System for detecting leaks and associated methods

Abstract

The present invention relates to a system (20; 20') for detecting leaks of a component having a permeable area, said system comprising: a test chamber (22, 22') configured to house the component to be tested; means (24) suitable for varying the pressure in said test chamber and / or in said component to be tested; measuring means (26) for measuring a physical quantity indicative of the level of leakage; characterized in that said system (20; 20') comprises a dry pipe (30) configured to cooperate with said permeable area of said component, one end (30a) of said dry pipe (30) being in communication with said permeable area, while the other end (30b) of said pipe (30) is open outside said test chamber (22; 22').

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of systems for detecting leaks or for measuring tightness, more specifically to a leak detection system based on the measurement of a physical quantity (e.g. pressure or flow rate) with respect to a leak level. BACKGROUND

[0002] In fact, it is necessary to be able to check the integrity of a product and / or to check whether a product is leaking and to be able to quantify said leak. The products / components to be tested are, for example, electronic devices, mechanical components, containers, etc.

[0003] Tightness is a key characteristic in the case of products subjected to strict external constraints and which need to meet specific operating requirements, such as impermeability to liquids (e.g. water), absence of leaks that could reduce the performance of the product, etc.

[0004] More specifically, there is a specific type of product in which certain parts must have a certain degree of tightness (e.g. remain tight at a depth of 1 m) while other parts are not in a tight condition (but in themselves, especially when these products are not tested in the position of use / assembly).

[0005] Two specific examples are given here as indicative examples only and can therefore be considered as:

[0006] - electronic devices, such as smartphones, tablets, smartwatches, etc., which must have a certain degree of tightness to liquids (e.g. water), but also contain permeable areas, such as openings connecting the inside and the outside of the device, which are usually sealed by membranes that are permeable to air but not to liquids (e.g. ) in order to keep the inside of the device at atmospheric pressure.

[0007] - liquid cartridges of electronic cigarettes (electronic cigarettes or e-cigarettes), of which a very schematic example is represented in Figures la to lc , in perspective view, cross-sectional view and front view, in which it can be seen that the cartridge 1 comprises a tank 3 intended to store a liquid, a suction pipe 5 passing through said cartridge 1 and surrounded by said tank 3, and a wick 7, which is arranged across the suction pipe 5 and whose end is located in said tank 3.

[0008] Moreover, the tank 3 is usually delimited by a wall and by a sealing member 9 (for example, a rubber cap) so as to close the tank 3 after filling. It should be noted that the suction pipe 5 of the cartridge 1 is made by bending a metal sheet, on which a weld 11 is made to finally complete the pipe 5, which is usually inside the suction pipe 5 (along the wall delimiting the inside of the pipe). Moreover, in order to have the end of the wick 7 inside the tank 3, an opening is arranged in the wall 5a of the suction pipe 5 so as to have the wick 7 immersed in the liquid and the liquid soaked in the wick 7.

[0009] Therefore, the electronic cartridge must have a satisfactory tightness at the elements delimiting the tank (for example, the outer wall and the sealing member), while at the suction pipe it comprises a permeable area (due to the insertion of the wick through the opening in the tank).

[0010] Therefore, the design of these components itself has a permeable area, which enables the communication between the inside and the outside of the component. Said permeable area can also be equivalent to a leak which is greater (or even much greater, for example, by 100 orders of magnitude) than the leak sought to be determined in another area of the component (in the above example, the outer wall of the object).

[0011] It should be noted that the term "permeable area" indicates an area which is at least passable by a liquid (for example, water) and / or a gas (for example, air).

[0012] For this type of product, the method usually used to test the tightness of the components is the so-called "sealed assembly" method.

[0013] This method first comprises sealing the component to be tested in a gas-tight manner, for example, by sealing the end of the suction pipe of the cartridge or the gas-permeable membrane of the electronic device.

[0014] Then, the sealed component to be tested is subsequently placed in a test chamber, the pressure in the test chamber is varied in a controlled manner (for example, by injecting a gas, for example, air), and the pressure variation after a predetermined time is measured. In fact, if the accessible volume is greater than the volume of the test chamber from which the volume of the component to be tested is subtracted, there is a variation in the gas pressure which reflects the volume actually accessible to the gas, i.e., the volume of the test chamber and at least part of the internal volume of the component if it is not in a tight condition.

[0015] However, with this method, it is necessary to perform a teaching test cycle on the components which are satisfactorily tight, so as to be able to subsequently distinguish between tight components and components with leaks and / or to make a differential measurement (i.e., comparing the pressure in two test chambers, one containing the component to be tested and the other containing a component considered "satisfactorily tight").

