Abstract:
A fluid heating system for heating fluid flowing in a pipe to prevent freezing and ice build up. A controllable variable flow heat exchanger is utilized within the pipe to provide thermal transfer to the fluid flow.

Description:
FIELD OF THE INVENTION 
     This invention relates to preventing ice buildup in a fluid transport pipeline. More particularly, the invention relates to warming a fluid inside of a transport pipeline. 
     BACKGROUND OF THE INVENTION 
     In particular climates it is desired to heat, thaw and prevent the freezing of pipelines. The pipelines are used to transfer fluids, such as water or oil, across a distance, sometimes through areas of cold weather. Presently, heat exchangers are used to keep the fluid in the pipeline from freezing. However, heat exchangers require that the fluid in the pipeline be flowing in order to be effective. Once the fluid stops moving, the heat exchanger is unable to heat the fluid thereby making the system ineffective. Another method to heat fluid in a pipeline is to heat the exterior of the pipeline, which requires the installation of heated lines on the pipe. However, these transfer lines are generally inefficient as much of the heat is lost to the ambient air. 
     Yet another method is to insert a device into the line and use a vacuum to draw the fluid from the line. Once drained the fluid is heated and pumped back into the pipeline. This method is both very labor intensive and requires the special equipment such as vacuum trucks. 
     Therefore, a system for keeping high volumes of fluid from freezing is desired. Further, a system for keeping fluids from freezing with minimal intervention (disassembly of pipelines, draining and down time) is desired. Even further, a system to provide safe, continuous heat over long distance pipelines, and which is transportable to remote locations as a unit is desired. 
     SUMMARY OF THE INVENTION 
     In one form the invention relates to a fluid heating system which may be installed into a pipeline along the length of the pipeline. The fluid heating system is capable of being transported to a pipeline location and to heat fluid flowing through the pipeline. Flowing pipeline fluid may be diverted in a variable amount to be heated in an attached heat exchanger and then returned to the pipeline flow. 
     In one embodiment, the invention includes a fluid heating system having a pipe comprising a fluid input and a fluid output for connecting to a pipeline. A heat exchanger is connected to the pipe via an inlet and an outlet. The heat exchanger inlet diverts a fluid flowing in the pipe into a heat exchanger interior compartment to be heated and then returned from the heat exchanger back to the pipe. A heating line within the heat exchanger interior compartment includes a heated fluid circulating therethrough for heating the diverted fluid. 
     In yet another embodiment, the invention includes a method of heating a fluid flowing in a pipeline, wherein fluid flowing in the pipeline is diverted into an interior compartment of a heat exchanger. The diverted fluid typically requires heating to increase its current temperature. Heated fluid is circulated in a closed heating line within the heat exchanger, wherein the diverted fluid flows through the heat exchanger in physical contact with the heating line and is thereby heated. The heated diverted fluid is returned back to the pipeline flow. 
     In yet another embodiment, the invention includes a transportable fluid heating system having a pipe section with a fluid input and a fluid output each having a flange connected thereto for being connected to a pipeline. A heat exchanger is connected to the pipe in two places via a heat exchanger inlet and outlet. A valve installed in the pipe diverts fluid flowing in the pipeline through the heat exchanger inlet. A closed heating line within the heat exchanger receives a fluid heated to a temperature higher than the diverted fluid. The heated fluid circulates through the heating line for transferring heat from the heated fluid to the diverted fluid. A frame made from a plurality of rigid members is attached to the heat exchanger and to the pipe for securely supporting the heat exchanger and the pipe, and for lifting and transporting the fluid heating system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is disclosed with reference to the accompanying drawings, wherein: 
         FIG. 1  is an exemplary fluid schematic illustration of one embodiment of a fluid heating system; and 
         FIG. 2  is an expanded isometric view of a transportable framed fluid heating system according to one embodiment. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The examples set out herein illustrates several embodiments of the invention but should not be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION 
     Referring generally to  FIGS. 1-2 , there is shown a fluid heating system  100  for integration with fluid carrying pipelines according to one embodiment. To heat the fluid flowing in a pipeline, a transportable fluid heating system  100  is connected in line between sections of pipeline to allow integration of the heating system therein. The heating system may include a pipeline fluid flow portion and a diverted fluid flow portion entering a heat exchanger. The heat exchanger uses heated fluid circulating in a heating line. The heated fluid enters the heat exchanger through a heating line input and flows through the heating line before exiting through a heating line output. The heating line forms a closed loop within the heat exchanger and allows transfer of heated fluid from the exterior of the heat exchanger into an interior compartment of the heat exchanger without leaking heating fluid into the pipeline product itself. A frame supports the fluid heating system and may be used to lift and transport the fluid heating system as an independent system to remote locations. 
