A wireless alarm device for shutdown pipeline based on eddy current electromagnetic induction

Abstract

The application discloses a kind of based on eddy current electromagnetic induction's heat supply pipeline wireless alarm device, it is related to heat supply pipeline monitoring technical field, including prefabricated induction coil assembly, signal conditioning circuit board, main control chip, wireless communication module and protective shell, prefabricated induction coil assembly includes waterproof insulating sheath and the induction coil sealed in it, waterproof insulating sheath outer wall is fixedly connected with the fastening member fixed in the outer wall of heat supply pipeline, signal conditioning circuit board is integrated with instrument amplifier, rectifier filter circuit and comparator, after the induction voltage signal after amplification and rectifier filter is compared with threshold voltage, the level signal indicating pipeline on-off state is output, main control chip judges whether heat failure occurs according to the duration that level signal is continuously lower or continuously higher than threshold voltage, and sends alarm signal when judging fault, the present application does not need to open hole installation on pipeline, with low false alarm rate and low power consumption characteristics.

Description

Technical Field

[0001] This invention relates to the field of heating pipeline monitoring technology, and in particular to a wireless alarm device for a heating pipeline in operation that is shut down based on eddy current electromagnetic induction. Background Technology

[0002] Heating networks are a crucial component of urban infrastructure. Real-time monitoring of hot water flow within these pipelines is essential for ensuring heating quality and promptly detecting heating outages. In centralized heating systems, localized heating outages due to pipeline leaks, accidental valve closures, or pump station malfunctions are common. Timely detection and precise location of these faults can significantly shorten repair response times, reduce user complaints, and minimize heating losses.

[0003] Currently, the monitoring of the on / off status of heating pipelines mainly adopts the following methods: First, ultrasonic flow meters: This method measures flow velocity by the time difference of ultrasonic waves propagating through the fluid in the pipe, thus determining whether water is flowing through the pipe. However, ultrasonic flow meters are usually installed by insertion, requiring holes to be drilled in the pipe. Installation necessitates shutting down heating, affecting users' normal heating. Furthermore, the ultrasonic transducer is easily scaled up when immersed in hot water for extended periods, leading to signal attenuation or even failure. Regular disassembly and cleaning are required, resulting in high maintenance costs.

[0004] Second, mechanical flow switches: This method uses moving parts such as impellers or targets, utilizing the impact force of water flow to drive the mechanical structure, thereby triggering a switching signal. However, the turbulent water flow in heating pipelines can easily cause the impellers or targets to vibrate, leading to frequent false triggers. Actual operational statistics show that the false alarm rate of mechanical flow switches in heating networks is as high as 28%. Numerous false alarms severely consume the time and energy of maintenance personnel, reducing operational efficiency. Furthermore, the moving parts are subjected to long-term water flow impact, resulting in severe wear and tear and a limited service life.

[0005] Third, pressure transmitters: This method determines the on / off status by detecting changes in water pressure within the pipeline. However, heating networks are systems with significant pressure fluctuations; pump start-ups, shutdowns, and valve adjustments can all cause instantaneous pressure fluctuations, easily leading to misjudgments. Furthermore, pressure transmitters also require installation through openings in the pipeline, and the pressure tapping pipe is prone to blockage, necessitating frequent maintenance.

[0006] However, in addition to their individual shortcomings, the aforementioned existing technologies also share the following common problems: First, the installation method disrupts pipeline integrity. Whether it's an ultrasonic flow meter, a mechanical flow switch, or a pressure transmitter, installation requires drilling holes in the pipeline or cutting off sections. This necessitates shutting down heating during construction, impacting user experience, and poses a risk of corrosion and leakage at the drilling points. Second, most existing monitoring equipment uses wired power and transmission, making deployment difficult in scenarios without mains power, such as valve wells and trenches. While some devices integrate wireless communication, their single communication standard cannot adapt to varying signal coverage conditions. Third, when these devices are deployed in the field or unattended areas, they face the risk of dismantling, theft, or malicious damage, leading to equipment loss, monitoring blind spots, and compromised data continuity. Finally, the lack of effective anti-interference mechanisms prevents the effective identification of instantaneous flow disturbances such as water hammer and turbulence, resulting in numerous invalid alarms.

[0007] In addition, there are a large number of idle, standby, or abandoned pipes in the heating network. These pipes are isolated from the main network by valves and are normally dry. However, in actual operation, there are instances of unscrupulous individuals opening the valves of idle pipes to steal hot water, and there are also cases of accidental water flow in idle pipes due to valve leakage or misoperation. If abnormal water flow events in idle pipes cannot be effectively monitored, heating companies will face problems such as heat loss, inaccurate metering, and user disputes. Therefore, this invention proposes a wireless alarm device for heating outage pipes based on eddy current electromagnetic induction to solve the problems existing in the prior art. Summary of the Invention

[0008] To address the aforementioned problems, the present invention aims to propose a wireless alarm device for heating outage pipelines based on eddy current electromagnetic induction. This invention can simultaneously achieve non-destructive and rapid installation, low false alarm detection, low-power wireless communication, and anti-tamper protection for the equipment, thereby solving the problems existing in the prior art.

