A sensing light unit, a manufacturing method thereof, and a measuring device

Abstract

The application discloses a sensing light unit and a preparation method and a measuring device thereof, and relates to the field of optical information. The sensing light unit comprises a protective tube and a sensing optical fiber in the protective tube, wherein a plurality of wall holes penetrating the wall of the protective tube are arranged on the surface of the protective tube in an axial direction. By arranging the plurality of wall holes penetrating the wall of the protective tube on the surface of the protective tube in the axial direction, and by not filling the gap between the protective tube and the sensing optical fiber with fiber paste, the sensing optical fiber can directly contact the environment to be measured through the wall holes of the protective sleeve, and the sensitive changes of the temperature, humidity, vibration and the like of the external environment can be sensed to the sensing optical fiber through the wall holes, so that the accuracy of the sensing light unit is improved. Meanwhile, the protective sleeve provides protection for the sensing optical fiber, so that the sensing optical fiber is not easily damaged.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical information technology, in particular to a sensing light unit and a preparation method thereof and a measuring device. BACKGROUND

[0002] The sensing optical fiber is a technology that uses the transmission characteristics of light to detect and transmit signals, and is widely used in the monitoring of various physical quantities such as temperature, pressure, displacement, etc.

[0003] The core of the sensing optical fiber is that it can convert the changes of external physical quantities into changes of physical characteristic parameters of light waves, and perceive external signals by measuring the changes of these parameters. Specifically, the sensing optical fiber can modulate and demodulate parameters such as light intensity, wavelength, frequency, phase and polarization state, so as to realize the measurement of various physical quantities.

[0004] However, the existing sensing optical fiber generally has the problem of insufficient sensing precision, which affects the accuracy of measurement. SUMMARY

[0005] The present application provides a sensing light unit to solve the problem of insufficient sensing precision of the existing sensing optical fiber, which affects the accuracy of measurement.

[0006] In a first aspect, the present application provides a sensing light unit, comprising a protective tube and a sensing optical fiber located in the protective tube, wherein the surface of the protective tube is provided with a plurality of wall holes penetrating the wall of the protective tube along the axial direction.

[0007] Since the sensing characteristics of the sensing optical fiber require rapid and accurate perception of parameter signals of changes in the external environment, the sensing optical fiber needs to be fully in contact with the environment to be measured, especially in terms of humidity and temperature measurement. In order to protect the sensing optical fiber, a protective sleeve is usually provided outside the sensing optical fiber. Although this protective sleeve protects the sensing optical fiber, it has an isolating and shielding effect on the changes of sensing parameters, causing the sensing feedback to be insensitive and ineffective, etc.

[0008] In the present application, by providing a plurality of wall holes penetrating the wall of the protective tube along the axial direction on the surface of the protective tube, the sensing optical fiber can directly contact the environment to be measured through the wall holes of the protective sleeve, and the sensitive changes of temperature, humidity, vibration, etc. of the external environment can be sensed to the sensing optical fiber through the wall holes, thereby improving the accuracy of measurement of the sensing light unit. At the same time, since the protective sleeve provides protection for the sensing optical fiber, the sensing optical fiber is not easily damaged.

[0009] In some embodiments, no fiber paste is filled between the protective tube and the sensing optical fiber. In the present application, no fiber paste is filled between the protective tube and the sensing optical fiber, which can also avoid the sensing optical fiber being damaged by the laser focus at the wall hole when the fiber paste is delivered. At the same time, the isolation of the sensing optical fiber and the environment to be measured by the fiber paste is reduced, and the sensitivity of the sensing light unit is improved.

[0010] In some embodiments, the distance between adjacent wall holes is 10-20 mm. Since the main function of the protective tube is to protect the sensing optical fiber, the wall holes arranged on the protective tube will have a certain impact on the strength of the protective tube. In order to reduce the impact on the strength of the protective tube, the distance between the wall holes should not be too close, and at the same time, it should not be too far. If it is too far, it will affect the full contact of the sensing optical fiber and the environment to be measured, and affect the accuracy of the measurement of the sensing optical fiber. The distance between adjacent wall holes in this range can make the sensing optical fiber fully contact with the environment to be measured, while reducing the impact of the wall hole on the structural strength of the protective tube; and / or,

[0011] The shape of the wall hole is circular or elliptical. Since the wall hole on the protective tube is in a through state, there is stress concentration at the edge of the wall hole, and the protective tube is prone to deformation and breakage. The wall hole with sharp corners is more prone to stress concentration at the corner turning point, thereby affecting the strength of the protective tube. Therefore, the circular or elliptical shape can make the stress on the wall hole evenly dispersed, reduce the concentration of stress, and improve the strength of the protective tube.

