YOULI MB-3 series is a 3 Spool Hydraulic Control Valve in a monoblock design,engineered as a Double Acting Hydraulic Valve for mobile and industrial directional control.With a nominal flow of 45 L/min(12 US gpm)and maximum operating pressure of 315 bar(4,600 psi)in parallel circuit,it supplies hydraulic flow to double-acting cylinders,hydraulic motors,and outrigger circuits on agricultural machinery,sanitation vehicles,construction equipment,and drilling rigs.

　　What Is a 3 Spool Hydraulic Control Valve?

　　A 3 spool hydraulic control valve—also called a three-section monoblock directional valve—is a single-piece hydraulic component with three independent spools that direct pressurized oil to different actuator circuits from a shared inlet.Each spool controls the start,stop,and direction of fluid flow to one hydraulic function,such as a cylinder extend/retract or a motor forward/reverse.

　　In mobile and industrial hydraulics,three-spool valves serve applications requiring simultaneous or sequential control of three separate functions—for example,lifting,tilting,and clamping on a work platform.The monoblock construction eliminates inter-section seals and external tie rods,reducing potential leak paths compared to sectional valves.The MB-3 series specifically offers parallel circuit architecture as standard,ensuring that shifting one spool does not starve the remaining spools of flow—a critical requirement when two or three functions must operate concurrently under varying loads.

　　Key Specifications

　　Nominal Flow Rate:45 L/min(12 US gpm)

　　Maximum Operating Pressure(Parallel Circuit):315 bar(4,600 psi)

　　Maximum Operating Pressure(Series Circuit):210 bar(3,050 psi)

　　Maximum Back Pressure(Outlet Port T):25 bar(360 psi)

　　Number of Spools(Sections):1 to 6 spool configurations available;3-spool being a standard configuration

　　Valve Construction:Monoblock(one-piece cast iron body)

　　Spool Action:Spring return to neutral(standard)

　　Spool Configurations:Double acting,3-position(A&B closed in neutral);single acting;motor spool;float(4th position)available

　　Control Method:Manual lever(standard);pneumatic,hydraulic pilot,and electro-hydraulic options available

　　Load Check Valve:Included in each section(standard)

　　Port Size:G3/8"BSP(British Standard Pipe Parallel)

　　Mounting Type:Sub-plate mounting

　　Fluid Temperature Range(NBR Seals):-20°C to 80°C(-4°F to 176°F)

　　Fluid Temperature Range(FPM/Viton Seals):-20°C to 100°C(-4°F to 212°F)

　　Ambient Temperature Range:-40°C to 60°C(-40°F to 140°F)

　　Viscosity Operating Range:15 to 75 mm²/s(15 to 75 cSt)

　　Minimum Viscosity:12 mm²/s(12 cSt)

　　Maximum Viscosity:400 mm²/s(400 cSt)

　　Approximate Dimensions(3-Spool Configuration):23.9 cm×22.1 cm×8.45 cm(L×W×H)

　　Body Material:Cast iron(EN-GJL300)

　　Spool Material:Hardened and ground steel

　　Quality Testing:100%factory tested on flow,pressure,oil leakage,and motion smoothness per manufacturer test protocol

　　Technical Highlights

　　Monoblock body eliminates inter-section leak paths.The single-piece cast iron housing contains all three spool bores within a continuous block.Unlike sectional valves assembled with tie rods and inter-section O-rings,this architecture removes the sealing interfaces that are most prone to external oil weeping after years of thermal cycling and vibration.For mobile equipment where hydraulic leaks create safety and environmental hazards,this design directly reduces the number of potential leak points.This addresses the common question:"Does the MB-3 leak between sections?"—the monoblock construction inherently prevents inter-section leakage.

　　Hardened spools with precision grinding maintain long-term metering accuracy.Each spool is hardened then ground to tight clearance within its bore.This extends service life in applications with high cycle rates—such as garbage truck compactor sequencing or agricultural implement positioning—where spool wear in softer valves leads to increasing internal bypass leakage and deteriorating control precision over time.

　　Independent load check valve per section prevents unintended load drift.Each spool circuit integrates a dedicated load check valve that blocks reverse flow when the spool shifts.This prevents a loaded cylinder from momentarily dropping as the spool transitions from neutral to working position—a critical safety feature for lifting and outrigger applications.

