This paper analyses the principle of seal, the fault of leakage and the cause of fault to the sealing arrangement for upper bearing unit in SJ 2000 oil purifier, and gives the means of improvement.是什么意思_This paper analyses the principle of seal, the fault of leakage and the cause of fault to the sealing arrangement for upper bearing unit in SJ 2000 oil purifier, and gives the means of improvement.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句