     Referring now to  FIGS. 1-2  in more detail, the fluid heating system  100  includes a pipe  103  in fluidic communication with a heat exchanger  117  via heat exchanger inlet  122  and heat exchanger outlet  124 . These vessels are in fluidic communication as fluid that enters pipe  103  at the fluid inlet  101  in direction  102  may be diverted through heat exchanger inlet  122  along path  110  into an interior compartment  118  of heat exchanger  117 . This same fluid then exits the interior compartment  118  of heat exchanger  117  through the heat exchanger outlet  124  back to the pipe  103  along path  112  and then exits pipe  103  through fluid outlet  105  in the direction  104 . The motive force of the fluid is provided by a pipeline  109  when the fluid heating system  100  is installed in line with the pipeline by connecting pipe flanges  120  to corresponding ones of pipeline flanges  111 . Such flanges for connecting together sections of pipe are commonly known to those having ordinary skill in the art. Typically, corresponding flanges are bolted together through bolt holes in the flanges and are sealed in a fluid tight fashion using, for example, gaskets or other suitable sealing material. The fluid heating system  100  may be inserted into a section of pipeline using such flanges as connections into the pipeline. 
     The pipeline carries pressurized fluid which travels therethrough in the direction indicated by directional arrows  102  and  104 , which pressure is sufficient to drive the fluid through the heating system  100  when the system is installed in the pipeline  109  as described above. The amount of fluid diverted from the fluid flow in the pipe  103  through the heat exchanger inlet  122  is controlled by valve  106 . A handle  107  on the valve may be manually rotated to open and close the valve  106  in a continuously variable fashion, which valve may be a butterfly valve as is commonly known to those having ordinary skill in the art. If the valve  106  is partially opened, then an amount of fluid flowing through a pipeline  109  connected to pipe  103  continues flowing through the pipe  103  as indicated by arrow  108  without diversion into the heat exchanger  117 , while a remaining portion is diverted through the heat exchanger as described above. If the valve  106  is completely open then a larger volume of the fluid flowing from an attached pipeline  109  into pipe  103  may travel through the pipe  103  without being diverted into the heat exchanger as compared with a volume of fluid that travels through the pipe  103  when the valve is partially or completely closed. The valve  106  may be of the type that is fitted between pipe flanges  126 ,  128 , such as a wafer and lug style butterfly valve made by C &amp; C Industries of Houston, Tex. 
     The heat exchanger  117  connected to the pipe  103  includes an exterior housing, or wall  119 , a heat exchanger inlet  122 , for diverting a fluid flowing in the pipe into the heat exchanger interior compartment  118 , and a heat exchanger outlet  124  wherein the fluid exits the heat exchanger back into pipe  103 . The interior compartment  118  of the heat exchanger includes a closed heating line  121  for circulating a fluid heated to a temperature greater than the fluid flowing in the pipeline and diverted into the heat exchanger so that heat from the heated fluid may be thermally transferred to the diverted fluid, thereby raising its temperature. Because the heating line is closed, the heated fluid circulating therein does not come into contact with, i.e. does not mix with, the fluid diverted from the pipeline. The heated fluid enters the heating line at a heating line inlet  114  and exits the heating line through a heating line outlet  116 . The heating fluid may include propylene glycol, water, oil, or other suitable heating fluids. The heating fluid can be heated using any of a variety of known heating devices such as boilers, electric based heaters, hydronic heaters, or other suitable heating devices, which may be closed system heaters or open air heaters. The heating fluids heated thereby may be transported over heating lines of any convenient length, ranging anywhere from several inches to over one hundred feet, and are connected to heating line input and output  131 ,  132 , respectively. 
