6. TREATMENT OF FISH AFTER FREEZING


6.1 Glazing
6.2 Packaging of frozen fish


As soon as fish are removed from a freezer, they should be glazed or wrapped (unless they have been packaged before freezing) and immediately transferred to a low temperature store. When it is known that storage will be for a short period only, glazing or wrapping may not be necessary or practical. Blocks of whole cod, frozen at sea, are usually transferred to the ship's cold store without a protective wrapper or glaze but this may be added later, prior to long term storage on shore. During relatively short terms of storage, fish without a protective wrapper or glaze can be severely dehydrated in a poorly designed or operated store.

6.1 Glazing

The application of a layer of ice to the surface of a frozen product by spraying, brushing on water or by dipping, is widely used to protect the product from the effects of dehydration and oxidation during cold storage. The ice layer sublimes rather than the fish below and it also excludes air from the surface of the fish and thereby reduces the rate of oxidation. Heat added by the glazing process is often considerable and the fish may require to be recooled in a freezer before being transferred to the cold store.

In order to form a complete and uniform glaze on the surface of the fish, the glazing process requires to be closely controlled. The amount of glaze applied depends on the following factors:

Glazing by dipping in a container of water is not recommended. The initial temperature of the water may be relatively high; this is reduced as glazing proceeds and the thickness of glaze will therefore vary. The glaze on IQF fillets has been shown to vary between 2 and 20 percent using this method, even when the immersion time was kept constant. In practice, the time will not be constant and this will give rise to even greater inconsistency. The water will also become contaminated after some time; therefore, this method is not recommended. If a dipping method is used to apply a glaze, the container should be continuously supplied with chilled water and fitted with an overflow.

Spray glazing methods are suitable, but again it is difficult to obtain a completely uniform glaze and it may be necessary to invert the fish to ensure that all surfaces are treated.

The glazer shown in Figure 26 has a number of features which enable a complete uniform glaze to be applied.

  1. A constant speed belt will ensure a fixed time in the glazing zone;

  2. The overhead and underside spray provide a constant supply of chilled make-up water and glazes both the upper and lower surface of the product;

  3. The double belt arrangement forces fish to invert providing an even glaze.

  4. The adjustable baffle may be used to rearrange overlapping fish on the belt so that each fish is totally exposed;

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Glazing when the fish surface temperature is at -70°C or lower, e.g. immediately after cryogenic freezing, results in a glaze which is fractured and broken due to thermal stress during the formation of the ice. This glaze is easily dislodged during subsequent handling. If the fish are immersed in the glaze water for too long, a thick glaze is formed but the equilibrium temperature of fish and ice is high and only slightly below 0°C. This glaze will be soft and easily dislodged during subsequent handling.

Good glazing practice can be beneficial, particularly when other aspects of storage and transport are far from ideal, but poor glazing involving partial thawing of the fish and slow refreezing in cold storage may do more harm than good.

6.2 Packaging of frozen fish

6.2.1 Need for Packaging

After fish has been frozen, it can be subjected to many forms of deterioration between production and eventual consumption. Contamination from humans, animals, insect and atmospheric sources is possible. Physical damage can be caused by bad handling during stacking, transit and storage or display in freezer cabinets. The sensory properties can be adversely affected by tainting and textural and flavour changes can be caused by dehydration and chemical changes which can take place under poor cold storage conditions. To prevent or reduce losses in product quality, it is essential that the frozen product is packaged in such a way as to provide an effective barrier with sufficient impact and compression strength to prevent mechanical damage. The packaging material must have adequate barrier properties to reduce losses due to dehydration and pick-up of taints. Further considerations are the printability of the material, so that a well designed attractive illustrated package can be produced. The package should give the consumer information on the nutritional properties of the product and instructions on how the product should be prepared, stored and give the 'use by' or 'best before' date.

A final consideration which is becoming increasingly important is the environmental issue. Considerations should include the impact of the packaging material on the environment, whether or not the package is re-usable or recyclable, whether the package is made from renewable resources and if the package produces pollution when it is being destroyed.

