Patent Publication Number: US-11383114-B2

Title: Sprinkler head

Description:
This application is a national phase entry under 35 U.S.C. § 371 of PCT Patent Application No. PCT/JP2017/042598, filed on Nov. 28, 2017, which is incorporated by reference. 
     TECHNICAL FIELD 
     The present invention relates to a fire extinguisher sprinkler head and, in particular, to a residential sprinkler head. 
     BACKGROUND ART 
     Sprinkler system is installed in a building. The Sprinkler system detects the heat of the fire and automatically operates to spray water to extinguish the fire. The sprinkler head has a nozzle thereinside, and the nozzle is connected to a pipe leading to a water supply source. The nozzle is in a closed state at normal times. If a fire occurs and the sprinkler head operates due to heat, the nozzle is opened so that the water filled in the pipe is discharged from the nozzle. The sprinkler head is provided with a deflector on the extension of the outlet of the nozzle. The deflector scatters water in all directions. The water striking the deflector is sprayed onto a predetermined area to control and extinguish the fire. 
     Sprinkler system is installed in commercial facilities, public facilities, residential houses, and the like, and the standard for the installation and construction of Sprinkler system is defined. In the United States, the National Fire Protection Association standards provides NFPA 13, which is the standard for the design and installation of Sprinkler system for building applications. Residential Sprinkler system standards are NFPA 13D and 13R. In addition, Underwriters Laboratories (UL LLC) develops UL 1626, which is the standard for residential sprinkler heads. 
     Existing residential sprinkler heads include U.S. Pat. Nos. 6,516,893 and 7,201,234. These sprinkler heads obtain a desired water spray pattern with the structure of the deflector. However, the shape of the deflector is complicated. One of the reasons is that the main body used in these residential sprinkler heads is commonly used with sprinkler heads of other specifications and, thus, changes in the structure of the main body are limited. 
     The water spray pattern is significantly influenced by the shape of the deflector. Furthermore, the water spray pattern is influenced to no small extent by a part of the main body which water discharged from the nozzle strikes. 
     CITATION LIST 
     Patent Literature 
     PTL 1: U.S. Pat. No. 6,516,893 
     PTL 2: U.S. Pat. No. 7,201,234 
     SUMMARY OF INVENTION 
     Technical Problem 
     Accordingly, it is a first object of the present invention to provide a sprinkler head capable of obtaining a desired water spray pattern with a simplified deflector shape. 
     A second object of the present invention is to provide a sprinkler head capable of passing a water spraying test and a fire extinguishing test defined by UL 1626 with a minimum flow rate. 
     Solution to Problem 
     In order to achieve the above objects, the present invention provides a sprinkler head having the following structure. The sprinkler head includes a main body having a nozzle connected to a water supply pipe, the nozzle is provided inside of the main body, a pair of arms extending from the main body in a water discharge direction of the nozzle, where a tip of each of the arms is connected to a boss that has a columnar shape, that is disposed on a central axis of the nozzle, and that has a female screw thereinside, an impress screw screwed into the female screw and having a tip protruding toward the nozzle, and a deflector having a disc shape and mounted at a front end of the boss. The deflector has a plurality of slits having an equal length cut around a peripheral edge of the deflector at equal intervals, from an outer periphery of the deflector toward the central axis of the nozzle, and a length of a first slit provided at a position closest to a line that perpendicularly intersects with a plane passing through the pair of arms and that passes through the central axis of the nozzle is greater than the length of the other slits. 
     Furthermore, the sprinkler head has the following structure. The sprinkler head includes a main body having a nozzle connected to a water supply pipe, the nozzle is provided inside of the main body, a pair of arms extending from the main body in a water discharge direction of the nozzle, where a tip of each of the arms is connected to a boss that has a columnar shape, that is disposed on a central axis of the nozzle, and that has a female screw thereinside, an impress screw screwed into the female screw and having a tip protruding toward the nozzle, and a deflector that has a disc shape, that is mounted at a front end of the boss, and that has a plurality of slits cut around a peripheral edge of the deflector. An outer peripheral end of the boss adjacent to the nozzle has a shape of a rounded surface, and an extension line along a shape of the tip of the impress screw is in close vicinity of or in contact with the rounded surface. 
