Buried electric tube blockage detection device and method

Abstract

A buried electric pipe blocking detection device comprises an in-pipe signal unit, a ground detection unit, a winding and unwinding and power supply unit and a control and alarm unit, the in-pipe signal unit comprises a flexible threading pipe, a wire and a magnetic sensitive switch, the tail end of the flexible threading pipe is provided with the magnetic sensitive switch, the magnetic sensitive switch is matched with the ground detection unit, and the control and alarm unit is connected with the ground detection unit. The positive electrode and the negative electrode of the magnetic sensitive switch are connected with one ends of wires respectively, the two wires are located in the flexible threading pipe, the leading-out end of one wire is connected with the control and alarm unit and the positive electrode of the take-up and pay-off and power supply unit in series, and the leading-out section of the other wire is connected with the negative electrode of the take-up and pay-off and power supply unit. The invention further provides a buried electric tube blocking detection method. The method has the advantages of low cost, high precision and good operability.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology, specifically relating to a detection device and method for locating and clearing blockages in concealed electrical conduits within concrete during building decoration and maintenance. Background Technology

[0002] During residential building construction, PVC electrical conduits embedded in concrete floor slabs or walls often become clogged due to concrete pouring or falling foreign objects. Effectively locating the blockage is crucial for subsequent repairs, but currently used methods have limitations in residential construction. The main existing methods for locating and clearing blockages are as follows:

[0003] Traditional physical detection methods (wire probing method) involve inserting a wire into the blocked pipe, pulling it out after encountering resistance, measuring the insertion length, and then estimating the blockage location based on the pre-embedded drawings. This method is extremely inaccurate. Because the actual pre-embedded pipeline often deviates from the design drawings, the location calculated based on the drawings and length is often inaccurate. To find the exact blockage, construction workers often need to chisel away a large area of ​​concrete, causing unnecessary damage to the building structure, and the repair work is extensive and inefficient. The entire process is highly dependent on the operator's experience and has poor reliability.

[0004] Professional detection methods: Commercially available professional equipment is based on different principles, but generally suffers from issues of cost, accuracy, or applicability. Specific methods are as follows: 1) Electromagnetic signal detection method: This consists of a signal transmitter inserted into the pipe and a ground receiver. In use, the transmitter, connected to a power source, is inserted into the pre-buried conduit. After the transmitter reaches the blockage point, the receiver is moved across the wall or ground to detect the signal. When the receiver receives the transmitter's signal, the blockage point is below. Its disadvantages are that the detection signal is easily interfered with by the steel reinforcement mesh and other pipelines in the floor slab, the positioning accuracy is usually only within a few centimeters, and the probe is easily damaged, resulting in high maintenance costs. 2) Pipe endoscope (visual method): This technology can directly display the condition inside the pipe with high accuracy. However, rigid endoscope probes are difficult to pass through the small-diameter sharp bends common in residential buried conduits, and the equipment is expensive. Therefore, its application in small-diameter pipe scenarios in residential buildings is limited, and it is more suitable for large-diameter industrial pipes. 3) Other precision instruments (such as ground-penetrating radar): Although it can achieve trenchless detection, the equipment is extremely expensive, difficult to distinguish in dense residential structures, requires high professional expertise, has low cost-effectiveness, and is difficult to popularize.

[0005] In summary, existing methods struggle to balance cost-effectiveness, accuracy, and applicability when dealing with the problem of clogged concealed conduits in residential projects. Traditional methods are often destructive and inaccurate, while specialized instruments are susceptible to interference, prohibitively expensive, or unable to navigate bends. Therefore, the market urgently needs a low-cost, highly accurate (centimeter-level) detection device or solution that can flexibly handle small-diameter, multi-bend conduits in residential buildings. Summary of the Invention

