JPH10311770A - Helium airtightness testing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the consumption amount of helium and to sharply reduce running costs by a method wherein a helium collection route which comprises a collection container is provided, a collected-helium introduction route is provided and collected helium is reused. SOLUTION: A helium collection route 105 which comprises a collection container 26 and a collected-helium introduction route 106 are installed inside a testing apparatus. Then, an object S, to be tested, inside a bell jar T is first evacuated to a prescribed vacuum. After that, an automatic valve 1 is closed, an automatic valve 27 is opened, and helium inside the collection container 26 is introduced into the object S, to be tested, via the automatic valve 27 and an automatic valve 2a by means of a pressure difference. Then, the leak amount of the helium is measured via a prescribed process, and whether the object S to be tested is good or not is judged. When its judgment is completed, the air is introduced into the ball jar T, an automatic valve 16a and an automatic valve 25 are opened, and the helium inside the object S to be tested is collected into the container 26 by means of a pressure difference. After that, the residual helium inside the object S to be tested is evacuated, the air is introduced, and a test is completed. Consequently, the consumption amount of the helium can be reduced sharply.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helium airtightness test apparatus, for example, the airtightness performance of a machine part, a container, etc. requiring airtightness, the state of a cast product or the state of a welded part, etc. The present invention relates to a helium hermeticity test device for judging by helium.

[0002]

2. Description of the Related Art For example, a compressor housing component and the like are required to have airtightness at a compression pressure and a predetermined strength capable of withstanding a high pressure. When such a component is manufactured, for example, from an aluminum cast product, the occurrence of "spot" during casting may cause a decrease in airtightness and a decrease in strength. A helium airtightness test device is used as one of the devices for checking the presence or absence of such "stain", minute cracks, poor welding, and the like of a cast product.

In general, a helium hermetic test apparatus sets a test sample in a jig called a bell jar, evacuates the inside of the test sample and the inside of the bell jar, which is the outside of the test sample, and then places the test sample in a predetermined position. A helium leak detector measures the amount of helium leaking into the bell jar through the test body by filling it with helium at a pressure, and performs a hermeticity test of the test body. A route to fill the body with helium,
A path for measuring the amount of helium leaked into the bell jar is provided.

FIG. 6 is a system diagram showing an example of a conventional helium airtight test apparatus. This helium tightness tester is
It has five systems of test circuits, and each test circuit is provided with a bell jar T for accommodating a test object S.

For example, when performing a test on a test piece S set in the bell jar T of the first test circuit shown at the top in FIG. 6, first, the automatic valve 1 and the automatic valve 2 are opened, and the vacuum pump is opened. The vacuum evacuation of the specimen S is performed by 3. When the predetermined evacuation is completed, the automatic valve 1 is closed and the automatic valve 4 is closed.
Is opened, and helium in the high-pressure helium container 5 flows from the manual valve 6, the manual valve 7, the pressure regulator 8 and the automatic valve 4 to the automatic valve 2.
Is supplied into the test body S through When the filling of the test piece S with helium at a predetermined pressure is completed, the automatic valve 2 and the automatic valve 4
Is closed, the automatic valve 9 is opened, and helium in the pipe between the automatic valve 2 and the automatic valve 4 is released.

The state in which the test piece S is pressurized with helium at a predetermined pressure is held for a predetermined time, and when it is confirmed that no pressure drop occurs, the automatic valve 10 is opened and the vacuum pump 11 opens the vacuum in the bell jar T. Exhaust is performed. When the inside of the bell jar T reaches a predetermined degree of vacuum, the automatic valve 10 is closed and the automatic valve 12 is closed.
Is opened, the gas in the bell jar T is sucked by the vacuum pump 13, the helium leak detector 14 measures the amount of helium leak, and the pass / fail of the specimen S is determined.

When the pass / fail judgment is completed, the automatic valve 12 is closed, the automatic valve 15 is opened, air is introduced into the bell jar T, and the automatic valves 16 and 17 are opened to release helium in the test sample S. Then, the automatic valve 17 is closed and the automatic valve 18 is opened, and the helium remaining in the specimen S is exhausted by the vacuum pump 19. Finally, the automatic valve 20 is opened, and air is introduced into the specimen S from the pressure regulator 21 via the automatic valve 20 and the automatic valve 16. After that, the bell jar T is opened to exchange the specimen S, and the next specimen S is tested.

