US2164815A - Insulating means - Google Patents

Description

July 4, 1939. J. N H'ADJISKY INSULATING MEANS Filed March 22, 1935 3 Sheets-Sheet l July 4, 1939. J, N. HA'DJSKY 2,164,815

INSULATING MEANS INVENTOR.

Josep?! .acyisky July 4, 1939. ,1 N, HADJISKY 2,164,815

INSULATING MEANS Filed March 22, 1935 3 SheetS--Shef 3 ATTORN YS vparatus for heat insulation.

Patented July 4, i939 UNITED STATES PATENT oFFicE schim.

This invention relates to methods of and ap- A particular object is the construction of improved paneled insulating cell structures comprising serially arranged sheet or panel elements, which may or may not be of glass or other transparent substance, but

the construction of which is calculated to control the passage of heat in a novel .and very com.

plete manner.

An important object is to improve upon the structures disclosed and claimed in my cepending application Serial No. 651,931, filed January 16, 1933, now Patent No. 1,998,671, by providing for more complete and eiiicient insulation, better filtering of the air which passes into the cell during breathing thereof, and the provision of cell structures which are nevertheless of simpler and less expensive construction and easier to install.

Another object comprises the provision of such an insulating cell structure which even thoughv composed of transparent material, greatly resists the passage of radiant heat, as well as restricting conduction therethrough. A further aim is the provision of an improved method of 'insulation adapted to provide protection in a novel and improved manner against transmission of heat by both `conduction and radiation.

The invention further aims to provide such an insulating cell structure so arranged that un wanted condensation cannot accumulate within cell space or upon the panels, either to obscure the transparency or introduce into the cell structure moisture apt to produce. rusting or rotting.

Still another object is the provision of such an insulating cell structure particularly suitable for use in the multiple glazing of windows, which is so arranged as not only to prevent the loss of heat from within a building through the openings by conduction and convection, but to greatly retard the passage of radiant solar heat from the exterior through the windows in the summer time, and so facilitate the maintenance of reduced temperature within the bullding,vand in which, further, retardation of radiation may be effected by converting the same to wavelengths to which other parts of the apparatus are ref sistant.

Still other objects and advantages will be apparent from the following description, wherein reference is made to the accompanying drawings illustrating a preferred embodiment of my invention, and wherein similar reference numerals designate similar parts throughout the several views.

In the drawings: Figure 1 is a perspective view partly broken away of a double glazed glass air cell construction suitable for window installation and incorporating in one form the principles of the present invention.

Figure 2 is -a fragmentary front elevational view of a window frame in which is installed an air cell of the variety illustrated in Figure 1.

Figure 3 is a section taken substantially on the line 3-3 of Figure 2 and looking in the direction of the arrows.

Figure 4 is a fragmentary front elevation similar to Figure 2 but also showing a. portion of a wall supporting a steel sash in which a pair of my improved air cells are illustrated as installed.

Figure 5 is a vertical section similar to Figure 3, taken substantially on the line 5-5 of Figure 4 and looking in the direction of the arrows.

Figure 6 is a view similar to Figure 3 of a similar air cell construction incorporating three panels, indicated asl of glass, to reduce the transmission of heat by conduction.

Figure '7 is a. similar vertical section, partly broken away, indicating an adaptation of the inl vention suitable for incorporation in large windows such as the show windows of stores.

Figure 8 is a similar fragmentary section of a triple glazed embodiment.

Figure 9 is a front elevation of a windowcon struction incorporating in addition to a cell structure of .one of the varieties previously illustrated, screening means for restricting the passage of solar radiation, as well as means for cooling the radiant heat screen.

Figure 10 is a vertical section taken substantially on the line lll- I0 of Figure 9 and looking in thedirection of the arrows.

Figure 11 is a horizontal section taken substantially on the line Il-II of Figure 9 and looking in the direction of the arrows.

Figure 12 is a fragmentary front elevation similar to Figure 9 of another modification incorporating a radiant heat screen of somewhat different construction.

.Figure 13 is a horizontal section taken substantially on the liney i3-l3 of Figure 12 and looking in the direction of the arrows.

Figure 14 is a section similar to Figure 5l of a somewhat modified cell construction also suitable for installation in steel sash.

Figure 15 is a similar section of another modined construction.

/ Figure 16 is a front elevation of another modied insulating structure especially adapted for wall and other opaque` constructions.

Figure 17 is a horizontal section taken sub1, stantially on the line I'l--ll' of Figure 16 and looking in the direction of the arrows.

The cell structure shown in Figure l and illustrated cross sectionally in installed relation to a window frame 20 in Figure 3, comprises a supporting framework constituted of channeled sheet metal elements of which one extends the full length of each edge of the glass, the abutting ends being mitered to enable them to fit snugly against each other. Such channel elements are preferably formed of resilient corrosion resisting material, such as bronze, and each comprises an inbent central portion 2l and marginal channels 22--23 adapted to receive and retain the edges of the glass panels 24-25 The latter are preferably sealed in the channels by means of plastic cement or the like placed in the channels before they are tted over the edges of the glass. Fitting of the glass-into thechannels isfacilitated and the unwanted escape of the .plastic cement in such manner as to soil the glass prevented by flared edges as -2l which not only act as guides but retain any excess cement which may be displaced or squeezed out by the glass. As shown in Figure 3, the space between the retaining channels 22--23 provides another outwardly facing and larger channel adapted to receive a filter strip or the .like as 30, which may be composed of oil-soaked felt or other suitable substance. The webforming the bottom of the filter channel is preferably Vd to increasethe resiliency of the cell in compression and enable more effective sealing of its edges as well as safeguard the panels against breakage, and such web is also perforated as at 3| to provide communication, between the cell space within the channels and the exterior, through the lter strip. projects somewhat beyond the perimeter of the cell. The cushioning of thev glass is also assisted by the plastic cement 28, which is of such naturev as to remain soft indefinitely. Fora like purpose, channels 22-23 are formed of sufficient depth to leave a space 28 around the edges of the glass adapted to accommodate a bed of such plastic cement. The cement is of a character to remain plastic ind.- finitely, and accordingly the bed thereof surrounding the edges of the glass provides a permanent cushion adapted to protect the glass against breakage under strains induced by diagonal distortion of the sash or frame in which the cell is installed, such as are caused, for'example by settling of the building.

In installing such an air cell in wc'od sash or framing, I preferably utilize an arrangement such as is illustrated in Figures 2 and 3. 'Ihe frame, which is p"ovid'd with a suitable rabbet as 33 to receive and provide a clearance enlrely around the cell; is first provided with a bed of plastic cement or high gradev putty as 35 into which the cell is forced in -such manner as' to tightly seal glass 24` with respect to the frame 2l. The filter strip projectsfrom the cell sumciently to wipingly engage the rabbet when forced. thereinto, thus' clearng of putty the area occupied by the filter. Glass 24 is assumed to be that facing the side which is normally exposed to the air havingthe higher absolute moisture content,

' which is ordinarily the interior of the building.

lIt will be seen that the extent of projection of the filter strip 3U is sufllcient so that the strip,

