Principle Of Operation - Emerson Fisher L2e Instruction Manual

Instruction Manual
D103531X012

Principle of Operation

The operation of the L2e is based on Archimedes Principle, which states that a body immersed in a liquid will be
buoyed up by a force equal to the weight displaced. The buoyant force and resultant movement of the displacer in the
liquid is transmitted to the controller. As the buoyant force changes a proportional change in movement is seen by
levers A and B (refer to figure 7). Levers A and B are arranged and connected by movable pivot or span adjustment so
that the resultant movement between the plunger and the switch can be adjusted. For a given change in displacer
movement the span adjustment will increase or decrease a proportional change in the plunger movement. As fluid
level rises, the plunger moves away from the switch and vice versa.
Figure 7. Fisher L2e Controller
CONTROLLER MOUNTING
SCREWS (KEY 24)
DISPLACER
ROD (KEY 64)
ZERO SPRING
(KEY 7)
ZERO ADJUSTMENT
ZERO ADJUSTMENT
HEX NUT (KEY 5)
GG10047
w/Displacer Rod
LEVER A
PLUNGER
FACTORY SET - DO NOT ADJUST
L2e Controller
May 2017
SPAN
ADJUSTMENT
LEVER B
SWITCH
11