Sensing light unit, preparation method thereof and measuring device

Abstract

The invention discloses a sensing optical unit, a preparation method thereof and a measuring device, and relates to the field of optical information. The sensing optical unit comprises a protection tube and a sensing optical fiber located in the protection tube, and a plurality of wall holes penetrating through the tube wall of the protection tube are formed in the surface of the protection tube at intervals in the axial direction. A plurality of wall holes penetrating through the pipe wall of the protection pipe are formed in the surface of the protection pipe at intervals in the axial direction, and fiber paste is not filled between the protection pipe and the sensing optical fiber, so that the sensing optical fiber can penetrate through the wall holes of the protection sleeve to be in direct contact with the environment to be detected, and the temperature of external environment change can be detected through the wall holes. Sensitive changes such as humidity, vibration and the like are sensed to the sensing optical fiber, the measurement accuracy of the sensing optical unit is improved, and meanwhile, the sensing optical fiber is protected by the protective sleeve, so that the sensing optical fiber is not easy to damage.

Description

Technical Field

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

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

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

[0004] However, existing optical fibers for sensing generally have the problem of insufficient sensing precision, which affects the accuracy of measurement. Summary of the invention

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

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

[0007] Since the sensing characteristics of the sensing optical fiber require rapid and accurate perception of parameter signals for changes in the external environment, the sensing optical fiber 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, a protective cover is usually set outside the sensing optical fiber. Although this protective cover protects the sensing optical fiber, it has an isolation and shielding effect on changes in the sensing parameters, resulting in insensitive and ineffective sensor feedback.

[0008] In the present application, a plurality of wall holes penetrating the wall of the protective tube are provided at intervals along the axial direction on the surface of the protective tube, so that the sensing optical fiber can directly contact the environment to be measured through the wall holes of the protective cover. Sensitive changes in the external environment such as temperature, humidity, vibration, etc. can be sensed to the sensing optical fiber through the wall holes, thereby improving the measurement accuracy of the sensing light unit. At the same time, since the protective cover provides protection for the sensing optical fiber, the sensing optical fiber is not easily damaged.

[0009] In some embodiments, fiber paste is not filled between the protective tube and the sensing optical fiber. In the present application, fiber paste is not filled between the protective tube and the sensing optical fiber, which can also prevent the sensing optical fiber from being damaged by the laser focal point at the wall hole when the fiber paste is transported. At the same time, the isolation of the sensing optical fiber from the environment to be measured by the fiber paste is reduced, and the sensitivity of the sensing optical unit is improved.

[0010] In some embodiments, the spacing between adjacent wall holes is 10 to 20 mm. Since the main function of the protective tube is to provide protection for the sensing optical fiber, the provision of wall holes 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 spacing between the wall holes should not be too close, nor too far. Too far will affect the full contact between the sensing optical fiber and the environment to be measured, affecting the accuracy of the measurement of the sensing optical fiber. The spacing between adjacent wall holes within this range can allow the sensing optical fiber to fully contact the environment to be measured, while reducing the impact of the wall holes 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 protection tube is in a through state, there is stress concentration at the edge of the wall hole, and the protection tube is prone to deformation and breakage. The wall hole with a sharp angle is more likely to produce stress concentration at the angle turning point, thereby affecting the strength of the protection tube. Therefore, using a circular or elliptical shape can evenly disperse the stress on the wall hole, reduce stress concentration, and improve the strength of the protection tube.

[0012] In some embodiments, the shape of the wall hole is circular, wherein the diameter of the circular wall hole is 0.1-0.4 mm, and the size of the wall hole will affect the strength of the protection tube and the contact between the sensing optical fiber and the environment to be measured. When the wall hole size is within this range, the impact on the strength of the protection tube can be reduced while making the contact between the sensing optical fiber and the environment to be measured more complete; and / or,

[0013] The shape of the wall hole is an ellipse, wherein the length of the short axis of the ellipse is 0.1 to 0.4 mm, and the length of the long axis of the ellipse is 0.2 to 0.6 mm. The size of the wall hole will affect the strength of the protective tube and the contact between the sensing optical fiber and the environment to be measured. When the wall hole size is within this range, it can reduce the impact on the strength of the protective tube while making the contact between the sensing optical fiber and the environment to be measured more complete. It should be noted that, further, when the shape of the wall hole is an ellipse, 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, the impact of the wall hole on the strength of the protective tube can be further reduced.

