Fiber bragg grating osmometer

Abstract

The invention relates to the technical field of optical fiber sensing, in particular to an optical fiber grating osmometer which comprises a water permeable module, a sensing module, a packaging module and a signal transmission module. The sensing module comprises a diaphragm close to one end of the water permeable module, a machine core shell connected with the diaphragm, and a machine core frame, a machine core, a pressure sensing fiber bragg grating and a temperature sensing fiber bragg grating which are arranged in the machine core shell; the machine core frame is fixedly connected with the diaphragm; the movement comprises an elastic carrier used for bearing the pressure sensing fiber grating, one end, close to the diaphragm, of the elastic carrier is connected with a first connecting piece, the first connecting piece is fixedly connected with the movement frame, one end, away from the diaphragm, of the elastic carrier is connected with a second connecting piece, and one end, close to the diaphragm, of the second connecting piece is fixedly connected with the diaphragm; the pressure sensing fiber bragg grating is located on a center shaft of the movement, and when the diaphragm is pressed, the elastic carrier drives the pressure sensing fiber bragg grating to generate stretching deformation in the axial direction of the movement. The fiber bragg grating osmometer solves the problem that the traditional fiber bragg grating osmometer is easy to generate null drift, and improves the precision and reliability of the product.

Description

Technical Field

[0001] The present application relates to the technical field of optical fiber sensing, and in particular to a fiber Bragg grating osmometer. Background Art

[0002] Fiber Bragg grating (FBG) sensor technology, developed in the 1980s, offers advantages such as real-time monitoring, immunity to electromagnetic interference, and lightning strike resistance. With technological advancements, its measurement accuracy and reliability have continued to improve, and its application areas have continued to expand. Fiber Bragg grating (FBG) piezometers, a derivative of this technology, have found widespread application in water conservancy projects, geotechnical engineering, and other fields.

[0003] Currently, traditional fiber Bragg grating piezometers have certain operational issues. For example, a Chinese patent (patent number: ZL201020655834.3) discloses a grating water pressure sensor, comprising a sleeved grating protection tube and an outer tube, a permeable seat embedded in the front end of the outer tube, a permeable stone embedded in the permeable seat, a movement seat connected to the front end of the grating protection tube and the inner wall of the outer tube, a diaphragm located at the front end of the movement seat, a rear plug inserted into the grating protection tube and the rear end of the outer tube, an armored connector inserted into the rear plug, and an armored optical cable inserted into the armored connector. A strain frame is connected between the diaphragm and the movement seat, a grating is attached to the strain frame, and the grating is connected to the armored optical cable via optical fiber.

[0004] The working principle of this grating water pressure sensor is as follows: water penetrates through the permeable stone into the cavity formed by the permeable seat, the outer cylinder and the sensor movement. The water pressure outside the permeable stone gradually increases, causing the water pressure inside the cavity to increase. In this way, the water pressure will squeeze the diaphragm, causing the deflection of the diaphragm concave to change, driving the moving end of the strain frame connected to the diaphragm end to change, thereby causing the strain frame to compress and deform, causing the wavelength of the grating bonded to the strain frame to change, and then the optical signal is transmitted through the optical fiber. The signal is demodulated by the demodulator to obtain the pressure change value.

[0005] However, when the grating water pressure sensor is placed for a long time, the fiber Bragg grating is prone to zero drift, and the fiber Bragg grating is easily broken during transportation vibration, making the fiber Bragg grating osmometer ineffective.

[0006] Therefore, developing a fiber Bragg grating piezometer that is not prone to zero drift and is not easily damaged has become an important issue that needs to be solved urgently. Summary of the Invention

[0007] In order to solve the technical problem that the internal grating of the existing fiber Bragg grating osmometer is prone to zero drift, the present application provides a fiber Bragg grating osmometer.

