Low-power-consumption Bluetooth ultrasonic liquid level detection sensor

Abstract

The utility model discloses a low-power-consumption Bluetooth ultrasonic liquid level detection sensor, and aims to solve the technical problem of reducing the liquid level detection cost of a liquefied gas storage tank. A circuit main board, a fixing support, an ultrasonic transducer, a battery, solid-state coupling silica gel and a magnet are arranged in a shell. The circuit mainboard is provided with an electrostatic protection circuit, a temperature detection circuit, an inclination angle detection circuit, an ultrasonic transducer excitation circuit, an ultrasonic receiving circuit, a signal amplification circuit, a signal frequency processing circuit, a signal shaping circuit, a Bluetooth communication circuit and a processor. Compared with the prior art, the solid coupling silica gel realizes the coupling of the ultrasonic transducer and the surface of the measured tank body, the maintenance cost is low, the sensor is adsorbed to the bottom of the tank body container by magnetic force, the installation is simple, the ultrasonic distance measurement and measurement precision and stability are high, the blind area is small, the Bluetooth connection is adopted, and wiring is not needed. The host can be placed at any position within a sensor Bluetooth signal coverage range, the standby time is long, and the cost is low.

Description

Technical Field

[0001] The utility model relates to a sensor, in particular to a sensor for detecting the liquid level of a liquefied gas tank. Background Art

[0002] Existing methods for detecting the remaining liquid level in liquefied gas tanks generally use pressure gauges and weighing to check the remaining gas volume. Pressure gauges only display pressure values ​​and cannot directly reflect the specific remaining gas volume. Furthermore, different usage environments and conditions may affect the correspondence between pressure and gas volume, resulting in certain errors in the determination. Weighing methods require tools such as scales, which are relatively cumbersome to operate and inconvenient to monitor at any time. These methods for detecting the remaining liquid level in liquefied gas tanks have the following shortcomings: 1. Installation is inconvenient, requiring a hole in the tank; 2. Installation requires gluing and fixing, making maintenance difficult; 3. The use of liquid coupling agent requires regular maintenance; 4. The sensor requires wiring to communicate with the host computer; 5. Wireless communication mostly uses WiFi, which consumes high power and has a short standby time. 6. The battery uses AA batteries, and the magnet uses a ring magnet sensor, which is bulky. 7. The processor and wireless communication chip are separated, resulting in high electronic material costs. These shortcomings lead to high costs for measuring the liquid level in liquefied gas tanks.

[0003] Existing non-contact measurement methods for detecting the remaining level in liquefied gas tanks include infrared ranging, laser ranging, millimeter wave ranging, and ultrasonic ranging. Infrared ranging has strict requirements for ambient light and the color of the object being measured; laser ranging has high requirements for the working environment and is easily affected by light and color; millimeter wave ranging is bulky and expensive; and all cannot penetrate metal, requiring holes to be drilled in the tank for installation, making it unsuitable for use in hazardous tanks such as liquefied petroleum gas. Ultrasonic sensors require the use of liquid coupling agent or AB glue to couple with the tank. Liquid coupling agent is easily volatile and requires regular addition of coupling agent. Once installed, AB glue firmly adheres the sensor to the tank, making it difficult to disassemble and maintain.

[0004] The sensor and host are connected via a cable, requiring installation wiring. The installation distance between the host and sensor is limited by the cable length. This also results in high power consumption and a short battery life in battery-powered applications. Summary of the Invention

[0005] The purpose of this utility model is to provide a low-power Bluetooth ultrasonic liquid level detection sensor. The technical problem to be solved is to reduce the cost of liquefied gas tank liquid level detection, read the remaining liquid level in the liquefied gas tank anytime and anywhere within the signal coverage range, and provide an interface for the intelligentization of liquefied gas tanks.

[0006] The utility model adopts the following technical solution: a low-power Bluetooth ultrasonic liquid level detection sensor, provided with a shell, in which a circuit mainboard, a fixing bracket, an ultrasonic transducer, a battery, solid-state coupling silicone and a magnet are arranged; the circuit mainboard is provided with an electrostatic protection circuit, a temperature detection circuit, an inclination detection circuit, an ultrasonic transducer excitation circuit, an ultrasonic receiving circuit, a signal amplification circuit, a signal frequency processing circuit, a signal shaping circuit, a Bluetooth communication circuit and a processor.

