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Hydraulics For The Long Term
• Most Companies Make Very Few Preventive
Maintenance Checks Such As:
Oil Level
Filter Condition
Leaks
Pump And Motor Coupling
Forklift Maintenance Checklist
How To
Improve The Longevity Of Your
Hydraulic System
•
Testing of the pump(s) to determine if the proper
volume is being delivered to the system. By making
this test regularly the pump can be replaced on a
down day and not when it fails and interrupts
production.
•
Checking the accumulators to make sure they are
properly pre-charged which is necessary to achieve
the desired speed to maintain production.
How To Improve The Longevity Of Your
Hydraulic System
•
On any given hydraulic system, there should be
some lines that are hot (above 130 degrees), warm
(100-130 degrees), and cool or at ambient
temperature. By checking the temperature of these
lines on a regular basis a component failure can be
found before the system fails completely.
•
One of the main issues in a hydraulic system is
leakage. One drop of oil that drips once per second
will lose 405 gallons a year. If leakage is occurring
there is a reason for it.
How To
Improve The Longevity Of Your
Hydraulic System
•
•
One of the biggest problems in systems today is
that the pressures are out of adjustment which
causes excessive force, heat, leakage and wasted
electrical energy. You will identify any pressure
setting issues and many times correct them during
the checks.
Check to verify that the pipe and tubing clamps are
properly spaced and are of the proper type.
Make sure that the hoses are properly installed to
prevent pre-mature failure and oil loss.
How To
Improve The Longevity Of Your
Hydraulic System
•
Check the condition of the filters if a visual or
electrical indicator is available.
•
Verify that the air and water heat exchangers are
operating properly to reduce the oil temperature to
an acceptable level. If the oil temperature is above
140 degrees then oil will start breaking down
causing sludge and varnish in the system.
How To
Improve The Longevity Of Your
Hydraulic System
•
Check the condition of the breather cap on the
reservoir.
•
Sound checks to determine pump cavitation,
aeration or valves bypassing in the system.
Hydraulic Reliability Checks
That Should Be Made On A Regular Scheduled Basis
1. Record the maximum and minimum
pressures in the system.
Max
PSI
Min
PSI
Hydraulic Reliability Checks
2. Record the oil temperature in the reservoir.
If there is no thermometer or unreadable,
use a temperature gun.
°F
Hydraulic Reliability Checks
3. Check the relief valve tank line for heat. The
tank line should be considerably cooler than
the inlet line.
°F
Compensator Set Higher Than The Relief Valve
Adjusting The Pressures
Setting a Compensator In a System With a Relief Valve
Adjusting The Pressures
Setting a Compensator In a System With a Relief Valve
Adjusting The Pressures
Setting a Compensator In a System With a Relief Valve
Adjusting The Pressures
Setting a Compensator In a System With a Relief Valve
Adjusting The Pressures
Setting a Compensator In a System With a Relief Valve
Adjusting The Pressures
Setting a Compensator In a System With a Relief Valve
Hydraulic Reliability Checks
4. Check the temperature of the pump suction
line and case drain line.
Suction Line
°F Case Drain Line
°F
Pressure Compensating Piston Pump
Case Drain Line
Suction Line
Checking The Pumps Case Drain Flow
There are two methods of checking case
drain flow:
• Run the case drain flow into a container of
known size and time it
Checking The Pumps Case Drain Flow
• A flow meter may be permanently
installed in the case drain line.
Hydraulic Reliability Checks
5. Check the temperature of the accumulator
shell for heat.
Top Of Shell
°F Bottom Of Shell
°F
Checking The Accumulator
Checking the pre-charge with a charging rig.
Bleed Valve
Gas Chuck
Hose Connection
Hydraulic Reliability Checks
6. When was the last date the return filter was
changed? Check the visual indicator for the
filter condition.
Hydraulic Reliability Checks
7. Check the condition of the breather caps.
When was the last time they were changed?
Hydraulic Reliability Checks
8. Check the oil level in the reservoir. A sight
glass is usually mounted on the side of the
tank.
Hydraulic Reliability Checks
9. Check the condition of the heat exchanger.
Are the fins clean and is there good air flow?
Hydraulic Reliability Checks
10. Check the condition of the hydraulic hoses.
Are any rubbing or over 4-6 feet in length? If
so, hose protectors should be placed over
the rub points.
Hydraulic Reliability Checks
11. Check the condition of the pipe clamps and
make sure the proper clamps are used.
Clamps should be spaced every 5 – 8 feet
and within 6” of where the pipe terminates.
Improper Clamping
Proper Clamp
Hydraulic Reliability
•
•
•
These are just 11 checks that should be
made on a regular scheduled basis.
Depending on the hydraulic system, there
can be as many as 25 reliability checks.
A Hydraulic System Reliability Checklist
should be developed for all your hydraulic
systems.
Questions
Hydraulic IQ Test
How Much Do You Really Know About Hydraulics?
1. Force = _____ x _______
Hydraulic IQ Test
2. Pascal’s Law states
that pressure in a
confined body of fluid
will act _______ in all
directions.
Hydraulic IQ Test
3. Power is the ____ at which
work is done.
Hydraulic IQ Test
4. Pressure in a hydraulic system
is caused by a __________ to
flow
Hydraulic IQ Test
5. There are six reasons why a valve
solenoid can fail. Can you name
one?
Hydraulic IQ Test
6. When a solenoid is checked with an
ohmmeter and the reading is less
than 50 ohms, what does this mean?
Hydraulic IQ Test
7. What five characteristics does
the valve symbol below have?
Hydraulic IQ Test
8. Which valve center position
would be best to use with a
fixed displacement pump?
Hydraulic IQ Test
9. If you were replacing the pilot
valve on a solenoid controlled
hydraulic piloted valve, which
center position would be correct?
Hydraulic IQ Test
10. Which valve is larger?
Hydraulic IQ Test
11. What two checks would you
make to be sure an
accumulator used for volume is
operating properly?
Hydraulic IQ Test
12. If no heat is felt on a
bladder accumulator, one of two
things has happened. They are:
Hydraulic IQ Test
13. The relief valve serves two
functions in a hydraulic
system with a variable
displacement pump.
They are:
Hydraulic IQ Test
14. What is usually the number 1
reason why pumps cavitate?
Hydraulic IQ Test
15. True or False: A particle of
contamination whose size is the
diameter of a human hair is not
harmful to a hydraulic system.
Hydraulic IQ Test
16. What happens to the electric
motor current draw when a pump
compensates?
Thank You For Attending!
Copyright, 2012 © GPM Hydraulic Consulting, Inc.
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