CONTROL FOCUSED TECHNOLOGY DRIVEN SCX120. SSL-1001 Rev. 4/11 Supercedes Rev. 3/11

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1 CONTROL FOCUSED TECHNOLOGY DRIVEN SCX120 SSL-1001 Rev. 4/11 Supercedes Rev. 3/11

2 Benefits/Features of SCX120 Improved efficiency means more work with less fuel Designed to minimize pressure drops High flow / low pressure drop capability in a compact package Dual tank rails that connect in each section Increased productivity by improving vehicle controllability Multi-function flow sharing, even when flow demand exceeds flow supply Pressure compensation provides consistent flow rates, regardless of load pressure SCX120 Applications Earthmoving Equipment Precise metering capabilities Simplified hydraulic system with features integrated into the main control valve Manual, hydraulic pilot operated, electrohydraulic, pneumatic control options Tractor Loader Backhoes Low leakage capabilities Works with fixed displacement or variable displacement PCLS pumps Optional priority inlet for steering or other priority functions Multiple outlet options including integrated pressure reducing valve for supplying pilot pressure to internal EH Crawlers solenoids and to external pilot control circuits Integrated on-off solenoid to control pilot pressure supply for safety cut-out Optional dual hydraulic pilot and electrohydraulic control Ability to integrate electrohydraulic side shift clamp valve or ISO to Excavators SAE pattern select controls for tractor loader backhoes Optional LMI circuitry for cranes Manual levers available with E-H actuation Wheel Loaders Low cost of ownership by utilizing a robust cost effective design Cost effective electrohydraulic sections have EH solenoids installed directly into the spool housing no bolt-on blocks or remote manifolds required High pressure ratings for NFPA or ISO standards Material/Personnel Handling Equipment Universal spools can be used in any type of spool section No load sense shuttles required, simplifying valve assembly and service Integrated filter screens on electrohydraulic proportional pressure reducing valves and load sense relief valves Telehandlers Complete Valve Family SCX120 is part of the SCX Platform which satisfies applications from lpm. SCX is available in three sizes: SCX120, SCX180 and SCX300. Aerial Work Platforms

3 SCX TAB L E OF C ON T E N T S SCX120 Cut Aways Technical Description, Product Features & Benefits Standard SCX120 Spools Standard Spool Flow Rates Standard Spool Pressure Drops (Inlet to Work Port) and Compensator Performance Standard Spool Pressure Drops (Work Port to Outlet) Inlet Section Assembly Options Spool Section Assembly Options Outlet Section Assembly Options Relief Valves, End Mechanisms and Kits HUSCO Overview HUSCO Worldwide Notes Appendix 1 Appendix Open Center versus Closed Center Post-Compensated versus Pre-Compensated

4 SCX120 CUTAWAYS INLET SELECTION CUTAWAY Load Sense Relief Valve Cavity Top Outlet Port Top Inlet Port Main Relief Valve Cavity Sump Port A Work Port Electrohydraulic Proportional Pressure Reducing Valve Sump Passage Pilot Pressure Supply Passage Inlet Gauge Port Optional End Inlet Port Load Sense Port Optional End Outlet Port ELECTROHYDRAULIC SPOOL SECTION CUTAWAY B Work Port Auxiliary Port Universal Spool Design Supply Passage Tank Passage Compensator Spool Load Hold Check Low Pressure or Tank Pressure Load Sense Passage Auxiliary Pump Passage (LS Feed) OUTLET SECTION CUTAWAY Pilot Pressure Supply Plot Sump Port 3 Optional Inlet Port Optional Load Sense Port Optional Outlet Port Pressure Reducing Valve Cavity

