Abstract:
The rotary piston power system includes a housing having a drum and a cover rotatably mounted on the drum. The drum has high pressure and low pressure ports defined in its peripheral wall and a central separator wall having arcuate end faces and a pair of semicylindrical recesses defined in opposing sidewalls. A pair of pistons are rotatably mounted on axles on opposite sides of the separator wall and fit closely between the separator wall and the peripheral wall. Each piston has a plurality of radially disposed cylindrical recesses defining slots in the piston&#39;s peripheral wall. The cover has a plurality of radially disposed vanes extending into the drum defining a number of cylinders or chambers double the number of recesses defined in a single piston. An input/output shaft extends from the opposite side of the cover for coupling to a prime mover or to a load.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to power systems for driving engines and compressors, and particularly to a rotary piston power system having rotating pistons disposed within a housing that includes a rotating cover either driving rotation of the pistons (in the case of a compressor) or driven by the input of pressurized fluid into the system (in the case of an engine). 
   2. Description of the Related Art 
   Reciprocating power plants generally rely on complex mechanical interconnections with a multitude of moving parts subject to mechanical failure. As a result, rotary engines and compressors have been suggested as an alternative that has fewer moving parts than a reciprocating engine, produces less vibration, and is capable of producing more horsepower than a reciprocating power system of the same or comparable size. However, even conventional rotary piston power systems, and particularly rotary engines, typically rely on a complex arrangement of a multiplicity of rotating and engaging parts, thus having poor energy efficiency due to frictional losses and losses through mechanical vibration, compared to a simple reciprocating power system having the same power output and having a minimum of moving parts. Conventional rotary power systems typically have an eccentric shaft and/or pistons that do not have a smooth curvature, rendering the parts expensive to manufacture, prone to mechanical failure, and difficult to maintain a proper seal in the chamber(s). 
   Thus, a rotary piston power system solving the aforementioned problems is desired. 
   SUMMARY OF THE INVENTION 
   The rotary piston power system is a dual-rotary piston device. In some embodiments, the system may be configured as a fluid-driven engine, while in other embodiments the device may be configured as a fluid compressor. The rotary piston power system includes a housing having a drum and a cover rotatably mounted on the drum. The drum has high pressure and low pressure ports defined in its peripheral wall and a central separator wall having arcuate end faces and a pair of semicylindrical recesses defined in opposing sidewalls. A pair of pistons are rotatably mounted on axles on opposite sides of the separator wall and fit closely between the separator wall and the peripheral wall. Each piston has a plurality of radially disposed cylindrical recesses defining slots in the piston&#39;s peripheral wall. The cover has a plurality of radially disposed vanes extending into the drum defining a number of cylinders or chambers double the number of recesses defined in a single piston. An input/output shaft extends from the opposite side of the cover for coupling to a prime mover or to a load. 
   When configured as a compressor, air or other compressible fluid at atmospheric or low pressure enters the drum through the low pressure ports. A prime mover coupled to the input shaft rotates the cover, the vanes alternately engaging the pistons and causing the pistons to rotate, compressing the fluid as the volume of the cylinders or chambers is reduced when rotating past the pistons, the compressed fluid being discharged through the high pressure ports. 
   When configured as an engine, fluids introduced through the high pressure ports impact the vanes, causing the cover to rotate. Output is coupled from the output shaft to the load. 
   These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view of a rotary piston power system according to the present invention. 
       FIG. 2A  is a transverse section view through the housing of a first embodiment of the rotary piston power system according to the present invention configured to act as a compressor. 
       FIG. 2B  is a transverse section view through the housing of a second embodiment of the rotary piston power system according to the present invention configured to act as an engine. 
   

   Similar reference characters denote corresponding features consistently throughout the attached drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 ,  2 A and  2 B illustrate a rotary piston power system  10 , which may be configured as either a fluid-driven engine or a fluid compressor.  FIG. 2A  illustrates the system  10  being utilized as a fluid compressor and  FIG. 2B  illustrates the system  10  being utilized as a fluid-driven engine, as will be described in detail below. The system  10  includes a pair of rotary pistons  14  received within a housing that includes a drum or base member  12  and a cover  16  rotatably attached to the base member  12 . 
