INTRODUCTION

  • Ball valve consists of a body which houses a rotating ball with an orifice or bore machined directly through it.
  • Ball valves are durable and usually work to achieve perfect shutoff even after years of disuse. They are therefore a tremendous choice for shutoff applications.
  • Most ball valve operations are of the quick-acting type, such as lever and hand-wheel which require a 90o turn of the valve handle to operate the valve.
  • Ball valves are to be versatile due to the wide range of size (1/2” to 30”) with 150# to API 10K pressure rating class.
    • Ball valves also are available in all kind of end connections which are, Flat Face Flanged
    • Ring Type Joint Flanged
    • Raised Faced Flanged
    • Socket Weld
    • Threaded
    • Butt Weld
    • Hub

TYPE OF BALL VALVES

Floating Ball Valve

For the floating ball valves, the ball is freely to move along the axis of the valve while restricted to rotate against the stem. When line pressure is applied to the closed ball, it moves slightly downstream to maintain contact with the downstream seat where primary sealing occurs.

Trunnion Ball Valve

Trunnion Design is simply the use of upper and lower supports to retain the ball under high pressure. Trunnion mounting is used on larger valves, as it can reduce the operating torque to about two-thirds of that provided by a floating ball.

OPERATION

  • Rotation of the ball through 90° opens and closes the valve and allows fluid to flow directly through the orifice.
  • In the closed position, the blank sides of the ball block the inlet and the outlet preventing any flow.
  • Ball valve is categorized in a quarter turn valve which means it only requires 90° rotation to open or close the valve.
  • The handle that is attached to the ball is in-line with the axis of the pipe when the valve is open and conversely, if it is at right angles to the pipe axis, this indicates that the valve is closed.
  • Seating is accomplished by the eccentric movement of the plug. The valve requires no lubrication and can be used for throttling service.

APPLICATION

  • Ball valves are applicable in the piping system of the light structure, low pressure difference, and corrosive media.
  • In the fields of petroleum, petrochemical, chemical, power, and urban construction, ball valves with metal to metal sealing can work in the pipeline system with temperature above 200 ℃