Ultrasonic gas-liquid interface detection system and method based on frequency tracking

Abstract

The invention provides an ultrasonic gas-liquid interface detection system and method based on frequency tracking, and relates to the technical field of gas-liquid interface detection.The system comprises an ultrasonic transducer, and a probe of the ultrasonic transducer is arranged on a to-be-detected gas-liquid interface; the signal generation module is electrically connected with the ultrasonic transducer; the motor driving module is electrically connected with the motor, and the ultrasonic transducer is fixed on an output shaft of the motor; the signal acquisition module is electrically connected with the ultrasonic transducer and is used for acquiring working current and working voltage of the ultrasonic transducer; a frequency tracking module; a control system module; the signal generation module, the motor driving module, the signal acquisition module and the frequency tracking module are electrically connected with the control system module. The control system module performs phase difference detection according to the working current and the working voltage acquired by the signal acquisition module, and controls whether the resonant frequency emitted by the frequency tracking module is changed or not to judge whether the probe reaches the gas-liquid interface to be detected, so that the liquid level can be efficiently and sensitively detected.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid level detection, and in particular to an ultrasonic gas-liquid interface detection system and method based on frequency tracking. Background Art

[0002] With the development of science and technology, in the process of industrial production and medical diagnosis, the height, position and gas-liquid interface of the liquid can be detected to facilitate operations such as liquid stirring.

[0003] Traditional liquid detection methods, such as mechanical (when the gas-liquid interface is reached, the mechanical structure is triggered to achieve triggering) or optical (a laser sensor is set up, and when the gas-liquid interface is reached, the light is not received due to reflection or refraction, achieving triggering), etc., often have problems such as low accuracy, slow response speed, and susceptibility to interference, and it is difficult to meet the needs of actual applications.

[0004] In recent years, with the continuous development of ultrasonic technology, its application in the field of liquid detection has become increasingly widespread. The principle of ultrasonic gas-liquid detection is: ultrasonic waves are emitted to the liquid surface, and then the liquid surface is confirmed by receiving the reflected signal. However, the existing ultrasonic detection methods often have problems such as misjudgment and missed detection when detecting the gas-liquid interface, especially in the contact liquid level detection of small containers, which is difficult to meet the needs of practical applications. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the existing technology cannot accurately detect the gas-liquid interface. In order to overcome the defects of the above existing technology, the present invention provides an ultrasonic gas-liquid interface detection system and method based on frequency tracking.

[0006] The present invention provides an ultrasonic gas-liquid interface detection system based on frequency tracking, comprising:

[0007] An ultrasonic transducer, wherein a probe of the ultrasonic transducer is placed on the gas-liquid interface to be measured;

[0008] A signal generating module, wherein the signal generating module is electrically connected to the ultrasonic transducer;

[0009] A motor drive module, wherein the motor drive module is electrically connected to the motor, and the ultrasonic transducer is fixed on an output shaft of the motor;

[0010] A signal acquisition module, the signal acquisition module is electrically connected to the ultrasonic transducer and is used to collect the working current and working voltage of the ultrasonic transducer in real time;

[0011] Frequency tracking module, used to adjust the resonant frequency signal output;

[0012] The control system module, the signal generating module, the motor driving module, the signal acquisition module and the frequency tracking module are all electrically connected to the control system module; the control system module performs phase difference detection according to the working current and the working voltage collected by the signal acquisition module, and controls whether the resonant frequency emitted by the frequency tracking module changes, and the control system module determines whether the probe reaches the gas-liquid interface to be measured according to whether the resonant frequency changes.