5 SCX120 TECHNICAL DESCRIPTION The SCX120 is a closed-center, load-sensing, sectional control valve with post-pressure compensation that offers a wide range of control options and flexibility. The SCX120 can be used with fixed displacement pumps or with pressure-compensated, loadsensing variable displacement pumps and can be configured with one to ten working sections. The load sense (LS) pressure in an SCX120 valve is generated by the compensator spool using the HUSCO patented IsoComp method to copy the LS signal using oil supplied by the pump instead of stealing oil from the function. Using pump oil to generate the LS signal prevents function droop at the start of metering when a function is selected. When multiple functions are selected, the SCX120 will automatically resolve the highest function load pressure, which is then transmitted to the pump or inlet unloader (bypass compensator). This design eliminates the need for shuttles between sections, simplifying the assembly of the valve and offers excellent flow sharing capability (the valve will maintain the ratio of flows to each function, even when flow demand exceeds flow supply). Each SCX120 valve comes with a load sense relief valve (LSRV) with an integrated pressure compensated drain function. The LS drain ensures that LS pressure drains to tank once all spools are returned to the neutral position. Each section assembly has a built-in pilot pressure supply rail and a sump rail on each side of the valve for use with electrohydraulic (EH) proportional pressure reducing valves (EPRVs). It is recommended that the sump port be plumbed directly to tank to minimize any back pressure that may affect electrohydraulic solenoid valves (a maximum sump pressure of 7 bar (100 psi) is recommended). Work port pressure limiting is accomplished by using the optional auxiliary relief valves. Each working section comes standard with auxiliary relief valve cavities machined for both work ports. See appendix page 1 for a comparison of closed center to open center valve systems. See appendix page 2 for a comparison of post-compensated to pre-compensated valve systems. SCX120 PRODUCT BENEFITS & FEATURES Excellent multi-function flow sharing with post-pressure compensation High flow, low pressure drop capability Compact size Dedicated electrohydraulic (EH) section Lever option for EH and pilot operated sections Universal spools can be used in manual, pilot operated or EH sections Stroke limiter option Allows for reduced flow from a given spool Manual override adjustment screw option Allows a spool to be shifted in a dead-engine situation 4

6 STANDARD SCX120 SPOOLS (INTERCHANGEABLE BETWEEN MANUAL, PILOT OPERATED AND ELECTROHYDRAULICALLY OPERATED SECTION ASSEMBLIES) The SCX120 3-position spool is interchangeable between manual, pilot operated and electrohydraulically operated section assemblies. Each spool is threaded at both ends, allowing any spool to be a left-handed or right-handed spool. Spool Flow Rate STANDARD SCX120 3-POSITION SPOOLS Flow rates are based on a 15 bar (215 psi) pump to LS differential pressure. Each spool is designed for the same flow rates for both work ports. Cylinder Spool Part Number Restricted Motor Spool Part Number 5 lpm (1gpm) SCX12-S0001 SCX12-S0008 SCX12-S lpm (4 gpm) SCX12-S0002 SCX12-S0009 SCX12-S lpm (8 gpm) SCX12-S0003 SCX12-S0010 SCX12-S lpm (13 gpm) SCX12-S0004 SCX12-S0011 SCX12-S lpm (21 gpm) SCX12-S0005 SCX12-S0012 SCX12-S lpm (32 gpm) SCX12-S0006 SCX12-S0013 SCX12-S0020 Full Flow SCX12-S0007 SCX12-S0014 SCX12-S0021 Full Motor Spool Part Number MANUALLY OPERATED HYDRAULICALLY OPERATED ELECTROHYDRAULICALLY OPERATED 5

7 STANDARD SPOOL FLOW RATES 300 SCX120 STANDARD SPOOLS WORK PORT FLOW VERSUS PUMP-LS DIFFERENTIAL PRESSURE 250 Full Flow Work Port Flow (lpm) lpm (32 gpm) Spool 80 lpm (21 gpm) Spool Pump-LS Differential Pressure (bar) 50 lpm (13 gpm) Spool 30 lpm (8 gpm) Spool 15 lpm (4 gpm) Spool 5 lpm (1 gpm) Spool SCX120 STANDARD SPOOLS WORK PORT FLOWS VERSUS TRAVEL 180 Full Flow Spool lpm (32 gpm) Spool Flow (lpm) lpm (21 gpm) Spool Spool Travel (mm) 50 lpm (13 gpm) Spool 30 lpm (8 gpm) Spool 15 lpm (4 gpm) Spool 5 lpm (1 gpm) Spool 6

