Design Method of Portable Underwater Current Sensing Device

Abstract

This invention discloses a design method for a portable underwater current sensing device, comprising the following steps: S1: analyzing the working principle of electricity in water; S2: analyzing the required functions of the portable underwater current sensing device; the required functions of the portable underwater current sensing device include floating function, triggering function, fixing function, unidirectional loop formation function, underwater current detection function, and early warning display function; S3: designing the corresponding structures for the required functions of the portable underwater current sensing device; S4: assembling the portable underwater current sensing device to prepare a portable underwater current sensing device model; S5: conducting feasibility experiments and optimization of the portable underwater current sensing device model. The underwater current sensing device finally obtained by the design method of this invention can detect underwater current, avoiding the risk of electric shock to rescuers entering the water. It is small in size, easy to carry, and has low power consumption.

Description

Technical Field

[0001] This invention relates to the field of current detection technology, and in particular to a design method for a portable underwater current sensing device. Background Technology

[0002] With the development of marine underwater engineering technology, the application scope of underwater electrical systems is becoming increasingly widespread. Currently, in addition to underwater welding and cutting, applications include underwater lighting, power tools, instruments and equipment, underwater television cameras, underwater photography, underwater work chambers, underwater power or control power supplies for subsea oil and gas production facilities, and the supplied current for cathodic protection devices of large structures. All of these involve a common fundamental issue: the safety of underwater electrical systems.

[0003] Human activities are increasingly intertwined with the aquatic environment, leading to a rise in the number of water-related accidents. This presents a more severe challenge to underwater rescue. There is an urgent need to design and invent an underwater current detection device to detect current in water and prevent electric shock injuries in urban water rescue environments.

[0004] Currently, electrical testing equipment on the market mainly checks whether circuits are energized or monitors leakage current at high-voltage circuit interfaces. Based on their testing principles, these devices are not feasible for detecting leakage current in water. The working environment in water is vastly different from air, and the hazards in water are more diverse, making the detection of these hazards particularly important. In today's era of universal electrical connectivity, electrical appliances are present wherever people are; humans and electricity are inextricably linked. During fire rescue operations, after water trucks extinguish fires, indoor flooding often occurs. Firefighters blindly entering such areas for rescue operations are highly susceptible to electric shock. Furthermore, underwater operations such as swimming pool work and disaster relief require extreme caution against electric shock, yet there are currently no devices specifically designed for detecting leakage current in water. Summary of the Invention

[0005] To address the aforementioned problems, this invention aims to provide a design method for a portable underwater current sensing device that can detect current in water, thereby avoiding the risk of electric shock for rescuers entering the water.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A design method for a portable underwater current sensing device includes the following steps.

[0008] S1: Analyze the working principle of electricity in water and the safety of underwater operations;

[0009] S2: Analyze the required functions of a portable underwater current sensing device; the required functions of a portable underwater current sensing device include floating function, triggering function, fixing function, unidirectional loop function, underwater current detection function, and early warning display function.

[0010] S3: Design a structural system that corresponds to the required functions of the portable underwater current sensing device;

[0011] S4: Assemble the portable underwater current sensing device and prepare a model of the portable underwater current sensing device;

[0012] S5: Conduct feasibility experiments and optimize a portable underwater current sensing device model.

[0013] Furthermore, the specific operation of step S3 includes the following steps:

[0014] S301: Design of the housing shape and floating mechanism of a portable underwater current sensing device;

[0015] S302: Design the specific structure of the triggering device, wherein a fixed anchor for fixing and conducting electricity is connected to the triggering device, and the triggering device is used to drive the fixed anchor to fall outside the housing;

[0016] S303: Design of the detection device and circuit for a portable underwater current sensing device;

[0017] S305: Design of an alarm device for a portable underwater current sensing device.

[0018] Furthermore, the portable underwater current sensing device has a streamlined housing shape and is made of a material with a density less than that of water. The housing has a cavity for installing the fixing anchor, triggering device, detection device, and alarm device.

[0019] Furthermore, the triggering device includes a first buoyancy seesaw and a container box. A first suspending bubble is connected to the bottom of one end of the first buoyancy seesaw, and the first suspending bubble penetrates the shell. A plug-in flexible plate is connected to the top surface of the other end of the first buoyancy seesaw. The end of the plug-in flexible plate away from the first buoyancy seesaw is movably connected to the container box, and the plug-in flexible plate divides the container box into an upper chamber and a lower chamber. An air bladder is connected to the lower chamber through a connecting pipe. The fixed anchor is located inside the air bladder. A needle is also provided in the shell at a position corresponding to the air bladder. A through hole is opened at the bottom of the shell for the fixed anchor to pass through.

[0020] Furthermore, the triggering device includes a second buoyancy seesaw and a baffle. The bottom surface of the housing has a first through hole that matches the baffle. One end of the baffle is hinged to the edge of the first through hole. The fixed anchor is located inside the housing at a position corresponding to the first through hole. A second suspending bubble is connected to the bottom of one end of the second buoyancy seesaw, and the second suspending bubble penetrates the housing. The other end of the second buoyancy seesaw is connected to a first pull rope and a second pull rope. A first fixed pulley is installed inside the housing. The free end of the first pull rope after passing over the first fixed pulley is connected to a limit ring. The free end of the second pull rope is connected to a pin, and the pin is movably inserted into the baffle.

