DFY-B20H2-S Hydraulic Pilot Check Valve 31.5MPa

Product Overview

Models such as DFY-B20H2-S, DFY-B32H2-S, DFY-F50H1-S and DFY-F50H2-S belong to the DFY series of hydraulic pilot-operated check valves. Featuring a seat-type design for leak-free locking, they allow free flow in one direction and provide reliable pilot-pressure unlocking in the reverse direction. Every unit undergoes rigorous 100% simulated operating-condition testing and offers excellent drop-in interchangeability with equivalent pilot check valves. Reliable load-holding and controlled release functions make them ideal for medium-to-high-pressure hydraulic systems requiring safe actuator locking.

Technical Specifications 

• Model examples: DFY-B20H2-S, DFY-B32H2-S, DFY-F50H1-S, DFY-F50H2-S
• Valve type: Pilot-operated check valve (seat type)
• Nominal size: B20 / B32 / F50 (different flow ratings)
• Maximum operating pressure: typically 21–31.5 MPa (depending on H1/H2 pressure class)
• Actuation: Hydraulic pilot unlocking
• Function: Free flow in one direction, leak-free locking in reverse, pilot pressure opens reverse flow
• Mounting: Subplate or in-line (depending on model)
• Seal material: NBR or FKM (fluid dependent)
• Typical pressure rating: H1 / H2

Key Technical Advantages

1. Seat-type leak-free locking: Hardened seat design achieves true zero leakage, reliably holding loads even after prolonged periods under pressure for high safety.
2. Reliable pilot unlocking: Hydraulic pilot design ensures smooth opening of reverse flow and reduces hydraulic shock.
3. Excellent drop-in interchangeability: Dimensions and interfaces follow industry-common standards, allowing direct replacement of equivalent pilot check valves and minimizing modification costs and downtime.
4. High-pressure capability: Suitable for medium-to-high-pressure systems with compact structure and flexible installation.
5. Precision machining and long service life: High-strength body and hardened internal components provide strong contamination resistance and long-term reliability.

Application Areas

Injection moulding machines, die-casting machines, metal-forming equipment, lifting platforms, mobile machinery, machine-tool hydraulics, marine hydraulics and other medium-to-high-pressure circuits requiring safe load holding.

Expert Maintenance Tips

1. Ensure interfaces are clean and seals are intact before installation; tighten to the recommended torque to prevent external leakage.
2. Maintain recommended fluid cleanliness; use hydraulic fluids compatible with the installed seal material. Check the pilot oil circuit before first start-up.
3. Ensure sufficient pilot pressure to overcome main-line pressure for reliable unlocking; periodically inspect for external leakage.
4. Clean and protect sealing surfaces during long-term storage; perform functional and sealing tests before recommissioning.
5. Do not disassemble seat and pilot components. Seal replacement or repairs should be performed only by experienced technicians.