As shown in FIG. 6, in a helium hermetic test apparatus having five test circuits, the above-described operation is performed for each test circuit at predetermined time intervals, and a test piece is continuously inspected for leaks.

[0009]

In such a conventional helium hermetic test apparatus, all the helium filled in the test body is released to the outside after the leak test, so that the helium filled in the test body is adapted to the volume and the pressurized pressure of the test body. Consumes an amount of helium. For example, the volume on the inner side of the test piece when set to a bell jar is 0.1 liter, and the pressurizing pressure is 17 kg / cm.
^In the case of ² G, 1.8 L of helium was required for one test piece, which had a large effect on running costs.

Therefore, the present invention can reduce the consumption of helium in a helium airtightness test apparatus for performing a leak test of a test piece by the above-mentioned bell jar method (pressurization method), and greatly reduce the running cost. It is an object of the present invention to provide a helium tightness test device that can perform the test.

[0011]

In order to achieve the above object, a helium hermetic test apparatus according to the present invention comprises: a specimen exhaust path having a vacuum pump for evacuating a specimen housed in a bell jar; A helium supply path for supplying helium at a predetermined pressure to the helium, a measurement path having a helium leak detector and a vacuum pump for evacuating the bell jar and measuring the amount of helium leaked from the specimen, and after measuring the leak amount. A helium recovery path having a recovery container for recovering helium in the test body by a pressure difference, an air introduction path for returning the test body and the inside of the bell jar to atmospheric pressure, and a pressure of helium in the recovery container in the test body. And a recovery helium introduction path introduced by a difference.

[0012]

FIG. 1 is a system diagram showing an example of a helium airtightness test apparatus according to the present invention, which is a helium airtightness test apparatus having five test circuits in the same manner as described above. The same components as those in the conventional helium hermetic test apparatus shown in FIG. 6 are denoted by the same reference numerals, and detailed description is omitted.

First, as shown in FIG. 1, the helium hermetic test apparatus shown in this embodiment also has five test circuits A, B, C, D, and E as described above. Is provided with a bell jar T for accommodating the test body S.

Each of the test circuits A to E has a common path from each test object S housed in the bell jar T to the automatic valve 2.
a to 2e and an automatic valve 1 connected to a vacuum pump 3 to evacuate the specimen S to a specimen exhaust path 101
And a high-pressure helium container 5 filled with high-pressure helium
Through the manual valve 6, the manual valve 7, the pressure regulator 8, the automatic valve 4, and the automatic valves 2a to 2e to connect to each specimen S, and to supply and fill helium at a predetermined pressure into each specimen S. Helium supply path 102 and a helium discharge path 103 in a pipe having an automatic valve 9 branched from the helium supply path
And a helium leak detector 14 and a vacuum pump 13 from inside each of the bell jars T through automatic valves 12a to 12e.
And a measurement path 104 for measuring the amount of helium leakage from the specimen S by evacuating the interior of each bell jar T.
A helium recovery path 105 for connecting the helium in the test specimen S from the inside of each test specimen S via the automatic valves 16a to 16e and the automatic valve 25 to the helium in the test specimen S after the leak amount measurement by a pressure difference; The recovery helium is connected from the recovery container 26 to each test piece S via the automatic valve 27 and the automatic valves 2a to 2e, and the helium in the recovery container 26 is introduced into each test piece S by a pressure difference. Introduction route 1
06, a helium exhaust path 107 for exhausting helium remaining in the specimen S from the inside of each specimen S through the automatic valves 16a to 16e and the automatic valve 17 to near atmospheric pressure, and an automatic valve in the helium exhaust path. A helium evacuation path 1 for branching from the upstream of 17 and connecting the automatic valve 18 to the vacuum pump 19 to evacuate the helium remaining in the specimen S.
08, and an air introduction path 109 for connecting the pressure regulator 21 to each specimen S through the automatic valve 20 and the automatic valves 16a to 16e to introduce air into each specimen S. I have. Each bell jar T has an automatic valve 10a.
Evacuating paths 110a to 110e having bell jars having vacuum pumps 11a to 11e and automatic valves 15a
Air introduction path 111a-1 in the bell jar having
11e are provided respectively.

