Method of and apparatus for heating of dielectric materials in a microwave field

Claim 1

A method of heating, particularly dielectric materials by exposing them to the electromagnetic energy of a microwave field in a waveguide which is energized by a microwave generator and short-circuited at one end, comprising the steps of heating by microwave energy dielectric material in a waveguide made of a solid dielectric nonmetallic material and containing a channel extending through its entire length, using said channel for shaping and calibrating the dielectric material during the process of heating, and passing said dielectric material to be heated through said channel so as to fill said channel in cross section, passing microwave energy from said microwave generator into said waveguide and through said waveguide in a first direction, said microwave energy reaching said short-circuited one end, reflecting said microwave energy reaching said short-circuited one end back through said waveguide, continuously conveying axially through the waveguide in said first direction of energy flux said dielectric material to be heated, attenuating said reflected microwave energy by further heating therewith said dielectric material in a direction reverse to said first direction sufficiently such that said microwave generator is not adversely affected, and shielding said waveguide against radiant heat loss.

Claim 2

A method of heating, particularly dielectric materials by exposing them to the electromagnetic energy of a microwave field in a waveguide which is energized by a microwave generator and short-circuited at one end, comprising the steps of heating by microwave energy dielectric material in a waveguide made of a solid dielectric nonmetallic material and containing a channel extending through its entire length, using said channel for shaping and calibrating the dielectric material during the process of heating, and passing said dielectric material to be heated through said channel so as to fill said channel in cross section, passing microwave energy from said microwave generator into said waveguide and through said waveguide in a first direction, said microwave energy reaching said short-circuited one end, reflecting said microwave energy reaching said short-circuited one end back through said waveguide, continuously conveying axially through the waveguide in said first direction of energy flux said dielectric material to be heated, attenuating said reflected microwave energy by further heating therewith said dielectric material in a direction reverse to said first direction sufficiently such that said microwave generator is not adversely affected, and shielding said waveguide against radiant heat loss.

Claim 3

An apparatus for heating, particularly dielectric materials by exposing them to the electromagnetic energy of a microwave field in a waveguide which is energized by a microwave generator comprising a waveguide made of a solid dielectric nonmetallic material and having a channel extending through its entire length for continuously conveying therethrough a dielectric material to be heated passing therethrough filling the cross section of said channel, means for coupling microwave energy from said microwave generator into said waveguide adjacent one end thereof, first conduit means for passing said dielectric material to be heated into said one end of said waveguide and into said channel thereof, said waveguide being short-circuited at its other end and oriented to reflect microwave energy reaching said other end back through said waveguide, second conduit means communicating with said waveguide channel at said other end for removing said dielectric material from said waveguide, and the length of said waveguide being such, that the electromagnetic energy which arrives at the short-circuited end of said waveguide and which has not been converted to heat in the dielectric material during its passage through the waveguide is reflected at said short-circuited end and passes through said waveguide a second time to be sufficiently attenuated by further heating of said dielectric material that the feeding microwave generator is not adversely affected or damaged.

Claim 4

An apparatus for heating, particularly dielectric materials by exposing them to the electromagnetic energy of a microwave field in a waveguide which is energized by a microwave generator comprising a waveguide made of a solid dielectric nonmetallic material and having a channel extending through its entire length for continuously conveying therethrough a dielectric material to be heated passing therethrough filling the cross section of said channel, means for coupling microwave energy from said microwave generator into said waveguide adjacent one end thereof, first conduit means for passing said dielectric material to be heated into said one end of said waveguide and into said channel thereof, said waveguide being short-circuited at its other end and oriented to reflect microwave energy reaching said other end back through said waveguide, second conduit means communicating with said waveguide channel at said other end for removing said dielectric material from said waveguide, and the length of said waveguide being such, that the electromagnetic energy which arrives at the short-circuited end of said waveguide and which has not been converted to heat in the dielectric material during its passage through the waveguide is reflected at said short-circuited end and passes through said waveguide a second time to be sufficiently attenuated by further heating of said dielectric material that the feeding microwave generator is not adversely affected or damaged.