Fire extinguishers – Sprinkler heads
Reexamination Certificate
2000-05-23
2001-08-21
Scherbel, David A. (Department: 3752)
Fire extinguishers
Sprinkler heads
C169S041000, C169S057000, C239S498000, C239S504000, C239S524000
Reexamination Certificate
active
06276460
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to residential sprinkler arrangements and, more particularly, to fast response residential sprinkler arrangements.
The National Fire Protection Association standards NFPA 13D and 13R for residential sprinklers specify minimum flow rates of 9 gallons per minute at a pressure of 9 psi for single sprinklers having a maximum spacing of 6 feet from a wall and 10 gallons per minute at a pressure of 11.1 psi for single sprinklers having a maximum distance of 7 feet or 8 feet from a wall. For two or more sprinklers in the same room having 12, 14 or 16 foot spacings, the minimum required flow rate is 8 gallons per minute at a pressure of 7.1 psi. In order to provide the necessary protection, the distribution of water along the adjacent walls and over the floor area beneath the sprinklers should be substantially uniform.
Various sprinkler arrangements and deflector designs have been proposed heretofore to provide desired water flow rate distribution patterns. For example, the Bosio et al. U.S. Pat. No. 5,687,914 discloses a sprinkler arrangement having a deflector supported from a pair of frame arms which has enlarged tines in the plane of the frame arms with their inner ends bent away from the frame arms and their outer ends inclined slightly toward the frame arms. The Grinnell Model F680 sprinkler has a planar deflector with keyhole-shaped slots distributed around the periphery with the circular part of the keyhole for slots in the plane of the frame arms having a diameter smaller than that of the other slots. Those arrangements, however, do not provide the desired water distribution uniformity for flow rates and pressures of the type mentioned above for residential sprinklers. The Pahila U.S. Pat. No. 6,026,907 discloses one form of residential sprinkler intended to satisfy the water distribution and uniformity requirements.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a residential sprinkler arrangement which overcomes disadvantages of the prior art.
Another object of the invention is to provide a fast response residential sprinkler arrangement providing highly uniform water distribution at the minimum required flow rates and pressures.
These and other objects of the invention are attained by providing a sprinkler having a sprinkler body with a passage having an orifice which is normally closed by a cap retained in position by a thermally responsive element and a deflector spaced from the orifice and supported from the sprinkler body by a pair of arms and disposed generally in a plane perpendicular to the axis of the passage in which the deflector has a central portion and a peripheral portion with a circumferential array of tines separated by slot-like openings including slot-like openings located in the plane of the frame arms which are substantially longer than the other slot-like openings and preferably have a width in a range from about 25% to about 75%, desirably about 35% to about 65%, of the thickness of the adjacent part of the frame arms and a root diameter in the range from about 150% to about 300%, desirably about 190% to about 260%, of the thickness of the adjacent part of the frame.
Preferably the tines adjacent to the slot-like openings located in the plane of the frame arms have an outer portion which is displaced out of the plane of the deflector in the direction away from the body of the sprinkler with the outer end inclined slightly toward the sprinkler body. In a preferred embodiment, the sprinkler has a K factor in the range from about 3 to 6, and desirably about 4, and the portions of the deflector on opposite sides of the plane of the frame arms each have seven slot-like openings formed between adjacent tines with two openings disposed at about 45° to the plane of the frame arms on each side extending inwardly from the periphery of the deflector to a lesser extent than the other slot-like openings while the other five slot-like openings on each side of the plane of the frame arms have a length intermediate that of the openings in the plane of the frame arms and that of the openings at about 45° to that plane. In order to provide a fast response, the sprinkler preferably has a thermally responsive device in the form of a glass bulb which normally retains the cap in position in the orifice and is designed to release the cap at a relatively low temperature such as about 155° F.
REFERENCES:
patent: 2135138 (1938-11-01), Kendall
patent: 4091873 (1978-05-01), Werner
patent: 5366022 (1994-11-01), Meyer et al.
patent: 5609211 (1997-03-01), Meyer et al.
patent: 5687914 (1997-11-01), Bosio et al.
patent: 5839667 (1998-11-01), Fishcer
patent: 5865256 (1999-02-01), Pounder
patent: 6026907 (2000-02-01), Pahila
BakerBotts LLP
Ganey Steven J.
Reliable Automatic Sprinkler Co., Inc.
Scherbel David A.
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