1. A manufacturing and packaging method of a fish-shaped fiber grating pressure and temperature sensor is characterized by comprising the following steps:

s1: preparing fish-shaped metal sheets: punching the metal sheet into a fishbone shape, arranging connecting holes at two ends of the metal sheet, and punching the metal sheet into a streamline with a convex middle part; one metal sheet is symmetrically provided with longitudinal grooves along two sides of a longitudinal central axis of the metal sheet, and the longitudinal grooves are set as female metal sheets; taking another metal sheet, symmetrically forming rib grooves protruding outwards in the longitudinal direction along two sides of a longitudinal central axis, and setting the rib grooves as male surface metal sheets; the female metal sheet and the male metal sheet have the same quantity of bone spurs and are symmetrically arranged;

s2: manufacturing a temperature measuring unit:

manufacturing a temperature measuring metal sheet: punching a strip-shaped metal sheet into an arc shape along the longitudinal axis of the metal sheet, performing turned-up flanging shearing treatment, inserting a flanged edge obtained after shearing the metal sheet into the inner side position of a rib groove of the male metal sheet, ensuring that the longitudinal axis of the strip-shaped metal sheet is straight, forming a closed sealing cavity by the strip-shaped metal sheet and the rib groove of the male metal sheet, and setting the strip-shaped metal sheet as a temperature measuring metal sheet;

manufacturing a partition plate: taking at least two metal sheets, shearing the metal sheets into at least two partition plates according to the shapes of different cross sections of the central axis of the sealed cavity, shearing flow through holes at the edges of the partition plates, punching mounting holes in the middle of the partition plates, and arranging the partition plates at corresponding cross sections in the sealed cavity;

manufacturing a temperature measurement grating sensitization piece: punching another strip-shaped metal sheet into an arc shape along the longitudinal axis according to the size of the mounting hole in the middle of the partition plate, and performing turned-up edge shearing treatment on the metal sheet to enable the metal sheet to penetrate into the mounting hole in the middle of the partition plate and set the metal sheet as a temperature-measuring grating sensitizing piece; placing a temperature-measuring grating sensitizing piece in the mounting hole of the partition plate, wherein one end of the temperature-measuring grating sensitizing piece is fixedly connected with one of the partition plates, and the positions of the mounting holes of the other partition plates are abutted with the temperature-measuring grating sensitizing piece, so that the other end of the temperature-measuring grating sensitizing piece is arranged in a suspension manner;

manufacturing a temperature measuring metal wire: welding at least one temperature measuring metal wire on the outer surface of the temperature measuring metal sheet;

s3: manufacturing the fiber grating: selecting four same optical fibers, symmetrically pasting the optical fibers on the central axes of the inner side and the outer side of the female metal sheet respectively, engraving gratings with the same characteristic value on the surface of each optical fiber, ensuring that the gratings on the inner side and the outer side of the middle part of the female metal sheet are in the same characteristic grid period, numbering the optical fiber pasted on the outer side wall of the female metal sheet as a first optical fiber, and numbering the optical fiber pasted on the inner side wall of the female metal sheet as a second optical fiber;

taking one of the remaining two optical fibers as a third optical fiber, enabling the third optical fiber to penetrate through the temperature measurement grating sensitization part along the longitudinal axis direction of the sealed cavity and be adhered to the longitudinal axis position of the concave surface of the temperature measurement grating sensitization part, engraving a grating at the position where the third optical fiber is adhered to the temperature measurement grating sensitization part, wherein the grating characteristic value on the third optical fiber is the same as the grating characteristic value on the first or second optical fiber, and the two ends of the third optical fiber and the temperature measurement metal sheet are adhered to ensure that the third optical fiber in the sealed cavity is in a loose state, wherein the loose state comprises a loose ring arranged on the optical fiber; the slack loop comprises at least one circle of optical fiber winding;

manufacturing a temperature measurement sealing cavity: then sticking or welding the raised end of the temperature measurement metal sheet and the rib groove of the male surface metal sheet together, and sealing after filling a heat-conducting medium of fluid in the sealing cavity to completely seal the sealing cavity; adhering a fourth optical fiber to the central axis of the outer side of the male surface metal sheet, and engraving a grating on the surface of the fourth optical fiber at the middle position of the male surface metal sheet, wherein the grating characteristic values on the fourth optical fiber are the same as those on the third optical fiber;

s4: manufacturing an air bag: filling inert gas into the air bags by using a method of blowing the balloons, wherein the size of each batch of air bags is the same, and ensuring that the two metal sheets are not cracked when being compressed to a plane;

s5: assembling a sensor main body: placing the air bag at the concave position of the female metal sheet stuck with the fiber bragg grating, respectively placing two metal rods with limiting rings in the middle into connecting holes at two ends of the female metal sheet, penetrating corresponding holes of the male metal sheet into the other ends of the two metal rods, and correspondingly sticking supporting parts of the two metal sheets to enable the two metal sheets provided with the fiber bragg grating to form a sensor main body internally provided with the air bag, wherein temperature measuring metal wires on the surfaces of the temperature measuring metal sheets extend out of the sensor main body and are arranged outside, and the limiting rings in the middles of the metal rods at two ends are used for connecting a traction rope; the parts of the metal rods at the two ends, which extend out of the metal sheets, are knotted, the knotted parts are used for fixing the head and tail ends of the two metal sheets, and the circular ring part formed by knotting is used for connecting a torsion-resistant rope, and the torsion-resistant rope is used for balancing the torsion of the optical fiber;

s6: assembling the optical cable: manufacturing an optical fiber connector for connecting four groups of optical fibers, connecting a traction rope for tensile strength in the middle, symmetrically arranging connecting through holes of torsion-resistant ropes on two sides, connecting the four optical fibers and the traction rope with the optical fiber connector, and connecting the torsion-resistant ropes on two sides with corresponding parts of the optical fiber connector;

s7: packaging the sensor body and the optical cable: packaging the sensor main body, the four groups of optical fibers, the traction ropes and the metal rod to ensure that the inner air bag is not damaged, and packaging the four groups of optical fibers and the traction ropes to form an optical cable;

s8: and (3) balance measurement: measuring the floating balance capacity of the sensor main body by using an oil suspension method, and carrying out floating balance by using a method of increasing and decreasing the mass of an elastic body at the end part;

s9: and (3) integral packaging: packaging and sealing the sensor main body and the optical cable by using a film, and enabling the temperature measuring metal wire to extend outwards after penetrating through the sensor main body and the surface skin; a film compatible with oil is hung between the torsion-resistant rope and the optical cable, and torsion-resistant balance is performed by means of liquid flow.