[0016] Therefore, the drawback of this method is the need for the operator to have a certain expertise in order to correctly calibrate the leak detection system and / or to seal the component to be tested.

[0017] Furthermore, when leak detection is performed on a component having a small internal volume, this method can be difficult to implement for slight leaks and / or for components in which rigidity (or flexibility) affects the accuracy of the results (deformation of the component due to pressure variations can cause errors in the leak measurement results).

[0018] There is therefore a need for a leak detection device and method that make it possible to check the tightness of components that have permeable areas due to their specific function. SUMMARY

[0019] The present invention is particularly advantageous for leak detection on components having permeable areas that connect at least one internal part of the component with the outside.

[0020] The present invention therefore at least partially solves the above-mentioned problems by proposing a new leak detection system for components having permeable areas, the system comprising:

[0021] - a test chamber configured to receive the component to be tested;

[0022] - means adapted to vary the pressure in the test chamber and / or in the component to be tested;

[0023] - means for measuring a physical quantity representative of the level of leak;

[0024] characterized in that it comprises a dry pipe configured to cooperate with the permeable area of the component, one end of the dry pipe being in communication with the permeable area and the other end of the pipe being open outside the test chamber.

[0025] Thanks to the presence of a pipe in communication with the area of the component having a permeable area, it is possible to better isolate the component to be tested from the test chamber, thus making the tightness test simpler and more repeatable, in particular by avoiding the need to perform a teaching test cycle on a component considered to be tight (and thus avoiding having to use the "sealed assembly" method).

[0026] According to a possible feature, the system comprises an insert in which the dry pipe is arranged.

[0027] It is advantageous for the dry pipe to be arranged in a separate and removable component, which is easier to adapt according to the type of component to be tested.

[0028] According to another possible feature, the system comprises two seals that ensure the tightness between the outside and the inside of the component to be tested.

[0029] More specifically, the way the seal is arranged should ensure that tightness is created on a certain portion of the component, trying to test the tightness of this portion, for example, via permeable area and dry tube.

[0030] Thus, for electronic devices such as tablets, the dry tube is positioned in communication with the opening comprising the air-permeable membrane and the seal is positioned at the wall of the insert pressed against the component to be tested (it should also be noted that the seal can be arranged at the wall of the chamber through which the insert passes), while for electronic cigarettes, the insert is inserted into the suction tube and the seal is positioned against the wall of the suction tube.

[0031] Given that the contact area with the seal can have an uneven surface, it is particularly important to have the benefit of at least two seals, as is the case with electronic cigarettes, in which the suction tube has a weld along said tube.

[0032] In fact, if said seal were not present, the measured leak could be a leak at the seal rather than an intrinsic leak of the component to be tested.

[0033] It should also be noted that when trying to measure very small leaks with a short test time, it is preferable to minimize the volume variations in which the physical quantity representative of the leak is measured (for example, the volume variations caused by the displacement of the seal affected by the pressure difference between the two faces of the seal).

[0034] According to a possible feature, the system comprises a branch open between the two seals. Said branch is arranged, for example, in said insert.

[0035] Thanks to the presence of the branch, it is possible to vary the pressure established between the two seals in order to limit the displacement of the seal in contact with the test volume and / or to test the level of leak at said seal. It should be noted that the gap between the two seals is also referred to in the following as the term "inter-seal volume".

[0036] According to another possible feature, the means adapted to vary the pressure in the test chamber are configured to vary the pressure according to the pressure gradient (i.e. according to the variation of pressure per unit of time).

[0037] In fact, the leak to be detected and to be measured can be associated with elements having a non-linear behavior, i.e. a component can not have a leak at a given pressure, while it can have a leak at another pressure. It is therefore advantageous to vary the test pressure within a given pressure interval in order to optimize the possible leak detection (for example, a variation of 5 bar in 10 seconds). The pressure variation, in particular the pressure variation in the test chamber, is preferably linear and continuous, but it can also be a series of plateau pressures.

[0038] According to another possible feature, the component to be tested is an electronic device having an opening sealed by a membrane permeable to gas, for example air, and impermeable to liquid, for example water.

[0039] According to another possible feature, the component to be tested is an electronic cigarette liquid cartridge comprising a liquid tank, a suction tube and a wick, the wick being disposed across the tube and at least one of its ends being located in the tank.

[0040] According to another possible feature, the measuring device comprises a differential pressure sensor. The differential sensor makes it possible in particular to carry out a tightness measurement by including the component to be tested to the reference component, which helps to partially avoid parasitic effects due to the environment in which the test is carried out.

[0041] According to another possible feature, the leak detection is carried out via a dry tube.