[0009] To achieve the objectives of this invention, the invention is implemented through the following technical solution: a wireless alarm device for a heating outage pipeline based on eddy current electromagnetic induction, comprising: A prefabricated induction coil assembly includes a waterproof insulating sleeve and an induction coil sealed within the waterproof insulating sleeve. The outer wall of the waterproof insulating sleeve is fixedly connected with a fastening member for detachably fastening the waterproof insulating sleeve to the outer wall of a heating pipe. The signal conditioning circuit board integrates an instrumentation amplifier, a rectifier filter circuit, and a comparator. The differential input terminal of the instrumentation amplifier is electrically connected to the output terminal of the induction coil and is used to differentially amplify the induced voltage signal output by the induction coil. The input terminal of the rectifier filter circuit is electrically connected to the output terminal of the instrumentation amplifier and converts the differentially amplified AC induced voltage signal into a DC voltage signal. The comparator has a first input terminal and a second input terminal. The first input terminal is connected to the DC voltage signal, and the second input terminal is connected to a threshold voltage. The comparator compares the amplitude of the DC voltage signal with the threshold voltage and outputs a level signal representing the on / off state of the pipeline based on the comparison result. The main control chip is electrically connected to the output of the comparator and receives the voltage level signal. It then determines whether the pipeline is experiencing an abnormal state based on the duration the voltage level signal remains below or above a threshold voltage. When the pipeline is in normal water flow, the DC voltage signal amplitude is higher than the threshold voltage, the comparator outputs a high-level signal, and the main control chip determines that the pipeline is in normal condition. When a pipeline in use experiences a heating outage, the DC voltage signal amplitude is lower than the threshold voltage, the comparator outputs a low-level signal, and the main control chip determines whether a heating outage fault has occurred based on the duration of the low-level signal. When an idle pipeline is in a normal, waterless state, the DC voltage signal amplitude is lower than the threshold voltage, the comparator outputs a low-level signal, and the main control chip determines that the pipeline is in normal condition. When an idle pipeline experiences abnormal water flow, the DC voltage signal amplitude is higher than the threshold voltage, the comparator outputs a high-level signal, and the main control chip determines whether an abnormal water flow event has occurred based on the duration of the high-level signal. The wireless communication module is electrically connected to the main control chip and is woken up when the main control chip determines that the pipeline has a heat outage fault, and sends a wireless alarm signal to the cloud-based centralized platform management system. The protective housing has a waterproof interface for the lead wire of the induction coil to pass through, and the signal conditioning circuit board, the main control chip and the wireless communication module are all sealed in the inner cavity of the protective housing.

[0010] A further improvement is that the fastening component is a corrosion-resistant elastic strap, which is connected to both ends of the waterproof insulating sheath and is spirally wound and fastened to the outer wall of the heating pipeline.

[0011] A further improvement is that the fastening component is a threaded fixing base, which includes two semi-annular clips and a bolt. The two semi-annular clips are engaged and clamped to the outer wall of the heating pipe. The two semi-annular clips are locked together by the bolt. The waterproof insulating sleeve is fixed to the threaded fixing base by a clip.

[0012] A further improvement is that the induction coil is formed by winding high-temperature resistant insulated enameled wire, the wire diameter of which is 0.1mm to 0.3mm, and the number of turns of the induction coil is 500 to 2000.

[0013] A further improvement is that the threshold voltage can be customized by adjusting the potentiometer.

[0014] A further improvement is that the main control chip has a built-in anti-shake timing program, which determines the shielding state as abnormal when the duration for which the level signal is continuously lower or higher than the threshold voltage is less than a preset duration.

[0015] A further improvement is that the wireless communication module is a three-mode adaptive communication module, which integrates a LoRa communication module, an NB-IoT communication module, and a 4G communication module. The three-mode adaptive communication module automatically selects one of the LoRa communication module, NB-IoT communication module, and 4G communication module to send a wireless alarm signal based on the communication signal strength in the current environment. Multiple alarm devices upload alarm signals to a cloud-based centralized platform management system via their respective wireless communication modules. The cloud-based centralized platform management system includes an equipment filing and management module, a fault location GIS positioning module, and a status statistics module. The equipment filing and management module is used to input the device ID and corresponding installation location information of each alarm device. The fault location GIS positioning module is used to mark the fault location on a GIS map based on the installation location information associated with the device ID after receiving the alarm signal. The status statistics module is used to classify and statistically analyze the abnormal status events reported by each alarm device.

[0016] A further improvement is that it also includes a power supply unit, which is disposed in the inner cavity of the protective housing and is electrically connected to the signal conditioning circuit board, the main control chip and the wireless communication module respectively. The power supply unit includes an external power input terminal and a solid-state lithium battery. The DC voltage input range of the external power input terminal is DC3.3V to DC12V. The power supply unit has three power supply modes: External power input terminal independent power supply mode, solid-state lithium battery independent power supply mode, external power input terminal and solid-state lithium battery dual power redundant power supply mode; In the dual-power redundant power supply mode, the power supply unit prioritizes supplying power to the outside via the external power access terminal. When the input voltage of the external power access terminal is lower than the preset undervoltage threshold, the power supply unit seamlessly switches to power supply via a solid-state lithium battery.

[0017] A further improvement is that the power supply unit also includes a voltage regulator chip, which is connected to the external power input terminal and the output terminal of the solid-state lithium battery. The voltage regulator chip stabilizes the output voltage of the power supply unit to DC 3.3V.

[0018] A further improvement is that the signal conditioning circuit board, the main control chip, and the wireless communication module are integrated in the inner cavity of the protective housing via surface mount technology. A temperature sensor is provided on the outer wall of the protective housing, and an anti-tamper monitoring unit is also provided in the inner cavity of the protective housing. The temperature sensor and the anti-tamper monitoring unit are electrically connected to the main control chip. When the main control chip determines that the pipeline is in an abnormal state and wakes up the wireless communication module, it sends the temperature signal along with the alarm signal to the cloud-based centralized platform management system. The anti-tamper monitoring unit includes a vibration sensor, a displacement sensor, and a physical anti-tamper switch. The vibration sensor detects the vibration impact on the protective housing, the displacement sensor detects the spatial displacement of the protective housing, and the physical anti-tamper switch is set at the open / closed position of the protective housing. When the main control chip outputs an abnormal level signal from any one of the vibration sensor, displacement sensor, or physical tamper switch, it wakes up the wireless communication module to send an anti-theft alarm signal.

