MACHINERY LUBRICATION- INDIA MARCH-APRIL 2020 | Page 21

MLI
Pressure Compensating
The pressure-compensating flow control
(Figure 5) is designed to maintain a
constant flow regardless of the pressure
drop across it. This control is used in
systems where the load weight changes,
but it is important to maintain a constant
speed. Without the p
​ ressure-​compensating
feature, a heavier load will move more
slowly than a lighter load. The pressure-
compensating flow control is available as
either a fixed- or variable-orifice type.
Temperature
Compensating
If the ambient temperature varies enough
to affect production, the answer may
be a temperature-compensating f low
control. The additional symbol looks a
bit like a thermometer. This control can
be expensive, so it is unlikely to be found
unless it is truly needed. The temperature-
compensating flow control will maintain a
constant flow regardless of any changes in
oil viscosity. It is available as either a fixed-
or variable-orifice type, and can also be a
pressure-compensating control if the load
weight changes constantly.
control specified by the designer failed to
take certain conditions into account, or
that a flow control has been replaced with
one of the wrong types. If speed control
is important to your operation, switching
to one of these flow controls may help. ML
About the Author
Jack Weeks is a hydraulic instructor and
consultant for GPM Hydraulic Consulting.
Since 1997 he has trained thousands of
electricians and mechanics in hydraulic
When I am called to help diagnose
problems in a system and the issue concerns
a flow control, the most common problem I
find is that an incorrect type of flow control
has been installed. It may be that the flow
troubleshooting methods. Jack has also taught
radio-wave propagation for the U.S. Air Force
and telecommunications equipment operation
and repair for the Central Intelligence Agency
at American embassies overseas.
www.machinerylubricationindia.com
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