CN109839161A - MEMS thermal mass gas meter apparatus and measuring gas flow rate method - Google Patents
MEMS thermal mass gas meter apparatus and measuring gas flow rate method Download PDFInfo
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- CN109839161A CN109839161A CN201711195866.2A CN201711195866A CN109839161A CN 109839161 A CN109839161 A CN 109839161A CN 201711195866 A CN201711195866 A CN 201711195866A CN 109839161 A CN109839161 A CN 109839161A
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Abstract
A kind of MEMS thermal mass gas meter apparatus and measuring gas flow rate method, MEMS thermal mass gas meter apparatus are on the gas flow surveying instrument table body equipped with temperature sensor and energy converter and to connect shunt valve, MEMS flow sensor are housed on shunt valve；Temperature sensor, energy converter and MEMS flow sensor are all connected with data processor.Measuring method with above-mentioned apparatus gas flow is: the detection of 1 gas instantaneous flow；The measurement of 2 gas conversion coefficients；The amendment of 3 gas instantaneous flows, the gas flow measured.The present invention is by ultrasonic acoustic speed measuring device in conjunction with MEMS flow sensor, extend the scope of application, combustion gas and various industrial gasses can be measured, in data processing, the variation of ultrasonic acoustic speed measuring device real-time monitoring gas component, it calculates gas conversion coefficient to compensate instantaneous flow, improves the measurement accuracy of gas flow, the application and popularization to heat type gas flow instrument have broad sense.
Description
Technical field
The present invention relates to gas flow measurement fields, more particularly, to a kind of thermal mass gas meter apparatus and gas flow
Measuring method.
Background technique
It is well known that corresponding test device is also varied now to measure there are many kinds of the methods of gas flow,
But the limitation that every kind of device has it to test, for example heat type gas flow measuring device, principle are gas flow rate and gas
Molecule takes away the relationship between heat.The size of the component of gas and specific heat capacity at constant pressure in this way can all influence the accuracy of measurement.
Such as current thermal type flow measuring apparatus, it is substantially and is provided in gas metering according to scene with air or nitrogen calibration
Gas Components, calculate gas conversion coefficient and compensate, if but Gas Components change flow measurement in use
Deviation will be will appear.
Publication date is on March 30th, 2011, the patent document of Publication No. CN 101126652B discloses electronic type quality
Flow gas gauge table, gas meter housing are the shell with air-tightness cavity, and the intracorporal appendix of shell is divided into independent air inlet
Pipe, and the flow detection pipe and escape pipe that link together, air inlet, escape pipe are connect with the inlet, outlet interface of shell respectively,
The downstream of flow detection pipe is connect with escape pipe and level is hanging in the housing, and flow detection pipe has mainstream air flue and bypass
Air flue, setting one is located between the two through hole of connection bypass air flue for the device of shunting in mainstream air flue, bypasses cutting for air flue
Area is less than the sectional area of mainstream air flue, and the sensing module of a thermal type mass flow sensor is set to the bypass for detection
The inner wall of air flue.It can carry out mass flow metering to the combustion gas of process, and the dust contained in combustion gas can be prevented attached
On sensing element, improve combustion gas using metering accuracy and gas meter, flow meter service life.Above-mentioned apparatus can realize combustion gas
Mass flow measurement, be not necessarily to Temperature and Pressure Correction.Whether there is or not movable member, response are fast, high-precision for MEMS thermal mass gas meter
The features such as degree, super-wide range, ultralow initial-flow, low pressure loss.But the device is demarcated using air, fixed gas turns
Coefficient is changed, does not have real-time compensation function when Gas Components variation, affects the authenticity of metering.
Publication date is on July 11st, 2012, and the patent document of Publication No. CN102564516A discloses a kind of electronics combustion
Gas meter, including gas mass flow rate sensors, signal conditioning circuit, A/D converter, microprocessor, LCD MODULE, gas
Sensor, temperature and pressure sensor and gas data storehouse memorizer, realize to multicomponent gas in different temperatures, pressure strip
The measurement of volume flow under part.Above-mentioned apparatus only identifies gas composition, is converted to volume flow to mass flow
Density revision is carried out, does not do the conversion coefficient amendment of gas, while the device is in practical applications, gas flow rate passes gas
The influence of sensor is also difficult to completely eliminate, and influences the precision of flow detection.
