Sniffer leak detector with distance-dependent control of the carrier gas flow

Abstract

A sniffer leak detector is provided herein, including a sniffer probe and a vacuum pump which are connected to each other by a gas flow path, a gas analyzer arranged along the gas flow path and analyzes the gas taken in by the vacuum pump through the sniffer probe. The sniffer leak detector further includes a distance sensor that detects the distance between the sniffer probe and the test object, and a control is linked to the distance sensor. The control is designed to vary the carrier gas flow transported along the gas flow path, depending on the measured distance.

Claims

1. A sniffer leak detector comprising a sniffer probe and a vacuum pump connected to each other via a gas flow path, and a gas analyzer is arranged along the gas flow path for analyzing the gas drawn in by the vacuum pump via the sniffer probe, a distance sensor configured to detect the distance between the sniffer probe and a test object, and a control is connected to the distance sensor, and is configured to vary a carrier gas flow conveyed along the gas flow path depending on the distance measured; wherein the control influences a flow rate of the vacuum pump by adjusting a speed of the vacuum pump and/or influences a flow resistance of a throttle arranged in the gas flow path.

2. The sniffer leak detector of claim 1, wherein the control influences the flow rate of the vacuum pump.

3. The sniffer leak detector of claim 1, wherein the control influences the flow resistance of a throttle arranged in the gas flow path.

4. The sniffer leak detector of claim 1, wherein the gas analyzer is arranged along the gas flow path between the sniffer probe and the vacuum pump.

5. The sniffer leak detector of claim 1, wherein the gas analyzer is arranged in a second gas flow path connected to the sniffer probe, and the gas flow of the second gas flow path is not influenced by the control.

6. The sniffer leak detector of claim 1, wherein a speed sensor is configured to measure a relative speed of the sniffer probe with respect to the test object, the control is further configured to control the gas flow depending on the speed measured.

7. A method for sniffer leak detection with a sniffer leak detector according to claim 1, comprising: measuring the distance between the distance sensor and a test object to be checked for a leak; guiding the carrier gas flow along the gas flow path to be drawn in by the sniffer probe; and adjusting the carrier gas flow by the control depending on the distance measured.

8. The method of claim 7, further comprising monitoring the distance measured for a predefined period, and increasing the carrier gas flow if the distance increases and/or decreasing the carrier gas flow if the distance decreases.

9. The method of claim 7, displaying the amount of test gas detected, taking into account the measured distance and/or taking into account the adjusted carrier gas flow.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Three embodiments of the disclosure will be explained in detail hereunder with reference to the Figures. In the Figures:

(2) FIG. 1 shows a schematic illustration of the first embodiment,

(3) FIG. 2 shows a schematic illustration of the second embodiment,

(4) FIG. 3 shows a schematic illustration of the third embodiment, and

(5) FIG. 4 shows a diagram illustrating the relationship between distance, speed and gas flow.

DESCRIPTION OF THE INVENTION

(6) First, the common features of the embodiments will be explained below.

(7) The sniffer leak detector 10 comprises a sniffer probe 12, the sniffing tip 14 of which is provided with an intake opening 16 for drawing in a gas flow. The rear end of the sniffer probe 12 is connected to a first vacuum pump 20 via a first gas flow path 18. The first vacuum pump 20 is configured to generate a gas pressure that is reduced relative to the surroundings 22 of the sniffer probe 12. The vacuum pump 20 is designed as a gas conveyor pump and draws gas through the take-in opening 16 from the surroundings 22 and conveys the same along the gas flow path 18.

(8) The sniffer probe 12 is provided with a distance sensor 24 arranged at the sniffing tip 14 in the region of the take-in opening 16. The distance sensor 24 is configured to detect the distance 26 from a surface 28 of a test object 30 in the vicinity of which the sniffer probe 12 is positioned to draw in test gas 34 escaping from a possible leak 32.

