Diaphragm type optical fiber pressure sensor

Abstract

The utility model relates to the field of optical fiber pressure sensors, and provides a diaphragm type optical fiber pressure sensor, which comprises a shell, a pressure bin module and a waterproof joint, and is characterized in that an optical fiber grating adjusting structure and an optical fiber grating fixing structure are arranged in the shell; the fiber bragg grating fixing structure comprises a grating fixing end, an adjusting end fixing support, a first grating adjusting fixing end and a second grating adjusting fixing end, the grating fixing end is welded in the pressure bin module, the adjusting end fixing support is installed on the pressure bin module, one end of a fiber bragg grating is fixed to the grating fixing end, and the other end of the fiber bragg grating is fixed to the second grating adjusting fixing end; the adjusting end fixing support comprises a transverse plate, a first ring hole and a second ring hole, the first grating adjusting fixing end penetrates through the first ring hole and is fixed on the two sides of the first ring hole through fiber grating adjusting structures, and the second grating adjusting fixing end penetrates through the second ring hole and is fixed on the two sides of the second ring hole through fiber grating adjusting structures. The fiber bragg grating penetrates through the first grating adjusting fixing end and the second grating adjusting fixing end.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of optical fiber pressure sensor, especially to a diaphragm type optical fiber pressure sensor. BACKGROUND

[0002] The statements in this section merely provide background information related to the utility model and do not necessarily constitute the prior art.

[0003] With the development of optical fiber and optical fiber communication technology, optical fiber sensing technology is popular, wherein the optical fiber pressure sensor as a new type of sensor has the advantages of light weight, small size, strong stability, not affected by electromagnetic interference compared with the traditional pressure sensor technology, and the packaging method of the pressure sensor greatly affects the measurement accuracy of the sensor. The optical fiber grating needs to be coupled using a coupling agent during the process of being fixed to the grating fixed end, and then will be aged for a period of time, and the aging of the coupling agent will cause the optical fiber grating to shrink back; the strain fiber pre-tightening adjusting nut has a non-standard pre-tightening phenomenon, which will also cause the strain grating to shrink back; and then affect the test accuracy of the sensor. SUMMARY

[0004] In order to solve the technical problems existing in the background art, the utility model provides a diaphragm type optical fiber pressure sensor, which eliminates the influence of the optical fiber grating shrinkage during packaging, solves the optical polarization problem caused by the optical fiber pressure sensor grating glue coating, ensures that the optical fiber grating has a certain pre-tightening force after packaging is completed, and improves the test accuracy of the sensor.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0006] The utility model provides a diaphragm type optical fiber pressure sensor, which comprises: a pressure chamber module, a waterproof joint and a shell arranged between the pressure chamber module and the waterproof joint, an optical fiber grating adjusting structure and an optical fiber grating fixing structure are arranged in the shell, the optical fiber grating fixing structure comprises a grating fixed end, an adjusting end fixed support, a first grating adjusting fixed end and a second grating adjusting fixed end, the grating fixed end is welded in the pressure chamber module, the adjusting end fixed support is installed on the pressure chamber module, one end of the optical fiber grating is fixed on the grating fixed end, and the other end is fixed on the second grating adjusting fixed end.

[0007] The adjusting end fixed support comprises a horizontal plate, a first ring hole and a second ring hole, the first grating adjusting fixed end passes through the first ring hole and is fixed on both sides of the first ring hole through the optical fiber grating adjusting structure, the second grating adjusting fixed end passes through the second ring hole and is fixed on both sides of the second ring hole through the optical fiber grating adjusting structure, and the optical fiber grating penetrates through the first grating adjusting fixed end and the second grating adjusting fixed end.

[0008] Further, the pressure chamber module comprises a pressure joint, a pressure chamber connector and a pressure chamber, the pressure joint is embedded with the pressure chamber connector at one end, and the pressure chamber connector is embedded with the pressure chamber.

