Method for checking the leak-tightness of an object to be tested, spray device and leak detector corresponding thereto

Abstract

The invention relates to a method for checking the leak-tightness of an object to be tested (A) by spraying tracer gas, the method being configured to be implemented at least in part by a leak detector (200) and a spray device (100) for spraying tracer gas, the spray device comprising a duct (101), the method comprising the following steps: - detecting a predetermined distance between the spray device and the object to be tested (A) by means of a distance sensor (103) at an outlet (101b) of the duct; and - when the predetermined distance is detected, controlling the spraying, for a predefined duration, of a predefined stream of tracer gas in the direction of the object to be tested (A), the interior of which is connected to the leak detector. The invention also relates to a spray device and a leak detector for implementing such a method.

Description

Method for checking the leak-tightness of an object to be tested, including the corresponding spraying device and leak detector.

[0001] The present invention relates to a tracer gas spraying device for leak detection, and a leak detector for checking the tightness of an object to be tested using tracer gas. The invention may also relate to a leak detection assembly comprising such a spraying device and such a leak detector. Technical background

[0002] A well-known method for checking the watertightness of an object involves performing a tracer gas "spray" test. This method relies on detecting the passage of the tracer gas, usually helium, through any leaks in the object being tested.

[0003] The tracer gas is sprayed onto the object to be tested, for example, using a spray gun, with the object's interior volume connected to a leak detector. Leak detection is generally carried out by moving the nozzle of the spray gun around the object, particularly in areas likely to have weak seals, such as around gaskets.

[0004] One challenge is spraying a sufficiently large quantity of tracer gas in the right place to detect a leak without missing one or more leaks. For example, with this method, tracer gas can sometimes be sprayed when the spray gun is too far from the object being tested. On the one hand, the leak may go undetected, and on the other hand, significant concentrations of tracer gas can be released around the object, potentially polluting the surrounding environment. The tracer gas present around the object can interfere with the measurements. It is then necessary to wait for the background noise to decrease, which can be lengthy and therefore costly, and is detrimental to the environment. Another drawback is that this excessive consumption of tracer gas, particularly helium, is expensive.

[0005] One of the aims of the present invention is to propose a method for checking the leak tightness of an object to be tested by spraying tracer gas, a spraying device for leak detection, a leak detector and a detection assembly which resolve at least in part the aforementioned drawbacks.

[0006] To this end, the invention relates to a method for checking the leak-tightness of an object to be tested by spraying a tracer gas, configured to be implemented at least in part by a leak detector and by means of a tracer gas spraying device for leak detection, comprising a conduit with an inlet and an outlet. According to the invention, said method comprises the following steps: detection of a predetermined distance between the spraying device and the object to be tested, by means of a distance sensor arranged at the outlet of the spraying device conduit, and when the predetermined distance is detected, triggering the spraying of a predefined flow of tracer gas, for a predetermined duration, towards the object to be tested by means of the tracer gas spraying device, the internal volume of the object to be tested being fluidly connected to the leak detector.

[0007] Thus, when the spray device is positioned at the appropriate distance (predetermined in advance) from the part to be tested, the required quantity of tracer gas, such as helium, can be automatically sprayed at a predetermined rate or flow. The spraying is therefore controlled in terms of both flow rate and duration.

[0008] The invention also relates to a tracer gas spraying device for leak detection, configured to implement at least in part a method for checking the tightness of an object to be tested by spraying tracer gas as defined above, the spraying device comprising a conduit having an inlet and an outlet, the spraying device having a distance sensor arranged at the outlet of the conduit and configured to detect a predetermined distance between the spraying device and the object to be tested, and the spraying device being configured to spray a predetermined flow of tracer gas, for a predetermined duration, in the direction of the object to be tested, when the predetermined distance is detected (and only when the predetermined distance is detected).

[0009] The invention further relates to a leak detector for checking the tightness of an object to be tested by tracer gas, the leak detector being configured to be fluidly connected to an internal volume of the object to be tested and configured to implement at least in part a method of checking the tightness of an object to be tested by spraying tracer gas as defined above.

[0010] The said detection method and / or the spraying device and / or the leak detector may further include one or more of the following characteristics described below, taken separately or in combination.

