Abstract:
An improved rotary air lock feeder. The improved device includes a cylinder having a central axis. A plurality of vanes extending radially outward to rotate in the cylinder about the axis. A hopper communicates with the cylinder through an inlet located in an upper portion of the cylinder. A pair of offset openings extend from the upper portion of the cylinder along each side of a vertical plane extending from the axis. The offset openings communicate with the cylinder to intermittently provide inter-chamber communication at each said offset opening.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates to rotary air lock feeders. This invention more particularly pertains to discharging materials such as insulation in a relatively continuous and even manner.  
         BACKGROUND OF THE INVENTION  
         [0002]    Rotary air lock feeders typically include a hopper mounted over a cylinder. Material placed in the hopper falls through the hopper down into the cylinder. The material is gravity fed down to a rotor within the cylinder. The rotor has multiple vanes which revolve about an axis in the center of and extending along the length of the cylinder. The material falls between two adjacent vanes that form a revolving chamber. At least four vanes are required to hermetically isolate the hopper from discharge pressure. The cylinder also includes opposing end walls which form mutually aligned inlet and outlet ports. High pressure air passes through the chamber and discharges the material through the outlet port.  
           [0003]    Rotary air lock feeders are distinguishable from metering valves because metering valves do not include blowers. In other words, the material passing through metering valves typically passes through a slot running at the bottom of the entire length of the cylinder dependent entirely on gravity, whereas the material passing through a rotary feeder passes through a port at the end of a chamber in an air-train moving from the inlet port to the outlet port and into a hose that conveys the material to a point of application.  
           [0004]    Numerous attempts have been made to create a better rotary lock feeder. For example, the rotor might be made to rotate faster to discharge more material but eventually the rotor will reach a point where it spins so rapidly that the material cannot fall in. A longer feeder might be made to accept larger amounts of material to increase the rate of flow of material but they tend to clog and bring the flow to a stop.  
           [0005]    In known rotary air-lock feeders, the material then falls into a worm conveyor which is in a trough at the bottom of the hopper. The worm conveyor follows only a portion of the length of the feeder. The remainder includes a multi-vane rotor which substantially corresponds with the length of its cylinder. The multi-vane rotor deflects the material down into fast rotating times within a drop box beneath the hopper in which tines will further separate the material and then allow it to drop into the cylinder.  
           [0006]    Brands of fiberglass insulation differ according to weight and compressibility. Some insulation bales break up freely and expand greatly. Others have to be pulled apart and lie flat when separated. Bales of material are dropped into the hopper where paddle wheels in the hopper separate and chew it up.  
           [0007]    Light weight, highly compressible material, like some new makes of insulation, expands too greatly to fall quickly into the conveyor of these known machines. The conveyor cannot attack the insulation while it is in large, dense chunks. Rather, it moves light, small, separated bundles of insulation that settle out and fall into it. Consequently, the known machines are slow with this kind of material.  
           [0008]    Heavy, dense insulation that is manufactured so as not to expand greatly falls more quickly in known machines. The material, however, accelerates the time to failure of drive train components, feeder seals and rotating elements.  
           [0009]    Typically, known feeders have discharge ports which permit gravity to facilitate the movement of the material into the region between the ports rather than permit the speed of rotation of the vanes in the cylinder to introduce the material between the ports, limiting the length of a feeder and thus its capacity and speed. Also, these known feeders often fail to pneumatically isolate the high pressure of the air-train between the ports from the hopper. Escaping air often blows back into the hopper, interfering with and slowing the passage of material from the hopper into the cylinder.  
           [0010]    It is the provision of a new feeder to overcome these problems associated with known rotary air-lock feeders that this invention is primarily directed.  
         SUMMARY OF THE INVENTION  
         [0011]    The present invention solves the above-identified problems by providing an improved rotary air lock feeder. The present invention seeks to provide efficient discharging of various types of material, while satisfying the need to discharge the material in a relatively continuous and even manner.  
