Leak detection device using helium and helium detectors

Abstract

The present invention provides a method and apparatus for detecting leaks in a unit under test. [Solution] A method for detecting leaks in a unit under test includes scanning the SKU of the unit under test, transmitting the SKU information to a computer, connecting the unit under test to a test apparatus, removing gas from the internal space of the unit under test, monitoring the vacuum pressure in the internal space of the unit under test until the vacuum pressure reaches the test pressure, initiating the delivery of helium to the outside of the unit under test through a helium gun by pulling the trigger of the helium gun to dispense helium from the helium gun, positioning the helium supply gun so that helium is released over the welds of the unit under test, detecting the speed at which the helium supply gun moves while dispensing helium, and displaying the helium content inside the unit under test on a graphical user interface.

Description

Technical Field

[0001] Embodiments of the present invention generally relate to leak detection devices useful for detecting leaks from a sealable container including a pipe or piping section, and more particularly to leak detection devices using helium and a helium detector.

Background Art

[0002] A leak detector can be used to evaluate the presence and flow rate or amount of a leak occurring through a weld connecting two sections of a pipe, such as a stainless steel pipe, that are welded together to form a test unit having at least one weld and at least two pipe sections connected by the at least one weld. To conduct the test, generally, a pressure lower than the ambient pressure is formed within the internal space of the test unit by connecting the interior of the test unit to a vacuum pump or to a volume at a desired vacuum level (a desired sub-ambient pressure surrounding the test unit), and then helium is distributed around locations of the test unit where leaks are to be evaluated, such as the welds. A helium detector in a region below ambient pressure fluidly connected to the internal space of the test unit supplies an indication of whether helium has been detected in the sub-ambient pressure environment within the test unit, and in some cases, its concentration or number of atoms.

[0003] Helium leak testing is performed periodically on the geometry of welds used to connect piping to each other, and other fluid conduits surrounding an environment intended to be liquid-tight, using a helium wand that distributes helium from a helium source to determine the presence, and possibly the amount, of helium passing through the welds. Because helium is a very small atom, it can pass through openings in welds that larger gas atoms or molecules cannot pass through due to their size. The amount of helium detected passing through the weld is an indicator of the gap in the weld. This helium leak test is often a manual process, in which a technician or other operator or user connects the internal space of the unit under test, for example, the internal space of the piping including the fittings and the welds within them, to a vacuum source, for example, piping or reinforcing hose connected to a vacuum pump, or for example, a factory vacuum line. The operator or user then takes the helium wand and uses its trigger 210 to activate the helium flow from the helium wand and moves the helium distributing end of the wand over the entire range of the unit under test that is subject to leak testing. For example, if the part of the unit under test being evaluated for leakage is a weld, and a helium detector in the vacuum line indicates the presence of helium in the vacuum line exceeding a preset amount or concentration, the operator or user will determine that the weld has failed the test and has an unacceptable leakage, and the unit under test will be reworked or discarded. In this testing paradigm, if a small amount of helium passes through the weld but is below the threshold amount, it will not be indicated as a defective weld and can be used by the operator to monitor the effectiveness of the welding process that forms the welds connecting the pipes.

[0004] This testing methodology has several limitations. For example, all information regarding the pass or fail status of the unit under test must be recorded manually, and therefore, it is rarely possible to track welds one-to-one against a specific test time or against a specific welding source such as a particular welding operator, welding station, raw materials used to weld the piping, and lots of piping welded together, although all of this information is useful for tracing defects for quality control purposes. In addition, the presence of the appropriate vacuum pressure within the unit under test and the speed at which the helium rod is moved along the weld can affect the validity of the test, thus influencing the test operator or user of the unit under test. This could lead to a false "pass" result for a defective weld. [Overview of the project]

[0005] In one embodiment, the apparatus for detecting leaks in a unit under test includes a helium distributor, which is connectable to a helium gas source to which a motion detector is connected, and is configured to selectively distribute helium; a vacuum source, which is releasably connectable to the unit under test through a fitting; a helium detector, which is fluidly coupled to the vacuum source; and a controller, which is operably coupled to the helium detector and the motion detector and is configured to receive an electrical signal indicating the speed of movement of the helium distributor as helium is distributed from the helium distributor. In another embodiment, a method for detecting a leak in a unit under test includes scanning the SKU of the unit under test, transmitting the SKU information to a compute, connecting the unit under test to a test apparatus, removing gas from the internal space of the unit under test, monitoring the vacuum pressure in the internal space of the unit under test until the vacuum pressure reaches the test pressure, initiating the delivery of helium to the outside of the unit under test through a helium gun by pulling the trigger of the helium gun and dispensing helium from the helium gun, positioning the helium supply gun so that helium is released over the weld of the unit under test, detecting the speed of movement of the helium supply gun while dispensing helium, and displaying the helium content inside the unit under test on a graphical user interface.

