CA1113789A

CA1113789A - Multiple glazing units

Info

Publication number: CA1113789A
Application number: CA317,004A
Authority: CA
Inventors: Tilman L. Weinlich
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-11-29
Filing date: 1978-11-28
Publication date: 1981-12-08
Also published as: GB2011985A; DE2753127A1; CH636164A5; DE2827153A1

Abstract

ABSTRACT
The present invention relates to a multiple glazing unit. The unit is comprised of at least two panes and a frame which is comprised of at least two frame portions. The frame portions have mutually confronting profiled surfaces. At least one film is secured to a respective frame portion so as to extend between and be substantially parallel to the panes. The film is stretched between adjacent frame portions upon the pulling action of the confronting profiled surfaces when assembling and pressing together the at least two frame portions.

Description

1~137~

D~SCRIPrION
"IMPROV~MEN~S IN MUITIPLE GLAZING U~ITS".
The invention relate~ to multiple glazing unit~
and to a method of manufacturing ~ame. ~he present invention relates particularly to methods of stretching films disposed between pane~ in multiple glazing unit~, which unit~ may be suitable as thermal insulating unitq and/or sound proofing units, and as cover~ for collector plates for low-temperature solar collectors, etc.
Double glazing units and in~ulating glazing units whose edges or frames are hermetically sealed, and double glazing units and insulating glazing units with water vapour inhibiting sealing and with desiccants in the edge region are known (for example, in U.Reitmayer, "Holz-fenster in handwerkliche Eonstruktion" /Manually constructed wooden windows7 Stuttgart, 1956, pages 56 to 59). Furthermore, in double glazing units, it i9 known to avoid misting of the i~ner surface of the panes by connecting the interior space of the unit to the outer atmosphere 90 as`to permit the pa~sage of water vapour, either the air being circulated, or the vapour pressure , . . ~ .

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being equalized by diffusion. Valves for the equ~liz-ation of the vapour pre8sure and/or dust filters are used which are fitted in the frames (see German Patent Specification No.376,211 and German Patent Specification 5 No.504 560). In addition to serving for the circulation of air to avoid deposits of condensate, the openings ~i provided in the last-mentioned Patent ~pecification also serve for introducing a cleaning implement which, for example, can remove dust. ~;
Furthermore, it is known to use one or a plurality of plastic~ pane~ in multiple glazing units (see German Patent Specification No.638 327), or to use coatings which are reflective in the infrared range (see German t Patent Specification No.689 524; German Utility Model No.16 95 387 and German Patent Specification ~o.l 079 291).
It is also known to seal the space between the panes in an air-tight manner and to fill it with a gas which is ;, denser than air in order to reduce the thermal conduction.
It is known from H. Leuder "Energiehanshalt im r' 20 Hochbau" (Energy economy in building construction, Zurich 1976, page 57, to stretch several highly trans-parent film8 which are located between the panes.
Furthermore, it has already been proposed to dispose a ;
vapour-deposited film between two panes, and to fill the cavities between the panes with a gas (see German Offenlegungsschrift No.2 263 353), or to stretch one or several film8 bétween vapour-deposited films (see ~ German Offenlegung8schrift No.2 443 390). In 80me case~

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the inside surfaces of the panes and/or the films have been coated with a silicone-based material 80 that, if the spacing and sealing means between the panes ~hould become defective, the condensate i8 deposited on the spacers and not on the ~urfaces of the glass or the films.
By way of example, the following measure~ have been proposed for sound-proofing in connection with the glazing: thick panes, several panes of dif~erin~ thick- -nesses, filling with light or dense gaqes, increasing the distance between the panes, sound-absorbing materials in the spacer or on the qpacer (see G~sele/Sch~le) "Schall, i Warme, Feuchtigkert" (Sound, heat, moisture), Berlin-Weisbaden, 1977, pages 80 and 81), avoiding the trans-mission of ~ound acros~ the spacer by damping in the Juncture region between the spacer and the glass and in the spacer (see German Offenlegun~sschrift ~o.2 445 332), and combinations of these measures.
~he known double glazing units and insulating glazing units result in a relatively small advantage with respect to the small k-value, that is to say, the standard measurelof the heat-insulating properties of glazing or the heat transmission value, when such improvements areirelated to the additional costs. ~he , glazing unit i8 rendered relatively complicated and is thus expensive when several measures are undertaken in order to i~prove the glazirg unit. ~he ~a~u~acturirg .)~

