Patent Publication Number: US-8978824-B2

Title: Turbomachinery with integrated pump

Description:
BACKGROUND 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     Pumps enable the flow of a fluid through various mechanical systems, such as turbomachinery. Turbomachinery may include pumps, turbines, and compressors. The pump may enable lubrication, cooling and/or sealing of the turbomachinery, thus increasing the operational life and efficiency of the turbomachinery. For example, heat generated by the turbomachinery may be transferred to a fluid and then transferred to a cooling medium. Likewise, the fluid may lubricate various mechanical components of the turbomachinery, decreasing friction between the components. Unfortunately, the pump may take valuable space, increasing the footprint of the turbomachinery. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying figures in which like characters represent like parts throughout the figures, wherein: 
         FIG. 1  is a schematic view of a turbomachinery including a bearing oil feed system, in accordance with one embodiment of the disclosure; 
         FIG. 2  is a perspective top view of a compressor including the bearing oil feed system of  FIG. 1 , in accordance with one embodiment of the disclosure; 
         FIG. 3  is an exploded perspective side-view of components of a bearing oil feed system and a gear, in accordance with one embodiment of the disclosure; 
         FIG. 4  is a cross-sectional side-view of the bearing oil feed system and gear of  FIG. 3 ; and 
         FIG. 5  is a cross-sectional top view of a crescent gear pump. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     One or more specific embodiments of the present invention will be described below. These described embodiments are only exemplary of the present invention. Additionally, in an effort to provide a concise description of these exemplary embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, the use of “top,” “bottom,” “above,” “below,” and variations of these terms is made for convenience, but does not require any particular orientation of the components. 
     The disclosed embodiments include a bearing oil feed system including a gear pump, such as a crescent gear pump. The bearing oil feed system may also include a bearing support system, such as a sleeve bearing. In certain embodiments, the bearing oil feed system may be incorporated in turbomachinery, such as a compressor, a pump, or a turbine, and used to mechanically support as well as lubricate certain components of the turbomachinery. In one embodiment, the gear pump is a crescent gear pump that minimizes its axial length by incorporating two gears inside of a pump housing. In other embodiments, the gear pump may be a spur gear pump (e.g., pump having two side-by-side meshing spur gears), a helical gear pump (e.g., pump having meshing helical gears), or a gerotor pump (i.e., generated rotor pump), also suitable for minimizing the gear pump&#39;s axial length. Additionally, the bearing oil feed system, including the gear pump, may be recessed within the turbomachinery, further reducing an axial profile of the bearing oil feed system. 
     The integrated bearing system of the bearing oil feed system may support a gear included in a rotor of a turbomachinery, such as a compressor. For example, the gear may include a “bull” gear of the compressor suitable for driving one or more compressor scrolls. Additionally, the bearing oil feed system may supply a lubricant and/or coolant, such as oil, to various regions of the integrated bearing (e.g., sleeve bearing) as well as to other components of the turbomachinery. Indeed, the bearing oil feed system may use integral passages in the bearing and/or in the turbomachinery to deliver the lubrication and/or cooling fluid. Such integral passages include internal bores formed by drilling, casting, milling, and so forth. The integral passages may also be used to couple the gear pump and bearing system to an integral modular lubrication system. The integral modular lubrication system may further reduce the size and profile of the turbomachinery by integrating components such as a filter, heat exchanger, thermal regulator, and valves with the turbomachinery, further streamlining the turbomachinery size and geometric profile. Indeed, an improved lubrication system having enhanced suction life capabilities and reduced noise may be constructed using the embodiments disclosed herein. 
     With the foregoing in mind and turning to  FIG. 1 , the figure is a schematic view of an embodiment of a turbomachinery  10  including a rotor  12  and a bearing oil feed system  14 . The bearing oil feed system  14  may further include a gear pump  16  and a bearing system  18  integrated within a turbomachinery component, such as a rotor  12 . The figure is also illustrative of an embodiment of an integral modular lubrication system  20  that is suitable for lubricating components of the turbomachinery  10 . Indeed, the integral modular lubrication system  20  may be integrated with the turbomachinery  10  and include internal or integral passages suitable for use as fluid conduits between components of the turbomachinery  10  and the integral modular lubrication system  20 . The use of internal or integral passages may reduce or eliminate the use of external piping for the conduit lubrication fluid. The turbomachinery  10  may be any type of turbomachinery, such as a compressor, a pump or a turbine. The rotor  12  may be any type of rotating device that would benefit from lubrication. For example, the rotor  12  may be a rotor  12  that includes a “bull” gear of a centrifugal compressor, as described in more detail below with respect to  FIG. 2 . 