   When configured as a compressor, as illustrated in  FIG. 2A , a compressible fluid, such as a gas, enters the base  12  through low pressure ports  24  at a relatively low pressure and is compressed by the rotary pistons  14 , thereafter being expelled or exhausted through high pressure ports  22  under a relatively high pressure, thus providing high pressure compressed fluid to be used as a driving force in a pressurized fluid-driven system. 
   The system  10  may alternatively be configured as a fluid-driven engine, shown in  FIG. 2B , by reversing the rotation direction and the fluid flow; i.e., high pressure fluid is driven through high pressure ports  22 , which impacts vanes  20  or causes a pressure differential in the chambers on opposite sides of the vanes  20  which, in turn, causes cover member  16  and pistons  14  to rotate, as will be described below. It should be noted that the fluid compressor of  FIG. 2A  includes high pressure input ports  22  which are angularly positioned closer to low pressure ports  24  than in the fluid-driven engine of  FIG. 2B , the operational details of which will be described in further detail below. 
   Cover member  16  may have a shaft  18  projecting therefrom, which allows for either coupling of shaft  18  to a prime mover for driven rotation of cover member  16  when configured as a compressor, or allows coupling of shaft  18  to a load so that the rotation of cover member  16  is utilized as a rotational energy source when system  10  is configured as an engine. 
   Rotary pistons  14  and cover member  16  are the only moving parts of the system, thus minimizing the generation of unwanted noise, vibration and loss due to friction in the system. Additionally, as shown in  FIG. 2B , when the system  10  is utilized as an fluid-driven engine, fluid under pressure is input under relatively high pressure (as shown by arrows  140 ) through high pressure ports  22  and output from system  10  through low pressure ports  24  (as shown by arrows  130 ). When system  10  is utilized as a compressor, shown in  FIG. 2A , fluid under relatively low pressure is input into system  10  through low pressure ports  24  (shown by arrows  120 ), and output through high pressure ports  22  (shown by arrows  110 ). In  FIG. 2A , both the cover  16  and pistons  14  rotate in a clockwise direction, and when fluid flow is reversed, as in  FIG. 2B , the cover  16  and pistons  14  rotate in a counter-clockwise direction. 
   As shown in the drawings, base  12  is formed as a cylindrical shell or drum having a circular disk  13  and a peripheral wall  40  extending from the periphery of the disk  13 , with the top end being open. Although base  12  may have any desired shape, it is preferable to form base  12  as a cylindrical shell for purposes of rotation, as will be described in further detail below. A pair of high pressure ports  22  and a pair of low pressure ports  24  are formed through the peripheral wall  40  of base  12 . Although two of each type of port are shown in  FIG. 1 , any suitable number may be formed through the sidewall  40  of base member  12 , depending on the needs of the user. It will be noted that the location of ports  22  and  24  relative to the pistons  14  is fixed, with one high pressure port  22  and one low pressure port  24  combination being disposed approximately every 180° in a dual piston system. The size and angular placement of the ports  22  and  24  varies, however, dependent upon whether the system  10  is configured as a compressor or an engine, as shown by comparison of the ports  22  and  24  in  FIGS. 2A and 2B . 
   A separation member or separator wall  42  is formed in the interior of base member  12  and extends from disk  13 . As shown in  FIGS. 1 ,  2 A and  2 B, the separator wall  42  has arcuate, convex end faces  43  and a pair of semicylindrical recesses  38  defined in opposing sides of the separator wall  42 . It should be noted that the configuration of separator wall  42  and end faces  43  are for exemplary purposes only and the exact curvature and spacing between elements in system  10  is dependent upon the needs of the user. 
   Axles  36  project from disk  13  within the opposing recesses  38 , as shown in  FIG. 1 . Each rotary piston  14  has a bore  34  formed therethrough. Rotary pistons  14  are rotatably mounted on axles  36  with axles  36  extending through bores  34 , the pistons  14  extending between the separator wall  42  and the peripheral wall  40  of base  12  with a close tolerance. A plurality of substantially cylindrical recesses  26  are formed in each piston  14 , with the longitudinal axis of each recess  26  being parallel to bore  34 . Each cylindrical recess  26  forms both an opening in an upper surface of the respective piston  14  and an slot  27  in the peripheral wall of the piston  14 , with both the top openings and slots  27  being in communication with one another, as best shown in  FIG. 1 . 