6.2.2 Types of Packaging Material for Frozen Fish

The range of packaging material for frozen fish is very wide and is dependant on the form of the product being packed. Whole fish frozen in a vertical plate freezer, for example, may require little packaging, other than an ice glaze, to prevent dehydration. Small pelagic fish frozen in vertical plate freezers may benefit from being frozen in water blocks where the freezer plate is lined with a robust plastic paper lined bag. This can be filled with water after the fish have been placed between the freezer plates. A processed fish product, for example fish sticks, may be wrapped in a primary package which is in direct contact with the frozen food and then stored in an outer carton. A number of primary packages may be collected together and packaged in a master carton (secondary package) for delivery or display in a freezer cabinet. The secondary packages can be bought together in a tertiary package, for example a wrapped pallet, and used for bulk transportation.

6.2.3 Primary Packaging Material

6.2.3.1 Plastics

The primary package in contact with the frozen product is generally a plastic derived from a natural hydrocarbon source. The choice of which plastic wrapper is dependant on the type of barrier required, and if the product is to be cooked or heated in the container. Migration of the plasticisers from the wrapping is a potential health hazard and the type of wrapping which can be in contact with food is covered by national legislation. The non-biodegradability of plastic wrapping material is an environmental issue and toxic compounds eg dioxins can be produced when, for example polyvinylidene chloride (PVDC) or polyvinyl chloride (PVC) plastics are incinerated at low temperatures.

Many different types of packaging materials are used for fish, and it would be unrealistic to try to list them all. Tables 10 and 11 list various films and laminates, their barrier properties and Table 12 lists various packaging methods and their applications . Table 13 summarises the properties of the basic material in comparison with nylon and (Polyacetol, PA) and polythene (Polyethylene, PE), and Table 14 summarises the properties of laminate with polyethylene and nylon. Plastics with good moisture vapour barriers and stability at low temperatures are required for the storage of frozen fish, and a good vapour barrier is required to prevent oxidation of fats in frozen fatty fish. The group of plastics called polyolefins, which include polyethylene, polypropylene and its co-polymers are most widely used. Generally, the higher the density of the polyethylene the better the barrier properties, with polypropylene being the best. Polypropylene is able to withstand temperatures up to around 100°C and is therefore suitable for boil in the bag products. To package ovenable products, a modified polyethylene CPET (Crystaline Polyethylene Tetraphthalate) is used, which maintains low temperature flexibility.

Polypropylene or polyethylene laminated with polyamide or polyester are frequently used for boil in the bag type products, and laminated plastic aluminium foil may be used when good vapour and moisture barriers are required, particularly with fatty fish to prevent fatty acid oxidation.

Plastic and paper based packaging is transparent to microwaves (passive packaging) and therefore can be used to contain foods which are to be microwaved. Thin polyester films can be metalised with aluminium and then laminated to a supporting board. When microwaved the aluminium absorbs a certain amount of radiation, generating heat and cooking the product.

Other considerations concerning primary packaging materials are the sealability of the material by heat and also its printability properties.

6.2.3.2 Cartons

Cartons can also be regarded as primary packages when used as a protective sleeve to the product. The boards for the cartons can be made of :

  1. Kraft boards. These are frequently used for packaging frozen foods and are usually made from fully bleached materials. They are strong, of good appearance and are suitable for direct contact with food.

  2. Folding box boards. These usually have one fully bleached side which is suitable for direct contact with food.

  3. Recycled fibre boards. These are usually used for secondary and tertiary packaging.

6.2.4 Secondary Packaging

Secondary packaging is usually a carton which holds a number of primary packages. The secondary package is usually made from boards but can be bands of paper or plastic.

6.2.5 Tertiary Packaging

Tertiary packaging is used to hold a number of secondary packages. Tertiary packaging may be palletised for easy handling and wrapped with shrink, stretch wrap or corrugated outers or may be packed in re-usable containers. Wooden pallets are in regular use, but can become a source of contamination. Plastic pallets, which can be colour coded, are more easily cleaned but will support the growth of mould in frozen fish factories.

6.2.6 Packaging Machinery

Packaging equipment may vary between a simple hand operated tool to an extremely complex machine and examples are listed in Table 15. For primary packaging of frozen fish two types of carbon, top load and end loads are generally used.

6.2.6.1 Top Load Cartons

Top load cartons (Fig 27) which are formed immediately prior to packaging, are supplied flat and unglued. The cartons are erected by a machine at speeds of between 20 and 320 cartons per minute and glued with hot melt adhesives which can tolerate cold store conditions. Top load cartons are used for some forms of fish sticks, the product being loaded in through the widest opening. A top load processing line normally consists of three machines for carton erecting, filling and closing respectively. Closing is usually effected by heat seal or adhesive to make the container tamper proof.

