1. SAMPLE Hydraulic SYSTEMS
KCPA
SAMPLE Hydraulic SYSTEMS
Tom Korder

2. Roméo et Juliette RAMP Two – One –, rated up to 5 GPM One – $90 / $1802
2” bore x 36” stroke, double-acting, tie rod cylinders
$90 / $180 1
Flow divider - rated to 5 GPM
$150
solenoid actuated/closed center/ industrial style valve
$120
½” x ¼” x ¼” npt medium pressure Tee
$40 4
¼” npt x 36” 4000 psi hoses
$20 / $80
½” npt “pioneer” style couplers
$18 / $36
½” x 25’ 4000 psi hoses w/ couplers
$40 / $80
TOTAL
$700
Two –
One –, rated up to 5 GPM
One –

3. Roméo et Juliette RAMP
Ramp cylinders

4. Roméo et Juliette RAMP
Ramp cylinders

5. Roméo et Juliette RAMP Hydraulics viewed from under ramp in trap room
cylinders
Flow divider

6. Roméo et Juliette RAMP

7. Roméo et Juliette RAMP

8. Roméo et Juliette SLIPSTAGE
Two –
One –, rated up to 5 GPM
One – 1
Low speed/high torque motor
$250
Stock – cable drum drive unit NC
solenoid actuated/float center/ industrial style valve
$120
sandwich style flow control valve, both A&B
$200 2
¼” npt “pioneer” style couplers
$18 / $36
¼” x 50’ 4000 psi hoses w/ couplers
$60 / $120
TOTAL
$726

9. Roméo et Juliette SLIPSTAGE

10. Roméo et Juliette SLIPSTAGE
Slipstage in “out” position

11. Roméo et Juliette SLIPSTAGE
Cable drum
Hydraulic motor

12. Shop-Built Hydraulic Trainer
AC Power Unit (500 psi, 1-2 gpm)
Tie-rod and industrial cylinders
Low speed/high torque motor
Rotary Actuator
Industrial and Mobile valves
different actuations and centers
Flow, pressure, etc. valves
sandwich and in-line style
Pressure gauges and flow meter
Hoses with couplers, adapters

13. Shop-Built Hydraulic Trainer

14. Closed Loop vs. Open Loop
pressure line
pressure line
Return line
Return line
pressure line
pressure line
Return line
inlet
exhaust

15. DESIGNING A SYSTEM Determine System Parameters
Perform System Calculations
Choose System Components

16. System Parameters What type of movement? (Linear or Rotary)
actuator type
How far does it travel?
Stroke, degree of rotation
How heavy is the object ?
total weight of all materials
What speed?
How fast of move? safe travel speed ?
How fast to get to full speed? , rpm
Other needed components?

17. B. System Calculations FORCE / TORQUE SPEED / FLOW lbs of force
in lbs of torque
SPEED / FLOW
time for stroke
time for rotation

18. AREA–PRESSURE / force
Amount of force is determined by pressure pump can deliver
measured in psi – lbs per square inch
2000 lbs of force
6000 lbs of force
1000 psi
3000 psi 2”
actuator 2”
actuator

19. calculate AREA–PRESSURE /force
F = P X A
force = pressure x area
Area = d2 x .7854
lb = psi x sq in
given a stated force needed
start with assumed area
pick a cylinder bore
start with assumed system pressure
as low as possible for safety
experiment with numbers until you find right combination
load
cylinder

20. examples AREA–PRESSURE /force
Force = Pressure x Area
Force (lb.) = pressure (lb sq in) x area (sq in)
2” bore x ?? psi system pressure
1570 lb = 500 psi x 3.14 (22x.7854) sq. in.
4710 lb = 1500 psi x 3.14 (22x.7854) sq. in.
9420 lb = 3000 psi x 3.14 (22x.7854) sq. in.

