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General Requirements for Control Valve Installation

General Requirements for Control Valve Installation

2020-09-29

Control Valve Installation

Check before installation of the control valve

1.1 Before installing the control valve, check whether the product qualification certificate, installation, and operation instructions of the control valve are complete.

1.2 The control valve should be visually inspected before installation and should meet the following requirements:

a) The outer surface must not have defects such as cracks, blisters, mechanical damage, rust, dirt, etc.;

b) The nameplate must not fall off, and the technical parameters on the nameplate conform to the system design requirements;

c) Both ends of the control valve should be protected by protective covers;

d) There should be no defects such as water accumulation, rust, dirt and damage in the valve body;

e) There must be no paint on the thread of the threaded connection, the thread must be intact, the flange sealing surface must not have any damage that affects the sealing performance such as radial grooves, and the welding end bevel is intact, and there should be no mechanical damage that affects the welding;

f) The inner surface of the valve body with rubber lining, porcelain lining, and plastic lining should be flat and smooth, and the lining layer and the base body should be firmly combined, and there should be no defects such as cracks and blisters.

1.3 The opening and closing inspection of the control valve and the hydraulic test The control valve (except the safety valve) should be flexible in opening and closing, and the position indicator should be accurate. Before installation, manually switch the control valve three times to check whether there is jamming.

Control valves (except safety valves) have been shipped for more than one year. Pressure tests are recommended under conditions. Control valves for petrochemical and related industries are tested in accordance with the regulations of JB/T9092, and general industrial control valves are tested in accordance with GB/T13927. Regulations proceed.

2.1 General requirements for control valve installation

2.1.1 Read the installation manual carefully before installing the control valve.

2.1.2 Control valves with specified flow direction should be installed in accordance with the specified flow direction of the control valve.

2.1.3 Under normal circumstances, do not install the control valve handwheel downwards to avoid corrosion of the valve stem.

2.1.4 The installation position of the control valve should be convenient for operation and maintenance.

2.2 When carrying and lifting the control valve, the lifting rope should not be tied to the handwheel or valve stem, but should be tied to the lifting lug or flange of the control valve. When carrying, the handwheel or handle should not be used as a handle.

Connection of control valve

2.3.1 According to the connection form of the control valve, select the connection form on the pipe side. The flange and thread of the pipeline should be the same as the standard of the control valve.

2.3.2 The pipes connected to the control valve should be cleaned to avoid damage to the sealing surface of the control valve by iron filings, silt, welding slag, and other debris.

2.3.3 When installing the threaded connection control valve, seal packing (line hemp plus lead oil or polytetrafluoroethylene raw material tape) should be wrapped on the external thread to prevent the valve from accumulating and affecting the medium flow.

2.3.4 When installing the flange control valve, pay attention to symmetrically and evenly tighten the bolts. The flange of the control valve and the pipe flange must be parallel with reasonable clearance to avoid excessive stress on the control valve. Special attention should be paid to the control valve with brittle materials and low strength.

2.3.5 The welding connection should be constructed in accordance with the welding procedure qualified for welding procedure, to avoid welding slag and other debris from entering the pipeline. After the control valve is welded to the pipeline, a non-destructive inspection of the weld shall be carried out as required.

2.4 Gaskets and gaskets should be selected reasonably according to the requirements of flange form, pressure level, temperature, and medium.

2.5 The driving device is connected to the control valve of the driving device. The electrical, pneumatic, and hydraulic pipelines should be connected according to the wiring diagram or piping diagram in the manual. Confirm the correctness of the wiring before connecting.

2.6 The installation foundation of the control valve with foot support should be stable.

2.7 Special requirements

2.7.1 For control valves that require external heat preservation and cold preservation, the construction of the protective layer should be completed before the medium is introduced.

2.7.2 When installing the safety valve, pay attention to the position of the discharge port and avoid facing the operator.

Adjusting valve after installation

3.1 Preparation before commissioning Before system commissioning, the control valve, and the pipeline should be subjected to a hydraulic test, and commissioning can be carried out only after being qualified. Check for leaks at each connection. Special control valves should be specially specified.

3.2 Electric control valve motor test operation control method In the local control state, manually adjust the valve to the middle position, carry out the motor test run, turn on the on or off button and stop immediately, check whether the switch direction of the electric control valve is in accordance with the switch indicator and The rotation direction of the control valve itself is the same, otherwise, the phase sequence check or wiring adjustment should be carried out.

3.3 Limit switch setting

3.3.1 The general limit switch is set at the factory and no further adjustment is required.

3.3.2 Debugging off-limit setting. Manually adjust the valve to the closed position, and then turn it back 1 to 2 times. Use a screwdriver and other tools to adjust the limit switch to the closed position. The limit switch just moves. Use a multimeter to measure the limit switch. The output contact signal should be correct.

3.3.3 Debugging open limit setting method is the same as above.

3.4 The input of the control signal of the electric and electromagnetic control valve must meet the requirements of the drive device.

3.5 The pressure source pressure of pneumatic and hydraulic control valves should meet the requirements of the drive device.

4.3.6 The control valve shall be adjusted together with the system to check the action and function of the control valve.


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