Fiber-film probes have cylindrical thin film sensors and may be used as a substitute for gold-plated wire probes in liquids or in gas applications where more robust probes are needed. Fiber sensors are 70 µm diameter quartz fibers, 3 mm long, covered by a nickel thin film approx. 0.1 µm in thickness. The ends are copper- and gold-plated, leaving a 1.25 mm sensing length. The fiber is soldered onto the prong ends. Fiber probes for water applications have lacquer-coated soldering joints and prongs insulating them electrically from the surroundings.
Triple-sensor fiber-film probes are available in one straight configuration for gas applications only.
Tri-axial fiber-film probe (55R95)
Tri-axial sensor probes have three mutually perpendicular sensors, consisting of fiber films. The sensors form an orthogonal system with an acceptance cone of 70.4°. The prong ends are all perpendicular to the sensors. This gives minimum prong interference and increases the accuracy, when the three probe signals are decomposed into velocity components. Used for measurement of the U, V and W velocity components in an instationary three-dimensional flow field. Provides information for calculation of the full Reynolds shear stress tensor. Mounts with the probe axis in the main flow direction. The resulting velocity vector must be within the acceptance cone.
|Technical Data For Fiber-film Sensors|
|Thickness of quartz coating||0.5 µm|
|Sensor dimensions||70 µm dia, 1.25 mm long
The overall wire lenght is 3 mm
|Sensor resistance R20 (approx.)||6 Ω|
|Temperature coefficient of resistance (TCR) α 20 (approx.)||0.40%/°C|
|Max. sensor temperature||300°C|
|Max. ambient temperature||150°C|
|Min. velocity||0.05 m/s *|
|Max. velocity||350 m/s|
|Frequency limit fmax (CTA mode)||175 kHz|
* Influence from natural convection up to approx. 0.20 m/s.