Gas leak detector

Abstract

A gas leak detector provides improved detection of any leaking LPG (liquefied petroleum gas) vessel. Disclosed herein is a gas leak detector (100) for detecting gas leaks from a gas vessel valve unit (111) and / or between the gas vessel valve unit (111) and the gas cylinder (104) and / or through the wall or joint of the gas vessel (104). The gas leak detector has a housing (106) that is movable relative to an external surface (107). The housing (105) has a top (112), a bottom (114) and sides (113), the top (112) and bottom (114) being movable relative to each other. The gas leak detector (100) also has an air flow generator (160) for providing and moving a mixture of air and any leaking gas within a closed loop to improve detection of gas leaks.

Description

TECHNICAL FIELD

[0001] The present invention relates to a gas leak detector, and in particular to a gas leak detector for detecting a gas, such as liquefied petroleum gas, leaking from a gas container, such as an LPG cylinder. BACKGROUND

[0002] Filling containers with one or more gases is a common task in packaging gases, for example for transport or storage purposes. In the field of filling containers with a gas, such as liquefied petroleum gas, also referred to as LPG, filling systems and / or transport systems with a carousel and a disc conveyor are often used.

[0003] To ensure that gas containers do not leak, one or more gas leak detectors are usually provided in such systems. In the event of a gas leak from a gas container being detected, that particular container is automatically or manually sorted out. Since there is a fire and / or explosion hazard in such an environment, all operations are provided in a particularly safe manner to prevent any sparks from being generated.

[0004] These types of gas filling systems with leak detection are used to fill hundreds or even thousands of containers with LPG per hour and to perform leak detection.

[0005] FR 2785049 discloses gas cylinders arriving at a platform 1 and positioned on an axis ZZ. A bell 6 covers the head of the bottle, and after an air flush 10, 62, further air and any gas passes through a valve 19 to an infrared absorption analyser 141. Finally, the valve opens and a pressure drop sucks the remaining air and gas through the analyser. An electronic unit 142 interprets the results and sends a signal to a module 5 which controls the subsequent bottle path.

[0006] FR 2764978 discloses a system for detecting gas leaks from gas cylinders and valves, which comprises a movable cover for enclosing the valve assembly. An infrared sensor is provided which is sensitive to the presence of gas contained within the cylinder. It is connected to a conduit leading from the cover around the valve assembly, enabling a sample of the gas within the cover to be taken. In addition to the infrared detector, there is a means to force gas through the conduit, from the movable cover, past the infrared sensor and into the atmosphere. At least part of the delivery conduit is reduced in diameter in order to ensure that the gas flow velocity exceeds 10 metres per second. A conduit diameter of 5mm or less can be chosen to achieve a gas flow velocity of 20 to 70 metres per second.

[0007] FR 2458064 A1 discloses that a leak in a cylinder of liquefied gas, such as propane or butane, is detected, in particular in the area of the cock assembly. This is performed by using an infrared analyser and an indicator gas. The gas cylinder is placed on a conveyor belt and moved to a leak test station, where a bell-shaped assembly fixed to a vertical jack shaft is lowered onto the cylinder. A supply pipe is attached to an indicator gas source via a distributor. A second inlet is attached to a collar near the lower opening to communicate with a spacing chamber. A flow restrictor controls the flow in the supply pipe. A series of breathers communicate with a pump and are connected to a gas analyser, wherein an infrared detector is coupled to an alarm indicator.

[0008] A gas leak detection system is also known, in which pressurized gas inside a gas cylinder and a leak to the outside are detected, as described below. The gas leak is detected by moving at least a major part of the cylinder through a water bath and detecting whether any bubbles occur, which are caused by the gas leak. Therein, it can be difficult to detect which gas cylinder has a leak, since a certain amount of cylinders has to be moved through such a water bath, such as 1200-1800 cylinders per hour. Typically, the leaks detected with these water baths are leaks through openings in the material of the cylinder wall and / or through the weld seams in the cylinder, such as due to corrosion of the lower end of the cylinder.

[0009] It has been found that the prior art systems are not able to ensure that any gas container that is leaking is detected in a timely manner, while also taking into account factors such as the filling and leak detection capacity of such a system.

[0010] It has also been found that in the known systems, it is difficult to clean the enclosure to expel residual gas from the enclosure before testing the next gas container. This will lead to false test results, in which a gas container is found to be leaking even though it is not, because the gas residue in the enclosure from a previous test leads to a false positive result.

[0011] The inventors of the present invention have realized that an improved gas leak detector and method of detecting a gas leak would be beneficial and have thus designed the present invention. SUMMARY

[0012] It can be considered an object of the present invention to provide an improved gas leak detector and method of detecting a gas leak. Preferably, the present invention alleviates, mitigates or eliminates one or more of the above-mentioned disadvantages or other disadvantages singly or in any combination.

[0013] Thus, the gas leak detector is for detecting a gas leak from:

[0014] a first type of gas leak from a valve unit of a gas container, and / or

[0015] a second type of gas leak between the valve unit of the gas container and the gas container, and / or

[0016] a third type of gas leakage through the wall or joint of the gas container,

[0017] The gas leakage detector comprises:

[0018] - a housing, which is movable to at least partly enclose the gas container and / or the gas container valve unit, the housing comprising means for providing a closed connection between the housing and an external surface to form a substantially closed space, such that a first and / or a second and / or a third type of gas leakage from the gas container and / or the gas container valve unit leaks into the closed space,

[0019] - detection means for detecting the first and / or second and / or third type of gas leakage,

[0020] - an air flow generator for moving a mixture of air and any leaking gas to the detection means.

[0021] In a preferred embodiment, the housing further comprises a top portion, a bottom portion and side portions, and the side portions connect the top portion and the bottom portion.

