Abstract:
Provided herein is a system for removing fluids, for example petroleum products, from a pipeline while providing a fluidic seal between the fluids contained within the pipeline and the external environment thereby preventing leaking or escape of hazardous gases. The provided system is versatile and be utilized with many valve configurations and pipeline systems. Further, the system may be used on any fluid in which the release of fumes or gases is a concern.

Description:
RELATED APPLICATIONS 
     This application claims benefit of priority to U.S. Provisional Patent Application No. 62/182,251 filed Jun. 19, 2016. 
    
    
     BACKGROUND 
     Various modalities exist for the efficient transportation of petroleum products, such as crude oil, gasoline, chemicals, and natural gas. Pipelines, rail cars, tankers ships, and trucks all work in harmony in the transportation network to deliver energy to the consumer. North America alone depends on over 185,000 miles of liquid petroleum pipelines, 320,000 miles of gas transmission lines, and more than 2 million miles of gas distribution pipelines. These pipelines constitute the dominant mode of petroleum product transportation. 
     Ideally, the pipeline is constantly transporting petroleum products with little or no downtime, but transportation may stop for maintenance or repair. Further, some pipelines are taken out of service when no longer needed. In these situations, it is sometimes necessary to remove the petroleum products from the pipeline. 
     One method for the removal of liquid petroleum from a pipeline is by pumping. This is problematic when the liquid diminishes to a level such that the pump mechanism begins to receive air or other gas causing cavitation. Various techniques are employed to prevent cavitation, for example, using a “pig” to flush the remaining petroleum through the pipeline and into the vacuum system. Pigs have significant drawbacks, however, because they are costly and time consuming to insert and remove from the pipeline. Another removal method is to insert a tube or pipe through a valve of the pipeline and attaching the vacuum system to the tube or pipe using a flexible tube. However, in order for the tube to fit through the valve and flange, the diameter of the tube must be less than the valve opening, which exposes the fluid within the pipeline to the environment, potentially allowing the escape of petroleum vapors into the atmosphere. Moreover, if the liquid within the pipeline is pressurized, then liquid may escape. 
     SUMMARY 
     It can be seen from the foregoing that there remains a need in the art providing for the safe and efficient removal of fluids from pipelines while protecting the environment from the release of hazardous materials. 
     The presently disclosed instrumentalities overcome the aforementioned problems and advance the art by providing a system for removing petroleum products from a pipeline. This includes use of a fluidic seal between the fluids contained within the pipeline and the external environment. The provided system is advantageously versatile and may be utilized with many valve configurations and pipeline systems. Further, the system may be used to prevent the release of any gas or liquid of concern. 
     In one embodiment, a tubular body is provided for removing a fluid from a pipeline. The tubular body has two ends, each of the ends having at least one opening in fluidic communication with a flow passage running longitudinally through the tubular body to allow the longitudinal flow of fluid through the tubular body. A plug is configured to fit in a valve or flange of the pipeline, the plug having an interior channel configured to allow the tubular body to pass through the plug and creating a fluidic compression seal between the interior channel and an outer surface of the tubular body. 
     According to one aspect, a portion of the valve or flange may be threaded and a portion of the plug is threaded to permit advancement of the plug within a nipple extension under conditions of isolating internal pressure of the pipeline from atmospheric pressure. 
     In one aspect, a first end of the tubular body may be configured for positioning substantially adjacent to an interior surface of the pipeline. The first end of the tubular body may be formed along a plane with an angle set perpendicularly with respect to a longitudinal axis of the tubular body. Alternatively, the plane is orthogonal to the longitudinal axis of the tubular body, such as an angle selected from the group consisting of: 20, 30, 40, 50, 60, 70 and 80 degrees. 
     In one aspect, the fluidic seal may utilize threads in combination with at least one of a press fit, welding, a gasket, an O-ring or combinations thereof. 
     According to one aspect, the tubular body may be a tube or a pipe. The tubular body may have, for example, at least four openings at a first end of the tubular body. Each opening may communicate with internal flow passages running longitudinally through the tubular body, such as four internal flow passages in the case of four openings. 