8 STANDARD SPOOL PRESSURE DROPS (INLET TO WORK PORT) AND COMPENSATOR PERFORMANCE SCX120 STANDARD SPOOLS INLET TO WORK PORT PRESSURE DROP Pressure Differential (bar) lpm (1 gpm) 30 Spool lpm (8 gpm) 15 lpm (4 gpm) Spool Spool 50 lpm (13 gpm) Spool 80 lpm (21 gpm) Spool 120 lpm (32 gpm) Spool Full Flow Spool Work Port Flow (lpm) 7

9 STANDARD SPOOL PRESSURE DROPS (WORK PORT TO OUTLET) INLET TO WORK PORT PRESSURE DROPS SCX120 FULL FLOW SPOOLS INLET TO WORK PORT PRESSURE DROP PUMPING INTO INLET HOUSING 100 SCX120 FULL FLOW SPOOLS INLET TO WORK PORT PRESSURE DROP PUMPING INTO OUTLET HOUSING Pressure Differential (bar) Section 10 Section 1 Pressure Differential (bar) Section 1 Section Inlet Flow (lpm) Inlet Flow (lpm) WORK PORT TO OUTLET PRESSURE DROPS SCX120 FULL FLOW SPOOLS WORK PORT TO OUTLET PRESSURE DROP FLOWING OUT OF INLET HOUSING SCX120 FULL FLOW SPOOLS WORK PORT TO OUTLET PRESSURE DROP FLOWING OUT OF OUTLET HOUSING Pressure Differential (bar) Pressure Differential (bar) Section 10 Section Section 1 Section Work Port Flow (lpm) Work Port Flow (lpm) 8

10 INLET SECTION ASSEMBLY OPTIONS SCX121-E INLET SECTION ASSEMBLIES Designed for use with variable displacement, pressure-compensated load-sensing pumps Inlets come standard with a load sense relief valve cavity machined for the load sense relief valve Inlet comes standard with an inlet pressure relief valve cavity machined for the series relief valve, relief valve or shut off plug See table below for port options INLET SECTION ASSEMBLY END INLET PORT END OUTLET PORT LS TOP INLET PORT TOP OUTLET PORT 9 9 SCX121-A3 1-5/16-12 (SAE 16) 1-5/16-12 (SAE 16) 9/16-18 (SAE 6) 1-1/16-12 (SAE 12) 1-1/16-12 (SAE 12) SCX121-A /16-18 (SAE 6) 1-1/16-12 (SAE 12) 1-1/16-12 (SAE 12)

11 INLET SECTION ASSEMBLY OPTIONS SCX121-C INLET SECTION ASSEMBLY (UNLOADER / BYPASS COMPENSATOR INLET) Designed for use with fixed displacement pumps Unloader has a standard 15 bar (215 psi) bias spring to create pump-to-ls differential pressure Inlet comes standard with a load sense relief valve cavity machined for the load sense relief valve Inlet comes standard with an inlet pressure relief valve cavity machined for the series relief valve, relief valve or shut off plug See table below for port options IInlet to Outlet Pressure Differential (bar) UNLOADER INLET (BYPASS COMPENSATOR) PERFORMANCE Inlet Flow (gpm) IInlet to Outlet Pressure Differential (psid) Inlet Flow (lpm) INLET SECTION ASSEMBLY END INLET PORT END OUTLET PORT LOAD SENSE PORT TOP INLET PORT TOP OUTLET PORT SCX121-C3 1-1/16-12 (SAE 12) 1-5/16-12 (SAE 16) 9/16-18 (SAE 6) 1-1/16-12 (SAE 12) 1-1/16-12 (SAE 12) 10

