Sun's sequence cartridges are similar to relief cartridges except the pilot is separately drained so that valve setting is not affected by pressure in the outlet port. 

Sun sequence cartridges are normally closed pressure control elements designed to modulate flow from port 1 (inlet) to port 2 (outlet) like a relief valve as long as the pressure at port 1 exceeds the pressure setting plus the back pressure at port 3 (the control chamber drain). Unlike relief valves, sequence valves generate a constant pressure at the inlet port irrespective of the pressure on the outlet port.

Sun's sequence valves offer the following:

• Functionally interchangeable with one another (same flow path, same cavity for a given frame size)
• Offered in five sizes with flow rates up to 120 gpm (480 L/min.)
• Fully adjustable over a wide range of operating pressures up to and including 5000 psi (350 bar) (6000 psi (420 bar) intermittent) (except air piloted versions)

A typical application for our sequence valves is when maintained clamping pressure is required in the primary circuit while work is being performed in the secondary circuit.