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co~ts are increased particularly by the cost of applying ~ubstances to the glass panes by vapour deposition.
~he glass constructions are rendered even more expen~ive when they have an hermetically sealed edge for the introduction of noble gases. The hermetically sealsd edge gives rise to considerable problems when a high k-value is required in conjunction with a large pane format, since the deflections and movements which have to be absorbed by the edge or by the frame increase as the edge length increase~ and the temperature difference between the inner and outer panes increases, this temperature difference becoming greater in conformity with a good k-value. ~hus, her etic sealing of the edge not only lead~ to high costs and frequent cases of damage due to the many mechanical stresses of the edge connection or frame connection during transport, by fluctuations in air pre~sure, noise, temperature fluct-uations and by actuating the windows, that is to say by opening and closing the windows. When using desiccants, saturation of the desiccant3 occurs very early, frequently shortly after expiry of the guarantee period, 80 that the interior of the panes can only be kept free from conden~ate for a relatively short period of time.
~hus, it wa~ necessary to arrange the pane~ at only a relatively shor~ distance apart. Furthermore, hermetic sealing of the edge is al~o problematical in view of the acoustic coupling of the glass panes, and in view of the ¦~

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~$1;~7~-3 heat bridge occasioned by the spacing and sealing means.
If spacers capable of diffusion are used, it has transpired that this solution only functions satisfactorily when the panes are not subjected to direct solar irradiation.
The use of films has hitherto been precluded by the fact, that hitherto, highly transparent films which are adequately resistant to ultraviolet radiation have not been available. Furthermore, it is extremely difficult to introduce the films into the glazing unit parallel to the panes at a reasonable expense.
In accordance with one aspect of the invention there is provided a method of stretching at least one film located between two panes comprising the steps of: (a) providing at least two frame portions for forming a full frame, (b) providing said at least two frame portions with mutually confronting profiled surfaces, (c) securing each film to a respective frame portion, (d) assembling said at least two frame portions to form the full frame, and (e) pressing together said at least two frame portions to stretch the film by the coaction of the confronting profiled surfaces of adjacent frame portions.
In accordance with another aspect of the invention there is provided a multiple glazing unit comprising: (a) at least two panes, (b) a frame comprising at least two frame portions, (c) mutually confronting profiled surfaces on said at least two frame portions, and (d) at least one film, each of which is secured to a respective frame - '.'' : - . . :
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- 5a -portion, so as to extend between and be substantially parallel to the panes and stretched between adjacent frame portions of said at least two frame portions upon the pulling action of the confronting profiled surfaces on said at least one film when assembling and pressing together said at least two frame portions.
The inventor of the present invention has conducted exhaustive experiments for the insertion and shrinking-in of films and considers the hitherto proposed methods to be reliable and possible, but too expensive in practice, so that glazing units with films cannot be manufactured economically. -In addition to the changed awareness of the energy problem, the changed conceptions with respect to reasonable nuisance caused by noise also requires improvedi~ound proofing properties in glazing units. Hitherto, there has been no inexpensive solution to the two problems.
A plurality of relatively thick panes only results in satifactory k-values in sound-proofing glazing units, when optimum distances between the panes are observed.
This results in relatively heavy and thick glass ~ .

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''' ~ ''- . ' ' ' ' ' - 6 - ~ `7 assemblies which are not only expensive themselves but are also expensive to install. The edge of the glass or the frame has to be reinforced in the case of hermat-ically sealed space~ between the pane~, since the great weight of the panes otherwise does not permit the frame to be sealed hermetically. ~hus, the insulating glazing units known hitherto have not lent themselves to the manufacture of large area glazing units without giving rise to an unphysiological room atmosphere which is caused by the low surface temperatures of glazing units of this type and which cannot be eliminated by heating technology.
~ herefore, an object of the invention is to provide methods which render it possible to manufacture very satisfactory thermally insulating and satisfactorily ~ound-proofing glazing units for facades and glazing in a very inexpensive manner, even in the case of diverse and difficult structural and design conditions. A further object of the invention iB to provide arrangements having multiple units, such a~ double and multiple windows, by means of which it ji8 possible to seal the edges hermet-icall~ in an ine ~ lensive manner and which can be manu-factured in a simplle manner, and also enable the panes to be at greater distances apart, wherein the edge connection is to avoid acoustic coupling of the panes and a heat bridge. Moreover, the interior spaces between the panes are to remain free from condensate and dust, and ~¦

