Abstract:
A fast response residential sprinkler assembly includes a sprinkler body having a base and a frame extending from the base. The base has a passage extending therethrough defining an inlet and an outlet. A deflector is mounted to the frame and spaced from the outlet, which is configured to deflect fluid flowing from the outlet in a radial pattern. A trigger assembly extends between the frame and the base and is adapted to seal the outlet and release the seal when a temperature associated with a fire condition is detected. In addition, the sprinkler body is configured such that a ratio of the flow in gallons per minute from the outlet divided by the square root of the pressure in pounds per square inch gauge of the fluid supplied to the inlet is in a range of 4 to 6.

Description:
This application claims priority from U.S. provisional application Ser. No. 60/682,886, filed on Feb. 12, 2004, entitled FAST RESPONSE SPRINKLER ASSEMBLY FOR A FIRE EXTINGUISHING SYSTEM, by Applicant Shawn G. Orr, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a sprinkler and more particularly to an automatic residential sprinkler. 
     Automatic sprinklers have long been used to disperse a fluid to control a fire. Typically, the fluid utilized in such systems is water; although systems have also been developed to disburse foam and other materials. Historically, sprinkler assemblies include a solid metal base connected to a pressurized supply of water and a deflector that is used to disperse the water flow. The deflector is typically spaced from the outlet of the base by a frame. A trigger assembly is mounted between the base and a seal, which is positioned over the orifice of the base, to hold the seal in place over the orifice to thereby seal the orifice. When the temperature surrounding the sprinkler assembly is elevated to a temperature associated with a fire condition, the trigger assembly releases the seal and water is allowed to flow from the orifice of sprinkler assembly. 
     “Fast” sprinkler assemblies are those sprinkler assemblies that deliver fire suppressant over a shorter response time than standard sprinklers. A measurement of a sprinkler&#39;s response time is referred to as a reaction time indices (“RTI”), which for fast sprinklers is typically less than 100 m 1/2 sec 1/2 . For residential sprinklers, the current standards specify a maximum RTI of 50. 
     SUMMARY OF THE INVENTION 
     The present invention provides a fast sprinkler assembly that can achieve the desired minimum flow rates for residential sprinklers but at reduced water supply pressures that heretofore known. 
     In one form of the invention, the sprinkler assembly of the present invention includes a sprinkler head body configured for attachment to a fire extinguishing fluid supply line. The sprinkler head body is formed with an orifice in fluid communication with the fire extinguishing fluid supply line, and has a K value in a range of about 4 to 6 and, more preferably, in a range of about 4.9 to 5.6, and, most preferably about 5.2. A trigger assembly, which is coupled to the sprinkler head body, exerts a sealing force upon a sealing assembly. It has been found that providing a residential sprinkler head body with a K value of about 4 to 6 and, more preferably, in a range of about 4.9 to 5.6, and, most preferably about 5.2 results in a fast response sprinkler assembly that provides minimum flows using lower pressures that heretofore known that is particularly suitable for use as a residential sprinkler where suppression and/or extinguishment of a fire is required. 
     According to one form of the invention, a sprinkler assembly includes a sprinkler body having a base and a frame extending from the base. The base has a passage extending therethrough defining an inlet and an outlet. A deflector is mounted to the frame and spaced from the outlet, which is configured to deflect fluid flowing from the outlet in a radial pattern. A trigger assembly extends between the frame and the base and is adapted to seal the outlet and release the seal when a temperature associated with a fire condition is detected. The sprinkler body is configured such that a ratio of the flow in gallons per minute from the outlet divided by the square root of the pressure in pounds per square inch gauge of the fluid supplied to the inlet is in a range of about 4 to 6 and, more preferably, in a range of about 4.9 to 5.6, and, most preferably, about 5.2. 
     In one aspect, the deflector includes a plurality of slots having varying dimensions. For example, the deflector includes a generally planar member having a perimeter with the slots extending into the plane of planar member from its perimeter. 
     In a further aspect, each slot has a depth measured from the perimeter of the planar member. Preferably, the depths of the slots vary. For example, the depths may alternate between a first depth and a second depth, with the first depth being greater than the second depth. 
