Stacker Conveyor Drive Unit
Mid drives are a common thing for a lot of conveyor belts as
they allow flexibility due to a possible lack of space for a head pulley drive system.
There are two drive pulleys pulling the bottom belt with a passive hydraulic take up pulley. As your head pulley is passive anyway they probably installed what they had in stock for the headpulley drum and shaft being a common inventory item for both types of installations.
lzaharis ■
Re: Stacker Conveyor Problem
The head pulley shaft with an intermediate drive is larger diameter because it sees a higher force on the shaft than a head drive pulley sees.
With a head drive pulley, the force is the sum of the top side tension T1, and the bottom side tension T2. T2 is typically .38 to .8 times T1 depending on lagging, belt wrap and takeup type.
With an intermediate drive on the return run, the head pulley force is 2 x T1 as the belt is under high tension on both sides of the pulley.
The same applies to tripper head and bend shafts.
Pulley shafts are designed based on deflection due to belt load, torsion seldom governs the selection, so the fact that a drive pulley is a smaller diameter is likely not a concern. Since the head pulley is installed in a discharge chute, the bearing centres are probably wider than the drive pulley shaft which again requires a larger shaft to limit deflection. ■
Re: Stacker Conveyor Problem
Dear Mr. Minemechaz,
You have mentioned that there is a stockyard conveyor operating in conjunction with the stacker. You have also mentioned that drive house is at the middle of the conveyor. The stacker cannot cross the drive house, so it will be operating either ahead of the drive house or in the zone behind the drive house. This looks to be a specific arrangement to suit the particular need or as per the thinking of its designer. It is not possible to comment why somebody did so and so.
As for the effect of drive location and consequent effect on belt tensions and pulleys size, one has to consider the drive unit at alternative locations, design the conveyor and see that which is economical location along with compatibility to application requirement. One cannot precisely judge in advance the outcome of design in all cases. Certain expected results are known for widely used arrangements.
The fundamental requirement is that the drive arrangement for the stockyard conveyor should be selected such that it results into minimum tension so that stacker or stacker-cum-reclaimer machine length become economical and belt does not lift up at concave radius in the tripper zone of the machine. Such lift-up will result into malfunctioning of the system. The stockyard machine and yard conveyor should be designed as a complementary to each other.
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.
Pune, India.
Tel.: 0091 (0)20 25871916 ■
Stacker Conveyor Problem
Good day, we have a 48" stacker conveyor that is pulled from a drivehouse located in the middle of the conveyor. Unlike most of the conveyors I've seen that are driven from the head pulley, this one is not.
When conveyors are driven from the head pulley, usually the shaft in this location is larger than the others, for example, 10" diameter on the head pulley and 8" diameter on the end pulley.
Well, in this case, shafts on the drivehouse (where the stacker is driven) are 8". And the head pulley has a 10". Why? I guess I'm dusty on dynamics and physics but I just can't figure this out. Thanks for your help. ■