(9) Gas drawn in by the sniffer probe 12 through the take-in opening 16 is supplied to a gas analyzer 36, which may e.g. be a mass spectrometer. The gas analyzer 36 is configured to detect test gas 34.

(10) The distance 26 measured by the distance sensor 24 is transmitted to a control 40 via an electronic line 38. The control 40 may e.g. be a microcontroller or a computer. The control 40 is configured to change and adjust the gas flow conveyed along the first gas flow path 18 in dependence on the distance 26 measured. This may be effected in the following ways via an electric line 42:

(11) The flow resistance of an adjustable throttle 44 arranged along the first gas flow path 18 is adjusted or changed by the control 40. If, as illustrated in FIG. 1, the gas analyzer 36 is arranged along the first gas flow path 18, the throttle 44 can be arranged between the sniffer probe 12 and the gas analyzer 36 and/or (as illustrate in broken lines in FIG. 1) between the gas analyzer 36 and the vacuum pump 20.

(12) Alternatively or complementarily, the control 40 can adjust or vary the flow rate of the pump 20 via the line 42, e.g. by the control 40 adjusting the speed of the pump 20.

(13) The differences between the embodiments will be explained below.

(14) In FIG. 1, the gas analyzer 36 is arranged along the first gas flow path 18.

(15) In the second embodiment illustrated in FIG. 2 and in the third embodiment illustrated in FIG. 3, the gas analyzer 36 is arranged along a second gas flow path 46 different from the first gas flow path 18. The second gas flow path 46 connects the sniffer probe 12 to a vacuum pump 20 different from the first vacuum pump 20. The underlying idea is that the flow along the first gas flow path 18, adjusted by the control 40, at least indirectly also influences the flow conveyed along the second gas flow path 46 and the amount of gas conveyed along the second gas flow path 46, respectively.

(16) In the second embodiment illustrated in FIG. 2 and in the third embodiment illustrated in FIG. 3, the control 40 can adjust or vary the flow resistance by means of a throttle corresponding to the throttle 44 of the first embodiment. As an alternative to the throttle 44, the first gas flow path 18 can comprise a valve 50 which, for purposes of illustration, is shown adjacent the throttle 44 in FIGS. 2 and 3 and which, similar to the throttle 44, can be actuated by the control 40 via the line 42. In the closed state of the valve 50, no gas is conveyed along the first gas flow path 18 so that all gas drawn in by the sniffer probe is supplied to the gas analyzer 36 via the second gas flow path 45. In the open state of the valve 50, only a part of the gas drawn in by the sniffer probe 12 reaches gas analyzer 36 via the second gas flow path 46, while another part of the gas drawn in is guided along the first gas flow path 18.

(17) Alternatively or complementarily to the throttle 44 or the valve 50, the control 40 may, similar to the first embodiment, also act directly on the flow rate of the first vacuum pump 20 and may e.g. switch the same on or off. Similar to a closed valve 50, in the switched-off state of the first vacuum pump 20, the entire gas flow drawn in by the sniffer probe 12 is supplied to the gas analyzer 36 via the second gas flow path. Similar to an open valve 50, in the switched-on state of the pump 20, a part of the gas drawn in is conveyed via the first gas flow path 18, while another part is supplied to the gas analyzer 36 via the second gas flow path 46.

(18) The third embodiment differs from the second embodiment in a speed sensor 52 separate from the distance sensor 24 and also arranged at the sniffing tip 14, the speed sensor being configured to measure the relative speed 54 of the sniffing tip 14 with respect to the surface 28. The speed measured is also transmitted to the control 40 via a line not illustrated in FIG. 3. The control 40 is configured to adjust or vary the gas flow guides along the first gas flow path 18 in the manners described above.

(19) FIG. 4 shows the relationship between the distance 26, the relative speed 54 and the flow 56 along the first gas flow path 18 which is to be adjusted. The greater the distance 26 and/or the higher the speed 54, the lower the flow 56 has to be set in order to detect the same amount of test gas and to leave the test gas detection limit unchanged for a detection of a leak 32.