[0011] The spraying device can remain stationary during spraying.

[0012] Alternatively, during spraying, the spraying device can be moved around the object to be tested.

[0013] The distance sensor can continuously measure the distance between the spraying device and the object to be tested, including during the predefined spraying time.

[0014] The spraying can continue until the end of the predefined time even if the measured distance differs from the predetermined distance.

[0015] The said process may include a step of verifying the active state of the leak detector.

[0016] The leak detector can be fluidically isolated or made fluidically connected to the internal volume of the object to be tested by means of at least one valve configured to take a closed or open position.

[0017] The said process may include a step of verifying the open or closed position of at least one valve.

[0018] If at least one valve is in the open position, the spraying can be controlled.

[0019] If at least one valve is in the closed position, the command to spray the predefined quantity of tracer gas towards the object to be tested may be prohibited.

[0020] The said process may include a step of emitting an alert signal to warn a user when spraying is prohibited.

[0021] The step of controlling the spraying of the predefined tracer gas flow may include the emission of at least one warning signal to a user requiring manual actuation of the spraying device.

[0022] The step of controlling the spraying of the predefined tracer gas flow can trigger an automatic piloting of the spraying device.

[0023] The control step of the predefined flow of tracer gas spraying can be implemented by a spray device processing unit connected to the distance sensor.

[0024] The said method may include at least one communication step between a communication module of the spraying device and a control unit of the leak detector, during which at least one distance data detected by means of the distance sensor is communicated to the control unit of the leak detector.

[0025] When the predetermined distance is detected, the leak detector control unit can activate a leak test including the step of controlling the spraying of the predetermined flow of tracer gas.

[0026] A nozzle can be fitted to the outlet of the duct. The distance sensor can be fitted to one end of the nozzle.

[0027] The communication module of the sprinkler system can be wireless.

[0028] The communication module of the spraying device can be configured to exchange at least one distance data detected by means of the distance sensor with a leak detector control unit via communication, including wirelessly.

[0029] The distance sensor can be chosen from a capacitive sensor or an inductive sensor.

[0030] The spraying device may include a processing unit configured to receive an output signal from the distance sensor and to control the spraying of the predefined flow of tracer gas according to the output signal.

[0031] The leak detector may include a control unit.

[0032] The leak detector control unit can be configured to receive and analyze at least one distance data point detected by a distance sensor of a spray device relative to the object being tested. The distance data point can be an output signal from the distance sensor. The output signal may have undergone signal processing, particularly within the spray device's processing unit.

[0033] The leak detector control unit can be configured to identify when a predetermined distance is detected based on the output signal from the distance sensor.

[0034] The leak detector control unit can be configured to, when the predetermined distance is detected (and only when the predetermined distance is detected), command a spray of a predefined flow of tracer gas, for a predefined duration, towards the object to be tested by means of the tracer gas spraying device by emitting a control signal to the spraying device and / or at least one element of the leak detector, for example, to start a leak test.

[0035] The leak detector control unit can be configured to detect the open or closed position of at least one valve for isolating or connecting fluid between the leak detector and the internal volume of the object under test. The leak detector control unit can be configured to issue an alert signal when at least one valve is in the closed position.

[0036] The invention further relates to a leak detection assembly for testing the tightness of at least one object to be tested by spraying tracer gas comprising at least one spraying device and a leak detector as defined above.

[0037] The detection system may include a tracer gas source fluidly connected to an inlet of a duct of the spraying device.

[0038] Other advantages and features of the invention will become clearer upon reading the following description, given by way of illustrative and non-limiting example, and the accompanying drawings, among which:

[0039] is a very schematic representation of a leak detection system comprising a tracer gas spray gun and a leak detector for checking the tightness of an object to be tested by tracer gas.

[0040] shows a schematic view of an example of a leak detector for checking the tightness of an object to be tested by tracer gas.

[0041] is a simplified grarcet representing steps in a process of checking the leak tightness of an object to be tested by spraying tracer gas.

[0042] In these figures, identical elements bear the same reference numbers.

