Optical fiber penetration assembly preparation method and optical fiber penetration assembly sealing structure

Abstract

The invention provides a preparation method of an optical fiber penetration assembly, which comprises the following steps: S1, fixing an optical fiber in a casting mold, and putting corresponding metal materials into the casting mold together; and S2, synchronously heating the optical fiber and the metal material, and waiting for solidification of the metal material after the metal material is molten and wraps the optical fiber. The invention further discloses an optical fiber penetration piece sealing structure, the optical fiber penetration piece is manufactured by adopting the manufacturing method, the sealing structure comprises the protruding block located in the middle of the penetration piece and further comprises the pipe bearing and the pressing cap, the pipe bearing and the pressing cap are independent of the two sides of the protruding block respectively, and the other end of the pressing cap is matched with the pipe bearing and used for extruding the protruding block. The protruding block and the pipe bearing are attached and sealed. The thick metal layer is formed outside the optical fiber, and compared with a conventional optical fiber penetration assembly, the sealing effect of the optical fiber penetration assembly is far better than that of the conventional optical fiber penetration assembly; moreover, through a mode of synchronously heating the optical fiber and the metal material, when the metal material is melted to wrap the optical fiber, the optical fiber is not easy to break.

Description

Technical Field

[0001] The invention relates to the technical field of optical fiber penetration parts, and in particular to a method for preparing an optical fiber penetration part and an optical fiber penetration part sealing structure. Background Art

[0002] Under high temperature and high pressure conditions, the application of fiber optic measurement technology has a huge application scenario, but due to the influence of the fiber's own coating and strength, there is a lack of penetration parts that can transition from high temperature and high pressure to normal temperature and pressure and can be sealed.

[0003] Conventional optical fiber penetrations are mainly sealed to optical fibers by means of adhesives, epoxy resins, etc. However, such penetrations cannot be used for a long time under conditions where the temperature is greater than 350°C and the internal and external pressure difference is greater than 10MPa. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for preparing an optical fiber penetration piece and an optical fiber penetration piece sealing structure which has good sealing effect and can be used for a long time under high temperature and high pressure conditions.

[0005] To achieve the above object, the technical solution of the present invention is implemented as follows: a method for preparing an optical fiber penetration component, comprising: S1. Fix the optical fiber in a casting mold, and place the corresponding metal material into the casting mold together; S2. Heat the optical fiber and the metal material simultaneously, wait for the metal material to solidify after it melts and wraps the optical fiber.

[0006] Furthermore, after S2, it also includes: S3. Machining the two ends of the solidified metal material to produce connectors for connecting to corresponding optical fiber instruments.

[0007] Furthermore, the thickness of the solidified metal material is greater than 1 mm.

[0008] Furthermore, in S2, the optical fiber and the metal material in the casting mold are heated by heating the casting mold.

[0009] Furthermore, the casting mold is a graphite mold, and the heating method is eddy current heating.

[0010] Furthermore, when the casting mold is heated, the interior of the casting mold is in a vacuum state.

[0011] Further, in S1 , both ends of the optical fiber extend out of the casting mold.

[0012] Furthermore, the metal material is one of red copper, nickel-based stainless steel, 316 stainless steel or 321 stainless steel.

[0013] Furthermore, the casting mold is divided into a lower mold and an upper mold, a first melting groove is opened in the middle of the lower mold, and a second melting groove is opened in the upper mold at the position corresponding to the first melting groove, the first melting groove and the second melting groove cooperate to form a melting cavity, the internal contour of the melting cavity is consistent with the external contour of the through-piece, and a shrinkage liquid replenishment hole connected to the first melting groove is opened on the upper mold, and the metal material used for melting and replenishing is placed in the shrinkage liquid replenishment hole.

[0014] Furthermore, through grooves for the optical fiber to pass through are provided at both ends of the upper mold, and a clamping component is also provided on the upper mold to fix the optical fiber by pressing.

