CN1016275B

CN1016275B - Vortex flowmeter

Info

Publication number: CN1016275B
Application number: CN 86104243
Authority: CN
Inventors: 岩本哲夫; 雨森宏之; 西山繁
Original assignee: Tokico Ltd
Current assignee: Hitachi Ltd
Priority date: 1985-06-20
Filing date: 1986-06-20
Publication date: 1992-04-15
Also published as: CN86104243A

Abstract

The vortex flowmeter consists of a vortex generating body and at least one pair of sensitive parts. The vortex generating body is installed in the pipeline of the measured fluid flow path, so that the measured fluid flowing through the pipeline will generate a Kalman vortex, and the two sides of the vortex generating body are opened, and one end is connected through the installation, and a pair of differential pressure introduction holes are installed. , used to introduce the pressure change brought by the generation of the Kalman vortex of the measured fluid; the at least one pair of sensitive parts are separated along the axial direction of the pipeline from the detection part installed outside the vortex generator The main body outputs a flow measurement signal corresponding to the differential pressure from the differential pressure inlet hole.

Description

Swirl flowmeter

The present invention relates to swirl flowmeter, particularly, the structure of the vortex generator of detected fluid generation vortex simplified in the stream that is arranged on fluid, even and pipeline vibration is arranged but vortex flowmeter that measuring accuracy does not also reduce.

Past, vortex generation body is installed in stream, because this vortex generation body, detected fluid produces Karman vortex at downstream side, and detects the pressure variation corresponding with vortex.Thereby make the swirl flowmeter practicability of the flow rate that detects detected fluid.Past, having the formation that electrostatic capacitive detects swirl flowmeter partly is, be provided with recessed part in vortex generation body two sides, and on this part, install and fix battery lead plate, simultaneously, with the slight gap place of this electrode install one can bear detected fluid pressure change, as the diaphragm of movable electrode, and the space enclosing liquid between battery lead plate and diaphragm, simultaneously, a pair of space is communicated with and enclosing liquid is encapsulated in the inside.In this swirl flowmeter, be accompanied by flowing of detected fluid, the detected fluid that flows through in the both sides of vortex generation body has alternately produced Karman vortex, the variation of corresponding its pressure, a pair of diaphragm produces displacement.Carry out the electrostatic capacitance change between diaphragm and fixed electorde of detecting of electricity then, thereby measured flow.

Yet along with flowing of pipeline inner fluid, pipeline produces vibration, the result, and vibration is just passed to the flow detection part that directly is fixed on the pipeline by pipeline.Flow detection is partly carried out flow measurement when being subjected to the vibration of being transmitted by pipeline.

Generally, detect a pair of responsive part, be installed on the horizontal direction that is orthogonal with pipeline axial by the pressure reduction that vortex generator produced.But, as the vibration that pipeline passed, pipeline axially on be difficult for starting of oscillation, even starting of oscillation is also smaller.But it is then bigger at the horizontal direction and the vibration composition on the vertical direction that are orthogonal with pipeline axial.Therefore, the flowmeter in past is owing to a pair of responsive part is installed on the horizontal direction that is orthogonal with pipeline axial, one has the vibration generation on the horizontal direction of pipeline, then shakes in the horizontal direction with the enclosing liquid that is communicated with filling in the part at a pair of responsive diaphragm cavity partly.Therefore, the swirl flowmeter in past, owing to produce vibration in the pipe level direction, the liquid of encapsulation is subjected to acceleration between a pair of responsive part, because the inertia of enclosing liquid, metallic membrane has produced displacement as a result.Then have such shortcoming in this case, promptly form the variation of electrostatic capacitance amount, promptly export as signal when this variation is detected at last owing to such pipe vibration makes the displacement of metallic membrane.In addition, when carrying out the little small amount of flow measuring of metallic membrane displacement, very difficult differentiation is because the pressure reduction that Karman vortex forms makes the metallic membrane displacement or because pipe vibration makes the metallic membrane displacement.Therefore when low discharge is measured, must reduce the sensitivity of circuit so that because unlikely being detected of variation of the electrostatic capacitance amount that the metallic membrane that pipe vibration brings skew is produced.Therefore, such shortcoming is just arranged, promptly can not carry out forming along with Karman vortex the small amount of flow measuring of the little displacement of metallic membrane, the result narrows down the measurement range of flow.

