CN202631024U - Self-calibration heat-precession vortex combined-type gas flow-rate measuring device - Google Patents
Self-calibration heat-precession vortex combined-type gas flow-rate measuring device Download PDFInfo
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- CN202631024U CN202631024U CN 201220223404 CN201220223404U CN202631024U CN 202631024 U CN202631024 U CN 202631024U CN 201220223404 CN201220223404 CN 201220223404 CN 201220223404 U CN201220223404 U CN 201220223404U CN 202631024 U CN202631024 U CN 202631024U
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Abstract
The utility model discloses a self-calibration heat-precession vortex combined-type gas flow-rate measuring device, which comprises a shell 1, a vortex generator 2, a heat-type speed sensor 3, a conversion and display unit 4 and a vortex eliminator 6, wherein an expansion section of the shell 1 is provided with a pressure sensor. The self-calibration heat-precession vortex combined-type gas flow-rate measuring device has the advantages of a heat-type flow-meter and the advantages of a precession vortex flow-meter, the measurement range is large, and a self-calibration function is realized.
Description
Technical field
The utility model relates to a kind of flow measurement device, a kind of specifically self-tuning hot type and precession vortex composition gas flow measurement device.
Background technology
In the prior art, thermal flowmeter is the flow instrumentation that utilizes the thermal diffusion principle design to form, and generally is used for the measurement gas mass rate.Thermal gas flowmeter is divided into immersion type, heat distribution type and boundary layer type.With the immersion type is the principle of work that example is explained thermal flowmeter.In pipeline, be provided with flow velocity probe and 1 temp probe of 1 heating element, take away heat when fluid flows through heating element.Ignore radiation and conductive force, the electric thermal power of electrons heat element equals the heat that unit interval inner fluid convection heat transfer is taken away, promptly
In the formula,
EFor acting on the heating voltage on the heating element,
RBe the resistance of heating element,
hBe surface coefficient of heat transfer,
Be flow velocity,
For heat transfer area,
T u Be the temperature of speed probe,
TIt is the fluid temperature (F.T.) that temp probe records.
According to heat transfer theory, surface coefficient of heat transfer is relevant with flow velocity and density:
In the formula,
a 0 ,
a 1 With n be the constant that experience is confirmed, ρ is a fluid density.
Can obtain flow velocity according to (1), (2)
Keep the temperature difference (
) or electric power
constant; Measure electric power
or (
), can obtain flow velocity.The temperature difference (
) or electric power
are constant according to keeping; Thermal flowmeter is divided into isothermal and the constant power type, and is wherein isothermal very fast to flow velocity reacting condition ratio.After recording flow velocity, can obtain flow according to velocity-area method.
Compare with turbo flow meter, vortex shedding flow meter, differential pressure flowmeter and volumeter etc.; It is little that thermal gas flowmeter has a crushing; Precision is high, and measurement range is big, no movable member and can measure plurality of advantages such as extremely hanging down flow velocity; And when being used to measure mass rate, need not temperature, pressure correction.On the other hand, thermal flowmeter also has some shortcomings, as: long-term heat aging of hot sensing head and dirty meeting produce thermal drift, influence measuring accuracy; Thermal flowmeter is a velocity flowmeter, and is longer to the requirement of front and back straight length, is generally preceding 10 backs 5.
Vortex precession flowmeter is to be the flowmeter that mechanism is processed according to vortex precession phenomenon.So-called vortex precession phenomenon is meant the eddy flow that receives constraint on every side when the pipeline that enlarges through the cross section, and the rotary middle spindle of eddy flow can be done precession.As shown in Figure 1, passed through spigot after, fluid forms bumpy flow, its center is " vortex core ", the periphery is a circulation.After bumpy flow is formed by a spigot,, obtain one section of short duration stablizing through throat through contraction section and throat's after-acceleration of one section likeness in form Venturi tube; The entering expansion segment is a significant slowdown; Pressure rises, and this moment, the pressure ratio ambient pressure in vortex core district was low, so produce local return; Vortex core off-center axle, the axis around flowmeter in expansion segment is done similar spiral helicine precession.The vortex precession frequency
fWith flow
q v Be directly proportional, promptly
In the formula;
is the vortex precession flowmeter instrument coefficient;
only with the instrument structure relating to parameters, and have nothing to do with composition with the physical property of fluid.
