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Basic Hydraulic Training
Developed By Western Dynamics, LLC &
John White, President, APE
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Basic Hydraulics
Understanding some basic hydraulic
knowledge and providing examples when
working with any Hydraulic equipment is
the goal of this training program.
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Do not simply look at the pictures, but
study them, for each picture tells yousomething about hydraulics. Read the
notes with each picture carefully. At the
end of this course we will ask some
questions to see if you have increased
your understanding of hydraulics.
As You Go Through This
Course
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In The Beginning
In the 17th century Pascal developed the
law of confined fluids.Pascals Law, simply stated, says:
Pressure applied on a confined fluid is
transmitted undiminished in all directions,and acts with equal force on equal areas,
and at right angles to them.
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Pressure applied on a confined fluid is transmitted undiminished in all
directions, and acts with equal force on equal areas, and at right angles to
them.
1. The bottle is filled
with a liquid, whichis not compressible,
for example,
hydraulic oil.
2. A 10 lb. force
applied to a stopperwith a surface area
of one square inch.
3. Results in 10 lb. of
force on every
square inch
(pressure) of the
container wall.
4. If the bottom has an
area of 20 square
inches and each
square inch is
pushed on by the 10lb. of force, the
entire bottom
receives a 200 lb.
push.
5.10 lbs. x 20 sq. in.= 200
Pascals Law
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Table Of Contents
1. Introduction Hydraulics
2. Basic Symbols of Hydraulics
3. Hydraulic Fluids
4. Plumbing and Seals5. Reservoirs
6. Hydraulic contamination
7. Actuators
8. Hydraulic Pumps / Motors
9. Directional valves10. Pressure controls
11. Flow Controls
12. Accessories
13. Hydraulic Circuits
Chapters
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Chapter 1
Introduction To Hydraulics
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Pascals Law: A Closer Look
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Pascals Law Explained
Using A Fulcrum
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Explaining Piston
Displacement
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Force.
The relationship of force, pressure, and area is asfollows:
F = PA
where-
F = force, in pounds
P = pressure, in psi
A = area, in square inches
Example:
Figure 1-6 shows a pressure of 50 psi being applied to anarea of 100 square inches. The total force on the area is-
F = PA
F = 50 x 100 = 5,000 pounds
Force
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P = Solves for PressureF
A
Solving For Pressure
F = PA solves for Force. Shifting the same equation will
allow you to solve for Force or Pressure.
F = Force
P = Pressure
A = Area in sq. inches
F = PA Solves Force
P = F/A Solves Pressure
A= F/P Solves Area
piston
R
O
D
Cylinder
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How Many Cubic Inches Of Oil Is In
One Gallon?
231 cubic inches
H H d li P f W k
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How Hydraulics Performs WorkUsing A Linear Actuator
(Cylinder)
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How Hydraulics Works
To Rotate A Motor
Pump is turned by diesel engine.
Motor is turned by oil from pump.
Once oil has turned motor, it returns to the
reservoir via the return line.
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Understanding Gallons Per
Minute (GPM)
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How Flow Restriction
Effects Speed Or Distance
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How A Directional Valve
Works
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The Directional Valve Switches The
Oil DirectionRed colormeans pressure
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What A Relief Valve Does
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A Pump Doing Work
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Work Even When
Seals Leak Slightly
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Work Even When
Seals Leak Slightly
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Calculating Speed
U d di U i d
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Understanding Unrestricted
Flow And Why There Is No
Pressure Build Up
This is like our drive manifold when the vibro is not running. The oil goes through
the valve and dumps right back to the tank without building any pressure.
