Abstract:
An apparatus and a method to remove and install heat exchanger bundles. The apparatus comprises a main frame supporting wheel assemblies. A second frame is vertically displaceable relative to the main frame. A lifting system is provided which elevates the entire unit so that the wheel assemblies are off the ground a minimal distance to ensure stability and then the second frame is elevated the remaining amount to the final elevation of the heat exchanger bundle to be removed or installed. The preferred embodiment includes a horizontally displaceable portion of the second frame for supporting the heat exchanger as it is extracted from the shell side assembly. The unit is self-contained including power means to horizontally displace the frame to affect the displacement of the heat exchanger, lower the second frame relative to the main frame, and then lower the entire unit to the ground. The unit is also powered so that the wheel assemblies which are individually steerable can maneuver the unit into a restricted area.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a Continuation-In-Part of U.S. patent application Ser. No. 09/866,276, filed May 25, 2001, which is a Continuation-In-Part of U.S. patent application Ser. No. 09/851,354, filed on May 8, 2001, which claims the benefit of U.S. Provisional Application Serial No. 60/235,131, filed on Sep. 25, 2000. 
     
    
     
       TECHNICAL FIELD  
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to a lifting and moving device. More particularly, the present invention relates to an improved apparatus and a method for removing and installing horizontally disposed heat exchanger bundles.  
           [0003]    Heat exchangers are used in chemical processing plants, such as petroleum refineries and distilling facilities for absorbing heat created by high temperature reactions. These heat exchangers utilize long metal tubes arranged in a cylindrical bundle. The bundle is generally heavy and may vary in diameter and length. For example, often these bundles may average one to six feet in diameter, twelve to twenty-four feet long and may have a weight of two to forty tons. Further, the preceding diameter, length, and weight may be exceeded.  
           [0004]    An individual bundle is typically inserted into a horizontally disposed shell and coupled to an inlet and an outlet in the heat exchanger system which typically has multiple bundles. To facilitate heat exchange, fluid enters into a bundle from its inlet in the heat exchanger thereby flowing through the individual tubes of the bundle and exits via the outlet. Heat exchanger fluid flows through the shell, past the outside of the tubes and the tube and shell fluids may travel through a series of horizontally stacked bundles before being collected for reuse or recycling. During use, the individual tubes of the bundle are subject to fouling and corrosion and also have a limited life. Thus, each bundle in the heat exchanger requires regular maintenance of the individual tubes of the bundle and eventual replacement thereof.  
           [0005]    The physical size and weight of the bundles create significant obstacles for maintenance and replacement. For maintenance, the bundle must be removed from its shell by a bundle extractor and often transported to another on-site location or an off-site facility more suited to the work required. A large heat exchanger may have multiple bundles arranged in stacks, one above the other. Thus, the lowest bundle may be contained in a shell a few feet off of the ground while the highest may be over thirty feet above the ground.  
           [0006]    Another obstacle is the need to support and balance the bundle as the bundle is pulled from its shell. This problem is compounded by the fact that these bundles vary in length. Thus, a method and apparatus are needed for removing these heat exchanger bundles at a wide variety of heights from ground level while keeping the bundles securely supported as they are pulled from their shells.  
           [0007]    A heat exchanger bundle is typically removed from its shell by a pulling car or sled of the extractor that exerts a pulling force on a tube sheet which is fixed to the ends of the tube bundle. Significant force is often required to break the bundle free from its shell due to normal product corrosion between the bundle and tube sheet and the shell. A pulling mechanism such as a winch, hydraulic jack, or screw drive and motors are typically used with the extractor pulling sled to break the bundle free. Once free, the bundle is positioned on a sliding carriage mounted on a frame of the extractor such that the bundle carriage is moved along the frame as the bundle is pulled from its shell. Due to the weight and length of the bundle, the carriage and frame may be tilted to balance the bundle as the bundle is removed.  
           [0008]    Different types of equipment have been used to support the carriage and frame of the extractors in their operative position for pulling of heat exchanger tubes bundles. U.S. Pat. Nos. 3,836,015 and 4,053,062 to Travis and U.S. Pat. Nos. 4,869,638 and 5,032,054 to Krajicek et al. disclose an aerial supported carriage and frame for being lifted by a crane and which may be moved off site using the crane or a helicopter. Another approach is mounting the frame to a telescoping column on a truck bed as disclosed in U.S. Pat. No. 4,575,305 to Krajicek et al. and U.S. Pat. No. 5,403,145 to Cradeur et al. Another extractor disclosed in U.S. Pat. No. 5,373,271 to Amuny uses four telescoping cylinders to support and lift the frame. U.S. Pat. No. 5,562,400 to Travis and U.S. Pat. No. 5,564,179 to Amuny disclose extractors that utilize wheels and drive means to provide a self-propelled bundle extractor and have outrigger lifting columns which raise the frame to the height of the bundle shell.  
           [0009]    Extractors which require the use of cranes to position the frame at the shell of the heat exchanger bundle are not practical for use in areas with limited clearance between the heat exchanger unit and other structures. Similarly, extractors mounted on truck beds present the same space concerns. In these limited clearance areas, there may not be adequate space to position a crane or truck between the structures. Thus, a mobile extractor that is self-propelled and has a self-contained mechanism for raising and lowering its extractor frame is usually preferred due to the limited clearances between structures.  
