Patent Document

BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates generally to devices used to distribute fluent material, and more particularly to a device that divides a material flowing from a single source or a small number of sources into a plurality of streams of substantially equal volumetric flow rate. 
   2. Description of the Related Art 
   It is desirable in food processing applications to slice ground sausage rapidly and deposit the sausage on a moving substrate, such as a conveyor belt, beneath the slicing machine. Sausage is commonly made in specialized sausage-making machines that are known in the food processing industry. These machines, and machines that are made to pump previously-ground sausage, produce a stream of ground sausage that is fluent enough to be conveyed as a fluid, but which contains solids and semi-solids, and therefore it cannot be treated as a homogeneous material. Because of the heterogeneity of raw sausage, and the difficulty of conveying such a material conventionally, sausage is often placed in food slicing machines in batches of frozen or semi-frozen logs of a predetermined volume. 
   In order to produce ground sliced sausage patties rapidly enough to be economically feasible, a machine must not only slice the sausage rapidly, but it must slice the sausage in each of a plurality of lanes that are aligned above and across the moving substrate. These lanes must produce uniform slices, which requires that conditions be uniform in each lane. However, a batch process is particularly inefficient and susceptible to contamination due to the time and cost of producing chilled logs of product and the handling of such logs by personnel. Furthermore, when a slicing machine has several lanes slicing ground sausage in a batch process, there is inefficiency introduced in the form of lost time during refilling, and loss of material at the beginning and end of each log. 
   It is desirable to have a device that facilitates the use of a continuous process rather than a batch process in order to eliminate the inefficiencies inherent in a batch process, to minimize potential contamination, and to avoid the inconsistencies inherent in batch processes. However, in order to obtain consistent slice characteristics in each of the lanes, any device that conveys sausage to the plurality of lanes must supply the sausage at a volumetric flow rate that is equal in each lane. Equal volumetric flow rate has only been possible conventionally using. the batch process, because it has been impossible before the present invention to convey a heterogeneous material such as raw sausage in a plurality of flowing streams of equal volumetric flow rates. 
   BRIEF SUMMARY OF THE INVENTION 
   The invention is a flow divider for receiving fluent matter from at least one source, such as a sausage pump, and dividing the fluent matter substantially equally among a plurality of destinations, such as the parts of a food slicing machine corresponding to each of the lanes above a conveyor belt. The invention could alternatively be operated in reverse to function as a mechanism to combine fluent matter from a plurality of sources. 
   The flow divider comprises a housing with a first chamber. The first chamber is defined by a first radially inwardly facing surface and a first wall. The first chamber has an inlet in fluid communication with said at least one source and an outlet in fluid communication with a first one of said plurality of destinations. A first cylindrical hub is rotatably mounted in the first chamber, a first radial slot extends through the first hub, and a second radial slot extends through the first hub transverse to the first slot. A first vane is slidably mounted in the first slot, and a second vane is slidably mounted in the second slot. Each of the vanes has opposite vane ends seating against the first radially inwardly facing surface. 
   The flow divider includes a second chamber in the housing. The second chamber is defined by a second radially inwardly facing surface and a second wall, and the second chamber has an inlet in fluid communication with said at least one source and an outlet in fluid communication with a second one of said plurality of destinations. Thus, each chamber has an inlet in fluid communication with the source, and each chamber has an outlet in fluid communication with a corresponding unique destination. Therefore, sausage enters the housing and is divided by the apparatus into equal volumetric flow rate streams going to each destination. 
   A second cylindrical hub is rotatably mounted in the second chamber and is drivingly linked to the first hub. The second hub has a third radial slot and a fourth radial slot transverse to the third slot. A third vane is slidably mounted in the third slot and a fourth vane is slidably mounted in the fourth slot. Each of the vanes has opposite vane ends abutting the second radially inwardly facing surface. 
   The flow divider can also include a third and other additional chambers, each being essentially modular and having a substantially identical, or modified, hub, vanes, inlet and outlet. This modular nature of the invention&#39;s components permits the construction of a device that causes the flow of fluent material from a source to be divided into essentially as many equal flow rate destination streams as is desirable. In a preferred embodiment, the housing comprises a plurality of attached housing bodies, and the housing bodies, hubs and vanes can all be disassembled for thorough cleaning. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is an end view illustrating the preferred housing body. 
