WO2019097537A1

WO2019097537A1 - Igu pressure equalizer

Info

Publication number: WO2019097537A1
Application number: PCT/IN2018/050705
Authority: WO
Inventors: Mohammed Ashik V A; Shankar Ganesh RAJI; Muthukaruppan V
Original assignee: Saint-Gobain Glass France
Priority date: 2017-11-15
Filing date: 2018-10-31
Publication date: 2019-05-23

Abstract

An insulating glazing unit (IGU) pressure equalizer for equalizing pressure in an enclosed space (430) of the IGU (400) is disclosed. The IGU pressure equalizer comprises of a corner key (100) and a corner plug (200) firmly cast into the corner key (100). A capillary-like recess (240) provided in the corner plug (200) together with an aperture (130) provided in the corner key (100) allows for passage of air between the enclosed space (430) between the two opposing glazing panels (410, 420) of the IGU (400) and the external environment. Further a method (500) for equalization of pressure in an IGU (400) is also disclosed.

Description

IGU PRESSURE EQUALIZER

Technical Field

The present disclosure relates, in general to an insulating glazing unit (IGU), and more specifically to an IGU provided with a pressure equalizer for equalizing pressure within an enclosed space provided therebetween two opposing glazing panels of the IGU and a method for equalization of pressure in an IGU.

Background

Over the past few decades, the use of glazing on our high-rise buildings has increased dramatically. More recently, as a result of increased industry recognition of the importance of energy efficiency, the trend is towards more energy-efficient glazing systems. Common methods of improving thermal performance of insulating glass units (IGUs) include the application of high- performance coatings, use of triple glazing or warm-edge-spacer technology, and installation of solar-selective films on or inside the units. While these solutions have all been effective at improving thermal performance, there have been cases where the implementation of this new technology has resulted in premature and costly failures.

Some of the common symptoms indicating IGU failure are found to be condensation within the sealed unit, corrosion of the low-emissivity (low-e) surface films, deflection of the edge spacer, and volatile fogging. Each symptom shows where the IGU design or manufacturing issues introduced failure mechanisms. In most cases, a failed IGU will require extensive costly work to remove and replace.

Capillary tubes and breather tubes are commonly used in IGU to equalize the pressure between the sealed panes. The main reason for the use of capillary or breather tubes is for installation of windows at high altitudes. When a sealed IGU is constructed at low altitudes and then installed at higher altitudes the resulting increase in altitude causes the glass panes to bow out, having a pillow shape appearance. The glass bows out because the sealed pressure at the time of assembly is greater than the pressure incurred at the higher elevation. If the pressure change is large, the insulating glass panes can fracture and/or the sealant holding the glass panes can rupture causing premature seal failure. Even when the IGUs are installed at the same elevation where they were made, if they were shipped over a high-elevation pass the glass could break or the seals could fail en route.

When temperature variation, wind pressure and atmospheric pressure change the volume of air inside the IGU, these small volumes of air will flow in and out of the unit through the capillary or breather tubes, which are attached to larger tubes (spacers), filled with desiccant. The theory is that these tubes will allow air movement while absorbing moisture from the air entering the system, thus ensuring that no moisture is able to enter the IGU assembly through the breather tube once sealed. If small amounts of moisture are able to enter the IGU, it will be absorbed by the large amount of desiccant located inside the spacer.

Various types of breather devices and capillary tubes have been used in the past. Two such capillary tubes are fully disclosed in PCT publication numbers 2017064166 and 2017064160, assigned to the assignee of the present disclosure. In accordance to the aforementioned application 2017064166, a connector (I) connects two hollow profiles in IGU. The connector (I) is provided with a cavity for producing a passage in the IGU (II) from the interior pane gap (12) to the exterior. The cavity, which is closed by a membrane, serves to produce pressure equalization between the atmosphere and the inner disc space of an insulating glass unit in the finished insulating glass unit. In accordance to the aforementioned application 2017064160, a corner connector (I) connects two hollow profiled strips in IGU. A capillary tube is solidly enclosed in the corner region of the corner connector (I) that produces a connection between the inner pane interspace (12) and the surroundings.

Although the aforementioned types of connectors are useful, it has been found to consume more manufacturing time owing to the below reasons. The connector (I) described in 2017064160 comprises of three child parts that require separate assembly time. Further the capillary needs to be bent and assembled into the connector (I) which again consumes some level of assembly time. Lastly there exists the challenge of insertion of the capillary tube into the desiccant filled hollow profile which requires skilled labor. Similarly, the corner connector (I) described in 2017064166 involves mounting of recess/ cavity in the corner connector (I) and sealing of the recess with gas-permeable and water vapor-tight membranes. Although the membrane is integrated directly in the course of the injection molding process, the sealing of IGU at job site and mounting of recess/ cavity at manufacture site are challenging.

