Air today, not gone tomorrow
15 Jan 2000
Around a tenth of all the electrical power consumed nationwide is attributable to the production of compressed air. It is vital, therefore, that plant operators obtain the maximum efficiency possible from their compressor equipment. Rental contracts, such as Atlas Copco’s Contract Air scheme, offer industry the opportunity to purchase just the process air that is needed. Moreover, it guarantees the price for compressed air, over whatever period best suits the customer.
If all this sounds too good to be true, it may pay plant managers to follow the example of Lawson Mardon, one of Europe’s largest food industry flexible packaging producers, who, when the time came to replace compressor plant, took advantage of the scheme.
The scheme made sound practical and economic sense to Conrad Hill, Lawson Mardon’s engineering manager at the A L Group member’s Workington plant on the Cumbrian coast. This is where packaging film is extruded, blown and printed for leading food and confectionery brands. It is also a site where considerable investments have been made in new printing presses, packaging film production equipment and solvent disposal processes.
`Quality air is critical to our plant operation with printing equipment running continuously six days a week and other operational plant producing right around the clock, seven days a week, all through the year,’ explains Hill. `Our dependence on compressor plant output has meant that overhaul periods have had to be extended in the past. As a result, we found ourselves faced with the choice between a considerably expensive overhaul programme for the complete system - which included existing water-cooled, oil-free compressors - or capital investment in equipment replacement, which would be phased over three years. Plus, of course, there were servicing costs. At the same time, we also had to recognise a company commitment to energy-saving.’
Atlas Copco provided all the answers for Lawson Mardon, replacing a system of ageing 132kW compressors and associated dryers with a complete package comprising energy-efficient air-cooled oil-free ZT160 compressors, MD 400 dryers, GP filters, plus an electronic control system, air receiver and all associated pipework.
The savings were immediate. Whereas the original compressors were run in unison, the replacements are operated on a controlled cycle with one machine always on standby. This saves around 7OkW per hour. The new compressors eliminated the need for a water-cooling tower and water treatment, which according to Hill has been calculated to save up to £25,000 per annum.
The Contract Air installation was completed by Atlas Copco in two weeks, with hired standby compressor units taking over to maintain essential continuity of the plant’s air supply. This was particularly important for equipment that is processing film webs, reeling off at the rate of 400 metres per minute.
`It was a seamless operation,’ says Hill. `There was no equipment downtime involved and the air supply changeover wasn’t evident to machine operatives. What’s more, the Contract Air agreement meant that the company, and myself in particular, didn’t have to worry about the project. Every detail was taken care of for us.’
