1 electro – proportional valves. 2 hydraulic control technology closed loop proportional...
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1
ELECTRO –
PROPORTIONAL
VALVES
2
HYDRAULIC CONTROL TECHNOLOGY
Closed Loop Proportional
Incre
asin
gP
erf
orm
an
ce
Servo valve
Hybrid series
Proportional Valves
ConventionalValves
Open LoopProportional
New Series Proportional valves
3
COMPARISON BETWEEN CONVENTIONAL AND PROPORTIONAL
VALVES
Conventional
Mechanical
Single
In Steps
Complex
Large
Complicated
Not Available
SL.
No.
1
2
3
4
5
6
7
Description
Setting
Stage Control
Slope Control
Circuit
Size of Blocks, Pipes
Power Saving Circuit
Feedback
Proportional
Electrical
Multiple
Smooth Slope
Simple
Small
Simple
Available
4
DEVELOPMENT OF ELECTRO - PROPORTIONAL VALVES
Year 1965 ~ 1970 1975 ~ 1980 1980 ~ 1985 1990 ~
Pressure Control
&
Flow Control Valves
Combination of Pressure
& FlowControl
Valves
Power Matching Systems.
Directional & Flow Control Valves
EH- Series
Pressure & Flow , Directional & Flow Control Valves.
Power Matching Systems
SALIENT FEATURES OF ELECTRO PROPORTIONAL
VALVESBasic Structure
Solenoid
Just Like Conventional
ValveSimple High
Reliability
Wet Armature
Type
Longer Service
Life
Easy to Use
Easy to Maintain
Directly Operated
Type
Powerful Driving
High Resistance
Against Contamination
With Current Feedback Function,
DitherAmplifier Stable Control
6
DEVICES FOR THE PROPORTIONAL CONTROL
Setting Device
Manual Dialing
Program Control
Computer Control
Power Amplifier
Prop. Valve
DC input type
DC input with feedback type
Slow up – down.
Sensor
Pilot Relief Valve Relief Valves Relieving &
Reducing valves Flow control
(& check) valves Throttle Valves Power Saving
Valves Direction & Flow
control Valves
The Sensor detects the Controlled Pressure, Flow Rate and Speed etc., and converts it to electric signal.
Feedback signal in Closed Loop
Circuit
Indication
DC VOLTAGE
DC CURRENT
7
SIGNAL SEQUENCE
Control Power Supply
Command Signal
Amplifier ActuatorProp. Valve
Hydraulic Power Supply
Sensor
Control Panel0~10V
8
PRINCIPLE OF OPERATION
D C Current
Magnetic Force
Spring Force
Plunger Coil
( Schematic Diagram of Solenoid )
9
PRINCIPLE OF SOLENOID OPERATION
ELECTRO MAGNET
PERMANENT MAGNET
PLUNGERCOIL
NO ELECTRIC CURRENT
ELECTRIC CURRENT
Magnetic Field created which must travel through air.
ELECTRIC CURRENT
1.) Attracts Plunger to an equilibrium position.
2.) Creates an output force.
3.) so that magnetic field can pass 100% through the iron.
10
PRINCIPLE OF BASIC SOLENOID OPERATION
11
COMPARISON : FORCE V/S STROKE
Conventional
Proportional
Stroke
Fo
rce
Stroke
Fo
rce
Stroke
Fo
rce
Stroke
Fo
rce
30 %
70 %
100 %
30 %50 %
70 %100 %
12
COMPARISON : FORCE V/S STROKE
Stroke Stroke
Fo
rce
Fo
rce
Spring Curve
Spring CurveConventional Proportional
30 %
50 %
70 %
100 %
30 %
70 %
100 %
13
COMPARISON OF SOLENOID CONSTRUCTION
CONVENTIONAL SOLENOID
PROPORTIONAL SOLENOID
COIL
COIL
ARMATURE
ARMATURE
Air Gap
Air Gap
14
CONSTRUCTION DETAILS OF PROP. SOLENOID
Spring
Coil
Plunger
Air Vent
Air Gap
Iron CoreManual Adj. Screw
Bearing
16
03 06 10
06 10
03 06
03 06 10
0301
0604
Kgf/Cm2
245 245245245 245245
Pilot Relief Valves
Relief Valves
Reducing & Relieving Valves
Flow Control (& Check)Valves
Flow Control & Relief Valves
Directional & Flow Cont.Valves
High Response Type Directional & Flow Cont.Valves 157
EH S
erie
sE
Serie
s
Pilot Relief Valves
Relief Valves
Reducing & Relieving Valves
Flow Control (& Check)Valves
Flow Control & Relief Valves
Directional & Flow Cont.Valves
245245245206245
245
245
EBG 03 06 10
06 10
03 06 1002
03 06
03 06 10
03 06 10
03 06
03 0604
1 2 5 10 20 50 100 200 300
Maximum FlowMaximum Operating PressureValve Type
L /min3 30 500 1000
PROPORTIONAL HYDRAULIC CONTROL - RANGE
17
STEP RESPONSEFig. 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
1000 X 1 = 6.6 Cycles / Sec ( Or 6.6 Hz )
150
STEP SIGNAL 0 ~ 100 %
80 0 70TIME ( ms )
0
50
100
STEP SIGNAL 25 ~ 100 %
0
25
100
75
50 0 40TIME ( ms )
ST
RO
KE
%
ST
RO
KE
%
STEP SIGNAL 10 ~ 90 %
TIME ( ms )70 0 60
0
50
90
ST
RO
KE
%
STEP RESPONSE : A RESPONSE MADE WHEN THE INPUT SIGNAL SUDDENLY CHANGES FROM A GIVEN VALUE TO ANOTHER GIVEN VALUE
18
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)
19
PHASE LAG
Cyclic Input
– The time required for the output to recreate the input command. Measured in Degrees.