[0019] The beneficial effects of this invention are as follows: (1) This invention enables non-destructive and rapid installation. By using prefabricated induction coil components, i.e., using a factory-prefabricated integrated sealed structure, there is no need for on-site winding, drilling holes in the pipeline, or heating shutdown for construction. The prefabricated coil components are fixed to the outer wall of the pipeline by anti-corrosion elastic straps or threaded fixing bases. The installation time is short for a single person and a single device, the installation efficiency is fast, and there are no problems of pipeline corrosion and probe scaling.

[0020] (2) This invention employs a dual anti-interference mechanism combining hardware and software. At the hardware level, the differential input terminal of the instrumentation amplifier is directly connected to the induction coil to suppress spatial common-mode electromagnetic interference at the source. At the software level, the main control chip has a built-in anti-shake timing program that shields voltage fluctuations caused by instantaneous water hammer, turbulence, etc. It only determines a real fault when the level signal is continuously abnormal for more than a preset duration, effectively reducing the false alarm rate. At the same time, through the bidirectional judgment logic of the main control chip for the level signal being continuously lower or higher than the threshold voltage, the same device is applicable to both the detection of heat interruption and flow interruption in in-use pipelines (forward mode) and the detection of abnormal water flow in idle pipelines (reverse mode). There is no need to change the hardware structure; the detection mode can be switched simply by selecting the threshold setting direction, greatly expanding the applicability of the device.

[0021] (3) The wireless communication module of the present invention integrates three communication standards: LoRa, NB-IoT and 4G. It can automatically select the best communication link according to the signal strength in the current environment, and take into account the three needs of closed valve well penetration communication, long-distance wide-area communication in urban and suburban areas and high-speed uploading of emergency faults, so as to realize seamless networking of the entire pipeline network.

[0022] (4) The present invention provides three power supply modes: external power supply alone, internal battery power supply alone, and dual power supply redundancy of external power and battery. Compared with the existing products that replace batteries every year, the frequency of maintenance and labor costs are greatly reduced.

[0023] (5) This invention can be used in conjunction with on-site receiving alarm units and cloud-based centralized platforms to achieve functions such as automatic fault location, online viewing of equipment status, and automatic generation of operation and maintenance reports, thereby helping heating companies upgrade intelligently. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structural framework of the present invention.

[0025] Figure 2 This is a schematic diagram of the internal circuit module layout of the protective housing of the present invention. Detailed Implementation

[0026] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0027] The following embodiments involve induction coils. The working principle of using induction coils to detect the on / off state of a pipeline is as follows: Hot water in heating pipes is a conductive medium. During normal flow, continuous eddies form on the inner wall of the pipe. The dynamic changes of these eddies cause periodic changes in the magnetic flux inside the prefabricated integrated induction coil, which in turn generates a stable and weak AC induced electromotive force. The prefabricated induction coil uses an integral sealed package and a uniform turn layout, resulting in superior magnetic field induction consistency and stability compared to on-site manual winding structures, and stronger resistance to deformation and displacement. When the pipe stops heating and the water flow stops, the eddies inside the pipe completely disappear, the magnetic flux of the induction coil tends to stabilize, and the induced electromotive force rapidly decays to an extremely low value. This invention distinguishes between normal water supply conditions and heating / flow interruption fault conditions by accurately capturing the amplitude changes of the induced electromotive force, achieving non-contact, non-destructive, and precise monitoring.

[0028] Based on the above working principle, the alarm device of the present invention has two detection modes: Forward detection mode: Applicable to pipelines in normal operation. When the pipeline is flowing with water, the induced electromotive force (EMF) is at a high amplitude; after the flow is interrupted, the induced EMF drops to a low value. When the main control chip monitors the signal level and it transitions from high to low for more than a preset duration, it determines that a heat outage and flow interruption fault has occurred.

[0029] Reverse detection mode: Applicable to idle pipelines that have been out of service for a long time. In the normal waterless state of the pipeline, the induced electromotive force is at an extremely low amplitude. After abnormal water flow, the induced electromotive force rises to a higher amplitude. When the main control chip monitors the signal level, and the signal changes from low to high and remains high for more than a preset duration, it is determined to be an abnormal water flow event (heat theft or accidental valve opening).

[0030] Both detection modes are implemented using the same hardware structure, requiring only different judgment logic directions to be set according to the pipeline's operational status.

[0031] Example 1 according to Figures 1-2 As shown, this embodiment provides a wireless alarm device for heating outage pipelines based on eddy current electromagnetic induction, applied to a DN50 galvanized heating branch pipeline in an underground pipe trench of a residential community. The installation area has no mains power supply, high ambient temperature and humidity, and the water temperature inside the pipeline is approximately 60℃~70℃, resulting in frequent water hammer impacts. It includes: Prefabricated induction coil assembly: Utilizing an elastic spiral binding structure. The induction coil is formed by winding 1200 turns of 0.15mm diameter high-temperature resistant insulated enameled wire, completely sealed within a waterproof insulating sheath. Corrosion-resistant elastic binding straps are attached to both ends of the waterproof insulating sheath. During installation, the prefabricated induction coil assembly is attached to the outer wall of the heating pipe, and the corrosion-resistant elastic binding straps at both ends are spirally wound around the pipe's circumference. The elasticity of the binding straps tightly secures the waterproof insulating sheath to the pipe's outer wall. The entire installation process requires no drilling into the pipe and no shutdown of the heating system; it can be completed by a single person within 30 seconds.

[0032] The signal conditioning circuit board integrates an instrumentation amplifier, a rectifier-filter circuit, and a comparator. The differential input of the instrumentation amplifier is electrically connected to the output of the induction coil via leads, differentially amplifying the millivolt-level AC induced voltage signal output by the induction coil to suppress common-mode electromagnetic interference generated by power lines and frequency converters within the trench. The rectifier-filter circuit, consisting of a rectifier bridge and an RC filter circuit, converts the differentially amplified AC signal into a stable DC voltage signal. This DC voltage signal is connected to the first input of the comparator, and the threshold voltage is connected to the second input via a potentiometer. In this embodiment, the threshold voltage is set to 0.6V by adjusting the potentiometer.

