Fire hydrant monitoring device, fire hydrant, fire hydrant cap rod and fire hydrant door cover

Abstract

The utility model provides a fire hydrant monitoring device, a fire hydrant, a fire hydrant cap rod and a fire hydrant door cover, and relates to the technical field of fire hydrants. The fire hydrant monitoring device comprises a control assembly, a piezoelectric sensor and a pressure sensor, wherein the piezoelectric sensor and the pressure sensor are electrically connected to the control assembly. The control assembly comprises a bias voltage circuit, a pressure acquisition circuit electrically connected to the pressure sensor, a first-stage signal amplification circuit electrically connected to the piezoelectric sensor and the bias voltage circuit, a second-stage signal amplification circuit electrically connected to the first-stage signal amplification circuit, and an automatic gain amplification circuit electrically connected to the second-stage signal amplification circuit. And the controller is electrically connected with the pressure acquisition circuit and the automatic gain amplification circuit. The pressure acquisition circuit utilizes a first operational amplifier to carry out signal processing through combination of resistors and capacitors so as to realize acquisition and amplification of pressure signals. According to the circuit design, the state of the fire hydrant and accurate monitoring of a water supply pipeline are ensured, and reliable technical support is provided for fire safety management.

Description

Technical Field

[0001] The utility model relates to the technical field of fire hydrants, and in particular, to a fire hydrant monitoring device, a fire hydrant, a fire hydrant cap rod and a fire hydrant door cover. Background Art

[0002] With the acceleration of the urbanization process, fire safety has become an important part of the public safety field. Traditional fire hydrant systems play a crucial role in emergencies such as fires, but they usually lack real-time monitoring and intelligent management functions. In recent years, with the development of Internet of Things (IoT) technology, intelligent fire hydrant systems have emerged, which can provide better monitoring and management functions to improve the efficiency and response speed of fire safety.

[0003] Existing intelligent fire hydrant systems generally include the following aspects: Status monitoring: Intelligent fire hydrants can monitor the usage status of fire hydrants in real time, including whether the fire hydrants are illegally used or damaged. Remote control: Through the remote control function, the fire department can remotely open or close the fire hydrants in case of emergencies. Data recording: Intelligent fire hydrants can record the usage history, including data such as usage time, frequency, and flow rate. Location function: The integrated GPS or network-based positioning system can quickly locate the position of the fire hydrants for quick response in case of emergencies.

[0004] Although existing intelligent fire hydrant systems have made some progress in monitoring the usage status of fire hydrants, they have obvious deficiencies in monitoring the leakage status of pipelines. Pipeline leakage not only causes waste of water resources, but may also damage urban infrastructure, increase maintenance costs, and affect the normal use of fire hydrants in case of fires.

[0005] In the prior art, there is a technology for monitoring water leakage in water supply pipelines through sound waves. However, there are some technical challenges in its practical application. Especially when monitoring water leakage through sound, due to the interference of pipeline materials, ambient noise, and the sound of water flow in the pipeline, the sound wave signals generated by water leakage are often weak. In order to improve the detection accuracy, these weak sound wave signals need to be amplified.

[0006] Existing audio signal amplification technologies often have distortion problems during the amplification process. Due to these distortion problems, the amplified audio signals are difficult to be accurately identified and analyzed, thus affecting the accuracy and reliability of water leakage monitoring. Therefore, developing an audio signal amplification technology that can reduce distortion and improve signal quality during the amplification process is of great significance for improving the efficiency and accuracy of pipeline water leakage monitoring.

[0007] In view of this, the applicant has specifically proposed this application after studying the existing technologies. Summary of the Utility Model

[0008] The present utility model provides a fire hydrant monitoring device, a fire hydrant, a fire hydrant cap rod and a fire hydrant door cover, aiming to improve at least one of the above technical problems.

[0009] To solve the above technical problems, the present utility model provides a fire hydrant monitoring device, which includes a piezoelectric sensor, a pressure sensor and a control component that can be engaged with a fire hydrant or a fire hydrant fitting. The signal output ends of the piezoelectric sensor and the pressure sensor are electrically connected to the signal receiving end of the control component.