[0006] To overcome the shortcomings of existing methods for detecting blockages in buried electrical conduits, which cannot simultaneously balance cost, accuracy, and operability, this invention provides a device and method for detecting blockages in buried electrical conduits that combines low cost, high accuracy, and good operability.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A device for detecting blockage in buried electrical conduits includes an in-conduit signal unit, a ground detection unit, a retraction and power supply unit, and a control and alarm unit. The in-conduit signal unit includes a flexible conduit, wires, and a magnetic switch (reed switch detection head). The magnetic switch is installed at the end of the flexible conduit and works in conjunction with the ground detection unit. The positive and negative poles of the reed switch detection head are respectively connected to one end of the wires. Two wires are located inside the flexible conduit. The lead-out end of one wire is connected in series with the positive pole of the control and alarm unit and the retraction and power supply unit, while the lead-out end of the other wire is connected to the negative pole of the retraction and power supply unit.

[0009] Furthermore, the winding and power supply unit includes a winder and a power source. The winder includes a wire stop plate, a winding roller, a wire threading hole, and a crank handle. The beginning end of the flexible wire threading tube is fixed in the wire threading hole of the winding roller. The crank handle is located on the rotating shaft of the winding roller. By rotating the crank handle, the flexible wire threading tube is wound onto the winding roller.

[0010] Furthermore, the signal unit inside the tube also includes a sealing rubber cap, and the magnetic switch is sealed and installed at the end of the flexible conduit, with the end of the flexible conduit sealed with a sealing rubber cap.

[0011] Furthermore, the magnetic switch is a reed switch detection head, which includes a reed switch fixing box, a reed switch, and a metal clip. The reed switch is fixed in the reed switch fixing box by the metal clip.

[0012] Preferably, the reed switch fixing box is a rectangular plastic box. The reed switch includes a reed and pins. There are two reeds inside the reed switch, and the reeds are led out by two pins. The wire is electrically connected to two metal clips, and the two pins are inserted into the two metal clips.

[0013] The ground detection unit is a handheld detector, which includes a handheld stick and a rubidium magnet, with the rubidium magnet installed at the lower end of the handheld stick.

[0014] Preferably, the handheld telescopic rod is a handheld telescopic rod, the bottom of the handheld telescopic rod is screw-shaped, the neodymium magnet is provided with a screw hole, and the bottom of the handheld telescopic rod is threaded into the screw hole of the neodymium magnet.

[0015] Preferably, the control and alarm unit includes a relay and a buzzer, which are connected in series.

[0016] A method for detecting blockage in buried electrical conduits, the method comprising the following steps:

[0017] Step 1, Device Preparation and Testing: Assemble and connect the buried electrical conduit blockage detection device, and conduct a functional test;

[0018] Step 2, Probe delivery and preliminary positioning: The flexible conduit with a magnetic switch encapsulated at the end is pushed inward along the blocked buried conduit until it can no longer go deeper. At this point, the probe has reached the blockage point, thus determining the approximate planar area where the blockage point is located.

[0019] Step 3: Detect and mark the on / off critical point: Move the ground detection unit in the corresponding rough area on the floor surface. When the control and alarm unit alarms for the first time, finely adjust the position of the ground detection unit near this point to find the critical position of the alarm, and mark this precise point on the floor surface as the on / off critical point.

[0020] Step 4, Location Output and Repair Construction: Subsequent repair construction only requires minimal chiseling around this critical point of blockage to expose the blockage and treat it, minimizing damage to the building structure.

[0021] Preferably, in step 3, a three-point positioning method is used to accurately locate the blockage point, as follows:

[0022] Step 3.1: Detect and mark the first on / off critical point: In the rough area corresponding to the floor surface, move the ground detection unit. When the control and alarm unit alarms for the first time, finely adjust the position of the ground detection unit near this point to find the critical position of the alarm, and mark this precise point on the floor surface as point A.

[0023] Step 3.2: Detect and mark the second and third on / off critical points:

[0024] 3.2.1) Change the position of the ground detection unit approaching the probe from different directions;

[0025] 3.2.2) Repeat the detailed search process in step 3.1 to find the other two critical locations of the alarm, and mark them as points B and C on the floor surface. Points A, B and C are not in the same location.

