Filling and sealing method for fiber bragg grating temperature sensor

Abstract

The invention relates to a fiber bragg grating temperature sensor potting method, and belongs to the technical field of optical fiber sensing. The glue injection barrel is axially, vertically and fixedly mounted on the glue sealing table; the needle plugging cap is mounted on the needle of the glue injection cylinder; a metal funnel is mounted above the glue injection barrel; the glue solution flows into the inner cavity of the glue injection barrel below through the metal funnel; carrying out vacuumizing and defoaming treatment on the glue injection barrel filled with the glue solution; horizontally mounting a to-be-packaged fiber grating temperature sensor shell on a mobile platform of a glue injection table; the glue injection barrel subjected to vacuum defoaming is vertically installed on a glue dispensing machine of a glue injection table; injecting the glue solution into the shell of the fiber grating temperature sensor to be packaged under the control of a dispensing machine; and curing the shell of the fiber grating temperature sensor injected with the glue solution to complete packaging. According to the invention, the problem of low measurement precision caused by small-batch production of glue solution bubbles in sensors is solved, the problems of product consistency and repeatability caused by uncontrolled glue solution dosage are solved, and small-batch production is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of optical fiber sensing and relates to a potting method for an optical fiber Bragg grating temperature sensor. Background Art

[0002] The fiber Bragg grating temperature sensor has a serial structure, and multiple sensors are connected and signals are transmitted through a single optical fiber. Compared with thermocouples and platinum resistance sensors, it is light in weight and has strong anti-electromagnetic interference capabilities. It is an ideal temperature sensor to replace thermocouples and platinum resistance sensors on satellites and spacecraft. It can significantly reduce the weight of the original sensor while effectively increasing the payload weight.

[0003] To ensure uniform temperature transfer to the grating area while maintaining its ability to expand and contract freely within the metal shell, a flexible thermally conductive material, such as thermal grease, is typically placed around the grating area as a heat transfer medium. However, flexible filling materials are unstable in their operating environments and are easily affected by mechanical influences, leading to instability. Therefore, research into packaging methods that achieve long-term stable sensor performance is imperative. Summary of the Invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the existing technology, propose a fiber Bragg grating temperature sensor potting method, solve the problem of low measurement accuracy caused by bubbles in the glue in the sensor during small-batch production, solve the problem of product consistency and repeatability caused by uncontrolled glue dosage, and realize small-batch production.

[0005] The solution of the present invention is:

[0006] A fiber Bragg grating temperature sensor potting method, comprising:

[0007] Install the glue injection cylinder vertically on the glue sealing table; the needle of the glue injection cylinder points downward;

[0008] Install the needle blocking cap onto the needle of the injection barrel;

[0009] Install the metal funnel on top of the glue injection cylinder;

[0010] Pour the prepared glue into the metal funnel, and the glue flows into the inner cavity of the glue injection cylinder below through the metal funnel;

[0011] Remove the glue injection cylinder filled with glue from the sealing table, and perform vacuum and degassing treatment to remove the air in the glue;

[0012] The fiber Bragg grating temperature sensor housing to be packaged is horizontally mounted on the movable platform of the glue injection station;

[0013] Install the glue injection cylinder after vacuum degassing vertically on the glue dispensing machine on the glue injection table;

[0014] Remove the needle plugging cap and inject glue into the housing of the fiber Bragg grating temperature sensor to be packaged through the glue dispenser;

[0015] The fiber Bragg grating temperature sensor shell injected with glue is cured to complete the packaging.

[0016] In the above-mentioned fiber Bragg grating temperature sensor potting method, two fixing rings are provided on the sealing platform, and the two fixing rings are coaxially arranged up and down; wherein, the fixing ring located at the bottom fixes the glue injection cylinder; and the fixing ring located at the top fixes the metal funnel.

[0017] In the above-mentioned fiber Bragg grating temperature sensor potting method, the needle plugging cap is made of silicone rubber material; the needle plugging cap is used to seal the glue liquid in the glue injection cylinder.

[0018] In the above-mentioned fiber Bragg grating temperature sensor potting method, a vacuum degassing machine is used to perform vacuuming and degassing treatment on the glue injection cylinder filled with glue liquid; the vacuum degassing machine has vacuuming and centrifugal functions.

[0019] In the above-mentioned fiber Bragg grating temperature sensor potting method, during the process of the glue liquid flowing into the glue injection cylinder below through the metal funnel, the viscosity of the glue liquid is measured by the metal funnel.

[0020] In the above-mentioned fiber Bragg grating temperature sensor potting method, the glue is optical epoxy glue; the glue is cured at room temperature or high temperature; the room temperature curing temperature is 15°C-25°C; the high temperature curing temperature is 150°C-200°C.

