JP3469537B2 - Liquid leak sensor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak sensor for detecting leaks leaking from containers, pipes and the like.

[0002]

2. Description of the Related Art As a conventional example 1 of this type of leak sensor,
For example, as disclosed in Japanese Examined Patent Publication No. 4-70572, as shown in FIG. 16, a light-transmitting wall 5A standing upright with respect to the surface F to be submerged and a black non-light-transmitting wall 5B are provided. The white thin paper 6 is sandwiched, one end of the thin paper 6 is hung down on the surface F to be submerged, and the translucent wall 5 faces the light projecting / receiving sections 3 and 4. Then, when there is no liquid leakage L, the light emitted from the light projecting unit 3 is diffused and reflected by the white thin paper 6, and the diffuse reflection light is received by the light receiving unit 4, and when there is liquid leakage L, it is white. The thin paper 6 becomes wet and becomes transparent, and as a result, the light emitted from the light projecting unit 3 is applied to the black non-translucent wall 5B, and the diffuse reflected light is received by the light receiving unit 4. That is,
In this device, the liquid leakage L is detected based on the difference in the amount of light received by the light receiving unit 4 due to the change in color of the reflection portion.

Further, as a second conventional example, the above-mentioned publication discloses a structure in which the irregular reflection surfaces of two ground glass pieces are opposed to each other without using thin paper. In this product, normally, white ground glass becomes transparent when it gets wet.Like the one described above, liquid leakage is detected based on the difference in the amount of light received by the light receiving part due to the change in color of the reflective part. To do.

[0004]

However, in the liquid leakage sensor of Conventional Example 1, after detecting the liquid leakage, the thin paper must be replaced as a consumable item at the time of maintenance work for wiping the liquid leakage, and the used thin paper is used. Need to be disposed of as garbage.

Further, in the liquid leakage sensor of the conventional example 2, it is difficult to wipe off the liquid leakage from the ground glass, and it is not enough to wipe the liquid out of the ground glass to the original white state. You will need it. Further, in the case of oily liquid, there arises a problem that the mucus must be washed off with a special chemical.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a leak sensor capable of detecting even a slight leak and facilitating maintenance work. .

[0007]

In order to achieve the above object, in a liquid leakage sensor according to the invention of claim 1, a pair of translucent members are assembled and a slit is formed between the translucent members. When the inner surface of the slit is a detection surface that can be submerged in liquid leakage, the light projection unit that obliquely irradiates light from the inside of the translucent member toward the detection surface, and the detection surface, when the liquid is not submerged in liquid leakage , A light receiving unit for receiving the light emitted from the light emitting unit and reflected by the detecting surface, the detecting surface having a smooth surface structure, and when the detecting surface is submerged in the liquid leakage, The light is transmitted through the detection surface, and the amount of light received by the light receiving unit changes, so that liquid leakage is detected.

According to a second aspect of the present invention, in the liquid leakage sensor according to the first aspect, one light transmitting member is provided with a tapered portion which is tapered toward the other light transmitting member, and the other light transmitting member is provided. The light member has a receiving space for receiving the tapered portion and gradually narrowing toward the back side. The light transmissive members are in contact with each other to form a slit between the light transmissive members. The feature is that the contact portion is provided.

The invention of claim 3 relates to claim 1 or claim 2.
In the liquid leakage sensor described above, the slit is characterized in that the slit is inclined with respect to the arranged surface on which the liquid leakage sensor is arranged.

[0010]

<Invention of Claim 1><Invention of Claim 1> According to the configuration of Claim 1, when the liquid leakage reaches one end of a narrow space such as a slit, it is drawn into the space (slit). Submerge in. Further, since the detection surface is arranged in this slit, even a slight leak can be drawn to the detection surface side, and the leak can be detected immediately. Also,
After the liquid leakage is detected, during the maintenance work for wiping the liquid leakage, by disassembling both translucent members, the detection surface is exposed and the liquid leakage can be easily wiped from the detection surface. Moreover, in the present invention, since the detection surface has a smooth surface structure, the wiping operation is easier than the conventional one using ground glass, and since thin paper is not required, there is no dust.

