The service pressure of the valve is determined by the nominal pressure PN, valve body material and service temperature.
For example: the PN16 valve body material is WCB, the service temperature is 38 degrees, and the maximum service pressure is 1.6 MPa. This is a low-pressure valve, which is the most common conventional pressure valve.
In fact, this is just the view of the valve industry, it is not necessary to distinguish it clearly.
As long as the pressure requirements put forward by the customer, we can issue drawings to him.
Valve flange thickness and valve thickness is not standardized, according to the pressure requirements.
6.4Mpa and 10MPa flange thickness and valve body thickness are completely different.
For example: the basic pressure of general low-pressure valve is 1.6Mpa, which is cast according to GB / t139272008 and JB / t90921999
Generally, 1.6Mpa is selected, and the highest pressure is 1.6×1.5 = 2.4Mpa. If the pipeline pressure exceeds this, it will not work. In addition, many manufacturers have made the valve wall thinner in order to save cost. It is a little difficult for a conventional gate valve to have a pressure of 1.6Mpa.
Valve classification by pressure:
1. Vacuum valve – a valve whose working pressure is lower than the standard atmospheric pressure.
2. Low pressure valve – the valve whose nominal pressure PN is less than 1.6Mpa.
3. Medium pressure valve – the valve with nominal pressure of PN 2.5 ~ 6.4Mpa.
4. High pressure valve – the valve with nominal pressure of pn10.0 ~ 80.0mpa.
5. Ultra high pressure valve – the valve with nominal pressure PN greater than 100MPa.
Nominal pressure PN: the reference value related to the pressure resistance of piping system components. For ease of use, the priority number of R10 series is usually taken. The nominal pressure refers to the working pressure of water delivery at the secondary temperature (20 ℃). If the water temperature is between 25 ℃ and 45 ℃, the working pressure should be corrected according to different temperature drop coefficient.
Low, medium and high is just a general statement, such as people’s height, fat and thin there is no clear distinction
At present, the design of pressure pipe fittings is specific to the pressure value. It will not be said that a medium pressure valve will be installed in this place.
Pressure pipes are generally classified in this way according to pressure, and valves can also be distinguished according to this.
Of course, if you say that 2.0 belongs to medium pressure valve, no one will investigate if it belongs to low pressure valve
According to pressure:
1. The engineering pressure of low pressure pipeline is less than 1.6Mpa;
2. The engineering pressure of medium pressure pipeline is 1.6-6.4mpa;
3. The engineering pressure of high-pressure pipeline is 6.4-10mpa;
4. The engineering pressure of ultra-high pressure pipeline is 10-20Mpa.