Patent Description:
Early suppression fast response (ESFR) fire suppression sprinklers face challenges when used to protect commodities in warehouses having a large clearance between the warehouse ceiling and the commodity. Warehouses having a ceiling height of <NUM> (<NUM> feet) and greater may have commodities shelved at a height of <NUM> (<NUM> feet) and less from the floor, leaving a clearance of <NUM> (twenty feet) or greater between the ceiling (near where the sprinklers are positioned) and the commodity. The challenges to ESFR sprinklers operating at such clearances include maintaining a core flow of fire suppressing liquid which has sufficient density and velocity to suppress a fire below the sprinkler itself while also maintaining an outer surrounding "umbrella" spray pattern to provide the required disbursement protecting the desired area, as well as sufficient flow in an intermediate range between the outer umbrella pattern and the core flow to prevent a fire in that intermediate zone from growing and overwhelming the outer umbrella. However, for some prior art ESFR sprinkler designs the large clearance distance between the sprinkler and the commodity allows the spray pattern to become disbursed over too large an area, thereby reducing the spray pattern density, especially in the intermediate zone, and hence the sprinkler's fire suppression effectiveness. Such conditions may also allow updrafts created by a fire plume in the intermediate zone to disrupt and lift the outer umbrella spray pattern, which in some cases causes wetting and cooling of adjacent sprinklers, thereby preventing or delaying their operation. This phenomenon is known as "skipping" because the fire's heat plume "skips" the nearby cooled sprinklers which are otherwise best placed to suppress the fire. Furthermore, skipping also tends to trigger sprinklers that are more remote from the fire, and thus less effective at fire suppression. The result is an increase in both fire and water damage as well as additional risk to firefighters called to fight the blaze.

There is clearly an opportunity to improve fire suppression sprinklers, particularly ESFR type sprinklers, to handle the challenges of high clearance warehouse fire protection.

Sprinkler assemblies according to the prior art can for example be found in <CIT>, <CIT>, <CIT> or <CIT>. Another sprinkler deflector is shown in <CIT>.

The invention concerns a deflector for a fire suppression sprinkler according to claim <NUM>.

The invention encompasses a deflector for a fire suppression sprinkler. According to the invention, the deflector comprises a circular plate having a periphery surrounding a center. First and second slots in the plate extend from diametrically opposed points on the periphery along a common diameter toward the center. A first plurality of slots are positioned around the plate between the first and second slots. Each of the slots of the first plurality extends from the periphery along a respective chord of the circular plate which chord does not pass through the center.

A second plurality of slots are positioned around the plate. Each slot of the second plurality of slots is positioned between the first and second slots and extends from the periphery along a respective radius of the circular plate toward the center.

Further the first and second slots have respective ends at a first distance from the center. A first half of the first plurality of slots have respective ends at a second distance from the center. A second half of the first plurality of slots have respective ends at a third distance from the center. The second plurality of slots have respective ends at a fourth distance from the center. The first distance is less than the second distance, the second distance is less than the third distance, and the third distance is less than the fourth distance.

In a preferred embodiment, the first and second slots define respective first and second areas. The first and the second areas each are greater than any area defined by any slot of the first and second plurality of slots in an example embodiment. In an other preferred embodiment, first and second regions of the periphery respectively flanking the first and second slots each have a radius less than a radius of a remainder of the periphery.

Preferably, each one of the slots of the first plurality of slots is asymmetrical with respect to the respective chord of the circular plate along which each one of the slots of the first plurality extends. Preferably, each one of the slots of the second plurality of slots is symmetrical with respect to the respective radius of the circular plate along which each one of the slots of the second plurality extends.

In another preferred embodiment, each one of the first and second slots has a first width over a first region proximate to the periphery and a second width over a second region positioned between the first region and the center. The first width is less than the second width in this another preferred embodiment.

<FIG> and <FIG> show an example fire suppression sprinkler <NUM>. Sprinkler <NUM> may be, for example, an early suppression fast response (ESFR) sprinkler having a "k factorEN <NUM>-<NUM>" from about <NUM> to about <NUM> and specifically <NUM> ("k factorUS" from about <NUM> to about <NUM>, and specifically <NUM>). The k factor relates the water discharge rate "Q" from the sprinkler to the water pressure "p" within the sprinkler by the formula Q=k(p)<NUM>/<NUM>.

