CN102353406B - Flowmeter with middle through-hole movable throttling element connected with elastic membranes or bellows - Google Patents

Abstract

The invention discloses a flowmeter with a middle through-hole movable throttling element connected with elastic membranes or a bellows, which belongs to the throttling flowmeter in the automatic detection technical field; the patent 'a middle through-hole movable throttling element flowmeter' depends on the thrust of the movable throttling element, and does not like a fixed throttling element which measures the flow according to the flow differential pressure, so a pressure pipe can be dispensed, the flowmeter is applicable to measuring small calibers and dirty liquids, the isolation, the pressure-bearing, the support and other functions of the flowmeter are all respectively realized through different components, and the integral structure is more complicated. The flowmeter adopts the elastic membranes or the bellows to be connected with the middle through-hole movable throttling element, the isolation, the pressure-bearing, the support and other functions are realized independently by the elastic membranes or the bellows, the integral structure of the flowmeter is greatly simplified, not only are all the advantages of the through-hole movable throttling element obtained, but also a plurality of performances are improved, and the invention makes the through-hole movable throttling element flowmeter which is a novel meter be more easily popularized and used.

Description

The flowmeter of middle through-hole movable throttling element connected with elastic membranes or corrugated tube

Technical field

The present invention relates to a kind of instrument that in the Automatic Measurement Technique field, realizes flow detection.

Background technology

At present, the flow measurement that utilizes Throttle Principle to implement is still most widely used, and employed restriction device major part is the fixation type throttle element, and small part is dynamic throttling element.In the flowmeter that utilizes Throttle Principle to make, differential pressure flowmeter uses the fixation type throttle element, and target type meter and spinner-type flowmeter use dynamic throttling element.Fixation type throttle element abacus, nozzle and Venturi tube commonly used, they use with a long history, and test figure is complete, and product is standardization, so claim that again they are " standard restriction device ".In measurement, orifice plate, nozzle and Venturi tube fixedly mount in pipeline, and fluid flows through from their middle through-hole; The dynamic throttling element of target type meter or spinner-type flowmeter is disk target or the rotor that is suspended in pipeline central authorities, and this dynamic throttling element of disk target or rotor does not have middle through-hole, and fluid flows through from the annular gap of disk target or rotor and pipeline enclosure.Between fixation type throttle element and the differential pressure gauge connecting pipe is arranged, be unsuitable for measuring dirty medium.In order both to keep every advantage of orifice plate, nozzle and Venturi tube, break away from again all inconvenience that connecting pipe brings, in " dynamic throttling element flowmeter of middle through-hole " (patent No. 200910072808.X), adopted first the dynamic throttling element of the middle through-hole of orifice plate, nozzle or Venturi tube profile, in this flowmeter, detected fluid to the thrust of dynamic throttling element be with the flow of fluid one to one.Above-mentioned flowmeter adopts nonmetallic resilient ring to bring the isolation detected fluid, and detected fluid acts on the pressure on the elastic ring belt, then comes balance by the equilibrium liquid that this pressure can be delivered to watchcase.In addition, the dynamic throttling element in this flowmeter is supported by a pair of moving sets, the friction force of moving sets had both affected measuring accuracy, again so that the manufacturing of flowmeter and debugging complicated.

Summary of the invention

Because above-mentioned middle through-hole dynamic throttling element flowmeter structure is complicated, is unfavorable for promoting the use of of this new flowmeter, therefore, need the simpler middle through-hole dynamic throttling element flowmeter of a kind of structure of development.