2. The method for manufacturing and packaging a fish-type FBG pressure and temperature sensor as claimed in claim 1, wherein the connection length of the pulling rope is not greater than the length of the optical fiber between the optical fiber connector and the connection hole when the optical fiber cable is assembled in step S6 to prevent the optical fiber from being broken by the impact of liquid flow; in step S6, the length of the optical cable may be greater than ten times the longitudinal length of the sensor body or the optical fiber connector at the front end thereof, so as to avoid the influence of the rear turbulence of the upstream object on the pressure detection of the next sensor.

3. The method for manufacturing and packaging a fish-shaped fiber grating pressure and temperature sensor as claimed in claim 2, wherein the filling is performed during the assembly of the sensor body in step S5, and the filling is used to fill the two metal sheets and the cavity between the temperature measuring metal sheet and the air bag, so as to ensure the position of the air bag and the metal rod in the sensor body to be fixed, thereby forming a sensor body with a fish-like structure.

4. The method for manufacturing and packaging a fish-type FBG pressure and temperature sensor as claimed in claim 3, it is characterized in that after the step S7, the sensor is calibrated for pressure detection by a calibration method of every 0.1MPa from 0MPa, firstly, each pressure data is collected, correspondingly collecting the difference value of the drift amount of each grating center wavelength in the first optical fiber and the second optical fiber, storing the difference value of the drift amount of each fish-shaped sensor as the calibration relation of corresponding pressure, storing the calibration relation in a computer system for measuring the pressure by each fish-shaped sensor until the pressure P12 when the difference value of the drift amount of the center wavelength is not changed or the difference value of the drift amount of the center wavelength is not changed any more, after P12/1.2, the obtained data is used as the maximum pressure value Pmax which can be detected by the gratings on the first optical fiber and the second optical fiber of the female metal sheet of the sensor;

for the gratings on the third optical fiber and the fourth optical fiber, the information of the grating on the third optical fiber on the sensor can be collected and calibrated by a calibration method of every 1 ℃ from 10 ℃ to 100 ℃, meanwhile, in each temperature interval (10 ℃, 11 ℃, 12 ℃, 1.. 100 ℃), the grating signal on the fourth optical fiber is collected and the pressure calibration of the corresponding temperature value is carried out by the calibration method of boosting the pressure every 0.1MPa from the Pmax value, and when the highest pressure (for example, 45MPa) of a hydraulic system of the current engineering machinery is reached, the pressure signal collection of the grating on the fourth optical fiber under the temperature is completed; then, the temperature is raised by 1 ℃, the grating on the fourth optical fiber is calibrated to collect the pressure signal under the temperature according to the steps, finally, the temperature signal of the grating on the third optical fiber and the temperature data form a corresponding table, the temperature and pressure data formed by the temperature signal of the grating on the third optical fiber and the signal of the grating on the fourth optical fiber together form a corresponding net-shaped table, the state of the light source signal transmitted by the optical fiber and the corresponding relation between the pressure and the temperature and the parameters are stored in a computer system, and the pressure calibration of the fish-shaped sensor is completed.

5. The method for manufacturing and packaging a fish-type FBG pressure and temperature sensor as claimed in claim 4, wherein the film used in step S9 is a low temperature resistant polyethylene film.

6. The method for manufacturing and packaging a fish-type fiber grating pressure and temperature sensor according to claim 5, wherein the filler is selected from fluororubber or oil-resistant nitrile rubber, so as to take oil compatibility and working temperature range into consideration.

7. The method as claimed in claim 6, wherein the filler is vulcanized rubber or nylon material when the oil outside the sensor is under high pressure, so that the sensor has a matched elastic modulus.

8. The method for manufacturing and packaging a fish-type FBG pressure and temperature sensor as claimed in claim 7, wherein in step S4, when the air bag is manufactured, the skin material of the high-altitude balloon is used, low temperature resistant polyethylene (LDPE low density polyethylene) is selected, the skin material is heated and melted to a glass state in an inert gas environment, and the inert gas is filled by blowing a glass bottle to form the air bag with the inert gas inside.

9. The method for manufacturing and packaging a fish-type FBG pressure and temperature sensor as claimed in claim 7, wherein when the balloon is manufactured in step S4, the balloon is manufactured according to the manufacturing method of the balloon, the shape of the balloon is set to be spherical or symmetrical ellipsoid, and the surface of the balloon is coated with a lubricant incompatible with the filler.

10. The method for manufacturing and packaging a fish-type fiber grating pressure and temperature sensor according to claim 8 or 9, wherein the temperature grating sensitizer is an aluminum sheet, the temperature wire is a pure copper or silver material, and the positive metal sheet is an industrial titanium sheet or titanium alloy sheet or stainless steel sheet with a thickness of not less than 0.2 mm.

Background

The fiber grating is a diffraction grating formed by axially and periodically modulating the refractive index of a fiber core by a certain method, is a passive filter device, and is widely applied to the fields of fiber communication and sensing because the grating fiber has the advantages of small volume, low welding loss, full compatibility with fiber, embedding of intelligent materials and the like, and the resonant wavelength of the grating fiber is sensitive to changes of external environments such as strain, refractive index, concentration and the like. The common fiber grating has poor tensile and bending resistance under the naked condition, so that the packaging protection of the fiber grating is necessary, and because the temperature resistance of the fiber grating is poor, if the working temperature is higher than the heat-resistant temperature of the fiber grating, the central wavelength of the grating can generate large drift, so that the fiber grating passes through a calibration method of linear fitting, and the measuring range is limited.

At present, when the pressure or the temperature in a hydraulic pipeline is detected, a method of forming a detection process hole in the radial direction of the pipeline and installing a pressure or temperature sensor probe on the radial side wall of the pipeline is generally adopted, but the method has certain problems: firstly, damaging a pipeline side wall structure; secondly, the probe of the radial sensor destroys the laminar flow form of the liquid flow on the inner wall and increases the internal disturbance of the liquid flow; thirdly, the flow velocity inside and outside the spiral pipeline is different, the pressure state is different, and the method of adopting a fixed pressure sensor probe is difficult to accurately measure the pressure distribution and the change rule in the pipeline. Most of the liquid pressure measurement in the pipeline is carried out by using the fiber grating principle, but when the fiber grating pressure sensor is used for pressure measurement, the problems of small bearing capacity and small measurement pressure range exist. Therefore, at present, a cantilever beam amplification principle is generally adopted to package the pressure sensor so as to solve the problem of small bearing of the sensor, but the problem of increased volume of the sensor is also generated; and the problem that the range of the measured pressure is small cannot be solved by packaging the sensor, namely the range of the pressure sensor cannot meet the actual requirement of the engineering hydraulic machinery.

