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Oil, gas and petrochemical process industries


    VALVE PARTS

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    Talib Al_Munawri
    Director-General
    Director-General

    Posts : 337
    Join date : 2009-07-03
    Age : 30
    Location : Sultanate of Oman

    VALVE PARTS

    Post by Talib Al_Munawri on Thu Sep 17, 2009 9:16 pm

    VALVE PARTS






    Major parts common to most valves are as follows:


    Arrow Body.
    Arrow Valve Disc (Opening Element).
    Arrow Stem.
    Arrow Handwheel / Handle.
    Arrow Bonnet.
    Arrow Packing Gland


    BODY

    The body is the part of a valve that is attached to the pipework
    flange. The gases or liquids flow through the body when the valve
    is open.


    VALVE DISC (OPENING ELEMENT)

    This is the part that opens and closes the valve. All valves have
    a valve disc in the valve body. Valve discs are made in various
    shapes and sizes. They can move up and down with the stem, or rotate around a central pivot point.

    The valve disc stops or allows flow through a valve. We will discuss
    types of valve disc further when we look at different types of
    common valves. When the valve is closed the valve disc fits against
    the valve seat.


    STEM

    The stem raises or lowers the valve disc. In manually operated
    valves the stem is usually threaded. In ball valves and butterfly
    valves the stem does not move up or down. It turns inside the
    bonnet. In pneumatic and hydraulic valves the stem is a smooth rod
    that moves up and down in the valve body.



    HANDWHEEL / HANDLE

    On a manual valve a handwheel or handle is attached to the stem.
    The handwheel or handle allows the operator to turn the stem.
    The handwheel is held on the stem by a handwheel nut.


    BONNET

    The bonnet is a separate housing that is bolted tightly to the top
    of the valve body. The stem passes through the bonnet.
    The bonnet holds the stem in position.


    PACKING GLAND

    The packing gland is held in place by bolts or sometimes it is
    screwed into place. This gland keeps the packing tight. Packing
    is a soft material inside the bonnet placed around the stem to make
    a tight seal. The packing stops pressurised gas or liquid in the
    valve from escaping to the atmosphere.


      Current date/time is Tue Aug 22, 2017 9:50 pm