Abstract:
A vane compressor has a plurality of vanes that are radially translatable and have outer ends. The vanes create zones between each pair of adjacent vanes, each zone having a given area. The vane compressor also has an axis about which the vanes rotate and an outlet for expelling compressed fluid. A first zone immediately following a second zone, which is in register with the outlet, has the same area as the second zone.

Description:
BACKGROUND 
       [0001]    This application relates to vane compressors, and more particularly to a valveless vane compressor. 
         [0002]    Vane compressors compress fluids, such as gas, and are well known in the art. A vane compressor may have internal disk in which a plurality of vanes are free to move in and out of the disk. The vanes follow an outer circumference and take in fluid when the vanes are extended from the disk, and compress the fluid as the vanes follow the circumference and contract thereby lessening the area in which the fluid is entrapped. The compressed fluid is pushed out of a fluid outlet. To prevent the fluid from back flowing into a vane compressor, valves are typically disposed within the fluid outlet to prevent such back flow. As the compressor drive shaft rotates, the vanes slide in and out to make contact with the compressor wall. Fluid enters at the largest opening and the compressed fluid discharges from the smallest opening. Vane compressors may utilize a centered drive shaft and a shaped outer surface or an offset drive shaft and a circular outer surface. 
       SUMMARY 
       [0003]    According to an example disclosed herein, a vane compressor has a plurality of vanes that are radially translatable and have outer ends. The vanes create zones between each pair of adjacent vanes, each zone having a given area. The vane compressor also has an axis about which the vanes rotate and an outlet for expelling compressed fluid. A first zone immediately following a second zone that is in register with the outlet has the same area as the second zone. 
         [0004]    According to a further example disclosed herein, a method of compressing fluid is provided. The method includes the steps of inletting a fluid having a first area; compressing the fluid by decreasing the first area to a smaller second area; rotating the second area to a first zone immediately leading a second zone having an outlet; rotating the second area to the second zone; and outletting the fluid from the second zone to reduce backflow from the outlet. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows. 
           [0006]    The FIGURE shows a schematic view, partially in phantom, of a vane compressor as described herein. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0007]    Referring to the FIGURE, a vane compressor  10  is shown. The vane compressor  10  is of the balance type, however, one of ordinary skill would recognize that this teachings may be usable in other types of vane compressors, balanced or non-balanced, and with central off center drives or centered drives, etc. The vane compressor  10  has a disk  15  that rotates about axis  20 , a cam surface  25 , slots  30 , vanes  35 , inlets  40  and outlets  45 . The dimensions shown in the FIGURE are exaggerated for ease of observation. As shown herein, the vane compressor  10  rotates in a clockwise direction. 
         [0008]    Within the disk  15 , the vanes  35  translate during rotation of the disk  15  within the slots  30  so that there is contact between the cam surface  25  and the vanes  35 . The vane compressor  10  is a balanced vane compressor and has two inlets  40  and two outlets  45  distributed around and through the cam surface  25 . Though fourteen vanes  35  are shown herein, one of ordinary skill will recognize that other numbers of vanes  35  are utilizable herein. 
         [0009]    As the disk  15  and the vanes  35  rotate, areas of variable size are created between the vanes  35 . As shown in the FIGURE, there are  14  zones designated from A to N as will be discussed herein. 
         [0010]    Zones A, B and C, which all have the same or similar area, form an outlet zone O. Zone B is in register with an outlet  45  of outlet zone O. Similarly, zones H, I and J, which all have the same or similar area, form a similar outlet zone P where zone I is in register with outlet  45  of outlet zone P. In outlet zone O and outlet zone P, the vanes  35  in register therewith are in a stowed position within the relevant slots  30  as they follow first contour  50  in the cam surface  25 . The first contour  50  of the cam surface  25  in outlet zone P has a constant length radius  55  emanating from axis  20 . The area of zones A, B, and C, and the area of zones H, I, J, is minimized and carry compressed fluid, such as air, therein. 
         [0011]    Zones D and K form compression zones as the variable vanes  35  move from an extended position relative to the slots  30  to a stowed position while following a diminishing second contour  60  thereby limiting (e.g., diminishing) the area of zones D and K to the same area shown in zones A, B and C forming outlet zone O and zones H, I and J forming outlet zone P respectively. The diminishing second contour  60  has a radius  65  emanating from axis  20  that diminishes from a length of a radius  70  in zone E to the same length of radius  55  as in outlet zones O and P. 
         [0012]    Zones F and E and Zones M and L all have the same or similar area and a constant radius  70  following third contour  75  of the cam surface  25 . 
         [0013]    Zones F and G, and N and M are each in register with a fluid inlet  40 . Zones N and G represent expansion areas where the vanes  35  move from a stowed position to an extended position to allow fluid to move therein and the fourth contour  80  which attaches the first contour  50  to the third contour  75 . Zones E and L each have the same area as the preceding zones M and F to prevent back flow of fluid from zones E and L to the zones M and F respectively because the pressure in those zones are the same. Zones N and G have an extending arc  85 . 
         [0014]    As previously mentioned, zones K and D compress in area, thereby compressing the fluid therein, so that the zone C and the corresponding zone J have fluid at the proper pressure to export the pressurized fluid through the outlets even though zones C and J do not align with an outlet  45 . If the zones C and J are not fully compressed until they reach zones I and B, then as the vane between B and C or I and J passes the outlet  45  there may be back flow into zones C or J. As zone C moves to zone B and zone J moves to zone I though it is clear that the pressure of the fluid is proper to outlet through the outlets  45  without significant backflow into the zones I or B. By waiting another zone to expel the fluid compressed in zones C or J, the two aft vanes in zones O and P, in essence form a seal to reduce back flow. 
         [0015]    Waiting a zone to export the fluid through an outlet  45  after the fluid is compressed, allows a vane compressor  10  to be built without valves for preventing back flow. Similarly, zones A and H are also maintained at the same area as zones B and I, respectively. If zones A and H were allowed to expand in area by allowing the vanes  35  to move outwardly along the cam surface  25  in zones A and H, the drop in pressure in those zones may pull fluid from an outlet  45  through zones I and B respectively causing undesirable back flow from an outlet  45 . By waiting a zone, the two forward vanes and the two aft vanes in zones O and P, in essence form a seal to reduce back flow. As a result, by extending the vanes in zones N and M a full zone past an outlet  45 , a backflow prevention valve at an outlet  45  is unnecessary. 
         [0016]    Functionally, by keeping the area of zones A, B and C substantially constant as they create outlet zone O can prevent the need for back flow valves (not shown). The area in those zones is kept substantially constant herein by maintaining the substantially constant arc in the first contour  50  of the cam surface  25  in those zones. This is also true in outlet zone P which includes zones H, I and J. 
         [0017]    Similarly, vanes surrounding zones L and E are kept at a substantially constant distance from the axis  20  to the cam surface  25  as the immediately preceding zones M and F which are in register with the inlets  40 . This prevents back flow of fluid as it is compressed in zones K and D to reduce back flowing through the inlet  40  and wasting energy of compressing the fluid. 
         [0018]    Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in the FIGURE or all of the portions schematically shown in the FIGURE. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments. 
         [0019]    The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.