Eddy current sensor probe and eddy current sensor

Abstract

The present invention discloses an eddy current sensor probe and an eddy current sensor, wherein the eddy current sensor probe comprises a probe body, at least one protrusion and at least one position monitoring coil. The eddy current sensor comprises an eddy current sensor probe, a transmission shielding signal line and a preamplifier. The present invention arranges at least one evenly distributed protrusion at the rear end of the probe body of the eddy current sensor, and places the position monitoring coil and the peripheral circuit inside the protrusion accordingly, so as to measure the distance between the position monitoring coil and the outer shell of the monitored object, thereby realizing the eddy current sensor monitoring the position of its own probe, thereby ensuring that the probe is always in the correct position to monitor the equipment, thereby ensuring the accuracy of the eddy current sensor in monitoring the displacement of the equipment.

Description

Technical Field

[0001] The invention relates to the field of sensor devices, and in particular to an eddy current sensor probe and an eddy current sensor. Background Art

[0002] At present, power plants monitor the operating status of equipment mainly through sensors to monitor the temperature and vibration of equipment. Most vibration monitoring uses eddy current sensors, which monitor the vibration of objects by measuring displacement. In the complex environment of power plants, traditional eddy current sensors are very likely to produce errors without the knowledge of relevant personnel, thus causing the entire system to misjudge the status of the equipment.

[0003] In the prior art, eddy current sensors are generally installed by bonding or screwing, and both of these installation methods are prone to loosening or even falling off in the complex environment of a power plant.

[0004] When the sensor is loose, the displacement measured by the sensor changes, causing the system to make incorrect judgments about the operating status of the equipment. If the relevant personnel do not discover the looseness of the sensor in time, it may cause unnecessary downtime and affect production.

[0005] When the sensor falls off, the power plant system will alarm and the equipment is out of monitoring, which can easily lead to safety accidents. If it is important equipment, it will need to be shut down to reinstall the sensor, which will also have a major impact on production. Summary of the invention

[0006] The purpose of the present invention is to provide an eddy current sensor probe and an eddy current sensor, which can monitor the position of the probe itself and ensure that the probe is always in the correct position to monitor the equipment, thereby ensuring the accuracy of the equipment displacement monitoring.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] An eddy current sensor probe, the eddy current sensor probe comprising:

[0009] A probe body, the front end of which passes through the outer shell of the monitored object and extends into the interior of the monitored object, and is used to monitor the distance between the front end of the probe body and the inner core of the monitored object to obtain a device position monitoring signal;

[0010] at least one protrusion evenly distributed at the rear end of the probe body;

[0011] At least one position monitoring coil, used to monitor the distance between the position monitoring coil and the housing of the monitored object to obtain a corresponding relative position monitoring signal;

[0012] The number of the position monitoring coils is equal to the number of the protrusions; there is a gap inside the protrusion, which serves as a first gap; the first gap is used to store the position monitoring coils and peripheral circuits.

[0013] Optionally, the eddy current sensor probe further includes:

[0014] At least one support body is respectively embedded in the interior of the protrusions and is located between the position monitoring coil and the probe body, and is used to support and protect the position monitoring coil; the number of the support bodies is equal to that of the protrusions and corresponds one to one.

[0015] Optionally, the probe body comprises:

[0016] A front end housing, passing through the outer shell of the monitored object and extending into the interior of the monitored object;

[0017] A rear end housing connected to the front end housing and used to adjust the length of the front end housing extending into the interior of the monitored object; each of the protrusions is evenly distributed on the periphery of the rear end housing;

[0018] The device monitoring coil is located inside the front end housing and is used to monitor the distance between the device monitoring coil and the inner core of the monitored object to obtain a device position monitoring signal.

[0019] Optionally, there is a gap inside the front end shell, which serves as a second gap; the second gap is used to store the device monitoring coil and peripheral circuits.

[0020] Optionally, there is a gap inside the rear end shell, which serves as a third gap; and the third gap is respectively connected to the first gap and the second gap.

[0021] The present invention also provides an eddy current sensor, which comprises the above-mentioned eddy current sensor probe, a transmission shielding signal line and a preamplifier;

[0022] The transmission shielded signal line is connected to the equipment monitoring coil located in the probe body and the position monitoring coil located in the protrusion, respectively;

[0023] The preamplifier is connected to the transmission shielding signal line and is used to provide high-frequency oscillating current for generating eddy current effect to the device monitoring coil and the position monitoring coil respectively;

[0024] The preamplifier is also used to obtain the vibration displacement of the monitored object according to the equipment position monitoring signal and to determine whether the eddy current sensor probe is displaced according to the relative position monitoring signal.

