Special function cartridge valves are:
• 1:0.25 area ratio cartridge for low pressure relief and
• Directional function model CV**-**-C025
This section of the catalog includes circuitry for applying hydrostat functions to flow control throttles, using standard cartridge relief components and control modules.
Cartridge: Sizes 16 to 40
This cartridge arrangement has a 1:0.25 area ratio and operates with a pilot flow entering at X, the pilot flow rate being governed by the integral pressure compensated flow control. Pilot flow passes out of Z1 to an appropriate pilot relief valve which creates pressure on the top of the pilot piston. This means the main valve will open at, and maintain, a pressure at A of 25% of pilot pressure.
When used with an electrohydraulic proportional pressure control (connected to Z1 port), pressures as low as 1,5 bar (22 psi) are controllable at port A, making it ideal for plastics injection molding machine applications. The area ratio of the large piston to sleeve seat is 1:1.1. The Z1 port should never be blocked; doing so could result in pressure intensification at this port. This low pressure relief valve can also be used as a directional control back pressure valve, or as a blocking valve.
When the back pressure function is operational, port Z2 must be drained to the reservoir. The valve can be locked shut by applying at Z2 a pressure greater than any at A.