[0042] It is advantageous to use a dry tube to measure the physical quantity related to the leak, since this simplifies the assembly and avoids providing another measurement point in the test chamber.

[0043] Furthermore, the system according to the invention aims to detect very low levels of leak in the event of the presence of an intrinsic leak of the component to be tested, a leak of permeable area, so that it is not problematic to obtain a measurable level of leak limited by the level of leak of permeable area.

[0044] The invention also relates to a novel leak detection method for a device as described above, in which a first seal isolates the inside of the component to be tested from an inter-seal volume, and a second seal isolates the inter-seal volume from the outside of the component to be tested,

[0045] characterized in that it comprises the following steps:

[0046] - establishing a first pressure similar in the test chamber and in the inter-seal volume;

[0047] - determining a first level of leak;

[0048] - establishing a second pressure in the inter-seal volume similar to the pressure of the dry tube of the insert;

[0049] - determining a second level of leak;

[0050] - determining a level of leak of the component based on the first level of leak and the second level of leak.

[0051] According to a possible feature, the method comprises a step of determining a leak correction factor, for example associated with the first seal.

[0052] The leak correction factor serves to correct the value of the first level of leak.

[0053] According to another possible feature, if the correction factor is less than a predetermined value, the measurement of the first leakage level is declared valid.

[0054] According to another possible feature, if the correction factor is greater than a predetermined value, a warning is triggered.

[0055] According to another possible feature, the first leakage level and / or the second leakage level are determined based on at least one pressure interval (e.g. pressure gradient). BRIEF DESCRIPTION OF DRAWINGS

[0056] The application will be better understood in the course of the following description of particular embodiments thereof, given solely by way of illustration and non-restrictive, with reference to the attached drawings, in which:

[0057] [ Figure la ] is a very schematic representation of an e-liquid cartridge;

[0058] [ Figure lb ] is a very schematic representation of an e-liquid cartridge;

[0059] [ Figure lc ] is a very schematic representation of an e-liquid cartridge;

[0060] [ Figure 2 ] is a very schematic representation of a detection system according to the application in a first application example;

[0061] [ Figure 3 ] is a zoomed view of a sub-portion of the system in Figure 2 ;

[0062] [ Figure 4a ] is a very schematic representation of a detection system according to the application in a second application example;

[0063] [ Figure 4b ] is a zoomed very schematic view of a sub-portion of the system in Figure 4a ; DETAILED DESCRIPTION

[0064] Figure 2 is a very schematic representation of a detection system 20 according to the application in a first application example, wherein said leakage detection system 20 is used on a cartridge 1 as described with reference to Figures la to lc ;

[0065] Thus, said system 20 comprises:

[0066] - a test chamber 22 configured to receive a component to be tested, here said cartridge 1 (represented very schematically);

[0067] - means 24 suitable for varying the pressure in the test chamber 22;

[0068] - measuring means 26 for measuring a physical quantity indicative of the level of leakage, such as a pressure gauge or a flow meter;

[0069] - an insert 28 (or connecting portion) configured to cooperate with a region of the cartridge 1 comprising a permeable region.

[0070] The insert 28 is thus inserted into the suction pipe 5 of the cartridge 1 via one end of said pipe, while the other end of said pipe is sealed by a sealing member, such as a cap.

[0071] As shown in greater detail in Figure 2 The insert 28 thus comprises at least one dry pipe 30, one end 30a of which communicates with the permeable region of the component, while the other end 30b is open outside the test chamber 22.

[0072] More specifically, the dry pipe 30 preferably opens into the suction pipe 5 of the cartridge 1 near the core 7 of said cartridge, and the opening is thus arranged in a wall 5a delimiting said pipe 5 and communicating with the tank 3 (and thus at the permeable region of the component).

[0073] The insert 28 also comprises:

[0074] - at least two seals 32a and 32b, referred to as first seal 32a and second seal 32b, configured to ensure the tightness between the outside of the component 1 and the permeable region;

[0075] - a branch pipe 34 open between said two seals;

[0076] - a main body 36 in which the dry pipe 30 and the branch pipe 34 are arranged.

[0077] It should be noted that, in the example represented in Figure 2 and 3 The insert 28 comprises two O-ring seals 32a and 32b, which are mounted on the outer periphery of said insert 28 and are placed in contact with the wall 5a of the pipe 5, but said seals 32a, 32b can be placed differently depending on the structure of the component to be tested. The space delimited by said seals 32a and 32b, the wall 5a of the suction pipe 5 and the main body 36 of the insert 28 defines a volume 37, referred to as inter-seal volume (said secondary channel 34 thus opens into the inter-seal volume 37).

