JP2007218653A - Liquid substance detection sensor, liquid substance detection method and composite material structure forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid substance detection sensor easy to process and reduced in the irregularity of the response characteristics of light. <P>SOLUTION: The liquid substance detection sensor 21 is equipped with a first light path 22 for transmitting the light emitted from a light source 25, a curved part (light scattering part) 23 for scattering the light transmitted through the first light path 22 to the outside and a second light path 24 for transmitting the light penetrated from the curved part 23. The first light path 22, the curved part 23 and the second light path 24 are constituted of a light transmitting material, the scattering quantity of light to the outside in the curved part 23 is larger than the scattering quantity of light to the outside in the first light path 22 or the scattering quantity of light to the outside in the second light path 24. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sensor for detecting a liquid substance, and in particular, a liquid substance detection sensor and a liquid substance detection method capable of grasping the impregnation state during an impregnation operation in which a liquid resin is vacuum impregnated into a fiber base material. Furthermore, the present invention relates to a method for forming a composite structure provided with such a liquid substance detection sensor.

  In recent years, composite materials such as FRP (Fiber Reinforced Plastic) and CFRP (Carbon Fiber Reinforced Plastic) as materials having light weight and high strength have been used in aircraft main wings, ships, large windmill rotors, railway vehicles, and construction fields. Widely used in various fields including structural members. FRP, CFRP (hereinafter simply referred to as FRP) is a resin such as a thermosetting resin in a state in which a reinforcing fiber substrate such as glass fiber or carbon fiber or a mat-like reinforcing fiber substrate is molded by a mold. Is impregnated and cured to form a predetermined shape.

Here, a member formed by FRP (hereinafter referred to as FRP member) is required to have a predetermined strength. The strength of the FRP member is ensured by reliably impregnating the reinforcing fiber base with resin.
Therefore, in particular, in the field where FRP members are industrially produced, a device has been devised for reliably impregnating a reinforcing fiber base with a resin during molding. As one of such devices, a reinforcing fiber substrate is placed on a mold, covered with a bag material, and then the space surrounded by the bag material and the mold is sucked with a vacuum pump or the like to reduce the pressure (negative pressure). And a vacuum bag method in which resin is introduced into this space (for example, see Patent Document 1).

  Here, an example of a technique for manufacturing a large FRP product by the vacuum bag method will be described with reference to FIG. As shown in FIG. 7, a laminated body of reinforcing fiber base materials 3 is installed on the upper surface of the mold 1, and the pass media 2 is laid thereon. The pass media 2 is a sheet made of a net or cloth having a large number of voids, and the liquid resin can be rapidly permeated and diffused into a plane along the surface of the pass media 2.

  A resin supply pipe 4 is disposed at the center of the upper surface of the pass media 2. The resin stored in the resin storage tank 8 is supplied to the resin supply pipe 4. Then, the bag film 5 is covered from the upper surface of the reinforcing fiber base 3 including the pass media 2 and the resin supply pipe 4. The periphery of the bag film 5 and the mold 1 are sealed.

  The suction pipe 6 has a distal end that penetrates the seal and faces the reinforcing fiber base 3, and a vacuum suction device 7 is connected to the proximal end of the suction pipe 6 to decompress the interior of the bag before resin supply.

  When the resin is impregnated, the liquid resin is supplied to the resin supply pipe 4 while maintaining the reduced pressure inside the bag while operating the vacuum suction device 7. Then, the liquid resin is supplied from the resin supply pipe 4 to the pass medium 2 and rapidly permeates and diffuses into the surface along the surface of the pass medium 2. Thus, the liquid resin diffused in a planar shape by the pass media 2 is impregnated (vacuum impregnated) from the upper surface side of the reinforcing fiber base 3.

  A large FRP product has a large area to be impregnated with resin, and therefore cannot impregnate the entire product in a lump. This is because if the resin is impregnated over a wide area, the resin non-impregnated portion is generated over a wide area, or the gas expelled by the resin impregnation remains in various places on the wide surface.

