ball valves have many types
A V port BALL VALVE has either a 'v' shaped ball or a 'v' shaped seat. This
allows the orifice to be opened and closed in a more controlled manner with a
closer to linear flow characteristic. When the valve is in the closed position
and opening is commenced the small end of the 'v' is opened first allowing
stable flow control during this stage. This type of design requires a generally
more robust construction due to higher velocities of the fluids, which might
damage a standard valve.
A trunnion ball valve has additional mechanical
anchoring of the ball at the top and the bottom, suitable for larger and higher
pressure valves (say, above 10 cm and 40 bars).
Cavity filler Ball
Valve. Many industries encounter problem with residues in the ball valve. Where
the fluid is meant for human consumption, residues may also be health hazard,
and when where the fluid changes from time to time contamination of one fluid
with another may occur. Residues arise because in the half open position of the
ball valve a gap is created between the ball bore and the body in which fluid
can be trapped. To avoid the fluid getting into this cavity, the cavity has to
be plugged, which can be done by extending the seats in such a manner that it is
always in contact with the ball. This type of ball valve is known as Cavity
Filler Ball Valve.
Manually operated ball valves can be closed quickly
and thus there is a danger of water hammer. Some ball valves are equipped with
an actuator that may be pneumatically or motor operated. These valves can be
used either for on/off or flow control. A pneumatic flow control valve is also
equipped with a positioner which transforms the control signal into actuator
position and valve opening accordingly.
Straight through, two way, or
three way BALL VALVES
Schematic 3 way ball valve: L-shaped ball right,
T-shaped left
Three-way BALL VALVES have an L- or T-shaped hole through
the middle. The different combinations of flow are shown in the picture.
Multi-port ball valves with 4 ways, or more, are also commercially
available, the inlet way often being orthogonal to the plane of the outlets. For
special applications, such as driving air-powered motors from forward to
reverse, the operation is performed by rotating a single lever 4-way ball valve.
The 4-way valve has two L-shaped ports in the ball that do not interconnect,
sometimes referred to as an "" port.
BALL VALVES in sizes up to 2 inch
generally come in single piece, two or three piece designs. One piece ball
valves are almost always reduced bore, are relatively inexpensive and generally
are throw-away. Two piece ball valves are generally slightly reduced (or
standard) bore, they can be either throw-away or repairable. The 3 piece design
allows for the center part of the valve containing the ball, stem & seats to
be easily removed from the pipeline. This facilitates efficient cleaning of
deposited sediments, replacement of seats and gland packings, polishing out of
small scratches on the ball, all this without removing the pipes from the valve
body. The design concept of a three piece valve is for it to be repairable.
More products of valves
