Patent Application
20220314374
Weld purging includes removing oxygen and water vapor from the vicinity of a welding joint. In the absence of weld purging, oxygen and hydrogen may combine with the hot metal to form undesirable compounds that may reduce corrosion resistance and otherwise weaken the welding joint. A common method to remove these gases from a weld is by flushing them away with an inert gas, such as argon.
When welding together sections of pipe, a clean weld is required inside and outside the pipe. Weld purging on the outside of the pipe is accomplished through a supply of inert gas through the welding wand, itself. Traditionally, purging the inside of the pipe has been effectuated by introducing inert gas into the pipe to push out the natural atmosphere. The amount of inert gas and the time required increases with increased pipe sizes. In some situations, this causes undesirable welder downtime and excessive inert gas consumption.
A system for welding pipe sections together includes first and second disks, each having a central portion and a resilient material outer portion. The central portion is more rigid than the outer portion. An outside dimension and shape of each outer portion is configured to engage an interior of a pipe having an inner dimension that is smaller than the outside dimension of the outer portion to establish a sealed interface between the outer portion and the interior of the first pipe section. The disks establish a chamber that overlaps a weld seam between abutting pipe sections. An inert gas introduced into the chamber effectively removes any air in the chamber so that a weld can be completed without any undesired gas near the weld seam.
The various features and advantages of at least one disclosed example embodiment will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
Embodiments of this invention facilitate welding pipe sections together by establishing a chamber within the pipe where inert gas can replace air that is otherwise present and would interfere with achieving a good quality weld.
The first disk 12 includes a resilient outer portion 18 and a central portion 22. The second disk 14 includes a resilient outer portion 20 and a central portion 24. The central portions 22, 24 are more rigid than the resilient outer portions. In the illustrated example, the central portions 22, 24 each include two plates or sheets 22a, 22b, 24a, 24b that sandwich at least some of the resilient material that establishes the corresponding outer portion 18, 20.
The disks 12, 14 are each capable of establishing a sealed barrier within a pipe. The resilient outer portions 18, 20 may be considered flexible seal portions that are configured to engage an interior surface on a pipe section to establish a sealed interface between the disk and the pipe. In some embodiments, the resilient outer portions 18, 20 comprise a durable, natural gum rubber that is ¼ inch thick. The more rigid central portions 22, 24 in the illustrated example comprise plates or sheets of high-density polyethylene plastic that is ¼ inch thick. Fasteners 28, such as screws or bolts, secure the plates of the central portions 22, 24 together on opposite sides of the resilient material.
Although the example disks 12 and 14 have a sandwich or layered construction, other embodiments are constructed differently. For example, the disks 12 and 14 can have a single-layer construction with a ring of the resilient material that establishes the outer portion 18, 20 secured around a periphery of a more rigid central portion.
The first disk 12 includes an inlet 30 that includes a resilient tube 32 protruding from one side of the central portion 22. An inlet passage 34 extends through the central portion 22 of the first disk 12. The resilient tube 32 is configured to be coupled with a source of an inert gas, such as argon.
A handle 36 is connected with the central portion 22 in an off-center position. The handle 36 is useful for manipulating the disk 12 relative to an inside of a pipe to position the disk in a desired location during installation or to remove the disk 12 from the pipe. The handle 36 includes at least one surface that can be grasped by a user for manipulating the disk 12. In some embodiments, the handle 36 is part of the rigid central portion. In the illustrated example, the handle 36 comprises additional hardware secured to the central portion 22. In the illustrated example embodiment, the handle 36 includes a spherical end. In other embodiments, the handle 36 comprises at least one eyebolt or similar hardware that facilitates manipulating the disk 12 into or out of a position within a pipe. The off-center position of the handle 36 makes it easier to remove the disk 12 from a pipe in which the flexible outer portion 18 engages an inner surface of a pipe.
The second disk 14 includes a similar handle 40 that is useful for manipulating the disk 14 relative to an interior of a pipe section. An elongated retrieval member 42 is secured to the central portion 24 in an off-center position. The elongated retrieval member in this embodiment comprises a cable, such as a steel or polymer strand cable. The second disk 14 also includes a centrally located opening or through passage 44.
The retrieval cable 42 extends through a passage 46 in the central portion 22 of the first disk 12 so that part of the cable 42 extends between the disks 12 and 14 and another portion extends beyond the first disk 12. In this example embodiment, a sleeve member 48 near at least one of the passage 46 is received about the cable 42. The sleeve may but need not establish a partially sealed interface around the cable 42.