[0022] Thus, an improved gas leakage detector is provided. One possible advantage of providing a gas leakage detector as described herein is that any leaking gas container can be detected in time, while even further improved leakage detection capabilities can be achieved compared to known systems.

[0023] The substantially closed space, or in fact the closed space, can be understood as a closed space formed within the housing and within a part of the closed loop (e.g. an external gas-tight conduit connected to the housing).

[0024] If any gas leakage occurs, the air flow generator provides a mixture of existing air and leaking gas by means of the air flow. Thus, an amount of leaking gas will be part of the mixture and thus cannot be “hidden” within the housing.

[0025] The air flow generator improves the mixing of air and possible leaking gas, thereby providing a mixture of air and leaking gas. The air flow generator moves the mixture of air and leaking gas to establish a circulation of the mixture of air and leaking gas in the gas-tight closed loop. Thus, the air flow generator moves at least a part of the volume of the mixture of air and leaking gas to the detector.

[0026] In particular, this is beneficial when the mixture of air and any leaking gas is moved through the detection means by means of the air flow generator.

[0027] Alternatively or additionally, this can be seen as an advantage of the present invention, which is based on the understanding disclosed herein that the described solution improves the detection, since no air is added from the outside that creates turbulence inside the enclosure and / or in the closed loop. Such air can reduce the concentration of the gas leak inside the enclosure and / or can even force at least part of the leak out of the enclosure.

[0028] It should be understood that the detection device can comprise means for emitting and / or receiving light, such as infrared light, and / or sound signals, and thereby comprise output and receiving means. Such means can be built-in in a combined emitting / receiving unit. Furthermore, it should be understood that reflecting means, such as mirrors, can be used and arranged in the enclosure in order to reflect the signals within the enclosure. The reflecting means can be arranged in order to utilize the combined unit and / or in order to increase the length of the signal propagation within the enclosure before the signal is received.

[0029] As an example, a first type of pressurized gas leak from the gas container valve unit can be due to a faulty valve. A second type of leak can be due to a leak at the connection between the valve unit and the material of the container, such as related to threads, a poorly welded or defective weld of a threaded plug, also referred to as valve pad, to the material of the gas container. A third type of leak is typically due to corrosion of the bottom of the gas container, for example at the location where the bottom ring is attached to the gas container, and can also be due to a poorly leaking joint, such as a leaking weld or other type of leaking joint. The container can be made of steel, but can also be made of various different composite materials suitable for the marked LPG.

[0030] The outer surface is a surface against which the enclosure can be substantially closed in order to at least enclose the gas container valve unit.

[0031] The advantage of keeping the air / gas mixture in the closed loop is that when no air or gas is added to the mixture from the outside, only gas leaking from the gas container is added to the air / gas mixture in the closed space and the closed loop. Furthermore, no air or gas leaves the closed loop. This results in that when gas leaks, the concentration of gas in the closed loop will increase as more and more gas leaks from the gas container. Thus, the detection device will detect the increased amount of gas in the air / gas mixture, emphasizing that the detector is registering a leak and not just possible residual gas from a previous test.

[0032] The closed loop refers herein to a loop into which gas can be forced, but under normal circumstances, any gas is substantially not allowed or unable to exit. The gas that is forced into the substantially closed loop can for example be the gas itself that is squeezed out of the gas container due to the pressure in the gas container, but additionally or alternatively, also a relatively small amount of air, such as cleaning or purging air that has not been closed off.

[0033] By circulating and continuously mixing the air and the leakage gas by means of the gas flow generator, the detector will measure a continuous increase in the gas concentration as a function of time, so that a possible leakage can be detected as a function of the rate of change of the measured gas concentration and / or as a function of the measured gas concentration at a given time, such as the maximum test time.

[0034] According to an embodiment, the gas-tight closed loop comprises a loop connected to the housing, so that the mixture of air and leakage gas can be circulated via a fluid passage of the loop.

[0035] The fluid passage is closed and gas-tight, so that gas cannot leave the loop between the inlet and the outlet of the loop. Thus, the loop is a closed loop in the sense that gas cannot leave between the inlet and the outlet.

[0036] The loop, such as a gas-tight conduit, e.g. a tube, can be connected to the housing via a gas-tight connection, which provides a fluid connection from / to the housing and the loop. The inlet of the loop can be connected to the housing at one location, such as an upper part of the housing (when in a normal upright position during use), and the outlet can be connected to the housing at a different location, such as a lower part of the housing. The loop can be arranged outside the housing, i.e. connected to an outer part of the housing, and can be arranged to move the mixture of air and leakage gas from one location to another location of the housing.

[0037] According to an embodiment, the loop comprises the detection device and / or the gas flow generator. Advantageously, the detection device and / or the gas flow generator can be placed in an outer part of the loop. For example, the detector can be placed in the outer part to facilitate electrical connections. The gas flow generator can also be placed in the outer part of the loop, or between the loop and the housing. It will be appreciated that the loop can comprise several loop elements, wherein each loop element can comprise a detector and a gas flow generator, respectively.

[0038] In some embodiments of the application, the outer surface is a surface of the gas container. In these embodiments, the outer surface can be a surface part of the gas container, which is in close proximity to the valve unit. Thus, the housing can enclose at least the valve unit in order to detect at least the first type of leakage. When the housing has e.g. a larger diameter, the housing can enclose the valve unit and the surface part of the gas container, where the valve unit is connected to the gas container, so that the second type of leakage can also be detected.

[0039] The means for providing a substantially closed connection can comprise a housing provided with a substantially air-impermeable flexible material around an opening of the housing, the opening preferably being located at the bottom of the housing. The flexible material will come into contact with an external surface, such as the surface of the gas container next to the valve unit, when any leakage of the gas container is detected. Alternatively or additionally, the means for providing a substantially closed connection can comprise a surface formed in the bottom of the housing so as to fit against an external surface, and to form a substantially closed space when the bottom of the housing is moved towards the external surface.

