Signal redundancy ball passing detection sensor

Abstract

The invention relates to the technical field of nuclear power, and discloses a signal redundancy ball passing detection sensor which comprises two semi-cylindrical shells, one sides of the shells are hinged, and the other sides of the shells can be locked and movably opened; a junction box is arranged outside the movable end of the shell, two semi-cylindrical frameworks are arranged in the shell, grooves are formed in the frameworks, at least one coil is arranged in the grooves, the coils wrap a ball passing pipeline, and fuel balls pass through the ball passing pipeline. The winding coils are distributed in the circumferential direction of the ball passing pipeline, a uniform magnetic field is formed, the detection capability on balls in different states is achieved, and the accuracy of ball passing detection is guaranteed; a partition plate is arranged between the coil and the ball passing pipeline, is made of metal materials, has a certain protection effect on the sensor coil, and prevents the sensor coil from being abraded by the pipeline and affecting the performance of the sensor.

Description

Technical Field

[0001] The invention relates to the field of nuclear power, and in particular to a signal redundant ball passing detection sensor. Background Art

[0002] The HTGR is a fourth-generation reactor that uses spherical fuel elements (fuel balls) and has a very high core outlet temperature. Before the fuel balls reach the predetermined burnup depth, they pass through the reactor core an average of 15 times. Then, the elements that exceed the burnup depth limit will be marked as spent fuel elements and sent to the spent fuel storage system through the ball pipeline system. In addition, fresh fuel balls are added through the ball pipeline system.

[0003] The fuel element inspection method currently used on pebble bed HTGRs is the eddy current inspection method.

[0004] The existing Chinese patent with publication number CN110006992A discloses a through-type eddy current sensor and detection method, including a skeleton, a detection coil and an excitation coil, the detection coil and the excitation coil are both wound around the skeleton, and the detection coil is located between the skeleton and the excitation coil; the detection coil includes a first detection coil, a second detection coil, a third detection coil and a fourth detection coil connected in sequence, the winding direction of the first detection coil is the same as the winding direction of the third detection coil, the winding direction of the second detection coil is the same as the winding direction of the fourth detection coil, and the winding direction of the first detection coil is opposite to the winding direction of the second detection coil.

[0005] The defects of the prior art are:

[0006] 1. The technical structure only introduces the coil winding method, and does not introduce any content on the post-processing and fixing of the coil. If the invention content is used for eddy current detection, the coil is easy to loosen, which may cause the sensor to fail;

[0007] 2. For high-temperature pipelines, there is no shielding between the non-metallic materials of the skeleton and windings and the pipelines in this technology, which can easily cause material volatilization and aging, resulting in aging;

[0008] 3. This technology has 5 sets of coils: the first detection coil, the second detection coil, the third detection coil, the fourth detection coil and the absolute coil; different coils have different winding directions and the number of turns is not exactly the same, which will cause great difficulties in the processing process;

[0009] 4. The outer surface of the skeleton of this technology is concave inward in the circumferential direction to form several circles of positioning grooves for winding the absolute coil and the detection coil. The grooves will cause the coils to be unevenly distributed on the skeleton, and the experimental data measured by the coils wound by different people will be quite different. Summary of the invention

[0010] In order to overcome or alleviate one or more of the above technical problems, the purpose of the present invention is to provide a signal redundant ball passing detection sensor.

[0011] The present invention provides the following technical solutions:

[0012] A signal redundant ball passing detection sensor comprises two semi-cylindrical shells, one side of the shells is hinged, and the other side can be locked and opened movably; a junction box is arranged outside the movable end of the shells, and two semi-cylindrical frames are arranged inside the shells, and grooves are arranged inside the frames, and at least one coil is arranged inside the groove, and the coil wraps a ball passing pipe, and a fuel ball passes through the ball passing pipe.

[0013] According to some embodiments, a semi-cylindrical metal partition is fixed between the semi-cylindrical frame and the shell.

[0014] According to some embodiments, the substrate for manufacturing the coil is selected from polyimide.

[0015] According to some embodiments, two of the coils are cross-over stacked to form four equivalent annular coils.

[0016] According to some embodiments, the coil specification is selected from 80 turns and a pitch of 40 mm.

[0017] According to some embodiments, the metal partition is connected to the housing by welding.

[0018] According to some embodiments, the metal separator is a stainless steel plate with a thickness ranging from 1 to 3 mm.

[0019] According to some embodiments, the material used to make the skeleton is selected from polyetheretherketone or polyimide.

