Quality Control of Film
Increase of Gas Pressure
For quality control and development of advanced products it is not only necessary to know the actual gas pressure within the VIP but it is also important to measure the change of gas pressure.
Previous measurements took a long time to achieve reliable results. Therefore va-Q-tec developed several methods which allow us to obtain information on the increase of gas pressure within a short time period and thus to perform accelerated ageing tests.
The illustration above shows the rise of gas pressure within a specially prepared vacuum panel. Measurements are done with help of the va-Q-check® system. As the measurement was started within a low gas pressure area, it is possible to assess the increase rate of the gas pressure fairly accurately within two weeks.
These methods help va-Q-tec control the barrier properties of delivered films, the gas pressure of any produced VIP and to develop new and improved kinds of vacuum insulation products.
Long term investigations with 20 mm thick micro-porous Silica VIPs, which were wrapped into a metallized high barrier film, show that the gas pressure at ambient temperatures does not rise more than one mbar per year.(see Fig. 3)
That means the increase of gas pressure after 50 years is about 50 mbar. This corresponds to a rise of thermal conductivity to a maximum of 0.008 W/mK. Thus the lifespan of a 20 mm thick VIP can last 30 to 50 years. A good barrier against penetrating gases is an aluminium laminated film. This however causes heat leakage at the VIP edge and is thus only suitable for large vacuum insulation panels.
Metallized film, i.e. a very thin aluminium layer within a high barrier film avoids these heat bridges. Micro-porous Silica has the smallest pore size: smaller than 0.5 µm. Thus the thermal conduction of air is mostly suppressed even at higher gas pressures. Even at a gas pressure of 50 mbar the thermal conductivity of a Silica VIP is only 0.007 W/mK, not even double the value it would be at complete evacuation.
Durability of VIPs
The lifespan of vacuum insulation panels depends on the characteristics of the film, the size of the pores of the core materials and on the thickness of the panel.
The film of the VIPs drastically reduces the transmission of water vapour and air. A dry ambient condition for the VIP is very important, because high humidity can influence the VIPs film. Accordingly, the lifespan of a 10mm VIP is reduced to half compared with a 20 mm VIP. For 40 mm VIPs the lifespan doubles.
VIPs in industrial & technical applications
The basic advantage of va-Q-tec’s VIPs are a ten times better insulation performance compared to conventional insulation materials of the same thickness. The result is extremely thin walls with extremely high insulation performance.
In addition, we are constantly developing our VIPs. Among other things, new features are created, such as variable shapes (3D) and flexible VIPs, which open up completely new design and application possibilities. We constantly test and optimize the performance of our VIPs and pass on our knowledge and innovations to our customers.
Our products and advice will help you to realize your goals. Often, this process does not even change the current design of your application. va-Q-tec’s VIPs furthermore offer safety on all levels: minimal temperature fluctuations, protection of sensitive components, prevention of condensation problems, reduction of emissions and high cost efficiency.