<Invention of Claim 2> When the tapered portion of one light transmitting member is inserted into the deep part of the receiving space provided in the other light transmitting member, the abutting portion abuts between both light transmitting members, A slit is formed between the both translucent members. Here, since one of the translucent members has a tapered shape, a sufficient gap is ensured between the tapered portion of the one translucent member and the peripheral wall of the receiving space until reaching the inner part of the receiving space. The insertion / removal work can be performed smoothly.

<Invention of Claim 3> According to the configuration of Claim 3, since the slit is oblique to the surface to be arranged, the slit is oriented vertically like the conventional one. Compared with this, it is possible to draw the leaked liquid toward the detection surface side earlier, and it is possible to detect the leaked liquid even more quickly. Moreover, since the detection surface inside the slit is also formed obliquely with respect to the arranged surface, the light transmitted through the detection surface obliquely strikes the arranged surface and the side wall standing upright from the arranged surface, The liquid is reflected in the direction away from the detection surface, and stable liquid leak detection is possible without being affected by the reflected light.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION <First Embodiment> A liquid leakage sensor according to a first embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral F is a submerged surface (corresponding to the “arranged surface” of the present invention) that can be submerged in liquid leakage, for example, a pan (container provided below the tank for liquid storage). ) Bottom surface. Further, this pan is made of, for example, stainless steel. Therefore, the water-immersed surface F of this embodiment has a mirror surface shape and reflects the received light.

The housing 10 provided in the liquid leakage sensor of the present embodiment comprises a main body housing 11 and a receiving housing 30.
And assembled. The main body housing 11 has a shape in which a truncated cone is connected to the lower end of a cylindrical body as a whole, and an outer wall other than the upper surface thereof serves as a light transmitting member 12 (corresponding to "one light transmitting member" of the present invention). Is configured. More specifically, the translucent member 12 is formed by connecting a tapered tapered wall 14 to the lower end of the cylindrical wall 13, and closing the lower end surface of the tapered wall 14 with a bottom wall 17. The holding bracket 20 is housed inside the transparent member 12, and the upper surface of the transparent member 12 is closed by a disc 21.

Optical fibers 50F and 51F for projecting light and receiving light are penetrated through the central portion of the disk 21, and the tip portions of these optical fibers 50F and 51F are inside the tapered wall 14 as shown in FIG. It is matched to the circumference.
More specifically, a pair of ridges 15, 15 extend side by side in the vertical direction on the inner peripheral surface of the tapered wall 14 (in FIG. 1 and FIG. 2, only one ridge 15 is provided). Is represented.
(See FIG. 3). As shown in FIG. 3, each of the protrusions 15 has side surfaces 15A and 15B that are obliquely raised from the inner peripheral surface of the tapered wall 14 when viewed in a horizontal cross section of the light transmissive member 12, and has a receiving surface 15C at the tip. It is formed, and the holding bracket 20 is pressed against it.

As shown in FIG. 3, grooves 14A, 14A are formed on both sides of the tapered wall 14 sandwiching both ridges 15, 15 to form grooves 14A, 14A. The tips of the optical fibers 50F and 51F are housed. Then, the tip end surfaces of both the optical fibers 50F and 51F are joined to the side surfaces 15A of the ridges 15 and 15, and are fixed in this state by the holding bracket 20. As a result, both optical axes extending from the tip surfaces of both optical fibers 50F and 51F are positioned so as to intersect at a predetermined position on the detection surface 19 which is the outer surface of the tapered wall 14. Further, in the present embodiment, the tip of the optical fiber for projection 50F shown on the upper side in FIG. 3 constitutes the light projecting section 50 according to the present invention, and the tip of the optical fiber for reception 51F shown on the lower side is the It constitutes the light receiving portion 51 according to the invention. Further, the detection surface 19, which is the outer surface of the tapered wall 14, has a smooth surface structure so that even if a leaked liquid adheres, it can be easily wiped off.

