Reducing/relieving cartridges add the function of a full-flow pressure relief valve from the reduced pressure port 1 to drain/tank port 3. This feature allows the reduced pressure at port 1 to remain relatively constant under back flow conditions. 

Sun Hydraulics reducing/relieving cartridges are available in both 3- and 4-port versions with flow rates up to 80 gpm (320 L/min) and offer several mounting options.

• Functionally interchangeable with one another (same flow path, same cavity for a given frame size)
• Five sizes, flow rates up to 80 gpm (320 L/min.)
• Fully adjustable up to and including 4500 psi (315 bar) with inlet pressures up to 5000 psi (350 bar) (except air piloted versions)
• Reducing/relieving cartridges are offered in both three- and four-port configurations