[0008] A fiber Bragg grating osmometer includes a water permeability module, a sensing module, a packaging module, and a signal transmission module. The water permeability module transmits the water pressure of the external environment to the sensing module. The sensing module is arranged in the packaging module and is used to sense the water pressure and convert it into an optical signal. The signal transmission module is connected to the sensing module and is used to transmit the optical signal to an external regulating device. The sensing module includes a diaphragm near one end of the water permeable module, a core housing fixedly connected to the diaphragm, and a core frame, a core, a pressure-sensitive fiber Bragg grating, and a temperature-sensitive fiber Bragg grating arranged in the core housing; The core frame is located on the side of the membrane away from the water permeable module, and the membrane is fixedly connected to the core frame; The movement includes an elastic carrier for carrying the pressure-sensitive fiber Bragg grating, the elastic carrier having an end close to the diaphragm connected to a first connecting member, the first connecting member being fixedly connected to the movement frame, the elastic carrier having an end away from the diaphragm connected to a second connecting member, the end of the second connecting member close to the diaphragm being fixedly connected to the diaphragm; The pressure-sensitive fiber Bragg grating is located on the central axis of the core, and when the diaphragm is under pressure, the elastic carrier drives the pressure-sensitive fiber Bragg grating to generate tensile deformation along the axial direction of the core; The core also includes a bearing seat for bearing a temperature-sensitive fiber Bragg grating. The temperature-sensitive fiber Bragg grating is located on the central axis of the core and is connected to the pressure-sensitive fiber Bragg grating.

[0009] According to the inventor's analysis, the reason why the grating water pressure sensor disclosed in the above-mentioned patent 201020655834.3 is prone to zero drift problems is that the fiber Bragg grating converts the compressive deformation of the fiber Bragg grating into an optical signal by measuring the compressive deformation of the fiber Bragg grating. In order to adapt to the compressive deformation of the fiber Bragg grating, the fiber Bragg grating is in a state of extremely high pre-tension in the initial state. However, as time goes by, due to problems such as stress relaxation or creep of the core material, the pre-tension acting on the fiber Bragg grating decreases, and the fiber Bragg grating exhibits compressive strain in a pressure-free state, thereby causing a zero drift problem.

[0010] In the fiber optic Bragg grating osmometer of the present application, the first connecting part of the movement is fixed to the movement frame. When the diaphragm is subjected to the water pressure of the permeable module, the diaphragm is compressed and the deformation is transmitted to the far end of the movement through the second connecting part. The pressure exerted on the movement is converted into tensile stress on the movement. As the pressure increases, the elongation of the pressure-sensitive fiber optic Bragg grating increases. Therefore, the present invention enables the pressure-sensitive fiber optic Bragg grating to be in an extremely low tensile stress state in the initial state, and the elongation of the pressure-sensitive fiber optic Bragg grating gradually increases after loading, effectively solving the technical problem that the existing fiber optic Bragg grating osmometer is prone to zero drift. It not only improves the reliability of the fiber optic Bragg grating, but also reduces the risk of damage to the internal structure of the osmometer, and further improves the measurement accuracy of the pressure-sensitive fiber optic Bragg grating osmometer.

[0011] In addition, the movement includes an elastic carrier for carrying a pressure-sensitive fiber grating and a supporting seat for carrying a temperature-sensitive fiber grating. On the one hand, the movement protects the pressure-sensitive fiber grating and the temperature-sensitive fiber grating, thereby improving the reliability of the pressure-sensitive fiber grating and the temperature-sensitive fiber grating in the osmometer; on the other hand, the elastic carrier drives the pressure-sensitive fiber grating to produce tensile deformation along the axial direction of the movement, and the temperature-sensitive fiber grating is connected to the pressure-sensitive fiber grating. The temperature-sensitive fiber grating can further reduce the influence of temperature on pressure measurement and improve the measurement accuracy of the fiber grating osmometer.

