JPS62144039A - Helium leak test method and apparatus therefor - Google Patents

Abstract

PURPOSE:To achieve a satisfactory inspection with a higher concentration of helium at a part required to be inspected in a helium hood, by mounting a manifold blowoff nozzle in a helium hood to blow a helium gas aiming at a part required to be inspected to an object to be measured. CONSTITUTION:First, an object 13 to be measured containing a part 14 required to be inspected of the object to be measured is evacuated with a rough suction pump 7 and a rough suction pump 6. Then, a helium hood 11 is lowered by an air cylinder 1 to cover the whole of the object 13 being measured containing the part 14 requiring inspected. Thereafter, a solenoid valve 4 for helium is opened to feed a helium gas into a helium hood 11 from a helium cylinder 5 and it is blown to the part 14 requiring inspection of the object 13 being measured from a blowoff nozzle 12 to make the concentration of the helium enough for a leak test. Then, the rough suction valve 6 is closed, a main suction valve 8 is opened to detect the leak with a leak detector 10. In this manner, the concentration of helium can be secured sufficiently, eliminating the possibility of a overlooking leak of above an allowable value.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a helium leak test method in which the inside of the object to be measured is evacuated and helium gas is blown from the outside to detect the total leakage amount of the object to be measured. Regarding the device.

(Prior art) In general, leak tests to detect leakage from pinholes in a sealed object are conducted using two methods: an internal pressure method that applies high pressure to the inside of the object and measures the pressure decrease; There is an external injection method that detects the leakage amount of the measured object by creating a vacuum and spraying helium gas from the outside. After evacuating it, it was covered with a helium hood to diffuse helium gas into the same hood, and the amount of leakage was detected with a helium leak detector.

FIG. 6 is an explanatory diagram of the main parts of the conventional helium leak test device, in which 1 is an air cylinder that raises and lowers a helium hood 2, and the helium hood 2 is connected to a helium tank with a regulator via a solenoid valve 4 for helium. It is connected to Pombe 5. Reference numeral 3 denotes an object to be measured, which is communicated with a roughing pump 7 via a roughing pulp 6, and is also communicated with a helium leak detector 10 via a water pulling pulp 8. In addition, in the figure, 9 indicates bent pulp.

In operation, the object to be measured 3 is evacuated with a roughing bong 767 by opening the roughing pulp 6. Next, the air cylinder 1 is lowered to cover the object 3 with the helium hood 2, and then the helium solenoid valve 4 is opened to diffuse helium gas from the helium cylinder 5 into the hood 2. In this state, the rough pulp 6 was closed, the mizuhiki pulp 8 was opened, and the helium leak detector 10 detected the leak t.

(Problems to be Solved by the Invention) When performing a leak test using the conventional helium hood described above, the object to be measured 3 is large and, as shown in FIG. If the helium is dispersed in all directions, the concentration distribution of helium diffusion within the helium hood 2 will not be constant, resulting in diluted areas.For this reason, there will be areas where inspection is impossible or areas where inspection is insufficient. There was a problem that this may occur.

The present invention solves the problems of the above-mentioned prior art, and includes the following: The helium leak test method of the present invention is characterized in that helium gas is targeted and sprayed onto the required inspection part of the object in a hood that covers the object. It is characterized by the fact that a variety of spray nozzles are attached to the inside corresponding to the parts of the object to be inspected that need to be inspected.

(Function) In the helium leak test device of the present invention, when helium gas is sprayed onto the object to be measured from the multi-spray nozzle in the helium hood, the helium gas is intensively diffused into areas where the helium concentration is low in the hood. The helium concentration inside the hood, including the areas requiring inspection, will be sufficient for leak testing.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is an explanatory diagram showing a cross section of the main parts of a helium leak test device showing one embodiment of the present invention, and among the reference numerals shown in this figure, the same reference numerals as those shown in FIG. 6 are used. In Figure 0, which shows the same or similar parts, the vacuum method (external injection type) is used to vacuum the inside of the object to be measured and detect the leakage amount, so for exhausting the object to be measured 13, Roughing bongua and roughing pulp 6 are provided, and leak detection is performed using mizuhiki pulp 8 and helium leak detector 1.
0, and in order to take out the object to be measured 13 after the test, the vent pulp 9 with one end open to the atmosphere is used, which is the same as in the conventional method (Fig. 6), but this example In this case, a helium hood 11 that is lowered by an air cylinder 1 houses an object 13 to be measured, which is large in shape, has a height difference in measurement points, and has measurement points scattered in all directions. , a spray nozzle 1 branched so as to correspond to a plurality of distributed inspection parts 14 of the object to be measured 13.
2 is installed in the helium hood 11 in a manner that communicates with the helium cylinder 5. In the figure, 15 indicates a flow meter, and 16 indicates a Pirani vacuum gauge.

