JP5460354B2 - Liquid leak detection device - Google Patents

Description

  The present invention relates to a liquid leakage detection apparatus, and more particularly to an apparatus for detecting liquid leakage in a microchemical plant.

  A microchemical plant is a facility for mixing, reacting, and separating substances in a microscale space. In a microchemical plant, a small amount of reagent is reacted quickly, so that precise reaction control is possible.

  Microchemical plants have many advantages compared to mass production plants that are constructed by scaling up manufacturing techniques established at the laboratory stage. For example, since a small amount of reagent is rapidly mixed, reacted, separated, etc., a desired amount of product can be obtained in a short reaction time. In addition, the production technology established at the laboratory stage can be numbered up to easily build mass production equipment. Furthermore, it is easy to adapt to reactions involving explosions, and the safety of the production process is improved. Due to these advantages, research and development on microchemical plants have been actively conducted in recent years.

  By the way, when liquid leakage occurs from the apparatus during the start-up of the microchemical plant, problems such as damage to the microplant and the accuracy of the product occur. Therefore, it is necessary to quickly detect when a liquid leak occurs. Conventionally, the following devices are known as devices for detecting liquid leakage.

  In FIG. 7, the water detection sensor of patent document 1 is shown. The water detection sensor 71 includes a case 72, a bending jig 73, an expansion body 74, a holding jig 75, an optical fiber 76 between the bending jig 73 and the expansion body 74, and an end of the optical fiber 76. A bending loss measuring device 77 is provided in the part.

  In this water detection sensor, when water contacts the expansion body 74 due to liquid leakage, the expansion body 74 expands. Then, the expanded optical body 76 is pressed against the bending jig 73 by the expanded body 74, and local bending occurs in the optical fiber 76. In the local bending portion, the transmitted light leaks and the amount of light transmitted through the optical fiber 76 is lost. As a result, the loss occurrence position and the loss of the light transmission amount are detected by the bending loss measuring device 77, and the liquid leakage is specified.

  FIG. 8 shows an optical fiber leakage detection device of Patent Document 2. The optical fiber sensor leakage detection device includes a laser light source 81, an optical circulator 82, an optical fiber 84, a signal generator 85, an ultrasonic oscillator 86 that generates an ultrasonic wave propagating through the optical fiber, and an optical fiber. A fiber Bragg grating (hereinafter referred to as FBG) 83 for measuring the intensity of propagating ultrasonic waves, a photoelectric converter 87 (for reflected light), a photoelectric converter 88 (for transmitted light), and a data recording device 89 Prepare.

  In this optical fiber leakage detector, laser light from a laser light source 81 is incident on an optical fiber 84 provided with an FBG 83 via an optical circulator 82. The laser light reflected by the FBG 83 is incident on the photoelectric converter 87 (for reflected light), and the laser light transmitted through the FBG 83 is incident on the photoelectric converter 88 (for transmitted light).

  The ultrasonic oscillator 86 receives the ultrasonic excitation signal from the signal generator 85, generates an ultrasonic wave, and propagates the ultrasonic wave to the optical fiber 84. When the liquid comes into contact with the optical fiber 84, a part of the ultrasonic wave leaks from the optical fiber 84 to the liquid at that portion, and the intensity of the ultrasonic wave propagating through the optical fiber 84 is reduced. That is, when the intensity of the ultrasonic wave propagating through the optical fiber 84 is reduced due to liquid leakage, the strain state of the FBG 83 changes, and the intensity of light reflected by the FBG 83 changes.

  FIG. 9 shows a leak sensor of Patent Document 3. The leak sensor main body 91 includes a case 92, a detection point 93, a light projecting unit 94, a light receiving unit 95, a liquid introducing unit 96, and an electric control circuit 97.

