Abstract:
Method and apparatus are described for a guard for a rotating member. The guard comprises a shell surrounding the rotating member, and a plenum member concentrically spaced from an interior surface of the shell, the shell comprising an inlet for receiving air and an outlet for discharging the air so that rotation of the rotating member draws air through the inlet and into the plenum member and the air circulates through the plenum member to cool the shell before it exhausts through the outlet.

Description:
This invention relates to a directed air flow coupling guard. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a coupling guard of the present embodiment. 
     FIG. 2 is a cross sectional view of the coupling guard of FIG. 1 taken along the line  2 — 2  of FIG.  1 . 
     FIG. 3 is an exploded view of the coupling guard of FIG. 1 with the coupling removed. 
     FIG. 4 is a longitudinal sectional view of the coupling guard of FIG. 1 taken along the line  4 — 4  of FIG.  1 . 
     FIG. 5 is an exploded view of a coupling guard of an alternative embodiment. 
     FIG. 6 is a plan view of a pair of baffle plates according to the alternative embodiment of FIG.  5 . 
     FIG. 7 is a longitudinal sectional view of a coupling guard of an alternative embodiment. 
     FIGS. 8 a-d  are perspective views of baffle plates, showing the front and back surfaces, according to the alternative embodiment of FIG.  7 . 
    
    
     DETAILED DESCRIPTION 
     Referring to FIG. 1, the reference numeral  10  refers to a coupling guard assembly that encloses a rotating coupling  12 . It is understood that although a coupling is shown as an example, the guard could surround a shaft, a hub, or any rotating member. The guard assembly  10  has a pair of semi-cylindrical shell portions  14  and  16 . The upper shell portion  14  has an opening  18 , for reasons to be described, and an intake port  20  for allowing air flow into the guard  10 . 
     As better shown in FIG. 2, a pair of J-shaped channels  22  and  24  are formed along the longitudinal edges of the upper shell portion  14 . Correspondingly, the lower shell portion  16  has a pair of bent flanges  26  and  28  running lengthwise along the edges of the lower portion. The bent flanges  26  and  28  are received in the J-shaped channels  22  and  24  of the upper shell portion when the channels are flexed outwardly. As the J-shaped channels  22  and  24  return to the unflexed position, the bent flanges  26  and  28  are retained, and thus the channels and the flanges cooperate to form a snap-together connection. Thus connected, the upper and lower shell portions  14  and  16  define a substantially cylindrical enclosure, or shell, around the coupling  12 . It is understood that gaskets (not depicted) may be used to seal adjoining portions of the shells  14  and  16 . 
     Returning to FIG. 1, the upper and lower shell portions  14  and  16  overlap a plenum member  30  (FIG.  3 ). The plenum member  30  has a substantially cylindrical outer portion, and it is understood that gaskets may be used to seal the portion of the plenum member overlapped by the shells  14  and  16 . An adapter  32  is disposed adjacent to the plenum member  30 , and a vent pipe  34  extends from the plenum member  30  and protrudes outwardly through the opening  18  of the upper shell portion  14  to allow air flow from the interior of the guard  10  to the environment, as will be described. 
     Referring to FIGS. 2 and 3, the plenum member  30  has a ring  36 , and the vent pipe  34  is attached to the ring. An orthogonal annular wall  38  extends from an inner surface of the ring  36  to partially define a plenum space around the coupling  12 , as will be described. As shown in FIG. 3, the orthogonal annular wall  38  has an opening  38   a  for accommodating the coupling, which has been removed in FIG. 3 for simplicity of illustration. 
     As shown in FIG. 2, an opening  40  in the ring  36  allows the plenum space to be in communication with the vent pipe  34 . A scraper plate  42  is disposed adjacent to the opening  40  for directing air currents, represented by arrows A, from the plenum space to the vent pipe  34 . 
     A plurality of bolts  44  extend from the adapter  32 , axially relative to the shell portions  14  and  16 , for attaching the adapter to the ring  36  of the plenum member  30 . The bolts  44  are received by a corresponding plurality of tubular receivers  46 , disposed along the exterior surface of the ring  36 , and held in place by any conventional means. The tubular receivers  46  cooperate with the exterior surface of the ring  36 , and the shell portions  14  and  16 , to define axial air passages  47  (FIG. 2) around the ring. 
