Patent ID: 7470876

Claim:
A microwave heating device comprising: a waveguide extending in height from a top wall to a bottom wall and in width from a first side wall to a second side wall to define along a portion of its length an exposure chamber having a generally rectangular cross section; a microwave source supplying electromagnetic energy to the exposure chamber in the form of electromagnetic waves propagating along the length of the waveguide through the exposure chamber in a direction of wave propagation; wherein the exposure chamber extends in the direction of wave propagation from a first end to a second end and forms a first port through the waveguide at the first end into the exposure chamber and a second port through the waveguide at the second end into the exposure chamber; a conveyor extending in width from a first edge to a second edge and passing through the exposure chamber along a conveying path in the direction of wave propagation via the first and second ports and carrying material to be heated by electromagnetic energy in the exposure chamber; wherein the first side wall forms a first enclosed passageway extending from the first port to the second port between the top and bottom walls and wherein the second side wall forms a second enclosed passageway extending from the first port to the second port opposite the first passageway across the width of the exposure chamber to accommodate the first and second edges of the conveyor.