The general objectives of the project are the development of sensors, which can detect deposits on internal surfaces of processing equipment, primarily tubes and plate heat exchangers, in processing plants, and the development of an ultrasonic cleaning device for a tube heat exchanger.
Sensors are being developed, which can detect deposits on internal surfaces of processing equipment, primarily tubes and plate heat exchangers, in processing plants. An ultrasonic cleaning device is also being developed for a tube heat exchanger. The sensors and cleaning device can be connected to a personal computer (PC) based process control system.
Concerning ultrasonic sensors, investigations on how the detection measurement is to be performed with respect to transducer configuration, wave type and frequency, have been carried out and with existing transducers it has been possible to measure simulated fouling films form 0.5 to 6.0 mm thickness.
With respect to ultrasonic cleaning, a modified bioluminescence technique for detecting very thin fouling deposits, including types which do not contain viable cells, has been developed.
The single element sandwich transducer has shown very limited cleaning effect for ultrasonic cavitation cleaning. A horn transducer with amplified vibration amplitude has also been developed, which can be mounted on the outer wall of the component to be cleaned and an experimental cleaning set up, based on excitation of 1 foot steel pipes with the horn transducer, has been built.
Trials have shown that the optical sensor reading was dependent on the process conditions. Therefore a reference sensor able to compensate for optical changes in the milk is under construction.
The vibration sensor, made as an integral part of a plate heat exchanger element was constructed as a prototype. The sensor was able to detect fouling layers to a layer thickness of 0.1 mm and possibly lower.
Finally, a process control system has been constructed for a pilot plant consisting of a plate heat exchanger heated by water under pressure and a feed pump.
The sensors and cleaning device will be connected to a PC-based process control system.
The aim is to create possibilities of better hygienic status, thereby ensuring the shelf-life and quality of products from food processing plants.
Methods investigated have been:
1. Ultrasonics (both for sensor application and cleaning); ..SP 0 2. Optical analysis;
3. Vibration analysis.
Funding SchemeCSC - Cost-sharing contracts