MACHINERY LUBRICATION- INDIA SEPTEMBER-OCTOBER 2019 | Page 21

Al Smiley | GPM Hydraulic Consulting
HYDRAULICS
Simple Tests to Increase
Reliability
of Your
Hydraulic
Systems
the
Often the only tests and
actions performed on a
hydraulic
system
involve
changing the filters, sampling the oil
and checking the oil level. As long as the
system is operating, the mentality of “if
it ain’t broke don’t fix it” frequently
prevails. However, on any given system
in your plant, you should perform 15 to
20 regular reliability tests while the
system is operating. There are also
several checks and procedures that
should be completed during shutdowns
or down days. The following preventive
maintenance and reliability tests can
help improve the efficiency and
operation of your hydraulic systems and
machines.
Check the Oil Reservoir
A good time to check the oil reservoir is
when your plant or system is down.
Maintenance mechanics and electricians
usually chuckle when I tell them that the
reservoir should be cleaned at least once
a year. One mechanic at a large wood
products plant told me that the reservoir
on one system hadn’t been cleaned since
the mill started up 17 years ago.
Other than oil storage, the two main
purposes of the reservoir are to dissipate
An example of an oil reservoir in a hydraulic system
1 = Heater thermostat
3 = Switch settings

5 = High-temperature switch

2 = Suction strainer
4 = Breather cap
6 = Heat exchanger
heat and to allow contaminants to
settle. If the reservoir is not cleaned, not
only will its ability to dissipate heat be
diminished, but it will act as a heat sink.
Temperatures can easily soar well above
the maximum recommended level of
140 degrees F. Oil will then start
breaking down, leading to sludge and
varnish in the system. If the contaminants
are not removed from the reservoir, they
will be drawn into the pump, causing
premature failure
components.
of
the
system
Many reservoirs contain a suction
strainer to keep large particles from
entering the pump. Most suction
strainers have a 74-micron rating,
whereas the tolerances inside pumps
and valves are typically 3 to 8 microns.
Always use a lint-free cloth when
cleaning a reservoir. If a solvent is
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