[0013] Compared with the prior art, the ultrasonic gas-liquid interface detection system based on frequency tracking in the present application has the following advantages: whether the gas-liquid interface to be measured is reached is preliminarily judged by the changes in the working current and working voltage of the ultrasonic transducer, and whether the resonant frequency emitted by the frequency tracking module changes is controlled by whether the phase difference is zero, and the control system module further confirms that the probe reaches the gas-liquid interface to be measured according to whether the resonant frequency changes. It has made great improvements in accuracy, efficiency and environmental stability compared with traditional liquid level detection methods, and can efficiently and sensitively detect the position of the reagent gas-liquid interface and make indications, and has broad application prospects.

[0014] In a possible implementation, the signal generating module includes a driving chip U6 and a transformer T1;

[0015] The output control high end of the driving chip U6 is electrically connected to the gate of the MOS transistor Q1 through the resistor R10, the source of the MOS transistor Q1 is electrically connected to the gate of the MOS transistor Q1 through the resistor R11, the source of the MOS transistor Q1 is grounded, and the drain of the MOS transistor Q1 is electrically connected to one end of the primary side of the transformer T1;

[0016] The output control low end of the driving chip U6 is electrically connected to the gate of the MOS transistor Q2 through the resistor R12, the source of the MOS transistor Q2 is electrically connected to the gate of the MOS transistor Q2 through the resistor R14, the source of the MOS transistor Q2 is grounded, and the drain of the MOS transistor Q2 is electrically connected to the other end of the primary side of the transformer T1;

[0017] One end of the secondary side of the transformer T1 is electrically connected to one end of the ultrasonic transducer through the inductor L3, the other end of the secondary side of the transformer T1 is electrically connected to the other end of the ultrasonic transducer, and a capacitor C18 is connected in parallel across both ends of the ultrasonic transducer.

[0018] Compared with the prior art, the ultrasonic transducer is driven by the driving chip U6 in combination with the peripheral configuration circuit, and the power required by the ultrasonic transducer is conveniently adjusted by setting the transformer T1.

[0019] In a possible implementation, the signal acquisition module includes a current collector for collecting the working current of the ultrasonic transducer, and the current collector is connected in series between the secondary side of the transformer T1 and the ultrasonic transducer.

[0020] Compared with the prior art, the working current of the ultrasonic transducer can be conveniently detected by setting a current collector.

[0021] In a possible implementation, the signal acquisition module includes a voltage collector for collecting the working voltage of the ultrasonic transducer, and the voltage collector includes a resistor R74, a resistor R75 and a resistor R55, and the resistors R74, R75 and R55 are sequentially connected in series to form a series circuit, one end of the series circuit is electrically connected to one end of the secondary side of the transformer T1, and the other end of the series circuit is grounded, and the connection end of the resistor R75 and the resistor R55 outputs the working voltage of the ultrasonic transducer.

[0022] Compared with the prior art, the actual working voltage of the ultrasonic transducer is calculated and measured by combining the voltage division principle of the resistor with the resistance value, which is simple and convenient.

[0023] In a possible implementation, the frequency tracking module includes a voltage amplification zero-crossing detection circuit, a current amplification zero-crossing detection circuit and an XOR gate circuit, the input end of the voltage amplification zero-crossing detection circuit is electrically connected to the output end of the voltage collector, the output end of the voltage amplification zero-crossing detection circuit is electrically connected to one end of the XOR gate, the input end of the current amplification zero-crossing detection circuit is electrically connected to the output end of the current collector, the output end of the current amplification zero-crossing detection circuit is electrically connected to the other end of the XOR gate, and the output end of the XOR gate is electrically connected to the control system module.

[0024] Compared with the existing technology, the frequency tracking module can conveniently receive the phase difference change to adjust the resonant frequency and perform signal feedback.