[0040] Thus, according to embodiments of the present application, the means for providing a substantially closed connection can comprise that the shape of the opening in the bottom of the housing is adapted in structure to fit and enclose the surface portion of the gas container provided next to the valve unit. Alternatively or additionally, the means for providing a substantially closed connection can comprise that the bottom of the housing is provided with a substantially air-impermeable flexible material around the opening. Such a flexible material will preferably come into contact with the surface of the gas container next to the valve unit when any leakage of the gas container is detected.

[0041] The same type of structural adaptation of the bottom of the housing and / or the same way of providing a flexible material can be provided when the external surface is a support plate for the container.

[0042] When the size of the housing is adapted to be able to enclose at least the upper part and the side of the gas container, and thus possibly the entire gas container when fitted against an external surface, one can detect one or more of the first, second and third types of leakage at one time. In such embodiments, the external surface can be a support plate, such as a steel plate, for the gas container, for supporting the gas container during the detection, and for the relative movement of the bottom of the housing in order to form a substantially closed space within the housing.

[0043] When the housing is in a closed connection with an external surface, the closed space, such as the closed space in the housing, the detection means and the air flow generator are part of an air-tight closed loop, whereby the air flow generator circulates a mixture of air and leaked gas in the closed loop.

[0044] According to embodiments of the present application, the gas leakage detector further comprises a support plate for supporting the gas container and a flushing fan blowing fresh air into the space above the support plate when the housing is not in a closed connection with an external surface.

[0045] The space above the support plate is the space in which the closed space in the enclosure is located when the enclosure is connected to the support plate. A purge fan is added to blow fresh clean air into the space above the support plate, which further reduces the time for residual gases from previous tests to exit this space. The purge fan blows clean air into the space above the support plate through an outlet in the support plate, ensuring that residual gases are quickly blown away from the test area above the support plate before a new test on another container is started, thus reducing the time.

[0046] When the enclosure is separated from the support plate, the purge fan starts blowing air above the support plate, and when the enclosure is connected to the support plate, the purge fan stops blowing air above the support plate. This can be achieved by switching the purge fan on and off. A disadvantage of this approach is that the start and stop of the purge fan takes a little time. Alternatively, and preferably, a valve can be provided between the purge fan and the air outlet. Then, when the enclosure is separated from the support plate, the valve is immediately opened to allow air to be blown above the support plate immediately. Also, when the enclosure is connected to the support plate, the valve is closed, immediately stopping the air flow above the support plate to avoid adding more air to the air / gas mixture in the closed loop, thus avoiding diluting the mixture. This valve will be able to quickly stop or start blowing air into the space above the support plate in a controlled manner.

[0047] According to embodiments of the present invention, the detection device and / or the airflow generator are located outside the enclosure, and the detection device and / or the airflow generator and / or the diffuser are provided in a loop, such as a closed loop, connected to the enclosure, such as the closed space, thus forming a closed loop.

[0048] Providing the detection device and the airflow generator outside the enclosure provides more flexibility. The detection device and the airflow generator can be used with different enclosures, and have more flexibility by replacing the airflow generator or the detection device.

[0049] According to embodiments of the present invention, the mixture of air and any leaking gas is returned to the enclosure through the diffuser.

[0050] In some embodiments of the present invention, the detection device and the gas leak detector are provided in a closed loop outside the enclosure. The closed loop is connected to the closed space in the enclosure, and is configured such that no air or gas from the outside is able to enter the closed loop or the closed space during operation. The closed space and the closed loop together form a closed loop. The airflow generator circulates the air / gas mixture in the closed loop. The air / gas mixture is circulated from the closed space in the enclosure through an outlet in the support plate to the detection device, which is an analyzer that analyzes the air / gas mixture to detect the presence of a gas in the mixture. The air / gas mixture from the detection device re-enters the closed space in the enclosure through the diffuser, completing the circulation in the closed loop.

[0051] Advantageously, the diffuser can be formed in such a way that it spreads the incoming air / gas mixture as much as possible to create a certain turbulence in the upper part of the housing. Spreading the incoming air / gas mixture ensures that there are no unventilated areas in the upper part of the housing, avoiding pockets of air hiding in the corners of the housing.

[0052] According to an embodiment of the invention, the detection means and / or the gas flow generator are located inside the housing, and the detection means and / or the gas flow generator form a closed loop together with the closed space inside the housing.

[0053] In an alternative embodiment, the detection means and the gas leak detector can be arranged inside the housing, whereupon the closed loop will be located inside the housing, and there can be no closed loop connection means from outside the housing to the closed loop. This allows a compact arrangement without the need for connecting external components to the housing.

[0054] In the event of a detected leak in response to a signal (change) from the detection means, it can be possible to perform data analysis, for example according to threshold values or the like (for example by means of a control system), to classify a given gas container for further inspection, possible repair or controlled emptying and disposal.

[0055] According to an embodiment of the invention, the bottom of the housing is movable relative to the top of the housing.

[0056] According to an embodiment of the invention, the side of the housing is fixed to the bottom and / or the top by means of a solid fixture forming a gas-tight seal.

[0057] The solid fixture can be a clamping ring, or it can be made of glue or of some kind of joint. The solid fixture can be formed using heat or other chemical means. The main issue is that the fixture is gas-tight so that no air or gas can pass between the side and the top or bottom.

[0058] According to an embodiment of the invention, the side of the housing and the bottom of the housing are made in one piece, or the side and the top are made in one piece.

[0059] According to an embodiment of the invention, the side is at least partially formed of a flexible material, such as rubber, synthetic rubber, PVC or other flexible material, which can be stretched or folded to at least partially enclose the gas container.

