US2710993A

US2710993A - Insulated door structures

Info

Publication number: US2710993A
Application number: US297864A
Authority: US
Inventors: Floyd M Kirkpatrick
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1952-07-09
Filing date: 1952-07-09
Publication date: 1955-06-21
Anticipated expiration: 1972-06-21

Description

June 21, 1955 F. M. KIRKPATRICK 2,710,993

INSULATED DOOR STRUCTURES Filed July 9, 1952 Invehtor: Floyd M. Kirkpatrick,

by MW His Attcrneyb United States Patent 0 INSULATED DOOR STRUCTURES Floyd M. Kirkpatrick, Erie, Pa., assignor to General Electric Company, a corporation of New Y ork Application July 9, 1952, Serial No. 297 ,864

7 @laims. (Cl. 20-35) My invention relates to door structures and the like, and more particularly to insulated door structures.

In some door structures, for example, those used in refrigerators and the like, where a temperature differing substantially from that of the surrounding atmosphere is to be maintained within a storage compartment, insulation including an evacuated sealed envelope may be employed. This insulation may be, for example, in the form of an evacuated metal envelope including a glass fiber filler, such as that described and claimed in the copending application of Herbert M. Strong and Francis P. Bundy, Serial No. 236,788, filed July 14, 1951, and assigned to the same assignee as the present invention. Such insulation has excellent thermal insulating properties representing a substantial improvement in this respect over conventional or standard insulation, for example, atmospheric glass fiber batts used in many present-day refrigerators. Insulating structures of this type make possible a substantial reduction in the thickness of the door of a refrigerator so that thedoor shelves, for example, may be provided without any significant increase in the over-all thickness of the door beyond that now required for doors without shelves, or, conversely, without any loss in storage space in the compartment itself because of jutting door shelves. However, insulation of this type, because of the sealed envelope which is employed, introduces the problem of heat leakage from one wall of the envelope to the other along the edges thereof. By my invention a combined insulating structure is provided which minimizes the effect of such edge leakage and secures an overall improved door insulating structure.

It is an object of my invention to provide an improved insulating structure for doors and the like.

It is a further object of my invention to provide an improved arrangement for reducing edge losses of sealed evacuated insulating structures.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In carrying out the objects of my invention, the door is formed of an outer shell and spaced inner wall sealed to the outer shell to provide an evacuated space therebetween. Atmospheric insulation is disposed around the peripheral portion of the outer shell adjacent the edges of the inner wall and overlapping the edge portions of the inner wall. This atmospheric insulation, which is of a substantially greater thickness than the distance between the outer shell and the spaced inner wall, is enclosed by a breaker frame mounted with one edge thereof in abutting relationship with the inner wall of the envelope and extending to the outer shell.

For a better understanding of my invention, reference may be had to the accompanying drawing in which Fig. 1 is a front elevation view of a refrigerator cabinet incorporating an embodiment of my invention; Fig. 2 is a plan view, partly in section, of a portion of the refrigerator Patented June 21, 1955' illustrated in Fig. 1; and Fig. 3 is a view similar to Fig. 2 showing a modified form of my invention.

Referring to Figs. 1 and 2, there is shown a refrigerator 1 including a cabinet structure 2 and a door 3 mounted on the cabinet structure by hinges 4.

In order to maintain a satisfactory low temperature in the food storage compartment 5, both the cabinet 2 and the door 3 are thermally insulated. The door 3 is thermally insulated by providing throughout the major portion thereof insulation constructed in accordance with the invention of the aforementioned Strong and Bundy application. The door structure includes an outer shell 6 of pan-like configuration. This outer shell includes a face portion 7 forming the front face of the door, a peripheral section 8 extending rearwardly from the face portion 7 and generally perpendicular thereto, and an inwardly extending flange portion 9 extending inwardly from the inner or rear edge of the peripheral section 8.

The door structure further includes an inner wall 10 spaced from the outer shell 6. The edge 11 of the inner wall is sealed to the inner face of the outer shell 6 in any suitable manner, as by welding. The space between the outer shell 6 and the inner wall 10 is filled with a particular glass fiber insulation 12 in accordance with the teachings of the aforementioned Strong and Bundy application. The enclosed space between the outer shell and the inner wall is evacuated to a very low pressure, resulting in an insulation having greatly improved thermal properties. Because of these improved insulating properties, a much thinner wall of insulation may be employed than in the case of present conventional insulation, thereby greatly reducing the necessary thickness of the door for the same insulating value.

