B75-1B20-KOG Datasheet, PDF (3/8 Pages) Magnetrol International, Inc. – Non-Bleed Switch For Liquid Level Switches

1.0 Description
The Series K is a non-bleed pneumatic switch. It incorpo-
rates a three-way pneumatic valve assembly, actuated by a
magnet swing carriage. Mechanisms are available as an
option for most Magnetrol liquid level controls.
2.0 Technology
Magnetic force and the lever mechanism transmit move-
ment from the pressure vessel to the pneumatic valve.
Figure 1 shows the position of the attraction sleeve and
magnet when the liquid level is such that the attraction
sleeve is below the field of the magnet. In this position, the
flapper has been drawn away from the valve rod, permitting
the inlet air or gas to flow to a pneumatic operator. Inlet air
pressure against the ball allows the ball to seal off the
exhaust outlet.
Figure 2 shows the position of the attraction sleeve and the
magnet when the liquid level has risen, causing the attrac-
tion sleeve to attract the magnet against the enclosing tube.
In this position, the flapper actuates the air valve, closing
the supply inlet and opening the exhaust port, which
reduces the pressure in the operator to atmospheric. This
action, “close” on high, is reversible to “open” on high with
two simple adjustments (refer to page 4).
NOTE: In order to protect the switch assembly from contaminants,
filtered and dried gas/air supply is recommended.
Non-magnetic
enclosing tube
Attraction sleeve
Flapper
adjustment screw
Pivot
D
Upper
shoulder
screw
R
Reverse link
position for
opposite action
Actuating link
Air valve ^Pivot
Lower shoulder
screw
Air supply
open position
To operator
Flapper
Exhaust
closed
Magnet (swing
out position)
Falling
level
Non-magnetic
enclosing tube
R
Attraction sleeve
Flapper
adjustment screw
Air valve ^Pivot
Air supply
closed position
Pivot
D
Upper
shoulder
screw
Reverse link
position for
opposite action
Actuating link
Lower shoulder
screw
Magnet (swing
in position)
To operator
Flapper
Exhaust
open
Rising
level
Figure 1
Attraction sleeve below field of magnet
42-686 Series K Pneumatic Switch Mechanism
Figure 2
Attraction sleeve in field of magnet
1