Door cooling system

Abstract

A baking and broiling oven having air cooling channels surrounding an insulated oven liner. A cooling fan is located in the air channels to induce an air flow around the oven liner. The oven liner includes a front access door with a vertical cooling air channel extending therethrough. A converging exhaust nozzle discharges the air from the fan forwardly of the oven. This nozzle is located over the top edge of the door to reduce the static pressure at the top edge of the door and to serve as an aspirator for the cooling air movement passing up through the channel in the door.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to baking and broiling ovens, and particularly to a forced air cooling system for maintaining the outer surfaces of the oven below a predetermined maximum temperature. This invention is primarily directed to means for increasing the flow of cooling air up through the front door of the oven.

2. Description of the Prior Art

Air cooling systems have been built into oven designs for many years as is shown by U.S. Pat. No. 3,121,158 of Bohdan Hurko, which is assigned to the same assignee as the present invention. Such cooling systems are particularly useful with ovens that are provided with a pyrolytic self-cleaning oven cycle where the temperatures within the oven cooking cavity may reach as high as 950.degree.F. High temperature limits are even more difficult to maintain when a self-cleaning oven is built into a wall, rather than being a free-standing appliance. An air cooling system for a built-in wall oven is described in U.S. Pat. No. 3,310,046 of George A. Scott and James K. Newell, Jr., which is also assigned to the assignee of the present invention. Cooling air channels have also been provided in the oven doors for permitting natural convection air currents to flow up through the door and thereby reduce the exterior temperatures of the door. One such door design is shown in U.S. Pat. No. 3,736,916 of James A. White, which is also assigned to the present assignee.

The principle object of the present invention is to provide a forced air cooling system for a baking and broiling oven with a converging exhaust nozzle located above the top edge of the door to reduce the static pressure in this area and serve as an aspirator in conjunction with vertical air channels formed in the door.

A further object of the present invention is to provide a forced air cooling system for a baking and broiling oven with a high velocity air curtain sweeping over the top edge of the door so as to draw convection air currents up through the door and reduce the external surface temperatures of the door.

SUMMARY OF THE INVENTION

The present invention, in accordance with one form thereof, relates to an oven construction having a heated cooking cavity formed by insulated walls. There is an outer oven cabinet surrounding the insulated oven walls, and cooling air channels formed within the oven cabinet so that air flowing through the channels will reduce the outer surface temperatures of the cabinet. The oven door has a vertical air cooling channel. There is a cooling fan located in the oven cabinet for producing a strong draft of air in the oven cabinet. A converging exhaust nozzle is formed in the top air channel of the cabinet to overlie the top edge of the door and produce a high velocity air curtain over the air outlet openings in the top edge of the door, and thus reduce the static pressure at this location so as to aspirate air up through the door for an increased reduction in outer surface temperatures of the door.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will be better understood from the following description taken in conjunction with the accompanying drawing, and its scope will be pointed out in the appended claims.

The drawing is a right side elevational view of an electric built-in wall oven with some parts broken away and others in cross-section to show the general nature of the oven construction, as well as the forced air cooling flow pattern around the oven liner and the aspirator means for drawing an increased amount of cooling air up through the oven door.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to a consideration of the drawing, there is shown a built-in wall oven 10 having an oven cooking cavity 12 formed by a box-like oven liner 14 with a front opening that is adapted to be closed by a hinged drop door 16. The particular oven shown is an electric oven, as is clear from the presence of an upper broil element 18 adjacent the top wall of the oven liner 14. However, this invention is not limited to use with electrically heated ovens; it could just as well be used with a gas heated oven, both of which are conventional in this art. A layer of thermal insulating material 20 such as fiber glass or the like is placed around the outside of the oven liner 14 for retaining as much as possible of the oven heat within the cooking cavity 12. An oven cabinet construction 22 encircles the insulated oven liner 14, but it is spaced outwardly therefrom to form cooling air channels 24 at least up the two sides of the oven, and up the back of the oven, and across the top of the oven. At the bottom of the oven there may be a slightly different construction. It may be left somewhat open at the bottom, except for a pair of spaced runners 26 on which the oven would be supported during assembly in the factory or display in the applicance dealer's showroom. In any event, cooling air is allowed to flow beneath the bottom of the insulated oven liner. The outer oven cabinet 22 has opposite side walls 28 which do not extend down to cover the runners 26, but they are shortened so that air may flow underneath the lower edge of the side walls 28 and rise up through the air channel 24 formed between the side wall 28 and the layer of insulation 20 that surrounds all of the walls of the oven liner 14. At the front of the oven, beneath the oven door 16, is an open grill work 30 of elongated shape that extends from side to side of the oven cabinet and serves as a primary air inlet means for the air cooling channels 24 within the oven cabinet 22. Additional air inlet openings may be formed in the front frame of the outer oven cabinet 22 that surrounds the front door opening along the two sides of the door, but these are not shown and they do not form a necessary part of the present invention.