　　Spring-return mechanism defaults all spools to neutral.Each spool returns to center(neutral)position automatically when the operator releases the lever,stopping all flow to that actuator.In neutral position,A and B work ports are blocked while the P-to-T open-center passage remains open(on parallel circuit configuration),allowing pump flow to circulate at low pressure through other spool sections.

　　Applications

　　Agricultural machinery implement control:Directs hydraulic flow to lift/lower,angle/tilt,and fold cylinders on tractors,sprayers,and tillage equipment.The spring-return spools default to neutral when the operator releases the lever,holding implement position without continuous lever pressure.

　　Sanitation truck compactor and lift circuits:Controls tailgate lift cylinders,packer blade extension/retraction,and ejector panel movement on refuse collection vehicles.The 315 bar pressure rating handles peak compaction loads without relief valve bypass.

　　Outrigger and stabilizer systems:Manages multiple outrigger cylinders on mobile cranes,drilling rigs,and aerial work platforms.Individual load check valves prevent leg creep when the spool is in neutral,maintaining platform stability during operation.

　　Construction and earthmoving attachments:Provides three-function control on mini-excavator attachments,skid-steer loader auxiliary hydraulics,and backhoe thumb/boom/swing circuits.The monoblock body withstands vibration and shock loading common on construction sites.

　　Industrial material handling and lifting equipment:Sequences clamp,lift,and rotate functions on hydraulic lift tables,scissor lifts,and pallet positioners.The 45 L/min flow capacity matches standard gear pump outputs on mid-sized industrial power units.

　　Selection Guidance

　　Suitable applications:

　　Systems requiring simultaneous or independent control of up to three double-acting hydraulic functions with a single valve block—the parallel circuit architecture allows concurrent multi-function operation without flow starvation

　　Hydraulic circuits operating within 45 L/min(12 US gpm)and 315 bar(4,600 psi)limits—the MB-3 matches the output of standard 12-to-14-tooth gear pumps driven by 5–10 hp prime movers

　　Mobile equipment and industrial machinery requiring a compact,leak-resistant monoblock valve with sub-plate mounting for clean panel integration

　　Users who need flexibility in control method—manual lever operation can be supplemented or replaced with pneumatic,hydraulic pilot,or electro-hydraulic actuation using factory-supported options

　　Not recommended for:

　　Systems requiring flow rates above 55 L/min continuous.A common question during selection is whether the MB-3 can handle flows beyond 12 US gpm—the internal porting creates pressure drop above its rated flow range,reducing system efficiency.For higher flow requirements,select a larger series such as the YOULI MB-5(rated for 80 L/min)or P80 series.

　　Series circuit applications demanding 315 bar pressure rating.The MB-3 series circuit is derated to 210 bar(3,050 psi)maximum.If full 315 bar pressure must be maintained in series configuration,verify that the pressure derating is acceptable for the target system.

　　Applications where the spool must stay in a shifted position without continuous operator intervention.The standard spring-return mechanism returns all spools to neutral upon lever release.For detent-hold operation,specify a detent spool configuration(e.g.,3-position detent or 4-position float detent)in the model code at the time of order.

　　FAQ

　　1.What is the price range for the YOULI MB-3 3-spool valve,and does the quantity ordered affect unit pricing?

　　The YOULI MB-3 3-spool valve typically ranges from 120to380 USD per unit depending on spool configuration,control options,and order volume.Quantity-based tier pricing applies—a single-spool manual variant starts at approximately$119 per unit,while 3-spool configurations with double-acting spools and optional relief valves are priced higher per the manufacturer's wholesale schedule.Prices fluctuate due to exchange rates,tariffs,and factory adjustments.For an accurate quotation based on your exact model code and quantity,contact Beijing Zhongping Technology directly.

　　2.How do I decode the MB-3 model number to specify the exact spool types and control method I need?

　　The YOULI model code encodes the number of spools,spool action type,spool position configuration,port size,seal material,and control method in a structured sequence.For example,MB-3/3S-3/18L/G-3/M3 translates to:MB-3 series,3 spools(3S),3-position spools,18 L/min per-section flow limit(when flow dividers are specified),G3/8"BSP ports(G-3),and manual lever control(M3).We provide a model code selection guide at Beijing Zhongping Technology to assist with specifying the correct configuration for your hydraulic circuit.

