Abstract:
In many fields, such as manufacturing and mining, compressed air is used as a power source for industrial equipment, hand power tools, etc. Extensive compressed air systems are installed in these environments to supply compressed air where it is needed. In mining, extensive belts are frequently used to move mined material. Idler rollers are located intermittently along these belts. Embodiments of the present invention include compressors located within these idler rollers. As the belt moves and causes the roller to turn, a compressor within the roller generates compressed air. Because the belt moves nearly continuously, but the compressed air may not be consumed continuously, the air will be vented periodically. Embodiments of the present invention use these vents to clean the filters for the system. Also, some embodiments of the compressor may be produced using a laminated, or stacked, method.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application 61/842,522 filed on Jul. 3, 2013. The entirety of U.S. Provisional Application 61/842,522 including both the figures and specification are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The several embodiments of the current invention relate to remote and local supplies of compressed air. In particular, the several embodiments of the current invention relate to remote compressors driven by conveyor belts to supply compressed air at remote locations. 
       BACKGROUND OF THE INVENTION 
       [0003]    Compressed air is used extensively to power tools and mechanical systems. For example, manufacturing plants have entire systems of compressors, surge tanks, and pipes located throughout them in order to provide supplies of compressed air to power air cylinders in manufacturing equipment, hand tools powered by compressed air, air-over-oil hydraulic systems, nozzles for cleaning equipment, etc. The piping is equipped for quick connect to the compressed air system and this includes “drops” throughout the plant where hoses drop from overhead pipes to supply compressed air at needed locations. In manufacturing plants, these systems can be built using generally centralized compressors and tanks with statically located pipes, hoses, and access points. 
         [0004]    Underground mining also extensively employs hand tools and equipment powered at least partially by compressed air. However, because of the nature of underground mining, large centrally located air compressors and static piping infrastructure are not as practical. As the desired material is removed from the mines, the locations of high activity in the mines move. Additionally, the mining environment is a difficult environment to install elaborate infrastructure, such as static piping systems. Flexible hoses are not a desirable substitute for rigid piping systems since mining environments are very harsh with the coming and going of equipment posing risks of piercing and cutting the hoses, while equipment or debris could pinch off the hoses. Loss of air pressure for equipment relying on compressed air could have drastic consequences. There remains a need for means of providing compressed air to remote locations in underground mines as well as other above ground applications. Embodiments of the present invention have applications in other environments beyond mining, as well. 
       DESCRIPTION OF RELEVANT ART 
       [0005]    U.S. Pat. No. 4,345,886 by Nakayama, et al discloses a rotary compressor for compressing fluid. A housing having a cylindrical internal cavity is provided with vanes and delivery ports. A rotor is rotatably mounted in the housing. The rotor has a portion for making a sealing contact with the inner peripheral surface of the housing. The rotor has a suction chamber formed therein. The number of the vanes is greater by 1 (one) than the number of the sealing contacts between the rotor and the inner peripheral surface of the housing. At least one suction port is formed through the wall of the rotor, so that the fluid in the suction chamber may be sucked into the working chamber defined by the vanes, rotor and the housing. The suction port is so located that, when a working chamber has been expanded to its maximum volume, the suction port is positioned between the vane located at the leading side of the working chamber as viewed in the direction or rotation of the rotor and the sealing portion closer to the vane. The fluid compressed in the working chamber is delivered to the outside of the housing through the delivery ports. 
       SUMMARY OF THE INVENTION 
       [0006]    There are many types of air compressors and pumps. Each generally comprises a housing providing a fixed or grounded structure, moving elements within the housing to create changing volumes within the housing, and an input power shaft connected to the moving to power the moving elements within the housing. Embodiments of the present invention invert the arrangement of prior art pumps. The shaft connected to the elements internal to the housing is fixed, while the housing is allowed to turn. The housing is formed to have a cylindrical outer surface so that the housing itself can be turn by a belt. 
