CN1053493A - Mass flowmeter - Google Patents
Mass flowmeter Download PDFInfo
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- CN1053493A CN1053493A CN 91100796 CN91100796A CN1053493A CN 1053493 A CN1053493 A CN 1053493A CN 91100796 CN91100796 CN 91100796 CN 91100796 A CN91100796 A CN 91100796A CN 1053493 A CN1053493 A CN 1053493A
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- pressure
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Abstract
The present invention relates to a kind of driect type mass flowmeter, comprising: composite signal generation body, detecting element and specialized circuitry.Composite signal generation physical efficiency produces pressure difference signal, can produce strong stable whirlpool simultaneously again, its frequency through one with the detecting element that body is separated takes place receives and spread out of.Pressure difference signal and frequency signal are handled through specialized circuitry and are obtained output signals such as mass rate, volumetric flow rate, density.This flowmeter is not subjected to the influence of factors such as fluid temperature (F.T.), pressure, component, density, can measure the mass rate of liquid, gas (comprising: become component liquid, gas) effectively, good stability, and crushing is little, and energy consumption is little, measures accurately, makes easy for installation.
Description
The present invention relates to a kind of driect type mass flowmeter of carrying out mass rate mensuration by measuring fluid pressure difference and whirlpool frequency.
Application at present mass flowmeter great majority more widely is coriolis mass flowmeters, and it is according to the Coriolis principle design, and common form is a U type tubular type.This flowmeter survey liquid quality flow can obtain satisfied effect, but structure is complicated, be subjected to measuring the restriction of caliber, be unsuitable for flow measurement than bassoon footpath fluid, crushing is bigger, particularly it is unsuitable for gas, and particularly the mensuration of the mass rate of low-pressure gas is restricted its range of application.Another kind is used for the calorimetric mass-flow gas meter of measurement gas mass rate, under need the situation of constant at medium specific heat (being that gas composition is fixed), could accurately record its quality, the mensuration that therefore becomes the component gas mass rate is to need a difficult problem solving in the fluid flux measurement technology.
The disclosed a kind of mass flowmeter of the clear 62-140025 of Japan is different from above-mentioned two kinds of flowmeter principles, and cycle and fluid that it utilizes eddy generator to produce whirlpool come the quality measurement flow through the pressure loss that the body front and back take place.Fig. 5 is the schematic diagram of this invention.
As shown in Figure 5: an eddy generator 22 is set in pipeline 16, measures pressure reduction △ P between the negative pressure that pressure before the eddy generators and eddy generator produced the whirlpool center by first connecting pipe 17 on the tube wall and second connecting pipe 20
1, there is following relation between it and density and the flow velocity:
△P
1∝Cp 1/2 ρV
2<1>
Cp-pressure loss coefficient in the formula
The v-fluid velocity
ρ-fluid density
Draw from eddy generator back tube wall again and measure pressure reduction △ P between the 3rd connecting pipe 21 and second connecting pipe
2, pressure reduction △ P
2The whirlpool frequency f that rate of change and eddy generator produced proportional:
f∝St (v)/(d)
In the formula: the S-Strouhal number
D-eddy generator fluoran stream surface width
The V-rate of flow of fluid
F-whirlpool frequency
Obvious △ P
1/ f ∝ ρ v(ρ v is a mass rate)
This flowmeter is different from the first two from principle and plants quality flowmeter, but owing to utilized eddy generator to measure indirectly on technical scheme only singlely, so can there are the following problems in the practical application:
A. utilize pressure reduction △ P
2Variation represent the whirlpool frequency f
1The disturbing factor that is subjected to is more, particularly when low discharge and gas flow, pass through △ P
2Ten fens difficulties of measured frequency f.
B. since directly from the eddy generator the pressure difference signal have any problem, so should invention from the tube wall pressure, this method output pressure reduction is little, and is subjected to the power of whirlpool and stability influence bigger, pressure difference signal has pulsation.The accuracy that influence is measured.So this flowmeter will directly record mass rate accurately, the mass rate that particularly becomes component gas still need be advanced an improvement.
