Page 365 - ExtendSim User Guide
P. 365

Tutorial for Discrete Rate Systems 339
A basic discrete rate model
When you run the model with animation on, notice that the Valve is partially shut down for maintenance a random amount of time and that its maximum rate is reduced to 2 gallons/min- ute during maintenance. Also notice that fewer gallons of yogurt are produced during the pro- cess than before the Shutdown block was added.
Change the flow unit to containers for the filling process
It would be difficult to ship the processed yogurt without putting it into containers. The model assumptions state that the yogurt mix is packaged into containers at a ratio of 12 containers per gallon of liquid. To represent this:
Delete the connection between the Merge block and the Yogurt tank.
Add a Change Units block to the model and connect it between the Merge and the Yogurt tank. Label the block Change Unit 1.
The model should now look like the screenshot to the right.
In the dialog of the Change Units block:
Do not change the first setting (Change units from: gallons)
Changing the flow unit
In the popup for the second unit setting (to: gallons), select New Unit and name the new flow unit containers.
So that each gallon will result in 12 containers, enter Conversion factor: 12 containers/ gallons. (Be sure to select containers/gallons from the popup menu.)
If you check the box for Show unit change on icon in the Change Units dialog, the area above the icon will display the text gallons=>containers.
After the settings have been entered, the dialog of the Change Units block should look like the following:
Dialog of Change Units block with user entries
When the model is run, the number of yogurt containers produced each minute, and thus the total number of containers processed, will vary depending on the Valve’s maximum rate and the flow restrictions caused when there is not enough fruit for the mix. Although it may vary from the example model, the plotter should indicate that approximately 370,000 containers of
Discrete Rate

   363   364   365   366   367