Abstract:
An arrangement of hydrocyclones, resulting in a greater density of hydrocyclones packaged in a given volume. One or more overflow extensions is secured to the overflow portions of one or more hydrocyclones to permit individual hydrocyclones to be placed into an axially staggered arrangement with respect to each other. By keeping the larger hydrocyclone heads from being directly adjacent that of a neighbor&#39;s, the maximum diameter of the hydrocyclones no longer becomes a limitation on the proximity of one hydrocyclone to another. The inlet section of one of a group of hydrocyclones is disposed to be adjacent either the separation portion of an adjacent hydrocyclone or an overflow extension, thereby permitting denser packaging. In another aspect, groups of axially staggered hydrocyclones are axially offset from and intermeshed with one another, permitting greater density in packaging. The groups of hydrocyclones are arranged into building blocks of three hydrocyclones each such that the axial ends of the individual hydrocyclones form a triangle, most preferably an equilateral triangle.

Description:
The present application claims the priority of U.S. Provisional Patent Application Ser. No. 60/374,922 filed Apr. 23, 2002. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates generally to an improved arrangement for packaging multiple hydrocyclone separators, especially those used for petroleum fluid processing. 
   2. Description of the Related Art 
   The overall construction and manner of operation of hydrocyclone separators is well known. A typical hydrocyclone includes an elongated tapered separation chamber or circular cross-section, which decreases in cross-sectional size from a large overflow and input end to an underflow end. An overflow or reject outlet for the lighter fraction is provided at the base of the conical chamber while the heavier underflow or accept fraction of the suspension exits through an axially arranged underflow outlet at the opposite end of the conical chamber. 
   Liquids and suspended particles are introduced into the chamber via one or more tangentially directed inlets. These are adjacent to the overflow end of the separation chamber to create a fluid vortex therein. The centrifugal forces created by this vortex throw denser fluids and particles in suspension outwardly toward the wall of the conical chamber, thus giving a concentration of denser fluids and particles adjacent thereto, while the less dense fluids are brought toward the center of the chamber. As the denser fluids and particles continue to spiral towards the small end of the conical chamber, the lighter fractions are forced to move by differential forces in the reverse direction towards the reject outlet. The lighter fractions are thus carried outwardly through the overflow outlet. The heavier particles continue to spiral along the interior wall of the hydrocyclone and eventually pass outwardly via the underflow outlet. 
   The fluid velocities within a hydrocyclone are high enough that the dynamic forces produced therein are sufficiently high to overcome the effect of any gravitational forces on the performance of the device. Hydrocyclones may therefore be arranged in various physical orientations without affecting performance. Hydrocyclones are commonly arranged in large banks of several dozen or even several hundred hydrocyclones with suitable intake, overflow, and underflow assemblies arranged for communication with the intake, overflow and underflow openings respectively of the hydrocyclones. 
   Earlier separator systems involving large numbers of hydrocyclone separators commonly employed complex systems of intake, overflow, and underflow pipes or conduits which occupied a substantial amount of space and which required costly and complex support structures for the piping systems involved. It is desired to reduce the space occupied by hydrocyclone assemblies and provide a relatively compact arrangement, especially in the petroleum industry, where offshore platform applications and ship-based installations put a premium on space. A compact arrangement would also minimize the cost of the equipment and improve flow distribution to the hydrocyclone inlets. 
   The inventor has realized that a related limitation of existing hydrocyclone assembly design is that of flow distribution of fluid into the individual hydrocyclones of an assembly where the hydrocyclones are disposed in parallel within a conventional hydrocyclone vessel. In this type of arrangement, exemplified in  FIG. 1 , the hydrocyclones  18  are all contained within a single vessel  12 . Fluid is injected into a chamber  28  of the vessel  12  via a single inlet nozzle  30 . As a result of differential pressure, the fluid passes from the chamber  28  into the inlets  31  of the individual hydrocyclones  18 . Using current designs, the inlets  31  of the individual hydrocyclones are all disposed at approximately the same longitudinal location within the chamber  28 . The concentration of fluid inlets  31  in the same location results in poor fluid distribution that may actually decrease the effectiveness of the hydrocyclone assembly  10  by limiting differential pressure in the area where the inlets  31  are concentrated. It would be desirable to provide improved flow distribution to the hydrocyclone inlets. 
   One variation of a prior art arrangement of hydrocyclones placed the hydrocyclones in vertically spaced apart layers, with the hydrocyclones of each layer being disposed in radial arranged arrays with common intake, overflow and underflow piping communicating with the hydrocyclones of the several layers. This arrangement saved the floor space area required for the hydrocyclones above the equipment floor while the intake, overflow and underflow piping was installed beneath the floor together with the necessary valves on each unit for adjusting pressures and for isolating individual hydrocyclones. 