The objective of the invention is to provide a kind of mass flowmeter that utilizes itself both can directly record stable and bigger pressure differential signal, can produce stable, strong whirlpool again and survey its frequency, and then obtain the driect type mass flowmeter of the mass rate of various fluids (comprise and become component flow).
Fig. 1 is the structural principle synoptic diagram of this flowmeter;
Fig. 2 is a composite signal generation body A-A cross-sectional view in this flowmeter;
Fig. 3 is this flowmeter change-over circuit schematic diagram;
Fig. 4 is the structural representation when in the pressure guide hole of composite signal generation body of this flowmeter piezoelectric sensor being housed;
Fig. 6 A, Fig. 6 B are that this flowmeter carries out liquid experiment operation result curve map;
Fig. 7 A, Fig. 7 B are that this flowmeter carries out air test operation result curve map;
Principle of the present invention and main points are: a composite signal artificial body for generating is set in the conduit of flowmeter, it can produce a bigger pressure difference signal △ P, can produce again stable and strong whirlpool stream, pressure difference signal is spread out of by differential pressure pickup, and the whirlpool frequency f is received, spread out of by the frequency detector that is separated with artificial body for generating. Derivation is known according to bernoulli equation, has relation between pressure reduction (or the dynamic pressure that records) the △ P that this composite signal artificial body for generating produces and the volume flow Q:
In the formula: the K'-coefficient of flow
The volumetric flow rate that Q-records according to pressure reduction
The A-cross-section of pipeline is long-pending
Po-fluid general pressure
The Ps-hydrostatic pressure
Po-Ps-pressure differential (or dynamic pressure) △ P
ρ-fluid density
On the other hand, according to " Karman vortex street " principle, the whirlpool frequency f that this composite signal generation body produces is measured by frequency detecting element, and there are following relation in it and flow rate of fluid V,
f＝St (v)/(d) （2）
F-whirlpool frequency (HZ)
In the formula: the St-Strouhal number
The fluoran stream surface width of d-composite signal generation body
The V-rate of flow of fluid
After learning frequency f, have:
V＝ (d)/(St) f （3）
And then the relational expression between volume flow Q and frequency f:
Q＝ 1/(st) ·d·A·f （4）
The volumetric flow rate that Q-records according to the whirlpool frequency in the formula
The cross-sectional area of A-pipeline
Obviously, can draw ρ Q after recording pressure reduction △ P and frequency f
2And Q, as shown in the formula:
Get by (1) formula: ρ Q
2=(K'A)
2△ P (5)
Get by (4) formula: Q=1/ (st) dAf (6)
To represent ρ Q
2The signal that reaches Q is drawn out to specialized circuitry and handles, and is divided by promptly through divider:
(5) formula then gets the expression formula of mass rate N divided by (6) formula:
M= (ρQ
2)/(Q) =ρQ=K· (△P)/(f)
In the formula: the coefficient of flow (by measuring) of this composite signal of K-generation body
N=ρ Q-mass rate
The present invention is based on above-mentioned principle, can directly record mass rate accurately, parameters such as volumetric flow rate and fluid density.
The major technique measure is:
A, one composite signal generation body is installed in the meter run upstream, this generation body is a prism parts (triangular prism, rhombus column, rectangular column or six prisms etc.), body central axis both sides are taking place, two axial connecting pipes have paralleled to the axis, stagnation pressure connecting pipe and static pressure connecting pipe, body is met stream and the back of the body flows on the side face taking place, radially have stagnation pressure pressure guide hole and static pressure pressure guide hole along cylinder, communicate or signal communication with stagnation pressure connecting pipe and static pressure connecting pipe respectively, the pilot tubule is arranged in two connecting pipes or draw lead, be connected with a differential pressure pickup.By the pressure difference signal that connecting pipe or pressure guide hole place measure, after the differential pressure pickup processing, export square current output signal Ip that is directly proportional with instantaneous volume flow rate.It is that pressure guide hole (stagnation pressure pressure guide hole and static pressure pressure guide hole) with taking place on the body side face is split into through hole that above-mentioned pressure guide hole communicates with two connecting pipes, and fluid is directly communicated with two connecting pipes through each pressure guide hole.The signal communication of above-mentioned pressure guide hole and two connecting pipes is when detected fluid is dirty medium, utilizes piezoelectric ceramics to block each pressure guide hole, draws the electric signal of pressure reduction with lead.
