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After introducing the basic knowledge of argon, we know that hollow glass filling can help improve energy saving, so it is necessary to fill it. Let's see how to inflate?First look at the basic knowledge about inflation. The amount of air in the hollow glass depends on the internal volume of the hollow glass, 

V=H * W * T * 0.001 (Volume Litre = Height * Width * Air Layer Thickness * 0.001). 

According to experience, the number of liters required to inflate a unit of insulating glass is 1.5 times the volume of the insulating glass. Since the density of argon is greater than that of air, from the perspective of ensuring the quality (concentration) of the charging and shortening the time, the correct charging position should be with the argon filling hole on the bottom and the air output hole on the top.In a nutshell, there is two inert gas charging methods for insulating glass, namely, fully automatic online air curtain type filling, and manual charging tapy filling. The second method is mainly represented by Jinan LIJIANG Automation Equipment Co,.ltd. See the below video for the fully automatic online air curtain method.

Then, which of the two methods should be adopted should be determined by the characteristics of inflation and production requirements, that is (1) inflation cannot affect the production speed of insulating glass, otherwise, it will become a bottleneck in the production of insulating glass; (2) The physical properties of argon, specifically, the density of argon is greater than that of air.

Gas Filled with Insualting Glass Processing 1

Gas Filled with Insualting Glass Processing 1

The production efficiency of insulating glass depends on the slowest process. Inert gas and air have different molecular weights, and manual inflation is used. If the inlet speed is less than the outlet speed, the time is too long and it will become a bottleneck of the production capacity; but the outlet speed will cause turbulence in the air layer, which must meet the requirements The concentration and time are also very long, the so-called haste will not reach; if it is too fast, the internal pressure will be greater than the normal atmospheric pressure, causing the glass to break.

In the air-curtain inflation method, the two pieces of glass are separated, and the gas is from bottom to top, which can ensure both speed and concentration. According to reports, a glass deep-processing company in the United States adopts the air-curtain inflation speed. The time of each piece is less than 20 seconds, and the concentration is above 90% per piece. Therefore, from the perspective of inflation concentration and production efficiency, the online air curtain is better than manual inflation and should be considered.

We know from the physical characteristics of argon that argon is colorless, odorless, and non-toxic. We cannot distinguish between the gas-filled hollow glass and ordinary hollow glass with the naked eye, and cannot determine the concentration of gas-filled hollow glass. Therefore, we must use specific methods to detect the gas concentration of inflated insulating glass, including two things: the initial content (concentration) of inert gas and the ability to detect the inert gas retention of insulating glass.
In view of the current two major systems of foreign insulating glass testing standards, namely the European standard EN1279 and the American standard ASTM2188/89/90, only the European standard provides for this, and our introduction will focus on this.

Part 3 of EN1279 specifies the long-term testing methods and requirements for the argon seepage rate and concentration tolerance of insulating glass. The purpose is to ensure that the amount of inert gas filled in the hollow glass cavity is sufficient to ensure the thermal performance of the insulating glass during its life. Or the improvement of sound insulation performance; 

Part 6 of EN1279 is the quality control of the production process, which stipulates the tolerance and quantity of the initial inflation concentration of insulating glass. The initial concentration is 85%, the tolerance is -5%-+10%, that is, the acceptable concentration range is 80%-95%.

Part 3 and Part 6 of EN1279 stipulate that the method for detecting the concentration of inert gas in a hollow glass is to use a gas chromatograph to analyze the inert gas sample drawn from the hollow glass cavity. In a nutshell, the use of this method to detect the concentration of the hollow glass requires a sampling plug before the production of the hollow glass. During detection, insert a gas-tight syringe into the sampling plug of the hollow glass component to draw the gas in the spacer layer into Then, push the gas in the syringe into the spacer layer. After repeating this process twice, draw the gas sample into the syringe, and then inject the gas in the syringe into the adsorption column of the gas chromatograph, and record the chromatogram. The method is characterized by high accuracy, wide range, and can detect any concentration from 5-100%. 

But the disadvantages are 

(1) the test is destructive, and the sealing performance of the insulating glass after the test has been destroyed; 

(2) the test time is too long, the test time for a group of 20 inflatable insulating glass is at least 8 days, according to EN1279, the most Up to 4 days;

(3) The equipment investment is large, and the inspection needs to be carried out by professionals, and it can only be carried out in the laboratory, not on the construction site or the window glass of existing buildings.EN1279 stipulates that for the sample testing of gas-filled insulating glass, it is necessary to record the ambient temperature and air pressure during the production of the insulating glass, and then extract 6 pieces of insulating glass, of which 2 pieces need to be subjected to aging experiments. 

The sample size: 4+12+4, 352 (± 2mm) x502 (±2mm), must comply with the system regulations, EN1279-6 is mandatory, it stipulates that every 1000 pieces of inflatable insulating glass produced every day, 1 piece of insulating glass, at least 3 pieces per day, if the daily production is less than 100 pieces, Then 1 piece is detected. 

