Abstract:
A method for the circumferential interior treatment of pipe elbows, including a step of positioning a working member within a pipe elbow and moving the working member along a portion of a length of the pipe elbow between selected working positions, while concurrently manipulating the pitch and rotational positioning of the pipe elbow to maintain a concentric rotation of the pipe elbow about the working member.

Description:
FIELD 
       [0001]    The present invention relates to a method for circumferential interior treatment of pipe elbows, applicable to welding, grinding, polishing, and spray coating applications, and an apparatus developed in accordance with the method. 
       BACKGROUND 
       [0002]    U.S. Pat. No. 6,234,383 entitled “Method and apparatus for circumferential application of materials to an interior surface of a curved pipe” discloses an earlier version of apparatus. 
       SUMMARY 
       [0003]    There is provided a method for the circumferential interior treatment of pipe elbows, including a step of positioning a working member within a pipe elbow and moving the working member along a portion of a length of the pipe elbow between selected working positions, while concurrently manipulating the pitch and rotational positioning of the pipe elbow to maintain a concentric rotation of the pipe elbow about the working member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0004]    These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to in any way limit the scope of the invention to the particular embodiment or embodiments shown, wherein: 
           [0005]      FIG. 1  is a transparent end elevation view of an apparatus for the circumferential interior treatment of pipe elbows. 
           [0006]      FIG. 2  is a transparent side elevation view of the apparatus in  FIG. 1 . 
           [0007]      FIG. 3  is a transparent end elevation view of the apparatus in  FIG. 1  with the pipe support and arm rotated 90°. 
           [0008]      FIG. 4  is a side elevation view of the apparatus in  FIG. 1  with the pipe support and arm rotated 90°. 
           [0009]      FIG. 5  is a transparent end elevation view of the apparatus in  FIG. 1  with the pipe support and arm rotated 180°. 
           [0010]      FIG. 6  is a partially transparent side elevation view of the apparatus in  FIG. 1  with the pipe support and arm rotated 180°. 
           [0011]      FIG. 7  is a transparent end elevation view of the apparatus in  FIG. 1  with the pipe support and arm rotated 270°. 
           [0012]      FIG. 8  is a side elevation view of the apparatus in  FIG. 1  with the pipe support and arm rotated 270°. 
           [0013]      FIG. 9 through 12  are a series of transparent side elevation view of the apparatus in  FIG. 1  showing the workpiece being withdrawn. 
       
    
    