         [0007]    As discussed above in the background section, compressed air systems are a common power system in industrial settings, and this includes mining operations. Conveyor belts are commonly featured in mining operations to move the mined material about. This includes moving the extracted material extensive distances underground from the location where it is mined, moving the material out of the mine, and moving the material along extensive distances above ground. These belts occasionally run over idler rollers which are located in multiple places along the length of the belts. The idler rollers are mounted at shafts protruding from each end of the roller, and the belts roll over them. Bearings can be used to reduce the drag on the rollers and belts. These bearings may be mounted about the ends of the shaft where the roller is mounted, or the bearings can be located within the roller between the shaft and the body of the roller. 
         [0008]    Embodiments of the present invention utilize these idler pullers and the movement of the belt to provide localized sources of compressed air. An air compressor is located within an idler roller and as the belt passes over a roller and forces the idler roller to turn, the air compressor within the roller is powered and compressed air is generated. The compressed air is conducted from the roller via piping, valving, etc. 
         [0009]    A common type of compressor is a vane compressor. The most common type of vane compressor has a cylindrical housing closed at each end with an opening for a shaft in at least one end. This opening for a shaft is eccentrically located and a shaft passes through the opening to drive a cylindrical internal compressor member. This cylindrical internal compressor member, or rotor, has slots in it around its outer radial surface, and these slots carry vanes. Springs located within the slots bias the vanes outward from the slots, and the vanes protrude from the surface of the rotor. With the eccentric location of the rotor, the rotor is closer to the internal surface of the housing on one side than it is on the other. The vanes in the rotor are long enough that they can maintain contact with the internal surface of the housing, including when the radial surface of the rotor is further away from the internal surface of the housing. Individual volumes are defined between each set of adjacent vanes, the rotor surface, the interior surface of the housing, and the endplates enclosing the housing. These volumes are larger where the rotor surface is further away from the housing and smaller where the rotor surface is closer to the housing. 
         [0010]    When the rotor is turned, these volumes alternate between their maximum volume and minimum volume as they travel about the housing. When the volumes are increasing in size, ports in the housing allow fluid to flow into the housing and fill the volumes, while other ports in the housing allow fluid to exit the volumes and the housing, when the volumes are decreasing. This creates the effect of moving fluid through the housing. If the fluid is compressible, the mechanism may be called a compressor. If the fluid is incompressible, the mechanism may be called a pump. 
         [0011]    Embodiments of the present invention move the vanes to slots in the interior surface of the housing and fix the interior element. The interior element, which would normally be a rotor, becomes a stator, and the housing becomes a rotor. The housing is turned about the interior element by the belt being pulled over the housing. The vanes carried by the rotating housing maintain contact with the interior element to create rotating volumes. 
         [0012]    In some embodiments, the interior element is eccentrically located within the rotating housing. In these embodiments, the shaft on which the interior element is mounted is eccentrically located with respect to the interior element so that the shaft can be concentrically located with respect to the rotating housing. The rotating housing rotates about the shaft which is mounted and fixed in the same mounts that a regular inert idler roller is mounted. Because the interior element and the shaft are fixed in these embodiments, many of these embodiments will provide for fluid intake and exit through the shaft. Some embodiments may employ ports through side plates enclosing the ends of the housing. However, these endplates need to be fixed and exposed to access for piping. 
         [0013]    Other embodiments of the invention may employ an interior stator element that is elliptical but concentrically fixed within the round housing. Each end of the elliptical stator makes a sealed contact line with the interior surface of the housing. As with other embodiments employing vanes, the vanes are carried by the housing which rotates about the stator. As the cylindrical rotor is rotated about the stator by a belt, the vanes in the rotor are moved along the surface of the stator. As a vane approaches a contact line between the stator and housing, the volume between that vane and the contact line decreases, and fluid is forced from that volume. Ports allow the intake and exit of fluid. 
         [0014]    Appropriate fittings and piping leading from the shaft of the idler roller allows compressed air to be directed from the roller. The idler roller can be located anywhere an idler roller would be typically mounted and provides compressed air at local and remote locations without the need to install extensive compressed air systems. The power to generate the compressed air comes from the belt moving the material and is ultimately at a central source driving the belt. 