[0033] Main control chip: A low-power 8-bit microcontroller is selected, with a sleep power consumption of less than 5μA. Correspondingly, the main control chip has a built-in anti-jitter timing program with a preset duration of 30 seconds. The main control chip then continuously receives the level signal output by the comparator. When the level signal remains below the threshold voltage for 30 seconds, it is determined to be a real heat stop fault. If the low level lasts for less than 30 seconds and then returns to a high level, it is determined to be a momentary disturbance such as water hammer or turbulence, and the heat stop fault judgment result is masked, and no alarm is triggered.

[0034] Wireless communication module: It adopts NB-IoT communication module and relies on the operator's wide area network to upload alarm signals to the cloud platform. The wireless communication module is normally in a deep sleep state and is only awakened when the main control chip determines that the pipeline has a heat stop failure. After sending a wireless alarm signal, it immediately re-enters sleep mode.

[0035] Power supply unit: Employs a dedicated solid-state lithium battery power supply mode, where the solid-state lithium battery is a 3.7V industrial-grade lithium-ion battery with a nominal capacity of 15Ah. The power supply unit incorporates an AMS1117-3.3V voltage regulator chip to stabilize the battery voltage at DC 3.3V, providing power to the signal conditioning circuit board, main control chip, and wireless communication module.

[0036] Protective Housing: IP67 waterproof, dustproof, and explosion-proof sealed housing. All circuit components are integrated into the housing cavity using surface mount technology. A waterproof interface is provided on the housing for the induction coil leads to pass through; a sealing ring ensures a waterproof seal between the leads and the waterproof interface. The protective housing is fixed to a bracket on the side wall of the pipe.

[0037] Anti-tamper monitoring unit: Located inside the protective housing, it includes a vibration sensor, a displacement sensor, and a physical anti-tamper switch, all of which are electrically connected to the main control chip.

[0038] Furthermore, a temperature sensor is installed on the outer wall of the protective housing. The temperature sensor and the anti-tamper monitoring unit are electrically connected to the main control chip. When the main control chip determines that the pipeline is in an abnormal state and wakes up the wireless communication module, it sends the temperature signal along with the alarm signal to the cloud-based centralized platform management system, allowing maintenance personnel to remotely verify the pipeline status and improve the accuracy of problem diagnosis.

[0039] The temperature sensor is a platinum resistance temperature sensor, which is mounted on the outer wall of the protective housing. The temperature sensor is electrically connected to the main control chip and is used to collect the temperature signal of the outer wall of the heating pipe and transmit it to the main control chip. The temperature measurement range of this sensor is -20℃ to +150℃, and the measurement accuracy in the 0℃ to 100℃ range is ±1℃.

[0040] During work: When the pipeline is in normal heating and water flow, the induced voltage output by the induction coil, after signal conditioning, is input to the first input terminal of the comparator with a DC voltage signal amplitude of 1.8V. This value is higher than the threshold voltage by 0.6V, and the comparator outputs a high-level signal. Simultaneously, the temperature sensor collects the temperature signal of the outer wall of the pipeline in real time. Under normal water flow conditions, the outer wall temperature of the pipeline is maintained between 60℃ and 70℃. The temperature sensor transmits the collected temperature signal to the main control chip after analog-to-digital conversion. If the current temperature value is higher than the lower limit of the temperature threshold set internally by the main control chip (35℃), the main control chip records the temperature status as "normal." Upon receiving the high-level signal and combining it with the "normal" temperature status, the main control chip determines that the pipeline status is normal, and the entire unit maintains a low-power sleep state, with only the eddy current detection of the induction coil, the temperature sensor, and the anti-tamper monitoring unit continuously operating.

[0041] When the pipeline experiences a heating outage due to an accidental valve closure, the water flow and eddy currents disappear, causing a significant drop in the induced voltage output by the induction coil. After signal conditioning, the DC voltage signal amplitude drops to 0.2V, below the threshold voltage of 0.6V, causing the comparator output to switch from high to low. Upon detecting this transition, the main control chip initiates the anti-jitter timing program. Simultaneously, the temperature sensor continuously collects the temperature signal from the outer wall of the pipeline. After the heating outage, the temperature of the outer wall gradually decreases from the moment of heating interruption. The temperature signal collected by the temperature sensor gradually decreases from 60℃ to 70℃ to the ambient temperature (approximately 25℃), below the lower temperature threshold of 35℃. The temperature sensor transmits the decreased temperature signal to the main control chip, which records the temperature status as "abnormal (low temperature)".

[0042] If the low-level signal persists for 30 seconds without recovery, the main control chip determines it to be a genuine heating failure based on the signal level and immediately wakes up the NB-IoT communication module. The main control chip packages the device ID, heating failure code, and the current temperature value collected by the temperature sensor together and sends it to the cloud platform through the NB-IoT communication module.

[0043] After receiving the alarm message, the cloud platform parses the device ID, heating outage fault code, and temperature value. If the temperature value is below the lower limit of the temperature threshold of 35℃, the cloud platform marks the fault location with a red icon on the GIS map and adds auxiliary information such as "The pipe outer wall temperature has dropped to XX℃, judged as a heating outage fault" to the maintenance work order. After receiving the work order, maintenance personnel can remotely confirm that the alarm is a genuine heating outage fault and not a false alarm caused by electrical interference based on the temperature data. If the temperature value in the alarm message received by the cloud platform is still above the lower limit of the temperature threshold of 35℃, the cloud platform adds a prompt "Temperature data abnormal, please verify on-site" to the maintenance work order, prompting maintenance personnel to pay attention to the status of the temperature sensor.

[0044] During operation, the water hammer impact caused by the start and stop of the water pump causes the output voltage of the induction coil to drop momentarily. The comparator outputs a brief low-level signal, but the low level lasts only 3 to 5 seconds, which does not reach the preset duration of 30 seconds of the anti-shake timing program. The anti-shake timing program is then reset to zero and no alarm is triggered.