The air channel 24 above the oven liner is provided with a transverse partition which extends from one side of the oven cabinet 22 to the other to substantially subdivide this top air channel into a back portion 36 and a front portion or plenum chamber 38. This partition 34 has a circular opening 40 in which is mounted a small fan 42 that is supported on a shaft 44 of a small motor 46 that is supported from the partition. Accordingly, when the motor 46 is energized, the rotation of the fan blades 42 will draw room air through the air inlet opening 30 at the front bottom of the oven cabinet 22 to pass across the underside of the oven liner and up the three vertical air channels around the oven and then into the rear channel 36 at the top of the oven. Then all of the cooling air will pass through the fan opening 40, and this cooling air will be allowed to pass across oven control components 50 which are mounted behind a control panel 52 that is located generally above the oven door 16. A representative control component 50 is shown with a manual control knob 54. This forced air oven cooling system is generally taught in the beforementioned Scott and Newell U.S. Pat. No. 3,310,046.

Attention will now be directed to the construction of the oven door 16. This door is generally of sheet metal construction having three main elements; an outer door panel 60, an inner door liner 62, and a small central inner panel 64 that is supported from the inner door liner. The outer door panel 60 is of shallow pan configuration by virtue of the fact that it has a slight rearwardly facing peripheral flange 66. The inner door liner 62 is also of shallow pan configuration, and it is of mating or telescopic construction with the outer door panel 60 by virtue of the fact that it has a slight front facing peripheral flange 68 which slips into the peripheral flange 66. Suitable screw fasteners (not shown) hold the inner door liner 62 to the outer door panel 60 near the top edge of the door in conjunction with the oven door handle 70 that is located along the front face of the door near the top thereof. At the bottom of the door, there is a tab and slot connecting relationship at 72 along most of the bottom edge of the door which prevents separation of the outer door panel 60 from the inner door liner 62 unless the above-mentioned screw fasteners at the top of the door are first removed.

The inner door liner 62 includes a generally rectangular outward embossment 74 which is adapted to project somewhat into a recessed front frame 76 of the outer oven cabinet 22, that surrounds the oven liner 14. The box-like oven liner 14 has an outwardly turned front flange 78 which bears against the front frame 76 due to the oven liner being pulled rearwardly into the oven cabinet by tension means (not shown) such as J-bolts or the like, as is standard practice in this art. The central inner panel 64 is also of shallow pan shape with a slight front facing peripheral flange 80, and this inner panel is adapted to project into the throat of the oven liner 14 in the manner of a close-fitting plug. The flat face of the embossment 74 of the inner door liner 62 is formed with a large opening or cut-out for accommodating the flanged portion 80 of the inner panel 64 therein, so that the inner panel substantially fills the opening. This opening is also provided with an inwardly turned, front facing peripheral flange 82 which closely parallels the peripheral flange 80 of the inner panel. Wrapped around the peripheral flange 80 near the edge thereof is a strip gasket 84 of thermal insulating material such as woven fiber glass or the like. This gasket 84 has an enlarged exposed edge 86 that is adapted to seal against the front flange 78 of the oven liner when the door 16 is closed. This strip gasket 84 is sandwiched between the flange 80 and the generally parallel flange 82 to serve as a thermal break between the inner panel 64 and the inner door liner 62. Fastening screws 88 are threaded from inside the inner panel 64 and extend through the flange 80, the gasket 84 and the flange 82.

