During the disassembly and inspection of the piston in the first-stage compression cylinder of the reciprocating compressor, it was found that the wear in the outer support ring groove had increased by 10 mm; there were... in the piston ring grooves.
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During the disassembly and inspection of the piston in the first-stage compression cylinder of a reciprocating compressor, it was found that the support ring grooves and piston ring grooves were damaged to varying degrees; the outer support ring groove had expanded by 10 mm. Can this piston still be used?
One more question: what is the basis for designing the clearance between the support ring and the piston?
It’s rare for wear to reach this extent. . . What material is this piston body made of? And what material are the support rings and piston rings made of? How long has it been in use? This one can probably no longer be used; let’s use another one. However, it’s best to find out the cause of the wear before making the replacement.
This gap is too large; if it is to be used, piston rings and support rings must be custom-made, and the piston also needs to be modified
1. The main problem with piston groove wear is that the dimensions of the piston rings or support rings are not appropriate; in other words, the lateral clearance is too large. During operation, under the influence of air currents, the piston moves back and forth while doing work. Another possibility is that the medium contains ultra-fine solid particles. 2. I don’t know what material your piston is made of, nor whether it matches the piston rings and support rings, especially in terms of the hardness difference between them. 3. The clearance of the piston rings is determined during compressor design, based on the temperature of the medium and the thermal expansion coefficient of the piston ring material. Each operating condition and choice of material affect the required clearance, and there is no standard fixed for this. 4. If the wear amount is 10MM, it means the side clearance is at least 10MM larger, and the component cannot be used. It needs to be repaired or replaced. A larger side clearance increases the vibration of the compressor, as well as its noise level. This could lead to cylinder scoring. The side clearance of a normal PEEK piston ring is around 1 MM; in some cases, it’s only a few dozen microns.
Large press pistons are often made of aluminum alloy, and wear is normal. It is possible to machine the piston slightly and then have it fitted with a custom sleeve; we do this frequently.
The clearance of piston rings is primarily determined by thermal expansion and contraction, as well as the expansion coefficients of the intake and exhaust gases and the materials used. . .
It depends on what the diameter of your cylinder is
The clearance between the piston rings and support rings is primarily intended to prevent the piston rings and support rings from becoming stuck inside the cylinder due to thermal expansion during operation, which could lead to cylinder scoring. During design, it is based on the temperature of the operating environment and the expansion coefficient of the surrounding materials; as for everything else, I’m not sure, as I’m not a professional designer.
In the past, the aluminum pistons of our gasoline hydrogen compression machines wore out; later on, custom-made piston rings and support rings were used