     During rotor operations, the rotor  12  may rotate about an axis, directly or indirectly driving a load such as a compressor scroll  22 . It is to be understood that any mechanical load may be directly or indirectly coupled to the rotor  12  in addition to or alternative to the compressor scroll  22 . For example electrical generators, other scrolls, vanes, blades, and so forth, may be coupled to the rotor  12 . The rotor  12  is also coupled to the gear pump  16 . Accordingly, the rotation of the rotor  12  may also drive the gear pump  16 , creating a suction force or lift suitable for transferring a lubrication fluid from an oil tank  24  into the bearing oil feed system  14 . In certain embodiments, the fluid may be transferred through integral passages  26 . That is, passages or bores  26  internal to the turbomachinery  10  and/or rotor  12  may be used to direct the lubrication fluid into the bearing oil feed system  14 . In this way, the use of external plumbing and/or feed lines is minimized or eliminated, resulting in the turbomachinery  10  having a more streamlined geometry or profile. The integral passages  26  may be formed by any suitable technique, such as drilling, casting, milling, and so forth. 
     The lubrication fluid may be used to lubricate any number of components of the turbomachinery  10 , including the rotor  12 . Indeed, the lubrication fluid may be further distributed to lubricate seal faces, other bearings, gears, and so forth. The gear pump  16  may also distribute the lubrication fluid to the bearing system  18  and/or to the integral modular lubrication system  20 . Indeed, the bearing system  18  included in the bearing oil feed system  14  is a self-lubricating bearing system  18 , in which an increase in the rotational motion of the rotor  12  results in additional lubrication of the bearing system  18  as described in more detail below. 
     The gear pump  16  may also direct the lubrication fluid into the integral modular lubrication system  20  for further processing, by using, for example, internal or integral passages  28 . In other examples, external passages such as pipes or conduits may be used by the gear pump  16  to direct the lubrication fluid into the integral modular lubrication system  20 . The integral modular lubrication system  20  may then filter the lubrication fluid by using a filter or strainer  30  suitable for removing particulate matter or otherwise for cleaning the lubrication fluid. The lubrication fluid may then be directed via internal passages  32 , for example, into a heat exchanger  34  (e.g., cooler) suitable for cooling the lubrication fluid. More specifically, the heat exchanger  34  may cool the lubrication fluid by directing the lubrication fluid through a cooling medium, such as a gas or a liquid. Heat from the lubrication fluid may then transfer to the cooling medium, thereby reducing the temperature of the lubrication fluid. 
     In certain embodiments, a thermal regulator  36  may be included in the integral modular lubrication system  20 . The thermal regulator  36  enables a more constant operating temperature for the lubrication fluid, for example, by using an integral passage  38  to bypass the heat exchanger  34  so as to maintain a more uniform operating temperature. For example, if the lubrication fluid is below a certain temperature, then no cooling may be needed. Accordingly, the integral passage  38  may be used to bypass the heat exchanger  34 . Additionally, a pressure relief valve  40  may be used to maintain lubrication fluid pressure within a certain range. For example, should a pressure of the lubrication fluid exceed a certain limit, the pressure relief valve  40  may redirect a portion or all of the lubrication fluid flow into the oil tank  24  by using an integral passage  42 , thus relieving the pressure. Otherwise, the lubrication fluid may be directed to flow into the turbomachinery  10  and the rotor  12  through integral passages  44 . An integral passage  46  may then be used to transfer the lubrication fluid into the oil tank  24  for further reuse. By employing a bearing oil feed system  14  and an integral modular lubrication system  20 , the turbomachinery  10  may include enhanced lubrication capabilities while also minimizing size, axial length, and reducing or eliminating the use of external pipes or conduits. 
