hydraulic system design

1. HYDRAULICS SYSTTEM DESIGN

2. DESIGN CONSIDERATIONS

3. INFORMATION REQUIRED FOR DESIGN

8. 1000

14. A machine slide is moved by means of hydraulic cylinder . The motion of the cylinder is as
follows,
a) Initially it moves through a distance of 250 mm against load at 15000 N in about 5
seconds.
b) It followed by working stroke of 100 mm against an effective load of 35000 N . The feed
rate during this part of stroke is required to be between 0.5 to 1 m/min.
c) The return stroke is to be as fast as possible.
A meter-out circuit to be used. Draw a circuit which will fulfils these requirements.
Select different components you have used in the circuit from given data .
Soln :- 1. Meter out circuit for fast approach slow working
Given:- X1 = 250 mm = 0.25 m , X2 = 100 mm = 0.1 m , Fext1 = 15000 N ,
Fext2 = 35000 N, t1 = 5 seconds, Vext1 = Distance during this part/
Time taken = 0.25/ 5 = Vext1 = 0.05 m/s ,
Vext2 = 0.5 to 1 m/min

15. Step-I : CIRCUIT DIGRAM

16. Step-II : DESIGN STAGE
(A) CALCULATION FOR FORWARD STROKE: Vext1 = 0.05 m/s , Vext2 = 0.5 to 1 m/min
For safer side taking higher feed rate which is 1 m/min.
Vext1 = 0.05 m/s
Vext2 = 1 m/min = 0.0167 m/s
SELECTION : Selecting model A5 Cylinder for Getting Highest Safety…
From data given : DP = 100mm
Dr = 50mm

17. Now, calculating pressure and flow rate both part of forward stroke,
a) For first part of stroke :
Pext1 = Fext1/ AP = 15000/ (π/4)*(01)2
Pext1 = 19.10 *105 N/m2
Pext1 =19.10 bar
Flow rate for this part
Qext1 = AP*V ext1 = (π/4)*(0.1)2* 0.05
Qext1 = 3.93 * 10-4m3/s
Qext1= 23.56 lpm
P=F/A

18. b) For second part of stroke :
Pext2 = Fext2/ AP = 35000/ (π/4)*(01)2
Pext2 = 44.56 *105 N/m2
Pext2 = 44.56 bar
Flow rate for this part
Qext2 = AP*V ext2 = (π/4)*(0.1)2* 0.0167
Qext2 = 1.312 * 10-4 m3/s
Qext2= 7.87 lpm
B) CALCULATION FOR RETURN STROKE:
Qret = 3.93 * 10-4m3/s
Qret= 23.56 lpm
For return stroke effective area for pressure will be (AP-AR)
Qret= (AP-AR)*Vret
3.93 * 10-4= π/4 *(0.12 -0.052) *V ret
V ret = 0.0667 m/s
Note:-In order to calculate return speed (which is as fast as possible), the
maximum flow rate from forward stroke is considered

19. From this we can calculate the time required for the return stroke to cover 350
mm (250+100) distance.
V ret = Stroke/ Time
Time = 0.35/0.0667
Time = 5.24 sec.
Now from system parameters
Maximum working pressure= 44.56 bar
Maximum flow rate= 23.56 lpm

20. Step-III : SELECTION OF COMPONENTS
1) OIL RESERVOIR: MODEL:T2
Reservoir capacity should be 3 to 4 times The maximum flow rate
CAPACITY = 3* 23.6 = 70.68 Liters
2) STRAINER:S1
3) PUMP: P4 So discharge required is 23.56 lpm at 19.09bar
and 7.854 at 44.56 bar.
Maximum discharge of this pump is 25.1 lpm at 0 bar.
4) DCV: D2
Maximum
working
pressure=
44.56 bar
Maximum flow
rate= 23.56
lpm

21. Step-III : SELECTION OF COMPONENTS
5) PRV : R3
6) FCV: F4
7) PG: 3
8) Check Valve: C2
Maximum working pressure=
44.56 bar
Maximum flow rate=
23.56 lpm