           [0010]    U.S. Pat. Nos. 5,562,400 and 5,564,179 disclose self-propelled extractors a support frame and carriage that are mounted on wheels with hydraulic cylinders or telescoping lifting columns. The extractor of the latter patent utilizes the lifting columns to raise both the support frame and carriage to the vertical position of the heat exchanger shell; whereas, U.S. Pat. No. 5,562,400 uses the lifting columns to raise only a carriage frame having a pulling sled and skids. Due to the extreme weight of the heat exchanger bundle, which can exceed forty tons, the use of rubber wheels is not practical because they cannot support the weight. However, rubber wheels can accommodate lighter bundle loads of about twenty five tons or less, for example, Therefore, steel wheels with polyurethane shells can be used for the heavier bundle loads which may be too heavy for rubber wheels.  
           [0011]    One problem with self-propelled extractors of this type is that the heat exchanger units are typically located outside on asphalt or gravel surfaces which may become soft due to rain or sun exposure such that the steel wheels often dig into the surface as the extractor is moved across the surface or when turning. After the bundle is pulled onto the extractor, the added weight often embeds the wheels into the surface making it impossible for the extractor to move under its own power. As an alternative, a self-propelled extractor may provide for lifting the extractor with a crane such as that disclosed in U.S. Pat. No. 5,564,179. Due to the weight of the extractor and bundle, which may be over sixty-five tons, a large crane is required. Under some union rules, the operation of a large crane requires two workers, an operator and an oiler. However, for the operation of smaller cranes, only one worker is required, the operator. To support two shifts of extractor operations, the added oiler increases the labor costs approximately $6,000 to $8,000 per shift per week.  
           [0012]    Another problem with known extractors is that the telescoping columns which lift the support frame and carriage of the extractor to the height of the shell become very unstable when the support frame is near or at the top of its vertical travel due to the progressive upwardly shifting of the extractor&#39;s center of gravity. The four telescoping columns usually have to support the entire weight of the support frame carriage and eventually the bundle, e.g. see U.S. Pat. No. 5,564,179. Furthermore, as the bundle is being pulled onto the carriage, the added weight of the bundle to the front of the extractor adjacent the shell shifts the center of mass of the extractor, rendering it unstable. Likewise, as the bundle is being pulled from the shell and onto the carriage, the changing position of its center of mass may tilt the extractor frame such that one of the front or the rear columns may support more weight than the others, which may cause the extractor to tilt or rock. Thus, added precautions must be taken to prevent or compensate for the sudden shifts in weight to prevent the extractor from overturning.  
           [0013]    Accordingly, a method and apparatus are needed that provide a heat exchanger bundle extractor apparatus that remains stable when removing or installing heat exchanger bundles at high levels above ground surface. Further, a method and apparatus which can fit into tight spaces for accessing bundles, while still having stability during a pulling operation with the ability to transport a pulled bundle to another location thereafter, is needed.  
           [0014]    Furthermore, a method and apparatus are needed that provide an improved heat exchanger bundle extractor apparatus that can maneuver around the plant or facility at relatively higher speeds to accommodate time constraints, yet at the same time continue to provide the flexibility discussed above.  
         SUMMARY OF THE INVENTION  
         [0015]    In accordance with the present invention, at least four wheel assemblies and main frame having a carriage frame with four vertical hydraulic cylinders may be used and may achieve the stability necessary to support and level a heat exchanger bundle during removal from its shell at various vertical heights and to move the extractor, with or without a bundle, across gravel, asphalt and uneven surfaces. Preferably, at least two of the wheel assemblies are individually powered and all four are individually steerable. The wheel assemblies are at least attached to a main frame and may be used to support and provide movement to the extractor. An engine, preferably an air cooled diesel engine, may be used to drive individual hydraulic motors which power and steer the wheel assemblies and may allow the extractor to be driven to and from the in-use location of the heat exchanger bundles. Each tire of each wheel assembly provides a large enough surface area to spread the load of the extractor and the bundle on the ground. Accordingly, the large constant surface area will prevent the unit from becoming embedded into the ground The wheel assemblies also provide a design which can accommodate speeds of up to 10 to 12 mphs.  
           [0016]    Preferably, a first set of four hydraulic cylinders may be vertically mounted at the corners of a rectangular main frame of the extractor. The base of each cylinder may have a pad for engaging the ground and may have a spherical joint. When the extractor is stationary for removing a bundle, each pad may be positioned to match the grade of the ground to balance and support the extractor which may increase stability in its stationary position.  
           [0017]    A second set of the hydraulic cylinders may be attached to a carriage frame and to the main frame. Actuating the piston may raise and lower the carriage frame with respect to the main frame. Accordingly, each cylinder may be independently controlled to tilt and level the carriage frame to compensate for a grade in the surface and the changing center of gravity of the extractor during removal of the bundle from its shell and during the raising and lowering of the carriage frame.  
           [0018]    Alternatively, the extractor may be raised or moved using a crane or helicopter by removing the carriage frame from the main frame at disconnects located at the hydraulic cylinders and the main frame. Cylindrical horizontal shafts may be provided at each corner of the carriage frame for attaching slings to lift the carriage frame and bundle. Disconnecting the carriage frame from the main frame provides a lightweight, aerial extractor by eliminating the main frame, track, drive motor, and/or hydraulic cylinders.  