Summary of the invention
Current heat type gas flow measuring device there are aiming at the problem that, a kind of measurement accuracy height, good reliability, tool are provided
There are the flow measurement device and gas flow measurement method of automatic identification gas conversion coefficient.
The present invention is used by reaching above-mentioned technical purpose the specific technical proposal is: a kind of MEMS thermal mass gas meter, flow meter
Device and measuring gas flow rate method, MEMS thermal mass gas meter apparatus, including temperature sensor, ultrasonic transducer and
Data processor, it is characterized in that: MEMS thermal mass gas meter apparatus: be equipped with temperature sensor 4 and transmitting transducer 1 and
It receives on the gas flow surveying instrument table body 11 of energy converter 10 and connects shunt valve 5, the import 9 of shunt valve 5 is located at bluff body 2
Air-flow upstream side, the outlet 3 of shunt valve are located at the airflow downstream side of bluff body 2, MEMS flow sensor 6 are housed on shunt valve 5；
Temperature sensor 4, transmitting transducer 1 and reception energy converter 10 and MEMS flow sensor 6 on gas flow surveying instrument is equal
Data processor 7 is connected, data processor 7 connects data presentation device 8.
Measuring method with above-mentioned apparatus gas flow is:
The detection of 1 gas instantaneous flow: when gas is flowed in from 11 entrance of table body to outlet by bluff body 2, a part
Gas is flowed into shunt valve 5 by shunt valve import 9, then from 3 outflow of shunt valve outlet, when flowing through MEMS flow sensor 6
Flow signal is generated, gas instantaneous flow is measured；
The measurement of 2 gas conversion coefficients: when gas flowing, transmitting transducer 1 emits ultrasonic wave, the reception transducing on opposite
Device 10 receives ultrasonic wave, measures and emits and receive the time of ultrasonic wave in 11 bore x stroke of table body, calculates ultrasonic wave
The velocity of sound in table body 11 in gas, temperature sensor 4 measure temperature at this time, pass through temperature-compensating, data processor meter
The velocity of sound for calculating gas under normal temperature inquires corresponding gas conversion coefficient in memory by the velocity of sound；
The amendment of 3 gas instantaneous flows: the gas of the flow calibration of present apparatus gas instantaneous flow value is air, by air
Gas conversion coefficient be set as 1, when measuring combustion gas or when other gases, then need by gas conversion coefficient that gas is instantaneous
Flow value amendment, thus the gas flow measured.This variation according to gas component, in real time to gas conversion coefficient into
The automatic modified method of row, is in the program operational process of flow measurement while to carry out, and process is: device powers on, and closes
Simultaneously system clock frequency is arranged in WatchDog Timer, and then flush events array, is initialized to the port of MCU；Setting is seen
The time of door dog timer and basic timer is respectively 1 second and 16 milliseconds and opens interrupters；When there is interrupt response, system
The event routine of response is executed, when not having interrupt response, system then enters low-power consumption mode；External storage is initialized,
MCU is set to read operating status and system parameter from external storage；First to MEMS module initialization, then MEMS module
Flow signal is acquired, calculates instantaneous flow value according to nominal data；In timer interruption, ultrasonic wave module and temperature are passed
Sensor is initialized, and is made ultrasonic wave module acquisition time and is calculated the velocity of sound, temperature sensor measures real time temperature, and to sound
Speed carries out temperature-compensating, and MCU searches the gas conversion coefficient of the corresponding velocity of sound in Flash, is modified to gas instantaneous flow value
Afterwards, volume computation output display.
Beneficial effects of the present invention:
By the measuring method of gas meter, flow meter metering device and gas conversion coefficient provided by the present invention, heating type gas is improved
Authenticity, the accuracy and reliability of measurement method organically combine ultrasonic acoustic speed measuring device and MEMS flow sensor,
The scope of application of heat type gas flow measuring device is extended, combustion gas and various industrial gasses can be measured, and number
In data processing according to processing system, the variation of ultrasonic acoustic speed measuring device real-time monitoring gas component calculates gas
Conversion coefficient compensates instantaneous flow, so that the measurement accuracy of gas flow is also improved, to heat type gas flow instrument
There is broad sense in the application and popularization of gas burning field.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of MEMS thermal mass gas meter apparatus of the present invention.