[0045] When the protective housing is pried open, the vibration sensor outputs an abnormal level signal, and the main control chip immediately generates an anti-theft alarm message, waking up the NB-IoT communication module to upload the anti-theft alarm signal. When the protective housing is forcibly moved from its installation position, the displacement sensor outputs an abnormal level signal, similarly triggering the anti-theft alarm.

[0046] During six consecutive months of real-world testing, the equipment experienced three actual heating outages and 17 water hammer disturbances caused by pump start-stop cycles. All three heating outages correctly triggered alarms, and all 17 water hammer disturbances were correctly masked by the anti-shake timing program, resulting in a 0% false alarm rate. Battery voltage monitoring showed sufficient charge, with an estimated battery life of 3-6 years.

[0047] Example 2 according to Figures 1-2 As shown, this embodiment provides a wireless alarm device for a heating outage pipeline based on eddy current electromagnetic induction, applied to a DN300 pipeline on a long-distance heating trunk line in a suburban area. The pipeline is laid in an area without mains power supply, with some sections located in underground valve wells and others laid overhead. The pipeline pump station is periodically started and stopped, resulting in severe water hammer effects, and the outdoor environment poses a risk of equipment theft. It includes: Prefabricated induction coil assembly: Utilizing a threaded base clamping structure, the induction coil is formed by winding 1500 turns of 0.2mm diameter high-temperature resistant insulated enameled wire, and is entirely sealed within a waterproof insulating sheath. The threaded fixing base includes two semi-annular clips and bolts. During installation, the two semi-annular clips are first aligned and clamped against the outer wall of the heating pipe. The bolts are then passed through the mounting ears of the two semi-annular clips and tightened, locking the threaded fixing base securely to the outer wall of the heating pipe. Finally, the waterproof insulating sheath covering the induction coil is fixed to the threaded fixing base using the clips.

[0048] Signal conditioning circuit board: Similar to Embodiment 1, it integrates an instrumentation amplifier, a rectifier-filter circuit, and a comparator. The instrumentation amplifier differentially amplifies the induced voltage signal output from the induction coil, the rectifier-filter circuit converts the AC signal into a DC voltage signal, and the comparator compares the amplitude of the DC voltage signal with the threshold voltage and outputs a level signal. In this embodiment, because the DN300 pipe has a larger diameter and the water flow conditions are different from those of the DN50 pipe, the threshold voltage is adjusted to 0.8V by adjusting the potentiometer.

[0049] Main control chip: A low-power 32-bit MCU is selected. This main control chip has a built-in anti-shake timing program with a preset duration of 30 seconds.

[0050] Wireless Communication Module: This is a tri-mode adaptive communication module, integrating LoRa, NB-IoT, and 4G communication modules. During device initialization, the tri-mode adaptive communication module sequentially scans the signal strength of each communication module's frequency band. For devices installed in underground valve wells, due to the shielding effect of the well cover, LoRa signals have better penetration than NB-IoT and 4G, automatically selecting the LoRa communication module to communicate with the nearest gateway. For devices installed in overhead pipeline sections, located in remote areas without LoRa gateway coverage, it automatically switches to the NB-IoT communication module to upload data via the operator's base station. In the event of serious faults such as main pipeline rupture, the 4G communication module achieves fault reporting within seconds using high-speed transmission.

[0051] Power Supply Unit: Employs a dual-power redundant power supply mode. An external small photovoltaic power supply (output DC5V) serves as the main power supply, connected to the device via the external power input terminal; a built-in solid-state lithium battery (3.7V, 20Ah) serves as the backup power supply. The power supply unit includes an AMS1117-3.3V voltage regulator chip and a power switching circuit. The voltage detection comparator in the power switching circuit monitors the input voltage of the external power input terminal in real time. When the photovoltaic power supply output voltage is higher than the preset undervoltage threshold (DC3.0V), the power switching circuit connects the photovoltaic power supply to the input terminal of the voltage regulator chip while disconnecting the solid-state lithium battery; when the photovoltaic power supply output voltage drops below DC3.0V due to nighttime or continuous cloudy / rainy weather, the voltage detection comparator determines that the external power supply is undervoltage, and the power switching circuit disconnects the photovoltaic power supply and connects the solid-state lithium battery within 1 millisecond. The voltage at the output terminal of the voltage regulator chip does not drop, and the main control chip does not reset.

[0052] Protective housing: Same as in Example 1, it is an IP67 waterproof, dustproof and explosion-proof sealed housing, with all circuitry integrated into the inner cavity of the housing.

[0053] Anti-tamper monitoring unit: Same as in Embodiment 1, including vibration sensor, displacement sensor and physical anti-tamper switch.

[0054] Furthermore, a temperature sensor is installed on the outer wall of the protective housing. The temperature sensor and the anti-tamper monitoring unit are electrically connected to the main control chip. When the main control chip determines that the pipeline is in an abnormal state and wakes up the wireless communication module, it sends the temperature signal along with the alarm signal to the cloud-based centralized platform management system, allowing maintenance personnel to remotely verify the pipeline status and improve the accuracy of problem diagnosis.

[0055] The temperature sensor used is a platinum resistance temperature sensor, which differs from the one in Embodiment 1 in that it is mounted on the outer wall of the threaded fixing base. During installation, the temperature sensor maintains close contact with the outer wall of the pipe to collect the temperature signal of the DN300 pipe outer wall. The main control chip internally sets a lower limit of the temperature threshold to 40℃ (the threshold is adjusted upwards accordingly for long-distance heating trunk lines where the water temperature is higher). During work: When the pipeline is flowing normally, the comparator outputs a high level, and the temperature signal of the outer wall of the pipeline collected by the temperature sensor is maintained between 85℃ and 95℃, which is 40℃ higher than the lower limit of the temperature threshold. The main control chip records the temperature status as "normal", determines that the pipeline status is normal, and the whole machine goes into sleep mode.