Next, the apparatus will be described based on the operation procedure in one test circuit A. In the first state of the description, each automatic valve is in a closed state, each manual valve is in an open state,
The pressure regulator is set to a predetermined pressure, each vacuum pump and the helium leak detector are in an operating state, and the recovery container is filled with helium at an appropriate pressure.

First, when the test piece S is set in the bell jar T, the automatic valve 1 and the automatic valve 2a open, and the vacuum pump 3
As a result, the inside of the specimen S is evacuated until, for example, 10 ⁻² Torr. When the prescribed evacuation is completed,
The automatic valve 1 is closed, the automatic valve 27 is opened, and the helium in the collection container 26 is discharged from the automatic valve 27 via the automatic valve 2a to the test piece S
Introduced within. The introduction of helium from the collection container 26 to the specimen S is performed by a pressure difference between the collection container 26 and the specimen S, and is performed until the pressures of both are substantially balanced.

Next, the automatic valve 27 is closed and the automatic valve 4 is opened, and the helium in the high-pressure helium container 5 is tested through the manual valve 6, the manual valve 7, the pressure regulator 8, the automatic valve 4 and the automatic valve 2a. It is supplied into the body S. When the filling of the helium at a predetermined pressure, for example, 17 kg / cm ² G into the specimen S is completed, the automatic valves 2a and 4 are closed and the automatic valve 9 is opened,
Helium in the pipe between the automatic valve 2a and the automatic valve 4 is released.

The state in which the test piece S is pressurized with helium at a predetermined pressure is maintained for a predetermined time, and when it is confirmed that the pressure does not drop, the automatic valve 10a is opened and the vacuum in the bell jar T by the vacuum pump 11a is opened. Exhaust is performed. When the inside of the bell jar T reaches a predetermined degree of vacuum, for example, 10 ^-3 Torr, the automatic valve 10a closes, the automatic valve 12a opens, and the vacuum pump 1
The gas in the bell jar T is sucked by 3 and the amount of helium leak is measured by the helium leak detector 14 to determine whether the test sample S is acceptable or not.

When the pass / fail judgment is completed, the automatic valve 12a is closed, the automatic valve 15a is opened, air is introduced into the bell jar T, and the inside of the bell jar T returns to the atmospheric pressure. The helium in the specimen S is opened and collected in the collection container 26. The recovery of helium from the specimen S into the collection container 26 is also performed with the specimen S and the collection container 26.
And until the two pressures are substantially balanced.

When the recovery of helium into the recovery container 26 is completed, the automatic valve 25 is closed and the automatic valve 17 is opened.
Helium remaining in the specimen S is released to near atmospheric pressure through the automatic valve 16a and the automatic valve 17, and then discharged to the vicinity of the atmospheric pressure.
Is closed, the automatic valve 18 is opened, and the helium remaining in the specimen S is exhausted by the vacuum pump 19. Finally, the automatic valve 20 is opened, and the automatic valve 20 and the automatic valve 1
Air is introduced into the specimen S through 6a.

Thereafter, in the test circuit A, the bell jar T is opened to replace the test piece S, and a leak test of the test piece S in the next test circuit B is performed. In the leak test of the test piece S in the test circuit B, the helium collected in the collection container 26 is reused as the helium to be filled in the test piece S up to the intermediate pressure. Helium in the high-pressure helium container 5 is newly used in the range. Hereinafter, each of the test circuits A to E
In the step S, a leak test of the specimen S is performed. Note that the evacuation or the introduction of the gas in the test piece S or the like may be terminated by detecting the pressure, or may be performed at a set time.

As described above, the helium in the specimen S is collected in the collection container 26 after the leak inspection and reused, so that the helium consumption required for the leak inspection can be greatly reduced. For example, in the same manner as described above, the volume on the inner side of the test piece is 0.1 liter, and the pressurizing pressure is 17 kg /
In the case of cm ² G, if a recovery vessel of about 1 liter is provided and helium is reused, the amount of helium required for one specimen can be calculated to be about 0.89 liter. Therefore, a leak test similar to the conventional one can be performed with about half the amount of the conventional helium, and the helium consumption can be greatly reduced.

The volume of the collection container may be set according to various conditions such as the volume inside the test specimen, the filling pressure, the number of test specimens to be tested at a time, and the length of the pipe.
In addition, it is preferable that the recovery container is previously filled with helium at an appropriate pressure as an initial filling, but the pressure is preferably about 10 kg / cm ² G.