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~ he present invention provide~ a method of ~tretching at lea~t one film located between panes, in which a frame is formed from at least two frame portions, the mutually confronting ~urfaces of the frame portions are profiled, the film i8 secured to one individual frame portion, the individual frame portions are assembled to form the full frame, and upon the pres~ing-together of the frame portions, the film is stretched by the confronting profiled 10 Qurface on the frame portion adjacent said one frame ¦~
portion.
~ hus it is possible to manufacture, in an inexpensive and reliable manner, glazing unit~ having relatively smaller distances between the panes, irrespective of the existing installation conditions. Highly transparent films or, alternatively, films provided with a coating which reflects in the infrared range, can be inserted, one between each two adjacent panes or several parallel to one another by securing the films to a respective frame portion, and then stretching the films by pressing the profiled surface on the mating frame portion thereagainst.
If required,~intermediate pa~es, which absorb the tensile forces of the films, can be additionally used for support purposes. ~he frame portions, which form a spacer or spacing and sealing means have to be pressed together in order to tension the films. ~hiQ is effected b~ fir3t brirgirg tho framo portior~ clo~o togother by a ~ ' .
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1~13 ~ _9 pre~s and then interconnecting them in this position.
Differing profiling of the frame portions re~ults in a desired differing initial ~tress, 80 that differing resonances are thus produced. The spacer can abut against the edge of the glass and form a protection for the edge. ~lternatively, a ~trip, ~uch a~ is normally used a~ a protection for the edge of insulating glazing units, can be used which holds the glass panes in this state. ~his results in a compact in~ulating glazing unit which can be fitted in a rabbet in an outer frame and sealed thereto in a conventional manner.
Thus, the method in accordance with the in~ention results in an advantageou~ insertion facility in which the films are arranged between the panes in a flat and parallel manner. A wide variety of window formats can be manufactured by the method in accordance with the invention without expensive apparatus and with low labour costs.
~he invention includes a multiple glazing unit comprising at least two panes, a spacer supporting said panes in spaced parallel relationship and comprising at least two frame portions, mutually confronting profiled surfaces on the frame portions, and at lea~t one film which i5 secured to a respective one of said frame portions 80 as to extend between and substantially parallel to the panes and which i~ stretched under the i -action of the confronting profiled surface on the . .
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adjoining frame portion when assembling and pressing together the frame portions.
If the films have a coating which i8 reflective in the infrared ran~e, it is advantageouQ for the coating to be sufficiently thin to avoid discernable discolour-ation as might be effected by ulta-violet radiation.
The structural dimensions can be optionally chosen in accordance with the criteria with respect to sound and heat technology, and in accordance with the economic and degign criteria.
When the multiple glazing unit is held in place in a suitable opening, e.g. in an outer frame, b~ means of a glazing strip of conventional width, as i8 the case, for example, of measures for the protection of monuments, ;~
15 a narrow edge construction can be chosen which i9 either -~
hermetically sealed, or is constructed with a desiccant.
A particularly inexpen_ive solution resides in constructing the spacer, which is constituted by at least some of the frame portions, 80 as to be permeable to vapour.
~his i8 possible if the glazing strip is well ventilated, such as is necessary in the case of back-ventilated ¦~
facades and cold~rooves. Advantageously, only that t ' portion of the glazing strip which faces the interior of the building is filled with an in~ulating material capable of diffu~ing vapour, and the outer portion i~
ventilated. Thus, the accumulation of condensate is avoided over a long period of time. Thus, upon a fall ~,.. i , .
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in outside temperature, the quantity of condensate is only of the order of magnitude of a milligramme. A
silicone coating on the inner surface of the glass panes and/or on the film or films, prevents the conde~sate from being precipitated on the transparent surfaces. A low ~ervice temperature of the frame in the same air chamber causes the condensate to be precipitated on the frame and not on the transparent surfaces. A material having a large active surface in the spacer can bind this quantity of moisture until steady temperature conditions prevail again. This function can be jointly undertaken by a material which dissipates sound energy, and which is fitted to improve the soundproofing qualities.
In order to reduce the conduction of sound by the spacer, the spacer, that is to say, at least some of the frame portions, can be resiliently attached to the glass panes. For the same purpose, the window construction or facade construction which presses the gla~s together can transmit its forces resiliently. Ihe resilient connection thus produced can also compensate for the differential movement~ of the panes and the facade.
As already mentioned previously, differing suitable tensioning of the individual film or films can be effected by appropriate shaping of the profiled surface~
differing natural resonances being imparted to the film or films i~ this manner, 80 that noi~e surges do not ~,~

