Waveguide tube type radar liquid level meter

Abstract

The invention discloses a waveguide tube type radar liquid level meter, and relates to the technical field of radar measurement, the waveguide tube type radar liquid level meter comprises a casing body, the top of the casing body is provided with a casing upper cover, the lower part of the casing body is coaxially provided with a flange plate, and the bottom end of the casing body is connected with a casing cavity penetrating through the inside of the flange plate; a lens is arranged in the machine shell cavity, and a conical horn is connected to the lower portion of the machine shell cavity. According to the waveguide tube type radar liquid level meter, a microwave emitter emits frequency-modulated waves, a waveguide tube guides the electromagnetic waves to be rebroadcast towards the surface of a medium, and the electromagnetic waves reflected by the surface of the medium are guided to a receiver along the same path; the receiver receives electromagnetic waves reflected by the surface of the measured medium, and the signal processor processes echo signals; based on the time-frequency relation between the transmitting signal and the receiving signal, the distance between the liquid level meter and the surface of the measured medium is determined and converted into the liquid level; according to the scheme, false echoes can be automatically restrained, and liquid level measurement is more accurate and more stable.

Description

Technical Field

[0001] The invention relates to the technical field of radar measurement, in particular to a waveguide type radar level meter. Background Art

[0002] Radar level meter is a universal radar level meter. It is a measuring instrument based on the time-travel principle. Radar waves run at the speed of light, and the running time can be converted into a level signal through electronic components. The probe emits a high-frequency pulse that propagates at the speed of light in space. When the pulse encounters the surface of the material, it is reflected back and received by the receiver in the instrument, which converts the distance signal into a level signal.

[0003] The radar level meters currently on the market can generally be divided into ordinary radar level meters and guided wave radar level meters; guided wave radar level meters are of two types: dry type and cable type; because the electromagnetic waves emitted by ordinary radar level meters are divergent, when the dielectric constant of the medium is small, the echo signal is too weak to make its measurement unstable, while the electromagnetic waves of guided wave radar level meters are propagated along the waveguide trunk or waveguide cable, the echo signal is stronger and the measurement is more stable; under normal circumstances, ordinary radar level meters measure a long distance, while guided wave radar level meters will not measure a long distance due to the stress on their waveguide trunks (cables) and other reasons; a waveguide tube radar level meter combines the advantages of ordinary radar level meters and guided wave radar level meters, and can overcome their shortcomings. Summary of the invention

[0004] In view of the shortcomings of the existing radar level meter technology, the present invention provides a 120GHz waveguide-based radar level meter, which combines radar technology with waveguide design to achieve high-reliability and high-stability liquid level measurement.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A waveguide radar level gauge comprises a casing body, a casing upper cover is installed on the top of the casing body, a flange is coaxially arranged below the casing body, and a casing cavity penetrating the inside of the flange is connected to the bottom end of the casing body;

[0006] A lens is arranged inside the housing cavity, a conical horn is connected below the housing cavity, and a waveguide is installed below the conical horn.

[0007] Optionally, the lens is made of PTFE.

[0008] Optionally, the lower end of the waveguide is directed toward the surface of the medium to be measured, and the waveguide is set as a circular guide tube with a frequency transmission condition of 120 GHz, and the waveguide is used to ensure directional emission and reception of microwave signals.

[0009] Optionally, a microwave transmitter, a microwave receiver, and a control and signal processor are also provided inside the casing body.

[0010] Optionally, the microwave transmitter is composed of a transmitting front-end circuit, a lens, and a conical horn, and is used to transmit a narrowband radio frequency signal, which is sent directionally to the surface of the medium to be measured through a waveguide.

[0011] Optionally, the microwave receiver is composed of a receiving front-end circuit, a lens, and a conical horn, and is used to receive the echo signal reflected from the surface of the medium under test, and use the receiving front-end circuit to perform orthogonal demodulation on the echo signal, and perform signal processing after filtering, intermediate frequency amplification and analog-to-digital conversion.

