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General Purpose Hydraulic Valves

General-purpose hydraulic valves manage pressure, flow, and circuit protection in industrial fluid power systems, including pressure relief, pressure regulation, flow metering, and check functions. PLC Direct stocks Parker Hannifin PRC series pressure control valves and Vickers DGMFN and DGMX series flow control valves through independent suppliers, available as surplus sealed, refurbished, and used hardware.

Where Are General Purpose Hydraulic Valves Used in Industrial Environments?

General purpose hydraulic valves are installed in virtually every industrial hydraulic system, managing overpressure protection, downstream pressure regulation, and actuator speed control across circuits of all sizes. They appear in centralized hydraulic power units and individual machine circuit subassemblies in any facility that operates fluid power equipment.

Facilities and operations that depend on general-purpose hydraulic valves include:

Metal stamping and press operations, where pressure relief valves protect pump circuits and cylinders from transient overloads generated at the end of each forming stroke.

Plastics injection molding facilities using pressure reducing valves to regulate downstream clamping and injection pressures to specific set points within the machine circuit.

Steel mills and heavy manufacturing equipment where hydraulic flow control valves check flow to maintain actuator speed and prevent cylinder drift under varying load conditions.

Mobile and lifting equipment using check valves to hold cylinder position and prevent unintended load lowering when directional valves are in neutral.

Machine tools and industrial manufacturing facilities where pressure and flow control valves to condition multiple actuator zones within a single hydraulic power unit.

A failed pressure relief valve or a blocked flow control valve causes immediate circuit instability and risks damage to connected hydraulic components, making accurate identification of the replacement essential.

Which Brands of General Purpose Hydraulic Valves Does PLC Direct Stock?

PLC Direct stocks general purpose hydraulic valves from Parker Hannifin and Vickers across three confirmed product families, sourced through independent suppliers.

Parker Hannifin PRC series pilot-operated pressure reducing/relieving valves: Pilot-operated pressure control valves rated to 2,000 PSI with adjustable set points for precise downstream pressure regulation in industrial hydraulic circuits.

Vickers DGMFN series SystemStak flow control valves: Modular needle-type hydraulic flow control valves for subplate-mounted SystemStak assemblies, providing metered flow regulation across the circuit.

Vickers DGMX series SystemStak pressure-compensated flow control valves: Modular valves for SystemStak assemblies requiring actuator speed control that remains consistent independent of load-induced pressure variation.

All listed hardware is available as surplus sealed, refurbished, and used. Contact PLC Direct for part-level availability and current pricing.

What Should You Know Before Ordering General Purpose Hydraulic Valves?

Hardware condition options: Surplus sealed units are unused and in original manufacturer packaging. Refurbished units have been inspected and restored to functional operating condition. Used units are tested and operational, with conditions stated on each product listing.

Compatibility and part identification: General purpose hydraulic valves must be matched by valve type, pressure range, flow rating, port configuration, and mounting interface. For Vickers SystemStak valves, the full model code, including all suffix codes, is required, as suffixes specify mounting orientation, flow direction, and check valve inclusion options.

Warranty: All general purpose hydraulic valve hardware purchased from PLC Direct carries a standard 1-year warranty covering defects and functionality, applicable to surplus sealed, refurbished, and used products. PLC Direct supplies general purpose hydraulic valve hardware for replacement and maintenance and does not provide system design, programming, or integration services.

Frequently Asked Questions

A pressure relief valve is a normally-closed valve that opens when system pressure reaches its set threshold, diverting excess flow to the tank and preventing overload damage to pumps, cylinders, and other circuit components. It is the primary overpressure protection device in industrial hydraulic systems, typically installed at the pump outlet or at individual circuit branches.

A pressure-reducing valve is required when a secondary circuit must operate at a lower, independently controlled pressure than the main pump circuit. For example, when a clamping cylinder must hold at a lower force than a forming cylinder fed from the same pump. Without a reducing valve, both circuits operate at the same pressure, preventing independent force control between actuator zones.

Vickers SystemStak suffix codes define the flow path direction through the valve stack, whether an integral check valve is included, and the port configuration for the subplate assembly. Two SystemStak valves sharing the same base model number but carrying different suffix codes will not function identically in the same manifold position and are not interchangeable; the complete model code, including all suffixes, must be matched exactly.

PLC Direct stocks Parker Hannifin PRC series pilot-operated pressure reducing and relieving valves, and Vickers DGMFN and DGMX series SystemStak flow control valves, through independent suppliers. Contact PLC Direct with a specific part number to confirm current availability across surplus sealed, refurbished, and used condition grades.

Surplus sealed hydraulic pressure valves are unused units that retain their original factory pressure settings, though the set point should be verified against the system's required operating pressure before installation. If adjustment is needed, a calibrated bench test or in-circuit verification should be performed before the valve enters service.