[0021] Furthermore, the triggering device includes a float plate, and the bottom of the housing has a second through hole that matches the float plate; the top of the housing is connected to a connecting part, the major axis diameter of the connecting part is smaller than the major axis diameter of the housing, the top of the fixed anchor is engaged in the connecting part, the bottom of the fixed anchor is located inside the housing, and a plurality of locking pins are hinged to the inner sidewall of the housing, one end of the locking pin contacts the bottom of the fixed anchor, the other end of the locking pin contacts the top surface of the float plate, and the center of the float plate has a third through hole for the fixed anchor to pass through.

[0022] Furthermore, the fixed anchor is a solid structure, and the fixed anchor includes a tie rod, the bottom of which is fixed with an arc-shaped gripping rod, both ends of which are gripping tips.

[0023] Furthermore, the detection device includes a fixed anchor, which is connected to a resistor and the alarm device via a wire. The resistor is located inside the housing, and the detection device is mounted on the side wall of the housing.

[0024] Furthermore, the alarm device includes two neon lamps and a buzzer.

[0025] The beneficial effects of this invention are:

[0026] 1. Using the design method in this invention, a complete portable underwater current sensing device can be designed. This device can float on the water surface and drive the fixed anchor to detach from the shell and sink to the bottom through a trigger component. Since the fixed anchor is made of metal, it is conductive, thus forming a one-way circuit with the conductive rope, resistor, and alarm light. When there is a leakage in the water, current will flow through the one-way circuit formed by the fixed anchor, conductive rope, resistor, and alarm light, relying on the leakage power source. This will cause the alarm light to light up, thus alerting the user to detect the leakage in the water and avoiding the risk of electric shock for rescuers. It is applicable to water bodies at a distance.

[0027] 2. The fixed anchor in this invention can not only serve as a conductive part in the detection component, but also grab debris in the water as a leverage point to fix the position of the entire device and resist the influence of external forces such as wind and current.

[0028] 3. In the process of designing the portable underwater current sensing device, three different triggering devices were tried. All three triggering devices can drive the fixed anchor to detach from the shell. However, it was found in the design process that using a buoyancy seesaw structure as the triggering device results in lower stability of the entire underwater current sensing device compared to using a buoyancy plate as the triggering device. This also provides a better direction for improvement in practical applications.

[0029] 4. The shell of this invention adopts a streamlined structure, which reduces wind resistance and increases throwing distance while taking into account the aesthetic design concept, making the appearance more beautiful; the internal mounting cavity provides design space for other structures required by the device, and the detection device is small in size and easy to carry.

[0030] 5. The underwater current sensing device involved in this invention does not require an additional power source to power it, has low power consumption, long battery life, and can reduce the weight of the device itself. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating the design method of the portable underwater current sensing device in this invention.

[0032] Figure 2 This is a diagram of pure water ionization.

[0033] Figure 3 This diagram illustrates the formation of electric currents in water.

[0034] Figure 4 This is a closed-loop diagram of the current.

[0035] Figure 5 This is a unidirectional loop diagram of current in water.

[0036] Figure 6 The flowchart shows the device operation process corresponding to the functional design of the portable underwater current sensing device in this invention.

[0037] Figure 7 This is a schematic diagram of the streamlined appearance.

[0038] Figure 8 This is a schematic diagram of the buoyancy seesaw principle in this invention.

[0039] Figure 9 This is a schematic diagram of the triggering device structure in Embodiment 1 of the present invention.

[0040] Figure 10 This is a schematic diagram of the fixed anchor structure in Embodiment 1 of the present invention.

[0041] Figure 11 This is a schematic diagram of a single-phase closed loop in Embodiment 1 of the present invention.

[0042] Figure 12 This is a schematic diagram of the triggering device structure in Embodiment 2 of the present invention.

[0043] Figure 13 This is a schematic diagram of the triggering device structure in Embodiment 3 of the present invention.

[0044] Figure 14 This is the first circuit connection diagram used in the experimental verification of this invention.

[0045] Figure 15 This diagram shows the fuse burning out during the first circuit connection test for the present invention.

[0046] Figure 16 This is the second circuit connection diagram used in the experimental verification of this invention.

[0047] Figure 17 This is a schematic diagram of the experimental principle for the feasibility test of the device of the present invention.

[0048] Wherein: 100-shell, 1001-cavity, 200-fixed anchor, 2001-pull rod, 2002-grabbing rod, 2003-grabbing tip, 2004-lifting ring, 300-resistor, 400-neon lamp, 500-buzzer, 1-first buoyancy seesaw, 2-first suspension bubble, 3-plug-in flexible plate, 4-container box, 401-upper chamber, 402-lower chamber, 5-connecting tube, 6-airbag, 7-needle, 8-second buoyancy seesaw, 9-baffle, 10-first through hole, 11-second suspension bubble, 12-first pull rope, 13-second pull rope, 14-first fixed pulley, 15-limiting ring, 16-pin, 17-float plate, 18-second through hole, 19-connecting part, 20-clamping post, 21-third through hole. Detailed Implementation

[0049] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0050] Example 1:

[0051] A design method for a portable underwater current sensing device, as shown in the appendix. Figure 1 As shown, it includes the following steps:

[0052] S1: Analyze the working principle of electricity in water and the safety of underwater operations;

[0053] Specifically, through precise experiments, water has been shown to be a very weak electrolyte, capable of slight ionization to produce hydrogen gas and hydrogen ions. Its ionization equation can be expressed as: As attached Figure 2 As shown.