The present invention is that the technical scheme that adopts of its technical requirement of solution is as follows: shown in Figure of description, the flowmeter of development is the flowmeter of a kind of middle through-hole movable throttling element connected with elastic membranes or corrugated tube, belongs to the throttle type flow instrumentation in the Automatic Measurement Technique field; Each need connect a flexible sheet or corrugated tube the dynamic throttling element two ends of middle through-hole; When dynamic throttling element connects circular flexible sheet, the inner edge of the flexible sheet that the dynamic throttling element entrance side connects and dynamic throttling element inlet end are tightly connected, its outer rim and front tube are tightly connected, the inner edge of the flexible sheet that the dynamic throttling element outlet side connects and dynamic throttling element endpiece are tightly connected, and its outer rim and rear end pipe are tightly connected; When dynamic throttling element connects corrugated tube, right side one end and the dynamic throttling element inlet end of the corrugated tube that the dynamic throttling element entrance side connects are tightly connected, its left side one end and front tube are tightly connected, left side one end and the dynamic throttling element endpiece of the corrugated tube that the dynamic throttling element outlet side connects are tightly connected, its right side one end and rear end pipe are tightly connected, and the weight of dynamic throttling element is supported by the elastic sheet metal suspender belt; Casing frame and makes this three be rigidly connected to fix two distances between the end pipe between front tube and rear end pipe; Above-mentioned being tightly connected forms a fluid from the inflow of front end tube inlet, then flows through the dynamic throttling element middle through-hole, the leak free flow channel that then flows out from the rear end pipe outlet; In the occasion of measuring dirty fluid, except said structure, also use two and front tube (1), the resilient seal endless belt (15) of the non-metallic material cylindraceous of the bores such as rear end pipe (3) and dynamic throttling element (2), stop up to prevent from greater than the accessibility zone of the fluid to be measured of this bore, producing, the inlet end of one end of a resilient seal endless belt (15) and dynamic throttling element (2) is tightly connected, the other end and front tube (1) are tightly connected, the endpiece of one end of another resilient seal endless belt (15) and dynamic throttling element (2) is tightly connected, the other end and rear end pipe (3) are tightly connected, equilibrium liquid need be full of in the enclosure space that is called forward horizontal stand chamber (16) that between flexible sheet that a resilient seal endless belt (15) and dynamic throttling element (2) entrance side connect or corrugated tube, forms, also equilibrium liquid need be full of in the enclosure space that is called back balance chamber (17) that between flexible sheet that another resilient seal endless belt (15) and dynamic throttling element (2) outlet side connect or corrugated tube, forms.When measuring flow, the thrust that fluid acts on the dynamic throttling element has definite corresponding relation with the flow that flows through its middle through-hole, by power throw-over gear and attached sensor thereof fluid is acted on thrust on the dynamic throttling element and be converted to corresponding electrical quantity and change, subsequent process circuit changes this electrical quantity and amplifies, linearization, V/I conversion or the further processing that shows.In the flowmeter of measuring dirty fluid, forward horizontal stand chamber equilibrium liquid pressure is identical with dynamic throttling element entrance resilient seal endless belt detected fluid wall pressure, and back balance chamber equilibrium liquid pressure is identical with dynamic throttling element elasticity of export seal band detected fluid wall pressure.After taking abovementioned technology, because the inside and outside pressure at both sides of two resilient seal endless belt are identical, not affected by radial force, therefore less demanding to itself physical strength, can adopt the non-metallic elastic material manufacturing, to reduce its elastic force that axial displacement applies to dynamic throttling element.

The invention has the beneficial effects as follows, identical with existing patent " dynamic throttling element flowmeter of middle through-hole ", the flowmeter of middle through-hole movable throttling element connected with elastic membranes or corrugated tube still utilizes Throttle Principle in measurement, thereby is subject to the impact of extraneous measuring condition unlike vortex shedding flow meter; Because Venturi tube, nozzle and orifice plate are used as dynamic throttling element, cancel the connecting pipe that differential pressure flowmeter is denounced most again, thereby be difficult for stopping up, and can reduce difficulty of construction; When particularly using Venturi tube as dynamic throttling element, flowmeter has also that fluid resistance losses is little, tenure of use is long, precision is higher, the also advantage such as difficult obstruction of the part of the trunk line except connecting pipe, can be applicable in the flow measurement of pipe with small pipe diameter and dirty fluid.Existing patent " dynamic throttling element flowmeter of middle through-hole " is compared with the flowmeter of middle through-hole movable throttling element connected with elastic membranes or corrugated tube, the former buffer fluid leans on the resilient seal endless belt of non-metallic material, bear detected fluid pressure and rely on the rigid seal housing, support dynamic throttling element and rely on a pair of moving sets, and the latter can be with isolation, pressure-bearing, supporting three functions is independently realized by flexible sheet, perhaps will isolate, two functions of pressure-bearing are realized by corrugated tube, and support function is realized by the metal suspender belt that does not produce friction force, thereby the latter's structure is simpler, it is easier to make, Installation and Debugging are more convenient, cost performance and precision are higher.

Description of drawings

Fig. 1 is the structure principle chart of first embodiment of the present invention.

Fig. 2 is the structure principle chart of second embodiment of the present invention.