     In a further aspect, the planar member is circular, with the slots arranged such that their longitudinal axes align on respective radii of the planar member. For example, the slots may be arranged so that the longer slots align along radii extending through 0 degrees, 90 degrees, 180 degrees, and 270 degrees. In preferred form, the arms of the frame are aligned with a pair of the longer slots. The number of slots may vary. For example, the deflector may include twelve long slots and twelve shorter slots. 
     The present invention provides a fast response sprinkler assembly capable of discharging a sufficient output of water or other fire extinguishing fluid, and effectively alters the trajectory of the water so as to develop a spray distribution pattern about a pre-selected area using minimum flows and lower pressures than heretofore known. 
     These and other features and advantages of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a fast response sprinkler assembly of the present invention; 
         FIG. 2  is side elevation view of the sprinkler assembly depicted in  FIG. 1 ; 
         FIG. 3  is a sectional view of the sprinkler assembly taken along line III-III of  FIG. 2 ; 
         FIG. 4  is a sectional view of the sprinkler assembly taken along line IV-IV of  FIG. 2 ; 
         FIG. 5  is an enlarged side view of the bulb holder of the trigger assembly; 
         FIG. 6  is top plan view of the bulb holder of  FIG. 5 ; 
         FIG. 7  is a sectional view taken along line VII-VII of  FIG. 6 ; 
         FIG. 8  is a similar view to  FIG. 6  with the spring seal mounted to the bulb holder; 
         FIG. 9  is a similar view to  FIG. 7  with the spring seal mounted to the bulb holder; 
         FIG. 10  is a perspective view of the sprinkler head body of the sprinkler assembly with the deflector and trigger assembly removed; 
         FIG. 11  is a plan view of the sprinkler head body of  FIG. 10 ; 
         FIG. 12  is a side view of the sprinkler head body of  FIG. 10 ; 
         FIG. 13  is plan view of the deflector mounted to the sprinkler head body; 
         FIG. 14  is a plan view of the deflector; 
         FIG. 15  is similar view to  FIG. 14 ; 
         FIG. 16  is partial fragmentary plan view of the deflector; 
         FIG. 17  is a partial exploded view of the sprinkler assembly of the present invention incorporating a cover assembly; and 
         FIG. 18  is an enlarged elevation view of the cover assembly of  FIG. 17 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , the numeral  10  generally designates a sprinkler assembly of the present invention. As will be more fully described below, the sprinkler assembly comprises a fast response sprinkler assembly that generates a sufficient flow rate of water during the initial stage of fire development and develops an optimum spray distribution pattern capable of delivering an actual delivered density in excess of the required delivered density for a given fuel package to thereby permit a fire to be suppressed or extinguished. Although the sprinkler head of the present invention may be used to protect any area, it is particularly suited for use within a residential area where the ceilings are substantially smooth, flat, and horizontal. 
     As best seen in  FIG. 1 , sprinkler assembly  10  includes a sprinkler body  12 , a deflector  14 , and a trigger assembly  16 . Body  12  includes a base  18  and a frame  20  to which deflector  14  is mounted. Base  18  includes an externally threaded portion  18   a , which allows sprinkler body  12  to be threaded onto a fire extinguishing fluid supply line or pipe. 
     In the illustrated embodiment, trigger assembly  16  includes a frangible bulb  22 , which extends between base  18  and frame  20  and which is held in place and further urged toward outlet opening  24  of base  18  by a compression screw  26  to thereby maintain the seal on the outlet opening  24 , which when opened enables the flow of fire extinguishing fluid through base  18 , as will be more fully described below. Most preferably, for a ½ ″NPT sprinkler assembly, opening  24  is in a range of about 0.40 to 0.50 and, more typically, in a range of about 0.420 to 0.426 inches in diameter. 
     As best seen in  FIG. 3 , bulb  22  is seated and held in outlet opening  24  by a bulb holder  30 , which in turn urges a ring-shaped or annular spring seal  32  to seal outlet opening  24  under the force of the bulb. Referring to  FIGS. 5-9 , bulb holder  30  comprises a cup-shaped member  33  with an annular rim  34  for receiving an annular insert  36 . Insert  36  includes a central opening  36   a  that is sized to receive the lower end of bulb  22 , which has a narrowed cross-section to form a shoulder  22   a  ( FIG. 3 ) in the bulb, but sized small enough so that shoulder  22   a  rests on insert  36  so that bulb  22  is supported in cup-shaped member  33  by insert  36 . 
