Catalogoe directional control valve...

Directional controlvalve HV08Proportional valve for systemswith fixed or variable pumps

Catalogue 9129 8543-02 GBCatalogue 9129 8543-06 USDecember 1998

Directional control valve HV08

2

This catalogue has been designed to give an overview of theHV08 valve and to show how easily it can be customized tomeet your needs. Apart f rom general info rmation and basictechnical data, the catalogue contains descriptions of thevariety of options available for the di fferent functions within thevalve. After you have studied the options and made your selec-tion, we will tailor your valve to meet your operating and cont rolcriteria.

Each function a rea is given as a subheading, followed by abrief description. When options a re available for the function,an “Item number” in squa re brackets follows the subheading,e.g. Pressure relief valve [15] . This is followed by a series of

coded options, e.g . PLS, PLB, PPS, PPB, Y1 , together with abrief description of what each code rep resents. Alte rnatively,one or more pressure, flow or voltage options a re given.

On page 11 is a general ci rcuit diagram showing the basicfunctions of the HV08 valve, together with the item numbers orletters used to rep resent them. Naturall y, the same item num-bers or letters a re used in all sub-ci rcuit diagrams that appearelsewhere in the catalogue in conjunction with descriptions ofthe respective functions. All sub-ci rcuit diagrams have beenextracted f rom the general circuit diagram. Please note that,unless stated otherwise, all sections and views of the valveshave been drawn as seen from the inlet section.

who will either help personally or refer you to the appropriateproduct specialist. The info rmation in your CSF will be ente redinto our computerized valve specification p rogram, which initi-ates the assembly p rocess and generates a unique product IDnumber that is subsequently stamped into the data plate onyour valve. Your valve specifications remain on our database tofacilitate rapid identification of your valve in the event of subse-quent re-o rdering or servicing matters.

Catalogue layout

How to order your valveThe next step is to fill in a “Customer Specification Form” (CSF)to specify the options and characteristics you wish to be inco r-porated into your valve. The CSF contains the same item num-bers that appear in squa re brackets in this catalogue. To spec-ify your valve, simply choose the common functions and spool-section specific options you require and enter the cor respond-ing code or value into the box for the relevant item number inthe CSF.

Should you require assistance completing the CS F, pleasedo not hesitate to contact your nea rest VOAC representative,

Early consultation with VOAC saves time and moneyOur experienced engineers have in-depth knowledge of thedifferent types of hydraulic system and the ways in which theywork. They a re at your disposal to o ffer qualified advice on thebest system for the desi red combination of functions, cont rolcharacteristics and economic demands. By consulting VOAC

early in the project planning stage, you are assu red of a com-prehensive hydraulic system that will give your machine thebest possible operating and cont rol characteristics.Subject to alteration without prior notice.

The graphs and diagrams in this catalogue a re typical exam-ples only. While the contents of the catalogue a re updated con-tinually, the validity of the info rmation given should always beconfirmed. For mo re detailed info rmation, please contact VOAC.

Conversion factors1 kg = 2.2046 lb1 N = 0.22481 lbf1 bar = 14.504 psi1 l = 0.21997 UK gallon1 l = 0.26417 US gallon1 cm3 = 0.061024 in3

1 m = 3.2808 feet1 mm = 0.03937 in9/5 °C + 32 = °F


3

Contents PageGeneral description of valveGeneral description of valveGeneral description of valveGeneral description of valveGeneral description of valve ...................................................................................................................................................................................................................................................................................................................................................................................................... 4Load sensing systems (LS)Load sensing systems (LS)Load sensing systems (LS)Load sensing systems (LS)Load sensing systems (LS) ................................................................................................................................................................................................................................................................................................................................................................................................................ 5Constant-flow systems (CFC)Constant-flow systems (CFC)Constant-flow systems (CFC)Constant-flow systems (CFC)Constant-flow systems (CFC) ............................................................................................................................................................................................................................................................................................................................................................................................ 7Connecting up the systemConnecting up the systemConnecting up the systemConnecting up the systemConnecting up the system ..................................................................................................................................................................................................................................................................................................................................................................................................................... 8

A. Series connection ............................................................................................... 8B. Parallel connection ............................................................................................. 8

TTTTTechnical dataechnical dataechnical dataechnical dataechnical data ...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 9-10Environmental characteristics .............................................................................. 10

Hydraulic cirHydraulic cirHydraulic cirHydraulic cirHydraulic circuit diagram of basic functionscuit diagram of basic functionscuit diagram of basic functionscuit diagram of basic functionscuit diagram of basic functions ............................................................................................................................................................................................................................................................... 11Inlet sectionInlet sectionInlet sectionInlet sectionInlet section ......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 12

Inlet types BF, BV, A39 [9] .................................................................................... 13Tank gallery [10] .................................................................................................... 14Regulating spool [11] ............................................................................................ 14No-load signal [12] ............................................................................................... 15Pressure relief valve [15-17] ................................................................................. 15Pressure relief valve [15] ...................................................................................... 15Pressure setting [16] ............................................................................................. 15Tank connection T1 [18] ....................................................................................... 15Load-signal connection, LSI [20] ......................................................................... 15

End sectionEnd sectionEnd sectionEnd sectionEnd section .............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. 16Load-signal system [13] ....................................................................................... 16Tank connection T2 [19] ....................................................................................... 16Load-signal connection, LSU [21] ........................................................................ 16

Spool sectionSpool sectionSpool sectionSpool sectionSpool section ............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 17Connections [28] ................................................................................................... 17Spool actuators [26] .............................................................................................. 18Hand-operated spool actuators with open spool end ......................................... 18Remote controlled ON/OFF spool actuators with open spool end ..................... 19Lever bracket ........................................................................................................ 19Remote controlled proportional spool actuators with closed spool end ............ 20Choice of spool ..................................................................................................... 21Spool function [22] ................................................................................................ 21Spool designation [23] .......................................................................................... 21Area relationships (cap) [24] ................................................................................ 21Options in the spool section ................................................................................. 22Accessories in the pressure gallery [25] ............................................................. 22Pressure limiters in the service ports (port relief valves) [31] – [34] .................. 23Pressure setting [32] [34] ..................................................................................... 23

Function blocks (customized manifolds)Function blocks (customized manifolds)Function blocks (customized manifolds)Function blocks (customized manifolds)Function blocks (customized manifolds) ............................................................................................................................................................................................................................................................................................. 24LeversLeversLeversLeversLevers ...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 24Dimensional drawingsDimensional drawingsDimensional drawingsDimensional drawingsDimensional drawings ................................................................................................................................................................................................................................................................................................................................................................................................................ 25-27

[00] Refers to item numbers in Customer Specification For[00] Refers to item numbers in Customer Specification For[00] Refers to item numbers in Customer Specification For[00] Refers to item numbers in Customer Specification For[00] Refers to item numbers in Customer Specification Form.m.m.m.m.


