CN1256572C - Jet flow meter using vertical drain flow path and double outlet structure - Google Patents

Abstract

The present invention discloses a jet flowmeter using a vertical flow guide channel and a double outlet structure, which comprises a body, a jet element, a sensor and a secondary instrument, wherein an inlet of the body is connected with a shrinking tube, and an outlet is connected with an expanding tube. An ascending channel is arranged at the inlet in the body, and a descending channel is arranged at the outlet. The jet element is horizontally arranged on a plane above the body, an end cover is arranged above the jet element to fix the jet element on the body through screws, and a sensor is arranged in a feedback loop of the jet element and is connected with the secondary instrument outside the body through lines. In the present invention, when fluid passes through a jet plane, a jet attached wall induces the fluid to alternately oscillate and oscillation frequencies form a direct proportion with a flow rate of a jet nozzle. The present invention can operate under a low pipeline Reynolds number, can obtain a good signal-to-noise ratio, has a flow rate measuring limit lower than that of jet flowmeters with a planar structure, and has a good interference resisting capacitor.

Description

Adopt the fluidic flowmeter of vertical drain flow path and double outlet structure

Technical field

The present invention belongs to fluid metering equipment, particularly relates to a kind of fluidic flowmeter that adopts vertical drain flow path and double outlet structure.

Background technology

The appearance of fluidic flowmeter comes from the development of fluidics.Fluidics once developed quite rapid in the sixties and the seventies.According to the definition of N12PA (American National hydrodynamic force association), fluidics is that a kind of fluid dynamic phenomena that only utilizes is realized sensitivity, control, information processing, realize " with " reach " or " etc. the technology of function.

At present, the application of fluidic flowmeter in industry measurement is also not extensive, fluidic flowmeter is used for measuring the thick liquid of high viscosity, low discharge more abroad, or be used to the special occasions such as dirty fluid that measure some cold and hot fluid potpourris and easily produce the sensor fouling, also be useful on domestic gas meter or water meter; The application of fluidic flowmeter still belongs to rare at home.Existing fluidic flowmeter adopts the plane formula structure more, it comprises housing, two side wall surfaces, signal detection component and testing circuits, fluidic flowmeter is provided with the side wall surface of two symmetries in the flat space in housing, when power stream when nozzle is injected, because wall attachment effect can depend on one in two side wall surfaces arbitrarily, and enters corresponding feedback channel, acts on power stream, make it to switch and depend on another side wall surface, begun another feedback cycle.The generation fluid oscillating that so moves in circles obtains the fluid oscillating frequency by detecting the electric signal frequency, thereby records flow rate of fluid and flow indirectly.This fluidic flowmeter non mechanical movable, antijamming capability is better, is not subjected to the influence of external environment, and the metering lower limit is also low than most flowmeters, has its certain advantage in certain occasion.But owing to adopt the plane formula structure, aspect flow metering, still exist deficiency, be mainly reflected in following two aspects:

(1) measurable flux lower limit is low inadequately, because at Si Telaoha number (Strouhal Number) when being constant, the vibration frequency of fluid is directly proportional with flow rate of fluid, and the Si Telaoha number is relevant with Reynolds number, have only when Reynolds number within the specific limits the time, this special Laura number just is a constant, and this moment, the vibration frequency of fluid was directly proportional with the flow velocity of detected fluid.The structural limitations of plane formula its measurement range, when Reynolds number hour, viscous force has occupied dominant position gradually, makes oscillatory extinction; Caused that in addition the eddy current diffusion increases,, also weakened, also made oscillatory extinction by its velocity field that causes along with weakening of eddy current; Add the existence owing to mechanical vibration and upstream line flow pulsation interference, in this case, fluid is difficult to produce stable attached wall of jet and alternate oscillation, has greatly limited the range ability of flowmeter.

(2) to the fluidic flowmeter of plane formula structure, owing to adopt the single export structure form straight-through with the rear side pipeline, the intensity of feedback channel internal pressure signal a little less than, signal to noise ratio (S/N ratio) is lower, external environment can not suppress the interference of flowmeter internal flow, in secondary instrument, be difficult to it is removed, significantly the accuracy of influence measurement.

Summary of the invention

The object of the present invention is to provide a kind of fluidic flowmeter that adopts vertical drain flow path and double outlet structure that can obviously reduce the flow measurement lower limit, improve interference free performance.