[0007] The shell of the utility model is provided with a shell body and a bottom cover, forming a round box-shaped shell, and a hole is opened in the middle of the shell body;

[0008] The ultrasonic transducer is used to send an ultrasonic signal to the liquid surface in the liquefied gas tank after receiving the ultrasonic excitation signal;

[0009] The solid coupling silica gel is installed in the middle opening of the housing body through a fixing bracket and covers the ultrasonic transducer;

[0010] The magnet is used to adsorb the low-power Bluetooth ultrasonic liquid level detection sensor to the bottom of the tank to be tested;

[0011] The fixing bracket is used to fix and install the ultrasonic transducer, the magnet and the solid coupling silica gel;

[0012] The battery is arranged on the ultrasonic transducer and is used to supply power to the circuit main board and the ultrasonic transducer;

[0013] The outer shell of the utility model is in the shape of a round bottle cap, the outer edge of the disc is extended in the circumferential direction perpendicular to the disc, a hole is opened in the middle of the disc, and the bottom cover is disc-shaped and installed on the edge of the extended outer shell.

[0014] The solid coupling silica gel of the utility model is in the shape of a circular plate.

[0015] The utility model comprises two magnets in a short cylindrical shape, which are located on both sides of the ultrasonic transducer. The ultrasonic transducer and the two magnets are installed on the same diameter.

[0016] The fixing bracket of the utility model is in a circular ring shape.

[0017] The battery of the utility model adopts a 200ma button battery.

[0018] The circuit main board of the utility model is in the shape of a circular plate with a hole in the middle.

[0019] The electric protection circuit of the utility model is used to protect the processor and prevent static electricity from entering the processor;

[0020] The temperature detection circuit is used to collect the external temperature;

[0021] The tilt detection circuit detects the tilt angle of the sensor;

[0022] The ultrasonic transducer excitation circuit is used to transmit an ultrasonic excitation signal to the ultrasonic transducer (5) to excite the ultrasonic transducer;

[0023] The ultrasonic receiving circuit is used to receive the ultrasonic echo signal of the ultrasonic transducer (5);

[0024] The signal amplifying circuit is used to amplify the ultrasonic echo signal;

[0025] The signal frequency processing circuit performs frequency screening on the amplified ultrasonic echo signal;

[0026] The signal shaping circuit shapes the ultrasonic echo signal after amplification and frequency screening into an envelope signal and provides it to the processor;

[0027] The Bluetooth communication circuit transmits, receives and amplifies Bluetooth signals between the processor and the Bluetooth host;

[0028] The low-power Bluetooth ultrasonic liquid level detection sensor of the utility model is installed at the bottom of the liquefied gas tank to be detected.

[0029] Compared with the existing technology, the utility model is provided with a solid coupling silicone in the sensor housing to achieve coupling between the ultrasonic transducer and the surface of the tank to be measured. There is no need to add coupling agent regularly, and the maintenance cost is low. The sensor is adsorbed to the bottom of the iron tank container by the magnetic force of the magnet, which is simple to install. With ultrasonic ranging, there is no need to open holes in the tank, and the measurement accuracy and stability are high, and the blind spot is small. With Bluetooth connection, there is no need for wiring, and the host can be placed anywhere within the coverage range of the sensor's Bluetooth signal. The wireless communication technology sampling Bluetooth replaces WiFi, with lower power consumption and long battery standby time. The battery uses a button battery, and the sensor structure is small and thin. The magnet uses two small magnets instead of a large annular magnet, and the sensor structure is further reduced. The selected processor integrates the Bluetooth communication function, saving the material cost of the wireless communication module. The overall cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a structural diagram of the circuit mainboard of the utility model.

[0031] Figure 2 It is an installation diagram of the utility model.

[0032] Figure 3 It is a schematic diagram of the structural decomposition of the present utility model.

[0033] Figure 4 It is the outer appearance drawing of the shell of the present utility model. DETAILED DESCRIPTION

[0034] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0035] like Figure 2 As shown, the present invention's low-power Bluetooth ultrasonic liquid level detection sensor (sensor) 100 includes a housing mounted on the bottom of a liquefied gas tank 200 to detect the liquid level of a 20-40 pound liquefied gas tank. The sensor at the bottom of the tank is wirelessly connected to the user's Bluetooth host 300.

[0036] like Figure 3 and Figure 4 As shown, the housing comprises a housing body 1 and a bottom cover 2. The housing body 1 is shaped like a round bottle cap, with the outer edge of the disc extending circumferentially in a direction perpendicular to the disc, resulting in a concave cross-section at any diameter of the housing body 1. The disc has a hole in the center. The bottom cover 2 is disc-shaped and is mounted on the extended edge of the housing body 1. The housing body 1 and the bottom cover 2 form a round box-shaped housing.

