Abstract:
An internal staged suppression system for suppressing a hazard occurring in a grain dryer includes a plurality of vertical column sections and at least one spray head positioned radially inward within the interior of the grain dryer. The spray head includes a deflector cap that generates a substantially horizontal spray of water sufficient to reach the walls defining the grain columns.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/764,662, filed Feb. 14, 2013, the disclosure of which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention relates generally to grain dryers. More specifically, the invention is directed to an internal staged suppression system for suppressing a hazard occurring in a grain dryer. 
       BACKGROUND OF THE INVENTION 
       [0003]    Hazards that may occur in a grain dryer, such as a dust explosion, fire, or other such events, are difficult to suppress because the grain and the attendant hazard are contained within the dryer. Some of these hazards may be fought by spraying water on the exterior of the grain dryer. This, however, does little to suppress the hazard at its source, i.e., within the dryer. Thus, these hazards can frequently escalate in severity, ultimately resulting in the destruction of the dryer. It can also expose operators and firefighters to unpredictable safety hazards. The invention provides an efficient and economical internal staged suppression system for suppressing a hazardous event in a grain dryer. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    The invention is an internal staged suppression system for suppressing a hazardous event occurring in a grain dryer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a front elevational view of a grain dryer in which the internal staged suppression system according to the invention is positioned; 
           [0006]      FIG. 2  is a cross-sectional view taken along line A-A of  FIG. 1  showing the internal staged suppression system according to invention positioned in the grain dryer; 
           [0007]      FIG. 3  is a detailed view of the inlet positioned on a dryer foundation according to the invention; 
           [0008]      FIG. 4  is a side elevational view of the inlet according to the invention; 
           [0009]      FIG. 5  is a detailed view of two vertical column sections and a groove coupler according to the invention; 
           [0010]      FIG. 6  is a is a detailed view of a vertical column section, a bend, three horizontal column sections, three dispersion heads, and groove couplers according to the invention; 
           [0011]      FIG. 7  is a is a detailed view of a vertical column section, a bend, a horizontal column section, a dispersion head, and groove couplers according to the invention; 
           [0012]      FIG. 8  is a detailed view of two horizontal column sections, a dispersion head, and groove couplers according to the invention; 
           [0013]      FIG. 9  is a detailed view of a horizontal column section, a dispersion head and a groove coupler according to the invention; 
           [0014]      FIG. 10  is a perspective view of a dispersion head according to the invention; 
           [0015]      FIG. 11  is a perspective view of a groove coupler according to the invention; 
           [0016]      FIG. 12  is a perspective view of a 90° bend according to the invention; 
           [0017]      FIG. 13  is a perspective view of a vertical column section having a length L 1  according to the invention; 
           [0018]      FIG. 14  is a perspective view of a horizontal inlet section according to the invention; 
           [0019]      FIG. 15  is a perspective view of a vertical column section having a length L 2  according to the invention; 
           [0020]      FIG. 16  is a perspective view of a horizontal column section according to the invention. 
           [0021]      FIG. 17  is an alternative embodiment of a front elevational view of a grain dryer in which the internal staged suppression system according to the invention is positioned; 
           [0022]      FIG. 18  is an enlarged portion of the grain dryer of  FIG. 17  showing a detailed view of an inlet positioned on a dryer foundation according to the invention; 
           [0023]      FIG. 19  is perspective view of another embodiment of a suppression system in a grain dryer (shown in phantom) and further depicting a suppression medium distribution pattern; 
           [0024]      FIG. 20  is an elevational view of a spray head for use in a hazard suppression system in accordance with the invention; and 
           [0025]      FIG. 21  is a plan view of the spray head of  FIG. 20 . 
           [0026]      FIG. 22  is a perspective view of an embodiment of a riser stand; 
           [0027]      FIG. 23  is an exploded perspective view of an embodiment of a squeeze nut, as part of a riser support assembly; 
           [0028]      FIG. 24  is a perspective view of an embodiment of an offset supply tube; 
           [0029]      FIG. 25  is an elevational view, in partial cross section, of a drainable connecting elbow. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    The invention will now be described in detail with reference being made to the drawings. The internal staged suppression system according to the invention is indicated generally in the drawing by the reference number “ 10 .” Referring to  FIGS. 1 and 2 , the internal staged suppression system  10  is utilized with a grain dryer  12  having an exterior  14 , an interior  16 , a bottom  18  and a top  20 . The grain dryer  12  is positioned on a foundation  22  at the bottom  18 . The interior  16  includes a grain column  24  for containing grain during drying and a heating section such as a heat plenum chamber  26  adjacent to the column  24 . The grain column  24  is defined, in part, by the exterior  14  and the interior  16 , which may be configured as perforated surfaces that permit heated air flow in order to dry the grain contained therein. The grain column  24  may be configured as a plurality of grain columns that are separated by walls extending between the exterior  14  and interior  16  of the grain dryer  12  and distributed around the perimeter thereof. The chamber  26  has a heating device such as a burner  28 . 
