Abstract:
A flange bolt cutter for separating two connected flanges. The flange bolt cutter contains a circular saw blade pivotally connected to an adjustable flange band. The flange band contains an alignment ring for aligning the circular saw blade about the midpoint between two connected flanges. The flange bolt cutter is hydraulically operated. The adjustable flange band may be formed in two band sections hinged together and containing a rotatable bolt and handle for tightening and loosening the band sections around the flange connection.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Provisional Patent Application No. 61/249,243, filed on 6 Oct. 2009, which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to an apparatus for cutting bolts, and more particularly, an apparatus for cutting flange bolts. 
     BACKGROUND OF THE INVENTION 
     Oil and natural gas platforms and installations have a limited life of operations. When oil runs out, the platforms and installations are decommissioned using a number of different alternatives. As examples, the platforms and installations may be (a) left completely or partially in the water (often called “reefing”); (b) removed and then reused in another location; or (c) hauled to shore for scrapping or recycling. 
     The majority of platform decommissioning in the world has occurred in the Gulf of Mexico. The process of decommissioning typically begins with well abandonment in which the well bores are filled with cement. The vertical pipes that carry the oil and gas are then removed. In the past, use of explosives was the most commonly used method for removing the vertical pipes. However, the use of explosives has become controversial because explosions, particularly underwater explosions, generate intense shock waves that cause instantaneous lethal impacts for marine life residing on or near the platform structure. As a result, non-explosive methods have become the preferred method of removing vertical pipes. 
     One of the problems encountered while using non-explosive methods to remove vertical pipes during decommissioning is that the vertical pipes usually have been exposed to the marine elements for several years, if not decades. This exposure typically causes excess rust to form on steel components of the vertical pipes, particularly around the flanges and flange bolts that are used to connect sections of vertical pipe. The excess rust can significantly delay the removal of vertical pipes because of the added difficulty in removing flange bolts. These delays can add to the costs of decommissioning, which have been estimated to be in the range of $15 million to $20 million for removal of a complete platform in shallow waters such as the Gulf of Mexico. These costs are typically borne by the lease operator, who is consistently searching for ways to reduce costs of decommissioning. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a means for reducing the costs of decommissioning abandoned oil and gas platforms by significantly decreasing the time it takes to remove rusted flange bolts from a vertical pipe. 
     These and other objects and advantages are achieved by the novel flange bolt cutter of the present invention. The flange bolt cutter may have a circular saw assembly including a circular saw blade, and a flange band assembly including an adjustable band having an outer surface and an inner surface. The circular saw assembly may be pivotally connected to the outer surface of the adjustable band. The adjustable band may be capable of detachable fixation around a midpoint between two flanges bolted together by a plurality of flange bolts. The inner surface of the adjustable band includes an alignment means capable of aligning the circular saw blade at the midpoint for cutting the plurality of flange bolts. 
     The circular saw assembly may include a motor for rotatably driving the circular saw blade. The motor is a hydraulically operated motor. 
     The circular saw assembly may include a blade case substantially covering an upper portion of the circular saw blade. The circular saw blade may have a serrated outer cutting edge. The serrated outer cutting edge may contain a carbon coating. 
     The circular saw assembly may include a mounting assembly for pivotal connection to the outer surface of the adjustable band. The mounting assembly may include a bracket pivotally connected to the outer surface of the adjustable band and one or more arms detachably connected to the bracket and to the blade case. The bracket and the blade case each may have two opposing sides. The mounting assembly may have two arms. One of the arms may be detachably connected to one of the opposing sides of the bracket and the blade case. The other arm may be detachably connected to the other opposing sides of the bracket and blade case. Each opposing side of the mounting bracket may include a cylinder guide affixed thereto. Each opposing side of the blade case may include one or more cylinder guides affixed thereto. The cylinder guides affixed to the bracket and the cylinder guides affixed to the blade case each may accommodate one of the arms. 
     The two arms may be adjustable about the cylinder guides affixed to the bracket and to the blade case. The cylinder guides affixed to the bracket and to the blade case each may contain at least one recess. The arms may contain a plurality of recesses. The arms may be adjustably connected to the cylinder guides by aligning one of the plurality of recesses in the arms with the at least one recess in each of the cylinder guides and extending a bolt from a plurality of bolts through each of the aligned recesses. 
     The adjustable band may comprise two band sections pivotally connected together by a hinge. The flange band assembly may include a detachable fixation means capable of detachably affixing the adjustable band about the midpoint of the two flanges. The detachable fixation means may include two adjusting nuts. One of the adjusting nuts may be affixed to one of the band sections. The other adjusting nut may be affixed to the other band section. An adjusting bolt may extend through each of the adjusting nuts. Rotation of the adjusting bolt in a first direction causes the nuts to move toward each other thereby tightening the band sections. Rotation of the adjusting bolt in a second direction causes the nuts to move away from each other thereby loosening the band sections. The adjusting bolt contains a handle for rotation thereof. 
     The two arms may contain a handle capable of being manipulated to lower the circular saw blade to a cutting position and to raise the circular saw blade to a non-cutting position. 
     The alignment means may include a raised ring projection capable of wedging into the midpoint between the two flanges. The raised ring projection may extend partially around the inner surface of the adjustable band. The adjustable band may have an opening for passage of the circular saw blade there-through to enable the circular saw blade to cut through one of the plurality of flange bolts. The raised ring projection may not extend into the opening. 
     These and many other objects and advantages will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims and the following detailed description of the preferred embodiments and read in conjunction with the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side perspective view of an embodiment of the flange bolt cutter assembly of the present invention engaged on a flange. 
         FIG. 2  is a top perspective view of the embodiment of the flange bolt cutter assembly shown in  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the embodiment of the flange bolt cutter assembly shown in  FIG. 2  taken along lines  3 - 3 . 
         FIG. 4  is a partially exploded side perspective view of an embodiment of the flange bolt cutter assembly of the present invention shown with the flange band assembly in an open position. 
         FIG. 5  is a top perspective view of the embodiment of the flange bolt cutter assembly shown in  FIG. 4  but with the flange band assembly in a closed position. 
         FIG. 6  is a partial cross-sectional view of the embodiment of the flange bolt cutter assembly of the present invention shown in  FIG. 3  at  6 . 
         FIG. 7  is a partial cross-sectional top view of the embodiment of the flange bolt cutter assembly shown in  FIG. 1  in cutting position. 
         FIG. 8  is a cross-sectional view of the embodiment of a flange bolt cutter assembly of the present invention shown in  FIG. 2  taken along lines  8 - 8 . 
         FIG. 9  is a cross-sectional view of the embodiment of a flange bolt cutter assembly of the present invention shown in  FIG. 2  taken along lines  9 - 9 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While the present invention will be described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the present invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention. 
       FIG. 1  shows flange bolt cutter  10  operatively engaged about two flanges  11  that are secured together by flange bolts  12 . Flange bolt cutter  10  includes a saw assembly  20 , a pivot assembly  40 , and a flange band assembly  60 . Saw assembly  20  includes a circular saw blade  21 , a motor  22  for rotatably driving said circular saw blade  21 , and a blade case  23  for substantially covering the upper portion of said circular saw blade  21 . Circular saw blade  21  is preferably equipped with carbide tips. Circular saw blade  21  is also preferably sufficiently thin to fit through typical gaps between flanges that are bolted together. 
     As seen in  FIGS. 2 and 3 , motor  22  is mounted to side wall  25  of blade case  23 . Motor  22  is preferably, but not necessarily, powered by hydraulic fluid, which is typically transferred to and from motor  22  via hydraulic hoses (not shown). Blade case  23  supports saw shaft  24  extending through side wall  25  from motor  22 . Circular blade saw  21  is detachably secured to saw shaft  24  on the end opposite motor  22 . 
     With reference to  FIGS. 4 and 5 , blade case  23  is equipped with a set of cylinder guides  26  for accommodating pivot arms  42  of pivot assembly  40 , as discussed below. Pivot assembly  40  preferably includes mounting bracket  41 , pivot arms  42 , and handle  43 . 