[0054] Water conducts electricity because of the directional movement of ions in aqueous solutions. (See attached image) Figure 3 As shown in (a), before energizing, although ions in the aqueous solution are constantly moving, their disordered movement causes the "tiny currents" generated by individual ions to superimpose and cancel each other out, resulting in no current flowing through the solution macroscopically. If an external electric field is applied, as shown in the attached diagram... Figure 3 As shown in (b), when electricity is applied, ions in the solution will move in a specific direction under the influence of the electric field, forming an electric current, which is called conduction.

[0055] Depending on water quality and power supply voltage, the distance at which voltage breaks down through water during a leakage current varies, thus affecting the area of ​​potential electric shock hazard in water. Experiments have shown that 220V voltage can conduct over 100 meters in river water, while the effective kill range is approximately 10 meters. There is no standard definition for the conduction distance of current in water; the equivalent resistance varies depending on the impurities present in the water, and several meters may be considered a safe distance.

[0056] Factors affecting the safety range include: the magnitude of the leakage voltage, the depth of the wire submerged in water, the turbidity of the water, and the size of the water surface.

[0057] The higher the leakage voltage, the farther the safe range; the deeper the wire is submerged in water, the greater the safe range above the water surface and the smaller the safe range underwater; the turbidity of water mainly affects the conductivity of water by influencing the concentration of ionized particles in the water, and the greater the concentration of ionized particles in the water, the farther the safe range.

[0058] The mechanism of electrical conductivity in water is as follows: A standard closed circuit consists of five elements: power source, load, wiring, control device, and protection device, as shown in the appendix. Figure 4 As shown, in the event of a leakage current or electric shock, the protective device will be activated to disconnect the power supply, thus preventing electric shock injury. Circuits and appliances in daily life all have similar electrical protection mechanisms to ensure the safety of users. However, if power lines are flooded, water, being a good conductor of electricity and possessing excellent fluidity and propagation properties, can indirectly cause the protective devices to fail.

[0059] The underwater circuit is a one-way loop without control or protection devices; the current flows through water to the earth and is neutralized and absorbed by the earth. (See attached image) Figure 5As shown, the electricity in the water continuously discharges and is conducted into the ground, creating an electric shock zone in a certain area around the source. When a person comes into contact with the water, they indirectly come into contact with the electrical circuit, facing the risk of electric shock or even death.

[0060] Water, a medium around a leaking electrical device that has been broken down by voltage, can be considered a conductor. A person, being a good conductor of electricity, will experience current flow if they enter this environment. A current of 50mA passing through the human body can cause cardiac arrest and respiratory paralysis, potentially leading to death. Since it's impossible to visually determine whether water is electrified, this can create a false sense of security, leading to electric shock upon contact.

[0061] Studies have shown that when an electric current passes through the human body (16 mA for men and 10 mA for women), the body cannot extricate itself from the charged conductor, causing abnormal pain and unbearable suffering. If this continues for too long, it may lead to coma, suffocation, or even death. A current of 30 mA is extremely dangerous. When the current exceeds 30 mA in the body, it can cause cardiac arrhythmia, brief dizziness, increased blood pressure, severe convulsions, and even potentially fatal cardiac arrhythmia. 50 mA is the lower limit of ventricular fibrillation current (or lethal current), which is the minimum current that can cause myocardial fiber fibrillation in the human body. A 50 mA current remaining in the body for just one second can cause ventricular fibrillation and death.

[0062] The analysis of the working principle of electricity in water and the safety of underwater operations can provide a theoretical basis for the functional requirements and specific design direction of underwater current sensing devices.

[0063] Furthermore, S2: Analyze the required functions of a portable underwater current sensing device;

[0064] Specifically, the requirements analysis methods employed in this invention mainly include: a survey / interview-based requirements analysis method—interviewing firefighters to understand their intrinsic needs; a scenario-based requirements analysis method—analyzing on-site factors to ensure the device's functions adapt to environmental requirements; a feature-based requirements analysis method—for water environments; and an object-oriented requirements acquisition and analysis method—based on the device's operation process, as shown in the appendix. Figure 6 As shown, the detection device is thrown to the predetermined detection position by the operator. The device floats on the water surface and forms a one-way circuit in the water. At the same time, the device contacts the water surface and triggers the excitation device to strengthen the one-way circuit and fix the device. The operator judges whether there is electricity in the water by observing whether the alarm is triggered, so as to ensure that there is no risk of electric shock in the water area to be tested.

