Low thermal conducting spacer assembly for an insulating glazing unit and method of making same
An insulating unit has a pair of glass sheets about an edge assembly to provide a compartment between the sheets. The edge assembly has a U-shaped spacer made of metal, metal coated plastic, gas and moisture impervious polymer, or gas and moisture impervious film coated polymer. The outer legs of the spacer and the glass provide a long diffusion path to limit the diffusion of argon gas out of the compartment. The edge assembly has materials selected and sized to provide edge assembly having an RES-value of at least 75. A spacer for use in insulating units includes a plastic core having a gas impervious film e.g. a metal film or a halogenated polymer film. Also taught herein are techniques for making the unit and spacer.
This is a division of U.S. patent application Ser. No. 09/789,377 filed Feb. 20, 2001, which is a division of U.S. patent application Ser. No. 08/760,605 filed Dec. 4, 1996, which is a division of U.S. patent application Ser. No. 08/412,028 filed Mar. 28, 1995, now U.S. Pat. No. 5,655,282, which is a file wrapper continuation of U.S. patent application Ser. No. 08/086,286 filed Jul. 1, 1993, now abandoned, which is a division of U.S. patent application Ser. No. 07/686,956 filed Apr. 18, 1991, now abandoned, which is a continuation-in-part application of U.S. patent application Ser. No. 07/578,696 filed on Sep. 4, 1990, in the names of Stephen C. Misera and William R. Siskos and entitled INSULATING GLAZING UNIT HAVING A LOW THERMAL CONDUCTING EDGE AND METHOD OF MAKING SAME, now abandoned.
The unit taught in this application may be fabricated using the spacer and spacer frame disclosed in U.S. patent application Ser. No. 07/578,697 filed on Sep. 4, 1990, in the names of Stephen C. Misera and William Siskos and entitled A SPACER AND SPACER FRAME FOR AN INSULATING GLAZING UNIT AND METHOD OF MAKING SAME.
BACKGROUND OF THE INVENTION1. Field of the Invention
This invention relates to an insulating glazing unit and a method of making same and, in particular, to an insulating glazing unit having an edge assembly to provide the unit with a low thermal conducting edge, i.e. high resistance to heat flow at the edge of the unit.
2. Discussion of Available Insulating Units
It is well recognized that insulating glazing units reduce heat transfer between the outside and inside of a home or other structures. A measure of insulating value generally used is the “U-value”. The U-value is the measure of heat in British Thermal Unit (BTU) passing through the unit per hour (Hr)-square foot (Sq.Ft.)-degree Fahrenheit (° F.)
As can be appreciated the lower the U-value the better the thermal insulating value of the unit, i.e. higher resistance to heat flow resulting in less heat conducted through the unit.
Another measure of insulating value is the “R-value” which is the inverse of the U-value. Still another measure is the resistance (RES) to heat flow which is stated in Hr-° F. per BTU per inch of perimeter of the unit
In the past the insulating property, e.g. U-value given for an insulating unit was the U-value measured at the center of the unit. Recently it has been recognized that the U-value of the edge of the unit must be considered separately to determine the overall thermal performance of the unit. For example, units that have a low center U-value and high edge U-value during the winter season exhibit no moisture condensation at the center of the unit, but may have condensation or even a thin line of ice at the edge of the unit near the frame. The condensation or ice at the edge of the unit indicates that there is heat loss through the unit and/or frame i.e. the edge has a high U-value. As can be appreciated, when the condensate or water from the melting ice runs down the unit onto wooden frames, the wood, if not properly cared for, will rot. Also, the larger temperature differences between the warm center and the cold edge can cause greater edge stress and glass breakage. The U-values of framed and unframed units and methods of determining same are discussed in more detail in the section entitled “Description of the Invention.”
Through the years, the design of and construction materials used to fabricate insulating glazing units, and the frames have improved to provide framed units having low U-values. Several types of units presently available, and center and edge U-values of selected ones, are considered in the following discussion.
Insulating glass edge units which are characterized by (1) the edges of the glass sheets welded together, (2) a low emissivity coating on one sheet and (3) argon in the space between the sheets are taught, among other places, in U.S. patent application Ser. No. 07/468,039 assigned to PPG Industries, Inc. filed on Jan. 22, 1990, in the names of P. J. Kovacik et al. and entitled “Method of and Apparatus for Joining Edges of Glass Sheets, One of Which Has an Electroconductive Coating and the Article Made Thereby.” The units taught therein have a measured center U-value of about 0.25 and a measured edge U-value of about 0.55. Although insulating units of this type are acceptable, there are limitations. For example, special equipment is required to heat and fuse the edges of the glass sheets together, and tempered glass is not used in the construction of the units.
In U.S. Pat. No. 4,807,439 there is taught an insulting unit marketed by PPG Industries, Inc. under the registered trademark SUNSEAL. The unit has a pair of glass sheets spaced about 0.45 inch (1.14 centimeters) apart about an organic edge assembly and air in the compartment between the sheets. A unit so constructed is expected to have a measured center U-value of about 0.35 and an edge U-value of about 0.59. Although providing insulating gas e.g. argon in the unit would lower the center and edge U-values, the argon in time would diffuse through the organic edge assembly raising the center and edge U-values to those values previously stated.