exigesinl! the inner face of the rabbet upon'll 'I'he latter preferably sides resiliently supports the cell in position /until the putty has hardened. Where larger sized cells are used, however, wooden blocks or the like may be used for temporary support. Retaining means and putty for the cell may be provided in the form of sheet metal retaining strips 3l having their edges flanged to prevent escape of the cement or putty, framing the window opening and secured in place as by means of wood screws 38. The retaining strips are provided with vent holes 39 which act as guides or templet openings ,to assist in the drilling of Vent passages as 40, which connect the filter channel wlththeexterior of the cell structure, or more specifically, the face .exposed to the air having the lower absolute moisture content,-which is assumed in the illustrated embodiment to be the face upon which the panel 25 lies. The vents 40 are provided to allow the interior of the cell to breathe, thereby preventing the development of unduly high positive or negative pressure within the cell space. The filter provides suflicient restriction, however, to prevent simple convection or circulation under wind influence or due to relative differences of weight between the air column within the'cell and the external air. A suitable arrangement whereby cells of this type may be installed in steel sash of conventional construction is illustrated in Figures 4 and 5. Each cell is similarly fitted into the window opening provided in the sash in like fashion, and the glass 24 sealed in place, and the entire unit held bya bed of putty or plastic cement 35. The filter strip 30 is again shown as of sufficient size to engage the interior of the window opening or rabbeted portion to prevent the unwanted passage of the puty or sealing cement beyond a certain point as well as to yieldably support the cell. A glazing strip in the Aform of a small angle iron 45 is shown as extending around the interior of the window opening to reinforce the putty or cement and guard it against dislodgment, obviating the necessity of forming the putty to a sharp edge and eliminating its tendency to crumble and fall away. In view of the thinness of such steel sash it is frequently impracticable to drill or f orm vent holes along the lower muntin in such manner that they may drain by gravity, but

the purposes of the invention are' equally well served if vent holes as 40' are provided only *in` the cross muntins or vertical side members where they may be inclined downwardly to prevent the entrance of rain.

A wooden sash frame provided with a double cell or triple glazed installation of analogous.v

construction, calculated to still further greatly reduce heat transfer by conduction, is illustrated in .Figure 6. As there indicated, the cell structure itself may be similarly comprised of glass panels 2la`-25abetween which is arranged an inner panel 26a retained by an additional channel portion 28a formed in thesheet metal frame member, which is inbent between the panels as at 21a- 2lb to-accommodate a pair of filter vstrips- N-nb. The mannerl of installation in the cell being analogous, detailed discussion is believed unnecessary, but it will be observed that the space 4l between 4the filter strips 30a-30h around the channel 2l is left open to allow communication between the two cells, pressure Within which may thus equalize, and both of which may accordingly be vented to the outside by the vent passages as "a extending from the exterior to a point ap- Figures 'I and 8 show arrangements of single and double cell constructions adapted for the accommodation of larger, heavier panels, such as large plate glass show lwindows and the like. The frame 20c is indicated as of wood, sheathed with sheet metal, as at 50, and the sheathing and retaining brackets 5i are shown nailed in place. Along the bottom horizontal of the frame, supporting chairs as 53 may be arranged at intervals. These rest upon the bracket strip 5|, and each carries on its top surface resilient supporting members as '55, of soft leather, rubber or the like upon which may rest the glass receiving channels 22o-23o of the cell frame member. The latter will be seen to be formed similarly to the small frame elements previously described, and to centrally retain in like fashion a iilter strip 30e through which restricted vent to the exterior may be provided from within the cell. Such vent occurs through holes as 3io in the central cross web of the frame member, and through vent openings as 40e formed in the front retaining strips 31e, which hold the glass in place and conceal the cell supporting and filter means. An upstanding back flange carried by bracket plate 5I supports clinch nuts as 56, or other suitably tapped blocks adapted to receive screws 54 which are passed through the retaining strip thereinto and tightened to clamp the assembly in place. Inward movement of the retaining strip 31e is blocked bya front ilange 51. The space behind the inner glass 24e being sealed by cement as 35o retained by sheet metal strip portion 59 which completes the sheathing of the back wall of the rabbet and projects into engagement with the glass. It will be understood that venting from the 'interior to the outside takes place through the spaces between the chairs 53, which being spaced allow free communication between the filter strip 30o and openings 40o.

A multiplied but analogous construction providing double cell and therefore greatly increased insulation is indicated in Figure 8. -The structure of this being analogous to that shown in Figures 6 and 7 and just described, is thought to need no detailed re-description, but like parts will be seen to have been given similar reference numerals with the addition of the distinguishing character d.