           [0012]    Generally described, the present invention includes a rotary air lock feeder for delivering a material, such as insulation, in substantially an even and continuous manner. The feeder includes a cylinder having a central axis. A multi-vaned rotor is rotatably positioned within the cylinder so that the vanes of the rotor extend radially outward from its axis of rotation which is the center of the cylinder. A hopper communicates with the cylinder through a slotted inlet located in an upper portion of the cylinder for its entire length. A pair of slotted openings offset on each side of the hopper extend along the length of the cylinder.  
           [0013]    In accordance with one embodiment of the present invention, the feeder includes a pathway for air at the entrainment pressure from the interior and exterior of the feeder without passing through the outlet port or back through the hopper. The pair of offset openings allow air pressure to escape without going into the hopper where it would interfere with the fall of material.  
           [0014]    In accordance with another embodiment of the present invention, to control the introduction of material without significant interference from gravity, the outlet port in the end of the cylinder is defined by outermost and innermost edges defined by increasing and decreasing radii, respectively, relative to the axis of rotation which is the center of the cylinder.  
           [0015]    In accordance with another embodiment to handle extreme kinds of material, the present invention includes a manner by which the exposure of the multi-vane rotor in the lowermost portion of the hopper may be increased or decreased to insulation by raising or lowering its relative position to the sloped surface of the hopper.  
           [0016]    The foregoing has outlined rather broadly, the more pertinent and important features of the present invention. The detailed description of the invention that follows is offered so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter. These form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the disclosed specific embodiment may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is front cross-sectional view of one embodiment of the rotary air lock feeder of the present invention.  
         [0018]    [0018]FIG. 2 is a close-up view of the path materials take while passing through the rotary air lock feeder of FIG. 1.  
         [0019]    [0019]FIG. 3 is a front cross-sectional view of an alternative embodiment of the rotary air lock feeder of the present invention.  
         [0020]    [0020]FIGS. 4 and 5 illustrate side perspective views of the feeders of FIGS. 2 and 3, respectively.  
         [0021]    [0021]FIGS. 6 and 7 illustrate different positions of the rotor vanes relative to the port in the metering chamber according to the present invention.  
         [0022]    [0022]FIG. 8 is an orthographic projection showing a conduit that adapts the shape of the material outlet port to a cylinder for insertion into a hose-pipe.  
         [0023]    [0023]FIG. 9 is an end view showing one embodiment.  
         [0024]    [0024]FIG. 10 is a perspective view of a rotor showing an alternative embodiment.  
         [0025]    Similar reference characters refer to similar parts throughout several views of the drawings.  
     
    
     DETAILED DESCRIPTION  
       [0026]    Referring now to the drawings in which like numerals indicate like elements throughout the several views, FIG. 1 illustrates an exemplary embodiment of a rotary air lock feeder  10 . Generally described, the rotary air lock feeder  10  includes a cylinder  12  having a circular interior sidewall and opposing end walls  14  (FIGS. 4 and 5). The cylinder  12  and associated parts described below are sometimes referred to as constituting a feeder. One of the end walls  14  defines an outlet port, as best shown in FIGS. 2 and 3, for discharging the material from the feeder  10  in the desired manner. The outlet port is described in greater detail below. A hopper  16  is positioned above the chamber  12  to direct material into a slotted opening in the top of the cylinder  12 . Preferably, the cylinder  12  is as long as the hopper  16  (FIGS. 4 and 5). The upper portion of interior walls of the hopper  14  may be vertically oriented or instead converge into the opening in the cylinder  12 .  
         [0027]    During the operation of the present invention, particulate material is fed into the top of the hopper  16  and the material gravitates into the cylinder  12 . The paddle wheel  22  propels and separates large pieces of material into a multi-vane rotor  24 . Its exposure may increased or decreased by raising or lowering its relative position to the sloped surface of the hopper. The high speed multi-tine rotor  20  separates the material and deflects it into the cylinder  12 . The rotors  20 ,  24  and  22  may operate at independent speeds and direction. Preferably, the lowermost rotor  20 , the one with multiple tines, rotates significantly faster than the other rotors positioned above it.  
