Test leak device

Abstract

The invention relates to a test leak device (10) for testing and calibrating a leak-detection device which has a test chamber that can be evacuated and is provided for accommodating a test object and / or the test leak device (10), wherein the test leak device (10) has an interior (20) which is surrounded by a housing (11) and can be filled with a test fluid, the housing having a through-opening (22) connecting the interior (20) to the outer surroundings of the test leak device (10), and a membrane (25) which can be brought into or onto the through-opening (22) and is permeable to the test fluid or to components of the test fluid. According to the invention: the membrane (25) is part of a membrane element (24) which fits sealingly on or in the through-opening (22); the membrane element has a carrier element (42) which is designed to be releasably fastened to the housing (11) and which closes the through-opening when fastened so that the interior (20) can be filled with test fluid through the through-opening (22) when the carrier element exposes the through-opening; and the carrier element has an outlet duct (44) which completely penetrates the carrier element and is closed by the membrane in such a way that only test fluid or components of the test fluid can escape from the interior (20) through the membrane (25) and to the outside.

Description

[0001] Test leak device

[0002] The invention relates to a test leak device for testing the functionality and calibrating a leak detection device.

[0003] Leak detection devices typically comprise an evacuable test chamber into which a gas-filled or liquid-filled test specimen is placed. A gas analysis device is connected to the test chamber, which analyzes the gas extracted from the test chamber to detect any leakage gas that has escaped into the test chamber from a leak in the test specimen, or liquid escaping and evaporating from the leak. It is particularly important to be able to determine the size of the leak from the amount of leakage gas detected. For this purpose, test leak devices are used. These contain a predetermined quantity of a known test gas or test fluid and are equipped with a leak with known dimensions and / or with known permeability to the fluid contained therein.Test leak devices are typically used to verify the functionality of a leak detection device and to calibrate the leak detection device.

[0004] The leak of a test leak device is often designed as a membrane, the leak rate of which depends on the permeability of the membrane body for the respective test gas or test fluid, on the membrane temperature, on the temperature and the vapor pressure of the test gas / test fluid, on the degree of wetting of the membrane on the inside / fluid side and on the ventilation on the outlet side of the membrane, i.e. on the outside of the test leak device.

[0005] For example, EP 2 447 694 B1 describes a liquid-filled test leak from which gas or vapor, or liquid components transported by the gas, escape. The gases escaping from the test leak, or the escaping vapor or the escaping liquid components transported by the gas, are formed by the liquid through its own vapor pressure or by permeation through a solid layer of a membrane.

[0006] The leak rate of a membrane test leak depends on whether and to what extent the inside of the membrane is wetted with liquid. Whether a liquid or only liquid vapor is in direct contact with the membrane can have a significant influence on the leak rate. To achieve a stable leak rate, one should either prevent liquid from reaching the membrane or ensure that only liquid vapor comes into contact with the membrane. DE 10 2014 200 907 B4 describes a reference outgassing system with a reservoir containing a fluid or a fluid mixture. A transport vacuum chamber surrounds the reservoir. The chamber pressure in the transport vacuum chamber is less than 10 kPa.

[0007] DE 10 2020 116 939 A1 describes a test leak device in which the bottom of the reservoir for the test fluid tapers conically toward the membrane. It is mentioned that the membrane is attached with screws. A separate filling opening is described for filling the reservoir with test fluid.

[0008] The invention is based on the object of creating an improved refillable test leak device.

[0009] The test leak device according to the invention is defined by the features of patent claim 1. The method according to the invention is defined by the features of patent claim 10.

[0010] The leak test device according to the invention has an interior space surrounded by a housing and fillable with a test fluid. The housing is provided with a through-opening that connects the interior space to the external environment of the leak test device. A membrane that is permeable to the test fluid or to components of the test fluid is provided to be attached to the through-opening in such a way that test fluid or components of the test fluid can escape from the interior space through the through-opening through the membrane to the outside. For this purpose, the membrane preferably has a predetermined, known permeability so that the test fluid leaves the leak test device with a known leak rate.

[0011] The special feature of the invention is that the through-opening is used to fill the interior with test fluid, whereas in the prior art separate filling openings are provided for this purpose and the through-opening closed with the membrane is used exclusively for the escape of the test fluid from the interior into its external environment.

