Cooking Oven with Anti-Condensation Door

Abstract

The present invention refers to a cooking oven, which is provided with a cooking cavity and a door adapted to close it, wherein such door is provided with an outer frame and one or more glass panes supported by such frame along the periphery thereof, wherein on the surface of at least one of said glass panes there are applied heating means, which comprise a layer of substantially clear, i.e. transparent resistive material, means adapted to connect two sides of such layer of resistive material to appropriate terminals energizable by an electric voltage supplied from a source available inside said oven.

Description

Advantages and features of the present invention will anyway be more readily understood from the description that is given below by way of non-limiting example. with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a cooking oven according to the present invention, in the state in which its door is opened and viewed from the inside thereof;

FIG. 2 is a perspective view of the oven shown in FIG. 1, wherein its door is in its open state, but the two glass panes thereof are partially spaced apart;

FIG. 3 is an enlarged view of a detail of FIG. 1;

FIG. 4 is a plan symbolical view of a glass pane of the oven door according to the present invention, as viewed with some partial enlargements thereof;

FIG. 5 is a simplified cross-sectional view of the door of the oven according to the present invention, as viewed across the section plane A-A of FIG. 1.

With reference to the above-noted Figures, an oven according to the prior art comprises:

• • a cooking cavity 1,
  • a door 2 adapted to close the cooking cavity and comprised of an outer frame 3 that retains, with its inner perimeter portion, two glass panes, i.e. an inner and an outer pane 4 and 5, respectively, provided in a mutually opposing arrangement parallel to each other, so that between said peripherally retaining frame 3 and said two glass panes there is defined a thermally insulating hollow space or gap 7.

According to the present invention, on the surface 6 of the inner glass pane 4 facing into said hollow space 7 there is applied a layer of resistive material 8. Such layer of resistive material may be formed of any material or compound that combines good processability with an appropriate capability of being applied in the form of a layer, jointly of course to an appropriate resistance to high temperatures and a marked long-term stability.

Furthermore, the above-mentioned resistive material shall be capable of being applied to form very thin layers, e.g. layer having a thickness in the order of just a few microns, so that the glass pane on which it is applied remains substantially clear and transparent or—at most—undergoes just a very slight variation in its transparency.

This layer of resistive material shall be connected to a power supply source, so that during the operation of the oven, i.e. when the high temperature reached in the cooking cavity of the oven causes a condensate film to deposit and form on the inner surface 9 of the outer glass pane 5, such power supply from said source to said layer 8 causes the latter to heat up to a sensible extent, so that also the air contained in the hollow space 7 is heated up to in turn cause said condensate film to evaporate.

Said layer of resistive material shall not necessarily be applied to cover the entire surface 6 of the inner glass pane 4, but may rather be applied on just a defined portion thereof, namely onto and along a vertically extending strip, as this is best illustrated in FIGS. 4 and 5.

This is in fact effective in ensuring that the sole middle portion of the surface of the glass panes is kept free of condensate forming thereon, so as to facilitate viewing into the cooking cavity and watching the food being cooked there. This furthermore adds to the fact that, since in cooking ovens intended for commercial foodservice and mass-catering applications food is cooked in pans that are usually arranged one above each other on a number of tiers, ensuring good visibility into the cooking cavity all along a strip extending vertically enable the state of the food to be advantageously monitored in all such pans placed above each other over the entire height of the cooking cavity.

For such layer of resistive material 8 to be connected electrically to said power supply source, at the two opposite vertical edges of said layer of resistive material 8 there are advantageously provided two respective conductive members 12, 13 that substantially work as typical bus bars, which may be provided in the form of normal electric conductors and are of course in contact with the conductive material of the portion of layer 8 situated along said opposite edges thereof.

These conductive members 12, 13 are adapted to be connected to appropriate electric terminals (not shown) of the electric circuit of the oven with the aid of connecting means as generally known as such in the art, such as for instance simple electric conductors 31, 32. For reliability and safety reasons, however, it turns out as being particularly advantageous if the connection between said conductive members 12, 13 and the electric circuit included in the structure of the oven is comprised of automatic-release fit-in moving contacts, as they are generally known as such in the art, namely a first pair of automatic-release fit-in moving contacts 14A and 14B, which are provided on the inner edge of the frame 3 and the corresponding site on the outer portion 23 of the oven against which said frame 3 abuts when closing, respectively, for a first connection, and a second pair of automatic-release fit-in moving contacts 15A and 15B for a second, similarly made connection.