A breather device disclosed in U.S. patent number 3,771,276 involves drilling of the semi-solid spacer material for insertion of the capillary tube. Referring to U.S. patent number 4,850,175 describes installation of capillary tube in an aluminium spacer of an IGU which is complex in a continuous process and involves complexity during IGU handling, transit and installation at job site. Hence there is a need for much simpler solutions for ensuring pressure equalization inside an IGU.

The objective of the present disclosure is to provide an IGU integrated with a pressure equalization mechanism that can be manufactured by a simple process and one that does not involve any challenges with respect to assembly of any capillary tubes. The present disclosure relates to an IGU pressure equalizer that is simple to manufacture and implement. There is no separate step required for the installation of a capillary. It must also be noted that there is no drilling of spacer frame or connector because the capillary-like recess is provided by injection molding during the manufacture of the pressure equalizer.

The present disclosure relates to an IGU pressure equalizer comprising a corner key for connecting a spacer frame and a corner plug firmly cast within an aperture present in the corner key. The corner plug is provided with a capillary-like recess which along with the aperture of the corner key connects the enclosed space between the two opposing glazing panels of the IGU with the external environment. This allows for the exchange of air between the enclosed space and the external environment and ensures no moisture build-up inside the IGU.

Summary of the Disclosure

In one aspect of the present disclosure, an insulating glazing unit (IGU) pressure equalizer for equalizing pressure in an enclosed space provided by two opposing glazing panels separated and held together by a peripheral hollow profile is disclosed. The IGU pressure equalizer comprises of a corner key and a corner plug. The corner key comprises of a first arm and a second arm connected together by a base plate having an aperture. The first arm is inserted into one end of the hollow profile and the second arm is inserted into the other end of the hollow profile. The corner plug comprises of a tubular body provided with an enlarged knob structure at one end. The tubular body comprises of a capillary-like recess defined in its central region running through the length of the tubular body and the knob structure. The knob structure of the corner plug is firmly cast within the aperture present in the base plate of the corner key. The aperture of the corner key together with the capillary-like recess defined in the tubular body of the corner plug establishes a passage from the enclosed space between the opposed glazing panels to the external environment.

In one other aspect of the present disclosure, an IGU comprising a first glazing panel and a second glazing panel opposed to each other and held together by a spacer frame provided at the peripheral margin of the two opposed glazing panel is disclosed. The spacer frame comprises of a hollow profile bent into a frame having two ends that are connected by a corner key firmly cast with a corner plug. The hollow profile defines an enclosed space therebetween the two opposing glazing panels.

In another aspect of the present disclosure, a method for equalization of pressure in an insulating glazing unit (IGU) is disclosed. The method comprises the steps of: connecting a spacer frame using the corner key; firmly casting a corner plug into the aperture of the corner key; providing two glazing panels on either side of the spacer frame; sealing the two opposing glazing panels to assemble an IGU; sealing the distal end of the corner plug away from the corner key with a sealant; transporting the manufactured IGU to a job site, cutting away the corner plug at a constriction portion, allowing pressure equalization through the capillary-like recess provided in the tubular body of the corner plug and sealing the cut away end of the corner plug with the sealant.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings

Embodiments are illustrated by way of example and are not limited to those shown in the accompanying figures.

FIG. 1 illustrates a cross-sectional view of a corner key, according to one embodiment of the present disclosure;

FIG. 2 illustrates a top view of a corner key, according to another embodiment of the present disclosure;

FIG. 3A illustrates a cross-sectional view of a corner plug, according to one embodiment of the present disclosure;

FIG. 3B illustrates a top view of the corner plug, according to another embodiment of the present disclosure;

FIG. 3C illustrates an external view of a corner plug, according to another embodiment of the present disclosure;

FIG. 4 illustrates an external view of a corner plug, according to yet another embodiment of the present disclosure;

FIG. 5A illustrates a hollow profile, according to another embodiment of the present disclosure;

FIG. 5B illustrates a spacer frame connected by a corner key and corner plug, according to another embodiment of the present disclosure;

FIG. 6A illustrates an IGU fitted with the corner key and corner plug, according to one embodiment of the present disclosure;

FIG. 6B illustrates a callout P depicted in FIG. 6A;

FIG. 7 illustrates an exploded view of an IGU constructed in accordance with the disclosure; FIG. 8 illustrates joint inspection of an IGU, according to one embodiment of the present disclosure; and

FIG. 9 depicts a flow chart for a method for equalization of pressure in an insulating glazing unit (IGU) using the present disclosure.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the invention.

