Walvoil SD5/7-P(KG3-160)/18L/18L/18L/28L/28L/28L/28L/AET is a 7-section monoblock Manual Hydraulic Lever Valve rated at 45 L/min nominal flow and 315 bar maximum pressure with a main relief valve setting of 160 bar.Configured as a 7 Spool Hydraulic Control Valve with four 18 L/min and three 28 L/min spool flow ratings,this unit provides double-acting(DA)spool control with spring-return to neutral and is designed for open-center parallel circuit mobile hydraulic systems in truck-mounted cranes,agricultural machinery,compact construction equipment,and industrial lifting applications.

　　What Is a 7 Spool Hydraulic Control Valve?

　　A 7 spool hydraulic control valve is a directional control valve assembly containing seven individually operated spool sections that direct pressurized hydraulic oil to multiple actuators—typically hydraulic cylinders or motors—from a single inlet supply.Each spool controls one double-acting or single-acting function,allowing a single valve block to manage up to seven independent hydraulic circuits.

　　Monoblock directional control valves integrate all spool sections into a single cast iron body,distinguished from sectional valves that bolt individual sections together with tie rods.The Walvoil SD5/7-P belongs to the monoblock category,offering a compact,heavy-duty design with a 37 mm spool pitch per section and interchangeable 16 mm diameter spools.In mobile equipment applications where space constraints,weight,and cost are driving factors,monoblock multi-spool valves are preferred over sectional alternatives.

　　Key Specifications

　　Total Sections/Spools:7

　　Valve Type:Monoblock directional control valve

　　Circuit Configuration:Open-center parallel circuit with pressure carry-over

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

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

　　Main Relief Valve Setting:160 bar(KG3-160)

　　Maximum Tank Port Back Pressure:25 bar

　　Spool Control Function:Double-acting(DA)on all 7 sections

　　Spool Return Mechanism:Spring-return to neutral(AET designation)

　　Spool Diameter:16 mm,interchangeable

　　Spool Pitch:37 mm

　　Section 1–4 Nominal Flow Rating per Spool:18 L/min

　　Section 5–7 Nominal Flow Rating per Spool:28 L/min

　　Connection Ports(P,A,B,T):G 3/8"BSPP(ISO 228/1)

　　Working Port Location:Front face of valve body

　　Inlet/Outlet Port Location:Front face or side face,selectable

　　Overall Dimensions(L×W×H):323 mm×186 mm×90 mm

　　Mounting Hole Spacing(Length):295 mm

　　Mounting Hole Spacing(Width):73 mm

　　Weight:13.28 kg(with levers,per distributor data)

　　Housing Material:High-strength cast iron

　　Spool Material:Hardened steel

　　Seal Material:NBR(nitrile butadiene rubber)

　　Fluid:Mineral oil,viscosity 46 cSt at 40°C

　　Maximum Fluid Temperature:+80°C

　　Minimum Fluid Temperature:-15°C

　　Recommended Fluid Cleanliness:ISO 4406-/19/16

　　Internal Leakage:Approximately 5 cm³/min(A,B to T at 100 bar)

　　Mounting Orientation:Any position(mount on flat surface)

　　Supplied Accessories:7×control levers included

　　Certifications:Manufacturer facility certified to ISO 9001:2015

　　Technical Highlights

　　Mixed spool flow ratings optimize multi-function machine control.The factory configuration allocates 18 L/min to the first four sections and 28 L/min to the final three,matching actuators with differing flow demands—smaller cylinders for outriggers,stabilizers,or boom swing on the lower-flow sections and higher-flow functions such as boom lift or bucket tilt on the 28 L/min sections.A common procurement question is whether the spool flow distribution is fixed—it is configurable at the point of order,with Walvoil offering 18 L/min and 28 L/min spool options to be specified per section.

　　Pressure carry-over architecture enables simultaneous multi-function operation.The open-center parallel circuit with carry-over(designated by“P”in the model code)allows hydraulic oil to flow through the valve gallery to downstream sections even when an upstream spool is actuated,preventing total flow interruption to later sections.

