Valve 1 in Dynamic Transfer Pull Mode
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Navigation: Models ➔ Pressure Changing Models ➔ Valve 1 ➔ Dynamic Transfer Pull Mode
| Valve 1 in Steady State and Dynamic Transfer Push Mode | Valve 1 in Dynamic Transfer Pull Mode |
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Related Links: Setting up Transfer Pull Network, Dynamic Transfer Simulation Mode
General Description
This page is for project running under
Network solution - Dynamic and Flow Calculation - Transfer Pull mode.
The valve model will deliver flow based on the user specified capacity and opening position, upstream flow availability and downstream flow limitations.
For Dynamic Transfer Push mode, please refer to Valve1.
Diagram
The diagram shows the default drawing of the Valve, with the required connecting streams. The unit will not operate unless all of the above streams are connected.
The physical location of the connections is not important; the user may connect the streams to any position on the drawing.
Inputs and Outputs
| Label | Required Optional |
Input Output |
Number of Connections | Description | |
| Min | Max | ||||
| Input | Required | In | 1 | 1 | Input stream to valve. |
| Output | Required | Out | 1 | 1 | Output stream from valve. |
Model Theory
- User may set unlimited flow for the valve by setting the CapacityControl option to Off. However, this option is only recommended if there is another piece of equipment in the flow network that contains capacity limitation. For example, if the valve is connected a pump, then the valve flow capacity may be set to Off.
- User may specify the flow capacity, this capacity represents the maximum flow through the valve at maximum opening position. This value is not dependent on pressure.
- The valve maybe turned on/off using the WithControls option, found on the Parms Tab.
- The valve opening maybe adjusted using the WithControls option, found on the Parms Tab. NOTE: this is only valid if a capacity value has been specified.
- The actual flowrate through the valve will be determined by the amount of flow available, the valve opening position (if used) and downstream flow limitation.
- User may set a pressure drop method, and this will be used to calculate the pressure leaving the valve. This is for display purposes ONLY.
Data Sections
Summary of Data Sections
- Valve-1 tab - Contains general information relating to the unit.
- VLE - Optional tab, only visible if the VLEquilibrium is enabled in the Evaluation Block.
- Parms - Allows user to define capacity and operation mode for the valve.
- Info tab - Contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
- Links tab, contains a summary table for all the input and output streams.
- Audit tab - Contains summary information required for Mass and Energy balance. See Model Examples for enthalpy calculation Examples.
Dynamic Valve1 Page
Unit Type:Valve-1 - The first tab page in the access window will have this name.
| Tag (Long/Short) | Input / Calc | Description/Calculated Variables / Options |
| Tag | Display | This name tag may be modified with the change tag option. |
| Condition | Display | OK if no errors/warnings, otherwise lists errors/warnings. |
| ConditionCount | Display | The current number of errors/warnings. If condition is OK, returns 0. |
| GeneralDescription / GenDesc | Display | This is an automatically generated description for the unit. If the user has entered text in the 'EqpDesc' field on the Info tab (see below), this will be displayed here. If this field is blank, then SysCAD will display the UnitType or SubClass. |
| Requirements | ||
| Method | None | No pressure drop |
| Drop | Fixed Pressure Drop | |
| Fixed | Fixed Pressure | |
| Atmos | Atmospheric Pressure. | |
| PressDropReqd / PDropReqd | Input | The required pressure drop. Visible if the Drop method is selected. |
| PressureReqd / P_Reqd | Input | The required outlet pressure. Visible if the Fixed method is selected. |
| VLEquilibrium | Off | Vapour Liquid Equilibrium is off. |
| On | Vapour Liquid Equilibrium (VLE) is enabled. The associated section, VLE becomes visible and may be configured. Note: This option may automatically adjust the species make-up in Qo. | |
| Results | ||
| MassFlow / Qm | Calc | The total mass of material flowing through the valve. |
| TemperatureIn / Ti | Calc | The temperature of material at the inlet of the valve. |
| TemperatureOut / To | Calc | The temperature of material at the outlet of the valve. |
| PressureIn / Pi | Calc | The actual pressure at the inlet of the valve. |
| PressChange / dP | Calc | The pressure change in the valve. |
| PressureOut / Po | Calc | The actual pressure at the outlet of the valve. |
| DensityIn / Rhoi | Calc | The density of material at the inlet of the valve. |
| DensityOut / Rhoo | Calc | The density of material at the outlet of the valve. |
| VapourFracIn / Vfi | Calc | Vapour Mass Fraction at the inlet of the valve. |
| VapourFracOut / Vfo | Calc | Vapour Mass Fraction at the outlet of the valve. |
| Transfer Pull Mode | ||
| TN... - This section lists information about the Transfer Pull local Network | ||