Because this composite signal generation body has obtuse angle cross sectional shape (non-streamline), and definite burble point is arranged, when making fluid flow through this generation body, produce stable and uniform whirlpool.
B. on the meter run of composite signal generation body downstream certain distance, seal cover for seat fixed installation one and the frequency detector that body is separated takes place by one, this detecting device is made of detecting elements such as foil gauge or piezoelectric crystals, connect by prime amplifier and secondary epiphase, prime amplifier passes the pulse signal that amplifies exactly, is shown and instantaneous delivery current signal Iv by delivery rate numeral after the secondary list processing (LISP).
C. differential pressure pickup and frequency detector join with a circuit simultaneously, this circuit is provided with two electric currents earlier, electric pressure converter, convert pressure reduction instantaneous delivery current signal Ip and vortex instantaneous delivery electric current I v to voltage Vp and Vv, and with the output of converter input as a divider, voltage Vp and Vv are divided by obtain long-pending (being ρ Q) relevant voltage Vo with density p and flow Q, Vo is on the one hand through voltage-current converter, convert the electric current I o(4-20NA that is directly proportional with mass rate to) on the other hand, measure a frequency signal F(promptly becomes ratio with the fluid mass flow frequency signal) at Vo output termination voltage one frequency converter.
Below in conjunction with actual execute the example open in detail to the present invention:
Embodiment 1, and as shown in Figure 1 and Figure 2, in the conduit 1 of this flowmeter, by base 5 fixed installations one composite signal generation body 2, this generation body is rhombus columnar part (or being triangular prism, six prisms, rectangular column).Machined surface is fallen at rhombus column crest line place, in prism central axis both sides, parallel central axis has two connecting pipes, stagnation pressure connecting pipe 3 and static pressure connecting pipe 4, meet on the stream side face 11 at the generation body, radially have two or its number of several stagnation pressure pressure guide holes 10(and be 2 multiple) communicate with the stagnation pressure connecting pipe, radially opening two its numbers of static pressure pressure guide hole 10(on generation body back of the body stream side face 12 also can be one or more) communicate with generation body static pressure connecting pipe, fluid directly communicates with two connecting pipes through each pressure guide hole, pilot tubule 9 is housed with being connected in two connecting pipes with a differential pressure pickup 13, the pilot tubule is with △ P, reach differential pressure pickup, output after treatment and instantaneous volume flow rate square and the current output signal Ip that is directly proportional of fluid density, meanwhile, because this composite signal generation body has blunt cross sectional shape (non-streamline) and definite burble point is arranged, fluid is flowed through produce stable when body takes place and uniform eddy-currents.The meter run downstream of an appropriate location behind rhombus column composite signal generation body, by cover for seat 15 frequency detector is installed, after utilizing foil gauge (or piezoelectric crystal) 6 on this detecting device to detect the frequency f of whirlpool, through prime amplifier 7, the pulse duration frequency signal that records is sent to amplifier 8 exactly, receive to be handled by secondary table 14 then that back output integrated flow numeral shows and the instantaneous delivery electric current is exported Iv, detecting device be able to be experienced the whirlpool frequency signal that composite signal generation body produced apart from the distance of composite signal generation body with it and be advisable.Differential pressure pickup and frequency detector are with connecing a signal processing circuit, this circuit setting as shown in Figure 3, pressure reduction momentary current Ip, pass through current-voltage converter (I/v converter) output voltage V p and Vv respectively with whirlpool momentary current Iv, and a division circuit is set behind converter, with the output of front converter as the input of divider Vp and Vv are divided by obtain with density (ρ) and flow (Q) amass (ρ Q) relevant voltage Vo, Vo converts the electric current I o that is directly proportional with mass rate to through voltage one current converter (V/I), can measure the whirlpool frequency f at Vo output termination one voltage-frequency converter (V/f) simultaneously, promptly represent the frequency signal of fluid mass flow.
