Bi-directional, direct-acting relief valve

Capacity: 25 gpm95 L/min. | Cavity: T-10A
RBDA : Bi-directional, direct-acting relief valve
Technical Features [ + ]

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.

  • Capacity from port 1 to port 2 is 25 GPM (95 L/min). Flow from port 2 to port 1 is rated at 10 GPM (40 L/min).
  • Recommended minimum setting is 1200 psi (85 bar). Note: At settings below 1200 psi (85 bar), the valve is rated for maximum transient flows of 25 GPM (95 L/min) only.
  • 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 system pressure which means this valve can only be adjusted when the pressure is removed. The setting procedure 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.
  • 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.
Technical Data [ + ]
Note: Data may vary by configuration. See CONFIGURATION section.
Cavity T-10A
Series 1
Capacity 25 gpm95 L/min.
Maximum Operating Pressure 5000 psi350 bar
Factory Pressure Settings Established at 4 gpm15 L/min.
Maximum Valve Leakage at Reseat 10 drops/min.0,7 cc/min.
Response Time - Typical 2 ms2 ms
Reseat >85% of setting>85% of setting
Hysteresis ≤ 3 %≤ 3 %
Adjustment - No. of CW Turns from Min. to Max. setting 55
Valve Hex Size 7/8 in.22,2 mm
Valve Installation Torque 30 - 35 lbf ft41 - 47 Nm
Model Weight .40 lb0,20 kg
U.S. Patent # 11,384,85711,384,857
Seal kit - Cartridge Buna: 990310007
Seal kit - Cartridge Viton: 990310006
Performance Curves [ + ]
FAQs [ + ]

Pressure setting tolerances are listed in our Performance Data page. A link to this page can also be found in the Additional Resources tab of the applicable product page.

There are exactly 250 Sun drops in a cubic inch or 15 in a cc.

Maybe not. We build in a good amount of overlap in the kick-down reliefs to prevent false tripping. This means they are not as fast as our standard pilot-operated reliefs. A direct-acting relief valve set just above the kick-down relief valve would be good insurance.

Direct-acting valves are used to prevent over pressure, and pilot-operated valves are used to regulate pressure. If you are unsure, use a direct-acting valve. Sun's direct acting valves are very fast, dirt tolerant, stable, and robust. Sun's pilot-operated valves are moderately fast, they have a low pressure rise vs. flow curve, and they are easy to adjust.

One graphic example is on a portable grain auger for silos. When the farmer gets caught in the auger the kick-down relief trips and allows him to escape.

Only external seals are serviceable.  Sun offers replacement seal kits for all cartridge models. The applicable kit part number can be found in the product page's Technical Data table or by using our Cartridge Seal Kit search function located under Accessories. Please note: Converting the external seals from one material to another does not ensure fluid compatibility with that material due to the existence of internal seals within the cartridge.
Additional Resources [ + ]