     A pair of annular baffle plates  48  and  50  are captured between the adapter  32  and the ring  36 , and are disposed transversely to the axis of the shell portions  14  and  16 . The plate  48  has a large opening  52  to accommodate the coupling  12 , as well as a plurality of angularly spaced openings  54 , each of which is disposed adjacent a triangular baffle  56 . A plurality of channels  57  are defined between the baffles  56 . 
     The plate  50  cooperates with the ring  36  and the wall  38  to define the plenum space, and has a large opening  58  to accommodate the coupling  12 , and a plurality of angularly spaced openings  60 . Each opening  60  is disposed through a triangular baffle  62  and a plurality of channels  63  are defined between the baffles  62 . 
     The coupling  12  is sealed by an annular labyrinth seal  64 , a portion of which is illustrated in FIG.  4 . The outer periphery of the seal  64  is attached to the inner surface of the adapter  32  in any known manner and the surface of the seal defining its central opening receives the coupling  12  and sealingly engages the outer surface of the coupling. 
     In operation, the coupling  12  is rotated by a power source (not shown), the rotation producing undesirable heat. Referring to FIGS. 2 and 4, protrusions of the rotating coupling  12 , such as bolts, connectors, and other non-smooth features, act as impellers, creating the aforementioned air currents A (FIG.  2 ), which circulate equatorially inside the plenum space relative to the coupling. As better shown in FIG. 2, a portion of the air currents A, denoted A 1 , are directed by the scraper plate  42  out the opening  40 , and through the vent pipe  34 , thus venting heat from the plenum space to cool the shell. 
     The rotating coupling  12  creates areas of relatively high pressure, denoted HP, at the radial extremities of the coupling. Areas of relatively low pressure, denoted LP, are created closer to the axis of the coupling  12 . Fresh air, in the form of air currents, represented by arrows B (FIG.  4 ), is drawn into the guard  10  through the intake port  20  by the relatively low pressure LP surrounding the coupling  12 . 
     A portion of the air currents B (FIG.  4 ), represented by arrows B 1  (FIG.  4 ), are drawn by low pressure through the air passages  47  defined between the ring  36 , the tubular receivers  46 , and either the upper or lower shell portions,  14  and  16 , respectively. As shown in FIG. 4, the air currents B 1  are drawn into the channels  63  (FIG. 3) of the plate  50  by low pressure surrounding the coupling  12 . The channels  63  allow the air currents B 1  to be directed toward the coupling, the air currents B 1  then are drawn into the plenum space to be exhausted. Thus, the constant unidirectional flow of air currents B 1  removes heat that would otherwise be building up in the space between the ring  36  and the upper and lower shell portions,  14  and  16 , thus lessening heat transferred to the upper and lower shell portions. 
     Referring back to the fresh air currents B (FIG.  4 ), another portion of the fresh air currents B, represented by arrows B 2 , is drawn by low pressure through the opening  38   a  of the wall  38  into the plenum space defined by the wall  38 , the ring  36 , and plate  50 . These air currents B 2  replenish the air in the plenum space, a portion of which, as noted above, is exhausted as the air currents A 1  (FIG. 2) through the vent pipe  34  (shown in phantom in FIG. 4 for convenience of reference). 
     As the equatorial air currents A (FIG.  2 ), replenished by air currents B 1  and B 2 , pass by the coupling  12 , they receive heat, which is exhausted with the air currents A 1  (FIG.  2 ), thus lessening heat transferred to the upper and lower shell portions,  14  and  16 . The exhaust of the air currents A 1  is assisted by the relatively high pressure HP experienced along the interior surface of the ring  36 . 
     Moreover, the relatively high pressure HP experienced along the interior surface of the ring  36  also forces some air currents, represented by arrows C, out of the plenum space through the angularly spaced openings  60  of the plate  50  and the angularly spaced openings  54  of the plate  48 . The air currents C enter a space between the plate  48  and the labyrinth seal  64  to decrease the low pressure area LP around (“buffer”) the coupling  12 , which greatly increases the efficiency of the labyrinth seal. Increasing the efficiency of the labyrinth seal  64  reduces the chance of smoke-producing oil entering the guard  10 . 
     It is understood that a second plenum system, substantially identical to that described above, may be disposed around the coupling on the other side of the intake port  20  (to the left in FIG.  4 ). 