[0012] Furthermore, the pressure-sensitive fiber Bragg grating and the temperature-sensitive fiber Bragg grating are fixed on the central axis of the movement by welding.

[0013] Through the above technical solution, the fiber Bragg grating is fixed by high-temperature welding instead of traditional adhesive fixation, which further reduces the risk of creep or falling off of the fiber Bragg grating during long-term use, effectively improves the reliability of the fiber Bragg grating, solves the problem of poor consistency of mass-produced products, and further improves the measurement accuracy of the fiber Bragg grating piezometer.

[0014] Furthermore, the elastic carrier includes a deformation component, and the deformation component includes two deformation members symmetrically arranged along the axis of the pressure-sensitive fiber Bragg grating.

[0015] Through the above technical solution, since the deformable parts are symmetrically distributed along the axis of the pressure-sensitive fiber Bragg grating, after the deformable parts are subjected to a tensile force, their deformation acts on both sides of the pressure-sensitive fiber Bragg grating, realizing the axial strain of the pressure-sensitive fiber Bragg grating, and ensuring that the force acting on the pressure-sensitive fiber Bragg grating is evenly distributed. Furthermore, the symmetrical deformation of the deformable parts can avoid local distortion of the pressure-sensitive fiber Bragg grating, ensuring that the pressure-sensitive fiber Bragg grating can be deformed along the axial direction, so that the pressure-sensitive fiber Bragg grating can be subjected to uniform force, making it easier for the pressure-sensitive fiber Bragg grating to return to its initial state after the pressure is removed, further preventing the zero drift problem of the fiber Bragg grating, and being beneficial to improving the measurement accuracy of the fiber Bragg grating osmometer.

[0016] Furthermore, the deformable member includes a connecting portion and movable portions provided at both ends of the connecting portion, and the movable portions at both ends are deformed and extended along the axial direction of the pressure-sensitive fiber Bragg grating.

[0017] Through the above technical solution, the free telescopic design of the movable part can further amplify small deformations and further improve the response ability of the fiber Bragg grating to small pressure changes, thereby improving the sensitivity and measurement accuracy of the fiber Bragg grating piezometer.

[0018] Furthermore, the deformable components are provided in at least two groups, a plurality of the deformable members are distributed in sequence along the axial direction of the pressure-sensitive fiber Bragg grating, and two adjacent deformable members are connected in sequence.

[0019] Through the above technical solution, multiple groups of deformation components are provided, which are suitable for large-scale pressure monitoring, and the sequential distribution of multiple adjacent deformation components will make the tensile deformation of the elastic carrier more uniform, thereby making the strain evenly transmitted along the axial direction of the pressure-sensitive fiber Bragg grating. On the other hand, the movable parts at both ends of a single deformation component have smaller telescopic deformation and can return to their original state more freely. Therefore, the pressure-sensitive fiber Bragg grating can also return freely and will not be in a stretched state for a long time, further reducing the zero drift of the pressure-sensitive fiber Bragg grating, which is beneficial to improving the measurement accuracy of the fiber Bragg grating.

[0020] Furthermore, the movement frame includes a first mounting seat and a second mounting seat, the first mounting seat is fixedly connected to the movement through the first connecting member, and the first mounting seat is tightly combined with the inner side of the movement housing, and the second mounting seat is fixedly connected to the diaphragm.

[0021] Through the above technical solution, the movement frame improves the installation stability of the movement frame through the arrangement of the first mounting seat and the second mounting seat, prevents the movement on the movement frame from shaking and affecting the measurement accuracy of the optical efficiency grating, and improves the reliability of the fiber grating. Moreover, since the pressure-sensitive fiber grating is arranged on the central axis of the movement, the stability of the movement frame can further stabilize the pressure-sensitive fiber grating on the movement, and can further reduce the zero drift of the pressure-sensitive fiber grating.

[0022] Furthermore, the permeable module includes a permeable seat and a permeable stone, and the permeable stone is installed on the permeable seat.

