JPH01308935A - Leak inspection apparatus - Google Patents

Abstract

PURPOSE:To easily and visually confirm a fine air bubble by the naked eye and to enhance the reliability of inspection by providing a magnifying glass for magnifying the vicinity of the opening of a ventilation nozzle from the outer peripheral part of a liquid filled container to visually confirm the same. CONSTITUTION:When gas is guided to a ventilation nozzle 10 with the leakage of the gas from an object to be inspected, the liquid in the nozzle 10 receives the pressure of the gas to be downwardly pressed and moved and extruded into a liquid filled container 13 at last to be discharged from the opening end of the nozzle 10to be emitted into the liquid in the container 13 as gas bubbles. These gas bubbles are magnified by a magnifying glass 25 to be visually confirmed. Therefore, by making the diameter of the nozzle 10 fine in order to enhance leak detection accuracy, even when a fine gas bubble is generated, it can be observed easily and visually by the naked eye.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a leak testing device for detecting leakage of pressurized gas supplied to a hollow container or the like in order to test the airtightness of the container or the like.

(Conventional technology) Conventionally, as a leak inspection method for hollow containers such as automobile gasoline tanks, gas is supplied under pressure into the hollow container, and leakage from pinholes or welding defects that occur on the wall of the hollow container is detected. Leak detection devices are used to detect leakage using various leak detector devices such as flowmeters, pressure gauges, and bubble generators for the supply gas, or by immersing a container in a water tank and visually detecting leakage bubbles. .

Among such leak inspection devices, a bubble generator is installed in a liquid-filled container made of a transparent material and in a discharge system for leak gas directly leaking from an object to be inspected, or in a supply path for introducing gas into an object to be inspected. A ventilating nozzle,
a nozzle with its open end disposed in the liquid within the container;
There is a known device which inspects whether there is a leak by visually checking from the outside of the container whether bubbles are generated from the opening end of the ventilation nozzle.

<Problems to be Solved by the Invention> By the way, in such conventional leak inspection devices, the diameter of the ventilation nozzle is made as small as possible to quickly generate air bubbles in response to minute leaks, thereby preventing leaks. Efforts are being made to increase detection accuracy and speed.

However, if the diameter of the ventilation nozzle is made smaller in this way, the air bubbles will become much smaller, making it difficult to see them with the naked eye, which poses the problem of lowering the reliability of leak testing. was there.

In view of the above-mentioned conventional problems, the present invention makes it easier to visually recognize air bubbles discharged into a liquid filling container from above and below the liquid level in a ventilation nozzle and from an opening, thereby improving the reliability of leak inspection. The purpose of the present invention is to provide a leak detection device with improved performance.

(Means for Solving the Problems) For this reason, the leak inspection device of the present invention has the following features: A leak testing device installed in a ventilation nozzle provided so that the liquid level in the pipe is located at a predetermined height from the opening end; and a ventilation nozzle arranged in opposition to the outer surface of the transparent peripheral wall of the container so that the vicinity of the opening end of the ventilation nozzle can be seen through. and a magnifying glass, which enables visual detection of fluctuations in the liquid level within the nozzle and/or air bubbles discharged from the nozzle.

<Function> In this configuration, the liquid in the container enters and rises from the open end immersed in the liquid to a predetermined height position into the pipe of the ventilation nozzle, and as gas leaks from the object to be inspected, the ventilation nozzle When the gas is introduced into the nozzle, the liquid in this nozzle is forced downward under the pressure of the gas, and is finally pushed into the container, and the gas is discharged from the open end of the nozzle, creating bubbles in the liquid in the container. It will be discharged.

This bubble is magnified and visually recognized using a magnifying glass.

Therefore, by reducing the diameter of the ventilation nozzle in order to improve leak detection accuracy, even if microbubbles are generated, they can be easily recognized with the naked eye. In addition, fluctuations in the liquid level within the nozzle can be easily observed even before bubbles are generated.

<Example) Next, embodiments of the present invention will be described based on the drawings.

FIG. 2 shows a schematic circuit configuration of a leak testing system to which an embodiment of the leak testing device according to the present invention is applied.

That is, in the figure, 1 is a hollow container as an object to be inspected, 2
3 is a pressurized gas supply source for supplying test gas under pressure into the hollow container L, 3 is a passage connected to the discharge port of the pressurized gas supply source 2, and 4.5 is a branch from the passage 3. The two branch passages 6 are formed by merging the branch passages 4 and 5 into the hollow container 1.
7 is an air regulating valve installed in the passage 3; 8 is an electromagnetic opening/closing valve installed in the passage 4; 9 is an airtight container installed in an appropriate position in the passage 5. The lower space is a liquid filling container 13 which will be described later.
Consisted of. The passage 5 is divided in the middle, and a transparent ventilation nozzle 10 that opens when immersed in the liquid in the sealed container 9 is connected to the divided passage 5a, and the liquid in the sealed container 9 is connected to the divided passage 5b. Gas discharge passages 11 opening on the surface are connected to each other.

Next, the specific configuration of the leak testing device of this embodiment will be explained based on FIG. 1.

In the figure, 12 is a main body casing in which a leak testing device is disposed, and 13 is a liquid-filled container made of a transparent material, which is attached to the casing 13 via a mounting member 14.

The liquid filling container 13 is formed into a cylindrical shape with a bottom, and has a flange portion 13a around the upper end. This flange part 1
3a is a recess 14 formed on the bottom surface of the mounting member 14;
A is fixed by a fixing plate 16 via screws 15 in a state where it is fitted into a. Reference numeral 17 indicates a contact portion between the inner surface of the recess 14a and the flange portion 13a, and a contact portion between the flange portion 13a and the fixing plate member 1.
These are O-rings for sealing that are interposed at the contact portions with 6.