[0025] In a possible implementation, the voltage amplification zero-crossing detection circuit includes an amplifier U1.1 and an amplifier U1.2;

[0026] The output end of the voltage collector is electrically connected to the negative input end of the amplifier U1.1 through a series resistor R17 and a capacitor C5, the negative input end of the amplifier U1.1 is electrically connected to the output end of the amplifier U1.1 through a resistor R18, the positive input end of the amplifier U1.1 is electrically connected to the power supply through a resistor R26, the positive input end of the amplifier U1.1 is grounded through a capacitor C16, and the output end of the amplifier U1.1 is electrically connected to the negative input end of the amplifier U1.2 through a series capacitor C3 and a resistor R22;

[0027] The negative input terminal of the amplifier U1.2 is electrically connected to the output terminal of the amplifier U1.2 through a resistor R23, the positive input terminal of the amplifier U1.2 is electrically connected to the power supply through a resistor R21, the positive input terminal of the amplifier U1.2 is grounded through a capacitor C17, and the output terminal of the amplifier U1.2 is electrically connected to one end of the XOR gate.

[0028] In a possible implementation, the control system module is also electrically connected to a display module for displaying the probe position, operating current, operating voltage and resonant frequency.

[0029] Compared with the prior art, by setting up a display module, it is convenient to observe data and adjust corresponding parameters.

[0030] Another technical solution of the present invention is to provide an ultrasonic gas-liquid interface detection method based on frequency tracking, wherein an ultrasonic transducer is fixed to the output end of the motor in advance, and a probe on the ultrasonic transducer is placed on the gas-liquid interface to be detected, comprising the following steps:

[0031] S1, the control system module sends a start command to the signal generating module, and the signal generating module drives the probe on the ultrasonic transducer to emit an ultrasonic signal with a variable frequency;

[0032] S2, the control system module sends a start command to the motor drive module, and the motor drive module drives the motor to drive the ultrasonic transducer to approach or move away from the gas-liquid interface to be measured;

[0033] S3, the signal acquisition module collects the working voltage and working current of the ultrasonic transducer in real time, and transmits them to the control system module, and the control system module performs phase difference detection according to the working voltage and working current;

[0034] S4, the control system module determines whether the phase difference is zero;

[0035] If so, the probe has not reached the gas-liquid interface to be measured, and the process returns to step S2; otherwise, the resonant frequency emitted by the frequency tracking module makes the phase difference zero, and the control system module sends a stop command to the signal generating module and the motor driving module according to the change in the resonant frequency, and the probe reaches the gas-liquid interface to be measured.

[0036] Compared with the prior art, the ultrasonic gas-liquid interface detection method based on frequency tracking in the present application has the following advantages: when the probe of the ultrasonic transducer is always in the gas at the beginning, the phase difference between the working voltage and the working current of the ultrasonic transducer is zero. If the ultrasonic transducer is continued to be driven by the motor until the probe just touches the liquid, the phase difference between the working voltage and the working current of the ultrasonic transducer is not zero at this time, and the frequency tracking module emits a resonant frequency to make the phase difference zero again. At this time, the resonant frequency suddenly changes. After the control system module detects the sudden change in the resonant frequency, it can be determined that the probe has reached the gas-liquid interface to be measured. It has been greatly improved in accuracy, efficiency, and environmental stability compared with the traditional liquid level detection method, and can efficiently and sensitively detect the position of the reagent gas-liquid interface and make an indication, and has broad application prospects.

[0037] In a possible implementation manner, step S3 specifically includes the following steps:

[0038] S31, the signal acquisition module collects the working voltage and working current of the ultrasonic transducer in real time;

[0039] S32, the control system module determines whether the changes in the operating voltage and the operating current exceed the voltage and current thresholds;

[0040] If so, the control system module performs phase difference detection and enters step S4; otherwise, the control system module controls the motor drive module to adjust the position of the ultrasonic transducer and returns to step S31.