  In this liquid leakage sensor, the liquid introduction unit 96 guides the liquid leakage toward the detection point 93 by capillary action. The detection light 98 is emitted from the light projecting unit 94 to the detection point 93. The detection light 98 is reflected by the detection point 93 and received by the light receiving unit 95. Since the refractive index is different between the leaking state and the non-leaking state at the detection point 93, the light amount of the reflected light 99 changes due to the liquid leakage. From the change in the amount of reflected light 99 due to leakage, the electric control circuit 27 detects leakage.

JP 2004-45220 A JP 2007-24798 JP 2006-234388 A

  The microchemical plant is small in scale and uses a small amount of material (solution). Therefore, control of inflow / outflow of a small amount of solution is an important technique. Therefore, the injection of the solution into the microchemical plant is performed by a syringe pump that can accurately control the release of a small amount of solution. In brief, the syringe pump has the same structure as a syringe, and is composed of a cylinder and a piston.

  The cylinder and piston are extremely airtight. For this reason, suction and discharge of a small amount of solution can be accurately performed by position control of the piston. However, care must be taken with respect to cavitation during inhalation and leakage during use in order to accurately inhale and release the solution.

  Cavitation at the time of inhalation generates bubbles in the syringe pump, causing an error between the actual solution suction amount and the control position of the piston. Liquid leakage during use also causes an error between the amount of remaining solution in the syringe pump and the control position of the piston. These will give an error in the amount of solution supplied to the microchemical plant.

  Cavitation during inhalation can be suppressed by slowly moving the piston. However, the liquid leakage during use is caused by factors other than the operation such as deterioration of packing and biting of foreign matter because of airtightness between the cylinder and the piston. Therefore, it is necessary to always monitor the presence or absence of liquid leakage.

  However, in the conventional apparatus related to liquid leakage detection shown in Patent Documents 1 to 3, since the detection unit occupies a large space due to the structure of the apparatus, the amount of liquid leakage of the syringe pump is as small as several microliters to several milliliters. There was a problem that it was not possible to detect liquid leakage. In addition, the liquid leak detection devices of Patent Documents 1 to 3 have a problem that a large space is required for installation and cannot be arranged around a syringe pump of a microchemical plant.

  In view of such problems, an object of the present invention is to provide an optical liquid leakage detection device that can accurately detect even a small amount of liquid leakage and that can be installed in a microchemical plant having a limited installation space.

In order to solve the above problems, the liquid leakage detection device of the present invention is
A liquid leakage detection device that is attached to a syringe pump and detects liquid leakage from the syringe pump,
Holder means fixed to the syringe pump;
An inclined surface connected to the holder means and disposed below the opening end of the cylinder of the syringe pump under gravity;
An edge wall provided around the inclined surface;
A projector and a receiver disposed at the bottom of gravity formed by the inclined surface and the edge wall;
A laser light source for sending a laser beam to the projector;
A measuring device for detecting a change in the amount of light of the light receiver is provided.

  Moreover, the liquid leak detection device of the present invention is characterized in that the opening direction of the opening end is arranged below gravity in the horizontal direction.

  Furthermore, a dropping rod is arranged between the opening end whose opening direction is directed below gravity in the horizontal direction and the inclined surface.

  The liquid leakage detection device of the present invention has the above-described configuration, and can accurately detect even a small amount of liquid leakage of several microliters to several milliliters. Moreover, since the detection part of the liquid leak detection apparatus of this invention is comprised simply and compactly, it can be installed also in the narrow microchemical plant with restrictions in an installation place.

  In particular, if the tray is formed or coated with a material having water repellency, even if a small amount of liquid leaks, the droplets can be efficiently attracted to the detection part of the tray, and the detection sensitivity of the liquid leak can be increased. it can.

  In addition, since an optical sensor is used instead of an electrode sensor, there is no need to worry about electrode corrosion, and it can be handled regardless of the type of liquid used in the microchemical plant. Furthermore, by arranging the opening direction of the opening end of the cylinder downward from the horizontal direction and placing a dripping rod between the opening end and the inclined surface, even if there is even a small amount of liquid leakage, the leaked liquid is placed at the bottom of gravity. Guide and detect leaks.

