SUN HYDRAULICS CORP
RBFALWN
Pressure Control

The bi-directional, direct-acting relief cartridge is a normally closed, pressure-limiting valve used to protect hydraulic components from pressure transients. When the pressure differential between ports 1 and 2 exceeds the valve setting, the valve starts to open, throttling flow to limit the pressure rise, regardless of the direction.Both directions have very similar setting and performance.

• Because the modulating occurs inside the cartridge, these valves are immune to most of the problems associated with cavitation, namely noise and manifold erosion.
• The seals on the adjust screw are exposed to pressure at port 1 which means this valve can only be adjusted when the pressure is removed or port 2 is used to set the valve. The setting procedure at port 1 is; check the setting, remove the pressure, adjust the valve, check the new setting.
• Valve is relatively insensitive to varying oil temperatures and oil borne contamination.
• Select a spring range where the desired relief setting is approximately mid-range to high between the minimum and maximum pressure to ensure maximum valve repeatability.
• All 2-port relief cartridges (except pilot reliefs) are physically and functionally interchangeable (same flow path, same cavity for a given frame size).
• Incorporates the Sun floating style construction to minimize the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge machining variations.

Additional Resources

• CE/TÜV Certified Pressure Relief Valves
• Pressure Relief and Regulating Cartridge Valve Technical Tips
• Pilot Operated, Balanced Poppet Relief Valves
• Sun Expands Corrosion-Resistant Solutions
• Sun Offers Zinc-Nickel Plating for Corrosion Resistance
• Sun Cartridges with EPDM Seals
• Series 4 PLUS Cartridges Offer Higher Flows with Lower Pressure Losses
• Pilot-Operated, Balanced Poppet, Anti Shock Reliefs
• CavitySaver multi-function valves deliver single-cartridge solutions
• 'Soft' Relief Eliminates Pressure Spikes
• Tri-Grip Handknob Now Offered From Sun as a Standard Control Option
• QuickDesign with SmartConnect Offers Drag-and-Drop Schematic Tool
• Sun Introduces 'Hybrid' Valves
• Manufacturing Sun Cartridge Cavities
• Pressure Relief and Regulating Valves
• Sun Model Code Explanation; 999-901-334
• Cartridges: Materials of Construction
• Fluid and Temperature Recommendations
• Performance Data
• Sun's Floating Style Screw-In Cartridge
• Units of Measure, Settings, and Conversions
• Cavity Information (S-171) and Tooling