Flow Switches for High Velocity Flows
- Under 7 FPS velocity use a standard vane
- 7 – 10 FPS use the paddle shroud
- Over 10 FPS use a high flow configuration
The Paddle Shroud design is ideal for violent flows. The paddle shroud re-enforces the stem and paddle and relieves stress concentration around the screws. Available on all models except tee styles.
The symmetrically placed perforations help reduce turbulence and cavitation. Excessive turbulence and build-up of vacuum behind the paddle is prevented.
This design utilizes a hinge-pin which allows the paddle to move through a 90° travel, swinging up to a horizontal position. It is only effective for actuation at the lower end of the flow spectrum -higher flows will disengage the bias spring. We do not recommend this unit for lines smaller than 6″ because the hinging configuration occupies the first 2″ of stem and paddle. For screwed mounting these units should be mounted only with a thread-o-Iet. For flanged mountings we recommend a minimum distance from the face of the mounting flange to the top I.D. of the pipe of 4-1/2″. This 4-1/2″ is standard; if necessary it can be increased to a maximum of 6″.
This construction is ideal for violent flows or heavy paddles. We utilize a pivot at the base of the switch, with the stem and paddle hanging on this pivot. Above the pivot, the stem ends in a socket which operates a ball attached to the upper stem.
This construction can be used for flow and reverse flow applications . For over 24″ stem extension, this design is mandatory. It cannot be used in small tees. The paddle can be a solid or hollow cylinder, perforated , bar paddle, or other special design.