Abstract:
A pipe electrochemical polishing system ( 10 ) for in place polishing of a pipe ( 12 ) has a cathode puller cable ( 16 ) having a plurality of balls ( 34, 34   a ) distributed along the length of the cable ( 16 ). The balls ( 34, 34   a,    34   b ) support the cable ( 16 ) within the pipe ( 12 ) and provide rigidity to the cable ( 16 ) so that the cable ( 16 ) can be pushed through the pipe ( 12 ) rather than having to be initially pulled therethrough. The cable ( 16 ) can be readily pulled through the pipe ( 12 ), and particularly around bends therein, because the balls ( 34, 34   a,    34   b ) prevent the cable ( 16 ) from binding and coming into contact with the interior walls of the pipe ( 12 ).

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates to the field of electrochemical processing, and more particularly to an apparatus and method for providing for longer pulls, including a greater number of turns, when pulling an apparatus through a pipe by a cable, or the like. The predominant current usage of the present inventive improved pipe electropolishing apparatus and method is for the in place polishing of pipes used in fluid and liquid chemical processing facilities.  
         BACKGROUND ART  
         [0002]    It is known in the art to deposit and/or remove materials by passing an electric current through a fluid electrolyte which is in contact with a conductive electrode. Materials are exchanged between the electrolyte and the electrode depending upon the direction of current flow and the ionization of materials to be deposited on or removed from the electrode. Electroplating is a well known application of this general method. Electropolishing is also well known in the art. In the electropolishing process, irregularities and deposits on a surface are removed by causing material on the surface to be drawn into the electrolyte solution.  
           [0003]    An example of an electropolishing process is the in place electrochemical polishing of the inner surface of a pipe. In this process, a cathode is drawn through the pipe by a cable while an electrolyte solution is simultaneously pumped through the pipe. The pipe acts as an anode and is electrochemically polished in the process. Since the electrolyte solution must be continuously pumped through the pipe during the process, it is most practical to recirculate the solution.  
           [0004]    A piping system will generally consist of straight sections of pipe and of bent sections joining such straight sections. According to prior art methods, it has been quite difficult to pull the cable through the pipe, particularly where the length of pipe is long, and even more particularly when the cable must traverse a great number of bends or turns. For example, prior art systems have been able to negotiate a maximum of approximately seven right angle bends. Even when limiting the number of bends and also limiting the length of pipe to be traversed, it has been quite difficult to pull the cable through the pipe, often stalling the motor used to do the pulling.  
           [0005]    Another problem with conventional cable pulling systems is that it is very difficult to thread the cable through the pipe in the first place. Devices such as a pull tape are pushed through a section of the pipe, the cable is attached to the tape and then pulled through. This initial insertion operation is so difficult and time consuming that it frequently takes more time than all of the rest of an in place pipe electropolishing process combined.  
           [0006]    It would be advantageous to have a method or apparatus for pulling a cable through a pipe which would allow the cable to pull more easily through the pipe, such that a longer length of pipe and/or more bends could be traversed. It would further be advantageous to have some method or apparatus whereby the threading of a cable through a pipe could be made easier. However, to the inventor&#39;s knowledge, no such method or apparatus to accomplish either of these purposes has existed in the prior art.  
         SUMMARY  
         [0007]    Accordingly, it is an object of the present invention to provide an apparatus and method for causing a cable to pull more easily through a pipe.  
           [0008]    It is another object of the present invention to provide an apparatus and method for allowing a cable to more easily traverse bends in a pipe.  
           [0009]    It is yet another object of the present invention to provide an apparatus and method for easily threading a cable through a pipe.  
           [0010]    It is still another object of the present invention to provide an apparatus and method for improving an in place pipe electropolishing process.  
           [0011]    Briefly, a known embodiment of the present invention has a plurality of balls generally evenly spaced along the length of a cable. In this embodiment, the cable is affixed to the ball at the center of the ball. As the cable is pulled through a pipe, the balls suspend the cable in the pipe such that the cable generally does not come into contact with the walls of the pipe. Since the balls are made from a low friction material, the balls allow the cable to be easily pulled through the pipe. In pipe bends, wherein the cable has previously been pressed against an inside bend of the pipe corner, the balls also tend to hold the cable away from the pipe and prevent this source of additional drag.  
