We want to talk to you about your heat flux application.  Contact us.

Phone: (540) 961-3576     Fax: (540) 953-3010      e-mail: mkt@vatell.com
 

Schmidt Boelter Heat Flux Gage

---

Conduction Cooled Scmidt Boelter

Standard Configuration:
Diameter:                      0.185"
Length:                         0.3"
Minimum Sensitivity:     150 microvolts/W/cm²
Time Constant:            10 mS
0-90% Rise Time        30 mS
Max. Temperature       150 °C
Nominal Resistance    < 100 ohms

Other geometries and configurations are available to meet your specific application requirements.

Water Cooled Schmidt Boelter

Minimum Diameter:       0.5"
Minimum Sensitivity:     150 microvolts/W/cm²
Time Constant:            10 mS
0-90% Rise Time        30 mS
High maximum temperatures are possible depending on the sensor geometry and application.
Nominal Resistance    < 100 ohms
 

More Information

    Vatell Corporation is proud to announce the newest addition to its product line, the Schmidt-Boelter gage.  Heat flux gages of this type have been in use for many years.  However, Vatell has  developed  an improved  version of  this  sensing instrument.

    Schmidt-Boelter gages are made by winding a spiral of Constantan wire around an electrically insulating wafer, then plating the turns on half  of  the wafer  with copper. This  process creates thermocouple junctions at the points on both sides of the wafer where the plating ends.  In a conventional Schmidt-Boelter gage, the thermocouples on one side of the wafer produce a first signal when a wave of heat energy reaches them, and the thermocouples on the other side of the wafer produce a second signal when the wave of heat energy reaches them.  The two signals combine to produce a second-order response.  With conventional construction the only way to achieve fast response is to use an extremely thin wafer.  However, this does not eliminate the second signal.
     The patented (US 6,186,661) Vatell design isolates thermocouples on the back of the wafer and directs heat around them directly into the housing.  Time response is inherently fast, and there is no second signal.  Furthermore, the wafer does not have to be extremely thin.  In fact, it is made thicker to reduce thermal resistance at the points of contact with the housing.  Vatell uses  wafers of aluminum nitride instead of anodized aluminum.  Forty turns around a 3.5 mm substrate produce a sensitivity of 250 microvolts per watt/cm2 and a first order response time of less than 10 milliseconds.
     Schmidt-Boelter gages of the new design will be offered in a variety of housings, conduction or water-cooled, for measurement of total or radiant heat flux.