Sealed electrical device and method of making same

Abstract

A method of making a hermetically sealed electrical device includes providing an opening to an interior volume of the device. The method also includes backfilling the interior volume with a backfill gas via the opening. Once backfilled, the method includes disposing a ball or other plug into the opening to seal the opening. Additional sealing operations may also be performed at an interface of the opening and the plug.

Description

SEALED ELECTRICAL DEVICE AND METHOD OF MAKING SAMECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of International Patent Application No. PCT / US2023 / 075108, filed on September 26, 2023, and titled “Sealed Electrical Device and Method of Making Same,” the entirety of which is hereby incorporated by reference.FIELD OF THE TECHNOLOGY

[0002] The subject disclosure relates to electrical switching devices, such as contactor devices and electrical fuse devices, and more particularly to contactor devices with improved manufacturability and associated manufacturing methods.BACKGROUND OF TECHNOLOGY

[0003] Many conventional devices are known to selectively power on or off electrical devices. For example, electrical contactors, e.g., high-voltage DC contactors, and fuses, e.g., electrical fuses and / or pyrotechnic fuses are conventionally available and used in electrical systems. Contactors may be configured to interrupt or complete a circuit to control electrical power to and from a device. Fuses may be used for overcurrent protection. For example, fuses may be used to prevent short circuits, overloading, and / or permanent damage to an electrical system or a connected electrical device.

[0004] Many contactors and fuses, including those used in high-voltage, direct-current applications make use of an electrically-insulative, hermetically-sealed assembly that allows the internal atmosphere of the device to be controlled. Some conventional contactors and fuses include1SUBSTITUTE SHEET (RULE 26)hermetic seals formed using ceramic-to-metal or epoxy sealing. However, these conventional sealing technologies are expensive, resulting in expensive contactors and fuses. Moreover, epoxy sealing may have performance shortcomings, e.g., associated with cracking, poor sealing, and / or other issues that can cause inferior thermal and / or electrical performance.

[0005] Accordingly, there is a need in the art for improved hermetically-sealed contactors and fuses and methods of making such contactors and fuses.SUMMARY OF THE TECHNOLOGY

[0006] The subject technology relates to improved electrical devices and methods of making and using those devices. In examples, aspects of this disclosure relate to improved sealed, e.g., hermetically sealed, electrical devices and methods of making such sealed electrical devices.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] So that those having ordinary skill in the art to which the disclosed systems and techniques pertain will more readily understand how to make and use the same, reference may be had to the following drawings.

[0008] FIG. 1 includes textual and visual flowcharts showing an example process for making a sealed electric device, in accordance with aspects of this disclosure.

[0009] FIG. 2 is a cross-sectional view of a portion of an example electrical device made using the example process of FIG. 1, in accordance with aspects of this disclosure.

[0010] FIGS. 3, 4, and 5are cross-sectional views corresponding to the cross-sectional view of FIG. 2, in accordance with additional aspects of this disclosure.2SUBSTITUTE SHEET (RULE 26)

[0011] FIG. 6 is a flowchart demonstrating another process of making a sealed electrical device, in accordance with aspects of this disclosure.

[0012] FIG. 7 includes textual and visual flowcharts showing an alternative example process of making a sealed electrical device, in accordance with aspects of this disclosure.DETAILED DESCRIPTION

[0013] The subject technology overcomes many of the prior art problems associated with hermetically-sealed electronic devices and conventional methods of fabricating and assembling such devices. In brief summary, the subject technology provides improved hermetically-sealed electronic devices that are sealed using a press-fit component. Without limitation, the devices and techniques described herein may provide hermetically-sealed devices that are cheaper to manufacture than similar conventional devices. Moreover, the devices and techniques described herein may provide superior thermal and electrical performance relative to similar conventional devices.

