Package HydraulicsByFluidon.​Components.​Valves.​PressureValves
Icon for standard packages

Information

Standard package icon.

Extends from Modelica.​Icons.​Package (Icon for standard packages).

Package Contents

Model HydraulicsByFluidon.​Components.​Valves.​PressureValves.​PRVstatic

Information

The component PRVstatic is a model of a direct controlled pressure relief valve without dynamic characteristics. For all pressures exceeding Opening pressure the valve opens and the flow increases linearly following the slope given by parameters Nominal volume flow and Nominal pressure difference.

If the valve is balanced (Balanced valve = true) the valve opens when the supply pressure exceeds the opening pressure:

Opening condition: fluidPortA.p > Opening pressure + pAmbient

If the valve is not balanced (Balanced valve = false) the tank pressure is considered:

Opening condition: fluidPortA.p > Opening pressure + fluidPortB.p

If Find exact opening point is set to true, the valve opens exactly at the time when the opening pressure is exceeded. If it is set to false, the valve may open earlier or later depending on simulation's step size. This setting avoids an event (and probably a slow down of simulation) by using noEvent().

The component part PRVstatic is not a model of a pressure relief valve according to its physical structure. It merely represents the characteristic behavior of a pressure relief valve. Therefore dynamic effects such as forces due to inertia will not be represented.

Extends from HydraulicsByFluidon.​Components.​Valves.​Base.​PartialPRV.

Parameters

Connectors

Model HydraulicsByFluidon.​Components.​Valves.​PressureValves.​PropPRVstatic

Information

The component PropPRVstatic is a model of a proportional pressure relief valve without dynamic characteristics. For all pressures exceeding opening pressure the valve opens and the flow increases linearly following the slope given by parameters Nominal volume flow and Nominal pressure difference.

The opening pressure is calculated by Input * Input scaling. If input should be in the range of 0 to 10 [V] and maximum opening pressure 200e5 Pa, Input scaling must be set to 20e5 [Pa/V] (200e5 / 10). If the opening pressure should be given directly by input, Input scaling must be set to 1. Please note: the upper value of opening pressure is not limited but only proportional to input.

If the valve is balanced (Balanced valve = true) the valve opens when the supply pressure exceeds the opening pressure:

Opening condition: fluidPortA.p > opening pressure + pAmbient

If the valve is not balanced (Balanced valve = false) the tank pressure is considered:

Opening condition: fluidPortA.p > opening pressure + fluidPortB.p

If Find exact opening point is set to true, the valve opens exactly at the time when the opening pressure is exceeded. If it is set to false, the valve may open earlier or later depending on simulation's step size. This setting avoids an event (and probably a slow down of simulation) by using noEvent().

The component part PRVstatic is not a model of a pressure relief valve according to its physical structure. It merely represents the characteristic behavior of a pressure relief valve. Therefore dynamic effects such as forces due to inertia will not be represented.

Extends from HydraulicsByFluidon.​Components.​Valves.​Base.​PartialPRV.

Parameters

Connectors

Model HydraulicsByFluidon.​Components.​Valves.​PressureValves.​PressureCompensator

Information

The component PressureCompensator is a partial physical model of a 2-way pressure compensator with signal based dynamics of the spool. The flow characteristic of fully opened valve is given by parameters Nominal volume flow and Nominal pressure difference.

The valve controls a differential pressure between an externally supplied measuring point (port X) and pressure at port B. The controlled pressure difference is given by Differential pressure, the valve dynamics by Response time of valve spool.

Internally a variable resistor is adjusted with (pDifferential - (fluidPortB.p - fluidPortX.p)) * Feedback factor)) as input. Feedback factor is used to influence the accuracy of the pressure compensator.

These valves are used for load pressure independent regulation of flow rates of consumers. In combination with manually actuated or proportional throttle, pressure compensators can be used for the load-independent lifting and lowering of variable loads at the same velocities. They act thereby as pressure compensated flow control valves.

Another typical application are LS-systems where they are used to compensate the influence of different load pressures of several actuators.

Extends from HydraulicsByFluidon.​Components.​Valves.​Base.​PartialPressureFlowValve.

Parameters

Connectors

Model HydraulicsByFluidon.​Components.​Valves.​PressureValves.​CounterBalanceValve

Information

The component CounterBalanceValve is a model of a counterbalance valve (or load control valve) with signal based dynamics of the spool.

The following images show how to determine the parameters of the valve.

The flow characteristic of fully opened valve is given by parameters Nominal volume flow and Nominal pressure difference.

