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ELECTRO –
PROPORTIONAL
VALVES
1
HYDRAULIC CONTROL TECHNOLOGY
Increasing
Performance
Servo valve
New Series
Proportional valves
Hybrid series
Closed Loop
Proportional
Proportional Valves
Open Loop
Proportional
Conventional
Valves
2
COMPARISON BETWEEN
CONVENTIONAL AND PROPORTIONAL VALVES
SL.
No.
Description
Conventional
Proportional
1
Setting
Mechanical
Electrical
2
Stage Control
Single
Multiple
3
Slope Control
In Steps
Smooth Slope
4
Complex
Simple
5
Circuit
Size of Blocks, Pipes
Large
Small
6
Power Saving Circuit
Complicated
Simple
7
Feedback
Not Available
Available
3
DEVELOPMENT OF
ELECTRO - PROPORTIONAL VALVES
Year 1965 ~ 1970
Pressure
Control
&
Flow
Control
Valves
1975 ~ 1980
Combination
of Pressure
&
FlowControl
Valves
1980 ~ 1985
Power
Matching
Systems.
Directional &
Flow Control
Valves
1990 ~
EH- Series
Pressure &
Flow ,
Directional &
Flow Control
Valves.
Power
Matching
Systems
4
SALIENT FEATURES OF
ELECTRO PROPORTIONAL VALVES
Basic
Structure
Just Like
Conventional
Valve
Simple
Solenoid
Wet
Armature
Type
Longer
Service
Life
Directly
Operated
Type
Amplifier
Powerful
Driving
With Current
Feedback Function,
Dither
High
Reliability
Easy to Use
Easy to
Maintain
High
Resistance
Against
Contamination
Stable Control
DEVICES FOR THE PROPORTIONAL CONTROL
Setting Device
Manual
Dialing
Program
Control
Computer
Control
DC VOLTAGE
Power
Amplifier
DC input
type
DC input
with
feedback
type
Slow up –
down.
DC CURRENT
Feedback signal in
Closed Loop Circuit
Prop. Valve
Pilot Relief Valve
Relief Valves
Relieving &
Reducing valves
Flow control
(& check) valves
Throttle Valves
Power Saving
Valves
Direction & Flow
control Valves
Indication
Sensor
The Sensor
detects the
Controlled
Pressure,
Flow Rate
and Speed
etc., and
converts it
to electric
signal.
6
SIGNAL SEQUENCE
Control Power
Supply
Hydraulic
Power Supply
Control Panel
Command
Signal
0~10V
Amplifier
Prop.
Valve
Actuator
Sensor
7
PRINCIPLE OF OPERATION
Plunger
Coil
Spring Force
Magnetic Force
D C Current
( Schematic Diagram of Solenoid )
8
PRINCIPLE OF SOLENOID OPERATION
ELECTRO MAGNET
PERMANENT MAGNET
9
PRINCIPLE OF BASIC SOLENOID OPERATION
NO ELECTRIC
CURRENT
PLUNGER
COIL
ELECTRIC
CURRENT
ELECTRIC
CURRENT
Magnetic Field created
which must travel
through air.
1.) Attracts Plunger to an
equilibrium position.
2.) Creates an output force.
3.) so that magnetic field can
pass 100% through the iron.
10
COMPARISON : FORCE V/S STROKE
Proportional
Force
Force
Conventional
Stroke
100 %
70 %
100 %
70 %
30 %
50 %
30 %
Stroke
Force
Force
Stroke
Stroke
11
COMPARISON : FORCE V/S STROKE
Proportional
Conventional
Spring Curve
Spring Curve
100 %
70 %
30 %
Stroke
50 %
Force
Force
100 %
70 %
30 %
Stroke
12
COMPARISON OF SOLENOID CONSTRUCTION
Air Gap
COIL
CONVENTIONAL
SOLENOID
ARMATURE
Air Gap
COIL
PROPORTIONAL
SOLENOID
ARMATURE
1
3
CONSTRUCTION DETAILS OF PROP. SOLENOID
Manual Adj.
