Patent Publication Number: US-9833649-B2

Title: Fire protection sprinkler

Description:
PRIORITY DATA 
     This application is a continuation of U.S. patent application Ser .No. 14/214,200 filed Mar. 14, 2014, which claims the benefit of priority to U.S. Provisional Patent Application No. 61/788,039, filed Mar. 15, 2013, each of which is incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This invention relates to fire protection sprinklers, and more particularly storage fire protection sprinklers preferably for installation in dry-pipe sprinkler systems. 
     BACKGROUND 
     In its 2013 publication of “NFPA 13: Standard for the Installation of Sprinkler Systems” (herein after “NFPA 13”), the National Fire Protection Association (NFPA) defines an automatic sprinkler as “a fire suppression or control device that operates automatically when its heat-activated element is heated to its thermal rating or above, allowing water to discharge over a specified area.” A known heat-activated element for use in an automatic sprinkler is a thermally responsive frangible bulb, as seen for example, in U.S. Pat. No. 5,967,238. An automatic sprinkler can be characterized by the physical dimensions and thermal characteristics, i.e., nominal temperature rating and Response Time Index (RTI), of its thermally responsive bulb. U.S. Pat. No. 5,967,238 describes a thermally responsive frangible bulb with a maximum bulb diameter of about 0.1 inch and a maximum bulb length of less than 1 inch. Other known thermally responsive bulbs are manufactured with a maximum length of more than ¾ inch, a maximum RTI of 90 meter sec 1/2 sec 1/2  (m 1/2 s 1/2 ) and a nominal temperature rating defined under NFPA 13 being any one of: (i) ordinary 135° F.-170° F.; (ii) intermediate 175° F.-225° F.; (iii) high 250° F.-300° F.; (iv) extra high 325° F.-375° F.; (v) very extra high 400° F.-475° F.; and (vi) ultra high 500° F.-575° F. 
     In addition to its thermally responsive bulb, an automatic sprinkler can also be characterized by its discharge characteristics. A sprinkler&#39;s discharge characteristics can be identified by a nominal K-factor which is defined as an average flow of water in gallons per minute through the internal passageway divided by a square root of pressure of water fed into the inlet end of the internal passageway in pounds per square inch gauge: Q=K√P where P represents the pressure of water fed into the inlet end of the internal passageway through the body of the sprinkler, in pounds per square inch gauge (psig); Q represents the flow of water from the outlet end of the internal passageway through the body of the sprinkler, in gallons per minute (gpm); and K represents the nominal K-factor constant in units of gallons per minute divided by the square root of pressure expressed in psig. Known nominal K-factors include (with the K-factor range shown in parenthesis): (i) 14.0 (13.5-14.5) GPM/(PSI) 1/2 ; (ii) 16.8 (16.0-17.6) GPM/(PSI) 1/2 ; (iii) 19.6 (18.6-20.6) GPM/(PSI) 1/2 ; (iv) 22.4 (2.13-23.5) GPM/(PSI) 1/2  ; (v) 25.2 (23.9-26.5) GPM/(PSI); (vi) 28.0 (26.6-29.4) GPM/PSI) 1/2 ; and (vii) 33.6 (31.9-35.28) GPM/(PSI) 1/2 . 
     For automatic sprinklers with a nominal K-factor of 16 GPM/(PSI) 1/2  and larger, the heat-activated element might be a strut and lever arrangement with a thermally responsive solder element. U.S. Pat. Nos. 5,609,211; 8,602,118; and 8,408,321 and U.S. Patent Publication No. 20080073088 generally show and describe sprinklers with a thermally actuated bulb with a nominal K-factor of 25.2 GPM/(PSI) or larger. Although these patents, for example U.S. Pat. No. 8,418,321, indicate that sprinklers having a nominal K-factor larger than 25.2 GPM/(PSI) 1/2  with a bulb-type trigger are applicable for the described dry-pipe sprinkler system, the patent does not describe any particular details of the glass bulb, bulb seating and/or applications for combining a sprinkler with a K-factor greater than 25.2 GPM/(PSI) 1/2  with a glass bulb. 
