Improving filling efficiency for road and railway wagons
Solids handling equipment specialist Ajax Equipment has supplied the test rig, including static screw vertical elevator, for an ambitious project being undertaken by the Wolfson Centre for Bulk Solids Handling Technology at the University of Greenwich to improve the filling efficiency of road and railway tankers.
As powders flow from a storage hopper into a tanker they can become aerated making them more free-flowing and 'bulking out' the materials. In consequence the tanker can often appear full (by volume) when in fact it is under filled (by weight). To get around the problem, transport companies will either pressurise the tank or drive the vehicle around the site to settle the contents before resuming filling operations. This is both time-consuming and expensive. The Wolfson project is designed to research into developing a technique to make the discharge of materials into the tanker more predictable and in so doing improve the condition of the materials after filling.
“Tankers and big bags are particularly prone to the problem of aerated materials distorting their filling efficiency. In one case a big bag filling machine rated for 5 tonnes per hour was actually running at 2 tonnes per hour due to aeration. Our project is about modifying the bulk materials flow behaviour so that aeration is significantly reduced,” commented Richard Farnish, consulting engineer, The Wolfson Centre.
The test rig comprises two 1m3 capacity hoppers, screw feeder, pipework and vertical elevator. It will be used to store and recirculate a range of materials such as fly ash, cement, flour and sugar, for example. “We asked Ajax Equipment to provide the test rig because of their technical and manufacturing skills and capability. The Ajax static screw vertical elevator is ideal for this application where we are faced with tight space constraints for the test rig,” said Richard Farnish.
Lyn Bates, managing director, Ajax Equipment will have a wider technical support role in the project. “We are delighted to be involved in this project. Aeration is an all too common problem that also affects storage hoppers, IBC's and many other packing and filling operations. A key feature of the installation is that, apart from various other benefits, the new Olds Screw Elevator will transfer material is a more densified and settled condition than a conventional screw elevator” he said.
The Wolfson Centre for Bulk Solids Handling Technology is a department within the Medway School of Engineering at The University of Greenwich, Medway, Kent and has specialised in solving materials handling problems since 1973. The Centre began its existence researching problems associated with pneumatic conveying of powders and granular solid material in pipelines and has since expanded its areas of interest to include hopper & silo design, and instrumentation & control of bulk solids handling systems. Its extensive test facilities are housed in over 1,000 m2 of floor space. These facilities are continuously being updated to meet research and test requirements of industrial clients.