[0065] Combining diverse demand analysis methods, and considering the lack of feasibility of underwater current measurement devices in the existing market, this device must be designed to meet practical considerations and application requirements. Based on design principles, and taking into account on-site operating procedures, fire safety requirements, and actual needs, the underwater current detection device needs to possess the following functions:

[0066] (1) Floating function on water

[0067] Due to its suitability for aquatic environments, the device needs to float on the water surface to eliminate the influence of water on its alarm function. If the device does not have a floating function, it will sink into the water. This would cause the device to lose its location within the field of view, resulting in a lack of intuitive presentation and monitoring of its operational status. Furthermore, the characteristics of the aquatic environment itself would interfere with the device's alarm function and hinder its recovery. Therefore, a floating function is an essential feature of this device.

[0068] (2) Triggering function

[0069] The activation function is achieved through an activation device. Based on the device's workflow and characteristics, an activation device is designed. When certain external environmental conditions are met, the activation device is triggered, and certain measures are taken to achieve the desired functions of the device. The existence of the activation function allows for the internalization of some structural aspects of the device, making its portability and appearance more consistent with design principles and actual site requirements.

[0070] (3) Fixed and forming a unidirectional loop function

[0071] Due to the fluidity of water, the device must possess robust fixation capabilities to ensure accurate detection positioning. This fixation requires the ability to withstand certain water wave impacts, ensuring the device hovers over the water area being measured, thus guaranteeing accurate measurement results. A unidirectional loop is a prerequisite for current detection; water discharge forms a unidirectional loop, with the current flowing through water to the ground where it is neutralized and absorbed. The device constructs a higher-priority unidirectional loop to capture the current in the water. Both of these functions are achieved by suspending a weight.

[0072] (4) Underwater current detection function

[0073] The underwater detection function is the core function of this device. The principle of designing a leakage current detection device is to detect the current in the water. This requires the device to have a good sensing function for the current in the water, be able to sense the current in the water, and reflect a clear alarm signal through a reasonable structural design so that the user can receive it, thereby avoiding blindly entering the water and suffering electric shock injury.

[0074] (5) Early warning display function

[0075] Considering the various factors affecting the scene, this device adopts a visual alarm, which is unaffected by sound or signal interference, and is simple, direct, and reliable. Rescue scenes may be noisy or even disruptive, and using a sound alarm function could result in users being unable to hear it or mishearing it. Using signal devices such as Bluetooth would be susceptible to signal interference, and users would need to carry signal receivers, violating the principle of simplicity in fire equipment design and increasing costs. Therefore, this device uses a visual alarm function.

[0076] Furthermore, S3: To design a corresponding structural structure for the required functions of the portable underwater current sensing device;

[0077] Specifically, S301: Design the shape and floating method of the housing 100 of the portable underwater current sensing device;

[0078] More specifically, considering the functional requirements of launching, and based on existing technology, a choice between square and circular device shapes is proposed. A comparative analysis of the general appearances of the square and circular shapes is conducted, taking into account the actual conditions during launch and flight. The comparative analysis of the performance of the square and circular shapes is shown in Table 1 below.

[0079] Table 1 Comparative Analysis of the Performance of Square and Circular Devices

[0080]

[0081] The area of ​​the square is S = (2a) 2 =4a 2

[0082] The area of ​​the circle is S = πa 2

[0083] It is evident that for devices of the same size, a circular design results in lower wind resistance, better aesthetics, and higher overall performance. Furthermore, considering the practical needs of a three-dimensional overall design, the circular shape is optimized and combined to create a streamlined, three-dimensional design, as shown in the attached image. Figure 7 As shown.

[0084] The streamlined exterior design reduces wind resistance and increases throwing distance while also adhering to aesthetic design principles, making the device more visually appealing. Furthermore, the hollow interior structure provides design space for other structural elements required by the device.

[0085] The streamlined shell 1 in this invention operates on a principle similar to that of a flying saucer: the top surface of the flying saucer is convex. During high-speed rotation, due to hydrodynamics, the air pressure above the flying saucer is lower than the air pressure below it, thus creating an upward thrust that suspends the flying saucer in mid-air, allowing it to fly farther.

[0086] Streamlined shapes are typically rounded at the beginning and tapered towards the end, with a smooth surface, somewhat resembling a small water droplet. They are generally smooth and regular, without obvious ripples or sharp edges. In such devices, the liquid (in gaseous form) flows over the surface of the streamlined object, usually in a laminar or turbulent flow. From a fluid dynamics perspective, within the same force-bearing area, the pressure on the target surface is minimized; therefore, streamlined objects experience minimal resistance as they move through the liquid.

[0087] There are two ways to make an object float on water: ① Wood has a lower density than water. ② Toothpaste rolled up sinks in water, but a "hollow" toothpaste tube can float, indicating that "hollowness" can adjust the relationship between buoyancy and gravity. "Hollowness" increases volume, increasing buoyancy, allowing the object to float on the liquid surface. Following the suspension methods of wood and "hollow" toothpaste, this device can use two floating methods: using a material with a density less than water and using a hollow airbag to increase buoyancy. Considering the safety and reliability of fire rescue, this invention adopts two floating methods: the housing 100 of the portable underwater current sensing device has a streamlined shape, and the housing 100 is made of a material with a density less than water. The housing 100 has a cavity 1001 for installing the fixed anchor 200, triggering device, detection device, and alarm device.

