[0018] The invention includes a power monitoring module, a control module, a drive module, a signal processing module, an ultrasonic sensor, and a wireless module. The power monitoring module is used to provide 24V and 5V DC voltage to the control module, drive module, signal processing module, and ultrasonic sensor. The control module sends a control signal to the drive module. After the signal is processed by the drive module, the signal is converted into an electrical signal capable of driving the ultrasonic sensor, and the sensor is driven to emit ultrasonic waves to perform liquid level measurement. After the echo signal is processed by the ultrasonic sensor, it is converted into an electrical signal again, and the electrical signal is output by the ultrasonic sensor to the signal processing module for identification and processing. The measurement data signal output by the signal processing module is received by the control module, and the control module calculates the measured liquid level value after processing the measurement data signal and outputs it to the wireless module. The wireless module can output the data in two ways, one is output to the fire extinguishing control system, and the other is output to the Bluetooth communication module, so that the measurement personnel can view the level value in real time. In addition, the Bluetooth communication module can also send control signals, which are received by the wireless module and output to the control module for setting initial measurement parameters and performing liquid level measurement. The signal of the control module is divided into two outputs, one is output to the drive module, and the other is output to the wireless module. Among them, the signal output to the drive module is processed and used to control the sensor to perform liquid level measurement, and the signal output to the wireless module is a measurement data signal. The drive module mainly includes: signal conditioning circuit and power amplifier circuit. One output of the control module is used as the input of the signal conditioning circuit, and the output of the signal conditioning circuit is used as the input of the power amplifier circuit. This module can modulate and amplify the power of the control signal sent by the control module to drive the ultrasonic sensor to send ultrasonic signals. Ultrasonic sensors mainly include: electro-acoustic transducers and acoustic-electric transducers. Among them, the output signal of the power amplifier circuit is used as the input signal of the electroacoustic transducer, and the electroacoustic transducer emits ultrasonic waves to perform liquid level measurement. The echo signal is received by the acousto-electric transducer and converted into an electric signal again, and the electric signal is output from the acousto-electric transducer to the signal processing module. The signal processing module mainly includes: A/D conversion module, signal conditioning circuit, signal amplification circuit. Among them, the output signal of the acoustic-electric transducer is used as the input signal of the signal amplifying circuit, the output of the signal amplifying circuit is used as the input of the signal conditioning circuit, and the output of the signal conditioning circuit is used as the input of the A/D conversion module. The output signal is used as the input signal of the control module. This module is used to amplify, pulse shape and filter the output signal of the acoustic-electric transducer, convert it into a digital signal, and send it to the control module for processing and analysis. The wireless module is connected to the control module, the measurement data signal output by the control module is used as the input signal of the wireless module, and the control signal output by the wireless module is used as the input signal of the control module. At the same time, the data signal sent by the wireless module can be transmitted in two ways, one way is transmitted to the fire extinguishing control system, and the other way is output to the wireless communication module. The power monitoring module mainly includes: battery and power conversion and detection module. The battery outputs DC power to the power conversion and detection module, which converts the DC power into 24V and 5V DC voltage by the power conversion and detection module to provide DC power for the control module, drive module, signal processing module and ultrasonic sensor.
[0019] The present invention will be described in more detail below with reference to the accompanying drawings: the present invention includes a power monitoring module, a control module, a driving module, a signal processing module, an ultrasonic sensor, and a wireless module. Among them, the power monitoring module mainly includes a power conversion and detection module, and a battery; the driving module mainly includes a signal conditioning circuit and a power amplifier circuit; an ultrasonic sensor includes an electroacoustic transducer and an acousto-electric transducer; a signal processing module mainly includes A/D Conversion module, signal conditioning circuit and signal amplification circuit. The liquid level measurement system is installed on the outside of the fire extinguishing agent container, and the Bluetooth communication module is handheld, and the measurement personnel can use the module to perform real-time liquid level measurement.
[0020] The power monitoring module mainly includes: battery, power conversion and detection module. Among them, the battery is used to provide DC voltage. The power conversion and detection module can convert the DC output of the battery into 5V and 24V DC voltage. The power conversion and detection module provides 24V voltage for the control module and ultrasonic sensor, and 5V voltage for the drive module and signal processing module. At the same time, the power conversion and detection module has a power detection function, which sends an alarm signal when the power is too low to remind the crew to replace the battery in time.
[0021] The detailed functions of the control module are as follows: (1) The control module periodically wakes up according to the set measurement period, sends control signals and receives measurement data signals, and uploads the measurement data to the fire extinguishing control system in real time for the crew to view; (2) Control When the module is in the wake-up working state, it sends out a certain frequency electrical signal, and sends a signal to the ultrasonic sensor through the drive module to control the electro-acoustic transducer in the ultrasonic sensor to emit an ultrasonic beam for liquid level measurement; (3) The control module passes the signal The processing module receives the electrical signal sent by the sensor, calculates the actual measured liquid level value according to the magnitude of the electrical signal, referring to the comparison value of the liquid level and the electrical signal, and uploads the measurement data through the wireless module; (4) When the control module sleeps, Only the internal timer is in the wake-up state, and the specific sleep time can be set by the Bluetooth communication module.
[0022] Drive module, including signal conditioning circuit and power amplifier circuit. Its function is mainly to process the electrical signal output by the control module so that it can drive the electroacoustic transducer. Specifically, the signal conditioning circuit mainly refers to the pulse modulation circuit, which processes the pulse signal sent by the control module to meet the requirements of the electro-acoustic transducer. The power amplifier circuit amplifies the power of the modulated signal so that it can drive the electro-acoustic transducer and send an ultrasonic signal.