While insulation of the character provided by such cell structures is an economy in that more than the cost of insulation may be saved by prevention of the loss of heat from the interior in the winter time, such insulation is even more valuable particularly in air conditioned buildings or spaces, in the summer time, when the direction of heat flow is reversed, in preventing the leakage of heat'from the outside into the interior. I propose moreover to greatly increase the insulating eilect of such cells against the ingress of heat by also reducing transference of solar radiation, to the passage of which ordinary window glass offers virtually no resistance. The insulating eil'ect of the special means hcrein to be described is of course calculated to increase the comfort oi occupants of buildingswhich are not provided with conditioned air, but I have calculated that the saving effected where conditioned air is provided is so great as to make such insulations highly profitable.

In Figure 10 I have. shown a window frame,

[designated 20, equipped with an air'cell of the general character shown in Figure l, which cell is in this view generally deslgnated'S. It is contemplated that such cell structure is formed of panels of ordinary plate or window glass 24e, 25e, which otter little or no resistance to the passage of infra red rays of the order of wave lengths from .7 to 2.6 microns. There has recently been developed, however, a glass highly resistant to the passage of infra red radiation of such wave lengths. Glass of this character is known as radiant-heat resisting glass, but will for convenience of reference hereinafter be referred to as Tt-glass. R-glass converts infrared radiation of the wavelengths mentioned into sensible heat, raising its own temperature. This heating effect must be re-radiated or otherwise disposed of, so that means must be provided for the dissipation and conduction away of the heat generated by such glass. The heating up of the R-glass presents a series obstacle and in fact virtually prevents its use by itself as window glass, as when so used the greater portion of its heat is reradiated into the interior of the building, so that the gain is negligible, in addition to which its excessive expansion due to such heating makes it diillcult to handle and liable to breakage.

The introduction of air cooling and air conditioning for summer comfort has created a great need for a window glazing construction capable of resisting the passage of solar infra red rays into" the artificially cooled space, by reason of the fact that the extraction of h'eat from air by such means is considerably more expensive per B. t. u. than is the addition' of heat in winter. The total heat gain through windows of ordinary glass when the sun shines upon it adds about 20% to the cost of both the initial in-l stallation and operation of air conditioning apparatus. In addition to this the effect of the su'n upon the glass makes it very diiilcult to maintain uniform temperature within the conditioned area as the sun aspect changes during the day. Actual tests have shown that in the summer sea'- `son in temperature climates ordinary- Window glass will be on a sunny day transmit about 190 B. t. u. per square foot per hour. Of this only about 13% passes by conduction and convection, while approximately 87% passes therethrough in the form of infra red ray radiation. rI'herefore it will be seen that While the installation of such a double glazed or insulating air cell construction composed of ordinary glass, such as was described in connection with ,Figures l to 8 hereof is a sound economy, the provision of means capable of preventing passage of even half the infra red radiation would provide a greater saving. Because of these difiiculties, moreover, a number of air conditioned buildings have been constructed without windows. Such procedure is undesirable for numerous reasons, among which is the increased cost of the lighting load added by artificial illumination throughout the entire year, and the removal of the cheerful and benecial effects of the sunlight and of an external view upon the occupants of the building.

R-glass particularly resists the passageof infra red rays of the order of the wavelengths from .7 to 2.6 microns, While the ordinary glass which I propose to provide in addition, as at 24e and 25e in Figure 10, resists the passage of rays of longer wave lengths. The R-glass is shown as supported in channel members 80 projecting from the frame' 20e in such manner as to space the R-glass panel, designated 6I, therefrom suilciently to allow air convection between the panel and the air cell glass. the top and bottom being indicated as open for this purpose, so that a natural iiue is formed by` such space. Since the ordinary glass is virtually opaque to the passage of infra red rays of wavelengths greater than approximately 2.8 microns, while the re-radiations from the R-glass due to its heating are of much greater Wave length than 2.8, such -radiations from the R-glass are blocked by the panes of the cell 36, while the R-glass in turn shields the plain glass against the shorter solar radiations to which the latter is pervious. The R-glass may be removed in winter to allow solar radiation to penetrate, for the benefits of its heating effect. For this purpose it is shown simply slidably iitted into the channels 6U.