     According to one embodiment, a method is provided for use of the aforementioned system in removing liquid from a pipeline under a condition of isolating internal pipeline pressure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  provides a schematic of a drain system installed on a pipeline valve body. 
         FIG. 2  provides a schematic of an embodiment of a plug and insert or “stinger” for placing within the drain system. 
         FIG. 3  shows the drain system with the plug and stinger installed. 
         FIG. 4  a section view taken along line  4 ′- 4 ′ of  FIG. 3 ; 
         FIGS. 5A and 5B  show example embodiments of the flow passage and openings near the end of the tubular body or pipe.  FIG. 5A  provides single opening at the end of the insert with a flat opening.  FIG. 5B  provides an angled end with a single opening at the end of the tubular body or pipe; 
         FIG. 6  is a process diagram showing use of the drains system according to one embodiment; and 
         FIG. 7  shows the drain system according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The instrumentalities described below teach by way of example and not by limitation. Accordingly, the discussion should not be used in a manner that unduly limits the described invention. 
       FIG. 1  illustrates a pipeline drain valve arrangement for a pipeline  100 . A flange  102  and valve  104  (e.g. a ball valve) are in fluid communication with the pipeline  100  through a connection  106 . The connection  106  can be, for example, a weld between the flange  102  and the pipeline  100  achieved during a hot tapping operation. The flange  102  and valve  104  are orthogonal to the flow direction F of the pipeline  100 . A seat  108 , for example threads, is positioned on the inner diameter of the flange  102 . The seat  108  can be used to create seal between the flange  102  and an inserted plug, for example, a completion plug which can be installed to seal the flange by threading into the seat  108  and prohibiting the flow of fluids into the valve  102 . A completion plug, for example, may be inserted after a hot tapping operation is finished and may utilize the same device that drills into the pipeline during hot tapping to set the plug. Optionally, the seat  108  may be in the lower portion of the valve  104 . 
     In some embodiments, by way of example, the flange  102  may be welded to the pipeline  100  in preparation for a hot-tap operation. Flanges of this nature are known to the art. Internally, but not shown in  FIG. 1  is a tubular body, which may also be called a stinger and is capable of draining fluid from inside the pipeline  100 . The tubular body (not shown) reaches to the internal bottom of the pipeline  100  for substantially complete drainage thereof. The flange  102 , valve  104 , connector  106 , and seat  108  may have any dimension, but preferably have industry standard dimensions commonly in use. In many embodiments, for example, these may be standardized for two inch diameter couplings utilizing threads that are commonly employed for use in pipeline hot tap operations. Proper use and selection of these devices may be governed by governmental regulation and/or engineering design requirements that are well known to the art. 
     Fluid may be removed for repairs and maintenance through the flange  102  by opening valve  104 . A common method for the removal of oil in the prior art was to attach a vacuum hose directly to the outlet  110  of the valve  104 , open the valve  104  and apply suction to remove remaining hydrocarbons. As the fluid level in the pipeline  100  decreases, the vacuum system pulls gas (cavitates), and so the pipeline cannot be completely drained without use of the presently disclosed drain system  20 . 
       FIG. 2  shows one embodiment of the drain system  20 . A plug  200  includes a plug end  202 , an externally threaded plug body  204 , and an optional elastomer  206  (e.g. an O-ring or gasket). External threads of the externally threaded plug body  204  sealingly engage complimentary threaded seat  108  of the flange  102  (see  FIG. 1 ), forming a seal in which compression of the elastomer  206  slightly bulges the elastomer  206  to enhance the seal by forming a compression seal between the plug  200  and the internal diameter of flange  102  and/or seat  108 . 
     The plug  200  also creates an internal seal along the length of the insert  208  adjacent to the threaded end  202 , the plug body  204 , and the elastomer  206 . Thus, it will be appreciated that these first and second seals isolate an interior side I of drain system  20  from an exterior side E. Moreover, this isolation prevents gas or liquid from side I from crossing the drain system  20  to reach side E. If some leakage does occur, this may be prevented by further compression of elastomer  206  to enhance the integrity of the secondary seal between the plug  200  and the flange  102 . 
