5.3 Pressure Reducing Valves

NOTE: first 13 entries are REVIEW of pressure control valve family

List the 5 main types of pressure control valves. Draw their associated schematic symbols.

Identify the 5 main characteristics used to classify pressure control valves.

Describe the purpose of a pilot line. Describe the schematic symbol.

Identify pressure control valves that make use of internal pilot lines on their primary, or input, port.

Identify pressure control valves that make use of internal pilot lines on their secondary, or output, port.

Identify pressure control valves that make use of external pilot lines.

Identify pressure control valves that have a NC deactivated state.

Identify pressure control valves that have a NO deactivated state.

Identify pressure control valves that have a check valve bypass. Identify why a check valve bypass is necessary.

Identify pressure control valves that do not have a check valve bypass. Identify why a check valve bypass is not necessary.

Identify pressure control valves that have an internal drain. Identify why an external drain is not necessary.

Identify pressure control valves that have an external drain. Identify why an external drain is necessary. Describe the schematic symbol for an external drain.

Identify customary locations for the 5 main pressure control valves.

Describe a pressure reducing valve using the 5 main characteristics used to classify pressure control valves.

Describe the basic operation of a pressure reducing valve.

Describe how the orientation of the check valve bypass influences this actuator’s action.

Identify functions of the P, R, and D ports for a pressure reducing valve

Differentiate between constant pressure type pressure reducing valves and constant reduction type pressure reducing valves.

Describe operation of this multi actuator hydraulic circuit making use of a pressure reducing valve.

Describe operation of this multi actuator hydraulic circuit making use of both a pressure reducing valve and a sequence valve.

Discuss how set values of the pressure reducing valve, sequence valve, and main pressure relief valve influence the proper functionality of the above system.