Therefore, the present invention provides new, useful swirl flowmeter for the shortcoming of removing the above-mentioned past.Below, with accompanying drawing each is implemented example and be illustrated.

The 1st figure is the back view that the 1st of swirl flowmeter of the present invention is implemented example,

The 2nd figure is the vertical profile outboard profile of swirl flowmeter among the 1st figure,

The 3rd figure be among the 1st figure swirl flowmeter along the cross-sectional view of III-III line,

The 4th figure is the circuit diagram of the used testing circuit of the swirl flowmeter among the 1st figure,

The 5th figure is other cross-sectional view of implementing the vortex generation post of example,

The 6th figure is the vertical profile back view that the 2nd of swirl flowmeter of the present invention is implemented example,

The 7th figure is the detection general view partly of the swirl flowmeter among the 6th figure,

The 8th figure is the vertical profile outboard profile of the swirl flowmeter among the 6th figure,

The 9th figure is the circuit diagram of the used testing circuit of the swirl flowmeter among the 6th figure,

The 10th figure is that other implements the general view that example detects part.

The swirl flowmeter 10 of example is implemented in conduct shown in the 1st figure to the 3 figure the of the present invention the 1st, roughly formed: pipeline 11 Hes that have ring flange by following each part, be vertically mounted on vortex generation post 12 Hes of the middle part of pipeline 11, with the connected detection that is installed in top, pipeline 11 outside of vortex generation post 12 partly 13 and with detect the partly 13 following testing circuits that are electrically connected.Have differential pressure at the middle and upper part branch of two sides 12a, the 12b of vortex generation post 12 and import opening 14a, 14b.Above differential pressure entrance hole 15a, the 15b that is communicated with by these two opening 14a, 14b extends in vortex generation post 12.In addition, opening 14a, 14b are as long as left and right symmetrically is arranged on the vortex generation post, and be not strict for the requirement of the installation accuracy of opening 14a, 14b and differential pressure entrance hole 15a, 15b etc., thereby the low cost of vortex generation post 12.The top of vortex generation body 12 penetrates the tube wall of pipeline 11.

The member that forms entrance hole 16 partly is equipped with in the tube wall periphery of pipeline 11 and detection between 13, on parts 16, form oblique differential pressure entrance hole 17a, the 17b that is connected with differential pressure entrance hole 15a, 15b, in addition, be provided with garden shape recessed partly 18a, the 18b of differential pressure entrance hole 17a, 17b opening in the above.

On member 16, be equipped with and detect part 13.Be equipped with in 13 towards recessed part 18a, 18b, the diaphragm 19a, the 19b that make as garden shape movable electrode, by stainless steel detecting partly, in addition, and the space 20a between diaphragm 19a, the 19b, 20b top electrode 21a, the 21b that is done by conductive foil as garden shape fixed electorde is installed.Above-mentioned space 20a, 20c is connected by electrode 21a, 21b and access 22, and the incompressible fluid of encapsulation in this 20a, 20b and intercommunicating pore 22 is as liquid such as silicone oil 23.

Diaphragm 19a and electrode 21a form one as responsive variable capacity device 24a partly; Diaphragm 19b and electrode 21b form another one as sensitivity variable capacity device 24b partly.The lead (not shown) that connects these variable capacity devices is introduced respectively in 25 in the circuit casing (not shown) by managing, and receives testing circuit.

Here, a pair of variable capacity device 24a, 24b are installed in along pipeline 11 axial, leave on the position of certain intervals, for handle and pipeline 11 axially be orthogonal leave on the direction at interval and the differential pressure of the opening 14a, the 14b that install guide to be installed at interval pipeline 11 on axially recessed part 18a, 18b and differential pressure entrance hole 17a, the 17b of inclination are installed.