Fig. 3 is the structure principle chart of the 3rd embodiment of the present invention.

Fig. 4 is the structure principle chart of the 4th embodiment of the present invention.

Fig. 5 is the structure principle chart of the 5th embodiment of the present invention.

Fig. 6 is the structure principle chart of the 6th embodiment of the present invention.

1. front tube among the figure, 2. Venturi tube, 3. rear end pipe, 4. casing frame, 5. foil gauge, 6. strained handling circuit, 7. detection semi-girder, 8. balanced cantilever beam, 9. gear frame, 10. anterior elastic membrane sheet, 11. Descemets membrane sheets, 12. sheet metal suspender belts, 13. front corrugated tube, 14. rear corrugated tubes, 15. resilient seal endless belt, 16. the forward horizontal stand chamber, back balance chambers 17..

Embodiment

In following six embodiment, in order to reduce fluid resistance losses and to prevent the dirt gathering, dynamic throttling element adopts Venturi tube 2, in some application scenario, Venturi tube 2 also can be replaced by orifice plate or nozzle, and other parts of flowmeter then keep the original structure form constant.

Embodiment one

In the embodiment of Fig. 1, use the ripple flexible sheet 10,11 of two circular belt edge ripples, circular anterior elastic membrane sheet 10 is connected with exit seal with the entrance of Venturi tube 2 respectively with the inner edge of Descemets membrane sheet 11, and anterior elastic membrane sheet 10 is tightly connected with front tube 1 and rear end pipe 3 respectively with the outer rim of Descemets membrane sheet 11.Casing frame 4 is rigidly connected each other with front tube 1 and rear end pipe 3, thereby can fix two distances between the end pipe, and the effect that miscellaneous part is installed is in the above arranged.Detecting semi-girder 7 is installed on casing frame 4 with balanced cantilever beam 8, detect on the semi-girder 7 and post foil gauge 5, on balanced cantilever beam 8, do not paste foil gauge, the purpose that balanced cantilever beam 8 is set be balance detection semi-girder 7 produce be unfavorable for Venturi tube 2 axially movable additional moments.When flow is crossed Venturi tube 2, the flow of fluid is larger, fluid is also larger to the thrust of Venturi tube 2, Venturi tube 2 is detecting this thrust on semi-girder 7 and the balanced cantilever beam 8 by gear frame 9 again, detect semi-girder 7 and produce the strain corresponding with thrust, produce differential change so that be attached to respectively the foil gauge resistance of the positive and negative strain regions of semi-girder, the electric bridge of the differential change of this resistance in strained handling circuit 6 further exported the voltage signal corresponding with thrust after the processing with amplifier.

Detected fluid acts on being analyzed as follows of thrust on the Venturi tube 2 and measured flux Relations Among: Venturi tube 2 is placed on the horizontal straight tube road, like this, just only need to consider static energy when the potential energy of research Venturi tube 2 front and back fluids changes, therefore can draw according to fluid mechanics

$\frac{p_1}{\mathrm{\&gamma;}}-\frac{{\mathrm{<figure-callout\; id="2"\; label="p"\; filenames="110705205425.png,110705205546.png"\; state="\{\{state\}\}">p</figure-callout>}}_2}{\mathrm{\&gamma;}}=\mathrm{\&xi;}\frac{v^2}{2g}$

P in the formula ₁, p ₂---Venturi tube 2 forward and backward fluid effects static pressure thereon;

The severe of γ---detected fluid;

ξ---resistance coefficient, it and Venturi tube 2 shapes, fluid viscosities etc. are relevant;

G---acceleration of gravity;

V---flow is crossed the flow velocity of Venturi tube 2 middle through-holes.

Obviously, p ₁-p ₂Multiply by the long-pending A in effective cross section of Venturi tube 2, namely obtain detected fluid and act on thrust F on the Venturi tube 2.Venturi tube 2 effective cross sections are long-pending can be calculated as follows

$A=\frac{1}{4}\mathrm{\&pi;}{D}^2-\frac{1}{4}\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="110705205425.png,110705205546.png"\; state="\{\{state\}\}">d</figure-callout>}}^2$

D in the formula---external pipe internal diameter;

D---Venturi tube 2 middle through-hole diameters.

