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SRE

up to 350 barup to 97 l/min

Connection housings

Cartridge valve

Flow Control ValvesPressure Compensated

1 2

Cartridge Type

E 5

. 1 1 7

. 6 / 0 5

. 0 6

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1. Description1.1. GENERAL

HYDAC pressure compensatedflow control valves, type SRE,are, in accordance withDIN--ISO 1219, valves foroil--hydraulic systems whichmaintain a constant emergingflow by means of a controlprocess.

The flow rate is largelyindependent of the pressure.The flow rate is determined by afixed orifice (measuring orifice)and can be adjusted over acertain range.Distinct advantages are:

-- unauthorised adjustment notpossible since it is not accessibleonce it is fittedcompact design allows space--saving installation in connectionhousings, control blocks, etc.mounting position optionalrange of connection housingsavailable for adaptation to amultitude of applicationschange of control direction byreversing the unitfour sizes means optimum systemadaptationsimple assembly due to service--friendly cartridge valve technology

1.2. FUNCTIONHYDAC pressure compensatedflow control valves, type SRE, arefixed orifice valves with back--updifferential pressure regulator foroil--hydraulic systems.The differential pressure regulator(compensating piston) basicallyconsists of a control piston,spring, control orifice and theadjustment screw to adjust thecontrol pressure differential.The measuring orifice determinesthe flow adjustment range.Flow from 1 to 2 creates apressure drop across themeasuring orifice. The pistonmoves so that its control positionis in equilibrium with the force of the pressure drop, multiplied bythe control piston area, and thespring force. As the flow rate increases, i. e.increasing pressure drop, thediameter of the control orifice isreduced in accordance with theincreased pressure drop, until aforce equilibrium exists.Due to the continuous adjustmentof the compensating piston inaccordance with the prevailingpressure drop, a constant flow incontrol direction 1 2 isensured.In the reverse direction 2 1 theflow is free. The pressure drop isdetermined by the measuringorifice.

1.3. APPLICATIONHYDAC pressure compensatedflow control valves, type SRE, areparticularly suitable for controllingthe speed of hydraulic cylindersand motors, irrespective of thepressure, and for limiting andcontrolling oil flows. During pumpoperation, the unused pump flow isfed back to the tank via a pressurerelief valve.Particularly suitable applicationsare:fork--liftselevating platformslift tablestail lifts to limit the max. speed of the loading device in accordancewith current accident preventionregulationsflow rate controls for control oilcircuits in main or secondary flowsgeneral flow control functions inhydraulic systems.

1.4. NOTES

When fitting the valves into controlblocks and housings therecommended torque ratings andthe control direction must be takeninto account! (see point 3.1.)In order to avoid resetting the flowrate when fitting the valve, only thescrew slots provided must be usedIf the required control pressuredifferential is not reached, the valveoperates as a speed control valveIn applications with high dynamicload and high cyclic conditions, theparticular application specificationsof the valves must be taken intoaccount, and must be clarified withthe manufacturer at the designstage.

lock nut

screw slot

adjustment screw

measuring orifice

free flow controlled flow

screw slot

control orifice

spring

hardened controlpiston

2

E 5 . 1

1 7 . 6

/ 0 5 . 0

6

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2. TECHNICALSPECIFICATIONS

2.1. GENERAL

2.1.1. Designation and symbolPressure compensated flowcontrol valve

1 2

2.1.3. Type of constructionFixed orifice valve with back--updifferential pressure regulator.Control pressure differentialadjustable.

2.1.4. Type of mountingCartridge valve

2.1.5. Mounting positionOptionalThe installation directiondetermines the direction of thecontrolled flow (1 2)(See also point 3.2.)

2.1.6. WeightSRE 1... 13 gSRE 2... 25 gSRE 3... 49 gSRE 4...112 g

2.1.7. Flow directionFrom 1 to 2 controlled flowFrom 2 to 1 throttled reverse flow

2.1.8. Ambient temperature rangemin. -- 20 Cmax. + 80 C

2.1.9. MaterialsValve body: free--cutting steelControl piston: hardened andground steel

2.1.10. Type of connectionSuitable connection housingswith appropriate cavities areavailable. See separate housingbrochure No. E 5.252../..

Size Threadedconnection

Installationdimensions

SRE1 G 1/4 05520

SRE2 G 3/8 08520SRE3 G 1/2 10520SRE4 G 3/4 12520

Cartridge thread sizeG 1/4 ...SRE1G 3/8 ...SRE2G 1/2 ...SRE3G 3/4 ...SRE4(metric threads on request)

Size1 up to 10 l/min2 up to 20 l/min3 up to 48 l/min4 up to 97 l/min

2.1.2. Model code(also order example) SRE 1 -- G1/4 -- 01 X / 3.8 -- 4

Flow control valve

Series(determined by manufacturer)

Flow rate factor(see also point 2.2.8)

Standard typesStock. no. (= order no.) Model code717583 SRE1--G1/4--01X/1.6710355 SRE1--G1/4--01X/3.8710351 SRE1--G1/4--01X/6.6717586 SRE2--G3/8--01X/2.9717588 SRE2--G3/8--01X/9717590 SRE2--G3/8--01X/15717689 SRE3--G1/2--01X/7717691 SRE3--G1/2--01X/15.5717693 SRE3--G1/2--01X/26717825 SRE4--G3/4--01X/70479390 SRE4--G3/4--01X/88

Type01 = technical specifications as per this brochure

Flow rate setting value (l/min)-- if no details are specified, the valve is not set, but the flow rate is withinthe setting range i.e. VK 3.8 = flow rate is between 3.8 and 4.8 l/min

-- if a flow rate setting is required, please indicate value when ordering.Delivery for pre--set valves is longer and the price is higher.