[0025] Optionally, the eddy current sensor further includes a cable plug; the transmission shielding signal line is connected to the preamplifier via the cable plug.

[0026] Optionally, the transmission shielded signal line is composed of multiple coaxial cables; the number of the coaxial cables is equal to the total number of the device monitoring coils and the position monitoring coils; the multiple coaxial cables are respectively connected to the device monitoring coils, the position monitoring coils and the preamplifier.

[0027] Optionally, the preamplifier includes:

[0028] an oscillator, connected to the transmission shielded signal line, for providing a high-frequency oscillating current for generating an eddy current effect to the device monitoring coil and the position monitoring coil respectively;

[0029] The controller is connected to the transmission shielding signal line and is used to obtain the vibration displacement of the monitored object according to the equipment position monitoring signal and to determine whether the eddy current sensor probe is displaced according to the relative position monitoring signal.

[0030] Optionally, the eddy current sensor further includes:

[0031] An alarm is connected to the controller and is used to issue an alarm according to a prompt signal; the prompt signal is generated by the controller when the eddy current sensor probe is displaced.

[0032] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0033] The present invention provides an eddy current sensor probe and an eddy current sensor, wherein the eddy current sensor probe includes a probe body, at least one protrusion and at least one position monitoring coil. The eddy current sensor includes an eddy current sensor probe, a transmission shielding signal line and a preamplifier. The present invention provides at least one evenly distributed protrusion at the rear end of the probe body of the eddy current sensor, and places the position monitoring coil and the peripheral circuit inside the protrusion accordingly to measure the distance between the position monitoring coil and the outer shell of the monitored object, thereby realizing the eddy current sensor monitoring the position of its own probe, thereby ensuring that the probe is always in the correct position to monitor the equipment, thereby ensuring the accuracy of the eddy current sensor in monitoring the displacement of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0035] Figure 1 A perspective view of an eddy current sensor provided by the present invention;

[0036] Figure 2 A top view of an eddy current sensor probe provided by the present invention;

[0037] Figure 3 A schematic diagram of the working principle of an eddy current sensor provided by the present invention.

[0038] Explanation of symbols:

[0039] Equipment monitoring coil—1, front end shell—2, second gap—3, rear end shell—4, support body—5, first position monitoring coil—6, second position monitoring coil—7, third gap—8, transmission shielded signal line—9, cable plug—10. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The purpose of the present invention is to provide an eddy current sensor probe and an eddy current sensor, which can monitor the position of the probe itself and ensure that the probe is always in the correct position to monitor the equipment, thereby ensuring the accuracy of the equipment displacement monitoring.

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] According to Faraday's electromagnetic induction principle, when a bulk metal conductor is placed in a changing magnetic field or moves in a magnetic field to cut magnetic lines of force, a vortex-shaped induced current will be generated in the conductor. This current is called eddy current, and the above phenomenon is called eddy current effect. The sensor made based on the eddy current effect is called eddy current sensor.

[0044] The high-frequency oscillating current in the preamplifier of the eddy current sensor flows into the probe coil through the extension cable, generating an alternating magnetic field in the coil of the probe head. When the metal body to be measured is close to this magnetic field, an induced current is generated on the metal surface. At the same time, the eddy current field also generates an alternating magnetic field in the opposite direction to the magnetic field generated by the coil of the probe head. Due to its reaction, the amplitude and phase of the high-frequency current of the coil of the probe head are changed (that is, the effective impedance of the coil of the probe head is changed). This change is related to the parameters such as the magnetic permeability and electrical conductivity of the metal body, the geometric shape and geometric dimensions of the coil, the current frequency, and the distance from the coil of the probe head to the surface of the metal conductor. It is usually assumed that the material of the metal conductor is uniform and the performance is linear and isotropic. The physical properties of the coil and the metal conductor system can be described by the electrical conductivity б, magnetic permeability ξ, size factor τ, the distance D between the coil of the probe head and the surface of the metal conductor, the current intensity I and the frequency ω parameters of the metal conductor. The characteristic impedance of the coil can be represented by the function Z=F(τ,ξ,б,D,I,ω).

