Ground liquid level monitoring terminal based on liquid medium type ultrasonic waves

Abstract

The invention belongs to the technical field of liquid level monitoring, and particularly relates to a ground liquid level monitoring terminal based on liquid medium type ultrasonic waves, which consists of an ultrasonic transmitter, a receiver, a liquid medium type coupling device, a control unit and an external bracket, the ultrasonic transmitter is used for transmitting ultrasonic signals, the receiver is used for receiving the ultrasonic signals reflected from the liquid level, the liquid medium type coupling device can ensure that contact and coupling are formed between the ultrasonic transmitter and the receiver and liquid to be detected, the control signals comprise a signal processing module and a calculation module, and the external support is used for protecting components in the terminal device. According to the invention, the specially designed liquid medium type coupling device is in direct contact with the liquid to be measured, and the absolute height of the liquid level can be calculated by accurately measuring the round-trip time of the ultrasonic waves and combining the known sound velocity and the geometric parameters of the coupling device.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid level monitoring, and particularly relates to a ground liquid level monitoring terminal based on liquid-medium ultrasonic waves. Background Art

[0002] In the current technical field of liquid level monitoring, common ground liquid level monitoring methods mainly include float type, pressure type, and radar type, etc. Among them, the float type liquid level gauge reflects the liquid level change through the up and down floating of the float. Although its structure is simple, it is easily affected by factors such as medium density and temperature, and the maintenance cost is relatively high; the pressure type liquid level gauge measures according to the relationship between liquid static pressure and liquid level height, and is suitable for liquids with low viscosity and no corrosion, but its adaptability to high-pressure, high-temperature or strongly corrosive environments is poor; the radar type liquid level gauge uses electromagnetic waves for non-contact measurement, and has the advantages of high precision and long-distance measurement, but its cost is high, and there are limitations in the measurement of some liquid surfaces (such as covered with foam).

[0003] However, the above technical solutions are limited in application under different medium characteristics and environmental conditions. Especially in liquids with high temperature, high pressure, corrosion or a large amount of suspended matter, their measurement accuracy and stability are easily affected, and the maintenance cost is high, and some technical solutions are relatively complex in installation, debugging and subsequent operations, which is not conducive to rapid deployment and remote monitoring. Therefore, the present invention provides a ground liquid level monitoring terminal based on liquid-medium ultrasonic waves, which can provide an economic, efficient, strong environmental adaptability, and simple installation and maintenance liquid level monitoring solution. Summary of the Invention

[0004] The present invention provides a ground liquid level monitoring terminal based on liquid-medium ultrasonic waves to solve the technical problems of the existing liquid level monitoring terminal with low accuracy, high maintenance cost, and relatively complex installation, debugging and subsequent operations, which is not conducive to rapid deployment and remote monitoring.

[0005] To achieve the above object, the technical solutions adopted by the present invention are as follows: A ground liquid level monitoring terminal based on liquid-medium ultrasonic waves is composed of an ultrasonic transmitter, a receiver, a liquid-medium coupling device, a control unit, and an external bracket. The ultrasonic transmitter is responsible for emitting short-pulse ultrasonic waves into the liquid. The receiver is used to receive the ultrasonic signal reflected from the liquid surface. The liquid-medium coupling device can ensure the contact and coupling between the ultrasonic transmitter and the receiver and the liquid to be measured. The control signal includes a signal processing module and a calculation module. The external bracket is used to protect the components inside the terminal device.

[0006] Further, the signal processing module is responsible for processing the ultrasonic signal received by the receiver and extracting the round-trip time; the calculation module calculates the absolute height of the liquid surface according to the known sound speed and the geometric parameters of the liquid-medium coupling device.

[0007] Compared with the prior art, the present invention has the following beneficial effects:

[0008] (1) The terminal device of the present invention includes an ultrasonic transmitter and a receiver. Both are in direct contact with the liquid to be measured through a specially designed liquid-medium coupling device. By accurately measuring the round-trip time of ultrasonic waves and combining the known sound speed and the geometric parameters of the coupling device, the absolute height of the liquid level can be calculated.

[0009] (2) The single-chip microcomputer main control circuit of the ultrasonic sensor of the present invention processes the ultrasonic waveform through the variational mean-field algorithm in the sparse state, improving its measurement accuracy and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a structural diagram of the ground liquid level monitoring terminal based on liquid-medium ultrasonic of the present invention;

[0011] Figure 2 is an internal structural diagram of the ultrasonic sensor of the liquid level monitoring terminal of the present invention;

[0012] Figure 3 is a single-chip microcomputer control circuit diagram of the ultrasonic sensor of the liquid level monitoring terminal of the present invention;

[0013] Figure 4 is a transmitting circuit diagram of the ultrasonic sensor of the liquid level monitoring terminal of the present invention;

[0014] Figure 5 is a receiving circuit diagram of the ultrasonic sensor of the liquid level monitoring terminal of the present invention;

[0015] Figure 6 is a temperature compensation circuit diagram of the transmitting circuit of the ultrasonic sensor of the liquid level monitoring terminal of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0017] Such as Figure 1As shown, the ground liquid level monitoring terminal based on liquid - medium ultrasonic consists of an ultrasonic transmitter, a receiver, a liquid - medium coupling device, a control unit, and an external bracket. The ultrasonic transmitter is responsible for emitting short - pulse ultrasonic waves into the liquid. The receiver is used to receive the ultrasonic signal reflected from the liquid surface. The liquid - medium coupling device can ensure contact and coupling between the ultrasonic transmitter and receiver and the liquid to be measured. The control signal includes a signal processing module and a calculation module. The external bracket is used to protect the components inside the terminal device.

[0018] (1) Ultrasonic transmitter: Responsible for emitting a series of short - pulse ultrasonic waves into the liquid. These ultrasonic pulses are characterized by high frequency and short duration, which can ensure the accuracy and stability of the measurement.

[0019] (2) Receiver: Used to receive the ultrasonic signal reflected from the liquid surface. The receiver needs to have high sensitivity to ensure that weak reflected signals can be accurately captured.

[0020] (3) Liquid - medium coupling device: It is a key component in the present invention. It can ensure good contact and coupling between the ultrasonic transmitter and receiver and the liquid to be measured. The coupling device is usually made of corrosion - resistant and high - pressure - resistant materials to ensure normal operation in harsh environments.

[0021] (4) Control unit: Includes a signal processing module and a calculation module. The signal processing module is responsible for processing the ultrasonic signal received by the receiver and extracting useful information (such as round - trip time). The calculation module calculates the absolute height of the liquid surface based on the known sound speed and the geometric parameters of the coupling device.

[0022] (5) External bracket: Used to protect the components inside the terminal device and prevent them from being interfered with and damaged by the external environment. The external bracket is usually made of strong and corrosion - resistant materials.

[0023] During operation, the ultrasonic transmitter emits a series of short - pulse ultrasonic waves into the liquid. These ultrasonic waves propagate inside the liquid to the liquid surface and then are reflected to form a reflected wave. After the reflected wave is received by the receiver, the signal processing module processes it to extract the round - trip time. Then, the calculation module calculates the absolute height of the liquid surface based on the known sound speed and the geometric parameters of the coupling device.

[0024] When ultrasonic waves propagate from the upper medium to the lower medium, due to the large difference in density between the two media, the propagation direction of the ultrasonic waves changes drastically at the interface. Part of them is reflected back, and part of them refracts into the adjacent medium.

[0025] The specific process by which the calculation module calculates the absolute height of the liquid surface based on the known sound speed and the geometric parameters of the liquid - medium coupling device is as follows:

[0026] (1) When ultrasonic waves propagate from the upper medium to the lower medium, the densities of the upper and lower media are ρ 1 and ρ 2 respectively, and the sound wave propagation speeds in them are ν 1 and ν 2 respectively. The incident angle is α, the refraction angle is β, and the intensities of the reflected wave and the refracted wave are IF and IR respectively. There are:

[0027]

[0028] (2) When the ultrasonic wave is vertically incident, that is, α = β = 0 to the lower medium, the reflectivity is calculated by the following formula:

[0029] (3) The liquid level height According to the ultrasonic wave propagation time collected, combined with its propagation speed in the air, it can be obtained and thus the absolute height of the liquid surface can be calculated.

[0030] The liquid medium coupling device is also provided with an ultrasonic sensor. The terminals of the ultrasonic sensor are connected to two upper interfaces of the liquid medium coupling device, so that the ultrasonic radiation surface is placed on the upper surface of the bottom of the liquid medium coupling device to ensure contact and coupling between the ultrasonic transmitter and receiver and the liquid to be measured.

[0031] The main modules integrated inside the ultrasonic sensor include an ultrasonic transmitting and receiving circuit, a single-chip microcomputer main control circuit, and a temperature compensation circuit. For the specific circuit diagram, see Figures 3 - 6 . The single-chip microcomputer main control circuit uses an intelligent algorithm for waveform processing. Considering the signal sparsity, the variational mean field algorithm in the sparse state is adopted.

[0032] The specific model of the variational mean field algorithm in the sparse state is as follows: For the ultrasonic received signal y ∈ C M , there is the following model:

[0033] y = Φα + ω

[0034] where y ∈ C M is the received ultrasonic signal, ω ∈ C M is the waveform interference, and its variance matrix is λI -1 , λ > 0 is the noise precision coefficient, the matrix Φ ∈ C M×L is an overcomplete dictionary matrix, its number of columns is greater than the number of rows L > M, and α ∈ C L is the transmitted ultrasonic signal. Considering its sparsity, that is, it only has a small number of non-zero elements and the positions of the non-zero elements are unknown.

[0035] In order to recover the transmitted signal, anti-interference processing is performed on the ultrasonic wave, and a sensing matrix A ∈ C M×N, the observed value y of the received ultrasonic signal belongs to C M has sparsity and the sparsity degree is K.

