Lake Monitors Case Drain Monitor - Manual (Page 6)

Fluid Flow in Reverse Direction
The standard meter will not permit flow in the reverse direction
(opposite direction to the arrow printed on the flow rate scale). In the
reverse direction, the meter will behave in a manner similar to a leaky
check valve.
Prolonged flow in the reverse direction will cause damage to the
standard meter’s internal mechanism that could result in inaccurate
readings or premature failure of the meter. If the standard meter will
be installed in a system where reverse flow is possible, Lake recom-
mends that a check valve be installed in parallel with the meter in
order to facilitate reverse flow around the meter. Check valves are
readily available through fluid component distributors.
Alternatively, flow meters with a built-in reverse flow bypass mecha-
nism may be specified and ordered for a small additional cost. These
meters are designated by a "-RF" suffix attached to the end of the
standard 8-digit model code.
Flow meters with the built-in reverse flow bypass will allow flows in
the reverse direction of up to the maximum flow rate printed on the
flow rate scale without any damage to the monitor's internals.
If the part number label on the meter that is being installed shows a
model code containing the "-RF" suffix, then the meter may be
installed in systems where reverse flow is possible without the need
for an external check valve.
Bi-Directional Flow Measurement
In certain situations it may be necessary to measure flow rates in
both directions. For a small additional fee, an option for bi-directional
flow measurement may be specified. Meters that include this option
are designated by a "-BI" suffix attached to the end of the standard
8-digit model code.
If the part number label on the meter that is being installed shows a
model code containing the "-BI" suffix, then the meter may be
installed in any orientation regardless of flow direction.
Contact Lake Monitors for more information on reverse and bi-directional flow.
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