[0014] In some embodiments, the sum of the areas of the multiple wall holes is S1, and the side area of ​​the protective tube is S2, wherein 1%≤S1 / S2≤10%. Since the protective tube is provided with wall holes, the existence of the wall holes will 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 ensure sufficient contact between the sensing optical fiber and the environment to be measured while retaining the protective strength of the protective tube, the area of ​​the wall holes is within this range, which can both reduce the impact 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 protection tube is 1.8-3.5 mm. The outer diameter of the protection tube has a greater influence 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 is opened, which is conducive to improving the strength of the protection tube; and / or,

[0016] The thickness of the protection tube is 0.10-0.25 mm. The thicker the protection tube is, the greater its strength is, and the smaller the effect of the wall holes on the strength of the protection tube is, but the cost and weight are also greater. The thickness of the protection tube within this range can reduce the effect of the wall holes on the strength of the protection tube; and / or,

[0017] The material of the protection tube includes stainless steel. Stainless steel has the characteristics of good protection strength, salt resistance and corrosion resistance, is more adaptable to changeable measurement environments, and provides protection for optical fibers. At the same time, due to its own good strength, it can reduce the impact of wall holes on the strength of the protection tube.

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

[0019] In a second aspect, the present application proposes a method for preparing a photosensitive unit, which is used to prepare the photosensitive unit of the first aspect of the present application, comprising the following steps:

[0020] A plurality of half-wall holes are formed at corresponding positions on both sides of the plate of the protection tube;

[0021] Wrapping the sensing optical fiber in a protective tube formed by the protective tube sheet to obtain a sensing optical unit;

[0022] The shapes of the multiple half-wall holes are enclosed to form the wall hole of the protection tube.

[0023] A protective tube is formed by forming a plurality of half-wall holes at corresponding positions on both sides of the plate of the protective tube, and the wall holes of the protective tube are formed by enclosing the protective tube plate. The forming of the wall holes can be completed at the steel plate stage, and there is no need to further shape the protective tube after wrapping the sensing optical fiber, which can reduce the number of steps and reduce damage to the sensing optical fiber.

[0024] In some embodiments, in the method of forming a plurality of half-sub-wall holes at corresponding positions on both sides of the plate of the protective tube, the method of forming the plurality of half-sub-wall holes includes cutting the plurality of half-sub-wall holes on both sides of the steel plate in a corresponding manner using the special-shaped concave and convex openings of the cutter. The special-shaped concave and convex openings of the cutter are used to cut the corresponding shapes when the steel plate is cut, and the wall holes are formed when welding, thereby avoiding the problem of conventional punching methods such as mechanical punching having many burrs on the edges of the holes, which is prone to pipe breakage during production. A special design is made on the cutter mold without adding any process steps, and the aperture is uniform and controllable.

[0025] In some embodiments, the plate material of the protection tube is first welded and then stretched to form the protection tube. 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 protective tube during stretching is 1.1 to 1.3 times the moving speed of the protective tube during welding, which can reduce the influence of stress release on the protective tube caused by the existence of wall holes during the stretching stage, eliminate potential hidden dangers, and reduce the influence of wall holes on the strength of the protective tube; and / or,

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

[0028] 8.8m / min≤V2≤19.5m / min. The moving speed of the protective tube during stretching is within this range, which can make the stress of the protective tube more fully released and improve the strength of the protective tube.

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

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. 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 paying any creative work.

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

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

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

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

[0035] Figure 5 This is a flow chart of an embodiment of a method for preparing 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 preparing 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] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present 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 the monitoring of various physical quantities such as temperature, pressure, and displacement.

[0043] The core of optical fiber for sensing is that it can convert the changes of external physical quantities into the changes of physical characteristic parameters of light waves, and sense external signals by measuring the changes of these parameters. Specifically, optical fiber for sensing can modulate and demodulate parameters such as light intensity, wavelength, frequency, phase and polarization state, thereby realizing the measurement of various physical quantities.

[0044] However, existing optical fibers for sensing generally have the problem of insufficient sensing precision, which affects the accuracy of measurement.

[0045] In view of this, the present application provides a sensing light unit to solve the problem of insufficient sensing precision commonly found in existing sensing optical fibers, which affects the accuracy of measurement.

