Walvoil SD5/5-P(KG3-160)/18L/18L/18L/18L/18L/AET is a 5-spool Monoblock Directional Control Valve for open-center hydraulic circuits.This 5 spool hydraulic control valve delivers 45 L/min nominal flow and operates at 315 bar maximum pressure per manufacturer datasheet,controlling up to five independent double-acting cylinders or hydraulic motors in metallurgical hydraulic systems,marine hydraulic systems,construction equipment,and mobile hydraulic applications.

　　What Is a Monoblock Directional Control Valve?

　　A Monoblock Directional Control Valve is a hydraulic component that directs pressurized fluid flow to multiple actuators within a single,integrated cast-iron body.Unlike sectional valves assembled from individual modules,a monoblock design eliminates external interfaces between sections,reducing potential leak paths and simplifying mounting to a single-plane surface.The spool within each section shifts to route oil from the pump inlet port(P)to either work port A or B,while returning exhaust fluid to the tank port(T).

　　Monoblock valves are categorized by circuit configuration—open-center,closed-center,parallel,series,or tandem—and by the number of spools,which determines how many independent actuators can be controlled from a single valve assembly.The Walvoil SD5 series occupies the medium-flow segment of the manufacturer‘s portfolio,positioned between the SD4 compact valve and the SD18 high-flow valve,and is available in configurations from one to seven spools per valve body.

　　Key Specifications

　　Number of Spools:5

　　Valve Type:Monoblock Directional Control Valve

　　Circuit Configuration:Open-center parallel circuit(P-type)

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

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

　　Maximum Operating Pressure(Series Circuit):250 bar(3,625 psi)per manufacturer datasheet

　　Maximum Back Pressure(Port T):25 bar(360 psi)per manufacturer datasheet

　　Maximum Return Pressure:25 bar per manufacturer datasheet

　　Spool Configuration:18L(double-acting,spring-return to neutral,A and B closed in neutral)

　　Control Type:Manual lever with spring return

　　Pilot Control Options:Hydraulic,electro-hydraulic,pneumatic,electro-pneumatic,or cable(Bowden)control available per manufacturer datasheet

　　Main Relief Valve Setting(KG3-160):160 bar(2,320 psi)per manufacturer datasheet

　　Work Port Size:G 3/8"BSPP(British Standard Pipe Parallel)per manufacturer datasheet

　　Inlet/Outlet Port Configuration:Side inlet and side outlet

　　Mounting Type:Through-bolt mounting on flat surface

　　Mounting Orientation:Any orientation

　　Number of Sections:1 to 7 per valve body per manufacturer datasheet

　　Section Pitch:37 mm(1.46 in)per manufacturer datasheet

　　Fluid Type:Mineral oil,viscosity 46 cSt at 40°C per manufacturer datasheet

　　Fluid Cleanliness:ISO 4406 20/18/15 or better

　　Operating Temperature Range:-20°C to+80°C

　　Operating Ambient Temperature Range:-40°C to+60°C

　　Internal Leakage(A/B to T):15 cm³/min at 120 bar and 40°C fluid temperature per manufacturer datasheet

　　Body Material:High-strength cast iron

　　Spool Material:Hardened steel

　　Weight:Approximately 5.5 kg(12.1 lb)estimated based on 5-spool configuration

　　Ingress Protection Rating:IP65 per manufacturer datasheet

　　Certifications:ISO 9001 manufacturing facility

　　Compliance:CE marking

　　Compatible Hydraulic Pumps:Walvoil gear pumps and piston pumps

　　Technical Highlights

　　The KG3-160 designation indicates a main relief valve setting of 160 bar.This factory-preset pressure protects the hydraulic system from over-pressurization by diverting excess flow to the tank port when system pressure exceeds 160 bar.The relief valve is integrated into the inlet section and operates independently of spool position,ensuring continuous protection regardless of which actuators are active.For applications requiring alternative pressure settings,Walvoil offers KG3 relief valves calibrated to 120 bar,200 bar,or 250 bar as standard options per manufacturer datasheet.