[0012] In some embodiments, the shape of the wall hole is circular, and the diameter of the circular wall hole is 0.1-0.4 mm. The size of the wall hole will affect the strength of the protective tube and the contact of the sensing optical fiber and the environment to be measured. The wall hole size in this range can make the sensing optical fiber more fully contact with the environment to be measured while reducing the impact on the strength of the protective tube; and / or,

[0013] The shape of the wall hole is elliptical, and the length of the short axis of the elliptical shape is 0.1-0.4 mm, and the length of the long axis of the elliptical shape is 0.2-0.6 mm. The size of the wall hole will affect the strength of the protective tube and the contact of the sensing optical fiber and the environment to be measured. The wall hole size in this range can make the sensing optical fiber more fully contact with the environment to be measured while reducing the impact on the strength of the protective tube. It should be noted that further, when the shape of the wall hole is elliptical, the long axis of the wall hole is in the radial direction of the protective tube, and the short axis of the wall hole is in the circumferential direction of the protective tube, which can further reduce the impact of the wall hole on the strength of the protective tube.

[0014] In some embodiments, the sum of the areas of the plurality of wall holes is S1, and the lateral area of the protective tube is S2, wherein 1%≤S1 / S2≤10%. Due to the wall holes provided on the protective tube, the wall holes affect the strength of the protective tube, and the strength of the protective tube affects the service life of the optical fiber. In order to simultaneously satisfy the sufficient contact between the sensing optical fiber and the environment to be measured and retain the protection strength of the protective tube, the area of the wall holes is within the range, which can reduce the influence of the wall holes on the strength of the protective tube and increase the contact between the sensing optical fiber and the environment to be measured.

[0015] In some embodiments, the outer diameter of the protective tube is 1.8-3.5 mm. The outer diameter of the protective tube has a greater influence on the stress of the protective tube. When the outer diameter of the protective tube is within the range, the protective tube is less likely to break and deform after the wall holes are provided, which is conducive to improving the strength of the protective tube; and / or,

[0016] The thickness of the protective tube is 0.10-0.25 mm. The thicker the protective tube is, the greater the strength is, and the smaller the influence of the wall holes on the strength of the protective tube is. However, the cost and weight are also greater. When the thickness of the protective tube is within the range, the influence of the wall holes on the strength of the protective tube can be reduced; and / or,

[0017] The material of the protective tube includes stainless steel. The stainless steel has the characteristics of good protection strength, salt resistance, and corrosion resistance, is more suitable for variable measurement environments, and provides protection for the optical fiber. At the same time, due to the good strength, the influence of the wall holes on the strength of the protective tube can be reduced.

[0018] It should be noted that in some embodiments of the present application, the wall holes on the protective tube can be uniformly or non-uniformly arranged in a single column along the axial direction of the protective tube. In other embodiments of the present application, the wall holes on the protective tube can be uniformly or non-uniformly arranged in multiple columns along the axial direction of the protective tube. The selection can be made according to the actual use requirements. The wall holes on the protective tube can be uniformly arranged in a single column along the axial direction of the protective tube, which is easier to form, for example, a steel plate is cut by a cutter, and then welded to achieve. The wall holes on the protective tube can be arranged in multiple non-uniform columns along the axial direction of the protective tube, and the stress is less likely to concentrate in the same direction, which can reduce the influence on the strength of the protective tube. The multiple wall holes on the protective tube can be formed by laser drilling, but this method has the risk of damaging the sensing optical fiber.

[0019] In a second aspect, the present application provides a preparation method of a sensing light unit, which is used to prepare the sensing light unit of the first aspect of the present application, and includes the following steps:

[0020] A plurality of half wall hole shapes are formed at corresponding positions on both sides of the plate material of the protective tube;

[0021] The sensing optical fiber is wrapped in the protective tube enclosed by the protective tube plate to obtain the sensing light unit.

[0022] The plurality of half-wall hole shapes enclose wall holes of the protection tube.

