Patent Publication Number: US-11655929-B2

Title: Reducing the risk of corrosion in pipelines

Description:
CROSS REFERENCE 
     This disclosure and claims the benefit of priority to U.S. Provisional Patent Application No. 62/896,936, filed Sep. 6, 2019, and U.S. Provisional Patent Application No. 62/896,941, filed Sep. 6, 2019, the contents of both of which are incorporated by reference herein. 
    
    
     TECHNICAL FILED 
     This disclosure relates to constructing internally coated pipelines and other long sections of pipe. 
     BACKGROUND 
     Extended length fluid conduits, such as pipelines, are constructed from several individual tubulars. Each individual tubular is typically constructed of carbon steel materials. The internal (wetted) surfaces of each individual tubular are coated, if required, to mitigate corrosion concerns during operation. The internal coating is applied under controlled conditions within a fabrication shop, but the individual, coated tubulars are welded together in the field. The field welding causes damage to the factory applied coating at pipe end joints, so a new coat is added in the field once the weld is completed to ensure that none of the piping internals are left uncoated. Such an application is often performed by a robotic crawler operated by a field technician. This process is repeated for each individual tubular during field construction. 
     SUMMARY 
     This disclosure describes technologies relating to reducing the risk of corrosion in pipelines. 
     An example implementation of the subject matter described within this disclosure is a tubular with the following features. A carbon steel main body defines a flow passage. The carbon steel main body includes an end. The carbon steel main body includes a beveled edge at the end. A corrosion resistant cladding is deposited along an inner surface of the carbon steel main body. The corrosion resistant cladding extends from the end to a distance into the carbon steel main body. A galvanic protection system is configured to reduce galvanic corrosion between the carbon steel and the corrosion resistant cladding. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. An epoxy coating extends along an interior surface of the tubular. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The distance into the carbon steel main body that the corrosion resistant cladding extends is substantially four to seven inches. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The corrosion resistant cladding includes alloy 625. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. An inner surface of the corrosion resistant cladding smoothly transitions to the inner surface of the carbon steel main body. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The corrosion resistant cladding is deposited as a weld overlay. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The corrosion resistant cladding includes two layers of weld overlay. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The end is a first end. The corrosion resistant cladding is a first corrosion resistant cladding. The distance is a first distance. The carbon steel main body includes a second end. The tubular further includes a second corrosion resistant cladding deposited along the inner surface. The second corrosion resistant cladding extends from the second end to a second distance into the carbon steel main body. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The first distance and the second distance are substantially the same. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The carbon steel main body includes a beveled edge at the second end. 
     An example implementation of the subject matter described within this disclosure is a method of manufacturing a tubular. The method includes the following features. A carbon steel tubular body with an end is received. A corrosion resistant cladding is deposited along an inner surface of the tubular. The corrosion resistant cladding extends a distance along the inner surface from the end. An epoxy coating is deposited along the inner surface of the carbon steel tubular body and along an inner surface of the corrosion resistant cladding. Galvanic corrosion between the carbon steel and the corrosion resistant cladding is reduced by a galvanic protection system. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. Depositing the corrosion resistant cladding includes weld overlay. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The weld overlay includes two layers. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The corrosion resistant cladding includes alloy 625. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The end of the carbon steel tubular body is beveled. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The carbon steel tubular body is a first carbon steel tubular body. A second carbon steel tubular body, substantially identical to the first carbon steel tubular body, is received. A bevel is added to the end of the first carbon steel tubular body. A bevel is added to an end of the second carbon steel tubular body. The first carbon steel tubular is welded to the second carbon steel tubular at the bevel of the first carbon steel tubular and the bevel of the second carbon steel tubular. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. Welding the first carbon steel tubular to the second carbon steel tubular includes using a girth weld. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The girth weld is a full penetration weld. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The weld includes a second corrosion resistant alloy. 
     Aspects of the example implementation, which can be combined with the example implementation alone or in combination, include the following. The second corrosion resistant alloy is metallurgically compatible with the carbon steel and the corrosion resistant cladding. 
     An example implementation of the subject matter described within this disclosure is a pipeline with the following features. A first tubular includes a first carbon steel main body defining a first flow passage. The first carbon steel main body includes a first end. The first carbon steel main body includes a first beveled edge at the first end. A first corrosion resistant cladding is deposited along an inner surface of the first carbon steel main body. The first corrosion resistant cladding extends from the first end to a distance into the first carbon steel main body. An epoxy coating extends along an interior surface of the first tubular. A second tubular includes a second carbon steel main body defining a second flow passage being in-line with the first flow passage. The second carbon steel main body includes a second end. The second carbon steel main body includes a second beveled edge at the second end. A second corrosion resistant cladding is deposited along an inner surface of the second carbon steel main body. The second corrosion resistant cladding extends from the second end to a distance into the second carbon steel main body. An epoxy coating extends along an interior surface of the second tubular. The first tubular and the second tubular are connected by a weld at the first beveled edge and the second beveled edge. The weld includes a full penetration weld. A galvanic protection system is configured to reduce galvanic corrosion between the carbon steel and the corrosion resistant cladding in the first tubular and the second tubular. 