On the other hand, the receiving housing 30 (corresponding to "the other translucent member" of the present invention) is made of, for example, a translucent member, and has an annular shape as a whole as shown in FIG. Inside the surrounded peripheral wall 31, the receiving space 3 opened up and down
It is equipped with 2. The inner surface of the peripheral wall 31 is inclined like a mortar so that the receiving space 32 gradually narrows downward. Further, on the upper edge of the peripheral wall 31, contact portions 33 are formed at positions where the peripheral wall 31 is equally arranged in the circumferential direction. The contact portion 33 slightly protrudes from the inner peripheral surface of the peripheral wall 31, and the upper surface 33A thereof has, for example, the translucent member 12 described above.
Corresponding to the tapered wall 14 of FIG. Further, on the lower end surface of the peripheral wall 31, communication holes 34 for communicating the peripheral wall 31 with the inside and outside are provided at a plurality of positions in the circumferential direction.

The electrical structure of the leak sensor is as follows. That is, a light projecting element is arranged opposite to the base end side of the light projecting optical fiber 50F, and the light emitted by being driven by the light projecting circuit is emitted from the light projecting optical fiber 5F.
The light is emitted from the light projecting unit 50 on the front end side of 0F. On the other hand, a light receiving element is arranged on the base end side of the light receiving optical fiber 51F so as to face it, and the light received by the light receiving section 51 on the tip side of the light receiving optical fiber 51F is given to the light receiving element, and accordingly the light receiving element. A light receiving signal is output from the light receiving circuit connected to. When the light receiving circuit outputs a light receiving signal according to the amount of light received by the light receiving element, this is given to the comparison circuit. In the comparison circuit, the light from the light projecting unit 50 causes the detection surface 1 due to liquid leakage.
A reference level corresponding to the intensity of the light received by the light receiving section 51 when the light passes through 9 is set. Then, the comparison circuit compares the reference level with the reception signal output from the light receiving circuit.

The operation and effect of the liquid leakage sensor of the present embodiment having the above structure will be described. To install the leak sensor,
The lower end of the main body housing 11 may be inserted into the receiving space 32 of the receiving housing 30. At this time, since the lower end of the main body housing 11 is tapered, the receiving space 32
A sufficient gap is secured between the lower end of the main body housing 11 and the peripheral wall 31 of the receiving space 32 until the inner part of the main body housing 11, and the main body housing 11 can be inserted and removed smoothly.

The lower end of the main body housing 11 is
When inserted into the receiving space 32, the bottom wall 17 of the main body housing 11 abuts on the submerged surface F and the abutting portion 3
3 hits the tapered wall 14 of the main body housing 11,
The lower end of the main body housing 11 and the peripheral wall 31 of the receiving space 32
A slit S1 (see FIG. 1 and FIG. 3) is formed between and. Here, since the lower end portion of the main body housing 11 has a tapered shape corresponding to the peripheral wall 31 of the receiving space 32, as described above, the slit S1 formed between the both ends is, as shown in FIG. It is formed in a state of penetrating the housing 10 in an oblique direction with respect to the flooded surface F.

When the liquid leakage sensor is activated, when there is no liquid leakage, the light from the light projecting section 50 is specularly reflected by the detection surface 19 located in the slit S1, and the specularly reflected light is received by the light receiving section 51. It At this time, the light receiving unit 51 is directly connected to the light projecting unit 50.
The light that has traveled to
When passing through the side surface 15B facing the space 15D (see FIG. 3), the light is refracted and goes to a portion different from the light receiving portion 51. As a result, it is possible to prevent light from being received by the light receiving section 51 on an irregular optical path, and it is possible to improve the S / N ratio.

Now, as shown in FIG. 1, when the liquid leakage L is generated and comes into contact with the outer peripheral surface of the receiving housing 30, the liquid leakage L is formed in the communication hole 34 formed in the receiving housing 30.
The inside of the receiving housing 30 is flooded with water through the slit S1 between the receiving housing 30 and the main body housing 11.
It is drawn in as if it soaks in and spreads thinly. Then, when the leaked liquid L reaches the irradiation point of the light from the light projecting section 50 on the detection surface 19, the light from the light projecting section 50 passes through the detection surface 19 and the receiving housing 30 ahead of it also. The light is transmitted and radiated to the outside of the housing 10.