[0021] In the above-mentioned fiber Bragg grating temperature sensor potting method, the movable platform realizes movement in the X and Y directions on the horizontal plane; the glue dispenser realizes movement of the glue injection cylinder in the vertical Z direction.

[0022] In the above-mentioned fiber Bragg grating temperature sensor potting method, the glue dispensing machine realizes quantitative glue injection of glue by setting the glue injection pressure and the glue injection time.

[0023] In the above-mentioned fiber Bragg grating temperature sensor potting method, the size of the glue injection area of ​​the fiber Bragg grating temperature sensor housing is 1.5 mm×20 mm.

[0024] In the above-mentioned fiber Bragg grating temperature sensor potting method, the glue injection portion of the fiber Bragg grating temperature sensor housing is in a straightened and stressed state.

[0025] The beneficial effects of the present invention compared with the prior art are:

[0026] (1) The present invention realizes the sealing of the needle of the glue injection cylinder by using a needle blocking cap, and realizes the vacuum degassing of the glue liquid by the vacuum pumping function and centrifugal function of the vacuum degassing machine;

[0027] (2) The present invention achieves the stability of the sensor state by injecting optical epoxy glue, rather than an unstable state;

[0028] (3) The present invention solves the problems of product consistency and repeatability caused by uncontrolled glue liquid dosage; realizes the cycle and batch production of glue injection work, and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the glue injection cylinder and the metal funnel of the present invention being installed on the glue sealing platform;

[0030] Figure 2 This is a schematic diagram of the glue injection of the present invention;

[0031] Figure 3 This is a schematic diagram of the glue injection area of ​​the fiber Bragg grating temperature sensor housing of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the embodiments.

[0033] This invention provides a fiber Bragg grating temperature sensor potting method that achieves quantitative control of glue injection by adjusting the injection pressure and application time of a glue dispenser. This method solves the problem of low measurement accuracy caused by glue bubbles in the glue during small-batch production. It also addresses the challenges of product consistency and repeatability caused by uncontrolled glue dosage, enabling small-batch production.

[0034] The fiber Bragg grating temperature sensor potting method specifically includes the following steps:

[0035] like Figure 1 As shown, the glue injection cylinder 1 is axially and vertically fixedly installed on the glue sealing platform 4; the needle of the glue injection cylinder 1 points downward.

[0036] The needle blocking cap 2 is installed on the needle of the glue injection barrel 1. The needle blocking cap 2 is made of silicone rubber material; the glue liquid in the glue injection barrel 1 is sealed by the needle blocking cap 2.

[0037] The metal funnel 3 is installed above the glue injection cylinder 1.

[0038] The sealing platform 4 of the present invention is provided with two fixing rings, which are coaxially arranged up and down. The fixing ring located at the bottom fixes the glue injection cylinder 1 , and the fixing ring located at the top fixes the metal funnel 3 .

[0039] The prepared glue is poured into the metal funnel 3, and the glue flows into the inner cavity of the glue injection cylinder 1 below through the metal funnel 3. During the process of the glue flowing into the glue injection cylinder 1 below through the metal funnel 3, the viscosity of the glue is measured by the metal funnel 3.

[0040] The glue injection cylinder 1 filled with glue liquid is removed from the glue sealing platform 4 and vacuumed and degassed to remove the air in the glue liquid. The glue injection cylinder 1 filled with glue liquid is vacuumed and degassed using a vacuum degassing machine; the vacuum degassing machine has vacuuming and centrifugal functions.

[0041] like Figure 2 As shown, the fiber Bragg grating temperature sensor housing 8 to be packaged is horizontally mounted on the movable platform 6 of the glue injection station 5. The movable platform 6 can move in the X and Y directions on the horizontal plane; the glue dispenser 7 can drive the glue injection cylinder 1 to move in the vertical Z direction.

[0042] The glue injection cylinder 1 after vacuum degassing is vertically mounted on the glue dispensing machine 7 of the glue injection platform 5 .

[0043] The needle plugging cap 2 is removed, and the glue liquid is injected into the housing 8 of the fiber Bragg grating temperature sensor to be packaged through the glue dispenser 7 .

[0044] The glue dispenser 7 realizes quantitative glue injection by setting the glue injection pressure and glue injection time. The glue injection area size of the fiber optic Bragg grating temperature sensor housing 8 is 1.5mm×20mm. Figure 3 The glue injection portion of the fiber Bragg grating temperature sensor housing 8 is in a stretched and stressed state.

[0045] The fiber Bragg grating temperature sensor housing 8 injected with glue is cured to complete the packaging. The glue is optical epoxy glue; the glue can be cured at room temperature or high temperature; the room temperature curing temperature is 15°C-25°C; the high temperature curing temperature is 150°C-200°C.