Long-pending directly the calculating by its physical dimension in the effective cross section of Venturi tube 2 is based on following consideration: different from the calculating of the useful area of the limited flexible sheet in edge, Venturi tube 2 is integrated movings, and the effective cross section is long-pending needn't consider edge effect.Because with respect to flat diaphragm, the ripple flexible sheet 10 of belt edge ripple, the stiffness coefficient of 11 pairs of axial centre displacements is much smaller, in measuring process, the displacement of Venturi tube 2 is extremely small again, also to consider simultaneously when flow is crossed Venturi tube 2 and before and after it, will produce pressure reduction, suitably select flexible sheet 10,11 useful area, fluid pressure difference is at two flexible sheets 10, the extra-push model that produces on 11, to offset two flexible sheets 10,11 major part even whole bounces because of axially micro-displacement generation, therefore detected fluid to the thrust F of Venturi tube 2 mainly by two semi-girders 7,8 bounce balance, two flexible sheets 10, the impact of the 11 bounce thrust F that produce along the pipeline axial displacement can be ignored.

Comprehensive above two formulas can get

$F=A(p_1-p_2)=\frac{1}{8}\mathrm{\&pi;}(D^2-d^2)\mathrm{\&xi;}\frac{v^2\mathrm{\&gamma;}}{g}$

Or $v=\sqrt{\frac{8\mathrm{gF}}{\mathrm{\&pi;}(D^2-d^2)\mathrm{\&xi;\&gamma;}}}$

Can get the expression formula of tested volume flow Q according to following formula

$Q=\frac{1}{4}\mathrm{\&pi;}{d}^{2}v=\sqrt{\frac{\mathrm{\&pi;<figure-callout\; id="4"\; label="g\; d"\; filenames="110705205425.png,110705205546.png"\; state="\{\{state\}\}">g</figure-callout>}{d}^{}{}^4}{2(D^2-d^2)\mathrm{\&xi;\&gamma;}}}\&CenterDot;\sqrt{F}=C\sqrt{F}$

In following formula, after the parameters of detected fluid and Venturi tube physical dimension had been determined, C was constant, so the volume flow Q of detected fluid is directly proportional with the square root of thrust F.But because the composition item ξ of C can not obtain by theoretical the derivation, therefore can only determine the C value by the method for flowmeter being carried out experimental calibration.

Embodiment two

In the embodiment of Fig. 2, can find out that present embodiment is structurally substantially identical with the embodiment of Fig. 1, only has following 2 differences.At first, in Fig. 2, replaced the ripple flexible sheet 10,11 of two belt edge ripples among Fig. 1 with two circular planar diaphragms 10,11, the inner edge of the anterior elastic membrane sheet 10 on plane is connected with the inlet seal of Venturi tube 2, and its outer rim and front tube 1 are tightly connected; The inner edge of the Descemets membrane sheet 11 on plane is connected with the exit seal of Venturi tube 2, and its outer rim and rear end pipe 3 are tightly connected; And processed a pit corresponding with effective diaphragm area in each end pipe and planar diaphragm 10, the 11 relative sides, so that Venturi tube 2 has the vertically nargin of move left and right.Its two, foil gauge 5 is sticked on the frontal plane diaphragm 10, cancelled detection semi-girder 7, balanced cantilever beam 8 and gear frame 9, simplified the structure of flowmeter.

In the present embodiment, Venturi tube 2 suffered thrust F comprise because of what the fluid throttling produced and act directly on thrust F on the Venturi tube 2 ₁With the thrust F of indirectly-acting on Venturi tube 2 that produces at two planar diaphragms 10,11 useful area because of fluid pressure difference ₂Because F ₁With F ₂Equal big or small corresponding with measured flux of numerical value, these two power sum F are again only by two planar diaphragms 10,11 bounce institute balance simultaneously, therefore stick on the size that foil gauge output signal on the frontal plane diaphragm 10 can obtain measured flux by measurement.

Embodiment three

In the embodiment of Fig. 3, use two U-shaped corrugated tubes 13,14, the front end of front corrugated tube 13 and front tube 1 are tightly connected, and its rear end is connected with the inlet seal of Venturi tube 2; The front end of rear corrugated tube 14 is connected with the exit seal of Venturi tube 2, and its rear end and rear end pipe 3 are tightly connected.The weight of Venturi tube 2 is supported by two elastic sheet metal suspender belts 12, and foil gauge 5 sticks on the sheet metal suspender belt 12.Sheet metal suspender belt 12 is made by very thin elastic sheet metal, and its stiffness coefficient along pipeline axial is very little, and bounce that its distortion produces is also very little, thereby can think that the suffered thrust F of Venturi tube 2 is only by the bounce balance of two corrugated tubes.But the deflection deformation of sheet metal suspender belt 12 is consistent with the axial deformation of corrugated tube, and therefore, the output signal that sticks on the foil gauge 5 on the sheet metal suspender belt 12 by measurement can obtain the size of measured flux.