[0010] The control component includes a bias voltage circuit, a pressure acquisition circuit electrically connected to the pressure sensor, a first-stage signal amplification circuit electrically connected to the piezoelectric sensor and the bias voltage circuit, a second-stage signal amplification circuit electrically connected to the first-stage signal amplification circuit, an automatic gain amplification circuit electrically connected to the second-stage signal amplification circuit, and a controller electrically connected to the pressure acquisition circuit and the automatic gain amplification circuit.

[0011] The pressure acquisition circuit includes a first operational amplifier. The non-inverting input terminal of the first operational amplifier is electrically connected to the pressure sensor through a first resistor. The non-inverting input terminal of the first operational amplifier is grounded through a first capacitor. The non-inverting input terminal of the first operational amplifier is electrically connected to the output terminal of the first operational amplifier through a second resistor and a second capacitor connected in series. The inverting input terminal of the first operational amplifier is electrically connected to the output terminal of the first operational amplifier. The negative power supply terminal of the first operational amplifier is grounded. The positive power supply terminal of the first operational amplifier is electrically connected to a power supply and grounded through a third capacitor. One end of the first resistor away from the first operational amplifier is grounded through a third resistor. The output terminal of the first operational amplifier is electrically connected to the controller.

[0012] In an optional embodiment, the first-stage signal amplification circuit includes a second operational amplifier. The second operational amplifier is used to amplify the signal.

[0013] The positive power supply terminal of the second operational amplifier is electrically connected to a power supply. The negative power supply terminal of the second operational amplifier is grounded. The non-inverting input terminal of the second operational amplifier is electrically connected to the output terminal of the bias voltage circuit and the first output terminal of the piezoelectric sensor. The inverting input terminal of the second operational amplifier is electrically connected to the second output terminal of the piezoelectric sensor through a fourth capacitor. The inverting input terminal of the second operational amplifier is electrically connected to the output terminal of the second operational amplifier through a fourth resistor and a fifth capacitor connected in parallel. The output terminal of the second operational amplifier is electrically connected to the positive electrode of a first electrolytic capacitor. The negative electrode of the first electrolytic capacitor is electrically connected to the first end of a sixth capacitor.

[0014] The first output terminal of the piezoelectric sensor is electrically connected to the second output terminal of the piezoelectric sensor through a third resistor.

[0015] In an optional embodiment, the secondary signal amplification circuit includes a third operational amplifier. The third operational amplifier is used to amplify signals.

[0016] The non-inverting input terminal of the third operational amplifier is electrically connected to the second end of the sixth capacitor. The non-inverting input terminal of the third operational amplifier is electrically connected to the output terminal of the bias voltage circuit through a fifth resistor. The inverting input terminal of the third operational amplifier is electrically connected to the output terminal of the bias voltage circuit through a sixth resistor. One end of the sixth resistor away from the third operational amplifier is grounded through a seventh capacitor. The inverting input terminal of the third operational amplifier is electrically connected to the output terminal of the third operational amplifier through a seventh resistor. The output terminal of the third operational amplifier is electrically connected to the output terminal of the bias voltage circuit through an eighth capacitor. The output terminal of the third operational amplifier outputs an audio signal SOUND through an eighth resistor.

[0017] In an optional embodiment, the automatic gain amplification circuit includes an audio amplification chip. The model of the audio amplification chip is Max9814.

[0018] The CT pin of the audio amplification chip is grounded through a ninth capacitor. The SHON pin of the audio amplification chip is electrically connected to the power supply. The CG pin of the audio amplification chip is grounded through a second electrolytic capacitor. The NC1 pin of the audio amplification chip is grounded. The VDD pin of the audio amplification chip is electrically connected to the power supply. The output pin OUT of the audio amplification chip outputs a gain amplified signal through a ninth resistor. One end of the ninth resistor away from the audio amplification chip is grounded through a tenth capacitor. The GND pin and PAD pin of the audio amplification chip are grounded.

[0019] The CIN pin of the audio amplification chip is electrically connected to the output terminal of the secondary signal amplification circuit through an eleventh capacitor. The A / R pin and GAIN pin of the audio amplification chip are not connected. The NC2 pin of the audio amplification chip is grounded. The BIAS pin of the audio amplification chip is grounded through a twelfth capacitor. The MIC BIAS pin of the audio amplification chip is electrically connected to the output terminal of the secondary signal amplification circuit through a tenth resistor. The MIC BIAS pin of the audio amplification chip is electrically connected to the first end of the eleventh resistor. The second end of the eleventh resistor is electrically connected to the first end of the twelfth resistor. The second end of the twelfth resistor is grounded. The TH pin of the audio amplification chip is electrically connected to the first end of the twelfth resistor.