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6.2.6.2 End Load Machines

End load cartons (Fig 28) are used for products which are sufficiently robust to allow the product to be pushed in at the end of the carton. These are frequently used as a primary package for frozen fish portions or fish sticks. The process is slightly more expensive than top load processing, but has the advantage that the process is carried out by a single machine.

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6.2.6.3 Auto Loading

Many machines have intelligent product - transfer units (IPTU's) which will automatically monitor and load the frozen product into the container and can be set to accept different tolerances. This technology is widely used in packaging frozen fish products to ensure that the weight of the product within the packet is with the designated tolerance.

6.2.6.4 Bags

Frozen fillets can be packed directly into bags made from materials with good gas vapour and moisture barrier properties. The level of sophistication can range from manual weighing and loading to a highly sophisticated form-fill-seal technology where a specified weight, volume or count of product is filled into a formed bag which is heat sealed. Such equipment can be used for packing IQF cooked, peeled shrimp.

6.2.6.5 In-Line Pouch Forming Equipment

In-line pouch forming equipment was developed in the mid 1960s to reduce the labour required to product the package, fill and seal the container. Such machines (Figure 29) are widely used in the frozen fish industry, particularly in situations where sauces are added to the product. The material for the package is formed from a roll of packaging laminate (bottom web) which is heat formed in a dye, either by compressed air or vacuum to form the pouch. The product is then loaded, either by machine or hand into the pouch and any added liquid will be added by an automatic depositor. The package then has the top sealing web brought into contact with the bottom web, evacuated and then heat sealed. Some products may have an inert gas injected into the package as an alternative to evacuation, to prevent the packaging coming into contact with the product. The packages are then separated by cutters which cut both along and across the webs which join the packages together.

Typical films for this type of packages are:

Bottom web - nylon 75 microns + polyethylene 50 microns = 125 microns

Top web - nylon 20 microns + polyethylene 50 microns = 75 microns

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6.2.7 Machinery For Tertiary Wrapping

Tertiary packaging is the final stage of the packaging procedures and machinery is available which will collate, package and palletise the secondary packages. Tertiary packaging normally takes place after the product has been frozen. A typical operation would involve the orientation and collation of a number of secondary packages which would be automatically loosely wrapped in shrink wrap. The shrink wrap would then be heat sealed before the wrap packs are conveyed through a heated tunnel, where the wrapping shrinks to assume the geometry of the pack. Alternatively, the secondary packages can be packaged in cases, which may be formed round the product (wrap around) or the case may be preformed and glued before the packages are loaded.

The tertiary packs are then frequently palletised for storage or distribution. The pallet and contents themselves may be wrapped in stretch wrap or similar materials for further protection. This may be done by hand, but is increasingly carried out by mechanical pallet wrappers.

Table 10 Characteristics of some film used for the packaging of solid foods

 

Gas transmission cm3 m-2 day -1(dry gas)

Water vapour transmission g m-2 day - 1

Film (thickness 25 mm )

Oxygen
(at 23 °C)

Carbon dioxide
(at 23 °C)

Nitrogen
(at 23 °C)

RH 90.0%
(at 38 °C)

RH 90.0%
(at 25 °C)

LPDE (0.917)

7400.00

40000.00

2800.00

12.50

4.00

HDPE (0.960)

1600.00

11400.00

440.00

3.70

1.45

PP cast

3040.00

9760.00

690.00

8.20

3.30

OPP coextruded

1550.00

5280.00

320.00

5.00

1.35

OPP coated

15.00

88.55

4.50

5.00

2.00

OPP acrylic coated

1200.00

4500.00

250.00

4.60

1.80

OPP metallized

35.00

108.00

6.50

1.00

 

PVC rigid

120.00

320.00

20.00

32.00

12.00

PVC oriented

27.00

68.00

20.00

17.50

7.00

PVC plasticized

190-3100

430-19000

53-810

85.00

32.70

PVDC

1.25-14.5

5.0-50.0

0.4-2.5

0.6-3.20

0.25

PS cast

4500.00

11000.00

640.00

170.00

70.00

SAN

900.00

2800.00

120.00

 