[0023] By forming the plurality of half-wall hole shapes on the two sides of the protection tube plate at corresponding positions respectively, the protection tube plate encloses the protection tube, and the plurality of half-wall hole shapes enclose wall holes of the protection tube. The forming of the wall holes can be completed at the stage of the steel plate, and the protection tube does not need to be formed again after the sensing optical fiber is wrapped, so that the process can be reduced, and the damage to the sensing optical fiber can be reduced.

[0024] In some embodiments, the method of forming the plurality of half-wall hole shapes on the two sides of the protection tube plate at corresponding positions respectively includes cutting the plurality of half-wall hole shapes on the two sides of the steel plate in a corresponding manner by using a cutter with a special-shaped concave-convex opening. By using the special-shaped concave-convex opening of the cutter, the corresponding shape is cut on the steel plate during cutting, and the wall hole is formed during welding. The edge burrs of the hole eyes in the conventional punching mode such as mechanical stamping are avoided, and the problem of broken tube during production is avoided. The special design on the cutter die does not add the process, and the hole diameter is uniform and controllable.

[0025] In some embodiments, the protection tube plate is enclosed to form the protection tube by welding first and then stretching. The moving speed of the protection tube during welding is V1, and the moving speed of the protection tube during stretching is V2, wherein:

[0026] 1.1≤V2 / V1≤1.3, the moving speed of the protection tube during stretching is 1.1 to 1.3 times the moving speed of the protection tube during welding, which can reduce the influence of stress release on the protection tube due to the existence of the wall hole during the stretching stage, eliminate potential hazards, and reduce the influence of the wall hole on the strength of the protection tube; and / or,

[0027] 8m / min≤V1≤15m / min, the moving speed of the protection tube during welding is in this range, which can improve the welding effect and improve the strength of the protection tube; and / or,

[0028] 8.8m / min≤V2≤19.5m / min, the moving speed of the protection tube during stretching is in this range, which can make the stress release of the protection tube more sufficient and improve the strength of the protection tube.

[0029] In a third aspect, the present application provides a measuring device, which comprises the sensing light unit of the first aspect of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] Figure 1 Schematic diagram of the structure of a light sensing unit according to an embodiment of the present application.

[0032] Figure 2 This is a structural diagram of a light sensing unit according to another embodiment of the present application.

[0033] Figure 3 This is a structural diagram of a light sensing unit according to another embodiment of the present application.

[0034] Figure 4 This is a structural diagram of a light sensing unit according to another embodiment of the present application.

[0035] Figure 5 This is a flow chart of an embodiment of a method for manufacturing a light sensing unit of the present application.

[0036] Figure 6 A schematic diagram of a cutting tool according to an embodiment of a method for manufacturing a light sensing unit of the present application.

[0037] Figure 7 A schematic diagram of steel plate cutting according to an embodiment of a method for manufacturing a light sensing unit of the present application.

[0038] Figure 8 A schematic diagram of steel plate cutting according to another embodiment of the method for preparing the light sensing unit of the present application.

[0039] Description of Figure Numbers:

[0040] 100 sensing light unit; 1 protective layer; 11 wall hole; 2 sensing optical fiber. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of this application without making any creative efforts shall fall within the scope of protection of this application.

[0042] Optical fiber sensing is a technology that uses the transmission characteristics of light to detect and transmit signals. It is widely used in monitoring various physical quantities such as temperature, pressure, and displacement.

[0043] The core of the sensing optical fiber is that it can convert the change of the physical quantity of the outside world into the change of the physical characteristic parameter of the light wave, and perceive the outside signal by measuring the change of these parameters. Specifically, the sensing optical fiber can modulate and demodulate parameters such as light intensity, wavelength, frequency, phase and polarization state, so as to realize the measurement of various physical quantities.

[0044] However, the existing sensing optical fiber generally has the problem of insufficient sensing precision, which affects the accuracy of measurement.

[0045] Therefore, the present application provides a sensing light unit to solve the problem of insufficient sensing precision of the existing sensing optical fiber, which affects the accuracy of measurement.

[0046] In a first aspect, as shown in Figure 1 and Figure 2 The present application provides a sensing light unit 100, which comprises a protective tube and a sensing optical fiber 2 located in the protective tube, wherein the surface of the protective tube is provided with a plurality of wall holes 11 penetrating the wall of the protective tube in an axial direction.