[0020] In an alternative embodiment, the bias voltage circuit includes a fourth operational amplifier. The output terminal of the fourth operational amplifier is used to output the bias voltage.

[0021] The positive power supply terminal of the fourth operational amplifier is electrically connected to the power supply. The positive power supply terminal of the fourth operational amplifier is grounded through a thirteenth capacitor. The negative power supply terminal of the fourth operational amplifier is grounded. The non-inverting input terminal of the fourth operational amplifier is electrically connected to the power supply through a thirteenth resistor. The non-inverting input terminal of the fourth operational amplifier is grounded through a fourteenth resistor and a fourteenth capacitor connected in parallel. The inverting input terminal of the fourth operational amplifier is electrically connected to the output terminal of the fourth operational amplifier. The output terminal of the fourth operational amplifier is grounded through a fifteenth capacitor and a third electrolytic capacitor connected in parallel. Among them, the positive electrode of the third electrolytic capacitor is electrically connected to the output terminal of the fourth operational amplifier, and the negative electrode of the third electrolytic capacitor is grounded.

[0022] In an alternative embodiment, the data collected by the pressure sensor is accessed to the control component through 4-20mA.

[0023] In an alternative embodiment, the fire hydrant monitoring device further includes a communication module. The communication module is communicatively connected to the controller.

[0024] The present application further provides a fire hydrant, which includes the fire hydrant monitoring device described in any paragraph of the first aspect.

[0025] The present application further provides a fire hydrant cap rod, which includes the fire hydrant monitoring device described in any paragraph of the first aspect.

[0026] The present application further provides a fire hydrant door cover, which includes the fire hydrant monitoring device described in any paragraph of the first aspect.

[0027] By adopting the above technical solutions, the following technical effects can be achieved by the present utility model:

[0028] The fire hydrant monitoring device of the embodiment of the present utility model integrates a noise and pressure device, enabling the intelligent fire hydrant to monitor not only the pipeline leakage, but also the pipeline pressure and the status of the fire hydrant. And it is possible to integrate the fire hydrant monitoring device into the fire hydrant, thereby effectively reducing the repeated installation of noise and pressure devices in the pipeline per unit distance and saving the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present utility model, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 is the circuit diagram of the pressure acquisition circuit.

[0031] Figure 2 is the circuit diagram of the first-stage signal amplification circuit and the second-stage signal amplification circuit.

[0032] Figure 3 is the circuit diagram of the automatic gain amplification circuit.

[0033] Figure 4 is the circuit diagram of the controller circuit.

[0034] Figure 5 is the circuit diagram of the bias voltage circuit.

[0035] Markings in the figure: U8 - the first operational amplifier, U8A - the second operational amplifier, U8B - the third operational amplifier, U3 - the fourth operational amplifier, R38 - the first resistor, R34 - the second resistor, R41 - the third resistor, R16 - the fourth resistor, R14 - the fifth resistor, R18 - the sixth resistor, R17 - the seventh resistor, R28 - the ninth resistor, R26 - the tenth resistor, R25 - the eleventh resistor, R27 - the twelfth resistor, R21 - the thirteenth resistor, R24 - the fourteenth resistor, C37 - the first capacitor, C34 - the second capacitor, C35 - the third capacitor, C15 - the fourth capacitor, C16 - the fifth capacitor, C42 - the sixth capacitor, C17 - the seventh capacitor, C14 - the eighth capacitor, C21 - the ninth capacitor, C41 - the tenth capacitor, C40 - the eleventh capacitor, C39 - the twelfth capacitor, C18 - the thirteenth capacitor, C19 - the fourteenth capacitor, C22 - the fifteenth capacitor, C43 - the first electrolytic capacitor, C44 - the second electrolytic capacitor, C20 - the third electrolytic capacitor. Specific embodiments

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present utility model. Therefore, the following detailed description of the embodiments of the present utility model provided in the drawings is not intended to limit the scope of the present utility model to be protected, but merely represents the selected embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present utility model.