     An example implementation of the subject matter described within this disclosure is a pipeline with the following features. A first tubular and a second tubular welded in series. An interior surface of both the first tubular and the second tubular, proximal to the weld, includes a corrosion resistant alloy. 
     Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following advantages. The subject matter described herein, describes using corrosion resistant materials (weld overlay or solid piece of materials) at pipe ends to avoid application of field-applied internal coating. This solution results in major schedule reduction in the pipeline construction phase by avoiding coating appreciation, inspection, and possible reworks of field welds and coatings. 
     The details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a side-cross sectional view of an example pipeline. 
         FIG.  2    is a side-cross sectional view of an example seam of the example pipeline. 
         FIG.  3    is an example tubular arrangement that can be used with aspects of this disclosure. 
         FIG.  4    is a flowchart of a method of manufacturing a tubular that can be used with aspects of this disclosure. 
         FIG.  5    is a side-cross sectional view of an example pipeline. 
         FIG.  6    is an example tubular arrangement that can be used with aspects of this disclosure. 
         FIG.  7    is a flowchart of a method that can be used with aspects of this disclosure. 
     
    
    
     Like reference numbers and designations in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     For water injection or multiphase oil and gas pipelines, internal corrosion contributes to failures and leaks. The application of Field Joint Coating (FJC) to girth welds becomes a challenge due to difficulty of robotic crawler access especially for longer strings of pipes (hundreds of meters) or curved (non-straight) pipe configurations as the field welding progress is faster than the coating and curing operations. Another challenge of FJC is attributed to the limited number of coating service providers for straight pipes using robotic crawlers. Although rigorous field cleaning and coating inspections are conducted on the internally coated areas, the field coating quality is inferior to the factory applied coating as temperatures, humidity, and cleanliness cannot be as easily controlled in the field. This can result in coating thicknesses being outside of desired specifications, improper bonding to the weld, or a combination. 
     This disclosure describes a tubular arrangement for long fluid conduits, such as pipelines, that addresses these concerns. In general, this disclosure describes using a first tubular and a second tubular welded in series. An interior surface of both of the tubulars includes a corrosion resistant alloy near the welded connection. The corrosion resistant alloy resists corrosion without needing an application of FJC. 
     In some implementations, the corrosion resistant alloy is coated or cladded onto an interior surface of a main tubular near an end of the tubular to be welded.  FIG.  1    is a side cross-sectional view of an example pipeline  100  in accordance with some implementations of the present disclosure. As illustrated, the pipeline  100  includes a first tubular  102   a . The first tubular  102   a  includes a first carbon steel main body  104   a  that defines a flow passage  106 . The first carbon steel main body  104   a  includes a first end  108   a  with a first beveled edge  110   a . Near the first end  108   a , a corrosion resistant cladding  112   a  is deposited along an inner surface of the first carbon steel main body  104   a . The corrosion resistant cladding  112   a  extends from the first end  108   a  to a distance  114   a  into the first carbon steel main body  104   a.    
     A coating, such as a powder epoxy or liquid glass-flake coating material, coats an interior surface of the first tubular  102   a . The coating protects the interior (wetted) surface of the first tubular  102   a  from corrosion caused by a process fluid  116 . 
     A second tubular  102   b  is substantially similar to the first tubular  102   a . The second tubular includes a second carbon steel main body  104   b  that further defines the flow passage  106 . The second carbon steel main body  104   b  includes a second end  108   b  with a second beveled edge  110   b . A corrosion resistant cladding  112   b  is deposited along an inner surface of the second carbon steel main body  104   b  as well. The second corrosion resistant cladding  112   b  extends from the second end  108   b  to a distance  114   b  into the second carbon steel main body  104   b.    
     Similar to the first tubular, the second tubular is coated along its interior surface with an epoxy or glass-flake coating. The coating protects the interior (wetted) surface of the first tubular  102   a  from corrosion caused by a process fluid  116 . 