The unit of U.S. Pat. No. 4,831,799 has an organic edge assembly and a gas barrier coating, sheet or film at the peripheral edge of the unit to retain argon in the unit. The thermal performance of the unit is discussed in column 5 of the patent. U.S. Pat. Nos. 4,431,691 and 4,873,803 each teach a unit having a pair of glass sheets separated by an edge assembly having an organic bead having a thin rigid member embedded therein. Although the units of these patents have acceptable U-values, they have drawbacks. More particularly, the units have a short length, high resistance diffusion path. The diffusion path is the distance that gas, e.g. argon, air, or moisture has to travel to exit or enter the compartment between the sheets. The resistance of the diffusion path is determined by the permeability, thickness and length of the material. The units taught in U.S. Pat. Nos. 4,831,799; 4,431,691 and 4,873,803 have a high resistance, short diffusion path between the metal strip or spacing means and the glass sheets; the remainder of the edge assembly has a low resistance, long length diffusion path.
In U.S. Pat. No. 3,919,023, there is taught an edge assembly for an insulating unit that provides a high resistance, long length diffusion path that may be used to minimize the loss of argon. A limitation of the edge assembly of the patent is the use of a metal strip around the outer marginal edges of the unit. This metal strip conducts heat around the edge of the unit, and the unit is expected to have a high edge U-value.
It was mentioned that the effect of the frame U-value on the window edge U-value should be taken into account; however, a detailed discussion of frames having low U-value is omitted because the instant invention is directed to an insulating glazing unit that has low center and edge U-values, is easy to construct, does not have the limitations or drawbacks of the presently available insulating glazing units, and may be used with any frame construction.
SUMMARY OF THE INVENTIONThe invention covers an insulating unit having a pair of glass sheets separated by an edge assembly to provide a sealed compartment between the sheets having a gas therein. The edge assembly includes a spacer that is structurally sound to maintain the glass sheets in a fixed spaced relationship and yet accommodates a certain degree of thermal expansion and contraction which typically occurs in the several component parts of the insulating glazing unit. A diffusion path having resistance to the gas in the compartment e.g. a long thin diffusion path, is provided between the spacer and the glass sheets, and the edge assembly has a high RES value at the unit edge as determined using the ANSYS program.
The invention also covers a method of making an insulating unit. The method includes the steps of providing an edge assembly between a pair of glass sheets to provide a compartment therebetween. The edge assembly is fabricated by providing a pair of glass sheets; selecting a structurally resilient spacer, sealant materials and moisture pervious desiccant containing material to provide an edge assembly having a high RES as determined using the ANSYS program and a long thin diffusion path. The glass sheets, spacer, sealant material and desiccant containing materials are assembled to provide an insulating unit having a high RES at the edge as measured using the ANSYS program.
The preferred insulating unit of the invention has an environmental coating, e.g. a low-E coating on at least one sheet surface. Adhesive sealant on each of the outer surfaces of the spacer having a “U-shaped” cross section secures the sheets to the spacer. A strip of moisture pervious adhesive having a desiccant is provided on the inner surface of the spacer.
Further, the invention covers a spacer that may be used in the insulating unit. The spacer includes a structurally resilient core e.g. a plastic core having a moisture/gas impervious film e.g. a metal film or a halogenated polymeric film such as polyvinylidene chloride or flouride or polyvinyl chloride or polytrichlorofluoro ethylene.
Additionally, the spacer may be made entirely from a polymeric material having both structural resiliency and moisture/gas impervious characteristics such as a halogenated polymeric material including polyvinylidene chloride or flouride or polyvinyl chloride or polytrichlorofluoro ethylene.
BRIEF DESCRIPTION OF THE DRAWINGSFIGS. 1 thru 4 are cross sectional views of edge assemblies of prior art insulating units.
FIGS. 14 thru 16 are views taken along lines 14 thru 16 respectively of
In the following discussion like numerals refer to like elements, and the units are described having two glass sheets; however, as is appreciated by those skilled in the art, units with more than two sheets as shown in
With reference to
Unit 30 in
With reference to
In
Before teaching the construction of the insulating unit, more particularly the edge assembly of the instant invention, a discussion of the heat transfer through an insulated unit is deemed appropriate to fully appreciate the instant invention. In the following discussion the U-value will be used to compare or rate heat transfer i.e. resistance to heat flow through a glazing unit to reduce heat loss. As is appreciated by those skilled in the art the lower the U-value the less heat transfer and vice versa. The U-value for an insulating unit can be determined from the following equation.
Ut=(Ac/At)Uc+(Ae/At)Ue+(Af/At)Uf (1)
Where
U is the measure of heat transfer in British Thermal
Unit/hour-square foot-° F. (BTU/Hr-Sq.Ft.-° F.)
A is area under consideration in square feet
c designates the center of the unit
e designates the edge of the unit
f designates the frame
t is total unit value of the parameter under discussion
Shown in
The left half of unit 90 shown in
The heat flow through the center area 96 of the unit 90 may be modified by changes in the thermal properties of sheets 12 and 14, the distance between the sheets and gas in the compartment 18. Consider now the distance between the sheets i.e. the compartment spacing. Compartments having a spacing between about 0.250-0.500 inch (0.63-1.27 centimeters) are considered acceptable to provide an insulating gas layer with the preferred spacing depending on the insulating gases used. Krypton gas is preferred at the low range, air and argon are preferred at the upper range. In general, below 0.250 inch (0.63 centimeter) the spacing is not wide enough e.g. for air or argon gas to provide a significant insulating gas layer and above 0.500 inch (1.27 centimeters), gas currents e.g. using krypton gas in the compartment have sufficient mobility to allow convection thereby moving heat between the glass surfaces, e.g. between the glass surface facing the house interior to the glass surface facing the house exterior.
