The performances of ultra low temperature recirculating chillers are different because of their different compressors. Compared with piston compressor, the structure of screw-type compressor tends to be more precise, so when users need to select ultra low temperature recirculating chillers, they should understand the cooling operation.

When working, the ultra low temperature recirculating chillers’ screw-type compressor will spray lubricant into the working chamber, functioning as lubrication, cooling, sealing, soundproofing, lubricating for main bearing , thrust bearing and shaft seal, a push for pressure oil of oil piston and balance piston. These oils will mix with high pressure gas to be expelled from compressor.

Suction strainer: the ultra low temperature recirculating chillers’ suction strainer is comprised of shell and metal filter mesh. The shell is installed with suction thermometer, pressure gauge and priming valve, among which priming valve is the oil position for unit operation that needs paying attention to.

Oil cooler: the lubricating oil isolated from the engine oil of ultra low temperature recirculating chiller leads to the temperature rising ( close to exhaust heat temperature) for it absorbs friction heat and the heat of air. The oil temperature is so high that viscosity decreases, weakening the sealing function, increasing internal leakage and lowering the efficiency of compressor. Thus, it is necessary for lubricant to go through cooling for purpose of reuse. The oil cooler of ultra low temperature recirculating chiller is definitely for cooing the oil.

Coarse oil filter: in order to ensure the working of oil pump of ultra low temperature recirculating chillers, the lubricating oil should be purified through coarse oil filter before entering the oil pump.The later cleanliness of coarse oil filter should be checked for the first operation of the machines. And overhauling the filter mesh regularly should be on the basis of the system cleanliness. Gas or kerosene can be applied to clean the filter mesh, and get them clean with dry air for continuous use.

Oil- pressure adjusting valve: the ultra low temperature recirculating chillers’ oil-pressure adjusting valve is to regulate the injection pressure of compressor. If the ingoing oil pressure of compressor is excessive, the fuel-injection quantity will be overmuch, not only influencing the air removal of compressor but wasting work of it as well as increasing the possibility of shaft tunnel oil leakage of ultra low temperature recirculating chillers. Otherwise, the fuel-injection quantity will be too small, degrading the function of lubricant.

Oil separator: the oil separator of ultra low temperature recirculating chillers’ compressor unit is divided into vertical type and horizontal type. The interior of oil contains three chambers. The one next to the staving of compressor is for keeping the oil level, whose external shell is placed two sight glasses at top and bottom to observe the height of oil (automatic unit has oil level controller). That near the staving of electrical machinery is for installing the highly efficient filter element to separate the quadric oil, whose outboard also has a sight glass so as to decide whether to return oil or not based on the oil level.

The ultra low temperature recirculating chillers’screw-type compressor is quite complicated, thus it is good to have some relevant knowledge of its cooling and accessories when buying.