         [0015]    In the prior art, there are also examples of vane compressors wherein the vanes are located in the outer housing instead of being located in the interior element. In at least one prior art reference the rotor has an elliptical shape and porting within it to allow fluid flow through the device. However, in this reference, the rotor is the interior element and it is the element that is turned by an external shaft. 
         [0016]    In the locations where a belt is located, it is likely that the environment will be harsh, and the air will be full of contaminants and particulates. Because of this, filters typically associated with air systems will require more frequent maintenance or changing. However, the present invention incorporates a mechanism for decreasing the frequency of maintenance required. Although the belts in these environments run nearly continuously, the need for compressed air may not be a continuous need. This means that surge cylinders, or tanks, charged by the compressed air generators in the rollers will be fed compressed air even when no demand is placed on them. As the surge tanks reach the desired pressure, or rated limits, a poppet valve will allow compressed air to exhaust from the tanks This exhaustion of compressed air will occur periodically because the air compressor will run continuously when the belts are running 
         [0017]    Embodiments of a system incorporating the roller compressor employ this periodic release of air to clean the air filters for air intake for the compressor. The air exhausted through the poppet valve is directed through a line back at the air filter taking air into the compressed air system. This surge of air can be used in several ways. The surge of air can “shake” the filter element, the surge of air can be directed in the opposing normal flow of the filter to back-flush the filter, and/or the surge of air can be directed along the intake face of the filter to flush debris from the face. This periodic cleaning of the filter with the vented excess air decreases the frequency with which the filters need to be cleaned or replaced. 
         [0018]    When an embodiment of the compressor of the present invention uses a vane style of compressor, it may be desirable to employ alternative means of constructing the rotor portion of the compressor. Creating a series of deep slots in the internal volume of a solid mass requires an expensive machining process. Certain embodiments of the present invention employing a vane compressor will therefore have the internal contour of the rotating housing constructed from a series of stacked plates having the desired contours and the desired slots in the plates. With a stack of plates, slots in each individual plate add up to a linear slot in the internal volume of the cylindrical housing. In addition to the avoidance of machining extensive slots into a solid mass, the stackable plates may have other slots where one or more plates combine to create ports and ducts to facilitate the intake and outflow of air from the air compressor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Additional utility and features of this invention will become more fully apparent to those skilled in the art by reference to the following drawings, wherein all components are designated by like numerals and described more specifically. 
           [0020]      FIG. 1  is an end view of an embodiment of the invention with an end view of the stator and sectional end view of the rotor. 
           [0021]      FIG. 2  is an end view of an embodiment of the invention. 
           [0022]      FIG. 3  is a side section view of the embodiment shown in  FIG. 2  sectioned at the line shown in  FIG. 2 . 
           [0023]      FIG. 4  is an exploded side view of the embodiment in shown in  FIG. 3 . 
           [0024]      FIG. 5  is a perspective view of a conveyor with an embodiment of the invention installed as an idler roller and showing accompanying elements for the compressor. 
           [0025]      FIG. 6  is a perspective view of a conveyor with an embodiment of the invention installed in a different idler roller location than that of  FIG. 5  and showing accompanying elements for the compressor. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0026]      FIG. 1  is an end view of an embodiment of a compressor  10  according to the current invention with an end view of stator  20  and sectional end view of rotor  40 . Stator  20  terminates in shaft  22  for mounting compressor  10  under a belt. Shoulder  24  on stator  10  provides a surface for the inner race of bearing to contact. Cam  26  of stator  20  is eccentric to shaft  22  and is therefore eccentrically located within rotor  40 . 
         [0027]    Rotor  40  is concentric with shaft  22  of stator  20  and carries vanes  42  about stator  20  as rotor  40  turns. Vanes  42  are located in slots  44  in rotor  40  and are biased outwardly from slots  44 , but radially inward toward cam  26 . Vanes  42  are biased outward from slots  44  by suitable biasing elements. These biasing elements may be springs, elastomeric pads, etc. In  FIG. 1 , springs  43  are shown in two of slots  44  in rotor  40 . Casing  46  around the outside of rotor  40  is contacted by a belt and turned by the belt to rotate rotor  40  about stator  20 . 
