Abstract:
An apparatus for altering a surface of a cylindrical object includes at least one container containing a fluid resist therein and having at least one opening from which the fluid resist is discharged; at least one roller operatively associated with the at least one container and having a surface sized and shaped to be exposed to the at least one opening, the surface area including a pattern of shapes and upon which the fluid resist is deposited; and at least one support member adjacent the at least one roller for supporting the cylindrical object during transit for contacting the at least one roller. A method is also provided.

Description:
BACKGROUND 
       [0001]    The present embodiments relate to altering the surface area of cylindrical objects, such as for example pipes and tubes, for increasing heat transfer at same. 
         [0002]    It is desirable to increase a surface area of pipes and tubes (collectively “piping”) in order to increase their heat transfer efficiency. Such pipes are used in, for example, heat exchangers and condensers. Known methods include chemical or mechanical joining of fins or wings to existing piping to increase the surface area of said piping to bring about heat transfer efficiency. However, these known processes are labor intensive, which results in increased cost, and are limited in the temperature and the fabrication of the surface area of the piping. For example, the fins which are welded or joined to the piping are usually limited to a lower temperature and are expensive to fabricate due to the exacting tolerances required of the fins. 
         [0003]    In addition, certain alloys cannot be used to fabricate the fins because of the metallurgical or other physical differences between the fins and the base metal used for the existing piping. The physical or molecular differences between the material of the fins and the base metal of the piping may sometimes result in incompatibility of these elements such that the structural integrity of the piping is compromised due to the weakened joint between the components. 
         [0004]    It is also common for fins only to be available in certain repetitive shapes that disallow for novel, particular patterns that could be used to further enhance turbulent or other fluid effects during the heat transfer. While mechanical machining allows almost all types of metals to be machined for the piping, the cost to do so for a myriad of different types of pipes can be unusually expensive, and therefore the related cost for the area to have an increased ratio of surface heat transfer effect by direct machining of said surface is generally prohibitive. 
         [0005]    It would therefore be desirable to have an apparatus and method for use with all types of metallic piping to increase the heat transfer effect at a surface of said piping with minimal labor and material costs. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    For a more complete understanding of the present embodiments, reference may be had to the following description taken in conjunction with the drawing Figures, of which: 
           [0007]      FIG. 1  shows a side view in cross-section of an embodiment of a surface relief apparatus of the present invention; 
           [0008]      FIG. 2  shows an end view in cross-section of another embodiment of a surface relief apparatus; 
           [0009]      FIGS. 3A-3C  show portions of top plan views of different surface relief provided by the apparatus of  FIGS. 1 and 2 ; and 
           [0010]      FIG. 4  shows an embodiment of a method which may be used to provide surface relief to cylindrical objects such as piping. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    Referring to  FIG. 1 , an embodiment of a surface relief apparatus of the present invention is shown generally at  10 . The apparatus  10  is used to deposit “resist” on a surface area of cylindrical tubing  12 , such as for example pipes, conduits and other objects of similar construction. 
         [0012]    The apparatus  10  includes at least one printing wheel  14  or alternatively, as shown in  FIG. 1 , a pair or a plurality of the printing wheels for coacting with the pipe  12 . If a pair of the printing wheels  14  are used, such pair will be spaced apart a distance sufficient to receive the pipe  12  therebetween for deposition of the resist as describe hereinafter. 
         [0013]    Disposed adjacent to and for coaction with the printing wheel  14 , roller or drum is a reservoir  16  in which is contained a fluid resist  17  for being deposited on a surface  18  of the pipe  12 . Again, it is possible to use one of the reservoirs  16  for a corresponding one of the printing wheels  14  used in the apparatus  10 , as shown for example in  FIG. 1 . Each one of the printing wheels  14  has a surface area  20  which is in fluid communication with the reservoir  16  for receipt of the liquid resist on to the surface  20  of the printing wheel. It is possible that either the reservoir  16  or the wheel surface  20  will have the particular pattern that is to be assumed by the resist and transferred onto the surface  18  of the pipe. As the printing wheel  14  rotates, the surface  20  of the wheel is coated with the fluid resist  17  from the reservoir  16  such that the resist is thereafter deposited as a specific pattern on the piping surface  18 . 
         [0014]    At least one bearing  22  or support member is used to support the pipe  12  for introduction adjacent to or between the printing wheels  14  so that deposition of the resist  17  on the surface  18  of the pipe is sufficient and uniform according to the desired application pattern. The bearing  22  or bearings can be roller bearings. 
         [0015]    A direction of travel of the pipe  12  with respect to the apparatus  10  is shown generally by arrow  24 . 
         [0016]    Referring also to  FIG. 2 , another embodiment of the surface relief apparatus is shown generally at  26 . In this apparatus  26 , a plurality of the printing wheels  14  are used such that the entire surface  18  of the pipe  12  is covered in the select pattern of the resist  17  to be deposited. Each one of the printing wheels  14  may have its own corresponding reservoir  16  of the fluid resist  17 . Alternatively, each one of the printing wheels  14  is in fluid communication with a common reservoir which functions as a manifold or plenum to supply the fluid resist  17  to each one of the plurality of printing wheels. 
