JPH0130095B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a leak test device for testing the leakage amount of a test object.

(Prior Art) FIG. 1 shows a leak test method called the so-called integral method using a leak test device. In FIG. 1, 1 is a test chamber formed of a closed container, 2 is a test object filled with probe gas 3,
4 is a suction port provided in the test chamber 1; 5 is a detection part of a leak detector with a built-in suction pump;
6 is a measuring section of the leak detector.

Now, if the internal volume of the test chamber 1 after subtracting the volume of the test object 2 is V (CC), the leakage amount of the test object 2 is L (cc/sec), and the standing time is T (sec), then T The concentration A of the probe gas in the space inside the test chamber 1 after standing for a period of time can be expressed as A=L×T/V (1). If the test chamber 1 is filled with the test object 2 filled with probe gas and the concentration A of the probe gas in the test chamber 1 is measured after a certain period of time T by the leak detectors 5 and 6, then from equation (1), the test object leaks. The quantity L can be known.

(Problem to be Solved by the Invention) The advantage of the above method is that even if there is a limit to the maximum sensitivity of the leak detector, it is possible to detect even the smallest amount of leak if left for a long time.
The entire leakage amount of the test object can be inspected at once. However, when the inside of the test chamber is at atmospheric pressure, the concentration of the probe gas in the space inside the test chamber is not necessarily uniform due to the relationship between the diffusion coefficient and specific gravity of the probe gas. This has the drawback that the detected leakage amount varies depending on the suction point during measurement and the leakage point of the test object, leading to non-uniformity in inspection quality. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to realize a leak test device that can eliminate the above-mentioned drawbacks and also detect leak points in a test object, and that is also an object of the present invention.

[Structure of the invention]

(Means for Solving the Problems) The leak test device of the present invention stores a test object filled with a probe gas in a test chamber formed of a sealed container and leaves it there, and detects the probe gas leaking from the test object. In a leak test device that tests the amount of leakage of a test object based on the amount of probe gas accumulated in the test chamber, a plurality of suction ports provided at a plurality of locations in the test chamber, and a plurality of suction ports at each of these suction ports are provided. pipes connected to each other, valves provided in each of these pipes, a valve opening/closing means for sequentially opening these valves for a certain period of time at time intervals, a valve opened and closed by this means, and a valve provided on each of the pipes, a suction pump that suctions the gas in the test chamber;
A leak detector for measuring the probe gas concentration in the gas sucked by the suction pump; a means for comparing the concentration output obtained from the leak detector when each valve is opened; and a means for comparing the concentration output obtained from the leak detector. and an averaging circuit that measures the amount of leakage of the object under test by integrating and averaging.

(Function) In the leak test apparatus of the present invention, a test object filled with probe gas is housed in a test chamber with each valve closed and left for a certain period of time.
After a certain period of time has elapsed, the suction pump is started and each valve is sequentially opened for a certain period of time at time intervals. By comparing the magnitude of the concentration output of the leak detector when each valve is opened, it is possible to know where the leak point is located in the test object. Then, if the concentration output of the leak detector when each valve is open is integrated and averaged by the averaging circuit to obtain the average concentration, this concentration value indicates the average concentration of probe gas in the test chamber. Therefore, the leakage amount L of the test object can be found from A=L×T/V (1).

(Example) Hereinafter, the present invention will be explained in detail based on the example shown in the drawings. FIG. 2 shows a leak test device according to an embodiment of the present invention. In Fig. 2, 1 is a test chamber, 2 is a test object filled with probe gas 3, and S ₁ , S ₂ , S ₃ , and S ₄ are 4 of test chamber 1.
The suction ports provided at the locations, P ₁ , P ₂ , P ₃ , and P ₄ are pipes connected to the respective suction ports, V ₁ , V ₂ ,
V ₃ and V ₄ are valves provided in the pipes P ₁ , P ₂ , P ₃ and P ₄ , respectively. In addition, the pipes from each valve are collected into one pipe and connected to the leak detector LD via the suction pump PM. And each valve V _1
-V4 are sequentially opened for a certain period of time at predetermined time intervals, as shown in FIG. 3a, by a valve opening/closing means (not shown). In Figure 2, 1
0 is an averaging circuit that integrates and averages the concentration output obtained from the leak detector LD when each valve V ₁ to _{V 4} is sequentially opened, calculates the average concentration of the probe gas in the test chamber 1, and calculates the average concentration of the probe gas in the test chamber 1 based on this. Determine the leakage amount of the test object.

In the leak test apparatus according to the embodiment of the present invention configured as described above, the test object 2 filled with the probe gas 3 is housed in the test chamber 1 with each valve V ₁ to _{V 4} closed, and Leave it for a while.
After a certain period of time has elapsed, _the suction pump PM is started, and as shown in _FIG . Open the valve. As a result, the gas near the suction ports S ₁ , S ₂ , S ₃ , and S ₄ is sequentially sent to the leak detector LD.

Therefore, the magnitude of the concentration output of the leak detector LD when each valve V ₁ to _{V 4} is opened is determined by means not shown (or by an inspector).
By comparing, it is possible to know where the leak point is located in the test object 2. That is, the third
If the concentration output of the leak detector LD drops as shown in FIG. b, it can be seen that the leak point is near the suction port _S4 . Of course, the more suction ports there are, the more accurately the leak point can be determined.

In addition, when each valve V ₁ to _{V 4} is opened, the concentration output of the leak detector LD is determined by the averaging circuit 1.
The average concentration is calculated by integrating and averaging in the averaging circuit 10, and the leakage amount of the test object 1 is calculated based on A=L×T/V (1). L is required.

〔Effect of the invention〕

As described in detail above, according to the present invention, in a leak test using the integral method, it is possible not only to solve the problem of measurement errors caused by non-uniformity of the probe gas concentration in the test chamber, but also The leak point of the test object can be found by comparing the concentration output of the leak detector for each sampling by sampling at a certain time interval from We can also provide a leak test device that can perform

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a conventional example of a leak test device using the integral method, FIG. 2 is a system diagram showing a leak test device according to an embodiment of the present invention, and FIGS. 3 is a graph showing a time chart of a valve opening operation and a leak detector output at the time of each valve opening operation. 1... Test chamber, 2... Test object, 3...
...Probe gas, 10...Averaging circuit, S ₁ , S ₂ ,
S ₃ , S ₄ ... Suction port, P ₁ , P ₂ , P ₃ , P ₄ ... Piping,
V ₁ , V ₂ , V ₃ , V ₄ ... Valve, PM ... Suction pump,
LD...Leak detector.

Claims (1)

[Claims] 1. A test object filled with probe gas is stored in a test chamber formed of a sealed container and left to stand, probe gas leaking from the test object is accumulated in the test chamber, and the amount of probe gas accumulated is A leak test device for inspecting the amount of leakage of a test object includes a plurality of suction ports provided at a plurality of locations in the test chamber, pipes connected to each of these suction ports, and valves provided respectively to each of these pipes. a valve opening/closing means that sequentially opens these valves for a certain period of time at time intervals; a suction pump that suctions gas in the test chamber through the valves opened and closed by this means and the piping; and this suction pump. a leak detector for measuring the probe gas concentration in the gas sucked by the leak detector; and a means for comparing the magnitude of the concentration output obtained from the leak detector when each valve is opened;
A leak test device comprising: an averaging circuit that integrates and averages the concentration output obtained from the leak detector to measure the leak amount of the test object.