Cyclic Out put
Phase Lag in Degrees
90°
Time
90° Phase Lag
TimePhase Lag in Degrees
20
PROPORTIONAL ELECTRO – HYDRAULIC PILOT RELIEF VALVE
FREQUENCY RESPONSEFrequency ( Hz )
2 L
30 cm
-10-20-30
0- 20
- 40- 60- 80
-100
-120
-140
-160-180
0.1 0.2 0.4 0.7 1 2 4 7 10 20 40 70G
ain
( d
B )
Ph
as
e (
de
g. )
Flow Rate Pressure Trapped Oil Volume Viscocity
: : : :
/ min 80 ± 16 Kgf /
Cm2 3
30 cSt
Phase
Gain
21
HYSTERESIS
0 200 400 600 800 0 200 400 600 800
200
180
160
140
120
100
80
60
40
20
Pre
ssu
re
Kg
f /
Cm
2
Pre
ssu
re
Kg
f /
Cm
2
Current ( mA ) Current ( mA )
200
180
160
140
120
100
80
60
40
20
Hysterisis without Dither
Hysteresis with Dither
Dead Band Dead Band
22
PROPORTIONAL ELECTRO – HYDRAULIC PILOT RELIEF VALVE
PLUNGER
SPRING
POPPETSEAT SPRING
Pr. Adj. Screw for Safety valvePRESSURE
PORTTANK PORT
COIL
PLUNGER
AIR VENT
MANUAL PR. ADJ. SCREW
IRON CORE
Without Safety Valve
With Safety Valve
23
PROPORTIONAL ELECTRO – HYDRAULIC PILOT RELIEF VALVE
minFlow Rate Trapped Oil Volume
Viscocity
: :
:
2 L /
40 cm3
30 cSt
Time
90
70
50
30
10
0.2 Sec
Step Signal
Pre
ssu
re
Kgf / Cm2
STEP RESPONSE
24
PROPORTIONAL ELECTRO – HYDRAULIC PILOT RELIEF VALVE
FLOW RATE VS PRESSURE : 30 cSt
Flow Rate
Viscosity
250235
220
160145130
7055
40
1 20 L / min
B
C
A
Pre
ssu
re
Kg
f /
Cm
2
25
PROPORTIONAL ELECTRO – HYDRAULIC PILOT RELIEF VALVE
FREQUENCY RESPONSEFrequency ( Hz )
2 L
30 cm
-10-20-30
0- 20
- 40- 60- 80
-100
-120
-140
-160-180
0.1 0.2 0.4 0.7 1 2 4 7 10 20 40 70G
ain
( d
B )
Ph
as
e (
de
g. )
Flow Rate Pressure Trapped Oil Volume Viscocity
: : : :
/ min 80 ± 16 Kgf /
Cm2 3
30 cSt
Phase
Gain
26
PROPORTIONAL ELECTRO – HYDRAULIC PILOT RELIEF VALVE
CONTROL PRESSURE VS INPUT CURRENT 250
200
150
100
50
00 200 400 600 800 1000
C
B
Input Current mA
A
Pre
ssu
re
Kg
f /
Cm
2
27
PROPORTIONAL ELECTRO – HYDRAULIC RELIEF VALVE
PROPORTIONAL PILOT RELIEF VALVE WITH SAFETY VALVE
SLEEVE SEAT
SPRING
POPPET
AIR VENT
MANUAL PR. ADJ. SCREW
PR. PORT TANK PORTVENT PORT
Graphic Symbol
28
PROPORTIONAL ELECTRO – HYDRAULIC RELIEF VALVE STEP
RESPONSE200
160
120
80
40
0.2s
Flow Rate : 200 L / min )
Time
Step Signal
Pre
ssu
re
Kgf/Cm2
Loading Volume Viscocity
:
:
1 ltr.
30 cSt
29
COMPARISON OF CONVENTIONAL & PROPORTIONAL PRESSURE CIRCUIT
Conventional Circuit
Proportional CircuitSwitch ON Sol. a – d
to get 4 different pressures
Only One Valve is required ., By changing the Input Current, the Pressure can be changed.