[0060] Having a flexible enclosure with flexible sides between the top and the bottom has the advantage that when the test is finished, the bottom can be quickly released from the outer surface and lifted upwards. This allows the air / gas mixture in the enclosure to quickly escape from the space in the enclosure so that the gas residue can quickly leave, making the gas detector ready for testing a new gas container.

[0061] According to embodiments of the present invention, the sides can be moved, stretched or extended to cover varying distances between the top and the bottom.

[0062] In cases where the sides are made of a flexible and possibly elastic material, the sides of the enclosure can be stretched or folded longer or shorter as needed.

[0063] Typically, when the bottom is connected to the outer surface, the sides can be slack and wrinkled, then by moving the top upwards, the sides are stretched and become smooth and narrow, thus eliminating possible obstacles that create air resistance, ensuring free passage of the gas flow through the enclosure.

[0064] In order to reduce stress and tension on the sides, it is preferable to keep the sides in a state in which they are not stretched when moving the bottom towards the outer surface, and to stretch the sides only by moving the top upwards after the bottom is coupled to the outer surface. This increases the life of the enclosure, so that more tests can be performed using the enclosure before it needs to be replaced.

[0065] According to embodiments of the present invention, the sides are formed at least partially from a telescopic arrangement in which two or more tubes are sealed against each other and can be adjusted axially into each other so that the sides can be extended to at least partially enclose the gas container.

[0066] The advantage of the telescopic embodiment is that the individual tubes are not bent or stretched in any way and therefore do not wear or tear and shorten their life, they just move up and down.

[0067] According to embodiments of the present invention, the sides are formed at least partially from a bellows device that can be moved to at least partially enclose the gas container.

[0068] According to embodiments of the present invention, the sides are formed at least partially from a tube that can be moved to at least partially enclose the gas container.

[0069] The tube or other tubular element can be moved when the top is stationary or when the top is moved. Advantageously, a solution in which the sides can be moved independently of the top (which can be moved separately or fixed) provides a simple structure that facilitates the replacement of the gas container.

[0070] An advantage of the tube embodiment is that the tube is not strained in any way and thus does not wear or tear and shorten its life, it just moves up and down, or the top moves up and down inside the tube. Having fewer movable parts makes the tube embodiment less exposed to wear and tear.

[0071] According to embodiments of the present invention, the gas leak detector further comprises a separate test unit, which is able to be arranged around the gas container valve unit to detect gas leaks from the gas container valve unit.

[0072] The separate test unit comprises a gas detection sensor and possibly also a fan to circulate the air / gas mixture in the separate test unit. The separate test unit is lowered over the gas container valve unit to form a gas tight connection with the surface of the gas container, so that gas leaking from the valve unit or from between the gas container valve unit and the gas container is contained in the separate test unit. An advantage is that the separate test unit is able to detect gas leaks from the valve unit and it is clear that the leak is from the valve unit and not from another part of the container.

[0073] According to embodiments of the present invention, the side part of the housing is movable relative to the bottom part and / or the top part. The side part is connected to the bottom part and / or the top part by a seal, which forms a gas tight connection, but allows the side part to move relative to the bottom part and / or the top part.

[0074] According to embodiments of the present invention, the bottom part of the housing comprises means for providing a closed and sealed connection between the housing and the external surface when the bottom part is moved relative to the external surface, in order to form a closed space within the housing.

[0075] According to embodiments of the present invention, the top part is moved by a first moving mechanism.

[0076] According to embodiments of the present invention, wherein the bottom part is moved by a second moving mechanism, the second moving mechanism provides means for moving the bottom part from an initial position to a position in contact with the external surface.

[0077] According to embodiments of the present invention, the top part and the bottom part are moved simultaneously, either in parallel or at different speeds.

[0078] It is also possible to move both the top part and the bottom part using the first moving mechanism or the second moving mechanism, so that the top part and the bottom part are moved in parallel. An advantage of moving the top part and the bottom part in parallel is that no stress or wear is created on the side part during the movement, which maintains the same shape. Another possibility is to move the bottom part faster than the top part when the bottom part is moved away from the external surface, but still move the top part as fast as possible. An advantage is to have the housing in a position as far away from the external surface as possible, to maximize the flushing speed of the space above the external surface.

[0079] According to embodiments of the present application, the first and / or second moving mechanism moves the top and / or the bottom to stretch the side portion to form a substantially narrow closed connection between the top and the bottom.

[0080] According to embodiments of the present application, the outer surface is a support plate for supporting the gas container in use of the gas leak detector, or the outer surface is a surface portion of the gas container provided with the valve unit.

[0081] According to embodiments of the present application, the detection device and / or the gas flow generator are connected to the housing by the support plate.

[0082] In particular, the pressurized gas within the gas container is a gas heavier than air, such as a liquefied gas, in particular liquefied petroleum gas (LPG).

[0083] In embodiments of the present application, the gas flow generator comprises one or more fans, each fan having one or more fan blades. In preferred embodiments, the fan is an air-driven fan, i.e. a fan driven pneumatically, wherein the force for driving the fan is provided by an air-driven turbine.

[0084] According to an aspect of the present application, there is provided a method for detecting a gas leak, the gas leak being a first type of gas leak from a valve unit of a gas container, and / or a second type of gas leak between the valve unit of the gas container and the gas container, and / or a third type of gas leak through a wall or a joint of the gas container, wherein the gas leak detector comprises:

[0085] a housing, the housing being movable to at least partially enclose the gas container and / or the valve unit of the gas container, the housing comprising means for providing a closed connection between the housing and an outer surface to form a closed space within the housing, such as a closed space within the housing, such that the first and / or second and / or third type of gas leak from the gas container and / or the valve unit of the gas container leaks into the closed space,

[0086] a detection device for detecting the first and / or second and / or third type of gas leak, the detection device being either located in the closed space in the housing, or being located in a closed loop connected to the closed space,

[0087] a gas flow generator for moving a mixture of air and any leaked gas to the detection device, the gas flow generator being either located in the closed space in the housing, or being located in a closed loop connected to the closed space,

[0088] wherein the method for detecting a gas leak comprises:

[0089] providing a gas container,

[0090] - providing a closed connection between the enclosure and the outer surface such that the closed space, the detection means and the airflow generator are part of a gas-tight closed loop, and

[0091] - using the airflow generator to circulate at least a part of the volume of the mixture of air and leaked gas within the gas-tight closed loop.

