US2257948A - Means for preventing moisture condensation upon refrigerator windows - Google Patents

Description

Oct. 7; 1941. I J. P. GREEN, 2,257,948

MEANS FOR PREVENTING MOISTURE CONDENSATION UPON REFRIGERATOR WINDOWS Filed Feb. 7, 1940 Patented Qct. 7,1941

8 FOR r0 MOISTUB MEAN ' CONDENSATION UPON REFRIGERATOR WINDOWS John P. Green, was... Pa. Application February I, 1940, Serial No. 317,832 18 Claims. (Cl- B289.5)

This invention relates to new and useful improvements in refrigerator construction whereby frosting or condensation of moisture on the window glass or other surfaces thereof is prevented and the pressure between the several panes of a multi-paned window is brought and maintained closely to atmospheric thus eliminating the danger of moisture infiltration because of external leaks.

More particularly the invention relates to the 1 prevention of frosting and condensation on multipaned windows of low temperature refrigerators such as those used for the-storage and display of frosted or frozen foodstuffs and the like.

The invention also involves the provision of an arrangement whereby display refrigerators can be glazed without the use of special rooms in which atmospheric conditions are maintained in. order to prevent the inclusion of air of high moisture content between the of the window, and enables, further, the elimination of the necessity for using chemical moisture absorbing compounds in order to remove any moisture occluded between said panes or exuded by the framing material or the materials used in glazing the refrigerators.

' such a construction objectionable moisture has been found to be depositedon the panes due to the fact that their outer surface temperatures are at times below the dew points of the air in contact therewith. I

In addition to the formation of frost or conatmosphere surrounding the refrigerator upon the exterior surface of the outer pane of the muiti-paned window in said refrigerator.

with these and other objects in view, the invention consists in the various features of construction, combination and arrangement of parts hereinafter fully set forth and shown inithe accompanying drawing, in which:

Figure l. is aview in perspective of one form of refrigerator of the display type embodying the present invention;

Figure 2 is an enlarged fragmentary sectional perspective view of the window construction of the refrigerator shown in Figure 1; and

Figure 3 is a fragmentary view in perspective showing a modification of one feature of the obliquely disposed display window 2 in thefront of the refrigerated chamber thereof.

As shown in Figure 2 of the drawing the window 2 is comprised of four spaced panes of glass 3, l, 5 and 8 mounted within a frame I and spaced from each other by'suitable sealing strips 8 and 9 respectively, to form insulating air spaces ii, I! and it between said panes I, l, 5 and B, the outer pane 6 being sealed against the infiltration of air. from the exterior of the case by a suitable sealing compound it held in place by strips Illa.

As the air within the refrigerator has been cooled to a temperature 'below that existing between the several panes of the window, such air will, if permitted to circulate in proper amount through the aforesaid air spaces ii, i2 and I3, not only fail to precipitate moisture but will absorb any moisture within these spaces with the densation upon the panes, another difficulty is 40 result that condensation upon the surfaces of present due to the condensation of moisture upon the exterior surface of the outer pane when, under certain climatic conditions, the dew point ofthe air in contact with the outer surface of this outer pane is exterior surface of this outer pane. This occurs in times of high relative humidity of the atmosphere in the room or place where the refrigerator is located.

with the foregoing observations in mind, the object of the present invention is to provide a multi-paned windowfor a lowtemperature refrigerator so constructed and arranged as to maintain vair having suiliciently low relative humidity in contact with the surface or surfaces of said panes that moisture or frost will not be deposited on the surfaces of said panes.

A further, but equally important object of this invention is to provide a novel means for preventing the condensation of moisture said panes is entirely eliminated and unobstructed" clear vision therethrough to the interior of the case is insured at all times.

In order effectively to accomplish this, the botabove the temperature of the 45 tom frame member la is provided with a series of spaced grooves or slots i4, i5 and i8, and these are so located and spaced with respect to each other and the panes of glass 3, 4, 5 and 6 that they are respectively disposed centrally below or at the bottoms of the insulated air spaces il. l! and I3 between the said panes. Similarly the top frame member 11) is provided with like grooves or slots II, II and I! which reside respectively at the tops of said insulated air spaces H, II and I3.

To provide for communication between the several grooves or slots I4, I! and it and the respective insulated air spaces i i, i2 and .II, the bottom insulating and spacing strips I are each from th provided with suitable openings to, 8b and 9c therethrough which respectively register with the said grooves or slots l4, l3 and ll, Likewise the top insulating and spacing strips 3 are pro vided respectively with openings 3a, 3b and 30 which respectively register with the grooves or slots l1, l3 and I! in the top frame member 1b.