           [0019]    In the preferred configuration the main frame, including the wheel assemblies, are lifted off the ground during the extraction and re-insertion phases by the lower portions of the hydraulic cylinders. Thus, the main frame remains off but relatively near the ground for increase stability.  
           [0020]    In an embodiment, lifting members are provided having feet wherein the plurality of lifting members raise the frame.  
           [0021]    In an embodiment, power cylinders having feet are provided wherein the power cylinders raise the frame.  
           [0022]    In an embodiment, a pulling member is associated with the frame wherein the pulling member attaches to the heat exchanger bundle.  
           [0023]    In an embodiment, a base frame and an upper frame are provided wherein the base frame is larger than the upper frame and the base frame remains fixed as the upper frame vertically shifts.  
           [0024]    In an embodiment, a base frame portion and a smaller frame portion of the frame is provided wherein the smaller frame portion is detachable from the frame such that the heat exchanger bundle and the smaller frame portion may be lifted from the base frame portion.  
           [0025]    In an embodiment, a connection is provided between the base frame portion and the smaller frame portion.  
           [0026]    In an embodiment, the frame has a length substantially aligned with that of the heat exchanger bundle.  
           [0027]    In another embodiment of the present invention, a method is provided for supporting a load to be removed four an in-use location. The method comprises the steps of: providing an apparatus for removing the heavy load; providing a propelling mechanism on the apparatus; providing at least four wheel assemblies; aligning a vertically shiftable frame portion of the apparatus with the load; removing the load from the in-use location; shifting the load onto the frame portion; spreading the load over a predetermined area on a support surface adjacent to the in-use location; and stabilizing the apparatus as the load is shifted.  
           [0028]    In an embodiment, integrating the propelling mechanism provided with the apparatus such that the apparatus is self-propelled.  
           [0029]    In an embodiment, maneuvering the apparatus onto the support surface is provided.  
           [0030]    In an embodiment, a first frame portion and a second frame portion of the apparatus is provided wherein the first frame portion is aligned with the load to be removed and wherein the first frame portion has connections associated with the second frame portion.  
           [0031]    In an embodiment, connecting a lifting device to the connections on the first frame portion is provided.  
           [0032]    In an embodiment, disconnecting the first frame portion from the second frame portion is provided.  
           [0033]    In an embodiment, lifting the first frame portion and the load is provided.  
           [0034]    In an embodiment, the load is one of a plurality of heat exchanger bundles that are at various levels of elevation relative to the support surface.  
           [0035]    In an embodiment, pulling the load and progressively shifting the load onto the frame portion is provided.  
           [0036]    In another embodiment of the present invention, a method is provided for supporting and moving a heat exchanger bundle over a transport surface. The method comprises the steps of: providing a mobile extractor apparatus having a carriage frame and a main frame; providing a propelling mechanism for moving the apparatus along the transport surface; raising the carriage frame relative to the main frame to the height of the heat exchanger bundle wherein the main frame is elevated above, but remains relatively near the transport surface; pulling the heat exchanger bundle onto the carriage frame; lowering the carriage frame and the heat exchanger bundle toward the transport surface; powering and steering the main frame using the propelling mechanism; transporting the heat exchanger bundle; and supporting the heat exchanger bundle with the apparatus, the carriage frame, and the main frame while maintaining a surface area of engagement between the engaging surface and the transport surface.  
           [0037]    In another embodiment of the present invention, the method actuates hydraulic cylinders of the mobile extractor apparatus to raise the carriage frame.  
           [0038]    In another embodiment of the present invention, a method is provided for supporting and moving a heat exchanger bundle. The method comprises the steps of: providing a mobile extractor apparatus having a carriage frame, a main frame, and a propelling mechanism; moving the mobile extractor apparatus along the surface with the propelling mechanism; raising the main frame, raising the carriage frame relative to the main frame; lifting the carriage frame from the main frame to the height of the heat exchanger bundle while the main frame remains relatively near the surface; pulling the heat exchanger bundle onto the carriage frame; lowering the carriage frame and the heat exchanger bundle toward the transport surface; connecting a lifting device to the carriage frame; disconnecting the carriage frame from the main frame; and lifting the carriage frame and the heavy heat exchanger bundle supported by the carriage frame while the main frame and propelling mechanism remain in contact with the engaging surface.  
           [0039]    In an embodiment, the method actuates hydraulic cylinders of the mobile extractor apparatus to lift the carriage frame.  
           [0040]    Additional features and advantages of the present invention are described in, and will be apparent from, the detailed description of the presently preferred embodiments and from the figures. 
       
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0041]    [0041]FIG. 1 illustrates a perspective view of an embodiment of the apparatus for extracting and installing heat exchanger bundles.  
         [0042]    [0042]FIG. 2 illustrates a perspective view of another embodiment of the apparatus for extracting and installing heat exchanger bundles.  
         [0043]    [0043]FIG. 3 illustrates an elevation view of yet another embodiment of the apparatus for extracting and installing heat exchanger bundles.  
         [0044]    [0044]FIG. 4 illustrates a plan view looking up of the embodiment of the apparatus as shown in FIG. 3.  