[0043] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments can also be combined or interchanged to provide other embodiments, without departing from the scope of the invention as defined by the claims. Detailed description

[0044] With reference to the present invention, the invention relates to a leak detection assembly 1 for checking the tightness of at least one test object A by spraying tracer gas. A "test object" A corresponds to an object whose tightness is to be checked.

[0045] The invention also relates to a method for checking the leak-tightness of an object under test by spraying a tracer gas. The use of tracer gas makes it possible to detect very small leaks, for example, flow rates of up to 10 -8 mbar.Ls -1 (10 -9 Pa.m 3 .s -1 Helium or hydrogen is generally used as a tracer gas because these gases pass through small leaks more easily than other gases, due to the small size of their molecule and their high speed of movement.

[0046] Leak detection kit

[0047] The leak detection assembly 1 comprises at least one tracer gas spray device 100 for the object under test A, and a leak detector 200 for checking the tightness of the object under test A using tracer gas. The detection assembly 1 may include a tracer gas source 300 fluidly connected to the spray device 100.

[0048] The 100 spraying device, for example, is made in the form of a spray gun.

[0049] The spray device 100 includes a conduit 101 extending between an inlet 101a and an outlet 101b. This conduit 101 may extend inside a housing or shell of the spray device 100.

[0050] The inlet 101a of the conduit 101 can be connected to the tracer gas source 300, such as a tracer gas cylinder or a refillable tracer gas cartridge. A valve 301, optionally controllable, can be placed between the tracer gas source 300 and the inlet 101a of the conduit 101 and the spray device 100.

[0051] In operation, a tracer gas jet can be projected via outlet 101b.

[0052] The spraying device 100 also includes a distance sensor 103, arranged at the outlet 101b of the conduit 101.

[0053] A nozzle 105 can be fitted to the outlet 101b of the conduit 101, allowing the tracer gas jet to be projected or blown. The nozzle 105 may, for example, include a long, thin metal tube to facilitate access to small search areas. The distance sensor 103 can then be fitted to one end of the nozzle 105.

[0054] The distance sensor 103 is configured to detect when the spray device 100 is at a predetermined distance from the object to be tested A. The spray device 100 is configured to spray a predetermined flow of tracer gas, for a predetermined duration, in the direction of the object to be tested A, when the predetermined distance is detected.

[0055] This predetermined distance can be less than or equal to 10 cm, or even zero. The distance sensor 103 can be configured to detect the presence or absence of the object under test A within a given proximity range; in this case, the sensor 103 can also be called a proximity sensor. Alternatively, the distance sensor 103 can be configured to detect contact with the object under test A (which corresponds to a predetermined distance of zero); in this case, the sensor 103 can also be called a contact sensor.

[0056] The 103 distance sensor is chosen for example from a capacitive sensor, or an inductive sensor.

[0057] As an example, the distance sensor 103 can be a capacitive sensor comprising at least one electrode made of electrically conductive material or having an electrically conductive coating, such as aluminum or copper. The capacitive sensor can operate by measuring a change in a capacitive field between a face of the distance sensor 103 and the object under test A. The object under test A can be made of an electrically conductive material, such as a metallic material. Conversely, it can be made of any other non-metallic and non-conductive material. No special coating or material on the object under test A is necessary for the capacitive sensor to detect distance. When the object under test A moves closer to the face of the distance sensor 103, the capacitive field changes.This change can be converted into a digital or analog output to indicate the approach / presence of the object to be tested A at the predetermined distance or within the given proximity range.

[0058] In another example, the distance sensor 103 can be an inductive sensor comprising a sensor head equipped with at least one electromagnetic coil. During operation, when the inductive sensor approaches the object under test A, which includes at least some metallic material, the impedance of the coil changes. The variation in this impedance depends on the distance between the distance sensor 103 and the metallic object under test A, or the metallic part of the object under test A.

[0059] The spray device 100 may also include a comparator connected to the distance sensor 103. The comparator may, for example, consist of an electronic circuit. The comparator can be configured to compare the measurement from the distance sensor 103 with a predetermined distance, and to trigger or not a tracer gas spray based on the comparison result.

[0060] The spraying device 100 may also include a gripping element, such as a handle or a trigger 107, which can be grasped and manipulated by a user to trigger the projection of the tracer gas jet.