[0078] The first seal 32a of the insert 28 isolates the inside of the cartridge to be tested from the inter-seal volume 37, while the second seal 32b isolates the inter-seal volume 37 from the outside.

[0079] Moreover, it should be noted that, despite the poor surface conditions of the wall 5a of the tube 5 (in particular due to the presence of the weld 11), the presence of the two seals ensures a certain level of tightness.

[0080] The insert 28 can also comprise means 39 for fixing the seals, configured to fix the seals 32a and 32b in position and to maintain a predetermined distance between them.

[0081] Moreover, when trying to test the level of tightness of the cartridge 1, a leak detection method is applied comprising the following steps:

[0082] - a first pressure PI is established in the inter-seal volume 37 and in the test chamber 22, while the pressure in the suction tube 5 is kept, for example, at atmospheric pressure (this can be achieved simply by means of the dry tube 30 and the valve which are open outside the test chamber 22).

[0083] - a first level of leakage FI is determined, this determination being performed by measuring the variation over time of a physical quantity (for example, by means of the dry tube of the insert), such as the variation in pressure in the test chamber or in the suction tube 5.

[0084] - a second pressure P2 is established in the inter-seal volume 37 and in the region of the component to be tested which has a controlled leak (here, the inside of the suction tube 5 of the cartridge 1) (this also limits the displacement of the first seal 32); it should be noted that the second pressure P2 is, for example, equal to atmospheric pressure.

[0085] - a second level of leakage F2 is determined, as mentioned above, this determination being performed by measuring the variation over time of a physical quantity (for example, by means of the insert 28), such as the variation in pressure in the test chamber 22 or at the suction tube 5.

[0086] - the level of leakage F of the component is determined on the basis of the first level of leakage FI and the second level of leakage F2 determined previously p .

[0087] The first level of leakage FI determined can therefore contain the measurement of the leak associated with the poor tightness at the seals 32a and 32b (in particular the first seal 32a) and with other uncontrolled phenomena, displacement of the seals, temperature variations, etc.

[0088] While the second level of tightness F2 determined measures a leak which does not contain the leak at the first seal 32a.

[0089] During the determination of the level of leakage, the method can also comprise the step of determining a leakage correction factor for correcting the value of the first level of leakage FI (for example, associated with the leak at the first seal).

[0090] According to the value of this correction factor, for example if the value of the first leakage level is not modified by more than 5%, the measured value of the first leakage level F1 is declared valid and is therefore considered as representative of the tightness level of the component under test.

[0091] If the correction factor is greater than a predetermined value, an alarm is triggered, indicating to the user that there is a problem in the leak detection performed, for example a damaged or poorly positioned seal and that the seal should be better seated or replaced.

[0092] The current detection method can also comprise an additional step in which the correction factor is used to calculate a corrected leakage level F1'(the correction factor being applied to the first leakage level F1 ) so as to enable the operator / user to know whether the component under test complies with the requested tightness criteria.

[0093] Furthermore, it should be noted that the current method can be performed by a set of discrete pressure values or pressure intervals (or pressure gradients).

[0094] Figure 4a A second application example is shown in itself of a leak detection system according to the application, in which the leak detection system 20' is used on electronic devices 41, 41'having permeable areas, for example openings 41 a, 41 a' sealed by a membrane permeable to air but not to liquid, for example a membrane permeable to air but not to water. The membrane.

[0095] It should be noted that the same references have been used to denote similar elements.

[0096] Thus, the system 20' comprises:

[0097] - a first test chamber 22 and a second test chamber 22' configured to receive respectively a component 41 and a reference component 41'to be tested, here electronic devices;

[0098] - a device 24 suitable for varying the pressure in the test chambers 22, 22';

[0099] - a measuring device 26 for measuring a physical quantity representative of the leakage level, for example a pressure gauge or a flow meter;

[0100] - an insert 28 cooperating respectively with each electronic device area comprising respectively a permeable area, here an opening 41 a, 41 a' sealed by a membrane.

[0101] As mentioned above, each of the inserts 28 has a dry tube, one end of which communicates with the permeable area 41 a, 41 a' of the component 41, 41'and the other end is open outside the test chamber 22, 22'.

[0102] Therefore, it should be noted that the structure of each of the inserts 28 is substantially the same as that described above with reference to Figure 2 and 3 the difference being that when the insert 28 has two seals 32a and 32b, the seals 32a and 32b are arranged at the wall of the test chamber 22 and 22' and / or between the wall of the insert 28 and the wall of the permeable area 41a, 41a' of the surrounding member 41, 41'. Figure 4b The configuration of the seals arranged between the walls is shown in more detail in Figure 4b is a very schematic enlarged view of the contact area between the dry tube 30 of the insert 28 and the permeable area 41a.

