Product Overview
The MRP-01-C-30 is a modular (sandwich) pressure reducing valve from YUKEN’s MRP series, specifically designed for P-line (inlet line) applications. Featuring modular (sandwich) mounting with interface conforming to ISO 4401-AB-03-4-A, this valve is sized NG6 (series 01) .
The MRP series modular pressure reducing valves consist of a high-strength cast iron body with precision-machined spool and pilot valve components. The core function is to precisely reduce the primary-side high pressure of the P-line (inlet line) to a stable, lower secondary-side pressure through the coordinated action of the built-in pilot valve and main spool—maintaining constant secondary pressure regardless of primary pressure fluctuations or flow variations. For pressure adjustment, loosen the lock nut and turn the adjustment screw clockwise to increase pressure or counterclockwise to decrease pressure; be sure to re-tighten the lock nut firmly after adjustment.
Model Code – Pressure Adjustment Range:
MRP-01-B-30: Adjustment range * ~ 7 MPa (refer to min. adjustment pressure characteristics & max. flow)
MRP-01-C-30: Adjustment range 3.5 ~ 14 MPa
MRP-01-H-30: Adjustment range 7 ~ 21 MPa
As a direct replacement solution for the YUKEN MRP series, this product strictly complies with YUKEN modular valve technical standards and offers complete interchangeability—direct drop-in replacement without any modification to mounting dimensions or piping connections. Every unit undergoes 100% simulated duty cycle testing prior to shipment, ensuring performance reliability and long-term operational stability under actual working conditions.
Technical Specifications
MRP-01-C-30 (P-Line Modular Pressure Reducing Valve)
Model: MRP-01-C-30
Series: MRP (Pressure Reducing Valve for P-Line)
Brand: YUKEN
Valve Size: 01 (NG6 / 6 mm port size)
Mounting Type: Modular / Sandwich Mounting
Mounting Interface Standard: ISO 4401-AB-03-4-A
Maximum Operating Pressure: 31.5 MPa (315 bar / 4570 psi)
Maximum Flow Rate: 35 L/min
Pressure Adjustment Range (Type C) : 3.5 ~ 14 MPa
Pressure Adjustment Range (Type B) : * ~ 7 MPa (refer to min. adj. pressure characteristics)
Pressure Adjustment Range (Type H) : 7 ~ 21 MPa
Nominal Bore: 1/8 inch
Fluid Media: Hydraulic oil
Fluid Viscosity: 35 mm²/s
Fluid Specific Gravity: 0.850
Operating Temperature Range: Max. 80 °C
Body Material: Cast iron
Connection Type: Subplate / Modular
Weight: Approx. 1.3 – 1.5 kg
Design Number: 30
Key Technical Advantages
1. Modular Pipe-Free Connection – High System Integration
The MRP series features modular (sandwich) mounting, where valves are stacked directly between the directional valve and subplate using tie bolts—eliminating all piping connections. This design significantly reduces potential leak points, eliminates vibration and noise from pipe connections, and dramatically shortens system design, assembly, and maintenance cycles. The standardization and interchangeability of modular valve systems allow for quick and convenient reconfiguration when system functions need to be added or modified.
2. P-Line Dedicated Pressure Reduction – Versatile Pressure Solutions
The MRP series is specifically designed for P-line (inlet line) applications, ideal for hydraulic systems requiring stable secondary-side pressure supply from the P-line. With three pressure adjustment ranges (B, C, H), the series covers a wide spectrum from low pressure (~7 MPa) to medium-high pressure (7–21 MPa).
3. Precision Cast Iron Body & Machining – Long-Term Reliability
The valve body is manufactured from high-strength cast iron, with all bores and mounting surfaces precision-machined in a single setup to ensure micron-level fit tolerances between spool and body. Cast iron provides excellent vibration damping and dimensional stability, resisting deformation under long-term high-pressure operation and ensuring extended service life.
4. Intuitive Manual Adjustment & Locking Mechanism
Equipped with an adjustment screw and lock nut mechanism, on-site pressure setting is intuitive and convenient. Each rotation of the adjustment screw delivers a predictable pressure change, allowing operators to make adjustments without special tools. The lock nut effectively prevents pressure drift caused by vibration, ensuring long-term operational stability.
5. Wide Flow Adaptability & Stable Pressure Regulation
The MRP-01 series maintains stable pressure reduction characteristics across the full 35 L/min flow range. Note that when the pressure setting is below 1.9 MPa, the maximum available flow is limited. The minimum adjustment pressure equals the minimum adjustment pressure characteristic value plus the tank line back pressure of this valve—this back pressure should include the T-line pressure drop characteristics of all valves stacked on the base side. This engineering detail ensures accurate pressure setting in multi-valve stacked systems.
6. Broad Industry Application & Proven Reliability
YUKEN modular valves are widely used in construction machinery, environmental sanitation equipment, CNC machine tools, automated marine systems, and steel mill equipment. As a classic product in the YUKEN portfolio, the MRP series has earned industry-wide recognition for its reliability, stability, and interchangeability over decades of field service.
Application Areas
Injection Molding Machinery: Providing stable low-pressure oil supply for pilot control circuits
CNC Machine Tool Hydraulic Systems: Precision pressure reduction for clamping, tool change, and auxiliary functions
Construction Machinery Hydraulic Systems: Stable pilot pressure supply for implement control circuits
Metallurgical & Mining Equipment: Multi-stage pressure regulation for rolling mills, lift platforms, and related equipment
Marine Hydraulic Systems: Stable pressure reduction for steering gear, windlass, and control circuits
Automated Production Line Hydraulic Systems: Differentiated pressure supply for multi-station hydraulic actuators
Steel Mill Hydraulic Systems: Precision pressure control for continuous casting, rolling, and process equipment
Expert Maintenance Tips
1. Modular Valve Assembly Sequence & Mounting Surface Verification
When assembling modular valves, position the side with O-rings facing the subplate (base plate). Before inserting the tie bolts, verify that all valve port positions are correctly aligned and that the bolt holes are properly aligned across all stacked valves. All valves in a stacked assembly must be of the same nominal size (NG6) .
2. Hydraulic Fluid Cleanliness Control
The MRP series features精密 clearances between the spool and body, making it sensitive to fluid contamination. Maintain system fluid cleanliness at ISO 4406 16/13 (or NAS 1638 Class 8) or better, with a suction or return-line filter of no less than 10 μm absolute.
3. Pressure Setting Procedure
To adjust pressure: loosen the lock nut, then turn the adjustment screw clockwise to increase pressure or counterclockwise to decrease pressure. Final calibration should be performed under actual system operating flow conditions and verified 2–3 times to ensure accuracy. Re-tighten the lock nut firmly after adjustment.
4. Minimum Adjustment Pressure & Back Pressure Considerations
The minimum adjustment pressure equals the sum of the minimum adjustment pressure characteristic value and the tank line back pressure. This back pressure should include the T-line pressure drop of all valves stacked on the base side. In multi-valve stacked systems, ensure adequate return line sizing to prevent excessive T-port back pressure that could elevate the set pressure.
5. Scheduled Maintenance
Perform preventive maintenance every 2,000 operating hours or every six months:
Inspect adjustment screw and lock nut for loosening
Inspect O-ring seals for aging, hardening, or damage (replace seals after every disassembly)
Verify tie bolt torque meets specifications (tighten in diagonal sequence over multiple passes)
If secondary pressure becomes unstable, response becomes sluggish, or pressure drift occurs, promptly check fluid cleanliness and clean or replace the spool assembly as necessary