12 SPOOL SECTION ASSEMBLY OPTIONS All SCX120 catalog spool section assemblies come with the following standard features: 1-1/16-12 (SAE 12) Work Ports Work port circuit relief valve cavities machined for both A port and B port Independent load hold check Independent compensator spool 3-position spool section assemblies are available with the following control options: Manual, spring-centered Hydraulically pilot operated Proportional or on/off electrohydraulically operated Electrohydraulically operated with manual lever The following options are available for 3-position section assemblies: Auxiliary relief valve assemblies Spool stroke limiter assembly Spool manual override/stroke limiter assembly 11 The series of Tie Rod Kits include the standard tie rod part numbers and nuts required to build SCX120 valve assemblies. Tie rod kits for valve stacks of eight, nine or ten section assemblies come with compression washers (recommended for stacks with eight or more working sections). TIE ROD KITS Part Number Valve Assembly Size Part Number Valve Assembly Size Section Sections Sections Sections Sections Sections Sections Sections Sections Sections

13 SPOOL SECTION ASSEMBLY OPTIONS SPOOL SECTION ASSEMBLY ORDERING NOMENCLATURE SCX122 - S E C T I O N C O D E S P O O L C O D E The table below contains the SPOOL CODES for 3-position Spool Type Spool Flow Rate lpm (gpm) Spool Code Cylinder Spool 5 lpm (1 gpm) lpm (4 gpm) lpm (8 gpm) lpm (13 gpm) lpm (21 gpm) lpm (32 gpm) 006 Full Flow 007 Restricted Motor 5 lpm (1 gpm) lpm (4 gpm) lpm (8 gpm) lpm (13 gpm) lpm (21 gpm) lpm (32 gpm) 013 Full Flow 014 Full Motor 5 lpm (1 gpm) lpm (4 gpm) lpm (8 gpm) lpm (13 gpm) lpm (21 gpm) lpm (32 gpm) 020 Full Flow

14 SPOOL SECTION ASSEMBLY OPTIONS 3-POSITION, MANUAL, RIGHT-HANDED SECTION ASSEMBLIES Standard sections shipped as right hand assemblies Convertable to left hand assemblies by switching spool end components SECTION CODE A-A WORK PORT 7/8-14 (SAE 10) 13

15 SPOOL SECTION ASSEMBLY OPTIONS 3-POSITION, HYDRAULICALLY OPERATED SECTION ASSEMBLIES Section assemblies use 25 bar (360 psi) centering springs, for use with the standard HUSCO pilot pressure controller See page 23 for spool stroke limiter and manual override options SECTION CODE A-B WORK PORT 7/8-14 (SAE 10) 14

16 SPOOL SECTION ASSEMBLY OPTIONS 3-POSITION, ELECTROHYDRAULICALLY OPERATED SECTION ASSEMBLIES Electrohydraulic section assemblies use HUSCO manufactured proportional pressure reducing valves (EPRV). The standard section assemblies come with the D20 installed, which have integrated Deutsch DT04-2P female connectors Section assemblies come with o-ring port plug assemblies installed in end pilot ports Standard section assemblies come with end pilot ports and 9/16-18 (SAE 6) o-ring port plug assemblies installed Pilot supply pressure feeding EH sections should be a minimum of 25 bar (362 psi) to ensure full spool shift. Maximum pilot supply pressure feeding EH sections should not exceed 250 bar (3,625 psi). Sump gallery connected to EPRV s should not exceed 7 bar (100 psi). See page 23 for spool stroke limiter and manual override options See page 21 for other EPRV options SECTION CODE E-A WORK PORT 7/8-14 (SAE 10) 15