     SUMMARY OF THE INVENTION 
     Preferred embodiments provide a fire protection sprinkler for storage preferably in a dry-pipe sprinkler system. The preferred sprinkler includes a body defining an internal passageway extending along a sprinkler axis between an inlet end and an opposite outlet end, the internal passageway having a nominal K-factor greater than 16. The sprinkler preferably includes a pair of support arms each having a first end and a second end, the first end extending from the body; and a deflector axially supported and spaced from the outlet end by the pair of support arms. The sprinkler includes means for allowing the flow of water to flow from the outlet end of the internal passageway and be distributed by the deflector to control a fire in a rack storage arrangement of at least one of Class I-IV and Cartoned Unexpanded Group A Plastics commodity as defined by NFPA 13 (2013 Edition) stored at a nominal 40-ft storage height when the sprinkler is disposed in a grid of sprinklers in a dry-pipe piping system proximate a nominal 45 ft. high ceiling or higher, 
     The preferred means includes a closure assembly having a body with a first surface and a second surface spaced from the first surface. The first surface preferably defines a blind bore that includes an entrance at the first surface and a terminal end formed between the first and second surfaces. The second surface is disposed in the passageway so as to axially align the body along the sprinkler axis. A thermally responsive glass bulb is disposed substantially coaxially with the sprinkler axis. The glass bulb has a first end disposed within the blind bore and contiguous with the seat of the blind bore to define a first seat diameter. A second end of the glass bulb defines a second seat diameter. A bulb length between the first seat diameter and the second seat diameter is greater than the length of the internal passageway between an inlet end and an opposite outlet end. The glass bulb has a maximum wall thickness less than the difference between the bulb length and the passageway length. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate exemplary embodiments of the invention and, together with the general description given above and the detailed description given below, serve to explain the features of the exemplary embodiments of the invention. 
         FIG. 1  is an elevation and plan view of a preferred sprinkler assembly; 
         FIG. 2  is a cross-sectional view of the sprinkler of  FIG. 1 ; 
         FIG. 3  is a detailed partial cross-sectional view of the closure and trigger assemblies in the sprinkler assembly of  FIG. 1 ; 
         FIG. 4  is a plan view of the closure assembly for use in the sprinkler assembly of  FIG. 1 , 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     According to a preferred embodiment, a fire protection sprinkler assembly  10  is provided for use in protection of at least extra hazard and high piled storage occupancies. Referring to  FIGS. 1 and 2 , an upright-type fire protection sprinkler assembly  10  includes a one-piece frame  12  having a body  14  defining an internal passageway  16  that extends between an inlet end  18  and an opposite outlet end  20  to define a sprinkler axis A-A. The fire protection sprinkler  10  has a nominal discharge coefficient or K-factor of greater than about 16.0. In preferred embodiments, the nominal K-factor can be between about 16.8 and about 28.0, preferably between about 22.4 and about 28.0, more preferably between about 25.2 and about 28.0, and most preferably a nominal K-factor of 25.0. Accordingly, the nominal K-factor can be between a nominal 168 GPM/(PSI) 1/2  and a nominal 28.0 GPM/(PSI) 1/2 , is more preferably at least 25.2 GPM/(PSI) 1/2 , and is even more preferably greater than 28.0 GPM/(PSI) 1/2 . In one aspect, the nominal K-factor is preferably over 28.0 GPM/(PSI) 1/2  by a whole multiple of 5.6 (plus: or minus 5%) such as for example a nominal K-factor of 33.6 GPM/(PSI) 1/2  (31.9-35.28). 
     Cooperating threads  22  provided on the outside surface  24  of the body in the region of the inlet end  18  and in the internal passageway  16  permit the sprinkler  10  to be coupled to a threaded fitting adapted for connection to a supply pipe, for delivery of water, or other fire fighting fluid. The outlet end  20  of internal passageway  16  has an axis, A. At the outlet end  20  of the body  14 , the frame  12  is enlarged into a hexagonally shaped, circumferential flange  26 , with major, opposite parallel flat surfaces or “flats.” The flats are positioned for engagement with an open-ended wrench or a specially designed sprinkler wrench having a hexagonally shaped recess for threading and tightening the sprinkler  10  into the threaded fitting, TF, for connection to the fluid supply pipe. 
