Patent Publication Number: US-2010116478-A1

Title: Displaceable baffle for a heat exchanger and method for reducing vibration for the same

Description:
FIELD OF THE INVENTION 
     This invention relates to tube bundle devices such as heat exchangers, condensers and similar fluid-handling equipment with collections of tubes or rod-like elements, for example, in devices such as nuclear reactors, chemical reactors, electrical heaters, or any collection of parallel cylindrical shapes that has a fluid flow passing over the tubes or other elements. In particular, the present invention relates to a displaceable baffle or support structure for use in connection with the bundle to provide support to the individual tubes within the bundle and reduce vibration. The present invention is also directed to a method for reducing vibration in a tube bundle in a heat exchanger. 
     BACKGROUND OF THE INVENTION 
     Tube bundle equipment such as shell and tube heat exchangers and other similar fluid handling devices such as flow dampers and flow straighteners utilize tubes organized in bundles to conduct the fluids through the equipment. In such tube bundles, there is typically fluid flow both through the inside of the tubes and across the outside of the tubes. The configuration of the tubes in the bundle is set by the tubesheets into which the tubes are set. One common configuration for the tubes is the rectangular or square formation with the tubes set in aligned rows with tube lanes (the straight paths between the tubes) between each pair or rows, aligned orthogonally to one another. In this formation, each tube is adjacent to eight other tubes except at the periphery of the tube bundle and is directly opposite a corresponding tube across the tube lane separating its row from the two adjacent rows. In the triangular tube formation, the tubes in alternate rows are aligned with one another so that each tube is adjacent to six other tubes (the two adjacent tubes in the same row and four tubes in the two adjacent rows). 
     Increases in throughput in existing exchangers are often desired either to reduce capital cost by reducing equipment size or to increase productivity factors. A common limiting factor experienced when evaluating the increase of rates in a heat exchanger is the potential for flow-induced vibration damage of the tubes. Fluid flow patterns around the tubes may give rise to flow-induced vibrations of an organized or random oscillatory nature in the tube bundle and in the case of devices such as heat exchangers in which heat transfer takes place between the tubes and the surrounding fluid, the changes in the velocity, temperature and density of the fluid as it circulates and flows around the tubes may increase the likelihood of vibration. If these vibrations reach certain critical amplitudes, damage to the bundle may result. Tube vibration problems may be exacerbated if the heat exchanger equipment is retubed with tubes of a different material to the original tubes, for example, if relatively stiff materials are replaced with lighter weight tubes. Flow-induced vibration may also occur when equipment is put to more severe operating demands, for example, when other existing equipment is upgraded and a previously satisfactory heat exchanger, under new conditions, becomes subject to flow-induced vibrations. Vibration may even be encountered tinder certain conditions when a heat exchanger is still in the flow stream but without heat transfer taking place as well as in other bundle devices with collections of rods or rod-like elements in a flow stream with or without heat transfer. 
     A number of different equipment designs have evolved to deal with the problem of tube vibration. One example is the rod baffle design. Rod baffle heat exchangers are shell and tube type heat exchangers utilizing rod baffles to support the tubes and secure them against vibrations. The term “baffle” refers to the cages, placed every 15 cm or so along the length of the tube bundle, in which the ends of a plurality of support rods are connected to form a cage-like tube support structure; hence the term “rod baffle”. Rod baffle exchangers, however, tend to be approximately 30 to 40% more expensive than conventional shell-and-tube exchangers and there have been situations where tube bundle devices of this kind have failed owing to flow-induced vibrations. The rod baffles must have very precise dimensions. If the rods in rod baffles are slightly undersized, tube chatter will occur. If the rods are slightly oversized, tube loading will be very difficult and expensive. Rod baffle heat exchangers are described, for example, in U.S. Pat. Nos. 4,342,360 to Gentry et al.; 5,388,638 to Gentry; 5,553,665 to Gentry; and 5,642,778 to Gentry. 
     As described in U.S. Pat. No. 5,553,665, certain applications of the rod baffle design such as gas-compression applications may benefit from longitudinal-flow, with shell-side pressure losses to be minimized. Reduction in shell-side pressure losses may be accomplished by increasing rod baffle spacing, thereby reducing the number of rod baffles, or by decreasing the number of tubes by increasing the tube pitch dimension, i.e., the distance between two adjacent rows of tubes as measured from the center of the tubes. Increasing baffle spacing is usually not an attractive option, since increased baffle spacing increases the likelihood of flow-induced tube vibration occurrence. This rod baffle design represents an attempt to deal with the pressure drop problems of the rod baffle configuration. 