[0015] Furthermore, the clamping component includes a pressing groove opened at the position of the corresponding through groove of the upper mold, the pressing groove is connected to the through groove, and a pressing block is arranged in the pressing groove; it also includes a screw hole that passes through the pressing groove and the outer side of the upper mold, a screw rod is spirally fitted in the screw hole, and the end of the screw rod is connected to the pressing block.

[0016] Furthermore, the casting mold is heated in a horizontal posture, the upper mold is located above the lower mold, and the shrinkage liquid replenishment hole is located at the top of the melting and casting cavity and is connected to the melting and casting cavity.

[0017] Furthermore, the optical fiber and the metal material are heated synchronously by constant temperature heating; the temperature rise rate of the constant temperature heating includes a rapid heating stage, a transition stage, a melting stage and a step cooling stage, wherein: In the rapid heating stage, the temperature rises rapidly from room temperature to a temperature lower than the melting point of the corresponding metal; In the transition stage, the temperature is maintained at a constant temperature for no less than 5 minutes after the rapid heating stage, and then the temperature is increased in a gradient to a temperature higher than the melting point of the corresponding metal. During the temperature rise process, the temperature needs to be maintained at a constant temperature for no less than 5 minutes for each 100°C increase; In the melting stage, the temperature is maintained at a constant temperature higher than the melting point of the corresponding metal until the metal material is completely melted and wraps the optical fiber; In the step cooling stage, the temperature is lowered in steps until it reaches room temperature.

[0018] An optical fiber penetration sealing structure, the optical fiber penetration is made by the above-mentioned preparation method, the sealing structure comprises a convex block located in the middle of the penetration, arc chamfers are arranged on both sides of the convex block, and the arc chamfers are distributed in a ring shape on both sides of the convex block; It also includes a pipe bearing and a pressure cap, which are independent of the two sides of the protrusion respectively. The pipe bearing is hollow, and one end of the pipe bearing corresponding to the protrusion is provided with a conical surface for contacting and fitting with the corresponding arc chamfer. One end of the through-piece passes through the pressure cap, and one end of the pressure cap corresponding to the protrusion contacts the protrusion. The other end of the pressure cap cooperates with the pipe bearing for squeezing the protrusion so that the protrusion fits and seals with the pipe bearing.

[0019] Furthermore, one end of the corresponding pressure cap of the pipe bearing is provided with an external thread, and the inner side of the pressure cap is provided with an internal thread matching the external thread.

[0020] The beneficial effects of the present invention are embodied in: The present invention forms a thicker metal layer on the outside of the optical fiber by melting the metal material and wrapping the optical fiber. Compared with conventional optical fiber penetrations, the present application directly prepares the penetration on the corresponding optical fiber, and the sealing effect far exceeds that of conventional optical fiber penetrations, and has excellent high temperature and high pressure resistance. Moreover, by simultaneously heating the optical fiber and the metal material, the temperatures of the optical fiber and the metal material are similar, and the optical fiber is not easy to break when the metal material melts and wraps the optical fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In the attached picture: Figure 1 It is an overall view of the casting mold described in the present invention; Figure 2 A half-section view of the casting mold of the present invention; Figure 3 A half-section view of the optical fiber penetration sealing structure of the present invention; Figure 4 It is a structural view of the penetration member described in the present invention.

[0022] Description of reference numerals: 1. Casting mold; 11. Lower mold; 12. Upper mold; 13. Melting cavity; 14. Shrinkage and fluid replenishment hole; 15. Through groove; 16. Pressing groove; 17. Pressing block; 18. Screw hole; 19. Screw; 2. Through piece; 21. Bump; 3. Pipe bearing; 4. Pressing cap. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the invention.

[0024] See also Figures 1 to 4 .

[0025] The present invention discloses a method for preparing an optical fiber penetration component, comprising: S1, fixing the optical fiber in the casting mold 1, and placing the corresponding metal material in the casting mold 1; S2. Heat the optical fiber and the metal material simultaneously, wait for the metal material to solidify after it melts and wraps the optical fiber.

