Abstract:
An impeller-type pump includes a housing with an internal chamber, a rotor within the chamber and a vane mounted to the housing for reciprocating action such that an end of the vane contacts the rotor and effectively divides the chamber between induction and exhaustion rotor chambers. The rotor has a non-circular cross-sectional configuration, such that its outside surface forms a camming surface that drives the vane in a reciprocating fashion upon rototation of the rotor. The rotor may be oval in cross section or have a complex cross-sectional configuration with a substantially flat trailing face forming a stop to prevent reverse direction rotation, and a curved leading face which forms a cam surface to elevate the vane upon rotation of the rotor.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to an impeller or rotary pump, of the type comprising a housing (the “stator” portion of the pump) with an internal rotor and displaceable vanes located between the rotor and the rotor chamber wall for separating the induction and exhaustion or expulsion regions of the rotor chamber. Rotor rotation has the effect of continuously drawing fluid through the pump as the fluid sequentially passes through the induction and exhaustion regions. These regions are effectively formed on a continuous basis in the space between the rotor surface and the chamber wall between a fluid inlet and a fluid outlet. Arrangements of this type comprise positive displacement pumps, wherein each cycle of rotation displaces a substantially constant fluid volume regardless of inlet and outlet pressure, apart from the usually minor effects of fluid compression under pressure. Pumps of this type may be used for pumping fluid having a wide range of viscosities, ranging from gasses to relatively viscous liquids such as heavy oils and greases. The relative simplicity of such pumps makes them desirable for a wide range of applications, including all manner of industrial, commercial, marine, medical, and other uses. As well, with suitable modifications such pumps may be converted into turbines, wherein a pressure differential between fluid bodies may be converted into mechanical energy.  
         [0002]     Rotary vane-type pumps, which employ an internal rotor or impeller to drive a fluid, are known both for use as pumps and turbines. For example, the present inventor&#39;s previous U.S. Pat. No. 6,554,596 describes a rotary device having a plurality of vanes, wherein the stator includes a fluid inlet and outlet with an internal generally cylindrical bore. A rotor is mounted eccentrically within the bore (the axis of the rotor being displaced from the central axis of the bore), with a plurality of vanes extending radially outwardly from the rotor to provide a sealing contact between the internal bore surface and the rotor. This device may be used as a turbine to convert the energy of a flowing fluid into mechanical energy. Other arrangements are known, in which a rotor is eccentrically mounted within a bore, with a plurality of vanes extending from the exterior surface of the rotor for reciprocating movement relative to the rotor. Rotation of the rotor draws fluid into the space between the rotor and the inner wall of the bore, with the vanes serving to propel the fluid through the housing and out of the discharge conduit. The combination of the vanes and the eccentric mounting of the rotor provide a one-way flow of the fluid and effectively separates the chamber into a plurality of induction and exhaustion chambers.  
         [0003]     It is an object of the present invention to provide an improved vane-type rotary pump suitable for use with a range of fluid viscosities and which is relatively simple and inexpensive in its construction.  
       SUMMARY OF THE INVENTION  
       [0004]     In one aspect, the present invention comprises a rotary vane pump comprised of the following elements: 
        a stator, consisting of a stationary pump housing having, in sequential fluid communication with each other, a fluid inlet, a fluid outlet, and an internal pump chamber or bore having a cylindrical region;     a cam-shaped rotor mounted for rotation within the cylindrical region of the pump chamber, the rotor having a central axis of rotation and a non-cylindrical exterior cam surface for contact with the fluid being pumped. The rotor shape preferably comprises first substantially opposed portions each having an equal radius such that these opposed portions each form a sealing contact with the inside surface of the housing bore, and second rotor portions (which may also be substantially opposed to each other) having a reduced radius to form a space between the rotor surface and the inside surface of the rotor bore for receiving a volume of fluid for passage through the pump upon rotation of the rotor. The said spaces effectively form induction and exhaustion regions upon rotation of the rotor;        
 
         [0007]     a drive means for rotatably driving the rotor, said drive means comprising any convenient means for rotatably driving the rotor, including without limitation any type of motor, whether or not in direct mechanical linkage with said rotor. The drive means may comprise a fluid flow through said pump in the case of the pump being used as a turbine; and 
        at least one vane mounted to the housing and extending into the pump chamber. Preferably, only a single vane is provided although multiple vanes are contemplated. The vane is mounted for reciprocating motion relative to the housing and has a contact surface for contacting the cam surface of the rotor, such that the vane effectively divides the pump chamber into two regions on opposing sides of the vane during the phase of the rotor rotation when the cam surface thereof is not in contact with the chamber wall at the position of the vane. Each region on either side of the vane is defined by the space between the rotor surface and the chamber wall. A first region effectively forms an induction chamber and a second region forms an exhaustion chamber, such that fluid separation is maintained between the inlet and outlet. The contact between the vane and the cam surface of the rotor results in rotation of the rotor driving the vane in a reciprocating motion.        
 
         [0009]     The rotor may comprise various cross-sectional configurations, including being essentially or generally oval-shaped in section. Alternatively, the rotor may have a shape composed of opposing arms, each arm having a curved leading cam surface for elevating the vane upon rotation of the rotor and a trailing flat or substantially flat surface, such that the trailing surface effectively forms a stop member for abutting against the reciprocating vane to prevent reverse-direction rotation of the rotor. This configuration also increases the effective chamber volume, since only a single side of each rotor arm, the leading face, need be bowed outwardly. Other rotor configurations are possible within the scope of the invention.  
         [0010]     The central axis of the vane (i.e. the central plane defining the middle of the vane) may be aligned with the axis of rotation of the rotor or displaced relative thereto, for example when used with the type of rotor configuration described above having a flat trailing surface. Preferably, biasing means are provided for biasing the vane against the cam surface, for example (but not limited to) a spring or other member having a similar function. The differential pressure between pump inlet and outlet may also be harnessed to drive the vanes. Thus, a conduit may be provided from the pump outlet (having a higher pressure fluid) into the vane housing where up expansion of the fluid drives the vane towards the rotor. The vane may be housed within a slot or track within the housing. The contact surface of the vane may include an elongate roller bearing or other low-friction surface to minimize friction between the vane and the cam surface of the rotor. The vane is preferably a flat panel-like member and is optionally provided with a broadened portion at its lower edge where it contacts the rotor, such as bulbous region extending laterally outwardly from one or both sides of the vane.  
         [0011]     It will be further seen that the invention may be fabricated from any suitable material or combination of materials, including various metals and plastics suitable for the demands of the pump environment. As well, the pump may be provided either in isolation or as a component of another device.  
         [0012]     These and other features of the present invention will now be further illustrated by way of a detailed description of an embodiment of the invention, which is not intended to limit the scope of the invention.  
         [0013]     In the present specification, including the claims, various directional references are made such as upper, lower, vertical, horizontal, etc. These are intended merely for convenience of description and are not intended to limit the scope of the invention in any respect. It will be readily seen by persons skilled in the art that the present invention may be oriented in any position. Further, a degree of departure is permitted from strictly vertical, horizontal, and similar directional references.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     These and other advantages of the invention will become apparent upon reading the following detailed description and upon referring to the drawings in which:  
         [0015]      FIG. 1  is a schematic view, in cross-section, of a first embodiment of the invention;  
         [0016]      FIGS. 2   a  through  2   h  are schematic cross-sectional views of the first embodiment, illustrating sequential positions of the rotor and reciprocating vane to illustrate the pump cycle;  
         [0017]      FIG. 3  is a perspective view of the vane portion of the first embodiment;  
         [0018]      FIG. 4  is a schematic side elevational view of the vane portion of the first embodiment, the broken lines indicating hidden parts;  
         [0019]      FIG. 5  is a schematic cross-sectional view of a second embodiment of the invention;  
         [0020]      FIG. 6  is a schematic perspective view, partly in section, of the second embodiment;  
         [0021]      FIG. 7  is a further perspective schematic view, partly in section, of the second embodiment;  
         [0022]      FIG. 8  is a further perspective view of the vane portion of the second embodiment;  
         [0023]      FIG. 9  is a still further perspective view of the vane portion of the second embodiment.  
         [0024]      FIG. 10  is a schematic side elevational view of the vane portion of the second embodiment, the broken lines indicating hidden parts;  
         [0025]      FIG. 11  is a schematic perspective view of the vane portion of the second embodiment;  
         [0026]      FIG. 12  is a schematic perspective view of a third embodiment of the invention; and  
         [0027]      FIG. 13  is a perspective view of the exterior of the third embodiment. 
     
    
       [0028]     While the invention will be described in conjunction with the illustrated embodiments, it will be understood that it is not intended to limit the invention to such embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the scope of the invention as defined by the appended claims.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0029]     In the following description, part numbers have been assigned, with similar or corresponding parts in the separate embodiments being assigned the same number for convenience of description.  
