Patent Application
20070246231
1. Field of the Invention
The present invention relates to an automatic fire protection sprinkler, and in particular an extended coverage, horizontal sidewall sprinkler for light hazard occupancies.
2. Related Art
Fire protection sprinklers conventionally are connected to a conduit to receive pressurized fire-extinguishing fluid, such as water. A typical sprinkler has a base with a threaded portion for connection to the conduit and an output orifice to output the fluid to provide fire control and/or suppression. The output orifice is sealed by a seal cap, which is held in place by a release mechanism. The release mechanism is designed to release the cap under predetermined conditions, thereby initiating the flow of fire-extinguishing fluid. A typical release mechanism includes a thermally-responsive element, e.g., a frangible bulb or fusible link, and may also include a latching mechanism.
Certain conventional sprinklers have a pair of arms that extend from the base portion and meet at a hub portion to form a frame. The hub portion is spaced apart from the output orifice of the base portion and is aligned with a longitudinal axis thereof. The hub portion may have a set-screw configured to apply a pre-tension force to the release mechanism. A deflector may be mounted on the hub, transverse to the output orifice, to provide dispersion of the output fluid.
Fire protection sprinklers may be mounted on a fluid conduit running along a ceiling and may either depend downward from the conduit, which is referred to as a “pendent” configuration, or may extend upward, which is referred to as an “upright” configuration. Alternatively, a sprinkler may be mounted on a wall, a certain distance below the ceiling, which is referred to as a “horizontal sidewall” configuration. Horizontal sidewall sprinklers have an output orifice that is oriented so that the fluid is output horizontally and sprays onto an area to be protected in front and to the sides of the sprinkler. Such sprinklers may be mounted in a supporting cup with an escutcheon and cover, to provide a concealed configuration.
NFPA 13 (“Standard for the Installation of Sprinkler Systems,” National Fire Protection Association, Inc., 2002 Edition) classifies automatic sprinklers according to “occupancies,” which define requirements for sprinkler design, installation, and water supply requirements. Light hazard occupancies are defined as areas in which the quantity and/or combustibility of contents is low, and fires with relatively low rates of heat release are expected (NFPA 13, Section 5.2).
As described in Section 5.9 of UL 199 (“Standard for Automatic Sprinklers for Fire-Protection Service,” Underwriters' Laboratories, 11th Ed., Nov. 4, 2005), an “extended coverage” sprinkler for light hazard occupancies is a sprinkler intended: a) for use at greater than standard spacing; b) to open automatically by operation of a heat responsive element and releasing mechanism having a response time equal to or less than a standard response sprinkler used on standard spacings; c) to discharge water over a specified coverage area at a specified minimum water flow rate; and d) for use in light hazard occupancies as described in NFPA 13.
According to Section 8.9 of NFPA 13, extended coverage sidewall sprinklers for light hazard occupancies may have a spacing of up to 28 ft between sprinklers, as measured along the wall on which the sprinklers are mounted, and may cover an area of up to 400 ft2.
In one aspect, the present invention provides a sidewall fire protection sprinkler, including a deflector having a central portion curved about a transverse axis from an output direction of the sprinkler; end portions extending along the transverse axis outwardly from the central portion, the end portions having an upper part and a lower part separated by a gap; and planar portions extending in the output direction from a top edge of the end portions.
Embodiments of the present invention may include one or more of the following features.
The planar portions may be angled downward with respect to the transverse axis. The planar portions may be angled downward with respect to the output direction. A width of the planar portions along the transverse axis may be substantially less than a width of the end portions along the transverse axis. The planar portions may extend farther in the output direction than any other portion of the deflector.
The end portions may be curved about the transverse axis with a radius increasing in a direction away from the central portion. The lower parts of the end portions have a slot that is angled with respect to the transverse axis.
The nominal K-factor of the sprinkler may be 5.6. For a coverage area of 28 ft along a wall by 10 ft forward throw, the sprinkler may require a system pressure of less than about 25 psi and flow rate of less than about 28 gpm. For a coverage area of 28 ft along a wall by 8 ft forward throw, the sprinkler may require a system pressure of less than about 17 psi and flow rate of less than about 23 gpm.
These and other objects, features and advantages will be apparent from the following description of the preferred embodiments of the present invention.
The present invention will be more readily understood from a detailed description of the preferred embodiments taken in conjunction with the following figures.
Two frame arms 130 extend from the body 105 in a vertical plane perpendicular to the wall and meet at a hub 135 (see
A release mechanism having a thermally-responsive element, e.g., a frangible bulb 140, is positioned between the hub 135 and the seal cap 120 to hold the seal cap 120 in place over the output orifice 115. As shown in the sectional view of
The deflector 200 has a central portion 210 that is curved toward the body 105 of the sprinkler 100 about the transverse axis 205. The central portion 210 has a raised portion 215 with a radius of between about 0.5 inches and about 2.5 inches, preferably about 0.8 inches, in a vertical plane at the center of the deflector 200, orthogonal to the transverse axis 205 (see
The end portions 225 of the deflector extend outwardly from the central portion 210 along the transverse axis 205. The radius of the end portions 225 increases linearly in the transverse direction away from the center of the deflector 200, resulting in the end portions 225 having a generally conical shape. The end portions 225 are divided into an upper 230 and lower part 235 with a gap 240 between these parts. The lower parts 235 have a vertical end edge with a slot 245 that is angled with respect to the transverse direction, as shown, for example, in
The planar portions 250 extend in the output direction from the top edges of the end portions 225 and are generally rectangular, with the longer dimension extending in the output direction. For example, the length of the planar portion may be about 0.7 inches. The width of the planar portion 250 measured in the transverse direction is, e.g., about 0.25 inches (about 0.3 inches measured along the surface of the planar portion), which is substantially less than the width of the end portions 225 in the transverse direction, e.g., about 0.7 inches. The planar portions are angled downward in both the output direction and the transverse direction. For example, the planar portions 250 may be angled downward by, e.g., about 17° (±about 10%) in the output direction and, e.g., about 13° (±about 10%) in the transverse direction. The planar portions 250 extend farther in the output direction than any other portion of the deflector (see
The planar portions help project fluid to the sides in a diagonal direction toward the corners of the spray pattern, thereby forming a wide rectangular pattern, while maintaining the desired density throughout the spray pattern. For example, the sprinkler may be used as an extended coverage sidewall sprinkler at a wall spacing of 28 ft and a forward throw of about 10 ft. In an alternative embodiment, the sprinkler may have a forward throw of about 8 ft. Such patterns are particularly useful in long, relatively narrow spaces, such as hallways or decks (e.g., a loading dock deck with an overhanging roof).
As mentioned above, the K-factor of the sprinkler is 5.6, which provides a significant decrease in system flow and pressure requirements with respect to higher K-factor sprinklers in hallway and deck applications. For example, for a coverage area of 28 ft wide by 10 ft (forward throw in the output direction), the sprinkler of the present invention requires a pressure of less than about 25 psi and flow rate of less than about 28 gpm. For a coverage area of 28 ft wide by 8 ft, the sprinkler requires a pressure of less than about 17 psi and flow rate of less than about 23 gpm. By contrast, a sidewall sprinkler with a K-factor of 8.0 and a coverage area of 28 ft wide by 14 ft may require a pressure of 25 psi and a flow rate of 40 gpm.
While the present invention has been described with respect to what is presently considered to be the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