[0056] When a pipeline pump station starts or stops, causing a severe water hammer impact, the output voltage of the induction coil drops sharply and the comparator outputs a brief low-level signal. The water hammer impact lasts for about 3 to 8 seconds before recovering. Since the duration of the low level is less than the preset 30-second duration of the anti-shake timing program, the main control chip blocks the judgment result and does not trigger an alarm.

[0057] When a genuine heating outage occurs, the comparator output remains low for more than 30 seconds. The main control chip, based on this signal level, determines it as a genuine fault and activates the wireless communication module. Simultaneously, the temperature sensor continuously collects the pipe wall temperature signal. After the heating stops, the pipe wall temperature gradually decreases to ambient temperature (approximately 0℃~10℃ in outdoor environments), falling below the lower temperature threshold of 40℃. The main control chip packages the device ID, heating outage fault code, and current temperature value together. The wireless communication module automatically selects the optimal communication link based on the current signal strength and sends a message containing the device ID, fault code, and temperature value to the cloud platform.

[0058] After receiving the alarm message, the cloud platform simultaneously displays the fault location and temperature data. Maintenance personnel can remotely view the alarm location and its temperature value through the platform client. If the temperature value is below 40℃, after remotely confirming the alarm as a genuine heating outage fault, a repair order is dispatched.

[0059] In an outdoor environment without mains power, the output voltage of the photovoltaic power supply drops to DC2.8V (below the DC3.0V undervoltage threshold) due to continuous cloudy and rainy days. The power switching circuit of the power supply unit switches to solid-state lithium battery power within 1 millisecond, and the main control chip and working data are not interrupted.

[0060] During four consecutive months of real-world testing on a DN300 pipeline, the equipment experienced five actual heating outages and 23 water hammer disturbances. All actual heating outages correctly triggered alarms, and all water hammer disturbances were correctly masked, resulting in a false alarm rate of 0%. In the dual-power redundant switching test between photovoltaic power and batteries, 10 simulated external power outages occurred, and the switching process did not cause equipment reset or data loss.

[0061] Example 3 according to Figures 1-2 As shown, this embodiment provides a wireless alarm device for a heating outage pipeline based on eddy current electromagnetic induction, applied to a DN100 abandoned branch pipeline in a heating network. This pipeline has been disconnected from the main pipeline valve and is in a disused and idle state, posing a risk of unauthorized opening of the valve to steal hot water, and also a possibility of internal leakage in the valve leading to accidental water flow. The installation location is a narrow valve well with extremely limited space. It includes: Prefabricated induction coil assembly: adopts an elastic spiral binding structure. The induction coil is formed by winding 1000 turns of high-temperature resistant insulated enameled wire with a wire diameter of 0.15mm. The entire coil is sealed inside a waterproof insulating sheath and is secured to the outer wall of the DN100 pipe by wrapping it with anti-corrosion elastic binding tape.

[0062] Signal conditioning circuit board: Same as in Examples 1 and 2, integrating an instrumentation amplifier, a rectifier filter circuit and a comparator.

[0063] Main control chip and wireless communication module: A SoC (System-on-a-Chip) integrated chip is used, which integrates the main control processor, RF transceiver, and power management module into a single chip. This simplifies peripheral circuitry, minimizes the overall size, and allows for installation in narrow valve wells. The main control chip has a built-in anti-shake timing program with a preset duration of 30 seconds. The wireless communication module uses a 4G communication module for second-level reporting of emergency alarms.

[0064] Power supply unit: It adopts a solid-state lithium battery power supply mode with a battery capacity of 10Ah, which meets the long-term standby requirements under the condition of no external power in the narrow valve well.

[0065] Protective housing: Miniaturized housing, suitable for installation in narrow valve wells where DN100 abandoned branch lines are located.

[0066] Tamper monitoring unit: includes vibration sensor, displacement sensor and physical tamper switch.

[0067] The difference between this embodiment and embodiments one and two is that the decision logic direction of the main control chip is reversed.

[0068] Meanwhile, a platinum resistance temperature sensor is used, mounted on the outer wall of the protective housing, maintaining contact with the outer wall of the unused pipe. The temperature sensor is electrically connected to the main control chip, used to collect the temperature signal of the outer wall of the DN100 unused pipe and transmit it to the main control chip. The main control chip internally sets an upper limit of 40℃ for the temperature threshold. In reverse detection mode, a temperature value higher than 40℃ indicates abnormal water flow in the pipe, and a temperature value lower than 40℃ indicates that the pipe is normally dry.

[0069] When the pipeline is normally dry, the induced voltage output by the induction coil is extremely low, and after signal conditioning, the DC voltage signal amplitude is 0.3V. The threshold voltage is set to 0.6V by adjusting the potentiometer. When the pipeline is normally dry, the DC voltage signal amplitude (0.3V) is lower than the threshold voltage (0.6V), and the comparator outputs a low-level signal. Simultaneously, the temperature sensor collects the temperature signal of the idle pipeline's outer wall. When the pipeline is normally dry, the outer wall temperature is close to the ambient temperature (approximately 15℃), lower than the upper temperature threshold of 40℃. The temperature sensor transmits the collected temperature signal to the main control chip, which records the temperature status as "normal (no water)". The main control chip receives the low-level signal and, combined with the temperature status of "normal (no water)," determines that the pipeline status is normal, and the entire unit enters a low-power sleep state.