[0041] Compared with the prior art, by comparing the changes of the operating voltage and the operating current with the voltage and current thresholds, false alarms caused by small floating changes are avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the overall system of an ultrasonic gas-liquid interface detection system based on frequency tracking of the present invention;

[0043] Figure 2 It is a schematic diagram of the module working process of an ultrasonic gas-liquid interface detection system based on frequency tracking of the present invention;

[0044] Figure 3 This is a power supply circuit diagram of an ultrasonic gas-liquid interface detection system based on frequency tracking of the present invention;

[0045] Figure 4 This is a circuit diagram of a signal generation module in an ultrasonic gas-liquid interface detection system based on frequency tracking of the present invention;

[0046] Figure 5 This is a circuit diagram of a frequency tracking module in an ultrasonic gas-liquid interface detection system based on frequency tracking of the present invention. DETAILED DESCRIPTION

[0047] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0048] In the description of the embodiments of the present application, 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 directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0049] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0050] The present application is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] Embodiment 1

[0052] See also Figures 1 to 5 As shown, this embodiment relates to the present invention to provide an ultrasonic gas-liquid interface detection system based on frequency tracking, comprising:

[0053] Ultrasonic transducer, the probe of the ultrasonic transducer is placed on the gas-liquid interface to be measured; the ultrasonic transducer can convert electrical energy into ultrasonic signals and send them out through the probe. At the same time, the working current and working voltage of the ultrasonic transducer are different depending on the environment in which the probe is located;

[0054] A signal generating module, the signal generating module is electrically connected to the ultrasonic transducer; the signal generating module is used to generate a driving signal for driving the ultrasonic transducer;

[0055] The motor drive module is electrically connected to the motor, and the ultrasonic transducer is fixed on the output shaft of the motor; the motor is driven by the motor drive module, and then the motor drives the ultrasonic transducer to approach or move away from the gas-liquid interface to be measured;

[0056] A signal acquisition module, the signal acquisition module is electrically connected to the ultrasonic transducer, and the signal acquisition module is used to collect the working current and working voltage of the ultrasonic transducer in real time;

[0057] Frequency tracking module, used to adjust the resonant frequency signal output;

[0058] The control system module, the signal generation module, the motor drive module, the signal acquisition module and the frequency tracking module are all electrically connected to the control system module.

[0059] The control system module performs phase difference detection based on the working current and working voltage collected by the signal acquisition module, and controls whether the resonant frequency emitted by the frequency tracking module changes. The control system module determines whether the probe reaches the gas-liquid interface to be measured based on whether the resonant frequency changes.

[0060] This embodiment preliminarily determines whether the gas-liquid interface to be measured is reached through changes in the working current and working voltage of the ultrasonic transducer, and then controls whether the resonant frequency emitted by the frequency tracking module changes by determining whether the phase difference is zero. The control system module further confirms that the probe has reached the gas-liquid interface to be measured based on whether the resonant frequency has changed. This method has made significant improvements in accuracy, efficiency, and environmental stability over traditional liquid level detection methods, and can efficiently and sensitively detect the position of the reagent gas-liquid interface and give indications, and has broad application prospects.

[0061] Among them, the signal generation module includes a driver chip U6 and a transformer T1;

[0062] The output control high end of the driving chip U6 is electrically connected to the gate of the MOS tube Q1 through the resistor R10, the source of the MOS tube Q1 is electrically connected to the gate of the MOS tube Q1 through the resistor R11, the source of the MOS tube Q1 is grounded, and the drain of the MOS tube Q1 is electrically connected to one end of the primary side of the transformer T1;

[0063] The output control low end of the driving chip U6 is electrically connected to the gate of the MOS tube Q2 through the resistor R12, the source of the MOS tube Q2 is electrically connected to the gate of the MOS tube Q2 through the resistor R14, the source of the MOS tube Q2 is grounded, and the drain of the MOS tube Q2 is electrically connected to the other end of the primary side of the transformer T1;

[0064] One end of the secondary side of the transformer T1 is electrically connected to one end of the ultrasonic transducer through the inductor L3, the other end of the secondary side of the transformer T1 is electrically connected to the other end of the ultrasonic transducer, and a capacitor C18 is connected in parallel to both ends of the ultrasonic transducer.