　　Monoblock cast iron body eliminates inter-section external leakage paths.Unlike sectional valves that rely on tie-rod clamping force and O-ring seals between sections,the one-piece casting inherently removes potential leak points between spool sections.This is particularly relevant for mobile equipment where vibration and thermal cycling accelerate seal degradation in sectional designs.

　　KG3-160 main relief valve provides fixed system pressure protection.The integral,directly-operated relief valve is factory-set at 160 bar,protecting the pump and upstream circuit from over-pressurization.Other pressure ratings within the KG3 family are available for order,with relief settings configurable up to 315 bar to match system requirements.

　　Dual inlet/outlet port positioning simplifies hydraulic plumbing layout.The P and T ports can be routed from either the front face or the side face of the valve body,reducing hose bend radii and allowing the valve to be installed in confined compartments typical of truck-mounted crane pedestals and compact agricultural tractor chassis.

　　Applications

　　Truck-mounted loader cranes:Controls seven independent crane functions—boom lift,boom extension,jib articulation,hook hoist,slew,and dual outrigger pairs—from a single lever bank.The 18 L/min sections allocate appropriate flow to stabilizer cylinders and slew motors,while 28 L/min sections support higher-flow boom lift and extension circuits.

　　Compact construction and earthmoving equipment:Manages multiple hydraulic functions on mini excavators and compact loaders,including boom,arm,bucket,swing,dozer blade,and auxiliary attachment circuits.The open-center parallel architecture allows combined boom-and-arm operation without flow starvation.

　　Agricultural machinery and harvesting equipment:Directs hydraulic flow to header lift,reel speed,auger position,and chute rotation on combine harvesters and forage equipment.Spring-return spools provide automatic neutral return when the operator releases the lever,preventing unintended actuator drift.

　　Municipal and utility service vehicles:Controls refuse compactor blades,tailgate locks,and bin lift mechanisms on waste collection trucks.The monoblock design resists contamination ingress and vibration-induced loosening,maintaining consistent spool feel across extended duty cycles.

　　Industrial lifting and material handling platforms:Operates scissor lift tables,tilt functions,and conveyor positioning on hydraulic work platforms and assembly-line lift stations requiring manual proportional control of multiple hydraulic axes from a centralized operator station.

　　Selection Guidance

　　Suitable applications:

　　Fixed-displacement gear pump systems with flow rates between 25 and 45 L/min—the valve's 45 L/min nominal rating matches the output of standard hydraulic pumps used in compact mobile equipment

　　Machines requiring 5 to 7 double-acting hydraulic functions controlled from a single manual lever station,with spring-return to neutral on every spool

　　Open-center hydraulic circuits where the system operates at 160 bar working pressure or below,with the main relief valve set point protecting the pump during cylinder stall conditions

　　Equipment operators requiring positive mechanical lever feedback and spring-centering action rather than electro-hydraulic joystick control

　　Not recommended for:

　　Closed-center or load-sensing hydraulic systems requiring pressure-compensated flow control on each spool section.Select a load-sensing sectional valve such as the Walvoil DPC130 series,which provides post-compensated flow sharing across sections.

　　Systems demanding spool flow ratings above 28 L/min per section.The SD5 platform supports spool options up to 45 L/min total nominal flow,but individual section flow is limited by the 16 mm spool diameter.For applications requiring 40–80 L/min per function,upgrade to the Walvoil SD8 or SDS180 sectional valve series.

　　Installations where the 160 bar fixed relief valve setting exceeds the maximum allowable system pressure or where adjustable relief settings are required after commissioning.Confirm the KG3 relief valve pressure rating matches the system design pressure at the time of order,as the cartridge is factory-installed and not field-adjustable without component replacement.

　　FAQ

　　1.Can I change the spool flow rating on individual sections—for example,make all seven sections 28 L/min instead of mixed 18L and 28L?

