Are you referring to the impact idlers inside the tail pulley frame?

Impact idlers are a real necessity att transfer points. ■

Some designers increase the return belt clearance for better cleanup access in the loading station. Then the carry side leaving the tail pulley is positioned higher than desired when entering the load/skirt system. They then install a bend or snub pulley after the tail to bring the carry belt to the horizontal plane desired.

I would call this a snub after the tail pulley not before.

The name could be any of the nominations you desire: bend, snub or deflector although deflector is a stretch. ■

Dear Shri Ravi,

The earlier respondents have already given detailed information. I would like to state as below :

1) If the tail pulley diameter is not very large compared to the distance between carrying run and return run as decided by the stringer size and idlers arrangement, then there is no necessity for snub pulley or deflector pulley at tail end. This also depends upon the tension in the belt.

2) If the tail pulley diameter is sufficiently large than the distance between carrying run and return run, then one uses snub or deflector pulley at tail end. But this pulley level will be below the tail pulley.

3) One can use two tail pulleys (or two bend pulleys) placed one above the other, if more dimension is required between carrying run and return run in that zone.

4) I have not come across any pulley placed above the tail pulley and external to the belt loop. I do not see any necessity for such pulley.

Regards,

Ishwar G Mulani.

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

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

Bend Pulley is typically named as a non-driven pulley used to redirection the belt orientation.

Snub Pulley is typically named as a redirection of the belt after or before a drive to increase is wrap angle.

Deflector Pulley is typically named for pulleys that bend the belt off its horizontal plane to: a) apply/stabilize the belt for cleaning, b) cause the belt's resultant force to act on a load cell reading, c) enable a belt speed tachometer pickup with small wrap, ect. They could have other orientation. Their formalities are not well defined. Invent!

Let us know if we have cleared the mysteries or mysterious. ■