         [0028]    Vanes  42  maintain contact with surface  28  of cam  26  as they are moved about cam  26 . Volumes  48  are defined between each set of two vanes  42 , cam  26 , interior surface  50  of rotor  40 , and endplates that enclose the interior of rotor  40 . Because of the eccentric location of cam  26  within rotor  40 , the distance between cam  26  and interior surface  50  of rotor  40  varies about cam  26 . This means the capacity of volumes  48  vary between a maximum and minimum as they rotate about cam  26 . If a fluid is allowed into volumes  48  at their maximum and allowed out of volumes  48  as they decrease, fluid is moved through compressor  10 . 
         [0029]      FIG. 2  is an end view of an embodiment of a compressor  10  according to the present invention. Around the outside of rotor  40 , casing  46  is visible, while endplate  52  encloses the inside of rotor  40 . Shaft  22  and shoulder  24  of stator  20  are visible in  FIG. 2  as well. Bearing  60  couples stator  20  to rotor  40  Inner race  62  of bearing  60  fits on shoulder  24  of stator  20 , while outer race  64  of bearing  60  fits into flange  54  of endplate  52 . Seal  66  of bearing  60  keeps contaminants out of bearing  60  and rotor  40 . Bolt heads  56  around endplate  52  belong to bolts  58  which keep rotor  40  assembled. Returning to  FIG. 1 , bolts  58  may be seen in section view. 
         [0030]      FIG. 3  is a side section view of the embodiment shown in  FIG. 2  sectioned at the line shown in  FIG. 2 . In  FIG. 3 , stator  20  can be seen spanning from left to right through rotor  40 . Inner races  62  of bearings  60  fit on shoulders  24  of stator  20 , while outer races  64  of bearings  60  fit into flanges  54  of endplates  52 . Rollers  68  in bearings  60  are shown as spherical in  FIG. 3 , but could be cylindrical or tapered depending on the specific application of the compressor and the expected loads on bearings  60 . Apertures  59  in endplates  52  have a small clearance around shoulder  24  of stator  20  to allow rotation of rotor  40  with respect to stator  20 . 
         [0031]    As mentioned above, to move fluid through compressor  10 , the fluid must be allowed to enter and exit volumes  48  within compressor  10 . To that end, blind holes  30  and  31  extend from the ends of shafts  22  into the interior of stator  20 . Ports  32  and  33  extend from the surface  28  of cam  26  to blind holes  30  and  31  respectively. Ports  32  and  33  act as intake and exhaust ports and are positioned generally radially out of phase with each other so that direct communication between them via a single volume  48  is not possible. 
         [0032]    While the section view of  FIG. 3  gives the impression that ports  32  and  33  are single ports, they may actually be a series of ports arranged through an angle about cam  26 . This would allow intake into volumes  48  through more of the roughly 180° during which volumes  48  is increasing and allow exhaust from volumes  48  through more of the roughly 180° during which volumes  48  are decreasing as rotor  40  turns. 
         [0033]    In  FIG. 3 , it can be seen that internal body of rotor  40  is comprised of a stack of plates  57 . Each plate  57  has a series of radial slots in them so that when stacked, plates  57  form a cylinder with interior surface  50  and slots  44  extending from the interior surface  50  into the body of rotor  40 . Plates  57  also have apertures through them spaced radially so that bolts  58  may pass through in order to hold rotor  40  together. The stacked method of constructing rotor  40  avoids the requirement of machining operations to mill out material to form slots  44  in a single cylindrical mass. The stacked assembly also provides a degree of modularity. Compressors of different capacities can be assembled by changing the number of plates. Other elements, such as vanes  42  would have to be changed as well. 
         [0034]      FIG. 4  is an exploded side view of the embodiment in shown in  FIG. 3 . In  FIG. 4 , casing  46  is at the left with stator  20  still in place within it. Other elements of compressor  10  are exploded out to the right. Just to the right of stator  20  are plates  57  which combine to form the interior body of rotor  40 . Only a few plates  57  are shown in  FIG. 4 . Enough plates  57  are required to create a stack equivalent to the length of vanes  42  which are to the right of plates  57 . 