As previously mentioned, heat flow through the unit may also be modified by the type of gas used in the compartment. For example, using a gas that has a high thermal insulating value increases the performance of the unit, in other words it decreases the U-value at the center and edge areas of the unit. By way of example, but not limiting to the invention, argon has a higher thermal insulating value than air. Everything else relating to the construction of the unit being equal, using argon would lower the U-value of the unit.
Another technique to modify the thermal insulating value of the center area is to use sheets having high thermal insulating values and/or sheets having low emissivity coatings, for example coating 105 as shown in
The discussion will now be directed to the thermal loss at the edge area of the unit. With reference to
As can be seen in
The heat loss for an edge assembly using a metal spacer, in particular an aluminum spacer is greater than for glass because the aluminum spacer has a higher thermal conductivity (aluminum is a better conductor of heat than glass or organic materials). The effect of the higher thermal conductivity of the aluminum spacer is also evident at point D which shows the curve 120 for the aluminum spacer to have a higher temperature than the curve 140 or the curve 130 at the outside surface of the unit. The heat to maintain the higher temperature at D for the aluminum spacer is conducted from inside the house thereby resulting in a heat loss at the edge of the unit greater than the edge heat loss for units having glass or organic spacers, and greater than the edge assembly of the invention as will be discussed in detail below.
The heat loss for an edge assembly having an organic spacer is less than the heat loss for edge assemblies having metal spacers or welded glass because the organic spacer has a lower thermal conductivity. The effect of the lower thermal conductivity of the organic spacer is shown by line 130 at point D which has a lower temperature than the glass and metal spacers illustrating that conductive heat loss through the organic spacer is less than for glass and metal spacers.
A phenomenon of units having high edge heat loss is that on very cold days, a thin layer of condensation or ice forms at the inside of the unit at the frame. This ice or condensate may be present even though the center of the unit is free of moisture.
As was discussed, units that have argon in the compartment and polymeric edge assemblies may have an initial low U-value, but as time passes, the U-value increases because polymeric spacers as a general rule do not retain argon. To retain argon an additional film such as that taught in U.S. Pat. No. 4,831,799 is required. The drawback of the unit of this U.S. Pat. No. 4,831,799 is that the film has a short diffusion path as was discussed supra. As can be appreciated argon retention can be improved by selection of materials e.g. hot melt adhesive sealants such as HB Fuller 1191, HB Fuller 1081A and PPG Industries, Inc. 4442 butyl sealant retain argon better than most polyurethane adhesives.
With reference to
With respect to the ingress of moisture into the unit, the geometry of the sealant bead is chosen so that the amount of moisture permeating through the perimeter parts (i.e. sealant bead and spacer) is a quantity able to be absorbed into the quantity of desiccant within the unit over the desired unit lifetime. The preferred adhesive sealant to be used with the spacer of
The relationship between the amount of desiccant in the unit and the permeability of the sealant (and its geometry) may be varied depending on the overall desired unit lifetime.
An additional adhesive sealant type layer or structural adhesive layer 155 e.g. but not limited to silicone adhesive and/or hot melts may be provided in the perimeter groove of the unit formed by middle leg 157 of the spacer and marginal edges of the glass sheets. As can now be appreciated the sealant is not limiting to the invention and may be any of the types known in the art e.g. the type taught in U.S. Pat. No. 4,109,431 which teachings are hereby incorporated by reference. A thin layer 160 of a moisture pervious adhesive having a desiccant 162 therein to absorb moisture in the compartment 18 is provided on the inner surface of the middle leg 157 of the spacer 158 as viewed in
To fully appreciate the high resistance to heat loss of the edge assembly of the instant invention, the following discussion of the mechanism of thermal conductivity through the edge of an insulated unit is presented.
The heat loss through an edge of a unit is a function of the thermal conductivity of the materials used, their physical arrangement, the thermal conductivity of the frame and surface film coefficient. Surface film coefficient is transfer of heat from air to glass at the warm side of the unit and heat transfer from glass to air on the cold side of the unit. The surface film coefficient depends on the weather and the environment. Since the weather and environment are controlled by nature and not by unit design, no further discussion is deemed necessary. The frame effect will be discussed later leaving the present discussion to the thermal conductivity of the materials at the unit edge and their physical arrangement.
The resistance of the edge of the unit to heat loss for an insulating unit having sheet material separated by an edge assembly is given by equation (2).
RHL=G1+G2+ . . . +Gn+S1+S2+ . . . +Sn (2)
where
RHL is the resistance to edge heat loss at the edge of the unit in hour-° F./BTU/inch of unit perimeter (Hr-° F./BTU/in.)
G is the resistance to heat loss of a sheet in Hr-° F./BTU/in.
S is the resistance to heat loss of the edge assembly in Hr-° F./BTU/in.
For an insulating unit having two sheets separated by a single edge assembly equation (2) may be rewritten as equation (3).
RHL=G1+G2+S1 (3)
The thermal resistance of a material is given by equation (4).
R=L/KA (4)
where
R is the thermal resistance in Hr-° F./BTU/in.
K is thermal conductivity of the material in BTU/hour-inch-° F.
L is the thickness of the material as measured in inches along an axis parallel to the heat flow.
A is the area of the material as measured in square inches along an axis transverse to the heat flow/in. of perimeter.
The thermal resistance for components of an edge assembly that lie in a line substantially perpendicular or normal to the major surface of the unit is determined by equation (5).
S=R1+R2+ . . . +Rn (5)
where S and R are as previously defined.
In those instances where the components of an edge assembly lie along an axis parallel to the major surface of the unit, the thermal resistance (S) is defined by the following equation (6).
where R is as previously defined.
Combining equations (3), (5) and (6) the resistance of the edge of the unit 150 shown in
where
RHL is as previously defined,
R12 and R14 are the thermal resistance of the glass sheets,
R154 is the thermal resistance of the adhesive layer 154,
R155 is the thermal resistance of the adhesive layer 155,
R156 is the thermal resistance of the outer legs 156 of the spacer 158,
R157 is the thermal resistance of the middle leg 157 of the spacer 158, and
R160 is the thermal resistance of the adhesive layer 160.
Although equation (7) shows the relation of the components to determine edge resistance to heat loss, Equation 7 is an approximate method used in standard engineering calculations. Computer programs are available which solve the exact relations governing heat flow or resistance to heat flow through the edge of the unit.
One computer program that is available is the thermal analysis package of the ANSYS program available from Swanson Analysis Systems Inc. of Houston, Pa. The ANSYS program was used to determine the resistance to edge heat loss or U-value for units similar to those shown in
The edge U-value, defined previously, while being a measure of the overall effect demonstrating the utility of the invention is highly dependent on certain phenomena that are not limiting to the invention such as film coefficients, glass thickness and frame construction. The discussion of the edge resistance of the edge assembly (excluding the glass sheets) will now be considered. The edge resistance of the edge assembly is defined by the inverse of the flow of heat that occurs from the interface of the glass and sealant layer 154 at the inside side of the unit to the interface of glass and sealant layer 154 at the outside side of the unit per unit increment of temperature, per unit length of edge assembly perimeter. The glass sealant interfaces are assumed to be isothermal to simplify the discussion. Support for the above position may be found, among other places, in the paper entitled Thermal Resistance Measurements of Glazing System Edge-Seals and Seal Materials Using a Guarded Heater Plate Apparatus written by J. L. Wright and H. F. Sullivan ASHRAE TRANSACTIONS 1989, V. 95, Pt. 2.
In the following discussion and in the claims, a parameter of interest is the resistance to heat flow of the edge assembly per unit length of perimeter (“RES”).
As mentioned above, the ANSYS finite element code was used to determine the RES. The result of the ANSYS calculation is dependent on the assumed geometry of the cross section of the edge assembly and the assumed thermal conductivity of the constituents thereof. The geometry of any such cross section can easily be measured by studying the unit edge assembly. The thermal conductivity of the constituents or the edge assembly RES value can be measured as shown in ASHRAE TRANSACTIONS identified above. The following thermal conductivity values for edge assembly materials are given in the article. Additional values may be found in Principles of Heat Transfer 3rd ed. by Frank Kreith.
Let us now consider the RES calculated for edge assemblies of the units of
The construction of the edge assembly 32 of the unit 30 of
The construction of the edge assembly 52 of the unit 50 of
A unit similar to the unit 50 of
The construction of the edge assembly of the unit 70 of
The construction of the edge assembly 150 of the instant invention shown in
Shown in
If a material other than polyvinylidene chloride is used as the barrier film, the proper thickness to retain the fill gas for the desired unit lifetime may be adjusted depending on the material's gas containment characteristics.
The fill gas retention characteristics of the unit according to the instant invention is measured by the above referred DIN 52293.
For argon, the film 165 may be a 0.0001 inch (0.000254 centimeter) thick aluminum film or a 0.005 inch thick film of polyvinylidene chloride. As used herein the argon impervious material has a permeability to argon of less than 5%/yr. The invention contemplates having a core 164 and a thin layer of film 165 or several layers 164 and 165 to build up a laminated structure. Using the spacer 163 having the aluminum film in place of the spacer 155 of the unit 150 in
The instant invention also contemplates having a spacer 163 of
The spacer of the instant invention, in addition to acting as a barrier to the insulating gas in the compartment 18, is structurally sound. As used herein and in the claims “structurally sound” means the spacer maintains the glass sheets in a spaced relationship while permitting local flexure of the glass due to changes in barometric pressure, temperature and wind load. The feature of maintaining the glass sheets in a fixed spacer relationship means that the spacer prevents the glass sheets from significantly moving toward one another when the edges of the unit are secured in the glazing frame. As can be appreciated less force is applied to the edges of residential units mounted in a wooden frame than to edges of commercial units mounted by pressure glazing in metal curtainwall systems. Permitting local flexure means the spacer allows rotation of the marginal edge portions of the glass about its edge during loading of the types described while restricting movement other than rotation i.e. translation. The degree of structural soundness is related to type of material and thickness. For example metal may be thin where plastic to have the same structural soundness must be thicker or reinforced e.g. by fiber glass.