　　3.What is the difference between the MB-3 and other YOULI series like the MB-5 or P40,and which one should I choose?

　　The MB-3 offers 45 L/min nominal flow and 315 bar maximum pressure in a compact monoblock package.The MB-5 steps up to 80 L/min for larger flow requirements.The P40 series,from a different manufacturer,provides 40 L/min at 250 bar—lower in both flow and pressure compared to the MB-3.Choose the MB-3 for mid-range flow applications;choose the MB-5 if your pump output exceeds 55 L/min;consider the P40 only if your system operates below 250 bar and a lower-cost alternative is acceptable.

　　4.Can the MB-3 3-spool valve be field-converted between parallel,tandem,and closed-center circuit types?

　　The MB-3 is factory-configured as a parallel circuit valve for simultaneous multi-function operation.Closed-center conversion requires a closed-center plug cartridge installed in the outlet section;power-beyond capability requires a power-beyond sleeve cartridge.These conversions are field-installable by a qualified hydraulic technician using the appropriate YOULI cartridge kit.You must confirm the required circuit type at the time of ordering to ensure the correct factory plug or sleeve is included.

　　5.Is the MB-3 available with joystick control or only with manual levers?

　　Manual lever control is the standard configuration.Joystick control is available through YOULI‘s factory-supported mechanical joystick kit,which replaces individual levers with a single twin-axis joystick for two-spool operation.Electro-hydraulic(solenoid-actuated)and pneumatic remote control options are also supported.You must specify the control method in the model code at the time of ordering.

　　6.How do I confirm that the YOULI MB-3 I’m purchasing is genuine and not a counterfeit or look-alike product?

　　We source YOULI MB-3 valves exclusively through the manufacturer‘s authorized distribution channel.Each valve undergoes 100%factory testing on flow,pressure,oil leakage,and motion smoothness before shipment,and genuine YOULI products carry traceable serial numbers and factory test documentation.Beijing Zhongping Technology provides a certificate of authenticity with each unit upon request,confirming the supply chain traceability back to YOULI Hydraulic Industrial Co.,Ltd.in Taichung,Taiwan.

　　7.Do you stock the MB-3 3-spool configuration,or does it require factory assembly with extended lead time?

　　We stock popular MB-3 configurations,including 1-spool through 4-spool variants with double-acting spools and manual lever control.Less common configurations—such as motor spools,float-position spools,or electro-hydraulic actuation—are built to order at the factory.Lead time for in-stock configurations is 1–3 business days;factory-built configurations require 4–8 weeks.Contact Beijing Zhongping Technology with your model code to confirm current stock availability.

　　8.What is the warranty period,and what does it cover for the YOULI MB-3?

　　The YOULI MB-3 carries a 1-year warranty against manufacturing defects in materials and workmanship under normal operating conditions per the manufacturer‘s published specifications.Warranty covers valve body defects,spool seizure,and internal leakage exceeding factory specification.It does not cover seal degradation from contaminated hydraulic fluid,operation beyond rated pressure or temperature limits,or wear from abrasive fluid conditions.Extended warranty options are available for fleet purchases.

　　9.Are there interchangeable brands or drop-in replacements for the MB-3,or is it a proprietary design?

　　The YOULI MB-3 has a proprietary monoblock body and port layout.While other manufacturers produce monoblock valves in the 45 L/min class(Brand Hydraulics MB series,for example),the mounting footprint,port spacing,and spool actuation geometry are not standardized across brands.The MB-3 is not a direct drop-in replacement for competitor valves,nor are competitor valves direct replacements for the MB-3—physical and hydraulic interchange must be verified dimensionally before substitution.

　　10.What minimum order quantity is required,and is sample or single-unit ordering available for prototyping?

　　The minimum order quantity is 1 unit.Single-unit ordering is available for prototyping,system testing,and low-volume equipment builds—no minimum quantity restrictions apply to standard configurations.For OEM production volumes with scheduled releases,Beijing Zhongping Technology can structure blanket purchase orders with periodic call-off shipments to manage inventory and cash flow.