[0092] According to an aspect of the present invention, the method for detecting a gas leak further comprises:

[0093] - moving the enclosure relative to the outer surface to at least partially enclose the gas container, and

[0094] - providing a closed connection between the enclosure and the outer surface when the bottom of the enclosure is moved relative to the outer surface to connect the enclosure to the outer surface to form a closed space, and to make the closed space, the detection means and the airflow generator part of a gas-tight closed loop,

[0095] - using the airflow generator to circulate the mixture of air and any leaked gas within the closed loop, and

[0096] - detecting a first and / or a second and / or a third type of gas leak with the detection means, the detection means being provided within the closed loop in case of any gas leak within the closed loop.

[0097] According to an aspect of the present invention, the method for detecting a gas leak further comprises flushing the fan to blow fresh air into the space above the support plate to disperse any remaining gas when the enclosure and the outer surface are not in closed connection.

[0098] Hence, an improved method for detecting a gas leak is provided. Possible advantages of the method stem from the description relating to the gas leak detector and / or other description. Hence, advantages or benefits described in relation to the device aspect also apply to the method aspect. In particular, how the device is operated as described above also applies to the method aspect of the present invention, and method claims of such embodiments are contemplated in the context and wording presented and used herein, e.g. in the above summary in relation to the device aspect.

[0099] Before step b), the enclosure can be purged with substantially clean air, e.g. to prevent any remaining leaks from a previous gas container detection to be present in the enclosure.

[0100] Generally, by stating "advantages" or benefits or similar in relation to the present invention and with reference to the present invention, it must be understood that the advantages can be seen as possible advantages provided by the present invention, but it should also be understood that the present invention is particularly advantageous, but not the only advantageous, to obtain said advantages.

[0101] In general, the various aspects of the application, i.e. the devices and methods of the application and the advantages can be combined and coupled in any way possible within the scope of the application.

[0102] These and other aspects, features, and advantages of the present application will be described with reference to embodiments described below, and will become apparent from the description. BRIEF DESCRIPTION OF DRAWINGS

[0103] Embodiments of the application will be described, by way of example only, with reference to the drawings in which:

[0104] Figure 1 is a side view of a gas leak detector,

[0105] Figure 2 is a gas leak detector with a gas flow loop when the housing is in an open position,

[0106] Figure 3 is a gas leak detector with a gas flow loop when the housing is in a closed position,

[0107] Figure 4 is an embodiment of the housing wherein the sides of the housing are made of a flexible material,

[0108] Figure 5 is an embodiment of the housing wherein the sides of the housing are in a telescopic arrangement,

[0109] Figure 6 is an embodiment of the housing with a separate test unit for detecting a gas leak from a valve unit of a gas container,

[0110] Figure 7 is an embodiment of the housing wherein the sides of the housing are tubes that are movable and not fixed to the top of the housing,

[0111] Figure 8 is a diagram showing the increase of gas in a closed loop during a gas leak. DETAILED DESCRIPTION

[0112] Figure 1 is a side view of a gas leak detector 100. The gas leak detector 100 can be included in a gas filling system for filling a gas container. The leak detector 100 is generally used to detect whether a gas container 104 filled with a gas under pressure, such as liquefied petroleum gas (LPG), has a gas leak.

[0113] At the top of the gas container 104 is a valve unit 111 for filling the container 104 with gas, or for letting gas out of the container 104. A shroud 148 protects the valve unit 111.

[0114] Leakages can come from the container valve unit 111 and / or from components such as plugs between the gas container valve unit 111 and the gas container 104 and / or from the gas container 104 itself such as the location where the base ring 102 is attached to the container 104 or where different parts of the gas container 104 are joined together by joints 149 or from any part of the gas container 104.

[0115] Generally, the system works automatically and includes the location where also filling of the gas containers and sorting out any or those having one of the mentioned first, second and / or third type of leakages is performed.

[0116] The shown gas leakage detector 100 can be part of a complete transport system for gas containers in a transport gas container filling system and / or a gas leakage detection system. In the shown embodiment, the leakage detector 100 is provided for gas containers to be transported to the location of the gas leakage detector. Alternatively, a gas leakage detector is installed on each transport unit in the transport system in order to detect any gas leakage over an extended detection period compared to transporting the gas container to the location of the gas leakage detector. Alternatively, several independent leakage detection stations or systems can be provided in order to extend the detection time and / or increase the capacity.

[0117] The drawing shows a gas leakage detector 100 for detecting gas leakage from a gas container valve unit 111 of a first type of gas leakage 101 and / or between the gas container valve unit 111 and the gas container 104 of a second type of gas leakage 103 and / or through a wall or weld or joint in the gas container 104 of a third type of gas leakage 105. The third type of gas leakage is typically in a lower part of the gas container 104 as shown in the drawing, such as at the attachment of the base ring 102 of the gas cylinder as shown in the drawing, where the base ring 102 is welded or otherwise joined to the gas container 104. Further, the third type of gas leakage 105 can occur from the joints 149 when the gas container 104 is made of more parts that are joined together. The gas container is typically made of metal or of a composite material. The third type of leakage 105 from the gas container 104, especially if the gas container 104 is of a composite material, can also occur at any location of the surface of the gas container 104.

