directional control valve l90ls

Directional ControlValve L90LSProportional, Load-Sensing andPressure Compensated

Catalogue HY17-8504/UKCatalogue HY17-8504/USMay, 2003

2 Parker Hannifin ABMobile Controls DivisionBorås, Sweden

Directional Control ValvesL90LS

Catalogue HY17-8504/UK/US

Technical Information

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

Parker reserves the right to modify products without prior no-tice.Typical curves and diagrams are used in this catalog.Even though the catalog is revised and updated continuously,there is always the possibility of errors. For more detailed infor-mation about the products, please contact Parker.

In addition to general information and basic technical data, thiscatalogue contains descriptions of the many optional functionsyou can specify for the L90LS, so that we may customize it tocontrol your machine optimally.

Each function area of the valve is given as a subheading,followed by a brief description. When different options are avail-able for a function area, the subheading is followed by an itemnumber in square brackets, e.g. PrPrPrPrPressuressuressuressuressure re re re re relief valve [16]elief valve [16]elief valve [16]elief valve [16]elief valve [16].This is followed by a series of coded options, e.g. PPPPPA1A1A1A1A1, PS PS PS PS PS, Y Y Y Y Y,together with a brief description of what each code represents.

Alternatively, one or more pressure, flow or voltage options aregiven.

On page 7 is a general circuit diagram, which shows thebasic function areas of the L90LS, as well as the item numbersthat represent them. The same item numbers are of courseused in all sub-circuit diagrams elsewhere in the catalogue.Please note that, unless stated otherwise, all sections andviews of the valves have been drawn as seen from the inlet sec-tion.

We have developed a computer program to specify the L90LSon the basis of the criteria for each individual machine function.The program facilitates optimal configuration of the valve formaximum performance in different applications. It also gener-ates documentation in the form of a detailed specification and

hydraulic circuit diagram for your valve, as well as a unique IDnumber that is stamped into the valve data plate. Your valvespecifications are then stored on our database to facilitaterapid identification in the event of service enquiries or re-order-ing.

Catalogue layout

Computer-aided valve specification

Early consultation with Parker saves time and moneyOur experienced engineers have in-depth knowledge ofdifferent types of hydraulic system and the ways in which theywork. They are at your disposal to offer expert advice on thebest system for the desired combination of machine functions,

control characteristics and economic criterie. By consultingParker early in the project planning stage, you are assured of acomprehensive hydraulic system that gives your machine thebest possible operating and control characteristics.





List of contents Page

General .......................................................................................................................... 4Technical data ............................................................................................................... 6Hydraulic circuit diagram showing basic functions of L90LS ..................................... 7Inlet section [15] ............................................................................................................ 8

Pressure relief valve [16] ......................................................................................... 9Pressure setting [17] ............................................................................................... 9Load signal system [20] ........................................................................................ 10Pump-unloading function [22] .............................................................................. 11Tank connection T1 [25] ........................................................................................ 11Pump connection P1 [26] ..................................................................................... 11

End section [30] .......................................................................................................... 12LS connection [31] ................................................................................................ 12Pump connection P2 [32] ..................................................................................... 12Counterpressure valve / tank connection T2 [33] ................................................ 13Tank connection T3 [34] ........................................................................................ 13Internal-pilot pressure supply [37] ........................................................................ 14Pilot filter [39] ........................................................................................................ 14Separate tank connection for pilot circuit [40] ..................................................... 14Activation of lever disengagement [42] ................................................................ 14

Spool sections ............................................................................................................. 15Spool actuator, enclosed variant, ECH, PC .......................................................... 15Spool actuator, open variant, type C .................................................................... 15Basic variants of spool section [47] ..................................................................... 16Spool actuators [50] .............................................................................................. 17

Directly operated, with open spool-end ......................................................... 17Spool actuators [50] contd. ............................................................................ 18ON/OFF remote-controlled, with open spool-end .......................................... 18Remote-controlled, proportional spool actuators with open spool-end ........ 18Lever brackets [51] ......................................................................................... 18Directly operated with enclosed spool-ends .................................................. 19Proportionally remote-controlled, with enclosed spool-ends......................... 19Proportionally remote-controlled, with enclosed spool-ends......................... 20Onn/off remote controlled, with enclosed spool-ends ................................... 20Connector ........................................................................................................ 20Lever bracket [51] ........................................................................................... 21Lever disengagement [52] .............................................................................. 21Pilot restrictor [55 A, B] ................................................................................... 21

Choice of spool ..................................................................................................... 22Spool function [60] .......................................................................................... 22Flow requirements [61 A, B] ........................................................................... 22Area ratios [62] ................................................................................................ 23Load characteristics [63] ................................................................................ 23Force feedback [64 A, B] ................................................................................ 23Pressure compensator / load-hold check valve [66] ..................................... 24Damping of pressure compensator [67] ........................................................ 24Spool designations [69] .................................................................................. 24Flow settings [72] ............................................................................................ 25

Feed-reducing valve [75] ...................................................................................... 25Setting of feed reduction in the A-/B-port [75A] [75B] ......................................... 25Port relief and/or anti-cavitation valves [76 A, B] ................................................. 26

System functions ......................................................................................................... 27System signal lines [80] ........................................................................................ 27Individual LS connection [81] ............................................................................... 27Two-speed function [82] ....................................................................................... 28Internal connection of service port [85] ............................................................... 28Function manifolds [90-99] ................................................................................... 28

Dimensional drawing, Spool actuators with enclosed spool end .............................. 29Dimensional drawing, Spool actuators with open spool end .................................... 30Levers for open spool-actuators ................................................................................. 31Direct lever for enclosed spool-actuators .................................................................. 31

[00] refer to position numbers in the customer specification.





The L90LS is a stackable, multi-section,load-sensing, pressure-compensated di-rectional valve for mobile machines suchas cranes, skylifts, forklift trucks, platformtrucks, excavators and harvesters. It isdesigned for working pressures of up to320 bar and a maximum pump flow of150 l/min. The valve can be given excel-lent simultaneous-operating characteris-tics, which enable several machine func-tions to be operated responsively at thesame time, regardless of the sizes of in-dividual loads.

To facilitate precise customization fordifferent applications, the L90LS is ofwholly modular construction. Each valveis therefore built to order, so that it incor-porates exactly the valve functions andvalues needed to control the given ma-chine in an optimal way.

Compact, integral systemconstructionThe total modularity of the L90LS givesunique opportunities to integrate a widerange of normally external functions intothe valve. Such functions can be com-mon or specific to individual spool-sec-tions, so that widely differing criteria forindividual machine functions can be metin just one valve. This enables compact,tailored, logical, pre-tested, service-friendly system solutions to be createdfor many different types of machine.

In situations where flow demandsvary so greatly that two separate direc-tional valves would normally be required,the L90LS can, with the aid of a specialadapter plate, be flanged to a largervalve such as the K170LS or K220LS togive a compact, unitized system solutionand optimum economy.

Wide range of spool actuatorsThe spools in the L90LS can be actuateddirectly by means of levers or remotelyby pneumatic, electro-pneumatic, hy-

draulic or electro-hydraulic remote con-trol. Some of our remote-controlled spoolactuators can be fitted with a supple-mentary direct lever to give a dual-con-trol and/or emergency facility. The widerange of actuating options gives the ma-chine designer great freedom in terms ofcontrol criteria and component location.