[0006] The above-mentioned disclosure may be described in more detail with reference to embodiments, some of which are illustrated in the accompanying drawings, in order to allow for a more detailed understanding of the features of the disclosure listed above. However, it should be noted that the accompanying drawings illustrate only exemplary embodiments of the disclosure and should not be considered limiting in scope, as other equally valid embodiments are permissible. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing the circuit for leak detection testing. [Figure 2]This graph shows the internal pressure of the unit under test, the amount of helium detected, and the measured values ​​over time. [Figure 3] This is a flowchart showing the leak detection test method. [Figure 4] This figure shows a graphical representation of the user interface displaying the results of a leak test. [Figure 5] This figure shows a graphical representation of the user interface illustrating another result of the leak test. [Figure 6] This figure shows a graphical representation of the user interface illustrating yet another result of the leak test. [Figure 7] This figure shows an alternative structure for an accelerometer in leak testing. [Modes for carrying out the invention]

[0008] For ease of understanding in this specification, the same reference numerals are used to designate identical elements common to the drawings, where possible. It is conceivable that elements and features of one embodiment may be usefully utilized in other embodiments without further description.

[0009] Referring to Figure 1, the leak detection system 100 is shown. Here, the leak detection system 100 is configured as follows. a) Supply helium to the location of the unit under test, such as the welding site of the unit under test, under the control of the operator. b) Monitor the vacuum pressure inside the unit under test to prevent the operator from prematurely releasing helium into the weld before the unit reaches the appropriate base vacuum pressure. c) Determine the presence of helium entering the internal space of the unit under test, and optionally, the amount of helium. d) Provide an indication that the unit under test has passed or failed.

[0010] In one embodiment, a controller or programmable computer is provided and operably connected to the following: A vacuum pressure sensor that can determine the vacuum pressure inside the unit under test. A flow controller that determines the helium flow rate. A label reader capable of determining the type and manufacturing lot of the unit under test.

[0011] The computer or controller is further configured to monitor the vacuum pressure and helium flow controller within the unit under test to determine whether the vacuum pressure has reached the appropriate level before helium is distributed to the leak testing area of ​​the unit under test, and whether the operator has exceeded the speed or rate of the helium distributor's distribution area while releasing helium from the helium distributor adjacent to the area of ​​the unit under test where leakage is being evaluated. The computer or controller is also configured to provide pass or fail indicators and to notify the operator of any unsatisfactory tests requiring retesting of the unit under test. Furthermore, System 100 can be used to enable operators, users, or other personnel to track the amount of helium detected in a unit under test, as well as multiple helium leak tests over time on multiple units under test, by type of unit under test, lot number, serial number, or other identifying mark, in order to determine trends in the amount of helium detected. It can also be used to enable weld manufacturers to gain better visibility into process biases or changes, indicated by trends in changes or biases in the amount of helium detected over time on multiple units under test, for root cause analysis aimed at weld integrity and for preventive maintenance to reduce the number of defective welds produced beyond the theme by the manufacturing equipment. In the implementation of System 100 described herein, a power supply 130 is provided, and all power to operate the various motorized components of the system is supplied from the output of the power supply. This makes it possible to load the components of System 100 into racks or other such devices for ease of use and to reduce clutter.

[0012] In the system 100 of Figure 1, a factory helium source is provided, for example, a helium source having an outlet fitting such as a quick connect-disconnect fitting, located adjacent to a test table 103 on which the unit under test 114 can be placed for testing. Alternatively, helium can be supplied in portable or movable bottles, such as bottles on a wheeled cart, or by other mechanisms and / or structures. The helium source 101 is fluidly connected to the input port of a mass flow monitor 102. The mass flow monitor 102 is useful for measuring and monitoring the flow rate, and therefore the amount, of helium flowing through a helium gun 108 to which the monitor is connected. The output port of the mass flow monitor 102 is connected to a two-way coupler 106 by a fluid supply pipe. The two-way coupler 106 consists of a female fitting 104 and a male fitting 105. The fittings are cylindrical hollow metal fixtures, and the female fitting houses a check valve consisting of a spring that presses a ball against a sealing base, allowing helium to flow through the connected female and male fittings 104, 105, which in turn allow the male fitting to be fastened inside the female fitting with a leak-free seal. The male fitting 105 is connected to a fluid piping 107, such as a flexible reinforced hose, which is connected to the base of the helium gun 108.