[0014] The devices and techniques described herein may also provide hermetically-sealed contactors and fuses that use lower-cost manufacturing methods. Many conventional electrical devices are formed using a small diameter copper tube, known as a tubulation, to transport a gas, e g., a backfill gas, into an interior volume of the device. The gas is desirable to improve the performance of the device, but the tubulations and / or the processes for bonding them to the electrical device may be costly and / or complex. For example, the tubulations may be difficult to integrate into an automated manufacturing line. For example, in conventional manufacturing processes, after a gas is introduced through the tubulation to the interior volume of the device, the3SUBSTITUTE SHEET (RULE 26)tubulation is pinched off, creating a cold weld to seal the tubulation. Once sealed, the tubulations may not be robust to mechanical forces and / or may be prone to leaks.

[0015] Aspects of this disclosure may obviate the need for conventional tubulations. For example, according to some implementations, an opening or hole may be provided that facilitates fluid communication through a wall or surface of an electrical device. For example, the opening can be a hole formed through a weld plate, a cover, or other component and in fluid communication with the volume to be backfilled and / or hermetically sealed.

[0016] In some aspects of this disclosure, a gas, such as a backfill gas, is forced into the interior volume of the electrical device via the opening. For example, the gas may be supplied from a compressed gas source, which may be hydrogen, helium, nitrogen, and / or some other gas or gas mixture. In examples, the interior volume may be evacuated prior to backfilling.

[0017] After the interior volume is backfilled, in some examples a plug is press fit into the opening, to effectively seal the opening. In examples, the plug may be a spherical plug or ball that is pressed into the opening. In examples, the interference fit between the ball and the opening creates a gas-tight seal to retain the backfill gas after filling. In some examples, the plug may be a metal ball having a diameter equal to or greater than a diameter of the opening through which the gas is introduced into the interior volume of the electrical device. In other examples, the plug may be a cylindrical post, a flanged plug, and / or differently configured. In examples, the plug may provide a gas-tight seal for the life of the electrical device.

[0018] In some aspects of this disclosure, additional operations may be used to ensure the gas-tight seal throughout the life of the electrical device. For example, an additional filler may be added proximate the interface of the opening and the plug. Without limitation, an4SUBSTITUTE SHEET (RULE 26)epoxy, resin, adhesive, potting compound, and / or the like may be applied at the opening / plug to further seal the interface. In other implementations, the plug and / or the opening may be subjected to one or more of soldering, brazing, welding, or the like. However, the plug may provide a gastight seal until the subsequent operations are performed.

[0019] In some examples, the plug may not be press fit into the opening. Instead, the plug may be placed over or otherwise disposed proximate the opening. For example, a portion of the plug may be disposed in the opening, with some of the plug extending from the opening. When the plug is a ball, for example, the ball may have a larger diameter than the opening, such that the ball is not (or cannot practically be) press fit into the opening. In these examples, the plug may be otherwise secured relative to the opening, to seal the opening. For example, in some instances, the plug may be subjected to one or more of the additional operations discussed above. Without limitation, the plug may be soldered, brazed, welded, or epoxied in a position to seal the opening.

[0020] Aspects of this disclosure may reduce overall product cost by obviating the copper tubulation and bonding and crimping operations associated therewith. Moreover, because the press fit and / or placing of the plug into the opening is relatively easier than some other manufacturing processes, aspects of this disclosure may allow for relatively high-speed and / or relatively low cost manufacturing of a sealed electrical device. Even in instances in which the sealing is accomplished using additional operations, the device may be sealed via the plug. In conventional techniques, the machinery used to seal the tubulation may be required to be positioned in an atmosphere of the backfill gas. This may further complicate manufacture, as the backfill gas may be a highly-explosive mixture including hydrogen gas.5SUBSTITUTE SHEET (RULE 26)

[0021] While aspects of this disclosure may provide a number of improvements over conventional devices and processes, this disclosure is not limited to any of these improvements, and not all implementations of the systems and techniques described herein may result in these improvements. Moreover, while aspects of this disclosure may be particularly useful in electrical devices, such as contactors and fuses, the systems and techniques described herein may be useful with many hermetically-sealed applications.

[0022] Aspects of the disclosure will now be explained in more detail with reference to the Figures.

