What problems should be paid attention to in the installation of regulating valve

Regulating valve is also known as Control Valve. In the field of industrial automation process control, it accepts the control signal output by the adjustment control unit and uses power operation to change the final control element of the process parameters such as medium flow, pressure, temperature, and liquid level. Generally composed of actuators and valves. Whether it works normally or not is directly related to whether the production of the entire device is normal or not. At present, with the rapid development of control valve technology, there are many manufacturers and forms of control valves, and their functions are also different. What problems should be paid attention to in the installation of control valves?
What are the specific problems that should be paid attention to in the installation of the control valve:
1. Incoming inspection before installation of control valve
 
    The purchase inspection of the control valve is a very important link to confirm whether the arrival of the control valve meets the design requirements. Each technical requirement of the control valve should meet the design requirements, but the following items should be checked during the incoming inspection:
 
    1. Valve body/trim specifications. This content mainly includes: valve model, valve type, nominal diameter, valve seat size, valve core form, flow characteristics, leakage level, valve body material, valve core material, valve seat material , CV value, flange standard grade size and sealing surface form, etc., as long as there is one content inconsistent with the design, it shall be determined and approved by the design.
 
    2. In the actuator part, this item should mainly check the actuator model, type, action form, spring range, air supply pressure, etc.
 
    3. Locator section This content mainly checks the input signal, air source pressure, electrical and air source interface size and explosion-proof level of the positioner. The explosion-proof level shall not be lower than the design level requirement.
 
    4. Accessories Carefully clean up various accessories according to the design and technical requirements of the regulating valve, such as Filter pressure reducing valves, valve position switches, solenoid valves, handwheel mechanisms, and special tools. The inspection of the above contents can be achieved by cleaning, measuring instruments, checking the nameplate and special detection methods (such as flange and bolt materials can be identified by spectral analysis) and other methods.

  Second, the monomer adjustment of the regulating valve
 
    The newly installed pneumatic control valve should be individually adjusted before installation. Performance indicators that should be achieved during the adjustment: Basic error: ±1.5% Return error: 1.5% Insensitive area: 0.6% Nowadays, there are many manufacturers of throttle valves and Electric Valve positioners with different functions. Electric valve positioners tend to Due to intelligence, the specific adjustment methods are different, so I won’t repeat them here.

 Third, the linkage test of the control valve
 
    After the control valve is installed, the linkage test must be carried out before the device starts. The linkage test should focus on the following points:
 
    (1) The process pipeline must be strictly purged and qualified before the control valve linkage test. It is strictly forbidden to install the control valve on the unqualified pipeline because the residue in the pipeline such as welding slag, dust and other hard debris will damage the valve core Sealing surface with valve seat.
 
    (2) Before linkage, the Butterfly Valve should be checked that both ends of the valve should not be equipped with pressure test or plugging blind plates.
 
    (3) For regulating valves with handwheel mechanism, the handwheel mechanism should be in the "release" position. Check whether the air supply pressure of the pressure reducing valve meets the air supply requirements of each regulating valve.