     As seen in  FIGS. 4 ,  8  and  9 , mounting bracket  41  has a base plate  44 , side plates  45  on opposite sides of said base plate  44 , and a set of cylinder guides  50  for accommodating pivot arms  42 . Each side plate  45  is preferably equipped with a threaded hole  46  through which a threaded bolt  47  threadably fits therein. Each threaded bolt  47  preferably has a partially tapered end  48  on the end facing inwardly toward the other rotation plate  45 , and a hex head end  49  on the end facing outwardly away from the other rotation plate  45 . Partially tapered end  48  facilitates the insertion of threaded bolt  47  into a flange hole, while hex head end  49  facilitates the tightening and loosening of threaded bolt  47  onto side plate  45 . 
     Again with reference to  FIGS. 4 ,  5 ,  8  and  9 , pivot arms  42  adjustably extend through the set of cylinder guides  50  on mounting bracket  41  and the set of cylinder guides  26  on saw assembly  20 . Pivot arms  42  are adjustable to allow optimum position of circular saw blade  21  with respect to the bolt  12  that is being cut during the cutting process. Pivot arms  42  have a series of bolt holes  51  that coincide with bolt holes  27  on cylinder guides  26  and  50 , which when aligned at various positions, allow support bolts  52  to be inserted there-through for securing saw assembly  20  at a desired position. Pivot arms  42  are preferably equipped with a handle  43 , which allows the user of bolt cutter  10  to raise and lower circular saw blade  21  between an upper, non-cutting position (as seen in  FIG. 5 ) and a lower, cutting position (as seen in  FIG. 7 ), and anywhere in between. 
     With references to  FIGS. 4 and 5 , flange band assembly  60  preferably includes a flange band  61 , a hinge  62 , and a flange band adjusting assembly  63 . Flange band  61  is preferably constructed of two thin metal semi-circular pieces  64  and  65 . The two semi-circular pieces are connected together at one end using hinge  62 , and connected together at the other end using flange band adjusting assembly  63 , as shown in  FIGS. 1 and 2 . Hinge  62  allows the user of bolt cutter  10  to open flange band  61  to facilitate installation and removal around flange  11 . Flange band adjusting assembly  63 , which preferably includes an adjusting bolt  67 , at least two adjusting nuts  68 , and an adjusting handle  69 , allows the user to tighten flange band  61  around flange  11 . Adjusting nuts  68  may be cylindrically shaped with one or more openings for receiving adjusting bolt  67 . The one or more openings may be positioned on a side surface of each of adjusting nuts  68 . One of adjusting nuts  68  may have an opening through its entire length for receiving adjusting bolt  67 . 
     Again with reference to  FIGS. 4 and 5 , one of the adjusting nuts  68  is cylindrical with a central opening threadedly receiving one end of adjusting bolt  67 . This adjusting nut  68  is pivotally connected to semi-circular piece  64  via spaced-apart closed receptacles  70 . The other adjusting nut  68  has a first cylindrical section  72  and a second cylindrical section  74  positioned perpendicular thereto. Adjusting bolt  67  extends through section  74 . Section  72  cooperates with spaced-apart open receptacles  76  affixed to semi-circular piece  65  when adjusting assembly  63  is tightened around flange  11 . To tighten assembly  63 , assembly  63  is pivoted into the tightening position so that section  72  aligns with receptacles  76 . Adjusting handle  69 , which is threadedly connected to adjusting bolt  67 , is rotated so as to move adjusting nut  68  downward to position section  72  within receptacles  76  which in turn causes semi-circular pieces  64  and  65  to move together thereby fixedly attaching flange band assembly  60  to flange  11  in an operational position. 
       FIGS. 4 ,  5  and  6  show that flange band  61  is equipped with a slot ring  66  along a portion of its surface. Slot ring  66  aligns flange band  61  and circular saw blade  21  with the midpoint  13  between flanges  11  where flange bolts  12  are being cut. Slot ring  66  is omitted from the flange band  61  between flange band adjusting assembly  63  and side plates  45  so as not to interfere with circular saw blade  21  during the cutting process. 
     Although this invention has been disclosed and described in its preferred forms with a certain degree of particularity, it is understood that the present disclosure of the preferred forms in only by way of example and that numerous changes in the details of construction and operation and in the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention.