The application of capillary tube in double glazed units

Generally, both the production and installation of the insulated glass are in the same or very similar latitude range. Under the same conditions, the air pressure in the double glazed unitsis always the same as the external pressure. But when the insulating glass is made at low latitudes such as sea level and then installed at a higher latitude, if we still simply assume that the pressure inside the insulating glass is still the same as the external pressure between the two places, it cannot explain why the two pieces of double glazed units deflect outward, visually deformed, and even the l burst. This is because the pressure inside and outside the insulating glass when the insulating glass is produced is larger than the pressure at the time of mounting at a high latitude. If the pressure difference is too large and exceeds the strength of the glass itself, the hollow glass may be broken/or the structural rubber of the insulating glass may be broken, resulting in premature failure of the sealing of the insulated glass. The traditional way to solve this problem is to install a breathing tube or capillary tube on the sealing edge of the insulating glass. The function of the breathing tube and capillary tube is to continuously adjust the difference between the pressure in the air layer of the double glazed units and the external atmospheric pressure as the height changes, so that it achieves dynamic equilibrium. Previously, the approach adopted was to install a breathing tube when the height of the hollow glass window in transport exceeded 5,000 feet (about 1524 meters).

The application of capillary tube in double glazed units

Keep in mind that the use of a “snorkel” with a large internal diameter requires sealing at the final installation to prevent premature failure of the insulating glass seal. The disadvantage of this approach is that the overall performance of the insulating structure of the insulating glazing depends on the local door and window installer, rather than in the hands of the producer of the insulating glass window. Therefore, no matter how good the quality of the insulating glass is, there is a problem if the snorkel is not sealed at the end of the installation. One way to solve the problem is to replace the breathing tube with a capillary. It can be seen from Table 1 that the inner diameter of the capillary is smaller (about 1/10 of the breathing tube) and the tube is longer than the breathing tube, so that even if the capillary is not sealed, the whole of the hollow glass after installation at a high latitude can be ensured. performance. Despite this, so far, there is no laboratory data to support this statement (the practice). In fact, there is still debate in the North American insulating glass industry about the durability and longevity of insulating glass with capillary or snorkel installed; even if the insulating glass with capillary is tested by ASTM773/774, it does not mean that the actual sealing life can be reached. 5 years.

The application of capillary tube in double glazed units

    Evaluation of the snorkel and capillaries

Due to the use of argon to fill the insulating glass, one has to rethink the height limit problem seriously. The outside air is exchanged with the gas in the hollow glass through the breathing tube, and as a result, the concentration of the inert gas therein is greatly reduced within a few months after the installation of the insulating glass. When the hollow glass window filled with argon gas is transported to the mountains, in order to install the argon-filled insulating glass as much as possible in the latitude, without reducing the sealing integrity of the insulating glass, the breathing should be avoided as much as possible. tube. The durability of the insulating glass using the butyl rubber and the silicone rubber double-pass sealing structure has been demonstrated to have excellent structural integrity. In most cases, the strength of the glass itself becomes a factor in the highest latitude limit of the insulating glass. Two different cases of height limits: the altitude limit at which the insulating glass can be installed and the height limit in the transport of insulating glass.

The application of capillary tube in double glazed units

Insulating glass at the height limit of mountain transportation

In this case, when the cargo truck is driven by the insulating glass through the mountain road, the time of the air pressure change is relatively short. At this time, since the surface of the hollow glass on the vehicle is strong, the risk of bursting is small. If the insulating glass is installed in the window frame, the glass can flex freely outward, and when it is transported to a low latitude, the glass returns to the normal position. If only the insulating glass is transported (when the glass is only twisted together), the glass deflects outwards so that the glass “scratches” each other in contact with each other. In this case, special packaging should be used to ensure that there is enough space between the insulating glass to flex outwards to avoid bursting.

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