Clamping system and method for use with steam dryers

Abstract

The clamping system includes a number of separate clamps that can be joined to components that are subject to relative rotation. The clamps may have similarly positioned features to simplify installation and / or removal in a small area of ​​all the clamps in the system. Each clamp is not free to rotate relative to an adjacent clamp, but does not pass vertical loads to the adjacent clamp. The clamps may use mating features such as extensions and recesses to limit rotation. The clamps are individually secured by fitting around and applying a biasing force against the component. At least one clamp has a transition surface that provides space between the clamp and the component to provide containment for the weld or other joint structure. The clamping system may be tightened with an attached fastener. A crimp nut or other locking structure may maintain the biasing and securing properties of the clamp and its underlying structure. The clamping system may be used to secure or repair lift rod assemblies.

Description

Related Applications

[0001] This application claims priority under 35 U.S.C. § 119 to co-pending U.S. Provisional Application No. 63 / 297,136, filed January 6, 2022, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] Figure 1 illustrates a prior art steam dryer 10 that may be used in a nuclear reactor, such as a steam dryer for a boiling water reactor, located above the reactor core and steam separator 5. As shown in Figure 1, the dryer 10 may include a hood 11 that shrouds the superheated steam and directs the superheated steam through baffles or vanes 12 to remove residual two-phase flow from the steam. A skirt 13 may position the dryer 11 in the upper reactor section at the top and surround the steam separator 5 at the bottom.

[0003] During construction, decommissioning, or maintenance outages, the dryer 10 is not fixed and may be moved relative to the reactor, such as from the reactor to a staging area within the containment vessel. Such manipulation or movement may use overhead trolleys, cranes, and / or cables secured to one or more lift rod assemblies 20 of the dryer 10. The lift rod assemblies 20 may be located in any number on the edge or within the dryer 10 to allow for reliable movement of the dryer 10. The lift rods 26 of the lift rod assemblies 20 may extend the full vertical length of the vanes 12, past the hood 11 to the base, with one or more ligaments 15 or other connectors ensuring fully fixed movement for the lift rods 26.

[0004] FIG. 2 is a detailed view of the end of the lift rod assembly 20, showing the connections between the lift eye 21, the lift lug 22, and the lift rod 26. As shown in FIG. 2, the lift eye 21 and its lower lift lug 22 may extend above the top of the hood 11 for clearance purposes. The lift eye 21 and lift lug 22 are attached to the lift rod 26 via a screw 25 or other connection in a central hole in the lift lug 22 that receives the reverse threaded end of the lift rod 26, allowing for a more firmly joined assembly of the lift rod 26 with the hood 11 and / or ligaments 15. Finally, the lift lug 22 and lift rod 26 may be more permanently secured, such as by a tack weld 23 on the shoulder of the lift lug 22 and lift rod 26, or other connection that prevents movement, including rotation, of the lift lug 22 relative to the lift rod 26.

[0005] This Background provides a useful baseline or starting point for better understanding some exemplary embodiments described below. Except for any expressly identified third party subject matter that may have been submitted separately, this Background and the drawings have been prepared by the inventors for the purposes of this application. None of the content of this application is necessarily known or represented as prior art. Summary of the Invention [Means for solving the problem]

[0006] An exemplary embodiment includes a clamping system for repairing rotatable components, such as lift lugs and lift rods of a steam dryer lift rod assembly. Multiple clamps that can be tightened and loosened independently can clamp different components and move with them. The clamps can prevent rotation between the components by limiting rotation between the clamps, in some cases, for example, blocking each other after a limited rotation of about 2 degrees. The clamps may otherwise be separately movable and not transmit translational forces between the clamps. For example, the clamps may use corresponding shapes, such as tabs and recesses separated by a gap, to achieve rotation-only limitation. The clamps may vary in shape and size, as they can be individually adapted to the shape of the underlying component to be secured. For example, the clamps may be substantially circular clamshell clamps with different diameters. In this way, for example, when a lift rod is threaded and welded into a hole in a lift lug, at least one clamp limits flow vibrations and debris dispersion by accommodating the hole and / or weld between the matching inner surface and the lift rod. The clamping system in the exemplary embodiment may not require the use of separate pieces to fasten the pieces to the underlying components. For example, a swing bolt may be used that is captured within the clamp and is movable only between a clamped position and an open position relative to the clamp. Associated nuts, washers, and any other fastening elements may be similarly captured. A crimp nut, ratchet surface, or other lock may be used to lock the clamp at a desired tightness without additional components. Each clamp in the exemplary embodiment system may have symmetrical fastening components, such as bolts and hinges, in the same relative positions to simplify installation and / or removal in a small area of ​​all the clamps.