Also be provided with in addition: form the

coil

31,32 of bridge diagram 30 with capacitor 24a and 24b, give the alternating current 33 of this bridge diagram 30 for alternating current, 30 outputs are amplified to bridge diagram amplifying circuit 34, demodulator circuit 35 and Schmidt circuit 36.From the proportional pulse signal of flow velocity of Schmidt circuit 36 output repetition frequencys and detected fluid, supply with the circuit of back again by exit point 37.

In the swirl flowmeter 10 of above-mentioned formation, in pipeline 11 when detected fluid when the F direction flows, alternately produce Karman vortex 26 in the both sides of vortex generation post 12.Thus, the pressure of the antiphase of the detected fluid that is produced at two sides 12a and 12b changes, by opening 14a, 14b, and differential pressure entrance hole 15a, 15b, 17a, 17b, recessed partly 18a, 18b and be conducted to the one side of diaphragm 19a and 19b.Diaphragm 19a and 19b be subjected to this variation pressure and alternately upper and lower displacement of antiphase, the capacity of capacitor 24a increases and decreases thereupon, the capacity of capacitor 24b subtracts thereupon, increases.The volume change cycle of capacitor 24a and 24b is corresponding and inversely proportional with flow velocity with the generating period of vortex 26.Thereby bridge diagram 30 produces to use with the proportional frequency of flow velocity the signal that exchanges stream source 33 is carried out the output of amplitude modulation, and exports repetition frequency and the proportional pulse signals of flow velocity from Schmidt circuit 36.The cycle by measuring this output signal and the number of output signal can be obtained flow velocity and flow.

Here, when adding external vibration for pipeline 11, detect partly 13 also vibrations together.Yet, as previously mentioned, give pipeline 11 added vibrations, more in the vibration of widthwise than axial vibration.

But, as mentioned above, detect partly 13 variable capacity device 24a, 24b be installed in side by side pipeline 11 axially on, the intercommunicating pore 22 that connects space 20a, the 20b of two variable capacity device 24a, 24b and encapsulated liquid 23 is to be positioned on pipeline 11 axial.Therefore, even pipeline 11 is done the vibration of transverse direction, encapsulation liquid 23 vibrates too, but the variation of the pressure that vibration produced of enclosing liquid 23 also adds less than on diaphragm 19a, the 19b.In addition, even be added on diaphragm 19a, the 19b, but, can not produce the output that mistake is surveyed owing to homophase is cancelled each other by the pressure that vibration the produced variation of enclosing liquid 23.

In addition, in above-mentioned enforcement example, though be with having the differential pressure entrance hole 17a of inclination, the parts 16 of 17b, be communicated with opening 14a, 14b that pipeline 11 transversely is provided with at interval and pipeline 11 axially on the recessed part 18a, the 18b that are provided with at interval, but also can be used on the vortex generation post 40 that the transversal section is represented among the 5th figure and omit member 16.In this case, on vortex generation post 40, be provided with by opening 14a, the 14b of both sides mutually to the hole 41a, the 41b that extend in the other direction and the hole 42a, the 42b that just extend vertically upward by that ditch portion.Hole 42a, 42b transversely separate pipeline 11, shown in the 2nd figure, at that with pipeline 11 axially on the recessed part 18a, the 18b that separate be connected.

Below, implement example with regard to the 6th figure to the 8 figure as the 2nd of swirl flowmeter of the present invention and describe.

As mentioned above, when pipe vibration, although the axial vibration of pipeline is difficult for starting of oscillation with the meet at right angles easy starting of oscillation of vibration of direction of pipeline axial, but pipeline axially on also more or less vibration.Implement in the example the above-mentioned the 1st because a pair of variable condenser installs along pipeline axial, thereby pipeline axially on one vibration is arranged, the problem that measuring accuracy descends then appears.This 2nd implements example, not only with the rectangular direction of pipe axis on vibration is arranged, even on pipeline axial, there is vibration also can make the unlikely decline of measuring accuracy.

