Premier Foods switches to infra-red on sauce production line
8 Nov 2011
Bury St Edmunds, UK – Premier Foods has reported efficiency gains of more than 10% following the installation of a custom-designed, carbon infra-red oven on a cooking sauce production line at its Bury St Edmunds plant.
The Bury St Edmunds site produces sweet pickles & relishes; a wide range of table sauces, branded & own label; and in particular, the range of Loyd Grossman sauces.
The Heraeus Noblelight oven, which replaced a hot-rinse system, has also improved the working environment around the production line as well as delivering energy savings compared with the steam-fed, hot jar rinsing unit.
After cooking, the cooking sauce is pasteurised in-line and delivered to the jar filler at a temperature of +94ºC. The new set up saves space and time by eliminating the need for a flat bed pasteuriser post bottling.
There is always a danger of thermal shock, cracking or breakage of the jars, when filling glass containers, which is caused when the temperature difference between fluid and glass is too great.
Previously, the cooking sauce jars were pre-heated in a rotary hot water rinse system. Here the gripped jars were injected with very hot rinse water, emptied and then fed to the filler machine. However, dwell times varied, with the result that the glass jars sometimes did not reach the temperature required to avoid thermal shock and breakages occurred. This meant that the line had repeated stoppages and delays.
To address this problem, Premier Foods approached conveyor system manufacturer SFT-UK, which recommended that a Heraeus infra-red oven should be considered for the glass jar heating. A124kW infra-red oven was, subsequently, installed on the production line.
SFT-UK modified the existing line by removing the hot water jar rinser and installing a new Paxona SFT sidegrip Jar inverter/filtered air cleaner. The infra red oven was installed immediately after the air cleaner. This stainless steel oven is in two sections, one with four 24kW zones and one with two 13.8kW zones.
An optical pyrometer measures the temperature of the jars as they leave the oven and this temperature is displayed on the front control panel. Manual or automatic control can be selected. In manual control, the operator can manually adjust the system’s power by means of a potentiometer to achieve the required temperature.
In automatic control, the power is automatically regulated to maintain a pre-set jar exit temperature. All the infra-red emitters are fitted with failure detection so that the line is shut down in the unlikely event of emitter failure. If the line needs to be stopped for any reason, the carbon emitters switch off virtually instantaneously to prevent overheating of any jars in the oven.
Since installation, Premier Foods has noted less downtime, improved reliability and the 10% increase in line speed, as well as positive feed back from the workforce.
“We have a notice board on the production line and the operators use this to highlight all their comments, both negative and positive. We were having a lot of negative comments about the old rinser,” explains Stephen Ward, project manager at Premier Foods.
“With the new infra-red oven, all the old complaints have been resolved and the workforce are now happy that, with the drastically reduced downtime, they can now consistently meet production targets, in a more comfortable environment,” he added.
