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Sun Hydraulics PR*B Direct Acting Reducing/Relieving Cartridges - Three Port

Direct-acting, pressure reducing/relieving valves reduce a high primary pressure at the inlet (port 2) to a constant reduced pressure at port 1, with a full-flow relief function from port 1 to tank (port 3). These valves incorporate a damped construction for stable operation allowing the use of high reduced pressure.


  • Damped construction for exceptionally stable operation.
  • There is no pilot flow from the drain port, making these valves suitable for use in accumulator circuits where they help reduce secondary circuit leakage.
  • Direct operated reducing/relieving valves offer superior dynamic response compared to pilot operated versions.
  • They have low sensitivity to varying oil temperature and oilborne contamination.
  • Exceptional hot oil stability (no oscillation), and reliable cold oil closing.
  • Rugged, robust construction withstands high pressure shocks and back pressure.
  • The pressure override curve is steeper than pilot operated versions.
  • This valve has relieving capability and can be used in a deadheaded application.
  • These direct acting valves exhibit a transitional step, unlike pilot operated versions, between reducing and relieving modes. (This step is equal to 5% of the maximum pressure of the adjustment range, independent of the actual pressure setting. Note that this characteristic may make these valves unsuitable in counterbalancing applications.) Consider PR*C direct acting or PP*B pilot operated reducing/relieving valves if this transitional step could be an application problem.
Part Number Cavity Size Flow Capacity (l/min) Pressure Adjustment Range (bar) Datasheet Link
PRDB-LWN T-11A 40 50-315 View Datasheet Buy Now
PRDB-LDN T-11A 40 1,7-55 View Datasheet Buy Now
PRFB-LWN T-2A 80 50-315 View Datasheet Buy Now
PRHB-LWN T-17A 160 50-315 View Datasheet Buy Now
PRJB-LWN T-19A 320 50-315 View Datasheet Buy Now

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