[0046] To ensure uniform temperature transfer to the grating area while maintaining its ability to expand and contract freely within the metal shell, a flexible thermally conductive material, such as thermal grease, is typically placed around the grating area as a heat transfer medium. However, flexible filling materials are unstable in their operating environments and are easily affected by mechanical influences, leading to instability. Therefore, research into packaging methods that achieve long-term stable sensor performance is imperative.

[0047] The feature of the present invention is that the grating and the metal shell are in a parallel state, and the expansion and contraction of the metal shell determines the expansion and contraction of the grating area, which provides conditions for encapsulating the grating area with epoxy glue.

[0048] Designed to eliminate bubbles within the potting compound, the optimal degassing solution was selected, integrating both vacuum degassing and centrifugal degassing processes to maximize degassing effectiveness. The injection process can be fully automatic, semi-automatic, or manual. Semi-automatic injection was selected based on production requirements, and quantitative control of the amount of glue can be achieved by setting the injection time and pressure.

[0049] The present invention achieves bubble-free potting and packaging of fiber Bragg grating temperature sensors. It also enables quantitative control of potting adhesive volume, ensuring product consistency and reliability. It also achieves standardization of the potting process for fiber Bragg grating temperature sensors.

[0050] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solutions of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A method for potting a fiber Bragg grating temperature sensor, characterized in that: include: The glue injection cylinder (1) is fixedly mounted axially and vertically on the glue sealing platform (4); the needle of the glue injection cylinder (1) points downward; Installing the needle blocking cap (2) onto the needle of the injection cylinder (1); Install the metal funnel (3) above the glue injection cylinder (1); Pour the prepared glue into the metal funnel (3), and the glue flows into the inner cavity of the glue injection cylinder (1) below through the metal funnel (3); The glue injection cylinder (1) filled with glue liquid is removed from the glue sealing platform (4), and vacuumed and degassed to remove the air in the glue liquid; The fiber Bragg grating temperature sensor housing (8) to be packaged is horizontally mounted on the movable platform (6) of the glue injection station (5); The glue injection cylinder (1) after vacuum degassing is vertically mounted on the glue dispensing machine (7) of the glue injection platform (5); The needle plugging cap (2) is removed, and the glue liquid is injected into the housing (8) of the fiber optic Bragg grating temperature sensor to be packaged by controlling the glue dispenser (7); The fiber optic Bragg grating temperature sensor housing (8) injected with glue is solidified to complete the packaging.

2. The method for potting a fiber Bragg grating temperature sensor according to claim 1, wherein: The sealing platform (4) is provided with two fixing rings, which are coaxially arranged up and down; wherein the fixing ring located at the bottom fixes the glue injection cylinder (1); and the fixing ring located at the top fixes the metal funnel (3).

3. The method for potting a fiber Bragg grating temperature sensor according to claim 1, wherein: The needle blocking cap (2) is made of silicone rubber material; the needle blocking cap (2) is used to seal the glue liquid in the glue injection cylinder (1).

4. The method for potting a fiber Bragg grating temperature sensor according to claim 3, wherein: A vacuum degassing machine is used to perform vacuuming and degassing treatment on a glue injection cylinder (1) filled with glue liquid; the vacuum degassing machine has vacuuming and centrifugal functions.

5. The method for potting a fiber Bragg grating temperature sensor according to claim 1, wherein: When the glue liquid flows into the glue injection cylinder (1) below through the metal funnel (3), the viscosity of the glue liquid is measured through the metal funnel (3).

6. The method for potting a fiber Bragg grating temperature sensor according to claim 1, wherein: The adhesive is an optical epoxy adhesive; the curing method of the adhesive is room temperature curing or high temperature curing; the room temperature curing temperature is 15°C-25°C; the high temperature curing temperature is 150°C-200°C.

7. The potting method of a fiber Bragg grating temperature sensor according to claim 1, characterized in that: The movable platform (6) realizes movement in the X direction and the Y direction on the horizontal plane; the glue dispenser (7) realizes driving the glue injection cylinder (1) to move in the vertical Z direction.

8. The method for potting a fiber Bragg grating temperature sensor according to claim 7, wherein: The glue dispensing machine (7) realizes quantitative glue injection of glue liquid by setting glue injection air pressure and glue injection time.

9. The method for potting a fiber Bragg grating temperature sensor according to claim 8, wherein: The size of the glue injection area of ​​the fiber Bragg grating temperature sensor housing (8) is 1.5 mm×20 mm.

10. The fiber Bragg grating temperature sensor potting method according to claim 9, characterized in that: The glue injection portion of the fiber optic Bragg grating temperature sensor housing (8) is in a straightened and stressed state.

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