         [0031]      FIGS. 1-16  show an embodiment of the internal staged suppression system  10  according to the invention. As shown in  FIGS. 1-5 , the system  10  includes an inlet  30  positioned on or near the foundation  22 . One or more vertical column sections  32 , that are in fluid communication with the inlet  30  by a horizontal inlet section  34 , extending from the bottom  18  to the top  20  through the interior  16  of the grain dryer  12 . Though shown and illustrated in conjunction with the vertically oriented grain dryer  12 , the various embodiments of the internal staged suppression system described herein are equally applicable to a horizontal grain dryer, which are known in the art. 
         [0032]    Referring to  FIGS. 6-16 , the system  10  includes one or more horizontal column sections  36  that are in fluid communication with the vertical column sections  32 . The horizontal column sections  36  are in fluid communication with one or more bends  38 . In an embodiment, the bends  38  are system specific. For example, the bends  38  can have configurations of about 90° ( FIG. 12 ), along with other angular offsets, such as 18°, 22.5°, 30°, 45°, and any other suitable angles. As shown in  FIGS. 6-10 , the horizontal column sections  36  are arranged in a generally linear configuration and positioned at or near the top  20  of the grain dryer  12 . The horizontal column sections  36  are in fluid communication with one or more outlets such as one or more high volume dispersion heads  40 . In an embodiment, each head  40  has a head inlet  42  with a cap  44  to control the delivery of water in a generally horizontal pattern. In an embodiment, the cap  44  is capable of being lifted by pressurized water to a system specific clearance and then closed by gravity to seal the head  40 . Each of the heads  40  is positioned on a head section  46 . In the illustrated embodiment, the sections  32 ,  34 ,  36  and  46  are flanged. However, in another embodiment described below, the sections  32 ,  34 ,  36 , and  46  may be assembled by way of conventional pipe threaded connections, including couplings, unions, elbows, tees, and any other suitable joints which are well known in the art of piping and plumbing. Thus, any reference made to grooved connections between components may also encompass or include threaded connections. As shown in  FIGS. 5-9 , the sections  32 ,  34 ,  36  and  46  and the bends  38  are coupled by one or more groove couplers  48  ( FIG. 11 ). 
         [0033]    In an embodiment, the vertical column sections  32 , the horizontal inlet section  34 , the horizontal column sections  36 , the head sections  46  and the bends  38  are sized and adapted to carry a predetermined volume of pressurized suppression media, such as water, through the system  10 . In an embodiment, the system  10  delivers a high volume of water in a generally horizontal pattern at substantial pressure to penetrate the grain column  24  as well as to saturate debris in the heat plenum chamber  26 . In an embodiment, the system  10  locates one or more heads  40  in the center of the grain dryer  12  for substantially 360° delivery of water on a horizontal plane. In an embodiment, the system  10  delivers water to the grain dryer  12  at multiple levels. 
         [0034]    The use of the internal staged suppression system  10  will now be described. Referring to  FIGS. 1-9  pressurized water is delivered to the inlet  30  by a hose or other conduit (not shown) in response to a hazardous event occurring in the grain dryer  12 . The water travels though the vertical column sections  32  to the horizontal column sections  36  and is discharged through the one or more heads  40  to suppress the fire. As it will be appreciated, the system  10  provides high-volume placement of water on demand to suppress a hazard event in a grain dryer  12  in an efficient and economical manner. 
         [0035]    Referring now to  FIGS. 17-19 , there is illustrated another embodiment of an internal staged suppression system, shown generally at  100 . The internal staged suppression system  100  may include portions that are similar to the internal staged suppression system  10  described above. The internal staged suppression system  100  is located within a grain dryer  112 . The grain dryer  112  includes a top section  112   a,  a burner section  112   b,  and a cooling section  112   c.  Grain is admitted into the dryer  112  through a loading port  114  located at an outer top covering  116  of the dryer  112 , as shown in  FIG. 19 . The grain flow, as indicated by the solid lines, over a top section  118  of a heated interior  120 . The heated interior  120  includes a heat source, configured as a burner assembly  122 , which is conventional in the art. The grain dryer  112  is supported by one or more support stanchions  124 , typically located around the base. The stanchions  124  are typically situated under walls  126  that define individual grain columns  128 , as shown in  FIG. 18 . The grain columns  128  are further defined by an exterior wall  130  and an interior wall  132 , as shown in  FIG. 19 . The interior and exterior walls  130  and  132  may be perforated to permit heated air to flow through the grain stored in the grain columns  124 . 