Customization and economyThe L90LS can be tailored optimally tocontrol either simple or complex ma-chine-functions and combinationsthereof. Its facilities for integrating total,wholly customized solutions for a widerange of applications give low systemcosts and minimal energy consumption.

Safety and serviceabilityThe design of the L90LS makes it easyfor machine manufacturers to complywith national and international safetyregulations, such as those contained inthe EC Machinery Directive. Specialsafety functions for machines such ascranes and skylifts can be integrated intothe valve in a logical and simple way.With all system functions contained in arobust, compact, pre-tested unit withminimal external pipework, overall safetyand reliability is greatly improved at thesame time as servicing and the trainingof personnel is made much easier.

Spool sections and flow ratesThe L90LS can be supplied in combina-tions of 1-12 spool sections or in combi-nation with special function manifolds fit-ted between spool sections. The maxi-mum recommended flow rate per spoolsection is 125 l/min, or 90 l/m whenequipped with a pressure compensator.

Examples of optional functionsDepending on the application and oper-ating criteria of the machine, a wide

range of common, section- or port-spe-cific optional functions can be integratedinto the L90LS. Examples include:

• a bypass function in the inlet sectionfor systems fed by fixed pumps

• a pump-unloading function thatblocks the pump inlet when activated,thus enabling an emergency-stopfunction to be incorporated into thesystem

• section-specific pressure compensa-tion

• section-specific load-hold check func-tions

• port-specific relief and anti-cavitationfunctions

• port-specific feed reduction• port-specific force-feedback functions

that enable force-sensing and alsoprovide a hydraulic ramp function

• a load-signal copying function toeliminate micro-sinking

• a built-in pilot-pressure function in theend section

• a counterpressure function that givesexceptionally good make-up charac-teristics and the possibility of unload-ing lowering movements

• section-specific two-speed functionsthat enable switching between per-formance and precision work in ma-chines such as cranes and skylifts

• automatic stopping functions for se-lected machine movements in theevent of overload or the reaching ofother pre-determined limits

• a lever-disengagement function thatimmobilizes direct levers when remotecontrol is engaged

• priority for machine functions such asbrakes and steering.

General





L90LS with levers for direct spool actuation and equipped withbypass for systems fed by pumps with fixed displacement.

L90LS with electro-hydraulic remote-controlled spool actuatorsand equipped with direct-acting pressure relief valve for sys-tems fed by LS pumps, pump-unloading function, integrated

pilot-oil supply, counterpressure function, section-specific pres-sure compensators, port-specific feed reducing valves, port-relief and anti-cavitation valves, etc.

T1

B A B A

P2B

T2B

T3B

LSPBPL LS PX

P1

P2

T3

T1B

P1

B A B A PSTPB

LSPBPL

LS

PX





PressuresPump inlet max. 320 bar* (4600 psi)Service ports max. 350 bar* (5000 psi)Tank connection max. 20 bar (290 psi)

Flow rates, recommendedPump connection max. 150 l/min (40 US gpm)Service port, with pressurecompensator max. 90** l/min (24 US gpm)Service port, without pressurecompensator max. 125** l/min (33 US gpm)Return from service port max. 150 l/min (40 US gpm)

* Stated pressures are absolute shock pressuresat 10 bar tank pressure.

** Depending on spool variant.

Feed reducing valvesSetting range 50 - 330 bar (725-4800 psi)

Internal pilot pressureFixed setting 22 or 35 bar (320 or 508 psi)

TemperatureOil temperature, function range -20 to 90 °C (-4 to 194 °F)Oil temperature, working range +20 to 90 °C (68 to 194 °F)

FiltrationFiltration must be arranged so that Target Contamination Class20/18/14 according to ISO 4406 is not exceeded. For the pilotcircuit, Target Contamination Class 18/16/13 according to ISO4406 must not be exceeded.

Hydraulic fluidsBest performance is obtained using mineral-base oil of highquality and cleanness in the hydraulic system.Hydraulic fluids of type HLP (DIN 51524), oil for automaticgearboxes Type A and engine oil type API CD can be used.

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

Viscosity, working range 15-380 mm2/s

Technical information in this catalogue is applicable at anoil viscosity of 30 mm2/s and temperature of 50 °C using ni-trile rubber seals.

ConnectionsConnection Location G-version UN-versionP1 inlet section G 3/4 1 1/16-12 UN-2BP2 end section G 1/2 7/8-14 UNF-2BT1 inlet section G 3/4 1 1/16-12 UN-2BT2,T3 end section G 3/4 1 1/16-12 UN-2BTP end section G 3/8 3/4-16 UNF-2BA, B spool section G 1/2 7/8-14 UNF-2BLS, PL inlet section G 1/4 9/16-18 UNF-2BPX inlet section G 1/4 9/16-18 UNF-2BPS end section G 1/4 9/16-18 UNF-2BPS2 end section G 1/8 7/16-20 UNF-2BPC spool section G 1/4 9/16-18 UNF-2BACP, ACE, ACEF spool section G 1/8 1/8-27 NPTFLSA/B spool section G 1/8 7/16-20 UNF-2BLSP end section G 1/4 9/16-18 UNF-2B

WeightsInlet section 5.5 kg 12.1 lbEnd section 4.2 kg 9.3 lbSpool section with spool actuator:C, B3 4.1 kg 9.0 lbACE 5.2 kg 11.5 lbCH, CHB3, CHX, PC 4.5 kg 9.9 lbPCH 4.7 kg 10.4 lbEC, EB, 5.2 kg 11.5 lbECH, ECHL, EBHL 5.4 kg 11.9 lb

Technical data

Tank connectionT1 [25]

Connection for hydraulicremote control, PC.

Pump connectionP1 [21]

Pump connectionP2 [32]


Service port connection, A-port.

Service port connection, B-port.

Pilot pressure supplyfor external use, PS.

Separate tank connec-tion for pilot circuit, TP[40]


LS connection from parallelvalve LSP [31]

LSPXPL





Hydraulic circuit diagram showing basic functions of L90LS

The item numbers in the hydraulic circuit diagram and ta-ble below refer to the valve function areas for which differ-ent options are available. The valve in the example above

is equipped according to the description below. For otherequipment alternatives, see under respective valve-functionarea [Item number] in catalogue.

ItemNo. Code Description

15 CFC Inlet with bypass for systems with fixed pump.

16 PS Pilot-operated main pressure relief valve.

20 KB Prepared for load-signal copying.

22 BEN Electrically activated pump-unloading functionthat blocks the pump and unloads the loadsignal.

25 T1B Tank connection in inlet plugged.

26 P1 Pump connection in inlet open.

31 LSPB Load-signal connection for parallel-connectedvalve plugged.

32 P2 Pump connection

33 MF Counterpressure valve with fixed setting.

34 T3 Tank connection open.

37 R Pressure reducing valve with separate safetyvalve for internal pilot pressure supply.

39 S Internal coarse filter for pilot circuit.

40 TPB Prepared for separate tank connection from pilotcircuit.

ItemNo. Code Description

47 TTT Section 1 equipped with pressure compensator,separate feed reducers for A- and B-ports, andprepared for port relief valves in both serviceports.

000 Section 2 without pressure compensator, feed re-ducer or port relief valve.

50 EC Section 1 equipped with proportional electro-hydraulic remote control.

CH Section 2 equipped for direct operation withspring centring.

60 D Sections 1 and 2 equipped with spool for double-acting function, with service ports blocked inneutral position.

66 K Pressure compensator with built-in check valvefunction.

67 0.8 Restriction of load signal to pressure compensator.