       FIG. 2  is a view in section through the line A—A of  FIG. 1 . 
       FIG. 3  is a view in section through the line B—B of  FIG. 1 . 
       FIG. 4  is a side view illustrating the preferred hub. 
       FIG. 5  is an end view illustrating the preferred hub. 
       FIG. 6  is an end view illustrating the preferred hub. 
       FIG. 7  is a side view illustrating the preferred vane. 
       FIG. 8  is an edge view illustrating the preferred vane. 
       FIG. 9  is an exploded view in perspective illustrating the preferred housing body and its corresponding hub and vanes. 
       FIG. 10  is view in perspective illustrating the preferred hub with corresponding vanes in an operable position on the hub. 
       FIG. 11  is a view in perspective illustrating the preferred hub and vanes in an operable position in the housing body. 
       FIG. 12  is an exploded view in perspective illustrating the preferred housing body, hub and vanes combined with another housing body, hub and vanes. 
       FIG. 13  is an exploded view in perspective illustrating a plurality of housing bodies, hubs and vanes mounted together. 
       FIG. 14  is a view in perspective illustrating the preferred embodiment of the present invention. 
       FIG. 15  is an end view illustrating one of the preferred end caps. 
       FIG. 16  is an end view illustrating another of the preferred end caps. 
       FIG. 17  is an end view illustrating the opposite end of the end cap shown in  FIG. 16 . 
       FIG. 18  is a side view in section through the line A—A of the end cap of  FIG. 17 . 
       FIG. 19  is an end view illustrating the opposite end of the end cap shown in  FIG. 15 . 
       FIG. 20  is a side view in section through the line A—A of the end cap of  FIG. 19 . 
       FIG. 21  is an exploded view in perspective illustrating an alternative hub with more than two vanes. 
       FIG. 22  is a view in perspective illustrating the alternative hub shown in  FIG. 21 . 
   

   In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific term so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word connected or term similar thereto are often used. They are not limited to direct connection, but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art. 
   DETAILED DESCRIPTION OF THE INVENTION 
   The housing body  10  is illustrated in  FIGS. 1 to 3 , and is a preferably rectangular block with a central, cylindrical bore defined by the radially inwardly facing, preferably cylindrical, surface  14 . The housing body  10  could alternatively have other exterior shapes. A wall  18  is formed on one longitudinal end of the housing body  10 , and the wall  18  has an aperture  20  formed therethrough. The aperture  20  is defined by a radially inwardly facing sidewall  21  that is preferably circular cylinder. The axis of the sidewall  21  is offset from the center of the radially inwardly facing cylindrical surface  14 , as described below. 
   For the purposes of the present invention, the term “longitudinal” is defined as substantially parallel to the axis of the bore defined by the radially inwardly facing cylindrical surface  14 . Additionally, the terms “cylindrical” and “cylinder” include not only the commonly-understood circular cylinder, but also all other polygonal cylinders, such as elliptical cylinders, rectangular cylinders and oddly-shaped cylinders. Although the radially inwardly facing cylindrical surface  14  preferably forms an elliptical cylinder, it could be modified to form cylinders having other shapes. 
   A hub  30  is shown in  FIGS. 4 to 6  having a main body  32  with a preferably circular cylindrical outer surface, a reduced-diameter, preferably circular cylindrical necked region  34  and a pair of transverse radial slots  36  and  37  extending longitudinally the length of the main body  32 . A pair of protrusions, preferably the tangs  38   a  and  39   a , extend longitudinally from one end of the hub  30 , and are radially aligned on opposite sides of the hub&#39;s  30  axis, as shown in  FIGS. 4 and 5 . Additionally, a pair of corresponding recesses, preferably the slots  38   b  and  39   b , are formed in the opposite end of the hub  30 , as shown in  FIG. 6 . 