Detailed Description

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar parts. Embodiments disclosed herein are related to an IGU pressure equalizer.

A corner key 100 according to one embodiment of the present disclosure is illustrated in FIG. 1. The corner key 100 comprises of a first arm and a second arm 110a, 110b joined together by a base plate 120. The base plate 120 is provided with an aperture 130 that covers almost more than 50% of the total surface area of the base plate 120. The first arm 110a and the second arm 110b joined at the base plate 120 are aligned perpendicular to each other. In one embodiment of the present disclosure, the angle between the first arm 110a and the second arm 110b is 90 °. In another embodiment, the angle between the first arm 110a and the second arm 110b can differ from the 90 ° angle by 2 °. In one embodiment of the present disclosure, the first arm 110a and the second arm 110b may be provided with one or more ridges 140. The ridges 140 are raised angular projections that provide for desired friction between the corner key 100 and the hollow profile 300 when the corner key 100 is inserted into the two ends of the hollow profile 300 for connecting the hollow profile 300 (as illustrated in FIG. 5A). In alternate embodiments, the corner key 100 may also be designed to achieve desired friction without the presence of the ridges 140.

In one embodiment of the present disclosure, the first arm 110a and the second arm 110b have a length L ranging between 20 and 50 mm; and a width W ranging between 6.5 mm and 26.5 mm. This width W is always less than the diameter of the hollow profile 300 to enable the insertion of the first arm l lOa and second arm l lOb of the corner key 100 into the hollow profile 300. In another embodiment, the aperture 130 has a diameter D not greater than or equal to 2 mm.

The first arm llOa and the second arm 110b are thus adapted to be inserted into the two ends of a hollow profile 300 (as illustrated in FIG. 5A) to provide a connection between the hollow profile ends. The corner key 100 when inserted into a hollow profile 300 helps in creating a spacer frame 320 for an IGU that is provided at the peripheral margin of two opposing glazing panels thereby providing an enclosed space therebetween. The aperture 130 of the corner key 100 provides for a passage between the enclosed space between the glazing panels and external environment.

FIG. 2 illustrates a top-view of the corner key 100. The geometry of the corner key 100 should not be taken to restrict the scope of the present disclosure and are provided only for teaching purposes. In practice any geometry of the corner key that would allow its insertion into the hollow profile 300 and one that would provide the desired level of friction between the corner key and the hollow profile 300 are enabled by the disclosure and hence would fall within the scope of the present disclosure.

A corner plug 200 according to one embodiment of the present disclosure is illustrated in FIG. 3A. The corner plug 200 comprises of a tubular body 210 having a distal end 220a and a proximal end 220b. The proximal end 220b of the tubular body 210 is provided with a knob structure 230. The tubular body 210 is further provided with a capillary-like recess 240 defined in its central region running through the length of the tubular body 210 and the knob structure 230. FIG. 3B illustrates a top-view of the corner plug 200 depicting the capillary like recess 240 running through the entire length of the tubular body 210 and the knob structure 230.

The capillary-like recess 240 comprises of a first opening 250a provided at the distal end 220a and a second opening 250b provided at the proximal end 220b. The first opening 250a of the corner plug 200 lies in the external environment while the second opening 250b of the corner plug 200 lies within the enclosed space between the two glazing panels of the IGU, when assembled in an IGU. Thus the capillary-like recess 240 connects the external environment to the enclosed space between the glazing panes and allows for air communication between the same.

In one embodiment of the present disclosure, the capillary-like recess 240 has a diameter D1 ranging between 0.7 mm and 2 mm. In one embodiment of the present disclosure, the tubular body 210 may comprise one or more constriction portions 260 along its length as shown in FIG. 3C. These constriction portions 260 help in cutting away the corner plug 200 during IGU pressure equalization procedure. However, the corner plug 200 depicted in FIG. 3A does not comprise of these constriction portions 260 and yet can be cut away along the length of the tubular body 210 during IGU pressure equalization procedure.

In multiple embodiments of the present disclosure, the tubular body 210 of the corner plug 200 may have any geometry, while the knob structure 230 of the corner plug 200 has a dimension relative to the aperture 130 of the corner key 100. This ensures firm casting of the knob structure 230 of the corner plug 200 into the aperture 130 of the corner key 100 during IGU pressure equalization procedure. In one embodiment as shown in FIG. 4, the capillary-like recess 240 has a diameter D1 ranging between 0.7 mm and 2.0 mm. In another embodiment, the tubular body 210 pf the corner plug 200 has a length LI ranging between 20 mm and 70 mm; and a width W1 ranging between 2.8 mm and 3.2 mm. In another embodiment, the knob structure 230 has a length L2 ranging between 7 mm and 7.5 mm; and a width W2 ranging between 5 mm and 5.5 mm.

