Discussion on oil leakage from the compressor wiper ring
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This post was last edited by hu676 on 2017-3-19 at 17:36. 1. The oil scrapers of the two cylinders have the same structure; their piston rods are new, and there are no defects in the friction surfaces. 2. The axial clearance of the oil scrapper rings is the same, and the oil return channels are unobstructed. Question: One cylinder performs well, while the oil wiper ring in the other cylinder causes significant oil leakage. Measure 1: Adjust the radial clearance of the crosshead to ensure that the piston rod movements on both sides are equal, but this did not improve the situation. Measure 2: Remove the skeleton oil seal with serial number 9 ； At the same time, chamfer the bottom of the oil seal box (see the dashed line and text description in the upper right) ； Finally, adjust the perpendicularity between the oil-scraping ring and the piston rod. After applying Measure 2, the side with severe oil leakage no longer showed any leakage at all, showing a better effect than the other side! Analysis of the cause: I believe the main reason is the lack of perpendicularity between the oil-scraping ring and the piston rod; it has little to do with the skeleton oil seal or the chamfering. But the experienced worker believes that the main reason is that the oil seal on the frame contains oil, and after chamfering the vehicle, the oil can flow smoothly down along the chamfer. But I just don’t understand: if the oil-scraping ring is leaking oil, then there will be oil on the piston rod. So shouldn’t the presence or absence of an oil seal or chamfers have no impact on oil scraping? ? ? I would like to ask everyone: do oil seals and chamfers serve any purpose in the structure shown in the diagram? To verify the effectiveness of the oil seal, it was put back in place, and the machine was tested for half an hour with no oil leakage observed. But since the oil seal used is damaged, it’s not possible to find one of the same size for now. So an oil seal with an increased outer diameter and greater thickness was used! I wonder if it has an impact on the structure?
When the oil-scraping ring rubs against the piston rod below, there must be no axial passages, as that would cause oil leakage.
I spent half a day studying the drawings you sent; something seemed off about them. I wasn’t even sure about the direction from which the oil comes. If the oil comes from the left, then the skeleton seal on the right serves no purpose other than storing oil. If the oil comes from the right, then the direction of the cutting edge of the oil-scraping ring is incorrect – it’s facing away from the direction of the oil flow. I think there are serious problems with the design of this oil scraper component.
It is likely that there is a poor connection between the oil-scraping ring and the piston rod. Check whether the oil-scraping ring has burrs, whether it makes good contact with the piston rod, and whether the axial clearance is too large; also measure the coaxiality
How to adjust the perpendicularity of the oil scrapper ring and the piston rod?
What is the purpose of the oil-blocking ring in front of the oil-scraping ring? Is it open?
To prevent oil from flowing in, a large amount of oil is discharged by the crosshead; relying solely on the oil-scraping ring is not effective, so an oil-blocking plate and an oil-resistant ring are needed to work together with the oil-scraping ring. The oil-resistant ring has the same structure as the tangential ring
Are there any requirements for the gap in this oil scraping groove? Several attempts at oil scraping didn’t yield good results; I’m considering reducing the gap to see if that helps
Generally, 5 to 10 gaps are required. The axial gap should not be too small; if it is, the expansion of the ring will fill that gap. Moreover, the oil-scraping effect has little to do with the axial gap, unless the axial gap is extremely large or extremely small