[0026] Step 3.3: Calculate the vertical projection position of the blockage point. The process is as follows:

[0027] 3.3.1) Connect points A, B, and C marked on the floor slab surface to form triangle △ABC;

[0028] 3.3.2) Construct the circumcircle of triangle △ABC;

[0029] 3.3.3) The center O of the circumscribed circle is the precise vertical projection position of the blockage point in the buried electrical conduit onto the floor surface.

[0030] This invention utilizes modular integration of commonly available standard components, resulting in low manufacturing costs. The design emphasizes easy replacement of vulnerable parts, significantly reducing usage and maintenance costs. Based on a stable magnetic field induction principle and a simple three-point positioning geometry, it achieves accurate detection. The device has a simple structure and intuitive operation, allowing on-site construction personnel to quickly master and use it. Specifically designed for the scenario of concealed electrical conduits in buildings, it effectively solves the problem of locating blockages caused by concrete pouring or falling foreign objects, fundamentally changing the outdated operation method that relies on large-scale demolition.

[0031] The beneficial effects of this invention are mainly reflected in:

[0032] 1) High positioning accuracy: It innovatively combines magnetic induction triggering with the geometric principle of "three points to determine a circle", realizing a qualitative change from "region judgment" to "point coordinate determination" of the blockage point, with positioning accuracy reaching the centimeter level, solving the fundamental problem of fuzzy positioning in traditional methods.

[0033] 2) Minimal damage to building structure: Through precise positioning, the scope of subsequent repairs can be reduced from a large area to a minimum working point, maximizing the protection of the structural integrity and appearance of the building floor or walls, and reducing the amount of repair work.

[0034] 3) Significantly improved detection efficiency and economic benefits: This method is quick to operate, with single-point location typically completed within minutes. Compared to traditional large-area blind excavation, it can improve overall construction efficiency by several times. Furthermore, the device is inexpensive to manufacture and easy to maintain, saving substantial labor and structural repair costs, resulting in outstanding overall economic benefits.

[0035] 4) High reliability and easy operation: The test results are objectively derived from physical principles and geometric calculations, unaffected by the operator's subjective experience, resulting in high repeatability and success rate. The device has a simple structure, and the method is easy to understand and master. Ordinary workers can operate it proficiently after brief training, facilitating its widespread application on construction sites.

[0036] 5) Extremely low cost: The device has a simple structure, low manufacturing cost, and is easy to maintain and replace; at the same time, it saves a lot of labor and structural repair costs, resulting in significant overall economic benefits. Attached Figure Description

[0037] Figure 1 This is a schematic diagram illustrating the application of a device for detecting blockages in buried electrical conduits.

[0038] Figure 2 This is the circuit diagram (i.e., loop diagram) of a device for detecting blockages in buried electrical conduits.

[0039] Figure 3 This is a schematic diagram of a wire winder, where (a) is a front view, (b) is a rear view, and (c) is a side view.

[0040] Figure 4 This is a schematic diagram of the assembly of the detection device (assembly diagram of power supply, relay, buzzer, conduit, reed switch detection head, and thin wire), where (a) is a side view and (b) is a front view.

[0041] Figure 5 This is a power supply diagram.

[0042] Figure 6 This is a schematic diagram of a reed switch detection head, where (a) is a reed switch and (b) is a reed switch cartridge.

[0043] Figure 7 This is a schematic diagram of a sealing rubber cap.

[0044] Figure 8 This is a schematic diagram of a handheld detector.

[0045] Figure 9 These are a schematic diagram and a schematic diagram of three-point positioning, where (a) is a schematic diagram and (b) is a schematic diagram.

[0046] Figure 10 This is a construction process flow diagram for detecting blockages in buried electrical conduits.

