Apparatus for improved cleaning using microwave energy

Abstract

The invention provides a cleaning apparatus which includes a tub which has a first circumscribing wall and a pair of opposed sidewalls positioned on a rotational axis, an enclosure defined within the first wall and the sidewalls, a drum positioned inside the enclosure, and which includes a second circumscribing wall, a pair of opposed end walls positioned on the rotational axis, a cavity defined within the second wall and the end walls, into which an item to be cleaned is placed, and a drive means which is connected to the drum to provide rotational movement to the drum about the axis, characterized in that the cleaning apparatus includes a plurality of microwave generators, each of which is adapted to direct microwaves into the cavity.

1 . A cleaning apparatus which includes a tub which has a first circumscribing wall and a pair of opposed sidewalls positioned on a rotational axis, an enclosure defined within the first wall and the sidewalls, a drum positioned inside the enclosure and which includes a second circumscribing wall, a pair of opposed end walls on the rotational axis, a cavity defined within the second wall and the end walls, into which an item to be cleaned is placed, a drive means which is connected to the drum to provide rotational movement to the drum about the axis, characterized in that the cleaning apparatus includes a plurality of microwave generators, each of which is adapted to direct microwaves into the cavity. 
     
     
         2 . A cleaning apparatus according to  claim 1  wherein the drum is a cylindrical or a tubular polygonal drum. 
     
     
         3 . A cleaning apparatus according to  claim 1  wherein the tub has an aperture through a sidewall and the drum has an opening through an end wall that is in register with the aperture. 
     
     
         4 . A cleaning apparatus according to claim wherein each microwave generator is a magnetron or a solid-state microwave module. 
     
     
         5 . A cleaning apparatus according to  claim 1  wherein the plurality of microwave generators is connected or engaged to the first wall of the tub or the second wall of the drum, with each generator being positioned thereon to introduce microwaves in a radial direction into the cavity. 
     
     
         6 . A cleaning apparatus according to  claim 1  wherein the plurality of microwave generators constitutes a first array in which the generators are spaced in a direction of the rotational axis to position each generator to radiate microwave energy across a respective circumferential segment of the first wall of the tub or the second wall of the drum. 
     
     
         7 . A cleaning apparatus according to  claim 6  wherein each circumferential segment is irradiated by one generator each. 
     
     
         8 . A cleaning apparatus according to  claim 7  wherein the generators are axially aligned, radially offset or circumferentially opposed. 
     
     
         9 . A cleaning apparatus according to  claim 1  wherein the plurality of microwave generators constitutes a plurality of generator arrays in which each array provides more than one generator positioned to radiate microwave energy across a respective circumferential segment. 
     
     
         10 . A cleaning apparatus according to  claim 9  wherein the generators in each generator array are axially aligned or radially offset relatively to the other generators in the respective array. 
     
     
         11 . A cleaning apparatus according to  claim 1  wherein at least one of the microwave generators is connected or engaged to a side wall of the tub or an end wall of the drum to introduce microwaves in an axial direction into the cavity. 
     
     
         12 . A cleaning apparatus according to  claim 11  wherein each microwave module has, or is connected to, at least one output or antenna which is positioned to radiate microwave energy into the cavity. 
     
     
         13 . A cleaning apparatus according to  claim 12  wherein the at least one microwave generator is connected or engaged to a side wall of the tub or an end wall of the drum has a radiating patch antenna. 
     
     
         14 . A cleaning apparatus according to  claim 13  wherein the radiating patch antenna is connected to an end wall of drum in a co-axial position relatively to a shaft of the drive means. 
     
     
         15 . A cleaning apparatus according to  claim 1  wherein the drum is made of a material transparent to microwave energy. 
     
     
         16 . A cleaning apparatus according to  claim 1  wherein the drum is made of a microwave impermeable material. 
     
     
         17 . A cleaning apparatus according to  claim 16  wherein the drum includes a plurality of microwave transparent windows through the second wall or an end wall. 
     
     
         18 . A cleaning apparatus according to  claim 17  wherein the transparent windows are positioned on the second wall to be enabled to rotate into a radially co-incident position with a respective generator. 
     
     
         19 . A cleaning apparatus according to  claim 1  wherein the plurality of microwave generators produces an aggregate microwave output power of 1 KW to 50 kW. 
     
     
         20 . A cleaning apparatus according to  claim 1  wherein each microwave energy generator is adapted to emit a continuous or a pulsed microwave power output. 
     
     
         21 . A cleaning apparatus according to  claim 1  wherein each microwave energy generator is adapted to emit microwaves in a range 300 MHZ to 30 GHZ. 
     
     
         22 . A cleaning apparatus according to  claim 1  which includes a control circuit to which the plurality of microwave generators is connected to control a microwave power output of the plurality of microwave generators in terms of one or more of the following parameters: power output, phase, frequency and duty cycle. 
     
     
         23 . A cleaning apparatus according to  claim 22  wherein the control circuit includes a programmable process controller and one or more sensors connected to the controller and adapted to measure one or more of the following: relative rotational position of the drum, water temperature in the cavity, microwave field strength and microwave reflection coefficient sensor. 
     
     
         24 . A cleaning apparatus according to  claim 23  wherein at least one of the sensors is a shaft encoder which provides input to the controller as to the position of a plurality of microwave transparent windows. 
     
     
         25 . A cleaning apparatus according to  claim 24  wherein the controller is adapted to receive input from the shaft controller to ensure that a generator only radiates microwaves when a transparent window is radially co-incident with the generator. 
     
     
         26 . A cleaning apparatus according to  claim 25  wherein the controller is adapted to receive input from the shaft controller, and input as to whether the drum is not rotating or is rotating, to ensure that the respective microwave generator only radiates microwaves when no items to be cleaned lie adjacent a transparent window or only when the items to be cleaned lie adjacent a transparent window respectively or when items to be cleaned.