         [0035]    In  FIG. 4 , two vanes  42  are shown from the side, while one vane  42  is shown from the back. Additional vanes would be located between the vanes  42  shown, but they are omitted in  FIG. 4 . Springs  43  are located at the back of vanes  42  are serve to bias vanes  42  outward from their slots. Other biasing elements such as elastomeric pads could be used as well as other types of springs, such as leaf springs. 
         [0036]    Above and below vanes  42  in  FIG. 4  are keys  45 . Keys  45  fit into slots on the inner diameter of case  46  and into notches in plates  57 . This fixes the stack of plates  57  with respect to casing  46  so that all of rotor  40  turns as a unit with respect to stator  20 . Other methods for securing plates  57  within casing  40  may also be used. For example, plates  57  may have tabs on them which match with slots on the inner diameter of casing  40 . 
         [0037]    Endplate  54  is displaced out to the right of vanes  42  and keys  45 . Further to the right, bearing  60  fits into endplate  52  and around shaft  22 . Bearing  60  allows rotor  40  to turn about stator  20 . Bolts  58  pass through endplate  54  through plates  57  and on into its complementary endplate  54  at the opposite end of rotor  40 . 
         [0038]      FIG. 5  is a perspective view of a conveyor  80  with an embodiment of the invention installed as an idler roller, i.e. compressor  10 , and showing accompanying elements for compressor  10 . Piping  71  is connected to each end of compressor  10 . Piping  71  connects to stator  20  which has apertures intake and exhaust at opposing ends. Piping  71  runs to cabinet  70  which encloses other elements of the air system. Filter  72  on the front of cabinet  70  removes contaminants from the air as it is taken into the system. Tank  73  stores compressed air. The pressure allowed to develop in tank  73  is controlled by a regulator located in cabinet  70  and not shown in  FIG. 5 . Because compressor  10  will be operating whenever conveyor belt  80  is moving, the regulator in cabinet  70  is especially important to avoid excessive pressure build up in the system. Fitting  74  with hand valve  75  extending from the top of cabinet  70  provide a coupler  76  to connect to the compressed air system provided by compressor  10 , cabinet  70 , and tank  73 . 
         [0039]    Cabinet  70  can contain other elements of the system such as a lubricator and self-cleaning features. The lubricator adds a small amount of lubrication to the air as it is taken in and proceeds to the compressor  10 . The air carries the lubrication into compressor  10  to introduce lubrication into the internal workings of compressor  10 . Conveyors such as conveyor  80  operate in remote areas and compressor  10  is intended as a remote source of compressed air. Because compressor  10  runs continuously with conveyor  80 , the regulator in cabinet  70  will periodically vent tank  73 . The vented air can be used to clean filter  72  in various ways. The air can power a shaker, it can be directed back through the filter, or those and/or other actions can be combined. 
         [0040]      FIG. 6  is a perspective view of conveyor  80  with an embodiment of the invention installed as a different idler roller than that of  FIG. 5  and showing accompanying elements for the compressor. Similarly to  FIG. 5 ,  FIG. 6  shows tank  73  and cabinet  70  and connecting piping  71 . Being a larger idler roller, compressor  10  in  FIG. 6  has the opportunity for a higher volume compressor than that of  FIG. 5 . Alternatively, compressor  10  may only have working elements in a segment of the roller. Because the location in  FIG. 5  only supports a segment of the belt, compressor  10  in  FIG. 5  is more accessible from an installation and maintenance perspective than compressor  10  in  FIG. 6 . 
         [0041]    While several embodiments of a compressor in an idler have been discussed above in the specification, it should be born in mind that these are not the only embodiments encompassed by the ensuing claims. Other compressor configurations could be fit within the idler roller and powered by the turning of the roller by a belt. Neither should the abstract or drawing figures be considered limiting. Rather the abstract is for overview purposes only and the drawing are to provide ease of understanding example embodiments. Additionally, although reference was made to the mining industry, it should be readily apparent that embodiments of the present invention are not limited application in the mining field.