Pressure Sensor and Detection System for Pressure Sensor

Abstract

The present disclosure provides a pressure sensor and a detection system for the pressure sensor, belonging to the technical field of pressure measurement. The pressure sensor includes a pressure-receiving component, an optical fiber grating component, and a housing. The pressure-receiving component includes a pressure plate, a force transmission rod, and a shock-absorbing device. The first end of the force transmission rod is connected to one side of the pressure plate, and the shock-absorbing device is connected to the middle of the force transmission rod. The optical fiber grating component includes a first optical fiber grating, an induction ball, and a first optical fiber. The first optical fiber grating is connected in series with the first optical fiber, and the first optical fiber is in contact with the outer wall of the induction ball. The pressure plate is located outside the housing, and the force transmission rod and the shock-absorbing device are both located inside the housing. The optical fiber grating component is located inside the housing. The present disclosure can improve the detection accuracy of the pressure sensor through the pressure sensor.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of pressure measurement, and particularly relates to a pressure sensor and a detection system for the pressure sensor. Background Art

[0002] As one of the most important types of sensors, pressure sensors are widely used in various industrial automation environments. Such as water conservancy and hydropower, railway transportation, intelligent buildings, production automation, aerospace, military, petrochemical, oil wells, electric power, ships, machine tools, pipelines, etc.

[0003] In related technologies, pressure sensors are generally electromagnetic pressure sensors. An electromagnetic pressure sensor generally includes a force-receiving element (which can be made of metal or semiconductor materials, for example). That is, an electromagnetic pressure sensor is a sensor that indirectly measures pressure by measuring the strain of the force-receiving element. When the force-receiving element is subjected to pressure, its length and cross-sectional area will both change. Correspondingly, the resistance value will change. In this way, the change value of the resistance value can be obtained to inversely deduce the strain of the force-receiving element, and finally the pressure to be measured can be obtained.

[0004] However, since electromagnetic signals are required when using an electromagnetic pressure sensor, it is easily affected by electromagnetic signal interference, reducing the detection accuracy, and the wiring method is complex, making it inconvenient to use. Summary of the Invention

[0005] Embodiments of the present disclosure provide a pressure sensor and a detection system for the pressure sensor, which can improve the detection accuracy of the pressure sensor. The technical solution is as follows:

[0006] Embodiments of the present disclosure provide a pressure sensor, which includes a pressure-receiving component, a fiber Bragg grating component, and a housing. The pressure-receiving component includes a pressure plate, a force-transmitting rod, and a shock-absorbing device. The first end of the force-transmitting rod is connected to one side of the pressure plate, and the shock-absorbing device is connected to the middle of the force-transmitting rod; the fiber Bragg grating component includes a first fiber Bragg grating, an induction ball, and a first optical fiber. The first fiber Bragg grating is connected in series with the first optical fiber. The first optical fiber is attached to the outer wall of the induction ball. The length direction of the first optical fiber is perpendicular to the axis direction of the force-transmitting rod. The first side of the induction ball is connected to the second end of the force-transmitting rod. Along the axis direction of the force-transmitting rod, the second side of the induction ball and the first side of the induction ball are respectively located on both sides of the center point of the induction ball. The first optical fiber is located between the center point of the induction ball and the second side; the pressure plate is located outside the housing, and both the force-transmitting rod and the shock-absorbing device are located inside the housing; the fiber Bragg grating component is located inside the housing.

[0007] In another implementation of the present disclosure, the fiber grating assembly further includes a second fiber grating and a second optical fiber. The second fiber grating is connected in series with the second optical fiber. The second optical fiber is attached to the outer wall of the sensing sphere. The first optical fiber and the second optical fiber are parallel to each other. In the axial direction of the force transmission rod, the first optical fiber and the second optical fiber are respectively located on both sides of the center point of the sensing sphere.

[0008] In another implementation of the present disclosure, the sensing sphere is an ellipsoid, and the major axis direction of the sensing sphere is the same as the axial direction of the force transmission rod.

[0009] In another implementation of the present disclosure, the shock absorption device includes a first connecting member, a second connecting member, and an elastic telescopic rod. The first connecting member is connected to the middle part of the force transmission rod. The second connecting member is slidably connected to the middle part of the force transmission rod. The second connecting member is connected to the inner wall of the housing. The first connecting member and the second connecting member are arranged at intervals. The elastic telescopic rod is located between the first connecting member and the second connecting member. Two ends of the elastic telescopic rod are respectively hinged to the first connecting member and the second connecting member.