  Therefore, in order to obtain a high-quality FRP having no unimpregnated portion, it is necessary to grasp the flow state of the liquid resin and control the timing of resin injection. Therefore, a sensor for grasping the flow state of the liquid resin has an important role for obtaining a high-quality FRP, and attempts have been made to detect the resin flow using various sensors.

A dielectric sensor is known as one of sensors that detect liquid resin. FIG. 9 is a diagram illustrating a configuration of the dielectric sensor 10. The dielectric sensor 10 is configured by arranging wirings 11 and 12 on a plastic film 13. The wiring 11 is connected to the + terminal of the power supply 14, and the wiring 12 is connected to the − terminal of the power supply 14. When the dielectric sensor 10 is disposed between the reinforcing fiber bases and impregnated with resin, the liquid resin comes into contact with the wirings 11 and 12 of the dielectric sensor 10, and current flows through the circuit due to ions in the resin. At this time, the presence of the resin can be detected by detecting the potential difference generated in the circuit with the voltmeter 15. In addition, it is possible to detect the curing state of the resin by utilizing the fact that the ions decrease and the current decreases as the resin cures.
However, since the dielectric sensor 10 is a film having a predetermined area, it becomes an obstacle to resin impregnation. Moreover, when it arrange | positions between the carbon reinforced fiber base materials which have electroconductivity, there existed a possibility that a circuit might short-circuit.

A liquid substance detection sensor that does not have the above problems is disclosed in Patent Document 2. The liquid substance detection sensor has a first optical fiber having an emission surface for emitting light at or near the tip, and an incident surface for receiving light emitted from the first optical fiber at the tip or tip. It is comprised from the 2nd optical fiber which has in the vicinity. Since this liquid substance detection sensor uses an optical fiber having a small wire diameter, there is almost no hindrance to resin impregnation even if it is disposed between reinforcing fiber substrates. Moreover, since the response of light is used, there is no problem in using the carbon reinforcing fiber base.
In the liquid substance detection sensor, when no resin is present between the exit surface of the first optical fiber and the entrance surface of the second optical fiber, the light emitted from the first optical fiber is transmitted to the second optical fiber. However, when resin is present, light is also incident on the second optical fiber due to a change in refractive index, and the presence of the resin can be detected.
However, in the liquid substance detection sensor of Patent Document 2, it is not easy to precisely process the exit surface of the first optical fiber and the entrance surface of the second optical fiber. In particular, the reflection of light in this liquid substance detection sensor is due to projections that are unintentionally produced when the exit surface is processed, there is variation in the response characteristics of light, and the detection reliability of liquid substances is insufficient. It is. In order to control the response characteristics of light, it is not easy to process the shape of the protrusion into a desired shape.

  The applicant of the present application has also proposed a resin impregnation sensor in Patent Document 3, but this resin impregnation sensor detects the resin impregnation visually and has a complicated structure.

JP 2003-11136 A JP 2001-27678 A JP 2004-203021 A

  The present invention has been made based on such a technical problem, and an object of the present invention is to provide a liquid substance detection sensor that is easy to process and manufacture and has little variation in light response characteristics. The present invention also provides a liquid substance detection method using such a liquid substance detection sensor. Furthermore, the present invention provides a method of forming a composite material structure such as FRP while using such a liquid substance detection sensor.

For this purpose, the liquid substance detection sensor of the present invention includes a first optical path for transmitting light supplied from a light source, a light scattering portion for scattering the light transmitted through the first optical path to the outside, and And a second optical path for transmitting the light that has entered from the light scattering portion to a predetermined position. The first light path, the light scattering part, and the second light path are made of an integral linear material made of a light-transmitting material, and the amount of light scattering to the outside in the light scattering part is determined in the first light path. It is characterized by being larger than the amount of scattered light to the outside or the amount of scattered light to the outside in the second optical path.
In the liquid substance detection sensor of the present invention, the amount of light scattered to the outside differs depending on whether the substance surrounding the light scattering portion is the atmosphere or a liquid substance. Utilizing this property, the liquid substance detection sensor of the present invention detects the presence of the liquid substance. By increasing the amount of light scattering to the outside in the light scattering portion more than the amount of light scattering to the outside in the first optical path or the amount of light scattering to the outside in the second optical path, In some cases, the difference in the amount of scattered light to the outside can be clarified.