　　The 18L spool code defines a double-acting configuration with spring return to neutral and closed work ports(A and B blocked)in the neutral position.This spool type holds the load stationary when the lever is released and prevents cylinder drift under gravitational load.Each of the five spools operates independently,allowing simultaneous or sequential control of up to five hydraulic actuators without cross-interference.For applications requiring different spool characteristics—such as motor spools with open A and B to tank in neutral for free-wheeling hydraulic motors—Walvoil provides interchangeable spools that can be field-replaced without removing the valve body per manufacturer datasheet.

　　The AET suffix denotes a valve configured with manual lever control,side inlet/outlet port arrangement,and spring-return spool actuation.The“A”indicates side inlet and side outlet ports,which simplifies hydraulic plumbing by allowing hoses to approach the valve from a single direction and reduces the overall envelope required for installation.The“E”designates spring return to neutral as the standard control action,while the“T”confirms the valve includes a main relief valve and load check valve on each working section per manufacturer datasheet.

　　The open-center parallel circuit design enables simultaneous operation of multiple actuators at proportionally reduced flow rates.When all spools are in neutral,pump flow circulates freely from inlet port P to tank port T with minimal pressure drop,reducing heat generation and energy consumption during idle periods.When multiple spools are actuated simultaneously,available pump flow divides between active sections—an important consideration for applications requiring coordinated movement of multiple cylinders at full speed.The measured pressure drop from inlet to work port is 10 bar at 45 L/min with one section actuated,and increases to 14 bar with three sections actuated per manufacturer performance data.

　　Applications

　　Metallurgical hydraulic systems:Controls clamping cylinders,ejection rams,and cooling bed actuators in steel mill and foundry auxiliary equipment.The 160 bar relief valve setting protects downstream components from pressure spikes common in high-inertia material handling systems.

　　Marine hydraulic systems:Operates hatch covers,steering gear,stabilizer fins,anchor windlasses,and deck machinery on commercial vessels and offshore platforms.The monoblock cast iron body with IP65 protection rating resists corrosion in saltwater environments when properly coated per marine industry practice.

　　Construction equipment hydraulic systems:Directs flow to outrigger cylinders,boom extension rams,and auxiliary attachments on truck-mounted cranes and aerial work platforms.The five-spool configuration supports full machine functionality without requiring multiple separate valves.

　　Mobile hydraulic equipment:Manages multiple hydraulic functions on agricultural machinery including baling machines,harvesters,and front loaders where space constraints and weight reduction are critical design priorities.

　　Material handling equipment:Controls lift cylinders,tilt mechanisms,and side-shift functions on small forklifts and pallet stackers requiring coordinated multi-axis movement.

　　Industrial automation systems:Serves as the central directional control hub for hydraulic power units in automated production lines,providing discrete cylinder actuation for clamping fixtures and press operations.

　　Selection Guidance

　　Suitable applications:

　　Systems operating with 45 L/min pump flow or less and requiring control of two to five double-acting cylinders or bidirectional hydraulic motors

　　Open-center hydraulic circuits where pump flow circulates to tank at low pressure when no functions are active

　　Applications using mineral oil with viscosity of 46 cSt at 40°C per manufacturer specifications

　　Installations where a 160 bar maximum system pressure meets operational requirements and provides adequate safety margin for connected components

　　Machinery requiring IP65-rated components for protection against dust ingress and low-pressure water jets

　　Not recommended for:

　　Closed-center or load-sensing hydraulic systems.The SD5 series is primarily designed for open-center circuits.For closed-center applications,select a Walvoil valve configured for closed-center operation or consider the SDS series sectional valves with load-sensing capability.

　　Pump flows exceeding 45 L/min.Operating the valve above its nominal flow rating increases pressure drop across the spool lands,generating excessive heat and potentially causing erratic actuator movement.For flow rates between 45 and 160 L/min,select the Walvoil SD18 series instead per manufacturer specifications.

　　Systems requiring relief valve settings above 160 bar without component replacement.The KG3-160 designation indicates a factory-preset 160 bar relief valve.Higher pressure applications require a different KG3 relief valve cartridge rated to 200 bar or 250 bar per manufacturer datasheet.