[0065] The ultrasonic transducer is driven by the driver chip U6 in combination with the peripheral configuration circuit, and the power required by the ultrasonic transducer is conveniently adjusted by setting the transformer T1.

[0066] The signal acquisition module includes a current collector for collecting the working current of the ultrasonic transducer, and the current collector is connected in series between the secondary side of the transformer T1 and the ultrasonic transducer, so as to facilitate the detection of the working current of the ultrasonic circulator.

[0067] The working current of the ultrasonic transducer can be conveniently detected by setting a current collector.

[0068] Among them, the signal acquisition module includes a voltage collector for collecting the working voltage of the ultrasonic transducer, and the voltage collector includes a resistor R74, a resistor R75 and a resistor R55. The resistors R74, R75 and R55 are connected in series in sequence to form a series circuit. One end of the series circuit is electrically connected to one end of the secondary side of the transformer T1, and the other end of the series circuit is grounded. The connection end of the resistor R75 and the resistor R55 outputs the working voltage of the ultrasonic transducer.

[0069] The actual working voltage of the ultrasonic transducer can be calculated and measured by using the voltage division principle of the resistor in combination with the resistance value, which is simple and convenient.

[0070] The frequency tracking module includes a voltage amplifying zero-crossing detection circuit, a current amplifying zero-crossing detection circuit and an XOR gate circuit. The input end of the voltage amplifying zero-crossing detection circuit is electrically connected to the output end of the voltage collector, the output end of the voltage amplifying zero-crossing detection circuit is electrically connected to one end of the XOR gate, the input end of the current amplifying zero-crossing detection circuit is electrically connected to the output end of the current collector, the output end of the current amplifying zero-crossing detection circuit is electrically connected to the other end of the XOR gate, and the output end of the XOR gate is electrically connected to the control system module.

[0071] The frequency tracking module can be used to conveniently receive phase difference changes to adjust the resonant frequency and provide signal feedback.

[0072] Specifically, the voltage detection circuit includes an amplifier U1.1 and an amplifier U1.2;

[0073] The output end of the voltage collector is electrically connected to the negative input end of the amplifier U1.1 through a series resistor R17 and a capacitor C5, the negative input end of the amplifier U1.1 is electrically connected to the output end of the amplifier U1.1 through a resistor R18, the positive input end of the amplifier U1.1 is electrically connected to the power supply through a resistor R26, the positive input end of the amplifier U1.1 is grounded through a capacitor C16, and the output end of the amplifier U1.1 is electrically connected to the negative input end of the amplifier U1.2 through a series capacitor C3 and a resistor R22;

[0074] The negative input terminal of amplifier U1.2 is electrically connected to the output terminal of amplifier U1.2 through resistor R23, the positive input terminal of amplifier U1.2 is electrically connected to the power supply through resistor R21, the positive input terminal of amplifier U1.2 is grounded through capacitor C17, and the output terminal of amplifier U1.2 is electrically connected to one end of the XOR gate.

[0075] The current detection circuit is the same as the voltage amplification and filtering detection circuit, the difference is that one inputs the voltage value and the other inputs the current value.

[0076] In this embodiment, the control system module is also electrically connected to a display module for displaying the probe position, operating current, operating voltage and resonant frequency.

[0077] The display module is mainly used to display the position of the probe, the working voltage, the changes in the working current signal and the changes in the resonant frequency, which is convenient for observing data and allows the user to set parameters and perform operation control.

[0078] This system can be applied to liquid analysis, liquid detection, liquid measurement and other scenarios where the gas-liquid interface needs to be determined, and can be used to achieve accurate gas-liquid interface detection and control.

[0079] Among them, see Figure 1 As shown, the signal generation module, motor drive module, display module, signal acquisition module and frequency tracking module are all electrically connected to the control system module, so the dotted box indicates the connection between the control system module and each module, while the non-control system module includes these modules. For specific connection methods, see Figure 2 shown.