Vortex precession flowmeter and vortex shedding flow meter, fluidic flowmeter belong to vibratory flowmeter of the same type.Vortex precession flowmeter wide adaptability, upstream and downstream straight length require low, and be less demanding to medium, good stability, and no movable member is convenient to maintenance, thereby particularly has great advantage in corrosivity and the dirtier fluid metering at gas, liquid, steam.It seems that from a large amount of use enterprise feedacks main problem has in using vortex precession flowmeter: the setting of cutoff frequency has randomness; Comparatively responsive to undesired signals such as noise or vibrations; The pressure loss is bigger, is 4 ~ 5 times of vortex shedding flow meter crushing; Primary flow signal is faint, is restricted in the use.
The utility model content
The subject matter that the utility model will solve is to combine hot type and vortex precession flowmeter advantage separately, overcomes not enough separately.For this reason, the purpose of the utility model is to provide a kind of self-tuning hot type-precession vortex combined gas flow measurement device, comprises housing; Play spigot, hot type speed pickup, conversion and display unit; Despinner is equipped with pressure transducer on the expansion segment of said housing.
Described self-tuning hot type-precession vortex combined gas flow measurement device, said hot type speed pickup is arranged on the expansion segment of said housing.
Described self-tuning hot type-precession vortex combined gas flow measurement device, said hot type speed pickup have a speed probe and a temp probe.
Described self-tuning hot type-precession vortex combined gas flow measurement device also comprises signal processing module.
Described self-tuning hot type-precession vortex combined gas flow measurement device, said signal processing module comprises thermal flowmeter module and vortex precession flowmeter module.
The purpose of the utility model realizes based on following design:
1), adopt the high frequency sound thermal sensor to detect the flowing velocity signal for traditional vortex precession flowmeter structure.Institute's picked up signal adopts thermal flowmeter principle and vortex precession flowmeter principle to carry out Treatment Analysis respectively, and obtains data on flows separately.For the thermal sensor that is installed in the vortex precession flowmeter; It is detected to be to have the DC quantity Dynamic Signal; This signal averaging can be used for the thermal flowmeter Treatment Analysis and obtains flow, and pulsating quantity can be used for vortex precession flowmeter acquisition pulsed frequency and then obtains flow.
2) flow range is divided into three sections of low discharge, intermediate flow and big flows, by the heat type flow quantity signal as according to dividing flow section.In whole flow range, the thermal flowmeter data are adopted in flow output; In the intermediate flow scope, the vortex precession flowmeter data are used for comparing with the thermal flowmeter data, when the difference of the two numerical value surpasses regulation, the thermal flowmeter instrument coefficient are reset, and promptly proofread and correct.This way mainly is to utilize the characteristics of vortex precession flowmeter good stability, comes to revise at any time thermal sensor because the drift that a variety of causes causes guarantees the accuracy of measurement data during use.In addition, because the thermal sensor frequency response is not high, when big flow, possibly cause the vortex precession flowmeter cisco unity malfunction because precession frequency is too high, vortex precession flowmeter only is operated in the intermediate flow scope can reduce sensor frequency response parameter request.
3) the fluid-velocity survey module adopts isothermal mode of operation; Promptly keep the temperature difference (
) constant; Detect electric power
numerical value, obtain instantaneous velocity.The vortex precession flowmeter frequency of operation is generally 10Hz-1000Hz, and thermal sensor is difficult for accomplishing very high frequency sound, takes all factors into consideration, and the frequency response speed of hot type flow sensor and operating circuit thereof is not less than 300Hz.The frequency response of 300Hz is not difficult to accomplish for thermal sensor, is the operating frequency range in this method and select 100Hz-300Hz, can guarantee that the precession vortex flow measurement partly is operated in preferable states, and output data is reliable.
The beneficial effect that the utlity model has is:
1) keeps two kinds of flowmeters of hot type and precession vortex advantage separately, overcome shortcoming separately.Flowmeter rangeability based on this method is approaching with general thermal gas flowmeter, can reach more than the 1:100; This combined type flow-measuring method requires with conventional vortex precession flowmeter similar for the upstream and downstream straight length, general preceding 3 backs 1 get final product.
2) this combined type flow measurement hot type flow sensor, insensitive to undesired signals such as noise or vibrations, the instrument antijamming capability is strong; Simultaneously because this vortex precession flowmeter only is operated in intermediate flow; Cutoff frequency can be located at reasonable numerical value; Overcome traditional vortex precession flowmeter in the difficulty that is provided with aspect the cutoff frequency, eliminated " counting " problem that traditional vortex precession flowmeter low discharge " leaks meter " and causes with extraneous weak vibration or spurious signal more.
3) this combined type flow measurement device has self-correcting function; Promptly; The vortex precession flowmeter measurement data is accurate when intermediate flow; In this scope, with the vortex precession flowmeter data thermal flowmeter is proofreaied and correct at any time, can be reduced thermal gas flowmeter, prolong effective working life of flowmeter owing to the dirty measuring error that causes that signal drift causes of probe.
4) owing to vortex precession flowmeter module in this device only is operated in the partial discharge scope, play a spigot and play swirl effect requirement reduction, can design and play spigot than low pressure loss, reduce the pressure loss of whole flowmeter.
Description of drawings
Fig. 1 is a vortex precession flowmeter vortex precession synoptic diagram;
Fig. 2 is based on the intention of hot type-precession vortex combined gas flow apparatus;
Fig. 3 is hot type-precession vortex combined gas flow measurement device handling principle block diagram;
Fig. 4 is hot type-precession vortex combined gas flow measurement device NMO correction curve synoptic diagram;
Fig. 5 is that hot type-precession vortex combined gas flow measurement device calculates and automatic correcting process block diagram.
Each parts label among the figure: 1-housing; 2-plays spigot; 3-hot type speed pickup; 4-conversion and display unit; The 5-pressure transducer; The 6-despinner.
Embodiment
A kind of hot type of the utility model-precession vortex combined gas flow measurement device, as shown in Figure 2, this hot type-precession vortex combined gas flow measurement device comprises: housing 1; Play spigot 2; Hot type speed pickup 3, conversion and display unit 4, pressure transducer 5 and despinner 6.Pressure transducer 5 is installed on the expansion segment of said housing 1.Hot type speed pickup 3 is arranged on the expansion segment of said housing 1.
After fluid has passed through spigot 2, form bumpy flow, its center is " vortex core ", and the periphery is a circulation.Bumpy flow quickens through the contraction section of a piece housing 1, and in of short duration the stablizing of throat's acquisition of housing 1, the expansion segment flow velocity that gets into housing 1 reduces; Pressure rises; Vortex core off-center axle, the axis around flowmeter in expansion segment is done spiral helicine precession, and this vortex precession is flowed and is made near flow field velocity of expansion segment and pressure produce pulsation; The hot type speed pickup 3 that employing has high frequency sound detects dynamic speed signal; Comprised DC quantity in this signal, also comprised percent ripple, DC quantity and ripple frequency have all comprised flow information.In order to carry out the flow pressure correction, pressure transducer 5 has been installed.The signal of hot type speed pickup 3 and pressure transducer 5 is sent into conversion and display unit 4 carries out Treatment Analysis, obtains flow.Through despinner 6 rectifications, despinner 6 has and reduces the effect of downstream flow to the flowmeter work influence fluid simultaneously before flowing out flowmeter.
Signal processing module is as shown in Figure 3 in hot type-precession vortex combined gas flow measurement device.Contain two probes on the hot type speed pickup 3, one is speed probe, and one is temp probe, and temp probe is used for perception fluid temperature (F.T.) T, and isothermal pattern is adopted in velocity survey, i.e. the temperature of maintenance speed probe
T u With
TPoor (
) constant, detect electric power
Numerical value, wherein
EBe the heating voltage on the heating element that acts on the speed probe,
RResistance for heating element.With
, the fluid temperature signal of hot type flow sensor measures and the pressure signal that pressure transducer records all convert voltage signal into, after amplification filtering, modulus (A/D) conversion, sends into microprocessor.Wherein rate signal is sent into thermal flowmeter module and vortex precession flowmeter module simultaneously; Fluid temperature signal and pressure signal are sent into the vortex precession flowmeter module and are used for temperature, pressure correction; What thermal flowmeter was measured is mass rate, does not therefore need temperature, pressure correction.