   In an operable orientation, the hub  30  is mounted in the chamber of the housing body  10  that is defined by the radially inwardly facing cylindrical surface  14  and the wall  18 . The necked region  34  is inserted through the aperture  20 , which has a diameter that is only a very small amount (e.g.,0.002 inch) larger than the diameter of the necked region  34 . Because of the close tolerances and because the housing body  10  and hub  30  are preferably made of a very low friction, food grade material, such as that sold under the trademark DELRIN, the hub  30  can rotate relative to the sidewall  21 , but there can be no substantial radial movement of the hub  30  relative to the housing body  10 . Furthermore, the shoulder  33 , which is formed where the necked region  34  meets the main body  32 , seats against the wall  18  when the hub  30  is mounted in the housing body  10 . Therefore, longitudinal movement of the hub  30  relative to the housing body  10  in one direction, i.e., toward the wall  18 , is prevented when the hub  30  is in its operable position. Movement of the hub  30  away from the wall  18  is possible when the hub  30  is first mounted to the housing body  10 , but not when the invention is fully assembled as discussed below. 
   The substantially identical planar vanes  50  and  52  shown in  FIGS. 7 and 8  are preferably rectangular with notches  54  and  56 , respectively, formed intermediate the opposing vane ends. Also preferably formed of low friction, food grade material such as DELRIN, the vanes  50  and  52  are inserted in the slots  36  and  37  formed in the body  30  as shown in  FIGS. 9 and 10 , by aligning the notches  54  and  56  in a facing relation to one another. Thus, the vanes  50  and  52  are aligned transverse, and preferably substantially perpendicular, to one another in the preferably substantially perpendicular slots  36  and  37  in the hub  30 . The vanes  50  and  52  are 0.245 inches thick, approximately 4 inches long and approximately 2 inches wide in one embodiment. 
   The vanes  50  and  52  cross over one another, and the longitudinal length of the vanes in their operable position shown in  FIG. 10  is no greater than the longitudinal length of each vane. This is due to the notches  36  and  37  that permit overlapping of the vanes  50  and  52 . Of course, there could be more than two vanes on a hub, as shown in  FIGS. 21 and 22 . 
   When the hub  30  is mounted with the necked region  34  inserted in the aperture  20 , and the vanes  50  and  52  are in the operable position on the hub  30  as shown in  FIG. 11 , the radially extreme tips of the vanes  50  and  52  seat against the radially inwardly facing cylindrical surface  14  in a sealing manner and the longitudinally extreme edges also seat in a sealing manner against the wall  18  and an opposing wall described below. The axis of rotation of the hub  30  is aligned coaxially with the aperture  20 , but is positioned nearer to one radial end of the elliptical, radially inwardly facing cylindrical surface  14  than the opposite end. Rotation of the hub  30  about its axis causes the tips of the vanes  50  and  52  to slide along the radially inwardly facing cylindrical surface  14 , which surface varies in its distance from the hub&#39;s axis of rotation. This variation causes the vanes  50  and  52  to be displaced radially as the hub  30  rotates about its axis. Thus, rotation of the hub  30  through multiple revolutions causes the vanes  50  and  52  to slide in a reciprocating manner through the slots  36  and  37  in the hub  30  while the radially extreme tips of the vanes  50  and  52  maintain contact with the radially inwardly facing cylindrical surface  14 . 
   The preferred elliptical cylinder is defined as having a Major Axial Diameter (D maj ), a Minor Axial Diameter (D min ) no greater than 1.5 times the diameter of the hub (D h ), and an elliptical ratio (D maj /D min ) of no greater than 1.05:1.D min  is preferably equal to the length of the vane, and D maj  is preferably no more than the vane length multiplied by 1.05. Of course, elliptical shapes and sizes other than the preferred ellipse could be used, but this particular ellipse has been found to be useful. 
   The housing body  10  has an inlet cavity  12  that extends radially outwardly from the radially inwardly facing cylindrical surface  14  into the housing body  10  as shown in  FIG. 3 . The passage  15  extends tangentially from the inlet cavity  12  toward the passage  13 , which extends longitudinally through the housing body  10 . The passages  13  and  15  are in fluid communication with the inlet cavity  12 , and, in an operable configuration, with a source of fluent material, such as ground sausage. Thus, fluent material can be supplied to the chamber of the housing body  10  by conveying it through the passage  13 , through the passage  15  and then through the inlet cavity  12 . The inlet cavity  12  could alternatively be made up of a plurality of inlet cavities. This is not preferred but is a possible alternative to the preferred embodiment. 