It is a whole block diagram of a syringe pump. It is a figure which shows the structure of 1st Embodiment of the liquid leak detection apparatus of this invention. It is an enlarged view of the opening end of a syringe pump. It is a figure which shows the cross section of 1st Embodiment. It is a figure of a part of liquid leak detection apparatus concerning a 2nd embodiment of the present invention. It is a partial figure of the liquid leak detection apparatus which concerns on 3rd Embodiment of this invention. It is a liquid leak detection apparatus of a prior art. It is another prior art liquid leak detection apparatus. It is another prior art liquid leak detection apparatus.

(Embodiment 1)
FIG. 1 shows the appearance of the syringe pump 50. The syringe pump 50 includes a cylinder 51, a piston 52, and a controller 59. The cylinder 51 is fixed to a controller 59 by a holder 57, and the controller 59 is provided with a drive unit 58 that slightly displaces the piston 52. A packing 54 is provided at the tip 53 of the piston 52 to ensure fluid tightness with the inner wall of the cylinder 51. The controller 59 moves the drive unit 58 at an input signal or at a predetermined timing, and performs an operation of pushing in or pulling out the piston 52. The cylinder 51 is arbitrarily arranged vertically, horizontally, and obliquely depending on the form used. In the subsequent drawings, the controller 59 is omitted.

  In FIG. 2, the outline of the liquid leak detection apparatus 1 of this invention is shown. The liquid leak detection device 1 according to the present invention includes a holder unit 12 for being arranged in a predetermined positional relationship with the cylinder 51 of the syringe pump 50, and a gravity unit below the opening end 56 of the cylinder 51 by the holder unit 12. An inclined surface 11 that is fixed and disposed obliquely with respect to the vertical line, an edge wall 13 provided around the inclined surface 11, and a gravity bottom formed by the inclined surface 11 and the edge wall 13 The projector 14 and the light receiver 15, a laser light source 16 that transmits light to the projector 14, and a light measuring device 17 that detects a change in the light amount of the light receiver 15 are included.

  The holder means 12 is a portion fixed to the cylinder 51 in order to fix the inclined surface 11 to the opening end 56 of the cylinder 51 below the gravity. In FIG. 2, although it is a shape which has a through-hole which the cylinder 51 penetrates in the middle of a column shape, it is not limited to this.

  The inclined surface 11 is a slope for guiding the solution leaking from the opening end 56 of the cylinder 51 to the photosensitive portion 21 formed by the light projector 14 and the light receiver 15. Therefore, the inclined surface 11 is arranged below the gravity end of the opening end 56 of the cylinder 51. Here, the gravity downward means downward in the direction of gravity. This is to collect the leaked solution. Further, the inclined surface 11 is not limited to a flat surface. For example, it may have a conical inner surface like a funnel.

  The cylinder 51 may penetrate the inclined surface 11. This is because the inclined surface 11 is arranged around the cylinder 51. If resin, a rubber member, or the like is interposed between the periphery of the cylinder 51 and the inclined surface 11 to improve the adhesion, the leaked solution can be efficiently attracted without the liquid leaking from the gap.

  As a resin for improving the adhesion, a vinyl chloride resin, a urethane resin, an epoxy resin, or the like can be used. As the rubber member, nitrile rubber, fluorine rubber, polyurethane rubber, or the like can be used.

  Moreover, it is desirable that the inclined surface 11 is provided with water repellency. This is because even a small amount of leakage from the cylinder 51 rolls down on the inclined surface 11 and reaches the photosensitive portion 21. As the water repellent material, a substance such as a hydrogen fluoride resin (for example, polytetrafluoroethylene), a silicon resin (for example, dimethyl silicon), and HIREC (registered trademark) can be suitably used.

