Belt UP!

'If we're talking about belt weighers integrated with process control systems then the continuous weighing market in the UK is a growth market,' says Mike Badham, group export manager at Defiant Weighing, of Sevenoaks, Kent.

The company was acquired 18 months ago by Norwegian weighing systems company Procon Engineering AS, part of the Prosafe group. Procon's systems manufacturing is in the process of moving to the UK because the parent group sees potential in the UK's onshore and particularly offshore markets.

However, Defiant's belt weigher, with its characteristic side fitting load cell, is not the company's keystone; it's only a part of the range.

'We are not really chasing the belt weighing market per se. Excepting the process industries, it has been in decline in recent years [a view echoed by Rospen, below]. A typical Defiant job would be worth £25-30,000 but fitting out an aluminium plant could be worth in excess of £300,000. Recently, the group has supplied five of Russia's major aluminium (anode paste) plants.

Quite a number of belt weighing systems go into the domestic quarrying industries but Badham believes this to be just a replacement market. 'We wouldn't like to supply a £3000 belt weighing system just on its own,' he says. 'Nowadays it would just be part of a complete controlled delivery system with all the ancillaries.'

Defiant is interested in the international market as well as some of the niche markets in the UK. More recently, the company has been looking at the supply of total process control systems. It can supply all hardware, control systems and software a total package, including temperature and force measurement systems, process control technology including Scada and the necessary computing power.

Defiant designs special load cells that operate up to 5000t which it believes to be the largest in the world. Typical customers are in the metals and metal alloy processing industries. Parent Procon aims at the Scandinavian market and, prior to the takeover, its products were not readily available in the UK.

Competition in the UK market now comes from the likes of Honeywell, Phillips and Negretti Automation, all perhaps better known for delivering total process control systems.

Procon's systems can be fitted into any belt feeding system, Badham explains. 'On a conveyor system, we normally replace an idler (roller) set. The idlers are fully configurable to suit any application. The characteristic side acting load cell avoids problems caused by material falling from the belt that could clog up a horizontal system. In combination with our load cell there is a tacho to measure the speed of the belt and combining the data from cell and tacho gives the flow rate of the material.'

The 'new-look' Defiant has been tackling food producers, such as Nestle and Cadbury, pharmaceuticals manufacturers and the nuclear industries. Magnox reactors tend to use Defiant systems.

'For years we have supplied Nestle with its load cell indicators,' says Badham. 'Now we are able to tackle all of their process requirements and we are tendering for several more major clients including BNFL.'

Defiant is also one of the leading manufacturers of luggage handling systems in airports, having supplied many of the UK's and foreign airports.

The company's loadcells also suit a number of applications offshore, in drilling mud delivery systems (see, left) and in platform anchor cable monitoring and control systems. Procon is involved with the current Texaco Caplain and Britannia projects. Offshore it is important to consider the effect of the heave of the sea. Procon supplies systems to platforms which use compensation devices that measure the heave angle and counter the resultant forces.

THe screw tightens

Paradoxically, while Rospen Industries' managing director Kim David has seen an increase in weighing applications, there has been a noticeable decline in demand for pure belt weighers and weigh belt feeders particularly from sectors like coal and limestone.

David is confident that Rospen's alternative enclosed weigh screw feeders are performing well.

'The market has changed,' he says. 'Historically, a company may have chosen a weigh belt feeder, but now industry is more aware of how technology has advanced. Now, customers are going for loss-in-weight feeders which are more reliable in terms of mechanical integrity and the degree of control.'

Nevertheless there are still applications for Rospen Industries' belt weighers. Recent projects include cereals, food additives and agro-chemical applications. 'Continuous weighers present some benefits in project cost and planning in on certain applications.'

The food, pharmaceutical, plastics and chemical industries account for the bulk of Rospen's production activity.

David believes that for any continuous weighing applications the benefits of using weighed augers, which retain all the materials, are clear: they are robust, reliable, user-friendly and virtually maintenance-free.

These factors have prompted a swing towards the enclosed weigh screw feeder. Among the industries to realise these benefits is flour processing, with Rospen systems handling flour and milling additives at rates of between 50 and 45,000kg/h with weighed screw conveyors.

Containment qualities have also been important to the coffee sector with airborne moisture drastically affecting the quality of the product. In another application altogether, the explosives industry has been quick to recognise the merits of material containment during the production process and utilises this technology on several sites for their ingredients handling.