Turntable incorporating heating means and oven incorporating the same

1. An oven comprising an oven cavity, a main heating means for heating a food item, and a turntable arranged in a lower region of the oven cavity and comprising a surface for heating a food item ( 27 , 75 ) placed on the turntable ( 19 ), wherein the turntable ( 19 ) is provided with integral electrical heating means ( 29 ) and with electrically-conductive means for connecting the integral electrical heating means to a source of electrical power.

2. An oven as claimed in claim 1 , wherein the heating means ( 29 ) comprises an elongate electrically conducting material embedded into the turntable.

3. An oven as claimed in claim 2 , wherein the heating means is embedded into a lower surface of the turntable.

4. An oven as claimed in claim 1 , wherein the heating means comprises a thick film heating element.

5. An oven as claimed in claim 4 , wherein the thick film heater is applied to an underside of the turntable.

6. An oven as claimed in claim 4 , wherein the thick film heater is applied to an upper surface of the turntable.

7. An oven as claimed in claim 1 , wherein the heating means comprises a heating element wrapped around an insulating board.

8. An oven as claimed in claim 7 , wherein the board comprises mica.

9. An oven as claimed in claim 1 , wherein a layer of thermal insulation material ( 31 ) is included on a lower surface of the turntable.

10. An oven as claimed in claim 1 , wherein the heating means comprises a heating element ( 49 ) provided within a dish-like support ( 45 ) containing a base layer ( 47 ) of thermal insulation material.

11. An oven as claimed in claim 10 , wherein the base layer ( 47 ) comprises microporous thermal and electrical insulation material.

12. An oven as claimed in claim 10 , wherein the heating element ( 49 ) is supported relative to the base layer.

13. An oven as claimed in claim 12 , wherein the heating element ( 49 ) comprises a corrugated metal ribbon mounted edgewise on the base layer ( 47 ) and secured by partial embedding.

14. An oven as claimed in claim 12 , wherein the heating element ( 49 ) comprises means selected from a coiled wire and a coiled ribbon secured to the base layer ( 47 ).

15. An oven as claimed in claim 12 , wherein the heating element ( 49 ) comprises a lamp mounted above the base layer ( 47 ).

16. An oven as claimed in claim 12 , wherein the heating element ( 49 ) comprises a sheathed heating element.

17. An oven as claimed in claim 12 , wherein the heating element ( 49 ) comprises a resistance element mounted within a glass tube.

18. An oven as claimed in claim 10 wherein a peripheral wall ( 51 ) of thermal insulation material is included extending around the internal periphery of the dish-like support ( 45 ).

19. An oven as claimed in claim 1 , wherein the heating power output of the heating means ( 29 ) increases with increasing distance from an axis of rotation of the turntable.

20. An oven as claimed in claim 1 wherein conductive tracks ( 35 , 37 ) connected to the heating means are included for supplying power to the heating means.

21. An oven as claimed in claim 20 , wherein the conductive tracks ( 35 ) are in the form of annular tracks provided on an underside of the turntable ( 19 ).

22. An oven as claimed in claim 20 , wherein the conductive tracks ( 37 ) are provided around the periphery of a support shaft ( 41 ) provided on an underside of the turntable ( 19 ).

23. An oven as claimed in claim 1 , wherein the main heating means comprises a magnetron ( 23 ).

24. An oven as claimed in claim 1 , wherein the main heating means comprises a resistance heating element ( 71 ) and fan means ( 73 ) for propelling air past the heating element ( 71 ) and into the oven cavity ( 67 ).

25. An oven as claimed in claim 24 , wherein the main heating means further comprises a grill element ( 77 ) for directing radiation downwardly towards the food item.

26. An oven as claimed in claim 24 , wherein the main heating means further comprises a grill element for directing radiation downwardly towards the food item.