[0007] In an exemplary method, the clamping system in the exemplary embodiment may be used to repair a lift rod assembly of a steam dryer. In an exemplary method, different clamps may be drawn around the lift lugs and lift rod on either side of where the two cross each other to form the lift rod. Once secured, the clamps may be separate, but may be located close enough to stop the clamps themselves, the lift lugs and the lift rod from rotating. For example, a tab and recess may be inserted during installation to allow up to 2 degrees of relative rotation and then stop the rotation. The clamp may be tightened by rotating a hinged bolt into the recess of the clamp and tightening a nut on the bolt to draw the clamp pieces together. Additional pieces to tighten the bolt may not be needed because all the clamp pieces, bolts, nuts, washers, etc., can be joined as a single component that cannot be lost and simplifies installation. The bolt can be locked in place to secure the clamp to the lift lugs and lift rod. Additionally, the dryer may be mounted or otherwise handled in any manner by the lift rods, thereby reducing the possibility of failure and creating debris in or around the reactor when applying the clamping system in the exemplary embodiments. [Brief description of the drawings]

[0008] Exemplary embodiments will become more apparent from a detailed description of the accompanying drawings, in which like elements are designated by like reference numerals. The drawings are for illustrative purposes only and are not intended to limit the exemplary embodiments herein. Elements in these drawings may be drawn in proportion to one another to accurately represent the shape, position, operation, and / or wording of the exemplary embodiments, and some or all elements may be drawn in proportion or modified to show different proportions and details.

[0009] [Figure 1] FIG. 1 is a diagram of a prior art nuclear reactor steam dryer. [Diagram 2]FIG. 2 is a detailed view of a lift rod assembly of the steam dryer of FIG. 1. [Diagram 3] FIG. 1 is a perspective view of a clamping system in an exemplary embodiment. [Figure 4] FIG. 4 is a front view of the clamping system in the exemplary embodiment of FIG. 3. [Diagram 5] FIG. 4 is a top view of the clamping system in the exemplary embodiment of FIG. 3. [Figure 6] FIG. 2 illustrates an exemplary embodiment of a clamping system mounted to a lift rod assembly of a steam dryer. [Figure 7A] FIG. 7 is a cross-sectional view of the front of the clamping system in the exemplary embodiment of FIG. 6. [Figure 7B] FIG. 7 is a cross-sectional view of the center of the clamping system in an exemplary embodiment mounted on a lift rod assembly of the steam dryer of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Because this is a patent document, broad rules of construction should generally be applied when reading it. Everything described and shown in this specification is an example of the subject matter that is included in the claims appended below. Any specific structural and functional details disclosed herein are merely for the purpose of explaining how to make and use the examples. Several different embodiments and methods not specifically disclosed herein may fall within the scope of the claims. Thus, the claims may be embodied in many alternative forms and should not be interpreted as being limited to only the examples described herein.

[0011] Membership terms such as "include," "comprise," "have," "comprising," and the like reflect the presence of the stated features, characteristics, steps, operations, elements, and / or components, but do not in themselves exclude the presence or addition of one or more other features, characteristics, steps, operations, elements, components, and / or groups thereof. Rather, an exclusive modifier such as "only" or "singular" may exclude the presence or addition of other subject matter in the modified term. The use of permissive terms such as "may" or "can" reflects the option that the modified term is not necessarily present, but the absence of permissive terms does not reflect compulsion. When listing items in the exemplary embodiments, conjunctions and inclusive terms such as "and," "with," and "or" include all combinations of one or more of the listed items without excluding them. The use of "including" is defined as "other" and indicates the inclusion of all other elements belonging to the same group of the preceding items in any "and / or" combination. As used herein, modifiers such as "first," "second," "another," and the like may be used to describe various items, but do not limit the modified items to a particular order. These terms are used only to distinguish one element from another, and the appearance of an ordinal number such as "second" or higher must indicate that multiple elements are present, without necessarily any difference or other relationship between those elements.

