Classification of screw chillers and what to pay attention to in operation

Some screw chillers need to be filled with refrigerant at the user’s site, and the filling amount of the refrigerant and the refrigerant grade must be in accordance with the regulations. Insufficient refrigerant charge. will result in insufficient cooling. Excessive refrigerant charge will not only increase costs, but may also have adverse effects on operating energy consumption.

Sufficient refrigerant should be prepared in advance before charging refrigerant. When filling, it can be filled directly from the special filling valve. Since the system is in a vacuum state, the pressure difference between the refrigerant in the cylinder and the system is large. When the valve is opened (the air in the connecting pipe should be blown out with the refrigerant first, so as to prevent the air from entering the unit and affecting the performance of the unit), the refrigerant is quickly released from the cylinder. After filling the system, the filling valve should be closed first, and then the connecting pipe should be removed.

When the heat dissipation of the condenser is poor, the compressor efficiency is low and the operating current increases. When the air-cooled high-pressure pressure rises to 24kg/cm2, and the water-cooled high-pressure pressure rises to 20kg/cm2, the compressor is tripped by the high-pressure switch protection, and the compressor stops Operation, poor heat dissipation, high pressure overload and a fault code or fault indication is displayed. At this time, please check whether the circulating water of the cooling tower is normal, whether the temperature of the cooling water is too high, whether the cooling tower fan pump is running, and whether the cooling water valve is fully opened (please check whether the cooling tower is fully open). Whether the radiator is dirty or blocked), press the reset button after the above is normal, or shut down and restart to operate normally. If high pressure overload occurs frequently, please arrange to clean the condenser as soon as possible.

The normal operation standard of screw chiller should meet the following points:
1. The oil temperature of the compressor is about 40-55 ℃;
2. The exhaust temperature of the compressor is 45-90 ℃, and the maximum temperature shall not exceed 1.05 ℃;
3. The exhaust pressure of the compressor is 1.8~1.47MPa (gauge pressure);
4. The oil pressure of the compressor is 0.2~0.3MPa (gauge pressure);
5. During the operation of the compressor, the sound should be uniform and stable, and there should be no abnormal sound;
6. The evaporation temperature of the unit should be 3-4 ℃ lower than the outlet temperature of the refrigerant water, and the outlet temperature of the refrigerant water is generally about 5-7 ℃;
7. The condensing temperature of the unit should be 3-5 ℃ higher than the cooling water temperature; the cold pole and temperature should generally be controlled at about 40 ℃, and the condenser inlet water temperature should be below 32 ℃.

External surface of combined cold storage:
Clean with mild detergent and warm water to maintain surface finish, do not use abrasive cleaners or abrasive pads for scrubbing.
The inner surface of the combined cold storage:
Use household cleaners, amino cleaners and detoxification solutions to clean the interior surface, which will not damage the surface , Do not splash water on electrical parts, do not use solvent, oil or acid cleaning agent.

Classification of screw chillers:
1. According to the air conditioning function, it is divided into single cooling type and heat pump type.
2. According to the different refrigerants used, it is divided into two types: R134a and R22.
3. According to its condensation method, it is divided into water-cooled screw chiller and air-cooled screw chiller!
4. According to the sealing structure of the compressor, it is divided into open type, semi-closed type and fully closed type.
5. According to the structure of the evaporator, it can be divided into ordinary type and flooded type.
6. According to the different screw refrigeration compressors used in the screw chiller, it is classified. Screw refrigeration compressors are divided into two types: twin-screw and single-screw. Twin-screw refrigeration compressors have a pair of rotors with helical teeth gnawing in opposite directions. The single-screw refrigeration compressor has a rotor screw with 6 helical grooves processed on the outer cylindrical surface. There are exactly the same planetary gears with 11 racks installed vertically on the left and right sides of the butterfly and rod! A detailed understanding of the classification of screw chillers is undoubtedly of great help to friends who need to purchase screw chillers!

Calculation method:
1: Volume (liters) × number of liters of temperature ÷ heating time (minutes) × 60 ÷ 0.86 (coefficient) = (W)
2: Volume (tons or cubic meters) × number of liters of temperature ÷ heating time (hours) ÷ 0.86 (coefficient) = (KW) if you bring in your data, you can get 4 hours 10000L×(15-7)÷4h÷0.86=23255W =23.255KW 5 hours 10 tons×(15-7)÷5h÷0.86=18.604KW

Post time: Feb-12-2022