Relief and pilot performance diagram gives the parameters Relief pressure A->B and Relief pressure difference A->B.

Pilot ratio is one the main characteristics of a counter balance valve and is given in the data sheet.

Opening pressure difference B->A is a characteristics parameter of the check valve for reverse flow. It can be determined also from free flow diagram. In the presented diagram the opening pressure difference is very small. Typically, values are around 1 bar.

Counterbalance valves are used with cylinders to safely hold suspended loads and deal with over-running loads. This valve can also be used with hydraulic motors and is then commonly called a brake valve. Both counterbalance valves and pilot-operated check valves can be used to lock fluid in a cylinder to prevent drifting. However, a pilot-operated check valve cannot control an over-running load. Whenever uncontrolled movement can occur from an overrunning load, a counterbalance valve should be used.

Extends from HydraulicsByFluidon.​Components.​Base.​HydTwoPortVerticalExt.

Parameters

Connectors

Model HydraulicsByFluidon.​Components.​Valves.​PressureValves.​PressureReducingValve

Information

The component PressureReducingValve is a model of a 2-port pressure control valve. It maintains a largely constant outlet pressure even at a variable (higher) inlet pressure.

If inlet pressure pA is less than Set pressure (relative value) the valve acts like an orifice with the characteristics Nominal volume flow and Nominal pressure difference.

For all pressures exceeding Set pressure (relative value) the valve opens and the flow increases linearly following the slope given by parameters Nominal volume flow and Pressure drop. The outlet pressure deviates by Deviation P-A @ Nominal volume flow.

The component PressureReducingValve is not a model of a pressure control valve according to its physical structure. It merely represents the characteristic behavior of a pressure reducing valve. Therefore dynamic effects such as forces due to inertia will not be represented.

Extends from HydraulicsByFluidon.​Components.​Valves.​Base.​PartialPressureFlowValve.

Parameters

Connectors

Model HydraulicsByFluidon.​Components.​Valves.​PressureValves.​PressureControlValve

Information

The component PressureControlValve is a model of a 3-port pressure control valve. It maintains a largely constant outlet pressure even at a variable (higher) supply pressure. In addition to a 2-port pressure reducing valve it also reduces the outlet pressure to tank.

If supply pressure pA is less than Set pressure (relative value) the valve acts like an orifice with the characteristics Nominal volume flow and Nominal pressure difference.

For all pressures deviating from Set pressure (relative value) the valve opens and the flow increases linearly following the slope given by parameters Nominal volume flow and Pressure drop. For flow P->A the outlet pressure deviates by Deviation P-A @ Nominal volume flow and by Deviation P-A @ -Nominal volume flow for flow A->T.

The component PressureControlValve is not a model of a pressure control valve according to its physical structure. It merely represents the characteristic behavior of a pressure control valve. Therefore dynamic effects such as forces due to inertia will not be represented.

Extends from HydraulicsByFluidon.​Components.​Valves.​Base.​PartialPressureValve_32.

Parameters

Connectors

Model HydraulicsByFluidon.​Components.​Valves.​PressureValves.​PropPressureControlValve

Information

The component PropPressureControlValve is a model of a 3-port pressure control valve with an input of set pressure. It maintains a largely constant outlet pressure even at a variable (higher) supply pressure. In addition to a 2-port pressure reducing valve it also reduces the outlet pressure to tank.

The set pressure is calculated by Input * Input scaling. If input should be in the range of 0 to 10 [V] and maximum set pressure 200e5 Pa, Input scaling must be set to 20e5 [Pa/V] (200e5 / 10). If the set pressure should be given directly by input, Input scaling must be set to 1. Please note: the upper value of set pressure is not limited but only proportional to input.

If supply pressure pA is less than Set pressure (relative value) the valve acts like an orifice with the characteristics Nominal volume flow and Nominal pressure difference.

For all pressures deviating from Set pressure (relative value) the valve opens and the flow increases linearly following the slope given by parameters Nominal volume flow and Pressure drop. For flow P->A the outlet pressure deviates by Deviation P-A @ Nominal volume flow and by Deviation P-A @ -Nominal volume flow for flow A->T.

The component PressureControlValve is not a model of a pressure control valve according to its physical structure. It merely represents the characteristic behavior of a pressure control valve. Therefore dynamic effects such as forces due to inertia will not be represented.

Extends from HydraulicsByFluidon.​Components.​Valves.​Base.​PartialPressureValve_32.

Parameters

Connectors