     An alternative design is the “Eggcrate” support design. This, however, is even more expensive than the rod baffle design. Like the rod baffle, the eggcrate is also susceptible to tube chatter that could lead to tube failure. Chatter is the motion of a tube hitting the tube supports because of a gap between the support and the tube outside diameter. The gap is required to allow for inserting the tubes through the eggcrate support when the bundle is being constructed. 
     Besides good equipment design, other measures may also be taken to reduce tube vibration. Tube support devices or tube stakes as these support devices are commonly known (and referred to in this specification) may be installed in the tube bundle in order to control flow-induced vibration and to prevent excessive movement of the tubes. A number of tube supports or tube stakes have been proposed and are commercially available. U.S. Pat. No. 4,648,442 to Williams, U.S. Pat. No. 4,919,199 to Hahn, U.S. Pat. No. 5,213,155 to Hahn and U.S. Pat. No. 6,401,803 to Hahn, for example, describe different types of tube stake or tube support which can be inserted into the tube bundle to reduce vibration. 
     Improved tube stakes are also shown in U.S. Pat. No. 7,032,655 to Wanni et al. entitled “Anti-Vibration Tube Support.” The use of the tube stakes taught by Wanni et al. have been found to be particularly effective in reducing vibration in tube bundles. These are especially useful in retrofitting, existing bundles. Co-pending and commonly assigned U.S. patent application Ser. No. 11/905,694 to Wanni et al., entitled “Reduced Vibration Tube Bundle Device Having Slotted Baffles,” the disclosure of which is incorporated specifically herein by reference, discloses the use of slotted baffles to support the tubes % within the tube bundles, as shown in  FIGS. 1-4 . Tube support stakes, like those disclosed in U.S. Pat. No. 7,032,655 are used to deflect the individual tubes into contact with the slotted baffles such that the baffles in combination with the stakes support the tubes and reduce vibration, as shown in  FIG. 1 . There, however, is a need to reduce vibration in tubes bundles without the use of the tube stakes especially for use, for examples in new tube bundles. 
     SUMMARY OF THE INVENTION 
     It is an aspect of the present invention to provide a tube bundle device (e.g., a heat exchanger) having at least one displaceable baffle which supports the tubes in the bundle device. The use of the terminology is used by way of example. It is contemplated that the present invention is not limited to tubes; rather, it is contemplated that the rods and other heat transfer or fluid flow elements may be employed and are considered to be veil within the scope of the present invention. 
     It is an aspect of the present invention to provide an improved tube bundle device, which provides increased tube support to reduce vibration. The tube bundle device includes a housing, and a tube bundle located within the housing. The tube bundle has a plurality of tubes arranged parallel to one another in tube rows. The tubes may be arranged in a conventional rectangular configuration or a conventional triangular configuration. The tube bundle device includes at least one displaceable support baffle. Each displaceable support baffle has a plurality of apertures formed therein. The apertures are sized to receive at least one tube therethrough. Various aperture configurations are contemplated. The apertures may be sized to receive a single tube therethough. The apertures may be formed as elongated slots to receive multiple tubes as disclosed, for example, in co-pending U.S. patent application Ser. No. 11/905,694 filed on Oct. 3, 2007, entitled “Reduced Vibration Tube Bundle halving Slotted Baffles,” the disclosure of which is incorporated by reference in their entirety. The apertures may be formed as elongated slots formed from elongated rods or bars secured to a cage, as disclosed, for example, in U.S. Pat. No. 7,219,718 and U.S. Pat. No. 7,073,575, both entitled “Reduced Vibration Tube Bundle,” the disclosures of WHICH are incorporated by reference in their entireties. 
     In accordance with the present invention, each displaceable support baffle has at least a first portion and a second portion, whereby the portions are selectively displaceable between a first loading position to facilitate positioning of the displaceable support baffle on the tube bundle and a second installed position causing deflection of the tubes passing through the plurality of apertures. At least one first fastener is provided to secure or maintain the portions in the first loading position. After locating the displaceable support baffle in the desired location along the axis of the tube bundle, the at least one first fastener is either loosened or removed to permit displacement of the portions with respect to each other to the second position. The first fasteners ma) be clamps, screws, bolts or any other suitable fastener that maintains the portions in the first position while being installed, but can be removed to permit displacement of the portions to the second position. It is contemplated that the portions can be either brought closer together or spread further apart in the second installed position provided that the tubes passing through the displaceable support baffle are deflected. At least one second fastener is provided to secure or maintain the portions in the second installed position. The second fasteners may be clamps, screws, bolts, welds or any other suitable fastener that maintains the portions in the second installed position. The present invention is not intended to be limited to a first portion and a second portion, rather any number of portions greater than two are contemplated provided the portions can be displaced relative to each other in order to provide the necessary deflection of the tubes within the bundle. 