[0012] When an element is referred to as being "connected," "coupled," "on," "mounted," "fixed," or the like, in relation to another element, the element may be directly connected to the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly connected," "directly coupled," or the like, to another element, there are no intervening elements. Other words used to describe relationships between elements should be interpreted in a similar manner (e.g., "between" vs. "directly," "adjacent" vs. "directly adjacent," etc.). When describing electronic devices, terms such as "connection" and "communication connection" include all variations of non-human information exchange and routing between two devices, including intermediate devices, networks, etc., whether or not connected wirelessly. Similarly, when describing a computerized network, a term such as "real-time" has its clear meaning, including operations performed at speeds and quantities beyond human execution, including, for example, two events occurring directly successively or simultaneously within human sensing range over time that require discrete or separate human actions.

[0013] As used herein, the singular forms "a", "an", and "the" are intended to include both the singular and the plural unless expressly indicated otherwise. Indefinite articles such as "a", "an" introduce or refer to a modified term, including both previously introduced and otherwise, while definite articles such as "the" refer to the same previously introduced term. Relative terms such as "approximately" or "more than", and terms of degree such as "about" or "substantially" reflect a 10% variance in the modified value, or a full range of imprecision that still achieves the functionality of the modified term when understood by a skilled artisan in the technical context. Precision and non-variability are expressed with opposing terms such as "exactly".

[0014] As used herein, "axial" and "vertical" directions are those directions that are toward or below the major axis of the reactor, often in the direction of gravity. "Lateral" is perpendicular to the "axial" and is the side-to-side direction at a particular axial height, while "radial" is a particular lateral direction that is perpendicular to the long axis of the reactor and extends straight away from the long axis.

[0015] The structures and operations described below may occur in a different order than that depicted and / or noted in the figures. For example, two operations and / or figures shown in succession may in fact be performed simultaneously or in the reverse order, depending on the functionality / acts involved. Similarly, individual operations within the exemplary methods described below may be performed repeatedly, individually or sequentially to provide loops or other sequences of operations apart from the precise operations described below. Any embodiment or method having the features and functions described below, in any workable combination, should be presumed to fall within the scope of the exemplary embodiments.

[0016] The inventors have recognized that the lift structure of a steam dryer, including the lift rod assembly 20, is subjected to a large amount of flow-induced vibrations, in addition to other severe operating conditions, during operation within a nuclear reactor. The associated methods of operation of a steam dryer using a lift rod assembly will ultimately load the individual pieces of the rod (including the welds connecting the pieces), causing cracking, failure, and debris dispersion. Lateral forces and poor welds, such as from vibration, can cause the lift eye to rotate or become dislodged from the lift rod, and allow broken pieces to enter the reactor and surrounding environment. To solve these newly recognized problems and others, the inventors have developed the exemplary embodiments and methods described below to address these and other problems they have recognized with unique solutions enabled by the exemplary embodiments.

[0017] The present invention relates to a clamping system and method of use thereof in a nuclear reactor. In contrast to the present invention, the several exemplary embodiments and exemplary methods described below represent only a subset of the various different configurations that may be used as and / or in conjunction with the present invention.

[0018] FIG. 3 is a diagram of an exemplary embodiment of a lift rod repair clamping system 100 that can be used to repair and / or secure components within a nuclear reactor. As shown in FIG. 3, the exemplary embodiment of the clamping system 100 includes multiple independent clamping parts for surrounding and / or mounting to a component, such as the lift rod assembly 20 (FIGS. 1 and 2). For example, the upper lift lug clamp 110 may be a clamshell clamp with two annular halves sized to fit around the lift lugs 22 (FIG. 2) of the lift rod assembly 20, and the lower lift rod clamp 120 may be a clamshell clamp with two annular halves sized to fit around the lower lift rod 26 (FIG. 2) of the lift rod assembly 20. The clamps 110 and 120 may directly contact the lift lugs and lift rod and be secured to the lift lugs and lift rod by friction. Adhesives, lubricants, and / or intervening structures may also be used to provide the desired connections between clamps 110 and the lift rod assembly surfaces, and between clamps 120 and the lift rod assembly surfaces, as well as clearances between the clamp halves and other components within the individual clamps.