17 SPOOL SECTION ASSEMBLY OPTIONS 3-POSITION, ELECTROHYDRAULICALLY OPERATED SECTION ASSEMBLIES Electrohydraulic section assemblies use HUSCO manufactured proportional pressure reducing valves (EPRV). The standard section assemblies come with the D20 installed, which have integrated Deutsch DT04-2P female connectors Section assemblies come with o-ring port plug assemblies installed in end pilot ports Standard section assemblies come with end pilot ports and 9/16-18 (SAE 6) o-ring port plug assemblies installed Pilot supply pressure feeding EH sections should be a minimum of 25 bar (362 psi) to ensure full spool shift. Maximum pilot supply pressure feeding EH sections should not exceed 250 bar (3,625 psi). Sump gallery connected to EPRV s should not exceed 7 bar (100 psi). See page 23 for spool stroke limiter and manual override options See page 21 for other EPRV options SECTION CODE E-B WORK PORT 7/8-14 (SAE 10) 16

18 OUTLET SECTION ASSEMBLY OPTIONS Outlets are available with the following options: No EH machining (end cover only) EH machining for pump pressure to feed EH pilot supply rails from internal pump rail* *NOTE: when using pump pressure to directly supply EH sections, inlet pressure must be limited to 250 bar (3,625 psi), to prevent exceeding the maximum supply pressure to the EPRVs EH machining for external pilot pressure supply to be fed into SCX120 valve to feed EH supply rails See table below for port options SCX123-A OUTLET SECTION ASSEMBLIES 17 OUTLET SECTION ASSEMBLY INLET END PORT OUTLET END PORT LOAD SENSE PORT PILOT PORT SUMP PORT SCX123-A SCX123-A3 1-1/16-12 (SAE 12) 1 5/16-12 (SAE 16) 9/16-18 (SAE 6) SCX123-A /16-18 (SAE 6) 9/16-18 (SAE 6) SCX123-A5 1-1/16-12 (SAE 12) 1-5/16-12 (SAE 16) 9/16-18 (SAE 6) 9/16-18 (SAE 6) 9/16-18 (SAE 6) SCX123-A /16-18 (SAE 6) 9/16-18 (SAE 6) SCX123-A7 1-1/16-12 (SAE 12) 1 5/16-12 (SAE 16) 9/16-18 (SAE 6) 9/16-18 (SAE 6) 9/16-18 (SAE 6) 16

19 OUTLET SECTION ASSEMBLY OPTIONS SCX123-B OUTLET SECTION ASSEMBLIES The SCX123-B outlets come standard with machined cavity for pressure reducing valve for the purpose of generating a low pressure pilot supply for EH spool sections and for supplying external devices such as pilot circuits - See page 22 for options. See table below for port options OUTLET SECTION ASSEMBLY INLET PORT OUTLET PORT SUMP PORT PILOT SUPPLY PORT LOAD SENSE SCX123-B4 1-5/16-12 (SAE 16) 1-5/16-12 (SAE 16) 9/16-18 (SAE 6) 9/16-18 (SAE 6) 9/16-18 (SAE 6) SCX123-B /16-18 (SAE 6) 9/16-18 (SAE 6)

20 RELIEF VALVES, END MECHANISMS AND KITS LOAD SENSE RELIEF VALVE AND DRAIN REGULATOR ASSEMBLY The is the standard load sense relief valve for the SCX120 valve line. Installed into the inlet housing, it limits the maximum LS pressure, which therefore limits the maximum inlet (P) pressure also has an integrated pressure compensated LS drain, which drains off LS pressure when none of the spools are selected. The relief valve is protected against contamination with an integrated 100μ filter has a setting range of bar (900-4,350 psi). The standard catalog setting for is 214 bar (3,100 psi) and can be adjusted to suit the requirements needed for each application. SURGE WORK PORT RELIEF VALVE ASSEMBLY The Relief Valve Assembly is a direct acting relief valve with integrated anti-void (anti-cavitation) function and is the standard work port relief valve option (shock valve). The can also be used in some inlet housings to prevent fast inlet (P) pressure spikes from damaging the main control valve or the rest of the hydraulic system. Relief valves are set at 10 lpm (2.6 gpm) and have a recommended maximum flow rate of 75 lpm (19.8 gpm). The relief valve setting is stamped on the RV plug (for example: 200 = a setting of 200 bar (2,900 psi)). Part Number Setting (bar) Setting (psi) , , , , , , ,000 ANTI-VOID (ANTI-CAVITATION) PERFORMANCE Flow (gpm) Flow (gpm) Pressure Drop (bar) Flow (lpm) Pressure Drop (psid) Pressure Drop (bar) Flow (lpm) Pressure Drop (psid) 18 Consult HUSCO Sales department for non-standard RV settings.