[0061] Furthermore, the spraying device 100 may include a processing unit 109, shown schematically in the figure. The processing unit 109 may include one or more processing means such as one or more controllers, microcontrollers, computers, or electronic boards, comprising memories and programs adapted to drive or control the operation of one or more components of the spraying device 100.

[0062] This processing unit 109 can be received inside the housing of the spraying device 100.

[0063] The distance sensor 103 can be configured to provide an output signal to the processing unit 109. This output signal can trigger the spraying of tracer gas. To achieve this, the distance sensor 103 may include an electronic circuit board connected to the processing unit 109. The processing unit 109 may include a comparator. Furthermore, the processing unit 109 can be configured to control the spraying of tracer gas for a predefined duration based on the output signal.

[0064] The spray device 100 may include a communication module, such as a wireless communication module, configured to exchange, particularly via wireless communication, one or more data points or parameters with the leak detector 200, specifically a control unit 201 of the latter. The communication module, particularly the wireless one, may notably transmit at least one distance data point detected by means of the distance sensor 103, or the output signal of the distance sensor 103.

[0065] The communication module, in particular wireless, for example of type WIFI, Bluetooth or other, can be received in the housing of the spraying device 100. The processing unit 109 can include such a communication module, in particular wireless.

[0066] The communication module can also receive data representative of the state of the leak detector 200. The information on the state of the leak detector 200, namely whether it is active / in the process of or ready to perform a measurement, allows, for example, a user who cannot directly view the leak detector 200, to ensure that it is indeed active before triggering a manual spraying, for example.

[0067] The communication module can, depending on an option, receive a spray command from the leak detector 200 to automatically control, for example, the spray device 100.

[0068] Furthermore, the 100 sprinkler system can be equipped with an information medium, for example audio and / or visual.

[0069] The information medium may include, for example, a screen, such as a digital or liquid crystal display (LCD), arranged to be visible to the user. The information medium may also include at least one indicator light, such as a light-emitting diode (LED).

[0070] As an alternative or in addition, the information medium may include a loudspeaker.

[0071] The spraying device 100 may also include at least one haptic or vibratory actuator, carried by the housing, for example at the trigger 107, allowing haptic feedback, such as a vibration, to the user.

[0072] The information carrier and / or the haptic actuator can be used to signal the user to trigger a spray by activating trigger 107 for example, or other warning signals.

[0073] Regarding the leak detector 200, an example of implementation is shown schematically on the.

[0074] The control unit 201 of the leak detector 200 may include one or more processing means such as one or more controllers or microcontrollers or computers or electronic card, comprising memories and programs adapted to drive or control the operation of one or more components of the leak detector 200.

[0075] The control unit 201 can be configured to receive and analyze at least one data point, in particular at least one distance data point detected by means of the distance sensor 103 of the spray device 100 with respect to the object to be tested A. This can be the output signal of the distance sensor 103, or a signal emitted after signal processing within the processing unit 109 of the spray device 100.

[0076] The control unit 201 may include a communication module, including wireless, for example of type WIFI, Bluetooth or other, configured to exchange one or more data with the spraying device 100, including the communication module of the latter.

[0077] The control unit 201 can be configured to identify when a predetermined distance is detected based on the output signal from the distance sensor 103, and command the spraying of tracer gas for the predetermined duration.

[0078] The control unit 201 can, when a predetermined distance is detected, be configured to trigger the spraying of a predefined flow of tracer gas. For this purpose, the control unit 201 can send a control signal to the spraying device 100 and / or at least one element of the leak detector 200, for example, to initiate a leak test.

[0079] For example, the leak detector 200 may include at least one secondary vacuum pump such as a turbomolecular pump 202, at least one primary pump 203, at least one gas analyzer 205, and a set of fluid lines. The control unit 201 can be connected to the pumps 202, 203 and the gas analyzer 205 to control their operation.

[0080] The primary vacuum pump 203 may have an inlet fluidically connected to a pipe 206 of the leak detector 200, communicating with an inlet E of the leak detector 200 configured to be fluidly connected to the internal volume of the object to be tested A.

