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<< Click to Display Table of Contents >> Case Description |
  
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<< Click to Display Table of Contents >> Case Description |
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Case Manager is a tool that allows the user to create multiple operating cases for the same conveyor configuration and components. These cases allow the user to model different operating conditions so they can evaluated for the conveyor being evaluated.
For any conveyor, many variables go into estimating the drag, the total power required from the drives and the resulting belt tensions. Some forces such as lift force (simply defined by gravity) are dictated by the route and moving load and, subsequently, these forces are difficult to minimize without altering the conveyor route. Some resistances, such as rubber indentation and idler drag can be minimized by selecting the appropriate components. Others such as misalignment are affected by installation tolerances.
With any new design, many of these variables can only be estimated until components are bought, built, installed and running. To handle this uncertainty during the design phase, possible options can be considered and a range of resistances developed for design purposes.
The high side of the friction range represents the worst case high power possibility which might occur with component selection, the coldest days, unfavorable loading pattern and typical/poor installation tolerances. The low side of the friction range represents the worst case low power possibility which might occur with component selection, the warmest days, favorable loading pattern and good installation tolerances. In short, the highest values dictate some component sizes such as the motors and the lowest values dictate other properties like idler spacing. Some components, like take-ups and curve radii, need to be able to accommodate both extremes. By designing to a friction range, much of the design risk is mitigated.
When considering the probable range of friction the following design parameters are typically considered (in BA):
•Rubber Indentation
•Idler Resistance
•Idler Manufacturing Tolerance
•Installation Tolerance (Idler Alignment)
•Idler Tilt
•Temperature: Cold temperatures affect grease and rubber, resulting in changed (normally higher) frictional resistance.
•Regenerative Conditions
Another major design condition involves possible loading conditions. The loading patterns that are encountered in normal operations are a primary consideration. The following are often considered, at a range of drag values.
•Fully loaded at design capacity
•Empty
•The sequence of loading the conveyor going from empty to fully loaded
•The sequence of unloading the conveyor going from fully loaded to empty
Other loading patterns creating different running conditions are possible, although some of them are not probable and often they are very temporary.
•Inclines are all loaded, often the high power requirement
•Declines are loaded, often the low power requirement
•Loaded at greater than design capacity