[0037] Inside the housing, there are provided a circuit board 3, a fixing bracket 4, an ultrasonic transducer 5, a battery 6, a solid-state coupling silica gel 7 and two magnets 8.

[0038] The ultrasonic transducer 5 is in the shape of a circular plate and is mounted in the opening in the middle of the housing body 1 through a fixing bracket 4. The ultrasonic transducer 5 is used to send an ultrasonic signal to the liquid level in the liquefied gas tank after receiving the ultrasonic excitation signal.

[0039] The solid coupling silicone 7 is in the shape of a circular plate and is mounted in the middle opening of the housing body 1 through the fixing bracket 4 and covers the ultrasonic transducer 5. The solid coupling silicone 7 is used for coupling between the ultrasonic transducer 5 and the tank under test.

[0040] Two magnets 8 are short cylindrical and are arranged in the housing body 1, on both sides of the ultrasonic transducer 5. The ultrasonic transducer 5 and the two magnets 8 are installed on the same diameter. The magnets 8 are used to adsorb the sensor to the bottom of the tank.

[0041] The fixing bracket 4 is annular and is mounted on the housing body 1 , and is used for fixing and mounting the ultrasonic transducer 5 , two magnets 8 and the solid coupling silica gel 7 .

[0042] The battery 6 is disposed under the ultrasonic transducer 5. The battery 6 is used to power the circuit board 3 and the ultrasonic transducer 5. In this embodiment, the battery 6 is a 200ma button battery.

[0043] The circuit board 3 is in the shape of a circular plate with a hole in the middle.

[0044] like Figure 1As shown, the circuit main board 3 is provided with an electrostatic protection circuit, a temperature detection circuit, a tilt detection circuit, an ultrasonic transducer excitation circuit, an ultrasonic receiving circuit, a signal amplification circuit, a signal frequency processing circuit, a signal shaping circuit, a Bluetooth communication circuit and a processor.

[0045] The electrostatic protection circuit is used to protect the processor from static electricity. In this embodiment, the electrostatic protection circuit adopts the electrostatic protection circuit of the prior art.

[0046] The temperature detection circuit is used to collect the temperature of the outside world (sensor location). In this embodiment, the temperature detection circuit adopts the temperature detection circuit of the prior art.

[0047] The tilt detection circuit detects the tilt angle of the sensor and is used to assist the user in installing and placing the liquefied gas tank by displaying the tilt angle of the tank. In this embodiment, the tilt detection circuit adopts the tilt detection circuit of the prior art.

[0048] The ultrasonic transducer excitation circuit is used to transmit an ultrasonic excitation signal to the ultrasonic transducer 5 to excite the ultrasonic transducer and drive the ultrasonic transducer 5 to operate. In this embodiment, the ultrasonic transducer excitation circuit adopts the ultrasonic transducer excitation circuit of the prior art.

[0049] The ultrasonic receiving circuit is used to receive the ultrasonic echo signal from the ultrasonic transducer 5. In this embodiment, the ultrasonic receiving circuit adopts the ultrasonic receiving circuit of the prior art.

[0050] The signal amplifying circuit is used to amplify the ultrasonic echo signal. In this embodiment, the signal amplifying circuit adopts the signal amplifying circuit of the prior art.

[0051] The signal frequency processing circuit performs frequency screening on the amplified ultrasonic echo signal. In this embodiment, the signal frequency processing circuit adopts the signal frequency processing circuit of the prior art.

[0052] The signal shaping circuit shapes the ultrasonic echo signal after amplification and frequency screening into an envelope signal and provides it to the processor. In this embodiment, the signal shaping circuit adopts the signal shaping circuit of the prior art.

[0053] The Bluetooth communication circuit transmits, receives and amplifies Bluetooth signals between the processor and the Bluetooth host. In this embodiment, the Bluetooth communication circuit adopts the Bluetooth communication circuit of the prior art.

[0054] The processor is used to issue instructions to the ultrasonic transducer excitation circuit and the Bluetooth communication circuit, collect signals from the signal shaping circuit, the temperature detection circuit, the tilt detection circuit, the detection sensor, and the Bluetooth communication circuit, perform signal processing, and output signals to the ultrasonic transducer excitation circuit and the Bluetooth communication circuit. In this embodiment, the processor is a conventional processor.