           [0012]    The balls are spaced on the cable such that the cable can be fed through the pipe without the aid of a separate puller tape or cable. That is, the cable, with balls attached, is fed through the pipe in a first direction prior to the commencement of a polishing operation. Then, electrical current is provided to begin the pipe electropolishing operation and the cable is pulled through the pipe generally in the direction opposite to the first direction.  
           [0013]    These and other objects and advantages of the present invention will become clear to those skilled in the art in view of the description of modes of carrying out the invention, and the industrial applicability thereof, as described herein and as illustrated in the several figures of the drawing. The objects and advantages listed are not an exhaustive list of all possible objects or advantages of the invention. Moreover, it will be possible to practice the invention even where one or more of the intended objects and/or advantages might be absent or not required in the application.  
           [0014]    Further, those skilled in the art will recognize that various embodiments of the present invention may achieve one or more, but not necessarily all, of the above described objects and advantages. Accordingly, the listed objects and/or advantages are not essential elements of the present invention, and should not be construed as limitations. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is block diagrammatic view of an example of an in place pipe electropolishing system, according to one example of the present invention;  
         [0016]    [0016]FIG. 2 is an exploded front elevational view of an example of a ball, according to the present invention;  
         [0017]    [0017]FIG. 3 is a side elevational view of the ball of FIG. 2;  
         [0018]    [0018]FIG. 4 is a cross sectional front elevational view of another example of a ball, according to the present invention;  
         [0019]    [0019]FIG. 5 is a cross sectional side elevational view of another example of a ball, according to the present invention;  
         [0020]    [0020]FIG. 6 is a front elevational view of the example of the ball of FIG. 5; and  
         [0021]    [0021]FIG. 7 is a diagrammatic top plan view of an example of the cable puller of FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    The embodiments and variations of the invention described herein, and/or shown in the drawings, are presented by way of example only and are not limiting as to the scope of the invention. Unless otherwise specifically stated, individual aspects and components of the invention may be omitted or modified, or may have substituted therefore known equivalents, or as yet unknown substitutes such as may be developed in the future or such as may be found to be acceptable substitutes in the future. The invention may also be modified for a variety of applications while remaining within the spirit and scope of the claimed invention, since the range of potential applications is great, and since it is intended that the present invention be adaptable to many such variations.  
         [0023]    Unless otherwise stated herein, component parts of the invention will be familiar to one skilled in the art, and may be purchased or readily manufactured accordingly. Also, unless otherwise stated herein, substitutions can be made for the components described, and each of the individual components, except as specifically claimed, is not an essential element of the invention.  
         [0024]    A known mode for carrying out the invention is an in place pipe electrochemical polishing system  10  for polishing the inner surface of a pipe  12 . While the invention is illustrated in this example as an “in place” system, wherein the inner surface of the pipe  12  is polished without removing it from its usual place, one skilled in the art will recognize that the invention could be adapted for use in other locations. The in place pipe electrochemical polishing system  10  is depicted in a block schematic diagrammatic view in FIG. 1. As one skilled in the art will recognize, some of the component parts of the in place pipe electrochemical polishing system  10  are a cathode  14 , a cathode puller cable  16 , an electrolyte reservoir  22  for containing a supply of an electrolyte  24 , and an electrolyte pump  26 , all of which are provided for the purpose of polishing the interior of the pipe  12 .  
         [0025]    An inventive cable puller  30  differs from conventional devices as will be discussed in greater detail hereinafter. A cable take up apparatus  32  coils the cable  16  as the cable  16  is drawn out of the pipe  12  by the cable puller  30 . As can be seen in the view of FIG. 1, a plurality of balls  34  are generally evenly spaced along at least a portion of the length of the cable  16 . In the example shown in the view of FIG. 1, the balls  34  are separated on the cable  16  by approximately the diameter of the balls  34  which, for purposes of this example only, is approximately three inches. One skilled in the art will recognize, in light of this present disclosure, that the diameter of the balls  34  and the relative spacing thereof on the cable  16  will be adaptable to the specific application, most particularly to the diameter of the pipe  12  to be electropolished and other variables such as the inherent stiffness of the cable  16 , and the like.  