[0046] First, as Figure 1 and Figure 2 As shown, the present application provides a photosensitive unit 100, comprising a protective tube and a sensing optical fiber 2 located in the protective tube, wherein a plurality of wall holes 11 penetrating the tube wall of the protective tube are provided on the surface of the protective tube at intervals along the axial direction.

[0047] Since the sensing characteristics of the sensing optical fiber 2 require rapid and accurate perception of parameter signals for 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 cover is usually provided on the outside of the sensing optical fiber 2. Although this protective cover protects the sensing optical fiber 2, it has an isolation and shielding effect on changes in the sensing parameters, resulting in insensitive and ineffective sensor feedback.

[0048] In the present application, a plurality of wall holes 11 penetrating the wall of the protective tube are provided at intervals along the axial direction on the surface of the protective tube, so that the sensing optical fiber 2 can directly contact the environment to be measured through the wall holes 11 of the protective cover. Sensitive changes in the external environment such as temperature, humidity, vibration, etc. can be sensed to the sensing optical fiber 2 through the wall holes 11, thereby improving the measurement accuracy of the sensing light unit 100. At the same time, since the protective cover provides protection for the sensing optical fiber 2, the sensing optical fiber 2 is not easily damaged.

[0049] It should be noted that if Figures 1 to 4As shown, in some embodiments of the present application, the shape of the wall holes 11 is not limited, for example, it can be various shapes such as square, circular, triangular, polygonal, etc. In some embodiments of the present application, the arrangement of the wall holes 11 is also not limited, for example, the wall holes 11 of various shapes can be randomly arranged, or the wall holes 11 of the same shape can be evenly arranged, which can be selected according to actual needs. In some embodiments of the present application, the wall holes 11 can be arranged in only one row or in multiple rows along the axial direction. When multiple rows are arranged, they can be distributed with equal spacing or with non-equal spacing.

[0050] In combination with the first aspect, in some embodiments provided in the present application, fiber paste is not filled between the protection tube and the sensing optical fiber. In the present application, fiber paste is not filled between the protection tube 1 and the sensing optical fiber 2, which can also prevent the sensing optical fiber 2 from being damaged by the laser focal point at the wall hole 11 when the fiber paste is transported. At the same time, the isolation of the sensing optical fiber 2 from the environment to be measured by the fiber paste is reduced, and the sensitivity of the sensing optical unit 100 is improved.

[0051] In combination with the first aspect, in some embodiments provided in the present application, the spacing between adjacent wall holes 11 is 10 to 20 mm. Since the main function of the protective tube is to provide protection for the sensing optical fiber 2, the provision of the wall holes 11 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 spacing of the wall holes 11 should not be too close, nor too far. Too far will affect the full contact between 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 spacing between adjacent wall holes 11 within this range can make the sensing optical fiber 2 fully contact with the environment to be measured, while reducing the impact of the wall holes 11 on the structural strength of the protective tube. The spacing 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] Combined with the first aspect, Figure 3 and 4 As shown, in some embodiments provided in the present application, the shape of the wall hole 11 is circular or elliptical. Since the wall hole 11 on the protection tube is in a through state, there is stress concentration at the edge of the wall hole 11, and the protection tube is prone to deformation and breakage. The wall hole 11 with a sharp angle is more likely to produce stress concentration at the angle turning point, thereby affecting the strength of the protection tube. Therefore, using a circular or elliptical shape can evenly disperse the stress on the wall hole 11, reduce stress concentration, and improve the strength of the protection tube.