         [0045]    [0045]FIG. 5 illustrates an elevation view of the ultimate embodiment of the apparatus shown in FIG. 3 in an operating mode with the wheel assemblies lifted off the ground and beginning the extraction of a heat exchanger.  
         [0046]    [0046]FIG. 6 is a perspective view of the sled assembly of the ultimate embodiment shown in FIG. 3.  
         [0047]    [0047]FIG. 7 is a detail view of the sled shown in FIG. 6.  
         [0048]    [0048]FIG. 8 is a partial elevation view of the embodiment of the invention shown in FIG. 3 in operational mode.  
         [0049]    [0049]FIG. 9 is also a partial elevation view of the invention shown in FIG. 3 in operational mode. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0050]    As shown in drawings for purposes of illustration, the invention is embodied in a heat exchanger tube bundle extractor apparatus  10 . As shown in FIG. 1, the extractor apparatus  10  is embodied in a rectangular main frame  12  having a long pair of parallel members  14  and shorter parallel cross members  16 . At each intersection of the long member  14  and the cross members  16  is a base cylinder  18  which may be attached thereto. Each base cylinder  18  may have a support pad  20  having approximately seventy-five square inches of surface area for engaging the ground. The support pad  20  may be attached to eight inner cylinders  22  which may be received by the base cylinder  18  such that the support pad may be lowered to the ground.  
         [0051]    One form of the extractor apparatus  10  may utilize a spherical joint (not shown) so that the angle in which support pad  20  may engage the ground may be adjusted to accommodate the grade of the ground at a location of each of the support pads  20 . Thus, each of the support pads  20  and the inner cylinder  22  may have a spherical joint so that each of the support pads  20  may be independently adjusted to increase stability of the extractor apparatus  10  when in a stationary position.  
         [0052]    The base cylinder  18  may also receive a piston  24  from a hydraulic cylinder  26 . The upper portion of the hydraulic cylinder  26  may be attached to a carriage frame  28 . The carriage frame  28  may also be rectangular; however, it is smaller than the main frame  12 . The carriage frame  28  may have two shorter cross members  30  at each end which may be detachably mounted to the hydraulic cylinders  26  by disconnects (not shown). When the piston  24  of the hydraulic cylinder  26  is actuated, the carriage frame  28  may be raised above main frame  12 . Each of the hydraulic cylinders  26  may be independently actuated to raise and tilt the carriage frame  28  to compensate for any grade in the support surface and the changing center of gravity due to the weight of the heat exchanger bundle (not shown) as the heat exchanger bundle is pulled onto the carriage frame  28  as described herein. Independent actuation of the hydraulic cylinders  26  may eliminate the need for leveling devices on the carriage frame  28 , thereby reducing weight and minimizing the number of moving parts requiring maintenance.  
         [0053]    When the hydraulic cylinders  26  are actuated, the pistons  24  may be driven downward which in turn may raise the carriage frame  28  above main frame  12  which may remain stationary. With the main frame  12  position close to the ground, the extractor apparatus  10  may maintain stable as the carriage frame  28  rises. In its lowest position above the main frame  12 , the carriage frame  28  may be used to remove heat exchanger bundles as low as forty-three inches off of the ground if a track assembly is used. When the hydraulic cylinders  26  are actuated to the their full length of the pistons  24 , the carriage frame  28  may be approximately fifteen feet above the ground.  
         [0054]    Mounted to each parallel long member  14  of the main frame  12  may be tracks  32  and  34 . The tracks  32  and  34  have plates  36  which may be made from polystyrene and may have a large smooth surface for engaging the ground. The smooth surface of the plates  36  as compared to those having ridges or tread, may maximize the surface area of the plate for supporting the weight of the extractor apparatus  10  and heat exchanger bundle (not shown).  
         [0055]    Alternatively, the smooth surface of the plates  36  may be replaced with a surface having tread for use on slippery terrain such as mud or loose gravel. The plates  36  may be approximately fourteen inches in width and may be positioned one after the other with a space between each of the plates  36 . The plates  36  may be joined by fastening devices to compose the continuous eight foot tracks  32  and  34 .  
         [0056]    The tracks  32  and  34  may be supported by a frame (not shown) with a drive member (not shown) to rotate the tracks  32  and  34  about the frame which, in turn, provides translation of the extractor apparatus  10 . The tracks  32  and  34  and frame configuration may provide a predetermined, large area of approximately sixteen square feet in contact with the ground at all times. An engine (not shown) may provide the power to rotate the tracks  32  and  34  about the frame. As known in the art of track driven equipment, the tracks  32  and  34  are independently driven such that the extractor apparatus  10  may be turned by holding one track stationary while rotating the opposite track, which causes the extractor apparatus  10  to rotate in the direction of the track being held.  
         [0057]    On the carriage frame  28  may be a series of sliding cross members  38  which may allow for adjusting the width of carriage frame  28  to accommodate the heat extractor bundles of varying width. The width of the carriage frame  28  may be adjusted for a particular diameter of the heat extractor bundle before or after transporting the heat exchanger bundle and the extractor apparatus  10  to the shell.  
