Valve nominal pressure

The reference value related to the pressure resistance capacity of piping system components refers to the design given pressure related to the mechanical strength of piping components. The nominal pressure is generally expressed by PN.

Nominal pressure PN is a numerical designation code related to pressure, which is a convenient round integer for reference. All pipeline accessories of the same nominal diameter indicated by the same nominal pressure PN value have the same connection size that is compatible with the end connection type.

PN16 represents the nominal pressure of 1.6MPa. PN, nominal pressure (Nominal Pressure), is a method of expressing pressure; it is mainly used for the pressure expression of shell equipment such as pipes, pipe fittings, valves, etc.
Nominal pressure PN is a numerical designation code related to pressure, which is a convenient round integer for reference. All pipeline accessories with the same nominal diameter indicated by the same nominal pressure PN value have the same connection size that is compatible with the end connection type.
The determination of the nominal pressure of the flange is related to the maximum operating pressure, operating temperature and flange material of the flange. Because the mechanical properties of Q345R at 20 °C are used as the benchmark when formulating the flange size series and calculating the flange thickness, it is stipulated that the flange size determined by this benchmark is at 20 °C, and its maximum The allowable operating pressure is considered to be the nominal pressure of the flange with that size. For example, a flange with a nominal pressure of PN0.6MPa refers to a flange with such a specific size. The flange is made of Q345R, and its maximum allowable operating pressure is 0.6MPa at 20°C. If this PN0.6MPa flange is used at a temperature higher than 20°C, its maximum operating pressure will be lower than its nominal pressure by 0.6MPa. On the contrary, if it is used under the condition of lower than 20℃, its maximum working pressure is still determined according to 20℃. If the material of the flange is changed to Q235A, the mechanical properties of Q235A steel are much worse than that of Q345R. This flange with a nominal pressure of PN0.6MPa, even if it is operated at 20℃, its maximum allowable operating pressure will be lower than its nominal pressure. On the contrary, if the material of the flange is changed from Q345R to 14Cr1MoR, then, since the mechanical properties of 14Cr1MoR are better than that of Q345R, the maximum allowable operating pressure of this flange with a nominal pressure of PN0.6MPa will be higher than its nominal pressure. In short, the maximum operating pressure allowed by the flange depends on the operating temperature of the flange and what material it is made of. The flange material specified in the pressure vessel flange standard is Q235R, Q245R, Q345R, etc. At different temperatures, the conversion relationship between their nominal pressure and the maximum allowable working pressure can be used to compare the operating temperature given in the design conditions with the design The pressure is converted into the nominal pressure required to obtain the flange standard.

(1) Vacuum valve: refers to the valve whose working pressure is lower than the standard atmospheric pressure.

(2) Low pressure valve: refers to the valve with nominal pressure PN ≤ 1.6Mpa.

(3) Medium pressure valve: refers to the valve with nominal pressure PN of 2.5Mpa, 4.0Mpa and 6.4Mpa.

(4) High pressure valve: refers to the valve whose nominal pressure PN is 10.0Mpa～80.0Mpa.

(5) Ultra-high pressure valve: refers to the valve with nominal pressure PN ≥ 100.0Mpa.

The working pressure of the valve generally refers to its nominal pressure.
Nominal pressure PN (0.1MPa): The reference value related to the pressure resistance capacity of the piping system components. For ease of use, the priority number of the R10 series is usually taken. Nominal pressure refers to the working pressure of the pipe for water delivery at the secondary temperature (20°C). If the water temperature is between 25°C and 45°C, the working pressure should be corrected according to different temperature drop coefficients.

1. Different meanings

The nominal pressure is also the nominal pressure, that is, the design pressure, that is, the maximum allowable pressure of the valve. Generally speaking, it is the value after the design pressure is rounded. Indicates the compressive strength of the product at the reference temperature.

Working pressure is the pressure that the valve needs to withstand under normal working conditions. Indicates the pressure to which pipes and fittings are subjected under normal conditions.

2. Different units

The nominal pressure is expressed in PN, and the unit is MPa.

The working pressure is represented by P t.

3. Different temperature

Nominal pressure reference temperature: Different materials have different reference temperatures. For example, the reference temperature for steel is 250°C.

Working pressure: t × 10 = maximum working temperature of the product.

4. Different sizes

PN > P t, the nominal pressure is greater than the working pressure.

PN full name (pressure nominal) means the nominal pressure unit is MPa. For example, the nominal pressure of J41H-16C is 16Kgf/cm2, that is, the pressure value per square centimeter is 16Kg. If it is calculated in MPa, it is PN1.6MPa. DN means that the internal diameter unit of the pipeline is mm mm such as DN50 is

PN full name (pressure nominal) stands for nominal pressure

The unit is MPa MPa

For example, the nominal pressure of J41H-16C is 16Kgf/cm2

That is, the pressure value per square centimeter is 16Kg, if it is calculated in MPa, it is PN1.6MPa

DN stands for the inner diameter of the pipe

The unit is mm

For example DN50 is 50mm

The fractional valve is to express the inner diameter of the pipe in inches

1 inch = 2.54 cm

DN15——1/2″

DN20——3/4″

DN25——1″

DN32 – 1 1/4″

DN40——1 1/2″

DN50——2″

DN65——2 1/2″

DN80——3″

PN is the pressure, and PN40 means that the use pressure is 40 kilograms per square centimeter.

pn25 is equal to 2.5MPa. MPA is pressure in megapascals. 1 standard atmosphere equals 0.1MPa equal to 760mmHG mercury column, 1 atmosphere equals 1.03323kg per cm2 of pressure. 1MPA is equal to 10 atmospheres of pressure equal to 10.3323kg per cm2, which is equivalent to 10.332 kg per square centimeter of pressure.

No the same. PN10 and PN16 cannot be used in common,
Because of different pressure tolerances,
Unless PN10 is replaced by PN16, it is replaced by high and low.
Because the outer diameter is the same,
Needs to be beveled.

Body pressure rating is the static rating of the body and stem (housing), which is the total amount of pressure the body and stem can hold without leaking.

When the valve controls a certain range of internal pressure to a certain value, it is called the valve rated pressure. The higher the pressure rating of the valve, the thicker the wall thickness, so the valve parts will not be damaged. The rated pressure is also affected by the operating temperature. The higher the process temperature, the lower the pressure the valve body components can withstand. Use ANSI Standard B16.34 to determine the pressure-temperature relationship, as well as the applicable wall thickness and end connections. It is important to understand the commonly used pressure grade variation range and rated pressure, especially the pressure grade of the valve can be designed as standard grade, special grade and intermediate grade.