Description
Gold-plated probes have 5 µm diameter, 3 mm long platinum-plated tungsten wire sensors. The wire ends are copper- and gold-plated to a thickness of 15 to 20 µm, leaving an active sensor, 1.25 mm, on the middle of the wire.
The probe body is a 1.9 mm diameter ceramic tube, equipped with gold-plated connector pins that connect to the probe supports by means of plug-and-socket arrangements.
They are designed for measurements in high-turbulence flows of one-dimension. The plating of the ends serves the dual purpose of accurately defining the sensing length and reducing the amount of heat dissipated by the prongs. This results in a much more uniform temperature along the wire than is the case for miniature wires. Another advantage is less flow interference from the prongs at the point of measurement due to the wider prong spacing. Both increase the accuracy at high turbulence levels.
Configurations
The Single-sensor gold-plated wire probes are available in five different configurations. The picture on the right shows the dimensions common for the probes.
Mounting: 4mm. Probe Supports.
Gold-plated wire probe, straight (55P01)
Probe with straight prongs and with the sensor perpendicular to probe axis.
This probe can be used when measuring mean and fluctuating velocities in free-stream one-dimensional flows. Mounts with the probe axis parallel to the direction of the flow.
Gold-plated wire probe, 45 deg. (55P02)
Probe with straight prongs and with the sensor at an angle of 45° to probe axis.
This probe measures mean flow velocities, flow fluctuations and Reynolds shear stress in stationary two- and three-dimensional flows. Mounts with the probe axis parallel to the direction of the mean flow. The probe is rotated to get the velocity components.
Gold-plated wire probe, right angle, parallel (55P03)
Probe with right-angled prongs and with the sensor parallel to probe axis.
Used when measuring mean flow velocities and flow fluctuations in places that are not readily accessible, e.g. in pipes. Mounts with the probe axis perpendicular to the direction of the flow.
Gold-plated wire probe, right angle, perpendicular (55P04)
Probe with right-angled prongs and with the sensor perpendicular to probe axis
Used in the same applications as 55P03, except that the sensor is turned 90°. This makes these probes suitable for boundary layer measurements, e.g. in pipes, as well. Mounts with the probe axis perpendicular to the direction of the flow.
Gold-plated wire probe, boundry layer (55P05)
Probe with offset prongs and with the sensor perpendicular to probe axis.
This probe is designed for use in boundary layers. The shape of the prongs permits measurements close to a solid wall without disturbance from the probe body, which is out of the boundary layer. Mounts with the probe axis parallel to the direction of flow.
| Technical Data For Gold-plated Wire Sensors | |
|---|---|
| Medium | Air |
| Sensor material | Platinum-plated tungsten |
| Sensor dimensions | 5 µm dia, 1.25 mm long |
| Sensor resistance R20 (approx.) | 3.5 Ω |
| Temperature coefficient of resistance (TCR) α 20 (approx.) | 0.36%/°C |
| Max. sensor temperature | 300°C |
| Max. ambient temperature | 150°C |
| Max. ambient pressure | Depends on the type of mounting |
| Min. velocity | 0.05 m/s * |
| Max. velocity | 500 m/s |
| Frequency limit fcpo (CCA mode, 0 m/s) |
90 Hz |
| Frequency limit fmax (CTA mode) |
400 kHz |
* Influence from natural convection up to approx. 0.20 m/s.