In addition, although the existing fiber grating temperature sensor can be connected with a plurality of sensors in series to realize distributed temperature measurement, 35 temperature sensors can be connected with a single optical fiber in series at most, wiring quantity is greatly reduced, and the fiber grating temperature sensor is simple, reliable and economical, but when the existing fiber grating temperature sensor is applied to an engineering structure, two problems exist, namely the problem of the strength of the fiber grating temperature sensor and the problem of time response, and the high strength inevitably causes large thickness of a packaging shell, so that the response speed to the environment temperature is influenced; in order to improve the response speed, the thickness of the packaging tube needs to be reduced, which reduces the protection strength, and in the prior art, the packaging structure of the fiber grating temperature sensor cannot have strong protection strength and fast response speed at the same time.

In the invention patent with the application number of CN201010141147.4 (a fiber grating temperature sensor), the packaging tube made of metal, glass or ceramic material is used for packaging, so that the fiber grating has strong protection strength; however, the grating senses the external ambient temperature of the packaging tube mainly by sensing the heat of the enclosed gas in the packaging tube, the grating is easily deformed by the expansion pressure of the internal gas at high temperature, and the internal heat dissipation speed is influenced to cause response delay when the ambient temperature is reduced.

Therefore, a detection system capable of realizing high-precision temperature and pressure distribution in a hydraulic pipe is needed, and is used for high-precision detection of oil temperature in the pipe and collection of nondestructive internal pressure data of multipoint pipe walls of the pipe.

Disclosure of Invention

The invention provides a method for manufacturing and packaging a fish-shaped fiber grating pressure and temperature sensor, which is characterized in that a fishbone-shaped metal sheet is designed according to the bionics principle of fish bodies, fiber grating sensors are arranged on the inner side and the outer side of the central axis of the metal sheet, the fiber grating sensors play a role of a strain diaphragm at low pressure, two optical fibers are arranged at the two sides of the longitudinal axis (equivalent to the thenar line of the fish body) of the metal sheet, and the positive and negative deformation principle of the two grating sensors is utilized to eliminate the temperature influence, so that the pressure detection of temperature self-compensation is realized; the characteristic of large-capacity high-speed operation of a computer is fully utilized, the problem that the detection range cannot be expanded due to information loss caused by a linear fitting method in sensor calibration is solved, the pressure detection range of the existing fiber grating sensor is expanded, the problems in the prior art are solved, a sub-symmetrical structure of a fish body is utilized, the temperature is transmitted to the wall of a sealed cavity arranged in a sensor main body through a beard-shaped temperature measurement metal wire protruding to the outer side at the other side, then the temperature is transmitted to a temperature measurement grating sensitization part through a partition plate on the wall of the sealed cavity and heat conduction silicon oil in the sealed cavity, and the fiber grating is fixed on the temperature measurement grating sensitization part, so that the timeliness of the fiber grating for collecting environmental temperature changes is enhanced, and the sensitivity coefficient of the fiber grating to temperature signals is improved; meanwhile, because the elastic modulus of the partition board and the cavity wall of the sealing cavity is far larger than the elastic modulus of the surrounding air bag and the elastic body sensor main body, the interference of the pressure strain outside the fish body on the longitudinal deformation of the grating on the temperature measurement grating sensitization piece in the temperature measurement metal sheet is greatly relieved, on the other hand, because only one arc-shaped cross section of the temperature measurement grating sensitization piece is fixedly connected with the partition board, even if the partition board has small deformation caused by external stress, the longitudinal deformation of the optical fiber pasted on the longitudinal axis of the arc-shaped tile-shaped temperature measurement grating sensitization piece is not influenced, thereby avoiding the interference of the external pressure on the longitudinal deformation of the grating on the temperature measurement grating sensitization piece in the temperature measurement metal sheet, further overcoming the cross interference of the deformation caused by the external stress on the longitudinal signal of the optical fiber grating for measuring the temperature, and furthermore, because only one end is fixed when the temperature measurement grating sensitization piece is longitudinally deformed, the other end is freely suspended, so that the cross interference of the deformation caused by the internal thermal stress caused by thermal expansion and cold contraction on the longitudinal signal of the fiber grating for measuring the temperature is overcome, and the high-precision detection of the fiber grating on the temperature is realized; finally, in order to fully utilize the information acquired by the temperature signal and expand the detection range of the fiber bragg grating groups on the two sides of the female metal sheet on the pressure, the fiber bragg grating on the outer side of the male metal sheet can be used for simultaneously detecting the pressure and the temperature data of the liquid in the pipeline, and the measurement of the fiber bragg grating on the outer side of the male metal sheet on the pressure is realized through the look-up table back calculation after the temperature data is acquired.

The technical scheme adopted by the invention for solving the technical problems is as follows: a method for manufacturing and packaging a fish-shaped fiber grating pressure and temperature sensor comprises the following steps:

s1: preparing fish-shaped metal sheets: punching the metal sheet into a fishbone shape, arranging connecting holes at two ends of the metal sheet, and punching the metal sheet into a streamline with a convex middle part; one metal sheet is symmetrically provided with longitudinal grooves along two sides of a longitudinal central axis of the metal sheet, and the longitudinal grooves are set as female metal sheets; taking another metal sheet, symmetrically forming rib grooves protruding outwards in the longitudinal direction along two sides of a longitudinal central axis, and setting the rib grooves as male surface metal sheets; the female metal sheet and the male metal sheet have the same quantity of bone spurs and are symmetrically arranged;

s2: manufacturing a temperature measuring unit:

manufacturing a temperature measuring metal sheet: punching a strip-shaped metal sheet into an arc shape along the longitudinal axis of the metal sheet, performing turned-up flanging shearing treatment, inserting a flanged edge obtained after shearing the metal sheet into the inner side position of a rib groove of the male metal sheet, ensuring that the longitudinal axis of the strip-shaped metal sheet is straight, forming a closed sealing cavity by the strip-shaped metal sheet and the rib groove of the male metal sheet, and setting the strip-shaped metal sheet as a temperature measuring metal sheet;

manufacturing a partition plate: taking at least two metal sheets, shearing the metal sheets into at least two partition plates according to the shapes of different cross sections of the central axis of the sealed cavity, shearing flow through holes at the edges of the partition plates, punching mounting holes in the middle of the partition plates, and arranging the partition plates at corresponding cross sections in the sealed cavity;

