SOR Vertical Displacer Top Mounted Series Level Switch - Manual (Page 3)

Form 425 (08.12) ©2012 SOR Inc. 3/16
Operation
 Displacer controls offer alternate features to the float-operated control. The sensor is a
weight (displacer), heavier than the liquid, which is suspended by a spring.
 When liquid contacts the displacer, a buoyancy force is produced, which causes the
effective weight of the displacer to change. This causes the spring to retract slightly to a
new equilibrium position.
 When the spring retracts, the attraction sleeve also moves upward into the field of
the external magnet, thus overcoming the force of the bias spring and actuating the
switching element. The switching mechanism operates the same as with vertical
float-operated level switches.
Displacer-Operated Level Switches - Vertical
Deactuated
Actuated
Switching Element
Common
Normally Open
Normally Closed
Pivot
Bias Spring
Magnet
Attraction Sleeve
Enclosing Tube
Extension Spring
Suspension Cable
Displacer
Level Differential
Displacer-Operated Level Switches - Vertical
NOTE: This principle provides for narrow or wide switching differential, and allows switching
point alteration by moving the displacer(s) up or down the suspension cables.
NOTE: Displacers can be arranged in combinations of narrow and wide differential to operate
up to three switching stages. Displacer controls operate under higher pressure conditions
than fl oat-operated switches.