         [0030]     The example described herein of the positive displacement vane-type pump  10  of the present invention comprises in general a static pump housing  12  having an internal chamber or bore  14 , for housing a rotor  20  and reciprocating vane  22 . Turning first to the embodiment illustrated in  FIGS. 1 through 4 , the pump housing  12  includes a fluid inlet  30  and a fluid outlet  32 . It will be seen that the relative dimensions of these and other components of the pump are presented merely by way of illustration and may be varied within a wide range according to the specific pump requirements. Such alterations and modifications are within the skill and knowledge of persons skilled in the art. The housing  12  includes a bore  14  for housing the rotor  20 , the bore  14  having a lower portion  34  which is cylindrical, the inner surface  36  of which provides a smooth contact surface for the rotor  20 . The rotor bore  14  includes opposed lateral side walls  38 , which as is described below, conform to the end walls  39  of the rotor  20  (parts  38  and  39  being visible in  FIGS. 6 and 7 ). The inlet  30 , rotor bore  14 , and outlet  32  are all in sequential fluid communication with each other. That is, at any given point during the pump cycle, fluid communication between the inlet  30  and outlet  32  is blocked by the combination of the rotor  20  and vane  22  in contact with each other and the inner surface  36  of the bore  14 , as will be described in detail below. Thus, the inlet and outlet are in fluid communication with each other to the extent that fluid entering the inlet passes sequentially through inlet, the rotor bore and the outlet during operation of the pump  10 .  
         [0031]     The housing  12  includes a block  40  for receiving and supporting the reciprocating vane  22 . The block includes a vertical channel  42  for housing the vane, with the channel  42  having flat lateral sides for contact with the corresponding faces of the vane  22 . The exterior of the vane block  40  protrudes upwardly from the pump to provide sufficient interior space within the block to accommodate the vane  22  when in the retracted position. A screw-threaded opening  44  extends through the upper surface of the block to the pump exterior and communicates with the interior of the channel  42 . A spring tension adjustment screw  46  is threaded through the opening and protrudes into the upper end of the channel. A spring  48  is housed within the channel  42 , and biases the vane  22  downwardly against the rotor  20 , as will be discussed in more detail below. It will be evident to those skilled in the art that the spring  48  may be replaced by any convenient biasing means, such as, without intending to limit the scope of the invention, a gas spring, a resilient member (such as an elastomeric rod), etc.  
         [0032]     Rotor  20  includes a central axle  50  which is journalled for rotation on an axle mount  52 , which is not shown but is conventional in design. The axle  50  is operatively connected to a drive for rotating the rotor  20 . The drive is not shown, but will be readily seen by those skilled in the art that any convenient drive means may be employed for rotating the axle and, in turn, the rotor. For example, depending on the pump application, there may be used any type of motor, hydraulic drive, or a hand crank for hand operation. As well, as will be described below, the invention may be operated as a turbine wherein an existing pressure differential between the inlet and outlet rotatably drives the rotor  20 , in which case no drive means need be provided for the rotor, as the fluid passing through the pump serves as the drive means. The rotor  20  is generally elongate and extends between the side walls  38  of the rotor bore. The opposed end walls  39  of the rotor  20  are flush with the corresponding side walls  38  of the bore  14  and in contact therewith to prevent or minimize fluid leakage. While flat end walls  39  are preferred, it will be seen that the end walls  39  and the corresponding side walls  38  of the bore may have any convenient shape or configuration. The rotor  20  is characterized by a non-cylindrical shape, namely having two opposed (either directly or substantially directly) and equal first radii (a) which define the maximum diameter of the rotor for any given point along its length (e.g. the rotor may be tapered or otherwise shaped along its length). The radii (a) define the outer margin of opposed arms  56  of the rotor and thus define opposed rotor edges  54  for contact with the cylindrical inside surface  36  of the rotor bore  14 . The rotor is further defined by opposed or near-opposed radii (b) which define the minimum rotor diameter. It will be seen that the rotor  20  and bore  14  may be tapered or otherwise shaped along their length which result in radii (a) and (b) varying along the rotor length.  
         [0033]     In the embodiment of FIGS.  1  to  4 , the rotor  20  is comprised of two similar opposing paddles or arms  56  extending from the central axis. The arms  56  each have a curved leading face  60  and an opposed flat trailing face  62 . The trailing face  62  of a first paddle  56  merges with the leading face  60  of the opposed paddle  56 . A stepped portion  64  characterizes the junction between the trailing face  62  of a first paddle and the leading face  60  of an opposed second paddle, having a downward step from the leading to the trailing faces. The stepped portion  64  includes a rounded exposed edge merging with an angled shoulder  66 .  