Embodiments of the instant invention may be used to improve the performance of the prior art units. For example replacing the spacer of the unit 10 of
The unit 150 of the instant invention having the spacer assembly 152 shown in
In actual tests a unit having an edge assembly of the instant invention and a unit having the edge assembly shown in
As was discussed the teachings of the invention may be used to increase edge assembly RES-value of a unit by using the spacer shown in
As can now be appreciated the unit of the instant invention provides an edge assembly having a metal spacer, a metal coated plastic spacer or a plastic spacer or a multi-layered plastic spacer that retain insulating gas other than air, e.g. argon, has a relatively high edge assembly RES-value or low U-value and has structural soundness.
The discussion will now be directed to the U-value of the frame of the unit. The frame also conducts heat and in certain instances e.g. metal frames conduct sufficiently more heat than the edge assembly of the unit such that the edge heat loss through the frame overshadows any increase in thermal resistance to heat loss provided at the edge of the unit. Wooden frames, metal frames with thermal breaks or plastic frames have high resistance to heat loss and the performance of the edge heat loss of the unit would be more dominant.
The invention is not limited to units having two sheets but may be practiced to make units having two or more sheets e.g. unit 250 shown in
The discussion will now be directed to a method of fabricating the glazing unit of the instant invention. As will be appreciated the unit of the instant invention may be fabricated in any manner; however, the construction of the unit is discussed using selected ones of the edge assembly components taught in U.S. patent application Ser. No. 07/578,697 filed Sep. 4, 1990, in the names of Stephen C. Misera and William R. Siskos and entitled A SPACER AND SPACER FRAME FOR AN INSULATING GLAZING UNIT AND METHOD OF MAKING SAME which teachings are hereby incorporated by reference.
With reference to
As can be appreciated the desiccant bead may be any type of adhesive or polymeric material that is moisture pervious and can be mixed with a desiccant. In this manner the desiccant can be contained in the adhesive or polymer material and secured to the substrate while having communication to the compartment. Types of materials that are recommended, but the invention is not limited thereto, are polyurethanes and silicones. Further the bead may be the spacer dehydrator element taught in U.S. Pat. No. 3,919,023 which teachings are hereby incorporated by reference.
Further, as can now be appreciated one or both sides of one or more sheets may have an environmental coating such as the one taught in U.S. Pat. Nos. 4,610,771; 4,806,220; 4,853,256; 4,170,460; 4,239,816 and 4,719,127 which patents are hereby incorporated by reference.
In the practice of the invention the metal substrate after forming into spacer stock and the bead has sufficient structural strength and resiliency to keep the sheets spaced apart and yet accommodates a certain degree of thermal expansion and contraction which typically occurs in the several component parts of the insulating glazing unit. In one embodiment of the invention the spacer is more structurally stable than the bead i.e. the spacer is sufficiently structurally stable or dimensionally stable to maintain the sheets spaced from one another whereas the bead cannot. In another embodiment of the invention both the spacer and the bead can. For example, the bead may be a desiccant in a preferred spacer taught in U.S. Pat. No. 3,919,023 to Bowser. As can be appreciated by those skilled in the art, a metal spacer can be fabricated through a series of bends and shaped to withstand various compressive forces. The invention relating to the bead 160 carried on the substrate 170 is defined by shaping the substrate 170 into a single walled U-shaped spacer stock with the resultant U-shaped spacer stock being capable of withstanding values of compressive force to maintain the sheets apart regardless of the structural stability of the bead. As can be appreciated by those skilled in the art the measure and value of compressive forces and structural stability varies depending on the use of the unit. For example if the unit is secured in position by clamping the edges of the unit such as in curtainwall systems, the spacer has to have sufficient strength to maintain the glass sheet apart while under compressive forces of the clamping action. When the use is mounted in a rabbit of a wooden frame and caulking applied to seal the unit in place, the spacer does need as much structural stability to maintain the glass sheets apart as does a spacer of a unit that is clamped in position.
The edges of the strip 150 are bent in any convenient manner to form outer legs 156 of a spacer 158 shown in
With reference to
With reference to
As can now be appreciated the grooves of the upper roll forming wheels may be shaped to shape the bead of material on the substrate.
In the practice of the invention the bead 160 was applied after the spacer stock was formed e.g. the substrate formed into a U-shaped spacer stock. This was accomplished by pulling the substrate through a die of the type known in the art to form a flat strip into a U-shaped strip.
As can be appreciated, everything else being equal, loose desiccant is a better thermal insulation than desiccant in a moisture pervious material. However, handling and containing loose desiccant in a spacer in certain instances is more of a limitation than handling desiccant in a moisture pervious matrix. Further having the desiccant in a moisture pervious matrix increases the shelf life because the desiccant takes a longer period of time to become saturated when in a moisture and/or gas pervious material as compared to being directly exposed to moisture. The length of time depends on the porosity of the material. However, the invention contemplates both the use of loose desiccant and desiccant in a moisture pervious matrix.
The spacer stock 158 may be formed into a spacer frame for positioning between the sheets. As can be appreciated, the layers 154 and 155, shown in
With reference to
With reference to
A layer 155 of an adhesive if not previously provided on the frame is provided in the peripheral channel of the unit (see
As can be appreciated by those skilled in the art, the invention is not limited by the above discussion which was presented for illustrative purposes only.