[0053] In combination with the first aspect, in some embodiments provided in the present application, the shape of the wall hole 11 is circular, wherein the diameter of the circular wall hole 11 is 0.1-0.4 mm, and the size of the wall hole 11 will affect the strength of the protection tube and the contact between the sensing optical fiber 2 and the environment to be measured. When the size of the wall hole 11 is within this range, the impact on the strength of the protection tube can be reduced while making the contact between the sensing optical fiber 2 and the environment to be measured more sufficient. 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 combination with the first aspect, in some embodiments provided in the present application, the shape of the wall hole 11 is an ellipse, wherein the length of the short axis of the ellipse is 0.1 to 0.4 mm, and the length of the long axis of the ellipse is 0.2 to 0.6 mm. The size of the wall hole 11 will affect the strength of the protective tube and the contact between the sensing optical fiber 2 and the environment to be measured. When the size of the wall hole 11 is within this range, it can reduce the impact on the strength of the protective tube while making the contact between the sensing optical fiber 2 and the environment to be measured more sufficient. It should be noted that, further, when the shape of the wall hole 11 is an ellipse, 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 impact of the wall hole 11 on the strength of the protective tube can be further reduced. The length of the short axis of the ellipse 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 major axis of the ellipse 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 combination with the first aspect, in some embodiments provided in the present application, the sum of the areas of the plurality of wall holes 11 is S1, and the side area of ​​the protection tube is S2, wherein 1%≤S1 / S2≤10%. Since the protection tube is provided with the wall holes 11, the existence of the wall holes 11 will affect the strength of the protection tube, and the strength of the protection tube affects the service life of the optical fiber. In order to simultaneously meet the full contact between the sensing optical fiber 2 and the environment to be measured and retain the protective strength of the protection tube, the area of ​​the wall holes 11 is within this range, which can reduce the influence of the wall holes 11 on the strength of the protection tube and increase the contact between the sensing optical fiber 2 and 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 combination with the first aspect, in some embodiments provided in the present application, the outer diameter of the protection tube is 1.8 to 3.5 mm. The outer diameter of the protection tube has a greater influence 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 beneficial 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 combination with the first aspect, in some embodiments provided in the present application, the thickness of the protection tube is 0.10-0.25 mm. The thicker the protection tube is, the greater the strength is, and the smaller the effect of the wall hole 11 on the strength of the protection tube is, but the cost and weight are also greater. When the thickness of the protection tube is within this range, the effect 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 combination with the first aspect, in some embodiments provided in the present application, the material of the protection tube includes stainless steel, which has the characteristics of good protection strength, salt resistance and corrosion resistance, is more adaptable to variable measurement environments, and provides protection for the optical fiber. At the same time, due to its own good strength, it can reduce the influence of the wall hole 11 on the strength of the protection tube. The stainless steel can be selected from 304 or 316 stainless steel.

[0059] It should be noted that, in some embodiments of the present application, the wall holes 11 on the protective tube may be arranged uniformly or unevenly in a single row along the axial direction of the protective tube. In other embodiments of the present application, the wall holes 11 on the protective tube may be arranged uniformly or unevenly in multiple rows along the axial direction of the protective tube. The selection can be made according to actual use requirements. The wall holes 11 on the protective tube may be arranged uniformly in a single row along the axial direction of the protective tube, which is easier to form, such as cutting the steel plate with a cutter and then welding it. The wall holes 11 on the protective tube may be arranged unevenly in multiple rows along the axial direction of the protective tube, so that the stress is less likely to concentrate in the same direction, and the impact on the strength of the protective tube can be reduced. Multiple wall holes 11 can be formed on the protective tube by laser drilling, but this method has the risk of damaging the sensing optical fiber 2.

[0060] Second, as Figure 5 As shown, the present application proposes a method for preparing a light sensing unit 100, which is used to prepare the light sensing unit 100 of the first aspect of the present application, comprising the following steps:

[0061] S10, forming a plurality of half-wall holes at corresponding positions on both sides of the plate of the protection tube;

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

[0063] The shapes of the multiple half-wall holes are enclosed to form the wall hole of the protection tube.

[0064] A plurality of half-wall holes 11 are formed at corresponding positions on both sides of the plate of the protective tube, and the protective tube is formed by enclosing the protective tube plate. The wall holes 11 of the protective tube are enclosed by the shapes of the plurality of half-wall holes 11. The forming of the wall holes 11 can be completed at the steel plate stage. After wrapping the sensing optical fiber 2, there is no need to further shape the protective tube, which can reduce the number of steps and reduce damage to the sensing optical fiber 2.