The corner key 100 and the corner plug 200 are extruded profiles made from polycarbonate, acrylonitrile-butadiene-styrene (ABS), nylon, polypropylene, polystyrene, plastic, ceramic selected from the group consisting of silicon carbide, zirconia or alumina, glass composite selected from the group consisting of polymer matrix composite, metal matrix composite or cermet. In another embodiment, the corner key 100 and the corner plug 200 can be extruded from metals selected from the group consisting of steel, or aluminium or alloys thereof. In an alternate embodiment, the corner key 100 and corner plug 200 can be prepared as a single extruded profile, wherein the corner plug 200 is firmly cast into the aperture 130 of the corner key 100 during manufacture. In embodiments where the corner plug 200 is made of flexible material such as polymers listed above, cutting away of the corner plug 200 can be done using simple tools available at job sites. In embodiments where the corner plug 200 is made of rigid material such as metals then cutting the corner plug 200 may be performed using suitable tools such as wire, scissors, cable cutters etc.

In yet another alternative embodiment, the capillary-like recess 240 can be manufactured to be closed or self-sealed at the first opening 250a at the distal end 220a of the corner plug 200. This embodiment eliminates the need for sealing the capillary-like recess 240 post the assembly of the IGU.

FIG. 5A illustrates a hollow profile 300 that comprises of perforations 310 distributed along the length of the hollow profile 300. The hollow profile 300 is continuously produced and is bent to form a frame and coordinates with the peripheral margin of the opposed glazing panes to form a spacer frame 320 as shown in FIG. 5B. In a most preferred embodiment, the spacer frame 320 is rectangular in shape, the shape in which most of the insulating glazing units is manufactured. In alternate embodiments, the spacer frame 320 may be non-rectangular. In another embodiment, the spacer frame 320 is filled with a desiccant 340. The hollow profile 300 comprises of a first side wall 1, second side wall 2, interior wall 3 and an outer wall 4.

The spacer frame 320 comprises of two free ends 330a and 330b. The two free ends of the spacer frame 320, viz., 330a and 330b are connected together through the corner key 100. The first arm l lOa of the corner key 100 is inserted into the free end 330a of the spacer frame 320 and the second arm l lOb of the corner key 100 is inserted into the free end 330b of the spacer frame 320. The width W of the first arm l lOa, second llOb is less than the width W3 of the free ends 330a, 330b of the spacer frame 320. This provides for a fit between the spacer frame 320 and the corner key 100. The spacer frame 320 when connected by the corner key 100 has the aperture 130 arranged on the outer edge of the spacer frame 320 as shown in FIG. 5B. The figure further illustrates the corner plug 200 cast firmly within the aperture 130 of the corner key 100. The knob structure 230 of the corner plug 200 mates with the aperture 130 of the corner key 100.

FIG. 6A illustrates an insulating glazing unit (IGU) 400 comprising two opposed glazing panels 410, 420. In one embodiment of the present disclosure, the two opposing glazing panels 410, 420 may be glass and / or polymers. In another embodiment, the two opposing glazing panels 410, 420 may be selected from a flat glass, float glass, quartz glass, borosilicate glass or soda- lime glass. In an alternate embodiment, the insulating glazing unit may also comprise of more than two glazing panels.

The two opposing glazing panels 410, 420 are held together by means of a spacer frame 320 arrange at the peripheral margin of the glazing panels 410, 420. The first side wall 1 and the second side wall 2 of the spacer frame 320 (shown in FIG. 5A) are provided with a primary sealant so that the first glazing panel 410 and the second glazing panel 420 are fastened thereto. The enclosed space 430 between the glazing panels 410, 420 is delimited by the first glazing panel 410, the second glazing panel 420 and the interior wall 3 of the spacer frame 320. The two opposing glazing panels 410, 420 are attached to the spacer frame 320 via a primary sealant that enables a good sealing of the enclosed space 430 between the glazing panels 410, 420 from the external environment. This prevents penetration of moisture and loss of any existing gas filling that may be done between the two opposing glazing panels 410, 420. The outer wall 4 of the spacer frame 320 and the first and second glazing panels 410, 420 define an outer space 440 between the panels. The outer space 440 between the glazing panels 410, 420 is preferably filled with a secondary sealant 450. The secondary sealing contributes to the mechanical stability of the IGU 400.

