Valve 1 in Dynamic Transfer Pull Mode

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Navigation: Main Page -> Models -> Pressure Changing Models

Related Links: Setting up Transfer Pull Network, Dynamic Transfer Simulation Mode, Valve 1 in Steady State and Dynamic Transfer Push 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.

The Dynamic Transfer Pull mode is only available in SysCAD 9.2 Build 135 or later.

For Dynamic Transfer Push mode, please refer to Valve1.


Diagram

Valve image001.gif

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

  1. 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.
  2. 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.
  3. The valve maybe turned on/off using the WithControls option, found on the Parms Tab.
  4. 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.
  5. 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.
  6. 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

  1. Valve-1 tab - Contains general information relating to the unit.
  2. VLE - Optional tab, only visible if the VLEquilibrium is enabled in the Evaluation Block.
  3. Parms - Allows user to define capacity and operation mode for the valve.
  4. Info tab - Contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
  5. Links tab, contains a summary table for all the input and output streams.
  6. 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.

Symbol / Tag Input / Calc Description/Calculated Variables
Common Data on First Tab Page
Requirements
Method None No pressure drop
Drop Fixed Pressure Drop
Fixed Fixed Pressure
Atmos Atmospheric Pressure.
VLEquilibrium List box Vapour Liquid Equilibrium (VLE) is enabled here. If this is 'On' then the associated page, VLE becomes visible and may be configured. Note: This option may automatically adjust the species make-up.
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.
PressIn / Pi Calc The actual pressure at the inlet of the valve.
Press_Change / dP Calc The pressure change in the valve.
PressOut / 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 ???
PowerSupply...
Source List Box The power supply can be specified via Menu Command View - Power Supplies, depending on the option selected on the Power Supply page, the power can be on/off. This can be used to trip valves if required.
Available Default Returns the status of the power supply.
Load...
PowerFactor Input The power factor used to estimate the shaft power.
ShaftPower Input Estimates the ShaftPower based on the Power Factor and flow through the valve.

Adding this Model to a Project

Insert into 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 Project Configuration for more information on adding models to the configuration file.


Insert into Project

 

Insert Unit

Piping

Valve(1)

See Insert Unit for general information on inserting units.