Please quote stock number when ordering.Delivery for non--standard valves is longer and the price is higher.

3

E 5

. 1 1 7

. 6 / 0 5

. 0 6

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SW 1 SW 2 adjustment range Tapprox. (mm)

SRE 1 2 4 1

SRE 2 3 6 2.5

SRE 3 3 6 3

SRE 4 4 6 3

2.2. HYDRAULIC DETAILS2.2.1. Nominal pressure

pN = 350 baron all ports pmax 2 1: 250 bar

2.2.2. Working pressure range p = the required controlpressure differential p 1 -- p2(see point 2.2.8.)If the differential pressure is lower,the valve operates as a speedcontrol valve.p1max. = 350 bar

2.2.3. Operating fluidHydraulic oil to DIN 51524,parts 1 and 2.

2.2.4. Fluid temperature rangemin. --20 Cmax. +80 C

2.2.5. Viscosity rangemin. 2.8 mm 2 /smax. 380 mm 2 /s

2.2.6. FiltrationMax. permissible contaminationlevel of the operating fluid toISO 4406 Class 21/19/16(NAS 1638, class 10) or cleaner.We therefore recommend a filterwith a minimum retention rate of 20 100The installation of a filter and theregular replacement or cleaningof the filter element ensures thecorrect functioning of the valves,reduces wear and tear andincreases the service life.

2.2.7. Flow settingThe flow setting can only be adjusted before the valve is installed.To change the flow rate setting, the lock nut must be unscrewed.Turn the adjustment screw in the appropriate direction(+ increase flow; -- reduce flow) to adjust the flow rate.Subsequently, the adjustment screw is secured by means of the lock nut.Please note:The edging on both sides of the valve body limits the adjustment range.Do not force the lock nut past the adjustment limit.

lock nut SW 2

adjustment screw SW 1

flow rate

4

E 5 . 1

1 7 . 6

/ 0 5 . 0

6

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2.2.8. Flow rate

2.2.9. Flow rate, dependent onpressureQ-- p graphmeasured at = 72 mm 2 /s andtoil = 30 C

The above flow rate values are standard values.Different flow rate values are available within the range 0.3 -- 97 l/min.Standard manufacturers setting is at p=100 bar

2.2.10. p--Q graphPressure differential pdependent on flow rate Qmeasured at = 72 mm 2 /s andtoil = 30 CVK= flow rate factorpmax 2 1: 250 bar

3

Size Flow ratefactor

VK

Flow rateadjustmentrange(l/min)

Required controlpressure differential(bar)p = (p1 -- p2)

0.6 0.6 -- 0.7 10 -- 121 1.0 -- 1.3 10 -- 121.6 1.6 -- 2.1 10 -- 12

SRE 12.3 2.3 -- 3.0 10 -- 12

3.8 3.8 -- 4.8 10 -- 156.6 6.6 -- 8.6 10 -- 151 1.0 -- 1.5 8 -- 151.5 1.5 -- 2.4 8 -- 152.9 2.9 -- 4.6 8 -- 15

SRE 25 5.0 -- 7.5 10 -- 159 9.0 -- 13.0 12 -- 18

15 15.0 -- 23.0 12 -- 181.7 1.7 -- 2.1 8 -- 122.8 2.8 -- 3.8 8 -- 124.5 4.5 -- 5.5 8 -- 15

7 7.0 -- 9.2 8 -- 15SRE 310 10.0 -- 12.5 8 -- 1515.5 15.0 -- 18.0 8 -- 1526 25.5 -- 30.0 8 -- 1535 35.0 -- 42.0 10 -- 1827 27.0 -- 29.4 12 -- 1540 40.0 -- 42.9 12 -- 1546 46.0 -- 49.9 12 -- 15

SRE 455 55.0 -- 59.9 13 -- 1770 70.0 -- 78.9 15 -- 1888 88.0 -- 97.0 18 -- 21

5

E 5

. 1 1 7

. 6 / 0 5

. 0 6

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3. DIMENSIONS3.1. CARTRIDGE VALVE

TorqueSRE1 3 -- 5 NmSRE2 5 -- 8 NmSRE3 8 -- 12 NmSRE4 12 -- 18 Nm

3.2. INSTALLATIONDIMENSIONS

The installation dimensions listed above are minimum values for pipe threads and malethreads to DIN 3852

4. NOTEThe information in this brochure relates to the operating conditions and applicationsdescribed. For applications or operating conditions not described, please contact therelevant technical department.Subject to technical modifications.

c o n t r o l l e d f l o w

c o n t r o l l e d f l o w

e min

e min e min

e min

f f

g g

b m i n

a m i n

d m i n

c m i n

3

Size A B C D E F G H

SRE1 G 1/4 11.0 10.0 26.0 14.0 6.5 1.5 1.5

SRE2 G 3/8 14.0 13.0 30.0 14.5 9.5 1.5 1.5

SRE3 G 1/2 18.0 16.0 37.0 16.0 13.0 2.0 2.0

SRE4 G 3/4 23.0 20.0 51.0 21.0 20.0 4.0 2.0

Size amin.

bmin.

cmin.

dmin.

emin.

f g hmax.

SRE1 33.0 9.0 26.0 16.0 5.0 25.0 G 1/4 1.5

SRE2 34.0 11.5 30.0 16.5 7.0 28.0 G 3/8 2

SRE3 40.0 15.0 37.0 18.0 10.0 34.0 G 1/2 2.5

SRE4 51.0 24.0 51.0 24.0 12.0 42.0 G 3/4 2.5

6

E 5 . 1 1 7 . 6 / 0 5 . 0 6