Claims
1. A spacer stock used for fabricating a spacer frame for an insulating unit, the insulating unit having a pair of sheets maintained in spaced relationship by the spacer frame and an insulating gas between the glass sheets, the spacer stock comprising:
- a structurally sound elongated plastic member comprising a first end, an opposite second end, a base continuous from the first end to the second end with outer surface of the base lying in a first plane, a first leg having an outer major surface and an opposite inner major surface with the outer surface of the first leg lying in a second plane normal to the first plane, and a second leg having an outer major surface and an opposite inner major surface with the outer surface of the second leg lying in a third plane normal to the first plane, the inner surface first and second legs spaced from one another and the first and second legs interconnected to one another only through the base such that the first and second legs and the base have a generally U-shaped cross section, a first V-shaped bending line in at least one of the surfaces of the first leg and lying in the second plane, and a second V-shaped bending line in at least one of the surfaces of the second leg and lying in the third plane with open end of the first and second V-shaped bending lines space a greater distance from the base than the closed end of the first and second V-shaped bending lines.
2. The spacer stock according to claim 1 wherein the outer surfaces of the base, the first leg and the second leg provide outer surface of the plastic member, and the inner surfaces of the first leg and the second leg and surface of the base between the inner surfaces of the first and second legs provide inner surface of the plastic member, and at least one of the inner and outer surfaces of the plastic member is a moisture and gas impervious surface.
3. The spacer stock according to claim 2 wherein the plastic member is made of a halogenated polymeric material.
4. The spacer stock according to claim 2 wherein the plastic member is a laminated plastic member comprising a structurally sound polymeric core and a moisture and gas impervious film secured to the plastic core wherein the film provides the laminated plastic member with the moisture and gas impervious surface.
5. The spacer stock according to claim 4 further comprising a bead of a moisture pervious adhesive matrix having a desiccant mixed therein, the bead secured to the surface of the base between the first and second legs.
6. The spacer stock according to claim 4 wherein the polymeric core is a fiberglass reinforced polymeric core.
7. The spacer stock according to claim 1 wherein the first and second V-shaped bending lines are imposed in but do not extend through their respective leg.
8. The spacer stock according to claim 1 wherein the first and second V-shaped bending lines are imposed in their respective leg with the bending lines imposed at the closed end of the first and second V-shaped bending lines not extending through their respective leg and indentations imposed at the open end of the first and second V-shaped lines extending through their respective leg to provide a material void at the open end of each of the first and second V-shaped bending lines.
9. The spacer stock according to claim 1 further comprising a moisture and gas impervious metal film on the outer surface of each of the first and second legs and the outer surface of the base, or on the inner surface of each of the first and second legs and surface of the base between thje first and second legs.
10. The spacer stock according to claim 1 wherein the structurally sound elongated plastic member is a structurally sound moisture and gas impervious plastic member and further comprising a bead of a moisture pervious adhesive matrix having a desiccant mixed therein secured on surface of the base beween the first and second legs.
11. In an insulating unit having a closed spacer frame, the spacer frame comprising an outer peripheral surface, a first side and an opposite second side, the spacer frame between a pair of sheets with one of the sheets secured to outer surface of the first side of the spacer frame by a first layer of a moisture impervious sealant and with the other one of the sheets secured to outer surface of the second side of the spacer frame by a second layer of a moisture impervious adhesive to provide a compartment between the sheets, the improvement comprising:
- the spacer frame made of a moisture and gas impervious material and comprises at least three corners with the spacer frame between adjacent corners having a generally U-shaped cross-sectional configuration having the first side of the frame extending from a base and the second side of the frame extending from the base, the first and second sides spaced from one another and only connected by the base, portion of outer surface of the base on one side of one of the corners defined as a first corner extends away from the first corner and lies in a first plane, portion of the outer surface of the base on other side of the first corner extends away from the first corner and lies in a second plane with the first and second planes intersecting on another at the first corner of the frame, the outer surface of the first side of the frame lies in a the third plane normal to the first and second planes and the outer surface of the second side of the frame lies in a fourth plane parallel to the third plane and normal to the first and second planes wherein portions of the first and second sides of the frame at the first corner of the frame extend toward one another over inner surface of the base, and
- a bead of a moisture pervious matrix having a desiccant mixed therein between the first and second sides of the frame on selected surface portions of the base.
12. The insulating unit according to claim 11 wherein the bead has a structural stability to maintain the sheets spaced from one another less than the structural stability of the spacer frame to maintain the sheets spaced from one another.
13. The insulating unit according to claim 12 wherein the spacer frame is made of moisture and gas impervious plastic.
14. The insulating unit according to claim 12 wherein the spacer frame is made of metal.
15. The insulating unit according to claim 12 wherein the portions of the first and second sides extending toward one another over the base are spaced from one another.
16. The improved insulating unit according to claim 12 wherein the spacer frame is made of one piece of a moisture and gas impervious material and having four sides and four corners, the base having a seamless portion starting at a first position adjacent to and spaced from a first corner and a path extend from first position over the first corner, over the next adjacent corner defined as the second corner, over the next adjacent corner defined as the third corner and ending at a position between the third and fourth corners,
17. The insulating unit according to claim 16 wherein the spacer frame at each of the first, second and third corners has a pair of creases imposed in outer surface of the first and second sides of the spacer frame, each of the pair of the creases extending away from the base with the distance between the creases increasing as the distance from the base increases to provide the two creases with a “V” shape and portions of the sides between the “V” shape at the one of the corners are the portions of the first and second sides that extend toward one another over the base.
