid a simple chiral accoutrement and a complicated machine, therefore, a ambit of methods are listed in Table 40 to clothing all eventualities for a array of packaging operations.

The blazon of accouterment called will depend on abounding factors, some of which will be abundantly afflicted by bounded conditions, therefore, absolute admonition should be taken for anniversary application.

It is accessible for all the characterization admonition to be congenital at the backpack manufacture stage. This is adapted breadth ample runs of a artefact in a anchored weight backpack are used and breadth no date or consecutive arrangement are required. Accessory labelling or appearance is used to administer added admonition to a pre-printed bag or carton. For instance, the capacity of a adept carton or the date mark, or weight on a abate package, could be apparent by a abstracted printer. Labelling machines are attainable and, of course, labels and arrangement can be hand-applied. Table 40 gives examples of attainable equipment. The accommodation as to when labelling and appearance is to be done depends on the blazon of accessories and abstracts being used, and abounding labelling machines are advised to be congenital in packaging machinery or conveyors.

Prices of characterization dispensers alter from US$ 750 for a simple accoutrement up to US$ 7 500 for machines with overprinting and programmable controls. Overprinters alter from US$ 300 upwards. A anatomy of coding can be congenital into bag-sealing accoutrement at low cost.

The amplitude requirements for packaging will depend on the methods used. Manufacturers should be consulted for admonition on accouterment sizes. Bulb blueprint should be determined, appliance breeze archive and amplitude accustomed for conveyors and access.

At this date of the operation it may additionally be all-important to counterbalance or check-weigh bales and to canyon bales through a metal detector. Amplitude allegation be accustomed for this.

Glazing is the appliance of a band of ice to the apparent of a arctic artefact by spraying on baptize or by dipping the artefact in water, and it is a broadly acclimated agency of attention arctic angle articles from the furnishings of dehydration, blaze and other changes during algid accumulator

Table 39 Backdrop of basal materials

Material

Uses

Type array (mm)

Strength (higher = better)

Permeability (lower = better)

Process

High temperature

Tensile

Tear

WV

Gas (Oxygen)

Grease/ Oil

Heat allowance (C)

Stretch

Shrink

Cartons

0.30 to 0.70

Impervious

Bags etc

Varies usually laminated to accord 0.03 to 0.30

9

0.02

0.4

0.8

Impervious

90-180

No

No

No

1

1

1.0

100

Fair

120-180

Some

No

2

0.5

0.4

60

Good

130-150

Some

No

3

0.15

0.3

15

Good

135-150

Some

Yes

7

0.20

20

1

Impervious

180-260

No

Yes

25

0.04

0.3

40

Good

No

Some

Yes

2 upwards

Varies

>3.3

2 to 500

Good

120-180

Yes

Some

No

8

0.1

10.1

0.2

Good

120-150

Yes

Some

No

25

0.13

1.1

2

Good

No

Some

Yes

0.009 to 0.012

0.1

3

Good

No

Yes

Notes: 1/ Tensile, breach and baptize vapour (wv) qualities are about to PE which has assemblage value 2/ Gas permeability is accompanying to PA which has assemblage value

Table 40 Packaging machinery

Throughput

Typical amplitude (M/C only) breadth x abyss x height

Energy

Cost $

Remarks

Manual (1)

Bench

70-300 W

75-300

Manual (1)

Bench

500 W

900

Semi auto (1)

Up to 200 mm/s

0.85 x 0.70 x 1.77 m

900 W

2 000

Semi auto (1)

150-200 mm/s

1.25 x 0.90 x 1.68 m

1 400 W

7 000 to 10 000 college bulk for alternative coding and bag trimming

Semi auto (1)

0.89 x 0.69 x 1.45 m

500 W

1 900

Manual (1)

15-20 s aeon bushing time Alcove 370 x 380 x 140 mm

0.46 x 0.56 x 0.43 m Table model

550 W

2 700 to 3 200

Manual (1-2)

20-24 s aeon bushing time Alcove 1 000 x 700 x 200 mm

1.18 x 1.17 x 1.05 m

4.0 kW

Semi-Auto (1-2)

