Common instrument interface threads
Thread Content
The thread interfaces of instruments are quite complicated; different thread standards must match in order to be connected. Thread standard comparisons: 1) The British BSPP and BSP standards correspond to China’s G standard – these are used for straight pipe threads with a thread angle of 55 degrees (cylindrical tubes). 2) The British BSPT standard corresponds to China’s ZG standard – it is used for tapered pipe threads with a thread angle of 55 degrees (conical tubes). BSPT: British standard pipe thread with a thread angle of 55 degrees. 3) The American NPT standard corresponds to China’s own NPT standard – it is used for tapered pipe threads with a thread angle of 60 degrees (conical tubes). NPT: American standard tapered pipe thread, with a thread angle of 60 degrees and a taper ratio of 1:16
The taper is 1 degree 47 minutes; PT and NPT threads must not be confused with each other, as their angles are different and they cannot be used together