     In accordance with another aspect of the present invention, at least one insert is provided between the portions to provide the necessary spacing between the portions such that the tubes are deflected by the portions. The second fasteners are then used to secure the portions and the inserts in their proper orientation. 
     In accordance with another aspect of the present invention, the displaceable support baffle is used in conjunction with at least one fixed baffle. Each fixed baffle having a plurality of apertures that are sized to receive at least one of the tubes therethrough. The at least one fixed baffle and the at least one displaceable support baffle are spaced along the longitudinal axis of the tube bundle. Preferably, each displaceable support baffle is spaced from an adjacent fixed baffle. With such an arrangement when the displaceable support baffles are located in their second installed position, the tubes are deflected a sufficient amount such that the tubes also contact the fixed baffle further stabilizing the tubes within the bundle and reducing vibration. 
     In accordance with yet another aspect of the present invention, a displaceable support baffle for use in supporting a plurality of tubes in a tube bundles is disclosed. The displaceable support baffle includes at least a first plate and a second plate. Each plate having a plurality of apertures formed therein. The displaceable support bathe having at least one first fastener assembly for securing the plates together in a first loading position. The displaceable support baffle further includes at least one second fastener assembly for securing the plates together in a second installed position. 
     It is another aspect of the present invention to provide a method of supporting a tube bundle having a plurality of tubes arranged parallel to one another in tube rows and longitudinal axis extending in a direction generally parallel to the plurality of tubes. The method includes locating at least one displaceable support baffle on the tube bundle along the longitudinal axis. Each displaceable support baffle having a plurality of apertures formed therein that are sized to receive at least one of the tubes therethrough. Each baffle having two or more portions, wherein each portion of the some of the plurality of apertures located therein. The method further includes displacing the portions with respect to each other to an installed position and securing, the portions in the installed position. The tubes passing through the displaceable baffles are deflected when the portions are displaced with respect to each other. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described in conjunction with the accompanying drawings in which like reference numerals describe like elements and wherein: 
         FIG. 1  is a schematic view of a tube bundle having at least one displaceable support baffles in accordance with an embodiment of the present invention; 
         FIG. 2  is a schematic view of a displaceable support baffle in accordance with an embodiment of the present invention; 
         FIG. 3  is a variation of the displaceable support baffle of  FIG. 2 ; 
         FIG. 4  is another variation of the displaceable support baffle of  FIG. 2 ; 
         FIG. 5A  is yet another variation of the displaceable support baffle of  FIG. 2  having a plurality of horizontally arranged slots in accordance with the present invention; 
         FIG. 5B  is another variation of the displaceable support baffle of  FIG. 5A  having more than one parallel partition lane; 
         FIG. 6  is a side view of a tube bundle device in accordance with the present invention having a displaceable support baffle in a loading position; 
         FIG. 7  is a side view of a tube bundle device of  FIG. 6  having the displaceable support baffle in one installed position in accordance with the present invention; 
         FIG. 8  is a schematic view of a displaceable support baffle having a clamping device in accordance with the present invention; 
         FIG. 9  is a schematic view of a displaceable support baffle having another clamping device in accordance with the present invention; 
         FIG. 10  is a side view of a tube bundle device of  FIG. 6  having the displaceable support baffle in another installed position in accordance with the present invention; 
         FIG. 11  is a schematic view of a displaceable support baffle having a plurality of openings sized to receive a tube therein in accordance with the present invention; 
         FIG. 12  is a schematic view of a displaceable support baffle having a plurality of rods forming a plurality of slots sized to receive tubes therein in accordance with the present invention; 
         FIG. 13  is a schematic view of fixed support baffle having vertical slots for use in the tube bundle in accordance with the present invention; 
         FIG. 14  is a schematic view of fixed support baffle having horizontal slots for use in the tube bundle in accordance with the present invention; and 
         FIG. 15  is a schematic view of blocking baffle for use in the tube bundle in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention will now be described in greater detail in connection with the following figures. Applicant notes that the terminology horizontal and vertical when used in connection with the present invention is intended as a point of reference to describe the orientation of the individual components of the baffles with respect to the other components of the baffles. The terminology is not intended to describe the orientation of the baffles or components, which make up the baffles within the heat exchanger. It is contemplated that the tube bundle device  1  can have one of several orientations when in use. Thus the tube bundle device can be in general oriented horizontally, vertically or any angle relative to the horizontal. 
