JPH0124618Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to a liquid detector used for detecting leaked liquid.

(Technical background of the invention and its problems) When condensation occurs in a narrow space such as inside a container or pipe, water droplets accumulate there. If this container contains a substance that dislikes water, it is necessary to detect even the slightest amount of water and take appropriate measures.
The same applies to piping. In addition, minute cracks or pinholes may occur in the seams of oil or chemical containers that cannot be allowed to leak, resulting in liquid leakage.
Even such a small amount of leakage can lead to a major accident, so a highly reliable detector is required.

(Purpose of the invention) The invention was made with the above points in mind.
It is an object of the present invention to provide a detector suitable for detecting a small amount of leaked liquid.

(Summary of the invention) The invention consists of a liquid detection section formed by fusing the tips of two optical fibers, a tip fitting that houses the liquid detection section, and a cap that can be attached to the tip fitting. and a liquid-absorbing member that is inserted between the tip metal fitting and the cap, contacts the liquid detection section within the protective case, and has an exposed portion outside the protective case. The present invention relates to a characteristic liquid detector.

(Embodiment of the invention) The detection part of the liquid detector of the invention is, for example,
-Use the one described in Publication No. 39316.

In other words, as shown in FIG.
was formed. As can be seen from the cross section, the spherical part 2 is covered on the outside with the cladding 3 of the optical fiber 1, and the spherical part 2 is covered with a cladding 3 of the optical fiber 1.
The light incident on the optical fiber follows the path shown by arrows 4 and 5 and is sent to the other optical fiber. If water droplets or the like adhere to the outer surface of the spherical part, the light passing through the spherical part 2 along the path indicated by the arrow 5 cannot be totally reflected, and a considerable portion of the light will leak. This changes the amount of light that returns to the optical fiber from the spherical portion 2, making it possible to detect the presence or absence of liquid.

Such a detection section has the advantage that even a small amount of liquid can be detected with high sensitivity because the spherical section can be made extremely small to the same size as the outer diameter of an optical fiber.

2 and 3 are assembled perspective views of the liquid detector of the present invention.

In the figure, two optical fibers 1 are housed through a cushioning plastic tube 7 in a metal tube 6 whose outer periphery is corrugated in a spiral manner. The tip of the optical fiber 1 is fused to form a detection section 8 as shown in FIG. The tip fitting 9 has a through hole 10 at its right end through which the detection section 8 is inserted, and an opening 11 into which one end of the metal tube 6 is inserted at its left end.

Further, around the through hole 10, there is provided a threaded pin 13 on the outer periphery of which a cap 12, which will be described later, is screwed.
Three trees have been planted.

The end of the optical fiber is housed in a protective glass tube 14, leaving the detection section 8 at its tip, and is fixed with adhesive using epoxy resin or the like. Thereafter, the tip end fitting 9 is adhesively fixed to the metal tube 6 with epoxy or the like so that the tip of the detection part 8 protrudes into the through hole 10 of the tip fitting 9.

Next, as shown in FIG.
is set so that the detection part 8 fits into the through hole 17 in its center, and finally the cap 12 is screwed in. The respective positional relationships are shown in the partial longitudinal sectional view of FIG. 4, and the completed drawing is shown in FIG. The same parts as those in each of the figures described above are designated by the same reference numerals, and the explanation thereof will be omitted.
In the completed state, the detection part is in contact with the water-absorbing paper.

Such a liquid detector is supported and fixed so that the water-absorbing paper 16 is in contact with the inner wall of the pipe. When a small amount of moisture condensed on the inner wall of the pipe is absorbed by the absorbent paper, the detection unit detects this.

According to experiments, the detector was activated when water droplets of 0.2 cc were absorbed using absorbent paper with an outer diameter of 8 mm and a thickness of 0.1 mm. At this time, the outer diameter of the detection part was approximately 250 microns, and the diameter of the optical fiber was approximately 100 microns.

Nonwoven fabric, cloth, etc. may be used instead of the above-mentioned water-absorbing paper.

Further, any so-called liquid-absorbing material such as a foamed molded product or powder having open cells may be used. By selecting this liquid-absorbing member, the shape of the cap can be changed as appropriate. If a liquid-absorbing string is used, a through hole may be provided in the cap to allow the tip of the string to come out. The amount of liquid that can be detected can also be adjusted by changing the volume of the liquid absorbing member.

In addition, since the liquid-absorbing member can be replaced as appropriate,
If it is removed after use and the liquid absorbed by the liquid absorbent member is removed by a method such as vaporization, it can be used again, and of course it is also possible to use a new liquid absorbent member.

(Effects of the invention) The liquid detector of the invention described above has the following effects.

Since the liquid to be detected is absorbed by the liquid-absorbing member and the presence or absence of the liquid is detected by the detection part in contact with the liquid, a trace amount of liquid can be detected with high sensitivity.

Since the liquid to be detected is held in the detection section, the detection output is stable and there are fewer malfunctions.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of an embodiment of the detection section of the detector of the present invention, Figs. 2 and 3 are assembly diagrams of the embodiment of the detector of the present invention, Fig. 4 is a partial vertical sectional view thereof, and Fig. 5
The figure is a perspective view of the completed state. DESCRIPTION OF SYMBOLS 1... Optical fiber, 8... Detection part, 16... Liquid absorbing member.

Claims (1)

[Scope of utility model registration request] A protective case consisting of a liquid detection section formed by fusing the tips of two optical fibers, a tip fitting housing the liquid detection section, and a cap attachable to the tip fitting, and the tip fitting and the cap. and a liquid-absorbing member inserted between the protective case and the liquid-absorbing member that contacts the liquid detection portion within the protective case and has an exposed portion outside the protective case.