75 Pressure setting for feed reducers in A- and B-ports.

76A N2 Anti-cavitation valve in A-port.

76B Pressure setting for combined port-relief and anti-cavitation valve in B-port.

50 66 76 75 50

25

22

20

15, 16

26

T1BB A B A

PSTPB 40

47

32

39

37

33

34

31606067

P1

PL PX LSPB

T3

P2

LS





Inlet section

The inlet section comes in four basic variants; one for fixed pumps,two for systems with variable pumps and another - a simpleplate - for use when none of the inlet section’s integrated func-tions is required. Inlet sections are equipped with pump andtank connections, a connection for the load signal to LS pumpsand gauge ports for measuring the pump and load-signal pres-sures. In all basic variants, the pump connection P1 [26] andtank connection T1 [25] are open, while the other connectionsare plugged.

The variant for fixed pumps can be converted easily in the fieldto work with variable pumps, and vice versa. (CFC ↔ LS1).

Functions for maximum pressure relief, copying of the loadsignal and pump unloading (which blocks the hydraulic energysupply to the valve) can be integrated into the inlet section.

Inlet sections [15]

CFC Inlet section for systems with fixed pump. The sectionis equipped with an adjustable, pilot-operated pres-sure relief valve [16], which protects the pump and in-let side of the valve. A built-in bypass diverts excessoil directly to tank. The bypass pressure level is con-trolled by the load signal, and is approx. 10 bar abovethe actual load-signal pressure.

LS1 Inlet section for systems with LS pump. Equipped withan adjustable, pilot-operated pressure relief valve [16],which protects the pump and inlet side of the valve.

LS2 Inlet section for systems with LS pump. Equipped witha non-adjustable, direct-acting pressure relief valve[16], which protects the pump and inlet side of thevalve. The LS2 variant is normally equipped with acopy function for the load signal, KS [20].

IP Inlet plate without functions. Contains only connectionsfor pump, load signal and a gauge port for measuringtank pressure.

∆p (bar)

CFC – Inlet section for systems with fixed pump.LS1 – Inlet section for systems with LS pump.LS2 – Inlet section for systems with LS pump.IP – Inlet plate without functions.

Pump connection P1 [26] Tank connection T1 [25]

Pressure relief valve [16]

Inlet section for fixed or vari-able pump [15]

Gauge port:

Copied loadsignal LS

Pump pressure PX

Load signal PL

Pump unloading function [22]

P1

PL PX

P1

PL PX

T1

P1

PL

LS

PX

TX

P1

PL

LS1

LS2

CFC

q (l/min)CFC – Idling (no load) pressure drop over bypass. P1 –T1.

IP





Pressure relief valve [16]The inlet section is normally equipped with a pressure reliefvalve to protect the pump and valve from pressure peaks in thesystem when there are rapid changes in the load pressure.

PA1 Direct-acting pressure relief valve, PLC183, with veryfast opening sequence and good pressure characteri-stic. The interchangeable PLC cartridge is factory set.The cartridge has a make-up function, which meansthat oil is able to flow from the tank gallery to the pumpgallery in the event of negative pressure in the pumpcircuit. The valve is intended for the LS2 inlet section[15]. For setting values, please see Pressure setting[17].

PSPSPSPSPS Pilot-operated pressure relief valve with fast openingsequence and very low pressure override, which effec-tively prevents overloading of the hydraulic pump andthe machine. The valve is adjustable and is deliveredfactory-set according to the value specified. The valveis intended for the CFC and LS1 inlet sections [15].

Y Plug which can replace the pressure relief valve in theLS2 inlet section [15]. The Y-plug blocks the connec-tion between the pump and tank completely.

Pressure setting [17]

Pressure setting for PA1 [16]The PA1 direct-acting pressure relief valve is deliveredwith a fixed setting. The following standard settings areavailable:Pressure setting in bar: 63, 80, 100, 125, 140, 160,175, 190, 210, 230, 240, 250, 260, 280, 300 and 330.

Pressure setting for PS [16]The PS pilot-operated pressure relief valve is adjust-able from 50 to 320 bar. The valve can, however, bedelivered with a fixed setting according to the valuespecified.

PA1 - Direct-acting pressure relief valve.

PS - Pilot-operated pressure relief valve.

∆p (bar) Pressure relief characteristic

q (l/min)

PS - Pilot-operated pressure relief valve.





Load signal system [20]The load-signal system consists of a series of shuttle valves,one for each spool section in the directional valve. The shuttlevalves compare the load signals from all actuated spool sec-tions and transmit the signal with the highest value to the PLconnection in the inlet section. If the valve has a load-signalcopying function, the signal is transmitted to a copy spool,which makes a copy of the signal and transmits it to the LSport.

If the load-signal chain is extended to a parallel-connectedvalve via the LSP port [31], then the highest load signal fromthe parallel-connected valve is included in the comparisonsmade by the load-signal chain in the first valve.

In the case of the CFC variant of the L90LS, i.e. the variantfed by a fixed pump, the highest load signal is transmitted tothe bypass valve, which regulates the pressure in the pressuregallery to approx. 10 bar above the value of the signal.

KB Inlet section without copy spool.The load signal goes directly to the bypass in CFCsystems, or to the PL connection in LS systems.

KS Inlet section with copy spool.The load signal acts on a copy spool, which sends acopied load signal to the LS connection.

The copying system permits a certain consumptionin the load-signal line to the pumpregulator, without theload signal being influenced. This enables simpler sys-tem construction, with the possibility of installing logicsystems in the LS circuit. Thanks to drainage in thepump LS regulator, the system gives better winter op-erating characteristics with faster response, since theoil in the LS circuit is always warm. Moreover, it pre-vents the tendency for the load to sink slightly at thebeginning of the lifting phase.

Inlet sections of type LS2 [15] are normallyequipped with copy spools.

KB - Inlet section without copy spool.

KS - Inlet section with copy spool.

Load signal to bypassor pump regulator

Load signal fromspool section

Copied load signal topump regulator

Pump

Load signal fromspool section





Pump-unloading function [22]If required, the valve can be equipped with a pump-unloadingfunction in the inlet section. This enables machine manufactur-ers to equip their machines with an emergency-stop function tocomply with the EC Machinery Directive. The function can becontrolled either electrically or hydraulically.

(The inlet section is not normally machined to accommo-date the pump-unloading function.)

BB The inlet section is machined to accommodate apump-unloading function, and plugged. This permitsthe building in of a pump-unloading function at a laterdate if required.

BEN Electrically controlled pump-unloading function. Whenthe current to the electromagnet is broken, the pumpis blocked and the load signal drained to tank. In bothLS and CFC systems, this means that the pressuregallery is shut off from the pump inlet and the pump isunloaded.

BX Hydraulically controlled pump-unloading function.When an external hydraulic signal with the same pres-sure as the pump is connected to the BX port, thepump is blocked and the load signal drained to tank.In both LS and CFC systems, this means that the pres-sure gallery is shut off from the pump inlet and thepump is unloaded.Connection: G1/2 or 9/16-18 UNF-2B.

Tank connection T1 [25]

T1 Tank connection T1 is open. Normal variant.

T1B Tank connection T1 is blocked.

T1X Used together with CFC [15] and MF or MP counter-pressure functions [33] only. Tank connection T1 in theinlet section is separated from the tank galleries in thespool sections. Pump oil that is not used flows via thebypass directly to tank via T1, while returning oil fromthe actuators flows to tank via the counterpressurevalve in the end section and tank connection T3.

