These typical applications may suggest ideas for solving
your control problems:
In all systems it is essential that
adequate liquid or dry bulk material exists in a pipeline
or tank. Mercoid®, W.E. Anderson®, Proximity or
Dwyer® switches provide the control and monitor function
automatically, reliably at a moderate cost. These controls
are widely used in power generating stations, petroleum
and chemical processing, pumping stations, air conditioning,
heating, hot/cold water supply, liquid or dry bulk transfer,
water treatment, sumps and a great variety of industrial
applications. The diagrams below suggest but a few of the
many applications that protect your motors, pumps, engines
and processors.
Mercoid® displacer
type level controls, ideal controlling industrial sump pumps.
Industrial sumps and
other underground tanks are ideal applications for top mounted
Mercoid® displacer type level controls. Easily installed,
these controls use porcelain displacer type level controls.
Easily installed, these controls use porcelain displacers
that do not float on the surface of liquids but are suspended
on a coil spring and cable. As the liquid in the tank reaches
the level of the upper displacers their weight decreases
by an amount equal to the liquid displaced allowing the
spring to move the cable upward, actuation the switch and
the pump is turned on . As the liquid level falls below
the upper displacers they move only a small amount, staying
within the switch deadband until the liquid level falls
to the center of the bottom displacer. At this point the
switch Is deactivated stopping the pump. The pump will remain
deactivated until the water level rises to the upper displacers,
repeating the cycle. The displacers are not affected by
turbulence, pressure or chemicals and are excellent for
tanks with viscous or dirty liquids. The level differential
is easily adjusted by repositioning of the displacers on
the 316SS cable.
Switches control water level
and tank pressure.
A hydro-pneumatic tank
with a deep well pump maintains desired pressure in a water
system. The pump, however, delivers entrained air along
with makeup water, requiring periodic tank venting to prevent
excess pressure buildup. As both water level and tank pressure
must be maintained, one side of the W. E. Anderson®
Duotect® pressure switch is interlocked with the W.E.
Anderson® L-4 float switch via the control box. When
tank pressure falls below the preset system pressure due
to water drawdown, the Duotect® switch starts the pump
and transfers control to the float switch. When the preset
water level is reach, the float switch turns pump off. If
entrained air has increased the pressure beyond the limit
set in the other side of the Duotect® pressure switch,
after a time delay covering several normal cycles, the switch
will open the solenoid valve and vent the tank down to proper
pressure.
Proximity explosion proof Ultra-Mag™
dry level switches provide highly reliable powder and bulk
solids level monitoring capability with either the suspended
("S") or flange ("F") mounted models.
A magnetic coupling completely
seals the switch(es) in the housing from the product and
environment, assuring high reliability and enhanced safety.
Alarm capability is depicted above. Side-mounted flange
models are applicable for all bin levels. Top-of-the-bin
suspension mounted models for high and intermediate point
level provide improved sensitivity (in materials with bulk
densities as low as 5 pounds per cubic foot), and enhanced
vertical adjustment capability compared to flange mounted
models. Convenient external adjustment screws simplify field
setup. Material problems associated with flange mounted
models are solved by using suspended models. Elastomeric
diaphragms are typically used in products such as tly ash,
plastics, grain, powders, foundry sand, cement, aggregate,
coal metal chips and glass. For pneumatic )pressure_ application,
se of porous filter fabric diaphragms eliminates venting
requirements due to inherent ability to breathe. Many different
diaphragm materials are available to till the wide variety
of needs in the industrial market.
Mercoid® model 123 level
controls provide high and low alarm on large deaerator tank.
Liquid level in external
piping equals level in tank. When level rises to high limit,
float in upper model 123 is lifted, actuating switch to
sound high level alarm. When level drops to low limit, lower
model 123 sounds low level alarm.
Important Note
The control hook-ups and sketches,
and other application information shown in this Bulletin
are generalized and abbreviated to present the basic application
idea only.
We believe this application information
to be reliable, but it is intended for use by persons, at
their own discretion, having technical skill and knowledge
of the business. Neither Dwyer Instruments, Inc., nor the
Mercoid, W. E. Anderson or Proximity Divisions, shall be
liable for loss, damage, or expense directly or indirectly
arising from the use of any products described herein. In
no even shall any of these Companies be liable for direct,
indirect, special, or consequential damages.