[0013] Fluid piping 107 supplies helium to the helium gun 108 through a connection at the base of the helium gun, once the male and female fittings 105, 104 of the coupler 106 are connected to each other. The helium gun 108 consists of a body 113 shaped for ergonomic use by the user's hand. Inside the body 113 is a hollow flow conduit extending from piping 107 at the base of the helium gun 108 to a distribution nozzle 111, through which the flow is controlled by a valve (not shown), which is opened by the operator or user of the helium gun 108 pressing down on the gun's trigger 210 and closed by releasing the pressure against the trigger 210. The helium gun 108 (helium distributor) can be moved freely within the length of the piping 107 connected to the gun, allowing the gun's distribution nozzle 111 to be moved across the location of the unit under test 114 in which the helium leak test is performed.

[0014] Inside the main body 113 is an accelerometer 109 used to measure the motion or acceleration of the helium gun 108. Here, the accelerometer 109 can distinguish acceleration in the x, y, and z axes. The accelerometer 109 is connected to an accelerometer cable 115, which is wrapped around the piping 107, and also to a first CPU 142 line, which is connected at a distal position of the helium gun 108 and may include a pair of accelerometer bus wires isolated from each other and extending from the connection point with the accelerometer cable 115 to the CPU 110. The first CPU line 142 communicates information to the CPU 110 in the form of an electrical signal output from the accelerometer in response to the motion of the helium gun 108, indicating the speed of the helium gun 108's motion while helium is being dispensed from the gun. The first CPU line 142 is configured to communicate information regarding the acceleration of the helium gun 108 and therefore the speed of the gun. A second CPU line 144 connects the mass flow monitor 102 to the CPU 110, transmitting a signal from the mass flow monitor to the CPU 110 indicating the amount of helium flowing from the helium supply source 101 and therefore out of the nozzle 111 of the helium gun 108. The helium flow rate through the nozzle 111 of the helium gun 108 is monitored by the mass flow monitor 102, which outputs an electrical signal indicating the helium flow through it, and this electrical signal is electrically communicated to the CPU through the second CPU line 144. The CPU 110 is connected to a user interface 112. The user interface (UI) allows the user of the helium gun 108 to receive visual and auditory information regarding the operation of the system 100. During the test, while helium is being dispensed from the helium gun 108, if the acceleration or speed of the helium gun 108 reaches a preset maximum threshold, a signal is sent from the CPU 110 to the UI 112, which displays a failing test value and optionally sounds an audible alarm, displays a visual alarm, or both.

[0015] System 100 also includes test apparatus hardware and equipment, which includes a vacuum source 150 connected to a second fluid pipe 129 using fittings. The vacuum source 150 is a “house” source, used in multiple locations within the equipment, such as welded piping, or equipment using welded piping, or equipment that prepares both, and is accessible through a quick-connect coupler located adjacent to the table 103 where the helium leak test on the unit under test is performed. The second fluid pipe 129 houses a helium detector 128, for example, through a T-connect fitting to the vacuum pipe 129, screwed into the stem of the T-connect fitting, and the arms of the T-connect fitting are connected in a line within the second pipe 129, thereby fluidly communicating with the interior of the second pipe 129. Therefore, here, one arm of the T-connection fitting is fluidly connected to a house vacuum source 150, the second arm is fluidly connected to a reinforced hose 230 which leads to a coupler used to connect the vacuum source 150 to the unit under test 114, and the helium detector 128 is fluidly connected to a third arm or stem of the T-connection. If helium is drawn into the unit under test 114 through a hole in a weld or other part of the unit under test being evaluated as a result of the vacuum inside the unit under test 114, the presence of helium in the internal space of the unit under test 114 is detected by the helium detector 128 transferring the helium to the helium detector 128. The helium detector 128 transmits an electrical signal regarding the amount or concentration of helium detected to the CPU 110 through a helium detector line 127 composed of one or more conductors, which communicates an electrical signal corresponding to the helium detection by the helium detector 128 to the CPU 110. The helium detector 121 is powered by a power supply 130 and connected to the power supply 130 through a helium detector power cable 218.