[0037] Example 1. Consisting of Figures 1 to 5 As shown in Figures 1 to 5 , an embodiment of the present utility model provides a fire hydrant monitoring device, which includes a piezoelectric sensor, a pressure sensor, and a control component that can be engaged with a fire hydrant or a fire hydrant fitting. The signal output ends of the piezoelectric sensor and the pressure sensor are electrically connected to the signal receiving end of the control component. Preferably, the data collected by the pressure sensor is accessed to the control component through 4 - 20mA.

[0038] The control component includes a bias voltage circuit, a pressure acquisition circuit electrically connected to the pressure sensor, a first - stage signal amplification circuit electrically connected to the piezoelectric sensor and the bias voltage circuit, a second - stage signal amplification circuit electrically connected to the first - stage signal amplification circuit, an automatic gain amplification circuit electrically connected to the second - stage signal amplification circuit, and a controller electrically connected to the pressure acquisition circuit and the automatic gain amplification circuit. Preferably, the fire hydrant monitoring device further includes a communication module. The communication module is communicatively connected to the controller. The controller is a single - chip microcomputer. The model of the single - chip microcomputer is STM32L051.

[0039] Specifically, through the communication module, the collected audio signal can be sent to the server for analysis, or after local analysis is completed, the analysis result can be uploaded to the server in a timely manner to monitor the fire hydrant and the fire hydrant pipeline in a timely manner, which has good practical significance. The fire hydrant monitoring device in the embodiment of the present utility model can effectively avoid the problem that the detected signal is distorted and cannot be recognized after amplification, and well guarantees the leak detection quality of the water supply network.

[0040] The pressure acquisition circuit includes a first operational amplifier U8. Preferably, the model of the first operational amplifier U8 is OPA347SA. The non - inverting input terminal of the first operational amplifier U8 is electrically connected to the pressure sensor through a first resistor R38. The non - inverting input terminal of the first operational amplifier U8 is grounded through a first capacitor C37. The non - inverting input terminal of the first operational amplifier U8 is electrically connected to the output terminal of the first operational amplifier U8 through a second resistor R34 and a second capacitor C34 connected in series. The inverting input terminal of the first operational amplifier U8 is electrically connected to the output terminal of the first operational amplifier U8. The negative power supply terminal of the first operational amplifier U8 is grounded. The positive power supply terminal of the first operational amplifier U8 is electrically connected to the power supply and grounded through a third capacitor C35. One end of the first resistor R38 far from the first operational amplifier U8 is grounded through a third resistor R41. The output terminal of the first operational amplifier U8 is electrically connected to the controller.

[0041] The fire hydrant monitoring device according to the embodiment of the present utility model integrates a noise and pressure device, enabling the intelligent fire hydrant to monitor pipeline leakage, pipeline pressure, and the status of the fire hydrant. Moreover, the fire hydrant monitoring device can be integrated into the fire hydrant, effectively reducing the repeated installation of noise and pressure devices in the pipeline per unit distance and saving construction costs.

[0042] As Figure 2 shown, based on the above embodiment, in an optional embodiment of the present utility model, the primary signal amplification circuit includes a second operational amplifier U8A. The second operational amplifier U8A is used to amplify the signal. Preferably, the model of the second operational amplifier U8A is LMC6482.

[0043] The positive power supply terminal of the second operational amplifier U8A is electrically connected to the power supply. The negative power supply terminal of the second operational amplifier U8A is grounded. The non-inverting input terminal of the second operational amplifier U8A is electrically connected to the output terminal of the bias voltage circuit and the first output terminal of the piezoelectric sensor. The inverting input terminal of the second operational amplifier U8A is electrically connected to the second output terminal of the piezoelectric sensor through a fourth capacitor C15. The inverting input terminal of the second operational amplifier U8A is electrically connected to the output terminal of the second operational amplifier U8A through a fourth resistor R16 and a fifth capacitor C16 connected in parallel. The output terminal of the second operational amplifier U8A is electrically connected to the positive electrode of a first electrolytic capacitor C43. The negative electrode of the first electrolytic capacitor C43 is electrically connected to the first end of a sixth capacitor C42.

[0044] The first output terminal of the piezoelectric sensor is electrically connected to the second output terminal of the piezoelectric sensor through a third resistor R41.

[0045] As Figure 2 shown, based on the above embodiment, in an optional embodiment of the present utility model, the secondary signal amplification circuit includes a third operational amplifier U8B. The third operational amplifier U8B is used to amplify the signal. Preferably, the model of the third operational amplifier U8B is LMC6482.