  In the liquid substance detection sensor of the present invention, the first light path, the light scattering portion, and the second light path can be formed of an integral linear material, so that processing and production are easy. For example, the liquid substance detection sensor of the present invention can be manufactured by a simple process of bending a single linear material made of a light transmissive material at a predetermined position. The bent portion constitutes a light scattering portion, one linear portion having the bent portion as a boundary constitutes the first optical path, and the other linear portion constitutes the second optical path. Further, in the bent liquid detection sensor, the light scattering portion is different in the light transmission direction from the first optical path. Thus, the scattering of light to the outside is promoted by utilizing the fact that the light transmission direction is different. Furthermore, it is easy to control the angle of bending, and the amount of light scattering to the outside can be specified by the angle of bending, so that the liquid substance detection sensor according to the present invention has variations in light response characteristics. Can be reduced.

  When a single linear member made of a light transmissive material is bent by approximately 180 °, the first optical path and the second optical path are provided substantially in parallel. According to this aspect, it is possible to sufficiently ensure the scattering of light to the outside in the light scattering portion.

In the liquid substance detection sensor of the present invention, it is preferable that the surfaces of the first optical path and the second optical path are covered with a light-shielding material or a transmissive material having a refractive index smaller than that of the material serving as the optical path. The purpose of the first optical path and the second optical path is to transmit light, and to prevent the scattering of light to the outside is to clarify the difference in the amount of scattered light from the light scattering section. It is because it is preferable.
In addition, although the above “bending” is supposed to process a linear one, for example, it is also possible to produce one that is bent from the beginning by injection molding. Such forms are also included.

  The present invention provides a method for detecting the presence of a liquid substance with a sensor. In this liquid substance detection method, the sensor is made of a light-transmitting material, and includes a linear first optical path, a curved portion connected to the first optical path, and a linear shape connected to the curved portion. A second optical path is provided. The presence of the liquid substance can be detected by monitoring fluctuations in the intensity of light emitted from the second optical path while supplying light of a predetermined intensity to the first optical path of the sensor.

  The liquid substance detection method of the present invention can detect the presence of a liquid substance using one of the above-mentioned sensors, but arranges a plurality of sensors at a predetermined interval and monitors fluctuations in light intensity in each sensor. Thus, it can be detected whether the liquid material has sequentially reached the predetermined position.

The present invention is applied to formation of FRP, and a novel method for forming a composite material structure having a predetermined shape with a composite material containing reinforcing fibers and a resin is provided. In this method, the reinforcing fiber base is covered with an airtight sheet having airtightness in a state where the reinforcing fiber base is placed on the surface of a mold having a shape corresponding to the composite structure, and the outer peripheral portion of the airtight sheet is covered. A step of hermetically sealing against the mold and forming a molding region; a step of reducing the molding region in the hermetic sheet; and a step of injecting resin into the molding region and impregnating the reinforcing fiber base with resin. And in the step of impregnating the resin, the impregnation state of the resin is monitored by a plurality of resin detection sensors arranged in the molding region and in the resin impregnation direction, and the resin detection sensor is made of a light transmissive material, An optical path, a curved portion connected to the first optical path, and a second optical path connected to the curved portion, and supplying light of a predetermined intensity to the first optical path, from the second optical path Due to fluctuations in the intensity of the emitted light, Characterized by monitoring the immersion situation.
In the above composite material structure forming method, since a plurality of resin detection sensors are arranged in the resin impregnation direction, it is possible to grasp whether the resin impregnation is proceeding properly. In addition, the resin detection sensor has a very simple configuration including a first optical path, a curved portion connected to the first optical path, and a second optical path connected to the curved portion, and uses light. Therefore, unlike the dielectric sensor, the resin impregnation state can be properly grasped even if the reinforcing fiber base is made of conductive carbon fiber.

  As described above, according to the present invention, there is provided a liquid substance detection sensor that is easy to process and has little variation in light response characteristics. Since this liquid substance detection sensor can be comprised from a linear material, the grade which inhibits resin impregnation is remarkably low compared with a dielectric sensor. Moreover, since the liquid substance detection sensor of this invention uses light, it does not raise | generate an electrical short circuit with respect to carbon fiber.