   The housing body  10  also has an outlet cavity  16  that extends radially outwardly from the radially inwardly facing cylindrical surface  14  into the housing body  10  as shown in  FIG. 2 . The passage  17 , which extends tangentially through the housing body  10  and terminates in the flange  19 , is in fluid communication with the outlet cavity  16 . In an operable configuration, the flange  19  is connected to a tube or other conduit that connects to a food slicing machine, such as those machines sold by the J.E. Grote Company. Thus, through the conduit and the passage  17 , the outlet cavity  16  is in fluid communication with a destination of fluent material, such as a food slicing machine. Fluent material is thereby removed from the chamber of the housing body  10  by conveying it through the outlet cavity  16  and the passage  17 . The outlet cavity  16  could be made up of a plurality of outlet cavities. This is not preferred but is a possible alternative to the preferred embodiment. 
   The housing body  10  has a plurality of sub-chambers within the chamber. These sub-chambers are formed between the vanes  50  and  52 , the hub&#39;s radially outwardly facing surface and the radially inwardly facing cylindrical surface  14 . These sub-chambers can change in volume as the hub  30  is rotated, as in a conventional vane pump so that during a portion of each revolution of the hub each sub-chamber is increasing, during a portion of each revolution each sub-chamber is decreasing, and during a portion of each revolution each sub-chamber stays the same. This increasing and decreasing volume causes the hub to rotate as described next. 
   Each sub-chamber receives fluent material, such as ground sausage, through the inlet cavity  12  when the raw sausage is forced through the passage  13 . The sausage enters the sub-chamber under pressure, and an outward force is exerted by the sausage against all sides of the sub-chamber. Because the vane on one side of the sub-chamber has greater surface area than the vane on the opposite side, the outward force caused by the pressurized sausage exerts a net force on the hub  30  in one circumferential direction. This force causes the hub  30  to rotate. 
   As the hub  30  rotates, the sub-chamber being filled continues to be filled, and the next adjacent sub-chamber begins to be filled once its leading vane passes over the inlet cavity  12 . After the trailing vane of the first sub-chamber travels past the inlet cavity  12 , the first sub-chamber ceases to be filled, and the next adjacent sub-chamber is the only sub-chamber being filled with sausage under pressure, which continues the rotation of the hub  30 . 
   The rotation of the hub  30  drives the sausage in the sub-chambers around the hub to the opposite side of the radially inwardly facing cylindrical surface  14  where the outlet cavity  16  is formed. When the leading vane of the sub-chamber passes over the outlet cavity  16 , the sub-chamber begins to decrease in volume due to the shape of the radially inwardly facing cylindrical surface  14 , thereby forcing the sausage in the sub-chamber out of the sub-chamber into the outlet cavity  16 . This continues until the sub-chamber is substantially empty. The forcing of sausage or other fluent material into the chamber and forcing of sausage out of the chamber is a continuous process. 
   It is important to note that the sub-chambers are of consistent volume once they have been filled and before the sausage begins to be conveyed out of the sub-chamber. There is no substantial leaking of sausage from one sub-chamber to another, and there is no substantial difference in the volume of sausage in one sub-chamber and the volume of sausage of another sub-chamber during the same position of the sub-chamber in the revolution of the hub  30 . 
   These equal volume sub-chambers make the invention an effective flow divider when two or more such combinations of the housing body  10 , hub  30  and vanes  50  and  52  are drivingly linked together. Such a combination is shown in  FIGS. 12 to 14 . For example, the housing body  210  is shown in  FIG. 12  in a coaxial relation to the housing body  10  described above. The housing body  210  is substantially identical in all respects to the housing body  10 , although a person of ordinary skill will recognize that some modifications could be made to the housing body  210 . The housing body  210  has a hub  230  and vanes  250  and  252  mounted therein. The hub  230  is rotatably mounted in the housing body  210  in the same manner as described above for the hub  30  in the housing body  10 . 
