Liquid Controls M-MA Meters - Manual (Page 6)

Liquid Controls meters are positive displacement
meters. They are designed for liquid measurement in
both custody transfer and process control applications.
They can be installed in pump or gravity flow systems.
Because of their simple design, they are easy to
maintain, and easy to adapt to a variety of systems.
The meter housing (1) is designed with three cylindrical
bores (2). Three rotors, the blocking rotor (3) and
two displacement rotors (4, 5), turn in synchronized
relationship within the bores. The three rotors are
supported by bearing plates (6, 7). The ends of the
rotors protrude through the bearing plates. The blocking
rotor gear (8) is placed on the end of the blocking
rotor. The displacement rotor gears (9, 10) are placed
on the ends of the displacement rotors. These gears
create the synchronized timed relationship between the
three rotors.
As fluid moves through the meter housing, the rotor
assembly turns. The liquid is broken into uniform
sections by the turning rotors. Fluid displacement occurs
simultaneously. As fluid enters, another portion of the
fluid is being partitioned and measured. At the same
time, the fluid ahead of it is displaced out of the meter
and into the discharge line. Since the volume of the
bores is known, and the same amount of fluid passes
through the meter during each revolution of the blocking
rotor, the exact volume of liquid that has passed through
the meter can be determined with a high degree of
accuracy.
This true rotary motion is transmitted through the
packing gland, the face gear, the adjuster drive shaft,
and the adjuster to the register stack and counter. True
rotary motion output means consistent accuracy since
the register indication is in precise agreement with the
actual volume throughput at any given instant.
At any position in the cycle, the meter body, the blocking
rotor, and at least one of the displacement rotors form
a continuous capillary seal between the unmetered
upstream product and the metered downstream product.
Because the product is separated by the capillary seal,
hoW lc Meters Work
no metal-to-metal contact is required within the metering
element. This means no wear. No wear means no
increase in slippage, and no increase in slippage means
no deterioration in accuracy.
Throughout the metering element, the mating surfaces
are either flat surfaces or cylindrical faces and sections
that are accurately machined. These relatively simple
machining operations, plus the fact that there is no
oscillating or reciprocating motion within the device,
permits extremely close and consistent tolerances within
the LC meter.
The product flowing through the meter exerts a
dynamic force that is at right angles to the faces of the
displacement rotors. The meter is designed so that the
rotor shafts are always in a horizontal plane. These two
facts result in no axial thrust; therefore, LC meters do
not need thrust washers or thrust bearings, the rotors
automatically seek the center of the stream between the
two bearing plates, eliminating wear between the ends of
the rotors and the bearing plates. Once again, no wear
results in no metal fatigue and no friction.
Liquid Controls meters are made of a variety of materials
to suit a variety of products. Because of their no-wear
design, capillary seals, and unique rotary metering, LC
meters provide unequalled accuracy, long operating life,
and unusual dependability.
Meter Element Exploded Line Drawing
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