ELECTRONIC DRYER

• US 3,854,219 A
• Filed: 06/18/1973
• Issued: 12/17/1974
• Est. Priority Date: 06/18/1973
• Status: Expired due to Term

• Current Assignee: James E. Staats
• Original Assignee: James E. Staats
• Inventors: Staats, James E.
• Primary Examiner(s): Myhre, Charles J.
• Assistant Examiner(s): Devinsky, Paul
• Application Number:
  US05/370,863
• Time in Patent Office: 547 Days
• Field of Search: 34/1,17,48,55,68,133 219/10.55
• US Class Current: 34/265
• CPC Class Codes: D06F 58/02 having dryer drums rotating about a horizontal axis
• CPC Class Codes: D06F 58/266 Microwave heating equipment
• CPC Class Codes: F26B 3/34 by using electrical effects

Abstract

A dryer includes a cabinet having a drying chamber mounted therein. A blower connected by a duct to the drying chamber draws air through the chamber from openings provided in both the chamber and the cabinet. The output of a source of microwave energy is introduced into the duct which functions as a waveguide to direct the microwave energy to the drying chamber. As the microwave energy heats and causes to vaporize the water in the articles to be dried, the evaporated moisture is drawn out of the chamber by the air flowing therethrough and is exhausted to atmosphere. In one embodiment, the dryer is formed as a clothes dryier wherein the drying chamber takes the form of a rotating tumbling drum mounted within the cabinet and the air entering the drum is preheated.

Claims

1. An electronic fabric dryer comprising:

a cabinet having a microwave impermeable drying chamber therein for accommodating fabrics to be dried;

generating means including a magnetron for producing microwave energy at a predetermined ultra-high frequency;

air circulating means associated with said drying chamber for circulating a stream of air therethrough;

a conduit coupling said circulating means with said drying chamber thereby serving as an air duct, said conduit also serving as a waveguide to conduct said microwave energy to said drying chamber;

an air inlet disposed upstream of said magnetron such that said air stream serves to cool said magnetron while said magnetron serves to preheat said air stream;

a heat source disposed in said air stream upstream of said drying chamber for further heating said preheated air stream before it enters said drying chamber thereby serving to accelerate the drying process;

output means coupling said magnetron with said conduit for transmitting energy from said magnetron to said conduit, whereby moisture from said fabrics is heated and vaporized by said microwave energy and by said preheated air stream and is carried from said drying chamber by said air stream; and

control means associated with said generating means and said heat source, the control means being responsive to the moisture content of said fabrics to interrupt the transmission of microwave energy into said drying chamber and to interrupt the supply of heat to said air stream when said fabrics have reached a predetermined degree of dryness.

2. The invention of claim 1 wherein said heat source comprises an electric resistance heating element.

3. An electronic clothes dryer comprising:

a cabinet having a microwave impermeable drying chamber therein for accommodating clothes to be dried;

generating means including a magnetron for producing microwave energy at a predetermined ultrahigh frequency;

a blower associated with said drying chamber for circulating a stream of air therethrough;

a conduit coupling said blower with said drying chamber, the conduit thereby serving as an air duct;

an air inlet associated with said cabinet and disposed upstream of said magnetron such that said airstream serves to cool said magnetron while said magnetron serves to preheat said air stream;

a heat source disposed in said air stream upstream of said drying chamber for further heating said preheated air stream before it enters said drying chamber;

output means including a pair of output terminals associated with said magnetron and a coaxial transmission line coupled therewith, an antenna means, the free end of the coaxial transmission line being coupled with the antenna means, the antenna means being insulated from said conduit and positioned to radiate microwave energy into said conduit, said conduit serving as a waveguide to conduct said radiated microwave energy to said drying chamber in a direction opposite to the flow of air therethrough; and

control means associated with said generating means and said heat source, the control means being responsive to thE moisture content of said clothes to interrupt the transmission of microwave energy into said drying chamber and to interrupt the supply of heat to said air stream when said clothes have reached a predetermined degree of dryness.

4. The invention of claim 3 further including a microwave reflector disposed in said conduit between said blower and said antenna means to prevent the transmission of microwave energy to said blower.

5. The invention of claim 3 wherein:

said cabinet has an access aperture spaced apart from said air inlet the access aperture communicating with said drying chamber, and said conduit having one end thereof terminating adjacent the access aperture;

a hollow microwave impermeable door movable between a closed position and an open position is provided to control access to said drying chamber through said access aperture, the door having first and second openings therein providing communication with the hollow interior thereof, the first opening having a microwave window therein for accomodating transmission of microwave energy therethrough into said drying chamber, the first opening also including a plurality of perforations impermeable to microwave energy but allowing the free flow of air therethrough, the door in the closed position thereof placing the second opening in registry with the free end of said conduit to provide a path for the stream of air from the atmosphere to said inlet and said drying chamber and said hollow door and said conduit and said blower and further to provide a path for microwave energy from said magnetron through said conduit and said hollow door and said microwave window into said drying chamber.

6. The invention of claim 5 wherein said microwave window comprises a generally cross-shaped opening in said door, the microwave window having a cover associated therewith overlying the cross-shaped opening, the cover being transparent to microwave energy while preventing the passage of fabric through the opening into the hollow interior of said door.

7. The invention of claim 6 wherein said drying chamber comprises a generally cylindrical metallic drum mounted for rotation about a substantially horizontal axis, the drum having an air ingress and an access aperture at spaced-apart points thereof, said air ingress being impermeable to microwave energy but allowing the free flow of air therethrough.

8. The invention of claim 7 further including an electrically conductive door seat mounted adjacent said access aperture such that the door seat overlaps said door in the closed position thereof a distance corresponding to one-fourth of the wave length of said predetermined ultrahigh frequency thereby providing a choke joint to prevent the escape of microwave energy from said cabinet.

9. The invention of claim 3 wherein said control means comprises a power supply, a relay having a pair of contacts coupled in series with an input of the power supply and a coil winding coupled in series between an output of the power supply and an input of said magnetron, the relay being responsive to the current through the input of said magnetron for opening the contacts and de-energizing the power supply and said magnetron and said heat source when the current through the input of said magnetron reaches a predetermined value as the result of the drying of the wet fabric to a predetermined degree of dryness.