4

The HV08 is a load sensing, pressurecompensated directional control valveintended for use in both load-sensingsystems and constant-flow systems. Thevalve, which is stackable, is designedfor many different applications in ma-chines such as trucks, cranes, loadersand excavators.

Compact system constructionThe HVO8 is of modular constructionand offers unique possibilities to inte-grate application-adapted function solu-tions into the valve to form a complete,compact system solution for the ma-chine.

Freedom in machine designThe valve can be equipped for directcontrol by means of levers, or for elec-tric, pneumatic or hydraulic remote con-trol. Combinations of direct and remotecontrol are also possible. These optionsgive great freedom to the machine de-signer, since they enable the valve to belocated ideally on the machine using thecontrol medium best suited to the appli-cation in question.

EconomyThanks to modular construction, theHV08 can be optimized for both simpleand complex functions. The possibility ofintegrating complete function solutionsinto the valve gives low overall systemcosts. The HV08 can be re-built or ex-panded at any time to meet changingdemands. Moreover, by combining func-tion-adapted solutions with load-sensingsystems, energy consumption can bekept to a minimum.

DesignThe HV08 is stackable and can be sup-plied in combinations of 1 to 6 spoolsections. It can also be supplied in com-bination with function blocks, which arespecially customized manifolds.

The valve is designed for systempressures up to 320 bar and can beequipped with port relief valves in theservice ports for pressures up to 350bar. The flow range is up to 300 l/min,depending on how the valve isequipped.

The valve is designed for use in sys-tems with fixed or variable pumps.

Essential features and benefits• Modular construction: makes the

HV08 very flexible, in that it is easy tore-build or expand the valve at anytime to meet changing needs.

• Broad system compatibility: can beused in LS, CFC, CP and CPU sys-tems, thus giving you the freedom tochoose the hydraulic system bestsuited to the machine and applicationin question.

• Good control characteristics: giveprecise control of the machine in bothlifting and lowering movements.

• Can be equipped for both multi-pumpand multi-valve systems: increasesfurther the HV08’s range of applica-tions in different types of hydraulicsystem.

• Can be flanged to specially custom-ized function manifolds: enables theintegration of even more functions(even total system solutions) into a

compact, single unit that does notrequire any extra external hoses orpipes, thus making the installationsimple, tidy and especially reliable.

• Wide range of spool actuators for ei-ther direct or remote control: enablesthe valve to be located in the mostpractical place on the machine. Therange includes both hand-operatedand remote-controlled spool actua-tors of different types, thus enablingthe best combination of economy andcontrol characteristics to be obtained.The remote control system can be ofthe electric, pneumatic or hydraulictype.

• Individual load-hold check valves ineach spool section: effectively pre-vent undesirable sinking of the load,thus improving operational safety.

• Individual port relief valves in eachservice port: enable port-specific limi-tation of maximum pressure to suitprecisely the respective functions be-ing controlled.

• Quality and precision: quality materi-als and high manufacturing precisionensure a superior product with lowinternal leakage and long service life.

• Simplicity and serviceability: an em-phasis on simple design makes theHV08 easy to service.

General


5

Basic circuit diagram for LS system

Load-sensing systems (LS)In load-sensing systems, both pressure and flow a re adaptedaccording to demand. The HV08 cont rols pump displacementby means of a load signal, so that a constant p ressure diffe ren-tial between the pump line and the signal line is obtained, i.e.the pump pressure is dete rmined by the heaviest load control-led by the valve. While some suppliers and ce rtain publica-tions refer to CFC systems (see page 7) as load sensing,VOAC reserves the LS denomination exclusively for systemsthat contain a variable pump and load-sensing valve.

Since load-sensing systems contain mo re complex cont roltechnology compa red with constant-flow and constant-pres-sure systems, the re are greater demands on the machinebuilder ’s knowledge of cont rol technolog y. The combination ofhigh efficiency and good cont rol characteristics require themain spools in the HV08 to be customized to the respectivefunctions. As in constant-flow systems, simultaneously operat-ed functions should have roughly the same pressu re demands.If not, they should be divided into separate circuits so that opti-mal efficiency may be obtained. Mechanical constructionshould be rigid, since load-sensing systems can translate vi-bration in the construction into va rying pressure demands,which can result in self-induced oscillation (hunting) in the sys-tem.

Load-signal systems can be built up in di fferent ways. TheHV08 is designed so that oil can circulate in the system withoutany oil being taken from the service po rts, with the result thatthe pump reacts quickly even in cold weathe r. Even the pumpregulators can be designed in di fferent ways. Ce rtain regula-tors consume no oil from the load-signal line, while others havea leakage restrictor that maintains a ce rtain consumption. Athird variant feeds oil into the load-signal line (a flow that mustbe drained off in a suitable way). The HV08 can be equippedwith a built-in load-signal drainage facility that drains off ap-prox. 1 l/min f rom the load-signal line, regardless of the pres-sure.

LS systems have outstanding characteristics when de-signed in the right wa y. For this reason, customers are advisedto consult VOAC for assistance with the design of the enti re LSsystem, so that its advantages may be exploited in full.

System description (variable pump)

Load sensing and pressure compensationThe pressure diffe rential regulated by the pump regulator re-sults in the flow to the heaviest load always being pressurecompensated, i.e. the flow through the service po rt is inde-pendent of variations in the load pressu re.

