Patent Application
20070199593
Conduits are welded together in a wide variety of applications. Most commonly conduits are welded together in the assembly of flow systems. Such a welded connection can perform one of many functions, such as extending or terminating an existing flow path, redirecting flow in a flow path, reducing or increasing the size of the cross-sectional area of a flow path, splitting or combining flow paths, or inserting components, such as, for example, a valve, into a flow path. Conduits may include, for example, pipe, tubing, and various flow components such as, for example, valves and fittings with end connections adapted for welding.
During the welding of metal components, it is customary to attempt to lessen or eliminate the presence of oxygen at or near the surfaces being welded. This process is often referred to as purging. Limiting or eliminating oxygen at these surfaces during welding can limit or eliminate oxidation at the site of the weld. One method of lessening or eliminating the presence of oxygen or other contaminants is to pass inert gases across the surfaces to be joined during the welding process. By exposing the weld site to the inert gas and consequently purging out the oxygen-bearing atmospheric air normally present in the conduit to be welded, potential oxidation in the weld joint can be minimized. To effectively purge atmospheric air from a conduit to be welded, the open ends of the conduit may be sealed, thereby limiting flow through the conduit to smaller ports used to supply a purge gas and expel atmospheric air. One example of a device for sealing the ends of a conduit for controlling the flow of purge gas through the conduit is included in U.S. Pat. No. 4,723,064, incorporated herein by reference in its entirety, which describes a circular plate and gasket adapted to attach to a pipe end by toggle joints positioned inside the pipe end.
The present application relates in part to the assembly of a flow control device to an end of a conduit such that an internal surface of the conduit is not contacted by the device, through, for example, engagement of the device with an external surface of the conduit. The flow control device may include any device capable of limiting, regulating, directing, or blocking flow through the conduit. For example, the device may include a purge fitting which may be adapted to seal the end of the conduit and provide a smaller port or aperture through which purge gas may be introduced into (or evacuated from) the inside of the conduit.
The present application also relates to measuring a test pressure within a conduit, for example, before or during a welding operation to facilitate adjustment or maintenance of a desired pressure within the conduit. In one embodiment, a device assembled with the conduit may be provided with a test port at which the internal pressure of the conduit may be measured. In another embodiment, the test port may be located at or near an intended weld site prior to a welding operation, which may allow for adjustment of a purge gas flow through the conduit or conduits to adjust the pressure in the conduit or conduits.
The present application also relates to supplying a fluid, such as a purge gas, into an open end of a conduit assembly having an opposite blocked end, such that fluid flow reaches a desired region of the conduit assembly, such as an intended weld site, before exiting from the open end of the conduit assembly. In one embodiment, a flow control device assembled with the open end of a conduit assembly includes an inlet aperture for introduction of fluid flow into the conduit assembly, and an outlet aperture for exhaust of fluid flow from the conduit assembly. A purge channel extends into the conduit assembly from one of the inlet and outlet apertures and seals with the corresponding aperture, such that fluid flowing through the conduit assembly flows at least to an inserted end of the purge channel.
While the exemplary embodiments herein are described and illustrated for use with conduits to be purged for welding, the inventive aspects described herein may be applied to any conduit arrangement, for example, arrangements in which assembly of a conduit with a flow control device is desired without engagement of an internal surface of the conduit, or in which fluid is to be supplied or regulated through one or more conduits.
According to an inventive aspect of the present application, a device is provided for controlling the flow of fluid to a conduit. In one embodiment, the device includes an end portion that at least partially covers an end of the conduit, with an aperture in the end portion to receive the purge gas. At least one side portion extends from the end portion and directs at least one connecting member to engage an external surface of the conduit to secure the device against the end of the conduit.
According to another inventive aspect of the present application, an assembly is provided for controlling the flow of fluid through first and second conduits. In one embodiment, an inlet flow control device is assembled to a distal end of the first conduit, with an inlet aperture for directing fluid into the first conduit. An outlet flow control device is assembled to a distal end of a second conduit, with an outlet aperture for directing fluid out of the second conduit. A test device is assembled between proximal ends of the first and second conduits, with the test device having an aperture for providing communication between internal cavities of the first and second conduits, and a test port extending from an external surface of the test device and being in communication with the cavities of the first and second conduits.