In one embodiment, the primary sealant preferably includes a polyisobutylene. The polyisobutylene can be a crosslinking or non-crosslinking polyisobutylene. In one other embodiment the secondary sealant 450 may be selected from the group consisting of silane-modified polymers, particularly organic polysulphides, silicones, room-temperature vulcanizing (RTV) silicone rubber, peroxidischvernetzten silicone rubber and / or addition-crosslinked silicone rubber, polyurethanes and / or butyl.

The spacer frame 320 is seen to be connected by the corner key 100 which is provided with a corner plug 200 firmly cast into the corner key 100. Further FIG. 6B depicts cut-away view of a call out P, which further illustrates the spacer frame 320, corner key 100 and corner plug 200 in detail. In one embodiment, the spacer frame 320 may be filled with a desiccant 340 for absorbing any moisture present between the two opposing glazing panels 410, 420 thereby preventing fogging. The desiccant 340 may also enable absorption of moisture from the incoming air entering through the spacer frame 320 thereby eliminating the entry of moisture into an enclosed space 430 between the two opposing glazing panels 410, 420. Hence preferably, all portions of the hollow profile 300 are filled with a desiccant 340, so that an effective drying of the incoming ambient air and the enclosed space 430 between the panels 410, 420 are ensured. The desiccant 340 may be selected from the group consisting of silica gels, molecular sieves, CaCF, Na SCp, activated carbon, silicates, bentonites, zeolites and / or mixtures thereof.

In such an assembled IGU 400, the second opening 250b provided at the proximal end 220b of the corner plug 200 is in the enclosed space 430 between the two opposing glazing panels 410, 420 and the first opening 250a provided at the distal end 220a of the corner plug 200 is in the external environment. The pressure equalization is thus directly between the environment and the enclosed space 430 between the glazing panels, which is particularly effective and simple to implement.

Following assembly of the IGU 400 as described in the before sections, the distal end 220a of the corner plug 200 is sealed using a structural sealant. The sealing prevents the ingress of moisture and dust from the environment. The corner key 100 once inserted into the spacer frame 320 has its first arm 1 lOa and second arm 1 lOb in the cavity of the hollow profile 300 and is completely hidden and rigid. An exploded view of the assembly of the IGU 400 is also depicted in FIG. 7.

Example 1

Air Gap Inspection Study

Double glazing units (DGU) comprising two glass panels held together by a spacer frame provided with pressure equalizer of the present disclosure were manufactured at a manufacturing site (M). The air gap between the two glass panels was inspected at five different inspection point’s viz., A, B, C, D and E distributed across the DGU as shown in FIG. 8. Air gap across the above mentioned points were also measured for conventional insulating glazing units devoid of any pressure equalization mechanism for comparative study. The air gap at the inspection points were measured at the manufacturing site (M) and later the units were transported to an installation site (I), which is at an increased altitude of 800 m. The air gap was again measured at installation site to monitor increase in air gap and IGU bulging. The results of air gap inspection study are tabulated in Table. 1.

Table 1: Air Gap Inspection Test

One among the 4 double glazing units (DGU) manufactured was integrated with a pressure equalizer of the present disclosure. Air gaps were determined at manufacturing site (M) and installation site (I). For the DGU integrated with a pressure equalizer, air gap was additionally measured after cutting away the corner plug and allowing for pressure equalization through the corner key and corner plug. From the table it is evident that a minimum of 2 mm and a maximum of 3 mm increase in air gap were observed among the DGUs at the central inspection point C.

The DGU integrated with the pressure equalizer showed an air gap of 12 mm at the manufacturing site and later showed a 15 mm air gap when measured at the installation site. Subsequently, the corner plug was cut and allowed for pressure equalization for a time period of 15 to 20 minutes. It should be noted that the time required for pressure equalization depends also on the height at which the installation of the IGU takes place, the time increasing with the increase in installation height. Re-inspection of the air gap after the above mentioned time interval recorded an air gap of 13 mm. This signifies that an air gap reduction of 2 mm during the time interval allowed for pressure equalization. With an increased time for pressure equalization (up to 40 minutes) the air gap reduction of 3 mm was observed that brought the air gap to its initial measurement of 12 mm.

Durability Testing

Durability of DGUs assembled according to the present disclosure was tested using EN 1279-1 standard in two parts where the moisture content of the DGUs were determined on assembly and after a period of two months from assembly. The frost/ dew appearance and of the DGUs were determined by standard JIS R 2309 on assembly and after a period of two months from assembly. The assembled DGUs had a sample size of 350 x 500 mm and an overall thickness of 27 mm.

Frost/ dew appearance was measured between -20 °C and -60 °C. The testing was carried out in two parts where the first part had the climate test conditions of 56 temperature cycles of 12 hours from -18 °C to +53 °C with slopes of 14 °C/hour. The second part of the testing was performed at a constant temperature of 58 °C and a relative humidity of 95% for 3 weeks. Following which the DGU samples were conditioned for 2 weeks at lab temperature. The results of the durability tests are tabulated in table 2.