Functions can be pressu re compensated in two ways. Thefirst involves exploiting the e ffect of the flow fo rces on a hy-draulic p roportionally controlled (fo rce controlled) valve spool.This gives simple and reliable function, with p ressure compen-sation of both lifting and lowering movements, without the needfor extra components. The second way is to equip each spoolsection with a compensator that maintains a constant p ressuredrop over the inlet restriction. This enables even di rectly con-trolled valves to be p ressure compensated, but makes thevalve more complex. The HV08 is pressu re compensatedthough exploitation of the flow fo rces. See diagram on page 6.VOAC does, howeve r, make directional valves equipped withpressure compensators, e.g. our L and K series valves.


6

20 40 60 80 1000

100

150

200

250

50

0

Directly actuated spoolq(l/min) Flow rate in service port

Lever stroke in %

Hydraulically proportionally controlled spoolq(l/min) Flow rate in service port

Pressurecompensatedlift curve

300 bar lower150 bar50 bar

D-spool Q=250

Control characteristicsThe use of pressure-compensated spools in the HV08 helps toachieve good control characteristics.

When lowering a load at a speed higher than the availablepump flow, great demands are placed on the replenishingcharacteristics of the valve. In the HV08, these demands aremet by equipping the service ports of the valve with specialanti-cavitation valves. To further improve the replenishing ca-pabilities, a counterpressure valve can be placed in the tankoutlet of the valve. In HV08 valves with closed spool actuators(PC and EHC), the spools are pressure compensated. The in-fluence of the load on speed is therefore negligible. Whenmore than one load-lifting function is operated simultaneously,it is the heaviest load that is pressure compensated.

Constant-pressure systems (CP)The distinguishing feature of a constant-pressure system isthat the pressure is kept constant while the flow is varied ac-cording to demand.

The constant-pressure system is of simple construction. Itemploys a pump with variable displacement that is regulatedto keep the pressure constant. The pump-regulating unit issimpler than the one in a load-sensing system. The constant-pressure system has outstanding control characteristics.

With the HV08, the control characteristics in constant-pres-sure systems are equal to those in load-sensing systems.

20 40 60 80 1000

100

150

200

250

50

0

Pressurecompensatedlift curve

300 bar lower150 bar50 bar

DPC-spool Q=250

Lever stroke in %


7

System description (fixed pump)

∆p connection P – T1 Idling-unloading characteristic

Pump flow Q (l/min)

The graph above shows the pressure drop over the valve (re-gardless of the number of spool sections) when all spools arein neutral.

See page 6 for control curves. Load-sensing systems andconstant-flow systems have the same excellent control curvesthanks to the design of the bypass in the HV08 valve.

2

4

6

8

10

00 50 100 150 200 300250

Basic circuit diagram for CFC system

Constant-flow systems (CFC)A constant-flow system is a system in which the flow is con-stant at a given engine speed, while the pressu re is adaptedaccording to demand.

Two diffe rent kinds of di rectional valve can be used in con-stant-flow systems: the open-centre valve (CFO) and theclosed-centre valve (CFC). The HV08 is available in a CFC ve r-sion. (VOAC also makes CFO valves, e.g. the HV07 and seriesF and H valves.) The diffe rence between a CFO valve and aCFC valve is that, in the fo rmer, oil that is not used passesthrough the valve ’s free-flow gallery and back to tank, whereasthe CFC valve has a bypass function that drains the surplus oilback to tank. In the HV08, this is achieved in two stages for thepurpose of minimizing the no-load losses. When no functionsare operated, an idling-unloading poppet (A) opens to connectthe pump line with the tank. Thanks to the design of the bypassin the HV08, the spool sections work in the same way as inload-sensing systems, i.e. the same control and pressu re-compensation characteristics are obtained.

When more than one lifting function is operated at thesame time, the pressure is determined by the heaviest load.For this reason, simultaneously operated functions should haveroughly the same p ressure demand. If not, they should be di-vided into separate ci rcuits in o rder to minimize c ross-function-al interference and give good operating econom y. Providedthat the bulk of the pump capacity is used, constant-flow sys-tems are ve ry economical. It is the refore important to dimen-sion the pump cor rectly.

A


8

Connecting up the systemWhen a system contains mo re than one valve, it can be con-nected up in di fferent ways. A few examples ar e given belo w.

A. Series connectionThe pump is connected to valve 1. Any flow not di rected to aconsumer by valve 1 continues to valve 2. This means thatvalve 1 has priorit y, i.e. in the event of full flow demand th roughvalve 1, no flow continues to valve 2. See also [10] on page 14.

B. Parallel connectionIn parallel connection, one pump is connected to mo re thanone valve in such a way that they all function as though theywere a single valve.

KeyP = Pump connectionT1 = Tank connection T1T2 = Tank connection T2LSI = LS connection in inlet section (used only in series

connection in LS systems)LSU = LS connection in outlet section (no rmally connected

to the pump r egulator, LS)a = Connection for idling unloading signal in inlet sectionb = Connection for idling unloading signal in end section

See page 12 for description of inlet section.

Inlet type BF Inlet type BF

Inlet type BF Inlet type BV or A39

Inlet type BF Inlet type BV

Inlet type BV Inlet type BV or A39

aT1LSIP

LSU

b

T2

Spool sectionwith outlet

Spoolsection(s)

Inletsection

Series connection, CFC

Series connection, LS

Parallel connection, CFC

Parallel connection, LS


9

PressuresPump connection max. 320 bar (4600 psi)Service port max. 350 bar (5000 psi)Tank connection, static max. 15 bar (217 psi)

Flow rate (recommended)Pump connection max. 300 l/min* (79 US gpm)Return from service port max. 250 l/min (66 US gpm)* Max. recommended flow rate is dependent on choice ofspool.

Feed reducerAdjustment range 20 – 220 bar

(290 – 3190 psi)

Internal pilot pressure25, 35 or 50 bar (363, 508 or 725 psi)(applies to EHC spool actuator).

Leakage from service port over spoolFrom A or B port: max. 15 cm3/min (0.92 in3) at100 bar (1450 psi), temperature 50 °C (122 °F) andviscosity 30 mm2/s (cSt).

