HGT 21581-2012 Installation Manual for Automatic Control – Instrument Interface Design
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As shown in the diagram, why are so many options limited to NPT-type interfaces? Why does the catalog not provide options for M metric threads?
It may be because the NPT-type interface is more commonly used in some ** and regions, while the M metric thread interface is more commonly used in other ** and regions. Furthermore, the catalog may be determined based on design requirements and operating conditions; if only NPT-type connections are required under those conditions, then the M metric thread option will not be included. .
Leaks are likely to occur with gaskets, but NPT connections do not leak; for NPT connections, use liquid sealant or wrap them with a few turns of tape – although it’s not necessary to do so.
We use decades of results, which are the opposite of what you said
This post was last edited by Ai Shang God on 2023-4-11 at 13:37. Gaskets made of red copper that have not been properly annealed are prone to leaking. If the PTFE gasket is too thick or too thin, it is also prone to leakage. For NPT threads, even those used at low pressures leaked; wrapping them with tape didn’t prevent leaks either. It was only after applying Loctite sealant that the leaks stopped. It may be related to the manufacturer’s process for producing NPT threads. .
NPT is designed to be used in conjunction with American standards; NPT threads and G threads can be interchanged for the 1/2 size. The GB series generally uses G threads or R threads. In fact, flange connection is recommended for use under high pressure; this standard merely provides reference diagrams for installation series
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