     The first tubular  102   a  and the second tubular  102   b  are connected by a weld  117  at the first beveled edge  110   a  and the second beveled edge  110   b . The weld  117  is a full penetration weld. That is, the weld extends an entire wall thickness of the tubular  102  such that a portion of the weld extends to the inner (wetted) surface of the tubular  102 . Such a weld is typically conducted during field installation. The weld can be deposited using manual (Shield Metal Arc Welding (SMAW) or Gas Tungsten Arc Welding (GTAW)) or automatic welding (Gas Metal Arc Welding (GMAW) or GTAW) processes. Other welding processes can be used without departing from this disclosure. 
       FIG.  2    is a side-cross sectional view of an example seam  200  of the example pipeline  100 . The seam  200  includes the full penetration weld  117 , such as a girth weld  202 . While a girth weld  202  is primarily mentioned and described within this disclosure, other types of welds can be used so long as the pressure and structural integrity of the completed pipeline  100  is intact. The girth weld  202  includes an alloy that is compatible with both the corrosion resistant cladding  112  and the carbon steel tubular body  104 . 
     As previously described, the cladding  112  extends from an end of each tubular  102  to a distance or length  114  within each tubular  102 . In some implementations, the distance  114  into each tubular is substantially the same (within standard manufacturing tolerances). In general, the cladding  112  extends a sufficient distance to clad the entire heat effected zone of the weld  202  (or  117 ), and adjacent base metal which are thermally affected, as that is where the most damage to the epoxy  204  is likely to occur during field welding. 
       FIG.  3    is an example tubular arrangement  300  that can be used with aspects of this disclosure. In some implementations, the corrosion resistant cladding  112  extends substantially four to seven inches (within manufacturing tolerances) into the carbon steel body. In some implementations, other lengths of cladding can be used. Criteria for the length of the cladding  112  are described throughout the disclosure. Several different corrosion resistant cladding options can be used, for example, alloy 625; however, different corrosion resistant claddings can be chosen based on the service of the pipeline. In some implementations, the corrosion resistant cladding  112  is deposited as a weld overlay using manual welding, automatic welding, or a combination. Multiple passes can be used to deposit several cladding layers with such a method, for example, two layers of overlay can be used. Other deposition methods can be used without departing from this disclosure. For example a single layer Electroslag Welding (ESW) technique can be used. In some implementations, the cladding is at least three millimeters thick. 
     To reduce friction loss, the interface between the epoxy coating  204  and the corrosion resistant cladding  112  should be smooth. That is, the inner surface of the corrosion resistant cladding  112  smoothly transitions to the inner surface of the epoxy  204  along the inner surface of the carbon steel main body  104 . That is, the interface between the coating  204  and the corrosion resistant cladding  112  should have few, if any, discontinuities that can create turbulence within the tubular  102 , which could lead to a coating failure. For example, the interface can include tapering angles in lieu of hard, right angles. The cladding can be at least three millimeters thick and tappers smooth to the adjacent base metal, for example, with a slope not steeper than 1:4, to avoid sharp edge at the end of cladding. After the cladding is applied, the coating materials are then applied in a controlled facility to extend at least partially over the cladding. The thickness of the coating layer can be as high as 750 microns of dry film epoxy coating or as high as 1000 microns of liquid glass-flake type coating. 
       FIG.  4    is a flowchart of a method  400  of manufacturing a tubular that can be used with aspects of this disclosure. At  402 , a carbon steel tubular body  104  is received. At  404 , a corrosion resistant cladding  112  is deposited along an inner surface of the carbon steel tubular body  104 . The corrosion resistant cladding  112  extends a distance  114  along the inner surface of the carbon steel tubular body  104  from the end of the carbon steel tubular body  104 . In some implementations, the corrosion resistant cladding  112  is deposited with a weld overlay. In some implementations, two layers of weld overlay can be used. In some implementations, the corrosion resistant cladding comprises alloy 625. At  406 , an epoxy coating is deposited along the inner surface of the carbon steel tubular body and the corrosion resistant cladding. The coating is partially applied over the cladding material as an overlap. For example, approximately a five inch gap (within manufacturing tolerances) from the end of the pipe can be left uncoated. 
     In some implementations, an end of the carbon steel tubular body can be beveled to accommodate a weld. Other types of welds with different preparation steps can be used without departing from this disclosure. In some implementations, a second carbon steel tubular body, substantially identical to the first carbon steel tubular body, can be received. A bevel can be added to an end of both the first carbon steel tubular body and the second carbon steel tubular body. The first carbon steel tubular can then be welded to the second carbon steel tubular at the bevel of the first carbon steel tubular and the bevel of the second carbon steel tubular. In some implementations, the weld can include a girth weld. In some implementations, the weld is a full penetration weld. In some implementations, the weld can include a corrosion resistant alloy, such as alloy 625. Regardless of the material used in the weld, the weld material is metallurgically compatible with the carbon steel and the corrosion resistant cladding. 