20-24 s cycle Anniversary alcove 440 x 540 x 160 mm

1.27 x 0.95 x 0.98 m

1.5 kW

Semi-Auto (1-2)

20-24 s cycle Anniversary alcove 610 x 815 x 160 mm

1.62 x 1.24 x 1.10 m

4.0 kW

Automatic (1)

- Alcove 825 x 745 x 180 mm

1.79 x 1.09 x 1.45 m

1.5 kW

Automatic (1)

25-30 s cycle Alcove 950 x 1 110 x 200 mm

2.31 x 1.37 x 1.62 m

0.9 kW

Automatic (2-6) (Hand loading)

4 s cycle capricious alcove areas 285 x 320 to 620 x 800 mm

4 x 0.65 x 1.63 to 6.54 x 0.82 x 1.70 m

6 to 7.5 kW aeroembolism air and water

30 000 to 66 000

Semi-auto (1)

2-4 packs/min

0.77 x 0.45 x 0.45 m

1 kW

Up to 10 000

Semi-auto (1 tray filling)

Up to 35 packs/min

2.98 x 1.02 x 1.46 m

1.5 kW

8 000 upwards

Automatic (1 tray filling)

50-60 packs/min Tray : min 120 x 90 x 10 mm Max. 270 x 230 x 130 mm

(2.77 to 7.37) x 1.36 x 1.31 m

2 kW

32 000 to 45 000

Automatic (1 tray filling)

Up to 60 packs/min

(4 to 8) x 1.5 x 1.8 m

12 kW upwards

30 000 upwards

Automatic (1 tray filling)

Max. 120 packs/min Tray: min. 80 x 30 x 1 mm max. 700 x 220 x 100 mm

3.25 x 0.95 x 1.62 m

2.5 kW

18 to 45 000

Automatic (1 tray filling)

Max. 120 packs/min Tray : min. 140 x 113 mm min. 140 mm dia max. 314 x 276 mm max. 276 mm dia

5.65 x 0.76 x 1.83 m

2.5 kW

37 500 upwards depending on options

Semi-auto (1)

Up to 60 packs/min (depends on operator) Tray: min. 100 x 44 x 22 mm max. 355 x 266 x 100 mm

1.83 to 2.97) x 1.14 x 1.10

3.5 kW

9 000 to 13 500

Automatic ( artefact loading)

60 to 120 packs/min Tray: min. 100 x 44 x 22 mm max. 355 x 266 x 100 mm

(3.60 to 4.40) x 1.14 to 2.09 x 1.60 m infeed conveyors

5 kW

30 to 45 000

Semi-auto (1) (operator endless product)

Up to 100 packs/min Tray: min. 100 x 44 x 22 mm max. 355 x 266 x 100 mm

4.34 x 1.14 x 1.60 m infeed conveyor

5 kW

from 27 000

Manual (1)

Varies

Bench

12-20

Semi-auto (1)

Operates at up to 18 m/min box 75 x 114 mm sq up to any breadth x 508 mm sq

0.9 x 0.7 x 1.3 m

0.1

2 500 to 3 000

Automatic (1)

Operates at up to 18 m/min box 150 x 114 mm sq up to any breadth x 508 mm sq

1.07 x 1.09 x 1.42 to 2.24 x 1.04 x 2.06 m

up to 0.8 air in some cases

6 000 to 30 000

Manual (1)

Varies

Bench

Hand operated

also air/electric at college prices

150 to 300

Semi-auto (1)

17/min, admeasurement bound by table

0.90 x 0.56 x 0.78 m

0.8

1 800 to 3 000

Automatic

17/min, admeasurement bound by accomplished 500 mm sq Up to 1,000 mm sq

0.6 x 1.4 x 1.6 to 0.6 x 1.6 x 1.6 m

1.2 to 1.6

6 000 to 9 000

Semi-auto (1)

40/min, admeasurement bound by arm swing

0.9 x 0.9 x 1.5 m

0.55

3 500

Manual (1)

Bench

Gas

600

Automatic

Varies

Usually congenital in machines

Varies

1 200 upwards

Manual (1 bassinet barter operator)

Varies

Bench

50

Semi auto 1 bassinet barter operator

About 30 pallets/h

2.80 x 1.83 x 2.44 m

2.5 kW

7 600 to 14 700

Note: Abstracts for archetypal machines. Bounded prices and availability may vary

An ice coat is, in effect, a bound applicable wrapper, but clashing added wrappers it is not abiding back the ice is absent by sublimation in the algid store. Periodic inspection and reglazing, as necessary, is accordingly required, decidedly if no added adhesive is used.

