T E C H N O L O G Y
Operation is based upon simple buoyancy, whereby a
spring is loaded with weighted displacers which are
heavier than the liquid. Immersion of the displacers in
the liquid results in buoyancy force change, which
moves the spring upward.
displacer, spring movement
is always a small fraction
of the level travel between displacers
.
A magnetic sleeve
is connected to the spring and
operates within a non-magnetic barrier tube
.
Spring
movement causes the magnetic sleeve to attract a pivot-
1
4
3
Return
Spring
5
6
Pivot
Since the spring moves only when the level moves on a
ed magnet
,
actuating a switch mechanism
located
outside the barrier tube. Built-in limit stops prevent over
stroking of the spring, under level surge conditions.
Rising
Level
2
Falling
Level
P R O O F - E R
C O N T R O L S
the switch actuator simulating a high or high-high level
condition. When the chain is released, the PROOF-ER
returns the actuator to its previous position to resume nor-
mal operation.
The purpose of the PROOF-ER is to check the operation
of a displacer control without having to raise the level in
the tank. This is accomplished by pulling downward on
the PROOF-ER chain. A spring-loaded lever arm then lifts
F L O A T I N G
R O O F T O P
C O N T R O L S
A hollow brass displacer is required if the control is to
actuate in liquid as well as by the barrier. Consult factory
for other options.
The floating rooftop control is designed for installation on
“barrier” (floating roof) tanks. The control will be fur-
nished with a brass weight displacer to prevent sparking.
D I S P L A C E R S
Stainless steel displacers are rated 720 psig @ +100° F
(50 bar @ +38° C).
Karbate displacers are limited to a minimum temperature
of +32° F (0° C) and a maximum temperature of +300° F
(+149° C).
Do not use porcelain displacers on non-vented boiler
water condensate systems over +200° F (+93° C). Stainless
steel or Karbate is recommended.
D I S P L A C E R S
S U S P E N S I O N
C A B L E
Displacers are field-adjustable at any point along the
suspension cable (10 feet (3 meters) 316 stainless steel is
standard). Monel
®
and Hastelloy
®
materials are available.
Consult the factory for longer lengths.
2
MAGNETROL [ MAGNETROL INTERNATIONAL, INC. ]