[0047] The attached diagram is labeled as follows: 1-Winder; 11-Wire stop plate; 12-Winding roller; 121-Wire hole; 13-Handle; 2-Power supply; 21-Battery box; 22-12V battery; 3-Relay; 4-Buzzer; 5-Flexible conduit; 6-Fine wire; 7-Magnetic switch (reed switch detection head); 71-Reed switch fixing box; 72-Reed switch; 721-Reed leaflet; 722-Pin; 73-Metal clip; 8-Sealing rubber cap; 9-Ground detection unit; 91-Handheld rod; 92-Neodymium magnet. A, B, C-Induction critical point; D-Buried conduit; E-Concrete floor slab (wall panel); F-(Blocking foreign object). Detailed Implementation

[0048] The present invention will now be further described with reference to the accompanying drawings.

[0049] Reference Figures 1-10A device for detecting blockage in buried electrical conduits includes an in-conduit signal unit, a ground detection unit, a retraction and power supply unit, and a control and alarm unit. The in-conduit signal unit includes a flexible conduit 5 (a plastic conduit is used in this embodiment), wires 6, and a magnetic switch 7. The magnetic switch 7 is installed at the end of the flexible conduit 5. The magnetic switch 7 cooperates with the ground detection unit 9. The positive and negative poles of the magnetic switch 7 are respectively connected to one end of the wires 6. The two wires 6 are located inside the flexible conduit 5. The lead-out end of one wire is connected in series with the positive pole of the control and alarm unit and the retraction and power supply unit, and the lead-out section of the other wire is connected to the negative pole of the retraction and power supply unit.

[0050] The winding and power supply unit includes a winder 1 and a power supply 2. The winder 1 includes a wire stop plate 11, a winding roller 12, a wire threading hole 121 and a crank handle 13. The beginning end of the flexible wire threading tube 5 is fixed in the wire threading hole 121 of the winding roller 12. The crank handle 13 is located on the rotating shaft of the winding roller 12. By rotating the crank handle 13, the flexible wire threading tube 5 is wound onto the winding roller 12.

[0051] The signal unit inside the tube also includes a sealing rubber cap 8. The magnetic switch 7 is sealed and installed at the end of the flexible conduit 5. The end of the flexible conduit 5 is sealed with the sealing rubber cap 8.

[0052] The magnetic switch 7 is a reed switch detection head, which includes a reed switch fixing box 71, a reed switch 72 and a metal clip 73. The reed switch 72 is fixed in the reed switch fixing box 71 by the metal clip 73.

[0053] Preferably, the reed switch 72 has two reeds 721 inside, and the reeds 721 are led out by two pins 722. The wire 6 is soldered to two metal clips 73, and the two pins 722 are inserted into the two metal clips 73. The reed switch fixing box 71 is a rectangular plastic box.

[0054] The ground detection unit 9 is a handheld detector, which includes a handheld stick 91 and a rubidium magnet 92. The rubidium magnet 92 is installed at the lower end of the handheld stick 91.

[0055] Preferably, the handheld rod 91 is a handheld telescopic rod, the bottom of the handheld telescopic rod is screw rod shaped, the neodymium magnet 92 is provided with a screw hole, and the bottom of the handheld telescopic rod is threaded into the screw hole of the neodymium magnet 92.

[0056] Preferably, the control and alarm unit includes a relay 3 and a buzzer 4, which are connected in series.

[0057] The core detection mechanism of the device in this embodiment is as follows: the signal unit inside the tube has a built-in magnetic switch 7 (reed switch detection head). When the detection point is directly above it, the magnetic field generated by the neodymium magnet held by the ground detection unit will penetrate the building floor slab and trigger the switch. After the switch is triggered, an audible alarm circuit (buzzer 4) is connected, thereby prompting the detector to accurately locate the floor surface directly above the blockage point.