     A tube bundle having, a plurality of spaced baffles is illustrated in  FIG. 1 . The tube bundle  10  is part of a tube bundle device  1  (e.g., a heat exchanger or other suitable heat transfer component). The tube bundle  10  includes a plurality of parallel tubes  11 , which extend between a pair of tubes sheets  13  and  14 . The tube bundle  10  is fitted into the surrounding shell or housing  20  of the tube bundle device  1 . Typically fluid flow occurs through both the inside of the tubes  11  and within the shell  20  across the outside of the tubes  11 . The tube bundle  10  is provided with baffles to reduce flow-induced vibration within the tube bundle  10  and direct the flow of the fluid towards the tubes  11  away from the shell  20 . 
     A displaceable support baffle  300  is illustrated in  FIG. 2 . The displaceable baffle  300  includes a plurality of apertures that are sized to receive the tubes  11  to reduce vibration. The displaceable baffle  300  includes a plurality of slots  36 . The slots  36  are arranged to correspond to the rows of the tubes  11  in the bundle  10 . A plurality of vertically extending ribs  37  are provided on the baffle  300 . Each rib  37  extends vertically between the slots  36 . Each rib  37  preferably has a thickness that is slightly smaller than the spacing between adjacent tubes  11  in the tube bundle  10 . The present invention is not limited to vertical slots; rather, horizontal slots  46 , as illustrated in  FIGS. 5A and 5B  are considered to be well within the scope of the present invention. With horizontally extending slots  46 , a plurality of horizontally extending ribs  47  are provided. Each rib  47  extends horizontally between the slots  46 . Each rib  57  preferably has a thickness that is slightly smaller than the spacing between adjacent tubes  11  in the tube bundle  10 . The present invention, however, is not intended to be limited to the use of vertical slots  36  or horizontal slots  46 , rather, other apertures are contemplated including but not limited to horizontal slots, openings  371  sized to receive a single tube  11 , as shown in  FIG. 11 , and elongated openings  372  formed from elongated bars or rods  373  secured to a cage  374 , as shown in  FIG. 12 . It is contemplated that the use of openings  371  for receiving individual tubes  11  therethrough may be the preferred aperture configuration. 
     A blocking region  34  around the perimeter is configured to redirect any bypass flow from between the outermost tubes  11  and the inside diameter of the shell  20  inwardly towards the tubes  11 . Vertical slots  316  receive the tubes  11  therein. The baffle  30  includes a plurality of notches  32  and  33  formed therein. The notches  32  are sized to receive a tie bar  5  therein. The notches  33  are sized to receive a skid bar  6  therein. The skid bar  6  is provided to ensure support during insertion of the tube bundle  10  into the shell  20 . The notches  32  and  33  ensure that the baffles  300  are maintained in the proper orientation. The tie bars  5 , the skid bars  6 , the displaceable baffles  300 , the fixed baffles  30 ,  40  (if utilized) and blocking baffles  60  (if utilized) together form a rigid cage, which facilitates the insertion of the tubes  11  of the bundle  10  into the shell  20 . 
     Typically, the tube bundle  10  includes at least one partition lane, which separates the tubes  11  within the tube bundle  10  into discrete groups. The partition lanes do not include any tubes  11 . The partition lanes may have horizontal and vertical orientations. Fluid flowing through the partition lanes does not contact the heat transfer surfaces of the tubes  11 . As such, it is desirable to redirect the flow of fluid within the bundle  10  away from the partition lanes towards the tubes  11  to improve heat transfer. The displaceable baffle  300  includes at least one partition lane blocking, area  35  and  310  to redirect the flow of fluid within the shell of the heat exchanger  1  towards the tubes  11  of the tube bundle  10 . The plurality of apertures is located on opposing sides of the blocking areas  35  and  110 . 