[0019] For example, as shown in FIGS. 3 and 5, the upper clamp 110 can have a substantially circular inner surface 114 with a diameter d22 that is shaped to fit the outer circumference of the lift lug 22 (FIG. 2). The lower clamp 120 can have a smaller substantially circular inner surface 124 with a smaller diameter d24 that is shaped to fit the outer circumference of the lower lift rod 26 (FIG. 2). For example, the diameter d22 can be about 5 inches and the diameter d24 can be about 3 inches, or any particular size that fits the outer diameter of the lift rod. Of course, elliptical, prismatic, and any other shaped surfaces can be used for the surfaces 114 and 124 to achieve the desired fit. Because the system 100 in the exemplary embodiment may be secured to a shoulder that covers a tack weld between the lift lug 22 and the lower lift rod 26 (FIG. 2), the transition surface 121 can be angled or close to the smaller diameter d24 of the lower clamp 120 to fit over the shoulder and cover the weld. These and other shapes enable clamp 110 and clamp 120 to substantially surround, enclose, and / or secure to a lift rod assembly within a nuclear reactor.

[0020] As shown in Figure 3, clamps 110 and 120 each include an adjustment hinge 111 and a tightening bolt 130 that allows them to be opened, closed, loosened and tightened around the lift rod assembly. The tightening bolt 130 may be captured within clamps 110 and 120 via bolt hinges 112 in clamps 110 and 120 to prevent them from completely separating from clamps 110 and 120. In this way, bolt 130 can pivot in and out of the capture of clamps 110 and 120 during installation and removal. If clamps 110 and 120 are made of non-separable pieces, the risk of a loose part getting into the reactor or a lost component that could interfere with installation may be reduced or minimized. Although clamps 110 and 120 are shown in FIG. 3 as clamshell type clamps with two annular halves, it will be understood that upper clamp 110 and lower clamp 120 can be other types of clamps such as a cinch clamp, a ratchet clamp, an orifice clamp, etc.

[0021] As shown in FIGS. 3 and 4, in the exemplary embodiment of the lift rod assembly repair clamping system 100, a gap 101 may be provided between the upper clamp 110 and the lower clamp 120. For example, the gap 101 may be a vertical gap of 0.05 inches at its narrowest point. The gap 101 may be complete, such that the upper clamp and the lower clamp 101 are completely separated without direct contact, or the gap 101 may be partial, such that the upper clamp 110 and the lower clamp 120 contact, join, or associate at a particular point. For example, the gap 101 may be filled with a resilient material, a spring material, or an O-ring material, a lubricant, a soluble separator, a damper structure, or the like. The gap 101 may be maintained by the clamps 110 and 120 secured to the underlying lift rod. If gap 101 is vertically complete or does not transmit significant forces vertically, gap 101 may prevent system 100 from being in the load path of the lift rod assembly by preventing the transmission of vertical loads between clamps 110 and 120 and / or the underlying lift rod portions. Thus, system 100 in the exemplary embodiment may be unloaded and not transmit forces during hold down operations, seismic events, and movement of the steam dryer via the lift rods.

[0022] The clamps 110 and 120 may be limited in relative rotation about a vertical axis. For example, the tab 115 of the upper clamp 110 and the recess 125 of the lower clamp 120 may limit the clamps 110 and 120 from rotating beyond a small amount, such as the thickness of the lateral gap 101 formed by the different sizes of the recess 125 and the tab 115. If the tab 115 is forced against the edge of the recess 125, such as by a lateral load or flow-induced vibration that affects the lift rod assembly underlying the clamps 110 and 120, the fixed nature of the clamps 110 and 120 may prevent further relative rotation. For example, due to sizing, the gap 101 may allow for about 2 degrees or less of relative rotation between the clamps 110 and 120 about the vertical center axis. Since the tab 115 and the recess 125 are not locked and fixed, no significant vertical loads can be generated between the clamps 110 and 120 while preventing relative rotation.