A hole 18 that extends upward and is closed is formed in the center of the inner surface of the recess 14a, and a pipe portion 19 that extends downward is integrally formed on the closed end surface of the hole 18. The lower end opening of this pipe portion 19 faces a position above the liquid level of the liquid filling container 13, and the opening end of the pipe portion 19 faces the liquid filling container 13.
A ventilation nozzle 10 whose tip end is immersed in a liquid is connected and fixed.

Note that the liquid-filled container 13 and the mounting member 14 constitute a closed container 9.

Thus, the end portion 5a of the passage 5 is airtightly connected to the groove 14B communicating with the hole 19a of the pipe portion 19 via the pipe joint 22. Further, the end portion 5b of the passage 5 is connected to the groove 14C via a pipe joint 24. This groove 14C communicates with the hole 18 via the gas exhaust passage 11 provided in the mounting member 14. .

On the other hand, 25 is a magnifying glass attached to the outer peripheral surface of the liquid filling container 13, and includes a convex lens 26 and a convex lens 26 for magnifying and visually confirming the vicinity of the opening end of the ventilation nozzle 10.
6 (see FIG. 3).

The holding member 27 is made of an abbreviated plate member, and the convex lens 26 is fitted into a holding hole 27c provided in the long piece 27a. The long piece part 21a is disposed so as to be in contact with the outer peripheral surface of the liquid filling container 13, and the short piece part 27b is provided with the screw 2.
It is fixed to the fixing plate 16 via 8.

Next, the operation of this configuration will be explained.

When the pressurized gas supply source 2 shown in FIG. The container l is supplied and filled.

At this time, when gas is supplied to the ventilation nozzle 10 via the passage 3.5a, gas is simultaneously supplied to the liquid-filled container 13 via the passages 3.4 and 5b, so that the nozzle 1
If the pressure applied on the liquid level of 0 and the pressure applied on the liquid level of the liquid filling container 13 are in balance, and if surface tension, capillarity, etc. in the nozzle 10 are ignored, the liquid level height in the nozzle 10 and the liquid filling are The height of the liquid level in the container 13 will be approximately the same. Here, when the inside of the hollow container 1 reaches a predetermined pressure, the electromagnetic on-off valve 8 is closed. At this moment, the pressure applied to the liquid level of the nozzle 1O and the pressure applied to the liquid level of the liquid filling container 13 are maintained in equilibrium.

If there is a pinhole or a welding defect in the hollow container 1, gas will leak from that location, and the pressure inside the liquid-filled container 13 will gradually decrease.

As a result, the pressure inside the passage 5a becomes relatively higher than that in the passage 5b, so that gas flows into the nozzle 10.

When the gas leaks as described above, the liquid in the nozzle 10 is gradually pushed downward and reaches the liquid filling container 13. Therefore, the liquid level height in the nozzle 10 gradually decreases, and when the liquid in the nozzle 10 is completely pushed out, the gas from the nozzle IO is discharged into the liquid-filled container 13. Bubbles are generated.

The moving state of the liquid level in the nozzle 10 and the bubbles generated thereafter are enlarged and visually recognized by the enlargement m25.

As described above, the presence or absence of gas leakage from the hollow container 1 can be determined by visually checking whether the liquid level inside the nozzle 10 moves and changes and whether air bubbles are generated inside the liquid-filled container 13. I can do it.

According to this configuration, even if the diameter of the ventilation nozzle 10 is made extremely small, the magnifying glass 25 can be used to enlarge the minute bubbles in order to promptly generate bubbles in response to minute leaks and improve leak detection accuracy. easily visible.

Note that the ventilation nozzle 10 may be made of a transparent material, and a scale may be attached to the tip thereof. In this case, the nozzle 10 may be
The change in the liquid level inside the nozzle 10 can be easily determined, and the presence or absence of gas leakage can also be known from the change in the liquid level inside the nozzle 10.

Moreover, the minute scale of the nozzle 10 can be enlarged and visually recognized using the magnifying glass 25.

<Effects of the Invention> As explained above, according to the present invention, there is provided a leak inspection device that detects the presence or absence of air bubbles generated in a liquid-filled container by introducing gas into the container through a ventilation nozzle. , because a magnifying glass was provided to magnify and visually check the vicinity of the opening end of the ventilation nozzle from the outer periphery of the liquid filling container.
Improve leak detection accuracy (even if the diameter of the ventilation nozzle is made extremely small, microbubbles can be easily seen with the naked eye, improving the reliability of leak tests).

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an embodiment of the leak testing device according to the present invention, FIG. 2 is a diagram showing a schematic structure of a leak testing system to which the above leak testing device is applied, and FIG. 3 is the same as that shown in FIG. 1. It is a sectional view taken along the middle ■-■ arrow. 1...Hollow container IO...Vent nozzle 13...Liquid filling container 25...Magnifier Patent applicant Japan Automation Co., Ltd. Agent
Patent Attorney Sen 1) Minoru Figure 1

Claims (1)

[Scope of Claims] In a leak testing device disposed in a supply system for pressurized gas supplied to an object to be inspected or in a discharge system for leak gas from an object to be inspected, at least one part of the peripheral wall is provided. It consists of a liquid-filled container having a transparent part at the bottom, and a transparent thin tube in which the vicinity of the open end of the container is immersed in the liquid, and the liquid level in the tube is normally located at a predetermined height from the open end. a magnifying glass disposed opposite to the outer surface of the transparent peripheral wall of the container so as to be able to see through the vicinity of the opening end of the ventilation nozzle, 1. A leak testing device characterized in that it is possible to visually detect fluctuations in the temperature and/or bubbles discharged from a nozzle.