         [0028]    The reversible direction of one or more of the paddle wheels or multi-vaned rotors facilitates the use of different types of material through the hopper  16  and into the cylinder  12 . As shown in FIG. 1, the multi-vaned rotor  20  and paddle wheel  22  rotate in a counter-clockwise direction while the center multi-vaned rotor  24  may operate in either direction. Please note that in the present invention, no worm conveyor is required which, therefore, allows the hopper  16  and the cylinder  12  to be substantially the same length, namely longer than a bale of material, which is approximately 44 inches.  
         [0029]    Also, as best shown in FIGS. 2 and 3, the lowermost portions  28  of the sidewalls of the hopper  16  are preferably parallel, but may pivot at their tops or be flexible so that when the vanes in the cylinder  12  pass the distal lower ends  29  of the lowermost portions  28 , greater clearance may be provided and material that might become impinged between the distal ends  29  and the cylinder  12  might be brushed away. FIG. 2 illustrates the position of one of the lowermost portions  28  which is hinged to brush material from the ends of seals at the ends of vanes  40 . The lowermost portion  28  is built far enough away from the interior  46  of the cylinder  12  to allow material which enters the cylinder  12  to fall below the distal ends  29  of the vanes so as not to be impinged between the advancing seal  50  and the interior  46  of the cylinder  12 . This prevents obstruction of the rotation of the multi-vane rotor  60  and fracture of the seals  50 . Also, this helps to prolong the life of the seals  50 .  
         [0030]    The hopper  16  of the present invention also includes a pivotally mounted surface  30  as shown in FIG. 1. The surface  30  allows the feeder  10  to compensate for the various types of material according to their densities. The exposure of the multi-vane rotor  24  to the material as it slides down the slope of the surface  30  is increased or decreased. The surface  30  pivots downward from a sidewall  32  of the hopper  16  and a distal end  34  of the surface  30  deflects material within the hopper  16  into the multi-vane rotor  24 . Preferably, the surface  30  is actuated by hand by the user from the exterior of the hopper  16 . The angle of the surface  30  relative to the sidewall from which it extends is selected based upon the type of material passing through the hopper  16 . For example, a firm and dense material requires little exposure to the vanes on rotor  24  as the material passes through the hopper  16  whereas a resilient, light material might require more exposure to the vanes on the rotor  24 . This change of exposure changes the depth of the sweep of the vanes on rotor  24  into the material. In order to change the amount of exposure of the vanes on rotor  24 , the surface  30  is raised or lowered, within the hopper  16 .  
         [0031]    As the surface is raised, the normal force of the material on the surface is also increased. Since the sliding friction of the material is directly proportional to the normal force, the material is slowed in its advance toward the vanes on rotor  24 . The amount of material being processed is reduced by the speed of its introduction as well as the decrease in the depth of the sweep of the vanes on rotor  24 . A reduction of the amount of material being swept allows the processing of heavy, dense material without obstruction of the vanes on rotor  24  and their consequent stoppage.  
         [0032]    As the surface  30  is lowered, the normal force of the material on the surface is decreased. The material is sped in its advance toward the vanes of the rotor  24 . The amount of material being processed is increased by the speed of its introduction as well as the increase in the depth of the sweep of the vanes on rotor  24 . An increase of the amount of material being swept allows for quicker processing of light, resilient materials, such as an insulation manufactured by Knauf, which does not obstruct the vanes on rotor  24 .  
         [0033]    Referring to FIG. 9, each end of the rotor  24  can be mounted in a diametric slot  101  in a circular disk  102  that is placed over a smaller concentric hole  105  in each end of the hopper  16 . The circular disks  102  are adjustably fixed to the hopper  16  with bolts  103  in arc-shaped slots  104  in the circular disks  102 . The disks  102  can be rotated so that the rotor  24  can be moved back and forth in the slots  101  so as to allow positioning of the rotor  24  anywhere within the circumference of the disk  102 . That is, the rotor  24  can be moved from one axis of rotation to another axis of rotation within the hopper  16 .  
