Forum: Reliability & Maintainability Questions and Answers
Topic: Reliability & Maintainability Questions and AnswersTopic Posted by: Reliability & Maintainability Forum (firstname.lastname@example.org )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998
Original Message:Posted by: raja rizwan imtiaz (email@example.com )
Date posted: Sun Feb 16 0:57:10 US/Eastern 2003
Subject: functinal failure of safety valves
Recently, we have faced recurring pressure safety valve popping problem in few of the safety valves installed in high pressure steam service. While conducting safety valve failure investigation, it was observed that the problematic psv's spring has reduced in height about 7.0mm compared to the original (new) spring. original spring height = 207 mm and the used (old) measured spring height = 200mm Currently, we are using only visual inspection criteria for the replacement of safety valve critical parts i.e. spring, spindle etc. However, we are looking for introducing the dimensional criteria as well to avoid such failures. If someone help answer following · Are you applying dimensional measurement criteria for the psv's critical parts or only visual inspections are done to adjudge the parts fitness. · What is the dimensional measurement criteria for spring replacement. Example could be for any service.