[0047] Because the sensing characteristics of the sensing optical fiber 2 require quick and accurate sensing of parameter signals in response to changes in the external environment, the sensing optical fiber 2 needs to be in full contact with the environment to be measured, especially in terms of humidity and temperature measurement. In order to protect the sensing optical fiber 2, a protective sleeve is usually provided outside the sensing optical fiber 2. Although this protective sleeve protects the sensing optical fiber 2, it has an isolating and shielding effect on the change of the sensing parameter, causing the sensing feedback to be insensitive and ineffective.

[0048] In the present application, by providing a plurality of wall holes 11 penetrating the wall of the protective tube in an axial direction on the surface of the protective tube, the sensing optical fiber 2 can directly contact the environment to be measured through the wall holes 11 of the protective sleeve. The sensing optical fiber 2 can sense the sensitive changes of temperature, humidity, vibration and other changes of the external environment, thereby improving the accuracy of measurement of the sensing light unit 100. At the same time, the protective sleeve provides protection for the sensing optical fiber 2, so that the sensing optical fiber 2 is not easily damaged.

[0049] It should be noted that, as shown in Figures 1 to 4As shown in some embodiments of the present application, the shape of the wall hole 11 is not limited, for example, it can be square, circular, triangular, polygonal, etc. In some embodiments of the present application, the arrangement of the wall hole 11 is also not limited, for example, the wall hole 11 of different shapes can be arranged randomly, or the wall hole 11 of the same shape can be arranged uniformly, which can be selected according to actual needs. In some embodiments of the present application, the wall hole 11 can be arranged in one row along the axial direction, or can be arranged in multiple rows, and when arranged in multiple rows, it can be arranged at equal intervals or at unequal intervals.

[0050] In combination with the first aspect, in some embodiments provided by the present application, no fiber paste is filled between the protective tube and the sensing optical fiber. In the present application, no fiber paste is filled between the protective tube 1 and the sensing optical fiber 2, which can also avoid that the sensing optical fiber 2 is damaged by laser focus at the wall hole 11 when the fiber paste is delivered. At the same time, the isolation of the sensing optical fiber 2 and the environment to be measured by the fiber paste is reduced, and the sensitivity of the sensing light unit 100 is improved.

[0051] In combination with the first aspect, in some embodiments provided by the present application, the distance between adjacent wall holes 11 is 10-20 mm. Since the main function of the protective tube is to protect the sensing optical fiber 2, the wall hole 11 arranged on the protective tube will affect the strength of the protective tube to a certain extent. In order to reduce the influence on the strength of the protective tube, the distance between the wall holes 11 should not be too close, and at the same time, it should not be too far, because too far will affect the full contact of the sensing optical fiber 2 and the environment to be measured, and affect the accuracy of the measurement of the sensing optical fiber 2. The distance between adjacent wall holes 11 in this range can make the sensing optical fiber 2 fully contact with the environment to be measured, and at the same time reduce the influence of the wall hole 11 on the structural strength of the protective tube. The distance between adjacent wall holes 11 includes but is not limited to 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm or 20 mm.

[0052] In combination with the first aspect, as Figure 3 and 4 shown in some embodiments provided by the present application, the shape of the wall hole 11 is circular or elliptical. Since the wall hole 11 on the protective tube is in a penetrating state, there is stress concentration at the edge of the wall hole 11, and the protective tube is prone to deformation and breakage. The wall hole 11 with sharp corners is more prone to stress concentration at the corner turning part, thereby affecting the strength of the protective tube. Therefore, the circular or elliptical shape can make the stress on the wall hole 11 uniformly dispersed, reduce the concentration of stress, and improve the strength of the protective tube.

[0053] In some embodiments of the first aspect, the wall hole 11 is circular, and the diameter of the circular wall hole 11 is 0.1-0.4 mm. The size of the wall hole 11 affects the strength of the protective tube and the contact of the sensing optical fiber 2 with the environment to be measured. When the size of the wall hole 11 is within the range, the contact of the sensing optical fiber 2 with the environment to be measured is more sufficient while the influence of the wall hole 11 on the strength of the protective tube is reduced. The diameter of the circular wall hole 11 includes but is not limited to 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, or 0.4 mm.