   The housing bodies  10  and  210  are rigidly mounted together, preferably by screws, as shown in  FIG. 14 , or by any other preferably removable fastener, such as clamps or bands. As shown in  FIG. 3 , the integral machined tabs  22  and mating notches  24  which are preferably formed on opposite sides of all housing bodies, matingly engage to align the adjacent housing bodies to one another to accurately hold their coaxial relations and simplify assembly of the device. Conventional rubber O-rings  60  and  62  are inserted in grooves adjacent the radially inwardly facing cylindrical surface  14  and the passage  13 , respectively, in order to obtain a seal between the housing bodies. It is possible to weld or otherwise permanently fasten the housing bodies  10  and  210  together, but this eliminates the possibility of separating the housing bodies later for thorough cleaning. The wall  218  (not shown) of the housing body  210  is substantially identical to the wall  18  of the housing body  10 , and encloses the chamber of the housing body  10  at the side opposite the wall  18 . The end of the hub  30  seats against this wall  218 . 
   It is desirable in some circumstances to have a plurality of housing bodies  10 ,  210 ,  310  and  410  mounted together as illustrated in  FIGS. 13 and 14 . The number of housing bodies that can be mounted together is essentially unlimited. The housing bodies  310  and  410  are substantially identical to the housing bodies  10  and  210 , and include corresponding hubs, vanes, inlet and outlet cavities, and all other components that are combined with the housing bodies  10  and  210  as described above. These housing bodies  210 ,  310  and  410  have the flanges  219 ,  319  and  419 , respectively, which are in fluid communication with outlet cavities (not shown) in the respective chambers that are substantially identical to the outlet cavity  16 . In an operable configuration, the flanges are all connected to tubes or other conduits that connect the chambers to a food slicing machine. 
   When the housing bodies  10 ,  210 ,  310  and  410  are mounted together, their respective tabs and notches engage for alignment, and their respective hubs are also drivingly linked together. The linking of the hubs  30  and  230  will be described for illustrative purposes, with the understanding that a substantially identical link is used with the hubs in the housing bodies  310  and  410  and any other housing bodies that are mounted thereto. The tangs  38   a  and  39   a  extend longitudinally into the slots  238   b  and  239   b , which are substantially identical to the slots  38   b  and  39   b  in the hub  30 , when the housing bodies  10  and  210  are displaced longitudinally toward one another to mount the housing bodies  10  and  210  together. The tangs  38   a  and  39   a  are inserted longitudinally into the slots  238   b  and  239   b , and are engaged frictionally by the surfaces that define the slots to prevent any substantial relative rotational motion between the hubs  30  and  230 , but to permit longitudinal withdrawal. Therefore, when one hub is rotated, the other hub is rotated the same amount and in the same direction. The hubs  30  and  230  are, in effect, therefore a single rotating body. Many other equivalent means for drivingly linking the hubs will become apparent to the person of ordinary skill from the description. 
   Once the entire combination of housing bodies and their corresponding hubs and vanes are assembled into the combination shown in  FIG. 13 , the end caps  80  and  90  are attached at opposite ends. The end cap  80  is shown in detail in  FIG. 15 , and the end cap  90  is shown in detail in  FIG. 16 . The end caps  80  and  90  are preferably made of a food grade, low friction polymer, such as DELRIN. The end caps  80  and  90  are closures over the internal chambers of the housing bodies to prevent leakage of gases, liquids or the fluent sausage out of the housing bodies. 
   The end cap  90  is a solid, planar structure having an aperture  94  formed through it that terminates in a flange  92 . The flange  92  is on the side of the cap  90  that will be placed outside of the combination of housing bodies, and permits attachment of a tube or other fluent material-conveying conduit having a central passageway that aligns with the aperture  94 . The end cap  90  aligns with the adjacent housing body by receiving the housing body&#39;s tab into the notch  98 . Sausage, or other fluent material, is conveyed under pressure through the aperture  94  and into the passage  13  of the housing body  10  (see  FIGS. 1 and 3 ), which is in fluid communication with the substantially identical passages formed in the housing bodies  210 ,  310  and  410 , which align longitudinally with the passage  13  and the aperture  94 . Each housing body&#39;s passage is in fluid communication with its corresponding inlet cavity to permit sausage or other fluent material conveyed therethrough to enter the chambers of the respective housing bodies. The end of the longitudinal passage formed by the aperture  94  and the passages in the housing bodies terminates at the opposite end of the combination of housing bodies where the end cap  80  attaches. 