[0065] Combined with the second aspect, such as Figures 6 to 8 As shown, in some embodiments provided in the present application, in the method of forming the shapes of multiple half-sub-wall holes 11 at corresponding positions on both sides of the plate of the protective tube, the method of forming the shapes of multiple half-sub-wall holes 11 includes using a corresponding manner of the special-shaped concave and convex openings of a cutter to cut the shapes of multiple half-sub-wall holes 11 on both sides of the steel plate. The special-shaped concave and convex openings of the cutter are used to cut out corresponding shapes when the steel plate is cut, and the wall holes 11 are formed during welding, thereby avoiding the problem of conventional punching methods such as mechanical punching with many burrs on the edges of the holes, which is prone to tube breakage during production. Special designs are made on the cutter mold without adding additional process steps, and the aperture is uniform and controllable. The position, size and number of the cutter's concave and convex openings can control the size of the position and shape of the wall holes 11 in the protective tube.

[0066] In combination with the second aspect, in some embodiments provided in the present application, the plate material of the protection tube 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: 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 effect of stress release on the protection tube causing the tube to break during the stretching stage due to the existence of the wall hole 11, eliminate potential hidden dangers, and reduce the effect 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] In combination with the second aspect, in some embodiments provided in the present application, the sheet material of the protection tube 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: 8m / min≤V1≤15m / min. Since the protection tube is provided with a wall hole, the wall hole will have a certain impact on the strength of the protection tube. Therefore, it is necessary to control the moving speed of the protection tube during welding and the moving speed of the welded tube during stretching. When the moving speed of the protection tube during welding is within this range, stable welding quality and stable welded tube forming effect can be obtained, ensuring that the welded tube production can be carried out continuously and smoothly, and the deviation of the stainless steel strip caused by speed during welding and the breakage of the welded tube at the wall hole can be reduced. The moving speed V1 of the protection tube during welding includes but is not limited to 8m / min, 9m / min, 10m / min, 11m / min, 12m / min, 13m / min, 14m / min or 15m / min.

[0068] In combination with the second aspect, in some embodiments provided in the present application, the plate of the protection tube 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: 8.8m / min≤V2≤19.5m / min. When the moving speed of the protection tube during stretching is within this range, the outer diameter change effect can be obtained, the strength of the protection tube can be improved, and the probability of fracture of the welded tube at the wall hole and hole deformation during the stretching process can be reduced. The moving speed V2 of the protection tube during stretching includes but is not limited to 8.8m / min, 9.0m / min, 9.5m / min, 10.0m / min, 11.0m / min, 12.0m / min, 13.0m / min, 14.0m / min, 15.0m / min, 16.0m / min, 17.0m / min, 18.0m / min, 19.0m / min or 19.5m / min.

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

[0070] In summary, by providing a plurality of wall holes penetrating the wall of the protective tube at axial intervals on the surface of the protective tube, and without filling fiber paste between the protective tube and the sensing optical fiber, the sensing optical fiber can directly contact the environment to be measured through the wall holes of the protective cover, and sensitive changes in the external environment such as temperature, humidity, vibration, etc. can be sensed to the sensing optical fiber through the wall holes, thereby improving the measurement accuracy of the sensing light unit. At the same time, because the protective cover provides protection for the sensing optical fiber, the sensing optical fiber is not easily damaged.

[0071] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0072] It should be noted that, in the present application, relational 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 that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically stipulated.

[0073] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to 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 the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A light sensing unit, characterized in that: The invention comprises a protection tube and a sensing optical fiber located in the protection tube, wherein a plurality of wall holes penetrating the tube wall of the protection tube are arranged at intervals along the axial direction on the surface of the protection tube.

2. The light sensing unit according to claim 1, characterized in that: 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 to 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 to 0.4 mm; and / or, The shape of the wall hole is an ellipse, wherein the length of the minor axis of the ellipse is 0.1-0.4 mm, and the length of the major axis of the ellipse is 0.2-0.6 mm.

5. The light sensing unit according to claim 1, characterized in that: 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 protection tube is 1.8 to 3.5 mm; and / or, The thickness of the protective tube is 0.10 to 0.25 mm; and / or, The material of the protection tube includes stainless steel.

7. A method for preparing a photosensitive 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 sheet 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, characterized in that: 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 cutting knife with corresponding shaped concave and convex openings to cut multiple half-wall hole shapes on both sides of the steel plate.

9. The light sensing unit according to claim 7, characterized in that: The protective tube is formed by welding the plates first and then stretching them. 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 protection tube during welding is V1, 8m / min≤V1≤15m / min.

10. A measuring device, characterized in that: Comprising the light sensing unit as claimed in any one of claims 1 to 6.

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