     FIGS. 1 ,  2 A and  2 B show three recesses  26  being formed in each piston  14 . However it should be understood that the number of recesses formed in each piston may be selected dependent upon the needs of the user. Recesses  26  are formed in the piston  14  at equal radial angles, e.g., the three recesses  26  are disposed 120° apart, defining a piston with three lobes. As will be discussed in further detail below, recesses  26  receive vanes  20  of cover  16 . When configured as a compressor, rotation of cover  16  generates rotation of rotary pistons  14  through engagement of vanes  20  with slots  27  and recesses  26 , and similarly, when fluid is charged into system  10 , rotation of vanes  20  causes rotation of pistons  14  through the engagement between vanes  20  and recesses  26  when system  10  is configured as a fluid-driven engine. 
   As shown in the drawings, vanes  20  are mounted equiangularly from each other along a periphery of cover member  16 . Vanes  20  extend radially inwardly from the circumference of cover member  16 , and taper in thickness from wide to narrow as they extend inwardly. The taper of the vanes  20  enables smooth engagement with the edges of slots  27  in pistons  14  as the cover  16  rotates. Each vane  20  provides a fluid-tight seal with the corresponding slot  27  when vane  20  engages slot  27 . The number of vanes  20  is twice the number of cylindrical recesses  26  defined in the pistons  14 , so that each piston makes two full revolutions for each full revolution of the cover  16 . 
   Cover member  16  is best shown in  FIG. 1 . The cover member  16  is shown as having a circular cross section, but any desired contour may be selected. The circular cross-sectional contour is preferable, as it is necessary for cover member  16  to form a fluid-tight seal with base member  12  and for cover member  16  to be rotatable with respect to base  12 . 
   A shaft  18  is formed on a top surface of cover  16  and projects centrally therefrom. Shaft  18  is utilized to drive rotation of cover  16  with respect to base member  12  when system  10  is used as a fluid compression system by coupling shaft  18  to a prime mover. Alternatively, when system  10  is configured as a fluid-driven engine, cover  16  is made to rotate by the fluid input into system  10  under a relatively high pressure. This rotation drives shaft  18 , allowing the rotational energy to be utilized by rotationally driven systems mechanically connected to shaft  18 . 
   Projecting from a lower surface of cover  16  are a plurality of vanes  20 . As shown in  FIGS. 2A and 2B , vanes  20  each taper in thickness as they extend radially inward to form wedges, which engage and disengage recesses  26  of pistons  14  when cover  16  rotates with respect to base  12 . The alternating engagement and disengagement of recesses  26  and vanes  20  allows for mechanically driven rotation of pistons  14  when system  10  is utilized as a fluid compressor, as will be further discussed below, and, similarly, the engagement and disengagement of recesses  26  and vanes  20  is produced in an opposite direction, creating reverse rotation, when the system is utilized as a fluid-driven engine (as illustrated in  FIG. 2B ). As shown in  FIGS. 2A and 2B , vanes  20  have a length slightly less than the distance between peripheral wall  40  and the convex end walls  43  of separator wall  42 , so that there is a close tolerance or seal between the vanes  20  and the separator wall  42  when the vanes  20  do not engage the slots  27  or cylindrical recesses  26  of pistons  14 . 
   As shown in the embodiment of  FIGS. 2A and 2B , six vanes  20  are provided. Although the number of vanes  20  is dependent on the desires and needs of the user, it is preferred that the number of vanes  20  be twice the number of recesses  26  formed in each rotary piston  14 . This configuration produces optimal conditions for fluid compression and expulsion, since rotary pistons  14  will rotate at twice the angular velocity as cover member  16 , which, in turn, produces optimal efficiency for the engine or compressor  10  and maintains both pistons  14  and cover  16  in close alignment, as will be further described below. 
   As may be apparent from inspection of  FIGS. 2A and 2B , the cover  16  necessarily has an interior diameter that is equal to twice the diameter of one of the pistons  14 . Thus, a one-half rotation of cover  16  will cause a full rotation of each piston  14 . This one-to-two rotational correspondence ensures proper alignment of the three moving parts of the system (i.e., each recess  26  will always engage the same pair of vanes  20 , spaced 180° apart from one another), increasing efficiency and reducing the chances of noise, vibration or frictional losses in the system. 