         [0058]    The extractor apparatus  10  may be transported to the work location by an engine that may provide power to the tracks  32  and  34 . The support pads  20  may be lowered to the ground by extending the inner cylinder  22  downwards from the base cylinder  18  such that the support pad  20  is firmly planted on the ground. The support pads  20  may have a diameter of approximately seventy-five square inches and may be twice as great as that of the inner cylinder  22 .  
         [0059]    Each of the base cylinders  18  may have independent movement to accommodate uneven surfaces. After the support pads  20  are firmly planted, the hydraulic cylinders  26  may be used to raise the carriage frame  28  to the height of the shell where the heat exchanger bundle is located. The carriage frame  28  may rise as the piston  24  of each of the hydraulic cylinders  26  is actuated. The system of the hydraulic cylinders  26  and the pistons  24  may allow the main frame  12  to remain low to the ground to provide stability and a low center of gravity. Furthermore, each of the hydraulic cylinders  26  may be independently actuated, to compensate for uneven surfaces by leveling the carriage frame  28 .  
         [0060]    After the carriage frame  28  is at the proper height location at the shell, the width of the carriage frame  28  may be adjusted using the sliding cross members  38  to accommodate the diameter of the heat exchanger bundle. A sled (not shown) that is mounted to carriage frame  28  may be used to attach the heat exchanger bundle to the extractor apparatus  10 . A chain or wire cable may be used to secure the heat exchanger to the sled (not shown). The sled may also utilize a small motor (not shown) on the main frame  12  to move the sled that in turn may pull the attached heat exchanger bundle on to the carriage frame  28 . As the weight of the heat exchanger bundle shifts on the carriage frame  28 , the hydraulic cylinders  26  may be adjusted to keep the heat exchanger bundle level or parallel with the ground and to keep the apparatus stable and prevent tipping of the apparatus.  
         [0061]    When the heat exchanger bundle is completely removed from the shell, the extractor apparatus  10  may be used to transport the heat exchanger bundle to a remote location for further inspection and maintenance work. The tracks  32  and  34  may be used to move the extractor apparatus  10  with the heat exchanger tube bundle carried on the carriage frame  28 . This method of movement may be used to transport the heat exchanger tube bundle to the remote location, or in the alternative, the carriage frame  28  may be removed from the main frame  12  at the base cylinders  18  or alternatively at the hydraulic cylinders  26 . Cables or chains (not shown) may be attached to hooks  40  to provide a means for lifting the carriage frame  28  and the heat exchanger bundle from the main frame  12  and thereby leaving the tracks  32  and  34  on the ground along with the engine. This provides a lighter weight system that may be aerially removed using a crane or helicopter. Furthermore, the carriage frame  28  and heat exchanger bundle may be aerially removed and loaded on a flatbed truck or railcar for transportation offsite.  
         [0062]    Referring now to FIG. 2, in another embodiment of the present invention, another extractor apparatus  50  is illustrated. As shown in FIG. 2, the extractor apparatus  50  is embodied in a rectangular main frame  52  having a long pair of parallel members  54  and shorter parallel cross members  56 . At each intersection of the long member  54  and the cross members  56  is a siamese cylinder  58  which may be attached thereto. Each siamese cylinder  58  may have a support pad  60  having approximately seventy-five square inches of surface area for engaging the ground. The support pad  60  may be attached to eight inner cylinders (not shown) which may be received by the siamese cylinder  58  such that the support pad  60  may be lowered to the ground.  
         [0063]    One form of the extractor apparatus  50  may utilize a spherical joint (not shown) so that the angle in which the support pad  60  may engage the ground may be adjusted to accommodate the grade of the ground at a location of each of the support pads  60 . Thus, each of the support pads  60  and the inner cylinders (not shown) may have a spherical joint so that each of the support pads  60  may be independently adjusted to increase stability of the extractor apparatus  50  when in a stationary position.  
         [0064]    The siamese cylinder  58  may also receive a piston  64  from a hydraulic cylinder  66 . The upper portion of the hydraulic cylinder  66  may be attached to a carriage frame  68 . The carriage frame  68  may also be rectangular. The carriage frame  68  may have two shorter cross members  70  at each end which may be detachably mounted to the hydraulic cylinders  66  by disconnects (not shown). When the piston  64  of the hydraulic cylinder  66  is actuated, the carriage frame  68  may be raised above main frame  52 . Each of the hydraulic cylinders  66  may be independently actuated to raise and/or tilt the carriage frame  68  to compensate for any grade in the support surface and the changing center of gravity. The center of gravity may change due to the weight of the heat exchanger bundle (not shown) as the heat exchanger bundle is pulled onto the carriage frame  68  as described herein. Independent actuation of the hydraulic cylinders  66  may eliminate the need for leveling devices on the carriage frame  68 , thereby reducing weight and/or minimizing the number of moving parts requiring maintenance.  
         [0065]    When the hydraulic cylinders  66  are actuated, the pistons  64  may be driven downward which in turn may raise the carriage frame  68  above the main frame  52  which may remain stationary. With the position of the main frame  52  close to the ground, the extractor apparatus  50  may maintain stable as the carriage frame  68  rises. In the range from the lowest position and the highest position of the carriage frame  68  above the main frame  52 , the carriage frame  68  may be used to remove heat exchanger bundles. The carriage frame  68  may be positioned as low as forty-three inches off of the ground when using a track assembly. When the hydraulic cylinders  66  are actuated to the their full length of the pistons  64 , the carriage frame  68  may be positioned approximately fifteen feet above the ground.  
