Reciprocating Compressors: Basics, Oil Selection and Refueling Tips

The reciprocating compressor is a classic positive displacement compressor, widely used in household refrigerators, refrigerated display cabinets and other equipment.

It has obvious advantages: simple structure and easy refrigerating capacity adjustment. However, it also has drawbacks, namely relatively low volumetric efficiency and energy efficiency.

When it comes to the refrigeration oils commonly used in reciprocating compressors, there are mainly two types: mineral oils and alkylbenzene oils, with the viscosity grade mostly choosing ISO VG 46.Mineral oils have the edge of low cost but are poor in oxidation resistance and anti-aging performance; alkylbenzene oils, though a bit more expensive, are far superior in overall performance.

Another point to note is that most reciprocating compressors adopt a fully sealed structure, making oil replacement rather inconvenient. Therefore, it is definitely a wise choice to prioritize alkylbenzene oils with a long service life when selecting lubricants.

There are also requirements for the refueling volume: generally, filling it up to 1/3 of the crankcase volume is sufficient. Overfilling will increase the oil viscosity and the energy consumption of the compressor during operation, which will do more harm than good.