manufacturing a temperature measurement grating sensitization piece: punching another strip-shaped metal sheet into an arc shape along the longitudinal axis according to the size of the mounting hole in the middle of the partition plate, and performing turned-up edge shearing treatment on the metal sheet to enable the metal sheet to penetrate into the mounting hole in the middle of the partition plate and set the metal sheet as a temperature-measuring grating sensitizing piece; placing a temperature-measuring grating sensitizing piece in the mounting hole of the partition plate, wherein one end of the temperature-measuring grating sensitizing piece is fixedly connected with one of the partition plates, and the positions of the mounting holes of the other partition plates are abutted with the temperature-measuring grating sensitizing piece, so that the other end of the temperature-measuring grating sensitizing piece is arranged in a suspension manner;

manufacturing a temperature measuring metal wire: welding at least one temperature measuring metal wire on the outer surface of the temperature measuring metal sheet;

s3: manufacturing the fiber grating: selecting four same optical fibers, symmetrically pasting the optical fibers on the central axes of the inner side and the outer side of the female metal sheet respectively, engraving gratings with the same characteristic value on the surface of each optical fiber, ensuring that the gratings on the inner side and the outer side of the middle part of the female metal sheet are in the same characteristic grid period, numbering the optical fiber pasted on the outer side wall of the female metal sheet as a first optical fiber, and numbering the optical fiber pasted on the inner side wall of the female metal sheet as a second optical fiber;

taking one of the remaining two optical fibers as a third optical fiber, enabling the third optical fiber to penetrate through the temperature measurement grating sensitization part along the longitudinal axis direction of the sealed cavity and be adhered to the longitudinal axis position of the concave surface of the temperature measurement grating sensitization part, engraving a grating at the position where the third optical fiber is adhered to the temperature measurement grating sensitization part, wherein the grating characteristic value on the third optical fiber is the same as the grating characteristic value on the first or second optical fiber, and the two ends of the third optical fiber and the temperature measurement metal sheet are adhered to ensure that the third optical fiber in the sealed cavity is in a loose state, wherein the loose state comprises a loose ring arranged on the optical fiber; the slack loop comprises at least one circle of optical fiber winding;

manufacturing a temperature measurement sealing cavity: then sticking or welding the raised end of the temperature measurement metal sheet and the rib groove of the male surface metal sheet together, and sealing after filling a heat-conducting medium of fluid in the sealing cavity to completely seal the sealing cavity; adhering a fourth optical fiber to the central axis of the outer side of the male surface metal sheet, and engraving a grating on the surface of the fourth optical fiber at the middle position of the male surface metal sheet, wherein the grating characteristic values on the fourth optical fiber are the same as those on the third optical fiber;

s4: manufacturing an air bag: filling inert gas into the air bags by using a method of blowing the balloons, wherein the size of each batch of air bags is the same, and ensuring that the two metal sheets are not cracked when being compressed to a plane;

s5: assembling a sensor main body: placing the air bag at the concave position of the female metal sheet stuck with the fiber bragg grating, respectively placing two metal rods with limiting rings in the middle into connecting holes at two ends of the female metal sheet, penetrating corresponding holes of the male metal sheet into the other ends of the two metal rods, and correspondingly sticking supporting parts of the two metal sheets to enable the two metal sheets provided with the fiber bragg grating to form a sensor main body internally provided with the air bag, wherein temperature measuring metal wires on the surfaces of the temperature measuring metal sheets extend out of the sensor main body and are arranged outside, and the limiting rings in the middles of the metal rods at two ends are used for connecting a traction rope; the parts of the metal rods at the two ends, which extend out of the metal sheets, are knotted, the knotted parts are used for fixing the head and tail ends of the two metal sheets, and the circular ring part formed by knotting is used for connecting a torsion-resistant rope, and the torsion-resistant rope is used for balancing the torsion of the optical fiber;

s6: assembling the optical cable: manufacturing an optical fiber connector for connecting four groups of optical fibers, connecting a traction rope for tensile strength in the middle, symmetrically arranging connecting through holes of torsion-resistant ropes on two sides, connecting the four optical fibers and the traction rope with the optical fiber connector, and connecting the torsion-resistant ropes on two sides with corresponding parts of the optical fiber connector;

s7: packaging the sensor body and the optical cable: packaging the sensor main body, the four groups of optical fibers, the traction ropes and the metal rod to ensure that the inner air bag is not damaged, and packaging the four groups of optical fibers and the traction ropes to form an optical cable;

s8: and (3) balance measurement: measuring the floating balance capacity of the sensor main body by using an oil suspension method, and carrying out floating balance by using a method of increasing and decreasing the mass of an elastic body at the end part;

s9: and (3) integral packaging: packaging and sealing the sensor main body and the optical cable by using a film, and enabling the temperature measuring metal wire to extend outwards after penetrating through the sensor main body and the surface skin; a film compatible with oil is hung between the torsion-resistant rope and the optical cable, and torsion-resistant balance is performed by means of liquid flow.

Further, when the optical cable is assembled in step S6, the connection length of the pulling rope is not greater than the length of the optical fiber between the optical fiber connector and the connection hole, so as to prevent the optical fiber from being broken by the impact of liquid flow; in step S6, the length of the optical cable may be greater than ten times the longitudinal length of the sensor body or the optical fiber connector at the front end thereof, so as to avoid the influence of the rear turbulence of the upstream object on the pressure detection of the next sensor.

Further, filling is performed when the sensor main body is assembled in step S5, and the filler is used to fill the two metal sheets and the cavity between the temperature measurement metal sheet and the air bag, so as to ensure that the positions of the air bag and the metal rod in the sensor main body are fixed, thereby forming a sensor whole body with a fish-like structure.

Further, after the step S7 is performed with the integral packaging, the pressure detection calibration is performed on the sensors by a calibration method of every 0.1MPa from 0MPa, first, each pressure data is collected, the difference value of the central wavelength drift amounts of the gratings in the first optical fiber and the second optical fiber is correspondingly collected, the difference value of the drift amount of each fish-type sensor is stored as the calibration relation of the corresponding pressure, the calibration relation is stored in the computer system for measuring the pressure by each fish-type sensor until the pressure P12 when the difference value of the central wavelength drift amount is not present or the difference value of the central wavelength drift amount is not changed any more, and the data obtained after P12/1.2 is used as the maximum pressure value Pmax which can be detected by the gratings on the first optical fiber and the second optical fiber of the metal sheet of the female side of the sensor;

