Apparatus for and a method of microwave heating of rotatable articles, especially green tyre blanks

A method of microwave heating of rotatable articles by at least one microwave radiation source (12) in a heating chamber (5) configured to receive a rotatable article, wherein each microwave radiation source (12) is connected to the heating chamber (5) via at least one wave guide (11) having at least one inlet in a lateral wall of the heating chamber (5), wherein the rotatable article comprises a material absorbing microwave radiation,

• wherein direct and selective heating of a heated portion (3) of the rotatable article is performed in a heating space defined by at least one inlet of the wave guide (11) in the lateral wall of the heating chamber (5), the heated portion (3) of the rotatable article and at least two covers (6) arranged one above another and in the form of an area defined by an inner and outer circumference,
• wherein at least one cover (6) is vertically slidable relative to the lateral wall of the heating chamber (5) such that the covers (6) prevent microwave radiation to propagate outside the heating space in the vertical direction, wherein the non-heated portions (4) of the rotatable article outside the heating space are not directly heated,
• wherein at least one cover (6) is vertically slidable relative to the lateral wall of the heating chamber (5) by a lifting mechanism (27).

An apparatus for microwave heating of rotatable articles, comprising at least one microwave radiation source (12), at least one wave guide (11) and a heating chamber (5) for receiving a rotatable article, wherein the rotatable article comprises a material absorbing microwave radiation,

• wherein each microwave radiation source (12) is connected to the heating chamber (5) via at least one wave guide (11) having at least one inlet in a lateral wall of the heating chamber (5),
• wherein the heating chamber (5) comprises at least two covers (6) arranged one above another and in the form of an area defined by an inner and outer circumference, wherein the covers (6) comprise an opening in the middle, wherein the covers (6) are configured to define a heating space between at least one inlet of the wave guide (11) in the lateral wall of the heating chamber (5) and the heated portion (3) of the rotatable article, and are further configured to prevent microwave radiation from propagating outside the heating space in the vertical direction,
• wherein at least one cover (6) is vertically slidable relative to the lateral wall of the heating chamber (5) by a lifting mechanism (27).