US2768046A - Insulating structures - Google Patents

Description

Oct. 23, 1956 w EVANS 2,768,046

INSULATING STRUCTURES Filed July 9, 1952 David W- Evafis,

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His Att fney.

United States Patent INSULATING ST RUCT URES.

David W.,;Evans, Erie, Pa., assiguor to General Electric Company, acorporation of New York Application July 9, 1952, Serial No. 297,959

6 Claims. (Cl. 312-214) My invention relates to refrigerator cabinets :and the like, and more particularly to insulating structures therefor.

In some cabinets, such as refrigerator cabinets and the like, where a temperature differing substantially from that of the surrounding atmosphere is to be maintained, 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 Jul-y 14, 1951,,a-ndassigned to the same assignee as the present invention. It is tobe understood that my invention is an improvement over the invention of the. Strong and Bundy application, and therefore, I do not claim as my invention anything shown or described in said Strong and Bundy application,

which is to be regarded as. prior art with respect to the present application. Insulation such as that described and claimed in the Strong and. Bundy application has excellent thermal insulating properties,representinga substantial improvement in this. respect. over conventional or standard.- insulation, for example, atmospheric glass. fiber batts, i. e,.,, glassfiber batts under atmospheric conditions, used. in many presentaday. refrigerators Such yacuum panels may conveniently be. employed between the. inner and, outer walls. of conventional refrigerators in. lieu of the H standard insulation. Whenfso. employed, they makefposv sible, a, substantial reduction in the, thickness of the walls,

thereby materially increasing the available interior storage space, for the same exterior dimensions. Howeveninsnlation, of this type, because. of the. sealed'envelopewhich is employed has introduced the problem ofi heat. leakage from one wall of the. panel to the other along the: edges thereof, Bymy invention, arcombinedinsulating structure isprovided which minimizes the effect. of such edge leakage and secures. an overall improved cabinet insulatingstructure,

It: is an object oh my invention to. provide. animproved insulating structure for cabinets and the. like.

his another object of my invention to provlid'e an improved, insulating, structure for doors utilized as parts of such cabinets.

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

Further. objects and advantages of my invention will become. apparent. as the following description proceeds, and the features of novelty which characterizes my inventhan will be pointed out with. particularity in'the-cla'ims annexed to and. formingpart of this. specification.

In carrying out the objects of my invention, vacuum panels including sealed envelopes are employed in the two, side walls and the top wall. ojf the cabinet, and in the door. The top corners of the'c'abinet' are' fothiedto provide a space for receiving atmospheric insulation to provide a long thermal path' and to reduceheat losses.

at-theedgesoftthe panels. Atmosphericinsulationis used 2,768,046 Patented Oct. 23, 1956 =inthe back Wall and in the bottom wall of the cabinet.

The door is shaped to provide a portion of increased thickness'a'long theperimeter'thereof, and atmospheric insulacabinet'incorporating an embodiment of my invention; Fig. '2. is 'an 'enlargedsectional plan view taken along the line 22 in Fig. '1 and looking in the direction of the arrows; Fig. 3 is a sectional plan view of aportion of a door showing a modified formof my invention; and 'F i g. 4 isa view-similar to Fig. 3 showing another modified form of my invention.

Referring 'to Figs. 1 and 2, there is shown a refrigerator cabinet -1 including an outer wall or shell 2 and an inner wall or liner 3 spaced from the outer wall and defining a flood storage compartment 4. A machinery compartmentS is provided below the food storage compartment. The access opening of the. food storage compartment is closed by a door 6- and the access opening of the machinerycompartment 5 is closed by a cover 7. The space between the outer andi'nn'er walls 2 and 3, respectively, at the access opening is closed by a breaker strip 7a of a material of low thermal conductivity, such as any of several plastic materials now generally employed; The breaker strip maybe held in position by screws, one of which is shown at 7b, engaginga nut strip 70 on the inner liner3. The particular mounting of the breaker strip with one end. overlapping an inturned flange of the outer wall and with. a screw engaging the inner wall is not part of my invention but, in connection with the mounting of a gasket, is described and claimed in the cop'ending application of Leroy R. Patterson, Jr.,.Serial No. 321,368 filed November 19-, 1952, now Patent No; 2,704,698; granted March- 22, 195 5, and assigned to the same assignee as the present application;

