Page 93 - Valve Selection Handbook

80 Valve Selection Handbook

Figure 3-34. Wedge Gate Valve Figure 3-35. Wedge Gate
with Plain Hollow Wedge, Valve with Plain Hollow Wedge,
Screwed-in Bonnet, ancflnternal Bolted Bonnet, and Internal
Screw. (Courtesy of Crane Co.) Screw. (Courtesy of Crane Co.)

There are also types of wedge gate valves that can dispense with a
wedge guide, such as the valve shown in Figure 3-45 in which the wedge
is carried by the diaphragm.
Compared with parallel gate valves, wedge gate valves also have some
negative features:

• Wedge gate valves cannot accommodate a follower conduit as conve-
niently as parallel gate valves can.
• As the disc approaches the valve seat, there is some possibility of the
seatings trapping solids carried by the fluid. However, rubber-seated
wedge gate valves, as shown in Figure 3-44 and Figure 3-45, are capa-
ble of sealing around small trapped solids.