P2.4 - Climate Chamber for a High Temperature Stability
- SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
- Proceedings SENSOR 2011
- P2 - Calibration, Maintenance, Monitoring
- M. Kühnel, F. Hilbrunner, T. Fröhlich - Technische Universität Ilmenau (Germany), K. Lieberherr - Lieberherr AG, Hefenhofen (Switzerland)
- 698 - 701
A fair amount of measuring and testing tasks require stable environmental parameter such as temperature and relative humidity. The devices based on the state of the art control the temperature and the humidity in the test volume by an influx of air reaching a long time stability of DeltaTtime ≥ 0.1 K. There are even more stringent requirements on the temperature stability in the field of research and development e.g. high precision force, weighing or interferometric length measurement technology. At the same time additional requirements for static air and absence of vibration in the test volume do exist. Due to the technical principle described above, devices based on the state of the art can not meet these demands.
In contrast to the state of the art the panel temperature of the presented climate chamber is controlled. Thereto a fluid is passing through all panels of the chamber except the base panel. The fluid temperature is controlled by an external cryostat which is connected to the chamber using flexible tubes. Due to this concept, the chamber and the cryostat can be placed spatially divided in different rooms. There are no motors and pumps in the vicinity of the climate chamber, which leads to a decoupling of the chamber from disturbances such as vibrations and electromagnetic fields. The manufacturing was made by Lieberherr AG, Swiss.
The verification of the chamber performance was carried out in a temperature range of TChamber = 10..40°C. In the given range the maximum temperature gradient in the chamber volume was determined to be DeltaTspatial = 1K. The stability of the temperature within 7 days was measured at Tchamber = 20°C to be DeltaTtime < 0.01K. Furthermore the heating and the cooling rate of the chamber were measured to be 0.25 K/min respectively 0.18 K/min.
Compared to devices based on the state of the art the temperature stability of the presented climate chamber is ten times better. Despite non circulating air the spatial temperature gradient is roughly on the same level. The gradient as well as the heating and the cooling rate could be further improved by applying fluid coils on the base panel as well. A key advantage of the chamber arises due to the spatially divided arrangement of the chamber and the cryostat. Due to the absence of motors, magnetic valves or any other electromechanical parts the chamber is decoupled from disturbances such as vibrations and electromagnetic fields.