     The plug  200  is similar in size and shape to a completion plug, however the tubular body  208  allows for the flow of fluids into the valve  104 . The plug may be installed in a similar manner to that of a completion plug, for example using the T-101 Drilling Machine by T. D. Williams, as described in more detail below. The tubular body  208  may be referred to as a “stinger” because it forms a male member that enters into mating engagement with a complementary female through-receptacle or channel formed within the combined bodies of end  202 , externally threaded plug body  204  and elastomer  206 . The tubular body  208  and plug body  204  may be slidably engaged to permit relative motion between the two bodies, but the tubular body is preferably press-fit or welded in place. The length of tubular body  208  is preferably sufficient to reach the internal bottom of pipeline  100  (see  FIG. 3 ) for drainage purposes. The top of the tubular body  210  is in fluidic communication with another system, such as the valve  104  which may be connected leading to a pump inlet (not shown) or vacuum source at its outlet  110 . The tubular body  208  has an outside diameter that is approximately the same as the inside diameter of the plug  200 . The tubular body  208  allows for the removal of fluid from the pipeline  100  interior on side I of drain system  20  through its lower end  212  Optionally, tubular body  208  may include a plurality of continuous openings contained within the diameter of the pipe, for example 4, 6, 8, 10, 12 and so-on. 
       FIGS. 5A and 5B  illustrate alternative options for the end  212  of tubular body  208  and integral flow passages  500 ,  502  at end  212 . The respective flow passages  500 ,  502  are in fluidic communication with the pipeline interior at side I. While the version of end  512  shown in  FIG. 5A  is orthogonal to the axis of elongation in tubular body  208 .  FIG. 5B  provides an end of the pipe having an axial plane  504  that is at an oblique angle from the longitudinal axis  506  of the tubular body  208 . The oblique angle is, for example, at 20, 30, 40, 50, 60, 70, or 80 degrees from the longitudinal axis  506  provided as a dashed line in  FIG. 5B . 
       FIGS. 3 and 4  show the drain system  20  in different environments of use. While the drain system  20  may be used in combination with any pipeline valve, illustrated is a ball valve  104  with dashed lines representing the valve  104  internal passage. For example, as shown in  FIGS. 3 and 4 , the drain system  20  is threadably received in seat  108  of flange  102  in fluid communication with pipeline  100 . The drain system  20  separates ball valve  104  from the pipeline  100 . Thus, the ball valve  104  may be opened to drain the interior of pipeline  100  through the tubular body  208  through ball valve  104  and the plug  200  for more complete draining of liquids from within pipeline  100 . Thus, the drain system may be inserted into any flange or valve along the length of pipeline  100 , including added valves or sleeves, for example by use of a stopple. 
       FIG. 6  demonstrates a method  600  of using the drain system  20  according to one embodiment. The plug  22  is inserted  602  into a flange or valve of a pipeline, such as flange  60  or ball valve  62  associated with pipeline  62 , forming the second seal described above. The tubular body  36  may then be inserted  604  as a stinger into channel  42 , forming the first seal described above. It is then possible to drain  606  fluid from within the pipeline. Where the plug  22  is inserted into a valve, such as ball valve  19  in consequence of step  602 , the valve may be used to pressure-isolate the pipeline interior from atmosphere, such that it is possible to sting into a pressurized pipeline. 
     It will be appreciated that the drain system  20  is may be made of a unitary piece of metal or elastomer. For example, with plug end  202 , plug body,  204  and elastomer  206  may be made of a unitary construction formed as a single piece of metal or elastomer in low pressure applications where it is unnecessary to tighten plug ends for bulging of elastomer  206 . 
