Walvoil SD25/2/AC(XG-250)/111L/28L/RC is a sectional 2 Spool Hydraulic Valve for mobile equipment rated at 240 L/min nominal flow and up to 315 bar maximum pressure.Configured as an Open Center Hydraulic Valve with manual lever actuation,it controls hydraulic cylinders and motors on agricultural loaders,cranes,and earth-moving machinery.The valve per manufacturer specifications delivers threaded connections at G1 port size for high-flow hydraulic circuits.

　　What Is an Open Center Hydraulic Valve?

　　An Open Center Hydraulic Valve is a directional control valve in which the pump flow circulates freely from the pump port(P)to the tank port(T)when all spools are in the neutral position.This configuration suits hydraulic systems using fixed-displacement pumps,where a continuous flow path through the valve center prevents pressure build-up during idle,thereby minimizing energy losses and thermal loading when no work functions are active.

　　Open center valves may be classified by construction type,including monoblock and sectional architectures.The Walvoil SD25 series is a sectional valve,meaning individual working sections plus an inlet element and an outlet element are bolted together with tie rods.Each working section contains a load check valve and supports retrofitting of auxiliary cartridge valves for pressure relief,anti-cavitation,and motion control functions.

　　Key Specifications

　　Valve Type:2 Spool Open Center Hydraulic Valve,Sectional Construction

　　Inlet Element:SD25/2/AC(XG-250)

　　AC(XG)Inlet Designation:Open Center Inlet with Main Pressure Relief Valve Set at 250 bar

　　Working Section 1:111L—Double-Acting with Spring Return to Neutral

　　Working Section 2:28L—Double-Acting with Spring Return to Neutral

　　Outlet Element:RC—Side Port Outlet(Right Side)

　　Nominal Flow Rating:240 L/min(63 US gpm)

　　Maximum Pressure:315 bar(4,600 psi)

　　Main Relief Valve Setting(Inlet):250 bar

　　Tank Port Back Pressure Rating:25 bar(T port,per manufacturer datasheet)

　　Number of Spools:2

　　Control Type:Manual Lever,Spring Return

　　Hydraulic Circuit Type:Open Center(Neutral Position PT Ports Connected)

　　Nominal Flow per Working Section:140 L/min(G 3/4″port configuration)

　　Port Size P,A,B:G 1″

　　Port Size T:G 1 1/4″

　　Oil Temperature Range:-15°C to+80°C

　　Contamination Level Requirement:-/19/16 per ISO 4406

　　Internal Leakage:Approximately 4 cm³/min at 100 bar

　　Housing Material:Special Cast Iron

　　Spool Material:Steel

　　Seal Material:NBR(Nitrile Butadiene Rubber)

　　Tie Rod Tightening Torque:50 Nm

　　Weight:Approximately 18 kg(assembly)

　　Operating Pressure Range:Up to 315 bar(maximum)

　　Inlet and Working Section Compatibility:SD25 Series Components,Interchangeable with Tie Rod Assembly

　　Technical Highlights

　　The sectional architecture with tie rod assembly enables field-level customization.Each working section installs between the inlet and outlet elements and fastens via tie rods torqued to 50 Nm.This design allows addition,removal,or reordering of sections to match changing machine hydraulic requirements without replacing the entire valve assembly.

　　The main pressure relief valve integrated into the AC(XG)inlet element provides primary system overpressure protection.Set at 250 bar(with field adjustability to the valve maximum pressure of 315 bar),this direct-acting relief valve diverts excess flow to tank when system pressure reaches the set point,protecting downstream components including cylinders and hoses from overpressure damage.

　　Load check valves on every working section prevent unintended load drop during spool shifting.When a spool moves from neutral to the work position,the load check valve remains closed until pump-side pressure exceeds the work port pressure,thereby preventing reverse flow from the actuator to the pump gallery—a critical feature for lifting and holding applications on cranes and loader booms.

　　The 111L and 28L spool designations specify double-acting spools with spring return to neutral,ensuring that uncontrolled cylinder movement stops when the operator releases the lever.This spring-centered configuration is the standard fail-safe arrangement for mobile equipment directional control,meeting operational safety requirements on agricultural and construction machinery.

　　NBR seals combined with cast iron housing provide-15°C to+80°C operating range,supporting outdoor mobile equipment applications in cold-start conditions as well as sustained operation in high-ambient environments.Is the SD25 series tested to specific industry standards?The valve contamination level requirement is specified as-/19/16 in accordance with ISO 4406,with internal leakage validated at approximately 4 cm³/min at 100 bar system pressure.

　　Applications

　　Agricultural loader implement control:Directs hydraulic flow to lift and tilt cylinders on tractor-mounted loaders.The 240 L/min flow capacity supports rapid cycle times for bucket loading operations,reducing operator waiting time at the pile.

　　All-terrain crane boom and outrigger circuits:Controls telescope extension,boom elevation,and stabilizer deployment.The open center configuration maintains low standby pressure during transport between lifts,reducing heat generation in continuous-duty crane operations.

　　Earth-moving machine auxiliary functions:Operates attachments such as grapples,tilt buckets,and hydraulic thumbs on excavators and backhoes.The double-acting spool configuration(111L and 28L designations)provides bidirectional hydraulic flow for powered attachment open and close cycles.

　　Material handling forklift mast and sideshift control:Manages lift cylinder actuation and side-shift carriage positioning on large container forklifts and stackers,where Walvoil identifies the SD25 series as a specified application per manufacturer application documentation.