     In another implementation, a separate corrosion resistant tubular, such as a short pup, can be welded onto the end of a carbon steel tubular prior to field welding the tubulars together. That is, corrosion resistant alloys are attached at the ends of carbon steel double jointed pipeline which can be subsequently internally coated with epoxy under shop conditions. The corrosion resistant alloy pieced at each pipe end are welded first to carbon steel pipes. The pipe is then internally coated in the factory. The coating is applied over the weld and extends at least partially into the corrosion resistant alloy piece. The epoxy is aimed to enhance the flow characteristics of the production fluid traveling through the pipeline, and the epoxy protects an inner surface of the pipeline from corrosion. The corrosion resistant alloy piece is then welded in the field to adjacent corrosion resistant alloy mating materials using a compatible corrosion resistant alloy weld filler and process. 
       FIG.  5    is a side-cross sectional view of such an example pipeline  500 . As illustrated, the pipeline  500  includes a first tubular  502   a  with a first carbon steel main  504   a  body that defines a flow passage  506  through which process fluid  508  can flow. The first carbon steel main body  504   a  has a first end and a second end. The first carbon steel main body  504   a  includes a first beveled edge  510  at the first end. 
     A first corrosion resistant pup  512   a  further defines the flow passage  506 . The first corrosion resistant pup  512   a  has substantially the same inner diameter and outer diameter as the carbon steel main body  504   a  (within typical manufacturing tolerances). The first corrosion resistant pup includes a first end and a second end. The first corrosion resistant pup  512   a  has a first beveled edge  514  at the first end. The first corrosion resistant pup  512   a  is connected to the first carbon steel main body  504  by a dissimilar metal weld  516  along the beveled edge  510  of the first carbon steel main body  504   a  and the beveled edge  514  of the first corrosion resistant pup  512   a.    
     A second tubular  502   b  is substantially similar to the first tubular  502   a . The second tubular  502   b  includes a second carbon steel main body  504   b  and a second corrosion resistant pup  512   b . The second carbon steel main body  504   b  and the second corrosion resistant pup  512   b  further define the flow passage  106 . The second corrosion resistant pup  512   b  is connected to the first corrosion resistant pup  512   a  by a similar metal weld  518  along a second beveled edge  520  of the first corrosion resistant pup  512   a  and a similar beveled edge  522  of the second corrosion resistant pup  512   b . Each corrosion resistant pup  512  is substantially an equivalent length within standard manufacturing tolerances. 
     An epoxy coating  524  is distributed along an interior surface of the first tubular  502   a  and the second tubular  502   b . The epoxy coating  524  extends along an inner surface of each carbon steel main body  504 , each dissimilar metal weld  516 , and at least a portion of each corrosion resistant pup  512 . 
       FIG.  6    is an example tubular arrangement  600  that can be used with aspects of this disclosure. As illustrated, a carbon steel main body  504  defines a flow passage  506  ( FIG.  5   ). The carbon steel main body  504  includes a beveled edge  510  at the first end of the carbon steel main body  504 . A corrosion resistant pup  512  further defines the flow passage  506 . In some implementations, the corrosion resistant pup  512  includes alloy 625. While primarily described as including alloy 625, any weld-able, corrosion resistant alloy of sufficient strength can be used without departing from this disclosure. 
     The corrosion resistant pup  512  has the same wall thickness as the carbon steel main body  504  within standard manufacturing tolerances. The wall thickness of the specified main body is determined by the design and engineering office during the design phase based on the internal pressure, pipe diameter, and pipe strength. In all cases, the corrosion resistance piece  512  thickness and diameter shall be selected based on the predetermined wall thickness and diameter of the original carbon steel pipe. The strength of the alloy material  512  shall be selected to be equal or higher than the strength of the original carbon steel pipe. In general, the corrosion resistant pup  512  is long enough to fully contain a heat affected zone from a weld at both ends of the corrosion resistant pup  512  and to allow partial overlap coating. This length of pup piece is practically coated to allow conducting field welding without extending the heat to the factory coating. The overlap coating extends over the pup piece  512  such that substantially five inches (within manufacturing tolerances) of the corrosion resistant pup  512  remains uncoated toward the end of corrosion resistant pup  512  where weld is made. For example, in some implementations, the corrosion resistant pup  512  is substantially four to seven inches in length within standard manufacturing tolerances. In some implementations, other lengths can be used. Wall thickness, types of welds, and composition of the pup  512  and weld material can have an effect on the desired length of the corrosion resistant pup  512 . Similar to the cladding  112  of the previous implementation, each corrosion resistant pup  512  can be made of alloy 625 or another corrosion resistant material adequate for the intended service of the tubular. The corrosion resistant pup  512  includes a beveled edge  514  at one end. The corrosion resistant pup  512  is connected to the carbon steel main body  504  by a dissimilar metal weld  516  along the beveled edge  510  of the carbon steel main body  504  and the beveled edge  514  of the corrosion resistant pup  512 . 