By as the metallic membrane of movable electrode with the constituting of the responsive variable condenser partly of the conduct that makes of the electrode that is relatively fixed in the space with it, with a pair of variable condenser space separately by access to connection, and be full of formation of enclosing liquid etc. therein, identical with above-mentioned enforcement example, therefore, its detailed description is omitted.

The formation of the detection part 51 of this enforcement example swirl flowmeter 50 and above-mentioned enforcement example are different.

On the member 52 of the formation entrance hole of installing on the outer wall of pipeline 11, be respectively arranged with: be connected with differential pressure entrance hole 15a and rough mutually differential pressure entrance hole 53a, the 53d that tilts to extend to opposite direction, be connected with differential pressure entrance hole 15b and rough mutually differential pressure entrance hole 53b, the 53c that extends to inclination in the other direction.Differential

pressure entrance hole

53a and 53b do three-dimensional intersecting.

Recessed part 54a～54d that the opening of differential pressure entrance hole 53a～53d is used is set on member 52.Here, as the clear expression of the 7th figure, by differential pressure entrance hole 15a, import recessed part 54a, the 54d of mutual identical differential pressure by differential

pressure entrance hole

53a, 53d, be set at facing on left front, the right back position on the liquid flow direction,, be set on right front, the left back position by

recessed part

54b, 54c that differential

pressure entrance hole

53b, 53c import mutual identical differential pressure by differential pressure entrance hole 15b.

An installation component 56 is installed on member 52, and face below installation component 56 facing to recessed partly 54a～54d, is installed with variable condenser 55a～55d respectively.Here, with the pipeline direction that axially (identical with the flow direction F of fluid) is orthogonal on the movable electrode of laterally arranged side by side a pair of

variable capacitance

55c, 55d and the space between the fixed electorde, be connected by access 58, and full of liquid therein.Similarly horizontal another space to variable condenser 55a, 55b arranged side by side, also the access 57 by full of liquid is interconnected.

These capacitors 55a～55d, shown in the 9th figure, connecting, as compare from the 4th figure and the 9th figure find out,

coil

31,32, with with the bridge diagram of the 4th figure in the suitable on one side capacitor 55a of capacitor 24a and the parallel circuit of 55d be connected, and be connected with the 55c parallel circuit with the capacitor 55b suitable on one side with capacitor 24b.

When measuring flow, and differential pressure that Karman vortex caused that at vortex generation post 12 downstream sides take place corresponding with the flow of the detected fluid that in pipeline 11, flows, opening 14a, 14b by vortex generation post 12, differential pressure

pressure guide hole

15a, 15b, 53a～53d is imported recessed partly 54a～54d respectively.Here, recessed partly 54a is imported identical differential pressure with 54d, recessed partly 54b is imported identical differential pressure with 54c.Therefore, because the variation of differential pressure, the static capacity of capacitor 55a, 55d increases simultaneously, subtracts, and phase place is opposite therewith, and the static capacity of

capacitor

55b, 55c subtracts simultaneously, increases.

Now the pipeline with regard to the swirl flowmeter 50 of above-mentioned formation produces vibration, detects partly that 51 situation is illustrated and pass to.

At first, look to detect partly 51 be subjected to along pipeline 11 axially, indicate the situation of vibrating on the direction of symbols Z, because

access

57,58 is on the direction that is orthogonal with the Z direction, the enclosing liquid that therefore is filled in the space of

access

57,58 and each capacitor 55～58 is subjected to less than the acceleration that makes each diaphragm displacement.Therefore, even on the Z direction, there is vibration that measuring accuracy is descended.

Secondly, flow detection part 51 is when vibrating with the vertical direction up and down that axially is orthogonal (arrow Y direction among the 6th figure) of pipeline 11, the diaphragm as movable electrode of each capacitor 55a～55d vibrates on same Y direction respectively, with the displacement homophase that is caused by diaphragm inertial force.The static capacity of the homophase of these capacitors 55a～55d changes, and offsets in bridge diagram 60.Therefore, even produce vibration on this arrow Y direction, measuring accuracy can not descend yet.

