prevent product flowaround the exteriorof the ball.Thisdesignis not
suitable for mechanical cleaning techniques and requires complete
disassemblyfor manualcleaning.
∑ Cage ball valve: this is a variationof the ball valvedesign.In this design,a
solid ballis retainedin a movable cage attached to an actuator shaft.
Actuation of the valvepositionsthe looselyretained ball so that the product
pressurewithinthe valve bodycausesthe ball to block a port of the valve.
Theaction is similar to that which occurs within a ball check valve.
Fig. 16.2 Compressionvalve.Fig. 16.3 Diaphragmvalve.266 Handbookof hygiene controlin the foodindustry