How to handle check valves during pipeline purging before operation
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How to handle check valves during pipeline purging? This post was last edited by chinazwr on 2009-3-14 21:29]
If it is in the direction of the check valve, there is no problem. If it is against the direction of the check valve, it can be modified by adding a bypass at the check valve.
A short circuit can be used as a substitute; the flange for this short circuit can be made from iron plate by oneself in order to save costs. If it is not removed, debris such as welding slag can easily damage the sealing surface.
During pipeline purging, for check valves, the valve core can be removed before proceeding with the purging. In this way, Ko can avoid damage.
It is best to remove it and replace it with a temporary spool to prevent damage to the check valve during purging.
It is best to remove the check valve during purging and replace it with a bypass. If it is a threaded connection, it can be removed at the joint and a pipe with the same diameter can be threaded.
Remove the check valve spool; this is a simple and effective method. If a non-removable check valve is present, it should be removed and a short connecting tube used instead.
I think it’s better to remove it after all. It’s a bit of a hassle, though.
Method 1: Remove the short-circuiting device. Method 2: Reverse the direction of the check valve, and restore it after purging! :)
What type of check valve? Based on my experience, no matter what type of check valve it is, it’s best to remove it before purging. To prevent impurities from damaging the sealing surface during purging, attention must also be paid to the direction of purging. The easiest way is to remove it and add a flanged jumper.
During pipeline purging, valves, flow meters, check valves, and other components installed on the pipeline should be removed if possible, to avoid damage. After removing it, connect it with temporary pipes. If it is truly impossible to remove it, then find a way to take off the vulnerable components such as the valve core before performing purging.
For flange connections, it is possible to disconnect at the inlet or to replace the section downstream. If welding is used, then blow in the proper direction, without having to worry about removing the valve core; make sure the pipeline ahead is as clean as possible
If it is in the direction of the check valve and the pressure is sufficient to push the check valve open, then there is no need to disassemble it; otherwise, if it is in the reverse direction or the pressure is not enough to open the check valve, it needs to be disassembled and replaced with a bypass
1. During pipeline purging, all fittings on the pipeline, including valves, flow meters, orifice plates, thermometers, pressure gauges, etc., should be removed. 2. At the flange joint in front of the valve (or orifice plate flow meter and other fittings connected by flanges), protective measures should be applied at that joint; after purging, the connections should be reestablished and the valve should be opened to control the flow of gas for purging the subsequent sections of the pipeline.
It is highly recommended to remove the check valve and use short pipes for connection; the material of these short pipes must be of suitable quality. Flanges can be temporarily made by cutting thick steel plates, but they must be fully welded, and the material used for the pipelines must not be of lower quality than what is specified.