HITACHI SCREW COMPRESSOR

The Best Compressor for Energy Efficiency & Environmental Sustainability

Operating Principle of The Screw Compressor
The refrigerant gas and oil flow into the oil separator together. The cyclone system begins to separate the refrigerant gas and oil by centrifugal force. Refrigerant gas is ejected from the discharge port, and oil drops down to the bottom tank.
Lubrication oil is required for sealing the area between the two screw rotors as well as for the lubrication of the bearings, but it decrease the efficiency of air-conditioning units at heat exchangers. The oil and refrigerant are separated by centrifugal force in the cyclone oil separator. After it is compressed by the screw rotors, refrigerant gas enters the upper side of the separator.
Refrigerant gas then enters through the lower side of the separator, and the oil is separated by centrifugal forces to the wall of the separator. Oil then goes down to the oil tank along the wall. The oil is accumulated in the oil tank, which is located on the bottom of the separator, and only refrigerant gas is discharged from the discharge port, which is located on the upper side of the separator. The oil that is accumulated in the tank is then supplied to the screw rotors by pressure difference. Unlike other compressor structures, this structure doesn't require mechanical parts such as an oil pump for its oil supply, which leads to higher reliability for the compressor.