Page 146 - Valve Selection Handbook

Manual Valves 133

Figure 3-91. Pinch Valve, Fluid-Pressure Operated. (Courtesy of RKL Controls, Inc.)

Figure 3-92. Pinch Valve, Fluid-Pressure
Operated, with Iris-Like Closing Action.
The Constricting Action of the Rubber
Muscle upon the Sleeve Is Literally a 360°
Squeeze. Pressure is Evenly Applied to the
Circumference of the Sleeve—Hence the
Always Round, Always Centered Hole.
(Courtesy of /ne Clarkson Company.)

Valve Body

The valve body is made of an elastomer, PTFE, or a similar material,
or a combination of these materials. Fabric reinforcement may be used to
increase the mechanical strength of the valve body.
Natural rubber is the best construction material for the valve body
from the point of resistance to cracking from flexing. Natural rubber also
shows excellent resistance to abrasive wear and to corrosion from many
corrosive fluids.