| SourceCount | Calc | The number of possible sources where material is available. |
| QmAvail | Calc | The total amount of material available from all sources |
| QmAvailNR | Calc | The total amount of material available (not restricted) from all sources |
| AvailRho | Calc | The density of material available, used to calculate the volumetric flowrate |
| FreeCount | Calc | |
| QmDemand | Calc | The total demanded mass flow from downstream process |
| LinkPull | Calc | |
Parms Tab
| Tag / Symbol | Input / Calc | Description/Calculated Variables | |
| FC(FlowCapacity)... | |||
| CapacityControl | Off | The maximum mass flow through the pump will be set to unlimited amount (uncontrolled) | |
| ByMassFlow | The maximum mass flow through the pump | ||
| ByVolumeFlow | The maximum volumetric flow through the pump | ||
| Qm.Capacity | Input | Visible when ByMassFlow option is selected. The required pump Capacity in mass flow if the pump is operating at 100% speed. | |
| Qv.Capacity | Input | Visible when ByVolueFlow option is selected. The required pump Capacity in volumetric flow if the pump is operating at 100% speed. | |
| MeasRho | Calc | The density of material entering the pump | |
| WithControls | TickBox | Enables / Disables the Posn... Section. If enabled, allows the control of valve opening using some simple linear relationship. The Capacity flow specified under FC section is the maximum flow through the valve at 100% opening. | |
| Posn... - This section is only visible if the WithControls tickbox is selected. | |||
| Type | Position | Allows the control of the valve on/off and % opened. | |
| Pos & Stroke | Allows valve to ramp up to its opening position in the specified valve opening time | ||
| Stroke Opn/Cls | Allows the valve to ramp up/down on opening position during open and close, instead of reaching its full opening in one single iteration. | ||
| Mode | Active | Displays minimum fields for normal operation of the valve | |
| Command(Latch) | Displays additional fields for control of the valve, usually used when connecting to PLC or operating Systems | ||
| Command(State) | Displays additional fields for control of the valve, usually used when connecting to PLC or operating Systems | ||
| Postion, the following field is visible with this mode. | |||
| State / On | Tickbox | Toggles the valve on/off | |
| N/C | Tickbox | No backward flow allowed | |
| Actual | Calc | The actual valve % opened. | |
| Required / Reqd | Input | The required valve % opened. | |
| OpenCmd | Tickbox | Signals the valve to open, usually used when connecting to PLC or operating Systems | |
| CloseCmd | Tickbox | Signals the valve to close, usually used when connecting to PLC or operating Systems | |
| LatchCmds | Tickbox | Latch command, usually used when connecting to PLC or operating Systems | |
| LatchState | Input | Latch state, usually used when connecting to PLC or operating Systems | |
| Open | Feedback | confirms the valve is opened, usually used when connecting to PLC or operating Systems | |
| Closed | Feedback | confirms the valve is closed, usually used when connecting to PLC or operating Systems | |
| Manual | Input | Used to override the valve opening, used mainly in control logic / PLC testing. | |
| MinOpening | Input | Sets the valve Min % opened limit. | |
| MaxOpening | Input | Sets the valve Max % opened limit. | |
| LeakOpening | Input | Sets the valve Leak % opened limit. | |
| Physical | Feedback | The actual valve opening | |
| ReverseAction | Tickbox | ?? | |
| Stroke Opn/Cls - Command(Latch) or Command(State), the following extra fields are visible with this mode. Usually used when connecting to PLC or operating Systems | |||
| Permissive | Tickbox | Toggles the valve on/off | |
| OpenCmd | Tickbox | Sends the valve open signal | |
| CloseCmd | Tickbox | Sends the valve close signal | |
| OpenInvert | Tickbox | Sends the valve open invert signal ?? | |
| CloseInvert | Tickbox | Sends the valve close invert signal ?? | |
| Pos & Stroke, the following extra fields are visible with this mode. | |||
| StrkTime | Tickbox | The time it will take for the valve to get to its required % opening | |
| Stroke Opn/Cls, the following extra fields are visible with this mode. | |||
| CloseTime | Input | The time it will take for the valve to close. | |
| LoOpen | Feedback | Signals the valve is at low opening position if it is less or equal to the LoOpenLimit | |
| HiOpen | Feedback | Signals the valve is at high opening position if it is greater or equal to the HiOpenLimit | |
| LoOpenLimit | Input | Sets the valve's low open position limit | |
| HiOpenLimit | Input | Sets the valve's high open position limit | |
| ActMemory | Tickbox | ??? | |
Adding this Model to a Project
Add to Configuration File
Sort either by DLL or Group:
| DLL: | Piping1.dll |
→ | Units/Links | → | Piping: Valve(1) | |
| or | Group: | Mass Transfer |
→ | Units/Links | → | Piping: Valve(1) |
See Model Selection for more information on adding models to the configuration file.
Insert into Project Flowsheet
| Insert Unit | → | Piping | → | Valve(1) |
See Insert Unit for general information on inserting units.