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Understanding Pressure And
Where It Comes From
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Reading The Relief
Valve Setting
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Oil Goes To The Path Of
Least Resistance
Ball Check
with spring
Stronger
Spring
Strongest
Spring
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Path Of Least Resistance
U d t di
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Understanding
What Your Are
Reading On ThePressure Gauge
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Understanding
Atmospheric Pressure
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Oil Has Weight
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Weight of Fluid
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Weight of Air
U i Th W i ht Of Oil T H l
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Using The Weight Of Oil To Help
Feed A Pump
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Lifting Oil
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Air Intake From Loose Connections
The drawing on the left provides some charged pressure, while the drawing on
the right requires vacuum. In either case, if there is any leaks on the suction
hose leading to the pump, the leak could draw air into the system. Air in the
system can cause pump failure due to cavitation (air in system).
Charged from oil above Vacuum required to feed pump
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When There Is No
Movement Of Oil Then ThePressure Is The Same
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How Pressure Is Lost
Through An Orifice
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Larger Orifices Steal
Less Pressure OrWork
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Flow Blocked,
Pressure Equalized!
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A Review Of Flow
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Fast Moving Oil May
Become Turbulent
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Slow Moving Oil
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Chapter 2
Basic Symbols of Hydraulics
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-continuous line - flow line
-dashed line -pilot, drain
-long chain thin Enclosure of two or more
functions contained in one unit.
Basic Symbols: Lines
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-circle - energy conversion units (pump, compressor, motor)
-circle - Measuring instruments
-semi-circle - rotary actuator
Circle, Semi-Circle
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Square, Rectangle
squares - control components
Diamond
Square, Rectangle, Diamond
diamond Condition apparatus (filter,
separator, lubricator, heat exchanger
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Spring
Restriction
Restriction
Miscellaneous
Symbols
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Pump Symbols
Fixed Displacement Hydraulic
Pump-unidirectional (pumps only whenrotated in one direction. Will not pump if turned backwards)
Variable Displacement
Hydraulic Pump-bidirectional(pumps when rotated in both forward and reverse rotation)
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Motors-FixedDisplacement
Unidirectional
(rotates only one direction)
Bidirectional (rotates in both directions)
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Reading Lines
R di S b l F
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Reading Symbols For
Pumps And Motors
Reading Symbols For
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Reading Symbols For
Cylinders
Symbols For Pilot
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Symbols For Pilot
Operated Relief Valves
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Understanding Valves
Understanding
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Understanding
Valves
Understanding
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Understanding
Reservoir Lines And
Symbols
Spool Valve Positions-
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Spoo a e os t o sFinite & Transition
in/out Stop Reverse Directions
Hand Operated(could be electric solenoid or even air operated)
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Chapter 3
Hydraulic Fluids
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APE Hydraulic Fluids
All APE units use biodegradable hydraulic
fluids, and it is friendly to the environment
when spills do occur.
Of O
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Function Of Hydraulic Oil
How Hydraulic Oil Works To
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How Hydraulic Oil Works To
Lubricate Moving Parts
How Hydraulic Oil
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How Hydraulic Oil
Effects A Spool Valve
What Happens When Water Gets
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What Happens When Water Gets
Into The Oil
C i F B d Oil
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Corrosion From Bad Oil
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Chapter 4
Hydraulic Fluid Conductors And Seals
Pi Fitti
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Pipe Fitting
Explanation Of Thread
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Explanation Of Thread
Types
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Hydraulic Hose
Components
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Hose Specifications 100R1 and
100R2
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100R3, 100R4, 100R5, 100R6
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100R9, 100R10, 100R11, 100R12
Understanding Speed Of
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g
Hydraulic Oil Through Hoses
And Why Diameter Matters
Understanding ResistanceTh h H A d Wh
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Through Hoses And Why
Diameter Is Key To Reducing
Back Pressure
The longer the hose the more
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The longer the hose, the more
resistance or friction which means
less available pressure to do work.
The longer the hose bundle, the more pressure drop you will have. This is why
we do not want to run our vibros or drills or hydraulic impact hammers with more
than 150 feet of hose. You can have so much hose that there is no available
pressure left to do the work of turning the eccentrics or drill. Vibros and drills
work better with larger hoses or shorter lengths.
Check Your Pressure With The Oil Flow
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By-Passing the Vibro.