       FIG. 2  is a perspective top view of an embodiment of a turbomachinery  10  (e.g., centrifugal compressor  50 ), including the bearing oil feed system  14  directly coupled to the rotor  12 . In the depicted embodiment, three scrolls,  22 ,  52 , and  54  are connected to the rotor  12  through a “bull” gear  56 . The scrolls  22 ,  52 , and  54  are suitable to compress or pressurize a fluid, and may be used in stages. For example, the scrolls  22 ,  52 , and  54  may be used to force a refrigerant fluid outwardly, exerting a centrifugal force on the fluid. In one example, scroll  22  may be used as a first stage scroll, scroll  52  may be used as a second stage scroll, and scroll  54  may be used as a third stage scroll. The fluid may be compressed at a higher ratio at each successive stage, resulting in an efficient, high-ratio compression of the fluid. Larger diameter scrolls allow for a higher intake of fluid and a corresponding increase in compressor production. By axially reducing the length of the bearing oil feed system  14 , the diameters of the scrolls  22  and  52  may be enlarged. Indeed, an axially short bearing oil feed system  14  may enable the reduction or elimination of a distance d separating the two scrolls  22  and  52 . In one embodiment, the reduction of the axial protrusion of the bearing oil feed system  14  enables the two scrolls  22  and  52  to be approximately adjacent to each other, with no separation distance d. Accordingly, the bearing oil feed system  14  may include pumps having minimal axial lengths, such as gear pumps, and may be recessed into the “bull” gear  56  so as to enable the reduction or elimination of the separation distance d. Additionally, the bearing oil feed system  14  may be directly coupled to the gear  56  of the rotor  12 , thus providing for a self-lubricating bearing oil feed system  14  that may also pump lubricant fluid to other components of the compressor  50 . 
       FIG. 3  is an exploded side view of embodiments of the “bull” gear  56  and the bearing oil feed system  14  of  FIG. 2 . In the depicted embodiment, a shaft  58  included in the bearing oil feed system  14  and may be used to directly couple the bearing oil feed system  14  to the gear  56 . More specifically, the shaft  58  may axially traverse the bearing system  18 , and couple with a set of gears  60  and  62  of the gear pump  16 . The gears  60  and  62  may be disposed inside of a gear housing  64 , which may be securely connected to the bearing system  18  by using fasteners such as threaded bolts. The shaft  58  of the bearing oil feed system  14  may then be coupled to a shaft  66  of the “bull” gear  56 . The direct coupling of the shaft  66  to the “bull” gear  56  enables the gear pump  16  to pump whenever the “bull” gear rotates, as described below. 
     As the compressor  50  rotates the gear  56  around an axis, such as the Y-axis, the shaft  58  coupled to the gear  56  also rotates about the same axis. The bearing system  18  and housing  64  remain approximately stationary, enabling the gear  56  to rotate axially with respect to the bearing system  18  and the housing  64 . However, since the shaft  58  is coupled to the gears  60  and  62 , the gears  60  and  62  rotate with respect to the housing  64 . The rotating gears  60  and  62  create a suction lift suitable for transferring lubrication fluid from the oil tank  24  (shown in  FIG. 1 ) into the housing  64  through an inlet port  68 . In some embodiments, the lubrication fluid may be further directed into certain regions of the bearing system  18 , such as an outer cylinder wall  70  of the bearing system  18 , as described below with respect to  FIGS. 4 and 5 . In these embodiments, further rotation of the gear  56  will cause additional transfer of the lubrication fluid into the bearing wall  70 . Indeed, the self-lubrication bearing system  18  may transfer lubrication fluid based on the rotational motion of the gear  56 . 
       FIG. 4  is a cross-sectional view of the bearing oil feed system  14  recessed into the gear  56  and directly coupled to the gear  56  by using the shaft  58 . As mentioned above, the bearing system  18  of the bearing oil feed system  14  may be used as a main bearing (e.g., sleeve bearing) suitable for enabling a mechanical support of the gear  56 . Accordingly, an outer diameter of the cylinder wall  70  of the bearing system  18  may be approximately equal to an inner diameter of an inner chamber  72  of the gear  56 . The bearing system  18  may then be recessed into the chamber  72 , with the shaft  58  used to securely couple the bearing system  18  (and attached gear pump  16 ) to the shaft  66 . The two shafts  58  and  56  may then mechanically support the gear  56  and enable the rotation of the gear  56  about an axis  67 , such as the depicted Y-axis. 
     In the illustrated embodiment, rotation  67  of the gear  56  about the Y-axis results in an equivalent rotation  67  of the shaft  58 . Accordingly, the gears  60  and  62  connected to the shaft  58  will also rotate. The rotation of the gears  60  and  62  may create a suction effect or lift. More specifically, the rotation of the gears  60  and  62  may create an expanding volume on an inlet port  68 , which in turn creates a vacuum suitable for suctioning a flow  73  of lubrication fluid into the gear pump  16 . The lubricant fluid may then be contained or trapped inside internal voids such as a void defined by teeth of the gears  60  and  62  as described in more detail below with respect to  FIG. 5 . Further rotational motion of the gears  60  and  62  may result in the lubrication fluid being displaced into an outlet port  74 , resulting in an outwardly flow  75 . In certain embodiments, the outlet port  74  may be connected to the integral modular lubrication system  20  (shown in  FIG. 1 ), as well as to other components of the turbomachinery  10 . Accordingly, the fluid flow  75  may be used by the integral modular lubrication system  20  and/or other turbomachinery  10  components for lubrication and cooling. 
