A study of sample withdrawal for lubricated systems. Part 2: Practical sample withdrawal and selection of proper sampling methods

摘要

Aims to use some of the sampling techniques and sampling routines, mentioned in Part 1 of the article, to perform practical tests to determine their differences in withdrawing samples. Uses two different types of systems, a hydraulic system and a gear system, together with some of the investigated sampling techniques. In order to find out the optimum sampling method for each of the two systems, uses a specification of requirements and a systematic approach, together with practical sample withdrawal from the two systems. For the hydraulic system, uses an on-line particle counter and bottle samples from valves, and for the gear system, applies drain-plug and vacuum pump sampling. It was found that for hydraulic systems on-line sampling is the most appropriate, if information on the elements is not required. If information on the elements is required, bottle sampling from a valve together with flushing of the valve should be performed. For the gear system no difference was seen between the samples taken with a vacuum pump and those taken from the drain-plug, and therefore an alternative method is suggested to improve the reliability of the sampling.