Since good air conditioning practice calls for the maintenance of a positive pressure within the conditioned zone, in order toprevent leakage of heat laden air into such space from outside, and since such positive pressure results in some leakage of cooled air from the enclosure through whatever openings may be present, I contemplate the provision of means which may be incorporated in the'frame 20e carrying the air cell and R-glass screen, whereby such excess cooled air may escape in a manner to assist cooling of the R-glass. For this purpose a vent opening at 65 is formed in the frame above the cell-screen structure, which ventis provided with a selfclosing damper assembly, the outer damper 66 of which is arranged to act as a defiector to direct the outowing air downward and into the flue space between the R-glass and the air cell. 'I'he damper section is shown as comprising in addition to the outer member 66 an inner damper B1 articulated thereto as by a link 68. Both dampers are hinged at their tops in such manner as to be balanced to close under the influence of gravity but capable of being opened by a sufficient increase of pressure within the building. The vent dampers may be locked in closed position by some means such as the hand catch 69. In order to facilitate cleaning, the R-glass may be arranged in a hinged rather than slidable mounting.

If desired the outer glass as 25 oi' a cell structure such as is shown in Figure 3 may comprise a sheet of such radiant heat resisting R-glass while the inner sheet 2'4 is formed of ordinary plate glass or window glass. While this does not provide so great insulation against leakage into the building of the heat developed by the R-glass, and also does not allow convenient removal of the R-glass in winter, it provides a marked saving over the year, in air conditioned buildings, due to the greater cost of heat extraction and the efficiency of the insulation. The operation of such an assembly as is shown in Figure 3, incorporating at 25 an R-glass panel, will then be such that about 75% of the infra red radiation will be converted into sensible heat by the R-glass and reradiated at a wavelength which cannot pass through the ordinary glass 24 on the building side. Such heating of theR-glass will tend to raise the temperature of the air in the cell and expand it. The increased pressure will vent itself to the outside through the breather openings 40, and some. of the sensible heat imparted to the air in the c'ell will of course be imparted to the interior by conduction.. 'Ihis heat transference is materially reduced by the restricted convection currents in the cell, and each added sheet of ordinary glass by additional cell multiplication such as is shown in Figure 6 will reduce the amount of sensible heat transference toward the house. R-glass will of course be used only in the outer panel regardless of the number of cells and the expansion and contraction of the R-glass may be cared for by the cushioning space 28.

Inasmuch as the R-glass also stops about 25% of the visible light rays, it is desirable that it be -removable when not needed, as during the cooler months of the year, for which reason I consider preferably the R-glass structure first described, and shown in Figures 9, 10 and 11.

Another form in which the R-screen is mounted exteriorly in a hinged shutter frame 20j is shown in Figures l2 and 13. The R-glass is here shown incorporated in the form of vertical pivoted slats or vanes 10 through which air may freely pass to provide for ventilation of the building when the Window 1|, in front of which the screen is shown installed, is open. R-glass screens of this type will be seen to be particularly suited for use in conjunction with buildings which are not air conditioned, and the slats of the screen are preferably controllable by vmeans of a link as 13 pivoted to each slat and swingable by means of a handle as 15, which is also provided with means for securing the slats in any desired angular position. They may thus be swung to provide the desired shielding as the sun aspect changes during the day, and to close the slats` when desired. The frame 20j is preferably hinged upon a bracket 'I1 adapted to space the frame from the wall and window to allow air circulation behind the screen even when the slats are closed. It will be seen that the vertical trunnioning of the screen slats provides better visibility than would a horizontal arrangement, as well as better adjustment for changes of sun aspect. The vertical arrangement of the surfaces also allows for the best and most effective diffusion of light in the room, and further since wind movement is in a horizontal direction serves to deiiect into the room any breezes, no matter from what direction, which strike the faces of the vanes, or if the wind strikes their backs, an aspirating eifect is induced. The vertical positioning also provides for better convection of air currents about the vanes themselvesto carry away the heating eil'ect of the inf'a red rays absorbed by the R-glass, on days when there is no wind. A horizontal vane arrangement, however, is of advantage in that it provides better shielding against'rain. In some installations it may accordingly be desired (literally v'or in effect) to turn the screen shown in Figures 12 and 13 ninety degrees about a perpendicular axis, thereby disposing the slats horizontally. The projection of the bracket 11 from the building will be seen to so carry'the supporting hinge portions 18 that the screen when swung to the open position clear of the building, as indicated in dotdash lines at 8l! in Figure 13, is also well spaced from the building to allo'w for free aircirculation about all parts of the R-glass.

