Eddy current sensor

Abstract

The eddy current sensor comprises a probe and a front-end device, the probe comprises a coil, a probe box body and a shielding shell, the coil is arranged in the probe box body, the space between the coil and the probe box body is filled with high-temperature-resistant epoxy resin, and the probe box body is arranged in a cavity of the shielding shell; and the probe is electrically connected with the front-end device through a cable. According to the eddy current sensor disclosed by the invention, the coil is fixed in the probe box body through the high-temperature-resistant epoxy resin, so that the structure of the probe is more stable, and the temperature resistance and the stability of the probe can be improved; by arranging the shielding shell, external electromagnetic interference can be reduced, the anti-interference capability is improved, and the measurement precision can be improved.

Description

Technical Field

[0001] This application relates to the field of nuclear power turbine technology, and more specifically, to an eddy current sensor. Background Technology

[0002] There is a certain gap between the axial moving and stationary parts of the steam turbine. When steam enters the steam turbine, the expansion amounts of the two parts are different. If this expansion difference exceeds the design value, it will cause the moving and stationary parts of the steam turbine to come into contact. In order to prevent this phenomenon from occurring in the high-pressure cylinder, an eddy current sensor is needed to monitor the difference between the absolute expansion of the rotor and the high-pressure cylinder body. This difference is called high expansion. Eddy current sensors are usually used for monitoring. However, existing eddy current sensors have the problem of low measurement accuracy.

[0003] Therefore, how to improve the measurement accuracy of eddy current sensors has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide an eddy current sensor to improve measurement accuracy.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] An eddy current sensor, comprising:

[0007] The probe includes a coil, a probe housing, and a shielding shell. The coil is disposed in the probe housing, and high-temperature resistant epoxy resin is filled between the coil and the probe housing. The probe housing is disposed in the cavity of the shielding shell.

[0008] The preamplifier is electrically connected to the probe via a cable.

[0009] Optionally, in the above-mentioned eddy current sensor, the probe is rectangular in shape.

[0010] Optionally, in the above-mentioned eddy current sensor, the preamplifier includes a preamplifier housing, a preamplifier cover, and a circuit board. The preamplifier cover is detachably connected to the preamplifier housing, the circuit board is disposed inside the preamplifier housing, one end of the cable is connected to the coil, and the other end is connected to the circuit board.

[0011] Optionally, in the above-mentioned eddy current sensor, the preamplifier housing is provided with an RF connector socket that connects to the circuit board, and the cable is provided with an RF connector plug that can connect to the RF connector socket.

[0012] Optionally, in the above-mentioned eddy current sensor, an aviation socket is provided on the preamplifier housing, and the aviation socket is connected to the data display.

[0013] Optionally, in the above-mentioned eddy current sensor, the preamplifier housing is integrally formed by casting or stamping.

[0014] Optionally, in the above-mentioned eddy current sensor, a cable sheath is provided on the outside of the cable, and the cable sheath is detachably or non-detachably connected to the shielding housing.

[0015] Optionally, in the above-mentioned eddy current sensor, the cable sheath is detachably connected to the shielding housing, the shielding housing is provided with a locking nut, and the cable sheath is provided with an external thread that mates with the locking nut; or,

[0016] One of the shielding housing and the cable sheath is provided with a buckle, and the other is provided with a slot that cooperates with the buckle.

[0017] Optionally, in the above-mentioned eddy current sensor, the cable sheath is a stainless steel flexible tube.

[0018] Optionally, in the above-mentioned eddy current sensor, the cable is a coaxial cable.

[0019] As can be seen from the above scheme, the eddy current sensor disclosed in this application fixes the coil in the probe housing with high-temperature resistant epoxy resin, which makes the probe structure more stable and increases the probe's temperature resistance and stability. By setting up a shielding shell, external electromagnetic interference can be reduced and anti-interference ability can be improved, thereby improving measurement accuracy. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a top view of the eddy current sensor disclosed in an embodiment of this application;

[0022] Figure 2 This is a front view of the eddy current sensor disclosed in an embodiment of this application.

[0023] Among them, 10 is the probe, 11 is the coil, 12 is the probe housing, 13 is the shielding housing, and 131 is the locking nut;

[0024] 20 is the preamplifier, 21 is the preamplifier housing, 22 is the preamplifier cover, 23 is the circuit board, 24 is the RF connector socket, and 25 is the aviation socket.

[0025] 30 is the cable, and 31 is the RF connector plug;

[0026] 40 represents the cable sheath. Detailed Implementation

[0027] The core of this application is to disclose an eddy current sensor to improve measurement accuracy.