<First Embodiment>
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 1 is a diagram showing a schematic configuration of a liquid material detection apparatus 20 including a liquid material detection sensor 21 in the present embodiment. As shown in FIG. 1, the liquid material detection device 20 receives a liquid material detection sensor 21, a light source 25 that supplies light to the liquid material detection sensor 21, and light transmitted through the liquid material detection sensor 21. And a photodetector 26 for detecting the intensity.

  The liquid substance detection sensor 21 is composed of an acrylic fiber. The light supplied from one end of the acrylic fiber is scattered or attenuated outside the acrylic fiber, but is emitted from the other end. The degree of light scattering outside the acrylic fiber varies depending on the environment surrounding the acrylic fiber. The liquid substance detection sensor 21 according to the present embodiment uses this property to detect the presence of a liquid substance, for example, a liquid resin.

The liquid substance detection sensor 21 is composed of three parts: a first optical path 22, a curved part (light scattering part) 23, and a second optical path 24. The first optical path 22, the curved portion 23, and the second optical path 24 are formed by bending an integral acrylic fiber.
The first optical path 22 is a part that transmits light supplied from the light source 25 to the bending portion 23. As shown in FIG. 1, the first optical path 22 extends linearly. Therefore, there is little scattering of the light transmitted through the first optical path 22 to the outside. The first optical path 22 may be bent, but a straight line with less light scattering is more advantageous for liquid substance detection.

  The light transmitted through the first optical path 22 enters the bending portion 23. The light that has entered the bending portion 23 is transmitted through the bending portion 23, but has a component that is reflected by the outer peripheral surface of the acrylic fiber that constitutes the bending portion 23 and a component that is scattered outside. The liquid substance detection sensor 21 according to the present embodiment is provided with a curved portion 23 in order to intentionally scatter light to the outside. As described above, the degree of light scattering in the bending portion 23 varies depending on the substance existing around the bending portion 23.

  The light transmitted through the bending portion 23 enters a second optical path 24 that is arranged in parallel with the first optical path 22. The light that has entered the second optical path 24 is transmitted through the second optical path 24 and supplied to the photodetector 26. Since the second optical path 24 is also linear, light scattering outside the transmission process is less than that of the curved portion 23. A photoelectric conversion element such as a photodiode can be used as the photodetector 26, and the photodetector 26 can detect a voltage corresponding to the intensity of light emitted from the second optical path 24.

Next, the principle of detection of the liquid substance by the liquid substance detection sensor 21 will be described with reference to FIG.
The upper part of FIG. 2 shows the case where the periphery of the bending part 23 is air, and the lower part of FIG. 2 shows the case where the periphery of the bending part 23 is a liquid substance. As will be described below, there is a difference in the intensity of light transmitted through the second optical path 24.
It is assumed that the intensity of light transmitted through the first optical path 22 and entering the bending portion 23 is the same in both the upper stage of FIG. 2 and the lower stage of FIG. In the upper part of FIG. 2 and the lower part of FIG. 2, part of the light transmitted through the bending part 23 is scattered from the bending part 23 to the outside. The scattering of light to the outside is caused by the refractive index on the outer surface of the curved portion 23 in the lower portion of FIG. 2 where the periphery of the curved portion 23 is a liquid substance, compared to the upper portion of FIG. Will increase in relation to. Therefore, the intensity of the light transmitted through the second optical path 24 is relatively large in the upper part of FIG. 2 where the surrounding is the atmosphere, and is relatively small in the lower part of FIG.
Therefore, when the surroundings change from an atmospheric state to a liquid material, the voltage output from the photodetector 26 becomes low. By this change in voltage, the liquid material detection device 20 can detect the presence of the liquid material.

The liquid material that is detected by the liquid material detection device 20 is not limited. In addition to the liquid resin used for the FRP preparation described above, it includes a wide range of liquids, gels, slurries and the like. In addition, examples of the resin include thermosetting resins such as epoxy, unsaturated polyester, phenol, and vinyl ester, thermoplastic resins such as ABS resin, and a mixture of thermosetting resin and thermoplastic resin.
In the case where the liquid is solidified, the solidification status can be grasped. For example, in the process from the liquid state to the completion of curing of the resin, the refractive index of the resin changes with the curing of the resin, so that the detected light intensity changes. By measuring this change in light intensity, the curing state of the resin can be grasped.

  Although the above liquid substance detection sensor 21 is produced by bending an acrylic fiber by approximately 180 °, the present invention is not limited to this form. As described above, since the bending portion 23 is provided to promote the scattering of light to the outside, it is possible to promote the scattering of light to the outside as compared with the first optical path 22. For example, the present invention allows as long as processing and fabrication are possible. For example, the form shown in FIG. That is, in the liquid substance detection device 30 in FIG. 3A, the first light path 32 supplied from the light source 35 and the light transmitted through the first light path 32 enter as in the liquid detection device 20 described above. The liquid substance detection sensor 31 including the bending portion (light scattering portion) 33, the second optical path 34 through which the light transmitted through the bending portion 33 enters, and the light transmitted through the second optical path 34 are supplied. The optical detector 36 is provided, and the bending portion 33 is formed by bending an acrylic fiber by approximately 90 °.

In the liquid substance detection sensor 21 described above, the first optical path 22 and the second optical path 23 are provided side by side, and the light source 25 and the photodetector 26 can be provided side by side. FIG. It can also be set as the form shown in. That is, in the liquid substance detection device 40 of FIG. 3B, the light transmitted from the first light path 42 and the first light path 42 supplied from the light source 45 enters, as in the liquid detection device 20 described above. The liquid substance detection sensor 41 including the bending portion (light scattering portion) 43, the second optical path 44 through which the light transmitted through the bending portion 43 enters, and the light transmitted through the second optical path 44 are supplied. The photo detector 46 is provided, and the bending portion 43 is formed by twisting the acrylic fiber once, that is, by bending 360 °.
In addition, the present invention functions even when the curved portion has an elliptical shape, a polygonal shape, or the like.

Although the above liquid substance detection sensor 21 showed the example comprised by the acrylic fiber, as long as the 1st optical path 22, the curved part 23, and the 2nd optical path 24 can transmit light, what kind of material will be sufficient as it. Can be used. For example, a liquid substance detection sensor can be constituted by an optical fiber. An example is shown in FIG. The liquid substance detection sensor 51 shown in FIG. 4 has the same basic configuration as the liquid substance detection sensor 21, that is, the liquid substance detection sensor 51 has a first optical path 52 that receives light supplied from a light source, A curved portion (light scattering portion) 53 into which light transmitted through the first optical path 52 enters, and a second optical path 54 through which light transmitted through the curved portion 53 enters. In the liquid substance detection sensor 51, the first optical path 52, the bending portion 53, and the second optical path 54 are configured by optical fibers. The optical fiber is composed of a core and an outer layer covering the periphery of the core, and the outer layer does not transmit light. Therefore, in this embodiment, the outer layer is peeled off for a part of the bending portion 53. Accordingly, in the liquid substance detection sensor 51, the first optical path 52 includes the core 52a and the outer layer 52b covering the periphery thereof, and the second optical path 54 includes the core 54a and the outer layer 54b covering the periphery thereof. The bending portion 53 includes a core 53a and an outer layer 53b that covers a part of the periphery of the core 53a. Scattering of light to the outside occurs in a region where the outer layer 53 b does not exist in the curved portion 53.
For the outer layer, the outer layer is not removed if it loses its function as an outer layer of the optical fiber by bending it without removing it, that is, the function of reflecting light into the fiber and preventing it from going out. May be.
The optical fiber is advantageous in the case where the liquid substance detection sensor 51 is long because the attenuation of light during light transmission is smaller than that of the acrylic fiber. In addition, when using what has no surrounding coating, such as an acrylic fiber, coating with a paint or the like is effective for reducing light attenuation.

Second Embodiment
The liquid substance detection sensors 21, 31, 41, 51 described above constitute one sensor with one acrylic fiber or optical fiber (hereinafter sometimes referred to as a light transmission fiber). As shown in FIG. 5, a liquid substance detection sensor 61 including a plurality of sensors may be used.
The liquid substance detection sensor 61 includes sensor units 62, 63, 64, 65, and 66 and five sensor units. The sensor unit 62 includes a first optical path 62a, a curved portion 62b, and a second optical path 62c.
Similarly, the sensor part 63 is comprised from the 1st optical path 63a, the curved part 63b, and the 2nd optical path 63c. The sensor unit 64 includes a first optical path 64a, a bending section 64b, and a second optical path 64c. The sensor unit 65 includes a first optical path 65a, a bending section 65b, and a second optical path 65c. The sensor unit 66 includes a first optical path 66a, a curved part 66b, and a second optical path 66c.

Light is supplied from a light source (not shown) to the first light source 62a, and the supplied light is transmitted through the first optical path 62a and enters the bending portion 62b. The light transmitted through the curved portion 62b enters the second optical path 62c and is transmitted through the second optical path 62c.
The light transmitted through the second optical path 62 c of the sensor unit 62 enters the first optical path 63 a of the sensor unit 63. The light that has entered the first optical path 63a is transmitted through the first optical path 63a and enters the bending portion 63b. The light transmitted through the bending portion 63b enters the second optical path 63c and is transmitted through the second optical path 63c.
The light transmitted through the second optical path 63 c of the sensor unit 63 enters the first optical path 64 a of the sensor unit 64. The light that has entered the first optical path 64a is transmitted through the first optical path 64a and enters the bending portion 64b. The light transmitted through the curved portion 64b enters the second optical path 64c and is transmitted through the second optical path 64c.
Thereafter, the light supplied from the light source is sequentially transmitted through the sensor units 65 and 66, and is supplied to a photodetector (not shown) via the second optical path 66c of the sensor unit 66.

In the liquid substance detection sensor 61 described above, when the curved parts 62b to 66b of the sensor parts 62 to 66 are surrounded by the liquid substance, the amount of scattered light to the outside at each of the curved parts 62b to 66b is set to be different. Keep it. For example, if the amount of scattering of the light in the external in the bending portion 62b of the case surrounded by the liquid product and S _62, the amount of scattering of the external light when it is surrounded by liquid matter in the bending portion 62B～66b, the curved portion 63 b _{S 63,} the curved portion 64b _{S 64,} the curved portion 65b _{S 65,} the curved portion 66b constituting the bending portion 62b~66b so that _{S 66.} However, S ₆₂ ≠ S ₆₃ ≠ S ₆₄ ≠ S ₆₅ ≠ S ₆₆ . Thus, in order to make the amount of scattering of the light to the outside in the curved portions 62b to 66b different, the optical path lengths of the curved portions 62b to 66b may be made different. Alternatively, the amount of scattering of light when surrounded by the liquid material can be made different by coating the curved portions 62b to 66b with a paint and making the covered areas different.

Now, when all of the curved portions 62b to 66b are surrounded by the atmosphere, light having a predetermined intensity is input to the first optical path 62a and is passed through the second optical path 66c to a photodetector (not shown). Let L be the intensity of the light supplied. Under such assumption, only the curved portion 62b is When surrounded by liquid product, the intensity of the light supplied to the optical detector, the L-S _62. If only the curved portion 64b is surrounded by the liquid material, the intensity of light supplied to the photodetector is L- _S64 . Furthermore, assuming that the curved portions 63b and 65b are surrounded by a liquid material, the intensity of light supplied to the photodetector is L-S ₆₃ -S ₆₅ . Therefore, if the intensity of the light detected by the photodetector is L-S ₆₂ , and if the intensity of the light detected by the photodetector is L-S _{64 when} reaching the position of the curved portion 62b with the liquid material, Therefore, it can be determined that the liquid material has reached the position of the curved portion 64b. Furthermore, if the intensity of light detected by the photodetector is L-S ₆₃ -S _65, it can be determined that the liquid material has reached the position of the bending portion 63b and the position of the bending portion 65b.