This particular oven door 16 happens to be provided with an oven window 90, although the present invention does not require a window in the door. The outer door panel 60 has a window opening 92 with a rearwardly turned collar 94. Over this window opening is sealed a first panel 96 of high temperature glass or the like. The inner panel 64 is also provided with a window opening 98 having a front facing flange 100 over which is sealed a double window pack 102 comprising a pair of glass panes 104 and 106 which are held apart by a peripheral spacer frame 108, and assembled together by a channel member 110 which extends completely around the window pack and is fastened together at its two ends to form a complete sub-assembly. Surrounding the window pack 102 is a layer of thermal insulating material 112 such as fiber glass or the like. This insulation working in conjunction with the double window pack 102 serves as suitable thermal insulating means to retain the heat within the over cooking cavity 12. The insulation 112 is confined by an insulation guard 114 which is a sheet metal plate that is fastened to the flange 82 by a screw fasteners 116. Of course, the insulation guard 114 has a suitable window opening in the vicinity of the double window pack 102 so as not to obscure the view through the window.

A vertical air channel 120 is present within the oven door 16, and it is located generally between the outer door panel 60 and the inner door liner 62 and the insulation guard 114. Air inlet openings 122 are formed along the bottom edge of the door in the flange 66, and air outlet openings 124 are formed along the top edge of the door in the flange 66. Secondary air inlet openings 126 are formed in the top portion of the collar 94 that surrounds the first window opening 92 in the outer door panel 60. The area above the window opening 92 is covered by a plate 128, such that there is a secondary air channel 130 adjacent the top of the door. This channel 130 also has air outlet openings 132 along the top edge of the door.

The plenum chamber 38 behind the control panel 52 has an exhaust means in the form of a converging nozzle 135 which is located along the bottom edge of the control panel 52 and extends substantially from one side of the oven to the other so as to generally overlie the top edge of the oven door 16. The throat 137 of this nozzle is located substantially directly over the air outlet openings 124. The discharge angle of this nozzle 135 is generally in a horizontal plane to form a high velocity air curtain over the air outlet openings 124 and 132. This high velocity causes a reduction in the static pressure in this area, thereby serving as an aspirator or draw air up through the air channels 120 and 130 within the door 16. It will be understood that the greater the air flow through these air channels the lower will be the resulting exterior surface temperatures of the door. Accordingly, I have taken advantage of the usual air cooling fan 42 which serves to cool around the insulated oven liner, and I have used this cooling air movement in a novel way to effect a greater flow of air through the oven door.

Modifications of this invention will occur to those skilled in this art, therefore it is to be understood that this invention is not limited to the particular embodiment disclosed, but that it is intended to cover all modifications which are within the true spirit and scope of this invention as claimed.

Claims

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An oven having a cooking cavity formed by a box-like oven liner and a front-opening access door, heating means for applying heat energy to the cooking cavity, thermal insulating means surrounding the oven liner and also included within the said door for retaining the oven heat within the cooking cavity, an outer oven cabinet surrounding the insulated oven liner, cooling air channels formed within the oven cabinet around the oven liner as well as within the door for reducing the outer surface temperatures of the cabinet and door as room ambient air flows through the air channels, the door having air inlet openings along its bottom edge and air outlet openings along its top edge to create a vertical flow of natural convection air currents, the outer oven cabint having air inlet means for introducing air into the cooling air channels of the cabinet, blower means located in the oven cabinet for producing a forced draft of air in the air channels within the oven cabinet; the invention comprising a converging exhaust nozzle communicating with the top air channel of the oven cabinet to overlie the top edge of the door and sweep a high velocity curtain of exhaust air over the air outlet openings in the door and thus reduce the static pressure at the air outlet openings of the door so as to asprirate air up through the door for an increased reduction in outer surface temperatures of the door.

2. An oven as recited in claim 1 wherein the throat of the converging nozzle is substantially located directly over the air outlet openings in the top edge of the door, and the exhaust air is directed in a generally frontward direction away from the oven.

3. An oven as recited in claim 2 wherein the said air outlet openings in the upper edge of the door comprise a series of slots which substantially extend from one side of the door to the other, and where the said converging exhaust nozzle overlies substantially the entire width of the door.