JPH0587770B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a leak detector that tests for leaks in a test object using a probe gas.

B. Prior Art Helium leak detectors using helium gas have been known. This leak detector evacuates the test object, sprays helium gas from the outside with a probe gun, measures the amount of helium gas leaking into the test object with a mass spectrometer, and displays the leak amount indicator. It is to be displayed. That is, this leak detector converts the detected leak amount into an electrical signal to drive an analog pointer or a digital display to display the instantaneous value of the leak amount in real time.

C. Problems to be Solved by the Invention However, with this leak detector, the background fluctuates and it is virtually impossible to calibrate the display value to zero, so the operator must calibrate the display value based on the background before testing. is memorized and the display on the display after helium gas is sprayed is compared with the value before helium gas is sprayed to determine whether there is a leak. Therefore, it is difficult to accurately determine the presence or absence of a leak.

A technical object of the present invention is to display the background level of leakage amount and the measurement in an easy to compare manner.

D Means for Solving the Problems To explain with reference to FIG. 1 showing an embodiment, the present invention detects the leakage of the sprayed probe gas from the test object and outputs an electric signal according to the amount of leakage. The present invention is applied to a leak detector that includes a detector 2 and a display 12 that displays the amount of leakage based on the detection output of the detector 2.

The above-mentioned technical problem is solved by the following configuration.

A gas flow meter 13 that detects the flow rate of the blown probe gas and outputs an electric signal according to the flow rate, a detector 2, and a gas flow meter 1.
A storage device 10M captures and stores the detection output of No. 3 at a predetermined sampling period, and a display device 12 stores the data stored in the storage device 10M so that the leakage amount and the time change in the probe gas flow rate are displayed on the display device 12.
A control circuit 11 is provided.

E. Effect The leakage amount and the time change in the probe gas flow rate stored in the memory 10M are displayed as images on the display 12. The operator can easily compare the background level of the leak amount before starting the test with the level of the leak amount after spraying the probe gas from the display screen. Furthermore, the level of the amount of probe gas sprayed and the amount of leak can be compared, making it easy to determine whether there is a leak.

Note that in the above sections D and E explaining the configuration of the present invention, figures of embodiments are used in order to make the present invention easier to understand, but the present invention is not limited to the embodiments.

F Example One example will be described with reference to FIGS. 1 and 2.

In FIG. 1, an analysis tube 1 detects helium ions in a evacuated test object with an ion collector (detector) 2 and outputs an electric signal in accordance with the detected helium ions. The DC amplifier 3 amplifies the electrical signal from the ion collector 2. This DC amplifier 3 is capable of range switching by performing gain adjustment by a range switching mechanism 4. A/D converter 5 converts the output of DC amplifier 3 into a digital value. The automatic range changeover command mechanism 6 controls the A/D converter 5 when the range changeover switch 7 is set to automatic.
A range setting signal based on the output value of is sent to the range switching mechanism 4 to automatically switch the range of the DC amplifier 3. When the range selector switch 7 is switched to the manual side, the range of the DC amplifier 3 is switched by a signal from the manual range measuring device 8.

The probe gas flow meter 13 detects the flow rate of helium gas blown onto the test object from a probe gas (not shown), and outputs a signal corresponding to the flow rate. This detection signal also applies to the A/D converter 1.
4 is considered a digital value.

The control circuit 10 has a memory 10M, which captures the output values of the A/D converters 5 and 14 at a predetermined sampling period, and stores the data at each point in time as instantaneous values of the leak amount and the probe gas flow rate.
to be memorized. The memory 10M has a memory capacity for one screen of a dot display 12, which will be described later, and the sampling period is varied by a sweep time setting device 9. Therefore, if the sampling time is shortened, the time axis within one screen of the dot display 12 will be shortened, and if the sampling time is lengthened, the time axis will be lengthened. For tests with poor responsiveness, the sampling period is lengthened, and for tests with good responsiveness, the sampling period is shortened.

The display drive circuit 11 creates a display drive signal based on the display data sent from the memory 10M and drives the subsequent dot display 12.

The dot display 12 is a well-known dot matrix display such as a liquid crystal type or a light emitting diode type.
The display data is sequentially sent from the memory 10M to the display drive circuit 11 so that the screen display changes along the time axis at each sampling period. Dot indicator 12 shown in FIG.
, the horizontal axis of the screen is the time axis, the vertical axis shows the leakage amount and the gas spraying amount, the solid line A shows the leakage amount, and the broken line B shows the gas spraying amount. There is a digital display section 12D at the top right of the screen, and the latest data on the amount of leakage is digitally displayed.

