Defrosting machines for high quality production

3X Technology manufactures a range of processing solutions for the white fish, salmon, shrimp, and pelagic fish sectors. Founded in 1994 the company has developed from supplying the local processing industry on Iceland to selling its equipment on the international market, earning it awards for its export performance.

Among the equipment the company produces is a solution for defrosting frozen fish. While there are several technologies that are used for the thawing process 3X Technology uses one that circulates temperature controlled water round the frozen product to thaw it gently and evenly. The system is used to thaw frozen blocks of herring, mackerel, shellfish, and whitefish and is based on the fact that the operator can control the heat supplied to the system, and the time the blocks are kept in the tank depending on the requirements. It uses the “first in, first out” principle to ensure that all the blocks are treated exactly the same way.

Feeding the frozen blocks into the thawing unit

Adjustable system caters to any requirement

The system comprises a tank with a large screw that effectively divides the tank into sections. An electronic conveyor saves labour by carrying the pallets with the blocks up to a scissor elevator at the in-feed end of the tank. The operator can adjust the height of the elevator so that he can comfortably remove the blocks from the pallet and feed them into the tank. Normally a single operator is enough to run the system at full capacity. Usually the tank is filled in the morning with water, the temperature of which is determined by the species that is being defrosted, how it is going to be used afterwards, as well as the product form. Apart from blocks the system can also thaw individually frozen items. The temperature of the water falls from one end of the tank to the other. For cod or other ground fish, for example, the water is typically between 9 and 11 degrees centigrade at the start – it should not be too hot – and by the time it reaches the outlet at the opposite end of the tank it will have dropped by 2 degrees. With whitefish, for example, by the time the fish is ready to come out of the defroster the temperature on the surface is 3 to 4 degrees while the core is between–0.5 and –1.5 degrees. At this stage the company recommends laying the fish in tubs for the final adjustment to the temperature, as filleting and skinning with a skin temperature of 4 degrees will reduce the yield.


Water recirculation is the future

To reduce water consumption the water is reused during the day. The system uses 20 percent of the water used in a conventional defrosting tank where the product is immersed and left to thaw for 10-20 hours. In the 3X Technology system the water from the outlet is filtered to remove any fish particles or other debris, it is reheated using steam or heat exchangers that can use several types of external energy, and is then pumped back into the tank. Fresh water is used each day, however the future, says Pall Kristjansson, marketing manager, is to add on recirculation equipment similar to that used on fish farms to recycle the water so that it can be used repeatedly for extended time periods without having to change it. The company is currently working on how to enable this.


Reduced labour costs as well as water saving

The defrosting system has a number of advantages, it offers better handling of the material, constant flow, water savings, reduction in labour costs, and better raw material yield in the fish produced afterwards, and is flexible with the possibility to control temperature and time. In addition the “first in, first out” principle ensures all the raw material gets exactly the same treatment. As the blocks move through the machine it is also possible to blow air on to them to prevent them from freezing together. The equipment is available in three standard sizes that can then be customised for each client. Of course, the client can adjust the speed of the screw and the temperature of the water on the factory floor, but major adjustments have to be done by the manufacturers. So far customers have been mainly in Europe, in the UK, Denmark, Spain, Germany, France and of course Iceland, as well as Canada. A network of dealers in Europe and Canada is responsible for sales and service of the machinery.

The frozen block in the first minutes
The block starts to break up.
Fully thawed mackerel after one hour in the thawing process.