[0058] The winding and power supply unit of this embodiment includes a winder 1 (including 11-wire stop plate, 12-winding roller, 121-threading hole and 13-crank handle) and a power supply 2 (21-battery box and 22-12V battery). The in-tube signal unit includes a plastic threading tube 5, a thin wire 6, a reed switch detection head 7 (including 71-reed switch fixing box, 72-reed switch, 721-reed leaflet; 722-pin, 73-metal clip) and a sealing rubber cap 8. The ground detection unit 9 is a handheld magnet detector (including 91-handheld telescopic rod, 92-rubidium magnet). The control and alarm unit includes a relay 3 and a buzzer 4.

[0059] The mechanical winding structure of this embodiment is as follows: the beginning end of the flexible threading tube 5 is fixed inside the threading hole 121 of the winding drum 12. By turning the crank handle 13, the flexible threading tube 5 can be neatly wound onto the winding drum 12, making it easy to carry and quickly retrieve.

[0060] The core circuit connection in this embodiment is as follows: Figure 2 As shown, power supply 2, relay 3, buzzer 4, and reed switch detection head 7 are connected in series via wire 6 passing through the flexible conduit 5, forming a normally open circuit. The reed switch 72 is connected in series in this circuit as a magnetic switch.

[0061] In this embodiment, the reed switch 72 is fixed inside the reed switch fixing box 71 by a metal clip 73, and the reed switch detection head 7 is completely sealed and installed at the end of a flexible conduit 5. The end of the flexible conduit 5 is sealed with the sealing rubber cap 8, which provides a sealing and protection function for the reed switch detection head 7. The wire 6 passes through the flexible conduit 5 to complete the electrical connection between the components.

[0062] The reed switch detection head 7 of this embodiment consists of a plastic reed switch mounting box 71, a reed switch 72, and metal clips 73. The reed switch 72 has a glass outer shell and two reed tabs 721 inside. The reed tabs 721 are led out by two pins 722. The wire 6 is connected to the two metal clips 73 by soldering. In use, the reed switch 72 is pressed into the reed switch mounting box 71, and the two positive and negative pins 722 of the reed switch are inserted into the metal clips 73 to complete the connection between the reed switch 72 and the circuit. If several reed switches 72 are damaged, simply remove the damaged reed switch and insert a new one for quick replacement. This clip connection method allows for quick replacement of damaged reed switches without soldering, greatly improving maintenance convenience.

[0063] The ground detection unit 9 is a handheld detector, consisting of a handheld rod 91 and a neodymium magnet 92. The handheld rod 91 is a telescopic rod that can be extended and retracted as needed to adapt to different operating environments. The bottom of the handheld rod 91 is screw-shaped and conforms to the screw hole on the neodymium magnet 92, allowing for quick replacement of neodymium magnets 92 with different strengths for different slab thicknesses. The telescopic rod can adapt to different height operating requirements; the threaded connection structure allows for convenient replacement of magnets with different magnetic field strengths based on the floor slab thickness or material, thereby optimizing the detection effect.

[0064] The winding device 1 consists of two left and right wire-blocking plates 11, a middle winding roller 12, and a crank handle 13. The winding roller 12 has a hole 121 for threading wire. The power supply 2 consists of a battery box 21 and two 12V batteries 22 (two batteries connected in series).

[0065] The functional relationships and working process in this embodiment are as follows:

[0066] Normal state (when not being tested): When there is no external magnetic field, the reed switch test head 7 has its internal reed 721 contacts in the normally open state, the entire circuit is in the open state, and the buzzer 4 does not work.

[0067] Preparation phase: Insert the signal unit inside the tube (i.e., the flexible conduit 5 with the reed switch detection head 7 encapsulated at the end) into the buried electrical conduit to be tested, and push it forward until it can no longer move (at this time, the reed switch detection head 7 has reached the blockage point).

[0068] Detection phase: The operator moves and scans the area along the route of the pre-buried pipeline by holding the ground detection unit 9 (a retractable handheld rod 91 with a neodymium magnet 92) on the ground or wall.