　　Applications with fluid viscosity outside the 15 to 100 cSt operating range.Fluids with viscosity below 15 cSt may cause excessive internal leakage and reduced volumetric efficiency,while fluids above 100 cSt increase pressure drop and slow spool response.

　　FAQ

　　1.What are the dimensions and port sizes of the SD5/5-P(KG3-160)valve?

　　The 5-spool valve measures approximately 185 mm in width based on 37 mm section pitch,with all work ports(A and B)and inlet/outlet ports(P and T)utilizing G 3/8“BSPP parallel threads per manufacturer datasheet.We provide dimensional drawings and port layout diagrams upon request for installation planning.

　　2.What is the delivery time or lead time for the Walvoil SD5/5-P(KG3-160)?

　　We dispatch stock orders within 1 to 3 business days.For custom spool configurations or non-stock relief valve pressure settings,standard manufacturer lead time is 4 to 6 weeks from order confirmation.

　　3.Is the SD5/5-P(KG3-160)in stock and available for shipment?

　　We maintain inventory of standard-configuration SD5 valves for immediate fulfillment.We recommend confirming current availability for this specific five-spool configuration with 160 bar relief valve setting before placing a purchase order.

　　4.What does the part number SD5/5-P(KG3-160)/18L/18L/18L/18L/18L/AET mean?

　　SD5 identifies the valve series./5 indicates five spools.-P specifies open-center parallel circuit.(KG3-160)denotes the main relief valve type and 160 bar pressure setting./18L repeated five times defines the spool type for each section—18L is a double-acting spool with spring return and closed work ports in neutral./AET indicates manual lever control(A),side inlet/outlet ports(E),and spring return to neutral(T).

　　5.Can the spools in the SD5/5-P(KG3-160)be changed in the field?

　　Yes.Walvoil SD5 spools are field-interchangeable without removing the valve body from the mounting surface.We stock replacement spools with different center conditions—including motor spools(open A and B to tank in neutral),single-acting spools,and float-position spools—and can supply them with installation instructions per manufacturer specifications.

　　6.What is the return policy and warranty period for Walvoil SD5 valves?

　　We provide a 12-month warranty against manufacturing defects from the date of shipment.Beijing Zhongping Technology processes return merchandise authorization(RMA)requests within 48 business hours of receipt,subject to inspection confirming the valve is unused and in original packaging.

　　7.What hydraulic oil viscosity and cleanliness level are required for the SD5/5-P(KG3-160)?

　　The valve operates with mineral oil at 46 cSt viscosity at 40°C per manufacturer datasheet,with an allowable viscosity range of 15 to 100 cSt.The fluid must meet ISO 4406 cleanliness code 20/18/15 or better to prevent spool binding and excessive wear of the hardened steel spools within the cast iron body.

　　8.How much does the SD5/5-P(KG3-160)cost?What is the price range?

　　The SD5/5-P(KG3-160)with five 18L spools and AET configuration typically ranges from$850 to$1,250 USD depending on quantity and customization requirements.Prices fluctuate due to exchange rates,import tariffs,and factory adjustments.For an accurate quotation with current pricing and shipping costs,contact Beijing Zhongping Technology directly.

　　9.Can the SD5/5-P(KG3-160)be used with electro-hydraulic proportional controls?

　　Yes.Walvoil offers electro-hydraulic proportional control kits that mount directly to the SD5 valve body in place of manual levers.These kits provide variable flow control proportional to electrical input signal,enabling joystick operation and remote actuation.Beijing Zhongping Technology can supply the valve configured with proportional controls as a factory-built assembly per manufacturer specifications.

　　10.What are the maintenance requirements and spare parts availability for the SD5/5-P(KG3-160)?

　　Routine maintenance consists of annual external inspection for leakage and verification of relief valve pressure setting.We stock seal kits,replacement relief valve cartridges,lever assemblies,and individual spools for same-day shipment.Beijing Zhongping Technology maintains inventory of all serviceable components for the SD5 series to support ongoing maintenance requirements per manufacturer specifications.