[0046] The non-inverting input terminal of the third operational amplifier U8B is electrically connected to the second terminal of the sixth capacitor C42. The non-inverting input terminal of the third operational amplifier U8B is electrically connected to the output terminal of the bias voltage circuit through the fifth resistor R14. The inverting input terminal of the third operational amplifier U8B is electrically connected to the output terminal of the bias voltage circuit through the sixth resistor R18. One end of the sixth resistor R18 far from the third operational amplifier U8B is grounded through the seventh capacitor C17. The inverting input terminal of the third operational amplifier U8B is electrically connected to the output terminal of the third operational amplifier U8B through the seventh resistor R17. The output terminal of the third operational amplifier U8B is electrically connected to the output terminal of the bias voltage circuit through the eighth capacitor C14. The output terminal of the third operational amplifier U8B outputs an audio signal SOUND through the eighth resistor.

[0047] As Figure 3 shown, on the basis of the above embodiment, in an optional embodiment of the present invention, the automatic gain amplification circuit includes an audio amplification chip. The model of the audio amplification chip is Max9814.

[0048] The CT pin of the audio amplification chip is grounded through the ninth capacitor C21. The SHON pin of the audio amplification chip is electrically connected to the power supply. The CG pin of the audio amplification chip is grounded through the second electrolytic capacitor C44. The NC1 pin of the audio amplification chip is grounded. The VDD pin of the audio amplification chip is electrically connected to the power supply. The output pin OUT of the audio amplification chip outputs a gain amplification signal through the ninth resistor R28. One end of the ninth resistor R28 far from the audio amplification chip is grounded through the tenth capacitor C41. The GND pin and the PAD pin of the audio amplification chip are grounded.

[0049] The CIN pin of the audio amplification chip is electrically connected to the output terminal of the secondary signal amplification circuit through the eleventh capacitor C40. The A / R pin and the GAIN pin of the audio amplification chip are not connected. The NC2 pin of the audio amplification chip is grounded. The BIAS pin of the audio amplification chip is grounded through the twelfth capacitor C39. The MICBIAS pin of the audio amplification chip is electrically connected to the output terminal of the secondary signal amplification circuit through the tenth resistor R26. The MIC BIAS pin of the audio amplification chip is electrically connected to the first end of the eleventh resistor R25. The second end of the eleventh resistor R25 is electrically connected to the first end of the twelfth resistor R27. The second end of the twelfth resistor R27 is grounded. The TH pin of the audio amplification chip is electrically connected to the first end of the twelfth resistor R27.

[0050] As Figure 5As shown, on the basis of the above embodiments, in an optional embodiment of the present utility model, the bias voltage circuit includes a fourth operational amplifier U3. The output terminal of the fourth operational amplifier U3 is used to output the bias voltage. Preferably, the model of the fourth operational amplifier U3 is LM321.

[0051] The positive power supply terminal of the fourth operational amplifier U3 is electrically connected to the power supply. The positive power supply terminal of the fourth operational amplifier U3 is grounded through a thirteenth capacitor C18. The negative power supply terminal of the fourth operational amplifier U3 is grounded. The non-inverting input terminal of the fourth operational amplifier U3 is electrically connected to the power supply through a thirteenth resistor R21. The non-inverting input terminal of the fourth operational amplifier U3 is grounded through a fourteenth resistor R24 and a fourteenth capacitor C19 connected in parallel. The inverting input terminal of the fourth operational amplifier U3 is electrically connected to the output terminal of the fourth operational amplifier U3. The output terminal of the fourth operational amplifier U3 is grounded through a fifteenth capacitor C22 and a third electrolytic capacitor C20 connected in parallel. Among them, the positive electrode of the third electrolytic capacitor C20 is electrically connected to the output terminal of the fourth operational amplifier U3, and the negative electrode of the third electrolytic capacitor C20 is grounded.

[0052] Specifically, when the existing pipeline leakage monitoring device amplifies signals, there is a probability of distortion and inability to identify. After the pipeline leakage signal collected by the fire hydrant monitoring device in the embodiment of the present utility model is amplified with bias, the automatic gain is used to judge the pipeline leakage by the single-chip microcomputer, which can solve the problem of amplified distortion of the pipeline leakage signal, and then ensure the acquisition and identification of the pipeline leakage situation in the full range and report it.

