Method and device for detecting leaks
AssigneeInficon GmbH
InventorsJörn Liebich, Randolf Rolff, Ralf Kilian
Life of this patent
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Abstract
In leak detection, the signal generated by a test gas is superposed by interferences which fade as the vacuum generation in a container proceeds. Depending on the negative slope of the volume signal (MS), a lower indication limit (AG) is calculated. Upon activation of a zero function, the volume signal (MS) is not reduced to zero but only to the level of the indication limit (AG). Any exceeding of the indication limit is identified as a leak. Thus, the maximum sensitivity of the leak detection is guaranteed at any time.
Claims10
A leak detection method, said method comprising the steps of:
- drawing off gas;
- detecting test gas in the gas drawn off, and generating a volume signal (MS) corresponding to a measured leak rate (Q);
- treating the volume signal (MS) such that the volume signal is reduced when a zero signal is generated;
- calculating signal dithering
- (
- ⅆ
- Q
- ⅆ
- t
- )
- of the volume signal;
- determining a lower indication limit (AG) from the calculated signal dithering;
- and
- indicating a leak only if the volume signal (MS) exceeds the lower indication limit (AG).
A leak detection method, said method comprising the following steps:
- drawing off gas;
- detecting test gas in the gas drawn off, and generating a volume signal (MS) corresponding to the measured leak rate (Q);
- treating the volume signal (MS) such that the volume signal is reduced when a zero signal is generated;
- calculating the signal dithering (D) of the volume signal (MS);
- presetting a trigger value (T);
- and
- enabling the zero function only if the signal dithering (D) of the volume signal (MS) is less than the trigger value (T).
A leak detector comprising a vacuum connection, a high vacuum pump device connected with the vacuum connection, a test gas sensor, a microcomputer and a control device including a display device and an input device for a zero signal intended to reduce the volume signal (MS) supplied by the test gas sensor, wherein a differential circuit is provided that, from the volume signal, generates a signal dithering value, from which a lower indication limit (AG) is calculated, and wherein the display device only indicates a leak rate differing from the indication limit if the reduced volume signal (MS) exceeds the indication limit (AG).
A leak detector comprising a vacuum connection, a high vacuum pump device connected with the vacuum connection, a test gas sensor, a microcomputer and a control device including a display device and an input device for a zero signal intended to reduce the volume signal (MS) supplied by the test gas sensor, a differential circuit that generates a signal dithering value (D) from the volume signal (MS), a logic means for evaluating the signal dithering (D) and disables or enables a disabling means for the zero signal, and a trigger input supplies a trigger value (T) indicating from which value on the leak rate should be measurable, the disabling means disabling the zero signal below said value.
Dependencies are inferred from the claim text.