Screw refrigeration compressor

　　Screw refrigeration compressors are all lubricated by oil injection. According to the different ways of connecting the compressor and the motor, they are divided into three types: open type, semi-closed type and fully closed type.

　　Open type unit: The compressor is connected to the motor through a coupling. It is required to install a reliable shaft seal on the compressor extension shaft to prevent the leakage of refrigerant and lubricating oil.

　　Semi-closed type unit: The motor and compressor are integrated and connected by a flange in the middle, which can effectively prevent the leakage of refrigerant and lubricating oil. The motor is cooled by refrigerant, eliminating the noise of the motor cooling fan in the open type unit.

　　Fully closed type unit: The motor and compressor are enclosed in a container, which completely eliminates the leakage of refrigerant and lubricating oil and minimizes the noise. The refrigeration capacity range of this refrigeration compressor under standard working conditions (evaporation temperature: -15℃, condensation temperature: 30℃) has exceeded 3500KW.

　　Open type

　　Advantages:

　　(1) The compressor and the motor are relatively separated, and there are no special requirements for the motor, so the compressor has a wide range of applications.

　　(2) The same compressor can adapt to different refrigerants. In addition to using halogenated hydrocarbon refrigerants, ammonia can also be used as a refrigerant by changing the material of some parts.

　　(3) Different capacities of motors can be used according to different refrigerants and operating conditions.

　　(4) The cooling capacity of a single head unit can reach more than 2 million kcal.

　　(5) Low cost and low price.

　　Semi-closed type

　　Advantages:

　　(1) Due to the semi-closed method, the motor and compressor are integrated into one design, so the noise and vibration are low. There is no leakage of Freon and lubricating oil in the open type unit, which reduces the user’s maintenance and management costs and will not affect the user’s normal use due to leakage.

　　(2) Due to the semi-closed method, the motor and compressor are integrated into one, and the built-in oil separation silencer greatly reduces the operating noise. The noise difference between the open type and the semi-closed type with the same cooling capacity is about 15dB(A).

　　(3) Since the built-in oil separator adopts the internal pressure difference oil supply method, there is no need to equip an external motor to drive the oil pump, which improves the energy efficiency ratio of operation. The energy efficiency ratio under the nominal working condition of the air conditioner is generally greater than 4.5.

　　(4) For occasions with higher requirements, double or three heads can be used. Each refrigeration system is relatively independent. Once a system fails, other systems can work normally, which will not cause much impact on production and the environment.