[0023] Through the above technical solution, the permeable stone can intercept sediment particles, guide water flow to penetrate quickly and maintain pressure transmission efficiency, is suitable for underwater environment, and the permeable stone can be independently disassembled, cleaned or replaced, thereby increasing the life of the permeable module.

[0024] Furthermore, the packaging module includes an osmometer outer cylinder and an osmometer rear plug, and the sensor modules are all arranged in the osmometer outer cylinder. One end of the osmometer outer cylinder is fixedly connected to the permeable module, and the other end is fixedly connected to the osmometer rear plug.

[0025] Through the above technical solution, the outer side of the movement shell of the sensor module is tightly connected to the inner side of the outer tube of the piezometer. The water-permeable module is arranged at one end of the piezometer to transmit the water pressure of the external environment to the sensor module, and the other end is sealed by the back plug of the piezometer to prevent liquid intrusion from affecting the measurement accuracy of the fiber Bragg grating, thereby improving the sealing of the fiber Bragg grating piezometer.

[0026] Furthermore, the signal transmission module includes an armored joint, an armored optical cable and a stainless steel casing. The armored joint is arranged on the rear plug of the piezometer, and the armored optical cable is connected to the armored joint through the stainless steel casing.

[0027] Through the above technical solution, the armored optical cable is connected to the armored joint through the stainless steel sleeve, which can further enhance the stability of the connection between the armored joint and the armored optical cable and reduce the damage to the signal transmission module caused by external force.

[0028] Furthermore, a thick tail casing is also provided outside the stainless steel casing.

[0029] Through the above technical solution, the setting of the thick tail sleeve provides additional mechanical protection for the armored optical cable, and the external setting of the thick tail sleeve can reduce the entry of external moisture into the interior of the fiber Bragg grating piezometer and improve the sealing of the product.

[0030] In summary, this application has at least the following beneficial effects: 1. The fiber Bragg grating osmometer of the present application enables the fiber Bragg grating to be in an extremely low tensile stress state in its initial state. The elongation of the fiber Bragg grating increases gradually after loading. This effectively solves the technical problem of existing fiber Bragg grating osmometers being prone to zero drift due to being in a high tension state for a long time. This not only improves the reliability of the fiber Bragg grating and reduces the risk of damage to the internal structure of the osmometer, but also further improves the measurement accuracy of the fiber Bragg grating osmometer. 2. The fiber Bragg grating (FBG) osmometer of this application uses high-temperature welding to fix the fiber Bragg grating (FBG) instead of traditional adhesive fixation, further reducing the risk of FBG creep or fall-off during long-term use. This effectively improves the reliability of the FBG, solves the problem of poor consistency in mass-produced products, and further improves the measurement accuracy of the FBG osmometer. 3. The elastic carrier of the fiber Bragg grating osmometer of the present application is provided with a deformable part, which is symmetrically distributed along the axis of the pressure-sensitive fiber Bragg grating. When the deformable part is subjected to a tensile force, its deformation acts on both sides of the pressure-sensitive fiber Bragg grating, realizing the axial strain of the pressure-sensitive fiber Bragg grating, and can ensure that the force acting on the pressure-sensitive fiber Bragg grating is evenly distributed. Furthermore, the symmetrical deformation of the deformable part can avoid local distortion of the pressure-sensitive fiber Bragg grating, and effectively improve the measurement accuracy of the fiber Bragg grating osmometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 1 is a schematic diagram of the AA section line of the right side view of a fiber Bragg grating piezometer provided by an embodiment of the present invention; Figure 2 1 is an AA cross-sectional view of a fiber Bragg grating piezometer provided by an embodiment of the present invention; Figure 3 BB section diagram of a right view of a fiber Bragg grating piezometer provided by an embodiment of the present invention; Figure 4 is a cross-sectional view of a fiber Bragg grating osmometer provided by an embodiment of the present invention; Figure 5This is a partial structural diagram of a fiber Bragg grating piezometer provided by an embodiment of the present invention; Figure 6 It is an enlarged view of a portion of the structure of a fiber Bragg grating piezometer provided by an embodiment of the present invention.

