Pilot-operated, balanced piston relief valve
Pilot-operated, balanced-piston relief cartridges are normally closed pressure regulating valves. When the pressure at the inlet (port 1) reaches the valve setting, the valve starts to open to tank (port 2), throttling flow to regulate the pressure. These valves are accurate, have low pressure rise vs. flow, they are smooth and quiet, and are moderately fast.
- All 2-port relief cartridges (except pilot reliefs) are physically and functionally interchangeable (same flow path, same cavity for a given frame size).
- Will accept maximum pressure at port 2; suitable for use in cross port relief circuits. If used in cross port relief circuits, consider spool leakage.
- Minimum setting is 75 psi (5 bar) for all spring ranges.
- Not suitable for use in load holding applications due to spool leakage.
- Back pressure on the tank port (port 2) is directly additive to the valve setting at a 1:1 ratio.
- The main stage orifice is protected against contamination.
- Cartridges configured with EPDM seals are for use in systems with phosphate ester fluids. Exposure to petroleum based fluids, greases and lubricants will damage the seals.
- 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||12 gpm45 L/min.|
|Factory Pressure Settings Established at||4 gpm15 L/min.|
|Maximum Operating Pressure||5000 psi350 bar|
|Maximum Valve Leakage at 110 SUS (24 cSt)||2 in³/min.@1000 psi30 cc/min.@70 bar|
|Response Time - Typical||10 ms10 ms|
|Adjustment - No. of CW Turns from Min. to Max. setting||55|
|Valve Hex Size||3/4 in.19,1 mm|
|Valve Installation Torque||20 - 25 lbf ft27 - 33 Nm|
|Adjustment Screw Internal Hex Size||5/32 in.4 mm|
|Locknut Hex Size||1/2 in.12,7 mm|
|Locknut Torque||80 - 90 lbf in.9 - 10 Nm|
|Model Weight||.20 lb0,10 kg|
|Seal kit - Cartridge||Buna: 990162007|
|Seal kit - Cartridge||EPDM: 990162014|
|Seal kit - Cartridge||Polyurethane: 990162002|
|Seal kit - Cartridge||Viton: 990162006|
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.
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.
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- 'Soft' Relief Eliminates Pressure Spikes
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- QuickDesign with SmartConnect Offers Drag-and-Drop Schematic Tool
- Units of Measure, Settings, and Conversions
- Cavity Information (S-171) and Tooling
- Sun Model Code Explanation; 999-901-334 (343.9 KB)
- Cartridges: Materials of Construction
- Fluid Recommendations: Oil Viscosity, Cleanliness & Temperature
- Performance Data
- Sun's Floating Style Screw-In Cartridge (1.06 MB)
- Pressure Equipment Directive 2014/68/EU