JPH04215028A - Airtightness testing device for cylindrical single-bottomed container - Google Patents

Abstract

PURPOSE:To improve the durability of an existing seal packing member so as to obtain an airtightness testing device suppressing the deformation of a cylindrical single-bottomed container at the testing time. CONSTITUTION:An airtightness testing device 10 for a cylindrical single- bottomed container 1 is formed of an air supply device 5 for supplying air into the interior 16 of the cylindrical single-bottomed container 1, a holder 2 inserted into the interior 16 of the container 1 at the testing time with an air supply passage 4 and an air branch passage 12 formed therein, an elastic seal packing member 9 provided around the outer peripheral surface of the holder 2, and a spool valve device 13 provided on the air supply downstream side of a branch part between the air supply passage 9 and the air branch passage 12. The spool valve device 13 leads air into the air branch passage 12 to expand the seal packing member 9 and thereby to seal on the container inner peripheral surface 1b in the first term of testing, and leads the air into the container interior 16 in the last term of testing after sealing to perform airtightness testing.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention uses a cylindrical container whose one end is sealed and the other end is open, that is, a cylindrical single-ended container, as the subject of a test, and tests the airtightness of this container for air leakage. Regarding test equipment.

0002

[Prior Art] For example, a cylindrical single-mouthed container is manufactured by cutting a cylindrical pipe to a predetermined length and sealing one end by means such as welding, or by extrusion molding with a punch or the like. On the other hand, when testing the airtightness, conventionally, an airtightness testing device as shown in FIG. 3 is used.

As shown in the figure, this device has an open end 1a of a container 1 whose axial movement is regulated by a wall member W.
The packing holder 32 equipped with the ring-shaped seal packing 31 is pressed against the air to prevent air leakage from the open end 1a, and then the air is supplied from the air supply means 5 to the inside of the container 1 via the air supply passage 32a. Air is sent in and the presence or absence of air leakage from the container 1 in this state is inspected. In FIG. 3, reference numeral 6 indicates an air source constituting the air supply means 5, 7 indicates a switching valve, and 8 indicates a pressure switch. Air is supplied by the air source 6 for a certain period of time, and when the pressure exceeds a predetermined value, the pressure switch is activated. When the switch 8 is turned ON, the switching valve 7 is closed, and whether or not a leak has occurred is determined based on the subsequent pressure depending on the operating state of the switch 8 (unless the ON state continues). (no omissions).

0004

[Problems to be Solved by the Invention] In the conventional airtightness testing apparatus as described above, when testing, the seal packing 31 is pressed against the open end 1a which is the edge of the container 1, and this part is inspected as shown in the figure. In order to seal the seal packing 3 by this open end 1a,
1 is easily damaged, and air leakage may occur from this seal. Therefore, as a countermeasure, when using the device,
It is necessary to frequently replace the seal packing 31, which adversely affects the running cost and inspection ability of the device.

[0005] In addition, in this inspection method, the container 1 is
Since the container 1 is pressed in its axial direction, the container 1 may be deformed depending on the pressing force, which may not be preferable for a container 1 that requires strict dimensional accuracy. The present invention is provided in view of these problems of conventional devices.

[0006]

[Means for Solving the Problems] In order to solve the problems, an airtightness test device for a cylindrical single-mouth container provided by the present invention includes an air supply means for supplying air into the inside of a cylindrical single-mouth container, and a cylindrical single-mouth container. A holder that is inserted into the single-mouthed container and has an air supply passage formed in the direction of insertion for guiding air from the air supply means to the cylindrical single-mouthed container; an elastic seal packing member whose end is airtightly fixed to the holder; and an opening on the outer circumferential surface of the holder that branches from the air supply passage and faces the inner circumferential surface of the elastic seal packing member. an air branch passage, and an air supply passage provided in the air supply passage downstream of the branch between the air supply passage and the air branch passage;
A valve means is provided for guiding the air introduced into the air supply passage into the inside of the container when the pressure inside the air branch passage is equal to or higher than a predetermined pressure.

[0007]

[Operation] In the early stage of the airtightness test until the internal pressure of the air branch passage reaches a predetermined pressure, the valve means guides air to the air branch passage, thereby supplying air to the gap between the elastic seal packing member and the holder. The resilient seal packing member gradually expands until the seal packing member and the inner circumferential surface of the container come into circumferential contact, providing a hermetic seal at this portion. While maintaining this state, in the latter half of the test when the pressure inside the air branch passage becomes equal to or higher than a predetermined pressure, the valve means supplies air into the container through the air supply passage to test the airtightness of the container.

[0008]

[Examples] Examples of the present invention will be described below with reference to the drawings.
explain. FIG. 1 shows the state of the airtightness test device (hereinafter abbreviated as the device) 10 according to the present example before the test (before air supply),
Further, FIG. 2 shows the operating state of the device 10 during an airtightness test (after air supply).