Embodiment four

In the embodiment of Fig. 4, use two ends that the sealing U-shaped corrugated tube 13,14 at the end is arranged, at the bottom of the sealing of each corrugated tube, process the hole of a corresponding size with Venturi tube 2 bores.Be less than corrugated tube among the embodiment three with the corrugated tube 13 at the perforate sealing end, 14 axial rigidity coefficient, thereby can be used for the more measurement of low discharge.The front end of front corrugated tube 13 and front tube 1 are tightly connected, and the hole on its rear end sealing end is connected with the inlet seal of Venturi tube 2; Hole at the front end sealing end of rear corrugated tube 14 is connected with the exit seal of Venturi tube 2, and its rear end and rear end pipe 3 are tightly connected.The weight of Venturi tube 2 is supported by an elastic sheet metal suspender belt 12, and foil gauge 5 sticks on the sheet metal suspender belt 12.The reason same with embodiment three, can think that the suffered thrust F of Venturi tube 2 is only by two corrugated tubes 13,14 bounce balance, the deflection deformation of sheet metal suspender belt 12 and corrugated tube 13,14 axial deformation are consistent, therefore, the output signal that sticks on the foil gauge 5 on the sheet metal suspender belt 12 by measurement can obtain the size of measured flux.

More than flowmeter among four embodiment only be suitable for measuring cleaner liquid and gas, when measuring dirty fluid, can adopt the scheme of embodiment five or embodiment six.

Embodiment five

The embodiment of Fig. 5 is structurally substantially identical with embodiment among Fig. 1, but in order to prevent that dirt from gathering flexible sheet 10,11 with end pipe 1, in the space between 3, affect the normal operation of flowmeter, two and end pipe 1 have been used, 3 and the resilient seal endless belt 15 of the non-metallic material cylindraceous of the bore such as Venturi tube 2, one end of two resilient seal endless belt 15 is connected with entrance or the exit seal of Venturi tube 2 respectively, the other end is tightly connected with front tube 1 or rear end pipe 3 respectively, two resilient seal endless belt 15 and two flexible sheets 10, need be full of equilibrium liquid in the enclosure space that is called forward horizontal stand chamber 16 and back balance chamber 17 that forms respectively between 11.Consider that the amount of contraction of liquid under pressure is very little, the radial expansion amount of resilient seal endless belt 15 when detected fluid pressure changes is very little, and by equilibrium liquid this pressure is delivered to the flexible sheet 10,11 of metal material, by flexible sheet 10,11 pressure-bearings.Therefore during measurement, two resilient seal endless belt 15 equilibrium liquid wall pressure are identical with the detected fluid wall pressure, not affected by radial force, and less demanding to itself physical strength can adopt the non-metallic elastic material manufacturing.Because two resilient seal endless belt 15 are to be made by the very little non-metallic elastic material of stiffness coefficient, in measuring process, the axial displacement of Venturi tube 2 is extremely small again, so resilient seal endless belt 15 can be ignored the impact of thrust F along the flexible of pipeline axial.Detected fluid still mainly by two semi-girders 7,8 bounce balance, sticks on size that the output signal that detect foil gauge 5 semi-girder 7 on can obtain measured flux by measurement to the thrust F of Venturi tube 2.

Embodiment two and embodiment four also can be used in the measurement occasion of the dirty fluid of stolen goods behind the resilient seal endless belt 15 that uses non-metallic material.

