The product is refractory component parts of a lining for a kiln which may be used to melt metals.
These range in size from 200 by 200 by 200 mm up to something four times this size in each direction. The item shown in the first photograph is about 800 mm long. The mould and the piece weigh about 100 Kg.
The microwave ovens, were situated in line with the customers current conveyor system. The intention was to allow the piece to be removed from the mould in real time to prevent bunching in the production system.
The units shown would normally hold two or three moulds. Each would be fed in singly after they are filled and a period of heating of 20 minutes applied. Thus every 20 minutes one mould went in and one came out ready to be de-moulded.
Although tailor-made for the customer's requirement this oven represents a typical design supplied to this customer. Their remaining 13 ovens followed this pattern with minor adjustments for the particular purpose.
 

The unit was designed to process wheat product. If wheat is stored above 26 per cent moisture by weight it tends to rot. It is often difficult to dry wheat when there are conglomerates of grain which remain moist when the single grains have dried. This is especially true when accelerated drying by hot-air his attempted. The effect of microwave heating is to moisture level.

The two features which we have not come across before are :-

1) The use of a choke section, which allows free entry into the microwave cavity. However, at this frequency the height is limited to five centimetres. The width is comparatively unlimited.

2) Use of photo cells to detect the presence of a load and the use of moisture detectors.
 

This shows a rubber conveyor belt microwave pre-heater. As previously mentioned it is possible to make a choke section of considerable width. This unit is some 10.6 M long and 3.8 M wide. The belt is made up of 5 layers of rubber and canvas. The advantages of microwave pre-heating of the belt was to almost double the output of the flat bed press and it made sure the canvas was completely dry before pressing thus stopping steam bubbles that previously had to be manually removed.

Microwave assisting in the manufacture of leather, where it is often required to heat the leather a number of times to allow oil, etc to enter to improve flexibility.

These wooden railway line sleepers arrive from Australia with 100% moisture by weight. Before use they have to be seasoned to reduce their moisture to 26%. This takes a very long time. Using relatively low intensity microwaves the treatment can be done in 10 hours. The sleeper on the right shows the result of drying in 3 hours and although some shakes occur these are comparable with the one produced with normal seasoning.