Technical data

Pilot-operated pressurerelief valve [15]

Take-off of idling-unloading signalin inlet [12]

Pumpconnection

Spool actuator [26]

Tank connectionT1 [18]

Tank connection T2 [19]

Service port, A-port, section 1

Service port, B-port, section 2

Spool actuator [26] Connection for hydraulicremote control (PC).Actuation: pump to serviceport A

Connection for hydraulicremote control (PC).Actuation: pump to serviceport B

Inlet section [9]

Load-signal take-offin inlet, LSI [20]

Gauge port(pump pressure)

Load-signal take-offin end section, LSU[21]

Take-off of idling-unloading signalin outlet [12]

∆p (bar) Pressure-drop curves

q (l/min)

1 Pressure drop P – A/B with double-acting spool for 250 l/min.2 Pressure drop A/B –T1 with double-acting spool for 250 l/min.3 Pressure drop A/B –T1 with motor spool for 250 l/min.

5

10

00 50 100 150 200 250

12

3

Pressure drops


10

ConnectionsAll standard signal connections are available in two versions,unless stated otherwise:

• G1/4 (BSP pipe thread) for flat seal (type Tredo) accordingto ISO 228/1

• 9/16-18 UNF-2B for O-ring seal according to SAE J1926/1

The pump, tank and service-port connections are available inthree different versions: two split-flange types and a pipe-thread version.

• 1" flange plane according to SAE J518 standard pressure,but with M10 or UNC 3/8-16 fixing screws. Thread depth inboth cases: 20 mm.

• BSP pipe-thread G1 for flat seal (type Tredo) according toISO 228/1.

WeightWeight varies somewhat depending on the configuration of thevalve. The details below are therefore approximate.

Complete valve Weight in kg Weight in lb1 spool section 24 52.92 spool sections 34 75.03 spool sections 44 97.04 spool sections 54 119.05 spool sections 64 141.16 spool sections 74 163.1

Environmental characteristicsThe valve is delivered painted with an anti-corrosion basepaint. Steel parts subject to the risk of corrosion are protectedby means of zinc-plating and yellow chromating, nitro-carburiz-ing or similar. Certain spool actuators are supplied readygreased.

The O-rings in the valve are usually of nitrile rubber. Forconstant-pressure systems, however, we recommend that A30[14] be selected to give O-rings of Viton in parting surfacesbetween the sections, since Viton withstands heat better thannitrile rubber. (Much heat is generated in constant-pressuresystems that work hard.)

TemperatureOil temperature, functional range -20 °C to + 80 °C

(-4 °F to 176 °F)Oil temperature, working range +20 °C to + 80 °C

(68 °F to 176 °F)

FiltrationFor the main circuit, filtration should be arranged so that TargetContamination Class 18/14 according to ISO 4406 is not ex-ceeded. For the pilot circuit, Target Contamination Class 18/13according to ISO 4406 must not be exceeded.

Hydraulic fluidsBest performance is obtained using mineral-based oil of highquality and cleanness in the hydraulic system. HLP hydraulicfluids (DIN 51524), automatic-gearbox oil type A and API CDengine oils can be used. Synthetic, fire-resistant and environ-mentally friendly fluids can also be used. If in doubt, pleasecontact VOAC for further information.

Viscosity, function range 15 - 5000 mm2/s (cSt)(at start-up only)

Viscosity, working range 15 - 380 mm2/s (cSt)

Technical data in this catalogue is applicable at a viscosi-ty of 30 mm 2/s (cSt) and temperature of 50 °C (122 °F).


11

Diagram shows HV08 in CFC version with two spool sections.

Hydraulic circuit diagram for basic functions

is equipped according to the description below. For otherequipment options, please see under respective functionarea [item number] further on in catalogue.

Item Code Description

1 CFC Valve configured for constant-flow system.

9 BF Inlet for fixed pump (CFC).

10 TO Open tank duct.

11 F1 Spring for 13 bar, ∆p P-LS.

12 X Inlet section equipped with idling-unloading pop-pet. In the end section, the connection for theidling-signal line is plugged and the signal lineconnected with tank.

13 LD Valve equipped with pressure-compensated load-signal drainage.

15 PLS Adjustable pilot-operated pressure relief valve(controlled by pressure in load-signal line).

16 200 Pressure relief valve set at 200 bar.

18 T1 Tank connection T1 open.

19 T2B Tank connection in end section plugged.

20 LSIB Load-signal connection in inlet plugged.

21 LSUB Load-signal connection in end section plugged.

22 DPC Section 1 equipped with double acting, hydrauli-cally remote controlled spool for one double act-ing function.

EPCB Section 2 equipped with double-acting, hydrauli-cally remote controlled spool. Absence of loadsignal (no tracer spool fitted on A-side) makesEPCB function single acting. Service port A isplugged.

The item numbers in the hydraulic circuit diagram aboveand in the columns below refer to different function areasfor which different options can be selected. The valve above

Item Code Description

23 PA Spool with code “PA” fitted.

24 0.7 Spool selected for section 1 is intended to controla hydraulic cylinder with area relationship 0.7.

25 N1 Section 1 equipped with check valve to preventundesirable sinking of load.

MR Section 2 equipped with feed reducer to limitmax. pressure.

26 PC2 Spool actuator for proportional remote control bymeans of pilot pressure.

28 8SM Service ports in split-flange version with metricfixing screws. Other connections in BSP pipethread version.

31 PA Section 1 service port A protected against over-loading and cavitation by combined port-reliefand anti-cavitation valve.

Y2 No port-relief or anti-cavitation valve in section 2,service port A.

33 PA Section 1 service port B protected against over-loading and cavitation by combined port-reliefand anti-cavitation valve.

N2 Section 2 service port B protected against cavita-tion by anti-cavitation valve.

Tracer spool No tracer spool incase of E-function

T1

18

10 15, 16 31 33 31A B A B

12

20

LSIB

25 26 25 26

P1, 9 21

LSUB

13

12

T2B

19

33

2828 2626

22, 23, 24 22, 23, 24

11

Damping restrictor for by-pass (load-up damping)


12

Inlet section

Inlet section type BF for systems with fixed pump

Inlet section type BV for systems with variable pump

The inlet section is available in two basic versions, one forpumps with fixed displacement and one for pumps with varia-ble displacement. Both contain an adjustable, pilot-operatedpressure relief valve. The inlet for fixed pumps also contains abypass unit that drains surplus oil to tank, as well as an idling-unloading valve that reduces the Pump-to-Tank pressure when

no functions are being used. The bypass unit incorporates anadjustable restrictor that is used to set the response time onreceipt of a signal.