  As described above, the liquid substance detection sensor 61 can detect the arrival state of the liquid substance at different positions on the same plane. In addition, the liquid substance detection sensor 61 has an advantage that it can detect the arrival state of the liquid substance at different positions on the same plane only by preparing one light source and one photodetector.

<Third Embodiment>
The third embodiment shows a specific application of the liquid substance detection sensor.
As described above, the present invention has been made for the purpose of detecting the resin impregnation state, but the liquid substance detection sensor can be widely applied not only to the detection of the resin impregnation state but also to the detection of the liquid substance. it can.
For example, FIG. 7 shows an example used for water level detection of a resin used in the vacuum bag method. That is, the liquid substance detection sensor 21 is installed at a predetermined height in the resin storage tank 8 in which the resin used for impregnation is stored.
If the bag film 5 is impregnated with the molten resin in the resin storage tank 8 while the bag film 5 is decompressed by the vacuum pump 7, the molten resin in the resin storage tank 8 is consumed. The liquid substance detection sensor 21 detects a change in the liquid level of the molten resin. The change in the liquid level can be detected by monitoring the change in the light intensity detected by the photodetector 26. By detecting the fluctuation of the liquid level, the molten resin is supplied into the resin storage tank 8 from a resin supply device (not shown) so that the amount of the molten resin in the resin storage tank 8 becomes constant. By doing so, the bag film 5 can be stably impregnated with the resin.

Hereinafter, the present invention will be described based on specific examples. In this embodiment, the liquid state detection sensor 21 having the form shown in FIG. 1 is used to detect the resin impregnation state of the laminate made of the reinforcing fiber base by the vacuum bag method, and further to detect the curing state of the impregnated resin. To do.
As shown in FIG. 6, liquid substance detection sensors 21 are installed at an interval of 100 mm on the upper surface of a 300 × 600 × 5 (mm) glass reinforcing fiber substrate 3 (5 laminated sheets) covered with a bag film 5. The resin arrival time at each point when the resin was introduced from the right side of FIG. 6 was measured. At this time, it arrange | positions so that the curved part (light-scattering part) 23 of the liquid substance detection sensor 21 may be located in the center part of the glass reinforcing fiber base material 3 in the width direction. Each liquid substance detection sensor 21 is accompanied by a light source 25 that supplies light to the first optical path 22 and a photodetector 26 that detects the intensity of light emitted from the second optical path 24. Then, simultaneously with the start of resin impregnation, light is supplied from the light source 25 to the first optical path 22 of each liquid substance detection sensor 21 and the intensity of the light emitted from the second optical path 24 is detected by the photodetector 26. Monitored.

In addition, the liquid substance detection sensor 21 processed the acrylic fiber of (phi) 2mm and length 800mm in the shape shown in FIG. A light source detector integrated amplifier unit (FS-12RM manufactured by Keyence) was used for the light source 25 and the light detector 26. When the liquid substance detection sensor 21 was connected and the amount of light in the atmosphere was measured, it was 1200 on a digital display.
A dielectric sensor was installed in the vicinity of the curved portion 23 of each liquid substance detection sensor 21, and the impregnation and curing conditions of the resin were monitored by two types of sensors, the liquid substance detection sensor 21 and the dielectric sensor. The result is shown in FIG. FIG. 8 shows one of a plurality of sensors. Actually, the diagram shown in FIG. 8 is obtained with a time difference corresponding to the number of sensors.

As shown in FIG. 8B, in the dielectric sensor, a current flows when the resin comes in contact with it, a voltage is generated, and the voltage decreases as the resin cures. It is known that the voltage becomes zero when the curing of the resin is completed.
On the other hand, as shown in FIG. 8A, in the liquid substance detection sensor 21, the light quantity history measured by the photodetector 26 is linked to the voltage history from the dielectric sensor. That is, it can be seen that the resin impregnated in the liquid substance detection sensor 21 comes into contact when the amount of light measured from the light detector 26 first begins to decrease due to resin impregnation. This is because the amount of light scattering to the outside increases when the curved portion 23 comes into contact with the resin. Thereafter, the amount of light measured from the photodetector 26 gradually decreases. This indicates that the resin is being cured. When the amount of light becomes constant, it indicates that the resin has been cured. As described above, also in the liquid substance detection sensor 21 manufactured using the acrylic fiber, the change in the light amount was detected at the same time as the voltage change of the dielectric sensor. Therefore, the change in the light intensity in the liquid substance detection sensor 21 is due to the contact and curing with the resin, and the effectiveness of the liquid substance detection sensor 21 was confirmed. Further, by arranging a plurality of liquid substance detection sensors 21, it is possible to grasp the progress of resin impregnation and resin curing in a predetermined region. The intensity of the light received by the photodetector 26 relative to the light supplied from the light source 25 to the liquid substance detection sensor 21 was 17% in the resin-impregnated state.