Fig. 2 is the program circuit schematic diagram of the measuring method of gas flow of the present invention
In Fig. 1: 1. transmitting transducers, 2. bluff bodys, the outlet of 3. shunt valves, 4. temperature sensors, 5. shunt valves,
6.MEMS flow sensor, 7. data processors, 8. data presentation devices, the import of 9. shunt valves, 10. reception energy converters, 11.
Table body.
Specific embodiment
The specific embodiment of technical solution of the present invention is made further below by way of examples and with reference to the accompanying drawings
It is bright.
Embodiment 1: a kind of MEMS thermal mass gas meter apparatus and measuring gas flow rate method, the combustion of MEMS thermal mass
Gas meter device, as shown in Figure 1, its connection relationship is: band (the dallas, U.S.A model of temperature sensor 4 on table body 11
DS18B20) with transmitting transducer 1 (model GB-117CS1A, Panasonic Japan) and reception energy converter 10 gas flow measurement
On device and shunt valve 5 is connect, the diameter of shunt valve 5 is 3mm, and two ultrasonic transducers can emit and receive ultrasonic wave, is surpassed
The frequency of sonic transducer transmitting and received ultrasonic wave is 500KHz.The import 9 of shunt valve 5 is located at the air-flow upstream of bluff body 2
Side, the outlet 3 of shunt valve are located at the airflow downstream side of bluff body 2, and the pressure difference of the generation of bluff body 2 is flowed through using table body gas, is made
Shunt valve gas flows through MEMS flow sensor 6 (model FMA1100R-001, Meixin Semi-conductor (Wuxi) Co. Ltd.) table
Face carries out instantaneous flow measurement.Temperature sensor 4, transmitting transducer 1 and reception energy converter 10 on gas flow surveying instrument
And MEMS flow sensor 6 is all connected with data processor 7 (TI Texas Instrument), data processor 7 is provided with by well known calculating
The data processing software of formula conversion, data processor 7 connect data presentation device 8.
Measuring method using above-mentioned apparatus gas flow is:
1 gas instantaneous flow detection: when gas is flowed in from entrance to exit list body 11 by bluff body 2, in choked flow
2 two sides of body generate pressure difference, so that a part of gas is flowed into shunt valve 5 by shunt valve import 9, then flow from shunt valve outlet 3
Out, flow signal is generated when gas flows through 6 surface of MEMS flow sensor, measures gas flow；
The measurement of 2 gas conversion coefficients: transmitting transducer 1 emits ultrasonic wave, and the reception energy converter 10 on opposite receives super
Sound wave, measurement emit and receive the time of ultrasonic wave in 11 bore x stroke of table body, calculate ultrasonic wave gas in table body 11
In the velocity of sound, temperature sensor 4 measures temperature at this time, and by temperature-compensating, data processing equipment calculates gas standard
At a temperature of the velocity of sound, gas conversion coefficient and velocity of sound corresponding relation database are inquired by the velocity of sound, obtain the reality of the gas
Conversion coefficient.
The amendment of the first measured value of 3 gas flows: the gas of the flow calibration of present apparatus gas instantaneous flow is air, is being measured
It does not need to be modified measured value when air mass flow, the specific heat capacity at constant pressure of air is set as 1, when measurement combustion gas or other gas
When body, then need to correct measured value at the beginning of gas flow by gas conversion coefficient, this variation according to gas component, it is right in real time
The method that gas conversion coefficient is automatically corrected is in the program operational process of flow measurement while to carry out, and process is such as
Shown in Fig. 2, be: device powers on, and closes WatchDog Timer and system clock frequency is arranged, then flush events array, give MCU
Port initialized；The time that WatchDog Timer and basic timer is arranged is respectively 1 second and 16 milliseconds and opens
It interrupts；When there is interrupt response, system executes the event routine of response, and when not having interrupt response, system then enters low-power consumption
Mode；External storage is initialized, MCU is allow to read operating status and system parameter from external storage；It is right first
MEMS module initialization, then MEMS module acquires flow signal, calculates instantaneous flow according to nominal data；In timer
In disconnected, ultrasonic wave module and temperature sensor are initialized, makes ultrasonic wave module acquisition time and calculates the velocity of sound, temperature
Sensor measures real time temperature, and carries out temperature-compensating to the velocity of sound, and MCU searches the gas conversion coefficient of the corresponding velocity of sound in Flash,
After being modified to gas instantaneous flow, volume computation output display.