In addition to the two basic versions of the inlet section, thereis a unit that contains no functions whatsoever.

Pump connectionTank connection T1 [18]

Pilot unit for pres-sure relief valve [15]

Idling-unloading poppet

Pump connectionTank connection T1 [18]

Open tank duct T0 [10]

Bypass unitregulating spool

Bypass spring [11]

Pilot unit for pres-sure relief valve [15]

Open tank duct T0 [10]

Pressure relief valveregulating spool

Control spring [11]

Load-updamping


13

Type of inlet section [9]In addition to the aforementioned functions, the inlet sectionscontain connections for the pump, tank and various signals. Acounterpressure nipple [10] can also be fitted in the inlet sec-tion.

BF Inlet section for systems with fixed pump (CFC).

BV Inlet section for systems with variable pump (CP, LS)

A39 Inlet section without functions.

Inlet type BV.

Inlet type A39

Adjustable pilotcontrol to maintainpressure limitation(PLS, PLB [15])

Idling-unloadingpoppet

Signal line foridling-unloadingfunction

Bypass

Adjustable restric-tor for load-updamping

Load-signal line

Inlet type BF.

Adjustable pilotcontrol to maintainpressure limitation(PPS, PPB [15])

Bypass

Load-signal lineblocked

Signal line foridling unloading

Load-signal line


14

Tank gallery [10]The tank gallery in the inlet section can be equipped with acounterpressure valve to raise the pressure in the tank galleryto improve the replenishing characteristics (see items [31] and[33]). This function is particularly important in LS systems, inwhich the return flow should not be restricted too severely. Thecounterpressure valve is located in such a way that it does notraise the no-load losses in CFC systems.

Alternatively, a plug can be fitted to separate the T1 and T2tank connections (see “Connecting up the system” on page 8).

PT Counterpressure valve in tank gallery. Tank line mustalways be connected to T1 connection [18].

SP Series connection plug – used in the first valve in se-ries connection. T1 connection [18] connected topump connection on subsequent valve. Tank connec-tion T2 must be open.

T0 Open tank duct in inlet section. Normal version.

Regulating spool (bypass) [11]In the BF type inlet section [9], the bypass function consists oftwo parts; a no-load poppet and a regulating spool. When allspools are in neutral, the no-load poppet is open, i.e. the flowpasses to tank with a low pressure drop. As soon as a spool isactuated, the no-load poppet closes and the regulating spoolcomes into force. The pressure drop over the regulating spoolis determined by the heaviest load plus the spring force of thebypass. This means that the pump pressure will always be afew bar higher than what the heaviest load requires. By select-ing a stronger spring, the pressure differential can be in-creased so that more flow can be obtained from the serviceport.

F1 Weak spring: gives pump pressure approx. 13 barhigher than load pressure. Gives nominal flow throughservice port.

F2 Strong spring: gives pump pressure approx. 19 barhigher than load pressure. Gives approx. 20% moreflow through service port than F1.

F3 Extra strong spring: gives pump pressure approx. 25bar higher than load pressure. Gives approx. 40%more flow through service port than F1.

F0 Without spring (normally not used).

PT – Counterpressure valve in tank gallery.

SP – Series-connection plug in tank gallery.

T0 – Open tank duct.


15

∆p (bar) Pressure relief characteristic

q (l/min)

No-load signal [12]When more than one valve is connected in parallel in CFC sys-tems, the idling-unloading signal must be transmitted betweenthe different valves. See “Connecting up the system” on page 8.

L No-load poppet in inlet section. Nipple for parallelconnection fitted in end section. BF inlet only [9].

X No-load poppet in inlet section. Signal line connectedwith tank in end section. BF inlet only [9]. Normal ver-sion.

A0 Signal connection in inlet open. In end section, signalline is connected with tank. BV inlet only [9]. Normalversion.

AB Signal connection in inlet plugged. In end section,signal line is connected with tank. BV inlet only [9].

LA Signal connection in inlet open. Parallel connectionnipple fitted in end section.

L – No-load poppet in inlet section. Nipple for parallel connec-tion in end section.

X - No-load poppet in inlet section. Signal line connected withtank in end section.

A0 – Signal line open in inlet section and connected with tankin end section.

AB – Signal line plugged in inlet section and connected withtank in end section.

LA – Signal line open in inlet section. Nipple for parallel con-nection fitted in end section.

300

400

350

50

100

150

200

250

00 50 100 150 200 250 300 350

Pressure relief valve [15 – 17]The pressure relief valve is pilot operated, which gives it anexcellent pressure characteristic. A small, adjustable, direct-acting pressure limiter pilot-controls the regulating spool [11].The pilot flow is taken from either the pump line or the load-signal line. In systems in which it is possible to take the pilotpressure from the load signal, this option is recommended,since the pressure limiter cuts pressure peaks that are greaterthan the spring force of the regulating spool [11], regardless ofthe pump pressure. This gives more gentle regulation.

Pressure relief valve [15]PLS Adjustable, pilot-operated pressure relief valve.

Controlled by pressure in load-signal line.

PLB Adjustable, sealed, pilot-operated pressure reliefvalve. Controlled by pressure in load-signal line.

PPS Adjustable, pilot-operated pressure relief valve.Controlled by pressure in pump line.

PPB Adjustable, sealed, pilot-operated pressure reliefvalve. Controlled by pressure in pump line.

Y1 Without pressure relief valve.

Pressure setting [16]State the pressure at which you wish the pressure relief valveto be set.

Max. 250 bar for gray-iron version of valve.

Max. 320 bar for nodular-iron version of valve.


T1 Tank connection T1 open. Normal version.

T1B Tank connection T1 plugged.

Load-signal connection LSI [20]

LSI Load-signal connection in inlet open. Only in case ofseries connection in LS systems.

LSIB Load-signal connection in inlet plugged.Normal version.


16

Load-signal system [13]The load-signal system consists of one tracer spool (load-sensing spool) per service port. The tracer spool also functionsas a shuttle valve. It copies the load pressure, and the domi-nating signal is directed to the LSU connection [21] in the endsection. See also diagram on page 8.