[0088] In this invention, when selecting the material for the shell 100, both foam and plastic have good buoyancy. However, given that foam has too low strength, plastic, which has lower density, higher strength, and is more economical and practical, was chosen for the buoyancy design. A comparative analysis of various common plastics is shown in Table 2 below.

[0089] Table 2 Comparison of Common Plastics

[0090]

[0091] Based on the analysis of the fire rescue site environment, the overall ambient temperature is relatively high. Plastic materials such as PET, HDPE, PVC, and LDPE generally have poor heat resistance. Therefore, PP (polypropylene) plastic was selected as the floating design material for this device. Although polyethylene plastic has poor impact performance and aging performance at low temperatures, this can be solved by modifying it or adding antioxidants.

[0092] S302: Design the specific structure of the triggering device, wherein a fixing anchor 200 for fixing and conducting electricity is connected to the triggering device, and the triggering device is used to drive the fixing anchor 200 to fall outside the housing 100;

[0093] More specifically, based on the device's workflow and characteristics, an activation device is designed. When the external environment reaches a certain condition, the activation device is triggered, and certain measures are taken to achieve some functions that the device wants to perform. The activation function that this design aims to achieve is to cause a suspended object to fall from the device into the water. Based on the characteristics of the water environment, the device is to be triggered when it comes into contact with the water surface. The design can utilize the properties of water, and three concepts are mentioned in the design: First, using a water-soluble material to seal the weight drop switch; second, using a water-absorbing material to connect the drop switch, so that when the water-absorbing material reaches a certain weight, it triggers the weight to fall. The performance comparison of the two materials in this design is shown in Table 3 below. The third is called a "buoyancy seesaw," which uses the principle of a seesaw. A suspended air bubble is installed at one end. When it falls into the water, the bubble floats, triggering the switch and causing the weight to fall. A schematic diagram is attached. Figure 8 As shown.

[0094] Table 3 Performance Analysis of Water-Soluble and Water-Absorbent Materials

[0095]

[0096] Borrowing the principle of foam fire extinguishers, when aluminum sulfate and sodium bicarbonate solutions are mixed together, a large amount of carbon dioxide gas is produced.

[0097] Al2(SO4)3+6NaHCO3=3Na2SO4+2Al(OH)3↓+6CO2↑

[0098] right Figure 8 The seesaw structure in the original design was improved, and the triggering device in this embodiment was designed.

[0099] The triggering device is as follows: Figure 9 As shown, the device includes a first buoyancy seesaw 1 and a container 4. A first suspension bubble 2 is connected to the bottom of one end of the first buoyancy seesaw 1, and the first suspension bubble 2 penetrates the shell 100. A plug-in flexible plate 3 is connected to the top surface of the other end of the first buoyancy seesaw 1. The end of the plug-in flexible plate 3 away from the first buoyancy seesaw 1 is movably connected to the container 4, and the plug-in flexible plate 3 divides the container 4 into an upper chamber 401 and a lower chamber 402. The upper chamber 401 contains sodium bicarbonate solution, and the lower chamber 402 contains molybdenum sulfate. An air bladder 6 is connected to the lower chamber 402 through a connecting pipe 5. A fixed anchor 200 is located inside the air bladder 6. A needle 7 is also provided in the shell 100 at a position corresponding to the air bladder 6. A through hole is opened at the bottom of the shell 200 for the fixed anchor 200 to pass through.

[0100] When the device comes into contact with the water surface, the first suspended bubble 2 floats upward due to buoyancy. The other end of the first buoyancy seesaw 1 moves downward accordingly, causing the plug-in flexible plate 3 to be partially pulled out. This causes the sodium bicarbonate solution in the upper chamber 401 to flow down and react with the aluminum carbonate in the lower chamber 402, rapidly generating a large amount of carbon dioxide gas. This gas inflates the airbag 6 through the connecting pipe 5. When the airbag 6 expands to a certain volume, the needle tip of the contact needle 7 is punctured, and the fixed anchor 200 stored inside falls into the water.

[0101] The structure of the fixed anchor 200 is shown in the attached figure. Figure 10 As shown, the device includes a pull rod 2001, with an arc-shaped gripping rod 2002 fixed to its bottom. Both ends of the gripping rod 2002 are gripping tips 2003, and a lifting ring 2004 is fixed to the top of the pull rod 2001. The anchor 200 is a solid structure. Its rough bottom enhances friction with the seabed, and it also provides gripping capability. The solid design strengthens the anchor's own weight and reduces buoyancy. By utilizing the anchor's gripping force underwater, the pull rod 2001's drag force underwater, and the pull rod 2001's own weight, the device resists the influence of external forces such as wind and current, fixing it in its underwater position and achieving its anchoring function.

[0102] The fixed anchor 200 is mainly made of iron, aluminum alloy, and copper. The fixed anchor 200 is primarily made of iron, which has good ductility, electrical and thermal conductivity, and high hardness and density, making it one of the most commonly used materials in industry. Aluminum alloy is electroplated onto the surface of the fixed anchor 200 to prevent rust, and copper penetrates the fixed anchor 200 from the inside to further enhance its conductivity.