For reaching above-mentioned purpose, the invention provides a kind of fluidic flowmeter that adopts vertical drain flow path and double outlet structure, it comprises:

1) flange, collapsible tube, extension tube, body, dividing plate, jet spare, end cap, sensor, boss, secondary instrument.Body is in inflow point and the collapsible tube welding that has flange, and weld with the extension tube that has another flange in the exit; Dividing plate, fluidic from bottom to up successively level overlay the plane, top of body, having end cap dividing plate and fluidic to be fixed on the body above the fluidic by screw; Boss is welded on the end cap, and sensor, is connected with extra-organismal secondary instrument with circuit on boss by screw retention;

2) at internal body, inflow point constitutes rising passway by horizontal run and vertical drain flow path, and the exit constitutes decline passway by "＞" shape vertical run and another horizontal run; The vertical drain flow path of body inflow point is coaxial with the import of the import of dividing plate, fluidic, and two outlets of the nose circle cylinder of "＞" shape vertical run in body exit and dividing plate, two outlets of fluidic are coaxial; Seal with gasket seal respectively between body, dividing plate, fluidic, the end cap; Through hole and the through hole on the fluidic that the probe of sensor passes on the end cap stretch in the feedback cavity of fluidic; Feedback cavity is the periphery that rotational symmetry is distributed in two sidewalls of fluidic with the center line of jet nozzle, two sidewalls are connected on the fluidic across feedback cavity by two dowels of self respectively, dividing plate with the corresponding position of dowel with corresponding shape hollow out, the space that hollow out is reserved on the feedback cavity of fluidic and the dividing plate forms the runner of fed-back fluid jointly, guarantees the height unanimity of whole feedback runner.

The useful effect that the present invention has is:

1) the present invention adopts the drain flow path structure perpendicular to fluidic in the fluidic porch, reduce the interference of the interior flow pulsation of upstream line to the fluidic interior flow field, make fluid can produce stable attached wall of jet and alternate oscillation under low reynolds number, the frequency of vibration is directly proportional with the flow velocity of jet nozzle.Improve its antijamming capability, thereby reduce the metering lower limit of fluidic flowmeter;

2) the present invention adopts the double outlet structure form perpendicular to fluidic in the fluidic exit, strengthens the pressure signal in the feedback cavity, increases the stability of the attached wall of jet, improves signal to noise ratio (S/N ratio) when reducing the metering lower limit.

Description of drawings

Fig. 1 is a structural principle synoptic diagram of the present invention;

Fig. 2 is a blast diagrammatic cross-section of the present invention;

Fig. 3 is the vertical view of fluidic among the present invention;

Fig. 4 is the vertical view of median septum of the present invention.

Embodiment

The invention will be further described below in conjunction with drawings and Examples.

As Fig. 1, Fig. 2, Fig. 3 and shown in Figure 4, the invention provides a kind of fluidic flowmeter that adopts vertical drain flow path and double outlet structure, it comprises:

1) flange 1, collapsible tube 2, extension tube 2 ', body 3, dividing plate 4, jet spare 5, end cap 6, sensor 7, screw 8, boss 9, secondary instrument 15; Body 3 is in inflow point and collapsible tube 2 welding that have flange 1, and weld with the extension tube 2 ' that has another flange 1 in the exit; Dividing plate 4, fluidic 5 from bottom to up successively level overlay the plane, top of body 3, having end cap 6 dividing plate 4 and fluidic 5 to be fixed on the body 3 above the fluidic 5 by screw 10; Boss 9 is welded on the end cap 6, and sensor 7 is fixed on the boss 9 by screw 8, and usefulness circuit 14 is connected with body 3 secondary instrument 15 outward;

2) in body 3 inside, inflow point constitutes rising passway by horizontal run 16 and vertical drain flow path 17, and the exit constitutes decline passway by "＞" shape vertical run 30 and another horizontal run 31; The vertical drain flow path 17 of body 3 inflow points is coaxial with the import 19 of the import 18 of dividing plate 4, fluidic 5, and two outlets 29 of the nose circle cylinder 32 of "＞" shape vertical run 30 in body 3 exits and dividing plate 4, two outlets 28 of fluidic 5 are coaxial; Between body 3 and the dividing plate 4, between dividing plate 4 and the fluidic 5, between fluidic 5 and the end cap 6 respectively with gasket seal 13, gasket seal 12 and gasket seal 11 sealings; Boss 9 is welded on the end cap 6, and through hole 33 and the through hole 25 on the fluidic 5 that the probe of sensor 7 passes on the end cap 6 stretch in the feedback cavity 23 of fluidic 5; Feedback cavity 23 is the periphery that rotational symmetry is distributed in two sidewalls 21 of fluidic 5 with the center line of jet nozzle 20, two sidewalls 21 are connected on the fluidic 5 across feedback cavity 23 by two dowels 24 of self respectively, dividing plate 4 with dowel 24 corresponding positions with corresponding shape hollow out, the space 26 that hollow out is reserved on the feedback cavity 23 of fluidic 5 and the dividing plate 4 forms the runners of fed-back fluid jointly, guarantees the height unanimity of whole feedback runner.