   Alternative forms of modular hydrocyclone separator systems have been devised in an effort to overcome problems with the layered system. These new systems involve vertically disposed, suitably spaced intake, overflow and underflow headers. Individual hydrocyclones are connected to these headers and a positioned in generally vertical planes in substantially horizontal positions, one above the other. Thus, operator control of the system is facilitated and the operation of individual hydrocyclones can be observed. 
   Prior methods of arranging multiple hydrocyclones have provided only limited results in the goal of reducing the volume of space taken up by the hydrocyclones. U.S. Pat. No. 4,437,984 shows hydrocyclones arranged vertically, with the hydrocyclones parallel to each other. U.S. Pat. No. 4,163,719 shows hydrocyclones stacked in angled vertical arrays, where each hydrocyclone body is roughly parallel to other hydrocyclones in the same vertical array. U.S. Pat. No. 4,019,980 also shows hydrocyclones stacked in angled vertical arrays, where each hydrocyclone body is roughly parallel to other hydrocyclones in the same vertical array, and also shows multiple arrays sharing common input piping. U.S. Pat. No. 5,499,720 shows hydrocyclones arranged in a radial pattern, with the narrowing bodies of the hydrocyclones adjacent to each other. 
   It is desired to have hydrocyclones packaged as tightly together as possible so as to take up the minimum amount of space. For offshore platform and ship-based installations, volume of space is at a premium and greater efficiencies are desired for the use of a given volume of space. 
   Hydrocyclone separators are usually conical in shape, with a wide overflow end and a narrowed underflow end. Placing individual hydrocyclone separators parallel to each other requires that the distance between the center of any two hydrocyclones be at a minimum equal to the combined radii of the two hydrocyclones. Where the hydrocyclones may need to be removed for replacement or maintenance, additional spacing is required to allow for free movement of the hydrocyclones, or even for mounting elements. It is desired to reduce the amount of space between hydrocyclones to allow for more hydrocyclones to occupy a given space. 
   SUMMARY OF THE INVENTION 
   The present invention provides an improved arrangement of hydrocyclones, resulting in a greater density of hydrocyclones packaged in a given volume. One or more overflow extensions is secured to the overflow portions of one or more hydrocyclones to permit individual hydrocyclones to be placed into an axially staggered arrangement with respect to each other. By keeping the larger hydrocyclone heads from being directly adjacent that of a neighbor&#39;s, the maximum diameter of the hydrocyclones no longer becomes a limitation on the proximity of one hydrocyclone to another. In preferred embodiments described herein, the inlet section of one of a group of hydrocyclones is disposed to be adjacent either the separation portion of an adjacent hydrocyclone or an overflow extension, thereby permitting denser packaging and improved flow distribution. 
   In another aspect of the present invention, groups of axially staggered hydrocyclones are axially offset from and intermeshed with one another, permitting greater density in packaging. In a preferred embodiment, the groups of hydrocyclones are arranged into groups of three hydrocyclones each such that the axial ends of the individual hydrocyclones form a triangle, most preferably an equilateral triangle. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For detailed understanding of the invention, reference is made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings in which reference characters designate like or similar elements throughout the several figures of the drawings. 
       FIG. 1  is a side view of an exemplary prior art hydrocyclone assembly. 
       FIG. 2  is a side view of a currently preferred embodiment for a hydrocyclone assembly constructed in accordance with the present invention, showing three hydrocyclone separators. 
       FIG. 3  is a schematic end view of an exemplary layout for a packaging arrangement in accordance with the present invention showing three hydrocyclones that are axially staggered and axially offset. 
       FIGS. 4 and 5  are schematics depicting multiple triangular bundles of hydrocyclones being packaged to provide an intermeshed grouping of hydrocyclones. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A hydrocyclone separation assembly includes a plurality of individual hydrocyclones. Referring first to  FIG. 1 , an exemplary prior art hydrocyclone separation assembly  10  is shown that includes an outer cylindrical vessel  12  that retains a pair of support members, or plates,  14 ,  16 , proximate its axial ends that support several hydrocyclones  18  arranged in a substantially parallel relation with respect to one another. Opposite end portions of the hydrocyclones  18  are disposed through apertures  19  in the first and second support plates  14 ,  16 . 