[0080] Embodiment 2

[0081] This embodiment relates to an ultrasonic gas-liquid interface detection method based on frequency tracking, wherein an ultrasonic transducer is fixed to the output end of a motor in advance, and a probe on the ultrasonic transducer is placed on the gas-liquid interface to be detected, and the method comprises the following steps:

[0082] S1, the control system module sends a start command to the signal generating module, and the signal generating module drives the probe on the ultrasonic transducer to emit an ultrasonic signal with a variable frequency;

[0083] S2, the control system module sends a start command to the motor drive module, and the motor drive module drives the motor to drive the ultrasonic transducer to approach or move away from the gas-liquid interface to be measured;

[0084] S3, the signal acquisition module collects the working voltage and working current of the ultrasonic transducer in real time, and transmits them to the control system module, and the control system module performs phase difference detection according to the working voltage and working current;

[0085] S4, the control system module determines whether the phase difference is zero;

[0086] If so, the probe has not reached the gas-liquid interface to be measured, and the process returns to step S2; otherwise, the resonant frequency emitted by the frequency tracking module makes the phase difference zero, and the control system module sends a stop command to the signal generating module and the motor driving module according to the change in the resonant frequency, and the probe reaches the gas-liquid interface to be measured.

[0087] When the ultrasonic transducer probe is in the gas at the beginning, the phase difference between the working voltage and the working current of the ultrasonic transducer is zero. If the ultrasonic transducer is driven by the motor until the probe just touches the liquid, the phase difference between the working voltage and the working current of the ultrasonic transducer will not be zero. The frequency tracking module emits a resonant frequency to make the phase difference zero again. At this time, the resonant frequency suddenly changes. After the control system module detects the sudden change in the resonant frequency, it can be determined that the probe has reached the gas-liquid interface to be tested. It has made great improvements in accuracy, efficiency, and environmental stability compared to traditional liquid level detection methods. It can efficiently and sensitively detect the position of the reagent gas-liquid interface and make an indication, and has broad application prospects.

[0088] Wherein, in step S3, the following steps are specifically included:

[0089] S31, the signal acquisition module collects the working voltage and working current of the ultrasonic transducer in real time;

[0090] S32, the control system module determines whether the changes in the operating voltage and the operating current exceed the voltage and current thresholds;

[0091] If so, the control system module performs phase difference detection and enters step S4; otherwise, the control system module controls the motor drive module to adjust the position of the ultrasonic transducer and returns to step S31.

[0092] By comparing the changes in the operating voltage and current with the voltage and current thresholds, false alarms caused by small floating changes can be avoided.

[0093] Working principle:

[0094] When the probe is in the gas, the control system module controls the motor drive module to work, and the motor drive module drives the ultrasonic transducer to approach the gas-liquid interface to be measured through the motor; at this time, the signal generating module generates a driving signal of a certain frequency, driving the probe on the ultrasonic transducer to emit ultrasonic waves with variable frequency. When it does not contact the gas-liquid interface to be measured, the working voltage and working current of the ultrasonic transducer change very little, do not exceed the voltage and current thresholds, and the phase difference between the working voltage and the working current is zero.

[0095] When the probe just touches the liquid surface, the medium that the probe touches changes, the working voltage and working current of the ultrasonic transducer also change suddenly, and the phase difference between the working voltage and the working current also changes from zero to other values; after the signal acquisition module collects the working voltage and the working current, at this time, the control system module detects that the phase difference has changed significantly, and the control system module controls the resonant frequency emitted by the frequency tracking module to change, forcing the phase difference between the working voltage and the working current to return to zero; then, the control system module can judge whether the probe has touched the gas-liquid interface to be measured by whether the resonant frequency signal fed back by the frequency tracking module has changed, and perform corresponding shutdown processing on the signal generation module and the motor drive module.