 

Polycarbonate

3200.00

17500.00

450.00

178.00

72.50

PET

55.00

240.00

12.40

20.00

7.00

PET PVDC coated

8.00

32.00

2.00

8.50

3.40

PET metallized

0.65

3.4 -10.0

0.20

1.00

0.40

PA6

40.00

200.00

 

280.00

80-110.00

OPA 6

18.00

120.00

9.00

130.00

28.30

PA 6.6

35.00

140.00

11.00

90.00

15.0-30.0

EVAL (32% ethhylene)

0.16

0.45

 

80.00

32.00

Cellulosic film 445MXXT A

8.75

80.00

3.65

8.60

3.40

LDPE, low-density polyethylene; HDPE, high density polyethylene; PP, polypropylene; OPP, oriented polypropylene; PVC, polyvinyl chloride; PVDC, polyvinylidene chloride; PS. polystyrene; SAN, styreneacrylonitrile; PET, polyester; PA, polyamide; OPA, oriented polyamide; EVAL, ethylene-vinyl alcohol; MXXT, a PVDC coating.

Table 11 Characteristics of some laminates used for the packaging of solid foods

 

Gas transmission cm3 m-2 day - 1 (dry gas)

Water vapour transmission g m-2 day -1

Laminate

Oxygen
(at 23 °C)

Carbon dioxide
(at 23 °C)

Nitrogen
(at 23 °C)

RH 90.0%
(at 38 °C)

RH 90.0%
(at 25 °C)

Cellulose film 280XS +PE 40m

12.00

   

4.50

1.10

OPP coextruded 25m +OP coextruded 25m

650.00

   

2.60

0.95

PET coated PVDC 12m PE 40m

5.00

15.00

1.00

3.70

1.40

M PET 12m + PE 80m

1.00

4.00

0.20

0.50

0.20

M PET 12m + M PET 12+ PE80m

< 0.10

< 0.10

0.00

0.15

0.06

OPA 15m end. PVDC +PE 60m

10.00

30.00

2.50

5.00

 

OPA 6 20m + PE 80m

40.30

       

M OPA 5 15m + PE 80m

2.00

   

2.50

 

Kraft 45 g m-2 + PE 20 g

         

m-2

34.00

   

1.70

0.60

+ end. PVDC 20 g m-2

         

Kraft 60 g m-2 + end.

         

PVDC 30 g m-2

15.00

   

1.90

0.65

PET 12 m + 119 m+

         

monomer 20m

< 0. 20

   

< 0.10

 

Cellulosic film 320 DM

         

+A 19m + PE 35m

7.25

   

0.15

0.10

Kraft 70 g m-2 + PE 15 g

         

m-2

4.30

   

0.10

0.08

+ A 19 m

         

A 19 m + Kraft 70 g m-2

25.40

   

0.25

0.15

A 19m + TPP 20 g m-2

28.00

   

0.40

0.15

wax

         

30 g m-2 TPP 20g m-2

< 8. 00

< 35.00

< 3. 00

   

M, Metallized; Kraft, paper; DM. one side nitrocellulose coated; A, aluminium foil; TPP, this porous paper; XS. cellulosic film coated with PVDC

Table 12 Packaging methods and applications

Method

Details

Process

Function/use

Coated paper bags

Polythene-lined sacks

Hand

Water-filled blocks 20-50 kg, whole fatty fish

"

Metalized Laminate

Hand/M/c

Bulk pack - fish sticks, etc., (2.5 kg) reclose by folding

Plastic film bags

Polythene - laminated (preferable) generally transparent-somentimes over printed- can be metalized or opaque

Hand

Whole fish blocks 20 - 50 kg.
Can be unstable unless friction film used. Cover for pallet of blocks or boxes

"

Heat-sealed

Hand/M/c

Bulk packs (up to 2 kg) of IQF products

"

 

Usually M/c

Outer seal on small cartons

"

Film pulled tight by vacuum

M/c

IQF fillets, etc good appearance

"

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

M/c

IQF-smoked fish. Fish-in-sauce and prepared dishes

Shrink/stretch film

Shrink applied as sheet or tube. Shrunk by heating

Hand/M/c

(a) Used to stabilise and cover pallets

     

(b) IQF portions, enrobed products with tray (where enrobing might damage vacuum pack film)