  The edge wall 13 is a wall formed around the inclined surface 11. The solution that has fallen from the opening end 56 of the cylinder 51 is provided so as not to fall from the inclined surface 11. Therefore, in FIG. 2, it is formed in parallel around the cylinder 51, but is not limited to this direction. Further, it may not be formed so as to surround the entire circumference of the inclined surface 11. However, since the liquid leak detection apparatus 1 of the present invention collects and detects the solution leaked from the opening end 56 of the cylinder 51 in the photosensitive portion 21, the edge wall 13 must be formed in the portion where the photosensitive portion 21 is disposed. I must. A portion that is formed by the inclined surface 11 and the edge wall 13 and accumulates the solution rolling down the inclined surface 11 is referred to as a gravity lowermost portion 20.

  A photosensitive portion 21 formed by a projector 14 and a light receiver 15 is disposed at the lowest gravity portion 20 formed by the inclined surface 11 and the edge wall 13. The projector 14 includes a laser light source 16 and an optical fiber 18. Laser light is emitted from the tip of the optical fiber 18. The light receiver 15 is formed of a light measuring device 17 and an optical fiber 19, and the light measuring device 17 detects the intensity of light incident from the tip of the optical fiber 19. A condensing lens may be provided at the tip of the optical fibers 18 and 19.

  In FIG. 2, the laser light source 16 and the optical measuring device 17 are shown as being formed in the same casing, but they may be separate casings. In addition, the control device 25 is also included in the housing. The control device 25 controls the operation of the liquid leak detection device 1.

  The tips of the optical fibers 18 and 19 are fixed in parallel. A portion where the optical fibers are fixed in parallel is referred to as a photosensitive portion 21. Laser light is emitted from the photosensitive unit 21, but since the light receiver side fiber 19 faces the same direction as the laser light emission direction, the laser light does not enter the light measuring device 17 as it is.

  As shown in FIG. 2, the photosensitive portion 21 is disposed toward the gravity lowermost portion 20 formed by the inclined surface 11 and the edge wall 13. Accordingly, the laser light emitted from the projector-side fiber 18 hits the gravity lowermost portion 20, and the reflected light is detected by the receiver-side fiber 19.

  Next, the operation of the liquid leak detection apparatus 1 of the present invention will be described. First, the liquid leak detection device 1 of the present invention is installed in the cylinder 51 as shown in FIG. The photosensitive unit 21 is disposed in the lowest gravity layer 20 and records the intensity of light received by the light receiver 15 in this state. The light intensity at this time becomes the reference intensity. The recording of the reference intensity is obtained by controlling the laser light source 16 and the optical measuring device 17 under the control of the control device 25.

  FIG. 3 shows an enlarged view of the opening end 56 of the cylinder 51. A packing 54 is disposed between the cylinder 51 and the tip 53 of the piston 52 in order to ensure liquid tightness. However, liquid leakage may occur due to deterioration over time or biting of foreign matter. The leaked solution spills 61, 62 from the open end 56 of the cylinder 51 when the piston 52 is pulled up.

  Referring to FIG. 4, spilled solution 61 travels along the side wall of cylinder 51 and reaches inclined surface 11, and travels along inclined surface 11 and reaches gravity bottom 20. When the solution reaches the photosensitive portion 21 arranged at the lowest gravity portion 20, the laser light emitted from the projector 14 is diffusely reflected, and the intensity of the light detected by the light receiver 15 changes. The light intensity at this time is compared with the reference intensity, and when the change is greater than a predetermined threshold, the control device 25 determines that liquid leakage has occurred.

  If it is determined that a liquid leak has occurred, at least a liquid leak occurrence signal 35 is transmitted. The liquid leak occurrence signal 35 may be transmitted to a control device that controls the entire microchemical plant, or may cause a liquid leak warning light 36 or an alarm sound. As described above, according to the liquid leakage detection device 1 of the present invention, a small amount of liquid leakage from the syringe pump 51 can be detected with high accuracy.

