CN104931190A - Non-glue mechanical sealing structure of fiber grating osmometer - Google Patents

Abstract

The present invention aims at overcoming the problems in the prior art that fiber grating piezometers use waterproof glue to seal with poor stability, poor sealing effect and affecting the precision of piezometers, and provides a glue-free mechanical seal for fiber grating piezometers The structure uses nylon tubes, pressure-resistant quick-twist joints, and heat-shrinkable tubes instead of traditional waterproof glue to seal the fiber grating piezometer, and supports it through metal support tubes. Because of its special material, the nylon tube can withstand the pressure of 10Mpa without serious deformation, so it is used as the protective sleeve of the optical fiber; the pressure-resistant quick-twist connector can be squeezed through the nylon tube to achieve the sealing effect; the heat-shrinkable tube is used It is firm and reliable for the butt joint between optical cable and nylon tube; hydraulic pliers are used to squeeze the metal support tube to achieve the sealing effect. The invention can solve the shortcomings of poor long-term stability and small pressure-resistant range of the existing sealant sealing mode through the mechanical sealing structure.

Description

A fiber grating osmometer mechanical seal structure without glue

technical field

The invention belongs to the field of optical fiber sensing, and in particular relates to a glue-free pure mechanical sealing structure of an optical fiber grating piezometer.

Background technique

Piezometers are mainly used for long-term measurement of pressure in fluids, pores, dams, subways, bridges, etc. Nowadays, most of them use traditional electric piezometers. Traditional electric piezometers have disadvantages such as low measurement accuracy, poor waterproof performance, short life, and poor anti-electromagnetic interference ability; fiber grating piezometers can overcome traditional electric piezometers. The shortcomings of the piezometer have many advantages such as high measurement accuracy, large measurement range, high waterproof performance, and anti-electromagnetic interference. However, the optical grating osmometers on the market use waterproof glue to increase water resistance. Because the waterproof glue is measured for a long time, the stability will gradually decrease due to the glue itself, and the pressure resistance range of the waterproof glue is small. Therefore, there is an urgent need for a reliable and stable fiber grating piezometer sealing structure.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the problem that the optical fiber grating osmometer uses waterproof glue to seal the poor stability, poor sealing effect and affect the precision of the osmometer in the prior art, and provides a fiber grating osmometer Meter without glue mechanical seal structure.

In order to solve the problems of the technologies described above, the present invention is achieved by adopting the following technical solutions:

An adhesive-free mechanical seal structure of a fiber grating piezometer, including a fiber grating piezometer composed of a fiber grating, characterized in that a pressure-resistant quick-twist unidirectional joint is connected to the fiber grating piezometer through threads, and the pressure resistance is fast. The other end of the one-way connector is a threaded nut structure, and one end of the first section of nylon tube is sealed and installed on the other end of the pressure-resistant one-way connector through the threaded nut structure of the pressure-resistant quick-twist one-way connector, and the fiber grating is infiltrated The optical fiber protruding from the gauge passes through the pressure-resistant quick-twist one-way connector, and the optical fiber fusion splicing process for connecting two sections of optical fibers is placed in the first section of nylon tube, and the other end of the first section of nylon tube and a threaded nut at both ends One end of the structural pressure-resistant quick-twist two-way joint is sealed and connected, and the other end of the pressure-resistant quick-twist two-way joint is sealed and connected to the second section of nylon tube. The optical fiber continues to pass through the second section of nylon tube, and a metal support tube is set on the optical cable , using the method of metal crimping to squeeze and crimp the second section of nylon tube and the optical cable together, and mechanically deform the metal support tube and the corresponding second section of nylon tube outside it to form a deformed part, which can be squeezed and sealed Effect;

Further technical solutions include:

The first section of nylon tube is filled with waterproof glue;

The deformation is covered with a heat shrinkable tube for external protection.

Compared with prior art, the beneficial effects of the present invention are:

Most fiber grating osmometers on the market still rely on the bonding of waterproof glue to ensure the sealing performance at the outlet of the pigtail fiber. Due to the characteristics of the waterproof glue, this method has a small range of pressure resistance and poor long-term stability. The present invention The above-mentioned fiber grating piezometer without glue and pure mechanical seal structure solves the pressure-resistant sealing problem of the fiber grating piezometer in an underwater 10Mpa environment completely through mechanical extrusion, and solves the protection of the welding point at one time Sealing problem.

Description of drawings

Below in conjunction with accompanying drawing, the present invention will be further described:

Fig. 1 is a structural schematic diagram of a glueless pure mechanical seal structure of a fiber grating piezometer according to the present invention.

In the figure: 1. Pressure-resistant quick-twist one-way joint, 2. Pressure-resistant quick-twist two-way joint, 3. The second section of nylon tube, 4. Optical fiber grating piezometer, 5. Metal support tube, 6. Deformation, 7 . Heat-shrinkable tube, 8. Optical cable, 9. Optical fiber fusion joint, 10. The first section of nylon tube, 11. Optical fiber.