Table 2: Durability Test Results

From the above table it is evident that the DGU integrated with the pressure equalizer of the present disclosure did not show any signs of frosting or visual deposition. The initial and final moisture levels were found to be well below the standard of 20% as per EN 1279-1 standard. The moisture penetration index (MPI) was also found to be below the standard value of 2.5 %.

Industrial Applicability

The insulating glazing unit (IGU) 400 of the present disclosure can be used as building interior glazing and building external glazing. The pressure equalizer of the present disclosure may also be used in multiple glazing units which are more susceptible to breakage due to the larger volume these enclose as compared to the standard units. The present disclosure provides for pressure equalization without the use of any capillary which are sensitive to handle and complex to assemble. The capillary-like recess 240 of the corner plug 200 is provided during the extrusion step of the corner plug 200 and hence does not involve any additional manufacture and assemble steps.

With the present disclosure the pressure equalization is carried out directly between the enclosed space 430 in the IGU 400 and the external environment, thereby making the process simple and efficient. The major advantage of using the pressure equalizer of the present disclosure is that they keep the glazing panels of the IGU 400 flat regardless of the changes in the atmospheric condition. Again, distortion in the uniformity of appearance and color of the IGU 400 unit that could possibly result from the uneven reflection of light caused by difference in pressure between the inside and outside of the IGU 400 is completely ruled out. By maintaining flat glazing panels by using the pressure equalizer of the present disclosure, the uniformity of appearance and color of the IGU 400 are greatly enhanced.

Although the present disclosure has been described with particular reference to the specific details of certain embodiments thereof, it is not intended that such details shall be regarded as limitations on the scope of the disclosure except insofar as included in the accompanying claims.

An exemplary method 500 for equalizing pressure in an IGU 400 according to one embodiment of the present disclosure is illustrated in a flowchart depicted in FIG. 9. The method 500 involves steps 510 to 580. In an embodiment, the pressure equalization in an IGU 400 may be carried out by implementing the steps of the method 500. The method 500 will be explained in conjunction with one or more components of the IGU 400 of the present disclosure. However, it may also be contemplated to implement the method 500 with other suitable insulating glazing units without deviating from the scope of the present disclosure and/or necessary modifications to the described components of the pressure equalizer.

The method 500 in step 510 comprises of providing a spacer frame 320 by connecting the two free ends 330a, 330b of a rectangular bent hollow profile 300 using a corner key 100 of the present disclosure. The two arms l lOa, l lOb of the corner key 100 are inserted into the two free ends 330a, 330b of the hollow profile 300 thereby connecting the hollow profile 300 to form a spacer frame 320. The corner key 100 not only establishes connection between the free ends 330a, 330b of the hollow profile 300 to provide a spacer frame 320 but also serves to connect the interior of an IGU 400 (after assembly) with the external environment after IGU 400 assembly. The spacer frame 320 may be filled with a desiccant material 340 by methods known in the art. The desiccant material 340 helps in absorbing moisture from the air entering through the spacer frame 320 into the IGU 400. Silicon granules may preferably be used as the desiccant material 340.

In step 520 of the method 500, the corner plug 200 of the present disclosure is firmly cast into the corner key 100. The knob structure 230 provided in one end of the corner key 100 is inserted into the aperture 130 defined in the bottom plate of the corner key 100. Air communication between the interior of the IGU 400 (after assembly) and the external environment is made possible through the capillary-like recess 240 defined in the central region of the tubular body 210 of the corner plug 200 that runs through the entire length Ll and L2 of the corner plug 200. The first opening of the capillary-like recess 240 is in the external environment while the second opening of the capillary-like recess 240 faces the interior of the IGU 400 (after assembly). This enables direct communication and simple mechanism for pressure equalization.

In step 530 of the method 500, the first side wall 1 and second side wall 2 of the spacer frame 320 are applied with a primary sealant and provided with two glazing panels 410, 420 one on each side of the spacer frame 320. Butyl may be used as the primary sealant for arranging the two opposing glazing panels to the spacer frame 320. This ensure first level of sealing the space between the two glazing panels delimited by the first glazing panel 410, second glazing panel 420 and the inner wall of the spacer frame 320. The spacer frame 320 is arranged on the peripheral margin of the glazing panels as shown in FIG. 6A. This arrangement leaves a space 440 which is provided with a secondary sealant 450 in the next step 540. The step 540 establishes the final sealing of the enclosed space 430 between the two opposing glazing panels and the external environment and prevents any leakage of air into the enclosed space 430. Optionally the enclosed space 430 between the two opposing glazing panels may be filled with inert gas. In the following step 550 of the method 500, the first opening of the corner plug 200 facing the external environment is sealed using structural sealants. This sealing prevents ingress of air into the IGU 400. Such an IGU 400 assembled with the pressure equalizer of the present disclosure may be transported to other locations for installation.