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1~1; Fi~,3 occur at resonant frequencies in the case of air sound-proofing.
When reglazing, the glass can be secured by clips or tongues mounted on the spacer. ~he frame portions can be assembled from prefabricated profiled bar sections or, alternatively, they can be subsequently profiled. Furthermore, it i8 possible, in an advant-ageous manner to use prefabricated profiled bar sections and prefabricated corner pieces which are assembled to form the rrame portions. It is particularly advantageous to manufacture a kind of sash or frame according to the format of the panes, and to construct the individual frames therefrom.
According to the installation conditions, it can be advantageous for the edges of the panes to project beyond the spacer, to terminate them with the spacer, to ~l border them with the spacer or for the panes to pro~ect 3j individually or to differirg widths beyond the edge of ~¦
the spacer.
~he above-mentioned preferred features of the t.
invention permit the manufacture of inexpensive insulating and glazing units with inserted films, a technically and economically advantageous solution resulting from the very good heat insulating properties with the use of films which are reflective in the infrared range. Owing to the simple design, the spacer construction allows great variability and thus adaptability to differing ,.

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1~$3`7~:3 applications, so that this also renders it possible to obtain economic glazing.
~here is no need to provide the panes with very expensive coatings which are reflective in the infrared 5 range, and, furthermore, several films can be inserted in an inexpensive manner, so that it is possible to dispen~e with a gas filling and a hermetically ~ealed edge con~truction. By way of example, a 8mall k-value of 0.6 (Kcal/m h degrees) was measured in the case of 10 an insulating glazing unit sample, con~tructed in accordance with the invention, having two films and without a gas filling, 4 mm window glass being used.
~he very inexpensive insertion of the films also rendered it possible to use several films having very thin coatings 15 which are reflective in the infrared range, 90 that the energy absorption of the films is very low. ~hus, it r is poQqible to obtain a neutrally coloured tran~parency, without impairing the k-values.
In accordance with a particularly advantageous dev-20 elopment of and/or modification to the invention, air rilters are provided which are arranged between the outer pane and the inner pane in glazing units without film8, and between the outer pane and the first film in the case of glazing units having at lea~t one film.
25 ~he air spaces between the outer pane and the inner pane, or between the outer pane and the outermost film are ventilated by means of these air filters? Advant-- -- . . ... ..
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~S13~ 9 ageously, the air filters should be arranged in the horizontal portions of the frame~, and should be .
impregnated to render them water-repellent and to enable them to trap dust. Spun glass fabrics, through which insects cPnnot penetrate into the interior space of the window, is a very advantageous material for the air filters.
In accordance with a further advantageous development of the invention, in which the spacer formed by at least 10 some of the frame portions i8 moisture permeable, the `!
glazing unit is held by a ventilated surrounding frame portion which protects the spacer, the air filters and the thermal insulation and renders it possible to install the multiple glazing unit irrespective of the thickness of the casement and to provide it with an adequately ventilated glazing strip.
~he ventilation openings in the ~entilated glazing strip are disposed such that the ingress of moisture of ~¦
condensation is largely prevented and any water which penetrates can flow away directly.
The flow of air through the air space behind the outermost pane takes place primarily during exposure Or the pane to direct sunlight since the coating reflect-ive in the infrared range is heated to a considerable extent owing to the absorption of light, and a consider-able amount of lift occurs which overcomes the high flow resistance in the air filters and in the narrow openings `