Pump connection P1 [26]

P1 Pump connection P1 is open. Normal variant.

P1B Pump connection P1 is plugged.

BX – Connection of signal pressure.

BB - Machined to accommodate pump-unloading function,and plugged.

Tank

Frompump

To pressure galleryLoad signal

BEN - Electrically controlled pump-unloading function.

BX - Hydraulically controlled pump-unloading function.

External connection of signalpressure from pump line





End section

End section [30]

US Standard end-section

APE170 Adapter plate for flanging L90LS to K170LS with exter-nal feedback of load signal from L90LS inlet to adapterplate (valve not supplied with this feedback).

API170 Same as APE170, except that LS signal is fed back tothe adapter plate internally via signal duct 3. This ver-sion is preferable when the signal ducts do not need tobe used. See ‘System functions’, page 27.

APE220 Same as APE170, but for flanging L90LS to K220LS.

API220 Same as API170, but for flanging L90LS to K220LS.

LS connection [31]

LSP Port for connection of LS signal from other valve open.This connection is used to receive the load signal froma parallel-connected valve.

LSPB Port for LS signal from other valve plugged.


P2 Alternative pump connection in rear face. The connec-tion can, for example, be used to feed valves locatedto the rear, or for double feeding of the valve in appli-cations where many machine functions with very highflow demands are operated simultaneously. Under cer-tain provisions, the connection can also be used insituations when feeding from the rear face is the mostsuitable option in terms of available space. When feed-ing via P2, the pump-unloading function [22] cannotbe used.

P2B Alternative pump connection plugged.

The end section can be equipped with a number of optionalfunctions to customize it optimally for the given application. Itcan, for instance, be equipped with a pressure-reducing valveto supply internal pilot-pressure for hydraulic or electro-hydrau-lic spool actuators, and a fixed counterpressure valve in the T2port.

In the basic version of the end section, all connections areplugged.

As an alternative to the standard end-section, an adapterplate can be fitted to serve as a common end-section for theL90LS and a K170LS or K220LS valve. In such cases, note thatit is the inlet of the series-K valve that should be connected tothe pump.

LSP US

LSP – Port for connection of LS signal from other valve is open.US – Standard end-section.

Counterpressure valve/tank connection T2 [33]

Separate tank connectionfor pilot circuit [40]

Pilot pressureconnection, PS

Pilot filter [39]

Internal pilot pres-sure supply [37]


LS-connection [31]


LST

LSP

T2B

T3B

LSPB

T3B

T2BLST

TP P2B





Counterpressure valve / tank connection T2 [33]

T2 Alternative tank connection T2 open.

T2B Alternative tank connection T2 plugged.

MF Counterpressure valve factory set to give 5 barcounterpressure. Tank connection T1 must be plugged(T1B) [25] and tank connection T3 [34] must be open.

If the system has a fixed pump, CFC [15], the sepa-rate tank line T1X [25] from the bypass can be used toreduce the idling (no load) losses in the system.


T3 Tank connection T3 is open.

T3B Tank connection T3 is plugged.

T2 – Without counter- MF – Factory-setpressure valve. counterpressure valve.

T

TP

LST

LSPB

T3B

T2

P2B

LST

LSPB

T3

Common copy spool forseries-K and L90LS valve

Adapter plate,AP [15]

Inlet, series-Kvalve

Section 1,series-K

Section 2,series-K

Section 2,L90LS

Simple inlet plate,IP [15], L90LS

Section 1,L90LS

External feedback of load signal(not supplied ex-factory)

Connection of tank in caseof external pilot-pressureconnection, TP [40]

Series-K valve flanged to a L90LS valve with the aid of AP plate. Load signal fed back externally.

Series-K valve flanged to a L90LS valve with the aid of AP3 plate. Load signal fed back internally.

Connection of tank in caseof external pilot-pressureconnection, TP [40]

Inlet, series-Kvalve

Simple inlet plate,IP [15], L90LS

Common copy spool for se-ries-K and L90LS valve

Adapter plate, AP3 [15] with internalfeedback of load signal from L90LSinlet

Section 1,series-K

Section 2,series-K

Internal feedbackof load signal

Section 2,L90LS

Section 1,L90LS





Internal-pilot pressure supply [37]

R Internal pilot-pressure supply is a valve function, builtinto the end section, which works as both a pressureregulator and a pressure relief valve in the pilot circuit.For safety reasons, the R-cartridge has also beenequipped with a separate safety-valve function thatprevents the maximum permissible reduced pressurefrom being exceeded. A check valve prevents pilot oilfrom leaking back to the pump, and therefore enablesthe pressure in the pilot circuit to be maintained in theevent of a temporary fall in pump pressure, e.g. duringa rapid lowering movement.Pilot pressure for external use, e.g. for delivery to

PCL4 remote control valves, can be tapped from thePS connection on the B-side of the end section. Pres-sure setting: 35 bar.

R22 Same as R, but with 22 bar pressure setting.

R43 Same as R, but with 43 bar pressure setting.

Pilot filter [39]

S Coarse filter with bypass function in the internal pilotpressure supply. The filter protects the pilot circuit fromdirt, especially during start-up of the system.

YS Adapter for connection of external filter for pilot oil.Enables the pilot circuit to be supplied with cleaner oilcompared with the rest of the system.

Separate tank connection for pilot circuit [40]

This connection is machined into the end section only when thevalve is furnished with internal pilot-pressure supply [37].

TP Separate tank connection for the pilot circuit is open.The connection to the main tank gallery of the direc-tional valve is blocked. The function is intended forsystems in which there is a risk of dynamic pressurefluctuations in the tank line, which cause fluctuations inthe pilot circuit when there is a common tank line.

TPB The end section is machined to provide a separatetank connection for the pilot circuit, and plugged. Thetank return of the pilot circuit is connected to the tankgallery of the directional valve.

Activation of lever disengagement [42]

RB The end section is machined to accommodate the le-ver disengagement function, and plugged.

REN Electrically controlled lever-disengagement for remote-controlled spool actuators equipped with supplemen-tary direct lever. When there is no current to the RENsolenoid, pilot pressure to remote hydraulic or electro-hydraulic controls is blocked. The effect is that directlevers cannot be used when remote control is engagedand vice versa.

REA Same as REN, except that pilot pressure to the remotecontrols is blocked when the REA solenoid is ener-gized.

R - internal pilot-pressure supply.S - coarse filter with bypass function.TPB - end section machined to accom-modate separate tank connection for pi-lot circuit, and plugged.

R - internal pilot-pressure supply.YS - adapter for connection of externalpilot-pressure filter.TPB - end section machined to accom-modate separate tank connection for pi-lot circuit, and plugged.

R - internal pilot-pressure supply.S - coarse filter with bypass function.TP - end section machined to accommo-date separate tank connection for pilotcircuit, and connection open.REN - lever disengagement functionthrough electrically controlled blockingof pilot pressure.