[0103] S303: Design of the detection device and circuit for a portable underwater current sensing device;

[0104] Specifically, leakage current detection devices can employ two types of detection designs: one is where the device itself has a built-in power supply, forming a closed loop. The current in the water is detected through a current sensing element; the other utilizes the existing current in the water to guide and trigger the alarm device, without requiring an internal power supply. A comparative analysis of the two detection design types is shown in Table 4 below.

[0105] Table 4 Comparison of the two detection types

[0106]

[0107] Comparative analysis shows that the unidirectional loop design requires no power supply, has lower structural complexity, higher safety, and relatively lower cost. Its overall performance far surpasses that of the closed-loop design. Therefore, the unidirectional loop design was chosen for detecting current in water.

[0108] The design principle of this detection device is as follows: it detects the current field in the water, and the current is connected to the ground to form a one-way loop. The detection device includes a fixed anchor 200, which is connected to a resistor 300 and an alarm device via a wire. The resistor 300 is located inside the housing 100, and the alarm device is installed on the side wall of the housing 100.

[0109] The fixed anchor 200 in this invention is similar to a load segment in a circuit. It uses a leakage current source as its power source, water as its conductor, and the ground as its terminal to form a unidirectional loop for detecting current in the water. When current flows through it, an alarm device is triggered, allowing the user to detect the leakage current in the water.

[0110] The detection device is thrown to the predetermined detection position by the operator. The device floats on the water surface and forms a one-way circuit in the water. At the same time, the device contacts the water surface and triggers the excitation device, which strengthens the one-way circuit and fixes the device. The operator can determine whether there is electricity in the water by observing whether an alarm is triggered.

[0111] S305: Design of an alarm device for a portable underwater current sensing device.

[0112] Common alarm methods include: audible alarms, visual alarms, and audible-visual alarms. Given the noisy working environment and potentially low current supply of this device, audible and audible-visual alarms are not suitable. Therefore, this device uses a visual alarm. This device uses neon lamps, a primary power indicator signal source. Neon lamps are characterized by high voltage, low current, high temperature resistance, small size, light weight, good color rendering, uniform light emission, and long lifespan. Neon lamps are cold cathode glow discharge devices that can penetrate the atmosphere, producing vibrant and varied colors. Their luminous effect is much higher than that of ordinary incandescent lamps, and their linear structure is highly expressive, allowing them to be bent into any geometric shape to meet design requirements.

[0113] The circuit principle in this invention is shown in the appendix. Figure 11As shown. The alarm device includes two neon lamps 400 and a buzzer 500. When the water is electrified, the current flows through one end of the device in the water and then through three branches inside the device. Two of these branches each contain a neon lamp 400. The cold cathode lamp tube contains an appropriate amount of mercury and inert gas. The inner wall of the tube is coated with phosphor, and there is an electrode at each end. When a high voltage is applied to both ends of the tube, the electrodes begin to discharge without heating. The mercury is activated by collisions between electrons or atoms of the inert gas, emitting ultraviolet light at 253.7 nm. The ultraviolet light excites the phosphor coated on the inner wall of the tube to produce visible light; different colors of light are emitted due to the different composition of the fluorescent material. Another branch passes through the AC buzzer 500, which oscillates after passing through a multivibrator, outputting a continuous audio signal. An impedance matching circuit drives a piezoelectric buzzer to produce sound, achieving an audible warning effect. The currents from the three branches converge and flow out from the grounded end, forming a closed loop. The 400 neon lamp serves as a visual alarm, while the 500 buzzer serves as an audible alarm.

[0114] Most alarm lights currently in use are LED lights. LED (Light Emitting Diode) is a solid-state semiconductor device that converts electrical energy into visible light. Another common type used is neon light, often used as an indicator. Neon is an inert gas that generally does not react with other substances. Neon emits an orange glow and is widely used in urban neon lights. A comparison of neon lights and LED lights is shown in Table 5 below.

[0115] Table 5 Comparison and Analysis of Neon Lamps and LED Lamps

[0116]

[0117] Due to the high-temperature environment at fire scenes and the susceptibility of LED lights to damage in high-temperature environments, neon lamps commonly have ignition voltages of 76V, 60V, and 48V. To ensure the accuracy of the device, a neon lamp with an ignition voltage of 56-80V is selected as the alarm lamp for this invention; that is, the alarm device in this application uses a... Figure 11 The neon lamp in the middle is 400.

[0118] S4: Assemble the object 100, fixed anchor 200, resistor 00, neon lamp 400 and triggering device of the portable underwater current sensing device to prepare a portable underwater current sensing device model;

[0119] S5: Conduct feasibility experiments and optimize a portable underwater current sensing device model.

[0120] Specifically, the feasibility test can be conducted indoors by filling a basin with water and electrifying it. The feasibility test includes testing whether the device can detect leakage current, the effect of leakage voltage on the brightness of the neon lamp, and the effect of leakage distance on the brightness of the neon lamp.

