1 electro – proportional valves. 2 hydraulic control technology closed loop proportional...

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


0

25

100

75

50 0 40TIME ( ms )

ST

RO

KE

%

ST

RO

KE

%


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


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


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


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


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


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


39

Increase pressure

VENT LINE

REMOTE CONTROL RELIEF VALVE

Set At

100 BarP

T


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


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

1 electro – proportional valves. 2 hydraulic control technology closed loop proportional...

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