     Metals or other materials that do not corrode in petroleum products can be used in the manufacture the tubular body  208  and plug  200 . Such metals include steel (including carbon steel, Hastaloy, and stainless), aluminum, aluminum alloys, titanium, and combinations thereof. Non-metal materials include ceramic, carbon fibers, nylon, propylene, ethylene, and polyester. The tubular body  208  and plug  200  may also be a mixture of metals and non-metals. For example, the interior of the elongated pipe can comprise a metal, while the exterior of the pipe that is inserted through the valve and flange a non-metal. A non-metal exterior may help prevent cold welding of the tubular body to the plug in situations where the pipe and plug have the same diameter. 
       FIG. 7  shows an assembly view of the presently disclosed instrumentalities according to one embodiment. As shown in  FIG. 7 , a flange  102 , connector  106 , seat  108 , and valve  104  have been connected to pipeline in a hot-tap operation as is known to the art. A hot-tap drilling tool  700 , such as the T101 made by T D Williamson, permits drilling under a closed pressure system by use of the drilling tool  700  to penetrate and form an opening through the exterior wall of pipeline  100  beneath flange  102 . In this drilling operation, the tool  700  penetrates valve  104  in the open position and extends through seat  108  before drilling through pipeline  100 . The tool  700  may then be retracted to a position above valve  104 , and the valve  104  is then closed to isolate pressure inside the pipeline  100 . The tool  700  may then be unthreaded from valve  104 . This permits valve  104  to be coupled with a system (not shown), such as a vacuum system, to drain liquid from inside pipeline  100 . The valve  104  may be removed at this time, but a best practice is to keep the valve  104  in place in case pressure unexpectedly returns to spike within the pipeline  100 . It will be appreciated that the valve  104  is depicted as a ball valve, but may alternatively be a gate valve, such as sandwich valve as is known in the art. 
     Successive parts are then successively coupled upward from valve  104  utilizing threaded couplings to install exterior male threads  720  of extension nipple  716  within female internal threads  722  of valve  104 . Upper male threads  718  of extension nipple  716  are received within internal female threads  714  of bushing  710 , and internal female threads  712  of the bushing  710  connect with external male threads of the threaded plug end  202 . In the embodiment of  FIG. 7 , the plug end  204  has a square drive hole  708  for mating engagement with a square drive  706 , which forms part of the tool  700 . The plug end  204  also has internal female threads for receiving external male threads  704  of the tool  700 . A hex drive shaft  702  extends through tool  700  and is capable of turning the square drive  706  and plug body  204 . 
     Rotation of the hex drive  702  is capable of advancing the square drive  706  of tool  700  to a distance substantially below external threads  704 . Thus, the extension bushing  716  is also provided with female internal threads (not shown). The externally threaded plug body  204  may, consequently, be advanced through the extension nipple  716  until tubular body  208  reaches the internal bottom of pipeline  100 . As depicted, the length of tubular body  208  is not to scale, and in use is longer than is depicted in  FIG. 7 , such that the tubular body  208  is capable of performing this task. It follows that the extension nipple  716  and other parts of  FIG. 7  are, in use, of sufficient length to permit the tubular body  208  to reach the internal bottom of pipeline  100 . 
     Once the drain system is assembled as shown in ‘ FIG. 7  and torqued to design specification, valve  104  may be opened. Rotation of the hex drive  702  advances the externally threaded plug body  204  through the extension nipple  716  until the tubular body or stinger  208  reaches the internal bottom of pipeline  101 . The system is pressure sealed to prevent unwanted release of internal pipeline liquids in case there might be an unexpected internal pressure spike within pipeline  100 . If no such pressure spike exists, for example, as denoted on a pressure gage (not shown) on tool  700 , then the tool  700  may be removed and the internal female threads of plug end  204  connected to, a conventional vacuum system (not shown) for complete drainage of pipeline  100  at this location. 
     Those skilled in the art will, appreciate that what is shown and described may be subjected to insubstantial changed without departing from the true scope and spirit of invention. Accordingly, the inventors hereby state their intention to rely as needed upon the Doctrine of Equivalents in protecting their rights to the invention.