         [0034]    Within the cylinder  12  is another multi-vaned rotor having a plurality of vanes  40 . The vanes  40  are spaced equidistant apart and a pair of adjacent vanes  40  define what is commonly referred to as a chamber  42 . The number of vanes  40  is such that there is always one vane between the outlet port  52  and the place for the high entrainment pressure to escape. In known machines, this is the inlet from the hopper  16  to the cylinder  12 . In the present invention, it is the leading edge of the first offset opening  70 , in FIGS. 2 and 3. The vanes  40  of the rotor extend radially outward such that the distal ends  44  of the vanes  40  are proximate to the cylindrical interior side wall  46  of the cylinder  12 .  
         [0035]    The distal ends  44  of the vanes  40  within the cylinder  12  typically include seals  50 . As the rotor rotates the vanes  40  within the cylinder  12 , the material fed into the cylinder  12  from the hopper  16  is captured by chamber  42 . As the chambers  42  revolve, each chamber  42  passes in turn over the outlet port  52  in the end wall  14  of the cylinder  12 . The seals  50  and their vanes of a chamber  42  pneumatically isolate it from the hopper as the chamber  42  passes over the outlet port  52 .  
         [0036]    [0036]FIG. 10 illustrates an alternative embodiment for the vanes of rotor  24 . Referring to FIG. 10, vanes  120  on rotor  24  can be displaced in and out on a radius related to the central axis of the rotor  24 . The volume swept can then be changed according to the proximity of the vanes  120  from the center of the rotor  24 . The vanes  120  can be adjustably mounted on radially extending tines  122  that extend from the center of the rotor  24  with fasteners such as u-bolts  130 . The further out the vane  120  are from the central axis of rotor  24 , the greater the volume of matter is swept.  
         [0037]    The outlet port  52  is configured to minimize the influence of the acceleration due to gravity on the introduction of material between mutually aligned inlet and outlet ports. The outlet port  52  is defined by an outermost lengthwise edge  54  defined by an increasing radius relative to an axis  60  and the innermost lengthwise edge  56  of the outlet port  52  has a constant radius relative to the axis  60 . Preferably, the outermost lengthwise edge  54  terminates tangent to the interior surface of the cylinder  12 . The outlet port  52  is further defined by a pair of widthwise edges  62 . Each of the widthwise edges  62  is substantially parallel to a vane  40  as each vane  40  passes each widthwise edge  62 . In other words, the widthwise edges  62  extend along a radial line from the axis  60 . Preferably, the inlet port is shaped to match the outlet port  52 .  
         [0038]    As explained in U.S. Pat. No. 4,710,067, hereby incorporated by reference, loose materials naturally exhibit an angle of repose. The angle of repose is the angle that the surface of a material takes with the horizontal once the material is formed into the pile by gravity flow.  
         [0039]    As the leading vane  40  of a chamber  12  passes the edge  62  of the outlet port  52 , the size of the outlet port  52  is small, with the outermost lengthwise edge  54  defined by the increasing-radius curve increasing from near the circle formed by the constant-radius curve. The amount of material that is first seen by the air-train and any that might fall into the air-train is small and can be moved by the air-train. As the vane revolves further, increasing amounts of material are exposed because of the shape of the outermost lengthwise edge  54  and are removed incrementally. At some point before tangency with the interior surface of the cylinder  12 , the outermost lengthwise edge  54  defined by the increasing-radius curve will substantially equal the natural angle of repose of the material being processed, which will vary from one material to another. At that point, no further material will fall into place before the air-train and material will be introduced only by the speed of revolution of the vane.  
         [0040]    [0040]FIG. 6 illustrates positions of a particular vane  40 ′ as it moves along from points A-F. At point B, a small volume of material will be exposed to the air-train and will fall into it. At some point, C in the case of the material shown here, a line tangent to the outermost lengthwise edge  54  is less than the angle of natural repose of the material. From this point forward, the speed of the introduction of the material is determined by only the speed of revolution of the vane  40 ′. FIG. 7 graphically illustrates that, as the vane  40 ′ revolves, even portions of material are removed from the surface of the pile of material along the outermost lengthwise edge  54  until the chamber  42  is completely emptied as the vane  40 ′ reaches the end of the length of the outermost lengthwise edge  54  at point F. The outlet port  52  empties into a conduit  43  shown in FIG. 8, that changes from the shape of the outlet port  52  to a cylinder shaped connection to be attached to a hose-pipe  45 .  