Thermal flowmeter module and vortex precession flowmeter resume module, rate signal mean value that obtains respectively and vortex precession frequency signal are sent into flow rate calculation unit calculated flow rate.Two flow separatrix are set, Q
1And Q
2, according to these two flow separatrix flow range is divided into three sections of low discharge, intermediate flow and big flows, as shown in Figure 4.In whole flow range, the thermal flowmeter data are adopted in flow output; And in the intermediate flow scope; Vortex precession flowmeter data and thermal flowmeter data are sent into the instrument coefficient correcting unit and are compared; When the two numerical value differs above regulation, be that benchmark is revised and reset the thermal flowmeter instrument coefficient with the vortex precession flowmeter data.This way mainly is to utilize the characteristics of vortex precession flowmeter good stability, and it is long-term because the zero point drift that a variety of causes causes guarantees the accuracy of measurement data during use to revise at any time thermal sensor.The automatic correcting process block diagram of flow rate calculation and heat type flow quantity instrument coefficient is as shown in Figure 5.Heat type flow quantity data Q
HeatWith precession vortex data on flows Q
RevolveAfter sending into the flow rate calculation unit, according to Q
HeatJudge to be in which flow range,, then need carry out the correction work of thermal type flow measuring meter, relatively Q if be in the intermediate flow scope
HeatAnd Q
RevolveDifference with set maximum deviation
If deviation surpasses
, the thermal flowmeter instrument coefficient is revised and is reset.At last qualified flow rate calculation value being sent into display unit and data storage cell shows and stores.Simultaneously, convenient for data output, the instrument design of communication has communication interface, teletransmission driver, V/I transducer etc.
What need explanation is the Frequency Response about the hot type flow sensor.Tradition vortex precession flowmeter frequency of operation is generally 10Hz-1000Hz.Because the problem of thermal inertia, sensor must very tinyly could obtain high frequency sound, and very tiny sensor often damages easily; Take all factors into consideration; Selecting 100Hz-300Hz is the operating frequency range of this vortex precession flowmeter, and the frequency response of 300Hz is not difficult to accomplish for thermal sensor, and in this frequency range; The vortex precession flowmeter reliable operation, accuracy of measurement is high.
Shown in the above and the figure only is the preferred implementation of the utility model.Should be pointed out that for the person of ordinary skill of the art under the prerequisite of the principle that does not break away from the utility model, can also make some modification and improvement, these also should be regarded as belonging to the protection domain of the utility model.
Claims (4)
1. self-tuning hot type-precession vortex combined gas flow measurement device comprises:
Housing (1) plays spigot (2), hot type speed pickup (3), and conversion and display unit (4), despinner (6) is characterized in that: pressure transducer (5) is installed on the expansion segment of said housing (1).
2. self-tuning hot type as claimed in claim 1-precession vortex combined gas flow measurement device is characterized in that said hot type speed pickup (3) is arranged on the expansion segment of said housing (1).
3. self-tuning hot type as claimed in claim 1-precession vortex combined gas flow measurement device is characterized in that said hot type speed pickup (3) has a speed probe and a temp probe.
4. self-tuning hot type as claimed in claim 1-precession vortex combined gas flow measurement device is characterized in that also comprising signal processing module, and said signal processing module comprises thermal flowmeter module and vortex precession flowmeter module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220223404 CN202631024U (en) | 2012-05-18 | 2012-05-18 | Self-calibration heat-precession vortex combined-type gas flow-rate measuring device |
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|---|---|---|---|
| CN 201220223404 CN202631024U (en) | 2012-05-18 | 2012-05-18 | Self-calibration heat-precession vortex combined-type gas flow-rate measuring device |
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| Publication Number | Publication Date |
|---|---|
| CN202631024U true CN202631024U (en) | 2012-12-26 |
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|---|---|---|---|
| CN 201220223404 Expired - Fee Related CN202631024U (en) | 2012-05-18 | 2012-05-18 | Self-calibration heat-precession vortex combined-type gas flow-rate measuring device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105823714A (en) * | 2016-05-27 | 2016-08-03 | 武汉四方光电科技有限公司 | Wearable dust detection device and method |
-
2012
- 2012-05-18 CN CN 201220223404 patent/CN202631024U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105823714A (en) * | 2016-05-27 | 2016-08-03 | 武汉四方光电科技有限公司 | Wearable dust detection device and method |
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|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20121226 Termination date: 20130518 |