Abstract:
An oil well pumping apparatus for pumping oil from a well to a wellhead provides a tool body that is sized and shaped to be lowered into the production tubing string of the oil well. A working fluid is provided that can be pumped into the production tubing. A prime mover is provided for pumping the working fluid. A flow channel into the well bore enables the working fluid to be circulated from the prime mover via the production tubing to the tool body at a location in the well and then back to the wellhead area. A pumping mechanism is provided on the tool body, the pumping mechanism including first and second gerotors. The first gerotor is driven by the working fluid. The second gerotor is rotated by the first gerotor. The two gerotors are connected with a common shaft. The tool body has flow conveying portions that mix the working fluid and the produced oil as the oil is pumped. The pumping mechanism transmits the commingled fluid of oil and working fluid to the wellhead area where they are separated and the working fluid recycled.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not applicable  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable  
       REFERENCE TO A “MICROFICHE APPENDIX” 
       [0003]     Not applicable  
       BACKGROUND OF THE INVENTION  
       [0004]     1. Field of the Invention  
         [0005]     The present invention relates to oil well pumps. More particularly, the present invention relates to a downhole oil well pump apparatus that uses a circulating working fluid to drive a specially configured pump that is operated by the working fluid and wherein the pump transmits oil from the well to the surface by commingling the pumped oil with the working fluid, oil and the working fluid being separated at the wellhead or earth&#39;s surface. Even more particularly, the present invention relates to an oil well pump that is operated in a downhole cased, production pipe environment that utilizes a pump having a single pump shaft that has gerotor devices at each end of the pump shaft, one of the gerotor devices being driven by the working fluid, the other gerotor device pumping the oil to be retrieved.  
         [0006]     2. General Background of the Invention  
         [0007]     In the pumping of oil from wells, various types of pumps are utilized, the most common of which is a surface mounted pump that reciprocates between lower and upper positions. Examples include the common oil well pumpjack, and the Ajusta® pump. Such pumps reciprocate sucker rods that are in the well and extend to the level of producing formation. One of the problems with pumps is the maintenance and repair that must be performed from time to time.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     The present invention provides an improved pumping system from pumping oil from a well that provides a downhole pump apparatus that is operated with a working fluid that operates a specially configured pumping arrangement that includes a common shaft. One end portion of the shaft is a gerotor that is driven by the working fluid. The other end portion of the shaft has a gerotor that pumps oil from the well. In this arrangement, both the oil being pumped and the working fluid commingle as they are transmitted to the surface. A separator is used at the earth&#39;s surface to separate the working fluid (for example, water) and the oil. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:  
         [0010]      FIGS. 1A, 1B ,  1 C are a sectional elevation view of the preferred embodiment of the apparatus of the present invention, wherein the drawing  1 A matches to the drawing  1 B at match lines A-A and the drawing  1 B matches to the drawing  1 C at match lines B-B;  
         [0011]      FIG. 2  is a partial exploded perspective body of the preferred embodiment of the apparatus of the present invention showing some of the pumping components;  
         [0012]      FIG. 3  is an enlarged fragmentary sectional view of the preferred embodiment of the apparatus of the present invention illustrating the pumping components;  
         [0013]      FIG. 4  is a sectional view taken along lines  4 - 4  of  FIG. 3 ;  
         [0014]      FIG. 5  is a sectional view taken along lines  5 - 5  of  FIG. 3 ;  
         [0015]      FIG. 6  is a section view taken along lines  6 - 6  of  FIG. 3 ;  
         [0016]      FIGS. 7A-7B  are perspective views of the preferred embodiment of the apparatus of the present invention wherein the match line AA of  FIG. 7A  matches the match line AA of  7 B;  
         [0017]      FIG. 8  is a fragmentary, top view of the preferred embodiment of the apparatus of the present invention illustrating one of the filtered disks;  
         [0018]      FIG. 9  is a fragmentary plan view of the preferred embodiment of the apparatus of the present invention illustrating a filter disk spacer;  
         [0019]      FIGS. 10A-10E  are sequential illustrations that show various positions of the gerotor devices for both the upper and lower gerotors;  
         [0020]      FIG. 11A  is a schematic diagram showing operation of the apparatus and method of the present invention in a pumping position;  
         [0021]      FIG. 11B  is a schematic diagram showing operation of the apparatus and method of the present invention in a retrieval position; and  
         [0022]      FIG. 11C  is a schematic diagram showing operation of the apparatus and method of the present invention in a neutral position 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     Oil well pump apparatus  10  as shown in the sectional elevation view of  FIGS. 1A, 1B  and  1 C are in the lines A-A in  FIGS. 1A and 1B  are match lines and the lines B-B in  FIGS. 1B and 1C  are match lines. Oil well pump  10  is to be used in a well casing  11  that surrounds production tubing  12 . A packer  13  is set in between casing  11  and production tubing  12  as shown in  FIG. 1C . Landing nipple  14  is positioned above packer  13 . The landing nipple  14  receives the lower end portion  17  of tool body  15  as shown in  FIG. 1C . Tool body  15  can be pumped hydraulically ( FIG. 11A ) or lowered into the production tubing  12  bore  18  using a work string (not shown) that grips neck portion  32  at tool body  15  upper end  16 .  
