Concealed sprinkler activation

#The invention relates generally to a fire suppression systems and, more particularly, to a concealed fire suppression sprinkler having a more efficient activation.

#Fire suppression systems typically include sprinklers positioned strategically within an area where fire protection is desired. The sprinklers remain inactive most of the time. Even though the sprinklers are inactive, many systems include fire suppression fluid within the conduits that supply the sprinklers. The fluid is pressurized and it is necessary to maintain an adequate seal to prevent any leaks at the sprinklers while they are inactive.

#In some instances, the sprinklers in a fire suppression system may be concealed. Concealed sprinklers are usually covered by a cover plate which is substantially flush with a ceiling in which the sprinkler is mounted. The cover plate is soldered in place such that in the presence of a fire, heat and combustion gasses flow through a small gap between the cover plate and the ceiling. The high temperature melts the solder causing the cover plate to separate from the sprinkler and expose the activator bulb. Because the activator bulb is initially concealed by the cover plate, the flow of combustion gasses to the activator bulb is restricted until the cover plate is removed, thereby delaying the activation of the sprinkler.

#The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

#FIG. 1 is a cross-section of an exemplary portion of a fire suppression sprinkler assembly;

#FIG. 2 is a cross-section of a fire suppression sprinkler assembly according to an embodiment of the invention;

#Referring now to FIG. 1, a portion of a fire suppression sprinkler assembly 10 is illustrated. The fire suppression sprinkler assembly 10 includes a fire suppression sprinkler 20 configured to discharge a mist of fire suppression fluid, such as water for example. The sprinkler 20 includes a housing 22 that establishes a flow path 24 through at least a portion of the housing 22. For example, the sprinkler housing 22 may include a plurality of channels 26 extending from the center of the sprinkler 20 outwards, such that the fire suppression fluid will be discharged through these channels 26 to outside the sprinkler 20. Disposed within the center of the sprinkler 20 is a water seat 30 movable between an inactive and an active position. When the water seat 30, and therefore the sprinkler 20, is in an inactive state, the water seat 30 is configured to close off the flow path 24. An activator bulb or other heat responsive element 40, disposed vertically between the water seat 30 and an adjustment member 42 located at a first end 21 of the sprinkler 20, retains the water seat 30 in an inactive position. The activator bulb 40 operates in a known manner for maintaining the sprinkler 20 in an inactive condition under most circumstances. When experiencing an elevated temperature, such as in the presence of a fire for example, a fluid within the activator bulb 40 expands, causing the bulb to break, and thereby allowing the sprinkler 20 to transition to an active, operating state in a known manner. The fire suppression sprinkler assembly 10 may include other types of fire suppression sprinklers, for example sprinklers 20 having an activator bulb 40 in a horizontal configuration. An exemplary horizontal activator bulb 40 is illustrated in FIG. 2. Though the illustrated sprinkler 20 is a compressive activator bulb 40, alternate configurations, such as a tensile activator bulb for example, are within the scope of the invention. Fire suppression sprinklers 20 having an activator bulb 40 arranged in a horizontal configuration function in substantially the same manner as the fire suppression sprinklers 20 having a vertically oriented activator bulb 40 as described above.

#The fire suppression sprinkler 20 may be mounted to a portion of a building, ship, or other structure, such as to a ceiling for example. Referring now to FIGS. 2 through 7, exemplary fire suppression sprinkler assemblies 10 also include a cover plate 100 mounted adjacent the first end 21 of a sprinkler 20. A top surface 102 of the cover plate 100 connects to an adjacent mounting surface 80 using fasteners, adhesive, or other known connection means. The mounting surface 80 may be a ceiling, or alternatively, may be a portion of a trim can for example. The cover plate 100 is generally concave, such that the first end 21 of the sprinkler 20, including the activator bulb 40, is disposed within a cavity 104 of the cover plate 100 below the plane of mounting surface 80. In one embodiment, the cover plate 100 includes at least one arm 106 for supporting an end of the activator bulb 40. As illustrated in FIG. 4, the cover plate 100 may include a first arm 106a configured to support a first end 44 of the activator bulb 40 and a second arm 106b configured to engage the second opposite end 46 of the bulb 40. A separate cover layer 120 may be disposed about the exterior of the cover plate 100 (FIGS. 3 and 10). In one embodiment, the cover layer 120 is made from a lightweight metallic material, such as a foil for example. The exterior surface of either the cover plate 100 or the cover layer 120 may be painted the same color as the mounting surface 80 so that the fire suppression sprinkler assembly 10 is integrally formed with its surroundings in an aesthetically pleasing manner such that no apparent shadow line exists.

#The cover plate 100 may be manufactured from plastic or another durable material. In one non-limiting embodiment, the cover plate 100 is formed from a thermally and/or visually semi-transparent material. The cover plate 100 includes a plurality of openings 108 that allow heat to transfer into the cavity 104 toward the activator bulb 40 or allow a fire suppression fluid to be discharged outside of the cavity 104. For example, holes or slots 108 may cover in the range of about 25 percent to about 75 percent of the surface area of the cover plate 100. In one embodiment, the plurality of openings 108 may be arranged generally perpendicular to the airflow adjacent surface 80, to increase the activation time of the sprinkler 20. The cover plate 100 may additionally include a plurality of heat features 110 configured to channel heat towards the activator bulb 40 positioned at the center of the cavity 104. The heat features 110, such as ribs for example, protrude inwardly or outwardly from a surface of the cover plate 100 and may have a substantially constant thickness or a variable thickness along the length of each heat feature 110. The plurality of heat features 110 may be identical or may be dissimilar. As illustrated in FIG. 5, the heat features 110 may curve generally radially outwardly from the center of the cover plate 100 or alternatively may be straight.