[0009] Further, the pressure chamber and the adjusting end fixing support are both provided with through holes, and the pressure chamber is connected with the adjusting end fixing support through fixing bolts.

[0010] Further, the through hole on the adjusting end fixing support is a threaded hole.

[0011] Further, the grating fixed end is welded in the inside of the pressure chamber.

[0012] Further, the adjusting end fixing support adopts an F-shaped integral forming structure, and the horizontal plate is provided with a first ring hole and a second ring hole arranged in parallel.

[0013] Further, the fiber grating adjusting structure comprises a first strain grating adjusting nut and a second strain grating adjusting nut, and the first strain grating adjusting nut and the second strain grating adjusting nut are fixed at two ends of the first grating adjusting fixed end.

[0014] Further, the fiber grating adjusting structure further comprises a first temperature grating adjusting nut and a second temperature grating adjusting nut, and the first temperature grating adjusting nut and the second temperature grating adjusting nut are fixed at two ends of the second grating adjusting fixed end.

[0015] Further, the second grating adjusting fixed end is externally provided with a waterproof joint, and the waterproof joint is fixed at one end of the shell.

[0016] Further, the strain grating is coupled between the grating fixed end and the first grating adjusting fixed end, the temperature grating is coupled between the first grating adjusting fixed end and the second grating adjusting fixed end, and the strain grating and the temperature grating are adhered to the fixed end through a coupling agent.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] The utility model discloses a secondary pre-tightening treatment to fiber grating, adjusts nut torque with torque wrench, standardizes packaging technology, eliminates fiber grating shrinkback influence, solves the problem of light polarization caused by fiber pressure sensor grating gluing, improves the measuring accuracy of the sensor. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings accompanying the specification provide further understanding of the utility model, and the illustrative embodiments of the utility model and the description thereof are used to explain the utility model, and do not constitute improper limitation on the utility model.

[0020] Figure 1The utility model discloses a diaphragm type optical fiber pressure sensor whole structure schematic diagram Figure 1 ;

[0021] Figure 2 The utility model discloses a diaphragm type optical fiber pressure sensor whole structure schematic diagram Figure 2 ;

[0022] Figure 3 The utility model discloses a diaphragm type optical fiber pressure sensor internal structure schematic view;

[0023] Figure 4 The utility model discloses a diaphragm type optical fiber pressure sensor sectional view;

[0024] Figure 5 The utility model discloses a diaphragm type optical fiber pressure sensor pressure connector structure schematic diagram;

[0025] Figure 6 The utility model discloses a diaphragm type optical fiber pressure sensor pressure chamber connector structure schematic diagram;

[0026] Figure 7 The utility model discloses a diaphragm type optical fiber pressure sensor adjusting end fixed support structure schematic diagram;

[0027] Figure 8 The utility model discloses a diaphragm type optical fiber pressure sensor first grating adjusting fixed end / second grating adjusting fixed end structure schematic diagram;

[0028] Wherein, 1, pressure connector;2, pressure chamber connector;3, pressure chamber;4, fixed bolt;5, grating fixed end;6, fiber grating;7, adjusting end fixed support;8, first grating adjusting fixed end;9, first strain grating adjusting nut;10, second strain grating adjusting nut;11, first temperature grating adjusting nut;12, second temperature grating adjusting nut;13, second grating adjusting fixed end, 14, shell, 15, waterproof connector, 16, pressure chamber module, 17, fiber grating fixed structure, 18, fiber grating adjusting structure, 19, second ring hole, 20, first ring hole, 21, cross plate. DETAILED DESCRIPTION

[0029] The utility model will be further described below in connection with the drawings and examples.

[0030] It should be noted that the following detailed description is exemplary and is intended to provide further description of the utility model. Unless otherwise specified, all technical and scientific terms used in this paper have the same meaning as that generally understood by ordinary skilled persons in the technical field to which the utility model belongs.

