3941 -- Predicting Lubricant Performance in Refrigerant Compressors: A Comparison Between Component Testing and Benchtesters PDF

To identify the relative effectiveness of various benchtesters for screening lubricants for refrigerant compressors, a comparison is made between the wear data obtained from the high-pressure tribometer (HPT), four-ball and pin/block testers, and those obtained from accelerated component (compressor) tests. Based on these data, the rankings of the lubricants obtained from the various testers are compared to the rankings of the same lubricants obtained from the component tests. The accelerated component tests were conducted by four companies. These companies provided wear data for wrist pin/bearing and piston ring/cylinder contacts in reciprocating compressors, and a vane/piston contact in a rotary compressor. Each compressor was tested with three different lubricants. For the reciprocating compressor, all lubricants were esters and the refrigerant was R134a. For the rotary compressor, two alkylbenzene lubricants and a mineral oil were tested with R22. Agreement between the data obtained from each of the specimen testers and the component data is approximately 65%. The HPT data obtained also suggest that oil ranking is affected by environmental conditions.

KEYWORDS: year 1996, calculating, lubricants, performance, refrigerants, compressors, comparing, components, testing, reciprocating compressors, R134a, R22, viscosity, friction, temperature, pressure