The NPT thread can seal?

Bimetallic thermometer with many different kinds of screw thread, standard is very much also. But the effect is the same, are used to connected to the measured medium equipment, at the same time in order to ensure the accuracy of measurement, the thread is another important mission must be to keep the connection part of the seal. Bimetallic thermometer on the common thread is BSP and NPT, the difference is the BSP is straight tooth, can be completely turned to the end, the NPT is a conical teeth, can only be turned to the two-thirds of the teeth, so the question comes, NPT thread can seal? About this issue, opinions vary, according to our practical application experience, in order to ensure the sealing, NPT threads need to use sealant to seal, and when the seal is strict, sealants may fail due to high temperature and high pressure. It is important to note that so everyone in the choice.