[0069] Location phase (alarm triggered): When the neodymium magnet 92 moves to the position directly above the reed switch detection head 7 embedded in the wall / floor, the magnetic field penetrates the floor material and magnetizes the reed 721 inside the reed switch 72, causing the normally open circuit to close and conduct, and the buzzer 4 sounds, indicating that the current position below is the location of the blockage.

[0070] This embodiment presents a method for detecting blockages in buried electrical conduits. Based on the aforementioned device and incorporating geometric positioning principles, this method achieves precise location of blockage points in buried electrical conduits and includes the following steps:

[0071] Step 1, Device Preparation and Testing: Assemble and connect the detection device, and perform a functional test. Ensure that when the 92-rubidium magnet of the handheld detector is close to the 7-reed switch detection head, the circuit is connected and the 4-buzzer can emit an alarm sound normally.

[0072] Step 2, Probe Delivery and Preliminary Positioning: Insert the 5-plastic conduit with the 7-reed switch detection head encapsulated at one end into the blocked buried electrical conduit until it cannot be inserted any further. At this point, the probe has reached the blockage point, thus determining the approximate planar area where the blockage point is located.

[0073] Step 3: Detect and mark the critical points for continuity and disconnection. Use the three-point positioning method to accurately locate the blockage point. The process is as follows:

[0074] Step 3.1: Detect and mark the first on / off critical point (point A): Move the handheld detector (rubidium magnet 92) within the corresponding rough area on the floor surface. When the buzzer 4 sounds for the first time ("beep beep"), finely adjust the position of the rubidium magnet 92 near this point to find the critical position where the buzzer 4 just changes from silent to audible, and mark this precise point on the floor surface as point A.

[0075] Step 3.2: Detect and mark the second and third on / off critical points (points B and C):

[0076] 3.2.1) Change the position of the handheld detector as it approaches the probe from different directions (e.g., rotate about 90° or 180° relative to the direction of point A).

[0077] 3.2.2) Repeat the detailed search process in step 3.1 to find the other two critical positions where the buzzer state changes, and mark them as points B and C on the floor surface. Ensure that the three points are not in the same location.

[0078] Step 3.3: Calculate the vertical projection position of the blockage point. The process is as follows:

[0079] 3.3.1) Connect points A, B, and C marked on the floor slab surface to form triangle △ABC.

[0080] 3.3.2) Construct the circumcircle of triangle △ABC.

[0081] 3.3.3) The center O of the circumscribed circle is the precise vertical projection position of the blockage point in the buried electrical conduit onto the floor surface.

[0082] Step 4, Location Output and Repair Construction: Clearly mark the center point O on the floor slab surface. Subsequent repair construction only needs to use this point as the center and carry out minimal chiseling to accurately expose the blockage point for treatment, greatly reducing damage to the building structure.

[0083] The embodiments described in this specification are merely examples of implementations of the inventive concept and are for illustrative purposes only. The scope of protection of this invention should not be considered limited to the specific forms described in these embodiments; rather, it extends to equivalent technical means conceived by those skilled in the art based on the inventive concept.

Claims

1. A device for detecting blockage in buried electrical conduits, characterized in that, The device includes an in-tube signal unit, a ground detection unit, a take-up and power supply unit, and a control and alarm unit. The in-tube signal unit includes a flexible conduit, wires, and a magnetic switch. A magnetic switch is installed at the end of the flexible conduit. The magnetic switch works in conjunction with the ground detection unit. The positive and negative poles of the magnetic switch are respectively connected to one end of the wires. Two wires are located inside the flexible conduit. The lead-out end of one wire is connected in series with the positive pole of the control and alarm unit and the take-up and power supply unit, and the lead-out section of the other wire is connected to the negative pole of the take-up and power supply unit.

