Big weighbridge order from Anglian Water

Weightron Bilanciai have been chosen to supply all the weighbridges, groundwork, control points and ancillary equipment for 18 major treatment works in the Anglian Water region

With increasing environmental legislation and greater costs for the treatment and disposal of sewage, Anglian Water is investing nearly £1.5 million in order to dramatically improve the way it monitors the amount of sewage, sludge and treated sludge that moves in and out of its major treatment works.

Anglian Water has over 1000 sewage treatment works spread around its operating region.

Sludge from these plants is treated at its major treatment works and this involves considerable intersite movement of untreated sludge together with the export of treated sludge, primarily for use in agriculture.

In addition to this, these works also handle significant amounts of sewage from rural communities brought in by independent contractors.

Traditionally there has been only limited control on incoming sludge and not only has this resulted in lack of the required audit information but also in loss of potential revenue.

A measure of the magnitude of this is given by the fact that Anglian Water has estimated that the payback time for this project will be within five years.

This new project involves the installation of weighbridges and control points at 18 major treatment works in the Anglian Water region.

Each 18 metre, 50 tonne weighbridge is fully automatic and detailed information identifying vehicles and weights of sewage deposited is dialled out on an hourly basis to Anglian Water's offices in Cambridge.

A comprehensive system of barriers controls the vehicles entering and leaving the unmanned weighbridges and vehicles are identified via a smart card system on entry.

They are then either weighed both in and out of the site or weighed in only, with the stored tare information in the card used to determine the net weight of sludge deposited.

This information is used to provide accurate details of the amounts of sludge transported in and out of the treatment works.

In addition it is also used to generate invoices for contractors who can be refused entry to the sites if they have not paid their bills.

In practice there are advantages for the contractors who are now only charged for the actual amounts of product they bring, rather than being automatically charged for full loads.

Chesterfield based weighing specialists, Weightron Bilanciai have been chosen to supply all the weighbridges, groundwork, control points and ancillary equipment for this important project The contract was won against stiff European competition and although cost was a vital factor in the decision process, the technical design of Weightron's weighbridges, combined with their expertise, flexibility and attention to detail, has played an important part.

Weightron has worked closely with Anglian Water throughout, providing practical advice which included suggestions on the optimum location for the weighbridges.

The original specification given by Anglian called for 12 surface bridges and 6 pit mounted units.

However, as the project has progressed, local requirements have resulted in this changing to 15 surface and 3 pit mounted units.

Another important factor taken into account by Anglian Water is that the design of the Weightron weighbridges is such that they can be moved if the layout of any of the treatment works changes in the future.

Weightron's ability to offer competitive pricing comes not from cost cutting, moreover from comprehensive cost management which takes into account both the cost of the weighbridge itself and the installation, ground works and commissioning together with their ability to carry out self verification in line with weights and measures requirements.

Weightron are part of the internationally renowned Bilanciai Group head -quartered near Modena in Italy.

Bilanciai are the largest weighbridge manufacturer in Europe and they design and manufacture all the critical components for their equipment, including the load cells and instrumentation.

This means that Weightron can take advantage of large volume production.

One of the problems facing manufacturers is predicting weighbridge sales in any given period and a number of suppliers use outside fabrication contractors thus transferring some of the onus of unpredictability externally.

However, this ultimately carries cost penalties.

As Nick Catt, Weightron's technical director, explains: "We have refined our designs and manufacturing procedures to a level which gives us optimum flexibility to meet changing customers needs and demands.

All designs are fully produced on CAD systems and we have forged strong working partnerships with our steel suppliers who can adapt to changing requirements.

All the steel components for the different styles of weighbridges, from the large rolled sections forming the backbone to the small gusset plates, arrive at our works ready cut, drilled and shot blasted.

This means there is no unnecessary cutting and no wastage".

The key to Weightron's success can be attributed not only to the design and build efficiency of their weighbridges, but also to the installation and commissioning requirements, both of which have been streamlined based on many years of hard-won experience.

The weighbridge decks are fully fabricated and tested in-house.

An important feature of the Weightron weighbridge is the innovative yet simple restraint system.

When vehicles drive onto a weighbridge considerable end to end forces can be generated.

The restraint system limits both front to back and side to side movement without affecting performance.

The restraint system is set up prior to shipment and because it is located on the outside of the deck, minor on-site adjustments can be carried out very quickly and easily.

Weighbridges are tested in the factory with live load cells and then fitted with dummy load units which exactly replicate the live units.

The main cabling out to the junction box is also laid in prior to shipment.

Weightron's weighbridges are extremely robust, yet light weight, especially compared with competitive concrete weighbridges.

This reduces transportation costs and means that foundations can be less substantial (and hence lower cost) without any detrimental effect on reliability and performance.

On arrival on site, the weighbridge can be lowered onto the foundations with the dummy load cells in place.

The locator plates and restraint system can then be secured to the foundations.

Like the restraints system, the load cells are mounted on the outside of the bridge, maintaining a low profile and allowing simple access during commissioning and maintenance.

The weighbridges use fully weld sealed stainless steel rocker pin load cells which produce excellent performance and reliability.

The base plate has an insulating disc which provides electrical isolation to minimise the effects of lightning strikes.

A sealing ring prevents any debris entering the base and the single column of the load cell is specially designed to compensate for the normal non-linearity associated with column load cells.

The full glass to metal cable entry seal and stainless bellows ensure full sealing to IP68 and the units can withstand extended periods underwater, an important factor, given the climate conditions of late! The rocker pin concept provides an effective energy restoring system which ensures the weighbridge deck returns quickly to equilibrium after the vehicle has driven onto the weighbridge.

All the weighbridges supplied to Anglian Water are required to meet weights and measures requirements and therefore must be calibrated and stamped accordingly.

Weightron are certified for self verification which means that they can carry out the complete calibration procedure without using external approval authorities.

This not only reduces costs, but also means that calibration can be carried out precisely when required avoiding unnecessary delays.

Anglian Water is pleased with the overall professionalism portrayed by Weightron and admit that it has changed its requirements several times throughout the project, often at short notice.

However, Weightron have met these challenges with continued enthusiasm and dedication, ensuring that their client has a system which they are satisfied with.

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