What should the spool gap be?
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Today, I was repairing the oil filter on the compressor oil station and found an issue with the directional spool valve. The two filter elements are switched by this spool valve; when I opened it to clean it, oil still leaked out from the housing. Normally, when one of these components isn’t working, there shouldn’t be any oil leakage. After taking the directional spool valve apart for inspection, I found that it was a conical valve, but its axis wasn’t properly aligned! No wonder there’s a leak. What I would like to ask is, what should be the axial clearance for this conical spool valve? Let’s analyze it: if it’s too large, there will be internal leakage; if it’s too small, the slide valve becomes too tight when it’s time to replace the filter element, preventing the plate from moving. Those of you who have encountered this problem, please help!
Precise measurements will be taken tomorrow. I plan to fabricate a brass retaining ring that will serve as a sliding bearing; I’ll leave a gap of 0.05 MM. I wonder if this will allow for both sealing and easy rotation. Last edited by lovestory on 2009-3-19 22:12.]
Isn’t there anything like a seal ring at the position of the slide valve?
There’s no slide valve! The spool gland has an O-ring to prevent oil leakage
Where is the oil leaking from?
Since there was a high pressure difference alarm for one set of oil filters, it was necessary to disassemble them and clean them. Therefore, another set was switched to use; for the set whose filter was clogged, the cover was removed and the filter was taken out, but oil kept leaking out – this should not happen under normal conditions. It was suspected that there was a problem with the switching spool, and upon inspection, it was indeed the case: the spool was not properly aligned axially, which caused both filters to operate at the same time
Since there was a high pressure difference reported for one set of oil filters, it was necessary to disassemble them and clean them. Therefore, another set was used; for the set whose filter was clogged, the cover was removed and the filter was taken out, but oil continued to leak out – this should not happen under normal conditions. It was suspected that there was a problem with the switching spool. Upon inspection, it was confirmed that the spool was not properly aligned axially, which caused both filters to operate at the same time. Even after removing that set of filters from the system, the excessive axial clearance in the conical spool meant that its outer conical surface could not provide a proper seal, resulting in internal leakage. In other words, even without opening the filter covers, oil flowed through both filters, and it was impossible to remove either one from the system no matter what. Last edited by lovestory on 2009-3-19 23:19]