Both relief and pressure-reducing valves affect pressure, but they do different jobs. A relief valve limits pressure in the circuit it protects by opening a path when its setting is reached. A pressure-reducing valve maintains a lower pressure in a downstream branch. One should not be specified in place of the other.
Read where each valve senses pressure
A system relief valve is generally positioned to limit pump or circuit pressure. A reducing valve controls the pressure supplied to a branch such as a clamp or pilot circuit, even when the upstream system operates at a higher pressure. Parker’s pressure-control catalog describes reducing valves for regulating one area of a circuit below normal system pressure. Some reducing/relieving models can also relieve downstream pressure; that behavior is model-specific and should be read from the schematic and data sheet.
Technische Prüfungen
- Mark the pressure that must be limited and the point where it is measured.
- Confirm all downstream components have appropriate pressure ratings.
- Review valve flow capacity, pressure drop and dynamic response.
- Account for trapped-oil thermal expansion and load-induced pressure.
- Provide test points to verify the settings after commissioning.
Häufiger Fehler, den es zu vermeiden gilt
Setting the main relief to a lower value does not create an independently regulated low-pressure branch. It may reduce the performance of every actuator while leaving load-induced local pressure unresolved.
Angaben, die einer Anfrage beizufügen sind
- Circuit schematic with pump and actuator ratings.
- Required system and branch pressures.
- Continuous and transient flow in each branch.
- Required pressure-setting and test procedure.
Specify the valve function and measurement location first, then select a rated product and verify the complete circuit. For related selection guidance, see our HPU RFQ checklist.
Technische Hinweise: Parker hydraulic pressure-control valves; Parker pressure-reducing and relieving valve data. Titelbild: ursprüngliche Konzeptskizze, kein Produktfoto.