　　Garbage compactor compaction and ejection circuits:Controls the hydraulic cylinders responsible for waste compaction and load ejection.The sectional valve’s capacity for auxiliary cartridge valve integration supports addition of anti-cavitation and shock relief protection for high-inertia compaction cycles.

　　Selection Guidance

　　Suitable applications:

　　Hydraulic systems using fixed-displacement gear pumps below 240 L/min flow,where open center neutral oil circulation reduces idle power consumption

　　Mobile equipment requiring 2-spool directional control with double-acting cylinder operation and spring return to neutral for operator safety

　　Field-modifiable valve assemblies where the sectional tie rod design permits spool configuration changes,section additions,or pressure relief cartridge retrofits after initial installation

　　System designs requiring G1″work port connections and G1 1/4″tank port connections for large-diameter hydraulic lines on high-flow circuits

　　Not recommended for:

　　Closed-center or load-sensing hydraulic systems that operate with variable-displacement pumps.For these applications,select the Walvoil DPX or DPC series load-sensing sectional valves,which provide pressure-compensated flow control and reduced energy consumption under partial-load conditions.

　　Single-spool control requirements where a monoblock valve provides a more compact and cost-effective solution.The Walvoil SDM142 or SDM105 monoblock directional control valve series offers single-section configurations with similar flow capacity in a smaller footprint.

　　Systems requiring electro-proportional remote control actuation.The SD25/2/AC(XG-250)/111L/28L/RC is a manually operated valve with lever actuation only.For proportional solenoid or hydraulic pilot-actuated control,consult Walvoil electro-hydraulic sectional valve options available through Beijing Zhongping Technology.

　　FAQ

　　1.What are the dimensions and weight of the SD25/2/AC(XG-250)/111L/28L/RC valve assembly?

　　The assembled 2-spool configuration weighs approximately 18 kg.The individual inlet element SD-25-AC(XG)weighs 8.98 kg per manufacturer datasheet,and each working section adds approximately 4.5 kg.Overall assembly dimensions depend on the number of sections and port orientation,and we provide installation drawings upon request.

　　2.What is the delivery time or lead time for this Walvoil valve configuration?

　　Standard manufacturer lead time is 6 to 8 weeks for assembled valve configurations with specified spool combinations.Beijing Zhongping Technology stocks common SD25 inlet elements,working sections,and outlet elements for expedited assembly and delivery within 2 to 3 weeks.

　　3.Is the Walvoil SD25/2/AC(XG-250)/111L/28L/RC in stock or available for immediate shipment?

　　This specific spool configuration is assembled to order rather than held as a finished assembly in stock.Beijing Zhongping Technology maintains inventory of SD25 series components including AC(XG)inlet elements and common working sections,enabling fast assembly turnaround for specified configurations.

　　4.What certifications and quality standards apply to Walvoil SD25 sectional valves?

　　Walvoil S.p.A.operates under ISO 9001 quality management system certification.SD25 series valves comply with ISO 4406 contamination level requirements(-/19/16)and CETOP dimensional standards for hydraulic valve port interfaces.The manufacturer maintains full material traceability and pressure testing records for each assembled valve.

　　5.How much does the SD25/2/AC(XG-250)/111L/28L/RC cost,and what is the price range?

　　The assembled 2-spool sectional valve typically ranges from 1,800to3,200 USD depending on spool configuration,relief valve settings,and included accessories.Prices fluctuate due to exchange rates,tariffs,and factory adjustments.For an accurate quotation with current pricing,contact Beijing Zhongping Technology directly.

　　6.What payment methods and payment terms do you accept for Walvoil valve orders?

　　We accept bank wire transfer(T/T),irrevocable letter of credit(L/C)at sight for orders over$10,000,and major credit cards for smaller purchases.For qualified corporate accounts,Beijing Zhongping Technology offers net 30 payment terms upon credit approval.

　　7.What hydraulic oil is compatible,and what filtration is required for the SD25 series?

　　The valve operates with standard mineral-based hydraulic oils(HL,HLP per DIN 51524)within-15°C to+80°C temperature range.The required oil cleanliness level is-/19/16 per ISO 4406.We recommend a system return line filter withβ₁₀≥75 rating and advise that operating with cleaner fluid extends spool and seal service life.

　　8.What is the warranty period and return policy for Walvoil sectional valves?

　　We provide a 12-month warranty against manufacturing defects from the date of shipment.Custom-assembled valve configurations(including this model)are built to specification and are non-returnable once assembled.Beijing Zhongping Technology provides pre-assembly configuration verification to ensure correct spool selection before manufacturing.

　　9.Can I get spare parts,seal kits,or individual working sections separately?

　　We supply individual SD25 working sections,inlet elements,outlet elements,seal kits,tie rods,and auxiliary cartridge valves as separate spare parts.Beijing Zhongping Technology stocks replacement seals,O-rings,relief valve cartridges,and spool assemblies for field maintenance and valve reconfiguration without replacing the complete assembly.

　　10.What are the import duty,HTS code,and customs clearance requirements for Walvoil valves?

　　The Harmonized Tariff Schedule code for hydraulic directional control valves is 8481.20.0010.International shipments dispatch from Italy under Incoterms EXW(Ex Works)or FCA(Free Carrier)unless otherwise negotiated.Duties,customs fees,and applicable VAT are payable by the buyer upon import.Beijing Zhongping Technology provides commercial invoices,packing lists,and certificates of origin required for customs clearance on all export orders.