[0023] FIG. 1 includes textual and graphical flowcharts describing and illustrating a manufacturing process 100 for creating a hermetically sealed electrical device.

[0024] More specifically, as illustrated in FIG. 1, the manufacturing process 100 includes, at an operation 102, providing an access opening to an interior volume of an electrical device. An example 104 accompanying the operation 102 shows an example electrical device 106. The example electric device 106 includes a housing 108 at least in part defining an interior volume 110 (within the housing 108). The housing 108 and the interior volume 110 may contain a number of electrical and other components. For instance, the example 104 shows terminals or contacts 112 extending partially from a bottom (in the orientation of FIG. 1) of the housing 108. The contacts 112 may facilitate electrical coupling of the electrical device 106 to a power source (not shown) and a load (also not shown) as is conventionally known. The contacts 112 may extend partially into the interior volume 110, e.g., through holes formed in the housing 108 (not visible in FIG. 1). The housing 108 may be metallic, ceramic, polymeric, and / or formed of other materials.6SUBSTITUTE SHEET (RULE 26)

[0025] The electrical device 106 also is illustrated as including a can 114, e.g., formed as a cylindrical member extending above (in the orientation of FIG. 1) the housing 108, In examples, the electrical device 106 may be a contactor and the can 114 may house a plunger and / or other components for facilitating operation of the contactor. Without limitation, a plunger disposed in the can 114 may be secured to a movable contact, e.g., via a shaft or the like, that can be selectively moved into and out of contact with the contacts 112, e.g., to selectively facilitate and inhibit current flow the electrical device 106.

[0026] The electrical device 106 also is illustrated as including a plate 116, which may be a weld plate or the like. Without limitation, the plate 116 may cooperate with the housing 108 to define at least a portion of the interior volume 110. The plate 116 may also facilitate coupling of the can 114 and / or other features of the electrical device 106. In some examples, the plate 116 may be a metal plate, e.g., made from iron, steel, or other material. Although the housing 108, the can 114, and the plate 116 are reference and described separately, two or more of these components (and / or additional / different components) may generally form a housing assembly or housing structure for the electrical device. As will be appreciated, different electrical devices will have different housing components and structures.

[0027] An access opening 118 is formed in the plate 116. In examples, the interior volume 110 is bounded at least in part by the plate 116 and the access opening 118 extends through the plate 116, thereby providing a fluid passageway from outside the electrical device 106 into the interior volume 110. In some conventional electrical devices, a tubulation may be provided in the opening 118. However, aspects of this disclosure may obviate the need for such tubulations, and the manufacturing processes required to seal and otherwise manipulate the tubulations, as detailed further herein. Although the access opening 118 is formed in the plate 116 in the example of7SUBSTITUTE SHEET (RULE 26)FIG. 1, in other implementations the access opening 118 may be formed through other components of the housing assembly. Without limitation, the access opening 118 may be formed through the housing 108 or otherwise.

[0028] At an operation 120, the process 100 includes backfilling the interior volume of the electrical device with a backfill gas. An example 122 accompanying the operation 120 schematically illustrates the operation 120. Specifically, the example 122 shows the electrical device 106 and a gas supply 124. The gas supply 124 is configured to supply an amount of a backfill gas 126. The backfill gas 126 may be selected as a gas that improves arc suppression performance in the electrical device 106. Without limitation, the backfill gas may be an inert gas. In some examples, the backfill gas 126 may include one or more of hydrogen, nitrogen, or helium.

[0029] Although not illustrated in the example 122, tooling may be provided that forms a fluid passageway between the gas supply 124 and the opening 118 (and thus the interior volume 110). For instance, tooling can be brought into contact with the plate 116, e.g., about the opening 118, to form a seal circumscribing the opening 118. The backfill gas 126 may then be forced into the interior volume 110 from the gas supply 124. For instance, the example 122 includes an arrow 127 schematically illustrating the flow of the backfill gas 126 into the interior volume 110.