[0118] As shown, the gas leakage detector 100 comprises a housing, in this embodiment a housing 106, which can be moved horizontally and relative to an external surface, in this embodiment a support plate 109, in order to at least partly enclose the gas container valve unit 111. This movement is indicated with a double headed arrow 139.

[0119] The housing 106 comprises a top portion 112, a side portion 113 and a bottom portion 114. The side portion 113 of the housing is secured to the bottom portion 114 and the top portion 112 with a secure clamp forming an airtight seal. The secure clamp can be a clamping ring or glue or a weld seam or any other joining means forming an airtight seal capable of maintaining a pressure difference between the inside and the outside of the housing.

[0120] The top portion 112 and the bottom portion 114 can be moved up and down by a first moving mechanism 135 moving the top portion 112 and a second moving mechanism 136 moving the bottom portion 114.

[0121] Furthermore, Figure 1 A closed loop 126 is shown connected to the housing 106 through an outlet 110 in the support plate 109 and a diffuser 128 in the top portion 112. There is a closed space 127 in the housing. The closed space 127 forms a closed loop together with the closed loop 126, the outlet 110 and the diffuser 128 in which the air / gas mixture circulates.

[0122] The closed loop 126 or positive loop can be understood as a closed loop providing a closed, i.e. airtight, fluid connection between the two openings of the housing 106. Thus, it is understood that the housing 106 forms with the loop 126 a substantially closed space 127. The loop 126 can comprise or consist of a tube, such as a rigid metal tube, a flexible rubber tube, including combinations thereof, or other conduit arranged to transport air and any possible gas leak.

[0123] That is, the closed space 127, comprising the space inside the housing 106 and the space inside the loop 126, is closed, or substantially closed, in the sense that it is a space into which gas leak from the gas container 104 can be forced, but any gas is substantially not allowed or cannot exit the space. The term "closed" or "substantially closed" used in connection with the closed space 126 is to be understood as that a small amount of gas or air can escape, for example due to a slight leak, such as a leak in the seal between the housing and the outer surface. In case of a gas container leak, such a slight leak has only a negligible effect on the increase in gas concentration in the closed space 127 over time.

[0124] Similarly, an airtight closed loop or a substantially airtight closed loop is to be understood as that a slight leak can exist, however, such a slight leak has only a negligible effect on the concentration of gas leak.

[0125] Alternatively, and technically equivalently, the closed space 127 is defined by a closed or substantially closed space inside the housing 106, in the sense that any gas is substantially not allowed or cannot exit the housing except at the fluid connection with the loop 126.

[0126] The control unit 108 controls the movement of the first and second movement mechanisms 135, 136.

[0127] Obviously, when the top 112 is movable, the connection between the closed loop 126 and the diffuser 128 is generally flexible, such as by a hose, in order to allow the top 112 to move.

[0128] In Figure 1 The embodiment shown is an embodiment with a flexible side 113. Of course, any other embodiment of a housing mentioned hereinafter or otherwise allowing the top and bottom to move relative to each other can also be used.

[0129] The housing comprises means (not shown in detail) for providing a substantially closed connection between the housing 106 and the external surface 107 when the housing is moved relative to the external surface, in order to form a substantially closed space within the housing. In the figures, the housing is shown to be moved, which is preferred. However, the support plate can additionally or alternatively also be moved upwards, such that by using the movement means to move the housing and / or vice versa towards the external surface, the housing can be connected to the gas container.

[0130] In the figures, a cylindrical housing 106 is shown, but it will be understood that the housing can have any form, as long as it has an opening that fits around the container, and as long as it is able to form a substantially closed space when connected to the support plate 109.

[0131] Reference is made here to a gas container 104. However, a gas container is a gas bottle or gas cylinder as shown in the figures. These containers are standardized containers for storing gas, such as propane gas or LPG in liquid form, for example for industrial use or for use in a home, for supplying gas to cookers, heaters and other devices. The weight of a gas container when empty is approximately 2.5 to 50.0 kg, and when full approximately 5.0 to 100.0 kg. The height of such a gas container is generally approximately 150 mm to 1500 mm. The diameter or width of a gas container is generally approximately 150 mm to 400 mm.

[0132] Figure 2 and Figure 3 Different stages in the gas detection process are shown. In Figure 2In this phase, the space above the support plate is being purged. The enclosure 106 is opened and the bottom 114 of the enclosure is moved away from the support plate 109 to allow gas from the space in the enclosure 106 between the support plate 109 and the top 112 to exit the space. This is achieved by blowing fresh, clean air through the outlet in the support plate 109 into the space above the support plate 109, blowing away any residual leakage gas from the space to avoid false results in the next test. Fresh air is also blown out from the diffuser 128 through the closed loop 126 to disperse possible gas residues from the upper part of the enclosure 106. Fresh air enters the system through a valve 129; the valve 129 is open during the purge but closed during the leakage detection. A purge fan 131 blows fresh air into the loop.

[0133] Figure 3 is the detection phase. The enclosure is now closed. The gas container 104 is placed inside the enclosure 106 and the enclosure is closed by moving the bottom 114 of the enclosure into a closed, sealed connection with the support plate 109, thereby creating a closed space 127 inside the enclosure 106. The valve 129 connected to the purge fan 131 is closed so that fresh air cannot enter the loop. The air flow generator 160 circulates the air / gas mixture in the closed loop and drives the air / gas mixture through the detection device 130. The air / gas mixture is circulated from the closed space 127 in the enclosure 106 through the outlet 110 to the air flow generator 160 and the detection device 130 and further to the diffuser 128 and back into the closed space 127 in the enclosure 106.