Sample detection steps: 2 pieces of insulating glass were subjected to a modified aging test according to 1279-2, including 27 high-humidity temperature cycles (instead of 56), 4 weeks of constant temperature, and horizontal humidity cycles (instead of 7).EN1279 Part 3 stipulates that the annual argon leakage rate is Li <1%, a-1. Generally speaking, the Li of most inflatable insulating glass is between 0.5-0.8%, but sometimes it can be as low as 0.1-0.3%

After the aging experiment of gas-filled insulating glass, we found that (1) different hollow glass structures exhibit different argon retention capabilities, that is, sealing capabilities; (2) even if there is a leakage of argon, it can still be Through the inspection of the dew point temperature of the hollow glass -40℃. From this, we can infer that it is more stringent than the dew point temperature to judge the sealing life and ability of insulating glass by insulating glass's ability to hold inert gas. Although different hollow glass structures can hold inert gases differently, we can always find common things to tell everyone how to improve the insulating glass's ability to hold inert gases. include: The choice of sealant, gusset spacers or continuous elbow spacers, the longest inert gas channel, the insulating glass should be able to withstand repeated expansion and contraction movements, and the performance of the auxiliary materials of the insulating glass should be as close as possible to the glass. The appropriate desiccant is 3A molecular sieve.

Needless to say, from the perspective of sealant, insulating glass must choose butyl rubber as the sealant. Although the MVTR of polyurethane is lower than that of polysulfide glue, it is higher than polysulfide glue in terms of argon leakage rate.

Polyurethane, polysulfide glue, or silicone glue, their functions are all structural and cannot be used as sealants. Therefore, to improve the sealing of insulating glass, a double seal must be used first. In fact, argon filling can improve the thermal performance of the hollow, and the cost is low. Therefore, in North America, the argon-filled hollow has been growing rapidly recently. Statistics show that: in 1970, 14% of windows in the United States were hollow; in 1982, the best-performing hollow configuration was white glass and air; in 1986, 1% of insulating glass was filled with argon; but by 1988 it reached 25%; In 2001 at the beginning of the century, it reached 70%.

Although for some reason, the existing ASTM standard does not provide for the detection of inert gas, the North American Insulating Glass Manufacturing Alliance (IGMA, also can be translated as North American Insulating Glass Association) and the US Insulating Glass Certification Committee on the content and aging of inert gas After the experiment, the retention ability is clearly mandatory. Otherwise, even if it passes the standard test, it will not pass the certification, and the insulating glass will not be affixed with the IGMA or IGCC logo! Obviously, this kind of on-site detection using gas chromatography is impossible and impossible. In addition, we found that other countries are using another method, the high-voltage electric spark method. The test principle of this method is that the test instrument contacts the surface of the hollow glass, the high voltage generated by the instrument causes the gas in the hollow glass to generate electric sparks, and the spectrometer in the instrument calculates the gas content through the received electric spark analysis. The detection method is to place the hollow glass sample vertically, 50mm away from the left and right sides of the hollow glass, and evenly take 5 points from top to bottom to measure the gas content, and take the arithmetic average of 10 points as the gas of the sample content. The biggest advantage of this method is that it is non-destructive, fast, and can achieve laboratory accuracy comparable to that of gas chromatography.

In summary, the significance of manufacturers using this argon gas detection instrument has the following aspects:Manufacturers of insulating glass equipment can use GG to detect argon-filled insulating glass. Without the presence of GG, the hollow manufacturer would not know the concentration of inert gas in the hollow air layer, and would not be positive for inflation;It is also very important for the insulating glass equipment industry because it makes manufacturers aware of the argon concentration in the insulating glass and whether it meets the requirements;For the end-user, it is of greater significance to improve the sealing life and thermal performance of the product; it will help the insulating glass manufacturer to improve the production management and QC quality; on the contrary, if the manufacturer does not improve the production management, it will compete Handed over to the opponent; Filling with inert gas can also increase the selling point of the product and become a marketing tool; Argon filling can improve the central and total K value of the hollow glass, reduce the condensation of the glass on the indoor side, and improve the comfort level;Filling with inert gas either does it or doesn't do it, but it cannot do it badly. 

This method provides a powerful means for enterprises to make argon-filled insulating glass.It should be pointed out that compared with gas chromatography, this method is a younger method, so it must be compared with one year of experiments to demonstrate its accuracy. After a year of rigorous comparison and testing, the North American insulating glass industry officially recommended this testing method to the industry. M. Webber, the executive director of the North American Insulating Glass Association, said in the newsletter: "This testing instrument provides a means for the certification laboratory to verify the initial concentration of the inert gas. It is different from the gas chromatography instrument or the oxygen analyzer. A truly non-destructive means of verification. Therefore, manufacturers have eliminated the need to use rubber plugs with other methods, and the inert gas of insulating glass can be repeatedly tested without affecting its quality." At present, North American laboratories rarely use gas chromatography because "gas chromatography instruments are outdated and obsolete" (David Bailey).

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