[0030] Also not illustrated in FIG. 1, in some instances the interior volume 110 may also be evacuated. For example, the interior volume 110, e.g., via the opening 118, may be subjected to a vacuum that removes residual or ambient air from the interior volume 110 prior to introduction of the backfill gas 126. In examples, the evacuation of the interior volume 110 may improve contactor performance by removing residual oxygen and / or moisture, which may be deleterious to components of the electrical device 106.8SUBSTITUTE SHEET (RULE 26)

[0031] At an operation 128, the process 100 includes press fitting a ball into the opening to create an interference fit between the electrical device and the ball to seal the opening. An example 130 accompanying the operation 128 illustrates the operation 128. Specifically, the example 130 shows a ball 132 that may be press fit into the opening 118. For example, the ball 132 may be a substantially spherical (e g., within standard tolerances) object having an outer diameter that is equal to or greater than a diameter of the opening 118. Thus, when the ball 132 is press fit into the opening 118, as schematically shown by the arrow 134 in the example 130, an interference fit results between the ball 132 and the opening 118. This interference fit creates a gas-tight seal between the plate 116 and the ball 132, resulting in a sealed volume 136. The size of the ball 132 relative to the opening 118 may be based at least in part on mechanical properties of the ball 132 and / or the plate 116. In at least some examples, the ball 132 may be formed of a metallic material, such as a malleable steel or the like.

[0032] In some examples, the operation 128 can be performed by machinery that feeds the ball 132 to a position proximate the opening 118 and / or presses the ball 132 into the opening. This processing may be much simpler than conventional tubulation associated processes described herein.

[0033] In some examples, the operation 120 and / or the operation 128 may be performed in an environment containing the backfill gas 126. For instance, the operation 120 and / or the operation 128 may be performed in a chamber that includes the backfill gas 126 (e.g., a hydrogen gas environment). In one example, to implement the operation 120, tooling in the chamber may seal against the plate 116, insert the backfill gas 126, and then retract from the plate 116. Second tooling may then insert and press the ball 132 into the opening 118. In other examples, the first tooling may be retained in place, e.g., sealed against the plate 116, while the ball 132 is pressed or9SUBSTITUTE SHEET (RULE 26)otherwise placed into the opening 118. The electrical device 106 is then sealed, and can be removed from the chamber containing the backfill gas. Any additional manufacturing operations, including additional sealing operations described below, may then be performed outside of the backfill gas 126 environment, which may reduce safety outcomes. That is, any subsequent welding, brazing, or the like, can be done at a different manufacturing station, e.g., outside of a hydrogen-rich environment.

[0034] The process 100 provides improvements over conventional tabulation techniques. For example, conventional techniques can include cold welding the tabulations in the backfill gas 126 environment. Because of the presence of the highly explosive gas, cold welding is used. However, cold welds are brittle and can lose their integrity if bumped after being pinched shut. Other conventional techniques may use resistance welding, but because of the presence of the backfill gas 126, tooling required is more complex and may require frequent dressing of resistance weld tooling. Instead, the techniques described herein provide a seal via a press-fit ball 132 may be accomplished with simpler tooling, at higher volume, and / or more safely. Moreover, the techniques described herein may eliminate the need for hydraulic pumps, hydraulic fluid, and / or hydraulic jaws that the tabulation method uses. Eliminating hydraulic fluid from a cleanroom may be a benefit to the manufacturing line.

[0035] FIG. 2 is a cross-sectional view 200 taken along the section line 2-2 in the example 130 accompanying the operation 128. As illustrated, ball 132 is pressed into the opening 118 extending through the plate 116 to form an interference fit between the ball 132 and the plate 116. The interference fit results in a gas-tight seal through which gas in the interior volume 110 cannot pass. In the example, the ball 132 is illustrated as being slightly deformed, e.g., being slightly pinched within the wall of the opening 118. As will be appreciated, the press fit may result in10SUBSTITUTE SHEET (RULE 26)deformation of the plate 116 (e.g., the wall of the opening 118) and / or the ball 132. The deformation will be largely dependent upon material properties of the plate 116 and the ball 132.