Sprinkler <NUM> comprises a body <NUM> which surrounds a bore <NUM>. Bore <NUM> defines a flow axis <NUM> arranged coaxially with the bore. Body <NUM> may have a threaded nipple <NUM> for connection of the sprinkler <NUM> to a piping network of a fire suppression system (not shown) and a plurality of flat surfaces <NUM> which receive a wrench for applying torque to the sprinkler during installation. First and second arms <NUM> and <NUM> extend along flow axis <NUM> from opposite sides of body <NUM> and support a nose <NUM> mounted on the ends of the arms. Nose <NUM> is positioned coaxially with the flow axis <NUM> and supports a heat sensitive trigger <NUM>. Nose <NUM> has a portion <NUM>, advantageously cylindrical, which extends beyond the ends of arms <NUM> and <NUM> a distance <NUM>, thereby permitting a deflector to be mounted on nose <NUM> in spaced relation to the ends of arms <NUM> and <NUM>.

In this example the heat sensitive trigger <NUM> comprises a frangible glass bulb <NUM> containing a heat sensitive liquid <NUM>. Bulb <NUM> extends between nose <NUM> and a sealing member <NUM>, in this example a plug <NUM> which overlies and seals the bore <NUM> through engagement with body <NUM>. Nose <NUM> also comprises a set screw <NUM>, threaded within a bore <NUM> in nose <NUM> aligned with the bulb <NUM>. The set screw <NUM> permits assembly of the bulb <NUM> into the sprinkler <NUM> and adjustment of the compression force on the bulb. Bulb <NUM> supports the plug <NUM> to maintain the sprinkler <NUM> in its closed configuration (shown). Bulb <NUM> breaks when the ambient temperature reaches a predetermined value, for example, indicative of a fire. When the bulb breaks it no longer support plug <NUM> which is released from engagement with the body <NUM> to open sprinkler <NUM> and allow water or other fire suppressing fluid to be discharged. Other heat sensitive triggers are also feasible, such as those having components held together by a solder which melts at a predetermined temperature to allow the sprinkler to open.

A deflector <NUM> is mounted on the nose <NUM>. As shown in <FIG> and <FIG>, the example deflector <NUM> comprises a substantially circular plate <NUM> oriented transversely to the flow axis <NUM>, and having a thickness <NUM>. The deflector <NUM> is positioned in spaced relation to the ends of arms <NUM> and <NUM> at the distance <NUM>. In an example embodiment, the distance <NUM> is greater than twice the thickness <NUM> of deflector <NUM>. In a preferred embodiment, the distance <NUM> is approximately three times the thickness <NUM> of deflector <NUM>.

A plurality of slots <NUM> in plate <NUM> define a plurality of tines <NUM>. Slots <NUM> and tines <NUM> are designed in conjunction with nose <NUM>, arms <NUM> and <NUM> and bore <NUM> to meet standards governing discharge rate, coverage area size and shape, and other performance standards in order to be permitted to be installed under the codes and standards established by authorities such as the National Fire Protection Association (NFPA), including NFPA <NUM> "Standard for the Installation of Sprinkler Systems". The required testing that compliant sprinklers must pass is set forth in standards promulgated by nationally recognized testing laboratories such as FM Global and UL, such standards including UL <NUM> and FM <NUM>. These standards set forth various tests that compliant sprinklers must pass, including water flow and distribution tests, Actual Delivered Density (ADD) tests, and live fire tests, with UL <NUM> including a fire test specifically focused on the high clearance applications.

The example sprinkler <NUM> is designed to meet the UL <NUM> criteria for an ESFR sprinkler that may be used in warehouses with ceilings <NUM> (<NUM> feet) high and greater and wherein the stored commodity to be protected is shelved <NUM> (<NUM> feet) from the floor of the warehouse and lower, yielding <NUM> (<NUM> feet) of clearance or greater between the ceiling and commodity. To this end, deflector <NUM> comprises first and second slots <NUM> and <NUM> in plate <NUM>. Slots <NUM> and <NUM> are radially oriented with respect to the flow axis <NUM> and, as apparent from <FIG>, are aligned, respectively, with the first and second arms <NUM> and <NUM>. Slots <NUM> and <NUM> extend from the periphery <NUM> of the plate <NUM> to respective points <NUM> and <NUM> which underlie the nose <NUM>. The remainder 46a of the plurality of slots <NUM> extend from periphery <NUM> to respective points in spaced relation away from nose <NUM> as described in detail below.

