Valve is used to control fluid flow, pressure and flow devices. Is to control the fluid can be a liquid, gas, gas-liquid mixture or liquid mixture, Valves are usually made up of body, bonnet, seat, hoist parts, drive mechanism, seals and fasteners and other components, Control valve drive mechanism is to rely on parts or fluid driven lifting hoist, sliding, rotating or turning motion put to the size of change in flow area to achieve.

    Valve is so widely used, it is with people