Next, the function and operation of the above embodiment will be explained.

When performing a leak test using the above apparatus, the object to be measured 13 including the object to be inspected section 14 is evacuated by opening the roughing bong f7 and the roughing pulp 6. At this time, a Pirani vacuum gauge 16 is used to measure the internal pressure. Next, the helium hood 11 is lowered by the air cylinder 1 to cover the entire object to be measured 13 including the free inspection section 14. To obtain helium gas, open the helium solenoid valve 4 from the helium cylinder 5.
While checking the flow using a flow meter 15, the helium is diffused into the helium hood 11 through the spray nozzle 12. At this time, if the inspection part 14 of the object to be measured is to be reliably IJ+cutisted, the helium concentration around the inspection part 140 should be kept constant, and the diluted part should be sprayed with helium by aiming from the spray nozzle 12 to carry out the leak test. Ensure sufficient helium concentration. Next, the leak test is performed by closing the rough pulp 6, opening the water pulling pulp 8, and using the He leak detector IO.

At the end of the leak test, the Honkawa pulp 8 is closed, and after a few seconds, the vent pulp 9 is opened, the inside of the object to be measured 13 is returned to atmospheric pressure, the helium hood 11 is raised with the air cylinder l, and the object to be measured 13 is raised. In the above embodiment, a structure in which various spray nozzles installed in a helium hood are formed into a plurality of branch pipe shapes is explained, but the spray nozzle of the present invention is not limited to the above. . For example, FIG. 2 is a side view of a straight line spray nozzle in which a plurality of nozzles 22 are formed at the bottom of a straight tube body 21, and FIG. 4 (a) (b) ri
, a side view and a bottom view of a shower spray nozzle in which a large number of nozzles 42 are formed on the lower surface of a hollow body 41 having a circular shape, 5th
Figures (a) and (b) show a curved pipe 51 shaped like an S-shape.
FIG. 2 is a side view and a bottom view of a figure 8 spray nozzle with a large number of nozzles 52 formed at the bottom of the figure, and the spray nozzle shown in each of these embodiments is used to measure a workpiece having a shape of a cylindrical shape. However, the helium concentration around the area to be inspected can be kept constant and the helium concentration sufficient for leak testing.

It is also possible to form the spray nozzle into a flexible branch pipe shape so that it can be freely deformed according to the shape of the object to be measured, and if necessary, it is also possible to remotely control these deformation operations from the outside. be.

(Effects of the Invention) As explained above, according to the present invention, a wide variety of spray nozzles are installed in the helium hood to target inspection parts.
Even if the object to be measured is difficult to detect, has height differences in the measurement location, or is dispersed in all directions, it can compensate for helium diluted areas.
It is possible to secure a sufficient helium concentration at the required area to be excavated, thereby suppressing variations in the amount of detected leakage, and there is no risk of leakage exceeding the allowable leakage being overlooked. It can also improve helium leak detection ability.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional explanatory view of essential parts of a helium leak test device showing one embodiment of the present invention, and FIGS. 2 to 5 are side and bottom views showing different embodiments of the spray nozzle used in the above device. , FIG. 6 is an explanatory diagram of a conventional helium leak test device, and FIG. 7 is an explanatory diagram of the main parts of a test object in which inspection parts are distributed in all directions. 1-1 air cylinder r, 5--helium pump, 6
--- Rough pulp, 7-- Rough bong, 8-
--Ichimizuhiki pulp, 10-m-leak detector,
11-m-helium hood, 12-m-spray nozzle, 13-m-object to be measured. Figure 2 Figure 3 Atsushi Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. In a method of detecting the total leakage amount of a measured object by creating a vacuum inside the measured object and blowing helium gas from the outside, the measured object is placed in a hood that covers the measured object. A helium leak test method characterized by aiming and spraying helium gas onto the area to be inspected. 2. In a helium leak test device equipped with a helium hood, which creates a vacuum inside the measured object and sprays helium gas from the outside to detect the total leakage amount of the measured object, a variety of spray nozzles are installed inside the helium hood. A helium leak test device characterized by being installed. 3. The helium leak test device according to claim 2, wherein the various spray nozzles are provided corresponding to the required inspection parts in order to target the required inspection parts of the object to be measured.