[0016] The internal space of the second pipe 126 is fluidly connected to the internal space of the unit under test 114 through a reinforced hose 230, which can be selectively connected to the unit under test 114 at one end of the pipe via a coupler 124. The coupler 124 consists of a female fitting 120 and a male fitting 120. The opposite end of the unit under test 114 is sealed with a cap or other sealing device. The fitting is a cylindrical hollow metal fixture, and the female fitting includes a check valve with a spring that presses a ball against a sealing base, allowing the male fitting to be fitted into the female fitting and fastened to the female fitting with a leak-free seal, thereby reducing the pressure in the internal space of the unit under test 114 to a user-specified base (vacuum) pressure at which the unit under test 114 is evaluated for weld leakage. In addition, as described above, the helium detector 128 is in fluid communication with the internal space of the second pipe 129, and therefore, helium leaks through the welds of the unit under test 114 are communicated to the helium detector 128 through the reinforced hose 230 and the internal space of the second pipe 129. The female fitting 122 portion of the coupler 124 is welded to the end of the second pipe 129 or otherwise fluidically sealed, and the male fitting 120 portion of the coupler 124 is sealed to the unit under test 114. When the unit under test 114 is engaged with the male fitting 120, the open end of the piping of the unit under test 114 is locked into the cylindrical recess of the male fitting 120 with a leak-proof seal. When the male and female fittings 120 and 122 are fastened together, the fastening creates a continuous, leak-free, sealed line from the unit under test 114 to the vacuum source 150, and the helium detector 128 is in fluid communication with the inside of the second pipe 129 at a position between the unit under test 114 and the vacuum source 150.

[0017] In some aspects of the present invention, the vacuum source is a vacuum line in a house or facility to which the unit under test can be connected, but in an example of the present invention, the vacuum source 150 is a vacuum pump connected to a power supply 130 through a power line 215 that supplies power to operate the vacuum source 150. In other aspects, the vacuum source 150 can be the vacuum supply source in the aforementioned house or facility. When the vacuum source 150 is a separate vacuum pump, it is powered by the power supply 130. The vacuum source supplies gas or vapor, generally air, water vapor, or both, from the internal space of the unit under test 114 to reduce the pressure in the internal space of the unit under test 114 to the desired test pressure. When helium is released over the weld area of ​​the unit under test 114, if there is an opening larger than a helium atom in the weld joint and passing through the weld joint, the vacuum draws the helium released along the weld near the weld into the unit under test 114 through the weld. Helium is transferred through the reinforced hose 230 and the second pipe 129 to the location of the helium detector 128 to be detected, or is supplied by the vacuum source 150.

[0018] Inside the vacuum source 150, or within the second piping 129, is a pressure sensor 121 connected to the CPU via a vacuum sensor line 216. The pressure sensor 121 emits an electrical signal, which is transmitted along the vacuum sensor line 216 and indicates the fluid pressure within the second piping 129, and therefore within the internal space of the unit under test 114 connected to the piping. When the unit under test 114 is first connected to the second piping 129 via the coupler 124, the pressure within the second piping 129, which was pumped down to the base or test pressure and maintained by being sealed by a check valve in fitting 122, rises as the gas in the internal space of the unit under test 114 moves into the second piping 129. Next, the fluid (gas, water vapor, or both) in the combined volume of the internal space of the unit under test 114 and the internal space of the second piping 129 begins to descend. The pressure sensor 121 transmits electrical signals to the CPU 110 continuously or at a desired refresh rate, and the CPU 110 generates a pressure-based output to the UI 112, which displays a visual indication of the pressure in the internal space of the unit under test 114, which should be the same as or approximately the same as the pressure in the second pipe 129. The UI 112 can display the pressure as a number on its display monitor, and can also graphically illustrate the change in pressure in the unit under test 114 over time on the XY axis (X is time, Y is pressure), and may include a horizontal line on the graph that indicates the threshold pressure at which the pressure in the internal space of the unit under test 114 has decreased to reach the helium leak test pressure. The operator of the helium leak test on the unit under test 114 uses this threshold pressure line, and the pressure drop below that threshold pressure line, as indicators that the helium leak test on the unit under test 114 can be initiated.