FIGS. 2 and 3 show an example of a test body for performing a leak test with the helium airtightness test apparatus of the present invention and a bell jar for accommodating the test body. FIG. 2 is a sectional view showing a state where the bell jar is opened. FIG. 3 is a sectional view showing a state in which the bell jar is closed.

The test piece S shown here is a cap material made of an aluminum casting having a shaft hole 31 through which the rotary shaft of the compressor is inserted, and includes a large-diameter portion 32 fitted to the compressor main body, A small-diameter portion 33 having a hole 31 and an outer peripheral flange 34 are provided. The bell jar T that accommodates the test body S is composed of a lower fixing jig 41 and an upper fixing jig 51.
An O-ring 43 which has a ring-shaped insertion groove 42 having an open top for inserting the large-diameter portion 32 of the specimen S, and which is in contact with the flange 34 of the specimen S,
And an O-ring 44 abutting on the lower surface of the upper fixing jig 51. Further, a gas guide block 45 is provided on the inner peripheral side of the insertion groove 42.

The upper fixing jig 51 is made of a cylindrical body with a lid that hermetically covers the test piece S protruding from the upper surface of the lower fixing jig 41. A flange 53 whose lower surface is in contact with the O-ring 44 is provided, and an inner communication pipe 55 communicating with the inside of the specimen S at the center and an external communication pipe communicating with the outside of the specimen S are provided at the center of the lid 54. And a spring 57 for pressing the specimen S in the direction of the lower fixing jig 41, and a ring-shaped push plate 58 are provided on the lower surface of the lid 54. 52, the flange 3 of the specimen S
A ring-shaped push plate 59 for pressing the 4 to the lower fixing jig 41 is provided. Further, the internal communication pipe 5
5 is provided with a protruding portion 60 that enters the shaft hole 31 of the test sample S, and two O-rings 61 that are in contact with the inner peripheral surface of the shaft hole 31 are provided on the outer periphery of the protruding portion 60. A fitting hole 62 into which the gas guide block 45 is fitted is provided in the protrusion 60. The spring 5
7 are provided at equal intervals on the same circumference so that the test body S can be pressed uniformly via the push plate 58.

When the leak test of the test piece S is performed using the bell jar T, first, as shown in FIG. 2, the lower fixing jig 41 and the upper fixing jig 51 are opened and the lower jig 51 is opened. The large diameter portion 32 of the test sample S is set in the insertion groove 42 of the fixing jig 41 so as to be inserted. Next, the lower fixing jig 4
1 and the upper fixing jig 51 are united, and as shown in FIG. 3, the test piece S is sandwiched between the two jigs. Thus, the inside and outside of the bell jar T are air-tightly partitioned by the O-ring 44, and the inside and outside of the test body S in the bell jar T are air-tightly separated by the O-ring 43 and the O-ring 61.

In this state, the inside of the specimen S is evacuated or filled with helium via the internal communication pipe 55 and the gas guide block 45, and the outside of the specimen is supplied via the external communication pipe 56. A vacuum inspection is performed by evacuating the side.

When the lower fixing jig 41 is separated from the upper fixing jig 51 after the end of the leak test, the test piece S separates from the upper fixing jig 51 by the action of the spring 57 and is placed on the lower fixing jig 41. State. Therefore, the setting of the test piece S in the bell jar T can be performed only by placing the test piece S on the lower fixing jig 41 apart from the upper fixing jig 51. Since it is only necessary to remove the specimen S upward from the lower fixing jig 41, the specimen S can be attached and detached very easily, and the workability when testing a large number of specimens S is greatly improved. Can be improved.

4 and 5 show an example of the configuration of a leak inspection unit in the helium airtightness test apparatus. FIG. 4 is a schematic plan view, and FIG. 5 is a schematic front view for explaining an operation sequence. This helium tightness test apparatus is designed to perform a test with two bell jars T accommodating the test specimen S, and as described above, the lower fixing jig 41 and the upper fixing jig 5
1 and two upper fixing jigs 51 of the bell jar T formed on the upper fixing plate 71, and two lower fixing jigs 41 are respectively installed on five lower movable plates 72a to 72e. I have. Below the upper fixing plate 71, a lower fixing jig 4 installed on the lower movable plates 72a to 72e is provided.
1 is fixed to the upper fixing jig 5 fixed to the upper fixing plate 71.
1, a cylinder (not shown) for moving the lower fixing jig 41 directly below the upper fixing jig 51 is provided on each of the lower movable plates 72a to 72e. ) Are provided respectively.

