Can a reciprocating compressor crosshead thread be damaged and still be used?
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:The crosshead of a reciprocating compressor is connected to the piston rod via a threaded hydraulic connection. During maintenance, 4 threads on the crosshead were damaged; there are a total of 22 threads. Can it still be used?
It can be used; it’s fine for emergencies. However, if spare parts are available, it’s better to replace it with a new one.
There is no problem using it; it doesn’t affect the ability to secure the crosshead firmly. You can also consult the manufacturer to see if it’s permissible to use it.
If possible, can the pressure body be used to apply pressure at the original pressure level? I’m worried that with the usual pressure, the threads will deform and make it difficult to remove
Our compressor is having this problem: the pressure chamber seal is leaking oil, so it can’t build up pressure and won’t move. Is there any good solution? Please share your ideas!
The threads in this area are intended for locking purposes; they secure the lock after the piston rod is hydraulically stretched, thereby ensuring that the piston rod remains in its extended state. However, having fewer threads certainly means less security compared to when the threads are intact.
It is possible to artificially stretch the piston rod by placing a steel plate between the piston body and the cylinder, with a thickness slightly greater than the clearance in the cylinder; by then forcing the cylinder to rotate backward, the piston rod is stretched and the lock is released. When using this method, be sure not to rush and avoid applying too much force.
We considered this method, but were concerned that it might damage the cross-head pin and the large end cap, so we didn’t dare to use it. Additionally, fixing the piston with super nuts also doesn’t provide an appropriate point of application for force! If nothing else works, we’re ready to cut through the lock nut!
There’s no nut at the back of the piston! By adding steel plates, I mean adding them between the piston and the rear cylinder steel plate; the force exerted when turning the crank is quite large, so it’s easy for those connections to loosen.
Is the iron plate inserted from the valve flow channel?
Yes, remove one intake valve and turn the piston forward, thereby creating a gap at the rear end. Insert the steel plate through the intake valve, then turn the piston backward. It’s important to ensure that the steel plate is slightly larger than the clearance in the cylinder, so as to prevent the piston rod from being unable to move when turned. Additionally, the extension amount of the piston rod is not very large; it loosens with just a slight force applied. If there is a clearance of 5 mm, then it’s best to use a 6 mm thick steel plate for testing first. If that doesn’t work, the thickness can be increased slightly. The rotation of the shaft should be done slowly, and care should be taken when working; it’s also possible to use a timer to keep track of time. Check whether the piston rod has extended.