Installation principle of pneumatic control valve and electric control valve

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Dec 08,2022

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Installation principle of pneumatic control valve:

1. The installation position of pneumatic control valve shall be at a certain height from the ground, and a certain space shall be reserved up and down the valve to facilitate the disassembly, assembly and repair of the valve. For the regulating valve equipped with pneumatic valve positioner and hand wheel, it must be convenient for operation, observation and adjustment.

2. The regulating valve shall be installed on the horizontal pipeline and perpendicular to the pipeline from top to bottom. Generally, it shall be supported under the valve. For special occasions, when the regulating valve needs to be installed horizontally on the vertical pipeline, the regulating valve shall also be supported (except for small-diameter regulating valve). During installation, additional stress on the regulating valve shall be avoided.

3. The operating ambient temperature of the regulating valve shall be (- 30 -- + 60) and the relative humidity shall not be greater than 95%

4. There shall be a straight pipe section at the front and rear positions of the regulating valve, and the length shall not be less than 10 times of the pipe diameter (10d), so as to avoid that the straight pipe of the valve is too short to affect the flow characteristics.

5. If the diameter of the regulating valve is different from that of the process pipeline, the reducing pipe shall be used for connection. When installing small diameter regulating valve, threaded connection can be used. The fluid direction arrow on the valve body shall be consistent with the fluid direction.

6. Bypass pipe shall be set. The purpose is to facilitate switching or manual operation, and the regulating valve can be overhauled without stopping.

7. Before installing the regulating valve, completely remove the foreign matters in the pipeline, such as dirt, welding slag, etc.

Installation principle of electric control valve:

1. The installation position, height and inlet and outlet direction of the valve must meet the design requirements, and the connection shall be firm and tight.

2. The valve can be connected to the pipeline with various ends. The most important connection methods are thread, flange and welding connection. During flange connection, if the temperature exceeds 350 ℃, due to bolts. For creep relaxation of flange and gasket, high temperature resistant bolt material shall be selected.

3. The valve must be visually inspected before installation, and the valve nameplate shall comply with the provisions of the current international standard gb12220 general valve marks. For valves with working pressure greater than 1.0MPa and cut-off effect on the main pipe, strength and tightness tests shall be carried out, and they can be used only after they are qualified. Other valves may not be tested separately and shall be inspected in the system pressure test.

4. During the strength test, the test pressure shall be 1.5 times of the nominal pressure, and the duration shall not be less than 5min. The shell and packing of the valve shall be free of leakage.

5. During the tightness test, the test pressure is 0.3MPa, and the test pressure shall remain unchanged during the test duration. The time shall comply with the provisions of Table 2, and it is qualified if there is no leakage on the sealing surface of the valve disc.

6. Nominal diameter: dn15-500

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