JPH02673Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to a leak test device used for leak testing of welded parts of test objects such as solenoid valves and diaphragm parts.

(B) Prior Art In a conventional leak test apparatus, a test object is connected to a test object connection holder provided in a vacuum chamber, and helium gas is introduced from the holder into the test object. Then, a leak detector detects the amount of helium leaking from the welded portion, which is the inspection location of the test object.

However, since helium gas tends to leak into the chamber from the joint between the test object and the holder, there is a drawback that the amount of leakage cannot be measured with high accuracy.

(c) Purpose The purpose of this invention is to provide a leak test device that can prevent a decrease in the accuracy of measuring the amount of leakage caused by helium gas leaking from the joint between the test object and the holder.

(D) Structure This device is a leak test device that introduces a probe gas into a test object and detects the amount of leakage. and an external vacuum chamber formed by the test object and the holder, the internal vacuum chamber communicates with a leak path at the joint between the test object and the holder, and is connected to evacuation means, and the external vacuum chamber at least It is characterized by housing the inspection part of the test specimen and being connected to a vacuum evacuation means and a leak detector.

(e) Embodiment FIG. 1 is an explanatory diagram schematically showing the structure of an embodiment of a leak test device according to the invention.

In the figure, 1 is an internal chamber, and the inside of this internal chamber 1 forms an internal vacuum chamber. 2
is an external chamber, and the space between the internal chamber 1 and the external chamber 2 forms an external vacuum chamber. 3 is a base plate on which the inner chamber 1 and outer chamber 2 are placed. Also 41
45 are rubber gaskets as sealing materials provided at the joints of each component.

Reference numeral 10 denotes a test object (for example, a solenoid valve) whose sealing state of the welded portion 11 is inspected. The test object 10 is screwed onto a joint 21 of a holder 20 that opens into an external vacuum chamber through a hole provided at the top of the internal chamber 1 . Thus, at least the welded portion 11, which is the inspection point, is provided in the external vacuum chamber.

The holder 20 is provided with a helium gas communication hole 22 that opens to the bottom of the holder 20 and the joint portion 21 . Therefore, from the rubber gasket 44 to the joint portion 21
A slight gap existing along the screwing surface of the through hole 22 may become a leak path through which the helium gas introduced from the through hole 22 leaks. A small hole 23 is provided in the side wall of the holder 20 to communicate this leak path with the internal vacuum chamber.

30 is provided at the center of the base plate 3,
This is a chuck that is a means for fixing the holder 20. The chuck 30 includes a cylindrical support portion 31 into which the lower portion of the holder 20 is inserted, and a screw lid 32 that is inserted through the holder 20 and screwed into the support portion 31. This screw-on lid 32 seals between the holder 20 and the support portion 31 by pressing the rubber gasket 45 through the press ring 33. Also,
The support portion 31 is provided with a gas introduction hole 51 for introducing helium gas into the conduction hole 22 of the holder 20 .

On the other hand, an exhaust hole 52 is provided in the base plate 3 of the internal vacuum chamber. The internal vacuum chamber is evacuated from this exhaust hole 52 by a vacuum pump 71 via a valve 61.

Furthermore, on the base plate 3 of the external vacuum chamber,
An exhaust hole 53 is provided. The external vacuum chamber is evacuated from this exhaust hole 53 by a vacuum pump 72 via a valve 62. The exhaust hole 53 is also connected to a leak detector 80 via a valve 63. The leak detector 80 detects the amount of helium gas leaked from the weld 11 of the test object 10 into the external vacuum chamber.

Next, the operation of the embodiment having the above-described configuration will be explained.

Before introducing helium gas into the test object 10, valves 61 and 62 are opened (valve 63 is closed) to evacuate the external vacuum chamber and the internal vacuum chamber so that no pressure difference is created. Next, the valve 62 is closed to introduce helium gas into the test object 10, and the valve 63 is opened to introduce the helium gas into the test object 10.
Detect a leakage amount of 0.

At this time, even if helium gas leaks at the joint between the test object 10 and the holder 20, this helium gas is led out to the internal vacuum chamber through the small hole 23 provided in the leak path. It almost never enters the vacuum chamber.

In addition, in the above-mentioned embodiment, one test object 10
We have explained the case of measuring . However, this invention is not limited to this; for example, as shown in FIG. 2, a plurality of test objects may be measured simultaneously. In this figure, the same parts as in FIG. 1 are indicated by the same reference numerals.

(f) Effect The leak test device according to this invention has an internal vacuum chamber that extracts helium gas leaking from the joint between the test object and the holder, and an external vacuum chamber that collects the helium gas leaking from the test object and the inspection location. Since it is equipped with a separate vacuum chamber, the measurement of the leakage amount of the test object is not affected by the leaked helium gas of the former. Therefore, according to this idea,
The leakage amount of the test object can be measured with high accuracy.

Further, since the influence of leakage at the joint between the test object and the holder is extremely low, a large number of test objects can be tested at once. Therefore, according to this invention, the accompanying effect of improving work efficiency can also be expected.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing the structure of an embodiment of the leak test device according to the invention. FIG. 2 is an explanatory diagram schematically showing an embodiment in which a plurality of test objects are measured. 1... Internal chamber, 2... External chamber, 3... Base plate, 10... Test object, 20... Holder,
23...small hole, 30...chuck part.

Claims (1)

[Claims for Utility Model Registration] A leak test device that introduces a probe gas into a test object and detects the amount of leakage, the leak test device comprising: an internal vacuum chamber formed by an internal chamber; and an external vacuum chamber formed by an external chamber, the internal vacuum chamber communicating with a leak path at the joint between the test object and the holder, and connected to evacuation means, the external vacuum chamber 1. A leak test device, which houses at least an inspection part of a test object and is connected to a vacuum evacuation means and a leak detector.