     The above-described sprinkler head is a residential sprinkler head, and the value of the K factor derived from the flow rate and the water discharge pressure of the nozzle is 3 to 5.8. A desired water spray pattern can be obtained with the shapes of the deflector, the boss having the deflector mounted thereon, and the impress screw provided in the boss. More specifically, by adopting a structure in which turbulence does not easily occur at the tip of the impress screw that the water discharged from the nozzle strikes first and the boundary between the impress screw and the boss, the shape of a slit of the deflector is simplified. As a result, the control of the water spray pattern is facilitated. 
     The tip of the impress screw protrudes toward the nozzle, and the shape of the tip is sharp, which provide the effect of reducing the resistance of the flow of water and uniformly distributing the water that strikes the tip in all directions. The impress screw has a slope surface from the tip thereof toward the boss, and the water flows along the slope surface. The extension line extending along the slope surface is in close vicinity of or in contact with the rounded surface of the outer peripheral end of the boss and, thus, the water flows smoothly along the rounded surface of the outer peripheral end of the boss from the slope surface. Thereafter, the flow of water that has passed through the outer periphery of the boss and has reached the flat surface of the deflector passes through the slits provided in the outer periphery of the deflector at equal intervals, and the flow of water scatters toward a floor surface. Alternatively, the flow of water reaches the outer periphery of the deflector and scatters toward a wall surface. 
     At this time, the direction of the line that perpendicularly intersects with the plane passing through the pair of arms and that passes through the center axis of the nozzle is the position at which the flow of water is least influenced by the arms. There is no obstacle that prevents the flow of water, and the flow is smooth. As a result, the momentum of the water increases, and the water is spread farther away, so that the amount of water spray exceeding the prescribed wall wetting height can be obtained for the wall surface. However, at the same time, the amount of water spray in a short distance range immediately below the sprinkler head tends to be insufficient. To address this disadvantage, by making the length of the slit at this position greater than the length of the other slits to guide the flow of water onto the floor surface, the amount of water spray in the short distance range can be increased. In this manner, the water can be uniformly sprayed onto the floor surface. In addition, a desired wetting height can be obtained for the wall surface. 
     Advantageous Effects of Invention 
     As described above, according to the present invention, a desired water spray pattern can be obtained with a simplified deflector shape by reducing the occurrence of turbulence by using the tip of an impress screw and a boss. Furthermore, according to the sprinkler head having the above configuration, a sprinkler head can be achieved that is capable of clearing the water spray test and the fire extinguishing test defined by UL 1626 with the smallest flow rate. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an external view of a sprinkler head according to the present invention. 
         FIG. 2  is a cross-sectional view taken along a line II-II of  FIG. 1 . 
         FIG. 3  is an enlarged view around a boss illustrated in  FIG. 2 . 
         FIG. 4  is a plan view of a deflector. 
         FIG. 5  is a diagram illustrating a positional relationship between a sprinkler head and a water spray test facility. 
         FIG. 6  is an enlarged view of a slit portion illustrated in  FIG. 4 . 
         FIG. 7  illustrates an example of a modification of the deflector illustrated in  FIG. 4 . 
         FIG. 8  is a cross-sectional view taken along a line  7 - 7  of  FIG. 1 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     As illustrated in  FIGS. 1 and 2 , a sprinkler head S 1  according to the present invention includes a main body  1 , a deflector  2 , a valve  3 , and a thermal decomposition unit  4 . 
     The main body  1  has a hollow shape. The main body  1  is provided with a male screw  11  on the outer side to connect to a pipe in the ceiling and is provided with a nozzle  12  on the inner side. In terms of the size of the nozzle  12 , a K factor derived from the flow rate and the water discharge pressure of the nozzle  12  is in the range of 3 to 5.8. According to the present embodiment, the value of the K factor is 4.9. The size of the male screw  11  connected to the pipe is NPT1/2 or R1/2. 
     In the vicinity of the outlet of the nozzle  12 , a substantially rectangular base  13  is mounted, and a pair of arms  14  extending from the base  13  in the water discharge direction of the nozzle  12  is mounted. The arm  14  has a straight portion  14 A extending substantially in parallel to a central axis A of the nozzle and an intersecting portion  14 B connected from the end of the straight portion  14 A to a boss  15  disposed on the central axis A of the nozzle  12 . As illustrated in  FIG. 3 , the intersecting portion  14 B is thinner than the straight portion  14 A, and the cross-sectional shape is elliptical. 