In the CFC version, the load signal goes to the bypass,which regulates the pressure in the pressure gallery to approx.13, 19 or 25 bar above the load-signal pressure, depending onthe choice of bypass spring - [11] page 14.

The load pressures from service ports A and B are directedto their respective tracer spools. If a single-acting spool func-tion is required (EA or EB at item [22]), one of the tracer spoolsis removed. See diagram page 11.

The system permits a certain consumption in the load-sig-nal line to the pump without affecting the load-signal level. Thispermits simpler system construction and the possibility of in-stalling logic systems in the LS circuit. In the case of drainingin the pump’s LS regulator, the system has better operatingcharacteristics in winter, with quicker response times, since theoil in the LS circuit is always warm. Moreover, the system pre-vents disruptive micro-sinking of the load at the beginning ofthe lifting phase, since the signal oil is taken from the pumpinstead of the load. Since the tracer spools are two-way, it isnecessary for the load signal to be “leaked off” continuouslyfor the pump to be able to regulate when the load-signal pres-sure falls.

LD Pressure compensated load-signal drainage (givesapprox. 1 l/min)

LB Blocked load-signal drainage.

LX Load-signal duct open to tank. Used in constant-pres-sure systems (CP/CPU).


T2 Tank connection T2 open. Normal version.

T2B Tank connection T2 plugged.

Load-signal connection LSU [21]

LSU LS connection in end section open.

LSUB LS connection in end section plugged.

End section

PC1 spool actuator [26]belonging to integratedspool section


Mounting plate

LD – Pressure compensat-ed load-signal drainage.

LB – Blocked load-signaldrainage.

LX – Load signal open totank.

End section viewed in direc-tion of inlet section.

Connection of signal foridling unloading [12]

Load signal connectionLSU [21]

T2B

LSUB

The end section on the HV08 is integrated with a spoolsection. In addition to the functions of the spool section(see under “Spool section”), the end section contains load-signal drainage and connections for the tank, idling un-loading and load signal.


17

Spool section

The HV08 is stackable and can be supplied with 1-6 spoolsections. Each spool section can be equipped individually withmany different optional functions, spools and spool actuators,so that it can be customized optimally for the application andcontrolled function.

Spool sections come in two basic versions:

• single spool section for one spool

• single spool section combined with end section.

Spool sections are available in two different materials: gray ironfor a max. pump pressure of 250 bar, or nodular iron for a max.pump pressure of 320 bar. To further assist machine builders,three different types of connection are available for the serviceports in the HV08: two split-flange options (with different fixingscrews) and a BSP pipe thread option.

Connections [28]See also page 10.

8SM Service ports with 1" split-flange connections for M10fixing screws. Other connections: G1/4.

8SU Service ports with 1" split-flange connections for3/8-16 UNC fixing screws. Other connections:9/16-18 UNF-2B.

8R Service ports with G1 threads. Other connections:G1/4.

Service port, B-port [28] Service port, A-port [28]

Tracer spool forcopying of loadpressure in serviceport B Machined control edges

Spool actuator [26]

Spool function [22]Spool designation [23]

Port relief valve,PA, port A [31]

Port relief valve,PA, port B [33]

Load-hold check valve, N1 [25]


18

Spool actuators [26]There are a number of different spool actuators for the HV08.They are divided into three groups: hand-operated, ON/OFFremote controlled and proportionally remote controlled.

Hand-operated spool actuators with open spool end

C Spring-centred spool actuator.

Steplessly operated spool actuator with spring-returnto neutral.

CB Float-position spool actuator

The CB is a special spool actuator for F-spools (seepage 21). It is steplessly operated, spring-returned toneutral from the two end positions and has a fourthposition, the float position, in which the spool islocked mechanically. The spool remains locked in thefourth position until shifted manually.

Lever bracket for spool actuators with open spoolend and facility for operation by hand

A09 All spool actuators with open spool end come with alever bracket. The bracket is fitted in such a way that,when the operator pulls the lever toward him, the con-nection pump-to-service port A is opened. With theA09 option, however, the lever bracket is fitted upsidedown, so that the connection pump-to-service port Bis opened when the operator pulls the lever towardhim. If the standard and A09 bracket options are usedon the same valve, the levers will be of differentheights. For this reason, such a combination is notrecommended.

(Please see page 24 for details of the levers themselves.)

C

C + A09

CB

CB + A09


19

ON/OFF remote controlled spool actuators withfacility for operation by hand

AC2 Pneumatically remote-controlled ON/OFF spool actua-tor.

The AC2 is a pneumatically controlled ON/OFF spoolactuator with spring centring and the possibility of lo-cal stepless control by means of a hand lever (option-al).

Control pressure: min. 4 barmax. 10 bar.

Connection thread: G1/8 or NPTF 1/8-27

ACE2 Electro-pneumatically remote-controlled ON/OFFspool actuator.

The ACE2 is an electro-pneumatically controlled ON/OFF spool actuator with spring centring and the pos-sibility of local stepless control by means of a handlever (optional).

Primary air: 4-10 barControl current: (12 VDC) min. 0.85 A

(24 VDC) min. 0.42 AVoltage tolerance: ±20%

Connection thread: G1/8 or NPTF 1/8-27

ACE2F Electro-pneumatically remote-controlled ON/OFFspool actuator.

The ACE2F is identical to the ACE2 except that it hasa common pressure gallery for primary air. The prima-ry air can be connected to either the last or the firstvalve section that is equipped with an ACE2F spoolactuator.

Connection thread: G1/8 or NPTF 1/8-27.

AC2

ACE2

ACE2/ACE2F+A09

Connection,primary air

ActuationP-B, A-T

ActuationP-A, B-T

ActuationP-B, A-T

ActuationP-B, A-T

ActuationP-A, B-T

ActuationP-A, B-T

Connection,primary air

ACE2F


20

PC1 Hydraulic proportional spool actuator.PC2

The PC1 and PC2 are hydraulically, proportionallycontrolled, spring-centred spool actuators. The PC1 isused for flows up to 100 l/min through the serviceport. For flows greater than this, the PC2 is used. ThePC1 and PC2 are best controlled by the VOAC PCL4remote control valve (see separate brochure).