Here, since the slit S1 is formed obliquely with respect to the surface F to be submerged, it is easier to draw the leaked liquid L, as compared with a slit formed perpendicularly to the surface F to be submerged. The leak L reaches the detection surface 19 earlier. As a result, even a slight leak L can be detected immediately. Moreover, since the detection surface 19 inside the slit S1 is also formed obliquely with respect to the submerged surface F,
The light transmitted through the detection surface 19 strikes the surface F to be immersed obliquely and is reflected in a direction away from the detection surface 19. In addition, even if the side wall W of the pan (container) standing upright from the surface to be submerged F is adjacent to the housing 10, the light emitted to the outside of the housing 10 is obliquely directed to the side wall W,
It is not affected by the reflected light from the side wall W of the pan.
As a result, compared with the case where there is no leak L,
The light receiving intensity of the light receiving section 51 is much smaller, and stable leak detection is possible. Then, the light receiving signal output from the light receiving circuit falls below the reference level, and this is discriminated by the discriminating circuit to detect the occurrence of the liquid leakage L.

After the liquid leakage is detected, the housing 10 may be disassembled into the main body housing 11 and the receiving housing 30 for maintenance work for wiping the liquid leakage. Then, the detection surface 19 is exposed and the leak L can be easily wiped from the detection surface 19. Moreover, unlike the conventional one, no frosted glass is used, so that the wiping operation is easy, and since thin paper is not required, there is no dust.

As described above, according to the liquid leakage sensor of this embodiment, the maintenance work after the liquid leakage is detected can be easily performed. Further, since the detection surface 19 disposed inside the slit S1 and the slit S1 is inclined with respect to the submerged surface F, stable liquid leakage detection is not affected by the submerged surface F and the side wall W of the container. Is possible. Further, since the slit S1 is formed obliquely, the leaked liquid reaches the detection surface 19 earlier than the slit oriented in the vertical direction, and even a slight leak can be detected.

<Second Embodiment> The present embodiment is shown in FIG. 4, and among the receiving housings 30 described in the first embodiment, the receiving housings 30 are arranged at positions such that the receiving housings 30 are equally arranged. The projecting heights of the three contact portions 33 are different as follows. That is, among the four contact portions 33, the contact portion 33D shown on the right side in FIG. 4 is the highest, and the contact portion 33B arranged at a position facing the contact portion 33D is the lowest, and further, The remaining contact portion 33C is the contact portion 33D.
And the contact portion 33B has an intermediate height. Also, 4
The four communication holes 34 provided corresponding to the one contact portion 33 are
The communication hole 34D corresponding to the highest contact portion 33D is the largest and the communication hole 34B corresponding to the lowest contact portion 33B.
Is set to the smallest, and the remaining communication hole 34C
However, it has an intermediate size between the communication hole 34D and the communication hole 34B.

As a result, a slit having a gradually changing size is formed between the main body housing 11 and the receiving housing 30 in the circumferential direction of the receiving housing 30 so as to accommodate liquids having different viscosities. Will be able to.

<Third Embodiment> The liquid leakage sensor of this embodiment is shown in FIGS. 5 and 6, and a housing 60 provided in the liquid leakage sensor includes a main body housing 61 and a sub-housing 70. It will be assembled. Body housing 61
The holding bracket 63 having the same function as the holding bracket 20 of the first embodiment is housed inside the housing-shaped light transmitting member 62, and the upper surface of the light transmitting member 62 is disc 6
It becomes blocked at 4.

At the lower end of the translucent member 62, a receiving portion 65 is formed by denting a corner extending in the horizontal direction (direction normal to the paper surface of FIG. 5, left-right direction of FIG. 6) inward. There is. More specifically, the receiving portion 65, as shown in FIG.
A taper wall 68 hangs obliquely from a tip of a shelf wall 66 protruding from one side wall of the light transmissive member 62 toward the other side wall toward a bottom wall 67 of the light transmissive member 62, and further, an edge of the shelf wall 66. An enclosure wall 69 hangs downward from the section.
The upper end portion of the sub-housing 70 is housed in the space surrounded by 9 and the tapered wall 68.

As shown in FIG. 5, the upper end of the sub-housing 70 has a tapered shape so as to come into close contact with the shelf wall 66, the surrounding wall 69 and the taper wall 68. Further, as shown in FIG. 6, the upper end portion of the sub-housing 70 is also tapered upward at both end portions in the horizontal direction,
Correspondingly, the inner surfaces of the portions of the surrounding wall 69 located at both ends of the translucent member 62 in the horizontal direction are tapered.

