T-ring microwave drying apparatus

Claim 2

Microwave drying apparatus for moisture-laden dielectric materials, comprising a waveguide system in the form of two waveguides arranged in a closed ring, and a tubular leg communicating with and extending away from the ring, said leg being adapted to be connected to a microwave generator, and a slot in the ring through which material to be dried can be moved with the longitudinal center line of said material on an electromagnetic center line of the waveguides, said electromagnetic center line being a location in the waveguide slot for which the length of one of said waveguides equaling a, and the length of the other of said waveguides equaling b, where a and b are measured from the tubular leg through the respective waveguides to said location, the relationship of a and b to each other being b a + (2m + 1) ( lambda /4) where lambda is the wavelength of the microwaves in the waveguide and m an integer.

Claim 3

Microwave drying apparatus as claimed in claim 1 wherein said waveguide is in the form of a substantially rectangular ring having a first pair of opposite sides interconnected with a second pair of opposite sides, said tubular leg being connected to one of said sides and forming with the latter side a T-junction.

Claim 4

Microwave drying apparatus as claimed in claim 2 in which said slot is in one of the sides of said second pair.

Claim 5

Microwave drying apparatus as claimed in claim 1 including a meter in said tubular leg for microwave energy transmitted through the material.

Claim 6

Microwave drying apparatus as claimed in claim 1 including a microwave generator coupled to the tubular leg, a meter in said tubular leg for microwave energy transmitted through said material, and a controller for the generator and operated by said meter to increase and decrease the microwave energy directed to the material inversely relative to the transmitted microwave energy.

Claim 7

Microwave drying apparatus as claimed in claim 1 in which said waveguide system is in the form of an elongated casing having a central wall extending longitudinally thereof and terminating short of opposite ends of the casing, said wall forming said two waveguides on opposite sides of the wall, and said tubular leg being connected to one of said ends of the casing and having a longitudinal center line aligned with the central wall.

Claim 8

Microwave drying apparatus as claimed in claim 6 in which said slot is formed in the casing through one of said waveguides on one side of the central wall.

Claim 9

Microwave drying apparatus as claimed in claim 6 including a meter in said tubular leg for microwave energy transmitted through said material.

Claim 10

Microwave drying apparatus as claimed in claim 6 including a microwave generator coupled to the tubular leg, a meter in said tubular leg for microwave energy transmitted through said material, and a controller for the generator and operated by said meter to increase and decrease the microwave energy directed to the material inversely relative to the transmitted microwave energy.

Claim 11

Microwave drying apparatus comprising a plurality of spaced-apart and aligned waveguide systems; each waveguide system comprising two waveguides arranged in a closed ring, and a tubular leg communicating with and extending away from the ring, a slot in the ring through which material to be dried can be moved with the longitudinal center line of said material on an electromagnetic center line of the waveguides, said electromagnetic center line being a location in the waveguide slot for which the length of one of said waveguides equaling a and the length of the other of said waveguides equaling b, where a and b are measured from the tubular leg through the respective waveguides to said location, the relationship of a and b to each other being b a + (2 m + 1) ( lambda /4) where lambda is the wavelength of the microwaves in the waveguides and m an integer; said slots of said waveguide rings being aligned and having a common electromagnetic center line, and a common microwave generating means connected to each of the tubular legs of said waveguide rings.

Claim 12

Microwave drying apparatus comprising a plurality of spaced-apart and aligned waveguide systems; each waveguide system comprising two waveguides arranged in a closed ring, and a tubular leg communicating with and extending away from the ring, a slot in the ring through which material to be dried can be moved with the longitudinal center line of said material on an electromagnetic center line of the waveguides, said electromagnetic center line being a location in the waveguide slot for which the length of one of said waveguides equaling a and the length of the other of said waveguides equaling b, where a and b are measured from the tubular leg through the respective waveguides to said location, the relationship of a and b to each other being b a + (2 m + 1) ( lambda /4) where lambda is the wavelength of the microwaves in the waveguides and m an integer; said slots of said waveguide rings being aligned and having a common electromagnetic center line, and a common microwave generating means connected to each of the tubular legs of said waveguide rings.

Claim 13

Microwave drying apparatus as claimed in claim 10 including a meter in each tubular leg for microwave energy trAnsmitted through said material at the waveguide of said each leg.

Claim 14

Microwave drying apparatus as claimed in claim 10 including a meter in each tubular leg for microwave energy transmitted through said material at the waveguide of said each leg, and controller means operated by said meter for the flow of microwave energy from said generator means to said material to increase and decrease the microwave energy directed to the material inversely relative to the transmitted microwave energy in each tubular leg.

Claim 15

Microwave drying apparatus as claimed in claim 12 including a terminal power meter for measuring and a terminal absorption means for absorbing that portion of the microwaves generated by said generating means that is unable to enter any of said tubular legs.

Claim 16

Microwave drying apparatus as claimed in claim 13 including a controller means for said generator means and operated by said terminal power meter to increase and decrease the microwave energy relative to the energy reaching the terminal absorption means.

Claim 17

Microwave drying apparatus as claimed in claim 12 including a directional power meter located between the said generating means and all of said waveguide systems, said directional power meter measuring the total power transmitted through said material in said waveguide systems, said transmitted power flowing back to said generating means and that portion of the generated microwaves which is excluded from entering any of said tubular legs also flowing back to the generating means.

Claim 18

Microwave drying apparatus as claimed in claim 15 including a controller means for said generator means and operated by said directional power meter to increase and decrease the microwave energy generated by said generating means inversely relative to the energy flowing back to said generating means, as measured by said directional power meter.