2. The device for detecting blockage in buried electrical conduits as described in claim 1, characterized in that, The winding and power supply unit includes a winder and a power supply. The winder includes a wire stop plate, a winding roller, a wire threading hole and a crank handle. The beginning end of the flexible wire threading tube is fixed in the wire threading hole of the winding roller. The crank handle is located on the rotating shaft of the winding roller. By rotating the crank handle, the flexible wire threading tube is wound onto the winding roller.

3. A device for detecting blockage in buried electrical conduits as described in claim 1 or 2, characterized in that, The signal unit inside the tube also includes a sealing rubber cap. The magnetic switch is sealed and installed at the end of the flexible conduit, and the end of the flexible conduit is sealed with a sealing rubber cap.

4. A device for detecting blockage in buried electrical conduits as described in claim 1 or 2, characterized in that, The magnetic switch is a reed switch detection head, which includes a reed switch fixing box, a reed switch and a metal clip. The reed switch is fixed in the reed switch fixing box by the metal clip.

5. The device for detecting blockage in buried electrical conduits as described in claim 4, characterized in that, The reed switch includes a reed and pins. Inside the reed switch are two reeds. The reeds are led out by two pins. The wire is soldered to two metal clips. The two pins are inserted into the two metal clips.

6. A device for detecting blockage in buried electrical conduits as described in claim 1 or 2, characterized in that, The ground detection unit is a handheld detector, which includes a handheld stick and a rubidium magnet, with the rubidium magnet installed at the lower end of the handheld stick.

7. The device for detecting blockage in buried electrical conduits as described in claim 6, characterized in that, The handheld rod is a telescopic handheld rod, the bottom of which is screw-shaped, and the rubidium magnet has a screw hole. The bottom of the handheld telescopic rod is threaded into the screw hole of the rubidium magnet.

8. A device for detecting blockage in buried electrical conduits as described in claim 1 or 2, characterized in that, The control and alarm unit includes a relay and a buzzer, which are connected in series.

9. A detection method implemented by the buried electrical conduit blockage detection device as described in claim 1, characterized in that, The detection method includes the following steps: Step 1, Device Preparation and Testing: Assemble and connect the buried electrical conduit blockage detection device, and conduct a functional test; Step 2, Probe delivery and preliminary positioning: The flexible conduit with a magnetic switch encapsulated at the end is pushed inward along the blocked buried conduit until it can no longer go deeper. At this point, the probe has reached the blockage point, thus determining the approximate planar area where the blockage point is located. Step 3: Detect and mark the on / off critical point: Move the ground detection unit in the corresponding rough area on the floor surface. When the control and alarm unit alarms for the first time, finely adjust the position of the ground detection unit near this point to find the critical position of the alarm, and mark this precise point on the floor surface as the on / off critical point. Step 4, Location Output and Repair Construction: Subsequent repair construction only requires minimal chiseling around this critical point of blockage to expose the blockage and treat it, minimizing damage to the building structure.

10. The detection method as described in claim 9, characterized in that, In step 3, the three-point positioning method is used to accurately locate the blockage point, and the process is as follows: Step 3.1: Detect and mark the first on / off critical point: In the rough area corresponding to the floor surface, move the ground detection unit. When the control and alarm unit alarms for the first time, finely adjust the position of the ground detection unit near this point to find the critical position of the alarm, and mark this precise point on the floor surface as point A. Step 3.2: Detect and mark the second and third on / off critical points: 3.2.1) Change the position of the ground detection unit approaching the probe from different directions; 3.2.2) Repeat the detailed search process in step 3.1 to find the other two critical locations of the alarm, and mark them as points B and C on the floor surface. Points A, B and C are not in the same location. Step 3.3: Calculate the vertical projection position of the blockage point. The process is as follows: 3.3.1) Connect points A, B, and C marked on the floor slab surface to form triangle △ABC; 3.3.2) Construct the circumcircle of triangle △ABC; 3.3.3) The center O of the circumscribed circle is the precise vertical projection position of the blockage point in the buried electrical conduit onto the floor surface.

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