         [0026]    In the electrochemical polishing process, the cathode  14  is drawn toward the cable puller  30  by the cathode puller cable  16 , while electrical current is applied through the cathode  14  from a power supply  36 . The current flows through the electrolyte  24  in the pipe  12 , which shares a common ground with the power supply  36 , such that the pipe  12  acts as an anode and the interior thereof is polished according to the known principles of electropolishing. During the process, the electrolyte  24  is generally pumped to flow through the pipe  12  in a direction opposite that in which the cathode  14  is being drawn (although such flow can be reversed, if desired, for reasons not relevant to the practice of this present invention).  
         [0027]    As can be seen in the view of FIG. 1, the pipe  12  has straight sections  40  and bent sections  42 , as will be discussed in greater detail, hereinafter. The present example of the in place pipe electrochemical polishing system  10 , as shown in FIG. 1, has components not directly relevant to the explanation of the present invention, such as a pair of filters  44 , a collector sump  46  and a sump pump  48  for moving the electrolyte from the collector sump  46  into the electrolyte reservoir  22 .  
         [0028]    [0028]FIG. 2 is an exploded front elevational view of one example of one of the balls  34  of FIG.  1 . As can be seen in the view of FIG. 2, the ball  34  grips the cable  16  generally only at a center portion  50  of the ball  34 . In this example, the ball  34  is formed in a first ball half  52  and a second ball half  54 , and the first ball half  52  and the second ball half  54  are recessed to accept the cable  16 , as shown in the view of FIG. 2. In this example, the ball halves  52  and  54  are joined together by a screw  56  and nut  58 . The screw  56  is offset from the center axis of the ball  34  such that the screw  56  does not pass through the cable  16 .  
         [0029]    In this present example of the invention, the balls  34  are machined. However, it is anticipated by the inventor that it will be more economical to mold the balls  34  when they are made in greater quantities. In the presently described embodiment of the invention, the balls  34  are made of polypropoline, although they might be made from any of a number of material types which could withstand exposure to the electrolyte  24  and the abrasion to which the balls  34  will be subjected according to the method described herein. An example of such an alternative material is Teflon™.  
         [0030]    [0030]FIG. 3 is a side elevational view of the ball  34  of FIG. 2, showing the second ball half  54  thereof. As can be seen from this view, the ball has a recess  60  for accepting the screw  56  (FIG. 2) such that the head of the screw  56  does not project outside the general circumference of the ball  34 . In applications wherein the nut  58  (FIG. 2) is used, the first ball half  52  (not shown in the view of FIG. 3) will have a similar recess for accepting the nut  58 . An aperture  62  is generally positioned in the center of the recess  60  for passing the screw  56  (FIG. 2) therethrough. As discussed above in relation to FIG. 2, the aperture  62  is positioned off center on the ball half  54 .  
         [0031]    [0031]FIG. 4 is a cross sectional front elevational view of an example of another possible construction of a ball  34   a.  The ball  34   a  has a slot  63  into which the cathode puller cable  16  is introduced. An alternative screw  56   a  is threaded into a threaded aperture  64  in the ball  34   a  to hold the ball  34   a  in place on the cathode puller cable  16  . An optional pressure plate  66  may be used to prevent the screw  56   a  from damaging the cathode puller cable  16 . A recess  60   a  prevents the screw  56   a  from projecting outside the limits of the ball  34   a.    
         [0032]    [0032]FIG. 5 is a cross sectional side elevational view of yet another example of a ball  34   b.  The example of FIG. 5 is of a type which has actually been used by the inventor in the practice of this present invention. The ball  34   b  is molded about the cable  16  such that the ball grips the cable  16  generally around the center of ball  34   b.  However, as can be seen in the view of FIG. 5, the ball  34   b  is formed such that there is a generally conical recess  68  where the cable  16  enters and exits the limits of the ball  34   b.  The inventor has found that providing the general conical recess  68  allows the cable  16  to bend more readily around corners, and the like, without damaging either the cable  16  or the ball  34   b.  As can be seen in the view of FIG. 5, the walls of the generally conical recess  68  can, optionally, be curved slightly to support the cable  16  as it might bend within the ball  34   b.  The exact shape of the conical recess is subject to some variation, depending upon the size and inherent stiffness of the cable  16 , and the like. No particular exact shape has been determined to be superior for the practice of the invention. FIG. 6 is a front elevational view of the ball  34   b  of FIG. 5, showing the cable  16  in cross section. As can be seen in the view of FIG. 6, the generally conical recess  68  approximates a circle about the cable  16 , as seen from this view.  
