Liquid Controls Mechanical Eliminators - Manual (Page 5)

5
Principles of design
Liquid Controls mechanical air and vapor eliminators
remove air and vapor from metering systems. Removing
the air and vapor from a metering system increases the
accuracy of the meter by allowing only liquid to pass
through the meter for measurement.
At installation, LC mechanical air and vapor eliminators
are piped to a storage tank to provide a pathway and a
receptacle where the evacuated air and vapor can be
deposited. After the air (or vapor) has left the metering
system, mechanical air and vapor eliminators seal off the
pathway to prevent liquid from entering the storage tank.
InTrodUCTIon
orIenTaTIon and CoMPonenTs
Liquid Controls mechanical air and vapor eliminators are
typically bolted, in an upright position, onto the top of a
strainer on the inlet side of the meter. Before operation,
air and vapor eliminators must be piped to a storage
tank and, on most meter systems, to an air check (or
differential) valve. Installation and maintenance must be
done by a qualified technician. See page 16 for Field
Piping installation.
Vent Ports Open
Vent Ports Sealed
aIr and vaPor elIMInaTIon
Liquid Controls mechanical air and vapor eliminators
eliminate air (or vapor) instantly and continuously as
it enters the meter system. Because air and vapor are
lighter and less dense than liquid, they are naturally
pushed up above the product flow. Air and vapor
eliminators are set above the product flow so that air in
the system is pushed up into the the cavity inside the
air eliminator housing, out the valve plate vent ports,
through the piping, and into a storage tank (see middle
left figure). As air is evacuated from the system, the
liquid level inside the air eliminator cavity is allowed
to rise and push the float up. As the float moves up, it
presses the reed strips against the valve plate sealing
the vent ports and preventing product from passing
through the piping and into the strorage tank. If more
air enters the system, it will rise to the top of the air
eliminator cavity. The air will accumulate there and push
the liquid level, and the float, lower. As the float falls, the
reed strips pull away from the vent ports, and air can be
vented before it enters the system.
In this manual, the term “ storage tank,” refers to any type of
receptacle meant to hold air or vapor expelled from the meter
system by an air eliminator. And because mechanical air and
vapor eliminators remove both air and vapor, depending on the
application, the terms “ air” and “vapor” are interchangeable
throughout this manual.
“storage tank”