(19)
(11) EP 0 792 085 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
12.04.2000 Bulletin 2000/15

(43) Date of publication A2:
27.08.1997 Bulletin 1997/35

(21) Application number: 97300635.6

(22) Date of filing: 31.01.1997
(51) International Patent Classification (IPC)7: H05B 6/70, H05B 6/78
(84) Designated Contracting States:
AT BE CH DE DK ES FI FR GB GR IE IT LI NL PT SE

(30) Priority: 23.02.1996 EP 96301230

(71) Applicants:
  • UNILEVER PLC
    London EC4P 4BQ (GB)

    GB IE 
  • UNILEVER N.V.
    3013 AL Rotterdam (NL)

    BE CH DE DK ES FI FR GR IT LI NL PT SE AT 

(72) Inventors:
  • Barratt, Lawrence
    Cambridge, Cambridgeshire CB5 8SE (GB)
  • Bows, John Richard
    Wellingborough,Northamptonshire NN10 8LP (GB)
  • Mullin, James Thomas
    Towcester, Northamptonshire NN12 6XP (GB)
  • Blindt, Renoo Avinash
    Wellingborough,Northamptonshire NN14 4DH (GB)
  • Crilly, James Francis
    West Clandon, Guildford GU14 7UE (GB)

(74) Representative: Mulder, Cornelis Willem Reinier, Dr. et al
Unilever PLC, Patent Division, Colworth House
Sharnbrook, Bedford MK44 1LQ
Sharnbrook, Bedford MK44 1LQ (GB)

   


(54) Apparatus & method for heating objects with microwaves


(57) An apparatus and method for heating planar and non-planar objects using microwaves, the method comprising: providing at least two beams of travelling microwaves from a coherent microwave source (4); directing each beam of travelling microwaves into separate arms (8,10) of a waveguide (6); isolating the beam of travelling microwaves in each arm using a microwave circulator (12); forming a standing wave from the travelling waves at the working area (14) where the arms meet; and varying the phase of at least one beam of travelling microwaves by altering the path length of the microwaves in the waveguide to move the standing wave. An object passing through the working area is irradiated by the microwaves, thereby generating complex interference patterns in the object. Controlling changes to the phases of the incident microwaves changes and controls the time-averaged superposition of the interference patterns, facilitating effective volumetric heating of the object.






Search report