         [0024]     The apparatus  10  of the present invention provides an oil well pump  10  that has a tool body  15  that is elongated to fit inside of the bore  18  of production tubing  12  as shown in  FIGS. 1A-1C . A well annulus  19  is that space in between casing  11  and production tubing  12 . During use, a working fluid such as water, “lease” water, or an oil water mixture can be used to power pump mechanism  26 . This working fluid follows the path that is generally designated by the arrows  20 ,  21 ,  22  and  23  in  FIGS. 1A-1B . The working fluid is pumped from the wellhead area  120  using a prime mover  121  as shown in  FIG. 11A  and indicated by arrows  20 .  
         [0025]     Prime mover  121  can be a commercially available pump that receives working fluid via flowline  122  from reservoir  123 . Reservoir  123  is supplied with the working fluid such as water via flowline  124  that exits oil/water separator  125 .  
         [0026]     As the working fluid is pumped by prime mover  121  in the direction of arrows  20  through production tubing  12 , the working fluid enters tee-shaped passage  34  as indicated by arrows  21 . The working fluid then travels in sleeve bore  36  of sleeve  35  as indicated by arrows  22  until it reaches connector  60  and its flow passages  67 . Arrows  23  indicate the flow of the working fluid from the passages  67  to retainer  111  and its passageways  112 ,  113 . At this point, the working fluid enters pump mechanism  26  (see  FIGS. 1B, 2 , and  3 - 6 ). A check valve  25  is provided that prevents oil from flowing in a reverse direction. This check valve  25  has a spring  50  that is overcome by the pressure of working fluid that flows through passageway  51  in the direction of arrows  20 ,  21 ,  22 ,  23 . The working fluid exits tool body  15  via passageway  137  and working fluid discharge port  65  (see arrow  24 ).  
         [0027]     The pump mechanism  26  is driven by the working fluid. The pump mechanism  26  also pumps oil from the well in the direction of oil flow arrows  27  as shown in  FIGS. 1B, 1C  and  11 A. Connector  68  attaches to the lower end of pump mechanism housing  63 . Connector  68  provides upper and lower external threads  69 ,  70  and flow passages  71  that enable oil to be produced to reach lower filter  31 , suction ports  133 ,  134  of retainer  132  and lower gerotor device  151  so that the oil can be pumped by lower gerotor device  151  via passageway  135  to produced oil discharge port  66 . At discharge port  66 , the produced oil enters production tubing bore  18  where it commingles with the working fluid, the commingled mixture flowing into annulus  19  via perforations  114 .  
         [0028]     Oil that flows from the producing formation in to the tool body (see arrows  27 ) flows upwardly via bore  86  of seating nipple  14 . The lower end portion  17  of tool body  15  has a tapered section  84  that is shaped to fit seating nipple  14  as seen in  FIG. 1C . An o-ring  87  on lower end  17  of tool body  15  forms a fluid seal between tool body  15  and seating nipple  14 . Above passageway  86 , oil is filtered with lower filter  31 . Of similar construction to filter  30 , filter  31  can be of alternating disks  76  and spacers  108  ( FIGS. 8-9 ). Filter disk  76  are secured to connector  68  with shaft  72  having threaded connection  73  attaching to connector  68  while retainer plate  74  and bolt  75  hold filter disks  76  to shaft  72  (see  FIG. 1B, 7B  and  8 - 9 ). Connector  68  attaches to pump mechanism body  3  at threaded connection  78 . Connector  68  attaches to sleeve  80  and its internal threads  82  at threaded connection  79 . Sleeve  80  has bore  81  occupied by lower filter  31  (see  FIGS. 1B and 7B ). Seating nipple  14  attaches to the lower end of sleeve  80  with threaded connection  83 . Seating nipple  14  has bore  86  and external threads  85  that connect to sleeve  80  at threaded connection  83 .  
