阅读说明：本技术 一种热对流式电化学振动传感器 (Heat convection type electrochemical vibration sensor ) 是由 杨大鹏 陈恒 王小欢 孙郡泽 鞠宸浩 田宝凤 郑凡 于 2021-09-13 设计创作，主要内容包括：本发明公开了一种热对流式电化学振动传感器,包括：工作介质、设有内部中心流道及外部环形流道的密封腔、热对流驱动单元、速度测量单元及信号处理电路。其中,工作介质完全填充于密封腔的内部；热对流驱动单元位于密封腔的底部,且正对内部中心流道；速度测量单元位于密封腔的内部；信号处理电路分别与热对流驱动单元及速度测量单元连接。本发明利用设有内部中心流道及外部环形流道的密封腔密封工作介质,利用热对流驱动单元驱动工作介质形成稳定的环形流动,并利用工作介质运动速度的变化反映外界加速度的大小,从而避免了橡胶膜的使用,改善了传感器的长期稳定性,且能够测量直流加速度。(The invention discloses a heat convection type electrochemical vibration sensor, which comprises: the device comprises a working medium, a sealing cavity provided with an inner central flow passage and an outer annular flow passage, a heat convection driving unit, a speed measuring unit and a signal processing circuit. Wherein, the working medium is completely filled in the sealed cavity; the heat convection driving unit is positioned at the bottom of the sealing cavity and is opposite to the internal central flow passage; the speed measuring unit is positioned inside the sealed cavity; the signal processing circuit is respectively connected with the heat convection driving unit and the speed measuring unit. The invention utilizes the sealing cavity provided with the inner central flow passage and the outer annular flow passage to seal the working medium, utilizes the thermal convection driving unit to drive the working medium to form stable annular flow, and utilizes the change of the movement speed of the working medium to reflect the magnitude of the external acceleration, thereby avoiding the use of a rubber film, improving the long-term stability of the sensor and being capable of measuring the direct current acceleration.)

1. A heat convective electrochemical vibration sensor, comprising:

a working medium;

a sealing cavity provided with an inner central flow passage and an outer annular flow passage and used for sealing the working medium; the working medium completely fills the sealed cavity;

the heat convection driving unit is positioned at the bottom of the sealed cavity, is opposite to the internal central flow passage, and is used for heating a working medium at the internal central flow passage;

the speed measuring unit is positioned in the sealed cavity and used for measuring the movement speed of the working medium to obtain a speed measuring signal;

and the signal processing circuit is respectively connected with the thermal convection driving unit and the speed measuring unit and is used for obtaining a vibration sensing signal according to the speed measuring signal.

2. A heat convection type electrochemical vibration sensor as in claim 1, wherein the working medium is an electrolyte having self redox reaction capability.

3. A heat convective electrochemical vibration sensor of claim 1, wherein said sealed cavity comprises an outer shell and an inner core;

the outer shell is positioned on the periphery of the inner core, and an annular gap is reserved between the outer shell and the periphery of the inner core and used for forming the external annular flow passage;

the inner core is two arched isolating bodies with the bottom surfaces oppositely arranged; and a vertical gap is reserved between the two arched blocking bodies with the bottom surfaces oppositely arranged and is used for forming the internal central flow passage.

4. A heat convection electrochemical vibration sensor of claim 3, wherein the heat convection drive unit is located at a bottom of the housing.

5. A convectional electrochemical vibration sensor according to claim 4, wherein said convectional drive unit is a heater.

6. A heat convection electrochemical vibration sensor of claim 3, wherein the velocity measurement unit is located in a central position of the inner central flow channel.

7. A heat convection electrochemical vibration sensor as in claim 6, wherein the velocity measurement unit is an electrochemical transducer.

8. A heat convection electrochemical vibration sensor as in claim 7, wherein the electrochemical transducer is comprised of four porous inert metal electrodes.

9. A heat convection type electrochemical vibration sensor of claim 8, wherein the four porous inert metal electrodes are arranged in an anode-cathode-anode or cathode-anode-cathode manner; the anode is connected with a power supply of the signal processing circuit, and the cathode is connected with a signal processing part of the signal processing circuit.

10. A heat convection electrochemical vibration sensor as in claim 9, wherein the signal processing portion of the signal processing circuit comprises:

the differential amplification module is connected with the cathode of the electrochemical transducer and is used for differentially amplifying the speed measurement signal;

and the filtering processing module is connected with the differential amplification module and is used for filtering the speed measurement signal after differential amplification to obtain a vibration sensing signal.

Technical Field

The invention relates to the field of vibration sensing devices, in particular to a heat convection type electrochemical vibration sensor.

Background

The vibration sensor is used as a sensor for detecting vibration or impact, and is widely applied to the fields of structural vibration measurement and seismic measurement. The electromagnetic vibration sensor, the capacitance vibration sensor, the piezoelectric vibration sensor, the optical fiber vibration sensor, the electrochemical vibration sensor and the like are common in the market. The magnetic moving coil type vibration sensor has simple structure and lower price, but has lower precision. The capacitive vibration sensor has good low-frequency performance, but is large in size and high in price. The piezoelectric vibration sensor has wide acceleration detection frequency band and better precision, but has low sensitivity and is not suitable for steady-state measurement occasions. The optical fiber type vibration sensor has high sensitivity, but the working principle is complex, and the requirement on the production process is high.

The electrochemical sensor has the advantages of small volume, high sensitivity, large dynamic range, wide frequency band, good low-frequency performance, low cost, batch production and the like, is gradually applied to the fields of seismology, structural monitoring, navigation and the like, and is used for the electrochemical sensor of seismic exploration, such as an MTSS geophone developed and produced by Russian R-sensors company, a CME series long-period seismometer product for long-period natural seismic monitoring and the like.

The existing electrochemical vibration sensor is generally sealed by adopting rubber membranes at two ends of a cavity, the elastic force of the rubber membranes is used as a spring of a vibration pickup unit, electrolyte is used as a mass body, the motion resistance of the electrolyte is used as system damping to form a second-order elastic system of mass/spring/damping, an electrochemical transducer measures the motion speed of the electrolyte, and the low-frequency expansion of the sensor is realized by adopting a force balance feedback technology outside the electrochemical vibration sensor.

Therefore, the prior art has the following disadvantages: 1) when the rubber film is used for a long time, the rubber film is influenced by heat, oxygen, ozone and chemical substances, particularly by strong oxidation of iodine/potassium iodide electrolyte used in an electrochemical sensor, so that the elasticity of the rubber is reduced, and the performance index of the sensor is deviated; 2) the iodine content in the working medium of the sensor is low, and the concentration of the working medium is reduced and the sensitivity of the sensor is reduced after the iodine content reacts with the rubber film; 3) and the method cannot be used for measuring direct current acceleration.

Disclosure of Invention

It is an object of the present invention to provide a heat convection type electrochemical vibration sensor to improve the long term stability of the sensor.

In order to achieve the purpose, the invention provides the following scheme:

a heat convective electrochemical vibration sensor, the sensor comprising:

a working medium;

a sealing cavity provided with an inner central flow passage and an outer annular flow passage and used for sealing the working medium; the working medium completely fills the sealed cavity;

the heat convection driving unit is positioned at the bottom of the sealed cavity, is opposite to the internal central flow passage, and is used for heating a working medium at the internal central flow passage;

the speed measuring unit is positioned in the sealed cavity and used for measuring the movement speed of the working medium to obtain a speed measuring signal;

and the signal processing circuit is respectively connected with the thermal convection driving unit and the speed measuring unit and is used for obtaining a vibration sensing signal according to the speed measuring signal.

Optionally, the working medium is an electrolyte with self-oxidation-reduction reaction capability.

Optionally, the sealed cavity comprises an outer shell and an inner core;

the outer shell is positioned on the periphery of the inner core, and an annular gap is reserved between the outer shell and the periphery of the inner core and used for forming the external annular flow passage;

the inner core is two arched isolating bodies with the bottom surfaces oppositely arranged; and a vertical gap is reserved between the two arched blocking bodies with the bottom surfaces oppositely arranged and is used for forming the internal central flow passage.

Optionally, the thermal convection driving unit is located at a bottom of the housing.

Optionally, the thermal convection driving unit is a heater.

Optionally, the speed measuring unit is located at a central position of the inner center flow passage.

Optionally, the speed measurement unit is an electrochemical transducer.

Optionally, the electrochemical transducer is comprised of four porous inert metal electrodes.

Optionally, the four porous inert metal electrodes are arranged in an anode-cathode-anode or cathode-anode-cathode manner; the anode is connected with a power supply of the signal processing circuit, and the cathode is connected with a signal processing part of the signal processing circuit.

Optionally, the signal processing portion of the signal processing circuit includes:

the differential amplification module is connected with the cathode of the electrochemical transducer and is used for differentially amplifying the speed measurement signal;

and the filtering processing module is connected with the differential amplification module and is used for filtering the speed measurement signal after differential amplification to obtain a vibration sensing signal.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects:

the invention provides a heat convection type electrochemical vibration sensor, which comprises: the device comprises a working medium, a sealing cavity provided with an inner central flow passage and an outer annular flow passage, a heat convection driving unit, a speed measuring unit and a signal processing circuit. Wherein, the working medium is completely filled in the sealed cavity; the heat convection driving unit is positioned at the bottom of the sealing cavity and is opposite to the internal central flow passage; the speed measuring unit is positioned inside the sealed cavity; the speed measuring unit is used for measuring the movement speed of the working medium in the sealed cavity and obtaining a speed measuring signal; the signal processing circuit is respectively connected with the heat convection driving unit and the speed measuring unit and used for obtaining a vibration sensing signal according to the speed measuring signal. The invention utilizes the sealing cavity provided with the inner central flow passage and the outer annular flow passage to seal the working medium, utilizes the thermal convection driving unit to drive the working medium to form stable annular flow, and utilizes the change of the movement speed of the working medium to reflect the magnitude of the external acceleration, thereby avoiding the use of a rubber film, improving the long-term stability of the sensor, reducing the types of packaging materials, simplifying the packaging mode of the sensor, and being capable of measuring the direct current acceleration.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic diagram of the internal structure of a heat convection type electrochemical vibration sensor of the present invention;

fig. 2 is a flow chart of the operation of the heat convection type electrochemical vibration sensor of the present invention.

Description of the symbols: the device comprises a working medium-1, a speed measuring unit-2, a sealed cavity-3 and a thermal convection driving unit-4.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It is an object of the present invention to provide a heat convection type electrochemical vibration sensor to improve the long term stability of the sensor.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

As shown in fig. 1, the present invention provides a heat convection type electrochemical vibration sensor comprising: the device comprises a working medium 1, a speed measuring unit 2, a sealed cavity 3, a thermal convection driving unit 4 and a signal processing circuit.

Specifically, the sealed cavity 3 is provided with an inner central flow passage and an outer annular flow passage; the working medium 1 is completely filled and sealed inside the sealed chamber 3.

The thermal convection driving unit 4 is positioned at the bottom of the sealed cavity 3 and is opposite to the internal central flow channel; the thermal convection driving unit 4 is used for heating the working medium 1 at the inner center flow passage.

The speed measuring unit 2 is positioned inside the sealed cavity 3; the speed measuring unit 2 is used for measuring the moving speed of the working medium 1 to obtain a speed measuring signal.

The signal processing circuit is respectively connected with the thermal convection driving unit 4 and the speed measuring unit 2; the signal processing circuit is used for obtaining a vibration sensing signal according to the speed measuring signal and is also used for supplying power to the speed measuring unit 2 and the heat convection driving unit 4.

Further, the working medium 1 is an electrolyte having a self-redox reaction capability. In this embodiment, the working medium 1 is iodine-potassium iodide electrolyte, wherein the concentration of potassium iodide is 1-4mol/L, and the concentration of iodine is 1-4 mmol/L.

Preferably, the sealed cavity 3 comprises an outer shell and an inner core. The outer shell is located on the periphery of the inner core, and an annular gap is reserved between the outer shell and the periphery of the inner core and used for forming the external annular flow passage. The inner core is two bow-shaped isolating bodies with the bottom surfaces oppositely arranged. And a vertical gap is reserved between the two arched blocking bodies with the bottom surfaces oppositely arranged and is used for forming the internal central flow passage.

Further, the thermal convection driving unit 4 is located at the bottom of the housing.

Preferably, the thermal convection driving unit 4 is a heater.

Further, the speed measuring unit 2 is located at the center of the inner center flow passage.

Preferably, the speed measuring unit 2 is an electrochemical transducer.

Further, the electrochemical transducer is composed of four porous inert metal electrodes.

In the embodiment, the four porous inert metal electrodes are arranged in an anode-cathode-anode or cathode-anode-cathode manner; the anode is connected with a power supply of the signal processing circuit, and the cathode is connected with a signal processing part of the signal processing circuit.

During operation, the anode of the electrochemical transducer is supplied with an external voltage and the cathode acts as a measuring electrode. The working medium 1 is subjected to reversible oxidation-reduction reaction on the surface of the cathode/anode under the action of external voltage of the electrochemical transducer to cause the change of nearby current, and the movement speed of the working medium 1 can be reversely deduced by measuring the change of the current flowing through the cathode/anode.

Preferably, the signal processing portion of the signal processing circuit includes a differential amplification module and a filtering processing module.

Specifically, the differential amplification module is connected with a cathode of the electrochemical transducer; the differential amplification module is used for carrying out differential amplification on the speed measurement signal.

The filtering processing module is connected with the differential amplifying module; and the filtering processing module is used for filtering the speed measurement signal after differential amplification to obtain a vibration sensing signal.

