GB2146222A - Bakery oven - Google Patents

Abstract

In a known method of baking, for example, bread, the dough pieces are subjected to a steamy atmosphere, caused by injection of steam from a boiler into the oven, in order to cause glazing of the top of the loaf, to reduce splitting of the top of the loaf and to reduce the springiness of the loaf. In order to reduce the running costs of the oven, in accordance with the invention, atomisers are fitted in the oven and liquid water is fed to the atomisers to create the steamy atmosphere in the oven. Preferably, the atomisers are of the type which are fed not only with liquid water but also with compressed air which causes the atomisation of the water.

Description

SPECIFICATION Bakery oven This invention relates to bakery ovens.

In a known bakery installation, moulded dough pieces, after having been finally proved, are baked in tins in an oven for about 20 or 25 minutes. During the first 5 minutes that each dough piece is in the oven, it is subjected to a steamy atmosphere, caused by injection into the oven of steam which has been generated in a boiler. The purpose of the steam injection is three-fold: firstly, it causes the top of the loaf to glaze; secondly, it prevents or reduces breaking or splitting of the top of the loaf; and, thirdly, it reduces the springiness of the loaf and thus makes the loaf easier to cut and spreading of the slices easier. The use of steam injection does, however, have a disadvantage in that the energy required to heat the boiler to produce the steam adds to the running cost of the installation.

In accordance with the present invention, there is provided a bakery oven having means within the oven enclosure to atomise liquid water and means to feed liquid water to the atomising means for atomisation.

A specific embodiment of the present invention will now be described by way of example with reference to the accompanying drawing, which is a schematic sectional side view of an entrance portion of a bakery oven. Referring to the drawing, a travelling bakery oven has a heated entrance zone 10 into which proved dough pieces 1 2 are fed on a conveyor 14, each dough piece 1 2 being in a baking tin 1 6. A vertically slidable door 18 is provided at the entrance to the oven and a further such door 20 is provided downstream of the door 1 8. The doors are adjusted so that their lower edges are just clear of the dough pieces, and the lower edges may be provided with downwardly extending flexible lightweight flaps (not shown).The speed of the conveyor 14 is set so that each dough piece takes about 5 minutes to pass from door 1 8 to door 20, and the dough pieces then continue on the conveyor for baking in the main portion 22 of the oven for about 1 5 or 20 minutes.

Two rows 24, 26 downwardly-directed atomiser nozzles 28 are mounted in the roof of the entrance zone 10 of the oven, each row 24, 26 extending transversely across the oven. Each nozzle 28 is fed with water, which is not previously heated, via a pipe 30 and with compressed air via a pipe 32 to produce a fog of atomised water to be discharged from the nozzle.

The nozzles may be of the type sold under the trade name SONICORE by Ultrasonics Limited of Shipley, West Yorkshire. The compressed air fed to the nozzle is caused by a resonator chamber in the nozzle to form a standing shock wave. The water fed to the nozzle is caused by the shock wave to be shattered into droplets which are discharged from the nozzle.

Although the discharged droplets will take heat from the oven in warming to the oven temperature, it is believed that there will be a substantial saving in energy compared with known ovens into which live steam is injected.

A sketch costing for a typical bakery oven installation suggested that that oven would cost about 1 5000 less per year to run for a capital outlay of about 3000 or 4000 to convert the oven from using live steam injection to using water atomisers as described above.

The invention may be applied to other types of bakery oven, for example rotary ovens in which the dough pieces are revolved on racks inside the oven enclosure.

Also, the oven may be used for baking other bakery products which in the past have been subjected to a steamy atmosphere in the oven, for example crusty cobs, baps, soft rolls and bloomers, all of which are baked on baking sheets rather than in baking tins.

1. A bakery oven having means within the oven enclosure to atomise liquid water and means to feed liquid water to the atomising means for atomisation.

2. An oven as claimed in Claim 1, wherein the atomising means comprises a plurality of atomising devices spaced apart within the oven enclosure.