         [0029]     Check valve  88  and its spring  89  prevent the working fluid from flowing into the formation that contains oil. The oil producing formation is below packer  13  and check valve  88 . The producing oil enters the production tubing bore  18  via perforations (not shown) as is known in the art for oil wells. The check valve  88  is overcome by the pump  26  pressure as oil is pumped upwardly in the direction of arrows  27 . The pump  26  includes two central impellers or rotors  94 ,  95 . The upper central rotor  94  and outer rotor  98  are driven by the working fluid. The lower central rotor  95  and outer rotor  99  are connected to the upper rotor  94  with shaft  91  so that the lower central rotor  95  rotates when the upper rotor  95  is driven by the working fluid. Thus, driving the upper rotor  94  with the working fluid simultaneously drives the lower rotor  95  so that it pumps oil from the well production bore  18 . The oil that is pumped mixes with the working fluid at perforations  114  in the production tubing as indicated schematically by the arrows  28 ,  29  in  FIGS. 1A, 1B . The arrows  29  indicate the return of the oil/water mix in the annulus  19  that is in between casing  11  and production tubing  12 .  
         [0030]     In  FIG. 11A , the oil, water (or other working fluid) mix is collected in flowline  126  and flows into oil/water separator  125  as indicated by arrows  127 . Oil is then removed from the separator in flowline  128  as indicated by arrows  129  in  FIG. 11A . The working fluid (e.g., water) is separated and flows via flowline  124  back into reservoir  123  for reuse as the working fluid.  
         [0031]     As an alternate means to lower the tool body  15  into the well (if not using pumping of  FIG. 11A ), a neck section  32  is provided having an annular shoulder  33 . This is common type of connector that is known in the oil field for lowering down hole tools into a well bore or as an alternate means of retrieval.  
         [0032]     An upper filter  30  is provided for filtering the working fluid before it enters the pump mechanism  26 . A lower filter  31  is provided for filtering oil before it enters the pump mechanism  26 .  
         [0033]     The tool body  15  includes a sleeve  35  that can be attached with a threaded connection  38  to the lower end portion of neck section  32  as shown in  FIG. 1A . A pair of swab cups  37 ,  40  are attached to sleeve section  35  at spacer sleeve  42 . The swab cup  37  provides an annular socket  39 . The swab cup  40  provides an annular socket  41 . The spacer sleeve  42  has a bore  43  that has an internal diameter that closely conforms to the outer surface of sleeve  35 . The sleeve  35  provides bore  36  through which working fluid can flow as shown in  FIGS. 1A and 1B . A third swab cup  44  is positioned just above valve housing  48  as shown in  FIG. 1B . The swab cup  44  has an annular socket  47 . A spacer sleeve  45  with bore  46  is sized to closely fit over sleeve  35  as shown in  FIG. 1B .  
         [0034]     Valve housing  48  has external threads that enable a threaded connection  49  to be formed with sleeve  52  at its bore  53  that is provided with internally threaded portions. The bore  53  of sleeve  52  carries filter  30  which is preferably in the form of a plurality of filter disks  54  separated by spacers  108  (see FIGS.  1 B,  8 - 9 ). As shown in  7 A, the filtered disks  54  of filter  30  are held in position upon shaft  57  with retainer plate  55  and bolt  56 . Shaft  57  has an internally threaded portion  58  for receiving bolt  56  as shown in  FIGS. 1B and 7A . A threaded connection  59  is formed between the lower end portion of shaft  57  and connector  60 . The connector  60  has externally threaded portion  61 ,  62  and a plurality of longitudinally extending flow passages  71  as shown in  FIG. 1B and 7A .  