[0036] Although the example of FIGS. 1 and 2 contemplate press fitting of the ball 132 into the opening 118, e.g., as a plug that seals the opening 118, other shapes and / or configurations also are contemplated.

[0037] FIG. 3 shows an alternative arrangement 300 in which a plug 302 different from theball 132 is press fit into the opening. In the example of FIG. 3, the plug 302 may be a cylindrical plug, e.g., with a cylindrical sidewall configured to interfere with the opening 118. Although the plug 302 is illustrated as being substantially cylindrical, in other examples a sidewall of the plug 302 may be tapered. For instance, the plug may be frustoconical, instead of cylindrical. In still further examples, the sidewall may be arcuate, e.g., generally narrower at the top and / or bottom and wider at positions spaced from the top and bottom.

[0038] FIG. 4 shows another alternative arrangement 400 in which a plug 402 different from the ball 132 is press fit into the opening 118. In the example of FIG. 4, the plug 402 includes a body 404 sized to press-fit into the opening 118 and a shoulder or flange 406. The flange 406 has a diameter larger than a diameter of the opening 118, such that, upon press fitting of the plug 402 into the opening 118, the body 404 forms an interference fit with the plate 116, and the flange may contact a top surface 408 of the plate 116. In the example of FIG. 4, the body 404 is illustrated as being bulbous, e.g., partially approximating a spherical or similar arcuate shape, like the ball 132, along a portion to be inserted into the opening 118. In other examples, the body 404 may be otherwise shaped, e.g., including but not limited to cylindrical, frustoconical, or any other shape that can be press fit into the opening 118 to form the seal, as described herein.11SUBSTITUTE SHEET (RULE 26)

[0039] FIG. 5 shows another alternative arrangement 500 in which a plug 502 different from the ball 132 is press fit into the opening 118, In the example of FIG 5, the plug 502 is substantially hemispherical. In examples, the plug 502 may provide a similar or substantially the same interference fit as the ball 132, e.g., about the circumference of the plug 502. However, the hemispherical ball may provide additional benefits. For example, the plug 502 may be easier to handle than a spherical or ball-shaped plug. For instance, the plug 502 may lend itself more readily to bowl feeding or other conventional handling operations. Also in examples, the flat surface of the plug 502 may provide a surface by which to hold the plug 502 and / or align the plug 502 with the opening 118, e.g., during backfilling of the electrical device via the opening 118, as described herein. The flat surface of the plug 502 may also better cooperate with a flat surface on a pressing tool. For instance, the cooperation of these surfaces may inhibit rolling or other movement of the plug 502 relative to the pressing surface during pressing. The presence of the flat surface on the plug 502 may also provide a greater surface area (compared to the ball 132) for pressing by the pressing tool. The pressing tool may thereby experience less stress, which may lead to a longer tool life and / or reduced maintenance.

[0040] Although the example of FIG. 5 shows the plug 502 as hemispherical, other shapes including arcuate and / or spherical surfaces also are contemplated and may be used. For example, the flat surface may be formed other than through the center of a sphere. Of course, this may result in the flat surface being smaller than illustrated. In other examples, the plug 502 may be firusto- spherical, e.g., with two parallel flat surfaces separating an arcuate surface that approximates the shape of a sphere, instead of the single flat surface. As noted above, the plug 502 is for example, and other shapes and configurations including arcuate or spherical shapes may also be used. Also, combinations of shapes described herein also are contemplated. For example, and without12SUBSTITUTE SHEET (RULE 26)limitation, another example plug may be substantially cylindrical, as with the example of the plug 302, but may have a leading, hemispherical (bottom) end, like the plug 502. For example, the hemispherical leading surface may facilitate easier placement and / or insertion of the plug in the opening 118, but the cylindrical sidewall may provide greater sealing area with the opening 118 and / or may be easier to manipulate.