     Positioned around cup-shaped member  33  is spring seal  32 , which seals opening  24  when compressed against base  18  by cup-shaped member  33 . In an uncompressed state, spring seal  32  assumes a convex configuration ( FIG. 9 ). When compressed, however, spring seal  32  has a generally planar configuration ( FIG. 3 ). Spring seal  32  is preferably formed form a spring metal, such as nickel alloy, and, further, is coated with Teflon tape, which provides a seal. In this manner, when the compression force is released from spring seal  32 , spring seal  32  will return to its convex configuration and generate a force to push bulb holder  30  away from outlet opening  24 , which reduces the chances of the bulb holder interfering with the flow of fire extinguishing fluid from opening  24 . 
     As noted above, deflector  14  is mounted to frame  20 . As best seen in  FIG. 10-12 , frame  20  includes a pair of frame arms  42  and  44  that extend from base  18 . Frame arms  42  and  44  comprise generally L-shaped arms that are joined at their respective ends by a central boss  46 . Boss  46  includes an internally threaded aperture or bore  49  ( FIGS. 3 and 11 ) through which compression screw  26  is threaded to engage and compress bulb  22  against bulb holder  30 . In order to permit sprinkler body  20  to deliver an appropriate quantity of fire extinguishing fluid during the initial stages of fire development, bulb  22  preferably has a trigger temperature—that is a temperature at which the bulb explodes—between approximately 145° F. and 165° F., more preferably, between approximately 149° F. and 161° F., and, most preferably, approximately 155° F. 
     Referring to  FIGS. 13-16 , deflector  14  is formed from a generally planar, circular member  50 . For example, planar member  50  may a have a thickness in a range of 0.04 to 0.06 inches, more typically, in a range of 0.045 to 0.055 inches and, most typically, for a ½ NPT sprinkler, has a thickness of about 0.05 inches. Referring to  FIG. 4 , planar member  50  of deflector  14  is formed with a central aperture  50   a , such as a double hex opening, to attach deflector  14  to boss  46 . 
     To disperse the fire extinguishing fluid in the desired spray pattern, a plurality of spaced slots  52  are formed at the perimeter of member  50 , which extend into member  50  from its outer perimeter edge  50   b . In other words, the slots extend into member  50  so that they extend in and are arranged in the plane of member  50 . Each slot  52  has parallel sides  52   a  that extend into planar member  50  and terminate in a radiused end  52   b . Slots  52  may be uniform having uniform depths and radii of curvature at their respective ends or may be varied. For example, in the illustrated embodiment, the depths of the slots vary. For example, the depths may alternate between a first depth, a second depth, and a third depth with the first depth being greater than the second or third depths to define long slots  54 . And, the second depths are greater than third depths to define short slots  55  and  56 . 
     Further the radii of curvature of ends  52   b  may vary. For example, the depth of long slots  54  may fall in a range of about 0.18 to 0.3 inches, more typically in a range of about 0.20 to 0.28 inches, and most typically, in a range of about 0.22 to 0.24 inches. For example, for a 1¼ inch diameter deflector, the length of long slots may vary as noted but, more typically, fall in a range of about 0.22 to 0.24 inches and, most typically, approximately 0.23 inches. The depth of short slots  55  may fall in a range of about 0.08 to 0.16 inches, more typically, in a range of about 0.10 to 0.14 inches, and, most typically, in a range of about 0.11 to 0.13 inches. Similarly, for a 1¼ inch diameter deflector, the length of the short slots  55  will most typically be about 0.125 inches. The depth of slots  56  may fall in the range of about 0.14 to 0.24 inches, more typically, about 0.15 to 0.19 inches, most typically, about 0.16 to 0.18 inches. For a 1¼ inch diameter deflector, the length of slots  56  will most typically be about 0.17 inches. In addition, the radii of curvature ends  52   b  may vary. For example, the radii of curvature ends  52   b  may fall in a range of about 0.025 to 0.040 inches, more typically, in a range of about 0.028 to 0.038 inches, and most typically, in a range of about 0.03 to 0.035 inches. 
