Bi-directional direct-acting relief valve
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.
|Capacity||30 gpm120 L/min.|
|Factory Pressure Settings Established at||4 gpm15 L/min.|
|Maximum Operating Pressure||5000 psi350 bar|
|Maximum Valve Leakage at Reseat||30 drops/min.30 drops/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||1 1/8 in.28,6 mm|
|Valve Installation Torque||45 - 50 lbf ft61 - 68 Nm|
|Seal kit - Cartridge||Buna: 990303007|
|Seal kit - Cartridge||Polyurethane: 990303002|
|Seal kit - Cartridge||Viton: 990303006|
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.
- Get the relief you need. Adjustable. Ventable. Blockable. FLeX-ible.
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- Pressure Equipment Directive 2014/68/EU