Intek 100 User Manual

Page 4

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MODEL100 REV D.wpd


Rheotherm flow meters are available with various nonintrusive and intrusive transducer designs, but
they all use the same thermal sensing technique. Two temperature sensors are used — one is in thermal
equilibrium with the fluid and provides a fluid temperature reference, while the second temperature
sensor is located near a heater so that its temperature is slightly above that of the fluid. In a TU
transducer, the temperature sensors and heater are attached to the outside of the flow tube, whereas the
probe transducers have the sensors and heater located in the probe(s) that are inserted into the stream.
The amount of heat removed from the heated sensor by the stream is related to fluid velocity. Hence,
the measured temperature differential between the reference sensor and heated sensor is a function of
flow rate. For the Model 100 the non-linear output is approximately proportional to the logarithm of
flow. Intek, Inc. is licensed to use this patented and trademarked flow measurement technique.

Nonintrusive transducer

Example of

Example of


single probe

dual probe with

with NPT fitting

flange fitting



Use proper input power — Check the label on the electronics for the input power


Use reasonable care in handling the transducer. Do not try to disassemble the transducers;
there are no removable parts.

TU — excessive twisting or bending can damage the sensor. The flow tubes are thin-walled


Probes (NPT/2I, NPT/I, BF/2I, BF/I, etc.) — take care not to bend the probes or damage the

tips. Do not try to remove or turn the conduit junction box.


All TU sensors under TU¼ should be supported by the sensor shell, not the tube stubs. TU
sensors using GALB junction boxes or sensors without junction boxes can be supported with
pipe clamps or some other appropriate means. TU s with ____ can be supported using the
brackets machined into the junction box. Additionally, Intek sells separate support brackets.