Screw
Iron Core
Air Vent
Coil
Bearing
Spring
Air Gap
Plunger
14
PROPORTIONAL HYDRAULIC CONTROL - RANGE
Maximum Flow
Valve Type
Maximum
Operating
Pressure
Kgf/Cm2
1
2
3
5
10
20 30
50
100
200 300 500
1000
L /min
EH Series
Pilot Relief Valves
245
Relief Valves
245
Reducing & Relieving Valves 245
Flow Control (& Check)Valves 245
Flow Control & Relief Valves 245
Directional & Flow Cont.Valves 245
High Response Type
Directional & Flow Cont.Valves 157
03
06
01
06
10
10
03
06
03
06
10
03
04
06
E Series
Pilot Relief Valves
245
Relief Valves
245
Reducing & Relieving Valves 245
206
Flow Control (& Check)Valves
245
Flow Control & Relief Valves
Directional & Flow Cont.Valves
245
245
EBG
03
06
W
02
06
10
10
03
06
W
03
06
W
W
03
06
10
W
W
03
06
10
03
06
03 04
10
06
16
STEP RESPONSE
STEP SIGNAL 0 ~ 100 %
STROKE %
100
50
Fig. Shows the Valve requires
80 ms to go from 0 to 100% Stroke and
70 ms to fully close.
i.e., 150 ms is required to complete one cycle.
150 ms
- 1 Cycle
1000ms ( 1 Sec ) - ? Cycles
0
80
0
TIME ( ms )
70
1000 X 1 = 6.6 Cycles / Sec ( Or 6.6 Hz )
150
STEP SIGNAL 10 ~ 90 %
STEP SIGNAL 25 ~ 100 %
90
75
STROKE %
STROKE %
100
25
0
50
0
TIME ( ms )
40
50
0
70
0
TIME ( ms )
60
STEP RESPONSE : A RESPONSE MADE WHEN THE INPUT SIGNAL
SUDDENLY CHANGES FROM A GIVEN VALUE TO ANOTHER GIVEN VALUE
17
FREQUENCY RESPONSE
– Frequency
•Is the number of times any
action occurs in a given
measure of time.
Unit is Hz (Cycles per Second)
– Amplitude Response ( Gain )
•Is a ratio of output change to
input change.
Measured in dB (Decibels)
18
PHASE LAG
– The time required for the output to recreate
the input command. Measured in Degrees.
Cyclic Input
Cyclic Out put
Phase Lag in
Degrees
Time
90° Phase Lag
90°
Phase Lag in
Degrees
Time
19
PROPORTIONAL ELECTRO – HYDRAULIC
PILOT RELIEF VALVE
 FREQUENCY RESPONSE
0
- 20
- 40
- 60
- 80
-100
-120
-140
-160
-180
0.1 0.2 0.4 0.7 1
2
4
7 10
20
-10
-20
-30
Gain ( dB)
Phase ( deg.)
Frequency ( Hz)
40 70
Gain
Phase
Flow Rate
: 2 L / min
Pressure
: 80 ± 16 Kgf / Cm2
Trapped Oil Volume : 30 cm 3
Viscocity
: 30 cSt
20
HYSTERESIS
Hysteresis
with Dither
200
200
180
180
160
160
Pressure Kgf / Cm2
Pressure Kgf / Cm2
Hysterisis
without Dither
140
120
100
80
60
40
20
0
200
400
600
Current ( mA )
Dead Band
800
140
120
100
80
60
40
20
0
200
400
600
800
Current ( mA )
Dead Band
21
PROPORTIONAL ELECTRO – HYDRAULIC
PILOT RELIEF VALVE
PLUNGER
COIL
SPRING
With
Safety Valve
POPPET
SEAT
PLUNGER
SPRING
AIR VENT
MANUAL PR.
ADJ. SCREW
IRON CORE
TANK
PORT
PRESSURE
PORT
Pr. Adj.
