Dear Mike

We may be able help you with this application. Please give me the lift height, working time over which you want to achieve 500 t per day, and average density of material to be elevated.

Thanks ■

Rexnord is perhaps the largest bucket elevator manufacturer in the world. We have supplied over 4,000 bucket elevators to over 60 countries worldwide. We are the only manufacturer of bucket elevators that manufacturers all it's own key components such as chains, gearboxes, bearings, couplings,etc. Therefore, we take full responsibility for all aspects of the equipment and can offer you after-the-sale service on the entire piece of equipment throughout it's life cycle which can be 30-40 years or more. We have supplied chain elevators with lifts in excess of 70 meters and belt elevators with lifts in excess of 100 meters. Capacities over 1,000 metric tons per hour are possible with Rex Bucket Elevators. Your application is one we would typically handle with a chain type bucket elevator. Our chains are designed to offer a predictable and measureable wear life for ease in maintenance planning.

If you can provide us with the following, we would be in a position to make a recommendation for the proper elevator to handle this application.

1.lift required? -

2.Density of material as it would be handled in elevator? -

3.What percentage of material lump size is over 50mm?-

4.How many hours per day will elevator be operated to reach the 500 tons per day capacity required? -

5.How will elevator be fed? -

6.Is elevator to be installed outdoors or inside a building? If outside, access to the elevator head section may require a service platform to be supplied with ladder access. We can supply of you may wish to design and supply to conform to your own building structure. Let us know your preference.

7. When is delivery required?

8. Where will elevator be installed?

Regards,

Richard A. Skroski

Rexnord Corporation

Conveying Equipment Division

Director - Marketing and Training ■

It is not a good idea to elevate 40 mm to 80 mm limestone with a bucket

elevator. It is impossible to feed all the limestone into to buckets on the

90 degree incline. Therefore, a percentage of the limestone will end up in

the boot. Everytime a bucket hits a limestone rock in the boot, a shockload

occurs. Since it is impossible to calculate the tension produced by a

shockload, the result will be bucket damage plus either buckets pulling off

a belt or chain stretch. In addition, extra wasted horsepower is necessary

to pull the buckets through the static conveyed material in the boot and

extra wasted horsepower is necessary to extend the material above the

enclosed structure the bucket elevator is feeding in order to utilize it's

capacity.

You will be far better off using a corrugated sidewall belt for this

application. Assuming it is properly designed, it will operate with

relatively trouble free service.

David Dicke

Product Manager

Beltwall Division of Beltservice Corporation

USA

ddicke@beltservice.com ■

I do not agree with the previous responder that a bucket elevator should not be used in this application. We have many bucket elevators operating successfully handling limestone and other materials greater than 50 mm in size.

I agree with the previous writer that you need to keep large lump material out of the elevator boot to prevent digging. Some manufacturers design their elevators as digging type elevators and perhaps the experience of the previous writer is with these type designs. That is not the way to properly handle this material. The key is properly feeding and controlling the material as it is fed to the elevator buckets. Our Hi-Load or Continuous discharge type bucket elevators are slower speed, gravity discharge type elevators, typically used where large lump material in excess of 50mm in size is to be elevated. In these designs, we use a properly designed inlet opening and loading leg or chute if you will, inside the elevator, to confine and guide the material into the buckets instead of into the boot. The key is to keep material out of the boot through proper inlet positioning, design and proper bucket selection. If this is done in the elevator design, there is no reason why a chain bucket elevator will not work properly in this application.

Once again, a chain elevator of our design offers a very predictable and measureable chain wear life. The user can periodically measure chain elongation once or twice a year and chart it's wear from year to year. By comparing this to published data in our service manual. Limestone is not a particularly abrasive material to handle. Therefore, many years of chain and other component wear life is possible when properly handling this material.

Regards,

Richard A. Skroski

Rexnord Coprporation

Conveying Equipment Division

Milwaukee, Wisconsin - USA ■