22. SELECTION OF COMPONENTS
SELECTION OF COMPONENTS

25. EXAMPLE:
A 50 KN hydraulic press has stroke of 1m. The main is
required to move down with velocity of about 5m/min for
the first 80cm against a ram negligible load. The ram is
slowed down to a velocity of 2m/min for the next 12 cm
against load of 12KN, followed by the working stroke of last
8 cm developing a maximum force of 50KN. The cylinder is
returned as quickly as possible and is to be held at the top
most position.
Draw a circuit which will fulfill these requirements. Select
the different components used in the circuit from the data
tables. Mention the rating of components in case it is not
available in the given data.

26. Step-I : CIRCUIT DIGRAM

27. Step-II : DESIGN STAGE

28. Step-I : CIRCUIT DIGRAM

29. Step-III : SELECTION OF COMPONENTS

30. Step-III : SELECTION OF COMPONENTS

31. Step-III : SELECTION OF COMPONENTS
(g) Flow control valve (7):
Minimum flow capacity = 15.7 lpm
Working pressure = 63.66 bar
Select model F3 with maximum operating pressure 105 bar and flow range 0- 16.3 lpm
(h) Pressure gauge (8) :
Select model PG3= 0-100 bar

32. DATA
Model Flow Capacity
(LPM)
Model Range
(bar)
S1 38 PG1 0-25
S2 76 PG2 0-40
S3 152 PG3 0-100
S4 180 PG4 0-160
Model
Delivery in LPM
At 0 bar At 35 bar At 70 bar
P1 8.5 7.1 5.3
P2 12.9 11.4 9.5
P3 17.6 16.1 14.3
P4 25.1 23.8 22.4
P5 39.0 37.5 35.6
Model Max. Working
Pressure (Bar)
Flow Range
(LPM)
C1 210 15.2
C2 210 30.4
C3 210 76
1.Suction Strainer 2. Pressure Gauge 3. Vane Pump 10. Oil Reservoir
7. Check Valve 4. Relief Valve 5. Flow Control Valve
Model Flow Capacity (LPM) Max. Working Pressure
(bar)
R1 11.4 70
R2 19 210
R3 30.4 70
R4 57 105
Model Working Pressure
(bar)
Flow Range (LPM)
F1 70 0-4.1
F2 105 0-4.9
F3 105 0-16.3
F4 70 0-24.6
Model Max. Working
Pressure (bar)
Flow Capacity (LPM)
D1 350 19
D2 210 38
D3 210 105
6. Direction Control Valve 8. Pilot Operated Check Valve 9.Actuators/Cylinder
Model Max. Working
Pressure (Bar)
Flow Capacity
(LPM)
PO1 210 19
PO2 210 38
PO3 210 76
Model Bore diameters
(mm)
Rod diameters (mm)
A1 25 12.5
A2 40 16
A3 50 35
A4 75 45
A5 100 60
Model Capacity (liters)
T1 40
T2 100
T3 250
T4 400
T5 600

33. EXAMPLE:
Two identical cylinders A and B are to be operated
simultaneously. The cylinder A moves against a load of 25KN
while cylinder B has a load of 20KN. Both cylinders have a
stroke of 1m. The working stroke is to be completed about
20 seconds time. The return stroke of the cylinder B is start
only after the cylinder A Is completely retracted. The return
speeds are to be as fast as possible.
Draw a circuit which will fulfill these requirements. Select
the different components you have used in the circuit from
the data given. Mention rating components in case it is not
available in the given data.