     The displaceable baffle  300  in accordance with an aspect of the present invention is divided into at least two separate portions  320  and  330  along partition lane  301  in partition lane blocking area  310 . The partition lane  301  is formed by cutting the baffle  300  into two sections. This can be accomplished by laser cutting or other suitable cutting method. The original shape of the baffle  300  (i.e., before cutting the baffle into two or more sections) may be slightly larger than the desired shape such that the baffle  300  after it is cut into two sections and is in an installed position has an outer perimeter that is consistent with the size of the inner perimeter of the shell  20 . It is also contemplated that the portions  320  and  330  can be formed as separate sections. The portions  320  and  330  are secured together for loading onto the tube bundle  10  such that the baffle  300  can be properly located at the desired location on the tube bundle  10 . A removable clamping assembly  350 , as shown in  FIG. 8 , may be used to secure the portions together for purpose of properly installing the baffle  300 . Once the baffle  300  is properly located and the tubes are loaded, the clamping assembly  350  is removed. The baffle  300  has an orientation as illustrated in  FIG. 6 . The tubes  11  are received within the apertures and a small space  360  exists between the portions  320  and  330 . 
     Stiffening of the tubes  11  in the bundle  10  to reduce vibration can be accomplished in one of two ways. Once the baffles  300  and other baffles described in greater detail below are properly located on the tube bundle  10  and the clamping assemblies  350  have been removed, the portions  320  and  330  can be moved closer together to a position shown in  FIG. 7  or  FIG. 9 . In such an arrangement, the apertures in the baffle  300  contact the tubes  11  causing an inward deflection of the tubes  11 . This deflection of the tubes causes stiffening, which reduces vibration. The portions  320  and  330  can be secured together using an appropriate weld along the partition lane  301 , an appropriate clamping device  370 , a nut and bolt fastener assembly  380  or any other suitable fastener provided such fastener maintains the portions  320  and  330  in their proper installed position during operation of the heat exchanger  1 . 
     Alternatively, once the battles  300  and other baffles are properly located on the tube bundle  10  and the clamping assemblies  350  have been removed, the portions  320  and  330  can be moved further apart to a position shown in  FIG. 10 . In such an arrangement, the baffle  300  may have an original shape that is slightly smaller such that when it is in the installed position, the outer perimeter of the baffle  300  substantially corresponds to the inner perimeter of the shell. The slight movement of the two portions  320  and  330  is achieved by slightly moving the two portions away from each other, through the use of cranes, jacks or the like, and placing a properly formed insert  390  (which may be formed from a strip of metal) in the space  391  between the two portions  320  and  330  of the baffle  300 . Once the force exerted by the crane or the jacks is removed, the force exerted by the tubes  11  would keep the insert  390  in place; likewise, the same force would create a bending force on the tubes and thereby stiffen them. The two portions can be welded to each other or secured to each other with another set of clamps to provide additional rigidity during bundle handling. In such an arrangement, the apertures in the baffle  300  contact the tubes  11  causing an outward deflection of the tubes  11 . The portions  320  and  330  can be maintained in such an orientation using an insert  390 . The portions  320  and  330  may be welded to the insert  390 . It is also contemplated that a clamping device  370 , or any other suitable fastener may be used to secure the portions  320  and  330  provided such fastener maintains the portions  320  and  330  in their proper installed position. It is important to note that the thickness of the insert  390  should be slightly larger than the thickness of the space  391  cut in the baffle  300 . For example, if the slot  391  cut is 3 mm wide, the insert  390  may be about 6 or 7 mm thick. 
     A displaceable support baffle  400  is illustrated in  FIG. 5A . The displaceable baffle  400  includes a plurality of apertures that are sized to receive the tubes  11  to reduce vibration. The displaceable baffle  400  includes a plurality of slots  46 . The slots  46  are arranged to correspond to the rows of the tubes  11  in the bundle  10 . A plurality of horizontally extending ribs  47  are provided oil the baffle  400 . Each rib  47  extends horizontally between the slots  46 . Each rib  47  preferably has a thickness that is slightly smaller than the spacing between adjacent tubes  11  in the tube bundle  10 . The slots  46  can be replaced with openings  361  or elongated openings  372 , as described above. 
     A blocking region  44  around the perimeter is configured to redirect any bypass flow from between the outermost tubes  11  and the inside diameter of the shell  20  inwardly towards the tubes  11 . Horizontal slots  46  receive the tubes  11  therein. The baffle  400  includes a plurality of notches  32  and  33  formed therein. The notches  32  are sized to receive a tie bar  5  therein. The notches  33  are sized to receive a skid bar  6  therein. The skid bar  6  is provided to ensure support during insertion of the tube bundle  10  into the shell  20 . The notches  32  and  33  ensure that the baffle  400  is maintained in the proper orientation. The tie bars  5 , the skid bars  6 , the displaceable baffles  300  and  400 , the fixed baffles  30 ,  40  (if necessary) and blocking baffles  60  (if necessary) together form a rigid cage, which facilitates the insertion of the tubes  11  of the bundle  10  into the shell  20 . 
