Pilot operated, balanced poppet relief valve
Pilot-operated, balanced-poppet 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, smooth, quiet, fast, and have low pressure rise vs. flow.
- Because the modulating occurs inside the cartridge, these valves are immune to most of the problems associated with cavitation, namely noise and manifold erosion.
- Will accept maximum pressure at port 2; suitable for use in cross port relief circuits.
- Valve is relatively insensitive to varying oil temperatures and oil borne contamination.
- Main stage orifice is protected by a 150 micron stainless steel screen.
- Suitable for use in load holding applications.
- Back pressure on the tank port (port 2) is directly additive to the valve setting at a 1:1 ratio.
- 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.
- W and Y controls (where applicable) can be specified with or without a special setting. When no special setting is specified, the valve is adjustable throughout its full range using the W or Y control. When a special setting is specified, this setting represents the maximum setting of the valve.
- Corrosion resistant cartridge valves are intended for use in corrosive environments and are identified by the model code suffix /AP for external stainless steel components, or /LH for external zinc-nickel plated components. See the CONFIGURATION section for all options. For further details, please see the Materials of Construction page located under TECH RESOURCES.
- 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||50 gpm200 L/min.|
|Factory Pressure Settings Established at||4 gpm15 L/min.|
|Maximum Operating Pressure||5000 psi350 bar|
|Response Time - Typical||7 ms7 ms|
|Maximum Valve Leakage at Reseat||10 drops/min.0,7 cc/min.|
|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|
|Adjustment Screw Internal Hex Size||5/32 in.4 mm|
|Locknut Hex Size||9/16 in.15 mm|
|Locknut Torque||80 - 90 lbf in.9 - 10 Nm|
|Model Weight||.50 lb0,25 kg|
|Seal kit - Cartridge||Buna: 990303007|
|Seal kit - Cartridge||EPDM: 990303014|
|Seal kit - Cartridge||Polyurethane: 990303002|
|Seal kit - Cartridge||Viton: 990303006|
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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- 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
- 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