[0041] As noted above, the systems and techniques described herein can be incorporated into any type of electrical devices. So, for example, although FIG. 1 shows the opening 118 being formed in the plate 116, similar openings can be formed through other features of different devices. Without limitation, can-type electrical devices, e.g., having a cylindrical body and a cover or lid also are conventionally known. In these devices, an opening may be formed through the cover or lid, and the opening can be sealed with a ball or other plug press fit into the opening, as detailed herein. Any opening that can provide access to an interior volume to be hermetically sealed and into which a ball or other plug can be press fit may be used.

[0042] FIG. 6 is a flowchart illustrating a manufacturing process 600 similar to the manufacturing process 100 discussed above.

[0043] At an operation 602, the process 600 includes providing an access opening to an interior volume of an electrical device. For example, the operation 602 can generally correspond to the operation 102 of the process 100 discussed above. In examples, the access opening can be any opening that fluidly connects an interior volume to be backfilled with a gas and / or hermetically sealed with an environment outside the electrical device.

[0044] At an operation 604, the process 600 includes backfilling the interior volume of the electrical device with a backfill gas. For example, the operation 604 can generally correspond to13SUBSTITUTE SHEET (RULE 26)the operation 120 of the process 100 discussed above. In examples, the backfdl gas can be an inert gas and / or gas that facilitates arc suppression. The backfill gas can include one or more of hydrogen, nitrogen, and / or helium.

[0045] At an operation 606, the process 600 includes pressing a plug into the opening to create an interference fit between the electrical device and the plug, sealing the opening. In examples, the operation 606 may generally correspond to the operation 128 of the process 100 discussed above. Also in examples, the plug may be the ball 132, the plug 302, the plug 402, and / or any other plug that forms an interference fit with the opening to form a gas-tight seal at the opening.

[0046] The process 600 can also optionally include, at an operation 608, performing one or more additional sealing operations. As detailed herein, the press fit of the plug / ball may be sufficient to create a gas-tight seal. However, some implementations can also include one or more subsequent sealing operations, e.g., to improve or guarantee an integrity of the seal at the opening. Without limitation, the operation 608 can include applying an epoxy, resin, potting compound, adhesive, and / or other composition to the electrical device, e.g., proximate the interface between the ball and the opening. As noted above, these materials may provide additional seal integrity. In other instances, the operation 608 may include welding, brazing, soldering, and / or other processes to enforce the seal. As noted above, these processes may be difficult (and / or unsafe) to perform in certain environments, and because a seal already exists at the interference fit between the ball and the opening, this additional processing can be done in a different environment or at a different station entirely, e.g., spaced from an environment generally including the backfill gas. Separating processes into separate stations may be beneficial for high volume production. It may also lend itself to simpler tooling, which may be a general benefit for maintenance and repair costs.14SUBSTITUTE SHEET (RULE 26)

[0047] In some examples, the type of additional sealing operation performed at the operation 608 may depend on a type of the plug used. For instance, use of the ball may provide a space inside the opening, e.g., above the interfering surface, that may be particularly well suited to retain an adhesive, epoxy, a weld, or the like. Moreover, when a plug like the plug 402 that has the flange 406 is used, welding or soldering may be more readily used, because of the larger exposed surface area provided by the flange 406. Of course, these are for example only. Those having ordinary skill in the art with the benefit of this disclosure may implement the operation 608 differently. Moreover, although the operation 608 contemplates additional sealing operations as post-processes, it will be appreciated that because the electrical device is sealed at the operation 606, any (or no) post-process can be performed at this time. Unlike with conventional devices using tubulations, the electrical devices made according to the techniques described herein may be more robust and less likely to fail during additional processing.

[0048] FIG. 7 includes textual and graphical flowcharts describing and illustrating an alternative manufacturing process 700 for creating a hermetically sealed electrical device. Many aspects of the process 700 may be similar to or the same as the manufacturing process 100 described above. In FIG. 7, the same operations and components described above and illustrated in FIG. 1 are referenced with the same reference numerals. For example, the process 700 relates to a sealing operation for the electrical device 106 discussed above, and is illustrated as including the operation 120, which was detailed above with reference to FIG. 1. Moreover, the process 700 also includes the operation 102 discussed above.

