CN201787975U - Dual-bluff-body vortex flowmeter with built-in Venturi tube - Google Patents

Dual-bluff-body vortex flowmeter with built-in Venturi tube Download PDF

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Publication number
CN201787975U
CN201787975U CN2010201058952U CN201020105895U CN201787975U CN 201787975 U CN201787975 U CN 201787975U CN 2010201058952 U CN2010201058952 U CN 2010201058952U CN 201020105895 U CN201020105895 U CN 201020105895U CN 201787975 U CN201787975 U CN 201787975U
Authority
CN
China
Prior art keywords
bluff body
venturi tube
built
bluff
flowmeter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CN2010201058952U
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Chinese (zh)
Inventor
傅新
申慧敏
叶朋
赵培华
邹宇清
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tancy Instrument Group Co Ltd
Zhejiang University ZJU
China United Coalbed Methane Co Ltd
Petrochina Coalbed Methane Co Ltd
Original Assignee
Tancy Instrument Group Co Ltd
Zhejiang University ZJU
China United Coalbed Methane Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tancy Instrument Group Co Ltd, Zhejiang University ZJU, China United Coalbed Methane Co Ltd filed Critical Tancy Instrument Group Co Ltd
Priority to CN2010201058952U priority Critical patent/CN201787975U/en
Application granted granted Critical
Publication of CN201787975U publication Critical patent/CN201787975U/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Abstract

The utility model discloses a dual-bluff-body vortex flowmeter with a built-in Venturi tube. The dual-bluff-body vortex flowmeter comprises a pipe, a front bluff body, a rear bluff body, two sensors and a flowmeter secondary instrument, the Venturi tube is embedded in the outer round pipe, the front bluff body and the rear bluff body which are perpendicular to the axis of the pipe and have non-streamlined cross sections are mounted in the Venturi tube, the sensors are respectively mounted at symmetrical positions on two sides of the rear bluff body, and the two sensors are connected with the secondary instrument outside the pipe via circuits. Change law of flow rate of fluid is determined according to change of area of the caliber, the flow rate of fluid is increased gradually along with a conical reducing section of the built-in Venturi tube and is the maximum at the throat of the Venturi tube, periodically alternative shedding Karman vortex street generated by the accelerated fluid at the downstream of the front bluff body is excited secondarily by action of the rear bluff body so as to obtain secondary Karman vortex street which is more stable and higher in vibration, thereby increasing low-rate measurement precision and flow of starting of oscillation of the flowmeter and reducing the lower limit of measurement of the flowmeter.