[0054] In some embodiments of the first aspect, the wall hole 11 is elliptical, and the length of the short axis of the elliptical wall hole 11 is 0.1-0.4 mm, and the length of the long axis of the elliptical wall hole 11 is 0.2-0.6 mm. The size of the wall hole 11 affects the strength of the protective tube and the contact of the sensing optical fiber 2 with the environment to be measured. When the size of the wall hole 11 is within the range, the contact of the sensing optical fiber 2 with the environment to be measured is more sufficient while the influence of the wall hole 11 on the strength of the protective tube is reduced. It should be noted that when the shape of the wall hole 11 is elliptical, the long axis of the wall hole 11 is in the radial direction of the protective tube, and the short axis of the wall hole 11 is in the circumferential direction of the protective tube, the influence of the wall hole 11 on the strength of the protective tube can be further reduced. The length of the short axis of the elliptical wall hole 11 includes but is not limited to 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, or 0.4 mm. The length of the long axis of the elliptical wall hole 11 includes but is not limited to 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, or 0.6 mm.

[0055] In some embodiments of the first aspect, the sum of the areas of the plurality of wall holes 11 is S1, and the lateral area of the protective tube is S2, and 1%≤S1 / S2≤10%. Since the wall hole 11 is provided on the protective tube, the presence of the wall hole 11 affects the strength of the protective tube, which affects the service life of the optical fiber. In order to simultaneously satisfy the sufficient contact of the sensing optical fiber 2 with the environment to be measured and retain the protective strength of the protective tube, the area of the wall hole 11 is within the range, which can reduce the influence of the wall hole 11 on the strength of the protective tube and increase the contact of the sensing optical fiber 2 with the environment to be measured. The value of S1 / S2 includes but is not limited to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%.

[0056] In some embodiments of the first aspect, the outer diameter of the protection tube is 1.8-3.5 mm. The outer diameter of the protection tube has a greater impact on the stress of the protection tube. When the outer diameter of the protection tube is within this range, the protection tube is less likely to break and deform after the wall hole 11 is opened, which is conducive to improving the strength of the protection tube. The outer diameter of the protection tube includes, but is not limited to, 1.8 mm, 2.0 mm, 2.3 mm, 2.5 mm, 2.7 mm, 3.0 mm, 3.2 mm, or 3.5 mm.

[0057] In some embodiments of the first aspect, the thickness of the protection tube is 0.10-0.25 mm. The thicker the protection tube, the greater the strength, and the smaller the impact of the wall hole 11 on the strength of the protection tube. However, the cost and weight are also greater. When the thickness of the protection tube is within this range, the impact of the wall hole 11 on the strength of the protection tube can be reduced. The thickness of the protection tube includes, but is not limited to, 0.1 mm, 0.12 mm, 0.15 mm, 0.17 mm, 0.20 mm, 0.22 mm, or 0.25 mm.

[0058] In some embodiments of the first aspect, the material of the protection tube includes stainless steel. Stainless steel has the characteristics of good protection strength, salt resistance, and corrosion resistance, and is more suitable for changing measurement environments. It provides protection for the optical fiber. At the same time, due to its good strength, the impact of the wall hole 11 on the strength of the protection tube can be reduced. The stainless steel can be selected from 304 or 316 type stainless steel.

[0059] It should be noted that in some embodiments of the present application, the wall holes 11 on the protection tube can be uniformly or non-uniformly arranged in a single column along the axial direction of the protection tube. In some other embodiments of the present application, the wall holes 11 on the protection tube can be uniformly or non-uniformly arranged in multiple columns along the axial direction of the protection tube. The selection can be made according to the actual use requirements. Among them, the wall holes 11 on the protection tube can be uniformly arranged in a single column along the axial direction of the protection tube, which is easier to form, for example, a steel plate is cut by a cutter, and then welded to achieve. The wall holes 11 on the protection tube can be arranged in multiple non-uniform columns along the axial direction of the protection tube. The stress is less likely to concentrate in the same direction, which can reduce the impact on the strength of the protection tube. Multiple wall holes 11 can be formed on the protection tube by laser drilling. However, this method has the risk of damaging the sensing optical fiber 2.

[0060] In some embodiments of the first aspect, the sensing optical unit 100 further includes a sensing optical fiber 2. Figure 5 As shown in FIG. 10, the present application provides a preparation method of a sensing optical unit 100 for preparing the sensing optical unit 100 of the first aspect of the present application, including the following steps:

[0061] S10, forming multiple half-wall hole shapes on the corresponding positions of the two sides of the plate material of the protection tube;

[0062] S20, wrapping the sensing optical fiber in the protection tube formed by the plate material of the protection tube, to obtain a sensing optical unit 100;

[0063] The plurality of half-wall holes form a wall hole of the protection tube.