         [0066]    Mounted to each parallel long member  54  of the main frame  52  may be tracks  72  and  74 . The tracks  72  and  74  have plates  76  which may be made from polystyrene and may have a large smooth surface for engaging the ground. The smooth surface of the plates  76  as compared to those having ridges or tread, may maximize the surface area of the plate for supporting the weight of the extractor apparatus  50  and heat exchanger bundle (not shown).  
         [0067]    Alternatively, the smooth surface of the plates  76  may be replaced with a surface having tread for use on slippery terrain, such as mud or loose gravel. The plates  76  may be any length, however, preferably, the plates are approximately fourteen inches in width and may be positioned one after the other with a space between each of the plates  76 . The plates  76  may be joined by fastening devices (not shown) to compose the continuous eight foot tracks  72  and  74 .  
         [0068]    The tracks  72  and  74  may be supported by a frame  62  with a drive member (not shown) to rotate the tracks  72  and  74  about the frame which, in turn, provides translation of the extractor apparatus  50 . The tracks  72  and  74  and the configuration of the frame  62  may provide a predetermined, large area in contact with the ground at all times. Preferably, predetermined large area of the track may be approximately sixteen square feet. An engine  78  may provide the power to rotate the tracks  72  and  74  about the frame  62 . As known in the art of track driven equipment, the tracks  72  and  74  may be independently driven such that the extractor apparatus  50  may be turned by holding one track stationary while rotating the opposite track, which causes the extractor apparatus  50  to rotate in the direction of the track being held.  
         [0069]    On the carriage frame  68  may be a series of sliding cross members (not shown) which may allow for adjusting the width of carriage frame  68  to accommodate the heat extractor bundles of varying width. The width of the carriage frame  68  may be adjusted for a particular diameter of the heat extractor bundle before or after transporting the heat exchanger bundle and the extractor apparatus  50  to the shell.  
         [0070]    The extractor apparatus  50  is transported to the work location by the engine  78  that may provide power to the tracks  72  and  74 . After the extractor apparatus  50  is at the proper location, the support pads  60  may be lowered to the ground by extending the inner cylinders downwards from the siamese cylinder  58  such that the support pads  60  may be firmly planted on the ground. The support pads  60  may have a diameter of approximately seventy-five square inches and may be twice as great as that of the inner cylinders.  
         [0071]    Each siamese cylinder  58  may have independent movement to accommodate uneven surfaces. After the support pads  60  are firmly planted, the hydraulic cylinders  66  may be used to raise the carriage frame  68  to the height of the shell where the heat exchanger bundle is located. The carriage frame  68  may rise as the piston  64  of each of the hydraulic cylinders  66  is actuated. The system of the hydraulic cylinders  66  and the pistons  64  may allow the main frame  52  to remain low to the ground to provide stability and a low center of gravity. Furthermore, each of the hydraulic cylinders  66  may be independently actuated to compensate for uneven surfaces by leveling the carriage frame  68 .  
         [0072]    After the carriage frame  68  is at the proper height location at the shell, the width of the carriage frame  68  may be adjusted, and a grabber  80  that may be mounted to carriage frame  68  may be used to attach the heat exchanger bundle (not shown) to the extractor apparatus  50 . A chain or wire cable (not shown) may be used to secure the heat exchanger to the grabber  80  and to cylinders  86 . A grabber cylinder  88  on each of beams  90  of the carriage frame  68  may move the grabber  80  a distance out relative to the carriage frame  68 .  
         [0073]    The carriage frame  68  may have a plate  84 . A motor  82  on the carriage frame  68  may rotate a pump (not shown) that may power a hydraulic motor (not shown) which may power a hydraulic brake (not shown) that may power an actuator (not shown) that, in turn, may rotate a screw  92 . The screw  92  may be attached at to the plate  84  at one end and to a trough  94  at another end. The trough  94  holds a sled  96 . The sled  96  may be moved forward or back by the screw  92 . The sled  96  moves within the trough  94 . The trough  94  may be housed within the beams  90 . Beam cylinders  98  may move the beams  90  forward and back relative to the carriage frame  68 . Thus, the carriage frame  68  preferably has three sections that may move relative to the carriage frame: the grabber  80 , the beams  90  and the sled  96 . The grabber  80  and the beams  90  may extend the length of the carriage frame  68 .  
         [0074]    After the carriage frame  68  is in place, the chain or wire cable may be used to secure the heat exchanger to the grabber  80  and to cylinders  86 . The grabber  80  may then be pulled back by the grabber cylinder  88  on each of the beams  90 . The grabber  80  and the cylinders  86  may break the heat exchanger bundles out of their shell and pull the heat exchanger bundles onto the sled  96  of the carriage frame  68 . The sled  96  and the beams  90  may retract to pull the heat exchanger bundle fully onto the carriage frame  68 .  
         [0075]    As the weight of the heat exchanger bundle shifts on the carriage frame  68 , the hydraulic cylinders  66  may be adjusted to keep the heat exchanger bundle level or parallel with the ground and to keep the extractor apparatus  50  stable and prevent tipping of the extractor apparatus  50 .  