[0012] Optionally, the signal processor is used to perform time domain accumulation, spectrum analysis and refinement, constant false alarm detection processing, Kalman filtering, and target extraction on the received echo signal, determine the distance between the radar level meter and the medium surface and convert it into the liquid level.

[0013] Optionally, a Bluetooth communicator is also provided inside the casing body for wireless communication between the signal processor and a mobile phone APP, and the APP is used to display, set and modify the parameters of the liquid level meter.

[0014] The present invention provides a waveguide radar level meter, which has the following beneficial effects:

[0015] The waveguide radar level meter transmits a linear frequency modulated continuous wave into the waveguide through a transmitter, and the receiver receives the linear frequency modulated continuous wave reflected from the surface of the medium in real time; after orthogonal mixing of the transmitted linear frequency modulated wave and the received linear frequency modulated wave, a zero intermediate frequency signal is obtained through filtering, and the zero intermediate frequency frequency reflects the interface position between two materials with different dielectric constants; the echo is processed to make the liquid level measurement of the measured medium more accurate, and the false echo and interference caused by the environment are automatically suppressed;

[0016] in,

[0017] This level meter combines radar technology with waveguide design technology to achieve high-precision level measurement. It uses signal processing algorithms and anti-interference design to achieve stability and reliability of measurement results. It does not require direct contact with the measured liquid during measurement, thus avoiding contamination and corrosion of the radar level meter by chemical liquids. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the external structure of the liquid level meter in the invention;

[0019] Figure 2 It is a schematic diagram of measuring signal transmission in the invention;

[0020] Figure 3 It is a schematic diagram of the measurement process in the invention.

[0021] In the figure: 1. Casing cover; 2. Casing body; 3. Casing cavity; 4. Flange; 5. Lens; 6. Conical horn; 7. Waveguide. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0023] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] See also Figures 1 to 3 The present invention provides a technical solution: a waveguide radar level gauge, comprising a casing body 2, a casing upper cover 1 is installed on the top of the casing body 2, a flange 4 is coaxially arranged below the casing body 2, and a casing cavity 3 penetrating the inside of the flange 4 is connected to the bottom end of the casing body 2;

[0026] A lens 5 is provided inside the housing cavity 3. The lens 5 is made of PTFE. A conical horn 6 is connected to the bottom of the housing cavity 3. A waveguide 7 is installed below the conical horn 6. The lower end of the waveguide 7 faces the surface of the measured medium. The waveguide 7 is set as a circular guide tube with a frequency transmission condition of 120 GHz. The waveguide 7 is used to ensure the directional transmission of microwave signals.

[0027] The housing body 2 is also provided with a microwave transmitter, a microwave receiver, and a control and signal processor.

[0028] The microwave transmitter is composed of a transmitting front-end circuit, a lens 5, and a conical horn 6, and is used to transmit narrow-band radio frequency signals, which are sent to the surface of the measured medium in a direction through a waveguide 7.

[0029] The microwave receiver is composed of a receiving front-end circuit, a lens 5, and a conical horn 6, and is used to receive the echo signal reflected from the surface of the measured medium, and uses the receiving front-end circuit to perform orthogonal demodulation on the echo signal, and performs signal processing after filtering, intermediate frequency amplification and analog-to-digital conversion.

[0030] The signal processor is used to perform time domain accumulation, spectrum analysis and refinement, constant false alarm detection processing, Kalman filtering, and target extraction on the received echo signal, determine the distance between the radar level meter and the medium surface and convert it into the liquid level.

[0031] A Bluetooth communicator is also provided inside the housing body 2 for wireless communication between the signal processor and the mobile phone APP, and the APP is used to display, set and modify the parameters of the liquid level meter;

[0032] The liquid level meter adopts a combination of radar technology and waveguide 7 design technology to achieve high-precision liquid level measurement, and uses signal processing algorithms and anti-interference design to achieve stability and reliability of measurement results. In addition, there is no need to directly contact the measured liquid during measurement, avoiding contamination and corrosion of the radar level meter by chemical liquid.