These and other aspects and advantages of the present invention will be readily appreciated and understood from the following detailed description of the invention in view of the accompanying drawings.
The present application relates to assembling a flow control device to an open end of the conduit, for example, to limit flow through the conduit to an aperture to which a source of fluid is connected, or to maintain a controlled pressure inside the conduit. In one such application, the flow control device regulates the flow of purge gas though a conduit to be welded. The purge gas may, for example, include one or more of many inert gases commonly used to purge atmospheric air from a weld site, such as argon or helium. Similarly, an opposite open end of the conduit or conduits to be welded may, but need not, be sealed by a flow control device to block flow or to limit flow out of the conduit or conduits to a smaller aperture. In one example, flow of purge gas through the conduit may be directed to the internal surfaces of the conduit, for example, through the use of a gas diffuser or similar device. Additionally, flow of purge gases through the conduit may be regulated, through the use of a restrictor such as a regulating valve, to control pressure in the conduits. Further, an embodiment of the present application provides for attachment of the flow control device to the conduit end in such a way that the internal surface of the conduit is not engaged by the flow control device or by any mechanisms used to affix the flow control device to the conduit end. In some applications, it may be desirable to maintain a smooth surface finish and minimal contamination to the internal surface of the conduit, conditions which may be affected by engagement with a flow control device or related components. Another exemplary embodiment provides a flow control device which can be used with conduits of differing size or diameter. Further, another inventive aspect of the invention provides for a measurement of pressure inside the conduit or conduits at or near the weld site before welding, which may allow the purge gas flow and conduit pressure to be appropriately adjusted prior to welding.
In one embodiment, shown schematically in
The exemplary test device 130 and flow control devices 110, 120 may include one of any number of fluid system components, including, for example, fittings, valves, filters, and regulators. In the exemplary embodiment of
The inlet flow control device 110 of the exemplary embodiment of
A variety of gas diffusers may be used with the purge assembly. For example, a gas diffuser may include an obstructing member downstream of a flow source and positioned and adapted to direct a fluid flow outward, thereby diffusing the fluid over a larger area. One such example of an acceptable gas diffuser is illustrated in
While many different sealing arrangements may be provided between a flow control device and a conduit, in one embodiment, a seal member, such as, for example, an O-ring or a gasket, may provide a seal between the flow control device and an end face of the conduit. The inlet flow control device 110 of the exemplary embodiment may be provided with a gasket 113 or other such seal member positioned between the body 111 and the end of the conduit 10 to form a more effective seal between the flow control device 110 and the end face of the conduit 10. As the inlet flow control device 110 may remain assembled to the conduit 10 during a welding operation, the body 111 and gasket 113 are preferably constructed of materials that can withstand exposure to high temperatures. Additionally, the gasket 113 is preferably constructed of a closed-cell material, such as closed-cell silicone foam, that remains spongy, pliable and resilient during and after exposure to the elevated temperatures expected at the flow control device during the welding process.
The outlet flow control device 120 of the exemplary embodiment is provided with an outlet aperture 125 that passes through the outlet body 121. An outlet port 126 may be provided in communication with the outlet aperture 125 for connecting an exhaust line 40 to contain and direct purge gas and air expelled from the second conduit 20. The outlet port 126 may be provided with one of many types of suitable connections, such as threaded pipe ends, compression tube fittings, and quick-disconnect couplings, for example, and may be welded to or threaded into the outlet body 121, or any other suitable means of attaching the port. Additionally, a restrictor 50 may be connected to the outlet port 126 to regulate the flow of gases (both displaced air and purge gas) exiting the conduit 20, thereby regulating the pressure inside the conduits 10, 20. The restrictor 50 may, for example, include a regulating valve, such as a needle valve, which may be operated to increase or decrease the flow through the conduits 10, 20. It should be noted that a restrictor may additionally or alternatively be assembled to the inlet port 116 of the inlet flow control device 110, thereby regulating the flow of fluid into the conduits 10, 20.