         [0036]    As is also shown in  FIG. 18 , an inlet section assembly, shown generally at  134 , extends upwardly through a riser  136  and enters the grain dryer  112  through the exterior wall  132 . The inlet section assembly  134  includes a one or more vertical column sections  32  that extend up through the riser  136 . The vertical sections  32  are connected together by groove couplers  48 , as shown in  FIG. 5 . A lower end of the inlet section assembly  134  extends below the riser  136  and terminates in a drainable connecting elbow  138 , as shown in  FIG. 25 . The drainable connecting elbow  138  includes a drainage port  140  configured to accept a conventional valve (not shown) in order to evacuate water from the internal staged suppression system  100 . The drainable connecting elbow  138  includes grooved ends  140  configured to mount by couplers  48  to the vertical sections  32  and horizontal inlet section  34 . The horizontal inlet section  34  extends outwardly and terminates in the inlet  30 . In one embodiment, the inlet  30  is configured to accept a Fire Department Connection (FDC) type connector such as, for example, a two simultaneous hose, or siamese, connection. 
         [0037]    Referring to  FIGS. 22 and 23 , the riser  136  is illustrated in detail. The riser  136  includes a column aperture  142  that permits the vertical section to pass therethrough. The riser  136  further includes mounting apertures  144  that are configured to fix a squeeze nut  146  to the riser. The squeeze nut  146  is formed in two generally similar halves. Each half includes arcuate cutouts  148 , that are generally semi-circular cutouts, and clamping apertures  150  configured to fix the two halves of the squeeze nut  146  together. The clamping apertures  150  (and fasteners—not shown) permit the cutouts  148  of the squeeze nut  146  to clamp onto the pipe section such that the vertical column section  32  is fixed relative to the squeeze nut  146 . The assembled squeeze nut  146  rests on top of the riser  136  and is attached by fasteners (not shown) extending through mounting holes  152  to the corresponding mounting apertures  144  on the riser  136 . This attachment configuration permits length compensation of vertical column sections  32  relative to the foundation of the grain dryer  112 . Since the suppression system  100  may be mounted when the grain dryer is empty, relaxing the clamp fit of the squeeze nut  146  when the dryer is filled with grain after system installation permits compensation of the deflections associated with the weight of grain bearing against and supported by the dryer. Thus, residual stresses that would otherwise be applied to the system can now be relaxed and reduced. In one embodiment, an offset column section  154 , shown in  FIG. 24 , may extend through the riser  136  in order to clear obstacles, such as burner fuel feeds, grain discharge chute hatches or grain flow regulators, and the like. 
         [0038]    Referring again to  FIG. 19 , the internal staged suppression system  100  is shown in a water discharge mode within the grain dryer  112 , shown in phantom. In the embodiment shown in  FIG. 19 , water is delivered by vertical column sections  156 , similar to vertical column sections  32  except having threaded end connections. In certain embodiments, the threaded connections inside the grain dryer  112  may provide a leak resistant connection during exposure to the heat output of the burner assembly  122 . In the illustrated embodiment of  FIG. 19 , a single spray head  158  is located in the approximate radial center of two sections, the top section  112   a  and the burner section  112   b,  of the dryer  112 . Alternatively, the spray heads may be located in any number and in any section or height position within the dryer  112 . The spray head  158  is shown, in detail, in  FIGS. 20 and 21 . 
         [0039]    The spray head  158  includes a sprayer base  160  and a deflector cap  162 . The deflector cap  162  is mounted to the sprayer base  160  for axial movement in response to water pressure. The deflector cap  162  may be spring biased, or alternatively gravity biased, into a closed position to prevent ingress of debris which may clog the spray head and prevent operation. The spray base  160  includes a center aperture  164  that accepts a deflector cap mounting stem  166 . The deflector mounting stem  166  has a length L that establishes a lift off height H of the deflector cap  162  relative to the sprayer base  160 . The lift off height H is based on the diameter of the grain dryer  112 , along with a minimum water deliver volume and pressure. The lift off height H is configured such that the water spray pattern is a generally horizontal spray pattern, as shown in  FIG. 19 , that reaches the interior wall  130  of the grain dryer  112 . The water spray further has sufficient force and volume to both cascade down the interior wall  130  and penetrate through the exterior wall  132  into the grain columns  126 . The water cascading along the interior wall  130  tends to draw heat away from the burning grain and lowers the amount of energy available to maintain or escalate combustion. The water that ingresses into the grain column  126  further dampens and extinguishes smoldering or burning material. 
         [0040]    The spray base  160  includes a diffuser, shown generally at  168 , that breaks up and directs the incoming water stream such that the water spray pattern is a generally horizontal spray pattern radiating  360  degrees within the dryer  112 . As shown in  FIG. 21 , the diffuser  168  includes four fins  170  that define water flow quadrants. Though shown as having four fins, any suitable number of fins  170  may be used. When the water stream is separated into smaller discrete sections, the stream is easier to direct horizontally from a substantially vertical input flow to the spray head  160 . Additionally, the spray pattern is generally evenly dispersed over the  360  degree area. The spray base  160  further includes an expanding tapered outlet  172  that permits the water to spray horizontally or generally in a radial direction toward the interior walls  130  of the grain columns  128 . 
         [0041]    While the invention has been described with reference to particular embodiments, it should be understood that various changes may be made and equivalents may be substituted for elements thereof without departing from the essential scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments, but that the invention shall include all embodiments falling within the scope of the claims.