AggFlow

Screens

"blurb here"

Installing Screens

Select a screen from the AggFlow DM database or select Generic, then choose the screen type and size.

New screen sizes can be added as needed.

  • Select Adjust Size as Needed from the model list and AggFlow DM will automatically select a screen size based on the calculated area requirements.
  • The default efficiency is 95%. The lowest screen efficiency that AggFlow DM allows in calculations is 70%. If the calculation cannot achieve 70% the machine “red flags.”
  • AggFlow DM provides several screen area calculation features:
    • Immediately see the effects of changing various screen parameters.
    • Perform various types of screen carry-over calculations.
    • Try different screen area calculation methods and compare the results.

To Install a Screen

  1. Select the Screen category.
  2. Select the type of Screen. Choose from 1-4 decks or custom screens and place it on the worksheet (it will turn blue).
  3. Right-click and choose Select Model from the short-cut menu r.
  4. Select the desired manufacturer, make and model or choose Generic, screen type and size. Then Install.

Adjusting Screens

Use the Screen Area Calculation window to define operating parameters and water features.

Screen Area Calculations

  1. Screen Type

    • MESH (default) sizes range from 1/32" to 4".
    • PLATE sizes range from 2”-to-10”
    • BAR sizes ranges from, 2”-to-10”
    • EMPTY (material falls through the deck)

  2. Cut Size

    Enter the desired Split Point. AggFlow can accept various forms of data entry such as 1 3/4, #4 or 4M. Decimals must be entered with three places such as 0.9. Screens perform depending on how they are operated and often the cut size will differ from the actual screen opening size.

  3. Screen Carry-Over Calculations:

    Select the screen carry-over that most accurately models the plant operation. “Carry-over” represents the material that should pass through the screen but does not due to screen inefficiencies.

    • Near-size (default) assumes the carry-over will have far greater amounts of near-size material, with the percent and amount dropping rapidly as particle size decreases.
    • Even assumes the carry-over material will have an even distribution among all sizes passing through the screen.
    • None assumes the screen operates perfectly and all material that should pass through he screen does. There is no carry-over material.

  4. Calculation Method

    AggFlow provides several different calculation methods. When a change is made to any value in the Screen Area Calculation window AggFlow automatically recalculates the required screen size.

    • VSMA method (default). VSMA is the industry standard method for screen calculations.
    • Cedarapids Method. Uses the calculation developed by screen manufacturer Cedarapids.
    • Deister method. Uses the calculation developed by screen manufacturer Deister.
    • Kleeman. Uses calculation developed by Kleeman
    • Jaques. Uses calculation developed by Jaques
    • High Frequency and other custom screens use calculations provided by the manufacturer. Custom rate of travel, open area, and custom factor will need to be reviewed for each deck depending on manufacturer recommendations.

  5. Operating Parameter Tabs

    Use the available tabs to set specific operating parameters for each deck and to track power and emission factors for the screen.

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Create a New Screen Size

New screen sizes can be created to allow for a screen that is not listed in the screen database. New screens can be created as a new generic screen, or they can be saved under a new manufacturer and model in the Screen Database.

  1. Install the screen type from the screen equipment selections, right click on the screen and click on Select Model.
  2. Select the Create New Screen Size button from the model browser window.
  3. Enter the effective size (width and length). AggFlow DM will use these values to calculate total available screen area.
  4. Use the Effective Size to make labels or enter a custom label. The label will be displayed when the new screen is in use.
  5. To save the screen in the Database under a new manufacturer name enter the name and model under Identify Machine.
  6. Select Save to add the new screen size.
  7. To determine where the new screen size will be available in worksheets and projects, select the Store Data tab and select the databases to store the screen in. The Default selection is Local Machine.
  8. To delete a screen from the Database, select No for all the databases and this will remove the screen. Screens cannot be removed from the AggFlow DM Database.
  9. Use the Adjust Setup window to set the screen calculation methods factors, efficiency and rate of travel for each deck.
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Effective Size represents the total size. The screen efficiency factors account for variations in the actual effective screen area in the calculations.

Screen Operating Parameters

After installing a screen on the worksheet and establishing the set-up. Use the water and deck tabs to set specific operating parameters. Note that screen setup will be in the units that have been selected in user preferences. Imperial is referred to here.

Water Settings

Spray Bars

Turns the spray bars on or off for each deck. AggflowDM only changes the wet screen factor for a screen deck if the spray bar is turned on.

Spray Rate

Specifies the water rate flowing through the spray bars for each deck. Adding water without the spray bars on will not set the screen area calculation factor for wet screening.

Water in Product

Defines how much water is included in the material as it is carried off each screen deck. All of these inputs are different representations of the same calculation; therefore changes to one will update the others.

  • (gpm)/(st/h): Represents the flow rate added to each ton of material.
  • Solid Weight %: Represents the weight % of solids in the material (slurry).
  • Solid Volume %: Represents the volume % of solids in the material (slurry).

Wetbox Rate

Add water to the material before it enters the screen. The water added here will be included in the mass water balance of the plant and the calculation for water included in the product will be performed for all decks even if spray bars are not turned on.

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All water not included in these parameters is assumed to fall through the screen and is included in the remaining material.

Deck Settings

For each deck there will be a deck settings tab. The tab is dependent on the type of media selected (Mesh, Plate, Bars, Empty)

Rate of Travel

Enter the rate of travel (initial setting based on user preferences).

Set Discharge Bed Depth Ratio (DBD)

Set the DBD for the deck (Initial setting based on User Preferences).

Turn Spray Bars on/off

Turns spray bars on or off on the deck. (This changes the wet screening factor)

Select Slot Type

Select between square, short, or long slot.

Enter Open Area

Determines or changes the Open Area factor for the screen.

Set Efficiency Alarm

The screen will “Red Flag” when the calculated efficiency is below the designated efficiency. 70% is the default.

Overrule Calculated Efficiency

AggFlow will calculate using the percentage (70-98% range) entered.

Enter Custom Factor

Enter and name a custom factor for the screen. AggFlow will calculate using the custom factor.

Calculated Required Area

Displays the screen area as calculated using method formulas.

Power and Emission tabs

Store detailed information about the machine.

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Custom Screens

To Install and Adjust a Custom Screen

  1. Select Custom Screens from the category list and install the icon on the worksheet.

  2. Right-click and choose Select Model to open the Custom Screen selections window. Custom screens include:

    • Banana Screens
    • Trommel Screens
    • Self-defined Screens

  3. Select the screen type that is needed.

    The generic Custom screen option can be used to model any screen not already included in AggFlow DM.

  4. Set up the screen using Adjust Setup.

Custom Multi-Screens

Custom Multi-Screens provide the ability to simulate multiple screen decks within the same machine.

To Install and Adjust a Custom Multi-Screen

  1. Select and place the Custom Multi-Screen icon onto the worksheet.
  2. Right-click and choose Select Model.
  3. Select the appropriate custom screen option (the worksheet icon will be updated to that machine drawing).
  4. To open the custom screen machine for adjustment either right click and select Adjust Components, or double-click on the item or select it and choose Adjust Setup. This will open the adjustment window.
  5. Adjust each screen item in the component machine to represent the multi-screen machine in the plant.
  6. Monitors can be show in the adjustment window for each screen item. These monitors will not be shown on the worksheet.

Custom screens do not perform calculations other than calculating the carryover based on the efficiency. Custom screens do not calculate the required area.

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