Now, when helium gas is sprayed from the probe gas at time TO, the device shown in FIG. is stored at a predetermined sampling period. At that time, the amount of helium gas leaking into the test object is detected by the ion collector 2 and stored in the memory 10M via the A/D converter 5 at a predetermined sampling period.

The screen of the dot display 12 after a time _t1 has elapsed from the time TO becomes as shown in FIG. 2a. In other words, when helium gas is blown at time TO, the output waveform of the helium gas flow meter 13 is shown by the broken line B.
After a certain time t ₂ has passed from time TO,
A solid line A shows a waveform when the ion collector 2 detects helium gas leaking into the test object. Therefore, the time when helium gas was sprayed
The difference between the background level at TO and the leakage level when the ion collector 2 detects helium gas after time T1 is clearly visible on the screen, and the presence or absence of leakage in the test object can be accurately determined. Additionally, the relationship between the flow rate of the blown helium gas and the amount of leakage can be quantitatively compared, making it easy to understand whether the test object is acceptable or not. In addition,
FIG. 2b shows the screen display when time t3 has further elapsed from time T1.

Further, as shown in FIG. 3, the background of the solid line A at the time TO when helium gas was blown is stored as the zero level of the ion collector output, and the level is shown as a broken line C on the dot display 12. Good too. In addition, the display section 12D
If a value L based on the zero level is displayed as the leak amount display value, a more accurate test result can be obtained.

Furthermore, if the level that is the pass/fail judgment standard for the test object can be entered by key-in, and the key-in level is displayed as a dashed line D on the screen of the dot display 12 as shown in FIG. 4, pass/fail judgment can be made. It becomes easier. In this case, as explained in Fig. 3, the background at time TO when helium gas is blown is taken as the zero level of the ion collector output.
If the pass/fail determination level D is corrected by the amount of the background and displayed as indicated by a dashed-dotted line E, even more accurate testing becomes possible.

Furthermore, as shown in FIG. 5, before the test, the standard leak 22 is connected to the test object TP via the valve 21, and the valve 21 is opened to force helium gas from the standard leak 22 to the test object TP. The gas flow rate from the standard leak 22 and the response waveform of the ion collector 2 at that time are detected.
Then, in response to the start of the test, the waveform F of the gas flow meter and the ion collector 2 are adjusted as shown in FIG.
The response waveform G is displayed on the dot display 12 in a superimposed manner together with the output waveform A of the ion collector 2 during the test. In this way, it is only necessary to perform the test for the time t ₃ expected from the rise time of the standard response waveform G, and there is no need to unnecessarily lengthen the test time to accurately determine the presence or absence of a leak. Efficient testing can be performed.

The present invention can also be applied to leak detectors using other types of probe gases than helium gas. Furthermore, the systems of the display and probe gas detector are not limited to the embodiments.

G Effects of the Invention According to the present invention, since the spray flow rate of the probe gas and the time change of the leakage amount are simultaneously displayed on the display, it is easy to judge whether there is a leak or not, and the pass/fail judgment of the test object is made easier. It becomes easier.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the entire leak detector, Figure 2 is a diagram showing its display screen, Figures 3 and 4 are diagrams showing other examples of display screens, and Figure 5 is a response due to standard leak. FIG. 6 is a diagram illustrating the display screen for measuring the performance. 1... Analysis tube, 2... Ion collector, 3...
DC amplifier, 5, 14...A/D converter, 9
...Sweep time setter, 10...Control circuit, 10M
...Memory, 12...Dot display, 13...Gas flow meter.

Claims (1)

[Claims] 1 Equipped with a detector that detects the leakage of the sprayed probe gas from the test object and outputs an electrical signal according to the amount of leakage, and a display that displays the amount of leakage based on the detection output of this detector. The cooli detector includes a gas flow meter that detects the flow rate of the blown probe gas and outputs an electric signal according to the flow rate, and a memory that captures and stores the detection outputs of the detector and the gas flow meter at a predetermined sampling period. A leak detector comprising: a control circuit that sends data stored in the memory device to the display device so that the time change in leakage amount and probe gas flow rate is displayed on the display device.