   Each hydrocyclone  18  comprises a single tubular body with an overflow (reject) section  20 , an inlet section  22 , a tapered separation chamber section  24 , and an underflow (tail pipe) section  26 . As is known in the art, a fluid or fluid/solid mixture is introduced under pressure into a chamber  28  defined within the outer vessel  12  via a single inlet (shown schematically as nozzle  30 ). The inlet  30  is typically a large diameter inlet that is located proximate the longitudinal middle of the vessel  12  and delivers fluid flow that is at least equal to the individual capacity of the hydrocyclones  18  multiplied times the number of hydrocyclones  18 . The fluid mixture then enters the individual inlet sections  22  of each individual hydrocyclone  18  via lateral inlet ports  31 . The hydrocyclones  18  separate the fluid mixture into constituent fluid components in a well known manner. The lighter fraction of fluid exits the overflow outlet  20  of the hydrocyclone  12  and then exits the vessel  12  via reject nozzle  33 . The heavier fluid fraction exits each hydrocyclone  12  through the underflow section  26  and exits the vessel  12  via underflow nozzle  35 . 
   It is noted that the inlet section  22  of each hydrocyclone  18  includes a substantially cylindrical chamber portion  32 , which presents the largest cross-sectional diameter “D” of any portion of the hydrocyclone  18 . In the prior assembly  10  depicted in  FIG. 1 , the inlet sections  22  of neighboring hydrocyclones  18  are positioned directly adjacent to one another such that the axial ends  34  of the underflow section  26  of each hydrocyclone  18  are substantially aligned in a plane  36  that is normal to the longitudinal axes of the hydrocyclones  18 . As a result of this positioning, it can be seen that minimum spacing between the hydrocyclones  18  is constrained by the diameter D of the inlet section  22 . A trunnion  38  is fixedly secured to the radial exterior of the underflow section  26  of each hydrocyclone  18 . The trunnions  38  provide an interference fit within the support plate  16 . 
   Referring now to  FIG. 2 , there is shown a portion of an exemplary hydrocyclone separator assembly  50  that is constructed in accordance with the present invention. A set of three hydrocyclones  18   a ,  18   b , and  18   c  are depicted, although it should be understood that in practice there is typically a greater number of hydrocyclones  18 . The hydrocyclones  18   a ,  18   b , and  18   c  are constructed in essentially the same manner as the hydrocyclones  18  described earlier. The second hydrocyclone  18   b  is provided with an overflow extension  40  that extends between and interconnects the inlet portion  22   b  with the support plate  14 . The third hydrocyclone  18   c  is also provided with an overflow extension  42  that extends between and interconnects the inlet portion  22   c  with the support plate  14 . The overflow extension  42  has a length that is greater than the length of the overflow extension  40 . Both the overflow extensions  40  and  42  are tubular members that permit fluid to flow from the overflow outlet  20  through the support member  14  and into an overflow receptacle (not shown) of a type known in the art. It is also noted that the overflow extensions  40  and  42  each have a diameter “d” that is less than the diameter D of the inlet section and preferably approximates the smaller diameter “d” of a portion of a separation section  26 . The underflow sections  26   a ,  26   b , and  26   c  are provided with slidable trunnions  44  that are moveable axially along the length of the underflow sections  26   a ,  26   b , and  26   c . The trunnions  44  form a secure interference fit with the support plate  16 . 
   The axially staggered arrangement of the present invention has the effect of axially displacing the respective inlet sections  22   a ,  22   b , and  22   c  of the hydrocyclones  18   a ,  18   b , and  18   c  with respect to one another so that the inlet section of one hydrocyclone lies adjacent the separation chamber section  24   a ,  24   b ,  24   c  of a neighboring hydrocyclone. Specifically, the inlet section  22   c  of the third hydrocyclone  18   c  lies adjacent the separation chamber section  24   b  of the second hydrocyclone  18   b , while the inlet section  22   b  of the second hydrocyclone  18   b  lies adjacent the separation chamber section  24   a  of the hydrocyclone  24   a . It should be understood that the packaging techniques and methods of the present invention may be applied to any model of hydrocyclone having an inlet/head section which is greater in diameter than the underflow portion. Examples include “K” hydrocyclone liners having a removable involute, as well as those hydrocyclone liner styles known within the industry as “Km,” “Kq,” and “Gm.” 
   Additionally, the presence of the overflow extensions  40 ,  42 , and their reduced diameter (as compared to the inlet sections  22 ) accommodates neighboring inlet sections  22 . It can be seen from  FIG. 2  that the inlet section  22   a  of the hydrocyclone  18   a  lies adjacent the overflow exntension  40 , and the inlet section  22   b  of the hydrocyclone  18   b  lies adjacent the overflow extension  42 . It is noted that, in this axially staggered packaging arrangement, the axial ends  34  of the underflow sections  26   a ,  26   b , and  26   c  do not lie in a plane that is normal to the axes of the hydrocyclones  18 , such as plane  36  depicted previously. Instead, the ends  34  are staggered. 