While an insulating structure such as that just described provides substantial thermal resistance to heat flow between the outer shell 6 and the inner Wall 10 throughout substantially the entire area of the door, this same resistance to heat flow does not exist at the edges of the inner wall 10, that is, in the region of the junction between the inner wall 10 and the outer shell 6 since, in this region, the outer shell and the inner wall provide for direct conduction of heat from one side to the other of the insulated space. This heat conduction is particularly significant where the outer shell 6 and the inner wall 10 are formed of a metal, such as low carbon steel, which is a relatively good conductor of heat. However, in any event, the heat conduction will be greater through the material of the outer shell and inner wall at the edge 11 of the inner wall 10, that is, at the junction between the shell and wall than through the evacuated structure forming the remaining area of the door. In addition, in the form shown in Fig. 2, the vacuum insulation does'not extend throughout the entire area of outer shell, introducing the problem of heat leakage beyond the limits of the vacuum insulated structure. The resultant heat leakage at the periphery of the door may result in warm areas in this region of the storage compartment and condensation or sweating on the exterior of the cabinet in this region. By my invention such heat leakage is minimized.

In accordance with my invention, atmospheric insulation 13, which may be, for example, glass fiber insulation, is disposed within the outer shell 6 adjacent the peripheral section 8 thereof. The atmospheric insulation 13, which is of substantially greater thickness than the distance between the face portion 7 of the outer shell and the inner wall 10, that is, the thickness of the evacuated portion of the door, is partially disposed between the inwardly extending flange portion 9 and the face portion 7 of the outer shell and extends inwardly beyond this region so as to overlap the edge portion 14 of the inner wall 10. By utilization of this thick mass of atmospheric insulation 13 overlapping the edge of the inner wall 10, heat transfer from the outer shell 6 of the door of the food storage compartment 5 is minimized, thereby minimizing any warm regions in the compartment 5 and also minimizing condensation of water or sweating on the exterior of the outer shell 6 of the doon In order to close the space between the inner wall 10 and the flange portion 9 of the outer shell 6 and to enclose the atmospheric insulation 13, a breaker frame or member is provided. The breaker frame 15 is formed of a material of low thermal conductivity, such as any of a number of plastic materials now employed for breaker strips. In order to hold the breaker frame 15 in position, one or more brackets or strips of L-shaped cross section, one of which is shown at 16, are employed. A bracket or strip 16 is preferably provided adjacent each of the four sides of the breaker frame 15. The member 16 may be in the form of a strip extending substantially the length of each edge portion 14 of the inner wall 10 or alternatively several spaced brackets may be employed along each side. As a further alternative, a single rectangular frame of L-shaped cross section may be employed in lieu of separate strips along the four sides. The brackets or strips 16 are secured to the inner wall 10 in any suitable manner, as by welding. The breaker frame 15 is mounted on the inner wall 10 by screws, one of which is shown at 17, received in the brackets 16 or by other suitable fastening means. By the arrangement described, one edge 18 of the breaker frame is positioned in abutting relationship with the inner wall 10. The other edge 19 of the breaker frame extends beneath a gasket 20 which is held in position by a retainer strip 21 secured in a suitable manner, as by screws (not shown), to the flange portion 9 of the outer shell 6. While the breaker frame 15 has been illustrated as of one-piece construction overlapping all four edge portions 14 of the inner wall 10, separate strips could, if desired, be provided along each of the four sides.

Further, the broad idea of a door structure including a vacuum panel and a peripheral portion of substantially thicker atmospheric insulation is not my invention but is described and claimed in the copending application of David W. Evans, Serial No. 297,959, filed July 9, 1952, and also assigned to the General Electric Company.

The particular arrangement for mounting the breaker frame 15 is not part of my invention but is described and claimed in the copending application of Robert A. King, Serial No. 297,938 filed July 9, 1952, and assigned to the General Electric Company, the assignee of the present invention.

