JPH0230745Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is a pipe opening closing device, in particular, for closing the opening of a vent pipe, etc. connected to a liquid tank storing a flexible liquid, during vacuum leakage inspection of the tank. The present invention relates to a pipe opening closing device for use in pipe openings.

(Prior art) In Fig. 2, 1 is an underground tank, 2 to 5 are ventilation pipes and measuring pipes connected to the underground tank 1, respectively.
A liquid supply pipe and a suction pipe, 6 is a liquid such as gasoline stored in an underground tank 1, 7 is a small airtight container, 8 is a vacuum pump, 9 is an on-off valve, 10 is a reference pressure source, 11
indicates a manometer, and when performing a leakage test on such an underground tank 1, first cover the ventilation pipe 2 and the liquid supply pipe 4 to make the tank 1 airtight, open the on-off valve 9, and turn on the vacuum pump 8. The suction pipe 5 is driven to apply a negative pressure to the suction pipe 5 through the container 7 to draw up the stored liquid 6 in the tank 1, and the pumped liquid is stored in the container 7. The chain line indicates the liquid level before pumping.

With the pressure in the internal space of the tank 1 reduced in this way, the on-off valve 9 is closed and the suction pipe 5 is sealed. At this time, a difference H between the pressure of the reference pressure source 10 occurs in the manometer 11 depending on the reduced pressure state in the tank 1.

However, when there is a leak in the tank 1, etc., air enters from the outside because the pressure inside the tank 1 is reduced, and as a result, the pressure inside the tank 1 increases over time, so the pressure difference H on the manometer 11 increases.
becomes smaller. Therefore, if this pressure difference H decreases, this indicates that there is a leak in the tank 1, and necessary measures are taken. Furthermore, since there is no leakage in the tank 1 unless the pressure difference H decreases, the on-off valve 9 is opened, the container 7 is opened, and the stored liquid is returned to the tank 1.

In this way, during inspection, it is necessary to put a blind cover on the ventilation pipe 2, etc., but the ventilation pipe 2 generally has a height of 2 to 5 m, and the blind cover is tightened and fixed to the top of the pipe by screwing etc. Not only was it difficult to do so, but it also had the disadvantage that it was impossible to confirm whether or not it had been installed airtight.

(Object of the invention) The object of the invention is to obtain a pipe opening closing device that does not have the above-mentioned drawbacks.

(Structure of the invention) The pipe opening closing device of the invention includes a non-breathable flexible inner bag which is placed over the opening of the pipe and whose open end is airtightly fixed to the outer circumference of the pipe, and which is covered by the inner bag. The bag is characterized by comprising a non-breathable flexible outer bag whose open end is airtightly fixed to the pipe below the open end fixing part of the inner bag.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In the present invention, as shown in FIG. 1, for example, a piece of vinyl or the like with protrusions 13 on the outer periphery is covered over the opening of the ventilation pipe 2 and the open end is fixed to the outer periphery of the ventilation pipe with an adhesive tape 12. A non-breathable flexible inner bag 14 and a material made of vinyl or the like which is covered by the inner bag 14 and whose open end is fixed to the ventilation pipe 2 with an adhesive tape 12 below the open end fixing part of the inner bag 14. A pipe opening closing device is constituted by the non-breathable flexible outer bag 15.

Since the device of the present invention has the above-described configuration, when the inside of the underground tank 1 is depressurized for leakage inspection, the air inside the inner bag 14 is sucked out and the inner bag 14 is deflated. If the outer bag 15 is completely closed, the outer bag 15 will not deflate, but if the inner bag 14 is not completely blocked, the air in the space between the inner bag 14 and the outer bag 15 will also be sucked into the tank. Outer bag 1
5 comes into close contact with the inner bag 14, and the deformation of the inner bag 14 due to the protrusion 13 becomes visible from the outside of the outer bag 15.

Therefore, by observing the change in the external shape of the outer bag 15, it is possible to very easily check whether the pipe opening is completely blocked, and appropriate measures can be taken.

In the present invention, since leakage can be confirmed if the external shape of the outer bag 15 changes, the protrusion 13 on the inner bag 14 is not necessarily necessary, and instead of using this protrusion 13, the inner bag 14 is colored. Of course, the outer bag 15 may be made transparent so that it can be visually confirmed from the outside that the two are in close contact with each other.

(Effects of the Invention) As described above, the device of the present invention has the great advantage of being able to close pipe openings with an extremely simple configuration and to confirm the fact.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the device of the present invention, and FIG. 2 is an explanatory diagram of an underground tank. 1... Underground tank, 2... Ventilation pipe, 3... Measurement tube, 4... Liquid supply pipe, 5... Suction pipe, 6... Liquid,
7...Small airtight container, 8...Vacuum pump, 9...
Opening/closing valve, 10... Reference pressure source, 11... Manometer, 12... Adhesive tape, 13... Protrusion, 14...
...Inner bag, 15...Outer bag.

Claims (1)

[Scope of utility model registration request] a non-breathable flexible inner bag that is covered over the opening of the pipe and whose open end is airtightly fixed to the outer periphery of the pipe; and a part that is covered by the inner bag and whose open end is fixed to the open end of the inner bag. A pipe opening closing device comprising a non-breathable flexible outer bag that is airtightly fixed to the pipe at a lower side.