Fully tempered vacuum insulating glass features
Since the vacuum insulating glass invention in 1993, how to make the most advantage of VIG thermal property,how to make it fully tempered and applied in more industry was always the biggest technology difficulties for all scientists and researchers.
Till now ,most vacuum insulating glass units are annealed VIG,not fully tempered,this posts will analysis why fully tempered vacuum insulating glass unit is production difficulty and how HaanGlas solved this problem.
The development of VIG edge sealing technology
The vacuum glass edge sealing technology not only affect the overall VIG performance,but also a deciding factor whether the glass is tempered or not,the development of edge sealing technology can be classified into 3 stages:
Earlier, people used various plastic or resin materials to seal the edges to make vacuum glass. For example, PC, ABS, LDPE, PVC and other organic glass as sealing materials, and some guys even tried PVB,EVA that usually used in laminated glass.
This process is similar to laminated glass. Although these materials can bond and seal vacuum insulating glass, but the gas permeability and moisture permeability of most plastics and resin materials are far greater than that of glass, and most organic materials just achieved physically bonded of glass surface,it is difficult to ensure that the sealed edge does not leak. Once gas (including water vapor) penetrates, it will directly lead to weakening of the sealing strength, condensation in the interlayer, and glass mildew. In addition, as time goes by, the aging problem of organic materials also directly affects the service life of vacuum glass.
2.Low temperature glass frits.
Later, people tried to use low-melting point glass frit as a sealing material to make vacuum glass, that is: first place the low-melting glass frit at the edge of two adjacent glass panels to be sealed, and then use flame or electric heating to melt the frit and connect glass panels.
Because the low-melting glass frit used are usually lead-zinc-based (PbO-ZnO) glass frit, the lead metal is harmful to the environment and human health. Therefore, long-term use has environmental risks; at the same time, during the heating and sealing process will cause glass edge stress decreased. As a result, the production efficiency is greatly reduced and the processing cost is increased,most important is,heating temperature during sealing is generally 400°C ~ 500°C,the tempered glass plate will be annealed and al-ready tempered glass will have uneven surface stress and lost its safety performance.
The glass frit also caused many possible VIG quality problems after installation.Some project has up to 20-30% breakage ratio after installation..the unstable VIG quality also bring worries to project owners.
Low temperature metal edge sealing.
In past years,new edge sealing technology was invented–low temperature metal edge sealing technology.
The new technology used new low melting metals,especially Tin, to help sealing glass edge,during sealing,the glass edge temperature can be controlled below250℃，which ensures no stress changeand keep overall tempered glass strength.The silk screen edge not only hide the ugly metal solders,but also helped better joint between the glass and metal.Since 2015,some China vacuum insulating glass manufacturers have adopted this new technology and keep supplying fully tempered vacuum insulating glass in large scale.The test reports also showed the low temperature metal edge sealing VIG units has high impact resistance,high wind resistance,high temperature resistance and also safety once breakage happen.
Features of fully tempered vacuum insulating glass.
The tempered VIG units brings the application of vacuum glass into a new times.
High safety performance.
Nobody would like to be injured by large panel broken glass dropped from overhead.Actually whether it’s 5M,10M,50M and even 100M, there’s no difference,the sharp glass corners will cause serious injury and high possibility death,that’s the reason why annealed vacuum glass are usually installed in building height below 3 stories.
Tempered vacuum glass has high strength.It has both the advantage of tempered glass,and also perfect thermal and acoustic performance of vacuum insulating glass.
With surface stress >90Mpa,The tempered glass strength is 3-5 times that of normal annealed glass,high impact resistance.
Once glass is broken,it will break into small particles, 40-90small particles in an 50*50mm area,the light weight particles won’t cause injury to people when it dropped from the high levels.
In most high skyscrapers,insulated glass are widely used.
With the same safety performance and similar structure,vacuum glass can now been widely used in glass facade and replace traditional thick insulated glass panels.
Sometimes heat strengthened glass is used to eliminate the possibility of spontaneous breakage,for VIG,it’s the same.Even though heat strengthened glass strength is inferior,but as the windows and facade are still has some distance from people,there’s hardly no exterior impact that can cause glass breakage.
To resist the huge wind speed,or possible damages caused by hurricanes, laminated vacuum insulating glass are also available.With exterior laminated panels,overall glass strength is even higher .
As the 0.3mm vacuum space,the vacuum glass overall thickness is even stronger.
Coordinated deformation of inner and outer panels of vacuum glass ,Vacuum glass can achieve the best resistance to external forces when adopting same thickness glass.
The equivalent thickness of VIG is 85% that of VIG total thickness.Which means 10.3mm vacuum glass can be calculated as 8.7mm tempered glass,now vacuum glass max size has reached 1700*3200mm,with this strength and size,vacuum glass can totally stand the high wind speed,and exterior impact.
Fully tempered vacuum glass can be achieved by our advanced low temperature metal edge sealing technology,with fully tempered VIG, the vacuum insulating glass has high impact resistance,higher wind pressure resistance and more safety,which enable vacuum insulating glass been widely used in glass facade,glass windows and doors.
Even though tempered glass still has certain spontaneous breakage ratio,but this can be eliminated by heat soaking test ,or making it heat strengthened vacuum insulating glass for high rise buildings,it can help your wndows&doors get higher performance complying with NFRC and energy star.
HaanGlas is your turnkey fully tempered vacuum insulating glass manufacturer and supplier,we offer various substrate,coating options to help your next project more energy efficiency,kindly contact us for more info.