SUN Hydraulic Relief Valve RPGS-LAN RPIS-LAN RQEB-LAN RDBA-LWN | Pressure Control Cartridge

The SUN Series Screw-in Cartridge Pressure Relief Valves from Chengyuan Hydraulic are precision-engineered control components designed for high-pressure hydraulic systems. This range is fully compatible with SUN Hydraulics industrial standards, including pilot-operated balanced piston models (RPGS/RPIS), kick-out relief models (RQEB/RQGB/RQIB), and direct-acting models (RDJA/RDBA). Addressing the common industry issue of spool sticking due to installation stress, we strictly implement the floating-construction internal process, ensuring the spool remains flexible within the manifold. Every valve undergoes 100% simulated load testing to verify that pressure adjustment ranges and leakage rates match OEM standards, ensuring 100% original-place interchangeability.

Technical Specifications :

• Pilot-Operated Series: RPGS (45 L/min), RPIS (95 L/min)

• Kick-out Relief Series: RQEB (120 L/min), RQGB (240 L/min), RQIB (480 L/min)

• Direct-Acting Series: RDJA (0.8 L/min), RDBA (95 L/min)

• Max Operating Pressure: 350 bar (5000 psi)

• Adjustment Range (A Version): 100 – 3000 psi (7 – 210 bar)

• Adjustment Options: L (Standard Screw), W (Handknob)

• Seal Materials: Buna-N (Standard) / Viton (Optional)

• Cavity Compatibility: T-10A (Series 1), T-3A (Series 2), T-17A (Series 3), T-19A (Series 4)

Key Technical Advantages:

• Unique Floating Construction: Unlike standard cartridge valves, our SUN-compatible series allows the internal parts to “float” within 0.03-0.05mm. This compensates for manifold machining inaccuracies or excessive installation torque, virtually eliminating the risk of spool sticking.

• Superior Dynamic Response & Stability: The RP series pilot-operated valves feature a balanced piston design, exhibiting extremely low hysteresis and excellent anti-vibration characteristics—ideal for use as main relief valves in heavy-duty machinery.

• Hardened Wear-Resistant Materials: Spools and seats are crafted from premium alloy steel and vacuum-quenched to a hardness of HRC 60-62. Combined with precision grinding, these valves maintain long-term zero-internal-leakage performance even in contaminated fluid environments.

• Reliable Kick-out Functionality: The RQ series quickly switches to a fully open state (unloading) once the set pressure is reached. Chengyuan’s optimized spring-rate distribution ensures accurate switching pressures and reliable resetting.

Application Areas:

• Mobile Machinery: Pilot pressure protection for excavators, pump trucks, and harvesters.

• Industrial Power Units: Main relief or remote pressure regulation for standardized hydraulic power packs.

• Custom Manifolds: Widely used in logic valve blocks and customized integrated manifolds as safety redundancy.

Expert Maintenance Tips:

• Adhere to Installation Torque: Despite the floating design, always use a torque wrench (e.g., 40-50 Nm for T-10A). Excessive torque can damage seals.

• Screw Maintenance: For valves in outdoor environments, periodically apply a small amount of grease to the “L” type adjustment screw and ensure the protective cap is secure.

• Air Bleeding: After replacing a valve, adjust the pressure multiple times at low load to purge air from the pilot chamber, preventing high-frequency noise or chatter.