It is a figure which shows the structure of the liquid substance detection apparatus of 1st Embodiment. It is a figure for demonstrating the detection principle of the liquid substance detection apparatus of 1st Embodiment. It is a figure which shows the modification of 1st Embodiment. It is a figure which shows the other modification of 1st Embodiment. It is a figure which shows the structure of the liquid substance detection sensor of 2nd Embodiment. It is a figure which shows the resin impregnation detection method in an Example. It is a figure which shows the impregnation apparatus which performs resin impregnation by the vacuum back method in 3rd Embodiment. It is a graph which shows the detection result of resin in an Example. It is a figure which shows a dielectric sensor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 20 ... Liquid substance detection apparatus, 21, 31, 41, 51, 61 ... Liquid substance detection sensor, 22, 32, 42, 52 ... 1st optical path, 23, 33, 43, 53 ... Curve part (light scattering part) , 24, 34, 44, 54 ... second optical path, 25 ... light source, 26 ... photodetector, 62, 63, 64, 65, 66 ... sensor unit

Claims (7)

A first optical path for transmitting light supplied from a light source;
A light scattering portion for scattering the light transmitted through the first optical path to the outside;
A second optical path for transmitting the light entering from the light scattering portion to a predetermined position;
With
The first optical path, the light scattering portion, and the second optical path are composed of an integral linear material made of a light transmissive material,
The amount of light scattering to the outside in the light scattering portion is larger than the amount of light scattering to the outside in the first optical path or the amount of light scattering to the outside in the second optical path. Object detection sensor.   The liquid substance detection sensor according to claim 1, wherein the first optical path and the second optical path are provided in parallel.   3. The liquid substance detection sensor according to claim 1, wherein surfaces of the first optical path and the second optical path are covered with a light-shielding material. 4.   The liquid substance detection sensor according to claim 1, wherein the light scattering unit has a light transmission direction different from that of the first optical path. A method for detecting the presence of a liquid substance with a sensor,
The sensor is
It is composed of a light transmissive material, and includes a linear first optical path, a curved portion provided continuously with the first optical path, and a linear second optical path provided continuously with the curved portion,
A method for detecting a liquid substance, comprising: monitoring a fluctuation in intensity of light emitted from the second optical path while supplying light having a predetermined intensity to the first optical path.   The liquid substance detection method according to claim 5, wherein a plurality of the sensors are arranged at predetermined intervals, and fluctuations in light intensity in the sensors are monitored. A method of forming a composite material structure of a predetermined shape with a composite material containing reinforcing fibers and resin,
The reinforcing fiber base is covered with an airtight sheet having airtightness in a state where the reinforcing fiber base is placed along the surface of a mold having a shape corresponding to the composite structure, and the outer periphery of the airtight sheet is Sealing hermetically with the mold and forming a molding region;
Depressurizing the molding region in the hermetic sheet;
Injecting resin into the molding region, impregnating the resin into the reinforcing fiber base, and
In the step of impregnating the resin, the impregnation state of the resin is monitored by a plurality of resin detection sensors arranged in the molding region and in the resin impregnation direction,
The resin detection sensor is made of a light transmissive material, and includes a first optical path, a curved portion connected to the first optical path, and a second optical path connected to the curved portion,
A method of forming a composite material structure, wherein the impregnation state of the resin is monitored by fluctuation of the intensity of light emitted from the second optical path while supplying light of a predetermined intensity to the first optical path .

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