In the example deflector <NUM> slots <NUM> and <NUM> have first width <NUM> proximate to periphery <NUM> and a second width <NUM> distal to the periphery. The second width <NUM> is greater than the first width <NUM>. As further shown in <FIG> and <FIG>, the arms <NUM> and <NUM> have a first thickness <NUM> proximate to nose <NUM> and a second thickness <NUM> proximate to the body <NUM>. As shown in <FIG> for sprinkler <NUM>, the first widths <NUM> of first and second slots <NUM> and <NUM> is greater than the first thicknesses <NUM> of arms <NUM> and <NUM>, and the second widths <NUM> of the slots <NUM> and <NUM> is greater than the second thicknesses <NUM> of arms <NUM> and <NUM>. Additionally, the first and second slots <NUM> and <NUM> define respective first and second areas <NUM> and <NUM>. Each area <NUM> and <NUM> is greater than any area defined by any slot of the remainder of slots 46a.

As further shown in <FIG>, tines <NUM> and <NUM> which are positioned on opposite sides of the first and second slots <NUM> and <NUM> each have ends at a first distance <NUM> measured from the flow axis <NUM>. Tines <NUM> positioned on opposite sides of the remainder of slots 46a each have ends at a second distance <NUM> that is greater than the first distance <NUM>. In a practical example of a deflector <NUM> the first distance <NUM> ranges from about <NUM> (<NUM> inches) to about <NUM> (<NUM> inches), with a first distance of about <NUM> (<NUM>) expected to be advantageous. The second distance <NUM> ranges from about <NUM> (<NUM> inches) to about <NUM> (<NUM> inches), with a second distance of about <NUM> (<NUM> inches) expected to be advantageous when the first distance is about <NUM> (<NUM> inches) as noted above.

The remainder of slots 46a (i.e., slots other than first and second slots <NUM> and <NUM>) are organized as pairs of slots. A first pair of slots <NUM> flank (i.e. are positioned on opposite sides) of the first slot <NUM> and a second pair of slots <NUM> flank the second slot <NUM>. Slots <NUM> and <NUM> extend along respective lines <NUM> and <NUM> which do not pass through the flow axis <NUM>. The slots <NUM> and <NUM> are furthermore asymmetric with respect to respective lines <NUM> and <NUM> as evidenced by the curved perimeter region <NUM> present only on one side of slots <NUM> and <NUM>. A third pair of slots <NUM> also flank the first slot <NUM>, and a fourth pair of slots <NUM> also flank the second slot <NUM>. In the example embodiment of <FIG> the first pair of slots <NUM> is positioned between the first slot <NUM> and the third pair of slots <NUM>, and the second pair of slots <NUM> are positioned between the second slot <NUM> and the fourth pair of slots <NUM>. Slots <NUM> and <NUM> extend along respective lines <NUM>, <NUM> which do not pass through the flow axis <NUM>. The slots <NUM> and <NUM> are furthermore asymmetric with respect to respective lines <NUM> and <NUM> as evidenced by the curved perimeter region <NUM> present only on one side of slots <NUM> and <NUM>.

The remainder of slots 46a further comprises intermediate slots <NUM>. Each intermediate slot <NUM> is positioned between two slots of the plurality of slots <NUM> (the plurality of slots including all slots in plate <NUM>). Intermediate slots <NUM> extend along and are symmetric with respect to respective lines <NUM> which pass through the flow axis <NUM>. Unlike the first and second slots <NUM> and <NUM>, the slots <NUM>, <NUM>, <NUM>, <NUM> and <NUM> which comprise the remainder of slots 46a each extend from the periphery <NUM> of the plate <NUM> to respective points which are in spaced relation to the nose <NUM>. Slots <NUM> and <NUM> comprising the first and second pairs of slots extend to first points <NUM>; slots <NUM> and <NUM> comprising the second pairs of slots extend to second points <NUM> and intermediate slots <NUM> extend to third points <NUM>. Third points <NUM> are farther from the flow axis <NUM> than the second points <NUM>, which are farther from the flow axis <NUM> than the first points <NUM>.