   The end cap  80  is a solid, planar structure having an aperture  84  formed through it that terminates in a flange  82 . The flange  82  is on the side of the cap  80  that will be placed outside of the combination of housing bodies, and is capped in a preferred embodiment, but can be used instead of the flange  92  if it is desired to attach the tube or other conduit from that side of the apparatus. This makes the apparatus reversible. Additionally, it is contemplated that if a large number of housing bodies are used, one might wish to supply fluent material to both ends of the apparatus to avoid “starving” some chambers. Still further, the flange  82  could be used to remove air from the system at startup. This is not necessary under normal operation with sausage, but could be desirable in the future, or when used with a different fluent material. 
   The cap  80  has a preferably circular recess  86  formed in the side that faces toward the housing  410  to which the cap  80  attaches. The recess  86  is slightly deeper than the length of the tangs  438   a  and  439   a  (not shown) formed on the hub  430  (not shown) mounted in the housing  410 , which hub and tangs are substantially identical to the hub  30  with tangs  38   a  and  39   a  shown in  FIG. 4 . Additionally, the recess  86  has a diameter slightly greater than the distance between the extreme radial edges of the tangs  438   a  and  439   a . In an operable position the recess  86  is aligned coaxially with the hub  430  with the tangs  438   a  and  439   a  inserted within the recess  86 . The recess  86  accommodates the protruding tangs that would otherwise be drivingly linked to an adjacent hub, and makes unnecessary the use of a different hub with no tangs. The cap  80  aligns with the adjacent housing body by inserting its tab  88  into the mounting body&#39;s notch. 
   When sausage is forced into the chambers of the housing bodies  10 ,  210 ,  310  and  410 , the hubs  30  and  230  (and the corresponding hubs within the housing bodies  310  and  410 ) rotate together and at the same rate described above in relation to the housing body  10 . Thus, the volume of sausage that enters the entire apparatus is divided between the chambers in the apparatus, and exits the chambers in equal volume streams. The combination of such housing bodies, hubs and vanes functions as a flow divider, inasmuch as there is one inlet for pressurized sausage (or other fluent material) to enter the combination, and each housing body has its own outlet that, due to the function of the drivingly linked hubs, meters out a volume of sausage that is equal at all outlets. The apparatus functions as a very effective flow divider that can have its inlet connected to a source, such as a sausage-making machine or pump, and each of its outlets connected to a destination, such as one lane of a sausage-slicing machine. In experiments, the invention has produced results varying between 0.06 to 0.08 ounces in weight between its outlet flow streams. 
   In the preferred embodiment described above, there is a source of fluent material, or possibly two sources of fluent material, that are forced into the apparatus, which divides the fluent material into a greater number of equal flow rate streams of fluent material. The number of sources is not critical, although in a preferred embodiment only one source exists, and the number of destinations is not critical. The apparatus operates to divide one or a small number of sources of fluent material into a greater number of equal volumetric flow rate streams of fluent material. Alternatively, the relative sizes of the chambers can be modified to have unequal volume flow rates at different outlets, if desired. 
   The apparatus described above can also operate in reverse by forcing fluent material under pressure into the outlet cavities. This causes the hubs and vanes to rotate backward at the same rate and force the fluent material out the inlet cavities to be combined in the single passage and flow out of the passage as a single stream. This may be desirable, for example, if one wishes to combine various types of fluent material from a plurality of sources into a single stream of fluent material. When the apparatus is operated in this manner, it will be noticed that the inlets and outlets have the opposite function than their names imply, and therefore the names used in the description above for the flow divider can appropriately be changed. 
   The embodiments described above permit detachment of all components of the present invention from one another for cleaning. Additionally, each of the hubs, housing bodies and vanes is substantially identical to, and therefore interchangeable with, every other hub, housing body and vane. This makes re-assembly after cleaning very easy. Of course, it would be possible to make some of the parts permanently attached, but this could result in more difficulty in cleaning. Nonetheless, such embodiments fall within the scope of the invention. For example, the housing bodies could be a single housing that is divided into two chambers, each accessible from an opposite end of the housing. Thus, it will be seen that the housing can be made up of multiple housing bodies, each having at least one chamber, or one housing body with at least two chambers. The number of “modules” of housing bodies, vanes and hubs is virtually unlimited, and could range from two to any number greater than two. 
   While certain preferred embodiments of the present invention have been disclosed in detail, it is to be understood that various modifications may be adopted without departing from the spirit of the invention or scope of the following claims.

Technology Category: 4