CN202420590U

CN202420590U - Electronic gas meter

Info

Publication number: CN202420590U
Application number: CN2012200178640U
Authority: CN
Inventors: 张旭辉; 徐爱东; 杨拥军
Original assignee: MT MICROSYSTEMS CO Ltd
Current assignee: MT MICROSYSTEMS CO Ltd
Priority date: 2012-01-16
Filing date: 2012-01-16
Publication date: 2012-09-05
Anticipated expiration: 2022-01-16

Abstract

The utility model discloses an electronic gas meter, comprising a gas mass flow sensor, a signal conditioning circuit, an A/D (Analogue/Digital) converter, a microprocessor, a liquid crystal display module, a gas sensor, a temperature-pressure sensor and a gas database memorizer, wherein the gas mass flow sensor is connected with the input end of the signal conditioning circuit; the output end of the signal conditioning circuit is connected with the input end of the microprocessor via the A/D converter; the output end of the microprocessor is connected with the liquid crystal display module; the gas sensor and the temperature-pressure sensor are respectively connected with corresponding input ends of the signal conditioning circuit, and the microprocessor is connected with the gas database memorizer. The electronic gas meter has the beneficial effects that the accurate measurement of the volume flow rate of the multi-component gas under different temperatures and pressure conditions is realized, and measurement error is reduced.

Description

The electronic gas table

Technical field

The utility model relates to the gas flow measurement Instrument technology field.

Background technology

At present; The domestic gas meter of widespread use comprises common mechanical character wheel formula gas meter, flow meter and electronic type diaphragm gas meter (comprising IC-card table, remote installed meter etc.); These gas meter, flow meters all adopt the epithelium formula gas meter, flow meter base table of mechanical drive metered volume flow, and its parts are very many, complicated in mechanical structure; Manufacturing, processing and assembly technology difficulty are big, and manufacturing cost is higher relatively; Because physical construction certainly exists the limitation of intrinsic friction, make the traditional mechanical gas meter, flow meter insensitive to the tiny flow quantity reaction, influenced the precision of measuring.Traditional mechanical gas meter, flow meter volume is bigger, and is compatible relatively poor, brings inconvenience for the installation and the measurement of user and gas company; Because phenomenons such as the wearing and tearing of the intrinsic existence of movable mechanical structure, pollutions, it is accurate or malfunctioning to cause movable member to lose with the increase appearance action of service time, brings measuring error.Diaphragm gas meter is easily artificial to be blocked mechanical motion and steals gas, and based on the electronic gas table of membrane type base table, it is subject to the interference of various factors by machinery to electric conversion process, causes error in dipping or mistake.

More existing electronic type diaphragm gas meters; Through integrated temperature sensor or while integrated temperature and pressure transducer; The epithelium formula base table flow signal of electronization is carried out temperature or temperature/pressure compensation; Its process more complicated, cost is high, and can't avoid the intrinsic shortcoming of aforementioned epithelium formula base table.

Other gas meter, flow meter electronization scheme also has ultrasonic technique and thermal mass flow meter technology.Ultrasonic technique still adopts volumetric flow rate metering principle, and cost is high, detects the technological the same of principle with all based on volumetric flow rate, realizes that accurate measurement need compare compensation such as complicated temperature, pressure, needs to increase extra hardware; What traditional thermal mass flow meter was measured is mass rate, need not compensation such as temperature, pressure and can obtain very high measuring accuracy, but cost is high, and power consumption is big, and consistance is relatively poor.Though this also just epithelium formula gas meter, flow meter technology have various shortcoming but still in existing market, occupy the dominant position reason.

Thermal type gas quality flow meter is as a kind of new gas flow instrumentation, have low in energy consumption, highly sensitive, crushing is low, flow range is big, precision is high, no movable member can realize that low discharge measures, need not advantages such as temperature pressure compensation.Yet what thermal type gas quality flow meter was measured is mass rate, and is standard measure of quantity with the volumetric flow rate in the existing gas metering national standard, has therefore limited the application of thermal type gas quality flow meter.A kind of simple way be mass rate that thermal type gas quality flow meter is obtained divided by a fixing coefficient (being density), mass rate is converted into volumetric flow rate; But when gas temperature, pressure change greatly, especially when gas be polycomponent, and under the component ratio situation about changing often again, its density has very big-difference, so the volumetric flow rate that adopts this method to obtain will have very large error.

The utility model content

The utility model technical matters to be solved provides a kind of electronic gas table that can realize the multicomponent gas under different temperatures, the pressure is carried out volume flow measurement, and its degree of accuracy is high, volume is little, easy to use, cost is low.

For solving the problems of the technologies described above; The technical scheme that the utility model is taked is: a kind of electronic gas table; Comprise gas mass flow quantity sensor, signal conditioning circuit, A/D converter, microprocessor, LCD MODULE, gas sensor, temperature and pressure sensor and gas data storehouse memorizer; Said gas mass flow quantity sensor is connected with the input end of signal conditioning circuit; The output terminal of said signal conditioning circuit is connected with the input end of microprocessor through A/D converter, and the output terminal of said microprocessor is connected with LCD MODULE; Said gas sensor is connected with the respective input of said signal conditioning circuit respectively with the temperature and pressure sensor, and said microprocessor is connected with the gas data storehouse memorizer.