During new production of vibros and drills, we always flush the hose bundle by putting a coupler at the end
of the hose bundle. This allows the oil to pass through the drive line hose an go back to the power unit
through the return line. We put a in-line filter on the return line to catch the dirt.
This should be done each time a new hose section on. New hoses are dirty from the work of cutting them
and installing fittings. Next time you flush the hoses please take a look at the drive pressure gauge and
read the drive pressure. You can then see how much pressure it takes just to push the oil through the
hoses.
Note also that this pressure is higher when the oil is cold. Super high back pressure could mean that you
have a restriction, like a faulty quick disconnect that is blocking the free flow of the oil. Experiences APE
employees know the approximate pressure it takes to push oil through the hoses and can see a problem
fast.
One can calculate the friction of oil going through the hoses by reading a chart and doing some math.
Power Unit with engine
at full rpm.
Pressure hose
Return
Coupler fitting to by-pass vibro for flushing oil
Vibro temporarily disconnected.
1300 psi
QDs
Drive Gauge
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Pressure Drop Through
Hydraulic Hoses.
Tubing Is Quoted In Outside
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Tubing Is Quoted In Outside
Diameter. Hydraulic Hose Is Not!
Therefore, when calculating tubing flow restrictions keep in mind
that hoses called the same size will actually be less restrictive.
H O Ri S l W k
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How O-Ring Seals Work
Th N d F B k U Ri
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The Need For Back-Up Rings
T-Seals With Back-Up Rings On
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p g
Piston
How A Seal Works On a Rotating
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g
Shaft
H Cli S l W k
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How Clip Seals Work
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How Piston Rings Work
H P ki S l W k
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How Packing Seals Work
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Chapter 5
Reservoirs
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APE Reservoirs
APE reservoirs are specially designed to
separate dirt, water and any contamination from
entering the hydraulic system.
We actually use the oil tank as a trap for filteringout this contamination.
That is why we ask you to open your oil tanks
and clean them out once a year.
Hydraulic Tank
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Hydraulic Tank
Function
How Reservoirs Work
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How Reservoirs Work
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Chapter 6
Contamination Control
Particles In Hydraulic Oil
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Particles In Hydraulic Oil
Contaminant Types And Causes
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yp
Abrasion Classes
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Particles Bigger Than Oil Film
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Trouble Shooting
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Trouble Shooting
Contaminates
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Troubleshoot Contaminates
Pump And Motor Clearances That Fail
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When Oil Is Contaminated
Wear-In Points
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Where Piston Pumps And Motors Fail When
Oil I B d
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Oil Is Bad
Contaminates From Manufacturing
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Contaminates From Manufacturing
View Of Hydraulic Reservoir
Main Sources Of
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Contamination
More Sources Of Contamination
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Filters
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Chapter 7
Hydraulic Actuators
Cylinder Actuator
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Cylinder Actuator
Telescopic Cylinder
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Telescopic Cylinder
Cylinder
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Cylinder
Cylinder With Two Equal Power
Strokes
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Strokes
Cylinder Components
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Cylinder Components
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Understanding What Pressure,
GPM, And Displacement Means
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How A Vane Motor Works
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Understanding Torque
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Chapter 8
Hydraulic Pumps / Motors
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APE Gear Pumps
The next slide shows a gear pump and how it
works. This type of pump is used on all APEpower units to provide flow to run vibros,
hammers and drills.
There are several of these pumps mounted on
the engine rear to provide the flow required forAPE units.
How A Gear Pump Works
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p
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APE Piston Pumps
APE units may use a piston pump (usually for
clamp flow) and the next slide shows how they
work.
They are different in design but still produce
flow only, the same as a gear pump shown
earlier.
How A
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How A
PistonPump
Works
APE Vibro Motor
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APE Vibro Motor
The next slide shows what a vibro
hydraulic motor looks like. It simply
takes fluid pressure and converts it to
rotational torque to turn the vibroeccentrics in the vibro.