It can be seen that the breaker frame 15 provides a path of low thermal conductivity between the inner wall 10' and the outer shell 6, encloses the atmospheric insulation 13, and provides a finished appearance to the door. It can be further seen that the provision of a substantially thicker portion of the door at the peripheral portion thereof results in the door having a deeply recessed portion 22 in the central area of the inner wall thereof. This provides a convenient space for mounting door shelves 23, shown in Fig. 1, without having the shelves project beyond the inner face of the door and thereby take up space in the food storage compartment 5. This combination of vacuum insulation and atmospheric insulation, by providing a very thin wall for the door in the central portion thereof, makes a large amount of space in the recessed area 22 available for the shelves.

A modified form of my invention is shown in Fig. 3. The same numerals have been employed to designate corresponding parts in Figs. 2 and 3. The outer shell 6 in the structure shown in Fig. 3 includes the face portion 7, the peripheral section 8 and the inwardly extending flange portion 9. In this modified form of my invention, an inner wall 24 having a pan-like configuration corresponding generally to that of the outer shell is employed. This inner wall 24 includes a central portion 25 spaced from the face portion 7 of the outer shell and a peripheral section 26 extending rearwardly and generally perpendicular to the portion 25. The peripheral section 26 is generally parallel to the peripheral section 3 of the outer shell and is spaced therefrom except at its edge 27. The outer shell and the inner wall are sealed at the edge 27 of the inner wall by welding or any other suitable manner. The space between the outer shell and the inner wall is filled with a particular glass fiber insulation 28 in accordance with the teachings of the aforementioned Strong and Bundy application. The enclosed space is evacuated to a very low pressure, resulting in insulation of greatly improved thermal properties.

The pan-like shape of the inner wall 24 provides for a deeply recessed portion 29 suitable for the reception of door shelves. Because of the pan-like shape of the inner wall, the sealing area between the outer shell 6 and the inner wall 24, that is, the area where these parts are welded together to seal the space between the outer shell and inner wall, occurs adjacent the junction between the peripheral section 8 and the inwardly extending flange portion 9. This is advantageous since, in the form shown in Fig. 2, it is possible in some cases for the welding, which occurs within the confines of the face portion 7 of the outer shell, to slightly mar the appearance of this face portion. The weld region in the form shown in Fig. 3 is disposed in an area where it is not noticeable. In order to further conceal any possible marring of the surface of the outer shell which may result from welding, a gasket 30 of a particular shape is provided. This gasket 31) is mounted on the flange portion 9 by the retainer strip 21 in the same manner as the gasket 20 of the form shown in Fig. 2. In order to conceal the weld area, the gasket 30 includes a portion or tail 31 extending from one edge of the gasket beyond the junction 32 between the peripheral section 8 and the flange portion 9. The gasket is formed, for example, by molding or extruding, so that this tail 31 fits closely adjacent the outer shell.

The form of invention shown in Fig. 3, like that shown in Fig. 2, includes the breaker frame 15 mounted on the inner wall 24 by the bracket or strip 16 and screws 17. One edge 18 abuts the inner Wall 24 and the other edge 19 is overlapped by an adjacent edge of the gasket 30. It further includes the atmospheric insulation 13, as in the form shown in Fig. 2.

While I have shown and described particular embodiments of my invention, I do not desire my invention to be limited to the particular constructions shown and described, and I intend by the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A door or the like comprising an outer shell of pan-like configuration, an inner wall spaced from said outer shell, said inner wall being sealed at its edges to the inner face of said outer shell, the space between said outer shell and said inner wall being evacuated, said outer shell extending beyond said inner wall, atmospheric insulation disposed within said pan-like outer shell at the periphery thereof, said atmospheric insulation overlapping the edge portions of said inner wall, said atmospheric insulation being of substantially greater thickness than the space between said outer shell and said inner wall, and a breaker member abutting said inner wall and enclosing said atmospheric insulation.

2. A door or the like comprising an outer shell of pan-like configuration, an inner wall spaced from said outer shell, said inner wall being sealed at its edges to the inner face of said outer shell, the space between said outer shell and said inner wall being evacuated, said outer shell extending beyond said inner wall, atmospheric insulation disposed within said pan-like outer shell at the periphery thereof, said atmospheric insulation overlapping the edge portions of said inner wall, said atmospheric insulation being of substantial- 1y greater thickness than the space between said outer shell and said inner wall, and a breaker frame abutting said inner wall and enclosing said atmospheric insula tion.