 

Stretch elastic film. Both can be heat sealed

Hand/M/c

as (b) above

Cartons

Waxed or laminated board

Hand

For fillet blocks

   

Hand/M/c

For IQF products

   

Hand/M/c

Outer cover for products in film bags

 

Corrugated paper

Hand/M/c

Master cartons for smaller packages

Trays

   

Used with shrink or stretch film for IQF products

Used with inserted or heat-sealed lids for prepared dishes

 

Plastic Foil

 

Plain

 

Foam

 

Overnable

Boxes

Polystyrene foam

 

Used as an outer cover for packs of whole shellfish, e.g. Nephrops

Pallets (Not strictly packaging, but used as the basis for collection of blocks and cartons in to tertiary packaging)

Table 13 Properties of basic materials

     

Strength
(higher = better)

Permeability
(lower = better)

Process

 

Material

Uses

Type thickness (mm)

Tensile

Tear

WV

Gas (Oxygen)

Grease/Oil

Heat seal (C)

Stretch

Shrink

High temperature

Waxed or polycoated

Cartons

0.30 to 0.70

-

-

-

-

Impervious

-

     

White bleached board or chip board

                     

Cellophane

Bags etc

 

9

0.02

0.4

0.8

Impervious

90-180

No

No

No

Polythene (PE) low density

"

 

1

1

1.0

100

Fair

120-180

 

Some

No

Polythene medium density

"

 

2

0.5

0.4

60

Good

130-150

 

Some

No

Polythene high density

"

varies usually

3

0.15

0.3

15

Good

135-150

 

Some

Yes

Nylon (PA)

"

laminated to give 0.03 to 0.30

7

0.20

20

1

Impervious

180-260

 

No

Yes

Polypropylene (PP) (oriented')

"

 

25

0.04

0.3

40

Good

No

 

Some

Yes

PVC

"

 

2 upwards

Varies

> 3.3

2 to 500

Good

120-180

Yes

Some

No

PVdC (Saran)

"

 

8

0.1

0.1

0.2

Good

120-150

Yes

Some

No

Polyester (PET)

"

 

25

1.13

1.13

2

Good

No

 

Some

No

Aluminium Foil

"

0.009 to 0.012

-

-

0.1

3

Good

No

   

Yes

Notes: 1. Tensile, tear and water vapour (WV) qualities are relative to PE which has unit value

2. Gas permeability is related to PA which has unit value

Table 14 Typical laminates compared with PE (Polyethylene) and PA (Nylon)

 

Thickness

Permeability

Seal Temperature

Form depth Maximum

Material (mm)

(mm)

Water Vapour

O2

(°C)

(mm)

PE

0.10

1

100

130-150

 

PA

0.10

20

1

180-260

 

PE

0.20

0.5

50

130-150

 

PA/PE 30/70

0.10

1.8

5

120-200

 

PE/PVdC/PE

0.10

0.4

0.1

130-200

 

PA/PVdC/PE

0.10

1.4

0.3

120-200

40

PA/PVdC/PE

0.25

0.8

0.1

120-200

150

Alum foil/PE 16/84

0.034

0

0

120-200

 

Table 15 Packaging machinery

Method

Manpower

Throughput

Typical space
(M/C only)
Length × depth × height

Energy Cost $ Remarks

Heat sealing

Manual (1)

-

Bench

70-300W

75-300

Static. Intermittent use

 

Manual (1)

-

Bench

500W

900

Rotary Band. 5-h day

 

Semi Auto (1)

Up to 200 mm/s

0.85 × 0/70 × 1.77 m

900W

2000

Rotary Band. 12-h day

 

Semi Auto (1)

150/200 mm/s

1.25 × 0.90 × 1.68 m

1400W

7000 to 10000
Higher price for optional coding and bag trimming

Rotary Band. Continuous

 

Semi Auto (1)

-

0.89 × 0.69 × 1.45 m

500W

1900

'L' sealer for film

Vacuum packing bag fed

Manual (1)

15-20 s cycle + filling time Chamber 370 × 380 × 140 mm

0.46 × 0.56 x 0.43 m
Table model

550W

2700 to 3200

'L' sealer for film
 

Manual (1-2)

20-24 s cycle + filling time Chamber 1000 × 700 × 200 mm

1.18 × 1.17 × 1.05 m

4.0W

 