When the eccentrics turn you get the up
and down motion required to vibrate the
pile into the ground.
How A
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Piston
MotorWorks
What Motors Turn In The APE
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APE eccentric used in vibros turned by hydraulic
motor.
Vibro
Gear Pump
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The above pump is very simple. Rotating the drive shaft causes the gears to rotate
and move oil. The faster the shaft rotates, the more oil it displaces. Output is
measured by counting the amount of oil it pumps in one revolution. Gears come in
different widths so a wider gear set will move or pump more oil per revolution.
Pump output is measured in cubic inches.
A GallonHas 231
Cubic
Inches
Gear Pump Output:
Cubic Inches X RPM
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Cubic Inches X RPM
Gear sets are sized in accordance to their cubic inch of output (displacement) per
revolution. Therefore, these gears could be size 3.6 which would mean 3.6 cubic
inches of displacement per revolution. Total output is measured by calculating total
cubic inches per minute so you would multiply 3.6 times the rotational speed per
minute to get the total output.
A Gallon
Has 231Cubic
Inches
How To Calculate Gallons Per Minute (GPM)
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If the gears In this pump are size 3.6 then it displaces 3.6 cubic inches of oil per revolution.To find total gallons per minute (GPM) just multiply the cubic inches of displacement of the
gears by the total speed the shaft turns in one minute. Example: Lets say the shaft turns
2100 rpm. The math would look like this: 3.6 X 2100 = 7,560 cubic inches.
There are 231 cubic inches in one gallon so divide 231 into 7,560 as follows:
7,560/231= 32.72 gallons per minute. (theoretical only)
A GallonHas 231
Cubic
Inches
Pump Drives Are Not Always 1:1
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When calculating the
flow of a gear pump
you must consider theratio of the pump
drive. APE pump
drives are suppose to
be 1:1 with the engine
crank shaft. Some
pump drives may turn
the pump faster (or
slower) than the
engine is turning. For
example, the J&M
(ICE) 1412 power unit
pump drive ratio was
actually a reduction.
The engine turned
faster than the
pumps.
Do not always assume that the pump drive is turning at
the same rpm as the engine. Ratios are stamped on the
pump drive.
Gear pumps Pump drive Engine
How To Calculate Gallons Per Minute (GPM)
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If the gears In this pump are 4.5 cubic inch then it pumps 4.5 cubic inches per revolution.To find total gallons per minute (GPM) just multiply the cubic inches of the gears by the
total speed the shaft turns in one minute. Example: Lets say the shaft turns 2100 rpm.
The math would look like this: 4.5 X 2100 = 9450 cubic inches.
There are 231 cubic inches in one gallon so divide 231 into 9,450 as follows:
9.450/213= 40.90 gallons per minute. (theoretical only)
A GallonHas 231
Cubic
Inches
Nature Of A Fixed Pump
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What does fixed pump mean? It means the pump displaces a fixed amount of oil per
revolution. Much like a squirt gun. Squeeze the trigger and it pumps the same amount
every time. This pump displaces the same amount every time it rotates. It pumps the
moment the shaft turns and keeps pumping until the shaft stops. The faster you turn it,
the more oil it displaces. You can slow down the output by slowing down the shaft
speed. (turning down the rpm of the engine)
Symbol
Call A Pump A Pump And
A Motor A Motor Know The
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A Motor A Motor. Know The
Difference!
Pumps get turned by engines, motors
get turned by pump displacement.
Gear Pump Gear Motor(This Turns That)
Inlet
Outlet
Squirt Gun Hydraulics(Piston Pump)Squeezing the
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(Piston Pump)
Gun Housing
Check Valve
Water
Tank or
Reservoir
Hydraulic Piston
Cylinder
q g
trigger moves the
hydraulic piston
inward which
forces thecompressed water
to squirt out the
barrel check valve.
When the trigger
is released, the
spring moves the
piston out, creatinga vacuum that
opens the tank
check valve,
sucking new water
in the cylinder for
the next shot.