[0081] The primary vacuum pump 203 is, for example, a dry vacuum pump, such as a diaphragm pump, a scroll pump, or an oil pump.

[0082] The gas analyzer 205 can be configured to provide a measurement signal representative of the flux or concentration of at least one gaseous species used as a tracer gas in the object under test A, placed in an environment exposed to the tracer gas. The gas analyzer 205 is, for example, a mass spectrometer. Alternatively, it can be an optical spectrometer.

[0083] The gas analyzer 205 can be fluidly connected to an inlet of the turbomolecular vacuum pump 202, for example to its suction or to a turbomolecular stage.

[0084] The leak detector 200 may also include a set of valves 207, 209, 211, and 213. At least one or more of these valves may be solenoid valves controllable by the control unit 201. The control unit 201 can be configured to control the opening / closing of at least one valve. It can also detect the open or closed position of at least one valve.

[0085] At least one valve, such as a solenoid valve, can be configured to isolate or connect the gas analyzer 205 with the object to be tested A.

[0086] According to a particular embodiment, the leak detector 200 comprises at least one sampling valve 207 fluidly connected to an inlet of the turbomolecular vacuum pump 202, for example to its suction or to a turbomolecular stage, and a discharge valve 209 fluidly connected to an outlet of the turbomolecular vacuum pump 202.

[0087] The leak detector 200 may further include an isolation valve 211 arranged on the pipeline 206, the isolation valve 211 being interposed between an intersection fluidly connected to the sampling valve 207 and an intersection fluidly connected to the discharge valve 209.

[0088] The leak detector 200 may include at least one so-called venting valve 213, configured to allow air to enter the pipe 206, for example near the inlet E of the leak detector 200. The venting valve 213 allows, in particular in the case of a leak detector 200 operating under vacuum, air to enter the pipe 206 for a return to atmospheric pressure after a leak test in the object to be tested A.

[0089] The sampling valve 207, the discharge valve 209, and the air release valve 213, can be fluidly connected in bypass to the pipeline 206, by respective conduits.

[0090] The leak detector 200 can include a pressure sensor 215 configured to measure the pressure in the pipe 206. The control unit 201 can be connected to the pressure sensor 215 to receive the pressure measurement signals. One or more solenoid valves can be controlled, based on the pressure measured in the pipe 206 via the pressure sensor 215, to initiate a measurement cycle via the gas analyzer 205 during a leak test.

[0091] According to one option, the control unit 201 can detect the open or closed position of at least one valve allowing the isolation or fluidic communication between the leak detector and the internal volume of the object to be tested A, for example the sampling valve 207. The control unit 201 can emit an alert signal when this valve, such as the sampling valve 207, is in the closed position while a spray of a tracer gas flow is commanded.

[0092] The detection assembly 1 can implement at least in part a method for checking the tightness of an object to be tested A by spraying tracer gas, the different stages of which are described below.

[0093] Leak testing method using tracer gas spray

[0094] A first step E1 consists of detecting, by means of the distance sensor 103, whether the spraying device 100 is at the predetermined distance from the object to be tested A whose internal volume is fluidly connected to the leak detector 200.

[0095] An output signal from the distance sensor 103 can be received and analyzed by the processing unit 109 of the spraying device 100.

[0096] Alternatively, the control unit 201 of the leak detector 200 can receive and analyze the output signal from the distance sensor 103 or at least a distance measurement detected by the distance sensor 103. To achieve this, the method may include at least one communication step, in particular wireless, between the communication module of the spray device 100 and the control unit 201 of the leak detector 200.

[0097] If the measured distance does not match the predetermined distance, in other words, if the object to be tested A is not detected, the process stops and the first detection step E1 is repeated. No helium spraying is initiated.

[0098] Conversely, when the predetermined distance is detected, a second step (E2) can be to check the status of the leak detector 200, specifically whether it is active / in the process of taking a measurement or ready to do so. If it is active, a tracer gas spray may be authorized, but if it is in standby (inactive), the spray may be prohibited. This prevents the tracer gas from being sprayed when the leak detector 200 is in a standby mode in which no measurement is being performed.

