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
 

   

BF Heat Flux Transducer

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Advantages
- Low profile
- Flexibility- small bend radius.
- Low thermal resistance - little effect on measured parameter.
- Equal sensitivity for measuring heat flow in both directions.
- Output proportional in magnitude and polarity to heat flux.
- Calibrated individually to a NIST traceable standard
- Optional type T thermocouple (for temperature measurement) available.
 

**ALL BF Sensors are individually calibrated to a NIST traceable standard**

	BF-01	BF-02	BF-03	BF-04	BF-32
Size	32cm x 32cm	1cm x 1cm	5.1cm x 5.1cm (2inch x 2inch)	2.5cm x 2.5cm (1inch x 1inch)	3.96cm x 8.25cm
Active Area	936.27 cm2 (30.9cm x 30.3cm)	57.4 mm2 (8.2mm x 7.16mm)	22.42 cm2 (4.7cm x 4.77cm)	4.75 cm2 (2.18 cm x 2.18 cm)	3.5cm x 7.4cm
Sensor Thickness (adhesive tape is 0.127mm thick)	0.25mm	0.25mm	0.25mm	0.25mm	0.25mm
Thermal Conductivity	0.25 W/mºK	0.25 W/mºK	0.25 W/mºK	0.25 W/mºK	0.25 W/mºK
Minimum Sensitivity	150 mV / (W/cm2)	1.0 mV / (W/cm2)	50 mV / (W/cm2)	10 mV / (W/cm2)	30 mV / (W/cm2)
Response Time	~ 0.9 sec	~ 0.9 sec	~ 0.9 sec	~ 0.9 sec	~ 0.9 sec
BF Max. Temp.  (ºC)	170 (ºC)	170 (ºC)	170 (ºC)	170 (ºC)	170 (ºC)
Min. Bend Radius	30 mm *	30 mm *	30 mm *	30 mm *	30 mm *

* The adhesive that is supplied with the BF sensor will hold the sensor at a 60 mm bend radius

** Custom Sizes Available Upon Request **

We have specialized sensors designed to measure radiation and convection seperatly at the same location using BF Tecnology.  For more information on these products please visit CB32 Convection/ Radiation Sensor 

Construction
This transducer measures the rate of thermal energy flow per unit area (heat flux). When heat flows into or out of the transducer surface, a small temperature
difference develops across the thermal resistance of the transducer thermopile. Each thermocouple pair of the thermopile produces a voltage proportional to
heat flux. The total voltage across the thermopile is the sum of these voltages and indicates the direction and magnitude of heat flux.

Taking Measurements
Recorded voltage signals can be converted to their respective heat flux and temperature levels using the calibration information included with each transducer. Each transducer is calibrated to a NIST traceable standard. There are two connection wires associated with the basic BF Heat Flux Transducer; the positive and negative leads for heat flux. If purchased with a thermocouple, there will be a second pair of wires that are positive and negative leads for the thermocouple.

Mounting the BF Heat Flux Transducer
To take full advantage of the low thermal resistance of the BF Heat Flux Transducer, it should be mounted so that there is good thermal contact between the
sensor and the test surface. A concerted effort should be made to prevent any air bubbles, dirt, or water from becoming trapped between the transducer and
the test surface. Poor contact with the test surface may result in measurement errors, so Vatell recommends mounting the transducer on a smooth, clean, dry
surface.

Best results are achieved when using the adhesive backing that comes standard with the BF Heat Flux Transducer, because it is specially designed to insure
good thermal contact. If the adhesive backing is not suitable for a particular application, the use of a thermally conductive paste or grease should yield good results. Apply a thin, uniform layer of the paste to the sensor and then press the sensor gently to the test surface. Use the smallest amount of
paste possible. Not only is excess paste messy, but it can slow the response time of the sensor.

Any alternate, user-specific methods of attachment should be designed so that there is good thermal conduction from the BF Heat Flux Transducer to the
mounting surface. The BF Heat Flux Transducer should be mounted onto a good heat sink. Without a good heat sink, the energy impinging on the BF Heat
Flux Transducer cannot flow through the sensor and will instead just heat it up, resulting in erroneous measurements. The BF Heat Flux Transducer should also
be mounted so that there is minimal strain placed on the lead wires. This means that there should be no tension on the wires and there should be no direct
pressure on the sensors at the point where the leads are connected. Finally, when affixing the sensor in place, be careful not to touch the surface of the sensor
with bare fingers, as the resulting fingerprints may alter the emissivity of the sensor surface.

**ALL BF Sensors are individually calibrated to a NIST traceable standard**

Further Technical Information
BF sensor Installation (Manual)   MS-Word95(23KB)
Water Proofing BF sensors    MS-Word95(12KB)PDF(4KB)
BF sensor Measurement Tips        MS-Word95(67KB)PDF(18KB)
Maximum Heat Flux for the BF sensor      MS-Word95(20KB)PDF(6KB)