     The heating line input  114  penetrates a wall  119  of the heat exchanger  117  as does the heating line outlet  116 . In one embodiment, an overall configuration of the heating line  121  within the heat exchanger interior compartment  118  has a U shape, therefore, the heating line input  114  and output  116  penetrate a common wall of the heat exchanger proximate to each other. The heating line may be made from copper or other metal which, because of the heated fluid flowing through it, becomes heated to a temperature higher than the diverted fluid flowing through the interior compartment  118  of the heat exchanger  117 . The diverted fluid flowing through the interior compartment  118  of the heat exchanger  117  is heated by coming into physical contact with the surface of the heating line  121  while flowing through the heat exchanger. One example of a heat exchanger that may be used in the fluid heating system  100  is a straight tube heat exchanger made by Xylem, Inc. of Morton Grove, Ill. 
     As shown in  FIG. 2 , in one embodiment, the heat exchanger inlet  122  for connecting the pipe  103  and the heat exchanger  117  is a curved section of pipe  125  joined to a short extension of pipe from the heat exchanger using a pair of bolted flanges  134 . Also, in one embodiment, the heat exchanger outlet  124  includes a portion hollow square lower cross member  162 , a pipe section  129  between the lower cross member  162  and the pipe  103 , and shorter pipe sections connected by a pair of bolted flanges  133  between the heat exchanger  117  and the lower cross member  162 . Fluid exiting the heat exchanger  117  flows, as indicated by arrow  112 , from the heat exchanger through the pipe sections joined by bolted flange pair  133 , through the hollow square lower cross member  162 , through pipe section  129  and back into pipe  103  and flowing out of pipe  103  in the direction indicated by arrow  104 . 
     With reference to  FIG. 2 , a frame is used to support the pipe and heat exchanger that comprises the fluid heating system  100 . The frame allows the fluid heating system  100  to be transportable as a unit. A pair of longitudinal members  160  serves as a base for the framed transportable fluid heating system  200 . Lower cross members  161 ,  162 , are attached to the top surfaces of longitudinal members  160  near the ends of the longitudinal members, wherein one of the cross members  162  also serves as a portion of the heat exchanger outlet  124  as explained above. Four vertical members  163  are attached to the longitudinal members  160  at the ends of the longitudinal members  160  and extend vertically therefrom. The vertical members  163  are joined together in pairs by two upper cross members  164  attached to the upper ends of vertical members  160 . The two upper cross members are joined together by an upper longitudinal member  165 . At the upper surfaces of upper cross members  164  proximate to where the upper longitudinal member  165  is attached thereto, a loop is attached for use by a lifting means to lift the entire framed transportable fluid heating system  200  for transport. Such lifting means may include hook and cable assemblies typically employed by mechanical cranes for lifting heavy objects. 
     Unless otherwise specified herein, most of the pipe, heat exchanger, and frame assemblies described herein are made from a suitable grade of steel. The frame members as shown include rigid steel frame members having a square cross section as exemplary embodiments but are not limited to such embodiments. Moreover, the frame members may be attached in a variety of configurations sufficient to support and transport the fluid heating system described herein. As described herein, the term “attached” or “attaching” may refer to nut and bolt connections, braces, screws, and other suitable mechanical connection, and also may include welding, for example, arc welding components together such as frame members or supports for the pipe and the heat exchanger. In other instances, such as connecting pipe or pipeline sections together, bolted flanges are used for attaching these sections, as described above. 
     While the invention has been described with reference to particular 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 scope of the invention. 
     Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims. 
     While the invention has been described with reference to particular 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 scope of the invention. 
     Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims. 
     PARTS LIST 
     
         
           100  fluid heating system 
           101  fluid inlet 
           102  fluid flow direction 
           103  pipe 
           104  fluid flow direction 
           105  fluid outlet 
           106  valve 
           107  valve handle 
           108  non-diverted fluid flow 
           109  pipeline 
           110  diverted fluid flow 
           111  pipeline flange 
           112  returning fluid flow 
           114  heating line inlet fluid flow 
           116  heating line outlet fluid flow 
           117  heat exchanger 
           118  heat exchanger interior compartment 
           119  heat exchanger housing 
           120  pipe flange 
           121  heating line 
           122  heat exchanger inlet 
           124  heat exchanger outlet 
           125  curved pipe section 
           126  pipe flange 
           128  pipe flange 
           129  support pipe 
           130  support 
           131  heating line inlet 
           132  heating line outlet 
           133  bolted flange pair 
           134  bolted flange pair 
           160  longitudinal cross member 
           161  first lower cross member 
           162  second lower cross member 
           163  vertical member 
           164  upper cross member 
           165  upper longitudinal member 
           166  loop 
           200  transportable fluid heating system