[0099] This verification of the condition of the leak detector 200 can be done by checking the open or closed position of at least one valve allowing the leak detector 200 to be fluidly isolated or to be fluidically communicated with the internal volume of the object to be tested A. The process then includes a step of checking the open or closed position of at least one valve, such as the sampling valve 207.

[0100] If at least one valve is in the closed position, the spray control may be prohibited. An alert signal may optionally be issued to warn the user at step E20. The alert signal may optionally be transmitted by display or illumination of a light and / or audible pattern at the spray device 100 or the leak detector 200 or any other unit of the detection assembly 1. The procedure repeats the detection steps E1 and verification steps E2, which may be repeated.

[0101] Conversely, if during the E2 verification step, at least one valve is detected in an open position, the process can continue.

[0102] When the predetermined distance is detected, and in particular if the leak detector 200 is active, the spraying of a predefined flow of tracer gas, for a predefined duration, towards the object to be tested A by means of the spraying device 100, can be ordered in step E3. The flow and the duration are chosen according to the application.

[0103] A preliminary step may be to activate the supply of tracer gas to the spray device 100 from the tracer gas source 300. This can be done for example by piloting a valve 301 between the tracer gas source 300 and the inlet 101a of the conduit 101 of the spray device 100.

[0104] For example, the control unit 201 of the leak detector 200 can activate a leak test including the spray control step E3. As another example, the spraying of the predefined tracer gas flow can be controlled by the processing unit 101 of the spray device 100.

[0105] According to a first embodiment, the spraying can be manual. In this case, step E3 of the spraying control may include the emission of at least one warning signal to a user requiring manual actuation of the spraying device 100.

[0106] The warning signal may be a visual and / or audible and / or haptic or vibration signal, for example at the handle or trigger 107 when the spraying device 100 is in the form of a spray gun.

[0107] A visual signal may be displayed on the screen of the spray device 100. This may consist of lighting up or flashing an indicator light on the housing of the spray device 100, for example at the trigger 107. Alternatively or in addition, an audible signal may consist of a sound pattern emitted through the speaker of the spray device 100. In yet another alternative or in addition, the trigger 107 may vibrate.

[0108] This warning signal may be different from the possible alert signal emitted at step E20, when the leak detector 200 is in standby mode.

[0109] According to a second embodiment, the spraying can be automated. In this case, the E3 step of controlling a spray can trigger an automatic piloting of the spraying device 100.

[0110] During spraying, it is best to remain still. However, spraying can also occur while the spraying device 100 is moving, for example by moving it around the object being tested A.

[0111] During the predetermined duration of the spraying, the distance sensor 103 can continuously check the distance between the spraying device 100 and the object to be tested A. If during the spraying, the detected distance no longer matches the predetermined distance, the spraying continues until its end without issuing a counter-command to stop the spraying before the end of this predetermined duration.

[0112] One or more E4 detection steps are also implemented by the leak detector 200 during the leak test, for the search for possible presence of the tracer gas in the object to be tested A.

[0113] During detection step E4, the flow or concentration of tracer gas in the object under test A can be measured. Specifically, at least one valve can be controlled to establish fluidic communication between the internal volume of the object under test A and the gas analyzer 205. The inlet E of the leak detector 200 can sample a portion of the gases contained in the object under test A. A portion of the gas thus sampled, possibly containing the tracer gas that reveals a leak, is then analyzed by the gas analyzer 205, which provides a signal measuring the tracer gas flow in order to identify and locate any potential leak.

[0114] The control unit 201 can control a release to air following a leak test in the object to be tested A.

[0115] The control procedure may include at least one step of modifying at least one parameter of the leak detector 200, which may be carried out at least partially simultaneously with the tracer gas spray command E3. An example of a leak detector parameter could be a signal processing parameter used in leak detection (e.g., an averaging function) to enable leak detection.

[0116] Thus, the installation of a distance sensor 103 at the end of the spraying device 100 makes it possible to detect and manage a precise location where helium is sprayed onto the object to be tested A. When the predetermined distance is detected, the correct amount of helium can be sprayed at the correct distance from the object to be tested A. This avoids unnecessarily spraying tracer gas at too great a distance, and polluting the surrounding environment, which is useless for measurement by the leak detector 200.

Images