[0010] In another implementation of the present disclosure, there are two elastic telescopic rods, and the two elastic telescopic rods are symmetrically arranged with the axis of the force transmission rod as the axis of symmetry. An included angle is formed between the elastic telescopic rod and the force transmission rod. The distance between the first end of the elastic telescopic rod and the force transmission rod is less than the distance between the second end of the elastic telescopic rod and the force transmission rod. The first end of the elastic telescopic rod faces the end of the first connecting member, and the second end of the elastic telescopic rod faces the end of the second connecting member. The first connecting member is located between the second connecting member and the pressure plate.

[0011] In another implementation of the present disclosure, the elastic telescopic rod includes a telescopic cylinder, an elastic telescopic member, and a connecting rod. The elastic telescopic member is movably located in the telescopic cylinder along the axis of the telescopic cylinder. The first end of the elastic telescopic member is connected to the inner wall of the telescopic cylinder. The second end of the elastic telescopic member is connected to the first end of the connecting rod. The telescopic cylinder is hinged to the second connecting member, and the second end of the connecting rod is connected to the first connecting member.

[0012] In another implementation of the present disclosure, the fiber grating assembly further includes at least a pair of fixed supports. Along the direction perpendicular to the axis of the force transmission rod, the at least a pair of fixed supports are respectively located on opposite sides of the sensing sphere, and the first optical fiber is fixedly connected to the at least a pair of fixed supports respectively.

[0013] In another implementation of the present disclosure, the fixed support includes an outer sleeve and a core tube. The core tube is located inside the outer sleeve, and both ends of the core tube are respectively connected to the outer sleeve; the core tube is sleeved outside the first optical fiber.

[0014] In another implementation of the present disclosure, the sensing ball is a soft rubber structural member.

[0015] In another implementation of the present disclosure, a detection system for a pressure sensor is further provided. The detection system includes a pressure sensor and a demodulator; the pressure sensor is the pressure sensor described above, and the demodulator is connected to both ends of the first optical fiber.

[0016] The beneficial effects brought by the technical solution provided by the embodiments of the present disclosure are as follows:

[0017] When the pressure sensor provided by the embodiments of the present disclosure detects the pressure sensed by the object to be measured, since the pressure sensor includes a pressure-receiving component and a fiber grating component, and the pressure-receiving component includes a pressure plate, a force-transmitting rod, and a shock-absorbing device, the pressure plate can be connected to the object to be measured to transmit the received pressure through the pressure plate. At the same time, the pressure received by the pressure plate is transmitted to the sensing ball through the force-transmitting rod, and the shock-absorbing device is used for buffering to slow down the acting force received by the force-transmitting rod, thereby reducing the pressure received by the sensing ball.

[0018] Since the first optical fiber abuts against the outer wall of the sensing ball, and the first optical fiber is located between the center point of the sensing ball and the second side, when the sensing ball moves downward under pressure, the first optical fiber will be pressured by the sensing ball, so that the first fiber grating connected to the first optical fiber is axially pressured and deformed, thereby changing the original central wavelength of the first fiber grating. Thus, the pressure can be detected according to the wavelength drift of the first fiber grating, eliminating the influence of the environment and the like on the detection process, greatly improving the detection accuracy and simplifying the detection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 is a schematic structural diagram of the pressure sensor provided by the embodiments of the present disclosure.

[0021] The meanings represented by the symbols in the figure are as follows:

[0022] 1. Compression assembly; 11. Pressure plate; 12. Force transmission rod; 13. Shock absorption device; 131. First connecting piece; 132. Second connecting piece; 133. Elastic telescopic rod; 1331. Telescopic cylinder; 1332. Elastic telescopic piece; 1333. Connecting rod;

[0023] 2. Fiber Bragg grating assembly; 21. First fiber Bragg grating; 22. Induction ball; 23. First optical fiber; 24. Second fiber Bragg grating; 25. Second optical fiber; 26. Fixed support; 261. Outer sleeve; 262. Core tube;

[0024] 3. Outer shell. Specific embodiments

[0025] To make the objectives, technical solutions and advantages of the present disclosure clearer, the following will further describe the embodiments of the present disclosure in detail with reference to the accompanying drawings.

[0026] To clearly illustrate the pressure sensor provided by the embodiments of the present disclosure, the detection principle of the fiber Bragg grating sensor will be briefly described first.