     The displaceable baffle  400  includes at least one partition lane blocking area  45  to redirect the flow of fluid within the shell of the heat exchanger  1  towards the tubes  11  of the tube bundle  10 . The plurality of apertures is located on opposing sides of the blocking areas  45 . The displaceable baffle  400  in accordance with an aspect of the present invention is divided into at least two separate portions  420  and  430  along partition lane  401  in partition lane blocking area  45 . The partition lane  401  is formed by cutting the baffle  400  into two sections. This can be accomplished by laser cutting or other suitable cutting method. Like baffle  300 , the original shape of the baffle  400  (i.e. before cutting the baffle into two or more sections) may be slightly larger than the desired shape such that the baffle  400  after it is cut into two sections and is in an installed position has an outer perimeter that is consistent with the size of the inner perimeter of the shell  20  when the portions  420  and  430  are moved closer together. Like baffle  300 , the original shape may be slightly smaller when the portions  420  and  430  are moved further apart in the installed position. In some circumstances, the heat exchanger  1  may not have a partition lane. This may occur in a single tube pass heat exchanger. In such an arrangement, it is desirable to include an artificial partition lane on the displaceable baffle (i.e., the width of the tube lane is increased) in order to permit the cutting of the baffle into two or more sections along the partition lane  401 . It is desirable to include all artificial partition lane when there are no partition lanes (e.g., an exchanger with a single tube pass) or a partition lane is desired where one does not exist.  FIG. 5B  illustrates a displaceable baffle  700  having more than one partition lanes  701 ,  702  and  703 , which divide the baffle  700  into portions  710 ,  720 ,  730  and  740 . 
     The portions  420  and  430  are secured together for loading onto the tube bundle  10  such that the baffle  400  can be properly located at the desired location on the tube bundle  10 . A removable clamping assembly  350 , as shown in  FIG. 8 , may be used to secure the portions together for purpose of properly installing the baffle  400 . The baffle  400  has an orientation as illustrated in  FIG. 6 . The tubes  11  are received within the apertures and a small space  360  exists between the portions  420  and  430 . Once the baffle  400  is properly located and the tubes  11  are loaded, the clamping assembly  350  is removed. 
     Stiffening of the tubes  11  in the bundle  10  to reduce vibration can be accomplished in one of two ways. Once the baffles  400  and other baffles described in greater detail below are properly located on the tube bundle  10 , tubes  11  are loaded and the clamping assemblies  350  have been removed, the portions  420  and  430  can be moved closer together to a position shown in  FIG. 7  or  FIG. 9 . In such an arrangement, the apertures in the baffle  400  contact the tubes  11  causing an inward deflection of the tubes  11 . This stiffens the tubes  11  to reduce vibration. The portions  420  and  430  can be secured together using an appropriate weld along the partition lane  401 , an appropriate clamping device  370 , a nut-and-bolt fastener assembly  380  or any other suitable fastener provided such fastener maintains the portions  420  and  430  in their proper installed position during operation of the heat exchanger  1 . 
     Alternatively, once the baffles  400  and other battles are properly located on the tube bundle  10 , tubes  11  are loaded, and the clamping assemblies  350  have been removed, the portions  420  and  430  can be moved further apart to a position shown in  FIG. 10 . In such an arrangement, the baffle  400  may have an original shape that is slightly smaller such that when it is in the installed position, the outer perimeter of the baffle  400  substantially corresponds to the inner perimeter of the shell. The slight movement of the two portions  420  and  430  is achieved by slightly moving the two portions away from each other, through the use of cranes, jacks or the like, and placing a properly formed insert  390  (which may be formed from a strip of metal) in the space  391  between the two portions  420  and  430  of the baffle  400 . Once the force exerted by the crane or the jacks is removed, the force exerted by the tubes  11  would keep the insert  390  in place; likewise, the same force would create a bending force on the tubes and thereby stiffen them. The two portions can be welded to each other or secured to each other with another set of clamps to provide additional rigidity during bundle handling. In such an arrangement, the apertures in the baffle  400  contact the tubes  11  causing an outward deflection of the tubes  11 . The portions  420  and  430  can be maintained in such an orientation using an insert  390 . The portions  420  and  430  may be welded to the insert  390 . It is also contemplated that a clamping device  370 , or any other suitable fastener may be used to secure the portions  420  and  430  provided such fastener maintains the portions  420  and  430  in their proper installed position. 