[0064] By forming a plurality of half-wall holes 11 on both sides of the plate material of the protection tube, the protection tube formed by the plate material of the protection tube, and the plurality of half-wall holes 11 form a wall hole 11 of the protection tube, the forming of the wall hole 11 can be completed at the steel plate stage, and after wrapping the sensing optical fiber 2, the protection tube does not need to be formed again, which can reduce the process and reduce the damage to the sensing optical fiber 2.

[0065] In some embodiments provided by the present application, the method of forming a plurality of half-wall holes 11 on both sides of the plate material of the protection tube includes cutting a plurality of half-wall holes 11 on both sides of the steel plate in a corresponding way by using a cutter with a special-shaped concave-convex hole. Figures 6 to 8 The special-shaped concave-convex hole of the cutter can cut a corresponding shape when the steel plate is cut, and the wall hole 11 is formed when welding, which avoids the problem of many burrs on the edges of the hole formed by the conventional punching method such as mechanical stamping, and the problem of broken tube during production. The special design on the cutter die does not add the process, and the hole diameter is uniform and controllable. The position, size and number of the concave-convex hole of the cutter can control the position and size of the wall hole 11 in the protection tube.

[0066] In some embodiments provided by the present application, the plate material of the protection tube is formed into a protection tube by welding first and then stretching. The moving speed of the protection tube during welding is V1, and the moving speed of the protection tube during stretching is V2, wherein 1.1≤V2 / V1≤1.3. The moving speed of the protection tube during stretching is 1.1 to 1.3 times the moving speed of the protection tube during welding, which can reduce the influence of stress release on the protection tube due to the existence of the wall hole 11 during the stretching stage, eliminate potential hazards, and reduce the influence of the wall hole 11 on the strength of the protection tube. The value of V2 / V1 includes but is not limited to 1.1, 1.15, 1.20, 1.25 or 1.3.

[0067] With reference to the second aspect, in some embodiments provided in the present application, the plate material of the protection pipe is enclosed to form the protection pipe in the way of welding first and then stretching. The moving speed of the protection pipe during welding is V1, and the moving speed of the protection pipe during stretching is V2, wherein 8 m / min≤V1≤15 m / min. Since the wall hole is arranged on the protection pipe, the wall hole will have a certain influence on the strength of the protection pipe, and therefore it is necessary to control the moving speed of the protection pipe during welding and the moving speed of the welded pipe during stretching. The moving speed of the protection pipe during welding is within the range, so that stable welding quality and stable pipe forming effect can be obtained, the production of the welded pipe can be continuously and smoothly carried out, the deviation of the stainless steel strip caused by the speed during welding can be reduced, and the situation of pipe breakage at the wall hole of the welded pipe can be avoided. The moving speed V1 of the protection pipe during welding includes but is not limited to 8 m / min, 9 m / min, 10 m / min, 11 m / min, 12 m / min, 13 m / min, 14 m / min or 15 m / min.

[0068] With reference to the second aspect, in some embodiments provided in the present application, the plate material of the protection pipe is enclosed to form the protection pipe in the way of welding first and then stretching. The moving speed of the protection pipe during welding is V1, and the moving speed of the protection pipe during stretching is V2, wherein 8.8 m / min≤V2≤19.5 m / min. The moving speed of the protection pipe during stretching is within the range, so that the outer diameter change effect can be obtained, the strength of the protection pipe is improved, and the probability of the situations such as breakage and hole deformation of the welded pipe at the wall hole during stretching is reduced. The moving speed V2 of the protection pipe during stretching includes but is not limited to 8.8 m / min, 9.0 m / min, 9.5 m / min, 10.0 m / min, 11.0 m / min, 12.0 m / min, 13.0 m / min, 14.0 m / min, 15.0 m / min, 16.0 m / min, 17.0 m / min, 18.0 m / min, 19.0 m / min or 19.5 m / min.

[0069] In a third aspect, the present application provides a measuring device comprising the sensing light unit 100 of the first aspect of the present application. The measuring device has all the technical solutions of the sensing light unit 100, and thus also has all the beneficial effects of the sensing light unit 100, which will not be repeated here. The measuring device includes but is not limited to a temperature measuring device or a humidity measuring device.