[0032] Description of reference numerals: 1. Permeable module; 11. Permeable seat; 12. Permeable stone; 2. Sensing module; 21. Diaphragm; 22. Movement housing; 23. Movement frame; 24. Movement; 25. Fiber Bragg grating (FBG); 221. Movement outer tube; 222. Movement back plug; 231. First mounting seat; 232. Second mounting seat; 241. Elastic carrier; 242. Bearing seat; 243. First connecting member; 244. Second connecting member; 245. First welding port; 246. Second welding port; 247. Third welding port; 251. Pressure-sensitive fiber Bragg grating (FBG); 252. Temperature-sensitive fiber Bragg grating (FBG); 2411. Deformation member; 2431. First screw; 2441. Second screw; 24111. Connecting part; 24112. First movable part; 24113. Second movable part.

[0033] 3. Encapsulation module; 31. Osmometer outer cylinder; 32. Osmometer rear plug; 4. Signal transmission module; 41. Armored connector; 42. Armored optical cable; 43. Stainless steel casing; 44. Thick tail casing. DETAILED DESCRIPTION

[0034] The following is combined with Figure 1-6 Further explanation of this application.

[0035] See Figure 1-2 The present invention provides a fiber Bragg grating piezometer, including a water permeability module 1, a sensing module 2, a packaging module 3 and a signal transmission module 4. The water permeability module 1 transmits the water pressure of the external environment to the sensing module 2. The sensing module 2 is arranged in the packaging module 3 and is used to sense the water pressure and convert it into an optical signal; the signal transmission module 4 is connected to the sensing module 2 and is used to transmit the optical signal to an external device.

[0036] Among them, the permeable module 1 includes a permeable seat 11 and a permeable stone 12, and the permeable stone 12 is embedded in the front end of the permeable seat 11; the sensor module 2 includes a diaphragm 21 close to one end of the permeable seat 11, a movement shell 22 fixedly connected to the diaphragm 21, and a movement frame 23, a movement 24, and a fiber optic Bragg grating 25 arranged in the movement shell 22. The movement frame 23 is located on the side of the diaphragm 21 away from the permeable seat 11 and is fixedly connected to the diaphragm 21. The movement 24 is fixed on the movement frame 23, and the end of the movement 24 close to the diaphragm 21 is fixed to the diaphragm 21. The fiber optic Bragg grating 25 is fixed on the movement 24. The movement shell 22 includes a movement outer tube 221 and a movement back plug 222. One end of the movement outer tube 221 is connected to the diaphragm 21, and the end away from the diaphragm 21 is connected to the movement back plug 222.

[0037] Specifically, in this embodiment, the diaphragm 21 is a cover-shaped structure, the movement frame 23 and the diaphragm 21 are fixed by threaded connection, and the diaphragm 21 and the movement back plug 222 are fixed to the movement outer cylinder 221 by welding.

[0038] See Figure 3-5 The fiber Bragg grating 25 includes a pressure-sensitive fiber Bragg grating 251 and a temperature-sensitive fiber Bragg grating 252, which are connected to each other. The pressure-sensitive fiber Bragg grating 251 and the temperature-sensitive fiber Bragg grating 252 are located on the central axis of the movement 24; wherein, the movement 24 includes an elastic carrier 241 for carrying the pressure-sensitive fiber Bragg grating 251 and a supporting seat 242 for carrying the temperature-sensitive fiber Bragg grating 252, and the end of the elastic carrier 241 close to the diaphragm 21 is connected to a first connecting member 243, and the first connecting member 243 is fixedly connected to the first mounting seat 231 of the movement frame 23 through a first screw 2431, and a second connecting member 244 is provided at the end of the elastic carrier 241 away from the diaphragm 21, and the end of the second connecting member 244 close to the diaphragm 21 is fixedly connected to the diaphragm 21 through the second mounting seat 232 of the movement frame 23 through a second screw 2441. When the diaphragm 21 is compressed, the core 24 is subjected to the pressure of the diaphragm 21 , forming a tensile force at the distal end of the core 24 , and the elastic carrier 241 drives the pressure-sensitive fiber Bragg grating 251 to generate tensile deformation along the axial direction of the core 24 .