[0026] The preparation method of the optical fiber penetration 2 of the present invention forms a thicker metal layer on the outside of the optical fiber by melting the metal material and wrapping the optical fiber. Compared with the conventional optical fiber penetration 2, the present application directly prepares the penetration 2 on the corresponding optical fiber, and the sealing effect is far superior to the conventional optical fiber penetration 2, and has excellent high temperature and high pressure resistance (as long as the metal is not melted, it can be sealed all the time); Furthermore, the present application heats the optical fiber and the metal material simultaneously to make the temperatures of the optical fiber and the metal material similar, so that the optical fiber is not easy to break. In this way, the highest melting point of the metal material only needs to be slightly lower than the melting point of the optical fiber (the melting point of conventional optical fiber is 1723±5°C). If the molten metal solution is directly poured into the casting mold 1, it is easy to cause a large temperature difference between the optical fiber and the metal material, the optical fiber is easy to break, and the solidified metal material is prone to sand holes, small bubbles, etc.

[0027] When in use, one end of the optical fiber penetration piece 2 is directly placed in a high temperature and high pressure environment, and the other end of the optical fiber penetration piece 2 is located at the normal temperature and differential pressure side, and the outer wall of the optical fiber penetration piece 2 is sealed and matched with the object to be measured.

[0028] In one embodiment, after S2, the method further includes: S3, machining both ends of the solidified metal material to produce connectors connected to corresponding optical fiber instruments.

[0029] In a specific implementation, burrs on the surface of the metal material are removed by machining, and then threads are machined at both ends of the metal material to connect with a fiber optic instrument with an FC / APC fiber optic interface.

[0030] In one embodiment, the thickness of the solidified metal material is greater than 1 mm. In a specific implementation, a metal layer greater than 1 mm facilitates subsequent machining processes.

[0031] In one embodiment, in S2, the optical fiber and the metal material in the casting mold 1 are heated by heating the casting mold 1. With this design, the heating will be more uniform.

[0032] In one embodiment, the casting mold 1 is a graphite mold, and the heating method is eddy current heating. In a specific implementation, the eddy current heating method of the medium frequency furnace is adopted, the mold is completely placed in the heating coil, the direct heating element is the graphite mold surface, and the minimum wall thickness of the mold can be set to be greater than 3mm to achieve uniform temperature of the entire mold.

[0033] In one embodiment, in S1, both ends of the optical fiber extend out of the casting mold 1. With this design, the extended portion of the optical fiber is used to monitor the state of the optical fiber during the processing (for example, to detect whether the optical fiber is broken, to detect the transmission status of the optical fiber). Specifically, the extended portion of the optical fiber is connected to an optical fiber state monitoring device, and the optical fiber state monitoring device is used to monitor the state of the optical fiber during the processing.

[0034] In one embodiment, the metal material is one of red copper, nickel-based stainless steel, 316 stainless steel or 321 stainless steel; wherein, when the operating temperature is ≤350°C and the pressure is ≤20MPa, red copper can be selected as the material; when the operating temperature is between 350-900°C and the pressure is less than 40MPa, nickel-based stainless steel can be selected as the material; when the operating temperature is higher than 900°C, 316 stainless steel or 321 stainless steel can be used.

[0035] In one embodiment, the casting mold 1 is divided into a lower mold 11 and an upper mold 12. A first melting groove is opened in the middle of the lower mold 11, and a second melting groove is opened in the upper mold 12 at the position corresponding to the first melting groove. The first melting groove and the second melting groove cooperate to form a melting cavity 13. The internal contour of the melting cavity 13 is consistent with the external contour of the through-piece 2. A shrinkage liquid replenishment hole 14 connected to the first melting groove is opened on the upper mold 12, and the metal material used for melting and replenishing is placed in the shrinkage liquid replenishment hole 14.