Notice the checkvalves are the key
to making
hydraulics work.
Barrel Check Valve
(Pump)
This is a simple check valve type hydraulic system just like our fuel pump on the diesel
hammers; check valves that stop one direction and open in another. The injector on the diesel
is really a check valve that works just like the check valve in the barrel of this squirt gun.
Squirt Guns With larger
Pistons Can Squirt More
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Pistons Can Squirt More
Water Per Stroke
Changing piston diameter will increase volume of area. In this case, more water will be
trapped in the cylinder on the gun to the right so it will spray more water per stroke.
However, it will take more finger muscle to squeeze the one on the right, just as it takes
more horsepower to increase pump output. Gear pumps increase with gear size, piston
pumps increase with piston size or length of stroke or by adding more pistons.
1 inch 2 inch
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Chapter 9
Directional Valves
Spool Valves
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Spool Valves
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Spool Valves
Spool Valves
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Hand Operated Spool Valves
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How Hand
O t d
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Operated
SpoolValve
Works
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Detented Hand Operated Spool Valve
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SpoolTypes
Spool Types
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Solenoid Operated Spool Valves
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Pilot Operated Spool
Valves
Pilot Operated Spool Valves
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Check Valves
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Check Valves
In Line Check Valves
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e C ec a es
Spool
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p
AndCheck
Valves
Electric Symbols
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Electric Symbols
Shown On
Hydraulic
Schematics
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Electrical
Symbols
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Chapter 10
Pressure Controls
Relief
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Valves
Pressure-Control ValvesPressure-Control ValvesA pressure-control valve may limit or regulate pressure, create a particular pressure condition required for
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control, or cause actuators to operate in a specific order. All pure pressure-control valves operate in a
condition approaching hydraulic balance. Usually the balance is very simple: pressure is effective on one side
or end of a ball, poppet, or spool and is opposed by a spring. In operation, a valve takes a position wherehydraulic pressure balances a spring force. Since spring force varies with compression, distance and pressure
also can vary. Pressure-control valves are said to be infinite positioning. This means that they can take a
position anywhere between two finite flow conditions, which changes a large volume of flow to a small volume,
or pass no flow. Most pressure-control valves are classified as normally closed. This means that flow to a
valve's inlet port is blocked from an outlet port until there is enough pressure to cause an unbalanced
operation. In normally open valves, free flow occurs through the valves until they begin to operate in balance.
Flow is partially restricted or cut off. Pressure override is a characteristic of normally closed-pressure controls
when they are operating in balance. Because the force of a compression spring increases as it lowers,pressure when the valves first crack is less than when they are passing a large volume or full flow. The
difference between a full flow and cracking pressure is called override.
Relief Valves. Relief valves are the most common type of pressure-control valves. The relief valves' function
may vary, depending on a system's needs. They can provide overload protection for circuit components or limit
the force or torque exerted by a linear actuator or rotary motor. The internal design of all relief valves is
basically similar. The valves consist of two sections: a body section containing a piston that is retained on itsseat by a spring's), depending on the model, and a cover or pilot-valve section that hydraulically controls a
body piston's movement. The adjusting screw adjusts this control within the range of the valves. Valves that
provide emergency overload protection do not operate as often since other valve types are used to load and
unload a pump. However, relief valves should be cleaned regularly by reducing their pressure adjustments to
flush out any possible sludge deposits that may accumulate. Operating under reduced pressure will clean out
sludge deposits and ensure that the valves operate properly after the pressure is adjusted to its prescribed
setting.
Relief Valve Simple Type
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Relief Valve, Simple Type(1) Simple Type. Figure shows a simple-type
relief valve. This valve is installed so that oneport is connected to the pressure line or the
inlet and the other port to the reservoir. The
ball is held on its seat by thrust of the spring,
which can be changed by turning the adjusting
screw. When pressure at the valve's inlet is
insufficient to overcome spring force, the ballremains on its seat and the valve is closed,
preventing flow through it. When pressure at
the valve's inlet exceeds the adjusted spring
force, the ball is forced off its seat and the
valve is opened. Liquid flows from the pressure
line through the valve to the reservoir. This
diversion of flow prevents further pressureincrease in the pressure line. When pressure
decreases below the valve's setting, the spring
reseats the ball and the valve is again closed.