     Referring to FIGS. 5 and 6, the reference numeral  70  refers to an alternative embodiment of a coupling guard assembly for enclosing a rotating coupling (not depicted). The guard assembly  70  comprises a pair of semicylindrical shell portions  74  and  76 . The upper shell portion  74  has a cutaway  78 , and an intake port  80  for intake of air. 
     A pair of J-shaped channels  82  and  84  are formed along the longitudinal edges of the upper shell portion  74 . Correspondingly, the lower shell portion  76  has a pair of bent flanges  86  and  88  running lengthwise along the edges of the lower portion. The bent flanges  86  and  88  are received in the J-shaped channels  82  and  84  of the upper shell portion when the channels are flexed relatively outward. As the J-shaped channels  82  and  84  return to an unflexed position, the bent flanges  86  and  88  are retained, and thus the channels and the flanges cooperate to form a snap-together connection. Thus connected, the upper and lower shell portions  74  and  76  define a substantially cylindrical shell around the coupling. It is understood that gaskets (not depicted) may be used to seal adjoining portions of the shells  74  and  76 . The lower shell portion  76  also has an oil drain pipe  90 , for removal of any fluid accumulating in the guard  70 . 
     The upper and lower shell portions  74  and  76  are connected to a plenum member  92 . The plenum member  92  comprises a vent pipe  94  which is accommodated by the cutaway  78  of the shell portion  74 . The vent pipe  94  protrudes radially outwardly from a ring  96 . A second ring  98  is disposed radially inwardly and concentric to the ring  96 . The rings  96  and  98  are connected, and spaced apart, by a plurality of tubular receivers  100  to form air passages  101 . 
     The interior surface of the ring  98  and an orthogonal wall  102  cooperate to define a plenum space around the coupling, the wall having an opening  102   a.  An opening (not depicted) in the rings  98  and  96  allows the plenum space to be in fluid communication with the vent pipe  94 . Means for directing air currents from the plenum space to the vent pipe  94 , for example, such as the scraper plate  42  (FIG. 2) of the previous embodiment, are disposed adjacent to the opening. 
     An adapter  104  is disposed adjacent to the rings  96  and  98 , and houses a conventional labyrinth seal  105 , a portion of which is illustrated in FIG. 5. A plurality of bolts  106  extend axially, relative to the shell portions  74  and  76 , from the adapter  104 . The bolts  106  are received by the tubular receivers  100  disposed along the exterior surface of the ring  96 , and are secured by any conventional means, thus attaching the adapter  104  to the plenum member  92 . 
     A pair of annular baffle plates  108  and  110  are disposed transverse to the axis of the shell portions  74  and  76 , and are retained between the adapter  104  and the plenum member  92 . As better shown in FIG. 6, the plate  108  has a large opening  112  to accommodate the coupling, and a plurality of angularly spaced openings  114 , for reasons to be described. The plate  108  also has a plurality of reinforced openings  116 , the openings each having a reinforcing member  118  for providing additional thickness to the plate  108 . 
     The plate  110  has a large opening  120  to accommodate the coupling, and a plurality of angularly spaced openings  122 , for reasons to be described. Each opening  122  is disposed on a triangular baffle  124 . Adjacent baffles  124  cooperate with the plate  110  to define a channel  126 . A set of pins  128  are disposed on the plate  110  in positions corresponding to the positions of the reinforced openings  116  of the plate  108 . During assembly of the guard, the pins  128  are inserted into the reinforced openings  116 , thus aligning the angularly spaced openings  114  of plate  108  with the angularly spaced openings  122  of plate  110 , creating a plurality of air passages through the plates  108  and  110 . 
     In operation, the assembled embodiment of FIGS. 5 and 6 operates substantially similar to the previously described embodiment of FIGS. 1-4. Protrusions of the rotating coupling (not depicted) act as impellers, creating areas of relatively high pressure at the radial extremities of the coupling, and areas of relatively low pressure closer to the axis of the coupling. The rotating coupling further produces air currents which circulate equatorially inside the plenum space defined by the plate  110 , the ring  98 , and the wall  102 . As the air currents pass by the coupling they receive heat, and a portion of these air currents are exhausted through the vent pipe  94 , thereby reducing the amount of heat that would otherwise be built up and transferred to the shell (portions  74  and  76 ). The relatively high pressure experienced at the radial extremities of the coupling encourages this exhausting of the air currents through the vent pipe  94 . 