PC1 PC2

Breakaway pressure:* 5 bar 5 barFinal pressure:* 15 bar 25 bar

(max. 35 bar) (max. 35 bar)

Connection thread: G1/4 or 9/16-18 UNF-2B.

PC1+ Indicates that PC1 or PC2 has been equipped withA13 adjustment screw for stepless limitation of spoolPC2+ stroke length.A13

* The breakaway pressure and breakaway current refer to thepressure/current needed for the directional valve to open theconnection “service-port to tank”.

The final pressure and final current are the lowest pressure/current needed to effect full actuation of a spool in the direc-tional valve.This data must be taken into consideration when choosing pilotvalves, since the opening pressure/current of the pilot valvemust be lower than the breakaway pressure/current of thespool actuator in order to avoid jerky starting and stopping.

Moreover, the pilot valve’s final pressure/current must behigher than the final pressure/current of the directional valve toensure that the directional valve can be fully actuated.

EHC1 Electro-hydraulic proportional spool actuator.EHC2

The EHC1 and EHC2 are electro-hydraulically, propor-tionally controlled, spring-centred spool actuators.The EHC1 is used for flows up to 100 l/min throughthe service port. For flows greater than this, the EHC2is used. The EHC1 and EHC2 are best controlled bymeans of a VOAC electric remote-control system (seeseparate brochure). The VOAC PVE102 is used as apilot valve.

EHC1 EHC2Voltage: 12 V 12 VBreakaway current:* max. 360 mA max. 360 mAFinal current:* min. 700 mA min. 1050 mAPump pressure: max. 35 bar max. 35 barTank pressure: max. 15 bar max. 15 barSolenoid (PVE102): max. 1250 mA max. 1250 mA

100% ED 100% EDCoil resistanceat +20 ºC: 7.2 ohms 7.2 ohmsInductance: 10 mH 10 mH

EHC1 EHC2Voltage: 24 V 24 VBreakaway current:* max. 220 mA max. 220 mAFinal current:* min. 400 mA min. 600 mAPump pressure: max. 35 bar max. 35 barTank pressure: max. 15 bar max. 15 barSolenoid (PVE102): max. 680 mA max. 680 mA

100% ED 100% EDCoil resistanceat +20 ºC: 24.6 ohms 24.6 ohmsInductance: 32 mH 32 mH

Connection thread: G1/4 or 9/16-18 UNF-2B.

ActuationP-B, A-T

ActuationP-A, B-TPC1

PC2

EHC1EHC2

ActuationP-B, A-T

ActuationP-A, B-T

Spool-stroke limitationP-A, B-T

Spool-stroke limitationP-A, B-T

Spool-stroke limitationP-B, A-T

Spool-stroke limitationP-B, A-T

PC1/PC2

EHC1/EHC2

Remote controlled, proportional spool actuators with closed spool end

Mechanical adjustmentof “breakaway pres-sure” P-A, B-T

Mechanical adjustmentof “breakaway pres-sure” P-B, A-T

Mechanical adjustmentof “breakaway pres-sure” P-A, B-T

Mechanical adjustmentof “breakaway pres-sure” P-B, A-T

PVE102 pilot valve


21

Choice of spool

The spool is the most important link between the actions of theoperator and the movement of the controlled function. VOACHydraulics therefore goes to great lengths to optimize spoolsfor different flows, load conditions, functions and applications.Since this is a continuous development process, new spoolsare being introduced all the time. For this reason, the manydifferent spools available are not detailed in this catalogue. Forassistance with the choice of spool therefore, please contactyour nearest VOAC representative.

Spool function [22]Spools are divided into different groups, depending on theirbasic function.

D Double-acting spool for, e.g. double-acting cylinder.Blocked in the neutral position.

EA Single-acting spool for, e.g. single-acting cylinder.Blocked in the neutral position. Service port and trac-er spool B blocked. See diagram page 11.

EB Single-acting spool for, e.g. single-acting cylinder.Blocked in the neutral position. Service port and trac-er spool A blocked. See diagram page 11.

M Double-acting spool for, e.g. hydraulic motor. Serviceports connected with tank (float position) in neutral.

F Double-acting spool with fourth position in which bothservice ports are connected with tank (float position).Blocked in neutral position.

S Double-acting spool for double-acting function. Sspools are specially designed to handle light-loadfunctions such as swing, slew, rotate, etc.

C Regenerative spool for rapid feeding of a cylinder, orfor flow saving.

In addition to division into groups according to function, spoolsare grouped according to whether the spool end is open orclosed. Spools with closed spool end are used for the PC1,PC2, EHC1 and EHC2 spool actuators and have the letters PCas a suffix to the spool designation. The following “PC-functionspools” are available: DPC, EPCA, EPCB, MPC, SPC and CPC.Other spool actuators have spools with open spool end.

Spools with closed spool end are designed in such a waythat the flow forces can be exploited to pressure-compensatethe spool, i.e. when the load pressure or pump pressurechanges, the flow to the service port remains almost unaffect-ed. See page 6 for more information.

Spool designation [23]Each spool has an imprinted letter code to facilitate identifica-tion during tuning or servicing in the field.

Area relationship (cap) [24]The area relationship, κ, for the section in question is calculat-ed by dividing the cylinder area connected to service port Bby the cylinder area connected to service port A. The spoolsfor the HV08 are reversible and are installed in the valve ac-cording to the way in which the cylinder (the consumer) is con-nected to the valve. The value in [24] therefore determines thedirection in which the spool is to be installed. When the largeside of the cylinder is connected to the A-port, the area rela-tionship is less than 1. The area relationship for a motor is 1.

F

D/S

A B

T P

EA

EB

M

C

Cylinder area, B-portk =Cylinder area, A-port


22

Options in the spool sectionsAccessories in the pressure gallery [25]The spool-section pressure gallery can be fitted with differentaccessories to give the best system construction.

O Without load-hold check valve.

N1 Load-hold check valve to prevent undesirable loadsinking. Normal version.

MR Common feed reducer for service ports A and B fittedand factory-set at the desired pressure (from 20-220bar at a flow of 10 l/min). The reduced pressure ispractically independent of variations in either the pri-mary pressure or the flow take-off. MR contains aload-hold function. MR limits the flow capacity of thespool to approx. 85% of the stated flow.