[0053] On the basis of the above embodiments, in an optional embodiment of the present utility model, the fire hydrant monitoring device further includes a battery. The battery is used to supply power to the control component. In other embodiments, the power supply can be powered by a power supply instead of using a battery.

[0054] Embodiment 2: The present application further provides a fire hydrant, which includes the fire hydrant monitoring device described in any section of Embodiment 1.

[0055] Embodiment 3: The present application further provides a fire hydrant cap rod, which includes the fire hydrant monitoring device described in any section of Embodiment 1. Preferably, the control component is integrated in the intelligent cap of the cap rod, and the piezoelectric sensor and the pressure sensor are integrated in the cap rod base, and the two are connected by a connecting wire;

[0056] Embodiment 4: The present application further provides a fire hydrant door cover, which includes the fire hydrant monitoring device described in any section of Embodiment 1. Preferably, the piezoelectric sensor, the pressure sensor and the control component are all integrated on the fire hydrant door cover.

[0057] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A fire hydrant monitoring device, characterized in that: It comprises a piezoelectric sensor, a pressure sensor and a control component that can be connected to a fire hydrant or a fire hydrant accessory; the signal output ends of the piezoelectric sensor and the pressure sensor are electrically connected to the signal receiving end of the control component; The control component includes a bias voltage circuit, a pressure acquisition circuit electrically connected to the pressure sensor, a primary signal amplification circuit electrically connected to the piezoelectric sensor and the bias voltage circuit, a secondary signal amplification circuit electrically connected to the primary signal amplification circuit, an automatic gain amplification circuit electrically connected to the secondary signal amplification circuit, and a controller electrically connected to the pressure acquisition circuit and the automatic gain amplification circuit; The pressure acquisition circuit comprises a first operational amplifier (U8); the non-inverting input terminal of the first operational amplifier (U8) is electrically connected to the pressure sensor through a first resistor (R38); the non-inverting input terminal of the first operational amplifier (U8) is grounded through a first capacitor (C37); the non-inverting input terminal of the first operational amplifier (U8) is electrically connected to the output terminal of the first operational amplifier (U8) through a second resistor (R34) and a second capacitor (C34) arranged in series; the inverting input terminal of the first operational amplifier (U8) is electrically connected to the output terminal of the first operational amplifier (U8); the negative power supply terminal of the first operational amplifier (U8) is grounded; the positive power supply terminal of the first operational amplifier (U8) is electrically connected to a power supply and is grounded through a third capacitor (C35); one end of the first resistor (R38) away from the first operational amplifier (U8) is grounded through a third resistor (R41); and the output terminal of the first operational amplifier (U8) is electrically connected to the controller.

2. A fire hydrant monitoring device according to claim 1, characterized in that , the first-stage signal amplification circuit includes a second operational amplifier (U8A); the second operational amplifier (U8A) is used to amplify the signal; The positive power supply terminal of the second operational amplifier (U8A) is electrically connected to the power supply; the negative power supply terminal of the second operational amplifier (U8A) is grounded; the non-inverting input terminal of the second operational amplifier (U8A) is electrically connected to the output terminal of the bias voltage circuit and the first output terminal of the piezoelectric sensor; the inverting input terminal of the second operational amplifier (U8A) is electrically connected to the second output terminal of the piezoelectric sensor through the fourth capacitor (C15); the inverting input terminal of the second operational amplifier (U8A) is electrically connected to the output terminal of the second operational amplifier (U8A) through the fourth resistor (R16) and the fifth capacitor (C16) arranged in parallel; the output terminal of the second operational amplifier (U8A) is electrically connected to the positive electrode of the first electrolytic capacitor (C43); the negative electrode of the first electrolytic capacitor (C43) is electrically connected to the first end of the sixth capacitor (C42); The first output end of the piezoelectric sensor is electrically connected to the second output end of the piezoelectric sensor through a third resistor (R41).

