MATERIALS HANDLING
Secondary belt cleaner location geometry
Operators should mount some secondary cleaners at least 50mm from the point the belt leaves the head pulley. In addition, they should check the X dimension with the idler dimensions for adequate installation space. [Fig. 3] A similar analysis of the location of a Martin Precleaner shows that with a 1,200mm diameter head pulley, users can install two primary cleaners and a secondary cleaner. Extra tertiary cleaners would be possible but may not be necessary if operators mount two precleaners and a secondary on the head pulley.
Assumption: Top and bottom runs of the conveyor belt (X) are parallel entering head pulley and leaving snub pulley [Fig. 2]
Variables: ϴ = Wrap angle of belt around head pulley
ω = Wrap Angle, ϴ, - 180 degrees
H = The height of the opening for the Secondary belt cleaner blades and frame installation
= Radius of Head pulley plus lagging, plus belt thickness
Rh Rs
= Radius of Snub pulley plus lagging, plus belt thickness. (Snub Pulley Diameter default value: 0.64 × head pulley diameter per DIN 22101)
T = The width off the opening for the Secondary belt cleaner blades and frame installation
W = Length of belt segment tangent to both the Head and Snub pulleys
Secondary mounting space example [Fig. 3]
X = Distance between top and bottom runs of the conveyor belt
Y = The vertical distance between the top run of the conveyor belt on the Head pulley and the tangent point where the belt leaves the Head pulley and starts the return run
Secondary mounting location basic layout [Fig. 2]
costs. Consider structure and work platforms that allow belt cleaner inspection and maintenance. There’s also the option of motorised
pulleys that off er energy advantages and weight saving. This also opens up space for belt cleaner installation and maintenance. Since all rotating components (including the main bearings) are located inside the pulley, the external stub shafts need minimal space to be mounted to the structure. Finally, mounting belt cleaners
properly that are accurate to within a few millimeters will help them perform optimally and limit the possibility of belt damage during cleaning or repair. Contracting with the belt cleaner
supplier ensures proper installation with minimal change and the new chute is well maintained.
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CONCLUSION To gain the direct and indirect long- term cost benefi ts of reduced fugitive material, operators should properly specify, design, and install a belt cleaner system. However, compliance is also an issue. OSHA, 1926.1412(d) and MSHA 75.362 states: “A competent person must begin a visual inspection prior to each shift the equipment will be used, which must be completed before or during that shift.” Safe access with adequate space for installation, maintenance and inspection is critical to supporting longer system life and a lower cost of operation.
Todd Swinderman is CEO Emeritus at Martin Engineering.
www.martin-eng.com
Primary, secondary and tertiary cleaners are all specially engineered for purpose and placement
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