The hottest knowledge about insulating glass infla

With the vigorous implementation of national policies and regulations on building energy conservation and the gradual popularization of building energy conservation knowledge, people's demand for insulating glass with high energy-saving configuration is also increasing. The relative increase in market increment brought by the large-scale production of low radiation coated glass makes it possible to continuously increase the effective demand for high-performance insulating glass. As a result, low radiation coated insulating glass is more and more widely used and is in the ascendant. However, the application of low radiation glass has brought two problems that we have never encountered before: (1) the requirements for sealing life become more prominent when using off-line low radiation coating to make hollow glass; (2) After using low radiation glass to solve the problem of thermal radiation, it becomes very urgent to reduce the thermal convection in the hollow glass cavity. Filling the insulating glass with inert gas helps to improve the sealing life and reduce the thermal convection at the same time. The necessary initial filling concentration and air tightness are the basic guarantee to solve these two problems. This paper focuses on the relevant issues involved in improving the initial concentration of the inflatable insulating glass, such as the production process control and product quality inspection of the inflatable insulating glass, in order to help those manufacturers who have inflated the insulating glass but the concentration is less than 90% and those who are considering the use of the insulating glass inflation equipment to select the correct inflation equipment

1 basic knowledge of inflation

generally speaking, the inert gas used for inflatable insulating glass is argon, which is colorless, tasteless and non-toxic. Its molecular weight is 38% heavier than that of air, and its thermal conductivity is smaller than that of air

since the density of argon is higher than that of air, when the insulating glass is inflated, the argon filling (inlet) hole is at the lower end and the air outlet (exhaust) hole is at the upper end, so as to replace the air in the insulating glass and achieve the required argon concentration

the inflation process of insulating glass is essentially a process in which flowing gas transfers from one moving state to another. Whether the inflation quality is high or not is related to whether the gas produces laminar or turbulent flow. Therefore, the discussion on the inflation quality of insulating glass cannot be separated from the discussion on the basic concepts of laminar flow and turbulent flow

laminar flow and turbulent flow are the result of the interaction of inertial force and viscous force when viscous fluid moves. The main difference between viscous fluid motion and ideal fluid motion is that when the specified test range is exceeded, there is viscous force as well as inertial force. According to the characteristics of these two forces, their effects on the motion behavior of fluid micelles are different. According to the definition, the role of viscous force is to prevent the relative movement of fluid micro clusters, while the role of inertial force is just opposite to that of viscous force. Therefore, in viscous fluid flow, the flow behavior is determined by the results of these two forces. When the action of viscous force is far greater than that of inertial force, the gas movement produces laminar flow. On the contrary, when the action of inertial force is far greater than that of viscous force, the gas movement produces turbulence

intuitively, as the simplest image of fluid movement, laminar flow can be regarded as flow layers that are adjacent to each other and have "definite material meaning", or it is an extension of slip movement without mutually moving "fluid line elements". Simply put, laminar flow is the stratified flow of fluid. At this time, the fluid in motion bears Newtonian viscous stress, and there is no essential difference with the mechanical mechanism of the solid resisting each other's sliding motion. The basic characteristics of turbulence are vorticity, irregularity, randomness, diffusion and dissipation. It is a vortex structure with different sizes and frequencies, which makes its physical quantities show irregular randomness to the changes of time and space

at present, the inflation quality of insulating glass in China is not high, which is largely caused by the turbulence generated in the inflation process. Assuming that the sensor of the inflation equipment only recognizes the concentration of the inert gas collected at the vent of the insulating glass, and the final concentration of the inert gas given by the laminar flow and turbulent flow of the inflated insulating glass also meet the standard requirements, people cannot distinguish the concentration trend of the inert gas of which insulating glass after diffusion with the naked eye. If the high-pressure discharge method is used to detect the initial concentration of this kind of inflatable insulating glass, the concentration obtained will be higher than the actual concentration after diffusion. There are two results: 1) if the manufacturer judges that the product with turbulence is qualified and delivered to the customer or sent to the laboratory for testing, the actual concentration after diffusion will be lower than the concentration at the beginning of the test. 2) This kind of inflatable insulating glass with obvious change in concentration will confuse the manufacturer, because the sealing of the product is flawless, and the product is tested only at the initial concentration

the above statement about laminar flow and turbulent flow of fluid is to reveal the possibility and characteristics of turbulent flow during the transition of fluid motion state during the inflation of insulating glass

2 effect of turbulence on inflation process and concentration measurement

when the aerated insulating glass generates turbulence, part of the air in the insulating glass cavity can not be replaced by the filled argon. Therefore, the initial concentration of the aerated insulating glass with turbulence is difficult to meet the requirements specified in the standard. In addition, the air still exists in the center of the hollow glass cavity due to the turbulence generated in the inflation process. When turbulence occurs in the insulating glass, the concentration detected by the sensor at the insulating glass exhaust hole should generally be higher than the turbulent air in the center of the insulating glass cavity, and the complete diffusion of the inert gas in the insulating glass takes 6~8 hours. If this method is used for detection, the measured concentration is significantly higher than the actual concentration after diffusion. Therefore, we cannot use this test method as a test method for inflatable insulating glass. Otherwise, under the condition of turbulence in the inflatable insulating glass, the wrong judgment of the inspector will be given. If there is turbulence in the inflatable insulating glass, the high-pressure discharge method shall be used to detect the insulating glass as close to the spacer as possible (see Figure 4). According to the three measurement points recommended by the manufacturer, the turbulent gas of the inflatable insulating glass, i.e. the air position, is avoided. The concentration given is the concentration of the inert gas. Therefore, it is necessary to get the correct concentration figure 8 hours after the inflatable insulating glass was placed 6~ Erdogan was born in a Muslim family in Istanbul in 1954. According to the survey, the initial concentration of inflatable insulating glass self inspected by some manufacturers is more than 90%, but the actual concentration measured by a third party is significantly lower than 90%, and some are even less than 70%. Through the appearance inspection of these inflatable glass seals with large concentration differences, it is difficult to find any sealing defects. Therefore, we infer that one of the reasons for this phenomenon is due to turbulence

however, this method belongs to the post inspection of product quality. After the aerated insulating glass is placed for hours, the second sealant is basically cured. If the concentration of the aerated insulating glass does not meet the requirements, it is time-consuming and laborious to rework the aerated insulating glass. In addition, there are two possibilities: (1) if the inflation method is not improved, we still cannot guarantee that the inflation concentration of the reworked product meets the requirements; (2) Using ordinary inflation methods, i.e. natural inflation, inflation and forced extraction, turbulence is inevitable. Even if the glass tested at random meets the concentration requirements, unless we have real-time monitoring data for each piece of glass during inflation, we cannot accurately ensure that the entire batch of inflated glass is qualified

it can be seen that unless the inflation equipment we use can effectively avoid turbulence, or always maintain a stable laminar flow in the inflation process, we cannot rule out the authenticity of the detected concentration. Further, under this condition, the correct way to ensure the concentration of inflatable insulating glass can only be to control the production process of inflatable insulating glass, rather than product quality control

3 production process control of inflatable insulating glass the concept of production process control of inflatable insulating glass is to ensure that the production process of inflatable insulating glass is under control, and to analyze, diagnose and monitor the operation technology and production process that affect the quality of inflatable concentration. Its role is to systematically arrange the quality control of the production process, focus on the factors that directly or indirectly affect the process quality, and formulate and implement the control plan to ensure the process quality. Argon is a colorless and odorless gas, and its inflation concentration is difficult to measure. At present, there are two test methods: (1) the sensor compares the gas collected from the exhaust hole with the set gas concentration to judge whether it meets the requirements; (2) The sensor dynamically compares the gas collected by the exhaust hole with the set gas concentration and gives the real-time curves of concentration, pressure and flow rate. It can judge the actual concentration of inflation not only from the concentration but also from the curve shape. Compared with the two, the second method is not only the comparison of two values, but also the description of the whole inflation process. It is the most advanced production control means for real-time monitoring of the inflation process

the quality control of the concentration of aerated insulating glass is characterized by post event, which belongs to the detection of unqualified products. The production control of the European insulating glass STANDARD EN actually refers to the measurement of the laminated concentration of inflatable insulating glass, which should be understood as the quality control or inspection of products, rather than the production process control in the real sense. According to the sampling inspection regulations for the initial concentration of inflatable insulating glass, 1 piece/1000 pieces/shift, at least 3 pieces. When each shift has less than 100 pieces of inflatable insulating glass, spot check 1 piece. It takes about 6~8 hours for the argon in the inflatable insulating glass to fully diffuse. Therefore, the detection of the initial concentration of argon in the insulating glass can only be carried out after the gas is completely diffused. Therefore, whether it is the detection of the concentration of inflatable insulating glass or the detection after the inert gas is completely diffused for 6~8 hours, it can only be used to judge whether the product is qualified or not. If the result of such sampling inspection is generally unqualified, it is too late to find the problem

to sum up, the main reason for the low initial concentration of inflatable insulating glass is the turbulence phenomenon during inflation. The significance of the production control of inflatable insulating glass lies in the real-time monitoring of the whole inflation process, so as to effectively avoid the turbulence phenomenon that may occur in the inflation process of insulating glass, and improve and ensure the stability of inflation quality

4 intelligent inflation technology

after knowing the basic inflation principle of insulating glass and the necessity of the production process of inflatable insulating glass, it is necessary for us to consider the main inflation technologies and specific methods. Generally speaking, the selection of inflation equipment can be considered from the technical characteristics of the equipment. In terms of the degree of combination with the insulating glass production line, the inflation technology is divided into inflation and off-line inflation; From the point of view of production automation, inflation technology is divided into automatic inflation and manual inflation. Generally speaking, inflation, as the name suggests, means that the inflation process is carried out on the insulating glass production line. The inflation process is completed after the upper frame of the insulating glass and before the lamination (such as lisek production line and Baichao production line). It has the advantages of high degree of automation, short inflation time and stable concentration, but the disadvantages are large waste of inert gas; Manual inflation