Metal working – Means to assemble or disassemble – Heat exchanger
Reexamination Certificate
1998-04-28
2001-11-20
Rosenbaum, I Cuda (Department: 3726)
Metal working
Means to assemble or disassemble
Heat exchanger
C029S890052, C029S890043
Reexamination Certificate
active
06317966
ABSTRACT:
The present invention generally relates to methods for installing a baffle in a tubular member. More particularly, this invention relates to methods and tools for inserting and securing a baffle within a tubular member, such as a manifold of a heat exchanger.
BACKGROUND OF THE INVENTION
Baffles are used in a variety of applications to direct the flow of fluids and gases through tubular members. One such application is for use in the manifolds of heat exchangers. Generally, heat exchangers include a pair of manifolds and a series of tubes interconnected between the manifolds. To optimize the efficiency of a heat exchanger, the flow of a heat transfer fluid, which may be gas or liquid, through the tubes is often controlled by placing baffles within the manifolds, such that separate and parallel flow regions can be established within the heat exchanger by appropriately routing the fluid through the tubes of the heat exchanger.
The prior art has suggested various methods and tools for installing baffles, an example of which is U.S. Pat. No. 5,052,478 to Nakajima et al. Nakajima et al. teach the insertion of partitioning plates through circumferential slots formed in the wall of a heat exchanger manifold. A notable disadvantage of this method is that inserting plates through the manifold wall does not itself positively secure the plates to the manifold. Therefore, the plates must be soldered, brazed or welded to the manifold, or an additional fastening member is required to secure the plates. However, attaching the plates with solder and the like can contaminate the interior of the manifold with foreign matter, such as solder flux. In addition, the presence of slots in the manifold wall substantially weakens the manifold, reducing its capacity to withstand numerous temperature and pressure cycles.
As such, others in the art have proposed various other methods and tools for installing a baffle within a manifold without compromising the structural integrity of the manifold. For instance, commonly-assigned U.S. Pat. No. 4,762,152 to Clausen teaches a tool for installing a baffle within a manifold so as to completely avoid the necessity of cutting slots in the manifold. Baffles installed in this manner are generally cup-shaped, with a closed base and an axially-extending annular sidewall that forms a cavity with the base. The radial thickness of the sidewall increases in thickness in a direction away from the base. These baffles are installed with a tool having a head adapted to be inserted into the recess of the baffles. Once the baffle is appropriately positioned within the manifold, the tool is retracted from the recess, forcing the sidewalls radially outward as the tool is withdrawn. In so doing, the sidewall is forced against the inner surface of the manifold, thus plastically deforming the baffle and manifold so as to secure the baffle in place.
While Clausen teaches an uncomplicated installation tool, others in the prior art have resorted to more complicated tool designs, as evidenced by U.S. Pat. No. 5,165,470 to Maekawa et al., which teaches an installation tool having a narrow shaft threadably connected to a radially larger head that remains within the baffle after installation. The tool must be rotated during installation of the baffle, which considerably complicates the installation process. Further complicating the installation method of Maekawa et al. is the requirement of a stop member that must be inserted with the installation tool to prevent the baffle from being inadvertently removed with the tool. Without the stop member, a newly installed baffle would tend to be removed or at least dislocated while the tool is being retracted. Finally, tools of the type taught by Maekawa et al. can be difficult to initially insert into a baffle, particularly if it is desirable to use such tools on an automated assembly line.
Other installation methods and tools have been suggested by which the necessary radial outward force required to secure a baffle to the wall of a manifold is created by a forward-moving shaft rather than a rearward-moving tool of the type taught by Maekawa et al. and Clausen. For example, Japanese Application No. 63-239062 to Nishishita teaches a tool for installing a bowl-shaped baffle having a closed base and an axially-extending, radially-diverging sidewall of uniform thickness. To secure the baffle in place, this tool applies a radially outward force on the baffle's sidewalls with a radial arrangement of fingers that are mechanically forced radially outward with a rod. The bowl-shaped baffle employed by Nishishita necessarily has a larger diameter than the manifold passage due to the rather mechanically inefficient manner in which the baffle is only locally expanded by the radial fingers. However, this shape renders the baffle difficult to temporarily secure on the tool prior to insertion into the manifold, and also resists and complicates the initial insertion of the baffle into the manifold. Also, localized expansion of the baffle sidewall with the radial fingers can allow leakage if the diameter of the baffle is compromised to facilitate its insertion into the manifold. Finally, such baffles are more prone to becoming dislodged due to the limited extent to which the sidewall is deformed to secure the baffle in place.
Accordingly, it can be seen that an improved method is needed for installing and securing a baffle in a tubular member, such as a heat exchanger manifold. More particularly, such a method should provide for secure attachment of a baffle without compromising the structural integrity of the manifold, employ an installation tool that is capable of readily and securely gripping the baffle prior to and during installation, enable the baffle to be shaped to permit the tool to readily grasp the baffle and thereby facilitate insertion of the baffle into the manifold, provide for uniform securement of the baffle against the walls of the manifold, and enable the tool to be removed without inadvertently removing the baffle with the tool.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a method for installing and securing a baffle in a tubular member while maintaining the structural integrity of the tubular member.
It is a further object of this invention to provide an installation tool that is capable of securely gripping the baffle prior to its installation in the tubular member.
It is another object of this invention that such a tool secures the baffle to the tubular member by uniformly deforming the sidewall of the baffle.
It is yet another object of this invention that the tool is configured to avoid inadvertently removing the baffle from the tubular member during removal of the installation tool.
In accordance with this invention, a method is provided that employs an installation tool for installing and securing a baffle to an interior wall surface of a tubular member, such as a heat exchanger manifold. The method and tool are adapted to use a baffle having a closed base that acts to obstruct the flow of a fluid within the tubular member, and further having a sidewall extending axially from the perimeter of the base so as to form a recess in the baffle. Advantageously, the tool is adapted to work well with a baffle whose sidewall has a substantially constant radial thickness and diameter, thereby facilitating installation and securement of the baffle with the tube member and promoting a fluid-tight seal with the tubular member wall.
The installation tool of this invention is generally composed of a sleeve having an elastically and radially deformable end. In a preferred embodiment, the sleeve is formed to have longitudinally-extending cantilevered members adapted to be elastically bent radially outward. In particular, radially outward deformation of the sleeve enables the sleeve to both securely grip the baffle as the baffle is being inserted into the tubular member, and then plastically deform the sidewalls of the baffle in order to secure the baffle to the wall of the tubular member. As such, the sleeve is configured
Halbig David Michael
Insalaco Jeffrey Lee
Johnson William Marv
Cuda Rosenbaum I
Hartman Domenica N. S.
Hartman Gary M.
Norsk Hydro a.s.
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