The foodv storage compartment 4 is cooled by refrigerating apparatus (not shown) so that a substantial difference in temperature normally exists'between the temperature within the compartment 4 and the temperature of the-atmosphere surrounding the cabinetil; To'assist in maintaining this temperature ditferential, the space While inthe.structure illustrated in Fig. 1 only the vacuum panel 8 in the left-hand side wall has been shown, it will be understood that the same construction is employed in the. right-hand side wall which is'not shown in section. Each-panelmay be placed between the outer and inner walls 2 and 3 in any suitable manner. By way of example, in the form illustrated, a plurality of spaced strips or spacer members 10,- which may, be simply strips of cardboard, are employed between-the walls of the panel and the inner and outer walls of the cabinet, so as to permit somerelative movement of the panel-and the walls. It will be apparent, however, that these spacer strips could be omitted. if desired.

Each of the panels 8 and9 may be made in accordance with the invention disclosed'in the aforementioned Strong net.

The space between the members 11 and 12 is filled with a particular glass fiber insulation 13 in accordance with the teaching of the aforementioned Strong and Bundy application, and the adjacent edges 14 of the members 11 and 12 are welded to seal the envelope. The enclosed space is evacuated to very low pressure, resulting in an insulation having greatly improved thermal insulating 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 thickness of the cabinet walls and substantially increasing the available food storage space within the cabinet.

While such panels provide substantial thermal resistance to heat fiow between the sheets 11 and 12 throughout almost the entire area of the panel, this substantial resistance does not exist at the edges of the panels because in these regions the envelope members 11 and 12 provide for conduction of heat directly from one Wall of the panel to the other. This heat conduction is particularly significant where the sheets 11 and 12 are formed of a metal such as steel which is a good conductor of heat. However, in any event, the heat conduction will be greater through the material of the sheets 11 and 12 at the edges, for example, through the path at A, than through the evacuated structure forming the remaining area of the panel, for example, through the path B. This introduces the problem of heat leakage at the perimeter of each of the panels, with resulting warm areas in these regions of the storage compartment and condensation or sweating on the exterior of the cabinet in these regions. By my invention the adverse efiects of such edge losses in vacuum panels are materially reduced.

Referring to Fig. 1, the uper corners of the liner 3 are inclined or chamfered, as indicated at 15, providing an increased distance between the edges of the panels and the inner liner in these regions. While only a portion has been shown in Fig. 1, it will be understod that the inclined section 15 could, if desired, extend around the entire perimeter of the top wall of the liner. The space between the inclined section 15 and the adjacent edges of the panels 8 and 9 is filled with atmospheric insulation, for example, glass fiber insulation. This insulation, indicated at 16, fills the space between the section 15 and the edges of the panel and also surrounds and encloses the edges of the panels, as indicated at 17, for example.

It can be seen by reference to Fig. 1 that with this construction a substantially longer heat flow path is provided at the inclined section 15 and the thickness of atomspheric insulation thus made available is sufiicient to give substantially the same resistance to heat flow between the outer and inner walls 2 and 3 in this region as is provided by the smaller thickness of insulation afforded by the vacuum panel in the remainder of the top and side walls of the cabinet.

