Patent Publication Number: US-8985982-B2

Title: Rotary pump with a vane provided in each pump outlet

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of pumps. 
     BACKGROUND OF THE INVENTION 
     It is well known to use pumps to create flows of fluids such as liquids, and numerous types of pumps are known in the prior art, including vane pumps, self-priming pumps and centrifugal pumps. 
     SUMMARY OF THE INVENTION 
     Forming one aspect of the invention is a pump. The pump includes a housing having a cylindrical interior surface having one or more outlet ports defined in the housing. The housing has a pair of side surfaces defining, in combination with the cylindrical interior surface, a substantially cylindrical central chamber, the pair of side surfaces having one or more inlet ports defined in the housing. The pump further includes a rotor having a central void, one or more lobes and, for each lobe, a throughpassage. The rotor is positioned in the central chamber such that the central void is in communication with the one or more inlet ports to receive fluid therefrom and such that the throughpassage for each lobe provides for communication between the central void and the central chamber. The rotor is mounted for rotation in the chamber such that the lobes traverse the cylindrical interior surface during rotation. The pump further includes, for each of the one or more outlet ports, a vane. As the rotor turns in the chamber, the outer surface of the rotor is traversed by the vane to, in combination with the rotor and the housing, create, as the vane traverses a throughpassage, a chamber ahead of the vane which increases volume and communicates with the throughpassage, and a chamber behind the vane which decreases in volume and communicates with each outlet port. The pump further includes a valve arrangement adapted to block flow into the chamber via each outlet port at least when the vane for each outlet port is traversing a throughpassage. 
     According to another aspect of the invention, the vane can be mounted for reciprocating motion in a slot. 
     According to another aspect of the invention, the valve arrangement can be a check valve. 
     According to another aspect of the invention, the rotor can be an impeller which, in use, draws fluid through the one or more inlet ports into the central void. 
     According to another aspect of the invention, the rotor can have two lobes and the housing can have two outlet ports. 
     According to another aspect of the invention, the rotor can have three lobes and the housing can have four outlet ports. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a pump according to an exemplary embodiment of the invention; 
         FIG. 2  is an exploded view of the structure of  FIG. 1 ; 
         FIG. 3  is an enlarged view of a portion of the structure of  FIG. 2 ; 
         FIG. 4  is an enlarged view of another portion of the structure of  FIG. 2 ; 
         FIG. 5  is an exploded view of the structure of  FIG. 4 ; 
         FIG. 6  is a schematic cross-section of the pump in use; 
         FIG. 7  is a view similar to  FIG. 6  with the rotor advanced slightly counterclockwise relative to its position in  FIG. 6 ; 
         FIG. 8  is a view similar to  FIG. 7  with the rotor advanced slightly counterclockwise relative to its position in  FIG. 6 ; and 
         FIG. 9  is a view similar to  FIG. 6  but showing a pump according to another exemplary embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     A pump  20  according to an exemplary embodiment of the invention is shown in  FIG. 1  and, with reference to  FIG. 2 , will be seen to comprise a housing  22 , a plurality of vanes  24  and a rotor  26 . 
     The housing  22  has a main body  28  and a pair of side plates  30 , 32 . The main body  28  has a hollow  34  defined by a cylindrical interior surface  36 . Outlet ports  38  punctuate the interior surface  36  and lead through the main body  28 . The side plates  30 , 32  each have a side surface  40 , 40 ′ which collectively define, in combination with the cylindrical interior surface  36 , a cylindrical central chamber  42 . One of the side surfaces  40 ′ has an inlet port  44  defined therein leading into the central chamber  42 . 
     The vanes  24  are provided one for each outlet port  38 , each vane  24  being mounted for reciprocating motion in an adjacent slot  46 , the slots  46  being shown in phantom in  FIG. 3 . The slots  46  are also formed partly in the side plates  30 , 32 , as seen in  FIG. 2 . 
     The rotor  26 , which is mounted for rotation in said central chamber  42 , will be seen in  FIG. 4  to have a central void  45 , a plurality of lobes  48  and, for each lobe, a throughpassage  50 . One side of the rotor  26  defines an impeller  52 . 
     The position of the rotor  26  provides for communication between the central void  45  and the central chamber  42  via the throughpassages  50 . 
       FIGS. 6-9  show the pump  20  in a mode of operation and in schematic form and in these views it will be seen that the vanes  24  are positioned, orientated and move in use such that, as the rotor  26  turns in the chamber  42 , the outer surface of the rotor  26  is traversed by the vanes  24  without binding and the cylindrical interior surface  36  is traversed by the lobes  48 . 
     Further, during said rotation, as each vane  24  traverses a throughpassage  50 , i.e. as shown by the sequence of  FIGS. 6-7 , the vane  24 , in combination with the rotor  26  and the housing  22 , creates:
         a chamber ahead of said vane which increases volume and communicates with said throughpassage; and   a chamber behind said vane which decreases in volume and communicates with said each outlet port       

     The chambers increasing in volume in FIGS.  6 , 7  are clearly visible and indicated by reference numeral  54 . The chambers decreasing in volume are clearly visible in FIGS.  6 , 7  and indicated by reference numerals  56 . 
       FIG. 8  shows vanes  24  traversing the throughpassages  50 , during which process the chambers of increasing volume which communicate with the throughpassages are severed from the throughpassages, coupled to the outlet ports and become chambers of decreasing volume. In this position, it will be seen that neither increasing- nor decreasing-volume chambers are present, as fluid can pass freely across the rotor. In the absence of countermeasures, this could result in backwards flow, which would detract from pump operation. According, a valve arrangement, namely, a plurality of check valves  58 , is provided, and adapted to block flow into said chamber  42  via said each outlet port  38  at least when the vane  24  for said each port  38  is traversing a throughpassage  50 , i.e. as shown in  FIG. 8   
     In low speed operation, fluid can fill the central chamber by, for example, gravity, and can be forced in a positive displacement manner out the outlets  38  by the lobes  48 , as shown by, for example,  FIG. 7 . 
     At higher speeds, the impeller  52  can provide substantial assistance in terms of drawing flows into the central chamber  42 , i.e. the impeller  52  can draw fluid through the one or more inlet ports  44  into the central void. Displacement of the fluid still occurs via positive displacement. 
     At very high speeds, the vanes can be drawn into the slots [not shown], and fluid flow via the outlet ports can occur as a result of centrifugal force imparted to the fluid as it passes through the rotor. 
     Thus, the present invention permits the construction of a self-priming pump that is capable of transitioning between positive displacement and centrifugal operation. The pump is relatively inexpensive to construct and is relatively robust. 
     The manner of actuating the vanes is not shown nor described. However, persons of ordinary skill will readily appreciate that vane actuation can, for example, be affected at least by hydraulic or pneumatic means, by mechanical linkages and springs. Accordingly, a detailed description is neither required nor provided. 
     Whereas but a single embodiment is shown and described in  FIGS. 1-8 , variations thereon are possible. 
     For example, whereas a plurality of vanes and outlet ports are shown, greater or lesser numbers can be provided.  FIG. 9 , for example, shows an embodiment  20 ′ having three lobes and four outlet ports. Variation in the numbers of lobes and ports can change the frequency and severity of flow pulses, as persons of ordinary skill in the art will readily understand. 
     Yet further variations are possible. 
     Accordingly, the pump should be understood as limited only by the accompanying claims, purposefully construed.