TPS

TP

LST

LSPB

T3BT2

R

S

P2B

TPBPS

TPS

TP

LST

LSPB

T3BT2

R

P2B

TPB

YSPS

TPS

TP

LST

PS

PS2REN

LSPB

T3BT2

R

SP2B

TPPSREN





Spool sectionsThe L90LS is stackable and can be supplied in combinations of1-12 spool sections. Each section can be equipped individuallywith a variety of optional functions, as well as different types of

Spool actuator, enclosed variant, type ECH

Spool actuator, enclosed variant, type PC

Spool actuator, open variant, type C

Pressure setting, feedreducing valve [75]

Flow setting [72]

Spool function [60]Spool designation [69]

Damping of pressurecompensator [67] Pressure compensator [66]

Pilot restriction [55]

Port relief and/or anti-cavitation function [76]

Flow requirement [61]

Spool actuator [50]

Load-hold check valve [66]

Spool actuator [50]

System signal line [80]

Basic variant [47]

Lever bracket [51]

spool and spool-actuator. This enables optimum customizationto the application and particular machine function in question.





Basic variants of spool section [47]Spool sections are available in different variants depending onthe choice of optional functions:

000 Not machined for pressure compensator, load-holdcheck valve, feed reducer, port-relief or anti-cavitationvalves.

V00 Section fitted with load-hold check valve, but not ma-chined for port relief valves.

T00 Section fitted with pressure compensator, but not ma-chined for port relief valves.

TA0 Section fitted with pressure compensator and feed re-duction in A-port, but not machined for port reliefvalves.

TC0 Section fitted with pressure compensator and commonfeed reduction in A- and B-ports, but not machined forport relief valves.

TT0 Section fitted with pressure compensator and indi-vidual feed reduction in A- and B-ports, but not ma-chined for port relief valves.

**T All of the section variants above are available in ver-sions that are machined for, and can be fitted with,port relief and/or anti-cavitation valves in service portsA and B. In such cases, the letter T is given in the thirdposition in the product designation, e.g. 00T, V0T, T0T,TAT, TCT and TTT. For further information, see Port re-lief and/or anti-cavitation valves [76].

V** and T** have the same machining and can be convertedeasily from one variant to another at any time. However, the ma-chining for *0*, *A*, *C* and *T* sections is different.

For further information, see also “Pressure compensator /load-hold check valve [66]” and “Feed reducing valve [75]”.

Variant **T prepared for port-relief and/or anti-cavitation valvesin service-ports A and B.Above left: section with Y-plug in A-port and combined port-relief and anti-cavitation valve in B-port.Above right: section with combined port-relief and anti-cavita-tion valves in both A and B ports.

Variant 000 (00T) Variant V00 (V0T)

Variant T00 (T0T) Variant TA0 (TAT)

Variant TC0 (TCT) Variant TT0 (TTT)

TP

LST

B A

TP

LST

B A

TP

LST

B A

TP

LST

B A

TP

LST

B A

TP

LST

B A

T

B A

T

B A





Spool actuatorsSpool actuators of both the open and enclosed type can beused on the L90LS. Open spool-actuators, in which the spool-end is exposed, are simpler and cheaper. They are intended foruse in systems where low capital cost is a priority. They can beoperated directly by means of linear levers or mechanical coor-dinate levers (joysticks), or can be connected to remote con-trols by means of wires.

With enclosed spool-actuators, the spool-ends are totallyenclosed in oil-filled caps. Enclosed spool actuators are in-tended primarily for hydraulic and electro-hydraulic remote con-trol, but can also be the preferred choice for direct control inaggressive environments.

Many different versions of spool actuator are available. De-tails can be found on pages 17-20.

Spool actuators [50]Directly operated, with open spool-end

C Spring-centred spool actuatorSteplessly operable withspring-return to neutral.

Spring force in neutral: 60 NSpring force when fully actuated: 130 N

B3 Three-position spool actuatorEquipped with 3-position mechanicaldetent that gives 3 fixed positions:neutral and fully actuated in eitherdirection. Spool remains in selectedposition and must be moveddeliberately from one positionto another.

Force needed on spool toovercome detent: approx. 160 N

FD Friction-detented spool actuatorLever remains at selected steplessposition. A force index indicateswhen the lever is in neutral.

FD

LM

LU

C

B3

FD

C

B3





Spool actuators [50] contd.ON/OFF remote-controlled, with open spool-end

ACE Electro-pneumatic spool actuator, ON/OFFSpring-centred. Can be fitted withsupplementary local lever(optional) for direct, steplessactuation of spool.

Control pressure: min. 4 barmax. 10 bar

Spring force in neutral: 95 NSpring force when spoolfully actuated: 160 NSolenoid: 12 V DC 0.85 A

24 V DC 0.42 AVoltage tolerance: ±20%

Connections: G 1/8 or NPTF 1/8-27

ACEF Electro-pneumatic spool actuator, ON/OFF

Identical to the ACE, except that ithas a common pressure gallery forprimary air. The primary air can beconnected to either the first or thelast of the adjacent spool-sectionsequipped with ACEF actuators.

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

Remote-controlled, proportional spool actuators withopen spool-end

ACP Pneumatic proportional spool-actuatorCan be fitted with supplementarylocal lever (optional) for direct,stepless actuation of spool.The ACP is best controlled bymeans of our VP04VP04VP04VP04VP04 remote-controlvalve (see separate brochure).

Breakaway pressure*: 2 barFinal pressure*: 5.5 bar

max. 10 bar

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

Lever brackets [51]

LM For spool actuators with open spool-end

LU Spool-sealing cover without lever bracket forspool actuators with open spool-end

*The breakaway pressure is the pressure needed for the direc-tional valve to open the connection “pump to service port”. Thefinal pressure is the lowest pressure needed to effect full actua-tion of a spool in the directional valve. This data must be takeninto consideration when choosing control units, since the open-ing pressure of the control unit must be lower than the breaka-way pressure of the spool actuator in order to avoid jerky start-ing and stopping. However, the control unit’s final pressuremust be higher than the final pressure of the directional valve inorder to ensure that the spools can be fully actuated.

ACE

ACEFLM

LU

ACP

D101727

D101727





Spool actuators [50] contd.

Directly operated with enclosed spool-ends

CH Spring-centred spool actuatorHas enclosed spool-ends for use inaggressive environments, and/or toenable the lever-disengagementfunction [52] to be incorporated.Steplessly operable with spring-returnto neutral.Spring force in neutral: 70 NSpring force with spool fully actuated: 140 N

CHX Spring-centred spool actuatorSame as CH, but with stronger springsto compensate for friction in externallinkage arms etc.Spring force in neutral: 85 NSpring force with spool fully actuated: 250 N

CHB3 Three-position spool actuatorEquipped with 3-position mechanicaldetent that gives 3 fixed positions:neutral and fully actuated in eitherdirection. Spool remains in selectedposition and must be moved deliberatelyfrom one position to another.Force needed on spool toovercome detent: approx. 160 N

Proportionally remote-controlled, with enclosedspool-ends

PC Hydraulic spool-actuator

PCH Hydraulic spool-actuator with facility for supple-mentary local lever for direct control

The PC and PCH are proportional, hydraulically con-trolled spool actuators with spring-centring to neutral.They are intended to be controlled by the PCL4PCL4PCL4PCL4PCL4 re-mote-control valve. When determining a suitable con-trol pressure for the PCL4, bear in mind that its breaka-way pressure should be approx. 1 bar lower than thatof the directional valve in order to ensure gentle start-ing and stopping. The pilot pressure for the PCL4 canbe tapped from the internal pilot-pressure supply in theend section of the directional valve, via the PS connec-tion.

Control pressure, breakaway*: 5.5 barControl pressure, final*: 15.0 barPermissible pressure in pilot cap: max. 35 bar

Connections: G ¼ or 9/16-18 UNF

* See page 18.