While vacuum panels could, if desired, also be employed in the rear wall of the refrigerator cabinet, I prefer to employ a batt 18 of atmospheric insulation, such as the glass fiber insulation employed at 16, in the space between the rear wall 19 of the outer wall 2 and the rear Wall 20 of the inner liner 3. As a practical matter, the exterior depth of the refrigerator cabinet is determined by the standard depth of other kitchen appliances and cabinets. The interior depth is also somewhat limited because if this depth becomes too great, the difficulty of access to items stored in the rear of the food storage compartment 4 becomes significant. Also, in many refrigerators it is customary to install the evaporator through an opening in the rear wall, and making the insulation of the rear wall of a sealed vacuum panel would introduce some Clifi'lCLllliCS in connection with the assembly of the evaporator. Accordingly, in the refrigerator cabinet herein disclosed, atmospheric rather than vacuum panel insulation is employed in the rear wall of the cabi- The use of this standard insulation and hence the much greater thickness thereof employed increases the distance between the edge 14 of the panel as shown in Fig. 2 and the closest point 21 of the liner over that which would exist were the thinner vacuum panel also to be employed in the rear wall. The arrangement illustrated in Fig. 2 thus provides for an increased length of heat path from the edge of the panel and hence minimizes the adverse etfect of edge losses through the metal envelope of the panel, as discussed above. It will be apaprent that alternatively, if a vacuum panel were employed in the rear wall of the cabinet, the corners of the liner at the junctions between the rear and side walls thereof could be chamfered in the same manner as corner 15 previously described, and the corner of the liner at the junction of the rear and top wall of the liner could, as mentioned above, be chamered in the same manner as the corner 15.

Vacuum panel insulation also could be employed, if desired, in the bottom wall of the cabinet, i. e., in the wall between the food storage compartment and the machinery compartment 5. In accordance with the form illustrated, however, a batt 22 of atomspheric insulation similar to the batt 16 described above, is also employed in this bottom wall. This batt, like the batt 18, being of substantially greater thickness than the vacuum panel, provides an increased length of heat flow path from the edge 14 and hence from the outer metal wall 12 of the panel to the adjacent corner 23 of the liner.

A vacuum panel 24 is also provided to insulate the door 6. The door includes an outer metal wall 25 and an inner metal wall 26 connected by a breaker strip 27 of suitable thermal insulating material, such as one of the plastic materials currently employed for this purpose. The breaker strip may be secured to the inner wall 26 by screws, one of which is shown at 28. The vacuum panel 24 is spaced from the outer and inner walls 25 and 26 by spacers 29, which may be cardboard strips. The panel 24 is made in the same manner as the panel 8 described above and includes two sheets or members 30 and 31, sealed at their abutting edges 32. As in the case of the panel 8 one sheet 30 may be pan-shaped and the other sheet 31 may be flat. The space between the members 30, 31 is filled with the particular glass fiber insulation 33 disclosed in the aforementioned Strong and Bundy application. The use of this improved insulation provided by the vacuum panel makes possible a substantial reduction in the thickness of the door. However, the edge loss problem discussed in connection with the cabinet structure above is also present in the door structure employing the vacuum panel, i. e., the heat loss in the region 34 between the outer member or sheet and the inner member or sheet of the panel. In accordance with my invention, the effect of this heat loss is minimized by substantially increasing the thickness of the door in the region of the perimeter thereof. Thus, the door in the region 35 is made of substantially greater thickness than the remainder of the door area. The inner wall 26 of the door is drawn into a pan-shape, as indicated at 36, to provide for this greater thickness adjacent the perimeter. This shape of the inner wall of the door is advantageous in that it provides a space for mounting door shelves without having the shelves project material beyond the inner face of the door. The space 35 is filled with atmospheric insulation, for example glass fiber insulation such as that employed at 16, this atmospheric insulation also surrounding the edge of the vacuum panel 24 in the region 34 and providing a substantially increased heat flow path over that which would be available were the thickness of the door not increased at the perimeter thereof. Because of the substantially increased thickness, the insulating value of the atmospheric insulation employed can be made substantially the same as that of the much thinner vacuum panel is employed for insulation throughout the remainder of the door, and this thicker insulation in the particular region door shelves and to provide a th t' s ti-min miza h s edge, 's s be w n. th metal -sheets oil-walls ,ot th'e panel. l lle nceit'he'po s ofajwarm area wilhin the remnant co'" region andt he possibility of V I on thetexterior of'ihe doqr in' this region is or sweating minimized.

