Heko from Wickede (Ruhr) in Germany is a manufacturer of highly wear-resistant chains and components for conveyors and bucket elevators. In the almost 100 years of its company history, the company has gained experience internationally in a very wide range of industrial sectors, ranging from power stations and fertilisers to, in particular, its role as an OEM in the building material industry.
The conveying of bulk material in cement plants represents an environment in which only the toughest products can be used. Thanks to their decades of experience in this field, the Heko staff knows what to focus on in the production of chains. At the same time, in-house production has been tailored to the special needs of the construction materials industry: for example, one of the processes used by Heko for hardening its products is a special heat treatment method in vacuum furnaces with helium quenching. The capacity of the heat-treatment systems allows unit weights of up to 750 kg for the chain strands. This special heat treatment endows the products with particular properties, including a highly wear-resistant outer layer with a surface hardness of at least 800 HV and high fatigue strength, high breaking load thanks to the tough, fine-grain core, and extreme dimensional accuracy.
In addition to highly wear-resistant chains, Heko’s product portfolio also includes idler and tensioning units. Like chains, these products are extremely susceptible to wear as a result of soiling from dust and other deposits. This can lead to reduced lifetimes if, for example, bearings or seals fail. Heko idler and tensioning units therefore offer a particular benefit: the units are always fully integrated in the foot of the bucket elevator which thus prevents the egress of dust in the area of the bearing. At the same time, the tensioning units have been designed such that, if parts have to be replaced or maintenance is required, only a few short actions are needed to get them up and running again, which means that downtime can be minimized.
Another benefit, which comes particularly to the fore in the event of retrofitting, is that the Heko idler and tensioning units can be supplied pre-assembled in components. The delivery specification then includes the sprockets with replaceable raceway segments made of a special alloy steel and the shaft (made of normal steel, Cr-Mo steel or Cr-Ni-Mo steel, as required), bearing, chain guide rails and side walls with large openings for fitting.
In addition to the standard units for new bucket elevators, idler units can also be quoted for many other bucket elevators – with bucket widths ranging from 160 mm to 1600 mm. Just a few dimensions (width x depth x height) for the bucket elevator foot are required to permit the unit to be sized.
Another essential component for ensuring the smoothest possible operation of bucket elevators are high-quality bearings. In its LGH 18-4 and LGH 18-11 bearings, Heko offers products which achieve outstanding results especially with dry or highly abrasive goods. The bearing blocks can be mounted directly in the bucket elevator foot and bolted to the frame of the bucket elevator tensioning unit with just four bolts.
A highly wear-resistant bush is screwed to the ends of the return shaft with the maintenance-free bearings. This means that the return shaft itself is no longer subject to wear. The highly wear-resistant bush for its part runs in the bearing bracket, which is manufactured from a wear-resistant cast material. The bearing bracket has an opening at the bottom from which any product that has gained access can be ejected again. There is no longer any need for the plain bearings to have an additional dust seal or to be lubricated.
Since Heko is able to supply idler and tensioning units for fitting in new and existing bucket elevators and highly wear-resistant chains and bearings specially for cement plants, the company has a product portfolio which meets both the quality specifications and the cost requirements of its customers and is in conjunction with the know-how from almost 100 years of involvement in the cement industry.