What are the installation specifications for the primary valve (root valve) used in instrumentation? Is the presence of threads or welded connections allowed in front of the root valve?
Thread Content
What are the installation specifications for the primary valve (root valve) used in instrumentation? Is the presence of threads or welded connections allowed in front of the root valve? It is hoped that verifiable standards can be provided. Thank you for your advice! ! reward_7ree
GB50093-2013 Code for Construction and Acceptance of Instrumentation
Screw connections are generally not used in front of a one-way valve.
\"GB 50093-2013 Code for Construction and Quality Acceptance of Automation Instrumentation Projects\" 5 Installation of sampling components 5.1.7 When installing sampling components, no holes shall be made in welds or their edges, nor shall welding be performed on those areas. 5.1.9 The connection between the sampling valve and the equipment or pipelines should preferably not use ferrule-type joints
Check the atlas, HG/T 21581-2012
Welding is definitely no problem; the catalog HG/T 21581 includes gate valves that can be welded, as well as ball valves that can be installed with flanges. I also want to ask those with threaded connections whether there are any specific regulations stating whether it is allowed or not
I also think that threaded connections generally should not be used before a valve, but I can’t find any relevant regulations or standards; please help.
Thank you. I believe threaded connections should not be used before a valve, but I couldn’t find any relevant specification requirements; please help.
The specifications do not state that the root valve must be welded; threaded connections are allowed. This is likely because other factors are taken into account, such as the installation of instruments with low pressure and non-toxic media, in which cases threaded connections are also acceptable. Besides that, for safety reasons, I also prefer to use welding.
If it can be welded, why use threads? There’s energy with no place to go, or maybe it’s just from overeating.
When connecting process equipment, pipelines, and instrument root valves (also known as primary valves), the main consideration is the risk of leakage, as a leak can only result in the shutdown of the process. Therefore, welding or flange connection is generally used.