[0023] The signal processing module mainly includes an A/D conversion module, a signal conditioning circuit, and a signal amplification circuit. The entire signal processing module can process the electrical signal transmitted by the acoustic-electric transducer so that it can be directly read and analyzed by the control module. The specific instructions are as follows: (1) A/D conversion module, which can convert the detected voltage or The current signal analog quantity is converted into an equivalent digital quantity that can be recognized by the control module, and the digital quantity has a corresponding corresponding relationship with the liquid level value, and the actual measured liquid level value can be obtained through the calculation and processing of the control module. (2) Signal conditioning circuit, which mainly includes pulse shaping circuit and band-pass filter circuit. The pulse shaping circuit can convert the unstable waveform signal transmitted by the acoustic-electric transducer into a regular waveform signal that meets the requirements for subsequent signal analysis and processing . Since the ultrasonic signal will be affected by the environment during the actual measurement, the waveform signal received and transmitted by the acousto-electric transducer may include different frequency bands. The band-pass filter circuit can remove other frequency band signals that are not related to liquid level measurement. The control module performs identification and processing. (3) The signal amplification circuit is used to amplify the amplitude of the waveform signal transmitted by the acoustic-electric transducer. This process can transform the weak signal received by the sensor into a signal that can be identified and processed and meets the requirements. Does not affect the measured value of the liquid level of the fire extinguishing agent container.
[0024] Ultrasonic sensor, this part is mainly composed of electro-acoustic transducer and acoustic-electric transducer. Among them, the electro-acoustic transducer is used to convert electrical signals into ultrasonic waves and emitted outwards for liquid level measurement; the acousto-electric transducer is used to receive echo signals, convert them into electrical signals, and transmit them to the control through the signal processing module The module performs calculation processing and obtains the level value. The ultrasonic sensor adopts an integrated transceiver, that is, the electroacoustic transducer and the acoustic-electric transducer are integrated on an ultrasonic probe. The sensor meets the measurement requirements and the actual installation requirements of the high-pressure airtight fire extinguishing agent container with the sensor installation position at the bottom of the tank.
[0025] The wireless module is used to receive control signals and send measurement data signals. The detailed description is as follows: (1) The wireless module and the control module have the same wake-up cycle. When the control module wakes up, the wireless module is awakened synchronously, receives the measurement data signal transmitted by the control module, and uploads the data to the fire extinguishing control system. (2) During the sleep period of the control module, the wireless module is in a low power consumption state, and the low power consumption state refers to periodically and automatically wake up to detect whether there is a control signal, which is sent by the Bluetooth communication module. If there is a control signal, it will wake up immediately and enter the normal working state for data receiving and sending. If there is no control signal, it will immediately enter the sleep state and wait for the next wake-up cycle to be awakened. (3) The Bluetooth communication module is a control terminal held by the surveyor. It sends a control signal to the control module through the wireless module to perform liquid level measurement and transmits the data to the display screen of the Bluetooth communication module for the surveyor to view. The specific functions of the Bluetooth communication module are as follows: a. The Bluetooth communication module can actively wake up the control module by sending a control signal to perform a single level measurement work in addition to the periodic level measurement, so that the crew can check the extinguishing agent container liquid at any time B. The Bluetooth communication module has a display module that can display the measured liquid level and remind the measuring personnel when the liquid level is lower than the warning level; c. The Bluetooth communication module contains a control panel for actively waking up the control module and Set the initial measurement parameters.
[0026] The working process and working principle of the present invention are as follows:
[0027] (1) The power monitoring module uses the battery to provide DC power to the entire system. The measurement personnel send control signals to the control module through the handheld Bluetooth communication module, set the measurement period of the system and the initial parameters of the measurement, and turn on the system to make it work . (2) When the system is working, the control module is in a periodic wake-up state. For example, if the measurement period is set to one day, the control module will automatically wake up at a specific time each day and send a control signal to the drive module. The drive module processes and amplifies the signal sent by the control module to enable it to drive the electro-acoustic transducer. The electroacoustic transducer converts electrical signals into mechanical waves, namely ultrasonic waves, and emits them to the outside. After the ultrasonic waves are reflected by the gas-liquid interface, the echo is received by the acoustic-electric transducer. The acoustic-electric transducer converts the acoustic wave signal into an electric signal and sends it to the signal processing module. The signal processing module amplifies, reshapes and filters the signal, which is processed by the A/D conversion module and converted into a digital signal which is read by the control module. The control module can calculate the actual measured liquid level value according to the magnitude of the read electrical signal, referring to the comparison value of the signal size and the liquid level, and the measured data is uploaded to the fire extinguishing control system in time through the wireless module. At this point, a working cycle of the system ends and enters a sleep state, waiting for the next wake-up cycle to be awakened. The operator can view the daily liquid level measurement value on the display module of the fire extinguishing system. (3) When the system is in a dormant state, that is, if it is not awakened, its wireless module will automatically wake up periodically. The wake-up period is much shorter than the wake-up period of the liquid level monitoring system to detect whether there is a control signal sent by the Bluetooth communication module. If there is, the control module will be awakened immediately to make it enter the normal working state for liquid level measurement. If not, it will immediately sleep and wait for the next awakening cycle to be awakened. This function enables the surveyor to measure and view the level of the fire extinguishing agent container at any time during the dormant period of the system, which further guarantees the fire safety of ships.