[0020] According to some embodiments, inner diameter fine-tuning devices are provided at the arc-shaped middle portions of the upper and lower sides of the shell.

[0021] According to some embodiments, a grounding bolt is disposed on the lower side of the housing for grounding protection of the signal redundant ball passing detection sensor.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The sensor coil of the present invention adopts a flexible polyimide material and is attached to the circuit surface, which can improve the structure of the sensor coil's radiation resistance and ensure that the sensor coil has stable performance under high temperature conditions. By using two coils to cross and overlap, the same ball can generate two cycles of quasi-sine ball signals, and the two waveforms have redundant characteristics, which can significantly enhance the accuracy and reliability of counting.

[0024] A partition is provided between the sensor coil and the ball-passing pipe of the present invention. The partition is made of metal material, which has a certain protective effect on the sensor coil, preventing the sensor coil from being worn by the pipe and affecting the sensor performance. At the same time, due to the high temperature characteristics of the measured object, the metal parts conduct heat, effectively reducing the temperature at the sensor coil. The sensor coil is encapsulated and protected by a thin layer of metal inner shell, which protects the sensor coil structure and improves the reliability of the eddy current coil. The metal inner shell encapsulation makes it difficult for the sensor coil to fail due to vibration.

[0025] The skeleton of the present invention adopts materials such as polyetheretherketone or polyimide, which can reduce the overall mass of the sensor on the one hand, and protect the coil on the other hand (when the stainless steel material is processed with poor quality, it is easy to cut the coil insulation material)

[0026] The winding coils of the present invention are distributed circumferentially along the ball-passing pipeline to form a uniform magnetic field, and are capable of detecting balls in different states, thereby ensuring the accuracy of the ball-passing detection.

[0027] The hinge structure makes the sensor installation, inspection, disassembly, maintenance and replacement simple and convenient. The inner diameter can be easily adjusted through the inner diameter fine-tuning device, and the coil is firmly fixed. The sensor is installed on the outside of the pipeline without destroying the integrity of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the overall structure of a signal redundant ball passing detection sensor provided in an embodiment of the present invention.

[0029] Figure 2 A schematic diagram of a signal redundant ball passing detection sensor and a ball passing test provided in an embodiment of the present invention.

[0030] Figure 3 An exploded diagram of a ball passing test of a signal redundant ball passing detection sensor provided in an embodiment of the present invention.

[0031] Figure 4 A schematic diagram of a fuel ball provided in an embodiment of the present invention passing through four equivalent coils in sequence.

[0032] Figure 5 A schematic diagram of the working principle of the redundant ball passing sensor provided in an embodiment of the present invention.

[0033] Figure 6 A schematic diagram of redundant ball passing signals provided in an embodiment of the present invention.

[0034] In the figure:

[0035] 1. Stainless steel sheet; 2. Frame; 3. Inner diameter fine-tuning device; 4. Wire box; 5. Locking bolt; 6. Pin shaft; 7. Grounding bolt; 8. Casing; 9. Coil; 10. Ball passage pipe; 11. Fuel ball. DETAILED DESCRIPTION

[0036] The technical principle of the signal redundant ball passing detection sensor provided by the present invention is: use at least one, preferably two, annular coils, overlap on the ball passing pipe to form an equivalent coil, and obtain the ball passing information by calculating the difference in eddy current effects between the coils. The two annular coils are cross-over and overlapped together, equivalently wrapped on the ball passing pipe, forming two groups of coils (A, B), equivalent to 4 annular coils A1, B1, A2, B2. The two groups of coils are excited by the same frequency alternating electromagnetic field, and the difference in eddy currents generated on coils A and B is calculated. When the ball passes, the ball passes through A1, B1, A2, B2 in turn, and the difference in eddy current effects reaches a significant peak value, thereby generating two ball passing signals similar to sinusoidal cycles. Any one of the two ball passing signals can be used to determine the ball passing information, and the two ball passing signals are redundant with each other.

[0037] Two ring coils overlap and are embedded in the structure on both sides of the sensor frame, and are encapsulated and protected by a thin layer of stainless steel material. The sensor has a hinge structure on both sides. When the hinge is open, the sensor can be installed on the pipeline, and when the hinge is closed, the sensor holds the pipeline tightly.

[0038] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0039] The present invention will be further described below in conjunction with the accompanying drawings.