In Fig. 3-, therevis shown a modified form of door structure which incorporates the same general insula ug struc- Plas i i t i I nn Wa 7 di t wtlm, mite Zi'piarid. breakenstri ,1 L

neral shape'as the com- 'wall'37 is molded t the same ge bined metal innerwallwand breaker strip.27=, 28 of Fig. 2 providing .a recesseipp rtiqn fl su itable for the reqeptiqn of door shelves and the'thicker portion .35 at the perimeter of the door. The regio I atmospheric; insulating material, s as the; 'insplati ng ,material employed in Big. i

Another form of door structure i orporta tinga combinedlvacuum panel and atmosph ic therma'l insulation is 'shown in Fig. 4. The form of the door showiiiri Big. 4 a lso inclueds an outer wall 25, a panel 2 4, and spacers The inner wall of the do includ' a.p,anshaped metal portion 39 which is; c fed with. porcelain enamel and is shaped to providef'a.recessed pjortion for porting; of, door structure at the perimeter of'the doorf In this form of door structure, corner braces, one of which is shown at 40, are secured to the inner face 41 of the outer wall of the door. A combined inner wall assembly including the metal wall 39 and a breaker strip section 42, which may be of any suitable material such as polystyrene or other plastic material, is secured by screws, one of which is shown at 43, to the corner braces. Blocks or spacers, one of which is shown at 44, of a material of low thermal conductivity are interposed between the combined inner wall assembly and the corner braces 40. The breaker strip section 42 is of U-shaped cross-section including a base portion 45 and two legs 46 and 47. The base portion 45 is arranged in line with a peripheral portion 48 of the inner wall 39 which extends inwardly from the central portion 49 of the inner wall 39. As in the forms disclosed in Figs. 2 and 3, the thicker portion of the door at the perimeter thereof, as indicated at 35, is filled with atmospheric insulation, such as glass fiber insulation, and this insulation surrounds the edge of the panel and reduces the edge losses.

While I have shown and described specific embodiment 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:

1. In a cabinet or the like including an outer shell and a spaced inner liner each shaped to provide a side wall and a rear wall, an insulating panel disposed in said side wall between said outer shell and said inner liner, said panel including two spaced sheet members sealed at their edges, the space between said members being evacuated, and a batt of atmospheric insulation of a thickness substantially greater than said panel, said batt being disposed in the back wall of said cabinet between said outer shell and said inner liner and extending adjacent to and overlapping an edge of said panel for .inim n e le k tween aid. mi e hell an ad ma a a d, a e

2- I f cabinet Qf' h ke immd n an outer. he nd a pac l n eah ha ed'jtq d ne a ap wall and a side wall, a fir st insulatin g panel disposed in said side wall between said outer shell and, said inner li i r a ew n v t nsr s is qssd ,1 an a Wa be ssasa d ut h l an a n r i r ash at a Pa e s ncl in two eci s! h t z e itie sv ealed at their'edges, the space between saidmernbers being evacun id ner n r. including an i inei Pw' s at the corner thereof joining said top wall and side wall he e to rs itis a a e is ast betws f id bu h l an id s i t i hi es n, pe tm s eri insulation disposed between said.outershellandsaid inner liner at said corner, said insiilation being between and overlapping the adjacent edges of 's'aid and second pe s' mi imizin 'h t' 9a. a Betw en sa d la e Shell S i ki le ne atta dfe s 3 In a cabinetor the likevinclu ding an outer shell and 'a spaced inner liner each shaped toidefine a top wall t i d i ul i Pan l ps d he the d' fl aid id wa s baw ja an cu e she la l' a jiq e l e s ve sais f anc i c din t' Q ra ed sh et niemb'si Sea e at their edges, the space between said members being etio a d aid nner ner nql dips n i sq artia th i acti n e n the p al t em? an hes d as hs s w s isie r ate at a n??- bs lvssa ai quterlsh l an sa d nn l' xitt hth s she and amis p zsr iijs lati i s tuat be we n ai st h l an saidin'ner liner at said inclined-portions, said'in'sulation being between adjacent edges of said panels and overlapping said edges for minimizing heat leakage between said outer shell and said inner liner at said edges.