[0039] Specifically, in this embodiment, the first mounting seat 231 of the movement frame 23 is tightly connected to the inner side of the movement housing 22, further improving the installation stability of the movement frame.

[0040] See Figure 6The elastic carrier 241 includes a deformation component, which includes two deformable parts 2411 symmetrically arranged along the axis of the pressure-sensitive fiber Bragg grating 251. The deformable part includes a connecting portion 24111 and a first movable portion 24112 and a second movable portion 24113 arranged on both sides of the connecting portion. The first movable portion 24112 and the second movable portion 24113 are deformed and extended along the axial direction of the pressure-sensitive fiber Bragg grating, and the distance between the first movable portion 24112 and the second movable portion 24113 increases as the pressure-sensitive fiber Bragg grating 251 is stretched, and the initial distance is restored as the pressure-sensitive fiber Bragg grating is reset.

[0041] In this embodiment, two groups of deformation components are provided, and two adjacent deformation components 2411 are connected in sequence and distributed in sequence along the axial direction of the pressure-sensitive fiber Bragg grating 251 .

[0042] Specifically, the elastic carrier adopts titanium alloy as the main material, which further improves the rigidity of the fiber Bragg grating piezometer and also improves the corrosion resistance of the internal accessories of the piezometer.

[0043] Continue reading Figure 5 The pressure-sensitive fiber Bragg grating 251 and the temperature-sensitive fiber Bragg grating 252 are fixed on the central axis of the movement 24 by welding. The movement 24 is provided with a first welding port 245, a second welding port 246 and a third welding port 247. The pressure-sensitive fiber Bragg grating 251 is arranged between the first welding port 245 and the second welding port 246, and the temperature-sensitive fiber Bragg grating 252 is arranged between the second welding port 246 and the third welding port 247.

[0044] See Figure 2 The packaging module 3 includes an osmometer outer cylinder 31, one end of which is fixedly connected to the permeable seat 11, and the other end is provided with an osmometer back plug 32. The sensor module 2 is arranged in the osmometer outer cylinder 31, and the outer side of its core housing 22 is tightly connected to the inner side of the osmometer outer cylinder 31. The signal transmission module 4 includes an armored connector 41, an armored optical cable 42, a stainless steel sleeve 43 and a thick tail sleeve 44. The armored connector 41 is arranged on the osmometer back plug 32, the armored optical cable 42 is connected to the armored connector 41 through the stainless steel sleeve 43, and the thick tail sleeve 44 is sleeved on the outside of the stainless steel sleeve 43. The optical fiber of the fiber grating 25 inside the sensor module 2 is connected to the armored optical cable 42 through the core back plug 222 and the osmometer back plug 32 in sequence.

[0045] The working principle of the embodiment of the present invention is as follows: Figure 2As shown, water penetrates through the permeable stone 12 into the cavity formed by the permeable seat 11, the outer tube 31 of the piezometer and the sensor module 2. The water pressure outside the permeable stone 12 gradually increases, causing the water pressure in the cavity to increase. The diaphragm 21 is subjected to the water pressure, which drives the far end of the movement 24 connected to the diaphragm 21 to generate a tensile force, thereby causing the elastic carrier 241 in the movement 24 to be stretched and deformed, causing the pressure-sensitive fiber grating 251 welded on the movement 24 to change its wavelength, and then the optical signal is transmitted through the optical fiber, and the signal is demodulated by the demodulator to obtain the pressure change value.

