阅读说明：本技术 一种防噪声干扰的超声波流量测量装置 (Ultrasonic flow measuring device capable of preventing noise interference ) 是由 李卫东 徐显明 王保民 杨豫森 姚国鹏 陶继业 于 2020-12-29 设计创作，主要内容包括：本发明公开了一种防噪声干扰的超声波流量测量装置,被测流体上游管道通过三通接头与缓振结构以及下游管道相连,流体经缓振结构消除上游干扰噪声后进入下游,经整流分配器后进入换能器及显示装置测量,通过对流体流动中由于外部原因产生的超声杂音进行反射和吸收,消除干扰,为超声波流量计提供有利的测量环境,获取高精度和稳定的流量数据。(The invention discloses an ultrasonic flow measuring device for preventing noise interference, wherein an upstream pipeline of a measured fluid is connected with a slow vibration structure and a downstream pipeline through a tee joint, the fluid enters the downstream after the upstream interference noise of the fluid is eliminated by the slow vibration structure, enters an energy converter and a display device for measurement after passing through a rectifying distributor, and the interference is eliminated by reflecting and absorbing ultrasonic noise generated due to external reasons in the fluid flow, so that a favorable measuring environment is provided for an ultrasonic flow meter, and high-precision and stable flow data are obtained.)

1. The utility model provides an ultrasonic flow measuring device of noise control interference which characterized in that, is including installing ultrasonic flowmeter (8) and the buffering structure on the pipeline that is surveyed, the buffering structure includes slow vibration room (5), be provided with damping membrane (4) in slow vibration room (5), be filled with air or inert gas in slow vibration room (5).

2. An ultrasonic flow measurement device against noise interference according to claim 1, wherein the vibration attenuating structure is installed in a direction close to the noise source.

3. An ultrasonic flow measurement device for preventing noise interference according to claim 1, wherein the vibration damping structure is connected to the measured fluid pipeline by a tee joint (2), the measured fluid pipeline comprises an upstream pipeline (1) and a downstream pipeline (9), and three ports of the tee joint (2) are respectively connected with the upstream pipeline (1), the downstream pipeline (9) and the vibration damping chamber (5).

4. An ultrasonic flow measuring device for preventing noise interference according to claim 1, wherein the damping chamber (5) is provided with a switching valve (6).

5. An ultrasonic flow measurement device for noise interference prevention according to claim 1, characterised in that the damping membrane (4) is a movable piston or a fixed flexible plate.

6. An ultrasonic flow measurement device for noise interference prevention according to claim 1 or 5, characterized in that the damping membrane (4) is provided with a coating of damping material.

7. An ultrasonic flow measuring device for preventing noise interference according to claim 1, wherein the rectifying distributor (7) is installed on the upstream pipeline of the ultrasonic flow meter (8), the rectifying distributor (7) comprises a plate body, the shape of the plate body is the same as the shape and the size of the longitudinal section of the pipeline for measuring the fluid, and a plurality of through holes (13) for the fluid to flow through are formed on the plate body.

8. An ultrasonic flow measurement device for noise immunity according to claim 1, wherein the ultrasonic flow meter (8) comprises a first transducer (11), a second transducer (12) and a display device for measuring and displaying the flow of the measured fluid.

Technical Field

The invention belongs to the technical field of flow measurement, and particularly relates to an ultrasonic flow measurement device capable of preventing noise interference.

Background

In the modern industrial field, pressure, flow and temperature are regarded as three important detection parameters for industrial automation, and the flow meter is widely applied to the aspects of metallurgy, chemical engineering, natural gas transportation, petroleum transportation, civil water meters and the like. The demand for flow metering, whether industrial or commercial, is constantly increasing.

The traditional flowmeter performs flow measurement based on the functional relation between the resistance characteristic and the flow speed of fluid in the flowing process, such as a Venturi flowmeter, an orifice plate flowmeter and the like, and has the similar characteristics that the fluid is in direct contact with a measurement structure, the pressure loss is large, and the measurement range is small. The most serious disadvantages of this type of flowmeter are the sensitivity to wear of the firmware and the low measurement accuracy. With the development of ultrasonic technology and sensor technology, acoustic measurement technology is increasingly widely used. The ultrasonic flow meter has no movable parts, is non-contact, digitalized and electronized, and generally has higher measurement precision, better linearity, wider range ratio, high reliability and simple maintenance in performance, so the ultrasonic flow meter gradually enters various measurement and metering fields.

However, in different application places, the ultrasonic flowmeter is affected by the roughness of the inner wall of the upstream straight pipe section, gas components, the length of the upstream straight pipe section, the flow state of fluid upstream of the flowmeter, noise interference of a water pump and the like, airflow pulsation and the like in the use process, so that the measurement accuracy is affected. In order to overcome the external influence, although a filter is adopted to overcome part of interference, the effect is limited, and therefore other means are needed to reduce noise interference so as to improve the measurement accuracy.

Disclosure of Invention

The invention provides an ultrasonic flow measuring device for preventing noise interference, which eliminates interference by reflecting and absorbing ultrasonic noise generated by external reasons in fluid flow, provides a favorable measuring environment for an ultrasonic flow meter and acquires high-precision flow data.

In order to achieve the above object, the ultrasonic flow measuring device for preventing noise interference according to the present invention includes an ultrasonic flow meter mounted on a pipe to be measured, and a vibration damping structure, where the vibration damping structure includes a vibration damping chamber, a vibration damping film is disposed in the vibration damping chamber, and the vibration damping chamber is filled with air or inert gas.

Further, the vibration damping structure is installed in a direction close to the noise source.

Furthermore, the damping structure is connected to the fluid pipeline to be measured through a three-way joint, the fluid pipeline to be measured comprises an upstream pipeline and a downstream pipeline, and three interfaces of the three-way joint are respectively connected with the upstream pipeline, the downstream pipeline and the damping chamber.

Furthermore, a switch valve is arranged on the vibration damping chamber.

Further, the damping diaphragm is a movable piston or a fixed flexible plate.

Furthermore, a damping material coating is arranged on the damping diaphragm.

Furthermore, a rectifying distributor is installed on an upstream pipeline of the ultrasonic flowmeter and comprises a plate body, the shape of the plate body is the same as the shape and the size of the longitudinal section of the fluid pipeline to be measured, and a plurality of through holes through which fluid flows are formed in the plate body.

Further, the ultrasonic flowmeter comprises a first transducer, a second transducer and a display device, and is used for measuring and displaying the measured fluid.

Compared with the prior art, the invention has at least the following beneficial technical effects:

the invention provides an ultrasonic measuring device for preventing noise interference, wherein a damping film and a damping chamber form a damping system, vibration wave energy acts on the damping film after noise is transmitted by utilizing the compressibility of gas, the vibration wave energy is transmitted to the gas in the damping chamber through the microspur movement or vibration of the damping film, the gas is compressed and converted into heat energy, and the energy dissipation of noise sound waves is realized. By arranging the noise elimination mechanism, ultrasonic noise mixed by other sound sources such as pulsation of fluid flow, fluid interception, a pump and the like is reflected and absorbed, interference is eliminated, a favorable measurement environment is provided for the ultrasonic flowmeter, and accurate flow data is obtained. Compared with the existing ultrasonic flowmeter, the ultrasonic flowmeter has stronger anti-interference capability, and effectively improves the measurement precision and stability.

Furthermore, the damping structure is installed in the direction close to the noise source, and the noise reduction effect is improved.

Furthermore, the switch valve is arranged on the vibration damping chamber, so that the vibration damping chamber can be conveniently inflated or deflated.

Furthermore, a damping material coating is arranged on the damping diaphragm, so that the damping effect is further improved.

Furthermore, a rectification distributor is installed at the upper stream of the ultrasonic flowmeter, and comprises a plate body, wherein the shape of the plate body is the same as the shape and the size of the longitudinal section of the measured fluid pipeline, a plurality of through holes for flowing fluid are formed in the plate body, the elbow of the measured fluid pipeline is subjected to vortex rectification, and the requirement of installing a straight section before the ultrasonic flowmeter is shortened.

Drawings

FIG. 1 is a schematic structural view of an ultrasonic flow measuring apparatus for preventing noise interference according to the present invention;

FIG. 2 is a sectional view taken along line A-A of FIG. 1;

FIG. 3 is a schematic diagram of an ultrasonic flow meter measurement;

fig. 4 is a schematic diagram of an ultrasonic flow meter.

In the drawings: 1. the ultrasonic flow meter comprises an upstream pipeline, 2, a three-way joint, 3, a mounting flange, 4, a damping membrane, 5, a damping chamber, 6, a switch valve, 7, a rectifying distributor, 8, an ultrasonic flow meter, 9, a downstream pipeline, 10, a through hole, 11, a first transducer, 12, a second transducer, 13 and a through hole.

Detailed Description

In order to make the objects and technical solutions of the present invention clearer and easier to understand. The present invention will be described in further detail with reference to the following drawings and examples, wherein the specific examples are provided for illustrative purposes only and are not intended to limit the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified. In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The main principle of the invention for preventing noise interference is to utilize the characteristics of sound wave transmission reflection and damping absorption, and a vibration reduction film with reflection and absorption functions is arranged in the main direction of noise sound wave transmission to reflect and absorb the transmission energy of the noise sound wave.

Example 1

Referring to fig. 1, an ultrasonic flow measuring device for preventing noise interference includes a measuring fluid pipe 1, a three-way joint 2, a mounting flange 3, a damping membrane 4, a damping chamber 5, a switching valve 6, a rectifying distributor 7, and an ultrasonic flow meter 8, where the ultrasonic flow meter 8 includes two transducers and a display screen.

The measuring fluid pipeline comprises an upstream pipeline 1 and a downstream pipeline 9, the upstream pipeline 1 is connected with a vibration damping structure and the downstream pipeline 9 through a tee joint 2, an ultrasonic flowmeter 8 is installed on the downstream pipeline 9, fluid enters the downstream pipeline 9 after upstream interference noise is eliminated through the vibration damping structure, and enters the ultrasonic flowmeter 8 for measurement after passing through a rectifying distributor 7. When the downstream direction of the fluid flow is interfered by a noise source, the device of the same type can also be arranged to damp the downstream noise. The upstream side of the measuring fluid conduit 1 communicates with the inlet of the three-way joint 2.

The vibration damping structure comprises a vibration damping chamber 5, a vibration damping membrane 4 and a switch valve 6, wherein the vibration damping chamber 5 and the upstream part of the measuring fluid pipeline 1 are coaxially arranged; the vibration damping chamber 5 is installed at the first outlet of the three-way joint 2 through the installation flange 3, and the vibration damping film 4 can be a piston type flexible plate which can freely move along the inner wall of the vibration damping chamber 5 or can be fixedly installed, and has a larger damping coefficient. Filling air or inert gas into the vibration damping chamber 5 through the switch valve 6, wherein the filling pressure is approximately equal to the fluid pressure, and specifically, the fluid pressure is plus or minus 20 percent; the function of the elastic compression space is to balance the fluid pressure and form an elastic compression space. Extreme accidents need to be considered for selecting the gas, namely, the gas leaks to the main flow working medium when the damping film is damaged, and the accident expansion is not caused. The noise from the fluid upstream propagates along the fluid, and the sound wave reaches the damping membrane 4 and is reflected and absorbed by the damping membrane 4.

The damping diaphragm 4 and the damping chamber 5 form a damping system, the compressibility of gas is utilized, after noise is transmitted, vibration wave energy acts on the damping diaphragm, the gas is transmitted to the damping chamber 5 through the microspur movement or vibration of the damping diaphragm 4, and the gas is compressed and converted into heat energy, so that the energy dissipation of noise sound waves is realized.

Preferably, a damping material coating can be additionally arranged on the vibration damping film 4, so that the vibration damping effect is further improved.

The downstream pipeline 9 is provided with a rectifying distributor 7, and the rectifying distributor 7 is used for rectifying the vortex caused by the elbow of the measured fluid pipeline and shortening the requirement of installing a straight section in front of the ultrasonic flowmeter 8. The rectifier distributor 7 may not be installed depending on the requirements of installation space and the actual situation of the site.

Referring to fig. 2, the rectifying distributor 7 includes a plate body having the same shape and size as the longitudinal section of the fluid pipeline to be measured, and a plurality of circular through holes 13 are formed in the plate body.

The fluid in the fluid pipeline 1 to be measured is a liquid or gas single-phase medium, and no phase change is generated in the fluid pipeline and the flowmeter. The measured fluid pipeline 1 is a round pipe or a square pipe.

Referring to fig. 3, the ultrasonic flow meter 8 includes a first transducer 11, a second transducer 12, and a display device for measuring and displaying the flow of the measured fluid.

The ultrasonic flowmeter is divided into the following parts according to the measurement principle: a propagation velocity difference method (simply referred to as a velocity difference method), a doppler effect method, a noise method, a correlation method, and the like, and the velocity difference method and the doppler effect method are commonly used. The Doppler method is used for determining the flow of fluid by measuring the ultrasonic Doppler frequency shift scattered by a scatterer in inhomogeneous fluid by using the acoustic Doppler principle, and is suitable for measuring the flow of two-phase flow containing suspended particles, bubbles and the like. The differential method comprises the following steps: the basic principle of the direct time difference method, the phase difference method and the frequency difference method is that the flow velocity of the fluid is reflected by measuring the difference between the forward and backward propagation velocities of the ultrasonic pulse, wherein the frequency difference method and the time difference method overcome the error caused by the change of the sound velocity along with the temperature of the fluid, have higher accuracy and are widely adopted. Ultrasonic gas flow meters typically use a differential method. The differential method is mainly applied to the measurement of single-phase fluid.

The following briefly introduces the basic measurement principle of the ultrasonic gas flowmeter by taking a time difference method as an example:

on the measuring tube section of the instrument, a pair of ultrasonic transducers are obliquely arranged: a first ultrasonic transducer 11 and a second transducer 12 which alternately transmit and receive ultrasonic pulses, as shown in fig. 3. In fig. 3: c is the speed of sound in the fluid medium; v is the flow rate of the fluid medium in the pipeline; l is the length of the sound path; theta is an included angle between the transducer and the axis of the pipeline; d is the diameter of the pipeline.

On the sound path L, the propagation velocity of the ultrasonic wave is the superposition of the sound velocity and the flow velocity component. Forward and backward flow directionsTime of flight t₁、t₂Respectively as follows:

the propagation time t in the forward and backward directions is measured₁、t₂The flow velocity V can then be calculated:

because of the measured forward and backward propagation times t₁、t₂Incorporating inherent electroacoustic delays τ produced by circuits, cables, transducers, etc₁、τ₂Since the influence is to be subtracted, equation (3) can be rewritten as:

the actual fluid flow velocity has flow velocity distribution on the pipeline loading surface due to friction and viscosity action of the pipe wall and the fluid inside, the measured flow velocity V of the single-channel ultrasonic flowmeter on the central line is actually the linear average velocity on the inner diameter of the pipeline section, and the surface average flow velocity V of the pipeline section is required for measuring the flow_mThey are not equal. According to the theory of fluid mechanics, when the reynolds number is greater than 4000, the fluid is in a turbulent state, and a kinetic factor K (a function of the reynolds number Re of the pipeline, which can be obtained by actual measurement in the process of calibrating the flowmeter) exists between the linear average flow velocity and the surface average flow velocity, that is:

so as to obtain the instantaneous volume flow Q_{Instant heating device}：

In continuous measurement, only Q to be measured is required one by one_{Instant heating device}The value is integrated with time, so that the accumulated flow Q in any time period can be obtained_{Tired of}After the volume flow is compensated by pressure and temperature, the mass flow Q can be obtained_{Quality of food}：

In the formula: rho₀Is the density of the gas medium in a standard state; p₀And P is the pressure in the standard state and the actual state respectively; t0, T is the temperature in the standard and actual states respectively; and Z is the gas compression coefficient. As can be seen from the expressions (4) and (6), t is the sound time₁、t₂Is the key to flow measurement, at parameters D, L, θ, τ₁、τ₂After K is determined, only t needs to be accurately measured₁、t₂Can accurately obtain the flow velocity V and the instantaneous flow Q in the pipeline_{Instant heating device}Further, the accumulated flow rate Q can be obtained_{Tired of}Mass flow rate Q_{Quality of food}。

The schematic diagram of the ultrasonic flowmeter is shown in FIG. 4: the first transducer 11 and the second transducer 12 are respectively installed on two sides of a fluid line and are at a certain distance from each other, ultrasonic emission mainly comprises a master control oscillator, a switcher and the like, ultrasonic emission is achieved by a sawtooth wave voltage generator through signal processing of the master control oscillator, a sending pulse signal required by the transducers is obtained, the first ultrasonic transducer is driven to emit an ultrasonic signal, and when the transducers are in resonance due to the adoption of an inductance-capacitance matching circuit, piezoelectric ceramics generate enough vibration energy and send out a high-power ultrasonic signal. The function of the switcher is that the transceiving control circuit controls the transmitting and receiving of pulse signals, after ultrasonic signals transmitted by the first transducer 11 are transmitted to the second transducer 12, the switch of the switcher controls the second transducer 12, the second transducer 12 obtains received ultrasonic signals, the received waveforms and the transmitted waveforms pass through the receiving amplifier and the output gate to be subjected to logic processing of a digital circuit through a peak detector, a differential amplifier and the like through the receiving amplifier and the output gate, time signals are obtained, data processing and calculation are carried out, and finally flow data are obtained and displayed.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.