         [0076]    When the heat exchanger bundle is completely removed from the shell, the extractor apparatus  50  may be used to transport the heat exchanger bundle to a remote location for further inspection and maintenance work. The tracks  72  and  74  may be used to move the extractor apparatus  50  with the heat exchanger tube bundle carried on the carriage frame  68 . This method of movement may be used to transport the heat exchanger bundle to the remote location, or in the alternative, the carriage frame  68  may be removed from the main frame  52  at the siamese cylinders  58  or alternatively at the hydraulic cylinders  66 .  
         [0077]    Cables or chains (not shown) may be attached to the carriage frame  68  to provide a means for lifting the carriage frame  68  and the heat exchanger bundle from the main frame  52  and thereby leaving the tracks  72  and  74  on the ground along with the engine  78 . Removing the carriage frame  68  from the main frame  52  provides a lighter weight system that may be aerially removed using a crane or helicopter. Furthermore, the carriage frame  68  and the heat exchanger bundle may be aerially removed and loaded on a flatbed truck or railcar for transportation offsite.  
         [0078]    Alternatively, the carriage frame  68  may be removed from the main frame  52  and aerially transported without the main frame  52  and engine  78  to the work location before extracting the heat exchanger bundles. After the carriage frame  68  is transported to the work location and is at the proper height location at the shell, the sled  80  that is mounted to the carriage frame  68  may be used to attach the heat exchanger bundle to the carriage frame  68 . The small motor  82  may move the sled  80  that, in turn, may pull the attached heat exchanger bundle onto the carriage frame  68 .  
         [0079]    Referring now to FIGS.  3 - 7 , an alternate embodiment of the present invention is shown. The reference numerals in these figures are in the 100 series and generally the last two digits of these numbers correspond with the similar element of the embodiment shown in FIG. 2 and discussed in association with FIG. 2.  
         [0080]    Referring to FIGS.  3 - 5 , extractor apparatus  150  is illustrated which includes a rectangular main frame  152  comprised generally of longitudinal parallel members  154  and shorter transverse members  156 . At the corner intersections of members  154  and cross-members  156  are located four siamese cylinder assemblies  158 . Each siamese cylinder assembly  158  includes a first cylinder assembly  159  and a second cylinder assembly  161 . Cylinder assembly  159  is preferably a hydraulic cylinder having an internal piston  163  attached to a support pad  160 . Referring to FIG. 5, second assembly  161  includes telescoping pistons  165 .  
         [0081]    Extractor apparatus  150  also includes a carriage frame  168  which is composed of longitudinal numbers  169  and transverse cross-members such as members  70  in FIG. 2.  
         [0082]    As shown in FIG. 5, the outer housing portion of cylinder assembly  161  is mounted to longitudinal members  169  of carriage frame  168  while the end of telescoping member  165  is mounted to main frame  154 . In this manner, hydraulic activation of first cylinder assembly  159  will extend piston rods  163  until support pads  160  contact the ground surface, thereby elevating both main frame  152  and everything associated with main frame  152 , such as carriage frame  168 .  
         [0083]    Referring to FIG. 3 the extractor apparatus  150  also includes four wheel assemblies  172 . One of the principal differences in this embodiment from the embodiment shown in FIGS. 1 and 2 is the substitution of four wheel assemblies  172  for the tracks  32  and  34  of FIG. 1 and  72  and  74  of FIG. 2. Referring to FIG. 4, each wheel assembly  172  is pivotally attached to a longitudinal frame  154  by a pivot plate  173  attached to member  154  at pivot point  175 . Each wheel assembly  172  is therefor pivotable relative to member  154  by extending or contracting hydraulic cylinder  177 . In this manner, steering motion is provided to each wheel assembly. Also, each wheel is individually steerable which permits the operator to locate the extractor apparatus  150  proximate the shell assembly  300 .  
         [0084]    Additionally, at least two of the four wheel assemblies are powered by a hydraulic direct drive wheel motor mounted within the wheel. Such hydraulic motors are commonly known to those skilled in the art. See, for example, Model MS-18 which may be purchased from the French company Poclain Hydraulics. These hydraulic motors provide the power necessary to advance the extractor apparatus  150  in a forward or reverse mode. The hydraulic motors may be driven, for example, by engine  178 , which is a diesel engine used to generate hydraulic pressure necessary to drive the motors. Similarly, extractor apparatus  150  would include a control system commonly known to those skilled in the art to control the operation of each hydraulic drive motor to advance it forward and rearward and to control the steering of each wheel assembly.  
         [0085]    Other than the substitution of wheel assemblies  172  for tracks  32 / 36  and  72 / 74  of the earlier embodiments, the operation of the extractor assembly  150  is identical to that illustrated in FIGS. 1 and 2 and discussed earlier. For example, extractor apparatus  150  includes not only a main frame  152  and a carriage frame  156  with corresponding parts as discussed above, but it would also include a motor  182  which is mounted on the carriage frame to rotate a pump that in turn would rotate a screw such as screw  92  as shown in FIG. 2. As before, screw  92  which may be located in the extractor apparatus  150  would be housed within a trough  94  as shown in FIG. 2 and discussed above. A sled  96  may be moved forward and backward by the screw  92  as discussed above. However, in the extractor apparatus  150 , the sled  196  would preferably be used as described and shown more fully in FIGS. 6 and 7.  