[0023] 6 and 7 show the lift rod repair clamp system 100 in an exemplary embodiment attached to a lift rod assembly by an exemplary installation method. For example, the system 100 may be attached to the shoulder between the lift lug 22 and the lower lift rod 26 to cover the tack weld 23 (FIG. 2). Either the clamp 110 or the clamp 120 may be independently opened and passed around the lift rod assembly 20 at any desired location, such as the shoulder. As shown in FIG. 7B, during some installations, the transition surface 121 of the lower clamp 120 fits around the tack weld 23 and the top of the clamp 120 abuts the lift lug 22. This containment of the weld 23 may limit damage to the weld 23 that may be present and limit any weld or other pieces that break off from the lift rod assembly 20 from entering the reactor fluid or causing a hazard. As shown in FIG. 6, during placement, the tab 115 may fit into the recess 125 while maintaining the gap 101. Alternatively, clamp 110 and clamp 120 may be attached together as a single unit with tabs 115 and recesses 125 aligned and gap 101 formed by a spring material, filler, or soluble separating agent.

[0024] Each bolt 130 may be tightened to a desired tension to close and secure the clamps 110 and 120 by friction or other fit on the lift rod assembly 20. FIG. 7A shows a front cross-sectional view of two bolts 130 of the swing bolt type rotated through the bolt hinge 112 into the captured portion of the body of the clamps 110 and 120. The bolts 130 may include threads that mate with counter threads in an outer nut 131 or an associated clamp body bore to tighten or loosen the bolts 130 and associated clamps upon rotation. The outer nut 131 may provide a gripping and crimpable surface for such rotation, while allowing its outer surface to deform against the bolts 130 as a crimp nut and lock onto the bolts 130 when the desired tension is reached. The spherical washer 132 may distribute the bearing load from the nuts 131 evenly across the clamp body to reduce binding during rotation. Conversely, outer nut 131 can be loosened by counter-rotation after cutting or expansion to loosen the associated clamp, bolt 130 can be pivoted out of the captured portion of the associated clamp, and clamp 110 or clamp 120, as desired, can be completely removed from the underlying structure.

[0025] Bolt 130, outer nut 131, spherical washer 132, and other tensioning components may all be inseparable from clamp 110 or clamp 120, such as via bolt hinge 112, so that no loose pieces, welded parts, and / or external parts are required for tightening, and a single tensioning tool or manual rotation may be used. Similarly, bolt 130 may be at a single shared front interface of clamp 110 and clamp 120, so that all installation and removal may be performed at a single point and potentially with a simple remote tool without further interfering with the steam dryers anywhere in the nuclear power plant. Of course, other tensioning structures may also be used with system 100 in the example embodiment, such as ratchets, simple bolt-nut arrangements, elastic or tightening materials, etc. that tighten and secure clamps 110 and 120 to the desired lift rod positions.

[0026] In some examples, the system 100 in the exemplary embodiment is shown with two clamps 110 and 120 mounted around the shoulders of the lift lugs of the steam dryer lift rod assembly, although it is understood that additional clamps may be used. Furthermore, rotational limits may be used between all such clamps in the exemplary embodiment, such as through successive tabs 115 and recesses 125. Similarly, while clamps 110 and 120 are shown in some examples as the same clamshell clamp configuration with two annular halves that open and close via bolt 130, clamps 110 and 120 may use different designs from one another and include unique tensioning features.

[0027] The clamping system 100 in the exemplary embodiment may be fabricated from materials compatible with the operating nuclear reactor environment, including materials that maintain their physical properties when exposed to high temperature fluids and radiation without becoming substantially radioactive, melting, becoming brittle, retaining / adsorbing radioactive particles, or otherwise substantially changing. For example, metals such as stainless steels, including austenitic stainless steels 304 or 316, XM-19, alloy 600, and the like, iron alloys, nickel alloys, zirconium alloys, and the like may be used for the components of the system 100. Similarly, direct connections between individual components and all other direct contact points may be lubricated and / or fabricated from alternating or other compatible materials to prevent sticking, fouling, metal-to-metal reactions, and the like.

[0028] Although several exemplary embodiments and methods have been described above, it should be understood by those skilled in the art that these examples may be modified through routine experimentation and without further inventive effort. For example, while clamps of different diameters are used in some of the exemplary systems, it is understood that clamps of other sizes and shapes may also be used in the exemplary systems. Modifications are not to be considered as departures from the spirit and scope of the exemplary embodiments, and all such modifications that are apparent to those skilled in the art are intended to be included within the scope of the following claims.