The outlet flow control device 120 may also be provided with a gasket 123 or other suitable seal member positioned between the body 121 and the end face of the conduit 20 to form a more effective seal between the flow control device 120 and the conduit 20. As the outlet flow control device 120 may remain assembled to the conduit during a welding operation, the body 121 and gasket 123 are preferably constructed of materials that can withstand exposure to high temperatures. Additionally, the gasket 123 is preferably constructed of a closed-cell material, such as closed-cell silicone foam, that remains spongy, pliable and resilient during and after exposure to the elevated temperatures expected at the flow control device during the welding process.
The exemplary test device 130 is provided with a test aperture 135 that passes through the test device body 131. The test aperture 135 provides an opening between the internal cavity 15 of the first conduit 10 and the internal cavity 25 of the second conduit 20, so that the internal cavities 15, 25 are in communication with each other. Further, the exemplary test device 130 is provided with a test channel 138 that extends from an external surface of the test device 130 to a second surface of the test device body 131 in communication with the conduit cavities, such as the internal surface of the test aperture 135. The test channel 138 may be provided with a test port 139 for connecting to a pressure measurement device 60, which may provide a measurement of the internal pressure of the sealed conduits 10, 20. The test port 139 may be provided with one of many types of suitable connections, such as threaded pipe ends, compression tube fittings, and quick-disconnect couplings, for example, and may be welded to or threaded into the test device body 131, or any other suitable means of attaching the port. It should also be noted that a test port and test channel may alternatively or additionally be provided with the inlet flow control device and/or the outlet flow control device, such that the test channel extends from an external surface of the device to intersect the aperture, to provide for connecting to a pressure measurement device for measuring the internal pressure of the sealed conduits 10, 20.
The test device 130 may also be provided with gaskets 133 or other suitable seal members positioned between the body 131 and the end faces of the conduits 10, 20 to form a more effective seal between the test device 110 and the conduits 10, 20. Since the test device 130 is removed from between the conduits 10, 20 prior to welding, the thermal properties of the materials used to construct the test body 131 and gaskets 133 may not be important. As such, the test device 130 may be constructed of inexpensive and/or lightweight materials, such as plastic or aluminum. It may be preferable to construct the gaskets 133 in a material that is soft enough to create an adequate seal yet resistant to generation of particulate that would contaminate the conduits. An example of such a material is closed-cell silicone foam.
To adjust and test the internal conduit pressure of the exemplary conduit and purge assembly 100 of
One of any number of weld fixtures may be used to hold the conduits together in alignment for welding by a suitable weld process such as, for example, orbital welding. An example of such a welding fixture for use in an orbital welding operation is disclosed in pending U.S. Pat. Application Publication No. 2006/0016857, for HIGH PRODUCTION WELD FIXTURE, which is incorporated herein by reference in its entirety.
Since leakage of purge gas from between the conduits 10, 20 is likely to occur during the welding operation, after the test device 130 and gaskets 133 have been removed and the conduits are butted against each other, the purge assembly 100 is likely to produce a lower internal pressure in the conduits 10, 20 during welding than what was measured prior to welding with the test device 130 installed between the conduits 10, 20. Therefore, it may be desirable to perform testing of the internal conduit pressure during purge testing (with the test device installed) compared to the corresponding internal conduit pressure during welding (with the test device removed and conduits butted together), to determine an adjustment factor. For example, using a constant pressure at the fluid source 30 and a constant setting or operating position of the restrictor 50, a pressure measurement is first taken with gaskets 133 assembled between the test device 130 and the conduits 10, 20, and a pressure measurement is subsequently taken with the test device 130 and/or gaskets 133 removed. The two pressure measurements may then be compared to each other to determine an adjustment factor. By applying the adjustment factor to the pressure measured at the test port during purge testing (with the test device 130 and gaskets 133 installed), the equivalent internal pressure during welding may be estimated, and the pressure while assembled to the test device 130 may be adjusted accordingly, through adjustment of the restrictor 50.