     In accordance with the present invention, the displaceable baffles  300  and  400  are not limited to two displaceable portions  320 ,  330  and  420 ,  430 ; rather, two or more displaceable portions are considered to be well within the scope of the present invention. A baffle  500  having three displaceable portions is illustrated in  FIG. 3 . Baffle  500  includes an additional partition lane  302 . A baffle  600  having four displaceable portions is illustrated in  FIG. 4 . Baffle  600  further includes an additional partition lane  303 . The displaceable portions are displaceable with respect to each other and can be secured in the proper loaded position in the manner described above. Other configurations are considered to be well within the scope of the present invention. Furthermore, various aperture configurations are considered to be suitable for use with the baffles  500  and  600 . When the plurality of apertures are slots, the partition lane  401  is generally parallel to the slots such that the slots can displace the tubes  11  when the portions are displaced, as shown in  FIGS. 2 and 4 . When more than one partition lane (e.g. as shown in  FIGS. 3 ,  4 ,  5 B) is provided the aperture configuration must permit displacement of the tubes when the portions are displaced relative to each other. In  FIG. 5B , the partition lanes  701 ,  702  and  703  are parallel to each other. With such an arrangement, the apertures may be elongated slots that extend parallel to the partition lanes such that displacement of the portions  710 ,  720 ,  730  and  740  will cause the proper deflection of the tubes. Elongated slots extending perpendicular to the partition lanes would not cause the proper deflection of the tubes. In those circumstances, the use of an opening  371  may be the most appropriate aperture when more than one direction of displacement is contemplated. 
     In accordance with the present invention, the displaceable baffles  300  and  400  may be spaced along the length of the tube bundle  10  to reduce vibration. It is also contemplated that the displaceable baffles may be located only at those locations where vibration reduction is needed (e.g., at the end portions of the bundle). The present invention is not intended to be limited to the use of displaceable baffles  300  and  400  alone. 
     In accordance with the present invention, the displaceable baffles  300  and  400  may be used in connection with at least one fixed baffle  30  or  40 , as shown in  FIGS. 13 and 14 , and at least one blocking baffle  60 , as shown in  FIG. 15 . A fixed baffle  30  having slots is illustrated in  FIG. 13 . While the fixed baffle  30  is illustrated with vertical slots, the present invention is not intended to be limited to baffles only having slots; rather, other configurations, as described above in connection with the displaceable baffle  300  are considered to be well within the realm of the present invention. The fixed baffle  30  has a plurality of vertical slots  36  that provide support for the tubes  11  to reduce vibration. A blocking region  34  is configured to redirect any bypass flow from between the outermost tubes  11  and the inside diameter of the shell  20  inwardly towards the tubes  11 . The vertical slots  36  receive the tubes  11  therein. The baffle  30  includes a plurality of notches  32  and  33  formed therein. The notches  32  are sized to receive a tie bar  5  therein. Generally, tie bars and skid bars are welded to the baffles before loading the tubes. In the case of the present invention, this would not be appropriate for the displaceable baffles. Instead, the tie bars and skid bars would be welded to the displaceable baffles after loading the tubes and after displacing the baffle portions. The fixed baffles and blocking baffles, if used, can be welded to the tie bars and skid bars prior to the loading of the tube to provide sufficient rigidity to the bundle cage. The present invention is not limited for use with tie bars; rather, the use of conventional tie rods  380 , as shown in  FIG. 11 , may be used. When tie rods  380  are utilized, the tie rods may be allowed to bend together with the tubes  11  when the displaceable baffles are displaced to the loaded portion. On the other hand, the holes in the fixed baffles for the tie rods may be made slightly larger so that bending of the tie rods can be reduced during the displacement of the displaceable baffles. The notches  33  are sized to receive the skid bar  6  therein. The skid bar  6  is provided to ensure support during insertion of the tube bundle  10  into the shell  20 . The notches  32  and  33  ensure that the displaceable baffles  300 , the fixed baffles  30  and  40  and the blocking baffles  60  (described below) are maintained in the proper orientation. The tie bars  5 , the skid bars  6  and the baffles  300 ,  30 ,  40  and  60  together form a rigid cage, which facilitates the insertion of the tubes  11  of the bundle  10 . The baffle  30  includes at least one partition lane blocking area  35  to redirect the flow of fluid within the shell of the heat exchanger  1  towards the tubes  11  of the tube bundle  10 . The slots  36  are arranged to correspond to the rows of the tubes  11  in the bundle  10 . A plurality of vertically extending ribs  37  are provided on the baffle  30 . Each rib  37  extends vertically between the slots  36 . Each rib  37  preferably has a thickness that is slightly smaller than the spacing between adjacent tubes  11  in the tube bundle  10 . 