[0070] When unauthorized individuals open the valve to allow water to flow, water flow is generated in the pipe. The eddy current effect causes the output voltage of the induction coil to rise. After signal conditioning, the DC voltage signal amplitude rises to 1.2V, exceeding the threshold voltage by 0.6V. The comparator output changes from low to high. Simultaneously, the inflow of hot water raises the temperature of the pipe's outer wall to 55℃~65℃. The temperature sensor collects the increased temperature value and transmits it to the main control chip, exceeding the upper temperature threshold of 40℃. The main control chip records the temperature status as "abnormal (water flow)". Upon detecting this transition, the main control chip initiates an anti-jitter timing program. After the high-level signal persists for 30 seconds, the main control chip determines the event as an abnormal water flow (i.e., heat theft) based on the signal level and generates an abnormal water flow alarm message. The main control chip packages the device ID, abnormal water flow fault code, and the current temperature value (the increased temperature value) together. The 4G communication module sends the message containing the device ID, fault code, and temperature value to the cloud platform within one second.

[0071] After parsing the alarm message, the cloud platform marks the fault location on the GIS map with an orange icon. If the temperature value is higher than the upper limit of the temperature threshold of 40℃, the maintenance work order will include supplementary information such as "The pipe outer wall temperature has risen to XX℃, judged as an abnormal water flow event," reminding maintenance personnel to go to the site to verify whether there is any heat theft. If the temperature value in the alarm message is still lower than 40℃, the maintenance work order will include the prompt "Temperature data is abnormal, please verify on-site."

[0072] The equipment operated in standby mode on idle pipelines for three consecutive months without any abnormal water flow events. The equipment remained in a low-power sleep state throughout, with extremely low battery consumption. In two simulated heat theft tests, the equipment correctly triggered the abnormal water flow alarm in both tests. The alarm response times (from valve opening to platform receiving the alarm) were 28 seconds (including 30 seconds of anti-shake confirmation) and 29 seconds, respectively, with 4G communication module upload times of 0.8 seconds and 0.7 seconds, respectively.

[0073] It should be noted that the alarm devices involved in Embodiments 1, 2 and 3 above can be used in conjunction with remote alarm receiving units and cloud-based centralized platform management systems in actual network applications.

[0074] The remote alarm receiving unit, installed at the management station or monitoring center of the heating network, includes a multi-mode receiving module, a control microcontroller, a relay output interface, and an audible and visual alarm. The multi-mode receiving module is compatible with the wireless communication module of the alarm device, receiving wireless alarm signals in LoRa, NB-IoT, and 4G formats. After demodulation and decoding, it extracts the fault code message and transmits it to the control microcontroller. The control microcontroller distinguishes between three types of faults based on the fault code message: heating outage fault, anti-theft / tampering fault, and low battery fault. For a heating outage fault, the control microcontroller outputs a contact signal through the relay output interface to connect to the heating company's PLC system, integrating the heating outage fault information into the central monitoring system, and simultaneously triggering the local audible and visual alarm to issue a heating outage fault alarm. For an anti-theft / tampering fault, the control microcontroller triggers an anti-theft alarm sound and displays a stolen equipment notification on the monitoring interface. For a low battery fault, the control microcontroller displays a list of low-battery devices on the monitoring interface.

[0075] For a cloud-based centralized platform management system, it is deployed on a cloud server and interacts with alarm devices and remote alarm receiving units via the internet. The cloud-based centralized platform management system implements the following functions: equipment file management (entering equipment ID, installation location latitude and longitude coordinates, pipe diameter, and other file information); online status viewing (real-time display of online / offline status of each device through periodic heartbeat messages); GIS fault location (automatically marking fault locations on a GIS map with different colored icons after receiving an alarm signal: red for heating failure, orange for burglar alarms, and yellow for low battery); dismantling / relocation anomaly alerts (real-time alarms are sent to maintenance personnel via SMS and APP after tampering is triggered); and battery power statistics (generating battery power statistics for each device). The system includes: power consumption reports (automatically generating a list of low-power devices when power consumption is below 20%); historical data storage (fully storing alarm events, heartbeat records, and device status changes for at least three heating seasons); operation and maintenance report export (automatically generating daily / weekly / monthly / heating season reports such as fault frequency statistics and online rate statistics, supporting Excel and PDF export); remote online modification of device parameters (maintenance personnel can remotely issue commands to online devices via the backend management interface to reset threshold voltage, reset anti-shake timing preset duration, manually switch wireless communication modes, and adjust sleep / wake cycle, etc.). The cloud-based centralized platform management system provides standard API interfaces, which can be connected to the existing smart heating network dispatching platform of heating companies to achieve seamless integration of heating network monitoring with the company's existing operation and maintenance processes.

[0076] After receiving alarm messages from alarm devices, the cloud-based centralized platform management system parses the device ID, status anomaly code, and temperature value collected by the temperature sensor. The platform compares the temperature value with a preset lower temperature threshold (forward detection mode, for in-use pipelines experiencing heat outages or flow interruptions) or upper temperature threshold (for reverse detection mode, for idle pipelines with abnormal water flow). The alarm interface simultaneously displays the GIS location information of the fault location and the current temperature value of the pipeline's outer wall, providing auxiliary judgment conclusions in text prompts: If the temperature value is below the lower temperature threshold (forward mode) or above the upper temperature threshold (reverse mode), the platform displays "Temperature data matches the level signal, confirming a genuine fault" and automatically dispatches a work order; if the temperature value is at the boundary between the normal and abnormal ranges, the platform displays "Temperature data is abnormal, please verify on-site" and suspends automatic work order dispatch, awaiting remote confirmation from maintenance personnel. Maintenance personnel can remotely view the alarm location and its temperature data through the platform client, assisting in determining the authenticity of the alarm event and reducing unnecessary on-site visits.