4. In a cabinet or the like including an outer shell and a spaced inner liner, each shaped to provide a side wall, a rear wall and a top wall, a first insulating panel disposed in said side wall between said outer shell and said inner liner, a second insulating panel disposed in said top wall between said outer shell and said inner liner, each of said panels including two spaced sheet members sealed at their edges, the space between said mmebers being evacuated, said inner liner including an inclined portion at the corner thereof joining said top wall and said side wall thereof to provide a greater distance between said outer shell and said inner liner in this region, atmospheric insulation disposed between said outer shell and said inner liner at said corner, said insulation overlapping and extending between the adjacent edges of said first and second panels for minimizing heat leakage between said outer shell and said inner liner at said edges, and a batt of atmospheric insulation of a thickness substantially greater than that of said panels, said batt being disposed in the back wall of said cabinet between said outer shell and said inner liner and overlapping the adjacent edge of said panels for minimizing heat leakage between said outer wall and said inner liner at said edges.

5. In a cabinet or the like including an outer shell and a spaced inner liner, each shaped to provide two walls, a rear wall, a top wall and a bottom wall, a first insulating panel disposed in said side walls between said outer shell and said inner liner, a second insulating panel disposed in said top wall between said outer shell and said inner liner, each of said panels including two spaced sheet members sealed at their edges, the space between said members being evacuated, said inner liner including an inclined portion at the corner thereof joining said top wall and said side wall thereof to provide a greater distance between said outer shell and said inner liner in this region, atmospheric insulation disposed between said outer shell and said inner liner at said corners and between the adjacent edges of said first and second panels and overlapping said edges for minimizing heat leakage between said outer shell and said inner liner at said edges, a batt of atmospheric insulation of a thickness substantially greater than that of said panels, said batt being disposed in the back wall of said cabinet between said outer shell and said inner liner and overlapping adjacent corresponding edges of said panels for minimizing heat leakage between said outer walls and said inner liner at said edges, and a second batt of atmospheric insulation of a thickness substantially greater than that of said panels, said batt being disposed in the bottom wall of said cabinet between said outer shell and said inner liner and extending over the adjacent edge of said first panel for minimizing heat leakage between said outer wall and said inner liner at said edge.

6. In a cabinet or the like including an outer shell and a spaced inner liner, each shaped to provide two walls, a rear wall, a top wall and a bottom wall, a first insulating panel disposed in one of said side walls between said outer shell and said inner liner, a second insulating panel disposed in said top wall between said outer shell and said inner liner, a third insulating panel disposed in the other of said side walls between said outer shell and said inner liner, each of said panels including two spaced sheet members sealed at their edges, the space between said members being evacuated, said inner liner including an inclined portion at one corner thereof joining said top wall and said one of said side walls and a second inclined portion at the opposite corner thereof joining said top wall and said other of said side walls to provide a greater distance between said outer shell and said inner liner in these corner regions, the edges of adjacent panels extending into said corner regions, atmospheric insulation disposed between said outer shell and said inner liner at said corners and between the adjacent edges of said first and second panels and between the adjacent edges of said second and third panels and overlapping said adjacent edges for minimizing heat leakage between said outer shell and said inner liner at said edges, a batt of atmospheric insulation of a thickness substantially greater than that of said panels, said batt being disposed in the back wall of said cabinet between said outer shell and said inner liner and extending adjacent to and overlapping corresponding edges of said panels for minimizing heat leakage between said outer walls and said inner liner at said edges, and a second batt of atmospheric insulation of a thickness substantially greater than that of said panels, said batt being disposed in the bottom'wall of said cabinet between said outer shell and said inner liner and extending adjacent to and overlapping an edge of said first panel and an edge of said third panel for minimizing heat leakage between said outer wall and said inner liner at said edges.

References Cited in the file of this patent UNITED STATES PATENTS 1,518,668 Mitchell Dec. 9, 1924 2,036,781 Steenstrup Apr. 7, 1936 2,047,996 Crosley July 21, 1936 2,108,212 Schellens Feb. 15, 1938 2,164,143 Munters June 27, 1939 2,426,055 Rundell Aug. 19, 1947 2,442,204 Janos May 25, 1948 2,509,611 Philipp May 30, 1950 2,520,972 Siple Sept. 5, 1950 2,544,321 Iwashito Mar. 6, 1951 2,562,056 Norberg July 24, 1951 2,591,003 Philipp Apr. 1, 1952

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