         [0033]    The examples given are only a few of the possible constructions of balls  34 ,  34   a  and  34   b  which might be used to practice the present invention. A great many variations of the balls  34 ,  34   a  and  34   b  are possible for use with the present inventive apparatus and method. As just one example, the first ball half  52  could be threaded to accept the screw  56 , thereby eliminating the need for the nut  58 . Another alternative would be to use an alternative ball (not shown) which grips the cable  16  generally across the entire diameter of the ball. In such an example, it might be possible to mold such alternative balls (not shown) onto the cable  16 . Yet another of the many possible variations to the ball  34  would be to use more than one screw  58 , or to position the screw  56  differently than in the examples shown, or the like.  
         [0034]    [0034]FIG. 7 is a diagrammatic top plan view of the cable puller  30  of FIG. 1. As can be seen in the view of FIG. 7, the cable puller  30  has a first tractor mechanism  70  and a second tractor mechanism  72  between which the balls  34 , with the cable  16  affixed thereto, are drawn. Each tractor mechanism  70  and  72  has a linked chain  74  with a plurality of pins  75  affixed thereto. In the present embodiment of the invention the flexible pins  75  hold a plurality of traction blocks  76  which, in this example, are constructed from an acid resistant rubber material. The traction blocks  76  engage the balls  34 , as can be seen in the view of FIG. 7.  
         [0035]    The linked chains  74  are each positioned on a drive sprocket  77  and a free wheeling sprocket  78  such that the linked chain  74  is advanced between the drive sprocket  77  and the free wheeling sprocket  78 . Each of the drive sprockets  77  is rigidly affixed to a driven gear  80 . The two driven gears  80  are of like size, and are positioned to mesh together such that the linked chains  74  rotate in opposite directions such that the facing portions of the linked chains  74  which abut the balls  34  will move in the same direction when power is applied to the driven gears  80 . A motor (omitted from the view of FIG. 7 in order to better show the inventive aspects of the invention) will be provided to power one of the driven gears. In the embodiment of the invention described herein, the motor is a pneumatic motor which drives one of the driven gears by a drive gear which engages the driven gear  80 .  
         [0036]    As can be seen in the view of FIG. 7, in the particular embodiment of the invention shown, a pair of connecting arms  84  connect the first tractor mechanism  70  to the second tractor mechanism  72 . The connecting arms pivot about the axis of the drive sprockets  77  and the free wheeling sprockets  78 , as shown in the view of FIG. 7. Therefore, by rotating the connecting arms  84 , the distance between the first tractor mechanism  70  and the second tractor mechanism  72  can be adjusted, thereby adjusting the space between opposing traction blocks  76  to adapt the apparatus to the correct configuration for size of the particular ball  34  being used.  
         [0037]    Also visible in the view of FIG. 7 is a diagrammatic representation of the cable take up apparatus  32  of FIG. 1. As can be seen in the view of FIG. 7, the cable take up apparatus  32  has a take up reel  90  for winding the cable  16  there about. In the embodiment of the invention described, the cable take up apparatus  32  is also powered by a pneumatic motor (not shown). Neither power means discussed herein is a necessary aspect of the invention. The cable take up apparatus  32  will generally provide tension such that the cable  16  is wound thereon as it is made available by the cable puller  30 .  
         [0038]    It should be noted that the cable puller  30  and the cable take up apparatus  32  can optionally be housed in a tub (not shown) such that any acid which spills out of the pipe  12  (FIG. 1) will be caught and contained in the tub.  
         [0039]    In the embodiment of the invention shown in FIG. 1 and  7 , the cable puller  30  is a variable speed puller. It is anticipated by the inventor that the cable puller  30  will normally operate in at least two different modes. For example, the cable  16  might be inserted into the pipe  12  at a relatively high rate, such as at about twenty five feet per minute. Then, power will be applied to the cathode  14  and the cable  16  will be extracted from the pipe  12  at a relatively slower rate, such as at about three inches per minute to perform the electropolishing operation.  