Claims

1. 1. A system for repairing a lift rod assembly of a steam dryer, the lift rod assembly having a lift lug extending at its longest dimension along a vertical axis and connected to a lift rod, the system comprising: a first clamp configured to be immovably fixed to the lift lug; and a second clamp configured to be immovably fixed to the lift rod, the first clamp and the second clamp having corresponding shapes to prevent relative rotation between the first clamp and the second clamp about the vertical axis and to allow relative translation between the first clamp and the second clamp along the vertical axis.

2. 2. The system of claim 1, wherein the lift rod passes through an internal bore in the lift lug, and the second clamp is configured to completely encircle and close the periphery of the internal bore.

3. 2. The system of claim 1, wherein the first clamp and the second clamp are clamshell clamps having a circular inner periphery configured to fit around an outer periphery of the lift rod assembly.

4. The system of claim 3 , wherein the first clamp has a different sized circular inner periphery than the second clamp.

5. 2. The system of claim 1, wherein the first clamp includes a tab extending vertically downward from a bottom of the first clamp and the second clamp includes a recess extending vertically downward from a top of the second clamp, the recess being larger than the tab such that the tab can move within the recess.

6. 2. The system of claim 1, wherein the first clamp includes a hinge and a bolt configured to clamp the first clamp, the bolt being movable relative to the first clamp and not removable from the first clamp.

7. 7. The system of claim 6, wherein the bolt is a swing bolt pivotable on a secondary hinge in the first clamp, the swing bolt being movable relative to the first clamp about an axis of the secondary hinge.

8. 7. The system of claim 6, wherein the bolt includes a threaded surface and a corresponding crimp nut configured to rotate on the threaded surface to tighten the first clamp and lock the first clamp in a tightened configuration.

9. The system of claim 6 , wherein the second clamp includes a hinge and a bolt that are in the same relative position and configuration as the hinge and the bolt of the first clamp.

10. 10. The system of claim 1 installed in a lift rod assembly repair, further comprising: a lift lug to which the first clamp is secured; and a lift rod to which the second clamp is secured and seated within the lift lug, the first clamp and the second clamp being separated by a vertical gap so as not to directly contact each other.

11. 11. The system of claim 10, further comprising a weld on the exterior of and joining the lift lug and the lift rod, the second clamp covering the weld so that a piece of the weld does not break and become detached from the system.

12. 1. A clamping system for fixing a component consisting of two rotatable joint components that are subject to vibration, comprising: a first clamp having a first internal bearing surface configured to mate with an outer surface of a first one of said two components; a second clamp having a second internal bearing surface having a different size than the first internal bearing surface and formed to match an outer surface of a second of the two components, the second clamp extending into the first clamp to prevent the first clamp and the second clamp from rotating more than two degrees relative to each other in any direction about a common vertical axis.

13. The clamping system of claim 12 , wherein the first clamp and the second clamp are not fixed to one another in a vertical direction.

14. The clamping system of claim 12 , wherein the first clamp and the second clamp each include a swing bolt and a nut configured to tighten the clamp.

15. 1. A method of repairing a lift rod assembly of a steam dryer, the lift rod assembly having a lift lug extending along a vertical axis and connected to a lift rod, the method comprising: clamping a first clamp around the lift lug to secure the first clamp to the lift lug; and clamping a second clamp around the lift rod to secure it to the lift rod, said clamping positioning the second clamp within the first clamp to prevent the first and second clamps and their underlying lift lugs and lift rods from rotating more than two degrees relative to each other in any direction on a vertical axis.

16. 16. The method of claim 15, wherein tightening the first clamp includes tightening a bolt within the first clamp, the bolt being movable relative to the first clamp and not removable from the first clamp.

17. The tightening of the first clamp further includes rotating a crimp nut on the bolt, the method comprising:

17. The method of claim 16, further comprising the step of locking the first clamp by deforming the crimp nut against the bolt.

18. 16. The method of claim 15, wherein the clamping creates a gap between the second clamp and the first clamp such that the second clamp does not directly contact the first clamp.

19. 16. The method of claim 15, wherein the lift rod assembly includes a weld that is external to and joins the lift lug and the rod section, and the clamping positions the second clamp to cover the weld such that a piece of the weld does not break away from the second clamp.

20. 20. The method of claim 19, wherein the first clamp and the second clamp are clamshell clamps having a circular inner periphery, and the second clamp includes a transition surface formed to include the weld but not directly contact the weld.

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