[0031] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0032] Embodiment One

[0033] As shown in Figure 1 , Figure 2 , the embodiment provides a diaphragm type fiber optic pressure sensor, comprising: a pressure chamber module 16, a fiber grating fixing structure 17, a fiber grating adjusting structure 18, a fiber grating 6, an outer shell 14 and a waterproof joint 15.

[0034] The pressure chamber module 16 is fixed to one end of the adjusting end fixed support 7 in the fiber grating adjusting structure 18.

[0035] As shown in Figure 3 , one end of the fiber grating fixing structure 17 is fixed inside the pressure chamber 3 in the pressure chamber module 16, and the other end is fixed to the adjusting end fixed support 7 in the fiber grating adjusting structure 18.

[0036] The fiber grating adjusting structure 18 is connected with the pressure chamber module 16.

[0037] The fiber grating fixing structure 17 includes a grating fixed end 5, an adjusting end fixed support 7, a first grating adjusting fixed end 8 and a second grating adjusting fixed end 13.

[0038] As shown in Figure 4 , the fiber grating adopts a double grating structure, which is divided into a strain grating and a temperature grating. The strain grating is fixed between the grating fixed end 5 and the first grating adjusting fixed end 8, and the temperature grating is fixed between the first grating adjusting fixed end 8 and the second grating adjusting fixed end 13.

[0039] In some possible embodiments, the fiber grating adjusting structure 18 includes a first strain grating adjusting nut 9, a second strain grating adjusting nut 10, a first temperature grating adjusting nut 11 and a second temperature grating adjusting nut 12, and the pre-tightening of the fiber grating is adjusted by the adjusting nuts.

[0040] In one embodiment, as shown in Figure 7As shown, the first grating adjustment fixed end 8 and the second grating adjustment fixed end 13 are fixed on the upper part of the adjustment end fixed support 7 in the fiber grating adjustment structure 18. The adjustment end fixed support 7 comprises a horizontal plate 21, a first ring hole 20 and a second ring hole 19, the first ring hole 20 and the second ring hole 19 are installed on the horizontal plate 21, and the adjustment end fixed support 7 is an integral "F" type structure.

[0041] In a specific embodiment, the first grating adjustment fixed end 8 passes through the first ring hole 20 and is fixed on both sides of the first ring hole 20 by the first strain grating adjustment nut 9 and the second strain grating adjustment nut 10; the second grating adjustment fixed end 13 passes through the second ring hole 19 and is fixed on both sides of the second ring hole 19 by the first temperature grating adjustment nut 11 and the second temperature grating adjustment nut 12; the fiber grating passes through the first grating adjustment fixed end 8 and the second grating adjustment fixed end 13.

[0042] In some embodiments, as shown in Figure 8 As shown, the first grating adjustment fixed end 8 and the second grating adjustment fixed end 13 are provided with external threads matched with the first strain grating adjustment nut 9, the second strain grating adjustment nut 10, the first temperature grating adjustment nut 11 and the second temperature grating adjustment nut 12.

[0043] In some embodiments, the shell 14 is fixed at one end of the pressure chamber module 16.

[0044] The waterproof joint 15 is fixed at one end of the shell 14.

[0045] In some embodiments, the pressure chamber module 16 comprises a pressure joint 1, a pressure chamber connecting head 2, a pressure chamber 3 and a fixing bolt 4.

[0046] As shown in Figure 5 The pressure joint 1 adopts a quick joint.

[0047] As shown in Figure 6 The pressure chamber connecting head 2 is connected to the pressure joint 1 at one end and to the pressure chamber 3 at the other end.

[0048] The pressure chamber 3 and the adjustment end fixed support 7 are both provided with through holes, and the through hole on the adjustment end fixed support 7 is a threaded hole, and the pressure chamber 3 is connected to the adjustment end fixed support 7 by the fixing bolt 4.

[0049] Specifically, the adjustment end fixed support 7 and the pressure chamber 3 are connected by an internal hexagonal combination bolt, and the internal hexagonal bolt is tightened by a torque screwdriver.

[0050] In some possible embodiments, the grating fixed end 5 is welded inside the pressure chamber 3.