See also separate catalogue for PCL4.

CH, CHX CH, CHXCHB3

PC

PCH

PC, PCH

CH, CHX

PC

PCH

CHB3

Stroke lengthlimitationP-B, A-T Qset B

Stroke lengthlimitationP-A, B-T Qset A



Stroke lengthlimitationP-A, B-T Qset A Control signal

P-A, B-T

Stroke lengthlimitationP-B, A-T

Control signalP-B, A-T





Spool actuators [50] contd.

Proportionally remote-controlled, with enclosedspool-ends

EC Electro-hydraulic spool actuator

ECH Electro-hydraulic spool actuator with facility forsupplementary local lever for direct controlThe EC and ECH are proportional, electro-hydrauli-cally controlled spool actuators with spring centeringto neutral. They are intended to be controlled remotelyby the IQAN or EHC35 control systems. Pilot-pressureoil for the PVC25 converter-valves is led to the spoolactuators through internal ducts in the directionalvalve. This means that only the electric cables fromthe control system to the converter valve need to beconnected externally. The converter valve is equippedwith manual override.

The ECH can be operated directly and steplessly bya supplementary local lever (optional).Spring force in neutral 60 NSpring force with spool fully actuated 350 NControl current for PVC25, 12 V

Breakaway* min. 550 mAFully actuated max. 980 mA

Control current for PVC25, 24VBreakaway* min. 260 mAFully actuated max. 510 mA

Measuring connections: G1/4 or 9/16-18 UNF

ECHL Same as ECH, but with weaker centering spring.Suitable for use, e. g. when spool actuator ismainly intended to be operated directly.Spring force in neutral 85 NSpring force with spool fully actuated 250 NControl current for PVC25, 12 V

Breakaway* min. 550 mAFully actuated max. 820 mA

Control current for PVC25, 24VBreakaway* min. 260 mAFully actuated max. 440 mA

Other data as for ECH above.

Onn/off remote controlled, with enclosedspool-ends

EB Electro-hydraulic spool actuator

EBHL Electro-hydraulic spool actuator with facility forsupplementary local lever for direct controlThe EB and EBHL are electro-hydraulically controlled on-off spool actuators with spring centering to neutral.They are intended to be controlled remotely by meansof on-off signals. Pilot-pressure oil for the QDC25 con-verter-valves is led to the spool actuators through inter-nal ducts in the directional valve. This means that onlythe electric cables from the control system to the sole-noid valve need to be connected externally. The con-verter valve is equipped with manual override.

The EBHL can be operated steplessly by hand lever.Spring force in neutral 85 NSpring force with spool fully actuated 250 NControl current for QDC25, 12 V 1300 mAControl current for QDC25, 24V 650 mA

ConnectorAMP Junior-Timer type C, 963040-3Bosch 1 928 402 404

*The breakaway current refers to the current needed for the di-rectional valve to open the connection “pump to service port”.The final current is the lowest current needed to effect full ac-tuation of a spool in the directional valve. This data must betaken into consideration when choosing control units, since theopening current of the control unit must be lower than thebreakaway current of the spool actuator in order to avoid jerkystarting and stopping. However, the control unit’s final currentmust be higher than the final current of the directional valve inorder to ensure that the spools can be fully actuated.

EC, EB

ECH, ECHL,EBHL

EC,EB,ECH,ECHLEBHL

EC, EB

ECH, ECHL,EBHL




ActuationP-A, B-T

ActuationP-B, A-T

Manualoverride





Lever bracket [51]

In addition to the normal lever-attachment angle, L1, the leverbracket is available in 8 other angles, designated L0 to L8 (seefigure opposite). In the L4 variant, for instance, the lever ismounted parallel with the spool.

L1 Standard lever-bracket for directly operated spool ac-tuators with enclosed spool-ends, e.g. CH, and for re-mote-controlled spool actuators that have facility forsupplementary local lever for direct control, e.g. ECH.

Lever disengagement [52]All spool actuators with enclosed spool-ends (both directly op-erated ones and the remote-controlled ones that have a supple-mentary local lever for direct control) can be furnished with afunction that disengages the local levers when pilot pressure isconnected to remote levers. The function requires the end sec-tion to be equipped with the REN or REA [42] electrically con-trolled pilot-pressure-blocking function. (In the case of the PCHspool actuator, pilot pressure for the PCL4 remote-control valveshould be taken from the PS2 connection on the A-side of theend section, which gives pilot oil only when the local lever isdisengaged.)

LR Local lever for direct control disengaged when pilot-pressure signal is received from REN or REA function.

Pilot restrictor [55 A, B]To give gentle control characteristics, remote-controlled spoolactuators with enclosed spool-ends are fitted with pilotrestrictors, which can be chosen individually for each serviceport. The restrictor gives a kind of ramp function.

/ Without pilot restrictor

0.8 0.8 mm pilot restrictor







Lever brackets L can be given different attachment angles.

A B

L * = P–A B–T

0

1

2

3

4

5

6

7

8

20°

20°

20°

20°

20°

20°

20°

20°

Schematic illustration of lever disengagement.

Pilot restrictor

B

A

Pilot pressure





Choice of spoolThe spool is the most important link between the operator’s ac-tuation of a control lever and the behaviour of the correspond-ing machine function. The designs of our spools are thereforecustomized to meet the operating criteria of each individual ma-chine function as accurately as possible. Spools are designedwith the aid of a computerized specification system, whichtakes all factors into account.

Spool function [60]There are many spool variants: D, EA, EB, M, CA, Dm, Da andDb, which are customized for different flows, load conditionsand actuator area ratios. The spools are also available with dif-ferent degrees of force feedback from the A- and/or B-side.

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 B blocked.

EB Single-acting spool for, e.g. single-acting cylinder.Blocked in the neutral position. Service port A blocked.

M Double-acting spool for, e.g. hydraulic motor. Floatposition function in neutral position.

CA Regenerative spool for rapid feeding of cylinder via theA-port. The large side of the cylinder is connected tothe A-port.

Dm Double-acting spool with drainage A to T and B to T,which prevents pressure build-up in the neutral posi-tion. The spool is used as a double-acting spool incombination with, e.g. an overcentre valve.

Da Double-acting spool with drainage A to T, whichprevents pressure build-up in the A-port in the neutralposition. The spool is used as a double-acting spool incombination with, e.g. an overcentre valve.

Db Double-acting spool with drainage B to T, whichprevents pressure build-up in the B-port in the neutralposition. The spool is used as a double spool in com-bination with, e.g. an over-centre valve.

Flow requirements [61 A, B]There is a wide range of computer-optimized spool designs forthe L90LS with nominal flows of up to 90 l/min per spool-sectionwhen the sections are equipped with individual pressure-com-pensators.

Without individual pressure-compensators, flows up to 125l/min per spool section are obtainable, depending on the ad-justed differential between the load-signal pressure and thepump pressure.

On the basis of the desired flows to the A and B ports en-tered in the ordering documentation, our computerized valve-specification system selects a spool to give at least the speci-fied flow, at the same time taking all other parameters into ac-count.

The maximum flow is then set by limiting the spool stroke bymeans of adjustment screws on the spool actuators or, in thecase of electro-hydraulic remote control, by tuning the electron-ics.

See “Flow settings [72]” for details on factory-set maximumflows.

Spool symbols

Dm

Da

CA

M

EB

EA

D

B A

Db

P T

q (l/min) Flow rate in motor connection

Spool stroke (mm)

Typical curves showing flow as a function of spool stroke.