18. The insulating unit according to claim 17 wherein a portion of the outer leg in the “V” shape between the creases is removed.
19. The insulating unit according to claim 11 further comprising an insulating gas in the compartment and wherein
- the spacer frame is a laminated spacer frame comprising (1) a structurally stable plastic core having a generally U-shaped cross-sectional configuration having a first outer leg having an outer major surface and an inner major surface, a second outer leg having an outer major surface and inner major surface and a base having an outer major surface and an inner major surface and a moisture and gas impervious film secured to at least one of the following groups (A) the inner major surface of the first leg, the inner major surface of the second leg and the inner major surface of the base and (B) the outer major surface of the first leg, the outer major surface of the second leg and the outer major surface of the base to substantially prevent the movement of moisture and gas between the compartment and atmosphere outside the compartment through the plastic core, (2) four sides and four corners, (3) a continuous base extending around the first corner, adjacent corner defined as the second corner and around the next adjacent corner defined as the third corner of the spacer frame, (4) each of the first and second sides of the spacer frame at the first corner have creases extending away from the base with spaced distance between the creases increasing as the distance from the base increases to provide a generally V shape crease with second portions of the first and second sides between its respective V shaped crease extending toward one another over inner surface of the base;
- the bead having a structural stability to maintain the sheets spaced from one another less than the structural stability of the laminated spacer frame to maintain the sheets spaced from one another, and
- the first and second layers of the moisture impervious sealant each have a thickness less than 0.020 inch (0.0508 centimeter) and a length at least 0.125 inch (0.32 centimeter) long that forms a barrier that resists loss of the insulating gas from the compartment.
20. The insulating unit according to claim 19 wherein the moisture and gas impervious film is on the outer major surface of the first leg, the outer major surface of the second leg and the outer major surface of the base of the plastic core wherein the moisture and gas impervious film provide the outer surface of the first and second sides of the spacer frame.
21. The insulating unit according to claim 20 wherein the moisture and gas impervious film is a moisture and gas impervious plastic film.
22. The insulating unit according to claim 21 wherein the plastic core is a fiberglass reinforced plastic core, and the film is a halogenated polymeric material.
23. The insulating unit according to claim 21
- wherein the spacer frame has four sides with the first side lying in the first plane, the second side lying in the second plane normal to the first plane, the third side lying in a fifth plane normal to the second plane and parallel to the first plane and the fourth side lying in a sixth plane normal to the fifth plane and the first plane and parallel to the second plane, the base of the spacer frame is a continuous base extending around the first corner, the intersection of the second plane and the fifth plane defined as a second corner of the spacer frame, and the intersection of the fifth plane and the sixth plane defined as the third corner of the spacer frame, and
- the spacer frame further comprising a structurally stable plastic core having a generally U-shaped cross-sectional configuration and a moisture and gas impervious metal film completely covering outer major surface of the plastic core to substantially prevent the movement of moisture and gas between the compartment and atmosphere outside the compartment through the plastic core.
24. In an insulating unit having a pair of sheets separated by a spacer frame, the spacer frame having a pair of opposed outer major surfaces with a first moisture impervious adhesive layer securing one of the opposed outer major surfaces of the spacer frame to portions of inner major surface of one of the pair of sheets and a second moisture impervious adhesive layer securing the other one of the opposed outer major surfaces of the spacer frame to portions of inner major surface of the other one of the pair of sheets to provide a compartment between the pair of sheets, the improvement comprising:
- the spacer frame is a laminated closed ended spacer frame comprising a base and a pair of outer legs spaced from one another and are only interconnected by the base to provide the spacer frame with a generally U-shaped cross-sectional configuration, and a first member and a second member wherein the first member is a structurally stable plastic core having a generally U-shaped cross-sectional configuration, an outer surface area and an opposite inner surface area, and the second member is a moisture and gas impervious film secured to and completely covering all of the surface area of at least one of the inner and outer surface areas of the plastic core to substantially prevent movement of moisture through the plastic core, the outer surface of one of the legs of the laminated spacer frame is adhered to one of the sheets by the first moisture impervious adhesive layer and outer surface of other one of the legs of the laminated spacer frame is adhered to the other one of the sheets by the second moisture impervious adhesive layer, and
- a bead of a moisture pervious adhesive matrix having a desiccant mixed therein on selected portions of inner surface of the base of the spacer frame.
25. The insulating unit according to claim 25 wherein the bead on the selected portions of the base has a structural stability to maintain the sheets spaced from one another less than the structural stability of the spacer frame to maintain the sheets spaced from one another.
26. The insulating unit according to claim 24 wherein the plastic core is a moisture and gas pervious plastic core.
27. The insulating unit according to claim 24 wherein the moisture and gas impervious film is secured to and completely covers the outer surface area of the plastic core, the first moisture impervious adhesive layer secures outer surface portions of the moisture and gas impervious film to the portions of the inner major surface of the one of the pair of sheets and the second moisture impervious adhesive layer secures outer surface portions of the moisture and gas impervious film to the portions of the inner major surface of the other one of the pair of sheets.
28. The insulating unit according to claim 27 wherein the spacer frame has four corners with portions of the first leg of the spacer frame between adjacent corners of the spacer frame having the outer surface of the first leg lying in a first plane and portions of the second leg of the spacer frame between adjacent corners of the spacer frame having the outer surface of the second leg lying in a second plane substantially parallel to the first plane wherein remaining portions of the first leg of the spacer frame at each of three corner of the spacer frame extending away from the first plane over the base toward the second plane, and remaining portion of the second leg of the spacer frame at each of three corners of the spacer frame extending away from the second plane over the base toward the first plane.