The pressure difference signal △ P that above-described composite signal generation body produces can be detected by piezoelectric sensor and spread out of.Specific implementation method is:
Embodiment 2:
As shown in Figure 4: when measured medium is dirty fluid, for preventing the obstruction of pod apertures, in each pressure guide hole 10 with the composite signal generation body described in the embodiment 1, fill piezoelectric sensor 18, fluid is not entered in stagnation pressure conduit and the static pressure conduit, pressure guide hole and two connecting pipes are become signal communication.On piezoelectric sensor, draw lead 19, make the pressure difference signal of sensing on the piezoelectric sensor directly send into converter.Thereby obtain representing the marking current Ip of pressure reduction.
Effect of the present invention: this quality flowmeter adopts the combination mode of separating of composite signal artificial body for generating and frequency detector, is equipped with specialized circuitry and processes, thereby directly obtain quality flow, the parameters such as volume flow or density. It is not subjected to the impact of the factors such as fluid components, density, temperature, pressure, has effectively solved the measurement difficult problem of the quality flow of liquid, gas (comprise and become the component gas-liquid), obtains the linear output of desirable quality flow, crushing is little, less energy consumption is measured accurately good stability.
Experimental result 1: this flowmeter the discharge calibration equipment of Φ 50 calibers obtained as shown in Figure 6A ρ Q and electric current I o relation curve (Io withBe directly proportional), and the volume flow Q shown in Fig. 6 B and the relation curve of frequency Iv, from the preferably linear output of survey data tool people of scheming visible this flowmeter.
Experimental result 2, this flowmeter is done measured medium with air, utilizes bell-jar gas flow calibration equipment to do test at the pipeline of Φ 50, obtains the ρ Q of the gas shown in Fig. 7 B2And the relation curve between the pressure reduction, and the volume flow shown in Fig. 7 A and the relation curve between the frequency have also obtained satisfied effect.
Claims (6)
1, a kind of driect type mass flowmeter comprises signal generator, frequency detector, and differential pressure pickup and corresponding specialized circuitry is characterized in that:
A, a composite signal generation body is installed in the meter run upstream, this generation body is prism parts, in prism central axis both sides, two the axial connecting pipes that paralleled to the axis are stagnation pressure connecting pipe and static pressure connecting pipe, meet on stream and the back of the body stream side face and radially have stagnation pressure guide hole and static pressure pressure guide hole in that body takes place, communicate with stagnation pressure connecting pipe and static pressure connecting pipe, the pilot tubule is all arranged in connecting pipe or draw lead, be connected with the differential pressure pickup that is contained in generation body upper end.
B, behind composite signal generation body a distance, be equipped with one with the frequency detector that body is separated takes place, and be fixed on the meter run by a sealing cover for seat, detecting device connects by prime amplifier and secondary epiphase.
C, differential pressure pickup are connected with a signal processing circuit with the frequency detector output terminal, pressure reduction electric current and frequency current are at first respectively by two current-voltage converters, two above-mentioned converters are output as the input of a fly-ash separator, signal output part at divider connects simultaneously-voltage-current converter and-voltage-frequency converter, convert voltage signal to current signal and frequency signal.
2, mass flowmeter according to claim 1 is characterized in that: described composite signal generation body prism is triangular column or six prisms or rhombus column or rectangular column outward.
3, mass flowmeter according to claim 1 is characterized in that, described stagnation pressure pressure guide hole number is 2 multiple, and static pressure guide hole number is one or more.