[0055] The processor is equipped with a Bluetooth communication processing system and an ultrasonic ranging processing system of the prior art, and a system for processing the signals returned by the temperature detection circuit and the tilt detection circuit, which are used to achieve stable liquid level measurement and stable communication with the Bluetooth host via Bluetooth.

[0056] The low-power Bluetooth ultrasonic liquid level detection sensor of this utility model has the following working process:

[0057] a. Power on the sensor to provide power to each circuit.

[0058] b. The processor starts initialization to ensure that all circuits work normally.

[0059] c. Enter hibernation.

[0060] d. Wait for the Bluetooth broadcast time to arrive and then wake up.

[0061] e. The sensor's Bluetooth starts broadcasting and waits for the user's Bluetooth host to connect. If there is a Bluetooth host connection, proceed to step f; otherwise, return to step c.

[0062] f. The sensor's Bluetooth is connected to the user's Bluetooth host.

[0063] g. Wait for the user's Bluetooth host to send a command.

[0064] h. The user's Bluetooth host sends a command to read the liquid level value to the sensor.

[0065] i. The sensor receives the liquid level reading command sent by the user's Bluetooth host via Bluetooth.

[0066] j. The processor sends instructions to the ultrasonic transducer excitation circuit.

[0067] k. The ultrasonic transducer 5 is excited and transmits ultrasonic signals into the tank.

[0068] 1. The ultrasonic transducer 5 waits to receive the ultrasonic signal returned from the tank.

[0069] m. The ultrasonic receiving circuit receives a weak ultrasonic signal from the ultrasonic transducer 5, amplifies it through the signal amplification circuit, and filters out the signal of useful frequency through the signal frequency processing circuit.

[0070] n. After shaping, the signal returns to the processor, which processes and filters the target echo according to the algorithm in the ultrasonic ranging processing system.

[0071] o. Temperature detection circuit, detects the external ambient temperature and feeds it back to the processor.

[0072] p. Tilt angle detection circuit detects the current tilt angle of the sensor and feeds it back to the processor.

[0073] q. The processor calculates the distance value s=v*t / 2 based on the return time of the ultrasonic echo and the external ambient temperature, where s is the distance, v is the speed, and t is the round-trip time from the bottom of the tank to the surface of the liquid.

[0074] r. The processor transmits the calculated value to the user's Bluetooth host via Bluetooth and returns to step f.

[0075] Each circuit on the circuit main board 3 of this embodiment has low power consumption and a standby time of up to 3.7 years.

[0076] This embodiment has a measuring range of 100 cm and a minimum blind area of ​​3 cm, and is suitable for liquefied gas level detection. It has high measurement stability and high accuracy, and meets the requirements for level detection of 20-40 pound liquefied gas tanks.

[0077] This utility model uses non-contact distance measurement, utilizing a sensor mounted at the bottom of the tank being measured. Without opening a hole or damaging the tank, the ultrasonic signal can directly penetrate the liquefied gas tank, obtaining the time value of the ultrasonic signal returning when it reaches the liquid surface inside the tank. The distance from the tank bottom to the liquefied gas surface is calculated, and the current liquid level in the liquefied gas tank is determined, achieving distance measurement from the tank bottom to the liquid surface. The measured information, including the liquid level, temperature, battery charge, and tank tilt angle, is then transmitted via Bluetooth to a Bluetooth-enabled device such as a Bluetooth host or smartphone.

[0078] The utility model uses Bluetooth communication, and the sensor and the Bluetooth host perform data interaction. The communication is stable and reliable, and no wiring is required.

[0079] This embodiment uses a button battery for power and boasts a lightweight design. Two small magnets are located within the circular box-shaped housing, and solid-state silicone coupling is located above the ultrasonic transducer. Installation is complete when the user attaches the sensor to the bottom of the tank using the magnets, connects via Bluetooth, and successfully reads the correct liquid level. Maintenance is simple, reducing installation and maintenance learning curves.

[0080] Ultrasonic ranging is a non-contact detection method. It calculates the distance to the object being measured by combining the time it takes for ultrasonic waves to be emitted from the sound wave source and reflected back to the sound wave source when encountering an obstacle with the speed of sound in liquid. Because ultrasonic waves are not affected by light, color of the object being measured, etc., the measurement is accurate.