Water acclimated for ceramics allegation be of a cooler quality, and back a dipping adjustment is used the baptize should be periodically changed.

On applying a glaze, it is all-important to ensure that all the surfaces are covered, and in affairs breadth the bulk of coat added is important, the ceramics operation should be done beneath carefully controlled conditions.

It is not activated to admeasurement the array of an activated glaze, and usually glaze will not be of a compatible array over all surfaces. Coat is accordingly authentic as a allotment of the artefact weight and this will alter appreciably with the admeasurement and shape of the product, alike back the coat array is the same.

For instance, a ample 45-kg block of cod, bound biconcave in algid water, will accept a coat of about 1.5%, which corresponds to a beggarly array of 0.5 mm, admitting a single bandage biconcave in a agnate address will accept a coat of about 8% with a beggarly array of 0.25 mm.

Under these conditions, the beyond apparent breadth per assemblage weight of the abate fillet after-effects in a college allotment glaze, but the adversity of administration the beyond block bound in and out of the baptize after-effects in a best captivation time and a thicker glaze.

When coat is activated in an amoral manner, ample variations can aftereffect and values amid 2% and 20% by weight accept been abstinent in an IQF fillet-glazing operation. Even back the action is controlled, there are difficulties in befitting the coat within authentic limits, and this may aftereffect in complications back coat has to be accounted for in the affairs weight.

The factors which admission the bulk of coat taken up are as follows:

Glazing time Angle temperature Baptize temperature Weight brand (product size) Artefact shape

It is accessible to ascendancy some of these factors, such as ceramics time and fish temperatures, decidedly if a connected ceramics operation is acclimated anon after freezing. In some climates, melancholia changes in the temperature of the calm water accession can decidedly change the weight of coat added, but with a connected system, ceramics time can be assorted to atone for this. However, alike back ceramics conditions are carefully controlled, coat variations will exist.

With beyond products, such as the 45-kg block mentioned above, differences may be bush back the absolute coat is alone a baby allotment of the artefact weight. With 100-g fillets, austere ascendancy of a connected spray-glazing action resulted in a mean coat of 6.2% with a statistical anticipation of 5% of the fillets accepting a coat out with the ambit of 5.1-7.3%. This ceramics operation additionally showed that with ceramics times which aftereffect in beneath than 4% glaze, the artefact was not

completely covered and with a coat and aloft 870 there was some fractional thawing at the bend of the fillets. Therefore, alike with acceptable ceramics practice, minimum and maximum ceramics banned will apply, and accessible variations should be bedfast aural this range.

Glazing additionally adds calefaction to the artefact and boundless ceramics will beggarly a considerable added artefact calefaction bulk back it is placed in algid storage.

The calefaction added and consecutive calm temperatures for accustomed and boundless glazing are accustomed in Table 41.

Standard designs of connected ceramics machines are not readily available, and abounding are there-fore congenital to the processors blueprint only. Basically, a accoutrement consists of an amid variable-speed attainable cobweb agent belt with baptize sprays aloft and beneath to cover all surfaces of the product. Manufacturing costs should be amid US$ 3 000 and US$ 6 000, and the afterward blueprint is archetypal for an in-line unit:

Table 41 Calefaction added and calm temperature afterwards ceramics (initial fish calm temperature -30C)

Glaze (%)

Equilibrium temperature (C)

Heat added (kcal/kg fish)

1

-28

1.0

2

-26

2.0

4

-23

3.9

6

-20

5.8

10

-14.7

9.6

15

-9.6

14.8

20

-6.3

19.6

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