[0121] Example 2:

[0122] The only difference between Embodiment 2 and Embodiment 1 is that the triggering device in this embodiment is as shown in the attached diagram. Figure 12 As shown, the housing 100 includes a second buoyancy seesaw 8 and a baffle 9. The bottom surface of the housing 100 has a first through hole 10 that matches the baffle 9. One end of the baffle 9 is hinged to the edge of the first through hole 10. The fixed anchor 200 is located inside the housing 100 at a position corresponding to the first through hole 10. A second suspension bubble 11 is connected to the bottom of one end of the second buoyancy seesaw 8. The second suspension bubble 11 penetrates the housing 100. The other end of the second buoyancy seesaw 8 is connected to a first pull rope 12 and a second pull rope 13. A first fixed pulley 14 is installed inside the housing 100. The free end of the first pull rope 12 after passing over the first fixed pulley 14 is connected to a limit ring 15. The free end of the second pull rope 13 is connected to a pin 16. The pin 16 is movably inserted into the baffle 9.

[0123] When the device comes into contact with the water surface, the second suspended bubble 11 floats upward due to buoyancy. The other end of the second buoyancy seesaw 8 moves downward accordingly, causing the first pull rope 12 to first pull out the limiting ring 15, and then drive the pin 16 to be pulled out from the baffle 9. The baffle 9 rotates, opening the first through hole 10, and the fixed anchor 200 falls into the water through the first through hole 10.

[0124] Example 3:

[0125] During the manufacturing process, it was found that the triggering devices in Embodiments 1 and 2 were prone to shaking, and their stability needed to be improved. Therefore, this embodiment further improves the triggering device, as shown in the attached figure. Figure 13 As shown, the triggering device includes a float plate 17, and a second through hole 18 matching the float plate 17 is provided at the bottom of the housing 100; a connecting part 19 is provided at the top of the housing 100, the major axis diameter of the connecting part 19 is smaller than the major axis diameter of the housing 100, the top of the fixed anchor 200 is engaged in the connecting part 19, the bottom of the fixed anchor 200 is located inside the housing 100, a plurality of locking pins 20 are hinged to the inner sidewall of the housing 100, one end of the locking pin 20 contacts the bottom of the fixed anchor 200, the other end of the locking pin 20 contacts the top surface of the float plate 17, and a third through hole 21 for the fixed anchor 200 to pass through is provided at the center of the float plate 17.

[0126] When the device contacts the water surface, the float 17, under the action of upward buoyancy, pushes one end of the locking pin 20 upward. The locking pin 20 rotates around the hinge point, thereby engaging the limiting action on the fixed anchor 200. Under the action of gravity, the fixed anchor 200 falls into the water through the third through hole 21.

[0127] Experimental verification:

[0128] Experimental scenario setup:

[0129] Aquatic environment – ​​plastic basin filled with water

[0130] Leakage current at different voltage levels – 220V AC power supply connected to a 0-300V AC transformer.

[0131] Experimental circuit connection:

[0132] The circuit connection for the first experiment is shown in the attached figure. Figure 14 As shown in the attached diagram. During the initial connection, considering the high resistance of water, an iron plate was connected to the bottom of the water to enhance conductivity. This resulted in insufficient circuit load, causing the transformer fuse to blow. Figure 15 As shown.

[0133] The circuit connection for the second experiment is shown in the attached figure. Figure 16 As shown, after replacing the fuse with a new one, the experiment was continued. Lessons learned from the previous experiment were fully absorbed, the connecting metal piece was removed, and sufficient load conditions were ensured. The circuit connection was successful.

[0134] (1) Feasibility test of the device:

[0135] The equipment includes a plastic basin filled with water, a simple electrical testing device (the neon lamp's ignition voltage is 56-80V), a 0-300V AC adjustable transformer, a 220V AC power supply, two metal plates, a switch, and several wires. A schematic diagram of the device is attached. Figure 17 As shown.

[0136] The experimental steps include:

[0137] ① Connect the two ends of the plastic bucket containing water to a 220V AC voltage;

[0138] ② 0-300V AC adjustable transformer modulates to 220V;

[0139] ③ Throw the simple electrical measuring device of this design onto the water surface, observe whether the neon lamp lights up and record the result;

[0140] ④ Disconnect the switch and remove the simple electrical measuring device designed in this way;

[0141] ⑤ Repeat steps ①-④ 100 times with different operators.

[0142] Some experimental data are shown in Table 6 below.

[0143] Table 6. Feasibility test data of the device

[0144]

[0145] (Continued from Table 6)

[0146]

[0147] Statistics show that in 4 out of 100 experiments, the neon lamp failed to light up. The reason was that the throwing position was too far and the ignition voltage of the neon lamp was not reached. The reliability was calculated using the following formula:

[0148]

[0149] In the formula, P represents the reliability.

[0150] n – The number of experiments in which the neon lamp did not light up.

[0151] Substituting the data, we get:

[0152] P=(100-4)÷100×100%=96%

[0153] Its reliability was calculated to be 96%, which meets the design reliability standard. Therefore, the designed device is reliable, and the device feasibility test has been passed.

[0154] (2) Experiment on the effect of leakage voltage on the brightness of neon lamp

[0155] The experimental equipment, experimental principles, and apparatus feasibility experiments are the same.

[0156] The experimental procedure includes the following steps:

[0157] ① Connect the two ends of the plastic bucket containing water to a 220V AC voltage.

[0158] ② Modulate the 0-300V AC adjustable transformer to 0V.