[0040] Example 1

[0041] like Figures 1 to 3 , which is the assembly diagram and assembly explosion diagram of the signal redundant ball detection sensor provided in this embodiment, hereinafter referred to as the sensor. The structure of the sensor is described as follows:

[0042] The sensor comprises two semi-cylindrical shells 8, one side of the shell 8 is provided with a wire box 4, and the wire box 4 is provided with a wiring terminal and a wiring, wherein the wiring is used to connect the coil 9 with an external secondary instrument, the shell 8 is provided with a frame 2 and a coil 9, the two semi-cylindrical frames 2 are provided with grooves facing inward, and the coil 9 is placed in the grooves of the frame 2, two semi-ring-shaped stainless steel sheets 1 seal the coil 9 and the frame 2 inside the shell 8, and the stainless steel sheet 1 is welded to the shell body 8 by welding, and the stainless steel sheet 1 forms an inner shell; the function of the inner shell is to provide mechanical protection and heat conduction for the coil 9, and to seal the frame 2 and the coil 9 therein. The frame 2 is fixed in the shell 8 by bolt connection. The inner diameter fine-tuning device 3 is provided in the arc-shaped middle part of the upper and lower sides of the shell 8. Because there are machining errors in the various components of the sensor and the diameter of the ball-passing pipe 10, in order to ensure that the sensor can be accurately fixed on the ball-passing pipe 10, the inner diameter of the shell 8 of the sensor can be fine-tuned by adjusting the bolts on the inner diameter fine-tuning device 3, so that the sensor as a whole can be firmly fixed on the ball-passing pipe 10. The locking bolt 5 is arranged on the ribs on the side of the housing 8, and is used to lock the housing 8 on the ball-passing pipe 10 to be measured. The thickness of the stainless steel sheet 1 is 1-3 mm; the grounding bolt 7 is arranged on the ribs on the side of the housing 8, and is used to ground the sensor.

[0043] The frame 2 and the housing 8 are connected by bolts to facilitate installation and disassembly.

[0044] One side of the two semicircular shells 8 can be fixedly connected and movably opened and closed, and the other side is hinged through a pin 6 to facilitate installation and disassembly.

[0045] The frame 2 is made of radiation-resistant material, and the manufacturing material is polyetheretherketone or polyimide, which can adapt to high temperature environment and environment with high insulation requirements.

[0046] Coil 9 is an internal induction coil of the signal redundant ball passing detection sensor, which is used to generate a uniform electromagnetic field and generate a response ball passing signal after the ball passes through.

[0047] Figure 4 Two cross-over coils 9 are wrapped around the ball-passing pipe 10 to form four annular equivalent coils, A1, B1, A2, B2 from top to bottom. When the fuel ball 11 passes through the windings A1, B1, A2, B2 in sequence, a two-cycle quasi-sine ball-passing signal is formed.

[0048] Figure 5 This is a typical redundant ball passing signal, where the horizontal axis is time and the vertical axis is the amplitude of the signal. The figure shows a double sine waveform with a high signal-to-noise ratio.

[0049] The detection process of the signal redundant ball passing detection sensor provided in this embodiment is described as follows:

[0050] The eddy current detection method is used to detect the passage of the fuel ball in the pipeline. Under the excitation of the alternating electromagnetic field, the difference between the impedance of windings A and B is constant. When the fuel ball is in the winding, the fuel ball generates eddy currents, which form a magnetic field, which in turn causes the impedance of the detection coil to change. When the fuel ball passes through the sensor, especially at the four equivalent detection coils A1, B1, A2, and B2, the impedance formed changes significantly from when there is no fuel ball on the A and B windings. In this way, it can be determined whether there is a fuel ball passing through. When the fuel ball passes through A1, B1, A2, and B2 in turn, a change signal of the A and B windings that changes continuously like two periodic sine waves is formed.

[0051] The two ball passing signals similar to sine cycles are formed. Figure 5 The information in the figure includes but is not limited to the amplitude and speed of the ball passing signal. The change process of the ball passing signal also includes the shape information of the ball, thereby judging whether the ball is damaged.

[0052] Two similar sine-cycle ball passing signals are formed. Any of the two ball passing signals can be used to determine the ball passing information, and the two ball passing signals are redundant with each other. Therefore, the ball passing information formed by the same ball on the sensor can be redundantly judged, which significantly improves the accuracy and reliability of ball passing detection.

[0053] The coil 9 of the sensor is fixed in the grooves of the two radiation-resistant frames 2 and embedded in the stainless steel material of the shell 8. At the same time, the radiation-resistant frame 2 is connected to the shell 8 by bolts.

[0054] Two stainless steel sheets 1 are used to isolate the coil 9 from the ball pipe 10 to form the inner shell of the redundant sensor. The inner shell mechanically protects the coil 9 and fixes the coil 9 in the groove of the frame 2, while conducting the heat of the ball pipe 10 to the outer shell 8.

[0055] The two semicircular housings 8 of the sensor are connected by hinges, and the overlapping parts of the coils 9 overlap when the hinges are closed. Outside the winding part surrounding the pipeline, the generated electromagnetic fields cancel each other out, forming an equivalent annular coil structure surrounding the pipeline.

[0056] When the hinge is opened, the signal redundant ball passing detection sensor provided in this embodiment is externally mounted on the ball passing pipe 10, thereby realizing rapid installation, maintenance and replacement without damaging the pipe itself.

[0057] The single coil 9 is selected from a coil with 80 turns and a coil spacing of 40 mm. Compared with coils 9 of other specifications, it has better test sensitivity and can generate a high signal-to-noise ratio signal.

[0058] Example 2

[0059] In order to further illustrate the advantages of the signal redundant ball detection sensor provided in Example 1, this example is based on theoretical analysis and actual coil test verification to prove that the coil group with 80 turns and 40mm coil spacing is the best coil specification. The coil 9 of the above specification is selected for sensor design and production, and passed the test verification. The specific steps of verification are as follows:

[0060] The sensor is produced according to the structure of the signal redundant ball detection sensor described in Example 1. In order to further verify the function of the sensor, the instrument is connected. Figure 5 The signal line of the sensor is connected to the secondary instrument through the junction box 4. After the secondary instrument processes the signal collected by the sensor, it is introduced into the signal collection device for signal collection.

[0061] The fuel ball 11 passes through the ball passing pipe 10 at a certain speed, and the eddy current detection method is used to detect the passing state of the fuel ball 11 in the pipe. Under the excitation of the alternating electromagnetic field, when the fuel ball 11 passes through the ball, the difference in the eddy current effect between the coils 9 reaches a significant peak.

[0062] The above-mentioned significant peak value is transmitted to the secondary instrument through the wire, and the secondary instrument further processes the voltage peak value through functions such as filtering and amplification.

[0063] The processed voltage peak is displayed on the signal acquisition device. Figure 6 As shown, the signal-to-noise ratio is high, and the peak-to-peak value reaches 18.4V, which proves that the fuel ball 11 has been detected passing through the sensor and a relatively accurate sinusoidal signal has been generated.

[0064] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A signal redundant ball detection sensor, characterized in that: It includes two semi-cylindrical shells, one side of which is hinged, and the other side can be locked and opened movably; a junction box is provided on the outside of the movable end of the shell, and two semi-cylindrical frames are provided inside the shell, each frame has a groove, and at least one coil is provided in the groove, and the coil wraps a ball-passing pipe, and the fuel ball passes through the ball-passing pipe.

2. The signal redundant ball passing detection sensor according to claim 1, characterized in that: A semi-cylindrical metal partition is fixedly arranged between the semi-cylindrical frame and the shell.

3. The signal redundant ball passing detection sensor according to claim 2, characterized in that: The substrate for manufacturing the coil is selected from polyimide.

4. The signal redundant ball passing detection sensor according to claim 3, characterized in that: The two coils are cross-over and overlapped to form four equivalent annular coils.

5. The signal redundant ball passing detection sensor according to claim 4, characterized in that: The coil specification is selected to be 80 turns and the spacing is 40 mm.

6. The signal redundant ball passing detection sensor according to claim 2, characterized in that: The metal partition is connected to the shell by welding.

7. The signal redundant ball passing detection sensor according to claim 6, characterized in that: The metal partition is a stainless steel plate with a thickness ranging from 1 to 3 mm.

8. The signal redundant ball passing detection sensor according to claim 1, characterized in that: The material for making the frame is selected from polyetheretherketone or polyimide.

9. The signal redundant ball passing detection sensor according to claim 1, characterized in that: The arc-shaped middle parts of the upper and lower sides of the shell are both provided with inner diameter fine-tuning devices.

10. The signal redundant ball passing detection sensor according to claims 1 to 9, characterized in that: A grounding bolt is arranged on the lower side of the housing and is used for grounding protection of the signal redundant ball-passing detection sensor.

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