[0070] In summary, by arranging a plurality of wall holes penetrating the wall of the protection tube in the surface of the protection tube in an axial direction, and not filling the protection tube with fiber paste between the protection tube and the sensing optical fiber, the sensing optical fiber can directly contact the environment to be measured through the wall holes of the protection sleeve, and the sensitive changes of the external environment such as temperature, humidity and vibration can be sensed to the sensing optical fiber through the wall holes, thereby improving the measurement accuracy of the sensing optical unit. At the same time, the protection sleeve provides protection for the sensing optical fiber, so that the sensing optical fiber is not easily damaged.

[0071] In the description of the present specification, the description of the terms "one embodiment / way", "some embodiments / ways", "example", "specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment / way or example are included in at least one embodiment / way or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment / way or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments / ways or examples. In addition, the person skilled in the art can combine and combine the different embodiments / ways or examples described in the present specification and the features of the different embodiments / ways or examples without contradiction.

[0072] It should be noted that in the present application, the relationship terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element. In the present application, the meaning of "a plurality of" is at least two, for example two, three, etc., unless otherwise explicitly specified.

[0073] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications of these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A light sensing unit, characterized in that: The optical sensing unit comprises a protective tube and a sensing optical fiber located in the protective tube, wherein a plurality of wall holes penetrating the wall of the protective tube are provided on the surface of the protective tube at intervals along the axial direction. The optical sensing unit is prepared by the following steps: A plurality of half-wall holes are formed at corresponding positions on both sides of the plate of the protection tube; Wrapping the sensing optical fiber in a protective tube formed by the protective tube plate to obtain a sensing optical unit; wherein the shapes of the multiple half-wall holes enclose the wall hole of the protection tube; The plates of the protection tube are welded first and then stretched to form the protection tube: The moving speed of the protective tube during welding is V1, and the moving speed of the protective tube during stretching is V2, wherein 1.1≤V2 / V1≤1.3; 8.8m / min≤V2≤19.5m / min; 8m / min≤V1≤15m / min.

2. The light sensing unit according to claim 1, wherein No fiber paste is filled between the protection tube and the sensing optical fiber.

3. The light sensing unit according to claim 1, wherein: The spacing between adjacent wall holes is 10-20 mm; and / or, The shape of the wall hole is circular or elliptical.

4. The light sensing unit according to claim 3, wherein: The shape of the wall hole is circular, wherein the diameter of the circular wall hole is 0.1-0.4 mm; and / or, The shape of the wall hole is elliptical, wherein the length of the short axis of the ellipse is 0.1-0.4 mm, and the length of the long axis of the ellipse is 0.2-0.6 mm.

5. The light sensing unit according to claim 1, wherein: The sum of the areas of the plurality of wall holes is S1, and the side area of ​​the protection tube is S2, wherein 1%≤S1 / S2≤10%.

6. The light sensing unit according to claim 1, wherein: The outer diameter of the protective tube is 1.8 to 3.5 mm; and / or, The thickness of the protective tube is 0.10-0.25 mm; and / or, The material of the protection tube includes stainless steel.

7. A method for preparing a light sensing unit according to any one of claims 1 to 6, characterized in that: The following steps are involved: A plurality of half-wall holes are formed at corresponding positions on both sides of the plate of the protection tube; Wrapping the sensing optical fiber in a protective tube formed by the protective tube plate to obtain a sensing optical unit; The shapes of the multiple half-wall holes are enclosed to form the wall hole of the protection tube.

8. The method for preparing a light sensing unit according to claim 7, wherein: In the method of forming multiple half-wall hole shapes at corresponding positions on both sides of the plate of the protective tube, the method of forming multiple half-wall hole shapes includes using a cutter with corresponding shaped concave and convex openings to cut multiple half-wall hole shapes on both sides of the steel plate.

9. The method for preparing a light sensing unit according to claim 7, wherein: The plates of the protection tube are welded first and then stretched to form the protection tube: The moving speed of the protective tube during welding is V1, and the moving speed of the protective tube during stretching is V2, wherein 1.1≤V2 / V1≤1.3; and / or, The moving speed of the protective tube during stretching is V2, 8.8m / min≤V2≤19.5m / min; and / or, The moving speed of the protective tube during welding is V1, 8m / min≤V1≤15m / min.

10. A measuring device, characterized in that: The device comprises a light sensing unit according to any one of claims 1 to 6.

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