[0046] The above are preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A fiber Bragg grating osmometer, characterized in that: The system comprises a water permeable module, a sensing module, a packaging module and a signal transmission module. The water permeable module transmits the water pressure of the external environment to the sensing module. The sensing module is arranged in the packaging module and is used to sense the water pressure and convert it into an optical signal. The signal transmission module is connected to the sensing module and is used to transmit the optical signal to an external regulating device. The sensing module includes a diaphragm near one end of the water permeable module, a core housing fixedly connected to the diaphragm, and a core frame, a core, a pressure-sensitive fiber Bragg grating, and a temperature-sensitive fiber Bragg grating arranged in the core housing; The core frame is located on the side of the membrane away from the water permeable module, and the membrane is fixedly connected to the core frame; The movement includes an elastic carrier for carrying the pressure-sensitive fiber Bragg grating, the elastic carrier having an end close to the diaphragm connected to a first connecting member, the first connecting member being fixedly connected to the movement frame, the elastic carrier having an end away from the diaphragm connected to a second connecting member, the end of the second connecting member close to the diaphragm being fixedly connected to the diaphragm; The pressure-sensitive fiber Bragg grating is located on the central axis of the core, and when the diaphragm is under pressure, the elastic carrier drives the pressure-sensitive fiber Bragg grating to generate tensile deformation along the axial direction of the core; The core also includes a bearing seat for bearing a temperature-sensitive fiber Bragg grating. The temperature-sensitive fiber Bragg grating is located on the central axis of the core and is connected to the pressure-sensitive fiber Bragg grating.

2. The fiber Bragg grating osmometer according to claim 1, characterized in that: The pressure-sensitive fiber grating and the temperature-sensitive fiber grating are fixed on the central axis of the core by welding.

3. The fiber Bragg grating osmometer according to claim 1, characterized in that: The elastic carrier includes a deformation component, and the deformation component includes two deformation pieces symmetrically arranged along the axis of the pressure-sensitive fiber Bragg grating.

4. The fiber Bragg grating osmometer according to claim 3, characterized in that: The deformable member includes a connecting portion and movable portions arranged at both ends of the connecting portion, and the movable portions at both ends are deformed and extended along the axial direction of the pressure-sensitive fiber Bragg grating.

5. The fiber Bragg grating osmometer according to claim 4, characterized in that: At least two groups of the deformable components are provided, and a plurality of the deformable components are distributed in sequence along the axial direction of the pressure-sensitive fiber grating, and two adjacent deformable components are connected in sequence.

6. The fiber Bragg grating osmometer according to claim 1, characterized in that: The movement frame includes a first mounting seat and a second mounting seat. The first mounting seat is fixedly connected to the movement through the first connecting member, and the first mounting seat is tightly combined with the inner side of the movement housing. The second mounting seat is fixedly connected to the diaphragm.

7. The fiber Bragg grating osmometer according to claim 1, characterized in that: The permeable module includes a permeable seat and a permeable stone, and the permeable stone is installed on the permeable seat.

8. The fiber Bragg grating osmometer according to claim 1, characterized in that: The packaging module includes an osmometer outer cylinder and an osmometer rear plug. The sensor modules are all arranged in the osmometer outer cylinder. One end of the osmometer outer cylinder is fixedly connected to the water permeability module, and the other end is fixedly connected to the osmometer rear plug.

9. The fiber Bragg grating osmometer according to claim 8, characterized in that: The signal transmission module includes an armored joint, an armored optical cable and a stainless steel casing. The armored joint is arranged on the rear plug of the piezometer, and the armored optical cable is connected to the armored joint through the stainless steel casing.

10. The fiber Bragg grating osmometer according to claim 9, characterized in that: A thick tail casing is also sleeved on the outside of the stainless steel casing.

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