用扫描电子显微镜分析液压系统堵塞的原因

Cause Analysis of Hydraulic System Blockage by SEM

某液压系统配有10μm和3μm两级过滤器,液压介质是合成无灰抗磨液压油。在使用过程中,出现了10μm过滤器堵塞而3μm过滤器没有被堵塞的现象。借助于扫描电子显微镜,对液压油和过滤器进行了分析,找到了10μm过滤器堵塞而3μm过滤器没有被堵塞的原因。堵塞微粒来源于液压系统中气泡爆裂产生的瞬间局部高温导致的液压油热裂解,这些热裂解微粒(<1μm)悬浮于液压油中,但对液压油的影响甚微。过滤时,液压油与10μm过滤器中的玻璃纤维发生摩擦产生静电,由于液压油与玻璃纤维的导电性均较差,使静电积累。在静电的作用下,热裂解微粒被牢牢地吸附在玻璃纤维上造成10μm过滤器堵塞。而3μm过滤器为金属材质,导电性好,不会产生静电,也就不会吸附热裂解微粒,从而不会发生堵塞。

A hydraulic system had 10 μm and 3μm two-stage filters.The hydraulic medium was synthetic ashless antiwear hydraulic oil.During use ,there was a phenomenon that the 10μm filter was clogged and the 3 μm filter was not blocked.It was analyzed that the hydraulic oil and filters by means of scanning electron microscope. The reason that the 10 μm filter was clogged and the 3 μm filter was not blocked was found.Blocking particles were derived from thermal cracking of hydraulic oil caused by transient local high temperature caused by bubble burst in hydraulic system.These pyrolysis particles (<1 μm) were suspended in hydraulic oil and had little effect on the hydraulic oil.When filtering,the hydraulic oil rubbed against the glass fiber in the 10 μm filter to generate static electricity.Due to the poor conductivity of hydraulic oil and glass fiber, static electricity accumulated.Under the action of static electricity,the pyrolysis particles were firmly adsorbed on the glass fibers,and caused the blockage of 10 μm filter.The 3 μm filter was made of metal,which had good electrical conductivity.It did not generate static electricity,and did not adsorb thermal cracking particles,so that it would not clog.