[0036] The single-chip microcomputer main control circuit uses an intelligent algorithm for waveform processing. The specific process is as follows:

[0037] (1) Initialization: The iteration number t = 1; the residual r 0 = y; the initial value of the signal sparse representation coefficient support set Λ 0 = φ; the matching matrix A 0 = φ;

[0038] (2) Identification: u = {u j |u j = |<r i-1 , a j >|, 1 ≤ j ≤ N}, let J 0 = SUPP(u 2K )

[0039] (3) Update of the atomic candidate set: Let C t = Λ t-1 J 0 , A r = A t-1 a j , j ∈ J 0 ;

[0040] (4) Update of the estimated value of the coefficient of the transmitted ultrasonic signal in the signal sparse representation:

[0041] (5) Update the support set: Let Use the K columns corresponding in A r to represent with A tk ; Use the index number corresponding to A tk to represent with Λ tk , update the set Λ t = Λ tk ;

[0042] (6) Residual update:

[0043] (7) Update the iteration number and check whether the iteration stops: t = t + 1. If t ≤ K, then return to step (2); if t > K or the residual r t = 0, then the iteration stops and enters step (8);

[0044] (8) Estimate The set Λ t stores the positions of non-zero terms, and the corresponding non-zero values in are the finally iteratively obtained

[0045] The liquid level is measured by utilizing the propagation characteristics of ultrasonic waves in a liquid. Specifically, the terminal device includes an ultrasonic transmitter and a receiver, and both are in direct contact with the liquid to be measured through a specially designed liquid-medium coupling device. During operation, the ultrasonic transmitter emits a series of short-pulse ultrasonic waves into the liquid. These waves propagate inside the liquid to the liquid surface and then reflect back, and are received by the receiver. By accurately measuring the round-trip time of the ultrasonic waves and combining the known sound speed and the geometric parameters of the coupling device, the absolute height of the liquid surface can be calculated, improving the accuracy and stability of ultrasonic measurement.

[0046] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. The ground level monitoring terminal based on liquid medium ultrasonic wave is characterized by: It consists of an ultrasonic transmitter, a receiver, a liquid-medium coupling device, a control unit and an external bracket. The ultrasonic transmitter is responsible for emitting short pulse ultrasonic waves into the liquid. The receiver is used to receive ultrasonic signals reflected from the liquid surface. The liquid-medium coupling device can ensure contact and coupling between the ultrasonic transmitter and the receiver and the liquid to be tested. The control signal includes a signal processing module and a calculation module. The external bracket is used to protect the components inside the terminal device.

2. The ground liquid level monitoring terminal based on liquid-medium ultrasonic wave according to claim 1 is characterized in that: The signal processing module is responsible for processing the ultrasonic signal received by the receiver and extracting the round-trip time.

3. The ground liquid level monitoring terminal based on liquid-medium ultrasonic wave according to claim 2 is characterized in that: The calculation module calculates the absolute height of the liquid surface according to the known sound speed and the geometric parameters of the liquid-medium coupling device.

4. The ground liquid level monitoring terminal based on liquid-medium ultrasonic wave according to claim 1 is characterized in that: The liquid-medium coupling device is also provided with an ultrasonic sensor, and the ultrasonic sensor terminal is docked into two docking ports at the upper end of the liquid-medium coupling device, so that the ultrasonic radiation surface is placed on the upper surface of the bottom of the liquid-medium coupling device to ensure contact and coupling between the ultrasonic transmitter and receiver and the liquid to be tested.

5. The ground liquid level monitoring terminal based on liquid-medium ultrasonic wave according to claim 4 is characterized in that: The main modules integrated inside the ultrasonic sensor include ultrasonic transmitting and receiving circuits, single-chip microcomputer main control circuits, and temperature compensation circuits.

6. The ground liquid level monitoring terminal based on liquid-medium ultrasonic wave according to claim 5 is characterized in that: The single-chip microcomputer main control circuit utilizes an intelligent algorithm for waveform processing. The intelligent algorithm takes signal sparsity into consideration and adopts a variational mean field algorithm under a sparse state.

7. The ground liquid level monitoring terminal based on liquid-medium ultrasonic wave according to claim 6 is characterized in that: In order to recover the transmitted signal, the ultrasonic wave is processed for anti-interference and the sensor matrix A∈C is set. M×N , the received ultrasonic signal observation value y∈C M , which is sparse and has sparsity K.

8. The ground liquid level monitoring terminal based on liquid-medium ultrasonic wave according to claim 1 is characterized in that: The specific process of the single chip microcomputer main control circuit using intelligent algorithm waveform processing is as follows: (1) Initialization; (2) Identification; (3) Atomic candidate set update; (4) updating of the estimated value of the ultrasonic signal coefficient transmitted by the signal sparse representation; (5) Update the support set; (6) Residual update; (7) Update the number of iterations and check whether the iteration stops; (8) Estimation Set Λ t The non-zero positions are stored in The corresponding non-zero value in is obtained by the final iteration

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