[0096] During the whole process, the display module can display the working voltage and working current collected by the signal acquisition module and the resonant frequency data emitted by the frequency tracking module in real time, and allow users to set parameters and control operations.

[0097] This embodiment can accurately and quickly detect the gas-liquid interface, provide an effective liquid detection method in the fields of industrial medicine, and has broad application prospects in contact liquid level detection of small containers.

[0098] For example, it is used to detect the position of the liquid interface in the reagent tube in the biochemical analysis experiment. After the gas-liquid interface is detected, the ultrasonic power emitted by the ultrasonic transducer can be changed to allow the probe to continue to penetrate into the liquid to a fixed distance, and the solution in the reagent is mixed by ultrasound.

[0099] Alternatively, after the gas-liquid interface is detected, the pipette is controlled to extend downward to a corresponding depth in the liquid to extract the liquid in the reagent.

[0100] In the description of the embodiments of the present application, it should be noted that in the description of the present application, terms such as "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description, and does not indicate or imply that the device or component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present application.

[0101] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" etc. means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0102] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. An ultrasonic gas-liquid interface detection system based on frequency tracking, characterized in that: include: An ultrasonic transducer, wherein a probe of the ultrasonic transducer is placed on the gas-liquid interface to be measured; A signal generating module, wherein the signal generating module is electrically connected to the ultrasonic transducer; A motor drive module, wherein the motor drive module is electrically connected to the motor, and the ultrasonic transducer is fixed on an output shaft of the motor; A signal acquisition module, the signal acquisition module is electrically connected to the ultrasonic transducer and is used to collect the working current and working voltage of the ultrasonic transducer in real time; Frequency tracking module, used to adjust the resonant frequency signal output; The control system module, the signal generating module, the motor driving module, the signal acquisition module and the frequency tracking module are all electrically connected to the control system module; the control system module performs phase difference detection according to the working current and the working voltage collected by the signal acquisition module, and controls whether the resonant frequency emitted by the frequency tracking module changes, and the control system module determines whether the probe reaches the gas-liquid interface to be measured according to whether the resonant frequency changes.

2. The ultrasonic gas-liquid interface detection system based on frequency tracking according to claim 1, characterized in that: The signal generating module includes a driving chip U6 and a transformer T1; The output control high end of the driving chip U6 is electrically connected to the gate of the MOS transistor Q1 through the resistor R10, the source of the MOS transistor Q1 is electrically connected to the gate of the MOS transistor Q1 through the resistor R11, the source of the MOS transistor Q1 is grounded, and the drain of the MOS transistor Q1 is electrically connected to one end of the primary side of the transformer T1; The output control low end of the driving chip U6 is electrically connected to the gate of the MOS transistor Q2 through the resistor R12, the source of the MOS transistor Q2 is electrically connected to the gate of the MOS transistor Q2 through the resistor R14, the source of the MOS transistor Q2 is grounded, and the drain of the MOS transistor Q2 is electrically connected to the other end of the primary side of the transformer T1; One end of the secondary side of the transformer T1 is electrically connected to one end of the ultrasonic transducer through the inductor L3, the other end of the secondary side of the transformer T1 is electrically connected to the other end of the ultrasonic transducer, and a capacitor C18 is connected in parallel across both ends of the ultrasonic transducer.

3. The ultrasonic gas-liquid interface detection system based on frequency tracking according to claim 2, characterized in that: The signal acquisition module includes a current collector for collecting the working current of the ultrasonic transducer, and the current collector is connected in series between the secondary side of the transformer T1 and the ultrasonic transducer.

4. The ultrasonic gas-liquid interface detection system based on frequency tracking according to claim 2, characterized in that: The signal acquisition module includes a voltage collector for collecting the working voltage of the ultrasonic transducer, and the voltage collector includes a resistor R74, a resistor R75 and a resistor R55; The resistor R74, the resistor R75 and the resistor R55 are connected in series in sequence to form a series circuit, one end of the series circuit is electrically connected to one end of the secondary side of the transformer T1, the other end of the series circuit is grounded, and the connection end of the resistor R75 and the resistor R55 outputs the ultrasonic transducer working voltage.