[0036] In a specific implementation, when the corresponding metal materials are placed together in the casting mold 1, the metal materials are not only placed in the melting and casting cavity 13, but also placed in the shrinkage and replenishment holes 14. In this way, the metal materials located in the shrinkage and replenishment holes 14 will flow into the melting and casting cavity 13 after melting, filling the melting and casting cavity 13, so that the melting and casting cavity 13 is filled with metal solution, ensuring that a through-piece 2 of qualified size is obtained.

[0037] In one embodiment, both ends of the upper mold 12 are provided with through grooves 15 for the optical fiber to pass through, and a pressing component is also provided on the upper mold 12; The clamping component includes a pressing groove 16 opened at the position of the corresponding through groove 15 of the upper mold 12, the pressing groove 16 is connected to the through groove 15, and a pressing block 17 is arranged in the pressing groove 16; it also includes a screw hole 18 that passes through the pressing groove 16 and the outer side of the upper mold 12, and a screw rod 19 is spirally fitted in the screw hole 18, and the end of the screw rod 19 is connected to the pressing block 17.

[0038] In a specific implementation, the end of the screw rod 19 is rotatably connected to the pressing block 17. During operation, the optical fiber is passed through the through groove 15, and after the metal material is placed in the casting mold 1, the upper mold 12 and the lower mold 11 are fixed together by bolts, and then the screw rod 19 is rotated to drive the pressing block 17 to move downward, press the optical fiber, and fix the optical fiber; before fixing the optical fiber, the optical fiber in the casting mold 1 can be straightened by pulling the two ends of the optical fiber, and then the optical fiber is fixed to avoid bending of the optical fiber in the mold and affecting the transmission quality.

[0039] In one embodiment, the casting mold 1 is heated in a horizontal posture, the upper mold 12 is located above the lower mold 11, and the shrinkage liquid replenishment hole 14 is located at the top of the melting and casting cavity 13 and is connected to the melting and casting cavity 13. In this design, the molten metal in the shrinkage liquid replenishment hole 14 automatically flows into the melting and casting cavity 13 by gravity, and the horizontal posture makes the molten metal evenly distributed in the melting and casting cavity 13.

[0040] In one embodiment, when the casting mold 1 is heated, the interior of the casting mold 1 is in a vacuum state.

[0041] In a specific implementation, the interior of the casting mold 1 is placed in a vacuum state through a vacuum device (such as a vacuum pump). This can protect the graphite mold from being oxidized by air in a high temperature environment on the one hand, and it is also convenient to discharge the gas in the melting cavity 13 on the other hand, further reducing the possibility of bubbles and sand holes in the body of the penetration piece 2, thereby improving the casting quality of the penetration piece 2.

[0042] In one embodiment, the optical fiber and the metal material are heated synchronously by constant temperature heating; the temperature rise rate of the constant temperature heating includes a rapid heating stage, a transition stage, a melting stage, and a step cooling stage, wherein: In the rapid heating stage, the temperature rises rapidly from room temperature to a temperature lower than the melting point of the corresponding metal; In the transition stage, the temperature is maintained at a constant temperature for no less than 5 minutes after the rapid heating stage, and then the temperature is gradually raised to a temperature higher than the melting point of the corresponding metal. During the temperature increase process, the temperature needs to be maintained at a constant temperature for no less than 5 minutes for each increase of 100°C; In the melting stage, the temperature is maintained at a constant temperature higher than the melting point of the corresponding metal until the metal material is completely melted and wraps the optical fiber; In the step cooling stage, the temperature is lowered in steps until it reaches room temperature.

