According to the standards of pressure gauges in my country, the threads of the pressure gauge joints are all metric threads and should meet the requirements in the following table.
Nominal shell diameter/mm Thread size Thread length/mm
40 M10×1 10
50,60 M14×1.5 14
100,150,200,250 M20×1.5 20
Since my country's reform and opening up, in addition to the various pressure measurement units of the imported pressure gauges on the production process equipment, the connection threads of the pressure gauge joints are also diverse. In addition, among the millions of pressure gauges that my country exports every year, the pressure gauge connection threads required by foreign companies are rarely metric threads. The same kind of thread is used. The pressure gauge thread codes of China, Japan and the United Kingdom are different. Just like 55° 1/4" tapered pipe thread, the code in the old standard in my country is called "ZG1/4", the code in the new standard is called "R1/4", and the code in the British standard is also called "R1/4" , And the code in the Japanese standard is "PT1/4". The following table lists the Chinese and foreign code pairs of several commonly used connecting threads.
Thread name Old Chinese standard New Chinese standard International Japan U.S.
Metric ordinary thread (60°) M14 M14 M14 M14
Cylindrical pipe thread (55°) G1/4 G1/4 G1/4 PF1/4
55° tapered pipe thread ZG1/4 R1/4 R1/4 PT1/4
60°taper thread Z1/4 NPT1/4 NPT1/4 NPT1/4 NPT1/4