for the gratings on the third optical fiber and the fourth optical fiber, according to the requirements that the suitable temperature of the hydraulic oil of the engineering machinery is 35 ℃ to 60 ℃ and the minimum temperature of 20 ℃ is not more than 80 ℃, the gratings are used as sensors, the temperature of the hydraulic system is required to be heated when the temperature is lower than 20 ℃, at least 10 ℃ is required to be detected and the temperature is 100 ℃ for analyzing faults, the information of the gratings on the third optical fiber on the sensors is collected and calibrated by a calibration method at every 1 ℃, and simultaneously, in each temperature interval (10 ℃, 11 ℃, 12.... 100 ℃), starting from the Pmax value, acquiring grating signals on the fourth optical fiber by the calibration method of boosting every 0.1MPa and calibrating the pressure of a corresponding temperature value, when the highest pressure (for example, 45MPa) of a hydraulic system of the current engineering machinery is reached, the grating on the fourth optical fiber finishes the acquisition of the pressure signal at the temperature; then, the temperature is raised by 1 ℃, the grating on the fourth optical fiber is calibrated to collect the pressure signal under the temperature according to the steps, finally, the temperature signal of the grating on the third optical fiber and the temperature data form a corresponding table, the temperature and pressure data formed by the temperature signal of the grating on the third optical fiber and the signal of the grating on the fourth optical fiber together form a corresponding net-shaped table, the state of the light source signal transmitted by the optical fiber and the corresponding relation between the pressure and the temperature and the parameters are stored in a computer system, and the pressure calibration of the fish-shaped sensor is completed.

Further, the film used in step S9 is a low temperature resistant polyethylene film.

Furthermore, the filler is made of fluororubber or oil-resistant nitrile rubber, so that compatibility of oil and a working temperature range are both considered.

Further, when the oil outside the sensor is in a high-pressure state, the filler can be made of vulcanized rubber or nylon materials, so that the sensor has a matched elastic modulus.

Further, when the airbag is manufactured in step S4, the skin material of the high-altitude balloon is used, low-temperature resistant polyethylene (LDPE) is selected, the skin material is heated and melted to a glass state in an inert gas environment, and the inert gas is filled by blowing a glass bottle to form the airbag with the inert gas inside.

Further, when the airbag is manufactured in step S4, the airbag is manufactured according to the manufacturing method of the balloon, the outer shape of the airbag is spherical or symmetrical ellipsoidal, and a lubricant incompatible with the filler is sprayed on the surface of the airbag.

Furthermore, the temperature-measuring grating sensitization piece is an aluminum sheet, the temperature-measuring metal wire is a pure copper or pure silver material, and the positive metal sheet is an industrial titanium sheet or a titanium alloy sheet or a stainless steel sheet with the thickness not less than 0.2 mm.

The fish body temperature self-compensation pressure detection device has the advantages that according to the bionics principle of fish bodies, a fishbone-shaped metal sheet is designed, the fiber grating sensors are arranged on the inner side and the outer side of the central axis of the metal sheet, the fiber grating sensors play a role of a strain diaphragm when the pressure is low, two optical fibers are arranged on two sides of the longitudinal axis (equivalent to the thenar line of the fish body) of the metal sheet, and the temperature influence is eliminated by utilizing the positive and negative deformation principle of the two grating sensors, so that the pressure detection of temperature self-compensation is realized; the characteristic of large-capacity high-speed operation of a computer is fully utilized, the problem that the detection range cannot be expanded due to information loss caused by a linear fitting method in sensor calibration is solved, the pressure detection range of the existing fiber grating sensor is expanded, the problems in the prior art are solved, a sub-symmetrical structure of a fish body is utilized, the temperature is transmitted to the wall of a sealed cavity arranged in a sensor main body through a beard-shaped temperature measurement metal wire protruding to the outer side at the other side, then the temperature is transmitted to a temperature measurement grating sensitization part through a partition plate on the wall of the sealed cavity and heat conduction silicon oil in the sealed cavity, and the fiber grating is fixed on the temperature measurement grating sensitization part, so that the timeliness of the fiber grating for collecting environmental temperature changes is enhanced, and the sensitivity coefficient of the fiber grating to temperature signals is improved; meanwhile, because the elastic modulus of the partition board and the cavity wall of the sealing cavity is far larger than the elastic modulus of the surrounding air bag and the elastic body sensor main body, the interference of the pressure strain outside the fish body on the longitudinal deformation of the grating on the temperature measurement grating sensitization piece in the temperature measurement metal sheet is greatly relieved, on the other hand, because only one arc-shaped cross section of the temperature measurement grating sensitization piece is fixedly connected with the partition board, even if the partition board has small deformation caused by external stress, the longitudinal deformation of the optical fiber pasted on the longitudinal axis of the arc-shaped tile-shaped temperature measurement grating sensitization piece is not influenced, thereby avoiding the interference of the external pressure on the longitudinal deformation of the grating on the temperature measurement grating sensitization piece in the temperature measurement metal sheet, further overcoming the cross interference of the deformation caused by the external stress on the longitudinal signal of the optical fiber grating for measuring the temperature, and furthermore, because only one end is fixed when the temperature measurement grating sensitization piece is longitudinally deformed, the other end is freely suspended, so that the cross interference of the deformation caused by the internal thermal stress caused by thermal expansion and cold contraction on the longitudinal signal of the fiber grating for measuring the temperature is overcome, and the high-precision detection of the fiber grating on the temperature is realized; finally, in order to fully utilize the information acquired by the temperature signal and expand the detection range of the fiber bragg grating groups on the two sides of the female metal sheet on the pressure, the fiber bragg grating on the outer side of the male metal sheet can be used for simultaneously detecting the pressure and the temperature data of the liquid in the pipeline, and the measurement of the fiber bragg grating on the outer side of the male metal sheet on the pressure is realized through the look-up table back calculation after the temperature data is acquired.

Drawings

Fig. 1 is a schematic perspective view of a main body structure of a sensor according to the present invention.

Fig. 2 is a schematic top view of the main body structure of the sensor of the present invention.

FIG. 3 is a schematic side view of the main body structure of the sensor of the present invention.

FIG. 4 is a schematic sectional view of the assembled structure of the present invention.

FIG. 5 is a schematic view of a configuration of a plurality of sensors according to the present invention.

FIG. 6 is a schematic structural diagram of the optimized state of the male-side metal sheet according to the present invention.

FIG. 7 is a schematic structural diagram of the optimized state of the female metal sheet according to the present invention.

In the figure, 1, a female side metal sheet; 2. a rib groove; 3. a male-side metal sheet; 4. a cavity; 5. an air bag; 6. a filler; 7. a first optical fiber; 8. a second optical fiber; 9. measuring the temperature of the metal sheet; 10. sealing the cavity; 11. a partition plate; 12. a temperature measurement grating sensitization part; 13. a third optical fiber; 14. measuring the temperature of the metal wire; 15. a fourth optical fiber; 16. an optical fiber connector; 17. a gap; 18. a metal rod; 19. a hauling rope; 20. a torsion resistant rope; 21. a lateral groove; 22. a support portion; 23. an end groove; 24. and (4) a groove.

