Breakage of the cylinder head bolts in a reciprocating compressor
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Some time ago, we replaced the cylinder liners in our CNG reciprocating compressor; more than 20 days after it was reinstalled and put into use, it developed a fault. After detecting abnormal noises from the primary intake valve, when attempting to open it for inspection, the bolts securing the cylinder head could not be removed (I was not there at that time). As a result, two of the bolts broke, with the parts that were embedded in the cylinder also breaking; it took a lot of effort to get those bolts out. The valve stem of the gas valve has come loose, and there is no fault with the spring element of the valve disc (we are using the new type of valve disc). The ring gasket that the valve is pressed against has a cut, and the nut is damaged. Our intake pressure is 3.5 MP; it broke down after just over 20 days of normal use. The compressor has been in operation for less than 3 years. Is this situation caused by the threads being misaligned when tightening the upper valve cover bolts? Since I have been here many times, this is the first time I’ve encountered such a situation. I asked the senior employees, and they said they haven’t had this kind of problem in years. Can someone give an answer? Analysis of various reasons.
The filaments are unevenly stressed. It could also be a material issue
The veteran employee said it was a problem with the filaments. But I tightened it absolutely, and I tightened it further using that tensioning rod with a limited force. Moreover, some problems only appeared after more than twenty days; during that time the machine was used frequently, the temperature remained normal, and there were no significant issues with the noise.
1. The gasket is not positioned correctly; the intake valve must be able to rotate freely on its seat in order to be installed properly. The area where the gasket sits must be cleaned thoroughly before installation. 2. The gland screw of the valve cylinder is not tightened properly or is misaligned; it must be tightened after the valve cover bolts have been tightened first. Has the push rod of the unloader not been bent or damaged? Is there an arc-shaped groove drawn on the top of the valve cylinder? It would be best to have photos from the site; it is recommended to replace all valve cover bolts.