[0045] Usually we can control the parameters τ, ξ, б, I, ω to remain unchanged within a certain range, then the characteristic impedance Z of the coil becomes a single-valued function of the distance D. Although the entire function is nonlinear and its function characteristic is an "S" curve, we can select a section that is approximately linear. At the same time, through the processing of the electronic circuit in the preamplifier, the change of the coil impedance Z (that is, the change of the distance D between the head body coil and the metal conductor) can be converted into a voltage or current signal output, and the size of the output signal varies with the distance between the probe and the surface of the measured object. The eddy current sensor is based on this principle to measure the displacement, vibration and other parameters of metal objects.

[0046] When the distance between the metal being measured and the probe changes, the Q value of the coil in the probe also changes. The change in Q value causes the change in the amplitude of the oscillating voltage. This oscillating voltage that changes with distance is transformed into a voltage (or current) change through detection, filtering, linear compensation, and amplification and normalization. Finally, the distance (i.e., the gap between the front end of the probe and the surface of the metal being measured) is converted into a voltage (or current), thereby realizing the measurement of the vibration displacement of the metal being measured. As mentioned above, the object being measured in the working system of the eddy current sensor can be regarded as half of the sensor system, that is, the performance of an eddy current displacement sensor is related to the object being measured.

[0047] Embodiment 1 is the specific setting of an eddy current sensor probe provided by the present invention; Embodiment 2 is the specific setting of an eddy current sensor provided by the present invention; Embodiment 3 is the working principle of an eddy current sensor provided by the present invention.

[0048] Example 1

[0049] Figure 1A perspective view of an eddy current sensor provided by the present invention, such as Figure 1 As shown, the eddy current sensor probe provided by the present invention includes a probe body (including Figure 1 1, 2, 3 and 4), at least one protrusion and at least one position monitoring coil (including Figure 1 6 and 7).

[0050] Specifically, the front end of the probe body passes through the outer shell of the monitored object and extends into the interior of the monitored object; the probe body is used to monitor the distance between the front end of the probe body and the inner core of the monitored object to obtain a device position monitoring signal.

[0051] The at least one protrusion is evenly distributed at the rear end of the probe body.

[0052] The at least one position monitoring coil is used to monitor the distance between the position monitoring coil and the outer shell of the monitored object to obtain a corresponding relative position monitoring signal.

[0053] In addition, the number of the position monitoring coils is equal to the number of the protrusions and corresponds one to one; there is a gap inside the protrusion, which serves as a first gap; the first gap is used to store the position monitoring coil and peripheral circuits.

[0054] Among them, the working principles of the probe body monitoring the distance between it and the inner core of the monitored object to obtain the equipment position monitoring signal and the position monitoring coil monitoring the distance between it and the outer shell of the monitored object to obtain the relative position monitoring signal are both the above-mentioned eddy current effect.

[0055] Furthermore, the eddy current sensor probe also includes at least one support body 5, which is respectively embedded in the interior of the protrusion and located between the position monitoring coil and the probe body, and is used to support and protect the position monitoring coil; the number of the support bodies 5 is equal to that of the protrusion and corresponds one to one.

[0056] Furthermore, the probe body includes a front end shell 2 , a rear end shell 4 and a device monitoring coil 1 .

[0057] Specifically, the front end housing 2 passes through the outer shell of the monitored object and extends into the interior of the monitored object. The rear end housing 4 is connected to the front end housing 2 and is used to adjust the length of the front end housing 2 extending into the interior of the monitored object; each of the protrusions is evenly distributed on the periphery of the rear end housing 4. The device monitoring coil 1 is located inside the front end housing 2 and is used to monitor the distance between the device monitoring coil 1 and the inner core of the monitored object to obtain a device position monitoring signal.

[0058] Figure 2A top view of an eddy current sensor probe provided by the present invention, such as Figure 1 and 2 As shown, the front end housing 2 and the rear end housing 4 are both cylindrical; and the outer diameters of the front end housing 2 and the rear end housing 4 are equal.

[0059] In this embodiment, the number of the protrusion, the support and the position monitoring coil are two respectively; and the shape of the protrusion and the support are both rectangular; the two position monitoring coils are respectively called the first position monitoring coil 6 and the second position monitoring coil 7. However, this is not a limitation and can be adjusted according to the actual situation such as the shape and size of the monitored object.

[0060] As a specific implementation of this embodiment, the surface of the rear end shell 4 is covered with threads; the eddy current sensor probe adjusts the length of the front end shell 2 extending into the interior of the monitored object through the threads, and fixes the front end shell 2 at a set position.

[0061] Preferably, the front end shell 2 is connected to the rear end shell 4 in a concave-convex manner; the tail of the front end shell 2 protrudes outward, and the head of the rear end shell 4 is concave inward at the position where it connects with the front end shell 2, and the two are interlocked for fixation.

[0062] Preferably, there is a gap inside the front end housing 2, serving as a second gap 3; the second gap 3 is used to store the device monitoring coil 1 and peripheral circuits.

[0063] Preferably, there is a gap inside the rear end housing 4, which serves as a third gap 8; the third gap 8 is connected to the first gap and the second gap 2 respectively.

[0064] Example 2

[0065] like Figure 1 As shown, the eddy current sensor provided by the present invention includes the above-mentioned eddy current sensor probe, a transmission shielded signal line 9 and a preamplifier.

[0066] Specifically, the transmission shield signal line 9 is respectively connected to the device monitoring coil 1 located in the probe body and the position monitoring coil (including Figure 1 6 and 7) are connected.

[0067] The preamplifier is connected to the transmission shield signal line 9, and is used to provide high-frequency oscillating current for generating eddy current effect to the equipment monitoring coil 1 and the position monitoring coil. The preamplifier is also used to obtain the vibration displacement of the monitored object according to the equipment position monitoring signal and to determine whether the eddy current sensor probe is displaced according to the relative position monitoring signal.

[0068] Furthermore, the eddy current sensor also includes a cable plug 10 ; the transmission shielded signal line 9 is connected to the preamplifier through the cable plug 10 .

[0069] As a specific implementation of this embodiment, the transmission shielded signal line 9 is composed of multiple coaxial cables; the number of the coaxial cables is equal to the total number of the device monitoring coil 1 and the position monitoring coil; the multiple coaxial cables are respectively connected to the device monitoring coil 1, the position monitoring coil and the preamplifier.

[0070] Furthermore, the preamplifier includes an oscillator and a controller.

[0071] Specifically, the oscillator is connected to the transmission shielding signal line 9, and is used to provide high-frequency oscillating current for generating eddy current effect to the device monitoring coil 1 and the position monitoring coil respectively; the controller is connected to the transmission shielding signal line, and is used to obtain the vibration displacement of the monitored object according to the device position monitoring signal and to determine whether the eddy current sensor probe is displaced according to the relative position monitoring signal.

[0072] Preferably, the oscillator is a crystal oscillator; the controller is an STC single-chip microcomputer, an STM32 single-chip microcomputer or a data acquisition card, but it is not limited thereto and can be adjusted according to actual needs.

[0073] Furthermore, the eddy current sensor also includes an alarm; the alarm is connected to the controller and is used to issue an alarm according to a prompt signal; the prompt signal is generated by the controller when the eddy current sensor probe is displaced.

[0074] Preferably, the alarm is a horn, an indicator light, etc.

[0075] Taking the number of position monitoring coils of the eddy current sensor probe provided by the present invention as two as an example, Figure 3 A schematic diagram of the working principle of an eddy current sensor provided by the present invention is shown in FIG. Figure 3 As shown, the usage steps and specific working principle of the eddy current sensor are as follows:

[0076] 1) When the equipment to be monitored is in a stopped state, first grind the position where the equipment needs to be monitored to ensure that the position is flat and tidy, then drill a hole, insert the front end shell 2 of the eddy current sensor probe inward, and use the thread on the rear end shell 4 of the eddy current sensor probe to adjust the position and fix it.

[0077] 2) After the eddy current sensor probe is completely fixed and the device is in a stationary state, the position monitoring coil 6 measures the distance d1 from the surface of the device to be monitored, obtains the first initial voltage V1 and records it; the position monitoring coil 7 measures the distance d2 from the surface of the device to be monitored, obtains the second initial voltage V2 and records it.

[0078] 3) When the equipment starts running, the equipment monitoring coil 1 starts to measure the vibration displacement of the equipment to be monitored. At the same time, the first position monitoring coil and the second position monitoring coil continue to measure their respective distances to the surface of the equipment to be monitored, and obtain the corresponding voltages v1 and v2 respectively, and transmit the collected voltages to the controller through the peripheral circuit and the transmission shielded signal line for processing.

[0079] 4) The controller compares the voltages v1 and v2 collected when the equipment is running with the initial voltages V1 and V2 respectively. If v1-V1=0 and v2-V2=0, it means that the distances d1 and d2 from the first position monitoring coil 6 and the second position monitoring coil 7 to the equipment surface have not changed, and the eddy current sensor probe has not moved. At this time, the data collected by the equipment monitoring coil is normal; if v1-V1≠0 or v2-V2≠0, it means that the distances d1 or d2 from the first position monitoring coil 6 and the second position monitoring coil 7 to the equipment surface have changed, and the eddy current sensor probe has moved, that is, it is loose. At this time, the eddy current sensor does not measure the actual displacement of the equipment, and the controller will generate a prompt signal, indicating that personnel are required to go to the site for processing.