Feed reducers are used to limit the pressure from thevalve when the section’s maximum pressure is belowthat of the main pressure relief valve, e.g. in the caseof a clamping function. By using MR as a pressurelimiter, energy losses can be kept down, since MRuses a pilot flow only. The pressure setting should bechosen so that it is as close as possible to the settingof the port relief valve, but at least 20 bar lower.

PR A prioritizing function that governs the section in theevent of excessive flow take-off. It does this by limitingor stopping the flow to the spool section in which it isfitted.

Pred (bar) Feed reducers for service ports A and B

qm (l/min)

Pred = reduced pressure in service portqm = flow through service port

O - Pressure gallery open. N1 - Check valve in pressuregallery.

180

240

210

30

60

90

120

150

00 40 80 120 160

MR – Feed reducer in pres-sure gallery.

PR – Prioritizing valve in pres-sure gallery.


23

Pressure limiters in the service ports(port relief valves) [31]-[34]The service ports in the HV08 can be equipped with individualport-relief and/or anti-cavitation valves. VOAC HVP102 andHVP106 cartridge valves are used as port relief valves.

Port relief valve [31] and [33]

X2 No port relief valve fitted. Service port connected tovalve’s tank gallery.

Y2 No port-relief or anti-cavitation valve fitted. Connec-tion between service port and tank gallery blocked.

PA Combined port-relief and anti-cavitation valve HVP102or HVP106 fitted. Valve is factory-set.

N2 Anti-cavitation valve only fitted.

Pressure settings [32] + [34]Max. 280 bar for valves of gray iron (G at item [8]).Max. 350 bar for valves of nodular iron (S at item [8]).Optional standard settings:25, 32, 40, 50, 63, 80, 100, 125, 140, 160, 175, 190, 210, 230,250, 280, 300, 330 and 350 bar.

∆p (bar) Replenishing characteristic

q (l/min)

∆p (bar) Port-relief valve characteristic

q (l/min)

A

1 2

B

3 4

A B

In the diagram above, service port A is equipped with a com-bined port-relief and anti-cavitation valve PA (1) to limit the pres-sure and prevent cavitation. Service port B is fitted with an anti-cavitation valve N2 (2) to prevent cavitation.

In the diagram above, the connection between service port Aand the tank is plugged, Y2 (3). This solution is used forspools with a single-acting function and in other cases when aconnection between the service port and tank is not required.Service port B is open to tank continuously, X2 (4).

300

400

350

50

100

150

200

250

00 50 100 150 200 250 300

10

20

30

40

50

00 50 100 150 200 250


24

Function blocksFunction blocks (manifolds) can be flanged to the HV08 to en-able total system solutions to be integrated into the valve. Inaddition to the standard units available, our experienced prod-uct and system designers can tailor function blocks to meetyour needs exactly. For more information about total systemsolutions, please contact your local VOAC representative.

The example opposite shows a specially customized func-tion block mounted to a two-section valve in place of the endsection. Like most VOAC function blocks, it was constructedusing cartridge valves, i.e. only the housing is a unique com-ponent.

LeversLevers are not supplied with the valve and must be orderedseparately. The standard levers for HV08 valves are of steel,which is surface treated to give resistance to corrosion. Leverknobs are of black plastic, with a window under which a func-tion symbol can be inserted to illustrate the function of the le-ver. Levers are supplied complete with pin kits for mounting tothe directional valve.

Lever: Ordering No.M8 (Window knob) 9126 1757 01

247

27

115 44

22

Ø27 (1.26)

(9.7

2)

(1.0

6)

(0.87)

(4.53)(1.73)


25

27

43 22

91 99 130

32

110

50 77 91

41

50

8451 30

27(1

.06)

(2.0

1)

(1.1

8)

(3.31)

(1.97)

(1.9

7)

(3.0

3)

(3.5

8)

(1.6

1)

(1.0

6)

(1.6

9)

(0.8

7)

(4.3

3)

(1.2

6)

(3.5

8)

(3.9

0)

(5.1

2)

Spool stroke 9.5mm (0.37). Openspump-to-serviceport B.

Spool stroke 9.5mm (0.37). Openspump-to-serviceport A.

Dimensional drawings (spool actuators)

C

AC2ACP2

CB

ACE2

ACE2F

Spool stroke 19mm (0.75) forspool functionF [22]. Openspump-to-serv-ice port B.

Spool stroke 9.5mm (0.37). Openspump-to-serviceport A.


26

Dimensional drawings (spool actuators)

PC1PC2

EHC1EHC2

34

100

max

51 51 100

max

34

142

95 95

142

(1.3

4)

(1.3

4)

(3.9

4)

(3.9

4)

(2.0

1)

(2.0

1)

(5.59) (5.59)

(3.7

4)

(3.7

4)


27

92

39

35 46 LSU

57127

82

166

Ø13 (4x) 41 41

35 (2x) 35 (2x)

16

60

122

62

92 92

93

77

L +

52

62

1016

L

(3.6

2)

(3.2

3)

(6.5

4)

(1.54)

(1.38)(1.81)

(5.00)

(2.24)(0.51)

(1.61) (1.61)

(1.38) (1.38)(0.6

3)

(2.63)

(4.80)

(2.4

4)

(0.3

9)

(0.6

3)

(2.44)(3.62) (3.62)

(3.66)

(3.03)

(L +

2.0

5)Dimensional drawings

No. of Resultant Lsections mm (inch)

1 176 (6.93)

2 238 (9.37)

3 300 (11.81)

4 362 (14.25)5 424 (16.92)

6 486 (19.13)

Signal connection foridling unloading

Load-signal connection, LSI

Service port B,section 2

Tank connection, T1

Tank connection, T2 Signal connection foridling unloading

Pump connection, P

Service port A,section 1

20 (0.97) (LSI, idling unloading)

Load-signal connection, LSU

Parker Hannifin ABVOAC Hydraulics DivisionS-501 78 BoråsSwedenTel +4633-16 91 00Fax +4633-12 11 43

Catalogue 9129 8543-02 (GB)Catalogue 9129 8543-06 (US)Ed. 00

For further information, please contact:

Catalogoe directional control valve...

Documents

Transcript of Catalogoe directional control valve...