Wear parts and bushing manufacturer Vesconite Bearings is seeing a considerable uptake in sales of its hanger bearings into the US beet and cane sugar industry, as well as to palm oil processing plants in Africa.

“We have supplied hanger bearings to these markets for years, as well as for fertilisers, minerals and powders. The more demanding a screw conveyor, the more that application requires an advanced bearing material, making Vesconite the ideal candidate,” says development engineer and consultant Juan van Wyk.

He explains that Vesconite has been specially developed for hanger bearings for screw conveyors, a critical consumable wear part, making it an ideal fit.

One of the main conveyed mediums is palm fruit fibres after the liquid content has been removed. The conveyors are highly loaded, and the rotational speeds of the screws becomes important when specifying a bearing material.

“Certain screws will have a higher PV value than others and this directly determines the suggested polymer grade,” notes van Wyk.

"The PV value refers to the load (P) carried by the bushing, and the surface velocity (V), which in this case is the rotating speed,” he explains.

If the PV value is too high, the bearing might melt owing to the heat that is generated by friction. Certain conveyed mediums are also highly abrasive, providing opportunities for increasingly advanced bearing materials such as Vesconite’s HiTemp 150 food-grade bearings.

Other mediums conveyed by screws in the palm oil industry include steriliser fruitlets, filter cake, whole and cracked nuts, kernels and shells, with some of these being oily in nature.

Van Wyk points out that some of the main benefits of using Vesconite as hanger bearings in screw conveyors is the product’s wear-resistant properties, which improve the service life and reduce costly maintenance and downtime.

“The self-lubricating properties also reduce and, in some cases, completely eliminate the need for greasing,” he enthuses.

Other advantages include the immediate availability of stock bearing sizes based on industry standards, bearing materials being food-grade specified, and a high level of manufacturing adaptability owing to Vesconite’s wide range of machining capabilities. “Vesconite can supply any custom bearing sizes for unique or custom screws,” he says.

When comparing Vesconite with traditional materials in these applications, Van Wyk explains that Vesconite has a lower coefficient of friction when used without lubrication than bronze bearings have with grease.

Vesconite is designed to suit applications where standard bearing materials are not adequate considering the operating parameters. “Greasing intervals can be eliminated or reduced. This makes the product exceptional. The low-friction properties limit damage to the mating parts, which is even more beneficial,” he notes.

The material also machines very easily, which means customers can use standard metalworking equipment to machine their hanger bearings in house if needed. Further, standard stock is readily available in a wide range of shapes and sizes, which is extremely beneficial for urgent jobs, such as breakdowns.