The advantage of automatic-release fit-in moving contacts derives also from the fact that, when the oven door is opened, they separate from each other, thereby opening, i.e. disconnecting the electric power-supply circuit and completely and safely isolating said layer 8 therefrom, so as to do away with any risk of said layer 8 and the related electric connections arranged on the door being kept energized, i.e. in a live condition when the door is open and, therefore, said connections and parts become exposed and accessible.

With reference to FIGS. 1, 2 and 3, the inner glass pane 4 is designed to be partially removable from the working position thereof, in that it is namely hinged along the vertical outer edge 21 thereof—which extends contiguously to the vertical edge 22 of the frame 3 that is hinged on to the structure of the oven—by means of hinges 20 of a kind largely known as such in the art.

When the oven door is open, this solution enables said inner glass pane 4 to be opened and said hollow space 7 to be exposed for convenient accessibility in view of cleaning the glass surfaces, as this is regularly required, and/or performing regular maintenance.

As far as the above-mentioned layer of resistive material 8 is concerned, it may be advantageously comprised of stannous oxide; furthermore, it may be found on the market under the trade name of “C-50-Schott”. It has been found that—at least as far as cooking ovens of the kind intended for commercial foodservice and mass-catering applications are concerned—the power input to said layer should be rated to result in a power density situated anywhere between 1500 and 2200 Ohm/m² and the resistance measured across said conductive members 12, 13 of said vertical strip of resistive layer 8 should be situated anywhere between 15 and 25 Ohm/m² for the condensate to be able to evaporate, while preventing the glass pane from heating up to any excessive extent.

In addition, for safety reasons—as generally required by safety standard regulations—the supply voltage used to energize said resistive layer 8 is most appropriately limited to max. 48 V.

For aesthetic reasons, i.e. for reasons of uniformity in both transparency and hue of the glass on which said resistive layer 8 has been applied, it may prove useful if even the remaining portion 6A of the surface 6 of the inner glass pane 4 is treated with the application of a similar layer of resistive material (see FIG. 4) that has however not to be electrically connected to any power source, so that it does by no means take part in the condensate removal process.

Claims

1. Cooking oven, preferably of the kind intended for use in commercial foodservice and mass-catering applications, comprising: a cooking cavity (1),a door (2) adapted to close said cooking cavity and provided with an outer frame (3),and one or more glass panes (4, 5) supported by said frame along the periphery thereof,wherein on the surface of at least one of said glass panes there are applied heating means,

2. Cooking oven according to claim 1, characterized in that said layer of resistive material is applied along a vertical strip extending centrally on the glass pane on which it is applied.

3. Cooking oven according to claim 1 or 2, characterized in that said layer of resistive material has a surface resistance comprised between 15 and 25 Ohm/m2.

4. Cooking oven according to claim 1 or 2, characterized in that at two opposite, preferably vertical edges of said vertical strip there are provided two respective conductive members or bus bars (12, 13), each one of which is electrically connected to a respective one of said edges.

5. Cooking oven according to claim 1, characterized in that between the structure of said oven and said door there are provided electrically connecting means, and in that each one of said conductive members, or bus bars, is electrically connected to a respective one of said electrically connecting means.

6. Cooking oven according to claim 5, characterized in that said electrically connecting means comprise two pairs of automatic-release fit-in moving connectors (14A, 14B; 15A, 15 (14A, 14B, 15A, 15B) adapted to separate automatically whenever said oven door is opened.

7. Cooking oven according to claim 1, characterized in that said door is provided with two mutually opposing glass panes (4, 5) extending parallel to each other at a definite distance from each other, so that a hollow space (7) is defined therebetween, and in that said layer of resistive material (8) is applied on the surface (6) of the inner glass pane (4) that faces into said hollow space.

8. Cooking oven according to claim 7, characterized in that said inner glass pane (4) is adapted to be selectively hinged on to said outer frame (3) of the door, preferably with the aid of hinging means (20), between a vertical corner (21) of said pane and a vertical edge (22) of said frame, so as to be able to open out relative to said vertical edge (22) of said frame.

9. Cooking oven according to claim 1, characterized in that said layer of resistive material is prevailingly comprised of stannous oxide.

10. Cooking oven according to claim 1, characterized in that said oven is provided with power supply means adapted to energize said layer of resistive material (8) at a low voltage not exceeding 48 V.

11. Cooking oven according to claim 1, characterized in that it is adapted to supply said layer of resistive material with a power comprised between 1500 and 2200 W/m2.

12. Cooking oven according to claim 1, characterized in that the remaining portion (6A) of the surface (6) of the inner glass pane (4), which is not covered by said electrically connected, i.e. energizable layer of resistive material (8), is coated with a respective distinct layer of material having the same properties, which is however not electrically connected to any power source.