[0103] The device 26 for measuring the physical quantity representative of the level of leakage comprises a differential pressure sensor and is connected to each of the inserts 28, more specifically by means of the dry tube 30 of the insert 28.

[0104] Therefore, the leakage detection performed on the component to be tested can be performed in the same way as the method described above.

[0105] However, the leakage detection method is advantageously performed by comparing the variation of the physical quantity (for example pressure or flow rate) representative of the level of leakage between the component 41' to be tested and the reference component 41, making it possible to avoid variations related to the environment.

[0106] However, in alternative embodiments not shown, the leakage detection of the electronic device can be performed without a reference component, as in the scope of the first application described above.

[0107] Advantageously, the first pressure PI and / or the second pressure P2 can be a pressure interval and more specifically a pressure gradient (i.e. a pressure variation per unit of time), preferably continuous and linear. The variation of the pressure over time can also be a succession of plateau pressures.

Claims

1. A system (20 for detecting leaks in a component having permeable regions; 20'), said system comprising: - a test chamber (22, 22') configured to house a component to be tested; - means (24) adapted to vary the pressure in said test chamber and / or in said component to be tested; - measuring means (26) for measuring a physical quantity indicative of a level of leakage; wherein said system (20; 20') comprises a stem (30) configured to cooperate with said permeable region of said component, one end (30a) of said stem (30) being in communication with said permeable region, while the other end (30b) of said stem (30) is open outside said test chamber (22; 22'); characterized in that said system (20; 20') further comprises: - a first seal (32a) and a second seal (32b), said seals ensuring the tightness between the outside and the inside of said component to be tested and defining an inter-seal volume (37) between said first seal (32a) and said second seal (32b), said first seal (32a) isolating said inside of said component to be tested from said inter-seal volume (37), said second seal (32b) isolating said inter-seal volume (37) from said outside of said component to be tested; - a branch (34) open in said inter-seal volume (37), and - an insert (28) configured to cooperate with said permeable region of said component having said permeable region, wherein said insert (28) comprises a main body (36) in which said stem (30) and said branch (34) are arranged, and wherein said first seal (32a) and said second seal (32b) are mounted on said insert (28), and wherein said measuring means (26) detect a leakage in said component to be tested using a first pressure (PI) established in said test chamber (22; 22') through said stem (30) and a second pressure (P2) established in said inter-seal volume (37) through said branch (34). Said means (24) adapted to vary said pressure in said test chamber (22) and / or in said component to be tested are configured to vary said pressure as a function of a pressure gradient.

2. The system of claim 1, wherein, Said component to be tested is an electronic device (41, 41') having an opening (41a, 41a') sealed by a membrane permeable to gas and impermeable to liquid.

3. The system of claim 1, wherein, Said component to be tested is an electronic cigarette liquid cartridge (1) comprising a liquid tank (3), a suction tube (5) and a wick (7) disposed across said suction tube (5) and having at least one end located in said liquid tank (3).

4. The system of claim 1, wherein, Said measuring means (26) comprise a differential pressure sensor.

5. The system of claim 1, wherein, Leakage detection is performed by means of connecting said measuring means (26) to said stem (30) of said insert (28).

6. The system of claim 1, wherein, Said method comprises the following steps:

7. A leak detection method for the apparatus of claim 1, a first seal (32a) isolating the interior of the component under test from a seal inter-volume (37), a second seal (32b) isolating the seal inter-volume (37) from the exterior of the component under test, characterized in that, - establishing at least a first pressure (PI) in said test chamber (22; 22') and in said inter-seal volume (37) respectively through a stem (30) and a branch (34); - determining a first level of leakage (Fl); - establishing at least a second pressure (P2) in said inter-seal volume (37) through said branch (34); - determining a second level of leakage (F2); - establishing at least a third pressure (P3) in said test chamber (22; 22') through said stem (30); - determining a third level of leakage (F3). - establishing a second pressure (P2) in the inter-seal volume (37) through the branch (34); - determining a second leakage level (F2); - determining a leakage level (F) of the component based on said first leakage level (F1) and said second leakage level (F2) p ), the former comprising measuring leakage associated with poor tightness at said first seal (32a) and said second seal (32b), the latter measuring leakage not including leakage at said first seal (32a).

8. The method of claim 7, wherein, There is a step of determining a leakage correction factor for correcting the value of the first leakage level (Fl).

9. The method of claim 7, wherein, The first leakage level (Fl) and / or the second leakage level (F2) are determined on the basis of at least one pressure variation per unit of time.

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