CounterBalanceValve
Library
HydraulicsByFluidon/Components/Valves/PressureValves
Description
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.
Parameters
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo_pA | pA | pA | Structure | |
mo_pA/fixed | fixed | Cell of scalars | true | |
mo_pA/start | start | Cell of scalars | ||
mo_pB | pB | pB | Structure | |
mo_pB/fixed | fixed | Cell of scalars | true | |
mo_pB/start | start | Cell of scalars | ||
mo_dU | dU | dU | Structure | |
mo_dU/fixed | fixed | Cell of scalars | true | |
mo_dU/start | start | Cell of scalars | ||
mo_NominalVolumeFlow | NominalVolumeFlow | Nominal volume flow | Scalar | |
mo_NominalPressureDifference | NominalPressureDifference | Nominal pressure difference | Scalar | |
mo_ReferenceDensity | ReferenceDensity | Reference density for volume flow and pressure difference | Scalar | |
mo_ReliefPressure | ReliefPressure | Relief pressure A->B | Scalar | |
mo_ReliefPressureDifference | ReliefPressureDifference | Relief pressure difference A->B | Scalar | |
mo_OpeningPressure | OpeningPressure | Opening pressure difference B->A | Scalar | |
mo_pilotRatio | pilotRatio | Pilot ratio | Scalar | |
mo_timeConstant | timeConstant | Response time of valve spool | Scalar | |
mo_deadVolume | deadVolume | Dead volume at ports | Scalar | |
mo_enableStrokeOutput | enableStrokeOutput | Enable spool stroke output | Number | 0 |
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo_forwardFluidProperties | forwardFluidProperties | Forward fluid properties between ports | Scalar | true |
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
mo__nmodifiers | Number of Modifiers | Specifies the number of modifiers | Number | |
mo__modifiers | Modifiers | Add new modifier | Structure | |
mo__modifiers/varname | Variable name | Cell of strings | 'volumeFlowA' | |
mo__modifiers/attribute | Attribute | Cell of strings | 'start' | |
mo__modifiers/value | Value |
Ports
| Name | Type | Description | IO Type | Number |
|---|---|---|---|---|
fluidPortA | implicit | Hydraulic port A | input | 1 |
fluidPortB | implicit | Hydraulic port B | input | 2 |
fluidPortPilot | implicit | Hydraulic port pilot | input | 3 |
Port 4 | implicit | Spool stroke | output | mo_enableStrokeOutput |