21 RELIEF VALVES, END MECHANISMS AND KITS WORK PORT RELIEF VALVE ASSEMBLY The relief valve is an adjustable differential area relief valve designed to work in the as a work port relief valve or a main relief valve for the SCX120 platform. The standard setting for the relief valve is 165 bar (2400 psi) set at 19 lpm (5 gpm). The can be adjusted between bar ( psi). The max flow for the is 151 lpm (40 gpm). Please contact the factory for more information. WORK PORT ANTI-VOID (ANTI-CAVITATION) VALVE ASSEMBLY AND SHUT-OFF PLUG ASSEMBLY The is the standard anti-void assembly, designed to prevent cavitation in the valve work port. The has AV stamped on the plug. The is the standard shut-off plug assembly, designed to block off the work port RV cavity when no RV is required and the inlet (P) pressure RV cavity when no inlet RV is required. MANUAL LEVER ASSEMBLY The manual lever assembly is available for use with the SCX122-a-a family of sections. The handle assembly kit is available for use with the lever assembly or OEMs can provide their own handle to mate with the simple thread interface

22 RELIEF VALVES, END MECHANISMS AND KITS ELECTROHYDRAULIC PRESSURE REDUCING VALVES (EPRV) HUSCO Electrohydraulic Pressure Reducing Valves (EPRV) are IP69 rated and come with an integraded 100μ filter on the pilot pressure supply ( B ) gallery of the EPRV. HUSCO EPRVs work with a maximum supply pressure of 250 bar (3,625 psi), require a 100 Hz PWM command signal and can operate in a temperature range of -30 C to 120 C (oil temp) and -30 C to 80 C (amibent air temp). The EPRV electrical coil has a 100% duty cycle rating and a Class H insulation rating. The sump port on the main control valve assembly should be connected to the system reservoir with a minimum amount of back pressure (a maximum back pressure of 7 bar (100 psi) is reccommended). EPRVs can be used for either proportional control or on-off ( bang-bang ) control. See table below for connector style, threshold current & pressure, maximum current & pressure resistance characteristics. EPRV Part No D D D D A20 Connector Style Connector Color Voltage (VDC) Resistance at 20 C (Ω) Threshold Current (ma) Maximum Current (ma) Threshold Control Pressure (bar) Maximum Control Pressure (bar) Deutsch DT04-2P Black ± ± Deutsch DT04-2P Natural (beige) ± ± Deutsch DT04-2P Blue ± ± Deutsch DT04-2P Grey ± ± Amp Junior Power Timer Black ± ± ELECTROHYDRAULIC CONVERSION ASSEMBLY KIT The Conversion Kits will plug the EH solenoid cavity on EH sections and provides a port for connecting pilot pressure to the spool spring chamber in order to shift the spool as a hydraulically pilot operated section. The kit allows a section assembly to be electrically prepared (machined for EPRV solenoid valves but built to be hydraulically pilot operated). When a customer wants to update from pilot operated control to EH control, the section can be easily upgraded to EH in the field without the need for a costly valve removal Part Number Pilot Port 9/16-18 (SAE 6) ISO G1/4