[0019] The helium detector 128 is connected to the CPU 110 via a vacuum sensor line 216. The helium detector 128 is configured to output a signal indicating the detection of helium, and also the detection of the relative concentration or amount of helium in the second pipe 129 under test, which entered the fourth pipe 129 as a result of passing through the weld and entering the interior of the unit under test 114 due to the detection of helium. The concentration information can also be raw detector information showing the interaction between individual helium atoms and the detector, and the more atoms interacting with the helium detector 128, the larger the amplitude of the signal or the greater the number of individual signals representing the detection of individual helium atoms by the helium detector 128. The output from the helium detector 128 to the CPU 110 can be continuous or based on the sum of helium detections over discrete periods. This information transmitted to the CPU 110 is displayed on the UI 112 display as helium concentration information and is also plotted graphically on the XY axis (Y axis is concentration, X axis is time) along with pressure information. A preset threshold helium concentration is defined by the operator as the amount of helium that the helium detector 128 can detect during the test. Alternatively, the system 100 can be configured such that the CPU 110 receives identification information of the unit under test 114, including the type of the unit under test 114, such as a barcode attached to the unit under test 114 that can be read by a reader. The information may also include the threshold helium at which the unit under test fails the helium leak test, or the CPU 110 may internally include a lookup table that compares the identification information of the unit under test 114 with the helium threshold at which the unit under test 114 is considered to have failed the test. Additional information may include the time when the unit under test or individual welds of the unit under test were fabricated, the workstation or equipment used to fabricate the unit under test 114, and the one or more operators who assembled and welded the piping constituting the unit under test 114 together.Since helium is an inert and the smallest atom, other gases that can pass through the unit when the test unit 114 is installed in the equipment generally have much larger atomic or molecular sizes and cannot pass through an aperture through a weld joint that is the same as or slightly larger than the atomic diameter of helium. The CPU is configured to sound an alarm or display a warning of a failed test if the threshold allowable amount of helium detected by the helium detector 128 is exceeded. This failure notification can be visually displayed on the display of the UI 112 as a text-based failure signal, a red light display, or other markings. The UI 112 can also transmit the failure signal as an audible alarm. Additionally, if the coupler 124 does not form a properly sealed connection between the reinforced hose 230 and the test unit 114, or if one or more weld joints of the components connected into the test unit are not sufficiently airtight, the vacuum source 150 will be unable to reduce the pressure within the connected reinforced hose 230 and the test unit 114 to the test pressure, and the CPU can be configured to display or sound an alarm that there is an overall leak somewhere in the test unit 114, the coupler 124, and the second pipe 129. The CPU 110 can be configured to sound an alarm, display on the display of the UI 112, or both, if a specific amount of time has elapsed after the test unit 114 is connected to the reinforced hose 230 but the desired vacuum pressure has not been reached.

[0020] Figure 2 graphically illustrates some of this information. Figure 2 is a graph with the internal pressure of the unit under test 114 measured along the left Y-axis, the amount of helium detected along the right Y-axis, and time along the X-axis. Curve 136 represents the pressure inside the unit under test 114. Here, at t0, the unit under test is initially under atmospheric pressure and connected to the vacuum supply source 150 by connecting the fittings 120, 122 to each other, at which point the pressure inside the unit under test 114 begins to decrease as detected by the pressure sensor 121. Over time, curve 132 extends to a position below the test pressure, and at time t1, the operator distributes helium to the area of ​​the unit under test 114 in the weld. Curve 134 should be evaluated based on the left Y-axis, starting from when the trigger 210 of the helium gun is pressed down by the operator, and shows the amount or count of helium atoms detected over time. Here, the helium is slowly rising. The user establishes a test period for distributing helium. Here, the failing grades are plotted on the right-hand Y-axis. From t1 to t f Over the specified test period up to t1, the amount of accumulated helium detected is less than the failing level, and the unit under test 114 is considered to have passed. In contrast, the curve 136 of the detected helium for different units under test 114 is from t1 to t fIf the amount of accumulated helium detected over the specified period exceeds the failing level, this unit under test is rejected. The dashed curve 132a indicates that the unit under test cannot reach the vacuum required to begin the test, resulting in an overall leak somewhere in the test setup, the unit under test 114, or both connections. The operator then inspects all connections and retests the unit under test. If the vacuum test pressure cannot be reached, the unit under test 114 is excluded and a new unit under test 114 is connected. If this second unit under test reaches the test pressure, the first unit under test is rejected. If the second unit under test 114 cannot reach the test vacuum level, the operator must disassemble the vacuum components, inspect the vacuum pump to ensure it is functioning correctly, and reconstruct the test setup. The two units under test that failed to reach the vacuum test pressure are then retested.