Pilot Operated Relief Valve
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Stages Of
A Relief
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A Relief
Valve As ItOpens
Compound Type Relief Valve
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Compound Type Relief Valve(2) Compound Type. Figure shows acompound-type relief valve. Passage C is
used to keep the piston in hydraulic balance
when the valve's inlet pressure is less than
its setting (diagram A). The valve setting is
determined by an adjusted thrust of spring 3
against poppet 4. When pressure at thevalve's inlet reaches the valve's setting,
pressure in passage D also rises to
overcome the thrust of spring 3. When flow
through passage C creates a sufficient
pressure drop to overcome the thrust of
spring 2, the piston is raised off its seat(diagram B). This allows flow to pass
through the discharge port to the reservoir
and prevents further rise in pressure.
Venting A Relief Valve
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Chapter 11
Flow Controls
Flow Controls
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Chapter 12
Accessories
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Chapter 13
Hydraulic Circuits
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How the Hydraulic Circuits Work
The next few slides will explain how the APE
clamp and drive hydraulic circuits and why.
The reading of hydraulic schematics is not
optional, but required to adjust or troubleshoot
any hydraulic system.
APE drive manifold circuit showing all the working
components.
Item #33 is the main directional valve spool, and item
#31 is the pilot valve that controls the main drive spool
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#31 is the pilot valve that controls the main drive spool.
We use item #32 to sense pressure in forward or reverse
lines and send a signal to item #28 the relief valve. Wecan energize item #31 to either forward or reverse and
send pump flow out the main directional control valve
item #33.
When item #31 is de-energized the vibro will cost to a
stop. All flow in returned through item #33 back to tank.
During this de-energizing we sense the line pressure in
forward or reverse depending which way we selected
item #31, and make the relief valve item #28 dump the
pump flow back to tank, which provides a smooth stop of
the pump flows. The pump flows now can go to tank
both through item #33 and item #28, which reduces
hydraulic shock. Item #30 is a needle valve and controls
how fast or slow item #28 gets the signal from item #32
shuttle valve. Sometime item #30 requires adjustment,
to reduce hydraulic shock when shifting item #33. Either
adjust it in or out just a little, you will know when it is set
correctly when item #33 can be shifted without hearingany bang or shock.
Item #28, main relief valve controls the maximum
hydraulic system pressure, which is set to 4500 psi.
APE Clamp manifold circuit shown to the
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left.
The new APE clamp manifold circuit isdesigned to run (shift) a two speed drill
whether one is used or not. The pump
flow enters at (CP) and part of the pump
flow is, about 2-gpm is sent to item #2 for
drill two speed shifting. This flow is
limited to 375-400 psi maximum by item
#7. There is no adjustment on item #1, it
is pre-set at 2-gpm. Item #7 is normally
pre-set at 375-400 psi and can beadjusted in the field if needed. Item #7
should never be adjusted above 400 psi
regardless.
The remaining pup flow (8-12 gpm) is
sent to item #4 the clamp open or close
directional control valve. Item #3 limits
the maximum clamp pressure to 4800 psi
maximum and can be adjusted in thefield.
Go to the next slide and we will continue.
Item #5 is a pilot check valve used to
trap hydraulic pressure on the closed
side of the vibro clamp. There is also
another one located right on the vibro
clamp as well. If item #4 is in the center
position, pump flow back to tank, then
it #5 ill t h d li i
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item #5 will trap any hydraulic pressure in
the clamp close line to assure clamp
remains closed.
