It’s Not Hard with Hardy

Glendinning is the largest independent supplier of quarry and concrete products both to the trade and direct to the end user in Devon and Cornwall. The company was established in 1958 by two brothers Ernest and Jack Glendinning, and today is owned by the founders’ families and is still very much a family business.

One of the most important factors in this business is being able to successfully move the products on the trucks from one place to another, carrying the right amount of product. However, this was an issue Glendinning faced.

Each of Glendinning’s trucks are supposed to carry 25 tons of product and the trucks are

measured on a weigh scale before leaving the quarry. It was found that they were not always carrying the prescribed amount of product, varying between extremes of 22 to 36 tons.

As it takes additional time to load and unload the product and travel around the site, the company saw an increase in time, running costs, fuel consumption and more.

There were also unseen costs of increased health and safety risks. Even though tipping product from a truck is not an exact science, there could sometimes be occasions which involve several ‘tuning trips’. Furthermore there is an axel loading limit on the trucks that should not be exceeded.

The weight readings being misread may have been due to the resonant vibration from the sorting screens, which runs through the steel work and affects traditional load cell readings. Ambient temperature variations change the properties of the belt which can further affect the weight readings.

Glendinning had previously attempted to resolve the issue. Initially the conveyor was fitted with a Ramsey International Belt Weigher. This had unreliable Modbus communications so the instrument was replaced by an Applied Weighing load cell amplifier. This only provided a 4-20mA output and required lots of PLC programming to give weight readings. It proved to be effective for static loads only, not offering enough updates/second to be used dynamically.

On hearing of the weight fluctuations, well-meaning operators attempted to ‘trim’ the dispensed amount. Unfortunately due to the random nature of the error this could sometimes exacerbate the problem.

Glendinning then got in touch with Routeco to help. Routeco proposed a Hardy Process

Solutions HI4050 instrument to be used with the same load cells and mechanics in place. The Hardy unit offers many advanced features including the ‘WaverSaver’ algorithm which is designed to mitigate the effects of vibration.

The instrument was installed with the ‘WaverSaver’ on its weakest of 5 settings 0.25Hz. The conveyor system dispensed mixtures of 9 different products, and in the 6 months that the Hardy instrument has been in use, the dispensed amount has shown only 1% variation for all weathers and products.

“It’s a pretty good set up, Auto Zero is set to ignore weights below 4kg as being belt variations.” said Carlos Moya – Hardy International Sales Coordinator.

The Hardy range is both easy to use and powerful, the WaverSaver feature has made a real difference here and Ian was able to set it up from scratch with no training.

There are other features that could be useful here too, with the load cells being high up and inaccessible maintenance and fault finding could be difficult. The Hardy Integrated Technician Summing Box provides remote switching of individual load cells making it easy to spot any faulty cells without having to leave the office.

Hardy’s C2 Calibration feature also allows for weightless calibration when used with C2 Load Cells. This is very useful when calibration is difficult or requires heavy weights.

To purchase the Hardy Process Solutions HI4050 click here. 

For more information email info@routeco.com or call 0370 607 1000.

Robert Stebbings - Automation & Software Product Sales Specialist