[0021] One of the issues affecting the validity of helium leak test results is human error. One human error that can occur during testing is that the test operator delivers or releases helium gas from the helium gun 108 onto or adjacent to the portion of the unit under test 114 being evaluated for helium leaks before the internal pressure of the unit under test 114 reaches the desired test pressure, which is a vacuum pressure substantially lower than the ambient air pressure around where the test is being conducted. The likelihood that helium will enter an opening in the unit under test 114 that can pass helium, and the amount of helium gas that passes through the opening, depends on the helium availability at the opening through which it passes and the pressure difference between the internal space of the unit under test 114 and the outside. The amount of helium distributed by the helium gun is digital, as the helium gun is frequently calibrated by immersing the tip of the helium gun in liquid, determining the amount of gas released when the trigger 210 is pulled, and adjusting the helium pressure or the helium gun 108 to maintain a desired volumetric flow rate per unit time. Since the internal valve of the helium gun 108 moves between fully open and fully closed positions, it is not possible to adjust the helium flow between full flow and zero flow. Therefore, the main variable affecting the validity of the test is the amount of helium passing through the opening or gap, for example, in the weld 140, given the desired release of helium near the gap or opening. The test of the unit under test 114 is calibrated based on the helium flow rate from the helium gun and the pressure difference between the inside and outside of the unit under test 114. If the flow rate of the helium gun 108 is properly calibrated, starting the test before the internal space of the unit under test 114 reaches the desired level of internal vacuum pressure will result in fewer helium atoms passing through the opening or gap in the weld or piping of the unit under test 114, and as a result, units under test that should not be considered as passing units will be called passing units.The CPU 110 can be configured not to distribute helium until the pressure within the unit under test reaches the desired test pressure, or to provide the alarm signal described above in this specification if the vacuum pressure within the unit under test 114 has not reached the desired test pressure before the test is started by releasing helium from the helium gun 108.

[0022] To prevent helium from flowing before the desired vacuum pressure is reached within the unit under test 114, the CPU is optionally configured to send a control signal to the valve 123 in the helium supply line to open the valve only after the proper vacuum pressure is reached within the unit under test 114.

[0023] Another error induced by the operator during the helium leak test involves the operator moving the tip of the helium gun too fast and passing over the area of the unit under test 114 where the leak is being evaluated. Here, the CPU is configured to read the signal received from the accelerometer 109 of the helium gun to indicate that the helium gun has moved too fast, and the operator must repeat the test by pumping the internal space of the unit under test to the desired vacuum pressure and repeat the leak test. In this way, the system 100 increases the user's confidence in the significance and accuracy of the helium leak test and finds unwanted gaps in the leak paths of the welds or pipes being inspected.

[0024] A method for enabling repeatable helium leak testing of the unit under test is shown in Figure 3. In operation 1000, the SKU code of the unit under test 114, which uniquely identifies the unit under test, is scanned, including information such as part number, time completed, and other information desired by the operator. The information is read by the CPU 110, which is configured to associate the SKU number of the unit under test with a result test response indicating whether the unit under test 114 passes or fails. Next, in operation 1001, the unit under test 114 is securely fastened to the male fitting 120 of the coupler 124, and the male fitting 120 is inserted into the female fitting 122 of the coupler 124. This creates a leak-free seal between the internal space of the unit under test 114 and the second piping 129 having a vacuum source 150. In one embodiment, the vacuum source 150 may be started in operation 1003. In other embodiments, the vacuum source 150 remains on to maintain a pressure lower than atmospheric pressure within the reinforced hose 230. Once the vacuum 150 is turned on and pressure is applied to the unit under test 114, the UI 112 displays the pressure inside the unit under test 114. In operation 1005, the operator monitors the change in vacuum pressure inside the unit under test 114. The desired system pressure for the test to be performed on the unit under test is determined by the operator based on the pressure of the internal space of the unit under test 114 displayed on the user interface 112, or the CPU may be programmed with this set test pressure and display or emit information that the operator can use to visually, graphically, or audibly determine whether the test pressure has been reached. This test pressure is the set pressure at which the unit under test 114 will respond most appropriately to any possible minute leaks in the unit under test 114 or to the application of helium adjacent to a leak, and at which the entire system maintains the set vacuum pressure without further intervention.In operation 1007, the operator can ensure that the unit under test 114 reaches the desired test pressure by visually observing the pressure reading on the UI 112, or by allowing the CPU to monitor the pressure and generate an alert through the UI 112 when the unit under test 114 reaches the test pressure. Once the pressure reaches the desired test pressure, the operator can, in operation 1010, begin helium delivery using the helium gun 108. The operator distributes helium through the nozzle 111 of the helium gun by pulling a trigger 210 located outside the body 113 of the helium gun 108. The trigger 210 opens a valve inside the helium gun, allowing helium to exit the nozzle 111 at a desired, pre-calibrated constant flow rate. The flow rate is determined by the output of a mass flow monitor 102 (MFM) fluid-connected to the helium source 101. The MFM signal is used by the CPU 110 to determine that helium should only be released after the unit under test 114 has reached the test pressure. If helium is released when the pressure exceeds the test pressure, the CPU 110 sends a fail signal to the UI 112. This signals the operator to repeat the test while waiting for the appropriate test pressure to be reached. Alternatively, the CPU 110 controls the fluid switch on the helium line so that helium cannot flow from the helium source until the unit under test 114 has reached the test pressure. If the operator attempts to perform the test when the CPU 110 has not received a pressure signal from the pressure sensor 121 that adequately meets the pressure set to be the test pressure, the CPU displays a fail signal. In operation 1013, the CPU 110 uses the MFM signal to ensure that the helium delivery flow rate is within the appropriate range.