[0134] A leak in the air-tight closed loop can result in false test results, as leakage of gas from the gas container 104 can at least partly dissipate into the surrounding environment via the leak, resulting in a test showing that the gas container 104 does not leak gas. Such a leak can be caused by a faulty connection between the loop 126 and the inlet of the top 112, an insufficient or faulty seal between the bottom 114 and the outer surface 107, such as the support plate 109, and other leaks.

[0135] According to an embodiment, the gas leak detector 100 is configured with a pressure detector arranged to detect any leak in the closed loop. Thus, a leak will result in a pressure drop that the pressure detector can detect. Typically, the pressure increases downstream of the air flow generator 160 during the test. Thus, the pressure sensor can be located anywhere downstream of the air flow generator 160 and advantageously upstream of the inlet of the top 112, such as between the air flow generator 160 and the detection device 130.

[0136] During the transition from the flushing phase to the test phase, the flushing fan 131 blows fresh air into the circuit 126 via the valve 129. Due to the sealed connection between the bottom 114 and the support plate 109, this results in an increase in pressure that the pressure detector can detect. However, in the event of a leak in the circuit 126, the pressure increase will be smaller.

[0137] Thus, by monitoring the measurement from the pressure detector, it is possible to detect a leak due to the pressure generated by the flushing fan 131 before the test is started, as well as a leak caused by the pressure generated by the gas flow generator 160 during the test.

[0138] In order to determine a leak fault in the gas-tight closed loop, such as a leak fault in the circuit 126, the gas leak detector 100 can comprise a detection controller arranged to determine a leak fault from the measurement from the pressure detector, for example by comparing the measurement to a threshold pressure value.

[0139] Figure 4 An embodiment of the housing 106 is shown, in which the side 113 of the housing is made of a flexible material that can be stretched or folded, such as rubber, synthetic rubber, PVC or other flexible material.

[0140] Figure 5 An embodiment of the housing 106 is shown, in which the side 113 of the housing is a telescoping arrangement, in which two or more tubes are sealed against each other and can be adjusted axially into each other so that the side can be extended to at least partially enclose the gas container.

[0141] Figure 6 An embodiment of the housing 106 is shown, in which a separate test unit 140 is provided for detecting a gas leak from the gas container valve unit 111. The separate test unit 140 can be lowered by a lowering mechanism 142 to form a sealed space around the valve unit 111, to detect the gas in the sealed space, thereby narrowing down the leak to the valve unit 111. The lowering mechanism 142 is located outside the housing 106, while the separate test unit 140 is located inside the housing 106. The separate test unit 140 is connected to the lowering mechanism 142 by a rod 144. The rod 144 passes through the top 112 of the housing 106 and the passage 146 through the top 112 is sealed, for example by an o-ring or other type of suitable seal. The separate test unit 140 comprises a gas detection sensor (not shown) and possibly also a fan (not shown) to circulate an air / gas mixture in the separate test unit 140. The separate test unit 140 is lowered over the gas container valve unit 111 to form a gas-tight connection with the surface of the gas container 104, thereby capturing gas leaking from the valve unit 111 or between the gas container valve unit 111 and the gas container 104 for detection inside the separate test unit 140.Figure 6 The housing is shown with flexible side portions 113, but any different embodiment of side portions 113 can be used.

[0142] Figure 7 An embodiment of the housing 106 is shown, wherein the side portions 113 of the housing are tubes, or wherein at least the inner portions extending along the longitudinal direction of the housing are tubular, like cylindrical shaped. The tubes are fixed to the bottom portion 114, but not to the top portion 112. Thus, the top portion 112 can move like a piston within the side portions 113. The top portion 112 is connected to the side portions 113 by a seal, which forms an airtight connection, but allows the side portions 113 to move relative to the top portion 112.

[0143] Advantageously, Figure 7 The configuration in allows the volume in the housing to adapt to the size of the gas container 104, in order to minimize the volume, and thus the closed space 127, in order to maximize the sensitivity to gas leakage from the gas tank 104.

[0144] That is, for a leaking gas tank with a given leakage rate, a smaller closed volume will maximize the sensitivity, i.e. will reduce the time from the start of the test until the concentration of the leaking gas in the closed volume reaches a threshold concentration of the leaking gas, like a threshold set to define a leaking gas container or a threshold defining a minimum reliably detectable concentration.

[0145] The side portions 113 are movable along the longitudinal direction and in the opposite direction as indicated by the arrows. The top portion 112 can be movable, with the advantages described above, or can be fixed. Whether the top portion 112 is movable or not, Figure 7 The configuration of can be advantageous during the replacement of the gas container 104, because it is only necessary to raise the side portions 113 in order to move the gas tank away, and it is only necessary to lower the side portions 113 to establish the closed space 127.

[0146] In particular, after testing a gas container, the side portions 113 and the top portion 112 can be moved such that the side portions 113 can be effectively flushed when they are open at both ends.

[0147] In an example, after a test of a gas container has been performed, the gas leak detector is configured such that the tank is raised to a level where the seal or the bottom portion 114 is close to or in contact with the top portion 112. In this way, the side portions 113 are effectively flushed by the relative movement between the side portions 113 and the top portion 112.

[0148] In an example, when the test starts, the top portion 112 is lowered until it contacts or is stopped by the top of the gas container 104, like a protruding handle of the gas container. In this way, the closed volume is minimized as much as possible.

[0149] Figure 8 is a graph showing the main advantage of the present application, when the air / gas mixture is circulated in a closed loop, the gas concentration increases over time, wherein no air from the outside is added to the mixture. Thus, only the amount of gas increases over time as more and more gas leaks from the gas container 104. Thus, as the gas ratio in the gas / air mixture increases over time, it can be positively proven that the detected gas is from a leak of the container and not from the residual amount of gas from previous tests.