[0077] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its framework and scope of application, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wireless alarm device for a heating outage pipeline based on eddy current electromagnetic induction, characterized in that: include: A prefabricated induction coil assembly includes a waterproof insulating sleeve and an induction coil sealed within the waterproof insulating sleeve. The outer wall of the waterproof insulating sleeve is fixedly connected with a fastening member for detachably fastening the waterproof insulating sleeve to the outer wall of a heating pipe. The signal conditioning circuit board integrates an instrumentation amplifier, a rectifier filter circuit, and a comparator. The differential input terminal of the instrumentation amplifier is electrically connected to the output terminal of the induction coil and is used to differentially amplify the induced voltage signal output by the induction coil. The input terminal of the rectifier filter circuit is electrically connected to the output terminal of the instrumentation amplifier and converts the differentially amplified AC induced voltage signal into a DC voltage signal. The comparator has a first input terminal and a second input terminal. The first input terminal is connected to the DC voltage signal, and the second input terminal is connected to a threshold voltage. The comparator compares the amplitude of the DC voltage signal with the threshold voltage and outputs a level signal representing the on / off state of the pipeline based on the comparison result. The main control chip is electrically connected to the output of the comparator and is used to receive the level signal. Then, it determines whether the pipeline has an abnormal state based on the duration of the level signal being continuously lower or higher than the threshold voltage. The wireless communication module is electrically connected to the main control chip and is woken up when the main control chip determines that the pipeline has a heat outage fault, and sends a wireless alarm signal to the cloud-based centralized platform management system. The protective housing has a waterproof interface for the lead wire of the induction coil to pass through, and the signal conditioning circuit board, the main control chip and the wireless communication module are all sealed in the inner cavity of the protective housing.

2. The wireless alarm device for a heating-stopping pipeline based on eddy current electromagnetic induction according to claim 1, characterized in that: The fastening component is a corrosion-resistant elastic strap, which is connected to both ends of the waterproof insulating sheath and is spirally wound and fastened to the outer wall of the heating pipeline.

3. The wireless alarm device for a heating-stopping pipeline based on eddy current electromagnetic induction according to claim 1, characterized in that: The fastening component is a threaded fixing base, which includes two semi-annular clips and a bolt. The two semi-annular clips are engaged and clamped to the outer wall of the heating pipe. The two semi-annular clips are locked together by the bolt. The waterproof insulating sleeve is fixed to the threaded fixing base by clips.

4. The wireless alarm device for a heating-stopping pipeline based on eddy current electromagnetic induction according to claim 1, characterized in that: The induction coil is formed by winding high-temperature resistant insulated enameled wire with a wire diameter of 0.1mm to 0.3mm and the number of turns of the induction coil is 500 to 2000.

5. A wireless alarm device for a heating-stopping pipeline based on eddy current electromagnetic induction according to claim 1, characterized in that: The threshold voltage is set by adjusting the potentiometer.

6. A wireless alarm device for a heating-stopping pipeline based on eddy current electromagnetic induction according to claim 1, characterized in that: The main control chip has a built-in anti-shake timing program. The anti-shake timing program determines the shielding state as abnormal when the duration for which the level signal is continuously lower or higher than the threshold voltage is less than a preset duration.

7. A wireless alarm device for a heating-stopping pipeline based on eddy current electromagnetic induction according to claim 1, characterized in that: The wireless communication module is a three-mode adaptive communication module, which integrates a LoRa communication module, an NB-IoT communication module, and a 4G communication module. The three-mode adaptive communication module automatically selects one of the LoRa communication module, NB-IoT communication module, and 4G communication module to send a wireless alarm signal based on the communication signal strength in the current environment. Multiple alarm devices upload alarm signals to a cloud-based centralized platform management system via their respective wireless communication modules. The cloud-based centralized platform management system includes an equipment filing and management module, a fault location GIS positioning module, and a status statistics module. The equipment filing and management module is used to input the device ID and corresponding installation location information of each alarm device. The fault location GIS positioning module is used to mark the fault location on a GIS map based on the installation location information associated with the device ID after receiving the alarm signal. The status statistics module is used to classify and statistically analyze the abnormal status events reported by each alarm device.

8. A wireless alarm device for a heating-stopping pipeline based on eddy current electromagnetic induction according to claim 1, characterized in that: It also includes a power supply unit, which is disposed in the inner cavity of the protective housing and is electrically connected to the signal conditioning circuit board, the main control chip and the wireless communication module respectively; The power supply unit includes an external power input terminal and a solid-state lithium battery. The DC voltage input range of the external power input terminal is DC3.3V to DC12V. The power supply unit has three power supply modes: External power input terminal independent power supply mode, solid-state lithium battery independent power supply mode, external power input terminal and solid-state lithium battery dual power redundant power supply mode; In the dual-power redundant power supply mode, the power supply unit prioritizes supplying power to the outside via the external power access terminal. When the input voltage of the external power access terminal is lower than the preset undervoltage threshold, the power supply unit seamlessly switches to power supply via a solid-state lithium battery.

9. A wireless alarm device for a heating-stopping pipeline based on eddy current electromagnetic induction as described in claim 8, characterized in that: The power supply unit also includes a voltage regulator chip, which is connected to the external power input terminal and the output terminal of the solid-state lithium battery. The voltage regulator chip stabilizes the output voltage of the power supply unit to DC 3.3V.

10. A wireless alarm device for a heating-stopping pipeline based on eddy current electromagnetic induction according to claim 7, characterized in that: The signal conditioning circuit board, the main control chip, and the wireless communication module are integrated in the inner cavity of the protective housing via surface mount technology. A temperature sensor is provided on the outer wall of the protective housing, and an anti-tamper monitoring unit is also provided in the inner cavity of the protective housing. The temperature sensor and the anti-tamper monitoring unit are electrically connected to the main control chip. When the main control chip determines that the pipeline is in an abnormal state and wakes up the wireless communication module, it sends the temperature signal along with the alarm signal to the cloud-based centralized platform management system. The anti-tamper monitoring unit includes a vibration sensor, a displacement sensor, and a physical anti-tamper switch. The vibration sensor detects the vibration impact on the protective housing, the displacement sensor detects the spatial displacement of the protective housing, and the physical anti-tamper switch is set at the open / closed position of the protective housing. When the main control chip outputs an abnormal level signal from any one of the vibration sensor, displacement sensor, or physical tamper switch, it wakes up the wireless communication module to send an anti-theft alarm signal.

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