[0012] For this purpose, the membrane is part of a membrane element that fits sealingly onto or into the through-opening and has a support element designed for releasable attachment to the housing. The support element is preferably made of a rigid material, such as stainless steel. The support element is designed such that it closes the through-opening when attached to the housing. To fill the interior with test fluid, the support element is detached from the housing, and test fluid is poured into the interior through the through-opening. The support element is then reattached to the housing, thereby closing the through-opening.

[0013] The support element is provided with an outlet channel that extends completely from a first side to its opposite second side. The outlet channel is sealed by the membrane in such a way that only test fluid or components of the test fluid can escape from the interior through the membrane. The connection between the support element and the housing is designed to be fluid-tight and therefore also gas-tight.

[0014] The through-hole typically has a larger opening diameter than the outlet channel, allowing rapid refilling of the interior with test fluid, for example, using a filler neck that matches the through-hole. The diameter of the outlet channel is independent of that of the through-hole and is adapted to the size of the membrane or has the dimensions required for the escape of test fluid from the interior. Thus, the test leak device according to the invention is easily refilled via the through-hole without the need for separate filling openings, enabling a technically simplified and more reliable design.While conventional test leak devices are either not refillable or can only be refilled via separate filling openings, according to the invention, to refill the test leak device, the attachment of the carrier element to the housing is first loosened and the membrane element is removed from the through-opening. The interior is then filled with test fluid via the through-opening, for example by inserting a suitable filling nozzle into the through-opening. After filling, the carrier element is reattached to the housing so that a fluid-tight, i.e. liquid- and gas-tight, connection is created between the carrier element and the housing and test fluid or components of the test fluid can escape from the interior exclusively through the membrane.

[0015] The permeability of the membrane element can be measured after the membrane is connected to the support element, before the membrane element is connected to the housing. This allows the leak rate of the test leak device to be determined and specified based on the qualification of the membrane on the support element, thus being independent of the filler material.

[0016] The support element can be designed as a flange. The outlet channel can be formed at the center of the support element. Fastening devices distributed around the outlet channel can be provided for attaching the support element to the housing.

[0017] In particular, the support element can be designed as a flange that allows attachment to a complementary mating flange of a test chamber such that test fluid can escape from the interior of the test leak device directly into the interior of the test chamber through the created flange connection. For this purpose, the flange of the test leak device is attached to the mating flange of the test chamber in a fluid-tight and releasable manner. This allows for easy testing of the functionality and calibration of a leak detection device without having to open the test chamber and insert the test leak device into the test chamber.The fastening devices can, for example, be screw holes, while corresponding threaded openings are formed in the housing, so that in the fastened state of the support element, each screw hole is aligned with a corresponding threaded opening so that a screw can be screwed through each screw hole into the corresponding threaded opening.

[0018] It is advantageous if a separate sealing ring is arranged between the support element and the housing, surrounding the through-hole in plan view, in particular to seal the through-hole against the threaded openings and screw holes. The sealing ring can be metallic, e.g., in the form of a copper ring ("CF vacuum technology") or an aluminum ring (as an "ultra seal"). The sealing ring is replaced after a filling process. A metallic seal is preferable here because it is not permeable to gases and liquids and does not store gases and liquids and release them again with a delay, as is the case with elastomer seals. Additional permeation through the seal or outgassing would falsify the actual calibration.

[0019] The outlet channel can also be cylindrical. The diameter of the outlet channel is smaller than that of the through-hole. While the diameter of the through-hole must be sufficiently large for quick, easy, and safe filling, the diameter of the outlet channel can be sufficiently small for the targeted escape of the test fluid from the interior at a specified leak rate.

[0020] The membrane is preferably designed as an element covering the outlet channel, for example in the form of a disc. The membrane can be attached to the outer side of the support element opposite the interior space and, for example, can be firmly glued or pressed to the support element. A recess for the support element surrounding the outlet channel can be formed in the surface of the support element, into which recess the membrane fits precisely. Preferably, the membrane is firmly glued or pressed to the support element in the recess. The membrane can also be covered by a protective grid that supports the membrane and is attached to the support element.