5. The ultrasonic gas-liquid interface detection system based on frequency tracking according to claim 1, characterized in that: The frequency tracking module includes a voltage amplification zero-crossing detection circuit, a current amplification zero-crossing detection circuit and an XOR gate circuit; The input end of the voltage amplification zero-crossing detection circuit is electrically connected to the output end of the voltage collector, the output end of the voltage amplification zero-crossing detection circuit is electrically connected to one end of an XOR gate, the input end of the current amplification zero-crossing detection circuit is electrically connected to the output end of the current collector, the output end of the current amplification zero-crossing detection circuit is electrically connected to the other end of the XOR gate, and the output end of the XOR gate is electrically connected to a control system module.

6. The ultrasonic gas-liquid interface detection system based on frequency tracking according to claim 5, characterized in that: The voltage amplification zero-crossing detection circuit includes an amplifier U1.1 and an amplifier U1.2; The output end of the voltage collector is electrically connected to the negative input end of the amplifier U1.1 through a series resistor R17 and a capacitor C5, the negative input end of the amplifier U1.1 is electrically connected to the output end of the amplifier U1.1 through a resistor R18, the positive input end of the amplifier U1.1 is electrically connected to the power supply through a resistor R26, the positive input end of the amplifier U1.1 is grounded through a capacitor C16, and the output end of the amplifier U1.1 is electrically connected to the negative input end of the amplifier U1.2 through a series capacitor C3 and a resistor R22; The negative input terminal of the amplifier U1.2 is electrically connected to the output terminal of the amplifier U1.2 through a resistor R23, the positive input terminal of the amplifier U1.2 is electrically connected to the power supply through a resistor R21, the positive input terminal of the amplifier U1.2 is grounded through a capacitor C17, and the output terminal of the amplifier U1.2 is electrically connected to one end of the XOR gate.

7. The ultrasonic gas-liquid interface detection system based on frequency tracking according to claim 1, characterized in that: The control system module is also electrically connected to a display module for displaying the probe position, operating current, operating voltage and resonant frequency.

8. A method of an ultrasonic gas-liquid interface detection system based on frequency tracking according to any one of claims 1 to 7, characterized in that: The ultrasonic transducer is fixed to the output end of the motor in advance, and the probe on the ultrasonic transducer is placed on the gas-liquid interface to be measured, including the following steps: S1, the control system module sends a start command to the signal generating module, and the signal generating module drives the probe on the ultrasonic transducer to emit an ultrasonic signal with a variable frequency; S2, the control system module sends a start command to the motor drive module, and the motor drive module drives the motor to drive the ultrasonic transducer to approach or move away from the gas-liquid interface to be measured; S3, the signal acquisition module collects the working voltage and working current of the ultrasonic transducer in real time, and transmits them to the control system module, and the control system module performs phase difference detection according to the working voltage and working current; S4, the control system module determines whether the phase difference is zero; If so, the probe has not reached the gas-liquid interface to be measured, and the process returns to step S2; otherwise, the resonant frequency emitted by the frequency tracking module makes the phase difference zero, and the control system module sends a stop command to the signal generating module and the motor driving module according to the change in the resonant frequency, and the probe reaches the gas-liquid interface to be measured.

9. The method for ultrasonic gas-liquid interface detection based on frequency tracking according to claim 8, characterized in that: In step S3, the following steps are specifically included: S31, the signal acquisition module collects the working voltage and working current of the ultrasonic transducer in real time; S32, the control system module determines whether the changes in the operating voltage and the operating current exceed the voltage and current thresholds; If so, the control system module performs phase difference detection and enters step S4; otherwise, the control system module controls the motor drive module to adjust the position of the ultrasonic transducer and returns to step S31.

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