23 RELIEF VALVES, END MECHANISMS AND KITS PRESSURE REDUCING VALVE ASSEMBLY FOR PILOT PRESSURE SUPPLY The pressure reducing valve reduces inlet (P) pressure down to down to a lower pressure pilot supply. It is used in the SCX123-B Outlet Section Assemblies for SCX120 valve assemblies that require internal or external pilot pressure supply comes with 30 bar (435 psi) nominal pressure setting and can be adjusted between 10.3 bar (150 psi) to 40.0 bar (550 psi). The valve is protected against contamination with an integrated 100μ filter. A PRESSURE REDUCING VALVE SHUT-OFF PLUG ASSEMBLY A series of shut-off plug assemblies are available to plug the pressure reducing valve cavity in SCX123-B Outlet Section Assemblies, in case the pressure reducing valve is not required. Part Number Pilot Supply Source * Inlet Supply External Supply 9/16-18 (SAE 6) Port External Supply ISO G 1/4 Port *Note: When using the Shut-Off Plug, inlet pressure must be limited to 250 bar (3,625 psi) maximum, to prevent exceeding the maximum supply pressure supplied to the EPRVs. END MECHANISM KITS FOR 3-POSITION HYDRAULICALLY PILOT OPERATED SECTIONS The SCX120 end mechanisms for hydraulically pilot operated sections come standard with a 25 bar (360 psi) centering spring and 9/16-18 (SAE 6) o-ring ports for connecting to a hydraulic pilot joystick. Kits are available with three different porting options: end port only, side port only, or both end port and side port. 23 END PORT ONLY SIDE PORT ONLY END AND SIDE PORT

24 RELIEF VALVES, END MECHANISMS AND KITS ADJUSTABLE STROKE LIMITER KIT AND MANUAL OVERRIDE KIT The Manual Override Kit provides a way to manually shift a spool far enough to lower a machine implement in case of a dead engine situation. It also provides the function of the adjustable stroke limiter and allows the manual override adjustment to be made independent of the stoke limiting adjustment. TANG END & SEAL PLATE KITS FOR MANUAL SECTIONS CLEVIS END & SEAL KIT TANG END & SEAL KIT

25 APPENDIX 1 OPEN CENTER VERSUS CLOSED CENTER The following hydraulic circuits & graphs represent efficiency gains going from an open center valve with fixed displacement pump to a closed center valve with inlet unloader (bypass compensator) with fixed displacement pump to a closed center valve with pressure-compensated load-sensing variable displacement pump. The following table compares the system costs and efficiencies of an open center system, a closed center system with unloader (bypass compensator) and a closed center system with a pressure-compensated load-sensing variable displacement pump. Open Center System Fixed displacement pump Pressure differential across spool depends on flow System Cost $ Efficiency 25 Unloader (Bypass Compensator) System Fixed displacement pump Unloader (bypass compensator) spool diverts excess flow Constant pressure differential maintained Pressure Compensated Load Sense System (PCLS) Variable displacement pump Load sensing valve Pump flow varied to maintain constant pressure differential $$ $$$ 24

26 APPENDIX 2 POST-COMPENSATED VERSUS PRE-COMPENSATED The following hydraulic circuits represent the basic design of post-pressure compensated and pre-pressure compensated closed center valve systems. There are several differences in the two styles of valve design, which are determined by the basic valve geometry and design. The most noticeable difference however, is that post-compensated valves continue to offer excellent flow sharing when flow demand exceeds flow supply, while pre-compensated valves will only meet the flow demands of the lowest loaded functions (causing higher loaded functions to slow down or stop moving). 25 TRADITIONAL POST-PRESSURE COMPENSATED CIRCUIT Key Features: Pressure differential acting on the compensator spool is picked downstream of the main spool metering orifice Load sense signal from each function is picked up before the load sense shuttle All compensator spools reference the same resolved load sense signal Key feature for maintaining flow sharing Pump to load sense pressure differential is controlled by the pump or the inlet unloader (bypass compensator) Resulting Characteristics: When flow demand exceeds flow supply, the compensators will split the pump flow to all functions proportional to the main spool metering orifice of each spool Great flow sharing, even when exceeding flow supply. Maximum function pressure is limited using optional auxiliary relief valves Load Sense pressure limiting on individual functions is not available TRADITIONAL PRE-PRESSURE COMPENSATED CIRCUIT Key Features: Pressure differential acting on the compensator spool is picked from either side of the main metering orifice Load sense signal from each function is picked up after the load sense shuttle Compensator spools reference a load sense signal picked up before the load sense shuttle Allows load sense pressure limiting on individual functions Pump to load sense pressure differential is controlled by the compensator springs Resulting Characteristics: When flow demand exceeds flow supply, the lowest loaded functions will take priority over the highest loaded function Highest loaded functions may stop moving, depending on flow demand 26