3. A fire hydrant monitoring device according to claim 2, characterized in that , the secondary signal amplification circuit includes a third operational amplifier (U8B); the third operational amplifier (U8B) is used to amplify the signal; The non-inverting input terminal of the third operational amplifier (U8B) is electrically connected to the second terminal of the sixth capacitor (C42); the non-inverting input terminal of the third operational amplifier (U8B) is electrically connected to the output terminal of the bias voltage circuit through a fifth resistor (R14); the inverting input terminal of the third operational amplifier (U8B) is electrically connected to the output terminal of the bias voltage circuit through a sixth resistor (R18); and one end of the sixth resistor (R18) away from the third operational amplifier (U8B) is grounded through a seventh capacitor (C17); The inverting input terminal of the third operational amplifier (U8B) is electrically connected to the output terminal of the third operational amplifier (U8B) through a seventh resistor (R17); The output end of the third operational amplifier (U8B) is electrically connected to the output end of the bias voltage circuit through an eighth capacitor (C14); The output end of the third operational amplifier (U8B) outputs the audio signal SOUND through the eighth resistor.

4. A fire hydrant monitoring device according to claim 1, characterized in that , the automatic gain amplifier circuit includes an audio amplifier chip; the model of the audio amplifier chip is Max9814; The CT pin of the audio amplifier chip is grounded through a ninth capacitor (C21); the SHON pin of the audio amplifier chip is electrically connected to a power supply; the CG pin of the audio amplifier chip is grounded through a second electrolytic capacitor (C44); the NC1 pin of the audio amplifier chip is grounded; the VDD pin of the audio amplifier chip is electrically connected to a power supply; the output pin OUT of the audio amplifier chip outputs a gain amplified signal through a ninth resistor (R28); the end of the ninth resistor (R28) away from the audio amplifier chip is grounded through a tenth capacitor (C41); the GND pin and the PAD pin of the audio amplifier chip are grounded; The CIN pin of the audio amplifier chip is electrically connected to the output end of the secondary signal amplifier circuit through an eleventh capacitor (C40); the A / R pin and the GAIN pin of the audio amplifier chip are not connected; the NC2 pin of the audio amplifier chip is grounded; the BIAS pin of the audio amplifier chip is grounded through a twelfth capacitor (C39); the MICBIAS pin of the audio amplifier chip is electrically connected to the output end of the secondary signal amplifier circuit through a tenth resistor (R26); the MIC BIAS pin of the audio amplifier chip is electrically connected to the first end of the eleventh resistor (R25); the second end of the eleventh resistor (R25) is electrically connected to the first end of the twelfth resistor (R27); the second end of the twelfth resistor (R27) is grounded; and the TH pin of the audio amplifier chip is electrically connected to the first end of the twelfth resistor (R27).

5. A fire hydrant monitoring device according to claim 1, characterized in that , the bias voltage circuit comprises a fourth operational amplifier (U3); the output end of the fourth operational amplifier (U3) is used to output the bias voltage; The positive power supply terminal of the fourth operational amplifier (U3) is electrically connected to the power supply; the positive power supply terminal of the fourth operational amplifier (U3) is grounded through a thirteenth capacitor (C18); the negative power supply terminal of the fourth operational amplifier (U3) is grounded; the non-inverting input terminal of the fourth operational amplifier (U3) is electrically connected to the power supply through a thirteenth resistor (R21); the non-inverting input terminal of the fourth operational amplifier (U3) is grounded through a fourteenth resistor (R24) and a fourteenth capacitor (C19) arranged in parallel; the inverting input terminal of the fourth operational amplifier (U3) is electrically connected to the output terminal of the fourth operational amplifier (U3); the output terminal of the fourth operational amplifier (U3) is grounded through a fifteenth capacitor (C22) and a third electrolytic capacitor (C20) arranged in parallel; wherein the positive electrode of the third electrolytic capacitor (C20) is electrically connected to the output terminal of the fourth operational amplifier (U3), and the negative electrode of the third electrolytic capacitor (C20) is grounded.

6. A fire hydrant monitoring device according to any one of claims 1 to 5, characterized in that The data collected by the pressure sensor is connected to the control component via 4-20mA.

7. A fire hydrant monitoring device according to any one of claims 1 to 5, characterized in that ,The fire hydrant monitoring device also includes a communication module; The communication module is communicatively connected to the controller.

8. A fire hydrant, characterized in that: A fire hydrant monitoring device comprising any one of claims 1 to 7.

9. A fire hydrant cap rod, characterized in that: A fire hydrant monitoring device comprising any one of claims 1 to 7.

10. A fire hydrant door cover, characterized in that: A fire hydrant monitoring device comprising any one of claims 1 to 7.

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