Making Soup
9 Aug 2001
The New Covent Garden Soup Company started manufacturing soup in 1988. One of the first companies to produce high-quality fresh soups and sauces for sale in major supermarkets, it was a rapid success; it is now by far the largest producer, cornering 40 per cent of the market.
It's hardly surprising, then, that NCG's process engineers are looking for ways to make their plant more efficient and productive. A key part of this was reducing wastage to ensure that as much soup as possible is packaged for sale.
This has led to the company investigating new ways of dosing the soup into its distinctive cartons. NCG had used a rotary piston filling valve for this, but its large number of moving parts leads to wear in the piston, housing and seals. This, along with the design of the nozzle itself, can lead to variations in the amount of soup which actually reaches the package. The company decided to test a new filling method using a magnetic flowmeter and nozzle, and turned to the National Measurement Partnership to help confirm the accuracy and practicality of the method. NMP, an initiative coordinated by the Department of Trade and Industry and the National Physical Laboratory, aims to improve the understanding of the importance of accurate measurement in UK industry, using training, calibration laboratories and consultancy services for industry.
NCG turned to the magnetic flowmeter method because it promised to reduce the variation in filling volumes, by allowing control of the flow-rate of soup into the packages. It also has a more hygienic, lower-maintenance construction than the rotary piston valve, the company says.
NMP confirmed that the equipment would present real advantages to the company, but also pointed out additional requirements. To work properly, the device needs to operate under a constant head of pressure. NCG solved this by incorporating an extra pressure compensation loop into its operating system, controlled by the holding vessel's automation system.
Introducing the valve has made NCG a cleaner place. The minimum variation in fill volumes is now 5g per carton, compared with 15g for the rotary valve. Across a whole batch, according to the NMP, this represents a saving of 1200kg of soup. Cleaning times are also reduced. Even more marked is the drop in time needed for preventative maintanance from eight hours to just one.
But expansion isn't everything; in these energy-conscious times, keeping consumption to a minimum is also important. When NCG installed new compressor capacity, energy efficiency was at the forefront of the company's thoughts, and the concerns were passed on to compressor supplier Ecoair.
The Peterborough site was the first to receive its new compressor installation. This uses two rotary screw air compressors, connected to a sequence controller which matches the performance of the compressors to the plant's requirements. Rather than running the system on a pressure switch cascade, this runs the compressor in a 'pressure window' via a transducer, which allows small-scale process control applications to be run at very low cost. According to Ecoair, this can reduce the cost of running the lead compressor by as much as 20 per cent.
Air drawn into the plant first passes through two refrigerant air dryers which reduce the dewpoint of the air entering the plant to 3°C, and a set of air filters to remove coolant and water particles larger than 0.01micron. The compressed air is stored in a 1000litre vertical air receiver.