   In the drawings, system  10  is shown as having six vanes  20  mounted on cover member  16 , with three recesses  26  formed in each piston  14 . As described above, this is for exemplary purposes only, although it is desired that the number of vanes  20  be twice the number of recesses  26  formed in each rotary piston  14 . In the exemplary configuration shown in the drawings, the vanes  20  are arranged at 60° increments about the periphery of cover member  16 , with vanes  20  being positioned equiangularly from one another. Recesses  26  are positioned at 120° increments about the rotational axis of each piston  14 . As described above, the 2:1 ratio of the number of vanes  20  with respect to the number of recesses  26  in each piston  14  acts as a 2:1 gear ratio. Further, as shown in  FIGS. 2A and 2B , when one of vanes  20  engages a respective one of recesses  26 , a fluid-tight seal is formed in the side opening of the recess  26 . 
   In operation as a fluid compressor, as shown in  FIG. 2A , which illustrates the rotor parts of  FIG. 1  fully assembled, vanes  20  engage and disengage recesses  26  as cover  16  and pistons  14  rotate with respect to base  12 . Each adjacent pair of vanes  20 , together with the peripheral wall  40 , separator end wall  43 , disk  13 , and cover  16 , defines a compartment  28 ,  30 , or  32 . When system  10  is configured as a fluid compressor, fluid under a relatively low pressure enters base  12  through low pressure ports  24  and is contained initially in low pressure regions  30 . Cover  16  is driven to rotate (clockwise in the example of  FIG. 2A ) through driven rotation of shaft  18 , causing vanes  20  to alternately engage and disengage the recesses  26 , which, in turn, causes pistons  14  to rotate, also in a clockwise direction, causing the lobes of the piston  14  to alternately enter compartments  28 ,  30  or  32 , decreasing the volume and creating a region of high pressure fluid  28 , which is discharged through high pressure ports  22 . As shown in  FIG. 2A , vanes  20  form a fluid-tight seal with separation member  42 . As shown at the top and bottom of  FIG. 2A , fluid is temporarily trapped between pairs of vanes  20 , pistons  14  and the separation member  42 , maintaining the fluid in this region at a constant pressure until the fluid is output through a corresponding output port. 
   As cover  16  and pistons  14  rotate, the fluid in high pressure regions  28  is compressed, increasing fluid pressure in these regions. Simultaneously, pressure in low pressure regions  30  is decreased, thus drawing more fluid through low pressure ports  24 . High pressure fluid is expelled through high pressure ports  22 , which may then be drawn off and used in a system requiring pressurized fluid. 
   Device  10  may also be used as a rotary motor or engine, as illustrated in  FIG. 2B . In reversing the fluid flow, high pressure fluid is injected into system  10  through high pressure ports  22 , which, in turn, causes a reverse rotation to that described above of cover member  16  and rotary pistons  14 . As described above, the high pressure ports  22  in the configuration of  FIG. 2A  are angularly positioned closer to low pressure ports  24  than in the engine configuration of  FIG. 2B , but both the high pressure  22  and low pressure  24  ports are larger in size when the system  10  is configured as an engine. The rule is that the position of the ports  22  and  24  is designed so that no compartment  28 ,  30  or  32  is open to two ports  22  and  24  at any time. Fluid is released through low pressure ports  24  and may be driven back through high pressure ports  22 . Subsequent rotation of cover  16  creates rotation in shaft  18 , which may be used to drive a rotary system. The engagement and disengagement of vanes  20  with the pistons  14  is similar to that described above with respect to  FIG. 2A , however, the rotation of the moving parts is now reversed (as illustrated by the directional arrows). 
   The smooth continuous rotation of the elements of system  10  provides for a high-efficiency motor or compressor, which reduces noise and vibration and can be operated in a fuel-efficient manner. Further, forces act along the axes of the moving parts, thus reducing friction within the system. Only the cover member  16  and the rotary pistons  14  act as moving parts, thus minimizing the generation of unwanted noise, vibration and frictional loss. Frictional loss may further be minimized through the addition of a suitable lubricant between the moving parts. The smooth, continuous curvature of the pistons  14 , base  12 , separator wall  42 , and cover  16  are economical to produce and reduce wear, providing durability of the parts. 
   It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.