Magnetic Field Exposure requires non-magnetic materials. By jacketing the fiberoptic cable in non-metallic materials, and by constructing the sensor tip from non-metallic or non-magnetic materials, Philtec sensors can be configured to perform measurements in very high magnetic fields. Successful applications to 12 Tesla have been made.
We recently delivered this sensor; a model D20 high-frequency sensor for 2 Tesla exposure.
PROBLEM
Quartz fibers have excellent transmission over long lengths, but they are very expensive and usually cost prohibitive. A recent customer asked for a model D171 sensor with 45 meter length for displacement measurements in vacuum and high magnetic field.
SOLUTION
A 3-piece cost saving system was devised where only nineteen 200µm quartz fibers were used to illuminate 10% of the model D171 probe area.
Part A – Two Ø 1000 µm Hard Clad Silica Fibers, 20 m long in air
Part B – Two Ø 1000 µm Bundles of Ø 200µm Silica/Silica (Quartz) Fibers, 24.5m long in vacuum
Part C – Ø 4320 µm D171 Glass Fibers, 0.5 m long in Vacuum
Part A has two Ø1000µm fibers at the connector interface:
Part B Ø1000 µm fiber bundles each have 19 fibers at the connector interface:
one transmits light and one returns reflected light.
Part B transmit fibers were randomly mixed with Part C glass fibers. Although Part B fibers illuminated just 10% of Part C fibers, this D171 sensor calibrated to an acceptable 70 mm displacement range. And therefore, the system cost was much lower than it would otherwise have been if all of the D171 fibers had been illuminated by quartz fibers.
Philtec specializes in the design of sensor systems for gaining access to hard to reach targets. In March 2019, several dozen model D47 sensors were delivered with long fiber optic cables and very small 90° probes as seen here. The fiber optic cable lengths varied from 21 ft. to 55 Ft. long
Send us a sketch or drawing of your application requirements. We’ll make a sensor configuration drawing for your review. Email sensors@philtec.com
CUSTOMER FEEDBACK
“We just got some feedback about the 9 sensors with special configuration and copper sheathing. They are quite satisfied by the sensors, which are well resisting against the 400°C. They have done several tests and measurement campaigns in laboratory and on flight.”
THE APPLICATION
Philtec has delivered 9 sensors to be used during helicopter flights to measurement displacement of engine components. The sensors have 40 mm displacement range and are designed for 400°C continuous tip exposure.
The sensors are equipped with the following options:
Option B – Connectorized Probe
Option C9 – Bendable Copper Cable Jacket, Part B
Option E2 – 3 m total fiber cable length
Option P – Polynomial Curve Fits
Option Q – Connectorized Power Supply and BNC Outputs
Option T6 – Custom 90° Tip with Threaded Probe Extension
Option T9 – 400°C High Temperature Probe Construction
CUSTOMER FEEDBACK
“I wanted to let you know the sensors worked as designed during our tests. I may follow up with Chris on a few specific questions as we begin to sift through all of our data. Thank you again for your professionalism and for all your support.” … Sincerely, VMR, Mechanical Engineer
THE APPLICATION
Five special right angle probes were delivered for a 1000°F tip exposure test.
