Almost free from the pressure of the gas transmission capacity. , Can still maintain high efficiency within a wide operating range. The screw compressor, while having the advantages of a single-stage pressure ratio is high, but as the pressure ratio increases, the leakage loss is also increased rapidly, so Cryogenic operation efficiency is remarkably lowered.
2 balance, vibration
Screw compressor reciprocating mass inertial force, the dynamic balance performance. The screw compressor is a rotary type compressor, it has no centrifugal or compression movement. Its compression pressure of the exhaust gas vibration is very low, because the screw rotates, the recovery compression occurs six times a week, such as compression placed during operation of a coin does not fall due to vibration.
The piston compressor runtime vibrations.
The scroll-type compressor due to the suction, compression and exhaust process is also carried out continuously, and the pressure increased slowly, so the magnitude of the torque variation is small, small vibration. At any frequency, the vibration and noise of the scroll-type compressor, than the piston compressor and the low rolling rotor compressor, this is because the scroll-type compressor of the compression process, the torque change is very gentle, and by secondary inertial force balance its good dynamic balance, low vibration and noise level.
3 gas transmission coefficient
Scroll compressor suction, compression and exhaust continuously unidirectionally, directly inhale harmful overheating of the suction gas is small, and no clearance volume expansion of the gas in the process, and thus the high gas transmission coefficient.
Rolling piston compressor suction valve piece, small clearance volume, high gas transmission coefficient, and the process of breathing resistance is very small (small suction speed nor suction valve), and thus the gas transmission coefficient than the same capacity The piston compressor is about 20% higher.
The piston type compressor due to the clearance volume, the pressure loss of the intake and exhaust gas with the cylinder wall between the heat exchange as well as leaks, etc. factors. The actual gas transmission capacity of the compressor is always less than its theoretical gas transmission capacity.
Screw refrigerant compressors, the working conditions are not at the same time, the gas transmission coefficient roughly 0.7 to 0.92, small gas transmission capacity of high pressure ratio to take lower limit, take the upper limit of the large gas transmission volume and low pressure ratio. As the screw compressor with no carry, the exhaust valve and the clearance volume, the new toothed applications and injector so that the sealing and cooling effect greatly improved, so the gas transmission coefficient than the piston, and other types of rotary compressors are high and change a flat.
4 gas transmission capacity adjustment
Gas transmission capacity control slide valve is used to adjust the gas transmission capacity of a structural , screw refrigeration compressor screw refrigeration compressor gas transmission capacity adjustment in a variety of ways, but the slide valve adjustment method to obtain the universal application. Used in the volume of the primitive part of the working fluid flow back to the suction chamber, to reduce the volume of the primitive values ??(to postpone the starting position of the compression process), in order to achieve the stepless adjustment of the gas transmission capacity.
The scroll-type compressor and the scroll compressor rotor can be used to variable rotational speed adjustment method to change its transmission volume, and the two compressors are applicable to the change of speed in a wide range of occasions.
The piston compressor is the most simple method of delivery of a gas quantity adjusting compressor runs intermittently, when the system reaches a set minimum temperature, the compressor stop: when the system temperature is higher than the set maximum temperature, the compressor starts. Energy regulation only applies to power about 10KW small refrigerator, open to stop frequently for the larger capacity of the compressor, the machine is not only energy loss, but also affect the life of the machine and the power supply circuit voltage stability, affecting Other devices work properly.