[0021] Preferably, the test leak device according to the invention does not have a separate filling opening for filling the interior space with test fluid, so that the interior space can be refilled with test fluid exclusively through the through-opening.

[0022] In one embodiment, a cover cap may be provided that conceals the support element and is connected or attached to the housing. The connection between the cover cap and the housing is preferably detachable. The cover cap provides a protective function for the membrane and the support element.

[0023] The housing of the leak test device has a base, a lid, and at least one side wall connecting the base to the lid. The base, lid, and side wall enclose the interior space that can be filled with the test fluid. The test fluid can be a test gas or a test liquid. The membrane is permeable to the test gas or to components of the test liquid, so that only the test gas or components of the test liquid can escape from the leak test device through the membrane.

[0024] An embodiment of the invention is explained in more detail below with reference to the figures.

[0025] Fig. 1 is a perspective section through the embodiment,

[0026] Fig. 2 shows a cross section through the embodiment according to Fig. 1 and Fig. 3 shows an exploded view of an embodiment.

[0027] The leak test device 10 comprises a housing 11 with a base 12, which is integrally connected to a circumferential side wall 14 projecting laterally from the outer edge of the base. A cover 16 is fluid-tightly connected to the side wall 14 such that the base 12, the side wall 14, and the cover 16 enclose an interior space 20 in a fluid-tight manner. The interior space 20 can therefore be filled with a test fluid, i.e., a test gas or a test liquid. The base 12, the circumferential side wall 14, and the cover 16 form the housing 11.

[0028] Formed in the base 12 is a through-opening 22 connecting the interior space 20 to the external environment 13 of the leak test device 10. A membrane element 24 is inserted into the through-opening 22. The membrane element 24 has a membrane 25 permeable to the test fluid or to components of the test fluid. As a result, the test fluid contained in the interior space 20 can exit the leak test device 10 exclusively through the membrane 25.

[0029] The membrane element 24 has a cylindrical support element 42, which, as a rotational body, has a rotational axis that, in the state shown in Fig. 2, in which the support element 42 is connected to the housing 11, coincides with the rotational axis of the likewise rotationally symmetrical housing 11. The rotational axis of the support element 42 and the housing 11 is shown in Fig. 2 as a dashed line.

[0030] The support element 42 is penetrated by an outlet channel 44 which runs concentrically through the center of the support element along its axis of rotation, so that an outer end face of the support element facing the environment 13 is connected by the outlet channel 44 to the opposite end face of the support element 42 facing the interior space 20. The side wall 14 is designed as a ring which extends cylindrically along the outer circumference of the base 12 and projects upwards from the base 12, the inner side 26 of which forms a cone which tapers towards the membrane device 24 and the through-opening 22. At its lower end facing the base 12, the cone has a central opening which opens into the through-opening 22 and adjoins the membrane device 24.

[0031] Because the base 12 and the side wall 14 are integrally connected to one another, the cone of the inner side 26 can also be regarded as a recess in the base 12.

[0032] The test fluid contained in the interior space 20 flows along the inner side 18 due to the effect of gravity and the diameter of the interior space 20 tapering towards the through-opening 22 and the membrane 25. The membrane is thereby evenly wetted by test fluid as soon as the test leak device 10 is upright on a surface, such as the floor of the test chamber of a leak detection device not shown in the figures.

[0033] The underside 28 of the base 12 has a plate-shaped curvature 30 concentrically surrounding the through-opening 22. The membrane element 24 is inserted into the lower end of the through-opening 22. The through-opening 22 opens into the interior 20 with a diameter that is smaller than that of the membrane element 24. As a result, a cylindrical recess surrounded by the curvature 30 is formed in the base 12, into which the membrane element 24 is inserted. The recess completely accommodates the membrane element 24.

[0034] The through-opening 22 is concentrically surrounded by screw holes 40 formed in the base 12, into which fastening elements in the form of screws for securing the membrane element 24 are inserted and held there by a conventional screw connection with threaded engagement. The support element 42 is provided with threaded channels or threaded openings 46, which are arranged concentrically around the outlet channel 44 and are aligned with the screw holes 40 in such a way that a screw 48 is screwed into a screw hole through each threaded opening 46. This holds the support element 42 firmly but releasably to the housing 11.