Description

The two bluff body vortex shedding flow meters of built-in venturi-type
Technical field
The utility model relates to a kind of device of measuring fluid flow, especially relates to the two bluff body vortex shedding flow meters of a kind of built-in venturi-type.
Background technology
When fluid is flowed through the blunt form bluff body, can form Karman vortex street in the downstream of bluff body, follow alternately coming off of vortex, can cause the vibration of fluid in the downstream of bluff body, within the specific limits, the frequency of fluid oscillation is directly proportional with flow rate of fluid.Utilize the vortex shedding flow meter of this principle development to obtain using more widely at home and abroad.
The principal character of existing vortex shedding flow meter is that the bluff body that the cross section is a blunt form is installed in runner, in bluff body or its downstream installation and measuring element, utilize secondary instrument that sensor is come off or the vibration signal of fluid is handled to vortex, and be converted to the flow of fluid by instrument coefficient.There is measurable flux lower limit problem of higher in existing vortex shedding flow meter.Vortex shedding flow meter requires to measure in certain flow rates, the frequency that vortex comes off is relevant with Strouhal number (Strouhal Number), concern as follows: (f is the frequency that stable vortex comes off to f=(v/d) St, St is a Strouhal number, v is the flow velocity of detected fluid, d is that the post of bluff body is wide), studies show that Strouhal number is the function of Reynolds number in the certain flow scope, the flow velocity of detected fluid and the frequency that vortex comes off satisfy proportional relation at this moment, but Reynolds number hour, fluid oscillation is very faint, signal to noise ratio (S/N ratio) can not satisfy the detection requirement, the metering lower limit of therefore existing vortex shedding flow meter generally is taken at about reynolds number Re=2000, has greatly limited the measures range of flowmeter.
Summary of the invention
The purpose of this utility model is to provide a kind of built-in venturi-type two bluff body vortex shedding flow meters.
The technical scheme that its technical matters that solves the utility model adopts is:
It comprises pipeline, preceding bluff body, back bluff body, two sensors and flowmeter secondary instrument the utility model, externally circular pipe is built-in with Venturi tube, be equipped with in the Venturi tube perpendicular to conduit axis, its xsect is the preceding bluff body and the back bluff body of blunt form, in bluff body symmetria bilateralis position, back the first sensor and second sensor are housed respectively, first sensor is connected by the outer secondary instrument of circuit and pipeline respectively with second sensor.
Be 0.6DN~1.5DN apart between bluff body and the back bluff body end face before described, wherein DN is the diameter of pipeline, and the shape of cross section of two blunt form bluff bodies is Shape, Shape, Shape or Shape.
Described xsect is the preceding bluff body of blunt form and throat place or the flow speed stability position, throat front and back that the back bluff body is installed in Venturi tube.
Described two sensors are piezoelectric transducer or capacitance type sensor.
The beneficial effects of the utility model are:
1, utilize two bluff body unitized constructions of optimizing to cause the overlapping phenomenon of vortex, can obtain stable more, the stronger fluid oscillation signal of vibration, under the identical situation of Reynolds number, descended 2~4 times with the fluid-velocity survey lower limit of the linear corresponding relation of vibration frequency, significantly enlarged by the comparable existing vortex shedding flow meter of measurement range of the two bluff body vortex shedding flow meters of the built-in venturi-type of this principle design.
2, the Changing Pattern of built-in Venturi tube inner fluid speed is by the variation decision of caliber area, make rate of flow of fluid increase gradually with the circular cone contraction section, and reach maximum at its throat place, entering circular cone diffuser flow velocity subsequently reduces, bluff body is placed in throat place or flow speed stability position, throat front and back, reaches starting of oscillation flow that reduces flowmeter and the purpose that improves low fluid-velocity survey precision.
Description of drawings
Fig. 1 is a structured flowchart of the present utility model.
Fig. 2 is a various bluff body cross-sectional view of the present utility model.
Among the figure: 1. pipeline, 2. Venturi tube, 3. before bluff body, 4. back bluff body, 5. sensor, 6. sensor, 7. outlet line, 8. flowmeter secondary instrument.
Embodiment
Below in conjunction with drawings and Examples the utility model is further specified.
As shown in Figure 1, it comprises pipeline 1, preceding bluff body 3, back bluff body 4, two sensors 5,6 and flowmeter secondary instruments 7.Externally Yuan Xing pipeline 1 is built-in with Venturi tube 2, be equipped with perpendicular to conduit axis in the Venturi tube 2, its xsect is the preceding bluff body 3 and the back bluff body 4 of blunt form, in bluff body 4 symmetria bilateralis positions, back the first sensor 5 and second sensor 6 are housed respectively, first sensor 5 is connected by the outer secondary instrument 7 of circuit 8 and pipeline respectively with second sensor 6.
As shown in Figure 2, preceding bluff body 3 of the present utility model and back bluff body 4 are blunt form cylinder metal bluff body, and at a distance of being 0.6DN~1.5DN, wherein DN is the diameter of pipeline 1, its xsect between preceding bluff body 3 and back bluff body 4 end faces Shape shown in Fig. 2 (a), or Shape shown in Fig. 2 (b), or Shape shown in Fig. 2 (c), or Shape is shown in Fig. 2 (d).Optimum distance between preceding bluff body 2 and back bluff body 3 end faces is by bluff body before changing 2 and back bluff body 3 end distance experimental verification gained results.
As shown in Figure 1, described xsect is the preceding bluff body 3 of blunt form and throat place or the flow speed stability position, throat front and back that back bluff body 4 is installed in Venturi tube (2).
Described two sensors 5,6 are piezoelectric transducer or capacitance type sensor.
Principle of work of the present utility model is as follows:
It is two bluff bodies of blunt form that xsect is housed in pipeline, in the symmetria bilateralis position of back bluff body sensor is housed respectively, and two sensors is connected with secondary instrument by circuit respectively.The Karman vortex street that the cycle staggering that is produced in preceding bluff body downstream by fluid comes off is inspired secondly under the bluff body effect of back and obtains stable more, the stronger secondary Karman vortex street of vibration, to reduce the metering lower limit of flowmeter.Externally insert the Venturi tube coaxial in the circular pipe with measuring tube, the rule of utilizing rate of flow of fluid in Venturi tube, to change with caliber, throat place or flow speed stability position, throat front and back will be installed in before and after two bluff bodies, improve signal to noise ratio (S/N ratio), reach and improve the purpose that the starting of oscillation flow of flowmeter was accurately measured and reduced to low flow velocity.