     The frame  12  preferably includes a pair of support arms  32 ,  34  extending generally away from opposite sides of the outlet end  20  of the body  14  and meeting to form an apex  36 . The apex is preferably aligned with axis A-A and axially spaced from the outlet end  20  of the internal passageway. A deflector  38 , engaged with apex  36  is axially spaced from the outlet end  20  to distribute a flow of fire-fighting fluid, e.g., water, from the outlet end  20  about the sprinkler  100 . The deflector  38  is preferably centrally and coaxially aligned with the sprinkler axis A-A. The deflector can be any suitable deflector to provide a desired spray pattern. Referring to  FIG. 1 , the deflector is generically shown with a planar portion centrally disposed and perpendicular to the sprinkler axis A-A. Water discharged from the outlet end  20  impacts the central portion for at least radial distribution of the fluid toward to the periphery (not shown) of the deflector. In one aspect of the preferred sprinkler assembly  10 , the preferred pair of arms  32 ,  34  are disposed about the sprinkler body  14  to so as to preferably define a plane P 1  which bisects the deflector  38 . 
     The sprinkler  100  and its deflector  38  are preferably configured to provide an automatic sprinkler assembly for the protection of a storage occupancy. Accordingly, the sprinkler  10  includes means for allowing the flow of water to flow from the outlet end  20  of the internal passageway  16  and be distributed by the deflector  38  to control a fire in a rack storage arrangement. 
     More preferably, the sprinkler  10  includes means for allowing the flow of water to flow from the outlet end  20  and be distributed by the deflector  38  to address a fire in a rack storage arrangement of at least one of Class I-IV and Cartoned Unexpanded Group A. Plastics commodity as defined by NFPA 13 (2013 Edition) stored at a nominal 40-ft storage height when the sprinkler is disposed in a grid of sprinklers in a dry-pipe piping system and installed proximate at a nominal 45 ft, high ceiling. Accordingly in one preferred aspect, the sprinkler  10  includes means for allowing the flow of water to flow from the outlet end  20  for distributed in the protection of a stored commodity at least at a nominal 40-ft storage height when the sprinkler is disposed in a grid of sprinklers in a dry-pipe piping system and installed proximate at a nominal 45 ft. high ceiling. The preferred means for allowing the fluid flow from the outlet  20  for distribution includes a closure assembly  26  with a heat-responsive trigger  30  mounted to the sprinkler frame  12  to maintain the sprinkler assembly  10  in an unactuated, standby or non-fire condition, e.g., as shown in  FIGS. 1 and 2  to releasably secure the outlet end  20  of the internal passageway  16  against a flow of water. A preferred heat-responsive trigger  30  of the sprinkler  10  and its actuation is defined by its nominal temperature rating and Response Time Index, or RTI. The trigger  30  is configured to actuate at or define a preferred nominal temperature rating of 286° F. and define a preferred RTI of 135 meter 1/2 sec 1/2  (m 1/2 s 1/2 ) to about 160 meter 1/2 sec 1/2  (m 1/2 s 1/2 ). The trigger may have another nominal temperature rating provided it is suitable for the hazard, occupancy or storage being protected, including, for example as defined under NFPA 13: (i) ordinary 135° F.-170° F.; (ii) intermediate 175° F.-225° F.; (iii) high 250° F.-300° F.; (iv) extra high 325° F.-375° F.; (v) very extra high 400° F.-475° F.; and (vi) ultra high 500° F.-575° F. Moreover, the heat-responsive trigger  30  can define alternate ranges of RTI, which can range from at least 130 meter 1/2 sec 1/2  (m 1/2 s 1/2 ) to 160 meter 1/2 sec 1/2  (m 1/2 s 1/2 ), preferably at least 135 meter 1/2 sec 1/2  (m 1/2 s 1/2 ) to about 160 meter 1/2 sec 1/2  (m 1/2 s 1/2 ), more preferably 150 meter 1/2 sec 1/2  (m 1/2 s 1/2 ) to about 160 meter 1/2 sec 1/2  (m 1/2 s 1/2 ), and is even more preferably 160 meter 1/2 sec 1/2  (m 1/2 s 1/2 ). In response to a predetermined temperature condition indicative of a fire, the heat-responsive trigger  30  actuates, releasing closure assembly  26 , thereby allowing the flow of water supplied to the inlet end  18 , through the internal passageway  16 , and out through the outlet end  20 . 
