Why will be the threads G 1/8 and 1/8 NPT offered for pressures and then a nominal pressure selection of 400 bar? Where does this limit come from?
Basically, ไดอะแฟรม is simple: From a certain pressure limit, the thread flanks are no longer ?strong? enough to resist the force of the applied pressure. If the pressure is too much, there is a risk of shearing for the thread. By the way, the pressure limits come from DIN EN 837-1.
Attention: The maximum pressure around which a thread can be used depends not merely on the thread diameter, but additionally on the selected sealing type and the material of the counter-thread.