Further, as shown in FIG. 5, the auxiliary housing 7
Of the 0, the taper surface 70T facing the taper wall 68 of the translucent member 62 is lower than the upper end side by one step, and as a result, as shown in FIG.
A slit S1 is formed between the slit S1 and the taper wall 68 of the translucent member 62, and the outer surface of the taper wall 68 located inside the slit S1 is used as the detection surface 19 to detect liquid leakage.

The other structure is the same as that of the first embodiment. Even with such a configuration, it is possible to obtain the same effect as that of the first embodiment.

<Fourth Embodiment> The liquid leakage sensor of this embodiment is shown in FIGS. 7 to 9, and is a modification of the liquid leakage sensor of the third embodiment. Hereinafter, the same configurations as those of the third embodiment will be denoted by the same reference numerals, redundant description will be omitted, and only different configurations will be described.

In the translucent member 62W of this embodiment, the shelf wall 6 is
A vertical 68W hangs downward from 6 toward the bottom wall 67, and the upper end of the sub-housing 70W is housed in a space surrounded by the vertical wall 68W and the surrounding wall 69 on all sides.

The upper end portion of the sub-housing 70W has a cross-sectional shape which is orthogonal to the longitudinal direction (left-right direction in FIG. 7).
As shown in FIG. 9, only both ends in the longitudinal direction of the shelf wall 66,
As shown in FIG. 8, the horizontal middle portion extends vertically with the same size so as to be in close contact with the surrounding wall 69 and the vertical wall 68W.

A slit S1 is formed between the intermediate portion in the longitudinal direction of the sub-housing 70W and the vertical wall 68W of the translucent member 62, and the outer surface of the vertical wall 68W located in the slit S1 is used as the detection surface 19. Detect leaks.

<Fifth Embodiment> This embodiment is shown in FIG. 10, and a main body housing 81 provided in a housing 80 of this liquid leakage sensor has a bottom wall 83 of a cylindrical transparent member 82, By bulging upward in the shape of a truncated cone, a truncated cone-shaped space is formed on the lower surface of the translucent member 82, and a truncated cone-shaped auxiliary housing 90 is accommodated in the space. An abutting portion 93 is formed at the upper end of the tapered surface 90T that forms the peripheral surface of the sub housing 90.
A slit S1 is formed between the tapered wall 88 and the sub-housing 90 by abutting against the tapered wall 88 provided on the raised portion of the translucent member 82, and the outer surface of the tapered wall 88 located inside the slit S1 is a detection surface. A leak is detected as 19. Other configurations are the same as those in the first embodiment, and the portions having the same configurations are denoted by the same reference numerals as those in the first embodiment in FIG. 10.

<Sixth Embodiment> This embodiment is shown in FIG. 11 and is a modified example of the fifth embodiment, in which the flat plate portion 94 is located from the lower end of the truncated cone-shaped auxiliary housing 90. The flat plate portion 94 is formed so as to project toward the transparent member 82.
Is configured to face the bottom wall 83 through the slit S1. Further, the truncated cone-shaped portion of the sub-housing 90 does not have the contact portion 93 unlike the fifth embodiment,
The tapered wall 88 of the translucent member 82 and the tapered surface 90T of the sub housing 90 are in surface contact with each other. Further, in the present embodiment, the outer surface of the bottom wall 83 located in the slit S1 is set as the detection surface 19, and the optical axes of the light emitting / receiving sections 50 and 51 are set to intersect with each other on the detection surface 19.

<Other Embodiments> The present invention is not limited to the above-mentioned embodiments, and for example, the embodiments described below are also included in the technical scope of the present invention.
Other than the following, various modifications can be made without departing from the scope of the invention.

(1) In the above embodiment, the slit S1
1 extends linearly as seen in a vertical cross section of the housing 10 as shown in FIG.
When viewed in a vertical cross section of 0, the structure may be curved and extended in a curved shape such as a circle or a parabola.

(2) In the above embodiment, the slit S1
Was formed in a ring shape along the circumferential direction of the housing 10, but the slit may not be formed in a ring shape.
Of 0, for example, a slit may be formed only at a position facing the light emitting / receiving units 50 and 51.

(3) In the above embodiment, the detection surface 19 and the peripheral wall 31 of the receiving space 32 are parallel to each other, but they do not necessarily have to be parallel, and for example, the detection surface 19 and the peripheral wall 31 may face upward. The configuration may be such that the interval between and becomes narrow.

(4) In the first embodiment, the contact portion 33
Was formed on the receiving housing 30 side, it may be formed on the main body housing 11 side.

(5) As shown in FIG. 12, only the detection surface 19 of the main body housing 11 having the same basic structure as that of the first embodiment, which is opposed to the light projecting / receiving sections 50 and 51, is placed on the surface F to be submerged. In addition to standing upright vertically, the inner surface of a part of the peripheral wall 31 of the receiving housing 30 may stand upright with respect to the submerged surface F correspondingly.

(6) As shown in FIG. 13, in the receiving housing 30 having the same basic structure as the first embodiment, the contact portion 33V is continuously extended from the upper end to the lower end of the receiving housing 30. May be

(7) Instead of the receiving housing 30 in the first embodiment, the following receiving housing shown in FIGS. 14 and 15 may be used. That is, the peripheral wall 31V of the receiving housing is configured to have a uniform thickness, and the peripheral wall 3V
Abutting portions 33, 33 are formed at the upper end and the lower end at positions where 5V of the circumferential direction of 1V are evenly arranged, and communication holes 34 are provided at positions where the bottom wall 17 of the receiving housing is equally arranged. You may arrange.

[Brief description of drawings]

FIG. 1 is a side sectional view of a liquid leakage sensor according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of the liquid leakage sensor in a disassembled state.

FIG. 3 is a horizontal sectional view of the leak sensor.

FIG. 4 is a side sectional view of the liquid leakage sensor of the second embodiment in a disassembled state.

FIG. 5 is a side sectional view of a leak sensor according to a third embodiment.

[Figure 6] Front view

FIG. 7 is a front view of a liquid leakage sensor according to a fourth embodiment.

8 is a side sectional view taken along the line AA in FIG.

9 is a partial side sectional view taken along the line BB of FIG.

FIG. 10 is a side sectional view of a liquid leakage sensor according to a fifth embodiment.

FIG. 11 is a side sectional view of a liquid leakage sensor according to a sixth embodiment.

FIG. 12 is a side view showing a state in which the liquid leakage sensor of Modification 1 is disassembled.

FIG. 13 is a side sectional view of a receiving housing according to a second modification.

FIG. 14 is a plan view of a receiving housing according to modification 3;

FIG. 15 is a side sectional view of the receiving housing.

FIG. 16 is a side sectional view of a conventional leak sensor.

[Explanation of symbols]

10, 60, 80 ... Housing 11, 61, 81 ... Main body housing 12, 62, 62W, 82 ... Translucent member 14, 68, 88 ... Tapered wall 19 ... Detection surface 30 ... Receiving housing 32 ... Receptive space 33, 33B, 33C, 33D, 33V ... Contact part 50 ... Projector 51 ... Light receiving part 70, 70W, 90 ... Sub housing 94 ... Flat plate F ... Submerged surface S1 ... slit

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields investigated (Int.Cl. ⁷ , DB name) G01M 3/38 G01V 9/00-9/04 PATOLIS

Claims (3)

(57) [Claims] 1. A pair of translucent members are assembled, a slit is formed between the translucent members, and an inner surface of the slit is used as a detection surface that can be submerged in a leaked liquid from the inside of the translucent member. A light projecting unit that irradiates light obliquely toward the detection surface, and the detection surface that receives light emitted from the light projecting unit and reflected by the detection surface when the detection surface is not submerged in liquid leakage. A light receiving section, wherein the detection surface has a smooth surface structure, and when the detection surface is submerged in liquid leakage, the light from the light projecting section transmits through the detection surface and the light receiving section. A leak sensor, which detects leaks based on a change in the amount of received light. 2. A translucent member on one side is provided with a tapered portion that is tapered toward the translucent member on the other side,
A receiving space that receives the tapered portion and gradually narrows toward the inner side is formed in the other translucent member, and the translucent members are in contact with each other so that a space between the translucent members is formed. The leak sensor according to claim 1, further comprising an abutting portion for forming the slit. 3. The leak sensor according to claim 1 or 2, wherein the slit is oblique to an arrangement surface on which the leak sensor is arranged.