Apparatus and method for processing dielectric materials with microwave energy

摘要

The microwave apparatus for processing dielectric materials includes a number of tunable cavity devices arranged vertically one above the other, each having a movable piston. Dielectric conduit means extend downwardly through all of the cavity devices, passing through the various movable pistons. Each tunable cavity device has a microwave generator associated therewith so as to supply controlled amounts of power at frequencies depending upon the type of material being processed. The processing is monitored by additional cavity devices, each having a movable piston. Whereas the pistons of the power cavity devices are positioned so as to cause the material being processed to absorb a maximum amount of microwave power, the pistons in the monitoring devices are positioned so that a detectable amount of power is reflected. The amount of reflected power is indicative of an electrical characteristic, such as moisture. A signal is derived from each of the monitoring devices for controlling the amount of power to the power cavity device with which it is associated. Graphs are employed so that the optimum position for a given plunger can be selected for the greatest amount of absorption (or the least amount of reflection) to be attained and in order to determine the amount of microwave power to be supplied to a particular power cavity device.