Embodiment six

The embodiment of Fig. 6 is structurally substantially identical with embodiment three, but in order to prevent that dirt from gathering corrugated tube 13, in 14 the U-shaped ripple ditch, affect the normal operation of flowmeter, two and end pipe 1 have been used, 3 and the resilient seal endless belt 15 of the non-metallic material cylindraceous of the bore such as Venturi tube 2, the left end of two resilient seal endless belt 15 respectively with two corrugated tubes 13,14 left part flat segments inner seal connects, the right-hand member of two resilient seal endless belt 15 respectively with two corrugated tubes 13,14 right part flat segments inner seals connect, two resilient seal endless belt 15 and two corrugated tubes 13, two seal cavity domestic demands that form respectively between 14 are full of equilibrium liquid.Two resilient seal endless belt 15 that so connect and two corrugated tubes 13,14 have consisted of two integrated assemblies, it is more convenient that kit form can make the installation of flowmeter make, and the entering of these two assemblies and Venturi tube 2, outlet and front and back ends pipe 1,3 the mode that is tightly connected are identical with embodiment three.Consider that the amount of contraction of liquid under pressure is very little, the radial expansion amount of resilient seal endless belt 15 when detected fluid pressure changes is very little, and can this pressure be delivered to the corrugated tube 13,14 of metal material by equilibrium liquid, by corrugated tube 10,11 pressure-bearings.Therefore during measurement, two resilient seal endless belt 15 equilibrium liquid wall pressure are identical with the detected fluid wall pressure, not affected by radial force, and less demanding to itself physical strength can adopt the non-metallic elastic material manufacturing.Because two resilient seal endless belt 15 are to be made by the very little non-metallic elastic material of stiffness coefficient, in measuring process, the axial displacement of Venturi tube 2 is extremely small again, so resilient seal endless belt 15 can be ignored the impact of thrust F along the flexible bounce variation that produces of pipeline axial.Therefore, identical with embodiment three, can think that the suffered thrust F of Venturi tube 2 is only by the bounce balance of two corrugated tubes, the axial bounce of sheet metal suspender belt 12 can be ignored equally, but its deflection deformation is consistent with the axial deformation of corrugated tube, therefore, the output signal that sticks on the foil gauge 5 on the sheet metal suspender belt 12 by measurement can obtain the size of measured flux.

Claims (1)

1. the flowmeter of a middle through-hole movable throttling element connected with elastic membranes or corrugated tube, belong to the throttle type flow instrumentation in the Automatic Measurement Technique field, it is characterized in that: each need connect a flexible sheet (10,11) or corrugated tube (13,14) dynamic throttling element of middle through-hole (2) two ends; When dynamic throttling element (2) connects circular flexible sheet (10,11), the inner edge of the flexible sheet (10) that dynamic throttling element (2) entrance side connects and dynamic throttling element (2) inlet end are tightly connected, its outer rim and front tube (1) are tightly connected, the inner edge of the flexible sheet (11) that dynamic throttling element (2) outlet side connects and dynamic throttling element (2) endpiece are tightly connected, and its outer rim and rear end pipe (3) are tightly connected; Dynamic throttling element (2) connects corrugated tube (13,14) time, right side one end of the corrugated tube (13) that dynamic throttling element (2) entrance side connects and dynamic throttling element (2) inlet end are tightly connected, its left side one end and front tube (1) are tightly connected, left side one end of the corrugated tube (14) that dynamic throttling element (2) outlet side connects and dynamic throttling element (2) endpiece are tightly connected, its right side one end and rear end pipe (3) are tightly connected, and the weight of dynamic throttling element (2) is supported by elastic sheet metal suspender belt (12); Casing frame (4) is positioned between front tube (1) and the rear end pipe (3), and makes this three be rigidly connected to fix two distances between the end pipe; Above-mentioned being tightly connected forms a fluid from the inflow of front tube (1) entrance, then flows through dynamic throttling element (2) middle through-hole, the leak free flow channel that then flows out from rear end pipe (3) outlet; In the occasion of measuring dirty fluid, except said structure, also use two and front tube (1), the resilient seal endless belt (15) of the non-metallic material cylindraceous of the bores such as rear end pipe (3) and dynamic throttling element (2), stop up to prevent from greater than the accessibility zone of the fluid to be measured of this bore, producing, the inlet end of one end of a resilient seal endless belt (15) and dynamic throttling element (2) is tightly connected, the other end and front tube (1) are tightly connected, the endpiece of one end of another resilient seal endless belt (15) and dynamic throttling element (2) is tightly connected, the other end and rear end pipe (3) are tightly connected, equilibrium liquid need be full of in the enclosure space that is called forward horizontal stand chamber (16) that between flexible sheet that a resilient seal endless belt (15) and dynamic throttling element (2) entrance side connect or corrugated tube, forms, also equilibrium liquid need be full of in the enclosure space that is called back balance chamber (17) that between flexible sheet that another resilient seal endless belt (15) and dynamic throttling element (2) outlet side connect or corrugated tube, forms.

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