GFL-9722

Gas flow sensor Features • Solid State reliability • Low cost, small size • Long-term stability (parts of a percent) • Interchangeability (0.5%) • Protective polymer coating • Custom designs on request Applications • Flow detection • Gas-flow measurements • Flow control • Absolute temperature measurement • Fluid detection GFL-9722 Gas flow sensor Description The Gas Flow Sensor GFL-9722 is a ceramic based thermal sensor. It consists of two thick-film heating resistors and a thick-film temperature sensor. Both temperature sensor and heating resistors are laser trimmed which provides a true sensor-to-sensor interchangeability. The sensitive parts of the sensor are coated with a black polymer, which protects them from harsh environments like aggressive solvents, corrosive gasses and aggressive vapors. When the GFL-9722 is heated by the heating resistors, a gas flow passing the sensor will cool it. Because of this the output resistance will change. External temperature effects can be compensated using a second, not-heated, sensor connected in a Wheatstone bridge configuration. Specifications (in air, ambient temperature 20 oC, 1 Atm.) Parameter Dimensions Operating temperature Storage temperature Heating resistor Typical heating voltage Max. heating voltage Temperature sensor Stability Sensitivity Time constant typ 7.5 x 7.5 -40 to + 70 -50 to + 170 50 ± 1 7 9 2000 ± 10 < 0.5 5.5 ± 0.5 3 units mm o C o C Ω V V Ω % Ω/ oC sec. notes depending on flow and mounting Xensor Integration bv copyright Xensor Integration 24 August 2005 Smart Sensor Devices PO Box 3233 Distributieweg 28 Phone +31 (0)15-2578040 Founded 18 May 1988 ABN-AMRO 60 50 40 311 2601 DE Delft 2645 EJ Delfgauw Fax +31 (0)15-2578050 Trade reg. 27227437 IBAN NL42ABNA0605040311 www.xensor.nl VAT NL 009122746 B01 The Netherlands The Netherlands Email info@xensor.nl Site page 1 of 3 Gas flow sensor Dimensions GFL-9722 Positioning the sensor The sensor is usually positioned parallel with the gas stream: • in the heart of the stream (a). • protuding from the wall of the tube (b). Front 7.62 mm (0.3”) 0.5 mm a tube b 7.62 mm (0.3”) Front 10 mm 0.25 mm (0.1”) Heat + Out Out 0.25 mm (0.1”) Heat 1.8 mm Flow direction 3 1 2 Example of resistence response vs flow Measurement in windtunnel by Mierij Meteo bv in de Bilt. GFL-9722 Sensor vertical parallel to flow, connections down. Pressure: 1024 mBar, temperature: 300 K, heating voltage: 7.00 V. Flow velocity (m/s) 0 0.542 1.051 2.049 3.099 4.086 5.010 5.997 7.089 8.065 9.052 10.076 Temp sensor (Ω) 2819 2625 2534 2455 2409 2379 2361 2343 2327 2317 2307 2292 ptc-resistance (Ohm) 2800 2600 2400 2200 0 1 2 3 4 5 6 7 8 9 10 11 flow velocity (m /s) Xensor Integration bv copyright Xensor Integration 24 August 2005 Smart Sensor Devices PO Box 3233 Distributieweg 28 Phone +31 (0)15-2578040 Founded 18 May 1988 ABN-AMRO 60 50 40 311 2601 DE Delft 2645 EJ Delfgauw Fax +31 (0)15-2578050 Trade reg. 27227437 IBAN NL42ABNA0605040311 www.xensor.nl VAT NL 009122746 B01 The Netherlands The Netherlands Email info@xensor.nl Site page 2 of 3 Gas flow sensor GFL-9722 Application circuits: Temperature compensation The following circuit can be used to compensate for temperature using the temperature reference chip TD5 from Honeywell. This circuit is driven by a constant voltage source and gives an analog output signal. NB: there is a DC-offset on the output signal which must be compensated out. The temp sensor is 2000 Ω at 20ºC + 2750 ppm/K. GFL-9722 Us 7V 4.99 kΩ 11.3 kΩ U sensor U comp 1 2 temp sensor 3 50Ω heater 1 TD5 sensor 3 0V Application circuits: Temperature compensation + read out The following circuit can be used to read out the sensor. GFL-9722 Us 7V 4.99 kΩ 11.3 U sensor kΩ 1 TD5 sensor 3 0V instr. amp. U comp 1 2 temp sensor 3 50Ω heater Conditions: Use of sensors for industrial applications is subjected to patent rights. Xensor Integration assumes no liability arising from violation of these rights Warranty: Xensor Integration warrants its products against defects in materials and workmanship for 12 months from date of shipment. Products not subject to misuse will be replaced or repaired. The foregoing is in lieu of all other expressed or implied warranties. Xensor Integration reserves the right to make changes to any product herein and assumes no liability arising out of the application or use of any product or circuit described or referenced herein. Xensor Integration bv copyright Xensor Integration 24 August 2005 Smart Sensor Devices PO Box 3233 Distributieweg 28 Phone +31 (0)15-2578040 Founded 18 May 1988 ABN-AMRO 60 50 40 311 2601 DE Delft 2645 EJ Delfgauw Fax +31 (0)15-2578050 Trade reg. 27227437 IBAN NL42ABNA0605040311 www.xensor.nl VAT NL 009122746 B01 The Netherlands The Netherlands Email info@xensor.nl Site page 3 of 3