What Is A Linear Control Valve ?

Linear control valve, also known as 4-20mA control valve, is used to accurately control temperature or pressure or main flow, so it also has a few other names such as:

Temperature control valve

Pressure control valve

Flow control valve

Two types of industrial linear valves – KFM / Germany linear control valves:

  1. Pneumatic linear valve

Pneumatic linear control valve operates on the supply of compressed air to the valve’s Actuator. To do this, the controller, also known as the Positioner, must have very high accuracy.

  1. Electric linear valve
  • The electric linear control valve has the advantage that it only needs to be supplied with a 220V / 24V source with a control signal of 4-20mA / 0-10V to make it work. While the pneumatic control valve is required to have a stable source of compressed air.Advantages and disadvantages of electric and pneumatic control valvesA disadvantage of electrically controlled valves is that the running time of a stroke is quite slow, so systems with fast temperature changes must choose a pneumatic control valve.

    Some areas do not have a source of compressed air, forcing us to choose an electric control valve, but if we need a fast response time, we should choose the option of a fast response time. With this option, the valve will run about 30% faster than standard.

    Compare the advantages and disadvantages of pneumatic linear valve and electric linear valve

    Pneumatic linear control valve Pneumatic linear control valve
    ·       Fast response time

    ·       Precise control

    ·       Requires a compressed air source

    ·       Control signal 4-20mA / 0-10V

    ·       Fast response time

    ·       Precise control

    ·       Requires a compressed air source

    ·       Control signal 4-20mA / 0-10V


    1. Select control valve:


    With the design of each type of control valve in each different application, we choose the pneumatic linear valve or the electric linear valve accordingly.

    Technical parameter of linear control valve KFM – Germany

    Linear control valve sizes from DN15, DN25, DN32, DN40, DN50, DN65, DN80, DN100, DN125, DN150, DN200, DN250.

    Withstand pressure of linear control valve from PN16, PN25, PN40.

    The working temperature of the linear control valve is from 250oC to 350oC.

    Leakage level < 0.01% of the total flow through the valve.

    Materials have many types from: Cast iron, Alloy steel, 316L stainless steel …

    Time to open and close the valve from 3-5s depending on the pressure and valve diameter.

    The service life of KFM linear control valve is from 3-10 years depending on the actual application needs.

    Control signal: 4-20mA and compressed air supply from 1.6…6bar


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