         [0034]     The reciprocating vane  22  according to the first embodiment of the present invention is shown in more detail in  FIGS. 3 and 4 . The vane  22  is generally planar with flat front and rear faces (although the vane may comprise other configurations such as arcuate in section). The vane  22  is composed of opposed lateral side shoulders  70  which sandwich a central (optionally) recessed panel  72 . The side shoulders  70  may be integral with the panel  72  and flush therewith (as will be described in greater particularity with respect to the second embodiment) or the panel  72  may be recessed relative to the side walls, as seen in  FIGS. 3 and 4 . The vane  22  and channel  42  within the vane block  40  are shaped to provide a snug fit, which is substantially impervious to fluid leakage while still permitting the vane to slide within the channel in a reciprocating fashion. The side shoulder portions  70  of the vane  22  fit within corresponding recesses  74  in housing  12  beside the vane block and aligned with channel  42 . Preferably, the upper face  78  of the vane  22  is substantially flat, while the side shoulders  70  extend downwardly past the lower edge of the central panel  72 , as seen in inverted view in  FIG. 3 . The lower edge of the central panel  72  includes a bulbous laterally-extending rounded protrusion  80  defining the lower edge of the central panel  72 . The bulbous protrusion  80  provides additional strength to the vane at the point of contact with the rotor. For maintaining a sealing contact with the rotor, an elongate roller bearing  82  is provided at the lower edge of the central panel. The roller bearing  82  fits within a corresponding receiving channel  84  within the vane  22  extending transversely across the lower edge thereof. The bearing  82  may comprise any convenient material, for example stainless steel or Teflon™.  
         [0035]     A further feature of the first embodiment is that the vane  22  is positioned within the housing  12  such that it is offset from the axis of rotation of the rotor  20 , such that when seen in side view, the central axis of the vane is to the left (downstream side) of the rotor axis. That is, it is offset towards the downstream side of the rotor axis. As will be described below, the shape of the rotor  20  in conjunction with the offset position of the vane  22  permits a one-way operation of the rotor and prevents the rotor from spinning in a reverse direction thereby blocking any countervailing flow from the outlet to the inlet. This shape optimizes the volume of the chamber thus increasing flow rates. The amount of offset of the vane  22  relative to the rotor axis is a function of the rotor thickness, i.e. the vane  22  is displaced from the rotor axis by a horizontal distance (c) which is equal to the horizontal distance between the flat rear face of the rotor and a vertical radius of the rotor  20 , when the rotor is in the vertical position. This displacement thus permits the vane  22  to slide downwardly into a position of full contact with the flat side of the rotor, when the rotor is in a vertical position as shown in  FIGS. 2F and 2G .  
         [0036]     Operation of the first embodiment will now be described by reference to  FIGS. 2A through 2H . In a first position shown in  FIG. 2A , the rotor  20  is generally horizontal, with the vane  22  in a substantially extended position such that it extends downwardly to contact the rotor  20 . Clockwise rotation of the rotor, as shown in  FIG. 2B , expands the effective size of the induction portion of the rotor chamber  14 , thus drawing fluid into the chamber  14 . Continued rotor rotation, as shown in  FIGS. 2C through 2E  continues to expand the relative size of the induction chamber, while the vane  22  is urged upwardly by contact with the leading face  60  of the rotor  20 , until the rotor reaches a substantially vertical position as shown in  FIG. 2F . At this point, the flat trailing face  62  of the rotor is aligned with the corresponding face of the vane  22 , and the vane thus moves downwardly, on the urging of the internal spring  48 . Preferably, the spring tension is adjusted to provide a very rapid downward movement of the vane. The vane is maximally extended at  FIG. 2G , with further downward movement of the vane being prevented by contact with the stepped portion  64  of the rotor  20 , which protrudes radially outwardly from the flat trailing face  62 . It will be seen that when the vane  22  abuts the trailing face  62 , the rotor  20  is prevent from rotating in a reverse (counter clockwise) direction.  
         [0037]     It will be seen that the trailing face  62  need not be substantially flat in order to achieve solely the objective of increasing the effective volume of the rotor bore  14  if there is no need for the anti-rotation feature. Thus, this feature is provided if trailing face  62  has a flatter surface than leading face  60 .  
