Experience sharing on on-site instrument failures
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I have been working on design in the office, and at most I go to the site to observe the construction; I lack experience with on-site instrumentation. That’s why I started this thread; I hope everyone can share some information about instrument failures they’ve encountered, and photos would be even better. Let me start: The Solvay hydrogen peroxide project, in non-explosion-proof environments, using plastic pipes, with hydrogen peroxide as the medium. The instrument enclosures were not grounded, and several instruments (temperature and pressure transmitters) were damaged during testing. It was only later that it became clear that plastic pipes tend to accumulate static electricity; even in non-explosion-proof environments, the instrument enclosures must be grounded. After being grounded, the instrument has never broken again.
The control valve, once installed, also needs to be degreased of oil. . . .
A few years ago, I worked as an engineer at a leading dye chemical factory in Shangyu, where I was involved in the fully automated setup of the feed and washing processes for filter presses. In complex environments (vibration and corrosion), pneumatic valves are the most prone to failure. Due to the vibrations caused by the frequent opening and closing of the pneumatic valve, the air pipe connections become loose, resulting in a pressure of less than 0.5 MPa in the instrument air, and the pneumatic valve is unable to open or close. The circuit connections become loose due to vibration and corrosion, resulting in different signals from the pneumatic valve, which prevents the valve from operating. What is most difficult to detect is that during the cold weather in winter, the condensate water from the instrument storage tanks is not properly drained, which causes water to enter the instrument air supply and freeze, blocking the instrument pipelines and preventing the pneumatic valves from functioning.
Shin-Nakano? It’s still Longsheng, haha
Try the hose with a stainless steel connector.
Gauges used air tubes and metal connectors; that was a long time ago. First is the safety inspection, which relates to potential hazards. Secondly, the joint part of the trachea leaks more when it is vibrating.
We have replaced all our plastic hoses with stainless steel ones