Dear Archons,

The same rules for pulley elevation apply at the at the discharge end applies as at the tail end. That is, it is preferable to have the surface of the pulley in-line with the surface of the center idler. By doing this, you will avoid placing undue stress on the idlers, pulley, and belt.

Regards, ■

Dear Mr. Archons

Usually to reduce the transition distance, we prefer the terminal pulley (tail/head) face is to be at one-half the depth of troughing.

In your case, the required transistion distance is about 750mm to 850mm depends on belt tension at that pulley when the pully face is at one-half the depth of troughing, otherwise it simply roughly doubles.

Hope, this may clear your doubt.

GSSV Suresh ■

Dear Mr. Archons,

If it is NN belt, you can simply take BELT WIDTH/18-20.For your case it is 30 to 35mm is comming. But it also depands on troughing angle,tension....

Regards.

A.Banerjee ■

Dear Mr. archonsengr,

You have 600mm wide belt and 20 degree trough rollers. The belt width being narrow and troughing angle being shallow, mostly, you may not need pulley elevation (rising) with reference to general belt line, unless you have acute difficulty in transition length at tail end or at head end. It also appears that you may be using textile fabric belt and not steel-cord belt. The transition length is less for textile fabric belt and more for steel cord belt.

Looking at all these inferences, you may check suitability of putting pulley periphery top point on general belt line (the line touching the top of middle rollers).

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

Non of the responses (nor do the standards) address the mechanics that influence a proper transition and therefore predict the consequences of your choice. A troughed belt has a neutral axis which is its CG (center of gravity). For a troughed belt on three-equal-rolls that axis is about 1/3 the trough depth above the top of center roll. When this axis lines up with the pulley surface there is neither up lift nor downward load caused by the transition. The transition that splits equally the trough depth results in belt uplift while the transition that lines up the top of the center roll with the top of pulley results in a downward load. These can be calculated easily from the geometry of the neutral axis belt line and the belt tension. In idustry it is very common to split equally the depth of trough and then have to shim the idlers up because they fail to contact the belt.

Joseph A. Dos Santos ■