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which are required for acou~tic reasons. For acoustic reasons, the interior of the spacer and the interior of the ventilation profiled sections can be lined with a sound-absorbing material.
The ~urraces of the films ~acing the outside can be provided with a metal coating which protects the films against ultraviolet radiation.
A desiccant i9 not required in the embodiment of the multiple glazing unit having air filters, so that no problems arise on guarantee expiry. Furthermore, it i9 unnecessary to provide a hermetic edge seal, so that, here also, no difficulties arise with respect to the guarantee, and a rigid connection with its inherent disadvantages is not required. In this manner, it is po~sible to provide a wider, lighter spacer which, in the case of a coating which reflects in the infrared range, and without a special gas filling, results in a `~
k-value which exceeds that of modern insulating glasses. il ~hus sati~factory sound-proofing values are obtained even !
with relatively thin panes.
~he invention is hereafter further described by way ¦~
of example, with reference to the drawings, in which:
Fig. 1 is a fragmentary sectional view of an embodiment of an air filled double-glazing unit, in accordance with the invention, having two film~ which are reflective in the infrared range and having a vapour-barrier, a desiccant and enhanced sound-proofing, the spacer being acoustically decoupled and not constituting ~ : ~
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a heat bridge, Fig. 2 i~ a ~imilar view of an embodiment of a gas-filled double-glazing unit having an infrared-reflective film, a vapour barrier, a desiccant, and small installation dimen~ions, Fig. 3 is a cro~ section through the bottom edge of another embodiment of a glazing unit, and air filter being provided in the said edge, Fig. 4 is a fragmentary cross section through a further embodiment of the bottom edge of a glazing unit and, Fig. 5 is an elevation of a side edge seal having a ventilation opening.
In the embodiment of double-glazing unit illustrated 5 in Fig.l, two gla~s panes l, 2 are attached respectively to two outer frame portions 5,6 by way of resilient connection members 3 and 4. ~he resilient connection member~ 3 and 4 enable the panes 1 and 2 to be attached to the frame in a sound-proofing m~nner, and also permit movement of the panes l and 2 relative to the frame, thu~ prevent fracturing in the case of mechanical stresq and in the case of differing thermal expansion of the frame portions and of the panes. The outer f~ame portions 5 and 6 and an intermediate frame portion 7 form a spacer which holds the panes l and 2 in ~paced parallel relationship. Films 8,9 are glued to the respective outer frame portion 5,6 but in an alternative construction , .
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~$1~ 3 ~, -16- t could be glued to the intermediate frame portion 7.
The mutually conrronting surfaces of the frame portions 5,6,7 are profiled such that they fit into one another.
The frame portions 5,6,7 are made from profiled bar 5 sections in conformity with the ~ize of the gla~s panes 1 and 2 and the lengths of the bar ~ection can be secured together by prefabricated corner piece~ (not shown). ~he frame portions 5,6,7 are interconnected by a plate 10 and screws 11. The~profiled surfaces of the 10 frame portions 5,6,7 are pressed against one another with the border regions of the films 8 and 9 sandwiched there-between so that the screws 11 are tightened 90 that the films 8,9 are stretched. The profiled surfaces of the frame portions 5,6,7 can be variously designed in a ~,~
suitable manner to obtain differing film tensions and thu~ differing resonance frequencies of the films 8,9.
If required, the interiors of the frame portions 5,6,7 can contain materials 12 which render possible further sound-proofing and thermal insulation of the individual frame portions a~d thus of the entire frame. Desiccants oan be provided on the inner surface of the frame portions 5,6,7 or the said frame portions can be provided with a silicone coating. An infrared-reflective coating i~
indicated on the films 8,9.
Importance has been attached to small installation dimensions in the embodiment illustrated in Fi~s.2, in which the space between the panes 1 and 2 i9 filled with ........ - . . . . .............. . .. ...... ..... . .......
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' t a gas which is denser than air in order to provide enhanced heat insulation. Here a ~ingle film 8 is in~erted between two frame portion~ 5,6 whose mutually confronting surfaces are profiled 80 as to stretch the film. ~he side~ of the frame portions 5,6 which are remote from the gas space are provided with surfaces 21,22 which are located parallel to one another and which are interconnected by a sealing material 23, so that the interior space between the panes l and 2 i9 sealed in an airtight manner. In this embodiment also, at least one of the frame portions 5 and 6 is provided with a de~iccant 13. Another frame 24 i8 provided around the edges of the panes l and 2 ~nd the outer edge of the frame. 3 The spacers 5,6,7 of ~ig.l and 5,6 of Fig.2 also conPtitute sealing means to prevent ingress of moisture into the space between the panes l and 2. The interior spaces of the embodiments of Figs. 3 and 4 on the other hand, are ventilated.
Identical parts in Figs. 3 and 4 are provided with the same reference numerals. The parts already described with reference to Figs. l and 2 will not be q described again in the case of~Figs. 3 and 4. Fig.3 shows a single film 8 stretched between frame portions 37 and 38 and ~ig.4 shows two films 8 and 9 stretched ~,~
between frame portions 37 and 38 and an intermediate fr~e por1 ion 42. i~