In order to permit air from the interior of the case to enter the space l2 between panes 4 and 3, I provide an opening 20 to the central groove or slot II in the bottom frame member or portion la, and also provide a second opening or slot 2i which communicates inwardly with said duct 23 i thus providing dual air openings to the said groove or slot II and insuring continued circulation should one or the other of them become obstructed due to foreign objects coming in contact therewith.

In order to prevent any infiltration of dust or other foreign matter to the insulating air spaces ii, l2 and i3, the aforementioned central groove or slot It, or the opening 20, is packed with a loose porous material 22 saturated or coated with a non-drying liquid substance such as calcium chloride or the like or with a substance or material having suitable adhesive properties such as, for example, Vaseline.

Between the grooves or slots l1 and i3 and providing communication between spaces II and- I2 is a duct or ducts 23 formed in the upper frame member lb. Likewise between grooves or slots l4 and i6 and providing communication between the spaces II and I3 is a duct or ducts 24 formed in the bottom frame member Ia. In addition, and to provide an outlet to the interior oi the case from the space 13 a duct or ducts 2! is formed in the upper frame member lb so as to communicate between the slot l3 andan outlet slot 20 formed or provided along the upper interior surface of the innermost pane of glass 3.

In order to obtain optimum results from the invention too great emphasis cannot be laid upon the location of the outlet opening 26 of the return duct 25 to the interior of the refrigerating chamber in order to prevent stoppage of said opening due to the collection and freezing chamber at a point or points immediately ad-' jacent the top interior surface of the innermost pane 3 as indicated at 26, the air preferably actually passing in' contact with the surface of said pane 3.

If necessary, in order further to protect the outlet of the return passageway or duct 25 from the low temperature of the refrigerating chamber and insure maintenance of the surface of this pane 3 above the dew point of the returning air, a shield 21 may be disposed .along the interior of the top frame portion so as to depend therebelow and overlie the outlet of said return duct 25, said shield, however, should not depend a distance which will reduce materially the field of vision through the window 2.

outlet adjacent the upper interior surface of the pane 3 as aforesaid, it is pointed out that the said air may be returned as indicated at 20a (dotted lines) to any point or zone within the refrigerator wherein the temperature is above the dewpoint of said air, and with equally satisfactory results, as for example, by extending the return air outlet into the interior of the cabinet and artificially heating the outlet, as indicated at 23, either electrically orby the hot compressor gases or by extending the said return air outlet into the warmer temperature zone just above the expansion unit which is present in all artificially cooled refrigerators.

Now, in illustration 'of the invention, as the air within space l2, under operating conditions, will be at a higher temperature than the air within the cabinet, there will exist a slight pressure difference between opening 3b and the inlet openings 20 and 2| with the result that air from within the cabinet is drawn into the insulating space i2 causing the air therein to be displaced slowly upward and outwardly therefrom through the opening 8b. As the air thus entering the space i2 is raised in temperature, its relative humidity is lowered and any moisture within the said space l2 will be absorbed'and will not be deposited on the surfaces of the panes of glass 4 and I.

. Similarly, as the air ,within the space H is at a lower temperature than the air within space l2 there exists a sufficient pressure differential between openings 3b and 3a to cause air within the space i2 to be forced into said space i I and displace the air in that space downwardly and out of the opening 30. As this air which is forced into the space Ii is at a temperature sumciently higher than when in the refrigerated case the said air will be above the dew point and no moisture will be deposited on the surfaces of:the panes 3 and l of the'window.

Finallyyas the air within space I3 is at a higher temperature than the air in space H, a pressure difference will exist between the openings 3a and 30 with the result that air from space II is caused to flow through passage 24 and upwardly through slot i6 into space l3 forcing the air therein to be displaced upwardly outwardly through opening 30, groove i9 and passage 25 from which it is returned to the interior of the cabinet through the outlet opening 23.

Now as respects the prevention of moisture condensation on the exterior surface of the outer pane 6 under certain climatic conditions, I have found that if, during periods of such conditions, said exteriorsurface of the outer pane 3 is heated to or maintained at a temperature equal to or above the dew point of the atmosphere in which the refrigerator is located, this condensation of f moisture can be successfully eliminated.

While, for purposes of economy in construc- Therefore, according to the present invention, I dispose a heating element or means 23 along the exterior of the outer pane 8 and in contact with the exterior surface thereof, preferably near an edge as shown in Figure 2 of the drawing. This heating element or means 23 may, for example, be either a resistance element through which a suitable electric current is passed or may be a pipe or conduit through which the hot refrigerant from the compressor passes. As hereinbefore stated this condensation condition does not continuously occur and therefore the heating element or means 28 need be operated onlywhen it is necessary to keep the temperature of the exterior surface of the outer pane 8 above the dew point of the surrounding; atmosphere. Of course. while the heating element It is shown as located adjacent and along the lower or bottom exterior edge of the outer pane of glass 6, it will be obvious that such position is not essential and that such heating element may be placed adjacent to and alongi any one or more edge or other exterior surface portions of said outer pane 6 with satisfactory results.