[0043] In a specific implementation, during the rapid heating stage, the temperature is not allowed to reach the melting point of the metal while rapidly heating up, and then maintained for a period of time to allow the inside of the mold to fully expand due to the heat (equivalent to preheating). The step-by-step temperature rise can allow the metal inside the melting and casting cavity 13 and the metal near the inner wall of the melting and casting cavity 13 to melt almost at the same time, thereby reducing the duration of the coexistence of solid and liquid. After the metal is completely melted and wraps the optical fiber, the temperature is lowered in a gradient to release the internal stress generated during solidification.

[0044] The present invention also discloses a sealing structure of an optical fiber penetration, wherein the optical fiber penetration 2 is made by the above-mentioned preparation method, and the sealing structure comprises a protrusion 21 located in the middle of the penetration 2, and arc chamfers are arranged on both sides of the protrusion 21, and the arc chamfers are distributed in a ring shape on both sides of the protrusion 21; It also includes a pipe support 3 and a pressure cap 4, which are independent of the two sides of the protrusion 21 respectively. The pipe support 3 is hollow, and one end of the pipe support 3 corresponding to the protrusion 21 is provided with a conical surface for contacting and fitting with the corresponding arc chamfer. One end of the penetration piece 2 passes through the pressure cap 4, and one end of the pressure cap 4 corresponding to the protrusion 21 contacts the protrusion 21. The other end of the pressure cap 4 cooperates with the pipe support 3 to squeeze the protrusion 21 so that the protrusion 21 fits and seals with the pipe support 3.

[0045] In specific implementation, the pipe support 3 is welded on the high-temperature and high-pressure pipeline / chamber as a structural reinforcement, and the protrusion 21 in the middle of the penetration piece 2 is squeezed by the pressure cap 4, so that the protrusion 21 and the pipe support 3 are fitted and sealed to achieve sealing; compared with existing sealing forms such as sealants and gaskets, this purely physical structure-based sealing has significantly improved reliability and durability, and under the influence of thermal expansion, the higher the temperature, the better the sealing effect.

[0046] The present invention also discloses a fiber penetration sealing structure, wherein the tube support 3 is provided with an external thread at one end of the corresponding pressure cap 4, and the inner side of the pressure cap 4 is provided with an internal thread matching the external thread. With this design, the pressure cap 4 is connected to the tube support 3 by screw connection, and a pre-pressure can be provided to the protrusion 21 by pre-tightening, thereby improving the sealing performance of the protrusion 21 and the tube support 3.

[0047] It should be noted that if the embodiments of the invention involve directional indications (such as up and down), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0048] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, "multiple" means more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the invention.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an optical fiber penetration, characterized in that: include: S1, fixing the optical fiber in a casting mold (1), and placing the corresponding metal material in the casting mold (1); S2. Heat the optical fiber and the metal material simultaneously, wait for the metal material to solidify after it melts and wraps the optical fiber.

2. The method for preparing an optical fiber penetration member according to claim 1, characterized in that: After S2, it also includes: S3. Machining the two ends of the solidified metal material to produce connectors for connecting to corresponding optical fiber instruments.

3. The method for preparing an optical fiber penetration member according to claim 1 or 2, characterized in that: The thickness of the solidified metal material is greater than 1 mm.

4. The method for preparing an optical fiber penetration member according to claim 1 or 2, characterized in that: In S2, the optical fiber and the metal material in the casting mold (1) are heated by heating the casting mold (1).

5. The method for preparing an optical fiber penetration piece according to claim 4, characterized in that: The casting mold (1) is a graphite mold, and the heating method is eddy current heating.

6. The method for preparing an optical fiber penetration piece according to claim 4, characterized in that: When the casting mold (1) is heated, the interior of the casting mold (1) is in a vacuum state.

7. The method for preparing an optical fiber penetration member according to claim 1 or 2, characterized in that: In S1, both ends of the optical fiber extend out of the casting mold (1).

8. The method for preparing an optical fiber penetration piece according to claim 1 or 2, characterized in that: The metal material is one of red copper, nickel-based stainless steel, 316 stainless steel or 321 stainless steel.