Said gas sensor is a kind of in the following sensor: spectral type gas sensor, thermal conductance type gas sensor, electrochemical gas sensor or semi-conductor type gas sensor; The concrete model of spectral type gas sensor is IRNET-P-20-CH4-L-EX-VS-2-N; The concrete model of thermal conductance type gas sensor is NAP-21A; The concrete model of electrochemical gas sensor is NAP-55A, and the concrete model of semi-conductor type gas sensor is CGS12.

The above-mentioned gas mass flow sensor is a hot diaphragm type gas mass flow quantity sensor, and its model is AFS01; The model of temperature and pressure sensor is PS01; The model of said LCD MODULE is LCM141C; The model of said gas data storehouse memorizer is FM24CL64.

It is that the instrument amplifier of AD627 is as the low-power consumption pre-amplifier that signal conditioning circuit adopts model; The A/D converter model is ADS1230; The gas mass flow that is recorded by the gas mass flow quantity sensor, the gas composition that is recorded by gas sensor and information such as the gas temperature that is recorded by the temperature and pressure sensor and pressure are the analog switch input a/d converter of ADG849 through model; Input microprocessor then, the model of said microprocessor adopts MSP430F147.

Adopt the beneficial effect that technique scheme produced to be: through gas mass flow sensor acquisition gas mass flow information; Gather gas componant, composition information through gas sensor; Temperature, pressure information through temperature and pressure sensor acquisition gas; These information are through signal conditioning circuit and A/D converter input microprocessor; Every kind of gas density of storing in the microprocessor combination gas data storehouse memorizer calculates the equivalent density of tested gas with the variation relation of temperature, pressure, and then mass rate accurately is converted into volumetric flow rate in real time.Its degree of accuracy is high, volume is little, easy to use, cost is low.Can realize the accurate measurement of multicomponent gas, reduce measuring error, reach the measurement standard of country combustion gas.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is done further detailed explanation.

Fig. 1 is the theory diagram of the utility model.

Embodiment

Concrete implementation of the present invention and principle are following:

Utilize the gas mass flow quantity sensor to record the mass rate of gas to be measured; Utilize gas sensor accurately to record the shared number percent of various composition gases in gas composition and the gas; Utilize the temperature and pressure sensor to record temperature, the pressure information of gas, these information are through signal conditioning circuit, A/D converter input microprocessor; Microprocessor calls the information that all kinds of gas densities in the gas data storehouse memorizer change with temperature, pressure; Combine gas composition information simultaneously, calculate the density of multicomponent gas to be measured, combine the mass rate information of the gas to be measured that the gas mass flow quantity sensor records then; Calculate the volumetric flow rate of gas to be measured; Measurement result is accurate, can Yin Wendu, the variation of pressure causes the test result error, is applicable to the measurement of the volumetric flow rate of various multicomponent gases.

Computation process is following:

If gaseous mass is ; Gas density is

, and gas volume is

then arranged

Gas density is difference with the difference of gaseous species, temperature

, pressure

etc.; Gas for particular types; Under household condition; Its density can be described with the imperial equation of carat uncle with the relation of temperature, pressure; I.e. then has .

For mixed gas (

;

;

); Comprise component A, B ... Its shared volume fraction is respectively

,

..., following equation is arranged:

?

……

Then have:

Further have:

Then have:

Can record mass rate

value of gas to be measured through the gas mass flow quantity sensor; Temperature, force value (

,

) through the temperature and pressure sensor records obtain gas composition (A, B through gas sensor ... Deng) and volumn concentration (

,

of each component gas ... Deng).

Microprocessor obtains gas composition A, B through inquiry gas data storehouse memorizer ... Etc. corresponding molecular weight ( ,

... Deng) and

; Can calculate the real-time density of mark condition

of gas to be measured; And then obtaining the mark condition volumetric flow rate of gas to be measured, this value is equivalent to through excess temperature, volumetric flow rate that pressure compensated diaphragm gas meter is surveyed.

... Deng) and

; The temperature, the force value ( ,

) that record in conjunction with the temperature and pressure sensor; Can calculate the real-time density

of gas to be measured; And then obtaining the operating mode volumetric flow rate

of gas to be measured, this value is equivalent to without excess temperature, volumetric flow rate that pressure compensated diaphragm gas meter is surveyed.

Claims

1. electronic gas table; Comprise gas mass flow quantity sensor, signal conditioning circuit, A/D converter, microprocessor and LCD MODULE; Said gas mass flow quantity sensor is connected with the input end of signal conditioning circuit; The output terminal of said signal conditioning circuit is connected with the input end of microprocessor through A/D converter; The output terminal of said microprocessor is connected with LCD MODULE, it is characterized in that, also comprises gas sensor, temperature and pressure sensor and gas data storehouse memorizer; Said gas sensor is connected with the respective input of said signal conditioning circuit respectively with the temperature and pressure sensor, and said microprocessor is connected with the gas data storehouse memorizer.

2. electronic gas table according to claim 1 is characterized in that, said gas sensor is a kind of in the following sensor: spectral type gas sensor, thermal conductance type gas sensor, electrochemical gas sensor or semi-conductor type gas sensor.