(19)
(11) EP 0 348 156 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
27.11.1991 Bulletin 1991/48

(43) Date of publication A2:
27.12.1989 Bulletin 1989/52

(21) Application number: 89306233.1

(22) Date of filing: 20.06.1989
(51) International Patent Classification (IPC)4: B65D 81/34, H05B 6/64
(84) Designated Contracting States:
AT BE CH DE ES FR GB IT LI LU NL SE

(30) Priority: 22.06.1988 CA 570096

(71) Applicant: ALCAN INTERNATIONAL LIMITED
Montreal Quebec H3A 3G2 (CA)

(72) Inventors:
  • Hewitt, Bryan Cobley
    Kingston Ontario K7M 6G7 (CA)
  • Ball, Melville Douglas
    Kingston Ontario K7M 1E1 (CA)

(74) Representative: Boydell, John Christopher et al
Stevens, Hewlett & Perkins 1 Serjeants' Inn Fleet Street
London EC4Y 1LL
London EC4Y 1LL (GB)


(56) References cited: : 
   
       


    (54) Improvements relating to microwave heating


    (57) A container (10) for heating a substance, e.g. food, in a microwave oven has a bottom (12) transparent to microwave energy. The container is supported on a stand (22) that contains one or more electrically conductive plates (32) (or apertures in an electrically conductive sheet) that generate at least one mode of microwave energy of higher order than the fundamental modes. The stand (22) also serves to support the container (10) above the higher order mode generating plates (or apertures) so that the undersurface of the substance is spaced from them by a uniform predetermined distance. The arrangement has the known features of "bottom heating", i.e. taking advantage of the natural heat flow in the substance, while achieving more uniform heating of the substance by virtue of the higher order mode or modes. As an alternative to or in addition to the generation of higher order modes, the stand may embody elements that modify the microwave pattern in a manner that enhances the coupling of microwave energy into the undersurface of the substance to be heated.






    Search report