[0049] As just noted, the process 700 includes the operation 120, which includes backfdling the interior volume of the electrical device with a backfdl gas. The example 122 accompanying the operation 120 schematically illustrates the operation 120. Specifically, the15SUBSTITUTE SHEET (RULE 26)example 122, detailed above, shows the electrical device 106 and the gas supply 124, which is configured to supply an amount of the backfill gas 126. The backfill gas 126 may be selected as a gas that improves arc suppression performance in the electrical device 106. Without limitation, the backfill gas may be an inert gas. In some examples, the backfill gas 126 may include one or more of hydrogen, nitrogen, or helium.

[0050] Although not illustrated in the example 122, tooling may be provided that forms a fluid passageway between the gas supply 124 and the opening 118 (and thus the interior volume 110). For instance, tooling can be brought into contact with the plate 116, e.g., about the opening 118, to form a seal circumscribing the opening 118. The backfill gas 126 may then be forced into the interior volume 110 from the gas supply 124. For instance, the example 122 includes an arrow 127 schematically illustrating the flow of the backfill gas 126 into the interior volume 110. In examples, the interior volume 110 may be evacuated prior to the backfill gas 126 being supplied to the interior volume 110.

[0051] At an operation 702, the process 700 includes disposing a ball at least partially in the opening. An example 704 accompanying the operation 702 illustrates the operation 702. Specifically, the example 704 shows a plug 706 (which may be similar to the ball 132 or any of the other plugs discussed above) that may be placed, disposed, or otherwise associated with the opening 118. For example, the plug 706 may be a substantially hemispherical (e.g., within standard tolerances) object having an outer diameter that is greater than a diameter of the opening 118. Unlike the ball 136, the diameter of plug 706 may be sufficiently larger than the diameter of the opening 118 that the plug 706 may not be able to be press fit into the opening 118. In other examples, the plug 706 may be capable of being press fit into the opening 118, but instead of being16SUBSTITUTE SHEET (RULE 26)press fit, at the operation 702, the plug 706 is instead placed in the opening 118, generally as shown in the example 704.

[0052] Thus, unlike the example of FIG. 1 in which the ball 132 is press fit into the opening 118, in the example 704, the plug 706 is placed in the opening 118. As a result, only a portion of the plug 706 is disposed in the opening 118, with the remainder of the plug 706 being disposed outside the opening, e.g., above the plate 116 in the orientation of the example 704. In at least some examples, the plug 706 may be formed of a metallic material, such as a malleable steel or the like. In some examples, the operation 702 can be performed by machinery that feeds the plug 706 to a position proximate the opening 118. This processing may be much simpler than conventional tubulation associated processes described herein.

[0053] At an operation 708, the process 700 also includes sealing the plug to the electrical device to seal the opening. For instance, because the plug 706 is not press fit into the opening 108, as in the process 100, the opening may not be sealed at completion of the operation 702. Instead, the process 700 includes the subsequent operation 708, which causes the plug 706 to seal the opening 118.

[0054] An example 710 accompanying the operation 708 shows a seal 712 created at an interface of the opening and the plug 706. More specifically, the example 710 illustrates that the seal 712 bonds the plug 706 to the plate 116. In this example, the plug 706 is fixed to the device 106 in a manner that retains a portion of the ball in the opening 118, thereby sealing the opening 118. The illustrated seal 712 may be formed via a number of methods. For example, the seal 712 can be formed by welding, brazing, soldering, and / or other processes. In still other examples, the seal 712 can be formed of an epoxy, resin, potting compound, adhesive, and / or other composition17SUBSTITUTE SHEET (RULE 26)applied to the electrical device, e.g., proximate the interface between the ball and the opening. In some examples, the operation 708 can correspond to the optional operation 608 from FIG. 6. Although the operation 608 was optional in FIG. 6, e.g., because the plug may be press fit into the opening in that example, FIG. 7 may require one or more additional operations to form the seal 712.