     The boss  15  has a tapered cylindrical shape, and the deflector  2  is mounted at the front end of the boss  15 . A diameter D 1  of the boss  15  at the end in contact with the deflector  2  is 9 mm to 10 mm. The outer diameter of the end of the boss  15  adjacent to the nozzle  12  is smaller than the diameter D 1  at the end adjacent to the deflector  2 . The outer peripheral end  15 A of the boss  15  adjacent to the nozzle  12  has a shape of a rounded surface, and the radius of the rounded surface is in the range of 1 mm to 3 mm. According to the present embodiment, the radius of the rounded surface is 2 mm. 
     A female screw  15 B is provided inside the boss  15 , and an impress screw  16  is screwed into the female screw  15 B. A tip  16 A of the impress screw  16  is sharply pointed and has a slope surface  16 B. The tip  16 A faces the nozzle  12 , and an angle α of the slope surface  16 B is in the range of 80° to 100°. According to the present exemplary embodiment, the angle α is 90°. The apex of the tip  16 A is spherical. It is desirable that the radius of the spherical surface be 2 mm or less. According to the present embodiment, the radius of the spherical surface is 1 mm or less. 
     The impress screw  16  has a function of urging the valve  3  toward the nozzle  12  via the thermal decomposition unit  4 . In  FIG. 3 , an extension line  16 C extending along the slope surface  16 B of the tip  16 A of the impress screw  16  is in close vicinity of or in contact with the rounded surface of an outer peripheral end  15 A of the boss  15 . Accordingly, when water flowing along the surface of the tip  16 A passes through the outer peripheral end  15 A, the outer peripheral end  15 A does not interfere with the flow of water, which prevents the occurrence of turbulence flow. At this time, a gap “a” between the slope surface  16 B of the impress screw  16  and the end surface of the boss  15  adjacent to the nozzle  12  is set to 2 mm or less, and more preferably is set to 1 mm or less. If the gap is greater than this value, a turbulence flow is likely to occur. 
     The deflector  2  illustrated in  FIG. 4  has a disc shape, and its outer diameter D 3  is in the range of 28 mm to 32 mm. According to the present embodiment, the outer diameter D 3  is 30 mm. A plurality of slits  21  are provided on the peripheral edge of the deflector  2 . Each of the slits  21  is formed on a straight line that extends from the peripheral edge of the deflector  2  and passes through the center point of the deflector  2 . In  FIG. 4 , the arms  14  indicated by a short dashed line are disposed on a straight line B. The straight line B represents a plane passing through the pair of arms  14 , and slits  22  (first slits) are provided on a line C that perpendicularly intersects with the straight line B and passes through the central axis A. 
     The slit  22  is longer than the slit  21 , and the length of the slit  21  is in the range of 4.5 mm to 7 mm. According to the present embodiment, the length of the slit  21  is 5.8 mm. The length of the slit  22  is in the range of 5.5 mm to 8 mm. According to the present embodiment, the length of the slit  22  is 6.3 mm. 
     The distance between each of the slits  21  and  22  and the neighboring slit thereof is the same on the outer periphery of the deflector  2 . The total number of the slits (the slits  21  and the slits  22 ) is in the range of 16 to 24. According to the present embodiment, the total number of the slits is 20. Widths W 1  of the slits  21  and  22  are all the same and are set in the range of 1 mm to 2 mm. According to the present embodiment, the widths W 1  are all 1.4 mm. The deflector  2  is symmetrical with respect to the line B. In addition, the deflector  2  is symmetrical with respect to the line C. 
     In the positional relationship between the sprinkler head S 1  and a water spray test facility illustrated in  FIG. 5 , the sprinkler head S 1  is installed on a ceiling in a corner cell of a plurality of water sampling cells M, which are arranged vertically and horizontally without any gap. In the drawing, the arm  14  is disposed in the direction of an arrow X, and the slits  22  are disposed in the direction of an arrow Y. According to UL 1626, it is necessary to ensure a predetermined amount of water or more for each of the cells M. In this test facility, the amount of water spray can be measured for ¼ of the protection area of the sprinkler head S 1 . The water spray pattern has a substantially circular shape due to the shape of the deflector  2 . Ideally, it is desirable that water be uniformly sprayed onto all the water sampling cells within a quarter circle indicated by a short dashed line in  FIG. 5 . 