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~ he air space 35, located between the film 8 and the outer pane 2, communicates with the interior space of a profiled glazing strip 34 by way of an opening 32, an opening 33 and a sound-ab~orbent air filter 31 in the frame portion 37, the interior space of the glazing strip 34 in turn communicating with the outside atmosphere by way of a further opening 36. ~he filter 31 is made of spun-glass fabric and is impregnated to render it water-repellent and to enable it to act as a dust trap.
It is de~igned so as to permit the passage of only a ~mall quantity of air and 80 as~to transmit only a small amount of noise.
~ he glazing strip 34 is lined in the sound-absorbent material.
The double-glazing unit is fitted into a window ca~ement of, for example, 58 mm thickneQs. The inner pane l is laid again~t the base of a rabbet in an outer frame and the remaining width of the rabbet, i.e. the gap between the edge of the unit and the wall of the rabbet, is filled with a material 40 for thermal in~ulation purposes although admitting diffu~ion, a glued joint 43 between the inner pane and frame being ~ubstantially more moisture-proof than the filling material 40 which t ' extends approximately to the centre of the thickness of i~
the double-glazing unit (Fig.3) or to the plane of the room side of the outer air layer, i.e. the plane of the outer film 8 (Fig.4). ~he air flow in the profiled I .

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glazing ~trip 34 flow~ around the outer portion of the double-glazing unit, the profiled glazing strip being open at the bottom by way of the opening 36.
In the case of wooden windows, the region of the abutment of the unit again~t the rabbet bottom and of the thermal in~ulation needs only to be treated with a ventilation baqe in order to enable moisture exchange to take place between the air and the wood. The spacer constituted by the frame portions 37,38 or ~7,3~,40 i~ thu~ able to absorb and give off small quantitie~ of condensate. A plate 44 interconnects the two frame portions 37,38 and, in Fig.4, the inter-mediate frame portion 42 by, for example, screws 39 and ab~orb~ the force which ten~ion~ the film or films.
~he outer portion of the spacsr 37,38 or 37,38,40 is 80 constructed that it ~atisfactorily conduct~ or dissipates heat. A material having a large active ~urface or a large capillary ab~orption capacity can be provided on the inside of the spacer.
~he embodiment illustrated in Fig.4 corre~ponds to the embodiment illustrated in Fig.3, although measures are provided which take into account a thicker frame.
Iarger, heavier panes can be supported by the additional fitting of profiled section~ 41.
Fig. 5 is a plan view of a side edge closure having ventilation openings 45 in the glazing strip 46. The ventilation openings 45 are protected by interior ~' ~
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deflectors 47 to prevent ingreQ3 of rainwater. ~he openings 45 serve the same function as the opening~ -~6 in Fig~. 3 and 4.
~he films 8 and 9 can be correctly adhered to the frame portion~ 5 and 6 or 37 and 38 by putting adhesive on the frame portions and laying the film over the frame portionQ in contact with the adhe~ive.
A temporary outer frame (not shown) can be used to hold the film in place while it is adju~ted in position before the adheRive sets and until the adhe~ive has set.
~he frame portions 5,6,7 or 5,6 or 37,38 or 37,38,40 mutually support one another and al~o transfer the stress forces, arising due to the film tension, to the edge~ of the pane9 l,2.
A furthqr film can be applied, by means of an adhe~ive which does not transmit ultra-violet radiation, to the inside surface of the ou~er pane 2 facing the outermost film 8.
In the ca~e wherein several films are employed at lea~t one intermediate pane (not shown) can be provided ll between the films in order to-take up the ~tres~es arising due to the tension in the stretched films, thus providing a triple-glazing unit.
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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of stretching at least one film located between two panes comprising the steps of:
(a) providing at least two frame portions for forming a full frame, (b) providing said at least two frame portions with mutually confronting profiled surfaces, (c) securing each film to a respective frame portion, (d) assembling said at least two frame portions to form the full frame, and (e) pressing together said at least two frame portions to stretch the film by the coaction of the confronting profiled surfaces of adjacent frame portions.