Item #6 is an hydraulic pressure switch, it
does two things. 1.) when hydraulic
pressure in the clamp close line reaches
4500 psi (rising pressure) it will turn the
clamp close light to green. 2.) it will also
de-energize item #4 to the center
position directing pump flow back to tank.
At which time item #5 closes and trapspressure in the clamp close line.
Should the trapped pressure in the clamp
close line fall below about 4400 psi, then
the pressure switch will sense this and
turn the clamp close light off and re-
energize item #4 to direct flow back to
the clamp close line. In simple terms,
the pressure switch keeps clamp
pressure on the vibro clamp close line
between 4500 psi and 4400 psi as long
as the clamp close switch is in the clamp
close position.
Typical circuit drawing
of APE power unit
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of APE power unit
hydraulic circuit.
Should you request a
hydraulic circuit, this
is what you will get.
All your
troubleshooting is
done from this
drawings, if you
cannot read this
circuit, you need tostudy this power point
program until you
can.
Each field service
person is required to
have a book
containing all the
hydraulic circuits APE
uses in their productsbe able to read and
understand them.
Drive manifold
Electrical Solenoids
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Electrical Solenoids
Pilot valve w/spool
Shuttle valve block
Snubber
Main pilot operated
spool body w/spool
Manifold body
Relief valve
Relief valve unloader
Relief valve settingadjuster
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Solenoid
Valve
Safety
Clampmanifold
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Clamp Manifold
Clamp open gauge hose
Clamp close gauge hoseMain Clamp Relief Valve
To adjust, loosen lock not and turn
in to increase relief pressure or
turn out to decrease pressure.
Note: Normal setting is 4800 psi and must
be at least 300 psi higher than the pressure
switch or the switch will never switch to
turn the green light on.
Safety
Check
Pressure
Switch
Note: Turn slot
with screwdriver to adjust.
For driving wood piles
or other soft piles like
concrete, you may need
to lower the pressure.
Note: You cannot see
the adjusting screw inthis photo but it is
located where the arrow
is pointing. Adjust with
a straight slot screw
driver. In to increase,
out to decrease.
Pressure SwitchPressure Switches.
Pressure switches areused in various applications that require an
adjustable, pressure-actuated electrical switch
to make or break an electrical circuit at a
predetermined pressure.
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The APE clamp pressure switch is designed to
turn off the clamp solenoid that is pushing thevalve to send oil to the clamp. Once the clamp
is closed the valve does not need to send any
more oil to the clamp so the pressure switch
cuts the power to the solenoid so the valve can
go to center. At the exact same time, the
same switch tells the green light to come on at
the pendant. The green light stays on if the
pressure does not drop below the pressure
switch setting. If the pressure does drop, the
switch will turn on the solenoid, sending more
oil to the clamp and during this process, the
green light will be turned off. The switch also
serves as a safety warning device to tell theuser that something is leaking or wrong.
A flashing green light on the pendant means
the switch is going on and off due to leakage
from a hose, seal, or quick disconnect.
Clamp Manifold
Note:
Set all valves with
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p
Clamp relief valvePressure switch
Adjusting screw
for setting clamp
pressure.
Solenoid Valve
SO Cord
Clamp manifold (other than bulkhead mounted)
no disconnects
connected.
When setting
clamp pressure,
this pressure
switch must be set
300 psi below the
relief valve. Youmust first set the
main relief valve
to 4800 psi and
then set the
pressure switch.
4800 psi
4500 psi
Set this valve
by reading
Clamp Open
gauge.
A Few Review Questions To Answer
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We have a few review questions to answer after studying this course. An Excel
spreadsheet of the questions can be downloaded from the web page site and
you can enter your answers to the questions.
You then can Email this spreadsheet with your name, location and return Email
address to [email protected], we will review your answers and send
back to you the results via Email.
This is not optional, it is required. We will maintain in your personnel file
completion of this program. You may send in your test answers as many times
as you wish, this will not count against you. APE will have more programs in
the near future for you to review, and from time to time a question review will be
t t f l ti
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