Microwave drying apparatus and method

Claim 2

Microwave drying apparatus for moisture-laden dielectric material comprising a microwave generator, means for dividing microwave energy from the generator into two equal parts, and separate channels for directing said two energy parts to opposite sides of material to be dried, the length of one of said channels to the longitudinal center line of the material being equal to the length of the other of said channels plus a whole number of half wavelengths of the microwaves from said generator.

Claim 3

Microwave drying apparatus as claimed in claim 1 in which said channels are located to direct said two energy parts against directly opposite areas on said material.

Claim 4

Microwave drying apparatus as claimed in claim 1 including means for detecting the microwave energy that is transmitted through said material, and controlling means for reGulating the output of the microwave generator inversely relative to the level of the transmitted energy.

Claim 5

Microwave drying apparatus for moisture-laden dielectric material comprising a waveguide having two channels extending to outer ends on opposite sides of a path along which material to be dried travels, said path having an electromagnetic center line and said material being guided to travel with its center line on said electromagnetic center line and between said two channel ends, a microwave generator, a four-port hybrid coupling the waveguide channels to the generator, the length of one of said channels to the electromagnetic center line being equal to the length of the other of said channels plus a whole number of half wavelengths of the microwaves from said generator, said waveguide channels directing microwave energy from the generator to opposite sides of material moving along said path.

Claim 6

Microwave drying apparatus for moisture-laden dielectric material comprising a waveguide having two channels extending to outer ends on opposite sides of a path along which material to be dried travels, said path having an electromagnetic center line and said material being guided to travel with its center line on said electromagnetic center line and between said two channel ends, a microwave generator, a four-port hybrid coupling the waveguide channels to the generator, the length of one of said channels to the electromagnetic center line being equal to the length of the other of said channels plus a whole number of half wavelengths of the microwaves from said generator, said waveguide channels directing microwave energy from the generator to opposite sides of material moving along said path.

Claim 7

Microwave drying apparatus as claimed in claim 4 in which said two channel ends are located close to each other.

Claim 8

Microwave drying apparatus as claimed in claim 4 in which said channel ends are located directly opposite from each other.

Claim 9

Microwave drying apparatus as claimed in claim 4 including control means operated by microwave energy transmitted through said material to control the output of the microwave generator inversely relative to the level of the transmitted energy.

Claim 10

Microwave drying apparatus as claimed in claim 4 in which said channel ends are located directly opposite from each other whereby microwave energy transmitted through said material travels back through said channels, and control means operated by said transmitted energy to control the output of the microwave generator inversely relative to the level of the transmitted energy.

Claim 11

Microwave drying apparatus as claimed in claim 4 including microwave energy absorption means coupled to one of the ports of said hybrid.

Claim 12

Microwave drying apparatus for moisture-laden dielectric material comprising a hybrid having a common central section and a longitudinal center line, a first pair of arms projecting from one end of the central section on opposite sides of the center line, a second pair of arms projecting from an opposite end of the central section on opposite sides of the hybrid center line, a microwave generator coupled to one arm of said second pair of arms so that microwave energy therefrom is directed through both of the arms of the first pair, a waveguide having two channels, one connected to each arm of said first pair, said two channels extending to outer ends on opposite sides of a path along which said material travels, said path having an electromagnetic center line and said material being guided to travel with its center line on said electromagnetic center line and between said two channel ends, the length of one of said channels to the electromagnetic center line being equal to the length of the other of said channels plus a whole number of half wavelengths of the microwaves from said generator, said waveguide channels directing microwave energy from the generator to opposite sides of the material moving along said path.

Claim 13

Microwave drying apparatus for moisture-laden dielectric material comprising a hybrid having a common central section and a longitudinal center line, a first pair of arms projecting from one end of the central section on opposite sides of the center line, a second pair of arms projecting from an opposite end of the central section on opposite sides of the hybrid center line, a microwave generator coupled to one arm of said second pair of arms so that microwave energy therefrom is directed through both of the arms of the first pair, a waveguide having two channels, one connected to each arm of said first pair, said two channels extending to outer ends on opposite sides of a path along which said material travels, said path having an electromagnetic center line and said material being guided to travel with its center line on said electromagnetic center line and between said two channel ends, the length of one of said channels to the electromagnetic center line being equal to the length of the other of said channels plus a whole number of half wavelengths of the microwaves from said generator, said waveguide channels directing microwave energy from the generator to opposite sides of the material moving along said path.

Claim 14

Microwave drying apparatus as claimed in claim 10 in which said two channel ends are located close to each other.

Claim 15

Microwave drying apparatus as claimed in claim 10 in which said channel ends are located directly opposite from each other.

Claim 16

Microwave drying apparatus as claimed in claim 10 including control means operated by microwave energy transmitted through the said material to control the output of the microwave generator inversely relative to the level of the transmitted energy.

Claim 17

Microwave drying apparatus as claimed in claim 10 in which said channel ends are located directly opposite from each other whereby microwave energy transmitted through said material travels back through said channels, and control means operated by said transmitted energy to control the output of the microwave generator inversely relative to the level of the transmitted energy.

Claim 18

Microwave drying apparatus as claimed in claim 10 including microwave energy absorption means coupled to the other of said second pair of arms.

Claim 19

The microwave drying method which comprises dividing microwave energy from a microwave generator into two equal parts, and directing said energy parts through two separate channels to opposite sides of material to be dried, the distance of travel through one of said channels to the longitudinal center line of the material being equal to the distance of travel through the other of said channels to said center line plus a whole number of half wavelengths of the microwaves from said generator.

Claim 20

The microwave drying method which comprises dividing microwave energy from a microwave generator into two equal parts, and directing said energy parts through two separate channels to opposite sides of material to be dried, the distance of travel through one of said channels to the longitudinal center line of the material being equal to the distance of travel through the other of said channels to said center line plus a whole number of half wavelengths of the microwaves from said generator.

Claim 21

The method according to claim 16 in which said two microwave energy parts are directed by the channels to directly opposite areas on said material.

Claim 22

The method according to claim 16 including detecting the microwave energy transmitted through said material, and controlling the output of the microwave generator inversely relative to the level of the transmitted microwave energy.