[0159] ③ Throw the simple electrical measuring device of this design onto the water surface;

[0160] ④ Gradually adjust the transformer from 0V to 180V, while observing the change in the brightness of the neon lamp and recording the data.

[0161] Based on brightness comparison, brightness is divided into four levels: strong brightness, bright, relatively bright, and dim. These brightness levels are determined through experimental comparison and are not equivalent to any other brightness level. The figures are shown in Table 7 below.

[0162] Table 7. Experimental data on the effect of leakage voltage on neon lamp brightness.

[0163]

[0164] (Continued from Table 7)

[0165]

[0166] (Continued from Table 7)

[0167]

[0168] Under the simulated environmental conditions of this experiment, the device can detect a minimum AC voltage of 111V applied to both ends of the water. Within the voltage range of 111V-120V, the neon lamp brightness level is dim; within the voltage range of 121V-138V, the neon lamp brightness level is relatively bright; within the voltage range of 139V-169V, the neon lamp brightness level is bright; and within the voltage range of 170V-180V, the neon lamp brightness level is very bright.

[0169] Experimental conclusion: When the distance from the leakage point remains constant, the relationship between the leakage voltage and the brightness of the neon lamp is as follows: the larger the leakage voltage, the brighter the neon lamp; the smaller the leakage voltage, the lower the brightness of the neon lamp.

[0170] (3) Experiment on the effect of the distance of the leakage point on the brightness of the neon lamp

[0171] The experimental equipment and schematic diagram are the same as those used in the device feasibility test.

[0172] The experimental procedure includes the following steps:

[0173] ① Connect 220V AC voltage to both ends of the wet plastic container;

[0174] ② 0-300V AC adjustable transformer modulates to 180V;

[0175] ③ Throw the simple electrical measuring device of this design onto the water surface;

[0176] ④ Slowly approach the leakage point from a distance, while observing the change in the brightness of the neon lamp and recording the data.

[0177] Based on brightness comparison, brightness is divided into four levels: strong, bright, moderately bright, and dim. These brightness levels are determined through experimental comparison and are not equivalent to any other brightness level. Experimental data are detailed in Table 8 below.

[0178] Table 8. Experimental data on the effect of the distance of the leakage point on the brightness of the neon lamp.

[0179]

[0180] As shown in Table 8, when the leakage voltage remains constant, the brightness of the device changes significantly as it moves closer to or further away from the leakage point. The closer to the leakage point, the brighter the neon lamp; the farther away, the dimmer the neon lamp. This change can be used to determine the direction of the leakage point and take further action.

[0181] 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 invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method of designing a portable underwater electric current sensing device, characterized in that, It comprises the following steps, S1: analyze the principle of the effect of electricity in water and the safety of water operation; S2: analyze the functions required by the portable underwater electric current sensing device; the functions required by the portable underwater electric current sensing device include water floating function, triggering function, fixing function, one-way loop function, underwater electric current detection function and early warning display function; S3: the required functions of the portable underwater electric current sensing device are designed correspondingly; S4: the portable underwater electric current sensing device is assembled to prepare the portable underwater electric current sensing device model; S5: the feasibility experiment and optimization of the portable underwater electric current sensing device model are carried out; The shell (100) of the portable underwater electric current sensing device adopts streamline shape, and the shell (100) adopts a material with density less than water, and the shell (100) is provided with a cavity (1001) for mounting and fixing an anchor (200), a triggering device, a detection device and an alarm device; The triggering device comprises a floating plate (17), and the bottom of the shell (100) is provided with a second through hole (18) matched with the floating plate (17); the top of the shell (100) is provided with a connecting portion (19) in communication, the long axis diameter of the connecting portion (19) is smaller than that of the shell (100), the top of the fixed anchor (200) is clamped in the connecting portion (19), the bottom of the fixed anchor (200) is located in the shell (100), a plurality of clamping columns (20) are hingedly connected to the inner side wall of the shell (100), one end of the clamping column (20) is in contact with the bottom of the fixed anchor (200), and the other end of the clamping column (20) is in contact with the top surface of the floating plate (17); the center of the floating plate (17) is provided with a third through hole (21) for the fixed anchor (200) to pass through; The fixed anchor (200) is a solid structure, and the fixed anchor (200) comprises a pull rod (2001), and the bottom of the pull rod (2001) is fixedly provided with an arc-shaped grabbing rod (2002), and the two ends of the grabbing rod (2002) are grabbing tips (2003); The detection device comprises a fixed anchor (200), the fixed anchor (200) is connected with a resistor (300) and the alarm device through a lead wire, the resistor (300) is located in the shell (100), and the alarm device is installed on the side wall of the shell (100).

2. The method of designing a portable underwater electric current sensing device according to claim 1, wherein: The specific operation of step S3 comprises the following steps, S301: design the shell shape and floating mode of the portable underwater electric current sensing device; S302: design the specific structure of the triggering device, the triggering device is connected with a fixed anchor for fixing and conducting, and the triggering device is used for driving the fixed anchor to fall out of the shell; S303: design the detection device and circuit of the portable underwater electric current sensing device; S305: design the alarm device of the portable underwater electric current sensing device.

3. The method of designing a portable underwater electric current sensing device according to claim 1, wherein: The alarm device comprises two neon lamps (400) and a buzzer (500).

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