         [0017]      FIGS. 3A-3C  show the different patterns or shapes of resist that can be deposited on the surface  18  of the pipe  12 , as for example “microbumps”. A pattern of resist bumps  25   a  shown in  FIG. 3A , chevrons  25   b  shown in  FIG. 3B  or diagonals  25   c  shown in  FIG. 3C , can be deposited on the pipe surface  18 . Alternatively, any number of these shapes  25   a - c  or a combination of same in a corresponding pattern can be used for deposition on the pipe surface  18 . That is, the patterns shown in  FIGS. 3A-3C  are formed in relief on the surface  20  of each printing wheel  14  so that the fluid resist  17  is deposited on the elevated pattern for subsequent deposition on the cylindrical tubing  12 . The microbumps may extend, by way of example only, approximately 1 mm above the pipe surface  18 .  FIGS. 3A-3C  also show for example an area of 1.60, 1.76 and 2.83 square inches, respectively, of the pipe surface  18  having the bump pattern. 
         [0018]    In  FIG. 4 , a method is shown generally at  30  for having the pipe  12  etched with surface relief of the patterns from, for example,  FIGS. 3A-3C  or any other pattern desired, to provide increased surface area and therefore increased heat transfer effect at the pipe surface  18 . 
         [0019]    In operation of the method, a particular type of the pipe  12  is selected  32  for etching. A pipe or tubing cache can be staged in any manner. Thereafter, each one of the pipes  12  are provided to the surface relief apparatus  10  in the step  34  for deposition of the fluid resist  17  in a select pattern on the surface  18  of the pipe. The pattern selected may be that shown in  FIGS. 3A-3C , for example. When the pipe  12  emerges from the apparatus  10 , the pipe is subjected to a drying step  36  for drying and stabilizing the resist  17 . Alternatively, if the fluid resist  17  is an epoxy, such may be cured with ultraviolet (UV) or visible light. Thereafter, the pipe  12  is subjected to an etching step  38  which will remove a select amount of the surface  18  of the pipe  12  that is not protected by the fluid resist  17  pattern. After the etching step  38 , the pipe  12  is subjected to a wash  40  for removing or neutralizing the particular etching substance used in the step  38 . The washing can be done with water or deionized water, for example. If an acid etchant is used for the etching  38 , more than likely a neutralizing agent for the acid will have to be used to neutralize any remaining acid on the surface  18  of the pipe  12 . After neutralizing, the pipe surface  18  may also be washed. After the neutralizing and/or washing step  40 , the resist  17  must be removed and this can be done in a removal step  42  which may include heat lamps or other heating elements to burn off and/or dissolve the resist  17 . It is also possible to remove the resist with a chemical treatment to dissolve the resist from the pipe  12 . The result will be that the surface area  18  of the pipe  12  has been etched or worn away except for the particular pattern of microbumps which remain due to the resist  17  deposited during the resist deposition step  34 . Thereafter, the pipe  12  having a new surface relief with a select pattern of, for example, the shapes of  FIGS. 3A-3C , and corresponding heat transfer effect will be provided for subsequent processing, such as cutting, bending, painting, graphics, mechanical attachments, etc., or for immediate use by an end user  44 . 
         [0020]    The surface relief apparatus  10 , 26  could alternatively employ either electrostatic, laser or ion deposition of the fluid resist  17 . Photolithography is also possible for deposition of the fluid resist  17  for the step  34 . 
         [0021]    The fluid resist  17  used may be a resin epoxy which would resist a particular etchant chosen. Depending upon the chemistry used in the etchant or wash step  40 , this would determine the type of fluid resist  17  used. For example, during electrolytic etching, a basic inorganic fluid resist  17  may be sufficient. However, if acid etching is used for the etching step  38 , a resin epoxy as the fluid resist  17  could be used at the surface  18  of the pipe  12 . An adhesive polymer may also be used for the resist  17 . 
         [0022]    Similarly, the etchant solution for the step  38  would also be dependant upon the material type of the pipe  12 . For example, if the pipe  12  is high in nickel content, this would require a fluorinated compound (hydrofluoric) etchant, while a sodium hydroxide would be sufficient for etching a stainless steel pipe. A carbon steel or chromium-molybdenum steel could be etched with an electrolytic process containing sodium chloride. 
         [0023]    Regarding the patterns of  FIGS. 3A-3C , such as presented are examples only and are not meant to be limiting. It is submitted that a cost-benefit analysis may be performed of the etching solution cost versus the metal of the pipe  12  to be etched. In other words, if the pipe  12  is constructed from a particular material, certain of the patterns for  FIGS. 3A-3C  would be desirable depending upon convection and radiation requirements of the pipe. 
         [0024]    It will be understood that the embodiments described herein are merely exemplary, and that one skilled in the art may make variations and modifications without departing from the spirit and scope of the invention. All such variations and modifications are intended to be included within the scope of the invention as described and claimed herein. Further, all embodiments disclosed are not necessarily in the alternative, as various embodiments of the invention may be combined to provide the desired result.