Flowforce Technologies impact weighers

Impact weighers are a unique device for measuring the instantaneous mass flowrate of free-flowing dry powders and grains. Measurement of dry powder flowrate both in process and at despatch has always been an issue for mines and production facilities. 

Raw material usage and production accounting relied on the accuracy of silo level measurements, theoretical calculations, and weighbridge despatch, all of which provided working discrepancies.

In process measurement for feeding and dosing of solids relied on the accuracy of batch weighing, loss in weight measurement or displacement calculations that were supported by product quality outcomes.

The instantaneous mass flow measurement provided by the impact weigher can eliminate the complexity and inaccuracy of other methods of measurement. First introduced in the late 1980’s their recent development has made these devices very robust and reliable and also suitable for a wider range of products.

Flow Force Technologies (FFT) products are designed and built in Adelaide and routinely operational in eight other countries  The company was acquired by South Australian engineering consultancy GJC Engineers in 2013 and immediately began researching new ways to improve the performance of its impact weighers and in particular: 

• Improving the measurement accuracy,
• Reliability of the measurement components,
• Dealing with high temperature powders,
• Dealing with powders high in dust,
• Coping with magnetic materials,
• Ability to easily wash and clean the units,
• Ruggedness and maintainability.

Glenn Jobling, Managing Director at FFT, says the company started development with the electronic components, looking to improve the accuracy of FFT’s impact weighers. Impact weighers measure the mass flowrates of free-flowing bulk materials by measuring the horizontal force produced by impact on a plate inserted in the product flow. Because only the horizontal force is measured, the accuracy of the measurement isn’t compromised by erosion or build-up of product on the plate. FFT partnered with electronics company Rinstrum to upgrade its software algorithms resulting in a new controller, based on FFT software, with higher accuracy and better reliability.

The improved controller was especially important for the transport industry where changes to legislation, specifically when it comes to overloading, meant that accurate load measurement had become a key for many customers.

A number of configurations were developed to attach the impact plate to the load cell with the most effective being the magnetic coupling arrangement that did result in considerable improvements in performance. However, a drawback to this system is that process minerals can’t be magnetic and it is also still unable to handle applications where the product temperatures is greater than 80°C.

By using a trapeze-mounted impact plate with an externally mounted load cell the units could deal with magnetic material and temperatures up to 120?C. It also meant that exposure to product dust was no longer an issue and the internals could be easily cleaned or washed out. An added benefit was that it could also then be used for explosive products.

Ruggedness and maintainability were two key qualities that FFT strived to include in its new impact weighers. Stainless steel is now used instead of painted steel to remove issues with corrosion and wear, and parts have been standardised, making units easier to repair. This can reduce customers’ spare part storage requirements and makes manufacturing easier, as components are now interchangeable across a number of sizes and designs.

These developments have made the FFT Impact Weigher the goto device for measurement of mass flow of free-flowing powders.

Impact weighers are used with great success within the cement industry allowing manufacturers to reduce waste and better control the quality of their product. Cement is made to quality specifications and manufacturers can measure the additive introduction in real time allowing them to keep the product as close to the specification as possible.

Processes in the rare earth mineral sector have also influenced FFT’s technology development. Rare earth mineral production involves producing different grades of product and samplers are used to collect samples for analysis.

As a consequence, FFT has developed an integral sampler for their impact weighers which allows for the collection of samples for laboratory testing to be done without interruption to the process.

For further information visit http://www.flowforce.com.au