Are there any standard specifications regarding whether gaskets should be used with the flange bolts of valves?
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Dear experts: Are there any standard specifications regarding whether gaskets should be used with the flange bolts of valves? Some valve manufacturers supply gaskets, while others do not.
The standard configuration requires flat washers and spring washers. Electrostatic bonding should be performed between the flanges
1. Washers are generally not used; they are employed only when fastening non-metallic or non-ferrous metal fittings. 2. Use shims, as there is a risk of seal failure under high temperature and pressure. 3. A high bolt preload can damage the washers, which is counterproductive.
I’ve taken a screenshot specifically to show you the regulations in HG/T20646.5.
Do foreign standards explicitly state that it is not necessary to add it?
Since 2000, our **standards have been formulated and implemented by referring to or relying on** such standards. Why 2000? It’s because in 2001, China joined the WTO. Around that time, in order to ensure consistency in foreign trade, efforts were made to organize things systematically, and standards for almost all industries were adjusted once again. The washers we use now also follow international standards. For example, the ASME standards do not specify washers for bolts, and accordingly require an increased bolt torque value.
This post was last edited by In short_myP89 on 2021-2-4 10:16
I’m still young; I’ve been exposed to a variety of things, so I only know a little bit about them
Flanges installed on-site generally do not require gaskets; however, it is recommended to use them if transportation is involved, as this can reduce the risk of loosening due to vibrations
It seems that the regulations stipulate that it shouldn’t be added, but in our designs we have it prepared for the manufacturer to include; whether it’s installed or not is decided on site