     However, the arms  14  interfere with the flow of the water discharged from the nozzle  12  and, thus, the flight distance of the water in the direction of the arrow X is shorter than that in the direction of the arrow Y. Conversely, in the direction of the arrow Y, the amount of water sprayed onto a region Y 1  distant from the sprinkler head S 1  tends to be large, and the amount of water sprayed onto a region Y 2  in front of the sprinkler head S 1  tends to be small. However, by adjusting the length of the slit  22 , the amount of water sprayed onto the region Y 1  can be decreased, and the amount of water sprayed onto region Y 2  can be increased. Thus, the water is sprayed substantially uniformly over all of the water spraying cells. In this manner, the amount of water sprayed onto each of the regions Y 1  and Y 2  can be freely controlled. 
     At this time, if the length of the slit  22  is more than 1 time but less than or equal to 1.5 times the length of the slit  21 , the distribution of water spray on the floor surface becomes uniform. If the length of the slit  22  exceeds 1.5 times the length of the slit  21 , the amount of water sprayed onto the region Y 2 , which is located substantially immediately below the sprinkler head S 1 , tends to increase excessively. 
       FIG. 6  is an enlarged view of the slits  21 . The minimum distance between two neighboring slits  21  is denoted by L 1 , and the maximum distance is denoted by L 2 . Furthermore,  FIG. 6  illustrates an inscribed circle D 2  which the end of each of the slits  21  adjacent to the boss  15  is in contact with. At this time, the ratio of between the minimum slit distance L 1  and the maximum slit distance L 2  (L 1 /L 2 ) and the ratio between the minimum distance between the slits  21  and the width W 1  of the slit  21  (L 1 /W 1 ) have an influence on the water spray density of the floor surface. It is desirable that the value of L 1 /L 2  be within the range of 1.8 to 2 and the numerical value of L 1 /W 1  be within the range of 1.15 to 1.3 in accordance with the shape of the slit  21 . 
     For the sprinkler head S 1  illustrated in  FIG. 5 , to measure the height of a wall surface wetted by spraying water (the distance from the ceiling surface to the wet location on the wall surface; hereinafter referred to as a “wall wetting height”), wall surfaces are provided corresponding to the locations denoted by alternate long and short dash lines. The inscribed circle D 2  which the end of each of the slits  21  adjacent to the boss  15  is in contact with has an influence on the wall wetting height. If the diameter of the inscribed circle D 2  is set to 18 mm to 19.5 mm, the wall wetting height is in the range of 20 inches to 35 inches. 
     In the above description, there is a trade-off relationship between the amount of water sprayed onto the floor surface (the water spray density) and the wall wetting height. Accordingly, to satisfy both the amount of water sprayed onto the floor surface and the wall wetting height, it is desirable that the slit  21  be configured such that the above-described ratio between the minimum slit distance L 1  and the maximum slit distance L 2  (L 1 /L 2 ), the ratio between the minimum distance between the slits  21  and the width W 1  of the slit  21  (L 1 /W 1 ), and the diameter of the inscribed circle D 2  are within the above-described ranges. 
       FIG. 7  illustrates a modification of the deflector  2  in which slits  22  each adjacent to a line C are provided. In  FIG. 7 , four slits  22  are provided, and the total number of slits including the slits  21  and the slits  22  is 18. Widths W 2  of the slits  21  and  22  are all the same and are set in the range of 1 mm to 2 mm. According to the present embodiment, the width W 2  is 1.7 mm. The distance b between the line C and each of the two slits  22  and  22  adjacent to the line C is the same. 
     The valve  3  closes the outlet of the nozzle  12  at normal times. The valve  3  includes a valve cap  31 , a disk  32 , and a disc spring  33 . The valve cap  31  has a cylindrical shape and has a spherical bottom  31 A at one end. The other end is enlarged in diameter and has a step  31 B formed therein. 
     The disk  32  is placed on the inner peripheral side of the step  31 B. The disk  32  has a recess  32 A at the center thereof, and the recess  32 A is engaged with one end of a columnar support  42  of a thermal decomposition unit  4 . 
     A disc spring  33  is locked on the outer peripheral side of the step  31 B. The disc spring  33  is inserted from the bottom  31 A of the valve cap  31 . The surface of the disc spring  33  is covered with a fluorine resin. The outer peripheral edge of the disc spring  33  is disposed at the end of outlet of the nozzle  12 . When the impress screw  16  is screwed into the female screw  15 B of the boss  15 , the disc spring  33  is pressed via the thermal decomposition unit  4  and is crushed due to its elastic deformation. At this time, the fluorine resin functions as a sealing material so as to seal the nozzle  12 . 
