Originally Posted by bhagwatshrikant

Hello,

Is it possible to use continuous discharge type with belt bucket elevator? The application is for handling quartz. What will be the possible problems in continuous belt bucket elevator? Is it difficult to track / control belt sway. The height c-c distance is maxi. 27 mtr. The conveying speed is limited to 0.7 mps and conveying capacity is 30 TPH.

Regards,

Shrikant Bhagwat

Namaskar,

The problem is the quartz is very very abrasive.

I would talk to the folks at Sukup Elevator Company

as they have offices worldwide. ■

Hello,

For continuous bucket elevator with belt, some information is as below:

1) Centrifugal bucket elevator with belt is quite common. However, continuous buckets on belt type elevator has certain discharge issue, as mentioned below, and its use appears to be subjective to the choice between buyer and seller. The discharge issue arises due to buckets being not continuous as is being written, but there is about 10 mm gap between consecutive buckets.

2) For continuous bucket elevator discharge at head end, the material being emptied from one bucket has to jump and land on the back of bucket ahead. The jumping ability of the material gradually increases after crossing app 90 deg travel on head pulley. The jumping ability of various particle in buckets varies with respect to radial location, etc. and it is not single entity at this stage.

As this ability increases gradually, it passes under transition stage wherein some material jumps (moves) but fails to reach destination and fall into gap between belt and bucket rear face (bolted to belt). These gaps arise when buckets are traveling on head pulley where buckets cannot bend to curvature of pulley. The gap tends to become zero next second (when buckets leave pulley zone), in the process it traps / squeezes some material (very small / minute percentage) between belt and bucket. The squeezing reaction tends to weaken bucket grip on belt and overstressing belt at bolt-head.

3) When buckets go round boot pulley, the gap opens and material will have scope to dislodge and fall down. It may dislodge 100% but will also fall down after sufficient build-up.

4) To minimise the above problem, continuous buckets fixing bolts are kept below mid-depth, which is inferior location to take bending moment arising due to material scraping (partial scooping) resistance in boot. As against this centrifugal discharge buckets fixing bolts are at bucket top, which is ideal to withstand scooping resistance.

As for the continuous buckets on chain, there is no such issue because chain does not block passage behind bucket. Also bucket is bolted to rigid attachment of chain.

5) Centrifugal discharge belt bucket elevators are quite common for foundry sand.

6) Long tome back Link-Belt USA literature did not mention continuous belt bucket elevator, but some other company mentioned it.

7) The designer can study issue and decide accordingly. I prefer not to opine as general statement.

8) The topic being of widespread concern, the reply is in detail.

Regards,

Ishwar G. Mulani

Author of Book : Engineering Science And Application Design For Belt Conveyors (new print November, 2012)

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

Email: conveyor.ishwar.mulani@gmail.com

Website: www.conveyor.ishwarmulani.com ■