31
PROPORTIONAL ELECTRO – HYDRAULIC FLOW CONTROL VALVE
INLET PORT
OUTLET PORT
DRAIN PORT
SPOOL ORIFICE SLEEVE
PR. COMPENSATOR PISTON
40 Series ( Direct Type )
Graphic Symbol
O
M
34
STEP RESPONSE
Time
125 L / min
60 L / min
0.2s
Step Signal
140L / min
120
100
80
60
40
20
0
Flo
w R
ate
40 Ohm 10 Ohm
Flo
w R
ate
125 L min /
60 L / min
0.2s
Step Signal
150L / min
125
100
75
50
25
0
Time
35
FREQUENCY RESPONSE
0- 10- 20
0.2 0.7 1 2 4 710 300
- 20- 40- 60- 80
- 100- 120- 140- 160- 180
0.1
Gain
Phase
Frequency ( Hz )
Ph
ase
(d
eg
.)
Gain
(d
B)
Input Current : 460 ± 70 mA
Pressure : 70 Kgf / Cm2
40 Ohm
37
COMPARISON OF CONVENTIONAL & PROPORTIONAL FLOW CIRCUITS
Signal
BackwardForward
Intermediate Speed
Low Speed
High Speed
PUMP
BackwardForward
PUMP
EFG-* -
Conventional
Proportional
Sol. 1
Sol. 2
Sol. 3
Sol. 4
Sol. 1
Sol. 2
HEAT GENERATED
= P x Q x 860 Kcal / Hr
612
= 40 x 40 x 860
612
= 2248 Kcal / Hr
LOAD SENSING - COMPARISON OF HEAT GENERATION
38
LOAD SENSING - COMPARISON OF HEAT GENERATION
39
Increase pressure
VENT LINE
REMOTE CONTROL RELIEF VALVE
Set At
100 BarP
T
LOAD SENSING - COMPARISON OF HEAT GENERATION
40
w
Load Pressure = 10 Kgf / Cm2
Flow Control Valve Set
At 100 Bar
Load Pr. + 5 Kgf/Cm2
(10 + 5 = 15 Kfg/Cm2 )
P
T
41
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
42
CONVENTIONAL POWER SAVING VALVE
OUTLET PORTINLET PORT TANK PORT
DRAIN PORT
RELIEF VALVE
FLOW CONTROL VALVE
TANK PORT OUTLET PORT
43
PROPORTIONAL ELECTRO – HYDRAULIC RELIEF & FLOW CONTROL VALVE
INLET PORT DRAIN PORT
40 - 10 Series
PROPORTIONAL PILOT RELIEF VALVE WITH SAFETY VALVE
FLOW CONTROL SOLENOID
Power loss
Energy Saving
Power loss
Power loss
Power loss
Energy SavingEnergy Saving
Conventional Circuit
• Flow Matching Circuit
• Load Sensing Circuit
Proportional Circuit
Q
P
Q
P
Q
P
Q
P
45
POWER SAVING CIRCUIT
46
PROPORTIONAL ELECTRO – HYDRAULIC DIRECTIONAL AND FLOW CONTROL
VALVE
Max. Op. Pr. : 250 Kgf / Cm2
Max. Flow : 01 30 L/ min
03 60 L/ min
48
PROPORTIONAL ELECTRO – HYDRAULIC DIRECTIONAL AND FLOW CONTROL VALVE
A B
P T
A B
P T
0 200 400 600 800 10002004006008001000 mAInput Current
L/ min
0
20
40
60
80
100
120
Flo
w R
ate
INPUT CURRENT V/S FLOW
49
PROPORTIONAL ELECTRO – HYDRAULIC DIRECTIONAL AND FLOW CONTROL VALVE
PRESSURE DIFFERENCE V/S FLOW
A B
P T
A B
P T
700 mA
140
120
80
40
40
80
120
140
L /min
Valve Pres. Diff.
Flow
Rat
eValve Pres. Diff.
70 140 210 245
70 140 210 245
L / min
Flow
Rat
e
750 mA
700 mA
600 mA
750 mA
600 mAKgf / Cm2
Kgf / Cm2
51
LINEAR VARIABLE DIFFERENTIAL TRANSFORMER ( LVDT )
PRIMARY COIL
SECONDARY COIL
SECONDARY COIL
INPUT
OUTPUT
MOVEMENT
IRON CORE
52
HYBRID SERIES PROPORTIONAL VALVES
Pressure display panel (option)
Power Amplifier
Pressure Sensor Incorporated
Alarm Signal Output
Voltage Output for Pr. monitor
Command Signal Voltage Input
24 V DC Power Supply
Proportional Electro Hydraulic Relief Valve
54
INSTALLATION REQUIREMENT
Air Vent
SOL
SO
L
Air Vent
Air Vent
SO
L
SOL
Air Vent
SO
L
Air Vent Air Vent
SO
L
GOOD EXAMPLE
BAD EXAMPLE
55
TYPICAL APPLICATIONS
ELEVATORS
ROLLING MILLS
PLANERS
INJECTION MOULDING MACHINES
PRESSES
SURFACE GRINDING MACHINES
55
Proportional Direction and Flow Control Valve with LVDT
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