[0027] The fiber Bragg grating sensor is a fiber sensing technology based on the reflected light wavelength information, and its sensing unit is the fiber Bragg grating. The physical quantity measured by the fiber Bragg grating sensor depends not only on the demodulator of the fiber Bragg grating, but more on the fiber Bragg grating.

[0028] During detection, the fiber Bragg grating is connected to the demodulator through an optical fiber. When the broadband light emitted by the demodulator passes through the fiber Bragg grating, the fiber Bragg grating will reflect a narrowband light with a certain central wavelength (the wavelength of this narrowband light depends on the grating pitch of the fiber Bragg grating. Its mathematical expression is: λ = 2nΛ, where λ is the central wavelength of the narrowband light reflected back by the fiber Bragg grating; n is the effective refractive index of the fiber core; Λ is the grating pitch. When the strain sensed by the fiber Bragg grating changes, the grating pitch will change, that is, the central wavelength of the reflected narrowband light (i.e., the reflection central wavelength) will shift relative to the original central wavelength (the so-called original central wavelength is the central wavelength of the narrowband light reflected back by the fiber Bragg grating when it does not sense strain), and the measured strain value can be obtained by demodulating the reflected narrowband light.

[0029] Among them, the demodulator integrates a light source, an optical fiber coupler, a light detection module, a signal demodulation module, a data processing module, etc. The demodulator can be directly connected to a computer. In this way, by reading the wavelength drift amount of the fiber Bragg grating on the computer, the measured strain value can be obtained.

[0030] The embodiments of the present disclosure provide a pressure sensor, as Figure 1As shown in the figure, the pressure sensor includes a pressure-receiving component 1, a fiber Bragg grating component 2, and a housing 3. The pressure-receiving component 1 includes a pressure plate 11, a force-transmitting rod 12, and a shock-absorbing device 13. The first end of the force-transmitting rod 12 is connected to one side of the pressure plate 11, and the shock-absorbing device 13 is connected to the middle of the force-transmitting rod 12.

[0031] The fiber Bragg grating component 2 includes a first fiber Bragg grating 21, an induction ball 22, and a first optical fiber 23. The first fiber Bragg grating 21 is connected in series with the first optical fiber 23. The first optical fiber 23 is attached to the outer wall of the induction ball 22. The length direction of the first optical fiber 23 is perpendicular to the axis direction of the force-transmitting rod 12. The first side of the induction ball 22 is connected to the second end of the force-transmitting rod 12. Along the axis direction of the force-transmitting rod 12, the second side of the induction ball 22 and the first side of the induction ball 22 are respectively located on both sides of the center point of the induction ball 22. The first optical fiber 23 is located between the center point of the induction ball 22 and the second side.

[0032] The pressure plate 11 is located outside the housing 3, and both the force-transmitting rod 12 and the shock-absorbing device 13 are located inside the housing 3. The fiber Bragg grating component 2 is located inside the housing 3.

[0033] When the pressure sensor provided by the embodiment of the present disclosure detects the pressure sensed by the object to be measured, since the pressure sensor includes a pressure-receiving component 1 and a fiber Bragg grating component 2, and the pressure-receiving component 1 includes a pressure plate 11, a force-transmitting rod 12, and a shock-absorbing device 13, the pressure plate 11 can be connected to the object to be measured to transmit the received pressure through the pressure plate 11. At the same time, generally, the force-transmitting rod 12 transmits the pressure received by the pressure plate 11 to the induction ball 22, and the shock-absorbing device 13 buffers to slow down the acting force received by the force-transmitting rod 12, and finally reduces the pressure received by the induction ball 22.

[0034] Since the first fiber Bragg grating 21 abuts against the outer wall of the induction ball 22, and the first optical fiber 23 is located between the center point of the induction ball 22 and the second side, when the induction ball 22 moves downward under pressure, the first optical fiber 23 will be subjected to the pressure of the induction ball 22, so that the first fiber Bragg grating 21 connected to the first optical fiber 23 is subjected to axial pressure and deforms, thereby changing the original central wavelength of the first fiber Bragg grating 21. Thus, the pressure can be detected according to the wavelength drift amount of the first fiber Bragg grating 21, eliminating the influence of electromagnetic signals in the environment on the detection process, greatly improving the detection accuracy and simplifying the detection process.

[0035] In addition, the housing 3, as the sealing and protecting structure of the pressure sensor, can not only isolate the influence of the external environment, but also protect the components inside the housing 3, so as to improve the service life of the pressure sensor.

