5.1 General Canning Equipment
5.2 Equipment for Canning Tuna
5.3 Equipment for Canning Sardines
5.4 Equipment for Canning Fish Paste Products

Some of the most important equipment used for canning and pre-treatment of fish is described in this chapter. The items selected are chosen, more to give an impression of the processing principles, rather than to recommend particular equipment.

5.1 General Canning Equipment

5.1.1 Retorts

As briefly described previously retorts are used to sterilize the contents of the cans.

Horizontal retorts, which are commun within the fish canning industry, have the following general features :

The major components of such retorts are the retort shell (body), crates and various controllers.

The capacity of the retort is .optional and depends on the output of the cannery, however as a guide a retort which holds 1 400 cans (850 ml) per batch would suit most medium sized batch operations. In this case the retort would be approximately 4 000 mm long and have a diameter of 1 200 mm. The size of each crate would be 800 mm x 700 mm x 700 mm.

Approximate steam consumption would be 400 kg per batch while water consumption during cooling would be approximately 10 000 l per batch. Consumption of electricity would be approximately 5 kWh per hour for circulation pump etc.

Stainless steells mainly used in the construction of retorts.

Normally the retort can be operated by one person, who in many cases is in charge of a batch of retorts.

5.1.2 Seaming machines

There are several automatic seaming machines specially designed for closing filled square, oval and round aluminium or tin plate cans. Characteristics of a common machine are shown in Figure 22.

Automatic machines are fitted with can end and can body feeding devices and also with equipment for automatic code marking of can ends.

In addition they may also be linked with the following devices:

Automatic filling device

The device is designed for filling of oil, tomato sauce and other liquid sauces into cans. It is pneumatically operated and fills precisely measured quantities into each can.

Lidplunger and control closing device

The device is mounted on the closing machine and is particularly useful for overpacked cans. It presses the lid down on the can, and if the lid is not lying on the can, the seaming operation is automatically stopped.

Automatic seaming machines can operate at speeds of 3 500-4 000 cans per hour. Diateters of cans that may be seamed range from approximately 50 to 195 mm. The height of the cans may range from 15 to 120 mm. Multiple code markings are available.

Approximate length of the seaming machine will be 2 000 mm while width will be 2 000 mm .

Figure 22 Automatic seaming machine

Approximate consumption of electricity is 30-35 kWh per 8 hours.

The machine can be operated by two workers.

5.1.3 Can washing and drying machine

Can washing and drying machines are used to clean cans after sterilization in order to remove residual oils that may have adhered to the can surfaces during filling and retorting.

These machines are frequently fitted with a variable speed drive to regulate the speed of the conveyor-belt.

Approximate dimensions of these machines are 3 600 mm (length), 1 500 mm (height) and 1 600 mm (width).

The drive motors will consume approximately 60-70 kWh per 8 hours when fully used. If steam battery is used for heating it will consume approximately 200 kg steam per hour. If the machine is heated by electricity it will consume approximately 100 kWh per 8 hours.

All parts are made from stainless steel.

The machine is automatic, but may be fed by one or two workers. See Figure 23.

5.1.4 Cartoning machine

Cartoning machines are used for packing cans into individual cartons. The main characteristics of an air operated cartoning machines are given below.

Figure 23 Can washing and drying machine

They may be equipped with a rotating infeed table. The cartons are separated and opened by use of vacuum and the machine is equipped with a pump for this purpose. The machine has two electric motors each of 0.25 hp.

The capacity of the machine shown in Figure 24 is up to 65 cans per minute

Table 14 Dimensions of cans that may be operated by the cartoning machine, shown in Figure 24

Length: 85-180 mm
Width: 50-100 mm
Height: 12- 40 mm

Length of the machine is 2 400 mm and width is 800 mm

The motors will consume approximately 3-5 kWh per 8 hours. Consumption of compressed air is 160-200 litres per minute.

The machine may be fully automatic or it may be fed by one or two workers.

There are on the market other types of cartoning machines with capacity 120 or more cans per minute.

5.2 Equipment for Canning Tuna

5.2.1 Racks

Racks are used in the pre-cooking process. Baskets with tuna are placed on the racks before they are loaded into the cooker.

The main characteristics of racks used for tuna are given in the following:

A: Feeding conveyor for product
B: Cardboard boxes stack and extraction
C: Infeed attachment for product
D: Closing station for boxes
E: Discharge of finished cardboard boxes

Figure 24 Automatic cartoning machine

5.2.2 Baskets for cooking tuna

Baskets filled with tuna are placed in racks and loaded into the cooker.

The main characteristics of baskets often used for pre-cooking tuna are given below:

5.2.3 High speed tuna filler

A high speed tuna filler is a fully automatic machine designed to cut and fill pre-cooked tuna meat into round and/or oval cans.

The main components are the feeding unit, the cutting unit and the filling unit.

The machine fills tuna tablets ranging from 100 g to 1 kg. Mass speeds are shown in Table 15.

Length of the machine is 3 600 mm, width is 1 700 mm and height is 1 250 mm.