[0025] When the helium flow rate is within the appropriate range, the operator positions the helium gun 108 at the point of interest on the unit under test 114. Specifically, in action 1016, the operator positions the helium gun 10 such that the nozzle 111 is adjacent to the weld 140 of the unit under test 114 in order to test for leaks in the weld. In action 1019, the operator applies helium to these points of interest, such as the weld on the unit under test 114, by pulling the trigger 210 to release helium gas from the nozzle 111 of the helium gun 108. If there is a leak in the unit under test 114, the helium flows through the physical opening causing the leak, is drawn into the unit under test 114, and flows either by drawing vacuum pressure or by dispersing toward the helium detector 128. When helium atoms reach the helium detector, a reaction occurs so that the helium detector can identify the helium atoms and transmit a signal regarding the concentration of detected helium atoms to the CPU 110 via the vacuum sensor line 216. The helium concentration inside the unit under test 114 is displayed in the UI 112 during operation 1022. The helium threshold amount at which a weld test fails is set by the operator or stored in the CPU's lookup table and used to set the helium detection threshold at which a weld or unit under test 114 fails. If the helium detector detects helium exceeding the threshold amount, the UI displays a fail warning. The CPU 110 adds the helium concentration data, fail warning data, and SKU number data representing the actual unit under test 114 that failed to complete the test to a database accessible to the operator or other personnel. This database allows the operator or other personnel to use the SKU number to determine if there is a manufacturing defect and where this defect originated, and to identify the equipment and materials used to create the unit under test, the time when various welds were made on the unit under test, and the technicians who made those welds and built the unit under test 114. This allows operators or other personnel to make manufacturing decisions before expanding resources to produce more leaky test units 114.In addition, this same data, collected for passing units under test and using the amount of helium detected and the unit-to-unit variation in helium levels, can be used to enable preventive maintenance, identify problematic raw material lots, including performance trends over time, and identify issues with equipment, raw materials, and individuals involved in the manufacture of the units under test, in order to train or retrain technicians who manufacture the units under test. The data can also be used to reduce manufacturing process variability by identifying who, where, what, and when in the manufacturing process of the units under test and tracking the resulting variations in test performance.

[0026] In addition, if the accelerometer 109 inside the helium gun 108 detects that the operator is moving the helium gun 108 too quickly, the UI 112 displays a failure warning, and this accelerometer data and failure data are added to a database accessible to the operator or other personnel. Upon receiving a failure warning, action 1025 prompts the operator to repeat the test, this time moving the gun more slowly. This allows for an appropriate residence time of the nozzle of the helium gun 108 at the leak site, allowing helium to penetrate the unit under test if there is a leak. Based on the operator's failure rate due to accelerometer-based test failures, it can be determined whether further training is required for the test operator.

[0027] Figures 4-6 show the UI 112 screens viewed by the helium gun operator during a leak test. The UI screen 112 displays the SKU barcode of the unit under test 114 scanned for the leak test. The UI 112 displays a series of graphical information about the unit under test 114. The first flow graph displays the upper limit 909 and lower limit 901 of the leak reading, along with the actual leak reading 905. The threshold limits are defined by the operator and are based on the vacuum pressure in the unit under test and the flow rate of helium delivered from the gun. The second graph compares the helium concentration 912 in the unit under test with the helium being delivered from the helium gun. On the operator panel, the UI displays interactive manual start and stop for the leak test based on the vacuum pressure in the unit under test. The UI displays information about the test status and speed. The UI also displays the automatic start and automatic stop interfaces. The vacuum pump time during active testing is displayed. The UI displays the lead rate and indicates the test status as ongoing or failed, depending on the situation. Figure 3 shows a test during active testing. Figure 4 shows a leak test that failed due to leakage in the unit under test. This is indicated by the test result information that read the failure signal, as well as the leak flow rate which is graphically displayed as exceeding the leak limit. Information regarding the helium gun speed is written as slow, indicating that the gun movement was not too fast for a valid test. Figure 4 shows a leak test that failed because the helium gun movement was too fast during the test. This is indicated by the leak flow rate of 905 which is within the upper limit of 909 and the lower limit of 901, but the speed reading is fast.