[0081] Utilizing Bluetooth communication, this sensor can be easily connected to a variety of Bluetooth-enabled smart devices, eliminating the need for specialized hardware interfaces and sensor docking, resulting in low integration costs. The communication protocol uses the standard Modbus protocol, allowing even Modbus hosts without Bluetooth to easily interact with data by plugging in a Bluetooth transparent transmission device, reducing learning costs.

[0082] The utility model utilizes ultrasonic distance measurement and Bluetooth wireless communication, has low power consumption, simple structure and low cost.

Claims

1. A low-power Bluetooth ultrasonic liquid level detection sensor, characterized by: The low-power Bluetooth ultrasonic liquid level detection sensor is provided with a housing, wherein a circuit mainboard (3), a fixing bracket (4), an ultrasonic transducer (5), a battery (6), a solid-state coupling silica gel (7) and a magnet (8) are provided in the housing; an electrostatic protection circuit, a temperature detection circuit, an inclination detection circuit, an ultrasonic transducer excitation circuit, an ultrasonic receiving circuit, a signal amplification circuit, a signal frequency processing circuit, a signal shaping circuit, a Bluetooth communication circuit and a processor are provided on the circuit mainboard (3).

2. The low-power Bluetooth ultrasonic liquid level detection sensor according to claim 1, characterized in that: The housing is provided with a housing body (1) and a bottom cover (2), forming a round box-shaped housing, and a hole is opened in the middle of the housing body (1); The ultrasonic transducer (5) is used to send an ultrasonic signal to the liquid surface in the liquefied gas tank after receiving the ultrasonic excitation signal; The solid coupling silica gel (7) is installed in the middle opening of the housing body (1) through a fixing bracket (4) and covers the ultrasonic transducer (5); The magnet (8) is used to adsorb the low-power Bluetooth ultrasonic liquid level detection sensor to the bottom of the tank to be tested; The fixing bracket (4) is used for fixing and installing the ultrasonic transducer (5), the magnet (8) and the solid coupling silica gel (7); The battery (6) is arranged on the ultrasonic transducer (5) and is used to supply power to the circuit main board (3) and the ultrasonic transducer (5).

3. The low-power Bluetooth ultrasonic liquid level detection sensor according to claim 2, characterized in that: The outer shape of the shell body (1) is a round bottle cap, the outer edge of the disc is formed by extending in a circumferential direction perpendicular to the disc, and a hole is opened in the middle of the disc. The bottom cover (2) is disc-shaped and is installed on the edge of the extended shell body (1).

4. The low-power Bluetooth ultrasonic liquid level detection sensor according to claim 3, characterized in that: The solid coupling silica gel (7) is in the shape of a circular plate.

5. The low-power Bluetooth ultrasonic liquid level detection sensor according to claim 4, characterized in that: There are two magnets (8) in a short cylindrical shape, located on both sides of the ultrasonic transducer (5), and the ultrasonic transducer (5) and the two magnets (8) are installed on the same diameter.

6. The low-power Bluetooth ultrasonic liquid level detection sensor according to claim 5, characterized in that: The fixing bracket (4) is in the shape of a circular ring.

7. The low-power Bluetooth ultrasonic liquid level detection sensor according to claim 6, characterized in that: The battery (6) is a 200ma button battery.

8. The low-power Bluetooth ultrasonic liquid level detection sensor according to claim 7, characterized in that: The circuit main board (3) is in the shape of a circular plate with a hole in the middle.

9. The low-power Bluetooth ultrasonic liquid level detection sensor according to claim 8, characterized in that: The electrostatic protection circuit is used to protect the processor and prevent static electricity from entering the processor; The temperature detection circuit is used to collect the external temperature; The tilt detection circuit detects the tilt angle of the sensor; The ultrasonic transducer excitation circuit is used to transmit an ultrasonic excitation signal to the ultrasonic transducer (5) to excite the ultrasonic transducer; The ultrasonic receiving circuit is used to receive the ultrasonic echo signal of the ultrasonic transducer (5); The signal amplifying circuit is used to amplify the ultrasonic echo signal; The signal frequency processing circuit performs frequency screening on the amplified ultrasonic echo signal; The signal shaping circuit shapes the ultrasonic echo signal after amplification and frequency screening into an envelope signal and provides it to the processor; The Bluetooth communication circuit transmits, receives and amplifies Bluetooth signals between the processor and the Bluetooth host.

10. The low-power Bluetooth ultrasonic liquid level detection sensor according to claim 1, characterized in that: The low-power Bluetooth ultrasonic liquid level detection sensor is installed at the bottom of the liquefied gas tank to be tested.

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