It should be noted that while the test device 130 is installed, prior to a welding operation, the type of gas used to test the pressure may be unimportant. As such, other gases, such as, for example, nitrogen or air, may be used while testing the purge assembly 100, with these gases being replaced with a more conventional purge gas, such as argon or helium, once the purge test is complete and the conduits are prepared for welding. However, it should also be noted that differing leak rates for different gases may be a factor to consider when using the measured test pressure to determine an equivalent welding pressure.
By adjusting the restrictor 50 and monitoring the pressure measurement device 60, the assembly may be set to provide a nominal internal pressure for the sealed conduits 10, 20 prior to initiating a welding operation. It is often desirable to maintain a nominal positive pressure inside the conduits 10, 20 during welding to provide a clean, flush, and fully penetrated weld along the entire weld seam. As such, by maintaining a predetermined internal pressure in the conduits, the quality of the weld may be enhanced.
According to another inventive aspect of the present application, a flow control device, such as, for example, the exemplary purge fittings described herein and illustrated in
Any extension of the purge channel 346 into the conduit assembly 300 may assist in proving circulation of the introduced fluid within the conduit assembly, for example, by preventing fluid introduced through the inlet port 344 from immediately exiting through the outlet aperture 345. In one embodiment, to supply a fluid, such as, for example, a purge gas, to a desired region of the conduit assembly 300, such as, for example, the intended weld site (between the conduits 310, 320 upon removal of fitting 330 and abutment of the conduits 310, 320), a first end 346a of the purge channel 346 may be positioned to extend at least to the desired region, thereby forcing the introduced fluid to flow to the desired region before exiting through the purge channel 346. By providing an adjustable seal, such as a gasket 347, as opposed to a weld seal, the purge channel 346 may be adjusted to extend into the conduit assembly 300 by different lengths, to provide fluid flow at different locations in the conduit assembly, for example, to accommodate conduits 310 of varying lengths. A second end 346b of the purge channel 346, may, but need not, extend out of the conduit assembly 300, for example, to direct exhausted fluid into the environment or to connect with a container for reuse or safe retention of the fluid. While the purge channel 346 may alternatively be assembled with the inlet aperture 343 (not shown), the use of a diffuser 348 with the inlet aperture may limit use of the purge channel 346 to assembly with the outlet aperture 345. A restrictor 350, such as, for example, a regulating valve, may be assembled with the purge channel 346 to control the flow of fluid exiting the conduit assembly 300. Additionally or alternatively, a restrictor may be assembled with the inlet port 344 to control fluid flow through the conduit assembly.
Inlet and outlet flow control devices 110, 120 may take a wide variety of different forms. In one embodiment, the flow control device contacts or engages an outside surface of the conduit, but does not contact an inner surface of the conduit. In the example illustrated by
Further, while the flange 212 of
Test devices can take a wide variety of different forms. For example, the test device may contact or engage outside surfaces of the conduits, without contacting inner surfaces of the conduits. In one embodiment, a device 230, such as the test device 130 of
Further, while the flange 232 of
The embodiments of
While various inventive aspects, concepts and features of the inventions may be described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects, concepts and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present inventions. Still further, while various alternative embodiments as to the various aspects, concepts and features of the inventions—such as alternative materials, structures, configurations, methods, circuits, devices and components, software, hardware, control logic, alternatives as to form, fit and function, and so on—may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts or features into additional embodiments and uses within the scope of the present inventions even if such embodiments are not expressly disclosed herein. Additionally, even though some features, concepts or aspects of the inventions may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless expressly so stated. Still further, exemplary or representative values and ranges may be included to assist in understanding the present disclosure; however, such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated. Moreover, while various aspects, features and concepts may be expressly identified herein as being inventive or forming part of an invention, such identification is not intended to be exclusive, but rather there may be inventive aspects, concepts and features that are fully described herein without being expressly identified as such or as part of a specific invention, the inventions instead being set forth in the appended claims. Descriptions of exemplary methods or processes are not limited to inclusion of all steps as being required in all cases, nor is the order that the steps are presented to be construed as required or necessary unless expressly so stated.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/772,446, entitled “Devices and Methods for Purging Conduits” and filed Feb. 10, 2006, the entire disclosure of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60772446 | Feb 2006 | US |