The steps 510 to 550 are carried out at the IGU 400 manufacturing site while the following consecutive steps will be carried out at a job site prior to installation of the IGU 400. In step 560, the corner plug 200 is cut away just prior to the installation of IGU 400 to allow equalization of pressure. In embodiments where the corner plug 200 is provided with constriction portions 260, the cutting away of the corner plug 200 is carried out in these constriction portions 260. Common cutting tools available at job sites may be utilized for this purpose.

In the penultimate step 570, the IGU 400 is left aside for pressure equalization for a pre-calculated period of time. The capillary-like recess 240 of the corner plug 200 ensures pressure equalization with changes in ambient conditions. Pressure equalization time required for an IGU 400 depends on a number of factors as discussed in the earlier sections. However, the pressure equalization time required for the present disclosure is meagre compared to the pressure equalization time required by conventional capillary and breather devices described in the background of the present disclosure. It has been estimated that a DGU having a dimension of 1 x 2.5 m and a thickness of 24 (6mm glass 1 +12 mm air gap + 6 mm glass 2) mm requires a pressure equalization time less than or equal to 15 minutes.

In the final step 580 of the method 500, the cut away portion of the corner plug 200 is sealed using suitable structural sealants and proceeded with installation of the IGU 400. Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which they are performed.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Certain features, that are for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in a sub combination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.

The description in combination with the figures is provided to assist in understanding the teachings disclosed herein, is provided to assist in describing the teachings, and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other teachings can certainly be used in this application. As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such method, article, or apparatus. Further, unless expressly stated to the contrary, "or" refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Also, the use of "a" or "an" is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise. For example, when a single item is described herein, more than one item may be used in place of a single item. Similarly, where more than one item is described herein, a single item may be substituted for that more than one item.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent that certain details regarding specific materials and processing acts are not described, such details may include conventional approaches, which may be found in reference books and other sources within the manufacturing arts.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

List of Elements

TITLE: IGU PRESSURE EQUALIZER

100 Corner Key

1 lOa First Arm

1 lOb Second Arm

120 Base Plate

130 Aperture

140 Ridges

200 Corner Plug

210 Tubular Body

220a Distal End

220b Proximal End

230 Knob Structure

240 Capillary-like Recess

250a First Opening

250b Second opening

260 Constriction Portions

300 Hollow Profile

310 Perforation

320 Spacer Frame

330a First Free End

330b Second Free End

340 Desiccant

1 First Side Wall

2 Second Side Wall

3 Interior Wall

4 Outer Wall

400 Insulating Glazing Unit (IGU)

410 First Glazing Panel

420 Second Glazing Panel 430 Enclosed Space

440 Outer Space

450 Secondary Sealant

500 Method

510 Step

520 Step

530 Step

540 Step

550 Step

560 Step

570 Step

580 Step

L Length of First Arm 1 lOa and Second Arm 1 lOb

W Width of First Arm 1 lOa and Second Arm 100

D Diameter of the Aperture 130

LI Length of Corner Plug 200

W1 Width of Corner Plug 200

L2 Length of Knob Structure 230

W2 Width of Knob Structure 230

D1 Diameter of Capillary-like Recess

W3 Width of the First Free end 330a and Second Free End 330b

P Call out

Claims

We claim,

1) An insulating glazing unit (IGU) pressure equalizer for equalizing pressure in an enclosed space 430 provided by two opposing glazing panels separated and held together by a peripheral hollow profile 300 comprising:

a. a corner key 100 comprising a first arm l lOa and a second arm 110b connected together by a base plate 120 having an aperture 130, wherein the first arm l lOa is inserted into one end of the hollow profile 300 and the second arm 110b is inserted into the other end of the hollow profile 300; and

b. a corner plug 200 comprising a tubular body 210 provided with an enlarged knob structure 230 at one end, wherein tubular body 210 comprises of a capillary-like recess 240 defined in its central region running through the length of the tubular body 210 and the knob structure 230,

wherein the knob structure 230 of the corner plug 200 is firmly cast within the aperture 130 present in the base plate 120 of the corner key 100, wherein the aperture 130 together with the capillary-like recess 240 defined in the tubular body 210 of the corner plug 200 establishes a passage from the enclosed space 430 between the opposed glazing panels to the external surroundings.