     The thermal decomposition unit  4  includes a link  41 , the columnar support  42 , and a lever  43 . The link  41  is a heat-sensitive element that operates in response to the heat of a fire. The link  41  is formed by bonding two thin metal plates  44  into one with a low melting point alloy. The low melting point alloy has a melting point in the range of 60° C. to 200° C. In general, a low melting point alloy having a melting point of 72° C. or 96° C. is used. 
     Each of the two substantially rectangular metal plates  44  has a hole  45  at one end and a U-shaped notch  46  at the other end. The two metal plates  44  are bonded with a low melting point alloy such that the ends having the notches  46  are overlapped with each other. At this time, the notch  46  of one of the metal plates  44  is overlapped over the position of the hole  45  of the other metal plate  44 . After the metal plates  44  are bonded, the columnar support  42  is inserted into one of the holes  45  of the link  41 , and the lever  43  is inserted into the other hole  45 . 
     The columnar support  42  has a strip shape. One end of the columnar support  42  is engaged with the disk  32  of the valve  3  mounted at the outlet of the nozzle  12 , and the other end is engaged with the tip of the lever  43 . As described above, the hole  45  of the link  41  has the columnar support  42  inserted thereinto. A protrusion  47  is provided in the middle of the columnar support  42 , and the link  41  is locked in a groove  47 A provided in the vicinity of the protrusion  47 . 
     The lever  43  is formed by bending an elongated plate into a substantially L-shape. As described above, one end of the lever  43  is inserted into the hole  45  of the link  41 . The other end of the lever  43  is engaged with the columnar support  42 , and the lever  43  is provided with a groove  48  with which the tip of the columnar support  42  is engaged. 
     A concave portion  49  is provided on a surface on the back side of the surface having the groove  48  provided thereon. The concave portion  49  is provided at a position closer to the other end of the lever  43  than the groove  48 . The impress screw  16  is in contact with the concave portion  49 . If the tip of the impress screw  16  presses the concave portion  49  of the lever  43 , a rotating force around the groove  48  serving as a fulcrum and having the columnar support  42  locked therein acts on the lever  43 . However, the hole  45  of the link  41  has one end of the lever  43  inserted thereinto and, thus, the rotation of the lever  43  is prevented. As a result, the link  41 , the columnar support  42 , and the lever  43  that constitute the thermal decomposition unit  4  maintain the engaged state. In addition, the impress screw  16  keeps pressing the valve  3  toward the nozzle  12  via the thermal decomposition unit  4 . 
     If a fire occurs and the low melting point alloy of the link  41  melts, one of the metal plates  44  is peeled off from the other metal plate  44  by the above-described rotation of the lever  43 . As a result, the engaged state of the thermal decomposition unit  4  is released and, thus, the link  41 , the columnar support  42 , and the lever  43  are disengaged. In addition, the valve  3  supported by the columnar support  42  is separated from the nozzle  12  and drops off, and the nozzle  12  is opened. 
     The embodiment of the present invention has been described above. Structures and operations other than those of the embodiment are described below. 
     While the above embodiment has been described with reference to the concave portion  49  as the shape of the portion of the lever  43  that engages with the impress screw  16 , the present invention is not limited thereto. For example, the shape may be a protruding shape. In this case, the shape of the tip of the impress screw  16  can be changed to a concave portion or a groove that matches the protruding shape. 
     In addition, the present invention is also applicable to a sprinkler head using a glass bulb for the thermal decomposition unit  4 . In this case, the shape of the tip of the impress screw  16  may be a concave shape so as to receive the glass bulb. 
     The ratio of (the diameter D 1  of the boss):(the inscribed circle D 2  that the end of each of the slits  21  adjacent to the boss  15  is in contact with):(the outer diameter D 3  of the deflector) is approximately set so that D 1 :D 2 :D 3 =1:2:3. In this way, both the amount of water sprayed on the floor surface and the wall wetting height can be made satisfactory. 
     REFERENCE SIGNS LIST 
     S 1  sprinkler head 
       1  main body 
       2  deflector 
       3  valve 
       4  thermal decomposition unit 
       12  nozzle 
       14  arm 
       15  boss 
       15 A outer peripheral end of boss 
       16  impress screw 
       16 B slope surface 
       21  slit 
       22  slit (first slit) 
       31  valve cap 
       32  disk 
       33  disc spring 
       41  link 
       42  columnar support 
       43  lever