         [0038]     Continued rotation of the rotor, as seen in  FIG. 2H , elevates the vane  22  while expelling fluid from the outlet  32  and effectively forming another induction chamber at the fluid inlet.  
         [0039]     A second embodiment of the invention is illustrated at  FIGS. 5 through 11 . In this version, there is shown the inlet  30  and outlet  32  being parallel and protruding from the upper face of the pump  10 , although it will be seen that with minor modifications horizontal inlets and outlets as in the first embodiment may be provided, or the inlet and/or outlet being in essentially any position. The rotor  20  of the second embodiment is generally oval and symmetrical in cross-section, and thus may rotate in either direction such that the inlet and outlet conduits may be reversed in function, depending on the direction of rotation of the rotor. The vane  22  (shown with more detail in  FIGS. 8 and 9 ) is generally similar to the vane of the first embodiment but with the bulbous portion  80  at the lower edge region of the vane extending laterally to an equal extent from either side of the vane. As well, the vane  22  may comprise a unitary panel structure (i.e. without protruding side rails) having depending stop members on either side which extend below the lower edge of the vane, as shown more particularly in  FIGS. 8 through 11 .  
         [0040]     In a further aspect of the second embodiment, shown in  FIGS. 10 and 11 , rather than the biasing means being housed within the vane block  40 , the vane itself is provided with spring-loaded push rods  90  which retract into corresponding apertures  92  within the vane.  FIGS. 8 and 9  show the vane with the push rods retracted while  FIGS. 10 and 11  show the push rods extended. These push rods  90  may be biased to protrude from the vane by any convenient biasing means, including a spring  94  or other resilient member.  
         [0041]     The vane block  40  includes a drainage opening or slot  96  communicating with the vane-receiving channel  42 , to permit fluid which has leaked into the main channel  42  to drain into the main fluid outlet  32 . The slot  96  potentially serves a second function. When oriented such that it opens towards the higher-pressure side of the pump (i.e. the downstream outlet), the slot  96  permits use of the inlet/outlet pressure differential to drive or assist in the driving of the vane  22 . Thus, the relatively high pressure fluid stream will enter the channel  42  in the space above the vane. Because this fluid is at a relatively high pressure, it will exert a biasing force against the vane  22  to urge it downwardly against the rotor  20 . This effect is enhanced by the provision of partly enclosed inlet and outlet chambers  95  and  97  respectively with the slot  96  opening into the outlet chamber  97 .  
         [0042]     As seen more particularly in  FIG. 7 , the vane block  40  only receives an upper portion of the vane  22  therein, with a lower portion of the vane  22  extending downwardly into the main chamber  14 .  
         [0043]     The lateral side walls of the chamber include opposed track slots aligned with the vane channel, for receiving and guiding the end wall portions of the vanes.  
         [0044]     As seen more particularly in  FIG. 5 , the vane  22  is aligned with the axis of rotation of the rotor  20 .  
         [0045]     In operation, the second embodiment operates in a similar manner to the first embodiment, although it will be seen that the symmetrical oval shape of the rotor does not provide for an anti-reversal function. The second embodiment has particular use for providing a reversible pump, that is, a pump which is equally capable of discharging the fluid through either conduit by reversing the direction of rotation of the rotor  20 .  
         [0046]     A third embodiment of the invention is illustrated at  FIGS. 12 and 13 . This embodiment is similar to the second embodiment, having a generally oval-shaped rotor  20 . However, the vane  22  is offset from the axis of rotation of the vane  20 , towards the outlet (downstream) side of the vane  22 . The offset position of the vane permits it to be more efficiently urged upwardly into its retracted position upon rotation of the rotor  20 . A further difference from the second embodiment resides in the shape of the bulbous lower protrusion  80  of the vane, which is similar in shape to the first embodiment. Further, the inlet and outlet regions  30  and  32  respectively are shown in an alternative arrangement, namely being generally horizontally disposed and offset from each other wherein the inlet enters the chamber at an elevated position relative to the outlet.  
         [0047]     Although the present invention has been described by way of a detailed description of the invention, including particular embodiments thereof, it will be seen by those skilled in the art that the present invention includes within its scope departures from and variations to the elements particularly described, including omission of inessential elements and addition of additional elements, without departing from the full scope of the invention. In particular, the scope of the invention is defined by the claims appended hereto, as these may be amended from time to time, and including any components, elements, or operation methods which are the functional or mechanical equivalent thereof.