　　Yes.Walvoil SD5 valves are assembled to order and the flow rating of each spool section—18 L/min or 28 L/min—is configurable at the point of manufacture.Specify the required flow per section when placing the order.The spools are field-interchangeable after purchase using standard tools,though this requires depressurizing the system and removing the spool end caps.

　　2.Is the SD5/7-P(KG3-160)with this specific spool configuration in stock,or is it made to order?

　　Distributors commonly stock base configurations such as SD5/2-P and SD5/3-P,but a 7-section unit with four 18L and three 28L spools is a configured assembly.Beijing Zhongping Technology maintains inventory of Walvoil SD5 common configurations and can confirm stock availability or factory lead time for this specific model code within 1 business day of inquiry.

　　3.What is the delivery time if this exact model is not in stock and needs to be built?

　　Factory lead time for configured SD5 monoblock valves is 4 to 6 weeks from order confirmation,subject to production scheduling and the specific spool arrangement.Standard stocked configurations ship within 2 to 5 business days from Beijing Zhongping Technology warehouse.

　　4.Do the control levers come with the valve,and what are the lever mounting options?

　　Seven control levers are supplied with the valve as standard equipment.The lever housing accepts Walvoil SD5/SD6 lever kits with a standard 100 mm lever length.Optional longer levers,rubber boots,and detent kits for float position on individual spools are available separately.

　　5.What are the G 3/8"port connections—are they BSPP,NPT,or SAE,and do I need adapters?

　　All P,A,B,and T ports are G 3/8"BSPP(British Standard Pipe Parallel)threads per ISO 228/1.BSPP ports require a bonded seal or O-ring on the fitting face for leak-free connections.NPT and SAE adapter fittings are not factory-supplied with the valve;source adapters separately if your hydraulic system uses NPT or SAE thread standards.

　　6.The first four spools are 18L and the last three are 28L—can this valve control a hydraulic motor on one of the 28L sections?

　　Yes.The 28 L/min spool sections are suitable for driving fixed-displacement hydraulic motors within their rated flow.For motor applications,confirm that the motor‘s continuous flow demand does not exceed 28 L/min and that the 315 bar maximum pressure rating accommodates the motor’s peak load.The double-acting spool configuration supports bidirectional motor rotation.

　　7.What kind of maintenance does this valve need,and are seal kits available?

　　The monoblock design requires minimal routine maintenance—annual inspection of spool end-cap sealing,lever pivot points,and external port connections.Internal leakage should be monitored;accept approximately 5 cm³/min A/B to T at 100 bar.Seal kits containing NBR O-rings and wiper seals are available from Walvoil distribution channels.Beijing Zhongping Technology supplies genuine Walvoil seal kits and replacement levers.

　　8.If I need a 7-spool valve but with a different relief valve pressure,can you supply that?

　　Yes.The KG3 relief valve is available in multiple pressure ratings.Specify the required pressure setting at the time of order.The relief valve cartridge is factory-installed and tested;field replacement is possible but requires system depressurization and access to the inlet section.Confirm your required relief setting when requesting a quotation.

　　9.Can this SD5 valve be mounted on its side or upside down,or does it need to be installed with levers facing upward?

　　The valve can be mounted in any orientation—horizontal,vertical,or inverted—provided the mounting surface is flat and rigid.Mounting on an uneven surface may distort the cast iron body and cause spool binding.The 295 mm×73 mm mounting hole pattern requires M8 or M10 bolts and flat washers torqued evenly to avoid body stress.

　　10.How does the price of this 7-section configuration compare to buying two smaller valves—for example,a 4-spool plus a 3-spool?

　　A single 7-spool monoblock valve is typically more cost-effective than purchasing and plumbing two separate valves,due to shared inlet and outlet ports,one relief valve instead of two,and reduced hose and fitting labor.For a specific price comparison or formal quotation,contact Beijing Zhongping Technology with your required spool flow distribution and delivery location.