Detailed ways

The present invention is described in detail below in conjunction with accompanying drawing:

A fiber grating piezometer adhesive-free mechanical seal structure, including a fiber grating piezometer 4 composed of a fiber grating, characterized in that a pressure-resistant quick-twist one-way joint 1 and the fiber grating piezometer 4 are butted through threads, The other end of the pressure-resistant quick-twist one-way joint 1 is a threaded nut structure, and one end of the first segment of nylon tube 10 is sealed and installed on the pressure-resistant quick-twist one-way joint 1 through the threaded nut structure of the pressure-resistant quick-tighten one-way joint 1 At the other end, the optical fiber 11 protruding from the fiber grating piezometer 4 passes through the pressure-resistant quick-twist one-way joint, and the optical fiber fusion splice 9 is placed in the first section of nylon tube 10, and the other end of the first section of nylon tube 10 is connected to a One end of the pressure-resistant quick-twist two-way connector 2 with threaded nut structure at both ends is sealed and connected, and the other end of the pressure-resistant quick-twist two-way joint 2 is sealed and connected to the second section of nylon tube 3, and the optical fiber 11 continues to pass through the second section of nylon tube 3. However, the optical cable 8 is covered with a metal support tube 5, and the second section of nylon tube 3 and the optical cable 8 are squeezed and crimped together by metal crimping, and the metal support tube 5 and the corresponding second section of nylon tube are connected together. The tube 3 is mechanically deformed to form a deformed part 6. The deformed part 6 achieves the effect of extrusion and sealing. The first section of nylon tube 10 is filled with waterproof glue, and the outer part of the deformed part 6 is covered with a heat shrinkable tube 7 for external protection.

The operation process of sealing and protecting the optical fiber 11 in the fiber Bragg grating piezometer 4 by using the adhesive-free mechanical seal structure of the fiber Bragg grating piezometer according to the present invention is as follows:

In the first step, screw one end of the pressure-resistant quick-twist one-way connector 1 to the fiber outlet end of the fiber grating piezometer 4;

In the second step, the first section of nylon tube 10 is softened at 80 degrees, and then put on the pressure-resistant quick-twist one-way joint 1;

The third step is to lock the sealing nut of the pressure-resistant quick-twist one-way joint 1;

The fourth step is to cut off a section of the optical fiber in the first section of nylon tube 10 to prepare for fusion splicing;

The fifth step, the welding is successful, ready for protection;

The sixth step is to add a resin plate to the optical fiber fusion joint 9 and then coat the board with ultraviolet glue to strengthen and fix the optical fiber fusion joint 9. Filled with 704 waterproof glue;

The seventh step is to connect the first section of nylon tube 10 and the second section of nylon tube 3 through the pressure-resistant quick-twist two-way joint 2 and lock them. Protect two points that are prone to leakage: the fiber outlet of the fiber grating piezometer 4 and the fiber fusion joint 9 where the fiber is extended.

In the eighth step, after the 4 roots of the fiber grating osmometer with high pressure are protected through the above steps, as shown in Figure 1, the metal support tube 5 is first set on the second section of nylon tube 3, and the optical fiber penetrates into the second section The nylon tube 3 uses hydraulic pliers to deform the metal support tube 5 to form a deformed part 6 to achieve the effect of extrusion and sealing, and finally uses a heat shrinkable tube 7 for external protection.

Claims (3)

1. a fiber bragg grating osmometer glue-free mechanical hermetically-sealed construction, comprise a fiber bragg grating osmometer be made up of fiber grating (4), it is characterized in that a withstand voltage fast one-way joint (1) of twisting is docked by screw thread with fiber bragg grating osmometer (4), the withstand voltage fast other end of twisting one-way joint (1) is screw nut structure, by withstand voltage fast screw nut structure of twisting one-way joint (1), one end of first paragraph nylon tube (10) sealing is arranged on the withstand voltage fast other end of twisting one-way joint (1), the optical fiber (11) that fiber bragg grating osmometer (4) stretches out passes from withstand voltage fast twisting one-way joint (1), fused fiber splice place (9) is placed in first paragraph nylon tube (10), the other end of first paragraph nylon tube (10) and two ends are that withstand voltage fast one end of twisting bidirectional joint (2) of screw nut structure is tightly connected, the withstand voltage fast other end of twisting bidirectional joint (2) is tightly connected second segment nylon tube (3), optical fiber (11) continues to pass from second segment nylon tube (3), metallic support pipe (5) is had at the upper cover of optical cable (8), the method of metal crimp is adopted second segment nylon tube (3) and optical cable (8) to be crimped together, metallic support pipe (5) and its outer corresponding second segment nylon tube (3) are carried out mechanically deform thus form distortion place (6), distortion place (6) reaches crush seal effect.

2., according to the said a kind of fiber bragg grating osmometer glue-free mechanical hermetically-sealed construction of claim 1, it is characterized in that being full of marine glue in first paragraph nylon tube (10).

3., according to claim 1 or 2 said fiber bragg grating osmometer glue-free mechanical hermetically-sealed construction, it is characterized in that distortion place (6) outer cover has heat-shrink tube (7) to do outer protection.