Regarding these figures, 1 is the object of inspection;
The device 10 is a cylindrical single-ended container with one side sealed, and the main part of the device 10 is inserted into the container 1 during an airtightness test. The device 10 includes a substantially cylindrical holder 2 having an inner diameter smaller than the inner diameter of the container 1 so as to be easily inserted into the container 1, and this holder 2 is attached to a base 3 of the device 10.
Fixed. An air supply passage 4 is formed in the center of the holder 2 and extends in its longitudinal direction so as to substantially coincide with the direction of insertion into the container 1 (direction of arrow 1).

One end of this air supply passage 4 is connected to an air supply device 5 which serves as an air supply source for an airtightness test to be described later, and the other end is formed to open at the tip of the holder 2. ing. The air supply device 5 includes an air source 6 typified by, for example, an air pump, a switching valve 7 located downstream of the air source 6, and a pressure switch 8 located further downstream of the switching valve 7. It is made up of. The structure of the air supply device 5 described above and the roles of each component are almost the same as those of the conventional device, and are unchanged in the present invention.

A cylindrical seal packing member 9 made of an elastic material such as rubber is provided on the outside of the holder 2 so as to cover its outer peripheral surface 2a. This seal packing member 9 has a flange portion 9 at one end, as shown in the figure.
a, the flange portion 9a is pressed from above by the base 3 on the shoulder portion 2b of the holder 2,
A sealing portion is provided between the flange portion 9a and the shoulder portion 2b. In addition, in order to ensure the airtightness of this part, this flange part 9a and the shoulder part 2 of the holder 2 are bonded, for example, with adhesive or the like.
b may be closely joined.

On the other hand, the other end of the seal packing member 9 has an end face 9b so as to cover the tip 2c of the holder 2, and the center thereof is open to provide the air supply passage 4, similar to the holder 2. do. A fixing member 11 having an axial passage 11a inside is inserted into the openings of the holder 2 and the seal packing member 9, and the end surface 9b of the seal packing member 9 is airtight with respect to the holder tip 2c. fixed in shape. Note that adhesive may be used in this portion as well. In this way, the seal packing member 9 is airtightly fixed to the holder 2 at its upper and lower ends, but the inner circumferential surface 9c of the seal packing member 9 that comes into contact with the holder outer circumferential surface 2a is attached to the holder 2. It will not be glued to the other side.

Inside the holder 2 in which the air supply passage 4 is formed, an air branch passage 12 is formed branching from the air supply passage 4 and directed toward the holder outer circumferential surface 2a, and finally a seal packing member 9 is formed. It opens in the holder outer circumferential surface 2a to face the inner circumferential surface 9c of the holder. As shown in the figure, two air branch passages 12 are formed in the diametrical direction of the holder 2 in this embodiment, but of course this number is not limited to this embodiment; for example, the number is not limited to the holder axis A. A large number of them may be formed radially around the center.

According to this embodiment, the holder tip 2
A spool valve device 13 as a valve means is interposed in the air supply passage 4 located on the c side (in other words, on the downstream side of the air supply during operation of the device). This spool valve device 13 includes a compression spring 14 that is attached to a valve body housing part 4a that is formed to have a larger diameter than the air supply passage 4, and a compression spring 14 that is housed in a reciprocating manner within this valve body housing part 4a. The spool valve body 15 is urged toward the air branch passage 12 by a compression spring 14 seated on the fixed member 11 mentioned above. Furthermore, this spool valve device 13 includes a bypass passage 4 outside the spool valve body 15 for bypassing this valve body 15 and allowing air to flow downstream.
It is equipped with b.

The above is the airtightness test device 1 in this embodiment.
The operation of the device 10 will be described below with reference to FIGS. 1 and 2. When testing the airtightness of the container 1, the holder 2 protruding from the base 3 is first inserted into the container 1, and then the air source 6 of the air supply device 5 is activated to supply air into the holder 2.

In the stage before the start of air supply shown in FIG. 1, the spool valve body 15 is pressed down in the figure by the compression spring 14, and the bypass passage 4b is therefore closed. As a result, the air supplied into the holder 2 is introduced between the holder outer circumferential surface 2a and the inner circumferential surface 9c of the seal packing member 9 through the air supply passage 4 and the air branch passage 12, and pressure is applied to the inner circumferential surface 9c. The seal packing member 9 is expanded while applying the pressure, and finally the seal packing member 9 and the inner circumferential surface 1b of the container 1 are brought into close contact with each other. Note that the initial setting load of the compression spring 14 is set at least until the pressure inside the air branch passage 12 is increased to the extent that the seal packing member 9 is in close contact with the inner circumferential surface 9c of the container and the inside 16 of the container is sealed from the outside at this portion. is set so that the spool valve body 15 does not move toward the holder tip 2c side.

If air supply is continued in the above-mentioned close contact state, the pressure in the air branch passage 12 will be reduced by the compression spring 1.
4, the pressure (predetermined pressure) is strong enough to push up the spool valve body 15. As a result, the bypass passage 4b, which had been closed by the spool valve body 15 until then, is now closed by the valve body 1 due to the displacement of the spool valve body 15.
5 It now communicates with the air supply passage 4 on the upstream side, and the air flow is now connected to the air supply passage 4 and the air branch passage 12.
Instead of the flow toward the inside of the container 16, the flow passes through the air supply passage 4, the bypass passage 4b, and the axial passage 11a of the fixing member 11 while keeping the seal packing member 9 in an expanded state. is filled with air (the state shown in Figure 2).

