Comparison Table Of Valve Pressure Class

The Valve Common Pressure Unit Conversion Formula: 1 bar=0.1 MPa=1 KG=14.5 PSI=1kgf/m²

The nominal pressure (PN), the Class American standard pound (LB), are all one kind of expression method of pressure, the difference is, they represent to bear the pressure corresponding to the reference temperature is different, the PN European system is referred to the corresponding pressure at 120 °C, the CLass American standard refers to the corresponding pressure at 425.5 °C.

Therefore, in the engineering interchange cannot be simply converted to pressure, such as CLass300 # should be only converted to the pressure of 2.1 MPA, but if the use temperature is taken into account, the corresponding pressure has increased The equivalent of 5.0 MPA was determined by the temperature and pressure test of the material.

There are two kinds of valve systems: one is Germany (including China) represented by room temperature (China is 100 °C, Germany is 120 °c) of the allowable working pressure as the benchmark “nominal pressure” system. One is represented by the United States to a certain temperature allowable working pressure on behalf of the “temperature pressure system. “.

The temperature and pressure system in the United States is based on 454 °C at all levels except 260 °C at 150 lb. 25 Carbon Steel Valves of class 150 PSI 1MPA have allowable stress of 1 MPA at 260 degrees and a much greater allowable stress of about 2.0 MPA at room temperature.

Therefore, generally speaking, American Standard 150 LB corresponds to the nominal pressure rating of 2.0 MPA, 300 lb corresponds to the nominal pressure rating of 5.0 MPA and so on. Therefore, it is not easy to change the nominal pressure and warm pressure levels according to the pressure transformation formula.

In addition, in the Japanese standard, there is a “K” system, such as 10K, 20K, 30K, and so on. The concept of this pressure system is the same as that of the British pressure system, but the unit of measurement is metric.

Because the temperature datum of the nominal pressure and the pressure grade are different, there is no strict correspondence between them. See Table for a rough correspondence between the three.