gas flow sensor GFL-9722 xensor integration bv smart sensor device s po box 3233 distributieweg 28 2601 de delft 2645 ej delfgauw the netherlands the netherlands phone +31 (0)15-2578040 founded 18 may 1988 fax +31 (0)15-2578050 trade reg. 27227437 email info@xensor.nl site www.xensor.nl abn-amro 60 50 40 311 iban nl42abna0605040311 vat nl 009122746 b01 copyright xensor integration 24 august 2005 page 1 of 3 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 gas flow sensor description the gas flow sensor GFL-9722 is a ceramic based thermal sensor. it consis ts of two thick-film heating resistors and a thick-film temperature sens or. both temperature sensor and heating resis- tors are laser trimmed which provides a true s ensor-to-sensor interchangeability. the sensitive parts of the sensor are coated with a black polym er, which protects them from harsh environments like aggressive solvents, corrosive gasses and aggressive vapors. when the GFL-9722 is heated by the heat ing resistors, a gas flow passing the sensor will cool it. because of this the output resistance will change. external temperature effects can be compensa- ted using a second, not-heated, sensor connec ted in a wheatstone bridge configuration. specifications (in air, ambient temperature 20 o c, 1 atm.) parameter typ units notes dimensions 7.5 x 7.5 mm operating temperature -40 to + 70 o c storage temperature -50 to + 170 o c heating resistor 50 1 ? typical heating voltage 7 v max. heating voltage 9 v temperature sensor 2000 10 ? stability < 0.5 % sensitivity 5.5 0.5 ? / o c time constant 3 sec. depending on flow and mounting
gas flow sensor GFL-9722 xensor integration bv smart sensor device s po box 3233 distributieweg 28 2601 de delft 2645 ej delfgauw the netherlands the netherlands phone +31 (0)15-2578040 founded 18 may 1988 fax +31 (0)15-2578050 trade reg. 27227437 email info@xensor.nl site www.xensor.nl abn-amro 60 50 40 311 iban nl42abna0605040311 vat nl 009122746 b01 copyright xensor integration 24 august 2005 page 2 of 3 dimensions 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). out heat 7.62 mm (0.3?) 10 mm 0.25 mm (0.1?) 0.25 mm (0.1?) 7.62 mm (0.3?) heat + out front front 0.5 mm 1.8 mm 12 3 flow direction a b tube 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, te mperature: 300 k, heating voltage: 7.00 v. flow velocity temp sensor (m/s) ( ? ) 0 2819 0.542 2625 1.051 2534 2.049 2455 3.099 2409 4.086 2379 5.010 2361 5.997 2343 7.089 2327 8.065 2317 9.052 2307 10.076 2292 2200 2400 2600 2800 01234567891011 flow velocity (m/s) ptc-resistance (ohm)
gas flow sensor GFL-9722 xensor integration bv smart sensor device s po box 3233 distributieweg 28 2601 de delft 2645 ej delfgauw the netherlands the netherlands phone +31 (0)15-2578040 founded 18 may 1988 fax +31 (0)15-2578050 trade reg. 27227437 email info@xensor.nl site www.xensor.nl abn-amro 60 50 40 311 iban nl42abna0605040311 vat nl 009122746 b01 copyright xensor integration 24 august 2005 page 3 of 3 application circuits: temperature compensation the following circuit can be used to compensate fo r temperature using the temperature reference chip td5 from honeywell. this circuit is driv en 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 ? at 20oc + 2750 ppm/k. GFL-9722 1 3 u sensor u comp us 7v 0v 11.3 k ? 4.99 k ? td5 sensor 50 heater ? temp sensor 123 application circuits: temperature compensation + read out the following circuit can be used to read out the sensor. GFL-9722 1 3 u sensor instr. amp. u comp us 7v 0v 11.3 k ? 4.99 k ? td5 sensor 50 heater ? temp sensor 123 conditions: use of sensors for i ndustrial applications is subjec ted 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 work manship 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 applicat ion or use of any product or circuit described or referenced herein.
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