4
46-622 Series 3 Liquid Level Switches ASME B31.3 Construction
Swing-in
position
Return spring
Enclosing tube
(non-magnetic)
Attraction
sleeve
Magnet
HL
1.0
Introduction
Magnetrol’s Series 3 level switches are float operated units
suitable for use on clean liquid applications for level alarm,
pump control and safety shutdown functions. Units are
designed, fabricated and certified to compliance with
ASME B31.3 specifications.
1.1
Principle of Operation
The design of Magnetrol float operated level switches is
based upon the principle that a magnetic field will pene-
trate non-magnetic materials such as 316 stainless steel.
In this case, the float moves a magnetic attraction sleeve
within a non-magnetic enclosing tube and actuates a
switch mechanism. The enclosing tube provides a pressure
seal to the chamber and therefore to the process.
1.2
Operating Cycle
As the liquid level rises in the chamber (refer to
Figure 1
),
the float moves the magnetic attraction sleeve up within
the enclosing tube and into the field of the switch mecha-
nism magnet. As a result, the magnet is drawn in tightly to
the enclosing tube causing the switch to trip, “making” or
“breaking” an electrical circuit. As the liquid level falls, the
float drops and moves the attraction sleeve out of the mag-
netic field, releasing the switch at a predetermined “low
level” (refer to
Figure 2
). The tension spring ensures the
return of the switch in a snap action.
2.0
Installation
2.1
Unpacking
Unpack the instrument carefully. Inspect all units for
damage. Report any concealed damage to carrier within
24 hours. Check the contents of the packing slip and
purchase order. Check and record the serial numbers and
model numbers for future reference when ordering parts.
Serial # _____________________________________
Model # _____________________________________
Figure 1
Switch Tripped
Swing-out
position
LL
Figure 2
Switch Released