34. Soln :- SEQUENCING CIRCUIT (A-B-A-B)
Given:- XA&B = 1m FextA = 25 KN ,
FextB = 20 KN, TA&B = 20 seconds,

35. Step-I : CIRCUIT DIGRAM
A-B-A-B
OPERATING CONDITIONS

36. Step-II : DESIGN STAGE
Model Bore diameters
(mm)
Rod diameters
(mm)
A1 25 12.5
A2 40 16
A3 50 35
A4 75 45
A5 100 60
Above capacity pump not available in given data
Actuators/Cylinder

37. Step-II : DESIGN STAGE
The pressure in the power cylinder does not as a rule exceed approximately 70
bar and also the ratio of cylinder length “L” to the diameter “D” over 20 is not
available .
So for cylinder A and B model A5 with bore dia. = 100mm
and rod dia. = 50mm is selected. Model Bore diameters
(mm)
Rod diameters
(mm)
A1 25 12.5
A2 40 16
A3 50 35
A4 75 45
A5 100 60

38. Step-II : DESIGN STAGE
Flow required (Q) :
Now from system parameters
Maximum working pressure= 31.83 bar
Maximum flow rate= 47.1 lpm

39. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 31.83 bar
Maximum flow rate= 47.1 lpm
Model
Delivery in LPM
At 0
bar
At 35
bar
At 70
bar
P1 8.5 7.1 5.3
P2 12.9 11.4 9.5
P3 17.6 16.1 14.3
P4 25.1 23.8 22.4
P5 39.0 37.5 35.6 P5
Model Capacity
(liters)
T1 40
T2 100
T3 250
T4 400
T5 600
T3
Vane Pump Oil Reservoir

40. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 31.83 bar
Maximum flow rate= 47.1 lpm
D3
DCV
Model Max.
Working
Pressure
(bar)
Flow
Capacity
(LPM)
D1 350 19
D2 210 38
D3 210 105
S2

41. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 31.83 bar
Maximum flow rate= 47.1 lpm
R4
Relief Valve
C2
Model Max.
Working
Pressure
(Bar)
Flow
Range
(LPM)
C1 210 15.2
C2 210 30.4
C3 210 76
Check valve
Mode
l
Flow
Capacity
(LPM)
Max.
Working
Pressure
(bar)
R1 11.4 70
R2 19 210
R3 30.4 70
R4 57 105

42. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 31.83 bar
Maximum flow rate= 47.1 lpm
Sequence Valve: Since it is used in the circuit, its
capacity may be more than 23.5 lpm
47.1/2 = 23.51 lpm

43. Step-I : CIRCUIT DIGRAM
A-B-A-B
OPERATING CONDITIONS

44. EXAMPLE:
A machine tool cross slide is moved by means of hydraulic system. The
motion of the cylinder is as follows:
a) Initially it moves through a distance of 150 mm against a load of 15KN in
about 4 seconds.
b)It followed by working stroke of another 150 mm against an effective load
of 25 KN. The feed rate during this part of stroke is required to be 1m/min.
c) The load during return stroke is 15KN. Calculate velocity and time required
to complete the return stroke.
A meter out type of circuit is used. Draw a circuit which will fulfill these
requirements. Select the different components you have used in the circuit
from the data given. Mention rating components in case it is not available in
the given data.

45. Step-I : CIRCUIT DIGRAM

46. Step-II : DESIGN STAGE
Model Bore diameters
(mm)
Rod diameters
(mm)
A1 25 12.5
A2 40 16
A3 50 35
A4 75 45
A5 100 60
Actuators/Cylinder

47. Step-II : DESIGN STAGE

48. Step-II : DESIGN STAGE

49. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 56.59 bar
Maximum flow rate= 9.94 lpm
Model
Delivery in LPM
At 0
bar
At 35
bar
At 70
bar
P1 8.5 7.1 5.3
P2 12.9 11.4 9.5
P3 17.6 16.1 14.3
P4 25.1 23.8 22.4
P5 39.0 37.5 35.6 P3
Model Capacity
(liters)
T1 40
T2 100
T3 250
T4 400
T5 600
T1
Vane Pump Oil Reservoir

50. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 56.59 bar
Maximum flow rate= 9.94 lpm
D1
DCV
Model Max.
Working
Pressure
(bar)
Flow
Capacity
(LPM)
D1 350 19
D2 210 38
D3 210 105
S1

51. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 56.59 bar
Maximum flow rate= 9.94 lpm
Relief Valve
C1
Model Max.
Working
Pressure
(Bar)
Flow
Range
(LPM)
C1 210 15.2
C2 210 30.4
C3 210 76
Check valve
Mode
l
Flow
Capacity
(LPM)
Max.
Working
Pressure
(bar)
R1 11.4 70
R2 19 210
R3 30.4 70
R4 57 105
R1

52. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 56.59 bar
Maximum flow rate= 9.94 lpm
F3

53. EXAMPLE:
Draw a simple hydraulic circuit which will operate a hydraulic
cylinder of a machine. The load during the forward stroke is
15 KN and that during the return stroke is approximately 9.5
KN. The forward and return speeds are about 3.5 m/min and
5.5 m/min respectively. The total stroke of the cylinder
300mm. A provision is required to hold the cylinder
anywhere in between the end positions. Draw a circuit which
will fulfill these requirements. Select the different
components you have used in the circuit from the data given.
Mention rating components in case it is not available in the
given data.

54. Step-I : CIRCUIT DIGRAM

55. Step-II : DESIGN STAGE

56. Step-II : DESIGN STAGE
Effective area at road side

57. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 19.098 bar
Maximum flow rate= 32.39 lpm
Model
Delivery in LPM
At 0
bar
At 35
bar
At 70
bar
P1 8.5 7.1 5.3
P2 12.9 11.4 9.5
P3 17.6 16.1 14.3
P4 25.1 23.8 22.4
P5 39.0 37.5 35.6 P5
Model Capacity
(liters)
T1 40
T2 100
T3 250
T4 400
T5 600
T2
Vane Pump Oil Reservoir

58. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 19.098 bar
Maximum flow rate= 32.39 lpm
D2
DCV
Model Max.
Working
Pressure
(bar)
Flow
Capacity
(LPM)
D1 350 19
D2 210 38
D3 210 105
S1

59. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 19.098 bar
Maximum flow rate= 32.39 lpm
Relief Valve
C3
Model Max.
Working
Pressure
(Bar)
Flow
Range
(LPM)
C1 210 15.2
C2 210 30.4
C3 210 76
Check valve
Mode
l
Flow
Capacity
(LPM)
Max.
Working
Pressure
(bar)
R1 11.4 70
R2 19 210
R3 30.4 70
R4 57 105 R4

60. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 19.098 bar
Maximum flow rate= 32.39 lpm
D2
DCV
Model Max.
Working
Pressure
(bar)
Flow
Capacity
(LPM)
D1 350 19
D2 210 38
D3 210 105
A5
Model Bore
diameters
(mm)
Rod
diameters
(mm)
A1 25 12.5
A2 40 16
A3 50 35
A4 75 45
A5 100 50

61. EXAMPLE:
A machine slide is moved by a cylinder. The motion required is as
follows.
a) Initially the cylinder moves against load of 2.5 KN till it
reaches the work piece at a speed of about 1.5 m/min.
b) The speed drop down to about 0.5m/min as soon as the
load increases to 12.5KN.
c) The return motion is against load of 2.5KN.
A meter out type of circuit is used. Draw a circuit which will fulfill
these requirements. Select the different components you
have used in the circuit from the data given. Mention rating
components in case it is not available in the given data.

62. Step-I : CIRCUIT DIGRAM

63. Step-II : DESIGN STAGE

64. Step-II : DESIGN STAGE

65. Step-II : DESIGN STAGE

66. EXAMPLE:
A hydraulic cylinder used to operate a machine has the following
requirements:
a) Initially it moves through a distance of 300 mm against a load of 30 KN in
about 6 seconds.
b)It followed by working stroke of another 100 mm against an effective load
of 50 KN. Which should be completed in 3 to 6 seconds. The time required
is to be adjustable.
c) The return motion of 400mm is against a load of 40 KN which should be
completed in about 7 seconds time.
Facility is required to hold the cylinder anywhere in between the entire
stroke. Solenoid operated valves are used in the circuit. A meter out type of
circuit is used.
Draw a circuit which will fulfill these requirements. Select the different
components you have used in the circuit from the data given. Mention rating
components in case it is not available in the given data.

