Polymer Vanes Last 3 Times As Long In Vacuum Rotary Pump

Vanes made of the bearing polymer Hitemp 150 have lasted three times as long as traditional vanes in servicing company Septic Tanks (Pty) Ltd’s vacuum rotary pump, a Broom B35.

The pump is used to create a pressure difference that sucks up the waste liquids from septic tanks. Pumps involved in such operations should not come into contact with sewage, ideally. However, where septic tank pumping is not monitored continuously, overflow from the transport truck can make its way to the pressure vessel and on to the vacuum rotary pump. The vanes in these pumps thus need to be cleaned. In addition, the vanes need to be able to operate at high temperatures, since the pumps can overheat due to operation for long periods.

Armed with information about vane operating requirements, when the original laminate vanes in Septic Tanks (Pty) Ltd’s Broom B35 pump needed replacing as frequently as every six months, the waste-sector servicing company turned to Vesconite Bearings, the maker of various polymers, for a solution to this unique operating environment.

Vesconite Bearings technical sales consultant Phillip de Villiers recommended Hitemp 150, an engineered polymer that is wear-resistant and can withstand temperatures of up to 150ºC. This material will not delaminate like the original equipment manufacturer-supplied material, a thermosetting phenol formaldehyde resin that impregnates layers of cotton to produce a hard synthetic plastic, he reasoned.

The trial result has been impressive: Hitemp 150 did not delaminate and was resistant to overheating. In addition, the new polymer vanes coped well with the frequent pump cleans that were required when waste material accidentally entered the pump.

Septic Tanks (Pty) Ltd owner Charl Neuhof is also pleased that the Hitemp 150 vanes continue to operate after a year and a half, while the phenolic alternative had to be replaced after six months. Moreover, he is enthusiastic about the reduced maintenance costs that are associated with the product, which can be cleaned in-situ — unlike the previous variety of vanes that had to be removed prior to cleaning because of their high levels of swelling when exposed to water.

Since testing of the B35 vacuum rotary pump vanes has gone well, Neuhoff plans to replace the vanes on its fleet of truck pumps as they fail. His four trucks are used in the Johannesburg North, Pretoria, Hartebeespoort, and Brits areas of South Africa, with three out on the road daily, each carrying six 6,000-liter loads of waste material a day. The five vanes that were employed in the B35 pump measured 35mm x 6mm x 330mm and had chamfered edges, but vanes for the other pump models that will be introducing the Hitemp 150 vanes will have different dimensions.