Most positive discharge bucket elevators available in the marketplace today are driven by metal chains. In these elevators, a series of overlapping buckets are attached at intervals to a pair of metal chains. While metal chain designs vary from manufacturer, many designs incorporate sprockets with a solid bearing pin and rollers for guiding and gearing purposes.
While metal chains are generally quite strong and can be effective for driving a positive discharge bucket elevator, they are not without some disadvantages. These include the following:
- Metal chains must be regularly maintained. Regular maintenance by the end-user is one of the most important factors governing the life of a metal chain. Maintenance activities that need to be carried out regularly on metal chains include, cleaning, lubrication, and adjustment and tensioning.
- Metal chains can corrode and degrade. Some materials are aggressive to normal steels and will attack the integrity of a metal chain. Corrosive materials can cause pitting of metal surfaces, increasing the bearing pressure and wear rate. Materials such as nitrates will cause failure of stressed chain components due to nitrate stress cracking.
- Metal chains can be abraded. Some materials are extremely abrasive and if these materials come into contact with a metal chain, accelerated rates of wear can result. While it is possible to improve the abrasion resistance of metal chain components, this generally entails higher cost.
- Difficult to clean. The components of a metal chain represent numerous entrapment points where material can accumulate and degrade.
- Metal chains can be noisy. In operation, high noise levels can arise from metal-on-metal contact between metal chain components and other constituents of the elevator drive assembly.
In contrast to metal drive chains, TipTrak™ positive discharge bucket elevators from UniTrak employ a pair of rubber beltchains. TipTrak™ rubber beltchains are constructed from a specially formulated elastomer molded around a core of pre-stretched stainless steel aircraft cables. This unique construction results in a high-strength drive chain that has the following advantages:
- Zero maintenance. Compared to metal chains, TipTrak™ rubber beltchains run slack and do not need to be tensioned, regulated or lubricated. The pre-stretched aircraft cables that make up the TipTrak™ beltchain core mean that the beltchain will never stretch, loosen or require adjustment.
- High resistance to corrosion and wear. For applications involving aggressive, corrosive or abrasive materials, TipTrak™ rubber beltchains can be manufactured using elastomers that are highly resistant to chemical or abrasive attack.
- Easily cleaned. Unlike metal chains, TipTrak™ rubber beltchains have fewer entrapment points in which material can accumulate and degrade. The TipTrak™ rubber beltchain can also be washed while still mounted in the elevator frame, using a factory-installed Clean-In-Place (CIP) system or high-pressure water hose. Beltchains made from FDA-approved materials are available for food-grade applications.
- Quiet operation. TipTrak™ rubber beltchains run in a positive drive system that ensures quiet operation. No noisy metal-on-metal contact!
TipTrak™ positive discharge bucket elevators service the following applications:
- High-care conveying. Applications involving the transfer of materials where gentle handling is essential to prevent material degradation and breakage.
- Severe service conveying. Applications involving the movement of corrosive, abrasive or aggressive materials.
- Critical service conveying. Applications involving the movement of toxic, hazardous, or explosive materials.
- Cleanable service conveying. Applications where sanitary performance and the prevention of product contamination is essential.
TipTrak™ elevators are available in three construction styles: Open Tube, PEC (fully enclosed), and Monocoque (fully sealed). A variety of configurations are available to service almost any application. For more information on TipTrak™ positive discharge bucket elevators and the advantages of the TipTrak™ rubber beltchain, please contact our sales department directly.