It will also be seen that a similar effect may be secured by utilizing, in place of R-glass, reflecting 'vanes' or slat elements of bright metal, such as trated in Figure 14, not only provides greater e flexibility and freedom of expansion for the outer pane, which is of particular value where R-glass is used for this element, but allows installation of a cell unit in exactly the same manner as a single pane o! ordinary glass. This modification possesses the further important advantage that it eliminates the necessity of drilling or 75 forming holes in the sash which is of course somethingof an expense. In this view a conven.- tional steel sash is shown, designated 20g. The outer glass panel 25g is carried in a. projected position with respect to the window frame, while the inner panel 24g may be retained, as would the single glass of an ordinary window containing but one pane, by' putty,and by a glazing guard strip 45g in addition if desired. The two panels 24g, 25g are initially assembled in a frame 2 in having a deeper retaining channel 22g for the larger glass 24g than is the retaining channel 23g for the glass 25g.: -The latter with its framing being small enough to pas through the window opening. The cross web ig of the cell frame is similarly inset to accommodate-the filter strip 30g, and apertured as at. 3 Ig in like fashion, while another iiexible frame member 90 is fitted over the frame element Zig and the retained filter strip 30g, projecting, as shown, outward from the muntin` to support the outer panel. In alignment with the edge of the panel 25g the frame element 90 may be punched as at 9| to provide flexible tongues adapted to yieldably support the channel portion 23g and the glass 25g held there'- by, as well as to provide vent openings allowing access of outside air to the filter element 30g. The larger inner panel with itsericlosing frame members ofcourse fits and is retained in rabbet 33g in the frame 20g.

It will be seen that although gaps 28g are provided by excess channel depth about the edges of the panels, which gaps may be filled with plastic cement or the like to provide cushioning against torsional stresses as well as to seal the panels in the frame, additional resiliency is afforded by the construction and arrangement of the outer frame member 90. Since both this and the inner frame -element 2| g are resilient, the outer glass may expand to an even greater degree without danger of cracking. This enables the use of an R-glass outer panel, as described above, without danger of its destruction by forces set up by' expansion and contraction.

A modification of the structure last disclosed is y illustrated in Figure 15. The glass panels 24f,

25j may in this embodiment be of the same size. They are retained in the rabbet 33j in the frame 20j by means of a folded flange 93 formed in the outer frame element 90j, which flange is ernbedded in the putty or other retaining means to provide in effect an extension of the inner panel 24j. The sash 20j is preferably formed of metal and is shown as somewhat thinner than the cell structure. This breaks the continuity of the metal of the sash, so that no integral metallic portion thereof is exposed within the building, thereby eliminating the condensation and consequent rusting of the sash frequently caused by its maintenance at a temperature below the dew point temperature of the air within the building (when the temperature outside is low enough to so reduce the metal of the sash).

The outer frame element 90j is shown as formed in halves, crimped together to provide the flange 93, and the front section is provided with punched tongues adapted to furnish air inlet openings as at #f in similar fashion to the last embodiment. Preferably the jacketing member 45j is of sufiicient width to extend over'the ed'ge of the glass and so hold the putty thereag'ainst. It will also be seen that the puttyl or cement 35j covers the sash'on the house side to provide insuiation and prevent access of moisture-laden airl to said sash, thus stillfurther greatly reducing the likelihood of condensation thereupon.