     In a further aspect, the planar member is circular, with the slots arranged such that their longitudinal axes align on respective radii of the planar member. For example, the slots may be arranged so that the longer slots align along radii extending through 0°, 90°, 180°, and 270°, as measured from one of the frame arms. In this manner, a pair of slots aligns with the frame arms ( FIG. 13 ). In preferred form, the arms of the frame are aligned with a pair of the longer slots. In addition, the number of slots may vary. For example, the deflector may include twelve long slots and twelve short slots. Further, each slot has a lateral dimension extending generally perpendicular to its respective radius of the circular member—one group of the slots may have smaller lateral dimensions than another group of the slots. 
     In another aspect, the radii of curvature of the slots located at 90° radius and 270° radius—in other words, the slots that extend along an axis orthogonal to the axis  20   a  ( FIG. 13 ) that extends between the frame arms—have smaller radii of curvature that the slots aligned with the frame arms and, further, smaller than the slots arranged there between. 
     Referring to  FIG. 15 , the radiused ends of the long slots are arranged to align with an inner diameter of member  50 . For example, ends  52   b  of slots  54  are aligned along a diameter in a range of about 0.75 to 0.83 inches, more typically, in a range of about 0.76 to 0.82 inches, and, most typically, in a range of about 0.78 to 0.80 inches. Ends  52   b  of slots  56  may be aligned along a diameter in a range of about 0.7 to 1.2 inches, more typically, in a range of about 0.8 to 1.1 inches, and most typically, in a range of about 0.85 to 0.95 inches. Most typically, the ends of slots  56  may be aligned along a diameter of about 0.9 inches. In this manner, the central portion of deflector  14  has a continuous circular surface having a diameter in a range of about 0.75 to 0.83 inches, and most typically in a range of about 0.78 to 0.80 inches. 
     Sprinkler assembly  10  is configured to have a discharge coefficient or “K value” (which is the measurement of the flow of water in gallons per minute through the sprinkler head divided by the square-root of the water pressure delivered to the sprinkler in pounds per square inch gauge) of between approximately 4 and 6, and preferably, approximately 5.2. It has been found that discharge coefficients of 5.6 and greater do not often achieve the desired minimum flow rates. In addition, it has been sprinklers with K factors of less than 4.9 may achieve the desired minimum flow rates but only at larger pressures. Discharge coefficient or K factor of a sprinkler is determined by flow testing. For example, the flow testing in increments of pressure from an initial pressure measurement and then decreased in the same increments back to the original pressure value. The K value then is determined from the actual flow in gallons per minute divided by the square-root of the pressure of the supplied water and psig at each increment, which are then averaged from all the incremental values which determines the K factor of the sprinkler. 
     As noted above, sprinkler assembly  10  is a fast response sprinkler. The response time of a sprinkler is referred to as “RTI”, which is a measure of thermal-sensitivity of a sprinkler. RTI is the product of the thermal time constant of the trigger in units of seconds times the square-root of the velocity of the gas across the trigger. Fast response sprinklers have a RTI typically less than 100 m 1/2 sec 1/2 . As noted above, sprinkler assembly  10  has a K factor in a range of about 4 to 6 and, more preferably, in a range of about 4.9 to 5.6, and, most preferably about 5.2. Further, sprinkler assembly  10  has an RTI in a range of about 33 to 50 and, more preferably, of less than about 38. Sprinkler  10  with a K factor between about 4 and 6 will supply about 20 gpm at a flow pressure of about 25 psi. Sprinkler  10  with a K factor of 5.2 will supply 20 gpm at just under 15 psi. In this manner, the sprinkler on the present invention provides greater flow for less pressure than heretofore known. Therefore, in Applicant&#39;s invention, a sprinkler of the present invention provides an optimally-sized sprinkler for residential use that will be able to cover the areas with the volume and flow pressure noted in the table provided below. This K value, in combination with deflector  30 , enables sprinkler assembly  10  to produce large, high momentum water droplets in a hemispheric pattern below deflector  30 . The size and momentum of the water droplets permits penetration of the fire plume and direct wetting of the fuel package surface in order to successfully suppress or extinguish a fire. 
     Furthermore, sprinkler assemblies  10  is preferably mounted such that deflector  14  is located ¾ inches to 4 inches below a ceiling, which is preferably substantially smooth, flat and horizontal. The area of coverage for a given flow and pressure are listed below: 
     
