Regarding online calibration of safety valves

There are many restrictions associated with online verification, and it is necessary to modify the pipelines before and after the safety valve

Generally, for safety valves that require online verification, a stop valve should be installed at the inlet; the diameter of this stop valve merely needs to meet the requirements for safe venting. For applications where leakage requirements are not high, installing a ball valve is also an option. For applications with high sealing requirements, a rupture disc can also be considered to be installed in front of the globe valve. This allows for the online verification of safety valves. Generally, those that require online verification are designed with a margin of safety (for example, one in use and one as a backup, with the two safety valves having different set pressures, etc.). Not all safety valves will go offline at the same time, as that would pose a safety risk.

It is still advisable to perform regular offline calibration on important safety valves. For less critical valves that are not subject to mandatory inspection, online calibration can be used; however, it should be noted that online calibration cannot determine the sealing performance of safety valves.

At present, some safety valves cannot be calibrated offline for various reasons, and the equipment cannot be stopped either; therefore, online calibration is planned

Detachable safety valves should all undergo offline calibration. Those that cannot be disassembled are subjected to on-line verification, such as welded safety valves in boilers. After all, online verification poses certain security risks, and the performance testing of safety valves is not as thorough as that done offline.

Relevant qualified manufacturers have already visited the site, and it is still possible to meet the online requirements; no changes to the pipelines are necessary

Internal leakage may occur after the safety valve activates, which is also one of the risks

It’s best to make the safety valve offline! The verification values are quite accurate! When working online, the safety valve cannot be removed, or there is a pre-installed safety valve; in such cases, it’s not possible to measure the sealing performance! They are usually sent to the special inspection agency or the boiler inspection agency! But the process of sending it to a special inspection agency usually takes a long time! A batch of safety valves needs to be sent 2 to 3 times. On the 1st attempt, after 3 days, it was said that there were 2 items that needed repair! More money is needed! It was only later that I found out it was a bribe. Lever-type safety valves and gravity-type safety valves can be calibrated online! Generally, this does not apply to those used in domestic steam boilers! No spare safety valve needed! Steam engine! Boiler! All of them need backup safety valves! A batch sent for inspection! Replacing it with a spare safety valve will not delay production! We all have third parties conduct verification! Home service! Free repair! On-site verification! It saves time and effort! An inspection conducted by a third-party testing agency, which operates between the two parties involved, can be considered an impartial inspection. Generally, third-party testing agencies are qualified, have technical support, and are equipped with advanced instruments; the test reports they issue are authoritative. It complies with national standards and corporate standards. Their qualification code is CMA. CMA: A product quality inspection agency that has obtained a certification for metrological compliance. Offline testing: Offline testing involves installing the safety valve on a testing bench, then using a testing medium to activate the valve, and confirming the opening pressure by observing the pressure gauge. This method cannot take into account the calibration of safety valves designed to handle back pressure, as well as those used with media at high or low temperatures. On-site calibration is also a form of offline calibration; it simply involves transporting the offline safety valve calibration bench to the location where the safety valve is installed, mounting the valve on the bench, and then using a calibration medium to activate the valve, with the opening pressure being determined by observing the pressure gauge. This method cannot take into account the calibration of backpressure safety valves, as well as those for media at high or low temperatures. Online calibration of safety valves is a more advanced method of calibration that is closer to the actual operating conditions. Online verification involves using external forces to measure the downward spring force acting on the safety valve, thereby determining its opening pressure. This method generally does not affect production and there is no need to change the system pressure; however, it cannot assess the sealing performance of the safety valve. Hope this can help you

If possible, conduct offline verification; there are many more requirements for online verification, and the associated risks are also higher.

Detailed! ! Be able to provide detailed proof that you truly have the capability! !