         [0086]    Referring now to FIGS. 6 and 7, sled  196  is composed of a base portion  200 , which slides within a trough  194  which is similar in structure to that shown and described as trough  94  in FIG. 2. Base portion  200  supports two moving sections: vertical transfer section  202  and horizontal transfer section  204 . As shown in FIG. 7, section  204  is supported on section  202  and is capable of moving transversely with respect to sections  202  along lip portion  205  which slides within grooves  206  of portion  204 . Preferably, Teflon pads would be located on these contact surfaces to facilitate a smooth movement of portion  204  relative to  202 . Similarly, vertical portion  202  is supported within base portion  200 . Again, plate  208  of portion  202  includes end surfaces  210  which slide within channel  212  of base portion  200 . In this manner, vertical movement of portion  202  will also result in vertical movement of portion  204 . Portion  204  also includes a vertical member  220  and horizontal members  222 . A lip  224  is attached at the end of members  222 . In this manner, vertical and horizontal movement of portions  202  and  204  will permit the operator to move plates  222  and  224  relative to the precise end position of the heat exchanger within the shell assembly thereby enabling the operator to grab the end of the heat exchanger and remove it from the shell assembly as discussed in more detail below.  
         [0087]    Horizontal movement of portion  204  relative to vertical portion  202  is achieved by double actuating hydraulic cylinder  230 . As a double acting cylinder, single movement of this cylinder will enable easy relative movement of portion  204  relative to portion  202 . Similarly, vertical movement of piece  202  is provided through the use of a hydraulic cylinder (not shown) which moves piece  202  (and therefore piece  204 ) relative to base portion  200 .  
         [0088]    As noted above with respect to the embodiment shown in FIG. 2, the embodiment shown in FIGS.  3 - 5  would also include beam cylinders  98  which move beam  90  forward and back relative to the carriage frame  168 . Thus, the carriage frame  168  preferably has three sections that may move relative to the carriage frame: gripper bars  180 , beams  90  and sled  196 . The gripper bars  180  and the beams  90  (shown as FIG. 2) may extend the length of the carriage frame  168 .  
         [0089]    Referring now to FIGS. 8 and 9, and in particular first FIG. 8, the grabber  180  is extended to buttress against shell assembly  300 . This is accomplished by cylinders  186  (see also FIG. 2). At that point, a sling  187  as shown in FIG. 8 may be attached through a threaded eyebolt  189  to the heat exchanger  191  and looped over one of the pins  193  of sled  196 . In this manner, the slack in sling  187  can be taken up by activation of cylinder  88  (see FIG. 2) which pushes grabber  180  against shell  300 . The heat exchanger  191  is thus broken out of the shell. The sled  196  may then be retracted by rotation of the screw  92  (see FIG. 2) a sufficient distant to enable the sled  196  to advance forward under the lip  195  of heat exchanger  191  as shown in FIG. 9.  
         [0090]    As noted above, it may not be possible to precisely position the plates  222  and lip  224  of sled  196  immediately below flange  195  of exchanger  191 . If the alignment is not correct, the operator may activate the vertical cylinders of sled  196  thereby moving pieces  202  and  204  relative to base portion  200  as well as the double acting cylinder  230  which moves portion  204  horizontally relative to portion  202 . In this manner, the operator may precisely position the plates  222  and the lip  224  of sled  196  immediately below the flange  195  as shown in FIG. 9. At that point, the sling  187  can be removed and the rotating screw  92  (see FIG. 2) can then be activated to advance sled  196  to the left as shown in FIG. 9 extracting the heat exchanger  191  from shell  300 .  
         [0091]    As noted above with respect to FIG. 2, this extraction will continue until the heat exchanger bundle is fully supported by the carriage frame  168 . As the weight of the heat exchange bundle shifts onto the carriage frame  68 , the hydraulic cylinder  66  (see FIG. 2) can be adjusted to keep the heat exchanger bundle level and parallel with the ground and to keep the extractor apparatus  150  stable and prevent tipping or excessive movement.  
         [0092]    When the heat exchanger bundle is completely removed from the shell  300 , the extractor apparatus  150  may be used to transport the heat exchanger bundle to a remote location for further inspection and maintenance. That is, cylinder assemblies  161  are activated lowering the carriage frame  168  onto main frame  152 . At that point, cylinder assemblies  159  are activated lowering wheel assemblies  172  to the ground. In this embodiment, it is anticipated that the wheels would be lifted a maximum of approximately 2 to 3 feet off the ground and that the unit itself is capable of lifting extractors up to about 25 to 30 tons at a height of approximately 20-25 feet.  
         [0093]    As noted above with respect to the embodiments shown in FIGS. 1 and 2, the carriage frame  168  may be removed from the main frame  152  and aerially transported without the main frame  152  and wheel assemblies  172 . In this manner, the carriage frame  168  may be transported to a work location that is at a location higher than would otherwise be accommodated by extractor apparatus  150 .  
         [0094]    Unless otherwise indicated herein with respect to extractor apparatus  150 , the operation of extractor  150  is identical to that of the extractor apparatus  10  and  50  as shown and discussed with respect to FIGS. 1 and 2, respectfully.  
         [0095]    It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is, therefore, intended that such changes and modifications be covered by the appended claims.