The upper fixing jig 51 is provided with an internal communication pipe 55 and an external communication pipe 56 in the same manner as described above, and the internal communication pipe 55 is provided with the test object exhaust path 10.
1, helium supply path 102, helium recovery path 10
5, Recovery helium introduction path 106, helium exhaust path 1
07, helium evacuation path 108 and air introduction path 1
09 is connected to the external communication pipe 56 and the measurement path 1
04, a vacuum exhaust path in the bell jar and an air introduction path in the bell jar.

In the helium hermeticity test apparatus thus formed, the specimen S is placed on the lower fixing jig 41 on the lower movable plates 72a to 72e, and as shown in FIG. The plate 72a is moved forward to move the lower fixing jig 41 directly below the upper fixing jig 51 (FIG. 5B), and the lower fixing jig 41 is raised by the piston 73 of the ascending cylinder to thereby move the upper fixing jig. After combining with FIG. 51 (FIG. 5)
(C)) The above-mentioned predetermined leak test is simultaneously performed on two test specimens via the internal communication pipe 55 and the external communication pipe 56. When one leak test is completed, lower fixture 4
1 is lowered (FIG. 5D), and the lower movable plate 72a is retracted to the original position (FIG. 5E).
2b is advanced and the same operation is repeated.

As described above, the upper fixing jig 51 is fixed to the upper fixing plate 71, the lower fixing jigs 41 are respectively installed on the plurality of lower movable plates 72, and the lower fixing jigs 41 are sequentially moved. By conducting the test, the lower fixing jig 4
The setting of the test piece S to 1 and the leak test of the test piece S can be performed in parallel, and the test efficiency can be increased. In addition, one upper fixing jig 51 may be prepared for a plurality of lower fixing jigs 41, and in this example, one upper fixing jig 51 may be prepared for every five. By doing so, the equipment can be greatly simplified. In particular, the lower movable plate 7 that moves the lower fixing jig 41 linearly.
2, the positional accuracy can be easily improved.

The shape of the bell jar can be formed in an arbitrary shape according to the shape of the test piece. Each piping path in the helium hermetic test apparatus also depends on the number of test circuits, the condition of the test piece, and the like. An optimal configuration can be appropriately selected according to the situation.

[0035]

As described above, according to the helium tightness test apparatus of the present invention, the consumption of helium can be greatly reduced, and the running cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a system diagram showing one embodiment of a helium airtightness test apparatus according to the present invention.

FIG. 2 is a sectional view showing a state where a bell jar accommodating a test body is opened.

FIG. 3 is a sectional view showing a state in which the bell jar is closed.

FIG. 4 is a schematic plan view showing a configuration example of a leak inspection unit in the helium airtightness test device.

FIG. 5 is a schematic front view for explaining the operation sequence.

FIG. 6 is a system diagram showing an example of a conventional helium tightness test apparatus.

[Explanation of symbols]

5: High pressure helium container, 14: Helium leak detector, 26: Recovery container, 101: Exhaust path of test specimen, 102
... helium supply path, 103 ... helium release path in pipe, 104 ... measurement path, 105 ... helium recovery path, 1
06: recovered helium introduction path, 107: helium exhaust path, 108: helium vacuum exhaust path, 109: air introduction path, S: specimen, T: bell jar

Claims (1)

[Claims] 1. A specimen exhaust path having a vacuum pump for evacuating a specimen housed in a bell jar, a helium supply path for supplying helium at a predetermined pressure into the specimen, and evacuating the bell jar. A measurement path having a helium leak detector and a vacuum pump for measuring the amount of helium leaked from the test body, and a helium collection path having a collection container for collecting the helium in the test body after the leak amount measurement by a pressure difference, A helium airtight test comprising: an air introduction path for returning the inside of the test body and the bell jar to atmospheric pressure; and a recovery helium introduction path for introducing helium in the recovery container into the test body by a pressure difference. apparatus.