[0036] Exemplarily, the fiber grating assembly 2 further includes a second fiber grating 24 and a second optical fiber 25. The second fiber grating 24 is connected in series with the second optical fiber 25. The second optical fiber 25 is attached to the outer wall of the sensing sphere 22. The first optical fiber 23 and the second optical fiber 25 are parallel to each other. In the axial direction of the force transmission rod 12, the first optical fiber 23 and the second optical fiber 25 are respectively located on both sides of the center point of the sensing sphere 22.

[0037] In the above implementation, the first fiber grating 21 and the second fiber grating 24 are arranged. One of them can be used as the main element for pressure detection, and the other as temperature compensation. Thus, when detecting pressure, the influence of the ambient temperature on the detection process can be eliminated, greatly improving the detection accuracy.

[0038] For example, during detection, when the sensing sphere 22 moves downward under the pressure of the force transmission rod 12, since the second optical fiber 25 is located above the center point of the sensing sphere 22 ( Figure 1 above as shown in Figure 1 , that is, between the center point of the sensing sphere 22 and the first side). The first optical fiber 23 is located below the center point of the sensing sphere 22 (

[0039] below as shown in

[0040] , that is, between the center point of the sensing sphere 22 and the second side), so when the sensing sphere 22 moves downward, it will slide relative to the second optical fiber 25, causing the second optical fiber 25 to change from being in contact with the larger outer diameter of the sensing sphere 22 to being spaced from the smaller outer diameter of the sensing sphere 22. On the contrary, for the first optical fiber 23, it changes from being in contact with the smaller outer diameter of the sensing sphere 22 to being in contact with the larger outer diameter of the sensing sphere 22. In this way, since the second optical fiber 25 is not subjected to the pressure of the sensing sphere 22, the second fiber grating 24 connected to the second optical fiber 25 will not be axially strained to cause a shift in the central wavelength. However, since the first optical fiber 23 is subjected to the pressure of the sensing sphere 22, the first fiber grating 21 connected to the first optical fiber 23 will be axially strained to cause a shift in the central wavelength.

[0039] In addition, since the first fiber grating 21 and the second fiber grating 24 are in the same environment, the detection results of both the first fiber grating 21 and the second fiber grating 24 include the detection results of the original central wavelength changing due to the change in the ambient temperature. Thus, by taking the difference between the detection results of the first fiber grating 21 and the second fiber grating 24, the influence of temperature can be eliminated. That is, by taking the difference between the wavelength drift amounts of the first fiber grating 21 and the second fiber grating 24 through the self-differential compensation method, the effect of sensor temperature self-compensation can be achieved.

[0040] In actual use, the first fiber Bragg grating 21 and the second fiber Bragg grating 24 can be connected in series with each other through the first optical fiber 23 and the second optical fiber 25 and connected to the same demodulator, which can simplify the structure. Of course, the first fiber Bragg grating 21 and the second fiber Bragg grating 24 can also be respectively connected to a demodulator.

[0041] The reflection center wavelengths of the first fiber Bragg grating 21 and the second fiber Bragg grating 24 are different, and the initial center wavelengths of the first fiber Bragg grating 21 and the second fiber Bragg grating 24 are the same.

[0042] In the above implementation, since the initial center wavelengths of the first fiber Bragg grating 21 and the second fiber Bragg grating 24 are the same, when the first fiber Bragg grating 21 and the second fiber Bragg grating 24 are detected, the wavelength drift amounts of the first fiber Bragg grating 21 and the second fiber Bragg grating 24 are the same due to the influence of temperature. By setting the reflection center wavelengths of the first fiber Bragg grating 21 and the second fiber Bragg grating 24 to be different, when the first fiber Bragg grating 21 and the second fiber Bragg grating 24 are connected in series to the same demodulator, the demodulator can distinguish the emission signals of different fiber Bragg gratings according to different reflection center wavelengths.

[0043] Optionally, the sensing ball 22 is an ellipsoid, and the major axis direction of the sensing ball 22 is the same as the axis direction of the force transmission rod 12.

[0044] In the above implementation, the sensing ball 22 is set as an ellipsoid, and the major axis direction of the sensing ball 22 is the same as the axis direction of the force transmission rod 12. In this way, compared with a spherical ball, the ellipsoid setting can increase the movable stroke of the sensing ball 22 on the premise that the outer diameter change amount of the sensing ball 22 is the same, thereby improving the detection range of the pressure sensor.

[0045] Optionally, the sensing ball 22 is a soft rubber structural member.

[0046] Setting the sensing ball 22 as a soft rubber structural member can, on the one hand, reduce the weight of the pressure sensor, and on the other hand, can also slow down the pressure acting on the first optical fiber 23 or the second optical fiber 25, avoiding the phenomenon that the first optical fiber 23 or the second optical fiber 25 breaks due to excessive pressure.

[0047] Optionally, the fiber Bragg grating assembly 2 further includes at least a pair of fixed supports 26. Along the direction perpendicular to the axis of the force transmission rod 12, at least a pair of fixed supports 26 are respectively located on the opposite sides of the sensing ball 22, and the first optical fiber 23 is fixedly connected to at least a pair of fixed supports 26 respectively.

[0048] In the above implementation, the fixed support 26 is used to fix both ends of the first optical fiber 23, so that after the first optical fiber 23 is connected to the first fiber grating 21, it can be well attached to the outer wall of the sensing sphere 22.

[0049] Exemplarily, there can be two pairs of fixed supports 26. One pair of fixed supports 26 is correspondingly connected to the first optical fiber 23. The other pair is correspondingly connected to the second optical fiber 25. Each pair of fixed supports 26 is respectively located on both sides of the sensing sphere 22 in the long axis direction.

[0050] In this way, the first optical fiber 23 and the second optical fiber 25 can be effectively attached to the outer wall of the sensing sphere 22.

[0051] Optionally, the fixed support 26 includes an outer sleeve 261 and a core tube 262. The core tube 262 is located inside the outer sleeve 261, and both ends of the core tube 262 are respectively connected to the outer sleeve 261. The core tube 262 is sleeved outside the first optical fiber 23 or the second optical fiber 25.

[0052] In the above implementation, the core tube 262 is used to connect to the first optical fiber 23 or the second optical fiber 25, and the outer sleeve 261 is used to protect the core tube 262.

[0053] Exemplarily, the core tube 262 is connected to the outer wall of the first optical fiber 23 or the second optical fiber 25 by pasting. This can facilitate the connection and fixation of the first optical fiber 23 or the second optical fiber 25.

[0054] Exemplarily, the core tube 262 can be a glass fiber tube. At this time, it can be pasted to the first optical fiber 23 or the second optical fiber 25 through epoxy resin glue.

[0055] The outer sleeve 261 can be a metal structural member. This can improve the structural strength of the fixed support 26, and thus effectively protect the core tube 262 to extend the service life of the fixed support 26.

[0056] Continuing to refer to Figure 1 , optionally, the shock absorption device 13 includes a first connecting member 131, a second connecting member 132, and an elastic telescopic rod 133.

[0057] The first connecting member 131 is connected to the middle of the force transmission rod 12. The second connecting member 132 is slidably connected to the middle of the force transmission rod 12, and the first connecting member 131 and the second connecting member 132 are arranged at intervals from each other. The elastic telescopic rod 133 is located between the first connecting member 131 and the second connecting member 132, and both ends of the elastic telescopic rod 133 are respectively hinged to the first connecting member 131 and the second connecting member 132. The elastic telescopic rod 133 is used to expand and contract along its own axis.

[0058] In the above implementation, the first connecting member 131 is used to connect with the force transmission rod 12 to share the pressure received by the force transmission rod 12. The elastic telescopic rod 133 is used to connect the first connecting member 131 and the second connecting member 132, so as to absorb the pressure received by the first connecting member 131 through its own telescopic change, thereby reducing the acting force exerted by the force transmission rod 12 on the induction ball 22 and reducing the moving range of the induction ball 22.

[0059] In this embodiment, the hinge axis between the elastic telescopic rod 133 and the first connecting member 131 and the second connecting member 132 is perpendicularly arranged to the elastic telescopic rod 133. In this way, the connection angle between the elastic telescopic rod 133 and the first connecting member 131 and the second connecting member 132 can be flexibly adjusted by means of hinge, so as to facilitate the elastic telescopic rod 133 to always be well connected with the first connecting member 131 and the second connecting member 132 during the telescopic movement.

[0060] Optionally, there may be two elastic telescopic rods 133, and the two elastic telescopic rods 133 are symmetrically arranged with the axis of the force transmission rod 12 as the symmetry axis. An angle is formed between the elastic telescopic rod 133 and the force transmission rod 12, and the distance between the first end of the elastic telescopic rod 133 and the force transmission rod 12 is less than the distance between the second end of the elastic telescopic rod 133 and the force transmission rod 12. The first end of the elastic telescopic rod 133 faces one end of the first connecting member 131, and the second end of the elastic telescopic rod 133 faces one end of the second connecting member 132, and the first connecting member 131 is located between the second connecting member 132 and the pressure plate 11.