4, mass flowmeter according to claim 1, it is characterized in that, described stagnation pressure pressure guide hole and static pressure pressure guide hole communicate with two connecting pipes, be that pressure guide hole is split into through hole, fluid directly communicates with connecting pipe, the pilot tubule of in stagnation pressure connecting pipe and static pressure connecting pipe, packing into, and join with differential pressure pickup.
5, mass flowmeter according to claim 1, it is characterized in that signal communication between described stagnation pressure pressure guide hole and static pressure pressure guide hole and two connecting pipes is to fill piezoelectric sensor in the pressure guide hole, on this element, be connected to lead, join with signal processing circuit.The electric signal that output is directly proportional with pressure reduction.
6, mass flowmeter according to claim 1 is characterized in that, described detecting device is made of foil gauge or piezoelectric crystal or other detecting element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 91100796 CN1018764B (en) | 1991-02-11 | 1991-02-11 | Mass flowmeter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 91100796 CN1018764B (en) | 1991-02-11 | 1991-02-11 | Mass flowmeter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1053493A true CN1053493A (en) | 1991-07-31 |
| CN1018764B CN1018764B (en) | 1992-10-21 |
Family
ID=4904822
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 91100796 Expired CN1018764B (en) | 1991-02-11 | 1991-02-11 | Mass flowmeter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1018764B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100424475C (en) * | 2005-12-12 | 2008-10-08 | 杭州术通高端仪器有限公司 | External multi-point inductive flow sensor |
| CN100424474C (en) * | 2005-12-12 | 2008-10-08 | 杭州术通高端仪器有限公司 | Externally-connected inductive flow sensor |
| CN102445243A (en) * | 2011-11-08 | 2012-05-09 | 云南大学 | Flow-measuring device with flow stabilizing function |
| CN102645248A (en) * | 2012-05-18 | 2012-08-22 | 中国计量学院 | Self-correction heat type-precession vortex combined type gas flow measurement method |
| CN104913824A (en) * | 2015-06-24 | 2015-09-16 | 济南康能电力技术有限公司 | Powder mass flowmeter |
| CN109255305A (en) * | 2018-08-18 | 2019-01-22 | 深圳长元知识产权服务有限公司 | A kind of biometric devices and the shared device using the device |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6564824B2 (en) * | 2001-04-13 | 2003-05-20 | Flowmatrix, Inc. | Mass flow meter systems and methods |
-
1991
- 1991-02-11 CN CN 91100796 patent/CN1018764B/en not_active Expired
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100424475C (en) * | 2005-12-12 | 2008-10-08 | 杭州术通高端仪器有限公司 | External multi-point inductive flow sensor |
| CN100424474C (en) * | 2005-12-12 | 2008-10-08 | 杭州术通高端仪器有限公司 | Externally-connected inductive flow sensor |
| CN102445243A (en) * | 2011-11-08 | 2012-05-09 | 云南大学 | Flow-measuring device with flow stabilizing function |
| CN102445243B (en) * | 2011-11-08 | 2012-11-21 | 云南大学 | Flow-measuring device with flow stabilizing function |
| CN102645248A (en) * | 2012-05-18 | 2012-08-22 | 中国计量学院 | Self-correction heat type-precession vortex combined type gas flow measurement method |
| CN102645248B (en) * | 2012-05-18 | 2013-10-02 | 中国计量学院 | Self-correction heat type-precession vortex combined type gas flow measurement method |
| CN104913824A (en) * | 2015-06-24 | 2015-09-16 | 济南康能电力技术有限公司 | Powder mass flowmeter |
| CN104913824B (en) * | 2015-06-24 | 2018-07-06 | 济南康能电力技术有限公司 | A kind of powder quality flowmeter |
| CN109255305A (en) * | 2018-08-18 | 2019-01-22 | 深圳长元知识产权服务有限公司 | A kind of biometric devices and the shared device using the device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1018764B (en) | 1992-10-21 |
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