3. An oven as claimed in Claim 2, wherein each atomising device has means by which to feed the device with compressed air, means to cause the compressed air to vibrate at high frequency, and means to cause the vibrating air to act upon water fed to the device to atomise the water.

4. An oven as claimed in any preceding claim, wherein the oven is a travelling oven through which dough pieces can be conveyed, the atomising means being disposed adjacent the beginning of the conveyance path through the oven enclosure.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Bakery oven This invention relates to bakery ovens. In a known bakery installation, moulded dough pieces, after having been finally proved, are baked in tins in an oven for about 20 or 25 minutes. During the first 5 minutes that each dough piece is in the oven, it is subjected to a steamy atmosphere, caused by injection into the oven of steam which has been generated in a boiler. The purpose of the steam injection is three-fold: firstly, it causes the top of the loaf to glaze; secondly, it prevents or reduces breaking or splitting of the top of the loaf; and, thirdly, it reduces the springiness of the loaf and thus makes the loaf easier to cut and spreading of the slices easier. The use of steam injection does, however, have a disadvantage in that the energy required to heat the boiler to produce the steam adds to the running cost of the installation. In accordance with the present invention, there is provided a bakery oven having means within the oven enclosure to atomise liquid water and means to feed liquid water to the atomising means for atomisation. A specific embodiment of the present invention will now be described by way of example with reference to the accompanying drawing, which is a schematic sectional side view of an entrance portion of a bakery oven. Referring to the drawing, a travelling bakery oven has a heated entrance zone 10 into which proved dough pieces 1 2 are fed on a conveyor 14, each dough piece 1 2 being in a baking tin 1 6. A vertically slidable door 18 is provided at the entrance to the oven and a further such door 20 is provided downstream of the door 1 8. The doors are adjusted so that their lower edges are just clear of the dough pieces, and the lower edges may be provided with downwardly extending flexible lightweight flaps (not shown).The speed of the conveyor 14 is set so that each dough piece takes about 5 minutes to pass from door 1 8 to door 20, and the dough pieces then continue on the conveyor for baking in the main portion 22 of the oven for about 1 5 or 20 minutes. Two rows 24, 26 downwardly-directed atomiser nozzles 28 are mounted in the roof of the entrance zone 10 of the oven, each row 24, 26 extending transversely across the oven. Each nozzle 28 is fed with water, which is not previously heated, via a pipe 30 and with compressed air via a pipe 32 to produce a fog of atomised water to be discharged from the nozzle. The nozzles may be of the type sold under the trade name SONICORE by Ultrasonics Limited of Shipley, West Yorkshire. The compressed air fed to the nozzle is caused by a resonator chamber in the nozzle to form a standing shock wave. The water fed to the nozzle is caused by the shock wave to be shattered into droplets which are discharged from the nozzle. Although the discharged droplets will take heat from the oven in warming to the oven temperature, it is believed that there will be a substantial saving in energy compared with known ovens into which live steam is injected. A sketch costing for a typical bakery oven installation suggested that that oven would cost about 1 5000 less per year to run for a capital outlay of about 3000 or 4000 to convert the oven from using live steam injection to using water atomisers as described above. The invention may be applied to other types of bakery oven, for example rotary ovens in which the dough pieces are revolved on racks inside the oven enclosure. Also, the oven may be used for baking other bakery products which in the past have been subjected to a steamy atmosphere in the oven, for example crusty cobs, baps, soft rolls and bloomers, all of which are baked on baking sheets rather than in baking tins. CLAIMS

1. A bakery oven having means within the oven enclosure to atomise liquid water and means to feed liquid water to the atomising means for atomisation.

2. An oven as claimed in Claim 1, wherein the atomising means comprises a plurality of atomising devices spaced apart within the oven enclosure.

3. An oven as claimed in Claim 2, wherein each atomising device has means by which to feed the device with compressed air, means to cause the compressed air to vibrate at high frequency, and means to cause the vibrating air to act upon water fed to the device to atomise the water.

4. An oven as claimed in any preceding claim, wherein the oven is a travelling oven through which dough pieces can be conveyed, the atomising means being disposed adjacent the beginning of the conveyance path through the oven enclosure.