Please discuss the reasons for severe wear of the piston ring support rings in reciprocating compressors, as well as cylinder scuffing
Thread Content
This compressor is new; it has been in use for 6 years. For various reasons, after only 7,600 hours of operation, the piston rings and support rings in four out of the six cylinders became severely worn, the piston rings broke, the support rings fractured, and the cylinders were badly damaged. Please help analyze the reasons!
It’s possible that after prolonged operation, issues with the foundation or the machine itself cause the foundation to sink, which in turn leads to poor alignment. This results in too small a gap between the piston rings and the cylinder walls, leading to wear on those walls. It’s also possible that the medium used is too dirty, with particulates ending up on the surface of the cylinder walls; over time, this causes wear on the piston rings.
Both piston rings and support rings are wear-prone components; it’s already quite good that the machine has run for over 7,000 hours. You should have checked the gap of the support rings in advance, as damage to these rings can easily lead to cylinder scoring
As a supplementary note, the gap between the upper and lower parts of the 1-crosshead has changed. 2 The medium is dirty. 3 The lubrication may not be sufficient, or the lubricating oil is not clean
Is it oil-lubricated? High temperatures can also easily make the support ring brittle, right?
After installation, is regular turning of the shaft carried out? Are piston rings oil-lubricated? 1. If the oil injection pump is not started by periodic cranking, poor lubrication of the compressor piston rings leads to dry friction upon restart. 2. What material are the piston rings made of? If they haven’t been replaced in 6 years, consider whether the material has aged normally. 3. If it has been shut down for too long, is the compressor piping system clean?
Let’s first answer a few questions from those above. 1. Is it oil-lubricated, as asked by the person on floor 5? ” This compressor is oil-free lubricated ； 2. Has regular turning of the shaft been carried out after installation on floors 2 and 6? Are piston rings oil-lubricated? ” Over the six years while it was out of service, the shaft was turned once a week, with no lubrication for the piston rings. Also, could a valve failure cause this situation? Could the rigid support be the cause of this fault? The four cylinders with severe wear exhibited the least vibration, while the two cylinders with almost no wear had vibration amplitudes 4 times higher than those of the other four cylinders!
Personal opinion for reference only: 1. Test the material of the piston rings and support rings to determine whether it is due to material issues (such as incorrect material or aging)； 2. Verify the inspection records; the temperature of the cooling water affects its service life (high temperatures certainly have an impact, and it’s also necessary to check whether there were any interruptions in the water supply) ； 3. Alignment issue: Please carefully verify the alignment of the cylinder; this is the most likely cause. In particular, check the wear on the piston and the cylinder liner – be sure to observe the wear marks closely. Thank you! ! Hehe
This compressor does not have cylinder cooling water, so there is no need to consider this possibility! But material aging, the intrusion of impurities, foundation settlement, and poor alignment are the reasons I believe are more likely, as it has been six years since installation; the inlet filter is severely damaged, and the main unit and cylinders are on different reinforced concrete foundations!
Maintenance should be strengthened; it’s been 7,600 hours, almost a year already! The service life of oil-free compressor support rings cannot be that long, unless it is a very small compressor. It took us several modifications to achieve over 1 month (100 tons). Regularly checking the downward movement of the piston rod and keeping records can help avoid this issue. The possibility of redoing the foundation is likely very low; strengthening monitoring and conducting preventive maintenance are the best approaches. Inadequate maintenance.
Thank you all for your replies! The service life of the accessories provided by the compressor manufacturers is as follows: the support rings and piston rings have a lifespan of over 8,000 hours; moreover, the piston rings and support rings of our factory’s two other compressors with similar capabilities can operate for 15,000 hours without any problems! I wonder how much the compressor’s speed affects its service life, and whether there is a quantitative relationship