<FIG> illustrates an example deflector <NUM> in isolation from a sprinkler body. In this example deflector <NUM> comprises a circular plate <NUM> having a periphery <NUM> surrounding a center <NUM>. First and second slots <NUM>, <NUM> in plate <NUM> extend from diametrically opposed points on the periphery along a common diameter <NUM> toward the center <NUM>. A first plurality of slots <NUM> are positioned around plate <NUM>. Each slot <NUM> of the first plurality of slots extends from the plate periphery <NUM> along a respective chord <NUM> of the circular plate <NUM>. A second plurality of slots <NUM> are positioned around plate <NUM>. Each slot <NUM> of the second plurality is positioned between the first and second slots <NUM> and <NUM> and extends from the periphery <NUM> along a respective radius <NUM> of the circular plate <NUM> toward the center <NUM>.

As further shown in <FIG>, the first and second slots <NUM> and <NUM> have respective ends <NUM>, <NUM> at a first distance <NUM> from the center <NUM>. A first half 124a of the first plurality of slots <NUM> have respective ends <NUM> at a second distance <NUM> from the center <NUM>, and a second half 124b of the first plurality of slots <NUM> have respective ends <NUM> at a third distance <NUM> from center <NUM>. The second plurality of slots <NUM> have respective ends <NUM> at a fourth distance <NUM> from the center <NUM>. According to the invention, the first distance <NUM> is less than the second distance <NUM>, the second distance is less than the third distance <NUM>, and the third distance is less than the fourth distance <NUM>.

First and second slots <NUM> and <NUM> define first and second areas <NUM>, <NUM>. Each first and second area is greater than any area defined by any slot of the first or second plurality of slots <NUM>, <NUM>. Plate <NUM> further comprises first and second peripheral regions <NUM> and <NUM> which respectively flank the first and second slots <NUM> and <NUM>. Each peripheral region <NUM>, <NUM> has a radius <NUM> less than a radius <NUM> of a remainder <NUM> of periphery <NUM>.

As further depicted in <FIG>, each slot <NUM> of the first plurality of slots is asymmetrical with respect to the respective chord <NUM> along which it extends. The asymmetry is manifest by the curved perimeter regions <NUM> on one side of the slots <NUM>. Slots <NUM> of the second plurality of slots are symmetric with respect to respective radii along which they extend. Additionally, each one of the first and second slots has a first width <NUM> over a first region <NUM> proximate to periphery <NUM> and a second width <NUM> over a second region <NUM> positioned between the first region <NUM> and the center <NUM>. In this example embodiment the first width <NUM> is less than the second width <NUM>.

Claim 1:
A deflector (<NUM>) for a fire suppression sprinkler, said deflector (<NUM>) comprising:
a circular plate (<NUM>) having a periphery (<NUM>) surrounding a center (<NUM>);
first and second slots (<NUM>, <NUM>) in said plate (<NUM>) extending from diametrically opposed points on said periphery (<NUM>) along a common diameter (<NUM>) toward said center (<NUM>);
a first plurality of slots (<NUM>) positioned around said plate (<NUM>) between said first and second slots (<NUM>, <NUM>), each of said slots (<NUM>) of said first plurality extending from said periphery (<NUM>) along a respective chord (<NUM>) of said circular plate (<NUM>) which chord (<NUM>) does not pass through said center (<NUM>); and
a second plurality of slots (<NUM>) positioned around said plate (<NUM>), each slot (<NUM>) of said second plurality of slots (<NUM>) being positioned between said first and second slots (<NUM>, <NUM>) and extending from said periphery (<NUM>) along a respective radius (<NUM>) of said circular plate (<NUM>) toward said center, wherein said first and second slots (<NUM>, <NUM>) have respective ends (<NUM>, <NUM>) at a first distance (<NUM>) from said center (<NUM>);
a first half (124a) of said first plurality of slots (<NUM>) have respective ends (<NUM>) at a second distance (<NUM>) from said center (<NUM>);
a second half (124b) of said first plurality of slots (<NUM>) have respective ends (<NUM>) at a third distance (<NUM>) from said center (<NUM>);
said second plurality of slots (<NUM>) have respective ends (<NUM>) at a fourth distance (<NUM>) from said center (<NUM>); wherein
said first distance (<NUM>) is less than said second distance (<NUM>), said second distance (<NUM>) is less than said third distance (<NUM>), and said third distance (<NUM>) is less than said fourth distance (<NUM>).