Should the connection between the valve and the pipeline be made using flanges or threads?
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Should the connection between the valve and the pipeline be made using flanges or threads? How to choose?
Of course, it’s the flange connection! Threaded connections are rarely used these days (they can only be used for low-pressure water pipes).
A comprehensive consideration is necessary, including pressure rating, material, medium, as well as ease of maintenance and replacement. Flanges are widely chosen these days; firstly, they facilitate connection and make it easy to replace valves, and secondly, they prevent leakage during use and are suitable for piping systems.
Small-diameter applications such as heating and water supply/pumping systems are connected using threaded connections
For small-diameter pipes used in heating, water supply, and drainage systems (less than DN50), threaded connections are generally used, as it is relatively easy to thread such small pipes； For pipes with high pressure and large diameters, flange connections are still more appropriate.
Just check the pipeline grade table; it explains in detail what type of flanges to use for various pressure levels
Not necessarily; the safety valve of ours with a pressure rating of 150 kg is connected via threads. I hope everyone will discuss this in detail, and I’m also learning about it*
Generally, utility pipelines with a weight of less than 10 kg can be connected using threaded connections; this is applicable to systems such as water supply pipelines, where a diameter of less than 100 mm is preferred. In other cases, flanged connections are more suitable. Of course, in high-pressure situations, a combination of threaded and welded connections may be used.
For industrial use, flange connections are recommended as they are less prone to leakage
The people upstairs have explained things in quite detail; let me add a few more points. It also depends on the requirements of the manufacturing process; for example, in the case of pipeline valves for instrument air, threaded connections are used, so welding is not permissible. The reason is that the gauge components are relatively expensive and delicate; impurities in the gauge air are absolutely not allowed, to prevent damage to the components.
It depends on whether you choose a threaded valve or a flanged valve