Below, just stream detects partly 51 at horizontal direction (the arrow X among the 6th figure that axially is orthogonal with pipeline 11 ₁, X ₂Direction) going up the situation of vibrating is illustrated.

At arrow X ₁When the oscillating component on the direction affacted on the flow detection part 51, the enclosing liquid in the

access

57,58 relatively was subjected to arrow X ₂The acceleration of direction.For this reason, the inertial force of enclosing liquid just acts on each space of capacitor 55a, the 55c in left side, and diaphragm is to the direction displacement of leaving fixed electorde.And the diaphragm of capacitor 55b, the 55d on right side is to the direction displacement near fixed electorde.Therefore, the static capacity of capacitor 55a, 55c reduces, and simultaneously, the static capacity of

capacitor

55b, 55d increases.

So the static capacity of the capacitor 55a on one side of parallel circuit reduces in the bridge diagram 60 of the 9th figure, meanwhile, the static capacity of the capacitor 55d of another side increases.Equally, the static capacity of the capacitor 55b on one side of other parallel circuit increases, and simultaneously, the static capacity of the capacitor 55c of another side reduces.Thereby the static capacity variation of

capacitor

55a, 55d, 55b, 55c is cancelled.Like this, even because pipe vibration, at arrow X ₁Flow testing division part 51 displacements on the direction, the also unlikely balance that loses of bridge diagram 60, also no signal output of bridge diagram 60.

In addition, at the arrow X of pipe vibration ₂The oscillating component of direction acts on flow detection partly on 51 the time, can keep the balance of bridge diagram 60 similarly and signal that unlikely output error detects.

So, no matter in any direction produce vibration, the influence that the swirl flowmeter 50 of this enforcements example can not be vibrated and export to miss and survey signal, and can correctly carry out flow measurement.

In addition, owing to the electric bridge electricity is stepped on 60 and can not exported mistake by pipe vibration and survey signal, thereby the gain that can improve amplifying circuit 34, and can be cross over the wide-range of low discharge scope, correctly carry out flow measurement.

Also have, because two couples of responsive partly 55a and 55b, 55c and 55d have been installed, even for example on one side responsive partly 55a, 55b are out of order, the also flow measurement that can meet an urgent need by responsive partly 55c, the 55d of another side.Therefore, before repairing, do not cause flow measurement to be interrupted, protect and help maintenance.

In addition, though the structure in above-mentioned enforcement example is differential pressure entrance hole 15a, 15b to diverge respectively and is connected to differential pressure entrance hole 53a～53d,, be not limited thereto, for example, differential pressure entrance hole 53a～53d also can be communicated to 4 differential pressure entrance holes that are provided with respectively on vortex generation post.

The 10th figure has showed the detection part 51A as another enforcement example that detects part 51.Implement to use in the example vortex generation post 40 shown in the 5th figure to come alternative vortex generation post 12 at this.A pair of recessed part 54a, 54b, capacitor 55a, 55b are installed with facing to the flow direction F of fluid left front, right backly, and another is to recessed partly 54c, 54d, and

capacitor

55c, 55d are installed with left back, right frontly.The space of capacitor 55a, 55b is communicated with by the access 57 of enclosing liquid; The space of

capacitor

55c, 55d is communicated with by the access 58 of enclosing liquid.Here, be communicated with 57 and 58 and make three-dimensional intersection.Be orthogonal on the direction with pipeline, laterally recessed part 54a, 54d arranged side by side is connected with 70a, the 70d of connection differential pressure entrance hole 41b, 42b.It is in addition, recessed that partly 54b, 54c are connected with 70b, the 70c of connection differential

pressure entrance hole

41a, 42b.

This structure also can obtain and detects partly 51 identical effects.