     Preferred embodiments of the closure assembly  26  and the heat-responsive trigger  30  are shown in  FIG. 2  and the detailed view of  FIG. 3 . The closure assembly  26  preferably includes a body  126  having first surface  128   a  facing the deflector and a second surface  128   b  spaced opposite the first for location within the internal passageway  16  of the sprinkler frame  12  to preferably axially align the body  126  along the sprinkler axis A-A. The first surface  128   a  preferably defines a blind bore  130  disposed along the sprinkler axis. The blind bore  130  is defined by an entrance  132  formed at the first surface  128   a  and a terminal end  134  formed between the first and second surfaces  128   a ,  128   b . As located in the passageway  16 , the second surface  128   b  preferably includes a first portion  136  oblique to the sprinkler axis A-A and a second portion  138  substantially perpendicular to the sprinkler axis A-A. As seen in  FIG. 4 , the body  126  includes a perimeter  140  disposed or circumscribed about the sprinkler axis A-A. The perimeter  140  preferably includes a preferred first section  140   a  disposed between the first surface  128   a  and the terminal end  134  of the blind bore  130  and a second section  140   b  between the terminal end  134  of the blind bore  130  and the second surface  128   b . Referring again to  FIG. 3 , the closure assembly  26  further preferably includes a metallic annulus  150  disposed on a support surface  142  between the first surface  128   a  and the second surface  123   b  of the body  12  to seal internal passageway  16 . The metallic annulus  150  can be embodied as a Belleville Spring, to bias the body  126  distally out of the outlet end  20  of the passageway  16 . The annulus  150  is preferably annular having a central portion surrounding the body  126  between the first surface  128   a  and the second surface  128   b.  Further preferably surrounding the body  26  to facilitate ejection of the annulus and body upon thermal actuation is a spring member  152  having a first end  152   a  and an opposite second end  152   b , as seen in  FIG. 4 , which are disposed about the passageway  16 . The first and second ends  152   a ,  152   b  are engaged with the arms  32 ,  34 . 
     The heat responsive trigger  30  is preferably embodied as a thermally responsive glass bulb  230  having a first end  232   a  and a second end  232   b  to define a trigger axis preferably substantially coincident or aligned with the sprinkler axis The first end  132   a  is preferably disposed within the blind bore  130  of the sealing body  126  and contiguous with the seat  132  of the blind bore  130 . The second end  232   b  of the bulb  230  is preferably contiguous with a compression member  37 . The first end  232   a  of the bulb  230  defines a first a seat diameter D 1  and the second end  232   b  defines a second seat diameter D 2 . The first seat diameter D 1  is preferably less than the second seat diameter D 2 . In one particular embodiment, the first diameter seat D 1  is about three millimeters (3 mm.) preferably equal to the diameter of the spherical recess at the distal end of the compression member  37 . The second diameter seat D 2  is about 5.5 mm preferably equal to the diameter of the seat  132  of the blind bore  130 . Accordingly, the first and second ends  232   a ,  232   b  preferably define a preferred ratio of first to second seat diameter D 1 :D 2  which ranges from about 0.5:1 to about 0.6:1. The bulb  230  further preferably defines a bulb length L 1  between the first and second ends  232   a ,  232   b . The passageway  16  of the sprinkler frame  12  defines a passageway length L 2  that extends between the inlet end  18  and the outlet end  20 . In a preferred embodiment of the sprinkler assembly  10 , the bulb length L 1  is greater than the passageway L 2 . In one preferred embodiment of the bulb  230 , the bulb length is preferably greater than one inch and is more preferably about 1.5 inches (40 mm.). The passageway length L 2  is preferably ranges from about 1.5 inches to about 1.3 inches, preferably about 1.25 inches and is more preferably 1.28 inches. The glass bulb  230  includes an internal surface to define a inner space for holding the thermally responsive liquid. Accordingly, the bulb  230  preferably defines a wall thickness between the outer and inner surface of the bulb. The bulb  230  preferably defines a maximum wall thickness that is less than the difference between the bulb length L 1  and the passageway length L 2 . In one preferred embodiment of the bulb  230 , the maximum wall thickness is about 1 mm, to define a preferred ratio of maximum thickness to bulb length which can range from 1:30 to about 1:40, 
     A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, although in the presently preferred embodiment, as described above, the deflector is mounted to the body by a pair of support arms, other numbers of support arms are contemplated, e.g. one support arm, or three or more support arms. Where other than two support arms, arrayed at 180° are employed, a plane of the support arms means a plane generally through at least one support arm and through the axis, A. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.