From the foregoing it will be observed that the present invention provides a refrigerator window construction and arrangement whereby moisture condensation on the several panes of said window may be successfully and entirely eliminated,

and that said construction and arrangement by which such results are obtained is relatively simple and inexpensive although it is comparatively rugged.

Although the descriptiongand illustration of the invention have been-shown as applied to a four-paned window, it will be obvious, of course,

that only three or even a greater number of panes may be employed vby a repetition of the circulation in the case of aneven number of a ing air.

refrigerating chamber in a zone therein having a temperature above the dew point of said return- 4. In a refrigerator having a display window in the refrigerating chamber thereof comprising a plurality of panes of transparent material 5. In a refrigerator having a display window in' the refrigerating chamber thereof comprising a plurality of panes of transparent material spaced from each other to provide a plurality of insulating air spaces therebetween, air passageways panes, or by connecting any two adjacent air spaces so that for all practical purposes there exists an odd number of circulating spaces in the case where an odd number of panes is employed.

Also, while a particular structural embodiment of the features 'and details of the invention has been illustrated and described it is not intended that the invention be limited thereto but that changes and modifications may be incorporated and embodied therein as desired within the scope of the annexed claims.

I claim:

' 1. In a refrigerator havinga display window in the refrigerating chamber thereof comprising a plurality" of panes of transparent material spaced from each other to provide a plurality of insulating air spaces therebetween, an air passage from said refrigerator chamber to th insulating air spaces, and a return air passageway from said insulating air spaces opening to the refrigerating chamber at a .point adjacent the upper edge portion of the interior surface of the inner pane of transparent material. I

2. In a refrigerator having a display window in the refrigerating chamber thereof comprising a plurality of panes of transparent material spaced from each other to provide a plurality of insulating air spaces therebetween, an air passage from said refrigerator chamber to the in-- sulating air spaces, and a return air passageway from said insulating air spaces opening to the refrigerating chamber at a point adjacent the upper edge portion of the interior surface of the inner-pane of transparent material, and means for heating the exterior surface of the outer paneof transparent material disposed along an exterior surface portion thereof.

3. In a refrigerator having a display window in the refrigerating chamber thereof comprising a plurality of panes of transparent material spaced from each other to provide a plurality of insulating air spaces therebetween, an air pas-. sage from said refrigerator chamber to one of the insulating air spaces, other air passages communioating between said insulating air spaces and arranged so that air from the chamber will flow through the spaces in predetermined sequence, and a return air passageway from the air space last in said sequence opening to the providing communication serially between said insulating air spaces, an air passage ffom said refrigerator chamber to an outer one of the insulating air spaces, a return air passageway opening tolthe refrigerating chamber at a point adjacent the upper edge portion of the interior surface of the inner pane of transparent material, and means for heating the exterior of the outer pane of transparent material disposed along an exterior surface portion thereof.

6. In a refrigerator having a display window in the refrigerating chamber thereof comprising a plurality of panes of transparent material spaced from each other to provide a plurality of insulating air spaces therebetween, air passageways providing communication serially between said insulating air spaces, an air'passage from said refrigerator chamber to an outer one of the insulating air spaces, and a return air passageway opening to the refrigerating chamber in a zone therein having a temperature above the dew point of the returning air.

'7. In a refrigerator having a display window in the refrigerator chamber thereof comprising four panes of transparent material spaced from each other to provide inner, intermediate and outer insulating air spaces between respectively adjacent panes; an air passageway providing communication from said refrigerator chamber to said intermediate insulating air space, other air passageways providing communication from the intermediate to said inner and from the innerto'said outer air spaces respectively, and

a return air passageway from the outer air space to the refrigerator chamber opening to the latter at a point adjacent the upper edge portion of the interior surface of the inner pane of transparent material.

8. In a refrigerator having a display window in the refrigerator chamber thereof comprising four panes of transparent material spaced from each other to provide inner, intermediate and outer insulating air spaces between respectively adjacent panes, an air passageway providing communication from said refrigerator chamber to said intermediate insulating air space, other air passageways providing communication from the intermediate to said inner and from the inner to said outer air spaces respectively, return air passageway from the outer air space to the refrigerator chamber open ng to the latter at a point adjacent the upper edge portion of the interior surface of the inner pane of transparent material, and means for heating the exterior surface of the. outer pane of transparent material disposed along an exterior surface portion thereof.