Claims

1. A vortex flowmeter has:

The pipeline through which the measured fluid flows;

A vortex generating body is provided in the pipeline;

A first differential pressure introduction hole for introducing the pressure generated by the vortex is provided on one side of the vortex generating body;

On the other side of the vortex generating body, a second differential pressure introduction hole for introducing the pressure generated by the vortex is provided;

The flow detection part, which is arranged outside the aforementioned pipeline, corresponds to the pressure measurement flow introduced by the first and second differential pressure inlet holes;

The flow detection part consists of the following parts:

Two sets of sensors, which are respectively arranged upstream on one side of the introduction hole and downstream on the other side, are composed of two electrodes, a diaphragm whose position is changed corresponding to the pressure introduced by the first and second differential pressure introduction holes As a movable electrode, the fixed electrode detects the position change of the diaphragm;

The diaphragm chamber is formed by the fixed electrode part and the diaphragm part of the two groups of sensors, and the first and second communication paths filled with the filling liquid are set to communicate with the diaphragm chambers on two different sides;

The pressure introduced by the first and second differential pressure introduction holes is supplied to the passages of the aforementioned two sets of sensor diaphragms;

The path is composed of a first communication path and a second communication path;

The first communication path is a passage connecting the first differential pressure introduction hole with the sensor on the upstream side and the sensor on the other downstream side;

The second communication path is a passage connecting the second differential pressure introduction hole with the sensor on the other upstream side and the sensor on the downstream side;

This vortex flowmeter has the following features: the aforementioned first communication path communicates with the upstream diaphragm chamber; the aforementioned second communication path communicates with the downstream diaphragm chamber.

2. A vortex flowmeter has:

The pipeline through which the measured liquid flows;

A vortex generating body is arranged in the pipeline;

A second differential pressure introduction hole for introducing the pressure generated by the vortex is provided on the other side of the vortex generating body;

The flow detection part, which is arranged on the outside of the aforementioned pipeline, corresponds to the pressure measurement flow introduced by the first and second differential pressure inlet holes;

The traffic detection part is composed of several above parts:

Two sets of sensors, which are respectively arranged on the upstream part of the aforementioned one side and the downstream part of the other side, are composed of two electrodes, and the diaphragms whose positions are changed corresponding to the pressure introduced by the aforementioned first and second differential pressure introduction holes As a movable electrode, the fixed electrode detects the position change of the diaphragm;

The diaphragm chamber is composed of the fixed electrode part and the diaphragm part of the two groups of sensors. In order to communicate with the two diaphragm chambers located on different sides, the first and second communication paths filled with the filling liquid are set;

The passage for supplying the pressure of the aforementioned first and second differential pressures into the hole guides for each diaphragm part of the aforementioned two groups of sensors;

The path is composed of a first connecting path and a second connecting path;

The first communication path is a passage connecting the aforementioned first differential pressure introduction hole and the sensor portion located on the aforementioned upstream or downstream side and their other side;

The second communication path is a passage that communicates with the aforementioned second differential pressure introduction hole and the aforementioned sensor portion located downstream or upstream and on the other side thereof;

This vortex flowmeter has the following characteristics:

The aforementioned first communication path communicates with the diaphragm chamber located on the upstream side and the diaphragm chamber located on the other downstream side;

The second communication path communicates with the diaphragm chamber on the other upstream side and the diaphragm chamber on the downstream side.

3. The vortex flowmeter described in claim 1 or 2 has: each fixed electrode part and each diaphragm part of the aforementioned 2 groups of sensors form a pair of variable capacity capacitors, corresponding to the change of the capacity of a pair of variable capacity capacitors , the measurement signal is output by the detection circuit.

4. The vortex flowmeter as claimed in claim 1 or 2 has: the variable capacitors as the sensing part of the same differential pressure introduced through the first and second differential pressure introduction holes are connected in parallel, as the first parallel connection, the As the variable capacitor of the sensor part of the same differential pressure introduced through the other side of the first and second differential pressure introduction holes, it is connected in parallel as the second parallel connection, and the first and second parallel connections are respectively connected to the coil and the bridge to constitute detection circuit.