Screw for
Safety valve
Without
Safety Valve
22
PROPORTIONAL ELECTRO – HYDRAULIC
PILOT RELIEF VALVE
 STEP RESPONSE
Flow Rate : 2 L / min
Trapped Oil : 40 cm3
Volume
Viscocity : 30 cSt
Kgf / Cm2
90
Pressure
70
50
30
0.2 Sec
Step Signal
10
Time
23
PROPORTIONAL ELECTRO – HYDRAULIC
PILOT RELIEF VALVE
FLOW RATE VS PRESSURE
Viscosity : 30 cSt
A
250
235
Pressure Kgf / Cm2
220
B
160
145
130
C
70
55
40
0
1
2
L / min
Flow Rate
24
PROPORTIONAL ELECTRO – HYDRAULIC
PILOT RELIEF VALVE
 FREQUENCY RESPONSE
0
- 20
- 40
- 60
- 80
-100
-120
-140
-160
-180
0.1 0.2 0.4 0.7 1
2
4
7 10
20
-10
-20
-30
Gain ( dB)
Phase ( deg.)
Frequency ( Hz)
40 70
Gain
Phase
Flow Rate
: 2 L / min
Pressure
: 80 ± 16 Kgf / Cm2
Trapped Oil Volume : 30 cm 3
Viscocity
: 30 cSt
25
PROPORTIONAL ELECTRO – HYDRAULIC
PILOT RELIEF VALVE
 CONTROL PRESSURE VS INPUT CURRENT
250
A
Pressure Kgf / Cm2
200
150
100
B
50
0
C
0
200
400
600
800
1000
Input Current mA
26
PROPORTIONAL ELECTRO – HYDRAULIC
RELIEF VALVE
PROPORTIONAL
PILOT RELIEF
VALVE WITH
SAFETY VALVE
AIR VENT
MANUAL PR.
ADJ. SCREW
SLEEVE SEAT
SPRING
Graphic Symbol
POPPET
VENT PORT PR. PORT
TANK PORT
27
PROPORTIONAL ELECTRO – HYDRAULIC
RELIEF VALVE
 STEP RESPONSE
Kgf/Cm2
200
Pressure
160
120
0.2s
80
Step Signal
40
Time
Flow Rate :
Loading
Volume
Viscocity
200 L / min )
: 1 ltr.
: 30 cSt
28
COMPARISON OF CONVENTIONAL &
PROPORTIONAL PRESSURE CIRCUIT
Conventional Circuit
Switch ON Sol. a – d to get
4 different pressures
Proportional Circuit
Only One Valve is required
., By changing the Input
Current, the Pressure can
be changed.
29
PROPORTIONAL ELECTRO – HYDRAULIC
FLOW CONTROL VALVE
40W Series
( Direct Type )
PR. COMPENSATOR PISTON
INLET PORT
DRAIN PORT
Graphic
Symbol
OUTLET PORT
O
M
SPOOL
ORIFICE SLEEVE
31
STEP RESPONSE
L / min
140
120
100
80
60
40
20
0
10 Ohm
L / min
150
125 L / min
125 L / min
125
60 L / min
0.2s
Step Signal
Time
Flow Rate
Flow Rate
40 Ohm
100
75
50
25
0
60 L / min
0.2s
Step Signal
Time
34
FREQUENCY RESPONSE
40 Ohm
-
0
- 20
- 40
- 60
- 80
100
120
140
160
180
0
- 10
- 20
0.1 0.2
0.7 1
Input Current : 460
2
4
7 10
30
Gain
Gain ( dB )
Phase (deg. )
Frequency ( Hz )
Phase
± 70 mA
Pressure : 70 Kgf / Cm2
35
COMPARISON OF CONVENTIONAL &
PROPORTIONAL FLOW CIRCUITS
Forward
Forward
Backward
Sol. 1
Sol. 2
Intermediate
Speed
Sol. 3
Sol. 1
Backward
Sol. 2
EFG-* Signal
Sol. 4
PUMP
PUMP
Low
Speed
High
Speed
Conventional
Proportional
37