21. Multiplication of Force
F / A = P
242 x = 452 sq. in.
220 lb. / 452 sq. in. =
.48 psi
1442 x = sq. in.
.48 psi x sq. in. =
7817 lb. of force

22. FLOW / Speed rate of flow determined by pump delivery
flow determines speed of devices
measured in GPM - gallons per minute
5 seconds
10 seconds
5 gpm
2.5 gpm 2”
actuator 2”
actuator

23. calculate –FLOW / Speed
To Find Needed GPM
Flow = Area x stroke length x .26
time for stroke
gal./min. = sq. in. x in. x .26
sec.
Flow (gal./min.) = (area (sq in) x stroke length (in) x .26) / time for stroke (sec)

24. examples –FLOW / Speed Flow = Area x stroke length x .26
time for stroke
Flow (gal./min.) = (area (sq in) x stroke length (in) x .26) / time for stroke (sec)
2” bore x 36” stroke cylinder ; 30 seconds, 15 seconds, 10 seconds
.97 gpm = 3.14 (22x.7854) sq. in. x 36 in. x .26
30 sec.
1.95 gpm = 3.14 sq. in. x 36 in. x .26
15 sec.
2.93 gpm = 3.14 sq. in. x 36 in. x .26
10 sec.

25. Motor Shaft Speed Speed of the motor output shaft.
Speed =___flow x 231_____
motor displacement
shaft speed in RPM
flow in GPM
displacement in cubic inches per revolution
231 = cubic inches in a gallon

26. C. System Components Power unit (pump) Actuator (cylinder)
DCV (Directional Control Valve)
Other control devices
(pressure,flow, etc)
Power unit (pump)
Actuator (cylinder)

27. MOBILE vs. INDUSTRIAL Industrial Mobile Suggestion
closer tolerances, more expensive, valves are modular
Mobile
also known as agricultural, rugged/basic construction, more plumbing/hoses, less expensive
Suggestion
Mobile actuators, Industrial valves

28. POWER UNIT Preassembled vs. Shop assembled System Flow System Pressure
GPM – gallons per minute
System Pressure
psi – pounds per square inch
Voltage
110vac or 220vac
1 or 3 
Reservoir size
gallons

29. DCV directional control valve
Actuation method
manual, electrical, or fluid
Rating
flow and pressure
Center style
closed, open, float, or tandem
Style of construction
mobile or industrial

30. CENTER CONFIGURATIONS

31. CENTER CONFIGURATIONS
Closed or Blocked
when operating 2 or more branch circuits from one pump, where more than one must operate at one time
Float
cylinder is free to "float", piston can be pulled or pushed by an external force, sometimes used for Hydraulic motors
Open
motor" spool , minimizes circuit shock when controlling a motor, not recommended for cylinders
Tandem
popular for low power systems, provides free flow path for "pump unloading", simple/economical way to unload, holds cylinder against drift

32. Mobile (Ag) style valves

33. Industrial (Manifold) style valves

34. ACTUATOR Action Needed Amount of action needed
Linear, Rotary limited motion, Rotary continuous motion
Amount of action needed
stroke length, degree of rotation, speed
Force in both directions or only one
Force / Speed
Bore/Displacement, Pressure, GPM rating, Port sizes
Mounting Method

35. Mobile (Ag) style cylinders
Tie-Rod Cylinder
Welded Cylinders

36. Industrial (NFPA) Cylinders

37. OTHER CONTROL DEVICES Pressure Control (force) Flow Control (speed)
Additional controls
Safety Devices
Additional filtering
Electrics/Electronics
Counterbalancing
Flow dividing

38. Recommended– HIGH LEVEL $4000-$5000
Power Units 1
power unit 5-7 GPM
1000–3000 psi
3 Ø 240 AC volts
$1300
hand pump
5000 psi
$200
Valves
1 ea
tandem, closed, open centers
industrial style
manual actuation
$360
solenoid actuation
Actuators
High Torque, Low Speed Motor
$250
Tie-rod cylinder
Min psi
2” bore x 24” stroke
2” bore x 36” stroke
$70
$90
Telescoping cylinder
Equal to trap depth
$700 4
Single-acting cylinders (ram)
1” bore x 2” stroke
Accessories
stack style valves
counterbalance
flow, pressure
$500
Hoses with connectors