[0061] In the above implementation, the arrangement of the two elastic telescopic rods 133 can further increase the absorption of the pressure received by the first connecting member 131 and the second connecting member 132, thereby increasing the buffering effect of the shock absorption device 13.

[0062] In addition, an angle is formed between the elastic telescopic rod 133 and the force transmission rod 12. In this way, the lateral acting force received by the pressure plate 11 can be offset by the offset between the elastic telescopic rod 133 and the force transmission rod 12 and the hinge method, so as to ensure that the pressure sensor does not shift, and the pressure plate 11 only receives the vertical acting force, ultimately improving the detection accuracy of the pressure sensor.

[0063] Of course, the number of the elastic telescopic rods 133 can also be other numbers, such as four, and the four elastic telescopic rods 133 are symmetrically located on both sides of the axis of the force transmission rod 12 in pairs. In fact, as long as the arrangement of the elastic telescopic rods 133 can slow down the pressure received by the force transmission rod 12 and ensure that the force transmission rod 12 can maintain balance when receiving pressure, the number of the elastic telescopic rods 133 can be freely selected.

[0064] Optionally, the elastic telescopic rod 133 includes a telescopic cylinder 1331, an elastic telescopic member 1332, and a connecting rod 1333. The elastic telescopic member 1332 is movably located within the telescopic cylinder 1331 along the axis of the telescopic cylinder 1331. The first end of the elastic telescopic member 1332 is connected to the inner wall of the telescopic cylinder 1331, and the second end of the elastic telescopic member 1332 is connected to the first end of the connecting rod 1333.

[0065] The telescopic cylinder 1331 is hinged to the second connecting member 132, and the second end of the connecting rod 1333 is connected to the first connecting member 131.

[0066] In the above implementation, the elastic telescopic rod 133 is provided as the telescopic cylinder 1331, the elastic telescopic member 1332, and the connecting rod 1333. In this way, the connecting rod 1333 can be connected to the first connecting member 131, the telescopic cylinder 1331 can be connected to the second connecting member 132, and the telescopic cylinder 1331 and the connecting rod 1333 can be connected by the elastic telescopic member 1332. Furthermore, the connecting rod 1333 can move relative to the telescopic cylinder 1331, and at the same time, energy absorption is performed through the elastic telescopic member 1332, effectively buffering the pressure between the first connecting member 131 and the second connecting member 132.

[0067] Exemplarily, the elastic telescopic member 1332 is a telescopic spring. This can conveniently meet the above usage requirements.

[0068] In addition, the first connecting member 131 is a rod-shaped structural member, and the second connecting member 132 is a plate-shaped structural member. The planes where the first connecting member 131 and the second connecting member 132 are located are arranged in parallel. This can facilitate the connection of the first connecting member 131 and the second connecting member 132 to the force transmission rod 12 respectively.

[0069] The first connecting member 131 and the force transmission rod 12 can be an integral structural member, or they can of course be directly welded together. This can improve the connection strength and manufacturing efficiency between the first connecting member 131 and the force transmission rod 12.

[0070] Exemplarily, the housing 3 is an aluminum structural member. This can not only reduce the cost of the housing 3 but also facilitate purchase.

[0071] The embodiment of the present disclosure further provides a detection system for a pressure sensor. The detection system includes a pressure sensor and at least one demodulator. The pressure sensor is the pressure sensor described above. At least one demodulator is located outside the housing 3, and at least one demodulator is respectively connected to both ends of the first optical fiber 23.

[0072] The above detection system has the same beneficial effects as the pressure sensor and will not be elaborated here.

[0073] In addition, when the pressure sensor includes the first fiber Bragg grating 21 and the second fiber Bragg grating 24, and when the first optical fiber 23 and the second optical fiber 25 are connected in series with a demodulator. In this way, during detection, when the demodulator emits a broadband light passing through the first fiber Bragg grating 21 and the second fiber Bragg grating 24, the first fiber Bragg grating 21 will reflect a narrowband light of a certain central wavelength. At the same time, the second fiber Bragg grating 24 will also reflect a narrowband light of another central wavelength. The demodulator obtains different reflected central wavelengths according to the different deformations of the first fiber Bragg grating 21 and the second fiber Bragg grating 24, so that the measured strain value can be obtained according to the reflected central wavelengths of the first fiber Bragg grating 21 and the second fiber Bragg grating 24.

[0074] When the first fiber Bragg grating 21 and the second fiber Bragg grating 24 in the pressure sensor are not connected in series with a single demodulator, that is, the first optical fiber 23 and the second optical fiber 25 are not connected in series with each other. At this time, there are two demodulators. One demodulator is connected to the first optical fiber 23, and the other demodulator is connected to the second optical fiber 25. In this way, the two demodulators obtain the measured strain value according to the information of the reflected central wavelengths of the fiber Bragg gratings corresponding to them respectively. In this case, the reflected central wavelength of the first fiber Bragg grating 21 and the reflected central wavelength of the second fiber Bragg grating 24 can be the same or different.

[0075] The following briefly introduces the detection process of the pressure sensor provided by the present disclosure:

[0076] First, connect the pressure plate of the pressure sensor to the object to be measured.

[0077] During detection, the pressure sensor can be placed in the detection environment according to the actual situation. For example, for the pressure on the bridge pier, the chassis of the pressure sensor can be placed under the bridge pier at this time.

[0078] Next, obtain the wavelength drift amount of the fiber Bragg grating in the pressure sensor.

[0079] In this embodiment, when there is only the first fiber Bragg grating, the wavelength drift amount of the fiber Bragg grating refers to the wavelength drift amount of the corresponding fiber Bragg grating.

[0080] When the first fiber Bragg grating and the second fiber Bragg grating are included, the wavelength drift amount of the fiber Bragg grating refers to the difference between the wavelength drift amounts of the first fiber Bragg grating and the second fiber Bragg grating.

[0081] Of course, when the first fiber Bragg grating and the second fiber Bragg grating are included, for the convenience of connecting the pressure sensor to the demodulator, the first fiber Bragg grating and the second fiber Bragg grating of the pressure sensor are connected to the same demodulator.

[0082] During detection, both the first fiber Bragg grating and the second fiber Bragg grating are connected to the demodulator through the same optical fiber. The reflection center wavelengths of the first fiber Bragg grating and the second fiber Bragg grating are different. The initial center wavelengths of the first fiber Bragg grating and the second fiber Bragg grating are the same. The broadband light emitted by the demodulator passes through the first fiber Bragg grating and the second fiber Bragg grating in sequence. When the broadband light passes through the first fiber Bragg grating, the first fiber Bragg grating will reflect a part of the broadband light to obtain narrowband light with a certain center wavelength, and this narrowband light is transmitted back to the demodulator for recording. Another part of the broadband light emitted from the demodulator continues to propagate forward to the second fiber Bragg grating, and the second fiber Bragg grating will reflect this part of the broadband light to obtain narrowband light with another center wavelength, and this narrowband light is also transmitted back to the demodulator for recording.

[0083] Because the reflection center wavelengths of the first fiber Bragg grating and the second fiber Bragg grating are different. In this way, a demodulator can automatically identify the detection signals of different fiber Bragg gratings.

[0084] Then, according to the wavelength drift amount, the magnitude of the detected pressure is determined.

[0085] Since the relationship between the wavelength drift amount Δλ of the fiber Bragg grating and the axial strain Δε it undergoes and the environmental temperature change ΔT is:

[0086]

[0087] where α f is the thermal expansion coefficient of the first optical fiber and the second optical fiber; ξ is the thermo-optic coefficient of the first optical fiber and the second fiber Bragg grating; P e is the effective elasto-optic coefficient of the first optical fiber and the second optical fiber (at room temperature, P e is approximately equal to 0.22).

[0088] Therefore, when the sensing sphere moves downward under pressure, it will cause the wavelength of the fiber Bragg grating to change, and finally the detected pressure can be obtained by measuring the wavelength drift amount of the fiber Bragg grating.

[0089] The above are only optional embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

1. A pressure sensor, characterized in that, The pressure sensor includes a pressure-receiving component (1), a fiber Bragg grating component (2), and a housing (3). The pressure-receiving component (1) includes a pressure plate (11), a force-transmitting rod (12), and a shock-absorbing device (13). The first end of the force-transmitting rod (12) is connected to one side of the pressure plate (11), and the shock-absorbing device (13) is connected to the middle of the force-transmitting rod (12). The fiber Bragg grating component (2) includes a first fiber Bragg grating (21), a sensing sphere (22), and a first optical fiber (23). The first fiber Bragg grating (21) is connected in series with the first optical fiber (23). The first optical fiber (23) is in contact with the outer wall of the sensing sphere (22). The length direction of the first optical fiber (23) is perpendicular to the axis direction of the force-transmitting rod (12). The first side of the sensing sphere (22) is connected to the second end of the force-transmitting rod (12). Along the axis direction of the force-transmitting rod (12), the second side of the sensing sphere (22) and the first side of the sensing sphere (22) are respectively located on both sides of the center point of the sensing sphere (22). The sensing sphere (22) is an ellipsoid, and the major axis direction of the sensing sphere (22) is the same as the axis direction of the force-transmitting rod (12). The first optical fiber (23) is located between the center point and the second side of the sensing sphere (22). The pressure plate (11) is located outside the housing (3), and the force-transmitting rod (12) and the shock-absorbing device (13) are both located inside the housing (3). The fiber Bragg grating component (2) is located inside the housing (3).

2. The pressure sensor according to claim 1, characterized in that, The fiber Bragg grating component (2) further includes a second fiber Bragg grating (24) and a second optical fiber (25). The second fiber Bragg grating (24) is connected in series with the second optical fiber (25). The second optical fiber (25) is in contact with the outer wall of the sensing sphere (22). The first optical fiber (23) and the second optical fiber (25) are parallel to each other. Along the axis direction of the force-transmitting rod (12), the first optical fiber (23) and the second optical fiber (25) are respectively located on both sides of the center point of the sensing sphere (22).

3. The pressure sensor according to claim 1, wherein, The shock-absorbing device (13) includes a first connecting member (131), a second connecting member (132), and an elastic telescopic rod (133). The first connecting member (131) is connected to the middle of the force-transmitting rod (12). The second connecting member (132) is slidably connected to the middle of the force-transmitting rod (12), and the second connecting member (132) is connected to the inner wall of the housing (3). The first connecting member (131) and the second connecting member (132) are arranged at intervals. The elastic telescopic rod (133) is located between the first connecting member (131) and the second connecting member (132). The two ends of the elastic telescopic rod (133) are respectively hinged to the first connecting member (131) and the second connecting member (132).

4. The pressure sensor according to claim 3, characterized in that, The elastic telescopic rods (133) are two, and the two elastic telescopic rods (133) are symmetrically arranged with the axis of the force transmission rod (12) as the axis of symmetry. An included angle is formed between the elastic telescopic rod (133) and the force transmission rod (12), and the distance between the first end of the elastic telescopic rod (133) and the force transmission rod (12) is less than the distance between the second end of the elastic telescopic rod (133) and the force transmission rod (12). The first end of the elastic telescopic rod (133) faces one end of the first connector (131), the second end of the elastic telescopic rod (133) faces one end of the second connector (132), and the first connector (131) is located between the second connector (132) and the pressure plate (11).

5. The pressure sensor according to claim 3, wherein The elastic telescopic rod (133) includes a telescopic cylinder (1331), an elastic telescopic member (1332), and a connecting rod (1333). The elastic telescopic member (1332) is movably located in the telescopic cylinder (1331) along the axis of the telescopic cylinder (1331), and the first end of the elastic telescopic member (1332) is connected to the inner wall of the telescopic cylinder (1331), and the second end of the elastic telescopic member (1332) is connected to the first end of the connecting rod (1333). The telescopic cylinder (1331) is hinged to the second connector (132), and the second end of the connecting rod (1333) is connected to the first connector (131).

6. The pressure sensor according to any one of claims 1 to 5, characterized in that, The fiber grating assembly (2) further includes at least a pair of fixed supports (26). Along the direction perpendicular to the axis of the force transmission rod (12), the at least a pair of fixed supports (26) are respectively located on opposite sides of the sensing ball (22), and the first optical fiber (23) is fixedly connected to the at least a pair of fixed supports (26) respectively.

7. The pressure sensor according to claim 6, characterized in that, The fixed support (26) includes an outer sleeve (261) and a core tube (262). The core tube (262) is located in the outer sleeve (261), and both ends of the core tube (262) are connected to the outer sleeve (261) respectively. The core tube (262) is sleeved outside the first optical fiber (23).

8. The pressure sensor according to any one of claims 1 to 5, characterized in that, The sensing ball (22) is a soft rubber structural member.

9. A detection system for a pressure sensor, characterized in that, The detection system includes a pressure sensor and a demodulator. The pressure sensor is the pressure sensor according to any one of claims 1 to 8, and the demodulator is connected to both ends of the first optical fiber.

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