         [0035]     The pump mechanism  26  (see  FIGS. 1B, 2 ,  3 ) includes a pump housing  63  that is attached using a threaded connection to the bottom of connector  60  at thread  62 . The pump housing  63  in  FIG. 7B  has internal threads  64  that enable connection with connector  60 .  
         [0036]     The housing  63  has a working fluid discharge port  65  and an oil discharge port  66  (see  FIG. 3 ). Pump housing  63  carries shaft  91 . The shaft  91  (see  FIGS. 2 and 3 ) has keyed end portions  92 ,  93 . Each rotor  94 ,  95  is provided with a correspondingly shaped opening so that it fits tightly to a keyed end portion  92  or  93  of shaft  91 .. In  FIG. 2 , the upper rotor  94  has a shaped opening  96  that fits the keyed end portion  92  of shaft  91 . The rotor  95  has a shaped opening  97  that fits the keyed end portion  93  of shaft  91 .  
         [0037]     Each of the central rotors  94 ,  95  fits an outer rotor that has a star shaped chamber. In  FIGS. 2 and 3 , upper rotor  94  fits the star shaped chamber  109  of rotor  98 . Similarly, the lower rotor  95  fits the star shaped chamber  110  of rotor  99 .  
         [0038]     Each rotor  94 ,  95  has multiple lobes (e.g., four as shown). The upper rotor  94  has lobes or gear teeth  100 ,  101 ,  102 ,  103 . The lower rotor  95  has floor or gear teeth lobes  104 ,  105 ,  106 ,  107 . This configuration of a star shaped inner or central rotor rotating in a star shaped chamber of an outer rotor having one more lobe than the central or inner rotor is a per se known pumping device known as a “gerotor”. Gerotor pumps are disclosed, for example, in U.S. Pat. Nos. 3,273,501; 4,193,746, 4,540,347; 4,986,739; and 6,113,360 each hereby incorporated herein by reference.  
         [0039]     Working fluid that flows downwardly in the direction of arrow  23  enters the enlarged chamber  113  part of passageway  112  of retainer  111  so that the working fluid can enter any part of the star shaped chamber  109  of upper disk  98 . An influent plate  115  is supported above upper disk  98  and provides a shaped opening  116 . When the working fluid is pumped from enlarged section  113  into the star shaped chamber  109  that is occupied by upper rotor  94 , both rotors  94  and  98  rotate as shown in  FIGS. 10A-10E  to provide an upper gerotor device  150 .  FIGS. 10A-10E  show a sequence of operation during pumping of the upper central rotor  94  in relation to upper outer rotor  98  and its star shaped chamber  109 . In  FIG. 10A , the opening  116  is shown in position relative to rotors  94  and  98 . The two reference dots  140 ,  141  are aligned in the starting position of  FIG. 10A . Arrow  118  indicates the direction of rotation of rotor  94 . Arrow  119  indicates the direct of rotation of upper disk  98 . By inspecting the position of the reference dots  140 ,  141  in each of the views  10 A- 10 E, the pumping sequence can be observed.  
         [0040]     The two gerotor devices  150 ,  151  provided at the keyed end portions  92 ,  93  of shaft  91  each utilize an inner and outer rotors. At shaft upper end  92 , upper inner rotor  94  is mounted in star shaped chamber  109  of peripheral rotor  98 . As the inner, central rotor  94  rotates, the outer rotor  98  also rotates, both being driven by the working fluid that is pumped under pressure to this upper gerotor  150 .  
         [0041]     The rotor or impeller  94  rotates shaft  92  and lower inner rotor or impeller  95 . As rotor  95  rotates with shaft  92 , outer peripheral rotor  99  also rotates, pulling oil upwardly in the direction of arrows  27 . Each inner, central rotor  94 ,  95  has one less tooth or lobe than its associated outer rotor  98 ,  99  respectively as shown in  FIGS. 2 and 10 A- 10 E. While  FIGS. 10A-10E  show upper rotors  94 ,  98 , the same configuration of  FIGS. 10A-10E  applies for lower rotors  95 ,  99 . An eccentric relationship is established by the parallel but nonconcentric axes of rotation of rotors  94 ,  98  so that full tooth or lobe engagement between rotors  94 ,  98  occurs at a single point only (see  FIGS. 10A-10E ).  
