Microwave applicator for continuous press

Claim 1

An apparatus for the simultaneous application of pressure and microwaves to curable assemblies comprising: a continuous press including two endless metal press belts forming a nip region, the press belts being disposed to apply pressure to curable assemblies inserted therebetween, and including an inlet and an outlet for the passage of curable assemblies, a press chamber defined by the two belt surfaces and by two side walls, means to apply microwaves to the curable assemblies from at least one microwave generator through a waveguide forming an interface with the press chamber located in an opening in at least one of said side walls, said waveguide spanning substantially the entire vertical spacing between said belts dam means at the interface between the waveguide and the press chamber to provide a solid interface between said curable assembly and said waveguide to withstand the lateral pressure exerted thereon by curable assemblies being pressed, and which effectively permits propagation of microwaves into the press chamber said microwaves having an electric vector substantially normal to the plane of said press belts, said dam means being selected from the group consisting of a solid ceramic member and a reinforced member containing spaced metal elements normal to the electric vector of the microwave field, said waveguide being positioned from the near-edge of the curable assembly at a distance sufficient to permit substantial equalization of fringing electric fields, and said waveguide including a 1/4 wave choke adjacent each moving belt for effectively establishing the point of contact between the waveguide and the press belts at a point (2n+1) (wavelength of the microwave energy being used)/4, from the microwave path entrance to the wave choke, where n is an integer.

Claim 2

An apparatus for the simultaneous application of pressure and microwaves to curable assemblies comprising: a continuous press including two endless metal press belts forming a nip region, the press belts being disposed to apply pressure to curable assemblies inserted therebetween, and including an inlet and an outlet for the passage of curable assemblies, a press chamber defined by the two belt surfaces and by two side walls, means to apply microwaves to the curable assemblies from at least one microwave generator through a waveguide forming an interface with the press chamber located in an opening in at least one of said side walls, said waveguide spanning substantially the entire vertical spacing between said belts dam means at the interface between the waveguide and the press chamber to provide a solid interface between said curable assembly and said waveguide to withstand the lateral pressure exerted thereon by curable assemblies being pressed, and which effectively permits propagation of microwaves into the press chamber said microwaves having an electric vector substantially normal to the plane of said press belts, said dam means being selected from the group consisting of a solid ceramic member and a reinforced member containing spaced metal elements normal to the electric vector of the microwave field, said waveguide being positioned from the near-edge of the curable assembly at a distance sufficient to permit substantial equalization of fringing electric fields, and said waveguide including a 1/4 wave choke adjacent each moving belt for effectively establishing the point of contact between the waveguide and the press belts at a point (2n+1) (wavelength of the microwave energy being used)/4, from the microwave path entrance to the wave choke, where n is an integer.

Claim 17

A method for simultaneously exposing a curable assembly to pressure and microwaves comprising steps of: continuously advancing a curable assembly between metal press belts of a continuous press through a press chamber region wherein two side walls bridge the gap between the press belts to prevent lateral expansion of the curable assembly under compression, directing microwaves having an electric vector substantially normal to the plane of said press belts into the curable assembly in the press chamber region through a waveguide positioned in at least one of said side walls and oriented in a direction substantially parallel to the planes of the press belts, said waveguide spanning substantially the entire vertical spacing between said belts, wherein a microwave transparent dam is provided at the interface between the waveguide and the press chamber to provide a solid interface between said curable assembly and said waveguide to withstand the lateral pressure exerted thereon by curable assemblies being pressed, positioning the metal portions of said waveguide at a sufficient distance from said curable assembly to substantially equalize fringing electric fields before the microwaves reach the curable assembly, avoiding arcing between the belts and the waveguide with 1/4 wave traps integral with said waveguides adjacent each said moving belt, for effectively establishing the point of contact between the waveguide and the press belts at a point (2n+1) (wavelength of the microwave energy being used)/4, from the microwave path entrance to the wave trap, where n is an integer and removing the curable assembly from the continuous press after the curable assembly has been exposed to microwaves sufficient to effect cure.

Claim 18

A method for simultaneously exposing a curable assembly to pressure and microwaves comprising steps of: continuously advancing a curable assembly between metal press belts of a continuous press through a press chamber region wherein two side walls bridge the gap between the press belts to prevent lateral expansion of the curable assembly under compression, directing microwaves having an electric vector substantially normal to the plane of said press belts into the curable assembly in the press chamber region through a waveguide positioned in at least one of said side walls and oriented in a direction substantially parallel to the planes of the press belts, said waveguide spanning substantially the entire vertical spacing between said belts, wherein a microwave transparent dam is provided at the interface between the waveguide and the press chamber to provide a solid interface between said curable assembly and said waveguide to withstand the lateral pressure exerted thereon by curable assemblies being pressed, positioning the metal portions of said waveguide at a sufficient distance from said curable assembly to substantially equalize fringing electric fields before the microwaves reach the curable assembly, avoiding arcing between the belts and the waveguide with 1/4 wave traps integral with said waveguides adjacent each said moving belt, for effectively establishing the point of contact between the waveguide and the press belts at a point (2n+1) (wavelength of the microwave energy being used)/4, from the microwave path entrance to the wave trap, where n is an integer and removing the curable assembly from the continuous press after the curable assembly has been exposed to microwaves sufficient to effect cure.