9. The method for preparing an optical fiber penetration member according to claim 1 or 2, characterized in that: The casting mold (1) is divided into a lower mold (11) and an upper mold (12), wherein a first melting groove is provided in the middle of the lower mold (11), and a second melting groove is provided in the upper mold (12) at a position corresponding to the first melting groove, wherein the first melting groove and the second melting groove cooperate to form a melting cavity (13), wherein the inner contour of the melting cavity (13) coincides with the outer contour of the through-piece (2), and a shrinkage liquid replenishment hole (14) connected to the first melting groove is provided on the upper mold (12), and a metal material for melting liquid replenishment is placed in the shrinkage liquid replenishment hole (14).

10. The method for preparing an optical fiber penetration piece according to claim 9, characterized in that: Both ends of the upper mold (12) are provided with through grooves (15) for the optical fiber to pass through, and the upper mold (12) is also provided with a clamping component for fixing the optical fiber by pressing.

11. The method for preparing an optical fiber penetration member according to claim 10, characterized in that: The clamping component includes a pressing groove (16) opened at the position of the corresponding through groove (15) of the upper mold (12), the pressing groove (16) is connected to the through groove (15), and a pressing block (17) is arranged in the pressing groove (16); it also includes a screw hole (18) penetrating the pressing groove (16) and the outer side of the upper mold (12), a screw rod (19) is spirally fitted in the screw hole (18), and the end of the screw rod (19) is connected to the pressing block (17).

12. The method for preparing an optical fiber penetration member according to claim 9, characterized in that: The casting mold (1) is heated in a horizontal posture, the upper mold (12) is located above the lower mold (11), and the shrinkage liquid replenishment hole (14) is located at the top of the melting and casting cavity (13) and is connected to the melting and casting cavity (13).

13. The method for preparing an optical fiber penetration member according to claim 1 or 2, characterized in that: The optical fiber and the metal material are heated synchronously by constant temperature heating; the temperature rise rate of the constant temperature heating includes a rapid heating stage, a transition stage, a melting stage and a step cooling stage, wherein: In the rapid heating stage, the temperature rises rapidly from room temperature to a temperature lower than the melting point of the corresponding metal; In the transition stage, the temperature is maintained at a constant temperature for no less than 5 minutes after the rapid heating stage, and then the temperature is increased in a gradient to a temperature higher than the melting point of the corresponding metal. During the temperature rise process, the temperature needs to be maintained at a constant temperature for no less than 5 minutes for each 100°C increase; In the melting stage, the temperature is maintained at a constant temperature higher than the melting point of the corresponding metal until the metal material is completely melted and wraps the optical fiber; In the step cooling stage, the temperature is lowered in steps until it reaches room temperature.

14. An optical fiber penetration sealing structure, characterized in that: The optical fiber penetration piece (2) is made by the preparation method according to any one of claims 1 to 13, and the sealing structure comprises a protrusion (21) located in the middle of the penetration piece (2), and arc chamfers are arranged on both sides of the protrusion (21), and the arc chamfers are distributed in a ring shape on both sides of the protrusion (21); It also includes a pipe support (3) and a pressure cap (4), wherein the pipe support (3) and the pressure cap (4) are respectively independent of the two sides of the protrusion (21); the pipe support (3) is hollow, and one end of the pipe support (3) corresponding to the protrusion (21) is provided with a conical surface for contacting and fitting with the corresponding arc chamfer; one end of the penetration piece (2) passes through the pressure cap (4), and one end of the pressure cap (4) corresponding to the protrusion (21) contacts the protrusion (21); the other end of the pressure cap (4) cooperates with the pipe support (3) for squeezing the protrusion (21) so that the protrusion (21) and the pipe support (3) fit and seal.

15. The optical fiber penetration sealing structure according to claim 14, characterized in that: One end of the corresponding pressing cap (4) of the pipe bearing (3) is provided with an external thread, and the inner side of the pressing cap (4) is provided with an internal thread matching the external thread.

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