2) The IGU pressure equalizer as claimed in claim 1, wherein the first arm l lOa and second arm 110b of the corner key 100 connected to the base plate 120 of the corner key 100 are perpendicular to each other.

3) The IGU pressure equalizer as claimed in claim 1, wherein the first arm l lOa and second arm 110b of the corner key 100 have a length ranging between 20 and 50 mm and optionally comprises of one or more raised ridges 140 to provide a desired friction between the corner key 100 and the hollow profile 300.

4) The IGU pressure equalizer as claimed in claim 1 , wherein the capillary like recess 240 of the corner plug 200 comprises of a first and second opening, wherein the first opening 250a is provided at the distal end 220a of the corner plug 200 and the second opening 250b is provided at the proximal end 220b of the corner plug 200.

5) The IGU pressure equalizer as claimed in claim 1 , wherein the capillary like recess 240 in the tubular body 210 of the corner plug 200 is about 0.7 to 2.0 mm in diameter Dl.

6) The IGU pressure equalizer as claimed in claim 1, wherein the aperture 130 provided in the corner key 100 and the knob structure 230 provided in the corner plug 200 have coordinated dimensions.

7) The IGU pressure equalizer as claimed in claim 1, wherein the length Ll of the corner plug 200 ranges between 20 to 70 mm.

8) The IGU pressure equalizer as claimed in claim 1, wherein the tubular body 210 of the corner plug 200 optionally comprises of one or more constriction portions 260 along its length for easing cutting and sealing of corner plug 200.

9) The IGU pressure equalizer as claimed in claim 1, wherein the corner key 100 and the corner plug 200 are extruded profiles made of polycarbonate, acrylonitrile-butadiene-styrene (ABS), nylon, polypropylene, polystyrene, plastic, ceramic selected from the group consisting of silicon carbide, zirconia or alumina, glass composite selected from the group consisting of polymer matrix composite, metal matrix composite or cermet, metals selected from the group consisting of steel, aluminium or their alloys thereof.

10) The IGU pressure equalizer as claimed in claim 1 compensates for a possible difference in air pressure between the external surroundings and the enclosed space 430 between the glazing panels through the capillary like recess 240 provided in the corner plug 200.

11) An insulating glazing unit (IGU) 400 comprising:

a first glazing panel 410 and a second glazing panel 420 opposed to each other and held together by a spacer frame 320 provided at the peripheral margin of the two opposed glazing panels comprising:

a hollow profile 300 bent into a frame having two ends that are connected by a corner key 100 firmly cast with a corner plug 200, wherein the hollow profile 300 defines an enclosed space 430 therebetween the two opposing glazing panels.

12) The insulating glazing unit (IGU) 400 as claimed in claim 11, wherein a capillary-like recess 240 provided in the center region of the tubular body 210 of the corner plug 200 connects the enclosed space 430 between the opposed glazing panels with the external surrounding.

13) The insulating glazing unit (IGU) 400 as claimed in claim 11, wherein the distal end 220a of the corner plug 200 away from the corner key 100 can be sealed with a sealant or is self-sealed.

14) The insulating glazing unit (IGU) 400 as claimed in claim 13, wherein the sealant is selected from the group consisting of structural silicon, acrylic resins, adhesives, butyl rubber, epoxy thermosets, fibrin glue, latex, polyurethane, rubber, urethane or varnish. 15) The insulating glazing unit (IGU) 400 as claimed in claim 11 characterized in that a concave or convex deformation of the float glass is reduced or prevented.

16) The insulating glazing unit (IGU) 400 as claimed in claim 11 wherein the enclosed space 430 has minimal or no increase in air gap.

17) A method for equalization of pressure in an insulating glazing unit (IGU) 400 comprising:

a. connecting a spacer frame 320 using a corner key 100 as claimed in claim 1 ;

b. firmly casting a corner plug 200 as claimed in claim 1 into the corner key 100;

c. providing two glazing panels on either side of the spacer frame 320;

d. sealing the two opposing glazing panels to assemble an

IGU;

e. sealing the distal end of the corner plug 200 away from the corner key 100 with a sealant;

f. transporting the manufactured IGU 400 to a job site;

g. cutting away the corner plug 200;

h. allowing pressure equalization through the capillary-like recess 240 provided in the tubular body 210 of the corner plug 200 for a pre-calculated time period; and

i. sealing the cut away end of the corner plug 200 with the sealant.

18) The method as claimed in claim 17, wherein the capillary-like recess 240 of the corner plug 200 allows simultaneous aeration in the two openings of the corner plug 200 to achieve efficient pressure equalization. 19) The method as claimed in claim 17, wherein the time period for pressure equalization is less than or equal to 30 minutes.