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A common request is to provide the customer with a cause of failure for a specific device. This typically includes photographing any out of the ordinary conditions or foreign material, pre-testing the device, conducting a disassembly inspection, reviewing the condition of internal components for indicators such as galling, seat/bearing point distortion, signs of material failure or fatigue, and reviewing process conditions provided by the customer. This information is reviewed, and the customer is provided with a report outlining the cause(s) of the failure.

Pilot-Operated Safety Relief Valves (POSRV) are a great solution for many industrial applications. However, it is not uncommon to get a call from the customer stating that a POSRV is lifting during start-up. In order for the POSRV’s main piston or disc to remain in the closed position, there has to be sufficient pressure in the main valve’s dome. The dome is loaded with pressure that passes through small passages in the pilot. If the POSRV is lined up too quickly, this does not allow enough time for the pressure to pass through the pilot and load the dome. This will result in the main valve lifting because the force applied by the dome pressure isn’t enough to keep the main piston or disc closed.

Remote sensing is another common source of discussion. Typically, remote sensing is used when a POSRV is installed where the nonrecoverable inlet loss is greater than 3% of the set pressure. The purpose of remote sensing is to tie in close to the protected equipment and supply the pilot with pressure in which the nonrecoverable line loss is equal to or less than 3% of set pressure. There tends to be a lot of questions regarding this application.