[0150] Although the present application has been described in connection with the preferred embodiments thereof, it will be apparent to those skilled in the art that it is not intended to be limited to the particular form set forth herein. Rather, the scope of the present application is limited only by the appended claims.

[0151] In this section, for the purpose of explanation and not limitation, certain specific details of the disclosed embodiments are set forth in order to provide a thorough understanding of the present application. However, it will be readily apparent to one skilled in the art that the present application can be practiced without these specific details, and in other embodiments, not all of the details listed herein are required. In addition, in this context, for the sake of brevity and clarity, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to unnecessarily obscure aspects of the present application.

[0152] In the claims, the term "comprising" does not exclude the presence of other elements or steps than those listed in a claim. Further, although various features can be included in different claims, these can advantageously be combined, and the combination of features included in the different claims is not meant to be restrictive of those features. Also, singular references do not exclude a plurality. Thus, references to "one", "a", "an", "first", "second" etc. do not preclude a plurality. Reference signs in the claims are included for clarity and do not limit the scope of the claims.

Claims

1. A gas leak detector for detecting liquefied petroleum gas (LPG) leaks, wherein the leak originates from: - First-class gas leakage (101) from the gas container valve unit (111) of the LPG gas container (104), and / or - A second type of gas leak (103) between the gas container valve unit (111) and the gas container (104), and / or - Class III gas leakage (105) through the wall or joint of the gas container (104). in, The gas leak detector includes: - A housing (106), movable to at least partially surround the gas container (104), the housing (106) including means for providing a closed connection between the housing (106) and an outer surface (107) to form a closed space (127) or a substantially closed space (127), such that a first-class gas leak and / or a second-class gas leak and / or a third-class gas leak from the gas container (104) and / or the gas container valve unit (111) leaks into the closed space (127). - Detection device (130) for detecting Class I gas leaks and / or Class II gas leaks and / or Class III gas leaks, - An airflow generator (160) for moving a mixture of air and any leaked gas to the detection device (130), wherein when the housing (106) is in a closed connection with the outer surface (107), the closed space (127), the detection device (130), and the airflow generator (160) form part of an airtight closed loop or a substantially airtight closed loop, such that the airflow generator (160) circulates at least a portion of the volume of the mixture of air and leaked gas within the airtight closed loop. The airtight closed loop includes a circuit connected to the housing to allow a mixture of air and leaked gas to circulate via a fluid passage in the circuit, and the housing (106) further includes a top (112), a bottom (114) and a side (113), with the side (113) connecting the top (112) and the bottom (114), wherein the bottom (114) of the housing is movable relative to the top (112) of the housing.

2. The gas leak detector according to claim 1, wherein, The circuit is arranged outside the housing.

3. The gas leak detector according to claim 2, wherein, The circuit is arranged to move a mixture of air and leaked gas from one location of the housing to another location of the housing.

4. The gas leak detector according to claim 1, wherein, The gas leak detector also includes a support plate (109) supporting the gas container and a flushing fan (131). When the outer casing (106) is not in a closed connection with the outer surface (107), the flushing fan blows fresh air into the space above the support plate (109).

5. The gas leak detector according to claim 1, wherein, The detection device (130) and / or airflow generator (160) are located outside the housing (106), and the detection device (130) and / or airflow generator (160) and / or diffuser (128) are disposed in a loop (126) connected to the housing (106) to form the closed loop.

6. The gas leak detector according to claim 1, wherein the side portion (113) is at least partially formed of a flexible material, including rubber and PVC, the flexible material being stretchable or foldable to at least partially surround the gas container (104).

7. The gas leak detector according to claim 1, wherein, The side portion (113) is formed at least partially by a nested arrangement, wherein two or more tubes abut and seal against each other and are axially adjustable into each other so that the side portion can extend to at least partially surround the gas container (104).

8. The gas leak detector according to claim 1, wherein, The side portion (113) is at least partially formed by a tube that is movable to at least partially surround the gas container (104).

9. The gas leak detector according to claim 1, wherein, The outer surface (107) is either a support plate (109) used to support the gas container (104) when the gas leak detector is in use, or the outer surface (107) is the surface portion of the gas container (104) on which the gas container valve unit (111) is provided.

10. A method for detecting a liquefied petroleum gas (LPG) leak, wherein the leak originates from: - First-class gas leakage (101) from the gas container valve unit (111) of the gas container (104), and / or - A second type of gas leak (103) between the gas container valve unit (111) and the gas container (104), and / or - Class III gas leakage (105) through the wall or joint of the gas container (104). in, Gas leak detectors include: - A housing (106), movable to at least partially surround the gas container (104), the housing (106) including means for providing a closed connection between the housing and an outer surface (107) to form a closed space (127), such that first-class gas leaks and / or second-class gas leaks and / or third-class gas leaks from the gas container (104) and / or the gas container valve unit (111) leak into the closed space (127). - A detection device (130) for detecting Class I gas leaks and / or Class II gas leaks and / or Class III gas leaks, said detection device (130) being located either in a closed space (127) within the housing or in a closed loop (126) connected to said closed space (127). - An airflow generator (160) for moving a mixture of air and any leaked gas to the detection device (130), the airflow generator (160) being located either in a closed space (127) within the housing or in a closed loop (126) connected to the closed space (127). The method includes: - Provide gas container (104). - A closed connection is provided between the outer casing (106) and the outer surface (107), such that the closed space (127), the detection device (130), and the airflow generator (160) are part of an airtight closed loop or a substantially airtight closed loop, and - Using the airflow generator (160), at least a portion of the volume of the mixture of air and leaked gas is circulated in the airtight closed loop, and The outer casing (106) further includes a top (112), a bottom (114) and a side (113), and the side (113) connects the top (112) and the bottom (114), and the bottom (114) of the outer casing is movable relative to the top (112) of the outer casing.

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