67. Step-I : CIRCUIT DIGRAM

68. : DESIGN STAGE

69. : DESIGN STAGE
C) Return movement: X= 400mm, Fext= 40KN, T=7seconds
B) Forward working movement: X= 100 mm, Fext= 50 KN, T=3 to 6seconds
A) Forward Initial movement: X= 300mm, Fext= 30KN, T=6seconds
Pext = Fext/ AP
Flow rate for this part
Qext= AP*V ext
For return stroke effective area for pressure will be (AP-AR)
Pext= Fret/ (AP-AR)
Qret= (AP-AR)*V ret

70. : DESIGN STAGE
A) Forward Initial movement: X= 300mm, Fext= 30KN, T=6seconds
Pressure During Extension:
Pext = Fext/ AP = 30000/ (π/4)*(01)2
Pext = 38.2 bar.
Flow rate for this part
V ext =300*10-3 / 6 = 0.05 m/sec
Qext= AP*V ext = (π/4)*(0.1)2* 0.05
Qext = 23.5 lpm (maximum value)

71. : DESIGN STAGE
B) Forward working movement: X= 100 mm, Fext= 50 KN, T=3 to 6seconds
Pressure During Extension:
Pext = Fext/ AP = 50000/ (π/4)*(01)2
Pext = 63.6 bar.
Flow rate for this part
1. Vext =100*10-3 / 3 = 0.0333 m/sec
Qext= AP*V ext = (π/4)*(0.1)2* 0.0333
Qext = 15.7 lpm
2. Vext =100*10-3 / 6 = 0.01667m/sec
Qext= AP*V ext = (π/4)*(0.1)2* 0.01667
Qext = 7.87lpm

72. : DESIGN STAGE
For return stroke effective area for pressure will be (AP-AR)
Pressure During return stroke :
Pext= Fret/ (AP-AR)= 40000/ 5.89 * 10-3
= 67.89 bar (maximum value)
Flow rate for return stroke:
Vret = 400* 10-3 /7 = 0.057 m/sec
Qret= (AP-AR)*V ret
Qret = (5.89 * 10-3) *(0.057)
Qret =20.14 lpm
C) Return movement: X= 400mm, Fret= 40KN, T=7seconds

73. Step-III : SELECTION OF COMPONENTS
Now from system parameters
Maximum working pressure= 67.89 bar
Maximum flow rate= 23.5lpm
Model
Delivery in LPM
At 0
bar
At 35
bar
At 70
bar
P1 8.5 7.1 5.3
P2 12.9 11.4 9.5
P3 17.6 16.1 14.3
P4 25.1 23.8 22.4
P5 39.0 37.5 35.6 P5
Model Capacity
(liters)
T1 40
T2 100
T3 250
T4 400
T5 600
T2
Vane Pump Oil Reservoir
Qret =20.14 lpm
Pext = 38.2 bar.

74. Step-III : SELECTION OF COMPONENTS
D2
DCV
Model Max.
Working
Pressure
(bar)
Flow
Capacity
(LPM)
D1 350 19
D2 210 38
D3 210 105
S1

75. Step-III : SELECTION OF COMPONENTS
Relief Valve
C2
Model Max.
Working
Pressure
(Bar)
Flow
Range
(LPM)
C1 210 15.2
C2 210 30.4
C3 210 76
Check valve
Mode
l
Flow
Capacity
(LPM)
Max.
Working
Pressure
(bar)
R1 11.4 70
R2 19 210
R3 30.4 70
R4 57 105
R3

76. Step-III : SELECTION OF COMPONENTS
D2
DCV
Model Max.
Working
Pressure
(bar)
Flow
Capacity
(LPM)
D1 350 19
D2 210 38
D3 210 105
A5
Model Bore
diameters
(mm)
Rod
diameters
(mm)
A1 25 12.5
A2 40 16
A3 50 35
A4 75 45
A5 100 50