[0033] The use method of the present invention: When the waveguide radar level meter is used, the working process is as follows:

[0034] like Figures 2 to 3 As shown, first, the microwave transmitter transmits a 120 GHz microwave signal, which is directed to the surface of the measured medium through the guidance of the waveguide 7; the design of the waveguide 7 ensures the directionality and stability of the microwave signal, wherein the microwave transmitter includes a phase-locked loop (PLL), a modulation signal generator, a voltage-controlled oscillator (VCO), a power divider, a power amplifier, a lens 5, and a conical horn 6, etc.;

[0035] Secondly, the microwave receiver receives the microwave signal reflected along the waveguide 7, and performs orthogonal demodulation, zero intermediate frequency amplification, A / D sampling, etc. on the echo signal, and sends the A / D sampling signal to the signal processor, which processes the zero intermediate frequency signal and extracts the liquid level information. The receiver includes a lens 5, a conical horn 6, a low noise amplifier (LNA), an orthogonal mixer, a filter, a zero intermediate frequency amplifier, etc.; the signal processing algorithm includes modules such as time domain accumulation, spectrum analysis, filter tracking, constant false alarm detection and distance estimation, and Bluetooth communication. The time domain accumulation module is mainly used to improve the signal-to-noise ratio, the spectrum analysis module is mainly used to analyze the impact of the environment on the echo signal spectrum, the filter tracking module is mainly used to resist interference and improve stability, the constant false alarm detection module calculates the detection curve to extract the target distance information, and the distance estimation module accurately determines the surface position of the medium and outputs the measurement result. At the same time, the liquid level meter can realize the Bluetooth communication between the signal processor and the mobile phone, and display, set, and modify the parameters of the radar liquid level meter through the mobile phone.

[0036] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A waveguide radar level meter, comprising a housing body (2), characterized in that: A casing upper cover (1) is installed on the top of the casing body (2), a flange (4) is coaxially arranged below the casing body (2), and a casing cavity (3) penetrating the interior of the flange (4) is connected to the bottom end of the casing body (2); A lens (5) is provided inside the housing cavity (3), a conical horn (6) is connected below the housing cavity (3), and a waveguide (7) is installed below the conical horn (6).

2. A waveguide radar level gauge according to claim 1, characterized in that: The lens (5) is made of PTFE material.

3. The waveguide radar level gauge according to claim 1, characterized in that: The lower end of the waveguide tube (7) faces the surface of the medium to be measured, and the waveguide tube (7) is set as a circular tube with a frequency transmission condition of 120 GHz. The waveguide tube (7) is used to ensure the directional emission and reception of microwave signals.

4. The waveguide radar level gauge according to claim 1, characterized in that: A microwave transmitter, a microwave receiver, and a control and signal processor are also arranged inside the casing body (2).

5. The waveguide radar level gauge according to claim 4, characterized in that: The microwave transmitter is composed of a transmitting front-end circuit, a lens (5), and a conical horn (6), and is used to transmit a narrowband radio frequency signal, which is sent directionally to the surface of the medium to be measured through a waveguide (7).

6. A waveguide radar level gauge according to claim 4, characterized in that: The microwave receiver is composed of a receiving front-end circuit, a lens (5) and a conical horn (6), and is used to receive an echo signal reflected from the surface of a measured medium, perform orthogonal demodulation on the echo signal using the receiving front-end circuit, and perform signal processing after filtering, intermediate frequency amplification and analog-to-digital conversion.

7. The waveguide radar level gauge according to claim 4, characterized in that: The signal processor is used to perform time domain accumulation, spectrum analysis and refinement, constant false alarm detection processing, Kalman filtering, and target extraction on the received echo signal, determine the distance between the radar level meter and the medium surface, and convert it into the liquid level.

8. The waveguide radar level gauge according to claim 4, characterized in that: Said A Bluetooth communicator is also provided inside the housing body (2) for wireless communication between the signal processor and the mobile phone APP. Use the APP to display, set and modify the level meter parameters.

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