     The dissimilar metal weld  516  connecting the corrosion resistant pup to the carbon steel main body is a full penetration weld. For example, a girth weld can be used. As the dissimilar metal weld  516  is a full penetration weld that may come into contact with an interior fluid flow, the weld can include a corrosion resistant alloy. In general, the weld alloy is metallurgically compatible with the carbon steel main body  504  and the corrosion resistant pup  512 . That is, the dissimilar metal weld  516  is able to fuse both metals to form a pressure tight seal and a structurally sound connection. 
     Each tubular includes an epoxy coating  524  along an interior surface of the tubular. The epoxy coating  524  is applied after the dissimilar metal weld is completed. The epoxy coating  524  covers an inner surface of the carbon steel body  504 , the dissimilar metal weld  516 , and at least a portion of the corrosion resistant pup  512 . The similar metal weld  518  between two corrosion resistant pups ( 512   a  and  512   b ) in the field does not need any field epoxy applied as the pups are made from corrosion resistant materials. 
       FIG.  7    is a flowchart of a method  700  of manufacturing a tubular that can be used with aspects of this disclosure. At  702 , a carbon steel tubular body  504  is received. The carbon steel tubular body  504  has an end. The end of the carbon steel tubular body  504  and an end of the corrosion resistant pup  512  are beveled prior to attaching the corrosion resistant pup  512  to the end of the carbon steel tubular  504 . 
     At  704 , a corrosion resistant pup  512  is attached to the end of the carbon steel tubular  504 . The beveled end of the carbon steel tubular body  504  is positioned to be adjacent to the beveled end of the corrosion resistant pup  512 . The beveled end of the carbon steel tubular body  504  is then welded to the beveled end of the corrosion resistant pup  512  with a full penetration weld, such as a girth weld  516 . 
     In some implementations, the corrosion resistant pup  512  includes alloy 625. In some implementations, other corrosion resistant materials can be used. The dissimilar metal weld  516  includes a corrosion resistant alloy as well since the weld  516  is a full penetration weld, and a portion of the weld  516  may be exposed to a wetted portion of the tubular. Regardless of the alloys used, the corrosion resistant alloy of the weld  516  is metallurgically compatible with the carbon steel tubular body and the corrosion resistant pup. That is, complete fusion occurs during the welding process to allow for a pressure-tight weld. The strength of the weld joint is substantially greater than or equal to the strength of the carbon steel tubular body. At  706 , an epoxy coating  524  is deposited along an inner surface of the carbon steel tubular body  504  and the corrosion resistant pup  512 . The epoxy coating  524  extends to cover the interior of the carbon steel tubular  504 , the full penetration weld  516 , and at least a portion of the corrosion resistant pup  512 . 
     After each tubular is constructed, they can be assembled in the field to create an extended tubular, such as a pipeline. In such an instance, a second tubular, constructed identically to any of the previously described tubulars, is received. The first tubular and the second tubular are attached end-to-end. More specifically, a corrosion resistant pup of the first tubular is attached to a corrosion resistant pup of the second tubular. Attaching the first corrosion resistant pup to the second corrosion resistant pup includes welding the first corrosion resistant pup to the second corrosion resistant pup. This particular weld  518  is a full penetration weld, such as a girth weld. The weld  518  includes a corrosion resistant alloy as well since the weld is a full penetration weld, and a portion of the weld is exposed to a wetted portion of the tubular. This penetrative portion of the weld  518  does not require a field application of epoxy as it includes a corrosion resistant alloy. 
     As dissimilar metals are adjacent to one another, there is the possibility of galvanic corrosion. The severity of such corrosion is dependent upon environmental factors and the electric potential between the carbon steel and corrosion resistant alloy. In some implementations, galvanic corrosion can be mitigated or reduced with a galvanic protection system  550 , such as a sacrificial anode or an impressed current catholic protection system. 
     While this disclosure contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular inventions. Certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. For example, a tubular with corrosion resistant cladding can be attached to a tubular with a corrosion resistant pup without departing from this disclosure. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described herein as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. 
     Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, the separation of various system components in the implementations described herein should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products. 
     Thus, particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results.