[0051] After the tightening, the coupling of the fiber grating 6 is carried out, the strain grating is coupled between the grating fixed end 5 and the first grating adjusting fixed end 8, the temperature grating is coupled between the first grating adjusting fixed end 8 and the second grating adjusting fixed end 13, and after the grating is coupled, aging is carried out, the purpose is to accelerate the solidification of the coupling agent. Then the pre-tightening of the grating is carried out, the pre-tightening method of the strain grating is that: the jumper wire is welded at the fiber outlet end of the sensor, the jumper wire is connected to the demodulator, the initial wavelength of the sensor is observed, the second strain grating adjusting nut 10 is screwed by the wrench to the pre-tightening state, and then the first strain grating adjusting nut 9 is screwed, the pre-tightening amount of the wavelength can be increased by screwing the second strain grating adjusting nut 10, the pre-tightening amount of the wavelength can be reduced by screwing the first strain grating adjusting nut 9, the change of the strain wavelength of the demodulator is observed during the adjustment, so that it is maintained within the required range, the torque value of the adjusting torque wrench is adjusted, and the first strain grating adjusting nut 9, the second strain grating adjusting nut 10, the first temperature grating adjusting nut 11 and the second temperature grating adjusting nut 12 are tightened in turn. The data of the demodulator is observed, and the strain wavelength is maintained within the required range.

[0052] After the wavelength of the sensor is adjusted, the packaging of the sensor is carried out, the pressure chamber 3 is connected with the pressure chamber connecting head 2, the shell 14 is installed, the sensor is placed in the high-temperature and low-temperature box to carry out high-temperature and low-temperature experiments, the temperature coefficient is obtained, the temperature grating can perform temperature compensation on the test value, then the sensor is installed on the pressure tooling, multiple pressure and zero reset operations are carried out, the change amount of the wavelength is recorded, and the test value is stabilized in the required range.

[0053] The working principle of the diaphragm type fiber optic pressure sensor is that when the pressure chamber 3 is subjected to external pressure, the pressure will act on the thin-walled end on the right side of the pressure chamber 3, and under the action of the pressure, the thin-walled end of the pressure chamber generates convex deformation, and the direction is from left to right. When the force is transmitted to the grating fixed end 5 fixed on the pressure chamber 3, the grating fixed end 5 will be subjected to a right pulling force, the strain grating will be displaced to the right, the corresponding strain wavelength will be reduced, the temperature grating is used to eliminate the influence of temperature on the test value, and the test pressure value is calculated according to the existing method.

[0054] The thickness of the diaphragm inside the pressure chamber 2 will affect the accuracy and range of the sensor, which is specifically manifested as: the yield stress of the diaphragm increases with the increase of the diaphragm thickness, the range of the sensor increases, the accuracy of the sensor increases with the decrease of the diaphragm thickness.

[0055] The traditional membrane type fiber pressure sensor grating coupling is bonded on the surface of the mechanical part through the coupling agent, which causes the fiber grating to appear chirp phenomenon, affects the full range of strain wavelength change, causes the change to be too small, and further affects the measurement accuracy of the sensor. Therefore, the packaging process of the grating is modified, the fiber at one end of the strain grating is bonded to the grating fixed end 5, the other end of the strain fiber is bonded to the first grating adjusting fixed end 8, the fiber at one end of the temperature grating is bonded to the first grating adjusting fixed end 8, the other end of the fiber is bonded to the second grating adjusting fixed end 13, and the state of the strain grating and the temperature grating is completely suspended, which eliminates the chirp phenomenon of the fiber grating, solves the light polarization problem caused by the fiber pressure sensor grating glue coating, and improves the measurement accuracy of the sensor.

[0056] The utility model discloses a diaphragm type fiber pressure sensor, through the secondary pre-tightening treatment of fiber grating, adjusts the nut torque with a torque wrench, standardizes the packaging process, and eliminates the influence of fiber grating retraction.