Table 15 Summary of operating parameters for automatic filling of round and oval tuna cans

Can description

Can dimensions

Fish tablet diameter

Filling speed






Standard round

60 to 90

24 to 45



up to 150

Large round

80 to 110

48 to 106



up to 70


65 x 105

20 to 40



up to 100

All contact parts are made from stainless steel.

Only one person is required to feed tuna loins into the machine.

5.2.4 Exhaust box

Exhaust boxes are used for heating cans to ensure that when sealed and cooled a vacuum is produced in the container.

The main characteristics for a typical exhaust boxes used for tuna are given in the following:

5.3 Equipment for Canning Sardines

5.3.1 Grading machines

The machine is designed to automatically grade sardines into various sizes.

The main characteristics of a typical grading machine for sardines are given below:

Figure 25 Grading machine for sardines

5.3.2 Brining unit

The main characteristics of an automatic brining unit. used for sardines are described below and shown in Figure 26.

5.3.3 Nobbing machine

A nobbing machine as described previously and illustrated in Figure 27 is used for head cutting, nobbing (which means pulling the viscera out of the belly), cleaning and tail cutting and/or fixed body cutting.

The characteristics of a nobbing machine used for sardines and herring are given below.

Figure 26 Brining unit

Figure 27 Cutting and nobbing machine

5.3.4 Continuous flash cooker

The flash cooker is used for pre-cooking and drying of sardines before exhausting and closing the cans.

The main components of the cooker shown in Figure 28 are the automatic charge and discharge section, the steam chamber, the draining section and the drying section. Two chains carry approximately 800 crates in which the cans are placed.

Chain speed and thereby cooking time is variable. Different types of cans can be cooked without adjustments to the cooker. Up to 12 500 club cans per hour can be processed.

Approximate dimensions are length 15 500 mm, width 1 600 mm and height 3 900 mm.

The cooker will require approximately 50-60 kWh per 8 hours if it is used fully while depending on load steam consumption is approximately 500 kg per hour.

The cooker is mainly constructed from stainless steel.

Being fully automatic one operator is required to supervise the machine.

5.3.5 Smoking kiln

The smoking kiln is also used for drying, pre-cooking and smoking sardines. The main components of a kiln are the drying unit, the smoking chamber, the fans, the heat exchanger and two motors, a 4-hp motor for the fans and a 1.5-hp motor for the chains.

The capacity of the automatic kiln shown in Figure 29 is 6 000-8 000 kg per 8 hours.

Approximate dimensions are length 11 650 mm, width 2 200 mm and height 2 170 mm.

The kiln requires approximately 30-40 kWh per 8 hours and consumption of oil is approximately 5 litres per hour.

Material used in construction is mainly black iron. Being fully automatic the kiln is operated by one worker.

5.4 Equipment for Canning Fish Paste Products

5.4.1 Meat separator

Fish meat separators are used to recover meat from split and washed fish.

The main components of a separator are normally a rotating perforated drum/cylinder, mounted horizontally, and a rubber belt. The perforated drum and the rubber belt rotates in the same direction, and the fish is squeezed in between the rubber-belt and the drum. The separator is equipped with a 5 hp motor.

The capacity is 10 tons washed and split fish per 8 hours, with an approximate yield of 7 tons minced fish and 3 tons offal.

Approximate dimensions of a typical separator are 1 060 mm x 1 127 mm x 1 050 mm.

The diameter of the holes in drum are 2 1/2- 3 mm.

The motor will require approximately 30 kWh per 8 hours.

All contact parts are made from stainless steel.

The machine is operated by one worker.

Figure 28 Flash cooker

Figure 29 Smoking kiln

5.4.2 Bowl chopper/mincer

The ingredients (fish, salt, milk starch, etc.) must be mixed and finely minced. The mincer-bowl rotates, and the ingredients have to pass under vertical high speed cutting knives.

The main components of the machine are the bowl, the mincer and a 50-100 hp motor.

Mincer/cutter capacities vary from approximately 25 litres to several hundred litres. The bowl capacity is approximately 325 litres.

Approximate dimensions of the chopper/mincer are (2 200 mm x 1 800 mm x 1 350 mm)

The motor will consume from approximately 300 to 600 kWh per 8 hours.

All contact parts are made from stainless steel.

The machine is operated by one worker.

5.4.3 Pumps for minced materials

The mixture of fish and ingredients is emptied from the bowl mincer into a container with a built-in screw and pump at its base. From this container the mass can be pumped, either to the ball former, or the fish cake former. The fish balls and cakes are extended through stainless steel pipes.

The main components are the container, the pump with a 2 hp motor and the pipes.

Approximate capacity is 40-50 litres per minute, with variable speed.

The dimensions are 1 550 mm x 1 100 mm.

The motor will require approximately 12 kWh per 8 hours.

All contact parts are made from stainless steel.

One operator is required.

5.4.4 Cooking equipment for fish balls

The cooker for fish balls may vary in size however an example of a cooker with a 2 000 kg/h capacity is given below.

5.4.5 Fryer for fish cakes

As the cakes have to be fried on both sides, they have either to be turned manually otherwise the machine can do this automatically.

A description of an electrical fryer for fish cakes is given below and shown in Figure 30.

Figure 30 Frying machine with fish cake former