As described above, in the spool valve device 13 as a valve means according to the present embodiment, the seal packing member 9 is brought into close contact with the inner circumferential surface 1b of the container, and the pressure inside the air branch passage 12 is increased, so that the pressure inside the container 16 is increased at this portion. In the first half of the airtightness test (pressure inside the air branch passage <predetermined pressure) until a state where the air is sealed from the outside is achieved, the air introduced into the air supply passage 4 is guided to the air branch passage 12, and then, In the latter half of the test until the pressure inside the air branch passage reaches the predetermined pressure or higher and the pressure inside the container reaches the airtightness test pressure, the air introduced into the air supply passage 4 is guided to the inside of the container 16 via the bypass passage 4b. do the work.

When air is supplied to the inside of the container 16 for a certain period of time by the air supply device 5, the pressure inside the container reaches the airtightness test pressure, and the pressure switch 8 is turned on, the switching valve 7 is moved to the upper position in the diagram. and the supply of air to the interior 16 of the container is stopped. When this air supply stops, the spool valve body 15 is pushed down toward the air branch passage 12 by the biasing force of the compression spring 14, the bypass passage 4b is closed, and the air supply upstream side is connected to the spool valve device 13 as a boundary. Two pressure spaces downstream of the air supply are formed. However, if there is a slight air leak in the container 1, the pressure inside the container 16 will gradually decrease, and the above
The spool valve body 15 is pushed upward again by the pressure difference between the two pressure spaces, and communicates with the bypass passage 4b. As a result, the pressure in the space upstream of the air supply from the spool valve device 13 gradually decreases, and the pressure switch 8 is finally turned off, leading the tester to conclude that there is a leak in the container 1. can do. On the other hand, if the pressure switch 8 continues to be in the ON state, it means that the airtightness test pressure is maintained in the two spaces mentioned above, and therefore, the container 1 is judged to have sufficient airtightness. be able to. In addition, in the series of test operations described above, even if air is supplied to the inside of the container 16 for a certain period of time by the air supply device 5, if the pressure inside the container does not reach the airtightness test pressure and the pressure switch 8 still does not turn on. Naturally, there is a possibility that a relatively large leak has occurred in the container 1, and in this case, the container 1 will be judged as a defective product.

As described above, the airtightness test device 10 according to the present embodiment first closes the inside of the container 16 from the outside by supplying air to the holder 2, and then air for airtightness testing is supplied to the inside of the container 16. Therefore, there is no need for a pressurizing mechanism to achieve a seal at the edge of the container, which was conventionally seen, and since the contact area of the seal packing member 9 is not the edge of the container 1, the seal packing member 9 Durability is also improved.

The present invention has been described above using an example in which the valve means is a spool valve device equipped with a compression spring. An electromagnetic valve (not shown) may be used, which opens the valve and guides air into the container interior 16 when the pressure exceeds the pressure. In addition, the time from the start of air supply until the internal pressure of the air branch passage 12 reaches the above-mentioned predetermined pressure, which may change depending on the air supply characteristics of the airtightness testing device, the shape of the container, etc., may be input in advance. , is equipped with a timer means, which opens the valve at the predetermined time after air is supplied to supply air to the inside of the container 1.
A valve system (not shown) may be used, such as the one leading to 6.

[0022]

As explained above, according to the present invention, the inside of the container is sealed from the outside on the inner peripheral surface of the container by the expansion of the seal packing member. Improves durability. Further, the load applied to the container due to this seal is not an axial load as shown in the figure, which has a high influence on the deformation of a thin container, but a tensile force in the circumferential direction of the container, so that the amount of container deformation is extremely small.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the airtightness testing device according to the present invention in a state before operation.

FIG. 2 is a sectional view showing the state of the airtightness testing apparatus according to the present invention during an airtightness test.

FIG. 3 is a sectional view showing the configuration of a conventional airtightness test device.

[Explanation of symbols]

1...Cylindrical single-mouthed container 2...Holder 4...Air supply passage 5...Air supply device 9...Seal packing member 10...Airtightness test device 12...Air branch passage 13...Spool valve device

Claims (1)

[Claims] 1. An airtightness testing device for a cylindrical single-mouth container, comprising: an air supply means for supplying air into the cylindrical single-mouth container; , a holder in which an air supply passage is formed that guides air from the air supply means to the cylindrical single-mouthed container, and elasticity provided around the outer peripheral surface of the holder, the upper and lower ends of which are fixed to the holder in an airtight manner. an elastic seal packing member, an air branch passage branching from the air supply passage and opening on the outer circumference of the holder to face the inner circumference of the elastic seal packing member, an air supply passage and the air branch passage; Valve means is provided in the air supply passage downstream of the air supply branch to the air supply passage and guides the air introduced into the air supply passage into the container when the pressure inside the air branch passage is equal to or higher than a predetermined pressure. An airtightness test device characterized by: