Can a valve be installed upstream of the safety valve?

After overpressure occurs, the safety valve will trip again; installing other valves doesn’t help, doesn’t this undermine the function of the safety valve?

What if the safety valve needs to be inspected?

This post was last edited by Guangzhou Uprising on 10/19/2018 at 10:55; a detailed explanation can be found on page P26-B.9.4 of GB150.1

Here, not only must the manual valve be turned on, but the valve also needs to be fully open, with a seal put in place! Just turn it off during repairs! But it is indeed not allowed to install a manual valve on the boiler’s safety valve!

Devices that require regular testing should be equipped with valves to facilitate removal for inspection, but once installed, they need to be sealed with a seal.

The technical specifications are stated in a basically consistent manner, and strict requirements are applied where there are discrepancies. 1. By \"upstream,\" as mentioned by the owner, it refers to the area between the safety valve and the pressure vessel, and installation there is generally not allowed. 2. Those that need to be installed for the purpose of calibrating safety valves are generally also not allowed. But why are some allowed to be installed while others aren’t? Clause (4) of 9.1.3 in TSG21-2016 provides a loophole. “For pressure vessels that contain media with extremely high, high, or moderate toxicity, explosive media, corrosive or viscous media, or valuable media, in order to facilitate the cleaning and replacement of safety valves, a stop valve may be installed between the overpressure relief device and the pressure vessel, provided that this is approved by the person in charge of safety management at the using unit and that reliable preventive measures are put in place. During normal operation of the pressure vessel, the media valve must remain fully open (either sealed with lead or locked); the design and diameter of the stop valve must not interfere with the safe operation of the overpressure relief device. ” The requirements are very high; for things like air and nitrogen storage tanks, as well as cylinder banks, it’s almost necessary to stop operation in order to empty them and check the safety valves. For tanks such as ammonia tanks and Freon tanks, shut-off valves can be installed because the substances stored inside are expensive.