[0080] Compared with the prior art, the sensor provided by the present invention can ensure that the probe is always in the correct position to monitor the equipment through its own self-monitoring, thereby ensuring the accuracy of the monitoring value. After the eddy current sensor probe is displaced, the measured data often deviates. If the system does not prompt, it is easy to produce wrong results, causing technicians to make wrong judgments, thereby affecting production. When the eddy current sensor provided by the present invention is displaced or deviated, it can promptly prompt the technician to re-fix the eddy current sensor probe or record it, thereby avoiding affecting production.

[0081] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0082] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An eddy current sensor probe, characterized in that: The eddy current sensor probe comprises: A probe body, the front end of which passes through the outer shell of the monitored object and extends into the interior of the monitored object, and is used to monitor the distance between the front end of the probe body and the inner core of the monitored object to obtain a device position monitoring signal; at least one protrusion evenly distributed at the rear end of the probe body; At least one position monitoring coil, used to monitor the distance between the position monitoring coil and the housing of the monitored object to obtain a corresponding relative position monitoring signal; The number of the position monitoring coils is equal to the number of the protrusions; there is a gap inside the protrusion, which serves as a first gap; the first gap is used to store the position monitoring coils and peripheral circuits.

2. The eddy current sensor probe according to claim 1, characterized in that: The eddy current sensor probe also includes: At least one support body is respectively embedded in the interior of the protrusions and is located between the position monitoring coil and the probe body, and is used to support and protect the position monitoring coil; the number of the support bodies is equal to that of the protrusions and corresponds one to one.

3. The eddy current sensor probe according to claim 1, characterized in that: The probe body comprises: A front end housing, passing through the outer shell of the monitored object and extending into the interior of the monitored object; A rear end housing connected to the front end housing and used to adjust the length of the front end housing extending into the interior of the monitored object; each of the protrusions is evenly distributed on the periphery of the rear end housing; The device monitoring coil is located inside the front end housing and is used to monitor the distance between the device monitoring coil and the inner core of the monitored object to obtain a device position monitoring signal.

4. The eddy current sensor probe according to claim 3, characterized in that: There is a gap inside the front end shell, which serves as a second gap; the second gap is used to store the equipment monitoring coil and peripheral circuits.

5. The eddy current sensor probe according to claim 4, characterized in that: A gap exists inside the rear end housing, serving as a third gap; the third gap is communicated with the first gap and the second gap respectively.

6. An eddy current sensor, characterized in that: The eddy current sensor comprises an eddy current sensor probe as claimed in any one of claims 1 to 5, a transmission shielded signal line and a preamplifier; The transmission shielded signal line is connected to the equipment monitoring coil located in the probe body and the position monitoring coil located in the protrusion, respectively; The preamplifier is connected to the transmission shielding signal line and is used to provide high-frequency oscillating current for generating eddy current effect to the device monitoring coil and the position monitoring coil respectively; The preamplifier is also used to obtain the vibration displacement of the monitored object according to the equipment position monitoring signal and to determine whether the eddy current sensor probe is displaced according to the relative position monitoring signal.

7. The eddy current sensor according to claim 6, characterized in that: The eddy current sensor also includes a cable plug; the transmission shielding signal line is connected to the preamplifier through the cable plug.

8. The eddy current sensor according to claim 6, characterized in that: The transmission shielded signal line is composed of multiple coaxial cables; the number of the coaxial cables is equal to the total number of the device monitoring coils and the position monitoring coils; the multiple coaxial cables are respectively connected to the device monitoring coils, the position monitoring coils and the preamplifier.

9. The eddy current sensor according to claim 6, characterized in that: The preamplifier comprises: an oscillator, connected to the transmission shielded signal line, for providing a high-frequency oscillating current for generating an eddy current effect to the device monitoring coil and the position monitoring coil respectively; The controller is connected to the transmission shielding signal line and is used to obtain the vibration displacement of the monitored object according to the equipment position monitoring signal and to determine whether the eddy current sensor probe is displaced according to the relative position monitoring signal.

10. The eddy current sensor according to claim 9, characterized in that: The eddy current sensor also includes: An alarm is connected to the controller and is used to issue an alarm according to a prompt signal; the prompt signal is generated by the controller when the eddy current sensor probe is displaced.

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