         [0042]     As working fluid flows through passageways  112 ,  113  into star shaped chamber  109  and shaped opening  116 , rotors  94 ,  98  rotate as do rotors  95 ,  99 . Oil to be produced is drawn through suction ports  133 ,  134  of retainer  132  to shaped opening  136  of effluent plate  117  and then into star shaped chamber  110  of outer rotor  99 . The rotating rotors  95 ,  99  transmit the oil to be pumped via passageway  135  to oil discharge port  66 .  
         [0043]     At discharge port  66 , oil to be produced mixes with the working fluid and exits perforations  114  in production tub  12  as indicated by arrows  28  in  FIG. 1B .  
         [0044]     In the pumping mode of  FIG. 11A , working fluid (e.g., water) moves from the reservoir  123  to the prime mover  121 . The prime mover  121  can be a positive displacement pump that pumps the working fluid through three way valve  130 . In the pumping mode, three way valve  130  handle  131  is in the down position as shown in  FIG. 11A , allowing the working fluid or power fluid into the tubing  12 . The working fluid pumps the tool body  15  into the seating nipple  14  and then the lower swab cups  40 ,  44  flare outwardly sealing against the tubing  12  causing the power fluid to then enter the ports or channel  34  at the upper end  16  of the tool body  15 . The working fluid travels through the center of the stacked disk upper filter  30  into the uppermost gerotor motor  150  causing the upper gerotor  150  to rotate and, in turn, causing the shaft  92  to rotate which causes the lower gerotor  151  to turn.  
         [0045]     When the lower gerotor  151  turns, it pumps produced oil into the casing annulus  19  so that it commingles (arrows  28 ) with the working fluid and returns to the surface. At the surface or wellhead  120 , the oil/water separator  125  separates produced oil into a selected storage tank and recirculates the power fluid into the reservoir to complete the cycle.  
         [0046]     In the retrieval mode of  FIG. 11B , working fluid moves from the reservoir  123  to the prime mover  121 . The positive displacement prime mover  121  pumps the working fluid through the three way valve  130 . In the retrieval mode, the three way valve handle  131  is in an upper position (as shown in  FIG. 11B ) that allows the working fluid to enter the casing annulus  19 . The working fluid enters the perforated production tubing  12  at perforations  114  but does not pass the packer  13 . This working fluid that travels in the annulus  19  flares the upper swab cup  37  against the production tubing  12  causing a seal. The tool body  15  provides a check valve  88  to prevent circulation of the working fluid through the tool body  15  to the oil producing formation that is below valve  88  and packer  13 . This arrangement causes the tool body  15  to lift upward and return to the wellhead  120  where it can be removed using an overshot. In  FIG. 11B , the tool body  15  can thus be pumped to the surface or wellhead area  120  for servicing or replacement. The power fluid or working fluid circulates through the three way valve  130  to the oil separator  125  and then to the reservoir  123  completing the cycle.  
         [0047]     In  FIG. 11C , a neutral mode is shown. When the tool body  15  is captured with an overshot, for example, the three way valve  130  is placed in a middle or neutral position as shown in  FIG. 11C . The  FIG. 11C  configuration causes the power fluid or working fluid to circulate through the three way valve  130  and directly to the separator  125  and then back to the reservoir  123 . The configuration of  FIG. 11A  produces zero pressure on the tubing  12 . A hammer union can be loosened to remove the tool body  15  and release the overshot. The tool body  15  can be removed for servicing or replacement. A replacement pump can then be placed in the tubing  12  bore  18 . A well operator then replaces the hammer union and places the handle  131  of the three way valve  130  in the down position of  FIG. 11A . The tool body  15  is then pumped to the seating nipple  14  as shown in  FIG. 11A , seating in the seating nipple  14  so that oil production can commence.  
       PARTS LIST  
       [0048]     The following is a list of suitable parts and materials for the various elements of the preferred embodiment of the present invention.  