3. A door or the like comprising a metal outer shell of pan-like configuration, a metal inner Wall spaced from said outer shell, said inner wall being welded at its edges to the inner face of said outer shell, the space between said outer shell and said inner well being evacuated, said outer shell extending beyond said inner wall, atmospheric insulation disposed within said pan-like outer shell at the periphery thereof, said atmospheric insulation overlapping the edge portions of said inner wall, said atmospheric insulation being of substantially greater thickness than the space between said outer shell and said inner wall, and a breaker frame mounted on said inner Wall and enclosing said atmospheric insulation.

4. A door or the like comprising an outer shell of pan-like configuration, an inner wall spaced from said outer shell, said inner wall being sealed at its edges to the inner face of said outer shell, the space between said outer shell and said inner wall being evacuated, said outer shell extending beyond said inner wall, atmospheric insulation disposed within said pan-like outer shell at the periphery thereof, said atmospheric insulation overlapping the edge portions of said inner wall, said atmospheric insulation being of substantially greater thickness than the space between said outer shell and said inner wall, said outer shell including a flange portion extending inwardly from the periphery thereof. and a breaker frame mounted on said inner wall and extending to said flange portion and enclosing said atmospheric insulation.

5. A door or the like comprising an outer shell of pan-like configuration, said outer shell including a front face portion and a peripheral section extending generally perpendicular to said face portion, said outer shell further including a flange portion extending inwardly from said peripheral section and generally parallel to said face portion, an inner wall spaced from said outer shell, said inner wall being welded at its edges to the inner face of said outer shell, said inner Wall being of approximately the same area as said face portion of said outer shell whereby said weld occurs substantially at the periphery of said face portion of said outer shell, the space between said outer shell and said inner wall being evacuated, atmospheric insulation being disposed within said pan-like outer shell adjacent the peripheral section thereof, said atmospheric insulation overlapping the edge portions of said inner wall, said atmospheric insulation being of substantially greater thickness than the space between said outer shell and said inner wall, and a breaker frame abutting said inner wall and enclosing said atmospheric insulation.

6. A door or the like comprising an outer shell of pan-like configuration, said outer shell including a front face portion and a peripheral section extending generally perpendicular to said face portion, said outer shell further including a flange portion extending inwardly from said peripheral section and generally parallel to said front face portion, an inner wall of pan-like configuration spaced from said outer shell, said inner wall being welded at its edges to the inner face of said outer shell, said inner wall being of approximately the same area and shape as the combined front face portion and peripheral section of said outer shell whereby said weld occurs substantially at the junction of said peripheral section and said flange portion of said outer shell, the space between said outer shell and said inner wall being evacuated, atmospheric insulation being disposed within said pan-like outer shell adjacent the peripheral section thereof, said atmospheric insulation overlapping the edge portions of said inner wall, said atmospheric insulation being of substantially greater thickness than the space between said outer shell and said inner wall, and a breaker frame abutting said inner wall and enclosing said atmospheric insulation.

7. A door or the like comprising an outer shell of pan-like configuration, said outer shell including a front face portion and a peripheral section extending generally perpendicular to said face portion, said outer shell further including a flange portion extending inwardly from said peripheral section and generally parallel to said face portion, an inner wall of pan-like configuration spaced from said outer shell, said inner wall being Welded at its edges to the inner face of said outer shell, said inner wall being of approximately the same area and shape as the combined front face portion and peripheral section of said outer shell whereby said weld occurs substantially at the junction of said peripheral section and said flange portion of said outer shell, the space between said outer shell and said inner wall being evacuated, atmospheric insulation being disposed within said pan-like outer shell adjacent the peripheral section thereof, said atmospheric insulation overlapping the edge portions of said inner Wall, said atmospheric insulation being of substantially greater thickness than the space between said outer shell and said inner Wall, a breaker frame abutting said inner wall and enclosing said atmospheric insulation, and a gasket mounted on said flange portion, said gasket including one edge overlapping one edge of said breaker frame, the other edge of said gasket extending beyond said junction of said peripheral section and said flange portion of said outer shell to cover the weld area.

References Cited in the file of this patent UNITED STATES PATENTS 2,046,909 Terry et al. July 7, 1936 2,047,996 Crosley, Jr. et al July 21, 1936 2,061,453 Crosley, Jr. et a1. Nov. 17, 1936 FOREIGN PATENTS 517,149 Great Britain Jan. 22, 1940