Detailed Description

In order to clearly explain the technical features of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced in other ways than those described herein, and therefore the scope of the present application is not limited by the specific embodiments disclosed below.

In addition, in the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", and the like, indicate orientations and positional relationships based on those shown in the drawings, are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

As shown in fig. 1-7, a method for manufacturing and packaging a fish-type fiber grating pressure and temperature sensor comprises the following steps:

s1: preparing fish-shaped metal sheets: punching the metal sheet into a fishbone shape, arranging connecting holes at two ends of the metal sheet, and punching the metal sheet into a streamline with a convex middle part; one metal sheet is symmetrically provided with longitudinal grooves along two sides of a longitudinal central axis of the metal sheet, and the longitudinal grooves are set as female metal sheets 1; taking another metal sheet, symmetrically forming rib grooves 2 protruding outwards in the longitudinal direction along two sides of a longitudinal central axis, and setting the rib grooves as male surface metal sheets 2; the female metal sheet 1 and the male metal sheet 3 have the same quantity of bone spurs and are symmetrically arranged;

in addition, the structure of the metal sheet can be further optimized, each metal sheet is provided with at least two side grooves 21, the side grooves 21 are symmetrically arranged about the longitudinal central axis of the metal sheet, and the parts left beside the side grooves 21 form a plurality of supporting parts 22 which are matched with each other; when the sensor body is subjected to liquid pressure, the supporting parts 22 corresponding to the two metal sheets can be mutually abutted so as to increase the overall elastic modulus of the sensor body;

s2: manufacturing a temperature measuring unit:

manufacturing a temperature measuring metal sheet: punching a strip-shaped metal sheet into an arc shape along the longitudinal axis of the metal sheet, performing turned-up flanging shearing treatment, inserting a flanged edge after the metal sheet is sheared into the inner side position of a rib groove 2 of a male metal sheet 3, ensuring that the longitudinal axis of the strip-shaped metal sheet is straight, forming a closed sealing cavity 10 by the strip-shaped metal sheet and the rib groove 2 of the male metal sheet 3, and setting the strip-shaped metal sheet as a temperature measuring metal sheet 9;

manufacturing a partition plate: taking at least two metal sheets, shearing the metal sheets into at least two partition plates 11 according to the shapes of different cross sections of the central axis of the sealed cavity 10, shearing flow through holes at the edges of the partition plates 11, punching mounting holes in the middle of the partition plates, and arranging the partition plates at corresponding cross sections in the sealed cavity 10;

manufacturing a temperature measurement grating sensitization piece: punching another strip-shaped metal sheet into an arc shape along the longitudinal axis according to the size of the mounting hole in the middle of the partition plate 11, and performing turned-up edge shearing treatment on the metal sheet to enable the metal sheet to penetrate into the mounting hole in the middle of the partition plate 11 and arranging the metal sheet as a temperature-measuring grating sensitizing piece 12; a temperature-measuring grating sensitizing piece 12 is placed in the mounting hole of the partition board 11, one end of the temperature-measuring grating sensitizing piece 12 is fixedly connected with one partition board 11, the mounting hole positions of other partition boards 11 are abutted with the temperature-measuring grating sensitizing piece 12, and the other end of the temperature-measuring grating sensitizing piece 12 is suspended;

manufacturing a temperature measuring metal wire: at least one temperature measuring metal wire 14 is welded on the outer surface of the temperature measuring metal sheet 9;

s3: manufacturing the fiber grating: selecting four same optical fibers, symmetrically pasting the optical fibers on the central axes of the inner side and the outer side of the female metal sheet 1 respectively, engraving gratings with the same characteristic value on the surface of each optical fiber, ensuring that the gratings on the inner side and the outer side of the middle part of the female metal sheet 1 are in the same characteristic grid period, numbering the optical fiber pasted on the outer side wall of the female metal sheet as a first optical fiber 7, and numbering the optical fiber pasted on the inner side wall of the female metal sheet 1 as a second optical fiber 8;

taking one of the remaining two optical fibers as a third optical fiber 13, enabling the third optical fiber 13 to penetrate through the temperature measurement grating sensitization part 12 along the longitudinal axis direction of the sealed cavity 10 and be adhered to the longitudinal axis position of the concave surface of the temperature measurement grating sensitization part 12, engraving a grating at the adhesion position of the third optical fiber 13 and the temperature measurement grating sensitization part 12, wherein the grating characteristic value on the third optical fiber is the same as the grating characteristic value on the first or second optical fiber, and the two ends of the third optical fiber 13 and the temperature measurement metal sheet 9 are adhered to ensure that the third optical fiber 13 in the sealed cavity 10 is in a loose state; the relaxed state comprises a fiber with a slack loop; a slack loop comprising at least one turn of optical fiber wrap;

manufacturing a temperature measurement sealing cavity: then sticking or welding the tilting end of the temperature measurement metal sheet 9 and the rib groove 2 of the male surface metal sheet 3 together, and sealing after filling the heat-conducting medium of the fluid in the sealing cavity 10 to completely seal the sealing cavity 10; a fourth optical fiber 15 is stuck to the central axis of the outer side of the male metal sheet 3, a grating is engraved on the surface of the fourth optical fiber 15 in the middle of the male metal sheet 3, and the characteristic values of the grating on the fourth optical fiber 15 are the same as those of the grating on the third optical fiber 13; it should be noted that, the sealed cavity 10 is filled with a heat conducting medium of 1/2 to 4/5, and the heat conducting medium is selected from heat conducting silicone oil or heat conducting silicone grease, so that the whole sealed cavity 10 can transfer temperature to the temperature measurement grating sensitizer 12 to form a temperature measurement sealed cavity, wherein the heat conducting medium inside the sealed cavity 10 is not filled, and the capacity of the heating medium is controlled within a range of 1/2 to 4/5, and on the premise of ensuring the heat conducting capacity, the deformation factor of the outer wall of the sealed cavity 10 is considered to absorb the influence of strain.

