the baking oven , which is designated in its entirety by the reference numeral 1 in fig1 comprises a oven casing 2 of a square base of 1 m 2 and a height of approximately 2 m . dough pieces 3 , for instance deep frozen or partially defrosted rolls , are fed into the interior of the baking oven 1 via an inlet 4 that can be closed by a loading door 5 which is preferably manually operated and shuts tightly . the inlet 4 is followed by a doorway 6 that leads to an annular baking chamber 7 , the diameter of which increases upwards . the baking chamber 7 is rotationally symmetrical and defined outwards by a funnel - shaped , outer wall 8 that expands upwardly . the baking chamber 7 is defined inwards by a conical inner wall 9 that expands upwards in cross - sectional shape . the baking chamber 7 and the walls 8 , 9 have a joint , vertical axis of symmetry 10 . the inner wall 9 is supported by a holding bar 11 which extends centrally along the axis of symmetry 10 , the holding bar 11 being carried by a holding plate 12 which is disposed above the doorway 6 in the oven casing 2 . the outer wall 8 is rotatable about the axis of symmetry 10 . to this end , it is mounted in the vicinity of the bottom of the baking chamber 7 by three ball bearings which are regularly distributed around the axis of symmetry 10 in the circumferential direction , forming a first radial bearing 13 for the outer wall 8 . the first radial bearing 13 as well as the bearings described below are illustrated only diagrammatically in the drawing . on the side of the casing , the first radial bearing 13 is mounted on a first intermediate bottom 14 in the oven casing 2 . in the upper part of the baking chamber 7 , above a horizontal boundary wall 15 of the inner wall 9 , the outer wall 8 is connected to an inner bearing sleeve 17 by way of three cross struts 16 that are regularly distributed in the circumferential direction , the sleeve 17 rotarily enclosing the holding bar 11 . the inner bearing sleeve 17 is housed in an outer bearing sleeve 20 for rotation about the axis of symmetry 10 by way of a second radial bearing 18 , which is an encircling ball bearing , and an axial / radial bearing 19 , which comprises two encircling ball bearings . the sleeve 20 is tightly joined to a second intermediate bottom 21 , disposed above the cross struts 16 , of the baking oven 1 . the inner bearing sleeve 17 supports a horizontal driving pulley 22 that encloses the holding bar 11 and can be driven via a v belt 23 by a driving motor ( not shown ). the driving motor serves for rotation of the outer wall 8 of the baking chamber 7 about the axis of symmetry 10 . the baking chamber 7 is defined downwards by a baking - chamber closing arrangement 24 with a cylindrical jacket wall 25 that is covered upwards by a convex grid 26 . the baking - chamber closing arrangement 24 is displaceable between a baking position seen in fig2 and a position for discharge seen in fig3 . via a joining element 27 and a slide rod 28 , the jacket wall 25 is connected to a lifting cylinder 29 which is supported by a third baking - oven - 1 intermediate bottom 30 which is disposed below the baking - chamber closing arrangement 24 and heat - insulated . in the baking position , the outer peripheral area of the grid 26 of the baking - chamber closing arrangement 24 bears directly against a funnel - shaped baffle 31 that is mounted on the bottom end of the inner wall 9 . the baking chamber 7 is heated by heated circulating air that is generated by a fan 32 with an electric heating element 33 ; the fan 32 is supported by the second intermediate bottom 21 . circulating air heated by the heating element 33 passes through a first circulating - air guiding channel section 34 which is formed between a lateral inside casing wall 35 and a baking - chamber - casing wall 36 that envelops the outer wall 8 . as roughly outlined in fig2 by arrows of flow direction 37 , the circulating air passes from the first circulating - air guiding channel section 34 into a circulating - air collecting chamber 38 that is disposed between the first intermediate bottom 14 and the third intermediate bottom 30 . the circulating air passes from the circulating - air collecting chamber 38 into the baking - chamber closing arrangement 24 that is open downwardly , from where it flows through the grid 26 and , guided by the baffle 31 , through holes in the baffle 31 and into the inner wall 9 . passages in the inner wall 9 admit the circulating air to the baking chamber 7 , which is shown in fig2 by the arrow of flow direction 39 . the holes in the baffle 31 and the passages in the inner wall 9 are not shown in the drawing . the circulating air leaves the baking chamber 7 via a second circulating - air guiding channel section 40 in a direction towards the fan 32 . [ 0027 ] fig3 illustrates the baking - chamber closing arrangement 24 in a position for discharge , in which it is displaced downwards , as against the baking position , by the aid of the lifting cylinder 29 . this leaves open an aperture 41 in the first intermediate bottom 14 of the baking chamber 7 . the round aperture 41 connects the baking chamber 7 to an unloading passageway 42 that has a slope 44 towards an outlet 43 . the outlet 43 can be shut by a motor pivoted unloading door 45 . a baked - article collecting box 46 is disposed below the outlet 43 . the loading door 5 is opened for the baking oven 1 to be loaded with a charge of for example 45 rolls . at this time , the baking - chamber closing arrangement 24 is in the baking position . then the dough pieces 3 are led into the baking oven 1 , sliding through the doorway 6 into the baking chamber 7 and collecting on the bottom of the baking chamber 7 that is closed by the closing arrangement 24 . then the outer wall 8 is set rotating by the driving motor and the fan 32 and the heating element 33 are activated . by reason of the centrifugal force occasioned by rotation of the outer wall 8 , the dough pieces 3 are distributed uniformly on the outer wall 8 and within the baking chamber 7 . simultaneously , the dough pieces 3 are heated and baked by the heated circulating air that passes through the baking chamber 7 . after termination of the baking process , rotation of the outer wall 8 is stopped or distinctly reduced for the baked dough pieces 3 to collect on the bottom of the baking chamber 7 under the action of gravity . with the aid of the lifting cylinder 29 , the baking - chamber closing arrangement 24 is moved by timed actuation into the position for discharge of fig3 . simultaneously the unloading door 45 opens by timed control . the baked dough pieces 3 leave the baking chamber 7 through the aperture 41 under the action of gravity , sliding along the slope 44 towards the outlet 43 and falling through it into the baked - article collecting box 46 . the baking time is approximately 12 minutes . an embodiment ( not shown ) of the baking oven 1 additionally comprises a vacuum pump by which to set given negative pressure in the baking chamber 7 . simultaneously , this embodiment of the baking oven 1 includes a steaming assembly , known per se , by which to supply water vapor to the baking chamber 7 . in this embodiment , the baking chamber 7 is evacuated by the vacuum pump at the beginning of the baking process so that the dough pieces 3 in the baking chamber can be heated more rapidly by the circulating air . interaction of the vacuum pump and the steaming assembly helps obtain more efficient humidification of the dough pieces by steam . in keeping with another embodiment ( not shown ) of the baking oven , the job of opening and closing the loading door 5 is controlled automatically .
a baking oven comprises a charging section with an inlet for dough pieces to be loaded ; a baking chamber ; and a discharging section with an outlet for baked dough pieces to be unloaded . provision is made for a circulating - air arrangement with a source that generates a flow of circulating air , a circulating - air heating device , and a circulating - air guiding channel , sections of which are formed by the baking chamber . an outer wall of the baking chamber is rotationally symmetrical about a vertical axis of rotation , expanding steadily upwards in particular in the shape of a funnel . a baking oven results , in which the dough pieces can be moved and distributed as regularly as possible during baking .