[0055] In some examples, the operations 120, 702, and / or 708 may be performed in an environment containing the backfill gas 126. For instance, one or more of the operation 120, the operation 702, and / or the operation 708 may be performed in a chamber that includes the backfill gas 126 (e.g., a hydrogen gas environment). In one example, to implement the operation 120, tooling in the chamber may seal against the plate 116 and insert the backfill gas 126. Second tooling may then insert the plug 706 into place proximate the opening 118 (with the first tooling still in place or removed). The operation 708 may then be carried out to create the seal 712 (with the first tooling still in place or removed). The electrical device 106 is then sealed, and can be removed from the chamber containing the backfill gas. In some examples, the operation 708 may be formed in a second chamber, e.g., that may not include the backfill gas. For example, it may not be desirable to perform certain operations, like certain welding operations, in a hydrogen or other inert gas-rich environment. In these examples, the plug 706 may be held in place (temporarily) while the electrical device 106 is moved from the first chamber to the second chamber, where the seal 712 is formed.

[0056] While the subject technology has been described with respect to preferred embodiments, those skilled in the art will readily appreciate that various changes and / or modifications can be made to the subject technology without departing from the spirit or scope of18SUBSTITUTE SHEET (RULE 26)the subject technology. For example, each claim may depend from any or all claims in a multiple dependent manner even though such has not been originally claimed.19SUBSTITUTE SHEET (RULE 26)

Claims

WHAT IS CLAIMED IS:

1. A method of manufacturing an electrical device, the method comprising: providing an electrical device having an opening providing access to an interior volume of the electrical device; backfilling the interior volume of the electrical device with a backfill gas via the opening; and disposing a plug in the opening to seal the backfill gas in the interior volume.

2. The method of claim 1, wherein the disposing the plug in the opening comprises pressing the plug into the opening, the plug forming an interference fit with the opening.

3. The method of claim 1 or claim 2, further comprising performing an additional sealing operation proximate the plug.

4. The method of claim 3, wherein the additional sealing operation comprises applying at least one of an epoxy, a resin, an adhesive, or a potting compound proximate an interface of the plug and the opening.

5. The method of claim 3, wherein the additional sealing operation comprises at least one of brazing, welding, or soldering.20SUBSTITUTE SHEET (RULE 26)6. The method of any one of claims 3-5, wherein the backfilling the interior volume and the disposing the plug in the opening are performed in a first controlled environment comprising the backfill gas and the additional sealing operation is performed in a second environment spaced from the first controlled environment and substantially free of the backfill gas.

7. The method of any one of claims 1-6, further comprising evacuating the interior volume of the electrical device via the opening, prior to backfilling the interior volume.

8. The method of any one of claims 1-7, wherein the plug is a ball.

9. The method of any one of claims 1-7 wherein the plug has a sidewall that is at least one of substantially cylindrical, arcuate, or frustoconical.

10. The method of any one of claims 1-9 wherein the plug comprises a flange for contacting a surface proximate the opening.

11. The method of any one of claims 1-10, wherein the opening is formed through a surface that at least partially defines the interior volume of the electrical device.

12. An electrical device comprising: a housing at least partially defining an interior volume;21SUBSTITUTE SHEET (RULE 26)an opening in a surface of the housing and providing a fluid passageway fluidly connecting the interior volume to an external environment of the electrical device; and a plug disposed in the opening and hermetically sealing a backfill gas in the interior volume.

13. The electrical device of claim 12, wherein the plug comprises a ball.

14. The electrical device of claim 12, wherein the plug comprises a sidewall that is at least one of arcuate, substantially cylindrical, or frustoconical, the sidewall providing the interference of the plug and the opening.

15. The electrical device of any one of claims 12 - 14, further comprising an additional seal proximate an interface of the plug and the opening, wherein the additional seal comprises at least one of an adhesive, an epoxy, a resin, or a weld.22SUBSTITUTE SHEET (RULE 26)

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