     DETAILED DESCRIPTION  
       [0014]    An apparatus for the circumferential interior treatment of pipe elbows generally identified by reference numeral  10 , will now be described with reference to  FIG. 1 through 12 . 
         [0015]    Structure and Relationship of Parts: 
         [0016]    Referring to  FIG. 9 , apparatus  10  includes a base  12 , a pipe support  14  mounted for rotation on base  12  about a rotational axis  15 , and an arm support  16 . Arm support  16  is movable toward and away from pipe support  14 , and has a rotatable portion  18  and a fixed portion  20 . Rotatable portion  18  rotates about an axis  19 . An arm  22  has a mounting end  24   25  and a working end  26 . Mounting end  24  of arm  22  is mounted at an angle to rotatable portion  18  of arm support  16 . Arm  22  rotates with rotatable portion  18  of arm support  16 . 
         [0017]      FIGS. 1 and 2  shows arm  22  and a pipe elbow  42  in an upright, starting position;  FIGS. 3 and 4  shows arm  22  and pipe elbow  42  rotated  900 ;  FIGS. 5 and 6  shows arm  22  and pipe elbow  42  rotated 180°; and  FIGS. 7 and 8  shows arm  22  and pipe elbow  42  rotated 270°. Referring to  FIG. 9 , there is a working member  28  positioned at a working end  26  of arm  22 . The working member  28  is pivotally mounted to working end  26  such that, referring to  FIG. 1 through 8 , working member  28  is maintained in a vertical position pointing downward as arm  22  rotates. As can be seen, the angle of arm  22  is chosen such that working member  28  maintains the desired height as arm  22  rotates. A linkage  30  extends through arm  22  and connects to working member  28 . Linkage  30  moves with rotatable portion  18  while maintaining a constant orientation. Thus, as arm  22  rotates, the proper orientation and height of working member  28  is maintained. It will be recognized that, while a substantially constant height and orientation is maintained, some movement of working member  28  may be preferred in some circumstances. For example, when used in a welding application, it may be desired to have working member  28  oscillate. 
         [0018]    There are different ways of extending working end  26  of arm  22  into pipe support  14  and between selected working positions. In the embodiment illustrated in  FIG. 9 through 12 , arm supports  16  are mounted to tracks  32 . A motor  36  is provided, which applies the force to move arm support  16  in either direction. Arm support  16  is connected to tracks  32  either directly or by a support frame  38  as shown.  FIG. 9 through 12  show arm support moving progressively away from pipe support  14  at different stages of the treatment. 
         [0019]    There is a pipe receiver  40  positioned within pipe support  14  that rocks to control the pitch of a pipe elbow  42  supported by pipe support  14 . This is done to maintain a concentric rotation of pipe elbow  42  about working end  26  of arm  22  where working member  28  is located. Pipe receiver  40  has a first end  44  and a second end  46 . First end  44  has outwardly projecting pins  48  which travel along slots  50  in pipe support  14 . As shown, front pistons  52  and rear pistons  54  are used to raise and lower first end  44  and second end  46  of pipe receiver  40 , respectively, to control the pitch of pipe receiver  40  and therefore pipe elbow  42 . Other power sources may be used to provide the vertical control of pipe support  14 . As first end  44  and second end  46  of pipe receiver  40  are raised and lowered, pins  48  at first end  44  of pipe receiver  40  travel along the slots  50  to maintain the proper lateral position of pipe receiver  40 . 
         [0020]    Referring to  FIG. 1 , pipe support  14  is rotatably supported on base  12  by trunnion wheels  57  at the front and back and on each side. Since timing is important, pipe support  14  is rotated by a positive drive. As shown, the positive drive includes a motor  58  that is connected by a drive chain  62  to an engagement wheel  60  of pipe support  14 . Other positive drives will be apparent to those skilled in the art, such as a gear drive. As motor  58  applies a force to chain  62 , engagement wheel  60  is rotated, which in turn rotates pipe support  14  and pipe receiver  40  through the positions shown in  FIG. 1 through 8 . Referring to  FIG. 9 , motor  58  also controls the rotation of rotatable portion  18  of arm support  16  by driving a drive shaft  64 , which is in turn connected to a drive chain  66 . In this way, the rotation of both pipe support  14  and rotatable portion  18  are synchronized. 
         [0021]    Operation: 
         [0022]    The use and operation of apparatus  10  will now be described. Referring to  FIG. 9 , pipe elbow  42  is mounted in pipe receiver  40  which is supported by pipe support  14 . Pistons  52  and  54  are used to adjust pipe receiver  40  to obtain the desired starting position, and arm support  16  is advanced along tracks  32  using motor  36  to position working member  28  carried by arm  22  within pipe elbow  42 . In one example, the process is started with working member  28  positioned halfway into pipe elbow  42 . Once working member  28  has reached the end of pipe elbow  42 , it may then be reversed to treat the other half of pipe elbow  42 . Referring to  FIGS. 1 ,  3 ,  5  and  7 , motor  58  causes engagement wheel  60  to rotate via chain  62  in order to rotate pipe support  14  and therefore pipe elbow  42 . As pipe elbow  42  is being rotated through a full circle, referring to  FIGS. 2 ,  4 ,  6  and  8 , motor  58  also rotates a drive shaft  64  which in turn rotates rotatable portion  18  of arm support  16  such that arm  22  rotates at the same rate as pipe elbow  42 . However, during rotation through these positions, it will be noted that working member  28  maintains its initial orientation and position. Referring to  FIG. 9 through 12 , as pipe elbow  42  is being rotated and treated as described above, arm support  16  and therefore working member  28  is repositioned by motor  36  while pistons  52  and  54  adjust the pitch of pipe receiver  40  and therefore pipe elbow  42 . Pins  48  in slots  50  maintain the lateral position of pipe receiver  40 . The process described and depicted allows the user to treat the inside of pipe elbow  42  using a helical pattern. The pitch of the helix may be adjusted based on the preferences of the user. It will also recognized that apparatus  10  may treat pipe elbows  42  using different patterns, such as in bands. In any event, the portion of pipe elbow  42  being treated is properly positioned such that it is centred about rotational axis  14  to ensure that the distance between working member  28  and the inside of pipe elbow  42  is constant during rotation. Once the first half of pipe elbow  42  has been treated, pipe elbow  42  is removed from pipe receiver  40 , reversed, and replaced such that the other half of pipe elbow  42  may be treated. As pipe elbow  42  rotates, it may be useful to have motor  58  adjust its speed to have a more consistent treatment along the inside of pipe elbow  42 . Since working member  28  applies a treatment, such as a weld, at a constant rate, it may be necessary to accelerate the rotation of pipe elbow  28  while the “short” portion of the bend is being treated, and to slow the rotation of pipe elbow  28  while the “long” portion of the bend is being treated to ensure it is treated evenly. It will also be recognized that, while  FIG. 1 through 7  depicts working member  28  treating pipe elbow  42  from the centre outward to the end of pipe elbow  42 , apparatus  10  could also be operated such that arm support  16  moves working member  28  from the end toward the centre of pipe elbow  42 . Furthermore, in some circumstances, it may be possible to treat the entire inside of pipe elbow  42  without having to have it removed and reversed. 
         [0023]    Advantages: 
         [0024]    The apparatus described in U.S. Pat. No. 6,234,383 moved the pipe elbow along tracks. This required tracks for every size of pipe and every radius. The method and apparatus described above eliminates the need for tracks, as the pipe elbow remains in a constant axial position while the working head moves. This change in movement enables the pipe elbow to be serviced from either end. When working on an elbow, a sufficient portion such as half can be treated from one end and then the elbow can be reversed in the pipe support and the remaining portion can be treated from the other end. The method and apparatus were developed for use in welding, but can potentially be used for numerous other operations, such as grinding, polishing, and coating application. 
         [0025]    In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements. 
         [0026]    It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiments without departing from scope of the claims.