Tester indicates water vapor transmission rate.
Press Release Summary:
PERMATRAN-WÂ® Model 398 provides alternative for testing of medium- to high-barrier structures. Operating via WinPerm(TM) software, unit enables 2 films to be tested simultaneously at 2 different RH conditions. Automated temperature and relative humidity controls, as well as automatically determined equilibrium, minimize chance of operator error. Modular system offers two 50 cmÂ² test cells and allows control of up to 10 modules from single computer.
Original Press Release:
New Permatran-W® Model 398 Debuts at Eastpack
Minneapolis, MN (June 15, 2004) -MOCON, Inc. (NASDAQ: MOCO), the leading manufacturer of instrumentation equipment, adds a new unit to its line of water vapor transmission rate test systems.
The PERMATRAN-W® Model 398 Water Vapor Transmission Rate test system provides a low-cost alternative for testing of medium- to high-barrier structures. Each test cell has its own sensor, assuring greater throughput with accurate results. The unit's precise relative humidity (RH) testing enables two films to be tested simultaneously at two different RH conditions.
The PERMATRAN-W® Model 398 Water Vapor Transmission Rate test system operates via simple and intuitive WinPerm(TM), Windows® based software. Automated temperature and relative humidity controls, as well as automatically determined equilibrium, minimize the chance of operator error.
The unit offers two, 50 cm² independently operated test cells, each containing state-of-the art sensor technology. The system is modular, allowing the control of up to ten modules from a single computer.
The PERMATRAN-W® Model 398 conforms to the new ASTM Standard E-3981 and also comes with a set of three calibration films.
MOCON is a leading provider of instrumentation and consulting and laboratory services to medical, pharmaceutical, food and other industries worldwide. See www.mocon.com for more information.
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1Theory of Operation-ASTM Standard E-398 Accumulation Method
The accumulation method of WVTR measurement is a proven approach that provides accurate measurements for medium/high barriers. This test method involves a chamber containing a source of water that is separated from an accumulation chamber by the sample under test. The relative humidity (RH) within the accumulation chamber cycles between a low and high set point in response to the periodic introduction of a dry purge gas such as nitrogen.
When the test begins, a set of valves open this allows a stream of dry purge gas to flow through the inner chamber, reducing the RH in the chamber until the low RH set point is reached. The valves are closed, and the humidity level within the chamber increases gradually in response to permeation through the film. When the high RH set point is reached, the valves open once again and the cycle repeats.
The computer then records the WVTR after each accumulation state. The WVTR is based on the amount of time required for the RH within the chamber to reach the high set point. When measured WVTR becomes stable over repeated cycles, the film is at equilibrium.