Claims (3)
1. a kind of MEMS thermal mass gas meter apparatus, including temperature sensor, ultrasonic transducer and data processor, special
Sign is: MEMS thermal mass gas meter apparatus: being equipped with temperature sensor 4 and transmitting transducer 1 and reception energy converter 10
On gas flow surveying instrument table body 11 and shunt valve 5 is connect, the import 9 of shunt valve 5 is located at the air-flow upstream side of bluff body 2, other
The outlet 3 of road pipe is located at the airflow downstream side of bluff body 2, and MEMS flow sensor 6 is housed on shunt valve 5；Gas flow measurement
Temperature sensor 4, transmitting transducer 1 and reception energy converter 10 and MEMS flow sensor 6 on device are all connected with data processing
Device 7, data processor 7 connect data presentation device 8.
2. the measuring method of the gas flow using claim 1 described device, it is characterized in that:
The detection of gas instantaneous flow: when gas is flowed in from 11 entrance of table body to outlet by bluff body 2, a part of gas is logical
It crosses shunt valve import 9 to flow into shunt valve 5, then from 3 outflow of shunt valve outlet, stream is generated when flowing through MEMS flow sensor 6
Signal is measured, gas instantaneous flow is measured；
The measurement of gas conversion coefficient: when gas flowing, transmitting transducer 1 emits ultrasonic wave, the reception energy converter 10 on opposite
Ultrasonic wave is received, measures and emits and receive the time of ultrasonic wave in 11 bore x stroke of table body, calculate ultrasonic wave in table
The velocity of sound in body 11 in gas, temperature sensor 4 measure temperature at this time, and by temperature-compensating, data processor is calculated
The velocity of sound of gas under normal temperature inquires corresponding gas conversion coefficient in memory by the velocity of sound；
The amendment of gas instantaneous flow: the gas of the flow calibration of present apparatus gas instantaneous flow value is air, by the gas of air
Body conversion coefficient is set as 1, when measuring combustion gas or when other gases, then needs gas instantaneous flow through gas conversion coefficient
Value amendment, thus the gas flow measured.
3. this variation according to gas component, the method being automatically corrected in real time to gas conversion coefficient are surveyed in flow
It is carried out simultaneously in the program operational process of amount, process is: device powers on, and closes WatchDog Timer and system clock frequency is arranged
Rate, then flush events array, is initialized to the port of MCU；The time of WatchDog Timer and basic timer is set
Respectively 1 second and 16 milliseconds and opens interrupters, when there is interrupt response, system executes the event routine of response, without in
When disconnected response, system then enters low-power consumption mode；External storage is initialized, MCU is read from external storage and transports
Row state and system parameter；First to MEMS module initialization, then MEMS module acquires flow signal, according to nominal data meter
Calculate instantaneous flow value；In timer interruption, ultrasonic wave module and temperature sensor are initialized, make ultrasonic wave module
Acquisition time simultaneously calculates the velocity of sound, and temperature sensor measures real time temperature, and carries out temperature-compensating to the velocity of sound, and MCU is looked into Flash
The gas conversion coefficient for looking for the corresponding velocity of sound, after being modified to gas instantaneous flow value, volume computation output display.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201711195866.2A CN109839161A (en) | 2017-11-24 | 2017-11-24 | MEMS thermal mass gas meter apparatus and measuring gas flow rate method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711195866.2A CN109839161A (en) | 2017-11-24 | 2017-11-24 | MEMS thermal mass gas meter apparatus and measuring gas flow rate method |
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| CN109839161A true CN109839161A (en) | 2019-06-04 |
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| CN201711195866.2A Pending CN109839161A (en) | 2017-11-24 | 2017-11-24 | MEMS thermal mass gas meter apparatus and measuring gas flow rate method |
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