     Fresh air is drawn into the guard  70  through the intake port  80  by the low pressure surrounding the coupling. A portion of the fresh air is drawn axially by low pressure through the air passages  101 , decreasing heat transfer from the ring  98  to the ring  96 . These air currents are then drawn into the plenum space to replenish the air currents exhausted through the vent pipe  94 . Another portion of the fresh air is drawn by low pressure around the coupling through the opening  102   a  of the wall  102  into the plenum space to replenish the air currents exhausted through the vent pipe  94 . The relatively high pressure HP experienced along the radial extremities of the coupling forces some air currents out of the plenum space through the angularly spaced openings  122  and  114  of the plates to buffer the labyrinth seal  105 . It is understood that exhausted air may be directed to the drain  90  for the purpose of blowing out the drain. 
     Referring to FIG. 7, the reference numeral  130  refers to yet another embodiment of a coupling guard assembly for enclosing a rotating coupling  132 . It is understood that although a coupling is shown as an example, the guard could surround a shaft, a hub, or any rotating member. The guard assembly  130  has a substantially cylindrical shell  134  surrounding the coupling  132 , and having an opening (not depicted) for allowing air flow into the guard  130 . The shell  134  receives an inner ring  136 , spaced from the shell to define an axial air passage  138  around the ring. 
     An orthogonal annular wall  140  extends from an inner surface of the ring  136  to partially define a plenum space around the coupling  132 , as will be described. The orthogonal annular wall  140  has an opening  140   a  for accommodating the coupling  132 . 
     A vent pipe  142  extends from the ring  136  and protrudes outwardly through the shell  134  to allow air flow from the plenum space to the environment, as will be described. An opening  144  in the ring  136  allows the plenum space to be in communication with the vent pipe  142 . A scraper plate  146  is disposed adjacent to the opening  144  for directing air currents from the plenum space to the vent pipe  142 , as will be described. 
     Four annular baffle plates,  148 - 154  are disposed adjacent to the ring  136 , transversely to the axis of the shell  134 . The plate  148  further defines the plenum space around the coupling  132 , while plates  150 - 154  cooperate for directing air to the coupling and sealingly engaging the outer surface of the coupling. 
     Referring now to FIG. 8 a,  the plate  148  is has a first side  148   a  (illustrated to the right) which helps define the plenum space (FIG.  7 ), and a second side  148   b  (illustrated to the left). The plate  148  has a large opening  156  to accommodate the coupling  132 , and a plurality of angularly spaced openings  158 . The side  148   b  of the plate has projections  160 , surrounding the angularly spaced openings  158 , each projection comprising a lip portion  160   a,  and a base portion  160   b.  A plurality of channels  162  are defined between the projections  160 . 
     Referring now to FIG. 8 b,  the plate  150  has a first side  150   a  (illustrated to the left) which is disposed adjacent to side  148   b  (FIG. 8 a ) of plate  148  in FIG. 7. A groove  164  of side  150   a  receives the lip  160   a  (FIG. 8 a ) of plate  148 . The plate  150  has a second side  150   b  (illustrated to the right), which has a projection  165  surrounding the radial extremity of the plate, each projection comprising a lip portion  165   a,  and a base portion  165   b.  The plate  150  has a large tapered opening  166  to accommodate the coupling  132 , and a plurality of angularly spaced openings  168 , which cooperate to define an air passage with the angularly spaced openings  158  of the plate  148 . A plurality of bolt holes  170  are disposed in the plate  150 . 
     Referring now to FIG. 8 c,  the plate  152  has a first side  152   a  (illustrated to the left) which is disposed adjacent to side  150   b  (FIG. 8 b ) of plate  150  in FIG. 7. A groove  172  of side  152   a  receives the lip  165   a  (FIG. 8 b ) of plate  150 . The plate  152  has a second side  152   b  (illustrated to the right), which has a large groove  174 . The plate  150  has a large tapered opening  176  to accommodate the coupling  132 . A plurality of bolt holes  178  are disposed in the plate  152  for aligning with the bolt holes  170  (FIG. 8 b ) of the plate  150 . 