Area ratios [62]The area ratio for a spool section is calculated by dividing thecylinder area that is connected to the B-port by the area con-nected to the A-port. When the large side of the cylinder is con-nected to the A-port, the area ratio is less than 1. The area ratiofor a motor is 1.

LAB - Lift load can change between the A- and B-port.

Load characteristics [63]The characteristics of the lift load can be specified accordingto five typical cases. This information is entered so that thespool can be be customized optimally for the intended applica-tion.

LAB Lift load can alternate between A-port and B-port.

LA Lift load normally on A-port only.

LB Lift load normally on B-port only.

LN No or low lift-load on A- and B-ports.

S Slewing function.

Force feedback [64 A, B]The L90LS can be furnished with a force-feedback function togive operators of the LS system the same positive sense offorce-control obtained with constant-flow (CFO) systems. Thismakes it easier for the operator to avoid damaging the machinein applications such as digging, since he is able to sense in-creasing resistance or outright obstacles to the movement of amachine function.

Force feedback also gives a kind of ramp function that re-sults in more gentle transition between rapid changes in thespeed of a machine movement. This in turn has a stabilizingeffect on the hydraulic system and results in smoother opera-tion of the machine. Both characteristics are important, espe-cially for functions like slewing movements. In addition to in-creasing the efficiency of the machine, they also minimize wear.

The A and B ports individually can be given any one ofthree different levels of force feedback. The higher the level,the greater the reduction in speed for a given lever stroke asresistance rises. This means that the operator must move thelever further if he wishes to maintain the same speed of move-ment with rising resistance.

/ No force feedback

FN Normal level of force feedback

FH High level of force feedback

FL Low level of force feedback

The force feedback function is not available for directly oper-ated valves.

A B

P T

F

A B

P T

F

A B

P T

F

LA - Lift load normally on A-port only.

LB - Lift load normally on B-port only.

Flow rate (%) Force feedback

Lever stroke (%)

Lightload

Heavyload





Pressure compensator / load-hold check valve [66]When there are demands for very good simultaneous-operatingcharacteristics or intensive, multi-section operability and re-sponsiveness, individual spool-sections in the L90LS can beequipped with integral pressure-compensators. Sections soequipped are not then influenced by other simultaneously-oper-ated machine functions, regardless of the variations in loads,provided there is sufficient pump capacity.

Responding to the instantaneous value of the load signal,the pressure compensator regulates continuously the flowthrough the spool to maintain a constant pressure-differentialbetween the pump and service-port sides of the spool. This re-sults in a constant flow to the consumer for a given lever stroke,regardless of the load pressure or any activity in other spoolsections.

The standard variant of the pressure compensator is desig-nated K. Three other variants, designated KL, KH and KX,which give 85, 120 and 150 % of the standard flow respectively,are also available. They are intended to enable furthercustomization of the spool section to suit the flow requirementsof the actuator.

All Parker pressure compensators are fast and responsive,and come with an integrated load-hold check-valve function. Ifnecessary, spool sections with pressure compensators can alsobe equipped with feed-reducing valves in the service ports toregulate the delivery pressure to the consumer to the desiredlevel.

(V** and T** spool-sections [47] have the same machiningand can be converted easily to accommodate feed-reducingand port-relief valves.)

/ Section not machined for pressure compensator orload-hold check valve.

K Standard pressure compensator.

KL Compensator that gives 85% of specified spool’snominal flow.

KH Compensator that gives 120% of specified spool’snominal flow.

KX Compensator that gives 150% of specified spool’snominal flow.

N Section equipped with load-hold check valve.

X Section machined for pressure compensator or load-hold check valve, and plugged.

Damping of pressure compensator [67]The LS restrictor affects the response of the pressure compen-sator, and is normally chosen at 0.8 mm.

/ No LS restrictor for compensator.

0.6 Alternative LS restrictor for compensator.

0.8 Recommended LS restrictor for compensator.

1.0 Alternative LS restrictor for compensator.

Spool designations [69]To facilitate optimal customization to meet the criteria of eachindividual machine function, the choice of spools is made withthe aid of our computerized specification program. The infor-mation entered at items 60-66 forms part of the basis for thechoice of spool.

Load pressure (bar)

Load-independent flow with pressure compensator.

q (l/min) Flow rate curves





Flow settings [72]The strokes of spools controlled by enclosed spool-actuatorscan be arrested to limit the maximum flow to service ports Aand B.

Qset The valve is supplied with factory-set maximum flowsto the spool section. The settings agree with the speci-fied flow-requirements to the A and B ports [61 A, B].

QsetA The valve is supplied with factory-set maximum flow tothe spool section. The setting agrees with the specifiedflow-requirement to the A port [61 A].

QsetB The valve is supplied with factory-set maximum flow tothe spool section. The setting agrees with the specifiedflow-requirement to the B port [61 B].

When setting the flow rates for spool sections not equippedwith pressure compensators in systems fed by LS pumps, thesettings are made with a ∆p of 15 bar between the pump pres-sure at the PX port and the load signal at the PL port at full flowtake-off. (For flow setting with PC spool-actuators, please seepage 19.)

Limiting the maximum flow over the spool by means of me-chanical stroke-length limitation of the spool stroke.

Setting B-port

Setting A-port

Feed-reducing valve [75]The L90LS with sections designated *A*, *C* or *T* at item [47]is equipped with feed-reducing valves.

Sections designated *A* have feed reduction in the A-port;those designated *C* have common feed reduction for the A-and B-ports; those designated *T* have individually adjustablefeed reduction for the A-port and B-port.

Feed reduction is used for system functions that require alower maximum pressure compared with the normal workingpressure of the system. The feed-reducing valve, which is step-lessly adjustable from 50 to 320 bar, reduces the delivery pres-sure in the service port to the pre-set level.

Through the use of feed-reducing valves, the delivery pres-sure can be limited without consuming any more than a pilotflow (<2 l/min).

For feed reduction to be installed, the section must beequipped with a pressure compensator. Since the feed-reduc-ing valve is a 2-way valve, pressure shocks that arise after thefeed-reducing valve must be limited with the aid of a port reliefvalve. The pressure setting on the port relief valve should be asclose as possible to the setting on the feed-reducing valve,although at least 10 bar higher.

Setting of feed reduction in the A-port [75A]Setting values for the A-port are from 50 to 300 bar.

Setting of feed reduction in the B-port [75B]Setting values for the B-port are from 50 to 300 bar.

qm (l/min) Reduction characteristics

Pred (bar)

Pred = reduced pressureqm = flow rate in service port





Port relief and/or anti-cavitation valves [76 A, B]In spool sections designated **T [47], the PLC053 can be usedas a combined port-relief and anti-cavitation valve in the serviceports to protect the valve and consumer from high system pres-sure and pressure surges.

The PLC053 is a direct-acting pressure relief valve with avery fast opening sequence and good pressure characteristic.The interchangeable PLC cartridge is factory set. The make-upfunction enables oil to flow from the tank gallery to the service-port side in the event of negative pressure in the service ports,in order to prevent cavitation.

/ Section not machined for port relief valves.

X2 Section machined for port relief valve. Service portopen to tank.

Y2 Section machined for port relief valve. Connection A/Bto tank blocked with plug.

N2 A/B side of section equipped with anti-cavitation valve.

50-350 Standard pressure settings (in bar) for port relief valvesin A- or B-ports:50, 63, 80, 100, 125, 140, 160, 175, 190, 210, 230, 250,260, 280, 300, 320 and 350.

