Air Mass Flow Sensor

No offset, offset drift or interference from power supply No require thin membrane or surface cavity liquid flow measurement

Air Mass Flow consists of two thermopiles and a heating resistance, thermopiles symmetrically distributed upstream and downstream of heating resistance. The hot junctions of the thermopiles and the heating resistance on a thermal isolation base, generates an output voltage proportional from temperature gradient that between its hot and cold junctions, that is self energy Seebeck effect.

Applications

-           air mass flow in HVAC and Automotive application

-           Medical respirators and ventilators

-           Gas analyzer

-           Gas Calibration

Performance

-           Sensitive extremely for low rates and micro-differential pressure

-           No offset and offset drift 

-           Fast response (Less than 10ms)

-           Resistant to corrosive gases and attrition

-           Resistant to vibration and high pressure( more 15 atmosphere pressure)

-           Simplified signal conditioning circuits

Advantage

-           The thermopile generates voltage output without biasing. As a result, there is no offset, offset drift or interference from power supply.

-           The unique thermal isolation design does not require thin membrane or surface cavity. As a result, the die can withstand pressure shock, and can be coated with ceramic film that protect it from corrosive gases/liquids and abrasive wear.

-           The sensor to be used for liquid flow measurement

Performance Specifications

Parameter	Min.		Typical		Max.		Unit
Full Scale			1000				sccm
Zero Drift			±0.1				mv
Output Voltage Drift		±1					%F.S
Repeatability/Hysteresis		1					%F.S
Heating Current	6, (constant current)						mA
Heating Power	95, (constant power)						mW
Heating Resistance	2570		2690		2810		ohm
Zero Thermal Drift			0.8			%FS
Reference Resistor TCR			-578			Ppm/C
UpstreamThermopile Output (Air,25C)	149		165	171		mV
Downstream Thermopile Output (Air,25C)	149		165	171		mV
Operating Temperature	-10			80		C
Response Time	Less than 10					ms
Overpressure	More than 15(217)					Bar(psi)

Air Mass Flow Sensor