S4: manufacturing an air bag: filling inert gas into the air bags 5 by using a method of blowing the balloons, wherein the sizes of the air bags 5 in each batch are the same, and the two metal sheets are ensured not to be broken when being compressed to a plane;

s5: assembling a sensor main body: placing an air bag 5 at the concave position of a female metal sheet 1 stuck with the fiber bragg grating, respectively placing two metal rods 18 with limiting rings in the middle into connecting holes at two ends of the female metal sheet 1, penetrating corresponding holes of a male metal sheet 3 into the other ends of the two metal rods 18, and correspondingly sticking supporting parts of the two metal sheets 18 to enable the two metal sheets provided with the fiber bragg grating to form a sensor main body with the built-in air bag 5, extending temperature measuring metal wires 14 on the surface of a temperature measuring metal sheet 9 from the sensor main body to penetrate out of the sensor main body to be arranged outside, wherein the limiting rings in the middles of the metal rods 18 at two ends are used for connecting a traction rope 19; the parts of the metal rods 18 at the two ends, which extend out of the metal sheets, are knotted, the knotted parts are used for fixing the head and tail ends of the two metal sheets, the circular ring part formed by knotting is used for connecting the torsion-resistant rope 20, and the torsion-resistant rope 20 is used for balancing the torsion of the optical fiber;

it is worth mentioning that end grooves 23 are symmetrically arranged at two longitudinal ends of the two metal sheets, a gap 17 is formed between the parts left beside the end grooves 23, the middle connecting ring 18 can be abutted with the parts left beside the end grooves 23 of the two metal sheets, so that the minimum size of the gap 17 is not smaller than the diameter size of the optical fiber, as shown in fig. 3, notches are arranged at the two end positions of the metal sheets compared with other positions, when the whole sensor is subjected to external oil pressure and main body parts of the metal sheets are abutted with each other, the sizes of the gaps 17 at the two ends can be ensured to be larger than the diameter of the optical fiber, the two end positions of the two metal sheets can not be contacted with each other to extrude the optical fiber, and the safety of the optical fiber is protected;

s6: assembling the optical cable: manufacturing an optical fiber connector 16 for connecting four groups of optical fibers, connecting a traction rope 19 for tensile strength in the middle, symmetrically arranging connecting through holes of torsion-resistant ropes 20 on two sides, connecting the four optical fibers and the traction rope 19 with the optical fiber connector 16, and connecting the torsion-resistant ropes 20 on two sides with corresponding parts of the optical fiber connector 16; the metal rod 18 is connected with the torsion resistant rope 20 at the knotted position at both ends, so that the torsion resistant rope 20 is connected with the metal rod 18 of other sensors at the knotted position, thereby enhancing the connection stability between the adjacent sensors.

S7: packaging the sensor body and the optical cable: packaging the sensor main body, the four groups of optical fibers, the traction ropes and the metal rods to ensure that the inner air bag 5 is not damaged, and packaging the four groups of optical fibers and the traction ropes 19 to form an optical cable;

s8: and (3) balance measurement: measuring the floating balance capacity of the sensor main body by using an oil suspension method, and carrying out floating balance by using a method of increasing and decreasing the mass of an elastic body at the end part;

s9: and (3) integral packaging: the sensor main body and the optical cable are packaged and sealed by using a film, so that the temperature measuring metal wire 14 passes through the sensor main body and the surface skin and then extends outwards; a film compatible with oil is hung between the torsion-resistant rope and the optical cable, and torsion-resistant balance is performed by means of liquid flow.

The fiber grating temperature and pressure sensor is formed after integral packaging, the partition plate 11 is connected with the temperature measurement metal sheet 9, the heat of the temperature measurement metal wire 14 can be reliably transmitted to the temperature measurement grating sensitization part 12 through the temperature measurement metal sheet 9 and the partition plate 11, other parts of the temperature measurement grating sensitization part 12 can be suspended or movably connected on other partition plates 11, so that the temperature measurement grating sensitization part 12 is enabled to be free and flexibly deformed under the influence of temperature, the temperature measurement grating sensitization part 12 can simultaneously receive the heat transmitted by a heat-conducting medium and the partition plate 11, meanwhile, the partition plate 11 can also play a role of auxiliary support on the temperature measurement grating sensitization part 12, the temperature measurement grating sensitization part 12 is enabled to keep stable in posture, and the phenomenon that the detection precision of temperature measurement is influenced by the fact that the third optical fiber 13 shakes after external oil flows to disturb is avoided. The whole sensor is designed with a fishbone-shaped metal sheet according to the bionics principle of water pressure and temperature sensing of fish, fiber grating sensors are arranged on the inner side and the outer side of the central axis of the metal sheet and play a role of a strain diaphragm at low pressure, two optical fibers and fiber gratings which are symmetrically arranged inside and outside are arranged on the two sides of the longitudinal axis of the metal sheet (the thenar line), and the temperature influence is eliminated by utilizing the positive and negative deformation principle of the two optical gratings, so that the pressure detection of temperature self-compensation is realized; the characteristic of large-capacity high-speed operation of a computer is fully utilized, the problem that the detection range cannot be expanded due to information loss caused by a linear fitting method in sensor calibration is solved, the range of the detection pressure of the conventional fiber grating sensor is expanded, the problems in the prior art are solved, a sub-symmetrical structure of a fish body is utilized, the temperature is transmitted to a temperature measurement metal sheet 9 arranged in a sensor main body through a beard-shaped temperature measurement metal wire 14 protruding to the outer side at the other side, then the temperature is transmitted to a temperature measurement grating sensitization piece 12 through a partition plate 11 on the temperature measurement metal sheet 9 and heat conduction silicon oil in a sealed cavity, and the fiber grating is fixed on the temperature measurement grating sensitization piece 12, so that the timeliness of collecting the fiber grating for environment temperature change is enhanced, and the sensitivity coefficient of the fiber grating for temperature signals is improved; meanwhile, because the elastic modulus of the partition plate 11 and the wall of the sealed cavity is far larger than the elastic modulus of the surrounding air bag 5 and the elastic body sensor main body, the interference of the pressure strain outside the fish body on the longitudinal deformation of the grating on the temperature measurement grating sensitizing piece 12 in the temperature measurement metal sheet 9 is greatly relieved, on the other hand, because only one arc-shaped cross section of the temperature measurement grating sensitizing piece 12 is fixedly connected with the partition plate 11, even if the partition plate 11 has micro deformation due to external stress, the longitudinal deformation of the optical fiber pasted on the longitudinal axis of the arc tile-shaped temperature measurement grating sensitizing piece 12 is not influenced, so the interference of the external pressure on the longitudinal deformation of the grating on the temperature measurement grating sensitizing piece 12 in the temperature measurement metal sheet is avoided, the cross interference of the deformation caused by the external stress on the longitudinal signal of the optical fiber grating for measuring the temperature is overcome, and moreover, only one end of the temperature measurement grating sensitizing piece 12 is fixed when longitudinally deformed, the other end is freely suspended, so that the cross interference of the deformation caused by the internal thermal stress caused by thermal expansion and cold contraction on the longitudinal signal of the fiber grating for measuring the temperature is overcome, and the high-precision detection of the fiber grating on the temperature is realized; finally, in order to fully utilize the information acquired by the temperature signals and expand the detection range of the fiber bragg grating groups on the two sides of the female metal sheet 1 to the pressure, the fiber bragg grating on the outer side of the male metal sheet 3 can be used for simultaneously detecting the pressure and the temperature data of the liquid in the pipeline, and the measurement of the fiber bragg grating on the outer side of the male metal sheet 3 to the pressure is realized through the look-up table back calculation after the temperature data is acquired.

