Hydraulic pressure relief valve

@PRESSURE_RELIEF_VALVE_DEFINITION {
@PRESSURE_RELIEF_VALVE_NAME {HydPrvlName} {
@HYDRAULIC_DEVICE_MODEL_NAME {HydModl}
@HYDRAULIC_CHAMBER_NAME {HydChmb0Name, HydChmb1Name}
@VALVE_AREA {ValveArea0, ValveArea1}
@MASS_COEFFICIENT {m}
@DAMPING_RATIO {ζ}
@STIFFNESS_COEFFICIENT {k}
@ORIFICE_DISCHARGE_COEFFICIENT {Cd}
@PRELOAD_FORCE {Fp}
@FLOW_AREA_COEFFICIENT {FlowArea0, FlowArea1}
@VALVE_MAXIMUM_DISPLACEMENT {xmax}
@COMMENTS {CommentText}
}
}

Introduction

Figure 1. Configuration of the hydraulic chamber.

The pressure relief valve, shown in fig. 1, is connected to two hydraulic chambers, HydChmb0Name and HydChmb1Name, respectively, with pressures p0 and p1, respectively, and is associated with hydraulic device model, HydModl. It features a poppet of mass m, connected to a spring of stiffness constant k and dashpot of constant c = 2ζ√km; the spring is preloaded with a pre-load force Fp .

The area of the orifice through which oil can flow is evaluated as Aorf = x (FlowArea0 + x FlowArea1), where x is the displacement of the valve, see fig. 1. The net force acting on the valve is evaluated as NetForce = p0 ValveArea0 - p1 ValveArea1 - Fp . If the net force is negative, the valve is locked and condition x = 0 is enforced. If the valve displacement exceeds xmax, condition x = xmax is enforced.

The description and formulation of the hydraulic chamber and elements describes the relationships among these variables.

NOTES

  1. It is possible to attach comments to the definition of the object; these comments have no effect on its definition.

Sensors

Sensors can be defined to extract information about pressure relief valves. The following SensorType specifications are allowed for pressure relief valves: PRESSURE_RELIEF_VALVE_DATA. (Default value: PRESSURE_RELIEF_VALVE_DATA).

No u value and v value are accepted for the hydraulic device.