three basic types of level switches to meet the various requirements
for alarm and control action for liquid level gauges. These switches
mount on the chamber of a level gauge. All are non-invasive switches
that are magnetically activated by the level gauge float directly
through the chamber wall of the gauge. These switches are easily adjustable.
There is no piping to redo for a simple change in set point.
All of these switches may all be wired for rising or falling level
and/or NC or NO operation. Each switch has approximately 1/2 inch
deadband to eliminate chattering and all have "break before make"
MLS-3 / MLS-3EX Reed Switch
The MLS-3 is a hermetically sealed
reed switch with form C contacts. A bias magnet latches the switch,
maintaining the contact after the float continues to rise or fall
with the liquid level. The MLS-3EX is an explosion-proof version
of the MLS-3 with terminal block.
The MLS-9EX is an explosion-proof,
hermetically sealed mercury tilt switch. This switch has a 10A contact
current rating and is capable of operating valves and activating
pump starters without an interposing relay. It is a SPDT switch
with "break before make" action. As the float passes, the switch
changes state with a rocking action caused by a rod magnet which
latches it in place. The contacts are maintained until the float
passes again in the opposite direction.
The PS-1 is a pneumatic
relay that switches air pressures from 30 to 100 psi. It is basically
a flapper-nozzle type assembly that operates a pneumatic relay.
As the float passes, the flapper either clears or blocks the nozzle
opening creating a vent or a pressure action. This action moves
the relay diaphragm and switches the supply air pressure to the
output. When the float passes again in the opposite direction, the
pressure is removed and the output is vented. The PS-1 is best suited
for sounding pneumatic alarms, activating winkies or opening and
closing air or gas activated valves. It is ideal for use for level
control where no power is available.