27 HUSCO OVERVIEW For over 60 years, HUSCO International has been designing and producing innovative and high performance hydraulic and electrohydraulic products in the agriculture, construction, forestry and material handling industry. Today HUSCO control products can be found on a variety of leading off-highway equipment throughout the world. Dedicated to meeting and exceeding the changing control needs of the off-highway market for today and well into the future, HUSCO employs an extensive engineering staff for the design of platform and customized products to provide costeffective solutions to maximize the efficiency, productivity, controllability and reliability of vehicles. HUSCO s extensive global engineering and vehicle fit-up and testing capabilities enable HUSCO to be an extension of OEM engineering teams to provide fast response and efficient solutions to global and regional market demands. This reduces product development cycles, improves the end product, and has led to HUSCO becoming a global hydraulic controls leader. Visit the HUSCO website at for a complete list of HUSCO sales offices and distributors.

28 HUSCO WORLDWIDE World Headquarters HUSCO International, Inc Pewaukee Road Waukesha, WI Phone: Fax: European Headquarters HUSCO International, Ltd. 6 Rivington Road Whitehouse Industries Estate Runcorn, Cheshire, England WA7 3DT Phone:(44) Fax: (44) Whitewater Operations HUSCO International, Inc Universal Boulevard Whitewater, WI Phone: Fax: Iowa Operations HUSCO International, Inc. 104 Generac Drive Maquoketa, IA Phone: Fax: HUSCO Brazil Rua Jaragua 397 sala 702 Porto Alegre RS Brazil Phone: (55) Fax: (55) Locally Focused

29 CONTROL FOCUSED - TECHNOLOGY DRIVEN China Headquarters HUSCO Hydraulics (Shanghai) Ltd. No. 235 Jiangtian Road East Song Jiang Industrial Zone Shanghai, India Headquarters HUSCO Hydraulics Pvt, Ltd. Plot A4-Talegaon Industrial Area Pune, maharastra , India Phone: (91) Fax: (91) Globally Driven 28

30 NOTES 29

31 NOTES 30

32 CONTROL FOCUSED TECHNOLOGY DRIVEN THE SCX PLATFORM IS A FAMILY OF CLOSED CENTER POST-PRESSURE COMPENSATED SECTIONAL VALVES DESIGNED SPECIFICALLY FOR THE CONSTRUCTION, MATERIAL HANDLING, AND FORESTRY EQUIPMENT MARKETS. THE SCX PLATFORM IS AVAILABLE IN THREE DIFFERENT SIZES: SCX120, SCX180 AND SCX300. World Headquarters HUSCO International, Inc Pewaukee Road Waukesha, WI Phone: Fax: European Headquarters HUSCO International, Ltd. 6 Rivington Road Whitehouse Industrial Estate Runcorn, Cheshire, England WA7 3DT Phone: (44) Fax: (44) China Headquarters HUSCO Hydraulics (Shanghai) Ltd. No. 235 Jiangtian Road East Song Jiang Industrial Zone Shanghai, P.R. China Phone: (86) Fax: (86) India Headquarters HUSCO Hydraulics Private Ltd. Plot A4 - Talegaon Floriculture Ind. Estate - MIDC Village - Navlakh Umbre, Talegaon, Puna , India Phone: (91) HUSCO Brazil Rua Jaragua 397 sala 702 Porto Alegre RS Brazil Phone: (55) Fax: (55) HUSCO International