Single chamber machines

 

Semi auto (1-2)

20-24 s cycle
Each chamber 440 × 540 × 160 mm,

1.27 × 0.95 × 0.98 m

1.5kW

   
 

Semi auto (1-2)

20-24 s cycle
Each chamber 610 × 815 × 160 mm

1.62 × 1.24 × 1.10 m

4.0 kW

 

Twin chamber machines

 

Automatic (1)

-
Chamber 825 × 745 × 180 mm

1.79 × 1.09 × 1.45 m

1.5 kW

   
 

Automatic (1)

25-30 s cycle
Chamber 950 × 1110 × 200 mm

2.31 × 1.37 × 2.62 m

0.9 kW

 

Belt loaded machines

Vacuum packing reel fed

Automatic (2-6)
(hand loading)

4 s cycle
Varying chamber areas
285 x 320 x to 620 x 800 mm

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

6 to 7.5 kW + compressed air and water

30000 to 66000

 

Tray scaled lid

Semi Auto (1)

2-4 packs/min

0.77 x 0.45 x 0.45 m

1 kW

Up to 10000

 

Tray stretch wrap

Semi Auto (1 + tray filling)

Up to 35 packs/min

2.98 x 1.02 x 1.46 m

1.5 kW

8000 upwards

 
 

Automatic (1 + tray filling)

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

(2.77 to 7.37) ×1.36 × 1.31 m

2 kW

32000 to 45000

 

Tray shrink wrap

Automatic (1 + tray filling)

Up to 60 packs/min

(4 to 8) × 1.5 × 1.8 m

12 kW upwards

30000 upwards

 

Tray overwrap Automatic
(1 + tray filling)

 

max. 120 packs/min
Tray min. 80 × 30 × 1 mm
max. 700 × 220 × 100 mm

3.25 × 0.95 × 1.62 m

2.5 kW

18 to 45000

 

Foil tray lidder

Automatic ( 1 + tray filling)

Max. 120 packs/min

5.65 × 0.76 × 1.83 m

2.5 kW

37500 upwards depending on options

 

Carton scaling

Semi Auto (1)

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

(1,83 to 2.97) × 1.14 × 1.10

3.5 kW

9000 to 13500

operator forms cartons

Carton forming

Automatic ( + product loading)

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

(3.60 to 4.40) × 1. 14 to 2.09 × 1.60 m + infeed conveyors

5 kW

30 to 45000

 
 

Semi Auto (1) (operator loads product)

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

4.34 × 1.14 × 1.60 m + infeed conveyor

5 kW

from 27000

 

Master carton taping

Manual (1)

Varies

Bench

-

12-20

 
 

Semi Auto (1)

Operates at up to 18 m/min
Box 75 × 115 mm sq up to any length × 508 mm sq

0.9 × 0.7 × 1.3 m

0.1

2500 to 3000

 
 

Automatic (1)

Operates at up to 18 m/min box 150 × 114 mm sq up to any length × 508 mm sq

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

Up to 0.8 + air in some cases

6000 to 30000

 

Master carton strapping - polypropylene straps

Manual (1)

Varies

Bench

Hand operated

Also air/ electric at higher prices 0.8

150 to 300

Strap fed by hand

 

Semi Auto (1)

17/min, size limited by table

0.90 × 0.56 × 0.78 m

 

1800 to 3000

Box on table

 

Automatic

17/min, size limited by arch
500 mm sq up to 1000 mm sq

0.6 × 1.4 × 1.6 to 0.6 × 1.6 × 1.6 m

1.2 to 1.6

6000 to 9000

Box passes through arch

Master carton string tying

Semi Auto (1)

40/min, size limited by arm swing

0.9 × 0.9 × 1.15 m

0.55

3500

 

Heat shrinking

Manual (1)

-

Bench

Gas

600

Hand held shrink gun

Heat shrinking

Automatic

Varies

Usually incorporated in machines

Varies

1200 upwards

 

Stretch wrap

Manual (1 + pallet truck operator)

Varies

Bench

-

50

Dispenser for 400-mm wide film

 

Semi Auto 1 + pallet truck operator

About 30 pallets/h

2.80 × 1.83 × 2.44 m

2.5 kW

7600 to 14700

 

Note: Data for typical machines. Local prices and availability may vary.