Circuit diagram for PLC053 pressure relief valve.

∆p (bar) Pressure relief characteristic

q (l/min)

∆p (bar) Make-up characteristics

q (l/min)





System functionsThe L90LS can be equipped with integrated functions to createcomplete system solutions. The load signal from any serviceport or spool section can be connected with signal ducts andutilized to stop or limit the pressure to individual machine func-tions.

In cranes, this auxiliary controlling concept is implementedwith the aid of the M11 function manifold [90]. Another exampleof how the load-signal ducts can be exploited is in the controlof thrust pressure to rock drills, according to the instantaneousrotational torque (rotation-pressure controlled thrust).

System signal lines [80]

SF Valve section equipped with 3 signal lines that can beconnected internally to individual load signals [81], aswell as signal line for activation of two-speed function[82] and signal line for disengagement of direct levers[52]. (Lever disengagement not applicable to C, B3 orACE spool actuators [50]).

Individual LS connection [81]

/ No LS connection to signal lines. No possibility ofexternal connection either.

A1B Load signal from port A connected to duct 1.

A1B2 Load signal from port A connected to duct 1.Load signal from port B connected to duct 2.


A2B Load signal from port A connected to duct 2.

A2B2 Load signal from both ports A and B connected toduct 2.


AB No connection between load signal and signal ducts.

AB2 Load signal from port B connected to duct 2.

AB3 Load signal from port B connected to duct 3.

The load signal from more than one section can be connectedto the same duct. A check valve in each section prevents back-ward transmission of the load signal from the ducts into indi-vidual sections.

In addition to connection with the signal ducts, the load sig-nal is also available for external connection at the base of thevalve.

SF – System signal line

B A

LSB LSA

321

TP

LST

LS

A1B3 A2B

Two speed

Lever disengage line

Signal lines

LSB LSA LSB LSA

LSB LSA LSB LSA

A2B2 AB

AB2 A1B

LSB LSA LSB LSA

LSB LSA LSB LSA LSB LSA

A1B2 A2B3 AB3





Two-speed function [82]Any number of spool sections in the L90LS can be furnishedwith a two-speed function to enable switching between per-formance and precision work with machines such as cranesand skylifts.

The two-speed function is activated with the aid of the M11function manifold [90]. Activation reduces the flow to the con-sumer as indicated below:

QR2 Flow to consumer reduced to 20% of normal flow.




N.B.When a spool section is equipped with a two-speed function,the pressure compensator in the section does not have aload-hold check valve function. For this reason, overcentrevalves are required for the controlled actuator.

Internal connection of service port [85]Thanks to the internal service-port connections, system solu-tions employing function manifolds that require the service portto be used by the manifold can be integrated without the needfor external piping.

M Gives internal service-port connection downstream ofthe spool section.

A013 Gives internal service-port connection both down-stream and upstream of the spool section.

Function manifolds [90-99]The L90LS can be equipped with function manifolds that enablecomplete system solutions to be integrated into the valve.

Standard function manifolds are available for overload pro-tection, two-speed function, float position, priority for steeringand brakes, etc. In addition to the standard units, we custom-build function manifolds to meet special system criteria. Pleasecontact Parker for further information.

q (%) Flow

Lever stroke (%)

Diagram shows curves for:Normal flow.Flow with QR4 activated.Flow with QR2 activated.

Sectional manifold with internal connection of service ports todownstream function manifold.

A B

M

Normal

QR4

QR2





Dimensional drawingSpool actuators with enclosed spool end

L

CHCHX

PC

ECHECHLEBHL

67,5 (2.66)

87 (3.43)

(0.9

3)

23,5

41 (

1.61

)

61,4

(2.

42)

40 (

1.57

)40

(1.

57)

(0.4

7) 12

(1.50)38

(1.26)32

(0.94)24

94 (

3.70

)

53 (

2.09

)43

(1.

69)

35 (

1.38

)

max.160 (6.30) 179 (7.05)54 (2.13) 125 (4.92)45 (1.77) 45 (1.77)

40,5 (1.59)

36 (1.42)(0.12)

3

(0.12) 3

(1.75) 44,5

max. 115 (4.53) max. 160 (6.30)

45 (1.77)

90 (3.54)

45 (1.77)11,5 (0.45)

(1.0

6)27

129,

5 (5

.10)

157,

5 (6

.20)

No. of L L L with inlet plate IP [15]sections mm inch mm inch

1 169 6.65 144 5.672 209 8.23 184 7.243 249 9.80 224 8.824 289 11.38 264 10.395 329 12.95 304 11.976 369 14.53 344 13.547 409 16.10 384 15.128 449 17.68 424 16.699 489 19.25 464 18.27

10 529 20.83 504 19.8411 569 22.40 544 21.4212 609 23.98 584 22.99

Connection threads, see page 6.

(inch)





(0.45)11,5

45 (1.77)90 (3.54)

57 (

2.24

)

(1.0

6)27

129,

5 (5

.10)

165,

2 (6

.50)

67,5 (2.66)87 (3.43) (0

.93)

23

,541

(1.

61)

152,5 (6.00)

68 (2.68)(0.14) 3,5(0.35) 9

52,5 (2.07)

35 (

1.38

)

(1.38)35 1,5 (0.06)

43 (1.69)(0.31)

8 63 (2.48)

(1.50)38

61,4

(2.

42)

40 (

1.57

)

(1.26)32

(0.94)24

40 (

1.57

)(0

.47)

12L

CB3

CB3

ACE

Dimensional drawingSpool actuators with open spool end (inch)

No. of L L L with inlet plate IP [15]sections mm inch mm inch

1 169 6.65 144 5.672 209 8.23 184 7.243 249 9.80 224 8.824 289 11.38 264 10.395 329 12.95 304 11.976 369 14.53 344 13.547 409 16.10 384 15.128 449 17.68 424 16.699 489 19.25 464 18.27

10 529 20.83 504 19.8411 569 22.40 544 21.4212 609 23.98 584 22.99

Connection threads, see page 6.





Direct levers

Levers for open spool-actuatorsLevers M7 and M71 are made of steel with an anti-rust surfacetreatment, and fitted with a knob of black plastic. The knob onthe M71 lever has a top window for the insertion of a symbol.The lever kits are delivered complete with pin sets for mountingto the valve.

Direct lever for enclosed spool-actuatorsLever for directly operated spool-actuators with enclosedspool-end, and for remote controlled spool-actuators that havea facility for a supplementary local lever for direct control.

The ML1 lever is made of steel and has an anti-rust surfacetreatment. The lever knob is of black plastic and has a top win-dow for the insertion of a symbol. The lever kit consists of aknob, the lever shaft and a lock nut.

Ordering number Designation9122 1780-08 M79122 1780-11 M718234 9390-01 ML1

Lever M7 Lever M71

Lever ML1

(0.98)25∅

172

(6.7

7)

22

(0.8

7)

46 (1.81)

(1.06)

27∅

207

(8.1

5)

22

(0.8

7)

53 (2.09)

22(0.87)

21(0

.83)

165

(6.5

0)

(inch)

For further information, please contact:

Parker Hannifin ABMobile Controls DivisionSE-501 78 BoråsSwedenTel +4633 16 91 00Fax +4633 12 11 43www.parker.com

Catalogue HY17-8504/UKCatalogue HY17-8504/USEd. 0503

directional control valve l90ls

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