Claims (4)

1. two bluff body vortex shedding flow meters of a built-in venturi-type, it comprises pipeline (1), preceding bluff body (3), back bluff body (4), two sensors (5,6) and flowmeter secondary instrument (7); It is characterized in that: externally Yuan Xing pipeline (1) is built-in with Venturi tube (2), Venturi tube is equipped with perpendicular to conduit axis in (2), its xsect is the preceding bluff body (3) and the back bluff body (4) of blunt form, in bluff body (4) symmetria bilateralis position, back first sensor (5) and second sensor (6) are housed respectively, first sensor (5) is connected by the outer secondary instrument (7) of circuit (8) and pipeline respectively with second sensor (6).
2. the two bluff body vortex shedding flow meters of a kind of built-in venturi-type according to claim 1 is characterized in that: be 0.6DN~1.5DN apart between bluff body (3) and back bluff body (4) end face before described, wherein DN is the diameter of pipeline (1).
3. the two bluff body vortex shedding flow meters of a kind of built-in venturi-type according to claim 1 is characterized in that: described xsect is the preceding bluff body (3) of blunt form and throat place or flow speed stability position, throat front and back that back bluff body (4) is installed in Venturi tube (2).
4. the two bluff body vortex shedding flow meters of a kind of built-in venturi-type according to claim 1, it is characterized in that: described two sensors (5,6) are piezoelectric transducer or capacitance type sensor.
CN2010201058952U 2010-01-26 2010-01-26 Dual-bluff-body vortex flowmeter with built-in Venturi tube Expired - Fee Related CN201787975U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN2010201058952U CN201787975U (en) 2010-01-26 2010-01-26 Dual-bluff-body vortex flowmeter with built-in Venturi tube

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN2010201058952U CN201787975U (en) 2010-01-26 2010-01-26 Dual-bluff-body vortex flowmeter with built-in Venturi tube

Publications (1)

Publication Number Publication Date
CN201787975U true CN201787975U (en) 2011-04-06

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN2010201058952U Expired - Fee Related CN201787975U (en) 2010-01-26 2010-01-26 Dual-bluff-body vortex flowmeter with built-in Venturi tube

Country Status (1)

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CN (1) CN201787975U (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103630154A (en) * 2012-08-20 2014-03-12 杭州希玛诺光电技术有限公司 Measurement channel self-cleaning device used for immersion type instrument
CN105699690A (en) * 2016-01-28 2016-06-22 山东省科学院激光研究所 A vortex street wind speed sensor based on fiber gratings and an assembly method thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103630154A (en) * 2012-08-20 2014-03-12 杭州希玛诺光电技术有限公司 Measurement channel self-cleaning device used for immersion type instrument
CN105699690A (en) * 2016-01-28 2016-06-22 山东省科学院激光研究所 A vortex street wind speed sensor based on fiber gratings and an assembly method thereof
CN105699690B (en) * 2016-01-28 2018-09-28 山东省科学院激光研究所 A kind of vortex street air velocity transducer and its assemble method based on fiber grating

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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: 20110406

Termination date: 20140126