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] It should be noted that the eddy current sensor system operates on the principle of the eddy current effect. When the sensor system is powered on, a high-frequency signal is generated in the preamplifier 20. This signal is transmitted to the coil 11 via the cable 30, generating an alternating magnetic field H1 around the coil 11. When a conductive object approaches the coil 11, the alternating magnetic field induces eddy currents on the surface of the conductive object. If no metal conductor is nearby within the range of the magnetic field H1, the energy emitted into this range will be released. Conversely, if a metal conductor approaches the coil 11, the alternating magnetic field H1 will generate an eddy current field on the surface of the metal conductor. This eddy current field will also generate an alternating magnetic field H2 in the opposite direction to H1. Due to the reaction of the alternating magnetic field H2, the amplitude and phase of the high-frequency current in the coil 11 will change, thus changing the effective impedance of the coil 11. This change is related to both the eddy current effect and the magnetostatic effect, that is, to the conductivity, permeability, and geometry of the metal conductor, the geometric parameters of the coil 11, the excitation current frequency, and the distance parameters between the coil 11 and the metal conductor. If the material, winding method, and metal conductor of coil 11 are determined, then the impedance of coil 11 becomes a single-valued function of distance. The distance between coil 11 and the metal conductor can then be determined based on the impedance change of coil 11. The preamplifier 20 senses the change in parameters of coil 11 caused by the proximity of the metal conductor. After processing by the preamplifier 20, an output voltage or current signal is generated that linearly varies with the gap between the end face of probe 10 and the conductor being measured. The eddy current sensor in this application measures the high-expansion value by placing it on the high-expansion surface of the steam turbine, based on the above principle.

[0030] like Figure 1 and Figure 2 As shown in the figure, this application discloses an eddy current sensor, including a probe 10 and a preamplifier 20, which are electrically connected by a cable 30.

[0031] Specifically, the probe 10 includes a coil 11, a probe housing 12, and a shielding shell 13. The coil 11 is disposed within the probe housing 12, and the space between the coil 11 and the probe housing 12 is filled with high-temperature resistant epoxy resin to fix the coil 11. The probe housing 12 is disposed within the cavity of the shielding shell 13. The probe housing 12 is preferably made of a high-temperature resistant material, and the shielding shell 13 is preferably a metal shell, and preferably made of a corrosion-resistant and nuclear radiation-resistant material. The shielding shell 13 can prevent interference from the surrounding environment to the coil 11, thus providing a shielding effect. It should be noted that the space between the coil 11 and the probe housing 12 can also be filled with polyetheretherketone, ceramic-filled composite materials, etc., and is not limited to high-temperature resistant epoxy resin. Preferably, the coil 11 is made of a high-temperature resistant and low-temperature drift coefficient linear material; the shielding shell 13 is made of high-quality steel, which can protect the coil 11 and ensure reliable operation in harsh environments.

[0032] The eddy current sensor disclosed in this application uses high-temperature resistant epoxy resin to fix the coil 11 inside the probe housing 12, which makes the structure of the probe 10 more stable and increases the temperature resistance and stability of the probe 10. By setting the shielding shell 13, external electromagnetic interference can be reduced and the anti-interference ability can be improved, thereby improving the measurement accuracy.

[0033] Furthermore, in order to monitor the difference between the absolute expansion of the rotor and the high-pressure cylinder block and to better match the measured surface of the turbine, the probe 10 is rectangular in shape, that is, the shielding housing 13 is rectangular in shape. Typically, the high expansion measurement range of a megawatt-class nuclear power turbine is 30mm, and an eddy current sensor with a 50mm diameter circular probe is generally used to measure this 30mm high expansion. Since the high expansion measured surface of the turbine is a finite annular cross-section, a 50mm diameter circular probe cannot be installed. Therefore, this application changes the shape of the probe 10 to rectangular. The rectangular shape increases the measurement area along the length of the probe 10, matching the high expansion measured surface of the turbine and meeting the requirement of a 30mm high expansion measurement range, thereby improving the measurement sensitivity and accuracy of the high expansion measured surface of the turbine. Specifically, the coil 11 is preferably elliptical in shape, the probe housing 12 is preferably rectangular in shape, and the shielding housing 13 is preferably rectangular in shape.

[0034] Furthermore, such as Figure 1 and Figure 2As shown, the preamplifier 20 includes a preamplifier housing 21, a preamplifier cover 22, and a circuit board 23. The preamplifier cover 22 is detachably connected to the preamplifier housing 21, specifically by a snap-fit ​​connection or a bolt connection. The circuit board 23 is disposed in the cavity of the preamplifier housing 21 and integrates processing circuitry. Specifically, the circuit board 23 can be fixed inside the preamplifier housing 21 by a slot or by bolts. One end of the cable 30 is connected to the coil 11, and the other end is connected to the circuit board 23.