         [0041]    The feeder  10  of the present invention also includes a pair of offset openings  70  as best shown in FIGS. 2 and 3. The offset openings  70  extend as slots from one end of the cylinder  12  to the other along each side of the opening from the hopper  16  to the cylinder  12 . Preferably, as best shown in FIGS. 4 and 5, the length of each offset opening  70  corresponds with the length of the cylinder  12 . However, only one of the offset openings  70 , in the form of a slot, should be substantially the same length as the cylinder  12 , preferably the second one in the direction of rotation. The offset openings  70  communicate with the interior of the cylinder  12 . Note that both the offset openings  70  are in communication with the hopper  16  as the vanes  40  revolve. The width of the offset openings  70  is sufficiently great to straddle each vane  40  as it revolves to intermittently allow concurrent communication with two adjacent chambers  42  as the feeder  10  rotates. In other words, each offset opening  70  is sized widthwise to straddle the width of each vane  40  as each vane  40  passes underneath. This contrasts with the size of the vent hole in my &#39;067 patent.  
         [0042]    After a chamber  42  has passed the outlet port, it has a pressure equal to the entrainment pressure. When the seals revolve to the first offset opening  70 , the rest of the air pressure is discharged mainly through the offset openings  70  rather than through the hopper  16 . The paths taken by the material from the hopper  16  and into the cylinder  12  are explained in greater detail below.  
         [0043]    As shown in FIG. 2, the offset openings  70 , commonly referred to as defining a chamber, may have a hinged opening cover  72  at each of their tops. This hinged opening cover  72  equalizes the pressure surges built up as a chamber  42  discharges pressure from the cylinder  12  of feeder  10  as the chamber  42  passes beneath the first offset opening  70 . The hinged opening cover  72  and the offset opening  70  are sized to allow periodic maintenance of the seals and the interior of the feeder  10 .  
         [0044]    Alternatively, as shown in FIG. 3, the tops of the offset openings  70  may instead include a conduit, such as a rubber hose  74 , which is vented from the offset openings  70 , to the exterior of the cylinder  12 , and back into the hopper  16 . Any number of hoses may be utilized. However, the number and size of the hoses  74  is dependent upon the type and volume of material intended to be used. Typically, the size of each of the hoses  74  is considerably larger that the hoses utilized in my &#39;067 patent. Preferably, the rubber hoses  74  have about a 2 inch diameter. The discharging air might bear dust or lint that will pass from the offset openings  70  and past opening covers  72  or though the hoses  74  into the hopper  16 .  
         [0045]    In operation, the feeder  10  provides a pathway  80   a - b  which passes over the outlet port  52 . In FIGS. 2 and 3, the pathway  80   a - b  is best illustrated by referring to FIGS. 2 and 3. In FIGS. 2 and 3, the portion of the pathway  80   a - b  where material is placed in the hopper  16  is identified by the solid line referenced as  80   a . The pathway  80   a - b  continues from the hopper and into the cylinder  12  in a clockwise manner. The direction of the rotor is a matter of choice, but the shape of the outlet port  52 , as described above, is dependent on the direction of the motor. The material following along the portion of the pathway  80   a - b  from the bottom of the hopper  16  down to the outlet port  52 , and which is discharged through outlet port  52 , is not identified by a reference number.  
         [0046]    Still referring to FIGS. 2 and 3, the portion of the pathway  80   a - b  where there is high pressure air in each chamber  42  is shown by a broken line having reference number  80   b . A portion of the pathway portion  80   b  in each embodiment leads into the offset opening  70  on the left while the remainder branches off and leads under the hopper and into the offset opening  70  on the right. In FIG. 2, the pathway portion  80   b  terminates as the high pressure air reaches the exterior of the feeder  10  and out the hinged opening cover  72 . In FIG. 3 the high pressure air continues through hoses  74  and back into the hopper  16 .  
         [0047]    The present invention has been described in relation to particular embodiments which are intended in all respects to be illustrative rather than restrictive. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is described by the appended claims and supported by the foregoing description.