29. The insulating unit according to claim 28 wherein the remaining portions of the first and second legs extending over the base at each of the three corners of the spacer frame are spaced from one another.
30. The insulating unit according to claim 27 wherein the sheets are glass sheets; at least one glass sheet has an environmental coating, the plastic core is a fiber glass reinforced moisture and gas pervious plastic core, and the film is a halogenated polymeric material, and further comprising a moisture impervious sealant between the edges of the pair of glass sheets and on surface portions of the moisture impervious film facing away from the compartment.
31. In an insulating unit having a spacer frame between, and secured by a moisture impervious sealant to a pair of sheets to provide a compartment between the sheets, the improvement comprising:
- the spacer frame comprising four sides, four corners, a structurally stable U-shaped plastic core having a first outer leg and a second outer leg, the first and second outer legs spaced from one another and connected to a base, a moisture and gas impervious film secured to outer major surface of the first leg, the second leg and the base to provide a laminated spacer frame, the base and the first and second outer legs are each continuous from a first position adjacent to and spaced from a first corner around the first corner, around adjacent next corner defined as the second corner, around next adjacent corner defined as the third corner and terminating at a position spaced from the third corner, portions of the first outer leg between the corners providing a first sheet supporting surface and portions of the second outer leg between the corners providing a second sheet supporting surface, the outer legs connected only by the base and portions of the first leg and portions of the second leg at the first, second and third corners extending toward one another over the base of the spacer frame;
- the moisture impervious sealant comprising a first moisture impervious adhesive layer on outer surface of the first sheet supporting surface to secure the first sheet supporting surface and adjacent major surface portion of one of the pair of sheets to one another and a second moisture impervious adhesive layer on outer surface of the second sheet supporting surface to secure the second sheet supporting surface and adjacent major surface portion of other one of the pair of sheets to one another, and
- a bead of a moisture pervious matrix having a desiccant mixed therein on selected portions of inner surface of the base.
32. The insulating unit according to claim 31 wherein the core is made of plastic.
33. The insulating unit according to claim 32 wherein the film is a moisture and gas impervious plastic film.
34. The insulating unit according to claim 31 wherein the film is a moisture and gas impervious metal film.
35. The insulating unit according to claim 31 further comprising a moisture impervious sealant on outer surface of the base of the spacer frame.
36. A strip for use in the fabrication of a spacer frame used in the fabrication of an insulating unit wherein the spacer frame has a perimeter having a predetermined length; a first leg extending upward from a base; a second leg spaced from the first leg and extending upward from the base; the base having a predetermined width as measured between the first and second legs; the first and second legs each having a predetermined height as measured from surface of the base between the legs, and the first and second legs and the base forming generally U-shaped cross section, the strip comprising:
- a contiguous elongated flat bendable plastic substrate having opposed major surfaces, at least one of the major surfaces of the substrate being fluid impervious, the substrate having a predetermined length equal to or greater than the predetermined length of the spacer frame and a width equal to or greater than the sum of the predetermined height of the first and second legs and the predetermined width of the base, and
- an elongated bead of a fluid pervious adhesive having a desiccant mixed therein with the bead adhered directly to one of the major surfaces of the plastic substrate spaced from edges of the substrate, wherein the height of the bead as measured from the major surface of the plastic substrate is less than predetermined height of the first leg, and the adhesive has structural stability less than the structural stability of the substrate.
37. The strip according to claim 36 wherein the substrate is made of a halogenated polymeric material.
38. The strip according to claim 37 wherein the halogenated polymeric material is selected from the group of polyvinylidene chloride, polyvinylidene fluoride, polyvinyl chloride and polytrichlorofluoro ethylene.
39. The strip according to claim 36 wherein the adhesive is a polyurethane adhesive.
40. The strip according to claim 36 wherein the adhesive is a silicone adhesive.
41. The strip according to claim 36 wherein the major face of the substrate is a first major surface of the substrate and the substrate further comprises an opposite second major surface; the substrate is a laminated substrate comprising major surface of a first film secured to major surface of a second film with outer major surface of the first film providing the first major surface of the substrate and outer major surface of the second film providing the second major surface of the substrate, wherein the first film is a moisture pervious plastic film and the second film is a moisture impervious film.
42. The strip according to claim 41 wherein the second film is selected from the group of metal films and fluid impervious plastic films.
43. The strip according to claim 41 wherein at least one of the major surfaces of the substrate has depressions having a generally V-shape configuration with the opening of the V adjacent the edges of the substrate to indicate bending position of the spacer stock.
44. The strip according to claim 43 wherein portion of the substrate between at least one of the V-shaped depressions is removed to provide an open area between the at least one of the V-shaped depressions.
Type: Application
Filed: Feb 15, 2006
Publication Date: Jun 22, 2006
Inventors: Robert Hodek (Gibsonia, PA), Thomas Kerr (Pittsburgh, PA), Stephen Misera (Tarentum, PA), William Siskos (Salem Township, PA), Albert Thompson (Allegheny Township, PA)
Application Number: 11/355,037
International Classification: E04C 2/54 (20060101);