9. In a refrigerator having a display window in the refrigerator chamber thereof comprising four panes of transparent material spaced from each other to provide inner, intermediate and outer insulating air spaces between respectively adjacent panes, an air passageway providing communication from said refrigerator chamber to said intermediate insulating air space, other air passageways providing communication from the intermediate to said inner and from the inner to said outer air spaces respectively, and a return air passageway from the outer air space to the refrigerator chamber opening to the latter in a zone therein having-a temperature above the dew point of the returning air.

10. In a refrigerator having a display window in the refrigerating chamber thereof comprising a plurality of panes of transparent material spaced from each other to provide a plurality of insulating air spaces therebetween, an air passage from said refrigerator chamber to the insulating air spaces, and a return air passageway from said insulating air' spaces opening to the refrigerating chamber at a point adjacent the upper edge portion of the interior surface of the inner pane of transparent material, and a protective shield disposed within said chamber and overlying the opening of said return air passageway.

11. In a refrigerator having a display window in the refrigerating chamber thereof comprising a plurality of panes of transparent material spaced from each other to provide a plurality of insulating air spaces therebetween, an air passage from said refrigerator chamber to the insulating air spaces, a return air passageway from said insulating air spaces opening to the refrigerating chamber at a point adjacent the upper edge portion of the interior surface of the inner pane of transparent material, a protective shield disposed within said chamber and overlying the opening of said return air passageway, and'means for heating the exterior surface of the outer pane of transparent material disposed along an exterior surface portion thereofl 12. In' a refrigerator having a display window 'in the refrigerator chamber thereof comprising four panes of transparent material spaced from each other to provide inner, intermediate and outer insulating air spaces between respectively adjacent panes, an air passageway providing communication from said refrigerator chamber to said intermediate insulating air space, other air passageways providing communication from the intermediate to said inner and from the inner to said outer air spaces respectively, a return air passageway from the outer air space to the refrigerator chamber opening to the latter at a point adjacent the upper edge portion of the interior surface of the inner pane of transparent material, and a-protective shield disposed within said chamber and overlying the opening of said return air passageway.

13. In a refrigerator having a display window in the refrigerator chamber thereof comprising four panes of transparent material spaced from each other to provide inner, intermediate and outer insulating air spaces between respectively adjacent panes, an air passageway providing communication from said refrigerator chamber to said intermediate insulating air space, other .air passageways providing communication from the ntermediate to said inner and from the inner to said outer air spaces respectively, a return air eway from the outer air space to the refrigerator chamber opening to the latter at a point adjacent the upper edge portion of the interior surface of the inner pane of transparent material, a protective shield disposed within said chamber and overlying the opening of said return air. eway, and means for heating the exterior surface of the outer pane of transparent material disposed along an exterior surface'portion thereof.

14. In a refrigerator having a display window in the refrigerating chamber thereof comprising a plurality of panes of transparent material spaced from each other to provide a plurality of insulating air spaces therebetween, an air passage from said refrigerator chamber to the insulating air spaces, a porous filter in said.air passage, and a return air passageway from, said insulating air spaces opening to the refrigerating chamber at a point adjacent the upper edge portion of the interior surface of the inner pane of transparent material.

15. In a refrigeratorv having a display window in the refrigerating chamber thereof comprising a plurality of panes of transparent material spaced from each other to provide a plurality to the refrigerating chamber at a point adjacent the upper edge portion of the interior surface of the inner pane of transparent material.

16. In a refrigerator having a display window in the refrigerating chamber thereof comprising a plurality of panes of transparent material spaced from each other to provide a plurality of insulating air spaces therebetween, an air passage from said refrigerator chamber to the insulating air spaces, a filter in said air passage composed of porous material coated with an adhesive substance, and a return air passageway from said insulating air spaces opening to the refrigerating chamber at a point adjacent the upper edge portion of the interior surface of the inner pane of transparent material.

17. In a refrigerator case maintaining subfreezing temperatures therein and having a window consisting of a plurality of spacedpanes of the air thereto at a point therein maintained at a temperature above the dew point of the said air.

18. In a refrigerator case maintaining subfreezing temperatures therein and having a window consisting of a plurality of spaced panes of transparent material, the method of preventing frosting and condensation on the several panes I of said window comprising circulating air from the refrigerator case through the several spaces between said panes, returning said air to said refrigerator case, and protecting the return air outlet so as to maintain the temperature thereof above the dew point of the air.

JOHN P. GREEN.

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