         [0049]      10  oil well pump  
         [0050]      11  casing  
         [0051]      12  production tubing  
         [0052]      13  packer  
         [0053]      14  seating nipple  
         [0054]      15  tool body  
         [0055]      16  upper end portion  
         [0056]      17  lower end portion  
         [0057]      18  bore  
         [0058]      19  annulus  
         [0059]      20  arrow  
         [0060]      21  arrow  
         [0061]      22  arrow  
         [0062]      23  arrow  
         [0063]      24  arrow  
         [0064]      25  check valve  
         [0065]      26  pump mechanism  
         [0066]      27  oil flow arrow  
         [0067]      28  oil mix flow arrow  
         [0068]      29  return flow arrow  
         [0069]      30  filter, upper  
         [0070]      31  filter, lower  
         [0071]      32  neck section  
         [0072]      33  annular shoulder  
         [0073]      34  channel  
         [0074]      35  sleeve  
         [0075]      36  sleeve bore  
         [0076]      37  swab cup  
         [0077]      38  threaded connection  
         [0078]      39  annular socket  
         [0079]      40  swab cup  
         [0080]      41  annular socket  
         [0081]      42  spacer sleeve  
         [0082]      43  bore  
         [0083]      44  swab cup  
         [0084]      45  spacer sleeve  
         [0085]      46  bore  
         [0086]      47  annular socket  
         [0087]      48  valve housing  
         [0088]      49  threaded connection  
         [0089]      50  spring  
         [0090]      51  passageway  
         [0091]      52  sleeve  
         [0092]      53  bore  
         [0093]      54  filter disk  
         [0094]      55  retainer plate  
         [0095]      56  bolt  
         [0096]      57  shaft  
         [0097]      58  internal threads  
         [0098]      59  threaded connection  
         [0099]      60  connector  
         [0100]      61  external threads  
         [0101]      62  external threads  
         [0102]      63  pump mechanism housing  
         [0103]      64  internal threads  
         [0104]      65  working fluid discharge port  
         [0105]      66  produced oil discharge port  
         [0106]      67  flow passage  
         [0107]      68  connector  
         [0108]      69  external threads  
         [0109]      70  external threads  
         [0110]      71  flow passage  
         [0111]      72  shaft  
         [0112]      73  threaded connection  
         [0113]      74  retainer plate  
         [0114]      75  bolt  
         [0115]      76  filler disk  
         [0116]      78  threaded connection  
         [0117]      79  threaded connection  
         [0118]      80  sleeve  
         [0119]      81  bore  
         [0120]      82  internal threads  
         [0121]      83  threaded connection  
         [0122]      84  tapered section  
         [0123]      85  external threads  
         [0124]      86  bore  
         [0125]      87  o-ring  
         [0126]      88  check valve  
         [0127]      89  spring  
         [0128]      90  internal threads  
         [0129]      91  shaft  
         [0130]      92  keyed portion  
         [0131]      93  keyed portion  
         [0132]      94  upper rotor  
         [0133]      95  lower rotor  
         [0134]      96  shaped opening  
         [0135]      97  shaped opening  
         [0136]      98  outer rotor  
         [0137]      99  outer rotor  
         [0138]      100  lobe  
         [0139]      101  lobe  
         [0140]      102  lobe  
         [0141]      103  lobe  
         [0142]      104  lobe  
         [0143]      105  lobe  
         [0144]      106  lobe  
         [0145]      107  lobe  
         [0146]      108  spacer  
         [0147]      109  star shaped chamber  
         [0148]      110  star shaped chamber  
         [0149]      111  retainer  
         [0150]      112  passageway  
         [0151]      113  enlarged section  
         [0152]      114  perforations  
         [0153]      115  influent plate  
         [0154]      116  shaped opening  
         [0155]      117  effluent plate  
         [0156]      118  arrow  
         [0157]      119  arrow  
         [0158]      120  wellhead area  
         [0159]      121  prime mover  
         [0160]      122  flowline  
         [0161]      123  reservoir  
         [0162]      124  flowline  
         [0163]      125  separator  
         [0164]      126  flowline  
         [0165]      127  arrow  
         [0166]      128  flowline  
         [0167]      129  arrow  
         [0168]      130  three way valve  
         [0169]      131  handle  
         [0170]      132  retainer  
         [0171]      133  suction port  
         [0172]      134  suction port  
         [0173]      135  passageway  
         [0174]      136  shaped opening  
         [0175]      137  passageway  
         [0176]      140  reference dot  
         [0177]      141  reference dot  
         [0178]      150  upper gerotor device  
         [0179]      151  lower gerotor device  
         [0180]     The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.