     As illustrated, an integral passage  76  may be used to direct lubrication fluid to the integral modular lubrication system  20  and/or other components of the turbomachinery  10 . Indeed, the integral passage  76  may direct lubrication fluid through the inside of the gear pump  16  and bearing system  18  for further use by the turbomachinery  10 , eliminating the need for external conduits. Additionally, an integral passage  78  may transfer lubrication fluid from the integral passage  76  into the cylindrical wall  70  of the bearing system  18 . By enabling a flow of lubrication fluid into the integral passage  78 , an interface between the cylindrical wall  70  of the bearing system  18  and the inner chamber  72  of the gear  56  may be kept suitably lubricated. It is to be understood that a variety of gear pumps  16  may be used for transferring lubricant in the bearing oil feed system  14 , such as a spur gear pump, a helical gear pump, a gerotor pump, or a crescent gear pump, which is described in more detail with respect to  FIG. 5 . For example, in a spur gear pump, two spur or star gears may be positioned side-by-side, with the two gears intermeshing with one another. In a helical gear pump, the two intermeshing gears may include a helical twist enabling a smoother flow of fluid. In a gerotor pump, a trochoidal inner rotor may be placed internal to an outer rotor having circular arcs. 
       FIG. 5  is a cross-sectional top view of an embodiment of the gear pump  16  including a crescent  80 , and the gears  60  and  62 . As depicted, the pump  16  includes multiple openings  82  suitable for attaching the pump  16  to the bearing system  18  (shown in  FIG. 4 ), e.g., with fasteners such as bolts. Also depicted in this embodiment is the flow  73  of lubrication fluid entering the gear pump  16  through the inlet port  68 . Such a flow  73  may be caused by the rotation of the gears  60  and  62  which in turn may be caused by a rotation of the shaft  58 . The shaft  58  may couple to gear  62  by extending into bore  69  of the gear  62 , and then a key insert of the shaft  58  may interlock with key slots  71  to secure the shaft  58 . The rotation of the gears  60  and  62  may cause the lubrication fluid flow  73  to enter the pump  16  and into voids between teeth of the gears  60  and  62 . As the flow  73  enters the pump  16 , the crescent  80  divides the liquid flow  73  and may also act as a seal between the inlet port  68  (i.e., suction port) and the outlet port  74  (i.e., discharge port). Eventually all of the voids in the pump  16  become flooded with liquid. Continued rotation of gears  60  and  62  then results in an intermeshing of the gears&#39; teeth, forcing the liquid between the voids to exit through the outlet port  74  (e.g., as the flow  75 ). Indeed, the gear pump  16  enables a non-pulsatile or continuous movement of fluid while using only two moving parts (i.e., gears  60  and  62 ). Additionally, the gear pump  16  exhibits improved noise reduction because of the reduced number of moving parts, while increasing the suction force or lift when compared to other pumps, such as screw pumps. 
     In one embodiment, the integral passage  76  may be disposed in a metal cylinder  84  of the pump  16  and used to direct some of the lubrication flow  73  into the integral passage  76 . As mentioned above with respect to  FIG. 4 , the integral passage  76  may direct the lubrication fluid into the wall  70  of the bearing system  18  and/or into the integral modular lubrication system  20 . In this embodiment, additional rotation of the gears  60  and  62  self-lubricates the bearing system  18 . That is, the rotation of the gears  60  and  62  directs additional lubrication fluid into the wall  70  of the bearing system  18  through the integral passage  76  and then to the integral passage  78  (shown in  FIG. 4 ). Indeed, continuous operation of the gear pump  18  results in a continuous lubrication of the bearing system  18  without the need to add other systems such as computer-based controllers. Further, the bearing oil feed system  14  may support a turbomachinery component, such as the gear  56 . Additionally the bearing oil feed system  14  may provide for suitable lubrication of other turbomachinery components. The use of gear pumps and the embedding of the bearing oil feed system  14  into the gear  56  substantially reduces the axial protrusion of the bearing oil feed system  14 . This reduced axial profile enables certain turbomachinery  10 , such as the compressor  50 , to include larger scroll sizes with a corresponding improvement in compression efficiencies. 
     While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.