LOAD SENSING COMPARISON OF HEAT GENERATION
HEAT GENERATED
= P x Q x 860 Kcal / Hr
612
= 40 x 40 x 860
612
= 2248 Kcal / Hr
38
LOAD SENSING COMPARISON OF HEAT GENERATION
VENT
LINE
Increase pressure
P
Set
At
100
Bar
T
REMOTE CONTROL
RELIEF VALVE
39
LOAD SENSING COMPARISON OF HEAT GENERATION
w
Load Pr. + 5 Kgf/Cm2
(10 + 5 = 15 Kfg/Cm2 )
Load Pressure = 10 Kgf / Cm2
Flow Control
Valve
P
Set
At
100
Bar
T
40
LOAD SENSING COMPARISON OF HEAT GENERATION
HEAT GENERATED
= P x Q x 860 Kcal / Hr
612
= 40 x 15 x 860
612
= 843 Kcal / Hr
41
CONVENTIONAL POWER SAVING VALVE
FLOW CONTROL
VALVE
RELIEF VALVE
INLET PORT
TANK
PORT
DRAIN
PORT
OUTLET PORT
42
PROPORTIONAL ELECTRO – HYDRAULIC
RELIEF & FLOW CONTROL VALVE
FLOW CONTROL
SOLENOID
40W - 10W Series
PROPORTIONAL
PILOT RELIEF
VALVE WITH
SAFETY VALVE
INLET PORT
TANK
PORT
DRAIN
PORT
OUTLET PORT
43
POWER SAVING CIRCUIT
Conventional
Circuit
Q
Power
loss
P
Proportional Circuit
Energy Saving
Q
Q
Energy Saving
Power
loss
Power
loss
P
P
• Flow Matching
Circuit
Q
Energy Saving
Power
loss
P
• Load Sensing
Circuit
45
PROPORTIONAL ELECTRO – HYDRAULIC
DIRECTIONAL AND FLOW CONTROL VALVE
Max. Op. Pr. : 250 Kgf / Cm2
Max. Flow : 01  30 L/ min
03  60 L/ min
46
PROPORTIONAL ELECTRO – HYDRAULIC
DIRECTIONAL AND FLOW CONTROL VALVE
INPUT CURRENT V/S FLOW
Flow Rate
L/ min
120
100
AB
A B
80
P T
P T
60
40
20
0
1000 800 600 400 200 0 200 400 600 800 1000
mA
Input Current
48
PROPORTIONAL ELECTRO – HYDRAULIC
DIRECTIONAL AND FLOW CONTROL VALVE
 PRESSURE DIFFERENCE V/S FLOW
L /min
140
750 mA
Flow Rate
120
245 210 140
80
600 mA
70
70
600 mA
140
P T
700 mA
750 mA
120
140
Kgf / Cm2
Flow Rate
80
210 245
Valve Pres. Diff.
40
A B
P T
700 mA
40
Valve Pres. Diff.
Kgf / Cm2
A B
L / min
49
LINEAR VARIABLE DIFFERENTIAL TRANSFORMER
( LVDT )
INPUT
SECONDARY
COIL
PRIMARY
COIL
SECONDARY
COIL
MOVEMENT
IRON CORE
OUTPUT
51
HYBRID SERIES PROPORTIONAL VALVES
24 V DC Power
Supply
Command
Signal
Voltage
Input
Pressure display panel (option)
Power Amplifier
Pressure Sensor
Incorporated
Voltage
Output for
Pr. monitor
Alarm Signal
Output
Proportional Electro Hydraulic Relief Valve
52
INSTALLATION REQUIREMENT
Air Vent
SOL
Air Vent
SOL
GOOD EXAMPLE
Air Vent
SOL
Air Vent
SOL
SOL
SOL
BAD EXAMPLE
Air Vent
Air Vent
54
TYPICAL APPLICATIONS
ELEVATORS
ROLLING MILLS
PLANERS
INJECTION MOULDING MACHINES
PRESSES
SURFACE GRINDING MACHINES
55
Proportional Direction and Flow Control Valve
with LVDT
55