       
         
               
               
             
           
               
                   
               
               
                 Maximum Areas of Coverage 
                 Minimum Water Supply Requirements 
               
               
                   
               
             
             
               
                 12′ × 12′ 
                 14 gpm @ 7.2 psi 
               
               
                 14′ × 14′ 
                 14 gpm @ 7.2 psi 
               
               
                 16′ × 16′ 
                 14 gpm @ 7.2 psi 
               
               
                 18′ × 18′ 
                  17 gpm @ 10.7 psi 
               
               
                 20′ × 20′ 
                  20 gpm @ 14.8 psi 
               
               
                   
               
             
          
         
       
     
     Referring to  FIGS. 17 and 18 , sprinkler  10  may be installed as a concealed sprinkler, with a cover assembly  60  mounted over the deflector and over frame  20  of sprinkler assembly  10 . When mounted as a concealed sprinkler, sprinkler body  12  includes an adapter member  61 , which is mounted to the threaded portion  18   a  of base  18 . Adapter  61  provides a mounting surface for cover assembly  60  as will be more fully described below. 
     As best seen in  FIG. 18 , cover assembly  60  includes a base  64  and a cover  62 . Cover  62  is mounted to an annular rim  66  of base  64  by at least one of spring  68 . Adapter member  61  comprises an annular cup-shaped member with a downwardly depending annular wall  61   a  and an upper generally horizontal annular wall  61   b , which threads onto the threaded portion  18   a  of base  18 . Base  64  of cover assembly  60  includes an annular wall  70  with a plurality of inwardly projecting tabs  72 , which engage annular wall  61   a  and mount cover assembly  60  to adapter  61  to thereby position cover  62  over deflector  14  and the lower portion of frame  20 . 
     Cover  62  generally has a bell-shaped configuration with an outwardly extending rim  74  which extends over and covers annular flange  66  of base  64  and, further, provides a contact point for downwardly depending tabs  76  of base  64 . Similarly, rim  74  provides a contact point for spring  68 , which has a generally V-shaped cross-section with a lower portion of spring  68  compressing against rim  74  and the upper portion of spring  68  engaged with rim  66  of base  64  to thereby releasably couple cover  62  to base  64 . 
     While several forms of the invention have been shown and described, other forms will now be apparent to those skilled in the art. Therefore, it will be understood that the embodiments shown in the drawings and described above are merely for illustrative purposes, and are not intended to limit the scope of the invention, which is defined by the claims, which follow as interpreted under the principles of patent law including the doctrine of equivalents.