   The axially staggered arrangement also provides improved flow distribution within the vessel  12  of the hydrocyclone assembly  10 . The fluid inlets  31  of the hydrocyclones  18   a ,  18   b ,  18   c  are axially spaced apart from one another, resulting in a higher effective differential pressure for each of the inlets  31 . As a result, flow distribution within the vessel  12  is improved. 
   It is preferred that the packaging of the hydrocyclones  18   a ,  18   b , and  18   c  be such that the inlet sections  22   a ,  22   b , and  22   c  be in contact with or in very close proximity to the respective adjacent separation chamber section  24  or overflow extension  40  or  42 . The hydrocyclones  18   a ,  18   b , and  18   c  may be aligned in a straight line, as  FIG. 2  depicts. Alternatively, the hydrocyclones  18   a ,  18   b , and  18   c  may be displaced in a second direction (Z axis) to result in a further space savings as is described with respect to FIG.  3 . 
   Referring now to  FIG. 3 , there is shown a schematic end-on view of three hydrocyclones  18   a ,  18   b , and  18   c  that are packaged in an arrangement wherein the three hydrocyclones are axially staggered, as described earlier with respect to  FIG. 2 , and further axially offset from one another. As used herein, the term “axially offset” means that the axes of the hydrocyclones  18   a ,  18   b , and  18   c  do not form a straight line and, instead, form a triangle, most preferably the equilateral triangle  46  depicted in FIG.  3 . The letter “S,” to denote a “short” length, is used to label hydrocyclone  18   a , indicating that the overall length of that hydrocyclone is less than the length of the hydrocyclones  18   b  and  18   c  when considered with their attached overflow extensions  40 ,  42 , respectively. The letters “M” denoting “medium” length and “L” denoting “long” length are used to label the hydrocyclones  18   b  and  18   c , respectively. 
   In the preferred embodiment depicted in  FIG. 3 , the packaging is such that the outer diametrical surface of the inlet section  22   a  of the first hydrocyclone  18   a  contacts or is closely proximate to the overflow extension  40  associated with the second hydrocyclone  18   b  and the overflow extension  42  associated with the third hydrocyclone  18   c . The outer diametrical surface of the inlet section  22   b  of the second hydrocyclone  18   b  contacts or is closely proximate to the separation chamber portion  24   a  of the first hydrocyclone  18 a as well as the overflow extension  42  associated with the third hydrocyclone  18   c . The outer diametrical surface of the inlet portion  22   c  of the third hydrocyclone  18   c  contacts or is closely proximate to the separation sections  24   a  and  24   b  of the first and second hydrocyclones  18   a  and  18   b , respectively. The three hydrocyclones  18   a ,  18   b ,  18   c  are preferably maintained together into the triangular configuration shown in  FIG. 3  by corresponding patterns of apertures  19  within the first and second support plates  14 ,  16 . In other words, the apertures  19  are disposed in a triangular configuration within the respective support plates  14 ,  16  and are of such spacing from one another that they retain the hydrocyclones  18   a ,  18   b , and  18   c  in the configuration depicted in FIG.  3 . The triangular formation depicted in  FIG. 3  results in a triangular bundle, generally indicated as  48 , in which the hydrocyclones  18   a ,  18   b ,  18   c  are intermeshed with one another to reduce the interstitial space between the hydrocyclones, thereby further enhancing the ability to package the hydrocyclones  18   a ,  18   b ,  18   c  densely within an assembly. 
   The triangular bundle  48  provides a basic building block that may be repeated within an assembly in order to maximize packaging of hydrocylones within a given volume or area.  FIGS. 4 and 5  illustrate this. The exemplary hydrocyclone bundle  48  described above is packaged with other, like-constructed bundles  50 ,  52 ,  54 ,  56 , and  58 . The spacing between the bundles  48 ,  50 ,  52 ,  54 ,  56 , and  58  is exaggerated in  FIG. 4  for clarity. It should be understood that, in fact, these bundles are all placed either into contact with or in very close proximity to one another, as indicated that the arrows  60 . The neighboring bundles can then be intermeshed with one another in the same manner as the individual hydrocyclones  18   a ,  18   b , and  18   c  are. In other words, the “S” hydrocyclone  18 a from the bundle  48  intermeshes with the axially staggered “M” hydrocyclone  18   b  from bundle  52  and “L” hydrocyclone  18   c  from bundles  50 . It can be appreciated, then, that the advantages of the present invention may be realized in a three-dimensional manner. Where the advantages of axially staggering hydrocyclones is clearly shown in a two-dimensional array in  FIGS. 2 ,  3  and  4  show that a greater density of hydrocyclones may also be achieved by implementing an axially offset relationship along a third dimension. 
   Those of skill in the art will recognize that numerous modifications and changes may be made to the exemplary designs and embodiments described herein and that the invention is limited only by the claims that follow and any equivalents thereof.