According to the invention, the signal processing part of the signal processing circuit is used for carrying out differential amplification and filtering processing on the speed measurement signal output by the cathode of the electrochemical transducer, so that the vibration sensing signal output by the sensor is linearly related to the movement speed or the acceleration of the working medium 1, and the magnitude of the external acceleration is reflected.

Fig. 2 is a working flow diagram of the heat convection type electrochemical vibration sensor of the present invention, as shown in fig. 2, in the working process, the heat convection driving unit 4 heats the working medium 1, the electrochemical vibration sensor reaches a stable state under the combined action of the heating of the heat convection driving unit 4 and the heat dissipation of the outer annular flow channel, and the temperature of the working medium 1 in the inner central flow channel is slightly higher than the temperature of the working medium 1 in the outer annular flow channel, so that the working medium 1 forms a stable annular flow between the inner central flow channel and the outer annular flow channel of the sealed cavity 3 under the combined action of gravity, buoyancy and friction. When the external acceleration exists, the density difference exists between the working media 1 in the inner central flow passage and the outer annular flow passage, the movement speed of the working media 1 flowing annularly is influenced to change, the speed measuring unit 2 measures the speed change of the working media 1, and the external acceleration is calculated through the signal processing circuit.

Specifically, the method of resolving the external acceleration by the signal processing circuit is as follows:

because in the sealed cavity, the working medium meets the Navier-Stokes equation of the incompressible fluid under the action of temperature and external acceleration:

wherein the content of the first and second substances,representing the flow rate of the working medium in the sealed cavity, P representing the pressure, ρ representing the density of the working medium, μ representing the viscosity coefficient of the working medium,representing the ambient acceleration and t representing time.

Specifically, the calculation formulas of the density ρ of the working medium and the viscosity coefficient μ of the working medium are respectively:

where ρ is_wIs the density of water, mu_wIs the viscosity coefficient of water, c_iIn the context of ion concentration within the working medium, k is the ion species, T is the temperature, and A and B represent the coefficients of different salt species within the working medium, respectively (which can be retrieved in the relevant chemical literature).

The heat convection velocity of the working medium can be calculated according to laminar flow, and can be obtained by multiple calculation modes under the condition that the inner boundary of the sealed cavity has no slippageAndthe functional relationship of (a).

ρ_hThe density of the heated working medium, g is the gravity acceleration, a is the external acceleration, and f is the friction force applied to the working medium with the volume V in the center flow channel, and is equal to beta x V. Wherein, beta is a proportionality coefficient, and v is the movement speed of the working medium.

When no acceleration exists outside, the working medium with the volume V in the internal central flow channel of the sealed cavity is influenced by buoyancy, gravity and friction force to form stable natural convection, and the movement speed of the working medium is V₀And carrying out stress analysis on the working medium with the volume V to obtain:

ρ_hVg+βv₀＝ρVg

when the outside has acceleration, the motion speed of the working medium changes, and the measured motion speed of the working medium is assumed to be v₁And then, carrying out stress analysis on the working medium with the volume V to obtain:

and (3) simultaneously connecting stress analysis formulas under two conditions of external acceleration and external no acceleration to obtain:

after the processing, the relationship between the movement speed of the working medium in the internal central flow passage and the external acceleration is obtained as follows:

the output current I of the speed measuring unit and the flow speed of the working mediumBecause of the fixed corresponding relation, the relation between the output current and the external acceleration can be further obtained:

wherein, I_oAnd I₁Respectively velocity is v_oAnd v₁The output current of time, gamma, is the proportionality coefficient of the output current to the movement speed of the working medium.

The signal processing circuit converts the current output into voltage output based on the output function relation, and enables the output voltage and the external acceleration or the integral (namely the vibration speed) of the external acceleration to be in a linear relation.

The invention adopts the sealing cavity provided with the inner central flow passage and the outer annular flow passage to seal the working medium, and utilizes the heat convection driving unit to drive the working medium to form stable annular flow so as to realize the induction of the external acceleration. Compared with the traditional electrochemical sensor which uses the elastic force of the rubber membrane as a vibration pickup unit and is limited by the elastic limit of the rubber membrane, the effect of measuring the direct current acceleration is poor, and the method can be used for measuring the direct current acceleration. And because the use of a rubber film is avoided, the types of packaging materials are reduced, so that the packaging mode of the sensor can be further simplified, and the miniaturization and product integration of the sensor are facilitated. Furthermore, the problems of deviation of performance indexes and sensitivity reduction of the sensor caused by the fact that the rubber membrane is reduced in elasticity and the working medium concentration is reduced due to the fact that the rubber membrane reacts with the working medium, external chemical substances and the like can be avoided, and the stability of the sensor in long-term working is improved.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to assist in understanding the core concepts of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.