At least one of the disks 12 and 14 in some embodiments include a cover plate or label, which is laid over the rigid central portions 22, 24. The cover plates may include size and branding information and serves to protect the central portions 22, 24. The cover plates 33 may be a thin gauge aluminum or stainless-steel plate.
An inert gas supply is connected to the sleeve 32 to introduce pressurized inert gas G into the isolated chamber 56. The inert gas G is preferably argon, but may be helium or nitrogen. Tape may be applied around the weld joint 54 where the ends of the pipe portions abut to better seal the chamber 56. The central hole 44 in the second disk is open and serves as a vent for air to exit the isolated chamber 56 as the chamber 56 becomes essentially filled with the inert gas G. Other openings may be included or used as a vent. For example, the hole 46 through which the retrieval cable 30 is received is some embodiments is not sealed and, therefore, allows for some venting of air from the isolated chamber 56.
The chamber 56 established by the system 10 reduces the volume of atmospheric air that needs to be removed from inside the pipe near the weld joint 54. Instead of having to essentially fill an entire length of the pipe sections prior to welding, only the chamber 56 needs to be filled with enough inert gas to minimize or eliminate undesired gas from the vicinity of the weld seam 54. For example, the first pipe section 50 may be added on to a significantly long second pipe section 52. Purging the entire interior of both pipes prior to welding wastes valuable welder time and inert gas. In contrast, the example system 10 allows a welder to much more quickly and economically purge atmospheric gas from the isolated chamber 56, which advantageously decreases the amount of time spent waiting for the inert gas supply to flush out atmospheric gas and the amount of inert gas needed.
Once a weld is completed, a user may remove the disks 12 and 14 from inside the welded pipe by pulling on the handle 36 to remove the first disk 12. Once the first disk 12 is out of the way, the second disk 14 may be removed by grabbing the handle 40 and manipulating the second disk 14 to remove it. If the distance to the weld seam 54 is too far into the pipe to reach the handle 40, the retrieval cable 42 can be pulled to remove the second disk 14.
In some situations, the cable 40 facilitates removing both of the disks 14 and 12 from the open end of the pipe. The retrieval cable 42 facilitates removing the disks 12, 14 when the location of the weld is deep enough within an open-ended pipe where neither handle 36 or 40 is accessible. The off-center location of the retrieval cable 42 facilitates tilting the first and second disks 12 and 14 relative to the interior of the pipe, which makes removing the disks easier
The resilient outer portions 18, 20 and the central portions 22, 24 may be dimensioned to work appropriately for various pipe diameters. The resilient outer portions 18, 20 have an outer dimension or diameter (Df) that is larger than the inner diameter Dp of the pipe in which the system 10 will be used. Accordingly, when the disks 12, 14 are placed within a pipe, the outer portions 18, 20 flex or bend (as shown in
A ratio of the outer diameter of the outer portions (Df) to the pipe inner diameter (Dp) is preferably between 1.0 and 1.5. In some example embodiments, the ratio Df to Dp is between 1.06 and 1.25. These ranges assist in achieving an appropriate seal along the interior of the pipes to be welded together while also facilitating inserting and removing the disks 12 and 14.
The plates 22a, 21b, 24a and 24b of the central portions 22, 24 include a diameter (Dc), which may also be varied to be appropriate for a specific pipe size. A ratio of Dc to pipe diameter Dp is preferably between 0.5 and 0.9. In some embodiments, the ratio of Dc to Dp is between 0.62 and 0.84. Additionally, a ratio of Dc to Df is preferably between 0.4 and 0.85. In some embodiments, the ratio of Dc to Df is between 0.5 and 0.78. The ratios of Dc/Dp and Dc/Df both assist in giving the disks 12, 14 sufficient rigidity to be manipulated into place where they remain until the chamber 56 is no longer needed (i.e., after the weld is complete) and contribute to forming an appropriate seal.
Nine exemplary configurations of the dimensions Df, Dc and Dp are provided in Table 1 below:
Although a particular component arrangement is disclosed and illustrated, other arrangements may become apparent to those skilled in the art who have the benefit of this disclosure. Placement and orientation of the various components of the illustrated embodiments could vary from the illustrated example. In addition, the drawings accompanying this disclosure are not necessarily drawn to scale, and some features may be exaggerated or minimized to emphasize certain details of a particular component.
The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.
This application claims priority to U.S. Provisional Application No. 63/170,019 which was filed on Apr. 2, 2021.
| Number | Date | Country | |
|---|---|---|---|
| 63170019 | Apr 2021 | US |