An .application of the principles of my invention to insulation where transparency is not involved, as in wall structures for refrigerated enclosures, is indicated'in Figures 16 and 17. It will be appreciated by those who have gained an understanding of the principles of my invention that its application 'to such use will prevent the ving the area whose air is normally at lowertemperature and lower absolute moisture content. Vents to this area from the celll spaces between the panels may be formed by holes as |05 extending through the uprights |03 and the sheet 99. The uprights support the panels, while spacers, as |06, interposed between the panels, are also apertured to allow air-flow between the panels. Filter units as |01 may guard the 'external -vent openings |05, and the inner and outer panel groups may be be supported by separate uprights, designated |04 -and staggered with relation to the inner uprights |03. Restricted communication will be seen to be provided from the side faced by panel 99 to all spaces between the panels, While access of air to the interior from the other side is prevented by panel |02. It will be understood that in event such arrangement is usedin the construction of walls of buildings and the like, the relative temperature conditions may reverse at different seasons of the year, but this cannot cause condensation within the walls, even should the interior be artificially cooled in summertime, because despite such artificial cooling the Walls are ordinarily at a temperature ten or fifteen degrees higher than the dew point ternperature of the outside air.

What I claim is:

.1. An insulating air cell structure comprising a main frame, a plurality of spaced substantially parallel panels, and a sub-frame supporting the panels with respect to each other and in the main frame, comprising a resilient sheet metal holding element having folded portions defining channels for embracing the edges of the panels along both sides of each panel, apertured integral transverse web portions connecting said folded portions and deformable by stress perpendicular to said panels, said web portions being spaced inwardly from the edges of said panels,.iiltering means retained between said panels and voutside said web portions, means defining vents connecting the filtering means with one side of the main frame, said connecting portions and the filtering means being held in compressed condition in the main frame.

2. An insulating air cell structure as defined by claim 1 characterized by the projection of the filtering means beyond the edges of the panels.

3. An insulating air cell structure as defined by claim 1 characterized by the projection of the filtering means beyond the edges of the panels,

and the resilient support of the sub-frame and panels in the main frame by means of said itering means.

window or the like having a rabbeted opening therein, a panel held and substantially sealed in said rabbeted opening, an auxiliary frame'extending around said opening and projecting laterally upon one side of said panel, said auxiliary frame having vents therein opening upon one side of the main frame, a second panel mounted in said auxiliary frame in spaced relation to the first mentioned panel, and filtering means carried in said auxiliary frame between said panels and guarding said vents.

5. A construction as set forth in claim 4 in which the auxiliary frame includes a channeled portion overengaging and securing the same to the perimeter of lthe rst mentioned panel and the laterally projecting portion is inset from said 'channeled portion, and proportioned to carry a second panel smaller Vthan the first mentioned panel, both panelsvbeing held in position With relation to each other by the auxiliary frame, and means for securing said channeled portion V in the main frame to .support the entire assembly with respect thereto.

6. A construction as set forth in claim 4 in which the auxiliary frame includes two relaarancia tively spaced channeled portions embracing the edges of the panels and securing the same in position with respect to each other, a portion of the auxiliary frame also forming a flange adapted to extend into and be secured in the rabbeted portion oi' the main frame, and yieldable spacing and filtering means arranged between the panels. i

7. A construction as set forth in claim 4 in which said auxiliary frame projects laterally from the main frame and the first mentioned panel, and is apertured in such projecting portions to provide communication between the exterior and the space between the panels, a compressible filter element extending around the edges of and be tween the panels and guarding said apertures, and compressible holding means for the filter element forming part of said auxiliary frame construction.

` 8. A construction as set forth in claim 4 in 9 which the projecting portion of the auxiliary frame is spaced from the main frame, and the second panel is supported by a retaining portion formed along the edge of said projecting portion.

JOSEPH N. HADJISKY.

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