When the optical cable is assembled in step S6, the connection length of the pulling string 19 is not greater than the length of the optical fiber between the optical fiber connector 16 and the connection hole to prevent the optical fiber from being broken by the impact of the liquid flow; in step S6, the length of the fiber optic cable may be greater than ten times the longitudinal length of the sensor body or fiber optic connector 16 at the front end thereof, so as to avoid the influence of the rear turbulence of the upstream object on the pressure detection of the next sensor.

In step S5, the sensor body is filled, and the filler 6 is used to fill the cavities between the two metal sheets and the temperature-measuring metal sheet 9 and the air bag 5, so as to ensure that the positions of the air bag 5 and the metal rod 18 in the sensor body are fixed, thereby forming a sensor whole with a fish-like structure.

After the step S7 is performed with integral packaging, calibrating the pressure detection of the sensor by a calibration method of every 0.1MPa from 0MPa, first collecting each pressure data, correspondingly collecting the difference value of the central wavelength drift amounts of the gratings in the first optical fiber 7 and the second optical fiber 8, storing the difference value of the drift amount of each fish-type sensor as the calibration relation of the corresponding pressure, storing the calibration relation in a computer system for measuring the pressure by each fish-type sensor until the pressure P12 when the difference value of the central wavelength drift amount or the difference value of the central wavelength drift amount is not changed any more, and taking the data obtained after P12/1.2 as the maximum pressure value Pmax which can be detected by the gratings on the first optical fiber 7 and the second optical fiber 8 of the female metal sheet of the sensor;

for the gratings on the third optical fiber 13 and the fourth optical fiber 15, according to the requirements that the suitable temperature of the hydraulic oil of the engineering machinery is 35 ℃ to 60 ℃ and the minimum temperature of 20 ℃ is not more than 80 ℃, the gratings are used as sensors, the temperature is from 10 ℃ (the hydraulic system needs to be heated when the temperature is lower than 20 ℃, and at least 10 ℃ is detected to 100 ℃ (for analyzing faults), the information of the gratings on the third optical fiber 13 on the sensors is collected and calibrated by a calibration method of every 1 ℃, and simultaneously, in each temperature interval (10 ℃, 11 ℃, 12.... 100 ℃), starting from the Pmax value, the grating signal on the fourth optical fiber 15 is collected and the pressure calibration of the corresponding temperature value is carried out according to the calibration method of boosting every 0.1MPa, when the highest pressure (for example, 45MPa) of a hydraulic system of the current engineering machinery is reached, the grating on the fourth optical fiber finishes the acquisition of the pressure signal at the temperature; then, the temperature is raised by 1 ℃, the grating on the fourth optical fiber 15 is calibrated to collect the pressure signal at the temperature according to the steps, finally, the temperature signal of the grating on the third optical fiber 13 and the temperature data form a corresponding table, the temperature and pressure data formed by the temperature signal of the grating on the third optical fiber 13 and the signal of the grating on the fourth optical fiber 15 together form a corresponding net table, the state of the light source signal transmitted by the optical fiber and the corresponding relation between the pressure and the temperature and the parameters are stored in a computer system, and the pressure calibration of the fish-shaped sensor is completed.

The film used in step S9 is a low temperature resistant polyethylene film.

In a preferred embodiment, the filler 6 is made of fluororubber or oil-resistant nitrile rubber, so as to achieve compatibility of oil and working temperature range.

It will be appreciated that the filler may be a vulcanized rubber or nylon material to provide a matching modulus of elasticity for the sensor when the oil outside the sensor is under high pressure.

In step S4, when the airbag 5 is manufactured, the skin material of the high-altitude balloon is used, low-temperature resistant polyethylene (LDPE) is selected, the skin material is heated and melted to a glass state in an inert gas environment, and the inert gas is filled by blowing a glass bottle, so as to form the airbag with the inert gas inside.

When the airbag 5 is manufactured in step S4, the airbag 5 is manufactured according to the method of manufacturing a balloon, the outer shape of the airbag 5 is spherical or symmetrical ellipsoidal, and a lubricant incompatible with the filler is sprayed on the surface of the airbag 5.

It should be noted that the temperature-measuring grating sensitization piece 12 is an aluminum sheet, the temperature-measuring metal wire 14 is a pure copper or pure silver material, and the positive metal sheet 3 is an industrial titanium sheet, a titanium alloy sheet or a stainless steel sheet with the thickness not less than 0.2 mm.

It is worth mentioning that the female metal sheet 1 can be excavated with through grooves 24 along the upper and lower sides of the optical fiber, so that the female metal sheet 1 can be deformed and responded quickly at low pressure, the first optical fiber 7 is arranged on the outer side of the female metal sheet 1, and the second optical fiber 8 is arranged on the inner side; the gratings on the first optical fiber 7 and the second optical fiber 8 are combined together to be suitable for measuring the pressure of liquid in the pipeline, and the grating on the third optical fiber 13 is suitable for measuring the temperature of the liquid in the pipeline; the grating on the fourth optical fiber 15 is suitable for measuring the comprehensive value of the pressure and the temperature of the liquid in the pipeline, and the pressure is indirectly measured through the temperature detection of the grating on the third optical fiber 13; in addition, the calibration equipment can also perform a double check and check on the temperature value detected by the grating on the third optical fiber 13 under a given pressure.

During the use, as shown in figure 5, the sensors after a plurality of encapsulation are established ties each other through optic fibre and are set up, make a plurality of sensors form the composite state and use, and the grating in the outside is connected, and inboard grating connection is inboard, and the grating of homonymy is guaranteed to be in groups, and fiber connector sign is clear, and the order is regular.

The above-described embodiments should not be construed as limiting the scope of the invention, and any alternative modifications or alterations to the embodiments of the present invention will be apparent to those skilled in the art.

The present invention is not described in detail, but is known to those skilled in the art.