[0057] The utility model discloses the packaging process of fiber pressure sensor, and the process of no glue in grating area solves the chirp phenomenon of fiber grating.

[0058] The above only is the preferred embodiment of the utility model and does not limit the utility model, and the utility model can have various changes and changes for the person skilled in the art. Any modification, equivalent replacement, improvement etc. in the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A diaphragm-type optical fiber pressure sensor, comprising: The pressure chamber module (16) and the waterproof joint (15), and the shell (14) arranged between the pressure chamber module (16) and the waterproof joint (15) are characterized in that; The shell (14) is internally provided with a fiber grating adjusting structure (18) and a fiber grating fixing structure (17), the fiber grating fixing structure (17) comprises a grating fixing end (5), an adjusting end fixing support (7), a first grating adjusting fixing end (8) and a second grating adjusting fixing end (13), the grating fixing end (5) is welded inside the pressure chamber module (16), the adjusting end fixing support (7) is mounted on the pressure chamber module (16), one end of the fiber grating is fixed on the grating fixing end (5), and the other end of the fiber grating is fixed on the second grating adjusting fixing end (13); The adjusting end fixing support (7) comprises a horizontal plate, a first ring hole and a second ring hole, the first grating adjusting fixing end (8) passes through the first ring hole and is fixed on both sides of the first ring hole through the fiber grating adjusting structure (18), the second grating adjusting fixing end (13) passes through the second ring hole and is fixed on both sides of the second ring hole through the fiber grating adjusting structure (18), and the fiber grating penetrates through the first grating adjusting fixing end (8) and the second grating adjusting fixing end (13).

2. The diaphragm optical fiber pressure sensor of claim 1, wherein, The pressure chamber module (16) comprises a pressure joint (1), a pressure chamber connecting head (2) and a pressure chamber (3), the pressure joint (1) is internally embedded with the pressure chamber connecting head (2), and the pressure chamber connecting head (2) is internally embedded with the pressure chamber (3).

3. The diaphragm optical fiber pressure sensor of claim 2, wherein, The pressure chamber (3) and the adjusting end fixing support (7) are both provided with through holes, and the pressure chamber (3) is connected with the adjusting end fixing support (7) through a fixing bolt (4).

4. The diaphragm optical fiber pressure sensor of claim 3, wherein, The through hole on the adjusting end fixing support (7) is a threaded hole.

5. The diaphragm optical fiber pressure sensor of claim 1, wherein, The grating fixing end (5) is welded inside the pressure chamber (3).

6. The diaphragm optical fiber pressure sensor of claim 1, wherein, The adjusting end fixing support (7) adopts an F-shaped one-piece forming structure, and the horizontal plate is provided with the first ring hole and the second ring hole arranged in parallel.

7. The diaphragm optical fiber pressure sensor of claim 1, wherein, The fiber grating adjusting structure (18) comprises a first strain grating adjusting nut (9) and a second strain grating adjusting nut (10), and the first strain grating adjusting nut (9) and the second strain grating adjusting nut (10) are fixed at two ends of the first grating adjusting fixing end (8).

8. The diaphragm optical fiber pressure sensor of claim 1, wherein, The fiber grating adjusting structure (18) further comprises a first temperature grating adjusting nut (11) and a second temperature grating adjusting nut (12), and the first temperature grating adjusting nut (11) and the second temperature grating adjusting nut (12) are fixed at two ends of the second grating adjusting fixing end (13).

9. The diaphragm optical fiber pressure sensor of claim 1, wherein, The second grating adjusting fixing end (13) is externally sleeved with the waterproof joint (15), and the waterproof joint (15) is fixed at one end of the shell (14).

10. The diaphragm optical fiber pressure sensor of claim 1, wherein, The strain grating is coupled between the grating fixing end (5) and the first grating adjusting fixing end (8), the temperature grating is coupled between the first grating adjusting fixing end (8) and the second grating adjusting fixing end (13), and the strain grating and the temperature grating are both adhered to the fixing end through a coupling agent.

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