     Referring now to FIG. 8 d,  the plate  154  has a first side  154   a  (illustrated to the right) which is disposed adjacent to side  152   b  (FIG. 8 c ) of plate  152  in FIG. 7. A plurality of projections  180  of side  152   a  engage the large groove  174  (FIG. 8 c ) of plate  152  in FIG.  7 . The plate  154  has a rim  182  surrounding the radial extremity of the plate. The plate  154   b  has a second side  154   b  (illustrated to the left), which has a notch  184  for trapping oil, as well as a groove  185  disposed around the radial extremity of the plate. The plate  154  has a large tapered opening  186  to accommodate the coupling  132 , and a plurality of drain holes  188  for allowing lubricating oil to escape from between the plates  152  and  154 . 
     In operation, and referring to FIGS. 7 and 8 a-d,  the coupling  132  is rotated by a power source (not shown), the rotation producing undesirable heat. Protrusions of the rotating coupling  132 , such as bolts, connectors, and other non-smooth features, act as impellers, creating air currents, represented by arrows E, which circulate equatorially inside the plenum space relative to the coupling. A portion of the air currents E, denoted E 1 , are directed by the scraper plate  146  out the opening  144 , and through the vent pipe  142 , thus venting heat from the plenum space to cool the shell. 
     The rotating coupling  132  creates areas of relatively high pressure, denoted HP, at the radial extremities of the coupling. Areas of relatively low pressure, denoted LP, are created closer to the axis of the coupling  132 . Fresh air, represented by arrows F, is drawn by the relatively low pressure LP surrounding the coupling  132  into the guard  130  through an opening (not depicted). A portion of the air currents F, represented by arrows F 1 , are drawn by low pressure through the air passages  138  defined between the ring  136  and the shell  134 . As shown in FIG. 7, the air currents F 1  are then drawn into the channels  162  (FIG. 8 a ) of the plate  148  by the low pressure surrounding the coupling  132 . The channels  162  allow the air currents F 1  to pass between the plates  148  and  150 , and be directed toward the coupling, thereafter returning to the plenum space to be exhausted. Thus, the constant unidirectional flow of air currents F 1  removes heat that would otherwise be building up in the space between the ring  136  and the shell  134 , thus lessening heat transferred to the shell. 
     Referring back to the fresh air currents F, another portion of the fresh air currents F, represented by arrows F 2 , is drawn by low pressure through the opening  140   a  of the wall  140  into the plenum space defined by the wall  140 , the ring  136 , and plate  148 . These air currents F 2  replenish the air in the plenum space, a portion of which, as noted above, is exhausted as the air currents E 1  through the vent pipe  142 . As the equatorial air currents E, replenished by air currents F 1  and F 2 , pass by the coupling  132 , they receive heat, which is exhausted with the air currents E 1 , thus lessening heat transferred to the shell  134 . The exhaust of the air currents E 1  is assisted by the relatively high pressure HP experienced along the interior surface of the ring  136 . 
     Moreover, the relatively high pressure HP experienced along the interior surface of the ring  136  also forces some air currents, represented by arrows G, out of the plenum space through the angularly spaced openings  158  of the plate  148  and the angularly spaced openings  168  of the plate  150 . The air currents G enter a space between the plate  150  and the plate  152  to decrease the low pressure area LP around the coupling  132 , which greatly increases the efficiency of the seal formed by the plates  152  and  154 . Increasing the efficiency of the aforementioned seal reduces the chance of smoke-producing oil entering the guard  130 . 
     Another set of air currents, represented by arrows H, may be introduced between the plates  154  and  152  to further increase the efficiency of the aforementioned seal. It is understood that the air currents H may be used to blow out lubricating oil that may collect between the plates  152  and  154  through the drain holes  188  (FIG. 8 d ) of the plate  154 . 
     It is understood that a second plenum system, substantially identical to that described above, may be disposed around the coupling. 
     Furthermore, it is understood that all spatial references, such as inner, outer, left, and right, are only for the purposes of explanation of the drawings. This disclosure shows and describes illustrative embodiments, however, the disclosure contemplates a wide range of modifications, changes, and substitutions. Such variations may employ only some features of the embodiments without departing from the scope of the underlying invention. Accordingly, any appropriate construction of the appended claims will reflect the broad scope of the underlying invention.