     A fixed baffle  40  having horizontal slots  46  that provide support for the tubes  11  in the bundle  10  to reduce vibration is illustrated in  FIG. 14 . Like baffle  30 , the baffle  40  is configured to redirect the flow of fluid away from the gap between the outer tubes  11  of the tube bundle  10  and the inner surface of the shell  20  inwardly towards the tubes  11  in the bundle  10  away from the shell  20  and outwardly away from the partition lanes towards the tubes  11 . The baffle  40  has a blocking area  44 . The blocking area  44  has a similar construction or the blocking area  34 . The baffle  40  may also include at least one partition lane blocking area  45 . The baffle  40  includes a plurality of horizontal slots  46 . The slots  46  are located on opposing sides of the partition lane blocking area  35 . The slots  46  are sized to receive and support the tubes  11  of the tube bundle  10 . A plurality of horizontally extending ribs  47  are provided on the baffle  40 . Each rib  47  extends between the slots  46 . 
     When the displaceable baffles  300 ,  400  and the fixed battles  30 ,  40  contain slots for receiving the tubes therethrough, a blocking baffle  60  may be utilized as is illustrated in  FIG. 15 . The blocking baffle  60  is configured to direct the now of fluid inwardly towards the tubes  11  in the bundle  10  away from the shell  20  and outwardly away from the partition lane of the bundle. Each baffle  60  includes a blocking area  64  and a partition lane blocking area  65 . The blocking baffle  60  does not provide support to the tubes  11  in the bundle  10 . 
     The assembly of the tube bundle device  1  will now be described in greater detail. A rigid cage for the tube bundle  10  is constructed using the tie bars  5 , skid bars  6 , displaceable baffles  300  and  400  and the baffles  30 ,  40 , and  60 . The rigid cage is formed by securing the tie bars  5  and skid bars  6  within the respective slots  32  and  33  in the baffles  30 ,  40 , and  60 . The tie bars  5  and the skid bars  6  are preferably secured within the slots  32  and  33  by welding or other suitable attachment mechanism. The displaceable baffles  300  and  400  should not be welded to the tie bars and skid bars until after the two portions are displaced and secured in the final position. The displaceable baffles  300  and  400  and the fixed baffles  30  and  40  are spaced at a desired spacing. The baffles may have an alternating pattern with fixed baffles be located adjacent displaceable baffles. Vertically displaceable baffles are preferably located adjacent horizontally displaceable baffles. At least one blocking baffle  60  may be located between the baffles, as shown in  FIG. 1 . 
     Once the rigid cage has been assembled, the tubes  11  of the tube bundle  10  may be inserted into the cage. The tubes  11  are loaded into the bundle  10  by inserting the tubes  11  through the openings in the baffles. After the tubes  11  are located within the cage, the portions of the displaceable baffles are moved into the installed position, as described above. The portions are then secured in the installed position. The tubesheets  13  and  14  may be secured to the ends of the bundle  10 . This is accomplished by welding or otherwise securing the end of each tube  11  to a tubesheet. As discussed above, at least one of the tubesheets is stationary. It is contemplated that the ends of the tubes can be secured to a pair of tubesheets  13 , one stationary tubesheet  13  and one floating tubesheet  14  or one stationary tubesheet  13  when the U-tubes are used such that both ends of the tubes are secured to the same tubesheet  13 . The assembled tube bundle  10  is inserted into the shell  20  by sliding the bundle  10  along skid bars  6  into the shell. Once the bundle  10  is properly oriented within the shell  20 , the tubes sheets  13  are secured to the shell  20 . 
     It will be apparent to those skilled in the art that various modifications and/or variations may be made without departing from the scope of the present invention. Thus, it is intended that the present invention covers the modifications and variations of the apparatus and methods herein provided they come within the scope of the appended claims and their equivalents.