The Heat Balance (HB) Series of IRt/cs measure
the internal temperature of the target material
non-invasively, by employing a patented heat
balance technique. A typical application in medical
equipment is monitoring or controlling the tempera-
ture of fluid transported through disposable tubing
when warming or cooling:
• Transfusion systems
• IV warming systems
• Dialysis systems
• Cardio-pulmonary bypass systems
• ECMO systems
• Blood analyzers
The IRt/c.01HB model pictured measures internal
fluid temperature. For this, it measures both tubing
surface and ambient temperatures, then calculates
the internal temperature necessary to maintain
heat balance. A convenient clip head provides a
reproducible mounting location for the sensor.
This can be quickly attached to new tubing and
removed from used tubing. Principles of Operation
Fluid at temperature Tf flowing in tubing transfers
heat via convection through thermal resistance Rf
to the tubing inside surface. This in turn conducts
heat to the tubing’s external surface through thermal
resistance Rt. This then transfers to the environment
via radiation and convection thermal resistance Ro.
Other temperature values are: the wetted surface
of the tubing (Tw); outside surface of the tubing (Ts);
the local ambient (Ta).
Employing the method of thermal analysis with
electrical analogs: current = heat flow; voltage =
temperature, the heat transfer equation may be
written as follows:
The IRt/c-HB Series measures both Ts and Ta, and sol -
ves this equation automatically for fluid temperature
Tf, providing a highly accurate method of monitoring
or controlling the temperature of interest.
The configuration shown above is model IRt/c.01HB-
J-37C with its convenient tubing clip. Any of the IRt/c
models can be configured for the HB calculation.
Contact CleverIR for further details.