39. Recommended– LOW LEVEL $2000-$2500
Power Units 1
AC power unit 1-2 GPM
500–1000 psi
1 Ø 120/240
$500
hand pump
5000 psi
$200
Valves
1 ea
tandem, closed, open centers
Mobile style
manual actuation
$240
Actuators
High Torque, Low Speed Motor
$250
Tie-rod cylinder
Min psi
2” bore x 24” stroke
2.5” bore x 48” stroke
$70
$110 4
Single-acting cylinders (ram)
1” bore x 2” stroke
Accessories
inline style valves – 1 flow, 1 pressure, 1 counterbalance
Hoses

40. Recommended Systems – ADD-ONS
Combine two systems
Power Unit
Second power unit
Additional Valves
Industrial-solenoid proportional w/ electronic card
Actuators
Additional cylinders
Rotary actuator
Accessories
Flow divider
More hoses

41. SAFETY RULES
Understand the basic principle and be familiar with components of the system.
The pressure in the system should never exceed the rated pressure of the lowest rated component.
Be certain all interfaces to the fluid power system are adequate in strength.
Never work on system under pressure.
Test all circuitry with low pressure before the load is attached.
Use only the pressure required to achieve the effect.
an obstruction, overload, or added friction will stall the system until you fixed the problem
Use common sense!!!

42. Jack Miller …………………………………….
(following this slide are new slides that address these topics, these were not included in original workshop presentation)
Pump does not produce pressure.
Always use a Counterbalance valve if you have a load over the cylinder.
Be certain all interfaces to the fluid power system are adequate in strength.
…………………………………….

43. PRESSURE pressure is created whenever the flow of a fluid is resisted
load
pressure is created whenever the flow of a fluid is resisted
A. load on actuator
B. resistance or orifice in the piping
pump DOES NOT create pressure
it has the ability to push against a certain pressure A B
actuator

44. COUNTERBALANCE VALVE
counterbalance valve is an improved pilot operated check valve
the opening pressure of a pilot operated check valve depends on the pressure (applied by the load) behind the valve
the opening pressure of a counterbalance valve depends on the spring pressure behind the valve.

45. Counterbalance Valve
dynamic performance of balance valve is many times better than the performance of a pilot operated check valve
balance valve is applied as a 'brake valve' in order to get a positive control on a hydraulic cylinder or motor with a negative load
small crane systems
elevator
scissor lifts
out
pilot in
pilot

46. Counterbalance

47. Counterbalance valve
Left side of DCV is activated, cylinder will make its 'OUT-stroke‘, oil flows through integrated check valve.
To lower cylinder, the right side of DCV is activated. From that moment on pressure is built up at the rod side of the cylinder. This pressure opens the balance valve & the oil at the bottom side of the cylinder flows through the balance valve & DCV back to reservoir.
out
pilot in
pilot

48. Counterbalance valve
To lower cylinder, the right side of DCV is activated. From that moment on pressure is built up at the rod side of the cylinder. This pressure opens the balance valve
The oil at the bottom side of the cylinder flows through the balance valve & DCV back to reservoir
As the load helps lowering the cylinder, the cylinder might go down faster than the oil is applied to the rod side of the cylinder (the cylinder isn't under control at that moment).
However, the pressure at the rod side of the cylinder and therefore the pilot pressure on the balance valve will decrease and the spring moves the balance valve to the direction 'close' as long as it finds a new 'balance'. .

49. Counterbalance Circuit #1

50. “An Introduction to Hydraulics” USITT- Minneapolis 2003
Notes available at
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