[0028] Figure 7 shows an alternative structure for the accelerometer layout of the test system. Here, a first accelerometer 152 and a second accelerometer 154 are provided, each independently connectable to a first CPU line 142 via first and second accelerometer leads 156 and 158 configured to transmit signals output by the first and second accelerometers 152 and 154. The first accelerometer 152 is configured to be particularly sensitive to the movement of the output nozzle 111 in the centerline direction L, and the second accelerometer 154 is configured to be particularly sensitive to the movement of the output nozzle 111 in the rotational direction θ about the centerline direction. Using two accelerometers and mounting the two accelerometers on the nozzle 111 near the gas output position increases the accuracy of velocity detection in the helium gas discharge portion of the helium gun 108. However, a single accelerometer located above or inside the nozzle 111 is also specifically conceived herein.

Claims

1. A helium distributor that can be connected to a helium gas source to which a motion detector is connected, and is configured to selectively distribute helium, A vacuum source that can be releasably connected to the unit under test through a fitting, A helium detector fluidly coupled to the vacuum source, A controller is operably coupled to the helium detector and the motion detector and configured to receive an electrical signal indicating the speed of movement of the helium distributor when helium is distributed from the helium distributor. A device for detecting leaks in a unit under test, equipped with the necessary components.

2. The apparatus according to claim 1, wherein the controller is further configured to receive a signal from the helium detector indicating the amount of helium detected by the helium detector.

3. The apparatus according to claim 1, further comprising a pressure sensor that is in fluid communication with the inside of the unit under test, is connected to the controller, and is configured to transmit a signal indicating the pressure inside the unit under test to the controller.

4. The apparatus according to claim 1, further comprising a depressable trigger that, when pressed down, allows helium to flow from the helium distributor.

5. The apparatus according to claim 1, wherein the motion detector is at least one accelerometer.

6. A first joint of a pipe having a helium detector that is in fluid communication with an internal space, the apparatus according to claim 1.

7. The motion detector comprises a first accelerometer and a second accelerometer, The helium distributor includes a nozzle having an opening for distributing the helium, The first and second accelerometers, or the nozzles, are arranged in The apparatus according to claim 1.

8. The apparatus according to claim 7, wherein the nozzle has a central axis direction and the first accelerometer is configured to detect movement along the central axis direction.

9. The apparatus according to claim 7, wherein the nozzle has a central axis direction, and the first accelerometer is configured to detect circumferential motion about the central axis direction.

10. Scanning the SKU of the unit under test that provides SKU information, Transmitting the aforementioned SKU information to a computer, Connecting the unit under test to the test apparatus, To remove the gas from the internal space of the unit under test, Monitoring the vacuum pressure within the internal space of the unit under test until the vacuum pressure reaches the test pressure, By pulling the trigger of the helium gun and dispensing helium from the helium gun, the delivery of helium to the outside of the unit under test through the helium gun is initiated, Positioning the helium gun so that helium is released onto the welded portion of the unit under test, Detecting the movement speed of the helium supply gun while distributing helium, The helium content inside the unit under test is displayed on a graphical user interface. A method for detecting leakage in a unit under test, including [specific details omitted].

11. Furthermore, the method according to claim 10, wherein an accelerometer inside the helium gun transmits a signal to a computer monitoring the leak test.

12. The method according to claim 11, further comprising designating the unit under test as having failed the aforementioned leak test, and notifying the failure warning through a visual alert, an audible alert, or a warning on a user interface including a visual alert and an audible alert.

13. The method of claim 6, further comprising designating the unit under test as having failed the leak test and notifying the user of a failure warning through a warning on the user interface, wherein the method is performed as a result of the helium supply gun moving at a speed faster than a predetermined speed.

14. The method according to claim 9, further comprising establishing an acceptable range of helium to be detected within the unit under test with respect to the unit under test.

15. The method of claim 14, further comprising rejecting the unit under test and notifying the user of a failure warning through a warning on the user interface, including a visual alert, an audible alert, and a graphic display, of the amount of helium in the unit under test that is outside the acceptable range of helium.

16. The method according to claim 15, further comprising transmitting SKU information and rejection warnings to a database.

17. The method according to claim 16, further comprising analyzing the database to determine a point of failure in the manufacturing process.

Images