         [0040]    Various modifications to the inventive method and apparatus are also quite possible, while remaining within the scope of the invention. For example, the quantity, construction, size, material and/or placement of the balls  34  op the cable  16  could be altered, according to the particular application.  
         [0041]    All of the above are only some of the examples of available embodiments of the present invention. Those skilled in the art will readily observe that numerous other modifications and alterations may be made without departing from the spirit and scope of the invention. Accordingly, the disclosure herein is not intended as limiting and the appended claims are to be interpreted as encompassing the entire scope of the invention.  
         [0042]    Industrial Applicability  
         [0043]    Although the invention has been described herein in relation to a pipe electropolishing apparatus, it should be noted that the invention has application in essentially any situation wherein a cable, wire, tape, or the like is to be pulled through a pipe, conduit, or the like.  
         [0044]    In the presently described embodiment of the invention, it should be noted that the interior of the cable puller  30  mechanism will be exposed to the acid electrolyte  24  and should, therefore, be constructed of acid resistant materials. However, it is within the scope of the invention that a means might be devised to prevent the flow of acid into the cable puller  30 , thereby rendering such materials unnecessary. Optionally, and in some applications, it may be necessary to provide an additional fluid reservoir (not shown) to collect whatever electrolyte  24  might leak from the cable puller  30 .  
         [0045]    It should be noted that the balls  34 ,  34   a  and  34   b  of the present invention act somewhat like a dam to partially restrict the flow of the electrolyte  24  in the pipe. However, the balls  34 ,  34   a  and  34   b  do not provide a perfect seal within the pipe, nor should they, since it is desirable to allow the electrolyte  24  to flow through the pipe  12 , as previously discussed herein.  
         [0046]    According to the present invention, the cathode  14  can be pushed through the pipe  12  by the cable  16  prior to beginning a polishing operation. This avoids the prior art necessity of pulling the cable through the pipe  12  by a guide wire, tape, or the like. Since this preliminary step has been one of the most time consuming and tedious operations in the prior art, a great savings in time, effort, and money is realized according to the present invention. After the cathode  14  is full inserted into the pipe  12 , then power is applied to the cathode  14  from the power supply  36  to begin the polishing operation, and the direction of the cable puller  30  is reversed and slowed, as discussed previously herein, to pull the cathode  14  through the pipe  12  as the polishing operation progresses. Without the balls  34 ,  34   a  or  34   b  affixed to the cable  16 , the cable  16  would either not be sufficiently stiff to push the cathode  14  through the pipe  12 , or else it would be too rigid to bend well around corners and bends in the pipe  12 .  
         [0047]    Yet another aspect of the present invention not yet fully discussed stems from the fact that the ability of the cable  16  to be moved in both directions through the pipe  12  provides yet another advantage. The inventor has discovered that some portions of the pipe  12 , such as bent portions thereof, may require more polishing than other sections of the pipe  12 . The present inventor has addressed this previously by means such as slowing the progress of the cathode  14  in bent sections of the pipe  12  and/or increasing the voltage to the cathode  14  when the cathode  14  is in bent portions of the pipe  12 . However, according to the present invention, this problem can be solved by selectively reversing the direction of the cathode  14  after the cathode  14  has passed through a bent portion such that the cathode  14  passes through the bent portion two or more times, thereby providing the additional polishing action desired in such bent portion.  
         [0048]    The inventive pipe electrochemical polishing system  10  and associated cable  16 , balls  34 ,  34   a,    34   b  and cable puller  30  are intended to be widely used for the in place polishing of the interior of piping systems. Further the inventive cable  16 , balls  34 ,  34   a,    34   b,  cable puller  30  and associated equipment are intended to be widely used wherever a cable, wire, tape, or the like, is required to be pulled through a pipe, conduit, channel, or the like. Since the inventive pipe electrochemical polishing system  10  and associated in place electropolishing method may be readily produced and integrated with existing electropolishing systems, and since the advantages as described herein are provided, it is expected that it will be readily accepted in the industry. For these and other reasons, it is expected that the utility and industrial applicability of the invention will be both significant in scope and long-lasting in duration.