[0035] Furthermore, the preamplifier housing 21 is provided with an RF connector socket 24 that connects to the circuit board 23, and the cable 30 is provided with an RF connector plug 31 that can connect to the RF connector socket 24. The RF connector plug 31 and the RF connector socket 24 cooperate to improve the strength and stability of the connection.

[0036] Furthermore, an aviation socket 25 is provided on the preamplifier housing 21, which is connected to a data display that can display the value of the hyperextension measured by the eddy current sensor.

[0037] Furthermore, to enhance the structural rigidity and strength of the preamplifier housing 21, in some specific embodiments, the preamplifier housing 21 is integrally formed by casting or stamping. Of course, the preamplifier housing 21 can also be formed by multiple plates, with adjacent plates connected by welding, snap-fit ​​connection, or connectors; the specific connection method is not limited. The shielding housing 13 is preferably integrally formed.

[0038] Furthermore, a cable sheath 40 is provided on the outer side of the cable 30. The cable 30 passes through the cable sheath 40, through the shielding housing 13, and connects to the coil 11, preferably by welding. The cable sheath 40 and the shielding housing 13 can be detachably or non-detachably connected. Specifically, the cable sheath 40 can be welded to the shielding housing 13, and the shielding housing 13 has a through hole for the cable 30 to pass through. The cable 30 and the cable sheath 40 are encapsulated with high and low temperature resistant epoxy.

[0039] Furthermore, the shielding housing 13 is detachably connected to the cable sheath 40, as in some specific embodiments, such as... Figure 1 and Figure 2 As shown, a locking nut 131 is provided on the shielding housing 13, and an external thread that mates with the locking nut 131 is provided on the cable sheath 40. In some other embodiments, one of the shielding housing 13 and the cable sheath 40 is provided with a buckle, and the other is provided with a groove that mates with the buckle.

[0040] Furthermore, in order to accommodate the bending elongation of the cable 30, the cable sheath 40 is preferably made of stainless steel flexible tubing.

[0041] Furthermore, in order to improve anti-interference capability, cable 30 is preferably a high-temperature resistant coaxial cable, and cable 30 includes a center conductor and a metal shielding layer, which are coaxially arranged.

[0042] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0043] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0044] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

[0045] Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of the different embodiments or examples, without contradiction.

Claims

1. An eddy current sensor, characterized by, include: The probe (10) is rectangular in shape. The probe (10) includes a coil (11), a probe housing (12), and a shielding shell (13). The coil (11) is disposed inside the probe housing (12). High-temperature resistant epoxy resin is filled between the coil (11) and the probe housing (12). The probe housing (12) is disposed in the cavity of the shielding shell (13). The shielding shell (13) is rectangular in shape. The preamplifier (20) is electrically connected to the probe (10) via a cable (30).

2. The eddy current sensor of claim 1, wherein, The preamplifier (20) includes a preamplifier housing (21), a preamplifier cover (22), and a circuit board (23). The preamplifier cover (22) is detachably connected to the preamplifier housing (21). The circuit board (23) is disposed inside the preamplifier housing (21). One end of the cable (30) is connected to the coil (11), and the other end is connected to the circuit board (23).

3. The eddy current sensor of claim 2, wherein, The preamplifier housing (21) is provided with an RF connector socket (24) that is connected to the circuit board (23), and the cable (30) is provided with an RF connector plug (31) that is connected to the RF connector socket (24).

4. The eddy current sensor of claim 2, wherein, An aviation socket (25) is provided on the preamp housing (21), and the aviation socket (25) is connected to the data display.

5. The eddy current sensor of claim 2, wherein, The preamp housing (21) is integrally formed by casting or stamping.

6. The eddy current sensor of claim 1, wherein, The cable (30) is provided with a cable sheath (40) on the outside, and the cable sheath (40) is detachably or non-detachably connected to the shielding shell (13).

7. The eddy current sensor of claim 6, wherein, The cable sheath (40) is detachably connected to the shielding housing (13), the shielding housing (13) is provided with a locking nut (131), and the cable sheath (40) is provided with an external thread that mates with the locking nut (131); or, One of the shielding housing (13) and the cable sheath (40) is provided with a buckle, and the other is provided with a slot that cooperates with the buckle.

8. The eddy current sensor of claim 6, wherein, The cable sheath (40) is a stainless steel flexible tube.

9. An eddy current sensor as claimed in any one of claims 1 to 8, characterised in that, The cable (30) is a coaxial cable.

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