Issues with the connection of instrument air supply pipelines
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Hello everyone, in my factory there are some gas supply pipelines; the main pipes have been welded, with TIG welding used for the root pass and MIG welding for the finish pass. The branch pipes have small tubes, in quantities of 8 or 14. I would like to know whether the regulations specify that such small tubes must be welded using TIG welding. Also, what size of pipelines should be connected by welding, swaging, socketing, etc.? Are there any clear requirements in the regulations regarding this?
If it is instrument air, stainless steel pipes or galvanized pipes should be used. Generally, pipes with a diameter of DN50 or less should be connected using threads; galvanized pipes should preferably not be welded, as this will damage the galvanizing layer and lead to instrument failures.
This post was last edited by ylb913 on 2016-1-4 at 20:23. Welding is generally not allowed; firstly, this is based on years of practical experience in the field for individuals, and Secondly, one can refer to the relevant regulations. SH/T 3020-2013 Design Code for Gas Supply for Petrochemical Instruments; HG/T 20510-2000 Regulations for the Design of Instrument Gas Supply
What is the reason why argon arc welding is required for instrument air ducts?
Why is argon welding required for the instrument air ducts? – High requirements for internal cleanliness
Blow it out a few times using the endpoint valve that was opened earlier; it’s sufficient to connect the air pipes of each pneumatic valve from the top
I don’t know about this, but I’ve seen that the gas supply pipes in many factories are welded
These days, card sleeves are used the most (they’re convenient and easy to replace)
Are you using welded steel pipes or seamless steel pipes? If welded steel pipes are used as gas supply pipes, what are the effects of welding them directly? (For example, in terms of sealing performance, etc.)
Thank you for sharing your experience! :handshake
Welded steel pipes have pressure resistance issues; generally, gas supply pipelines are made of seamless steel pipes. It doesn’t cost much more to use these, but stability is greatly improved as a result