[0035] A sealing ring 50 in the form of a copper ring ("CF vacuum technology") is provided between the carrier element 42 and the housing 11. This sealing ring 50 surrounds the through-opening 22 on the outside and forms a fluid-tight seal between the carrier element 42 and the housing 11. As a result, no test fluid can pass from the through-channel into the screw holes 40 or the threaded openings 46. In the state shown in Figs. 1 and 2, only test fluid can pass through the membrane 25 from the interior space 20 into the external environment 13.

[0036] To refill the test leak device 10, first unscrew the screws 48 from the threaded openings 46 and remove the membrane device 24 from the through-hole 22. The interior 20 is then filled with test fluid through the through-hole 22. The sealing ring 50 is replaced with a new one if necessary, for example, in the event of wear. The sealing ring is then inserted into the designated opening between the housing 11 and the support element 42, and the support element 42 is then firmly screwed to the housing 11 again using the screws 48. The membrane 25 remains firmly bonded or pressed to the support element 42 and does not need to be removed.

Claims

Claims: Test leak device (10) for testing and calibrating a leak detection device, which has an evacuable test chamber for receiving a test specimen and / or the test leak device (10), wherein the test leak device (10) has an interior space (20) surrounded by a housing (11) and fillable with a test fluid, wherein the housing separates the interior space (20) from the external environment of the test leak device (10) connecting through-hole (22) and a membrane (25) that can be placed in or onto the through-hole (22) and that is permeable to the test fluid or to components of the test fluid, characterized in that the membrane (25) is part of a membrane element (24) that fits sealingly onto or into the through-hole (22), and that the membrane element is designed for detachable attachment to the housing (11) a carrier element (42) which closes the through-opening in the fixed state in order to allow the interior (20) to be filled with test fluid through the through-opening (22) when the carrier element releases the through-opening, such that the carrier element has an outlet channel (44) that completely penetrates the carrier element and is closed by the membrane in such a way that only test fluid or components of the test fluid can escape from the interior (20) through the membrane (25) to the outside. Test leak device (10) according to claim 1, characterized in that the carrier element (42) is designed as a flange, which preferably The test leakage device (10) is designed to be attached to a complementary counter flange of a test chamber such that test fluid from the interior passes through the membrane and the flange connection directly into the interior of the test chamber. A test leakage device (10) according to claim 1 or 2, characterized in that the support element (42) has fastening devices arranged concentrically around the outlet channel (44) for attachment to the housing (11). A test leakage device (10) according to any one of the preceding claims, characterized in that the fastening devices are screw holes (40) which, in the attached state of the support element, are aligned with corresponding threaded openings (46) in the housing such that a screw (48) can be screwed through each screw hole into a corresponding threaded opening.Test leakage device (10) according to one of the preceding claims, characterized in that, in the fixed state of the support element (42), a sealing ring (50) surrounding the through-opening in a top view is arranged between the support element and the housing (11). Test leakage device (10) according to the preceding claim, characterized in that the sealing ring (50) is metallic. Test leakage device (10) according to one of the preceding claims, characterized in that the membrane (25) is a disc covering the outlet channel (44) and is arranged in a recess surrounding the outlet channel in the support element (42). Test leak device (10) according to one of the preceding claims, characterized in that the test leak device does not have a separate filling opening for filling the interior (20) with test fluid, so that the interior (20) can only be refilled with test fluid through the through-opening (22). Test leak device (10) according to one of the preceding claims, characterized in that the support element is covered by a cover cap (52) connected to the housing. Method for filling a test leak device according to one of the preceding claims, characterized by the steps: Loosening the fastening of the support element to the housing and removing the membrane element from the through-opening (22), Filling the interior (20) through the through-opening (22) with test fluid, and Attaching the support element to the housing such that the through-opening (22) is closed by the membrane element (24) in such a way that only test fluid or components of the test fluid can escape from the interior (20) through the membrane to the outside. The method according to claim 10, characterized in that the support element, in the form of a flange, is attached to a complementary counter-flange of a test chamber such that test fluid from the interior passes through the membrane and through the flange connection directly into the interior of the test chamber.

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