(Embodiment 2)
FIG. 5 is a diagram showing a liquid leakage device 2 according to the present embodiment. The projector and receiver were omitted. The point that the photosensitive portion 21 is installed in the lowest gravity portion 20 is the same as that in the first embodiment. In the present embodiment, the cylinder 51 has the liquid injection outlet 55 disposed at the top, and the piston 52 is located below the gravity. In order to achieve the above arrangement, the liquid leakage device 2 of the present embodiment is fixed to the cylinder 51 by the support column 22 and the holder band 23 connected to the inclined surface 11. The support 22 and the holder band 22 are combined to form the holder means 12.

  Further, the cylinder 51 is disposed to be inclined with respect to the vertical direction 7, and the dropping rod 30 is disposed between the inclined surface 11 and the opening end 56 of the cylinder 51. In FIG. 5, the vertical direction is denoted by reference numeral 7 and the horizontal direction is denoted by reference numeral 8. The reason why the cylinder 51 is tilted is to make it easier to collect the solution that falls along the inner wall of the cylinder 51. Further, the dropping rod 30 is intended to facilitate the transfer of the solution from the open end 56 to the inclined surface 11. In the present embodiment, since the opening end 56 of the cylinder 51 is directed downward in the direction of gravity, a smaller amount of leakage can be detected.

(Embodiment 3)
FIG. 6 is a diagram showing a liquid leakage device 3 according to the present embodiment. In the present embodiment, the cylinder 51 is disposed so as to be inclined from the flat direction 8 so that the cylinder opening end 56 is directed downward in the gravity direction. The inclined surface 11 is arranged below the gravity from the opening end 56. In order to maintain such an arrangement relationship, the holder means 12 connected to the inclined surface 11 is attached to the cylinder 51. By orienting the cylinder in the horizontal direction, gravity does not act in the operation direction of the piston, so that the outflow accuracy of the solution is improved.

  The point which arrange | positions the dripping stick | rod 30 in the opening end 56 of the cylinder 51 is the same as Embodiment 2. FIG. Also in this embodiment, the display of the projector and the light receiver is omitted. However, it is arranged at the gravity bottom 20. The liquid leakage detection device 3 of the present invention can be applied even when the cylinder 51 is arranged in the horizontal direction 8.

  The present invention relates to an optical liquid leakage detection apparatus, and in particular, is used for an apparatus for detecting liquid leakage in a microchemical plant.

DESCRIPTION OF SYMBOLS 1 Liquid leak detection apparatus 11 Inclined surface 12 Holder means 13 Edge wall 14 Light projector 15 Light receiver 16 Laser light source 17 Optical measuring device 18 Light projector side optical fiber 19 Light receiver side optical fiber 20 The lowest part of gravity 21 Photosensitive part 22 Strut 23 Band holder 25 Control device 30 Drip bar 35 Liquid leak occurrence signal 36 Leakage warning light 50 Syringe pump 51 Cylinder 52 Piston 53 Piston tip 54 Packing 55 Liquid injection outlet 56 Cylinder opening end 57 Holder 58 Drive unit 59 Controller

Claims (3)

A liquid leakage detection device that is attached to a syringe pump and detects liquid leakage from the syringe pump,
Holder means fixed to the syringe pump;
An inclined surface connected to the holder means and disposed below the opening end of the cylinder of the syringe pump under gravity;
An edge wall provided around the inclined surface;
A projector and a receiver disposed at the bottom of gravity formed by the inclined surface and the edge wall;
A laser light source for sending a laser beam to the projector;
A liquid leakage detection apparatus comprising a measuring device for detecting a change in light quantity of the light receiver.   The liquid leakage detection device according to claim 1, wherein an opening direction of the opening end is arranged below a horizontal direction of gravity.   The liquid leakage detection device according to claim 2, further comprising a dropping rod between the opening end and the inclined surface.