PRO-BELT

Horzontal Curve Design

PRO-BELT Horizontal Curve Design in Overland Belt Conveyors

Design Curves in Overland Conveyors with Confidence

can be used to design horizontal curves in any troughing belt conveyor of any length and belt sizes in either English or Metric units. The troughing belt system and the return belt system are both included in the design. The troughing idlers must be the 3-roller design of equal troughing angle on each lateral roll. The lateral rolls can be longer than the middle roll to allow more drift, if desired. The idler troughing angle is generally between 30 and 45 degrees. The return idlers must be a 2-roller "V" design. Return idlers generally have a troughing angle between 10 and 30 degrees but more commonly in the 15 to 20 degree range. Flat idlers cannot be used in horizontal curve conveyors neither on the troughing belt nor on the return belt.

calculates the drift to the inner curve and drift to the outer curve under any belt tension or loading condition. Maximum drift to the inner curve occurs at maximum belt tension when the belt in the curve area is empty. The conveyor requires a load case analysis with the conveyor loaded to the curve but empty thereafter. The acceleration belt tensions should be used to check the curve design for maximum drift to the inner circle. Tail drive regenerative conveyors would normally have a maximum inner circle drift with the opposite conditions; i.e., stopping with the belt empty in the curve and full thereafter. This program will design the curve for both loaded and empty conditions on the same report. The return belt can also be checked for drift to the inner circle and the outer circle.

Maximum drift to the outer curve occurs at minimum belt tension when the belt in the curve area is loaded. The conveyor requires a load case analysis with the conveyor loaded in the curve or throughout. The stopping belt tensions should be used to check the curve design for maximum drift to the outer curve. Tail drive regenerative conveyors would normally have maximum outer curve drift with the opposite conditions; i.e., accelerating with the belt full throughout. Many other load case possibilities should be considered.

allows faultless belt tracking of the conveyor belt by setting idler banking, tilt, and tracking.

The IDLER BANKING ANGLE or super-elevation is the primary conveyor design parameter used to provide a faultless tracking of the conveyor belt. The idlers are raised on the inner side of the curve to provide a slope to the idler base. Banking angles of 8 degrees are common. A high banking angle will succeed in reducing the empty belt drift to the inner curve but will also cause an increase in drift of the full belt to the outer curve. Banking with an idler tilt up to 2 degrees has been a successful approach to curve design. Provisions in the design should allow an adjustment of the idler banking, tilt, and tracking in the field, if necessary.

The IDLER TILT ANGLE is the secondary conveyor design parameter used to provide a faultless tracking of the conveyor belt. The idlers are tilted forward at the top in the direction of belt travel to provide up to 3 degrees of tilt to the idler base. The belt tracking will probably not be as effective as indicated by the program when set above 3 degrees. A tilt angle of 2 degrees has been shown to be a successful approach to curve design.

The IDLER TRACKING ANGLE is a tertiary conveyor design parameter used to provide a faultless tracking of the conveyor belt. The idlers are moved forward in the direction of belt travel on the inner side of the curve to provide up to 2 degrees of tracking to the idler base. Tracking utilizes belt friction on the idlers to effect a movement in the belt and is not the most reliable method for belt guidance. However, tracking can be used in the field to make minor adjustments in the belt drift. A small tracking angle can make a large change in the drift. The sum of tracking plus tilt should not exceed 3 degrees.

The TROUGHABILITY LOAD FACTORS are used to analyzes the effect in belt drift as a result of belt troughability. A belt which is stiff transversely has a reduced troughability and applies a greater force on the lateral idler rolls and a lower force on the central idler roll. A belt with greater stiffness and lower troughability actually improves belt tracking.

The MATERIAL FOLLOW FACTORS represent the ability of the material to follow the drift of the belt without moving toward the lower edge. A value of 1.0 represents a material that has no movement when the belt drifts on the idlers. The value will be zero for very free flowing materials that flow like water.

The BELT FRICTION ADJUSTMENT uses a friction multiplier to adjust the friction between the belt and the idlers. This friction is very important in layouts which include tilt and/or tracking of the idlers. The belt will not track as intended when the actual friction is less that assumed. The friction multiplier can be changed to see the sensitivity of the final horizontal curve design to friction.

The ALLOWABLE BELT DRIFT is calculated based on the input parameters. The allowable belt drift is dependent on the unused space on the lateral idlers, belt edge distance with the given material loading and material follow factors. The belt is allowed to drift slightly beyond the edge of the lateral rollers by an amount of 1 inch or 25 mm. The actual drift results is compared to the allowable belt drift and an "OK" or "FAIL" indicator is given for each section point on the curve. These results are given for all three conditions: 1) troughing belt empty, 2) troughing belt loaded, and 3) return belt.

produces a five (5) page report printout showing all input data and drift results for both the troughing belt and the return belt. The input data can be easily changed and the results viewed to analyze and optimize the curve design.

View Five (5) Page Horizontal Curve Report

produces six (6) graphs of the belt tension and drift data. Three (3) graphs show the belt tension at given drift intervals for three different conditions: 1) troughing belt empty, 2) troughing belt loaded, and 3) return belt. The other three (3) graphs show the actual belt drift at the various section point numbers based on given belt tensions for the same three conditions: 1) troughing belt empty, 2) troughing belt loaded, and 3) return belt.

View Six (6) Graphs of Belt Tension and Drift

is available in either English or Metric units. Click the following link to see the Price Schedule & Upgrade Order Information.

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users technical support answers.

Running PRO-BELT on Computers with the Windows 7, Window Vista, 32-bit CPU, 64-bit, CPU, Macintosh, and Linux Operating Systems.

Setup Details for Running PRO-BELT on Windows 7, 64-bit CPU, and Other Operating Systems.

Printing  PRO-BELT Reports to an Adobe Acrobat PDF File.

Converting PRO-BELT Reports to a "Rich Text File" or Document.

Converting PRO-BELT Graphics Data Page to a Rich Text File or PDF.

Printing on a local printer attached to the computer!

Printing on Windows 2000 and XP to a USB or Wireless Printer!

Printing on WINDOWS NT, 2000 and XP Network Printers!

Printing on WINDOWS 95 and 98 Network Printers!

Printing PRO-BELT Graphs!

Shaft Mounted Reducer Torque Arm Reaction and Pulley Shaft Load.

Calculating Tangent Dimensions for Concave and Convex Vertical Curves.

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