2. A method as claimed in claim 1, comprising the further steps of:
(f) securing the film to at least one of said at least two frame portions by an adhesive, (g) slipping a peripheral frame onto said at least one of said at least two frame portions to hold the film in position before the adhesive sets, (h) correcting the position of the film, if necessary, and (i) then holding the film in this position until the adhesive sets.

3. A method as claimed in claim 1 in which the profiled surfaces are so formed as to predetermine the initial stress of the inserted film and thus to predetermine the resonance of the film.

4. A method as claimed in claim 1 further comprising securing a second film to another of said at least two frame portions and providing a further frame between said films to at least partially absorb the forces derived from the film tension.

5. A method as claimed in claim 1 in which the frame portions are each constructed as frames in accordance with the size of the panes.

6. A method as claimed in claim 1 in which the frame portions are constructed from prefabricated profiled bar sections.

7. A multiple glazing unit comprising:
(a) at least two panes, (b) a frame comprising at least two frame portions, (c) mutually confronting profiled surfaces on said at least two frame portions, and (d) at least one film, each of which is secured to a respective frame portion, so as to extend between and be substantially parallel to the panes and stretched between adjacent frame portions of said at least two frame portions upon the pulling action of the confronting profiled surfaces on said at least one film when assembling and pressing together said at least two frame portions.

8. A multiple glazing unit as claimed in claim 7 in which said at least one film has a coating which is reflective in the infrared range a said coating being sufficiently thin to protect against ultra-violet light discolouration.

9. A multiple glazing unit as claimed in claim 7 in which the inner surfaces of the panes and the surfaces of the at least one film are provided with a thin silicone coating.

10. A multiple glazing unit as claimed in claim 7 in which said at least two frame portions are made from a material which readily absorbs and gives off small quantities of condensate.

11. A multiple glazing unit as claimed in claim 7 in which at least some of said at least two frame portions constitute spacing and sealing means between the outer panes to hermetically seal the interior space between the panes.

12. A multiple glazing unit as claimed in claim 7 in which the interior space between the panes and/or between the panes and said at least one film, is filled with a gas to improve thermal insulation.

13. A multiple glazing unit as claimed in claim 7 in which at least some of said at least two frame portions constitute a spacer which is constructed to suppress vapour by providing a desiccant in the interior space thereof.

14. A multiple glazing unit as claimed in claim 7 in which at least some of said at least two frame portions constitute a spacer having an opening therein to diffuse vapour.

15. A multiple glazing unit as claimed in claim 7 in which at least some of said at least two frame portions constitute a spacer which is attached to the panes in a soundproofing manner.

16. A multiple glazing unit as claimed in claim 7 in which at least some of said at least two frame portions constitute a spacer to which a soundproofing material is applied.

17. A multiple glazing unit as claimed in claim 7 in which said at least two frame portions are constructed such that they mutually support one another and transmit the stress forces of said at least one film to the edges of the panes.

18. A multiple glazing unit as claimed in claim 7 in which a ventilated glazing strip is provided for ventilating at least a portion of the space between the panes.

19. A multiple glazing unit as claimed in claim 18 in which at least some of said at least two frame portions constitute a spacer whose outer portion satisfactorily conducts and/or dissipates heat.

20. A multiple glazing unit as claimed in claim 19 in which a material having a large active surface or a large capillary absorption capacity is provided on the inside of the spacer.

21. A multiple glazing unit as claimed in claim 7 further comprising an air filter disposed in said frame and by which the space between the outer pane and an adjacent film of said at least one film is ventilated.

22. A multiple glazing unit as claimed in claim 21 in which the air filter is impregnated to render it water-repellent and to enable it to trap dust.

23. A multiple glazing unit as claimed in claim 21 in which the air filter comprises spun glass fabric.

24. A multiple glazing unit as claimed in claim 21 in which the air filter permits the passage of only a small quantity of air and the transmission of only a small amount of sound.

25. A multiple glazing unit as claimed in claim 10 in which the inside of said at least two frame portions is lined with sound-absorbent material.

26. A multiple glazing unit as claimed in claim 7 in which a film is applied, by means of an adhesive which does not substantially transmit ultra-violet radiation, to the inside of that pane which, viewed from the outside, is situated in front of the outermost film.

27. A multiple glazing unit as claimed in claim 7 in which said profiled surfaces of adjacent frame portions of said at least two frame portions are matingly angled with respect to each other.