Ammonia Blast Freezer Evaporator

Ammonia Blast Freezer Evaporator

An ammonia blast freezer evaporator is a key component in an ammonia refrigeration system, mainly used for rapid freezing in industrial and commercial fields.

Working Principle

The ammonia liquid in the evaporator absorbs the heat of the object to be frozen, vaporizes and becomes ammonia vapor. The specific process is as follows: The high - pressure and high - temperature ammonia liquid first passes through the throttle valve and is throttled and depressurized to enter the evaporator. In the evaporator, the ammonia liquid absorbs the heat of the surrounding objects or the medium to be cooled, changes from a liquid state to a gaseous state, and the generated ammonia vapor is sucked away by the compressor, thus continuously realizing the freezing and cooling effect.

Structural Features

Coil Tube: Usually made of steel or stainless - steel tubes. For example, some ammonia blast freezer evaporators use 20 - diameter steel or stainless - steel tubes. The tube arrangement may be in the form of vertical tubes or finned tubes. In the vertical tube evaporator, the ammonia liquid is distributed in the vertical tubes, and the evaporation heat transfer is carried out on the tube wall. The finned tube evaporator increases the heat transfer area through fins, improving the heat transfer efficiency.

Shell: Commonly made of galvanized steel plates, stainless - steel plates, etc. It has the functions of protecting the internal components and guiding the air flow.

Gas - liquid Separator: Installed at the outlet of the evaporator or on the upper header of the vertical tube evaporator. Its function is to separate the ammonia liquid carried in the ammonia vapor to prevent the liquid from entering the compressor and causing liquid hammer damage.

Fan: In the air - cooled ammonia blast freezer evaporator, a fan is equipped to force the air to flow, so as to enhance the heat exchange between the air and the evaporator coil and improve the heat transfer efficiency.

Defrosting Method

The ammonia blast freezer evaporator often uses hot ammonia defrosting. The high - temperature refrigerant gas discharged from the compressor is introduced into the evaporator, and the heat released by the condensation of the superheated steam is used to melt the frost layer on the outer surface of the evaporator. At the same time, the original accumulated oil in the evaporator is discharged under the action of pressure difference. This method has the advantages of short defrosting time, low labor intensity and good defrosting effect, but it has complex operation and large energy loss.

Application Fields

Widely used in food processing, cold storage and other industries. In the food processing industry, it is used for the rapid freezing of meat, seafood, fruits and vegetables, etc., which can quickly reduce the temperature of food to below the freezing point, inhibit the growth of microorganisms and the activity of enzymes, and maintain the quality and freshness of food. In cold storage, it is used to maintain the low - temperature environment of the storage, ensuring the safe storage of various goods.