When measuring fluid flow, the fluidic flowmeter of this space structure is installed in the pipeline for the treatment of fluid measured, the horizontal run 16 of fluid process collapsible tube 2, rising passway, vertical drain flow path 17, the import 18 of dividing plate 4, the import 19 of fluidic 5, the jet plane at arrival fluidic 5 places; When fluid forms a jet via jet nozzle 20, because wall attachment effect, a fluid stream can optionally depend on any one in the sidewall 21 of two flarings, thereby be diverted into feedback cavity 23 from a small gangs of a fluid stream of sidewall 21 and make Medium Diffusion in the feedback channel, through the following side space of dowel 24 and the hollow space 26 on the dividing plate 4, return and act on power stream from control nozzle 27.When the flow of control nozzle 27 increases to maximal value by zero, be a complete periodic duty process, and affect power stream, make it be partial to another side wall surface, begun another feedback cycle.So move in circles, just have sub-fraction shunting vibration back and forth in two feedback cavity 23 in the power stream, fluid oscillating causes the fluctuation of feedback cavity 23 internal pressures to change, and Pressure Fluctuation Signal is accepted by column piezoeletric quartz sensor 7.In addition, also have the sub-fraction fluid to form eddy current, produce induced velocity, increase the attached wall stability of jet at the recess of spill splitter plate 22.Most fluids of power stream finally flow out fluidic flowmeter and enter fluid course through two outlets 28 of fluidic, two outlets 29 of dividing plate, "＞" shape vertical run 30, horizontal run 31 and the extension tube 2 ' of decline passway.

Theoretical research and experimental results demonstrate: in certain reynolds number range, the attached wall of jet brings out following definite relational expression between the width d of the frequency f of fluid oscillation and flow rate of fluid v of jet nozzle place and jet nozzle:

$f=\mathrm{St}\·\frac{v}{d}----\left(1\right)$

Wherein St is the Si Telaoha number, and for the fluidic flowmeter of certain version and dimensional parameters, the Si Telaoha number is the function of reynolds number Re, in Re=100～2 * 10 ⁵In the scope, St is a constant.

If the cross-sectional area of jet nozzle is A, pipeline flow is Q, then has

Q＝A·v (2)

The instrument coefficient K of secondary instrument 15 is:

K＝f/Q (3)

(1) and (2) substitution (3) is got:

K＝St/(A·d) (4)

For the fluidic flowmeter of given version and dimensional parameters, the cross-sectional area A of its jet nozzle, the width d of jet nozzle and Si Telaoha count St and can know, so the instrument coefficient K of flowmeter also can determine.

Because the frequency of the pressure surge in the feedback cavity 23 is identical with the fluid oscillation frequency, thereby just can obtain the fluid oscillation frequency by the frequency of detected pressures fluctuation signal, by formula (2) and (3) as can be seen, as long as accurately record the vibration frequency f of fluid, just can learn the flow velocity of detected fluid accurately, thereby reach the purpose of flow in the measuring channel.

With Pressure Fluctuation Signal in secondary instrument 15, amplify, processing such as filtering, shaping, obtain flow information.

Adopt the fluidic flowmeter of this space structure, can obtain signal to noise ratio (S/N ratio) preferably, have better anti-jamming capability and lower flow measurement lower limit.

Claims (1)

1. fluidic flowmeter that adopts vertical drain flow path and double outlet structure is characterized in that comprising:

1) flange (1), collapsible tube (2), extension tube (2 '), body (3), dividing plate (4), jet spare (5), end cap (6), sensor (7), boss (9), secondary instrument (15); Body (3) is in inflow point and collapsible tube (2) welding that has flange (1), and weld with the extension tube (2 ') that has another flange (1) in the exit; Dividing plate (4), fluidic (5) from bottom to up successively level overlay the plane, top of body (3), have end cap (6) dividing plate (4) and fluidic (5) to be fixed on the body (3) in fluidic (5) top by screw; Boss (9) is welded on the end cap (6), and on boss (9), the secondary instrument (15) outer with circuit (14) and body (3) is connected sensor (7) by screw retention;

2) in body (3) inside, inflow point constitutes rising passway by horizontal run (16) and vertical drain flow path (17), and the exit constitutes decline passway by "＞" shape vertical run (30) and another horizontal run (31); The vertical drain flow path (17) of body (3) inflow point is coaxial with the import (19) of the import (18) of dividing plate (4), fluidic (5), and two outlets (29) of the nose circle cylinder (32) of "＞" shape vertical run (30) in body (3) exit and dividing plate (4), two outlets (28) of fluidic (5) are coaxial; Body (3), dividing plate (4), fluidic (5), end cap seal with gasket seal respectively between (6); Through hole (33) and the through hole (25) on the fluidic (5) that the probe of sensor (7) passes on the end cap (6) stretch in the feedback cavity (23) of fluidic (5); Feedback cavity (23) is the periphery that rotational symmetry is distributed in two sidewalls (21) of fluidic (5) with the center line of jet nozzle (20), two sidewalls (21) are connected on the fluidic (5) across feedback cavity (23) by two dowels (24) of self respectively, dividing plate (4) with the corresponding position of dowel (24) with corresponding shape hollow out, the space (26) that the last hollow out of the feedback cavity (23) of fluidic (5) and dividing plate (4) is reserved forms the runner of fed-back fluid jointly, guarantees the height unanimity of whole feedback runner.

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