Bucket Elevator

High-Capacity Belt and Chain Bucket Elevators

30.01.2008 | Author / Deskman: Beumer
Maschinenfabrik / Marcel Dröttboom

Continuous improvements and new developments have pushed bucket elevators to new heights. State-of-the art systems today offer elevating distances of more than 150 meter and capacities of 1800 m3/h, and more.

In many industrial sectors the use of vertical mechanical conveyors has become an indispensable link between different production processes. In comparison to pneumatic conveyor systems belt and chain bucket elevators have the advantage that they require much less energy and offer high reliability and long service life.

High-capacity chain bucket elevators as well as belt bucket elevators have proven their value in thousands of cases of permanent use under difficult and partly extreme conditions, and some manufactures offer made-to-measure bucket elevator solutions for even the most special application. The German company Beumer, for example, have pushed the development of such elevators to centre distances of more than 150 m and capacities of more than 1800 m³/h.

High-capacity Belt Bucket Elevators

Belt bucket elevators are mainly used for high-capacity vertical transport of powdery and small-grained products. Depending on the material granulation two variants of bucket connections are used. With a grain size of up to 25 mm segment mountings are used. For grains between 25 mm and 60 mm in size, rubber-batten mounting is more suitable.

Thanks to reinforcement of the belts with steel wires centre distances of more than 150 metres are possible. To achieve long service life, special connections between the bucket and the belt have been developed to prevent the buckets from tearing out and reduce wear on the belt to a minimum.

Central Chain Bucket Elevators

Lumpy, abrasive and hot materials such as clinker, clinker chip and limestone ballast are reliably conveyed by using high-capacity central chain bucket elevators. With up to 4 different chains to choose from, the best fitting one can be selected with regard to capacity and height, while established chain safety standards are complied with. By using a high-strength version of central chains, a safe conquest of even great conveying heights has been made possible. And chain bolts with a tough core and defined hardness depth increase service life considerably. This is because a massive bolt with high core strength and hardened surface offers permanently low-wear operation.

In development, Beumer, for example, has oriented itself towards specific market requirements for fine tensile strength gradations and created a central chain offering low-cost use. The secure and force-fit operation of the bucket elevator makes a three-point support possible. The latter is formed by the arched shape of the dust flap adjusted to the chain wheel with two chain bolts. Beyond that the external socket forms, with its profile fitted to the bolt, a labyrinth seal and grease chamber which makes lifetime lubrication of the bearing areas possible even with temperatures up to 150°C. Material flow rates of more than 1100 m³/h can be achieved with a closer bucket spacing and denser bucket sequences. For graduated adjustment to the conveying capacity needed, ranges of bucket width, e.g. 400mm to 2000mm, are available as single or double bucket elevators.

Example of Application

With production of 32 million tons of cement per year and a total market share of 22 percent, Grasim Cement is India’s largest producer of cement. In the course of the construction materials industry’s economic boom in this country, the company has been steadily growing. In 2004 Grasim took over the UltraTech Cement Works from Larsen and Toubro. In September 2006 the Beumer Group was given a major order to supply a package of 47 bucket elevators for their new cement plants (3 x 3.5 million tons per year).

The order for Grasim Cement Group includes high-capacity belt and central chain bucket elevators in various sizes and with varying capacities. Part of this order were six high-capacity belt bucket elevators which are, due to their centre distances of 145.65m, amongst the highest in the world. Each pair of these belt bucket elevators feeds one of the three high-capacity kilns with raw meal. With a bucket width of 1000 mm its conveying capacity comes to about 550 tons of raw meal per hour. The conveyor machinery is fitted out with high-strength Beumer steel wire belts with zones free of steel wiring.

New Elevating Record

In order to cope up with increased demand, Ambuja Cement, part of the Holcim Group, is setting up a large cement plant at Bhatapara, India, with a capacity of 8500 t/d for which Beumer has been awarded with the supply of a high-capacity belt bucket elevator of a class of its own.

According to the German manufacturer, this bucket elevator, with a centre to centre distance of 158 m and a capacity of 650 t/h, is so far the tallest in the world. The preheater will be fed with raw meal by the new belt bucket elevator. Besides its enormous height, the elevator is distinguished by having the remarkable width of 1250 mm. The new cement kiln line currently under implementation and delivery of the elevator is scheduled for early 2008.

Beumer Maschinenfabrik GmbH & Co. KG