Low pressure reducing valve

11.7.2011 | For certain period you can find in our offer special group of low pressure regulators, which we pointed out also in our newsletters. It is self acting regulators for low pressure range. Today we would like to familiarize you with one of the available types and pointed to its specifications, advantages and possible uses.

Low pressure inline reducing valve ZM-R series is designed for automatic control of outlet pressure (P2). It consists basically of plug valve (1), pneumatic actuator (2), spring element (3) and other supplementary parts. The Control work independently, requires no power or control system.

What distinguishes this unit from other self-acting regulators is the output pressure setpoint range of 2..520 mbar (for negative pressure design: -850..+5 mbar). The function principle is shown on Figure. One side of actuator diaphragm is connected to controlled area pressure. Opposite side is under the reference pressure (usually the ambient atmospheric pressure) + spring force, which makes the setpoint of overpressure against the reference value.

The main demands are placed on manufacturing precision, which allows stable and precise control of output pressure in that range. The quality is declared also by CERN certificate for use in applications of the European Organization for Nuclear Research.

Application:
Low-pressure regulators are specially designed for use in chemical, pharmaceutical or food industry, but their use is virtually universal. Typical application is the inerting or blanketing the production areas or storage and technological tanks. In this case the main objective is to prevent the intrusion of ambient air into controlled space. Ambient air is the source of contamination, contained atmospheric oxygen in turn makes the risk of explosion or degradation of substances by oxygenation.

The valve is connected to the source of inerting gas with common pressure and maintain on his output the set overpressure against the reference. Automatically responds on operational changes of output pressure (change of medium level, pressure change with temperature change...). Regulator must be properly designed, of course, especially with regard to the maximum flow rates, such as when empty the tank to prevent tank collapse due to inadequate gas supply. In this application, the regulator cooperates with another low pressure valve on the exhaust gas from the space, which works in a relief (drain) mode and controls a constant pressure at its inlet.

The pressure setpoint can be also actively changed (linearly or in steps). In such applications the connection into the ambient air is blinded and the reference pressure is than controlled externally via the special connection. Typical use is for empty the tank "without the pump" by increasing the pressure of inert gas above the medium level.

As already mentioned, the use of the controller is a universal and together with our partners we apply it to applications in virtually all areas of industry.

Specification:

    Dimensions DN 15, 25, 50, 100
    Inlet pressure
    max 16 bar
    Outlet pressure (controlled)       
    2..250 bar/2520 for dome loaded type
    -850/220 .. +5 bar for negative pressure type
    Temperature
    -30 .. +180 °C
    Material
    Stainless steel, Hastelloy C
    other
    ATEX certificate, CERN approval ...

     

    If you are interested in those issues, please contact with questions on info@polnacorp.eu, or contact us directly by phone +420 558 321 088.


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