Save and prosper

Whether you want to save power, cut component wear or keep potatoes in prime condition, highly-advanced automation is available to help keep the costs down. Colin Carter reports.

As more and more manufacturers look to reducing costs and producing goods in the most efficient way possible, we are seeing an almost unprecedented rise in the levels of industrial automation.

And this movement of products and components by machinery rather than huge numbers of people means that it’s boom time for automation suppliers.

The machinery is usually a mix of highly-advanced control hardware such as PCs, Programmable Logic Controllers (PLCs) and drives, with more prosaic engineering components such as gearboxes, chains, rods and belts at the sharp end.

The energy used in large plant can be huge, and consequently the savings can be enormous, even when small efficiencies are made.

For example, Guy Simms, Corus Strip Products’ energy optimisation manager, estimates that as much as 30MW of power could be saved across the company’s Port Talbot plant in South Wales by installing variable speed drives (VSDs) in a number of application areas.

When pumps or fans are used only at the load they need to run, savings can be made. And something like a 20 per cent reduction in speed can save around 50 per cent of the energy costs.

For example, VSDs can be used rather than having motors running at maximum power, and flow rates can be controlled by energy-absorbing devices such as baffles or valves.

At Corus, savings were found in areas such as the four cooling pumps used to fill quench tanks and one circulating pump. These were installed some time ago and were considered to be so over-specified that it was worth replacing them with VSDs.

This is just one example in Corus’ current programme which features the installation of some 24 ABB industrial drives, ranging in power from 140-400 kW, used for pumps in the company’s hot strip mill, the cold mill and fans in the coke ovens.

The cost of the entire installation is in the order of £2.5m — but the annual projected savings are reckoned to be around £1m.

But it’s not just heavy industry that is dependent on efficiency for survival these days. All manner of goods are highly price-dependent.

Drives, believe it or not, are playing a part in making the humble potato less expensive on your supermarket shelf. Mitsubishi F740 VSDs are used to run fans that keep stored potatoes at optimal climatic conditions for suppliers Crop Systems so they can be delivered — all year round — in prime condition when required.

Large fixed speed fans running at full speed were once used, but VSDs running at powers matching the demands of the facility are claimed to have reduced costs considerably.

As well as being used to make cost savings, VSDs can also reduce wear on components. At British Sugar’s Cantley plant, sugar beet is cleaned using a high-pressure spray water pump in a large rotating drum. A newly-installed system has seen components such as the pumps and the drum itself powered by various Control Techniques Unidrive SP drives.

These are designed to provide a high start-up current, which produces high torques to start processes. This minimises motor wear as well as reducing maintenance costs.

At Kensey Foods’ highly-automated Launceston plant, in Cornwall, a system for moving chilled desserts through the refrigeration store system has benefited from greater automation through reduced system downtime and an improved user interface.

The system has been upgraded with Schneider Electric’s Altivar Flux Vector inverter drives controlled by PLCs, which move the conveyors containing the desserts by a system of chains.

Linear encoders at each end of the lift provide positional data used by the controlling PLC so that it can identify any potential chain wear before failure occurs — and it gives enough advance warning to enable downtime to be planned economically.

Another improvement is in the provision of adjustable torque control for the motors. Dynamic adjustment of the torque required can be adjusted depending on the number of trays being moved. In addition, sensors can tell if any product trays are protruding from the store — thus preventing lift collisions.

The ability to prevent costly production downtime through chain failure has also led to a change in practices at German Village Products’ noodle drying plant.

The US food manufacturer produces noodles for big-brand soups, but was having problems caused by heat from one of its dryers. This, along with a build-up of flour, was causing the chain fitted to the dryer to stretch prematurely.

Although a new chain was routinely fitted every six months or so, this incurred hefty costs in installation plus a loss of product through downtime.

Engineers recommended fitting a long-life Synergy chain from Renold, which they hoped would double the life. In practice, the long-life chain has proved to be exactly that, and after two years’ service it is still showing no signs of wearing out.

Renold launched Smartlink at the end of last year to allow engineers to find out details about the loads that are being experienced by chains in normal use. The device, which consists of strain gauges, electronics and a battery, is attached to plates on one side of the chain.

As it travels, data concerning the loads and shocks is collected and recorded by a microprocessor. It can warn if damage is about to occur — or if the chain is in danger of breaking.

The data showing strain can also be downloaded for analysis, allowing engineers to fine-tune equipment to optimise performance or isolate problems to prevent chain wear.

It’s not only products, but the packaging of these products that can benefit from upgraded control components.

Siemens Automation and Drives, for example, has recently provided a solution for Norfolk-based HayssenSandiacre, manufacturer of machines for the bagging of foodstuffs.

When the packaging company received an order for vertical bagging machines it took delivery of Siemens’ motion control technology. This comprises Siemens’ Simotion D machine controller, a Sinamics four-axis drive platform and 1Fk7 servomotors and planetary in-line gearboxes.

The system not only reduced the machine’s footprint, but also used much of HayssenSandiacre’s existing controls. This meant that customers were familiar with the operations, and the company did not need to re-write its product documentation.

The upgrade is currently being phased-in across all the company’s intermittent bagging machines with a view to rolling out the system across all its continuous motion bagging line next year.