Fire fighting nozzle and method including pressure...

Fire extinguishers – Processes – With mixing of extinguishing compounds

Reexamination Certificate

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C169S014000, C239S408000, C239S413000, C239S416400, C239S417500, C239S453000, C239S424000, C239S514000, C239S579000, C239S416000

Reexamination Certificate

active

06749027

ABSTRACT:

FIELD OF INVENTION
The invention relates to fire fighting and fire preventing nozzles and more particularly to nozzles for extinguishing or preventing large industrial grade fires including flammable liquid fires and/or for nozzles for vapor suppression, and includes improvements in pressure regulating, educting and chemical discharge features, as well as methods of use.
BACKGROUND OF INVENTION
Prior patents relevant to the instant invention include: (1) U.S. Pat. No. 4,640,461 (Williams) directed to a self educting foam fog nozzle; (2) U.S. Pat. No. 5,779,159 (Williams) directed to a peripheral channeling additive fluid nozzle; and (3) U.S. Pat. Nos. 5,275,243; 5,167,285 and 5,312,041 (Williams) directed to a chemical and fluid or duel fluid ejecting nozzle. Also relevant is the prior art of automatic nozzles, including (4) U.S. Pat. Nos. 5,312,048; 3,684,192 and 3,863,844 to McMilian/Task Force Tips and U.S. Pat. Nos. Re 29,717 and 3,893,624 to Thompson/Efkhart Brass. Also of note are U.S. Pat. No. 5,678,766 to Peck and PCT Publication WO 97/38757 to Baker.
Maintaining a constant discharge pressure from a nozzle tends to yield a constant range and “authority” for the discharge while allowing the nozzle flow rate to absorb variations in head pressure. In certain applications, such as vapor suppression, a fire fighting nozzle is useful if it self regulates to discharge at an approximately constant or targeted pressure. The discharge pressure tends to govern what is referred to as the “authority” of the discharge stream and to a certain extent the stream's range, and it can affect the delivery of an appropriate vapor-suppressing fog.
One application in which a self-regulating nozzle may be useful, thus, is a protection system that includes nozzles permanently stationed around locales that could be subject to the leakage of toxic chemicals. Upon leakage such a permanently stationed configuration of nozzles, probably under remote control, would be optimally activated to provide a predesigned curtain of water/fog to contain and suppress any toxic vapors. In such circumstances it may be optimal for the nozzles to discharge their fluid with a more or less constant range and authority as opposed to having their discharge structured and regulated for a relatively constant flow rate, as is more common among fire fighting nozzles. Water/fog created with a more or less constant range and authority while operating under the conditions of varying head pressure from a fixed nozzle will tend to more reliably form a curtain in a preselected region, again which may be useful for containing escaping vapors from a fixed locale.
Typically nozzles are structured to deliver pre-set gallon per minute flow rate assuming a nominal head pressure such as 100 psi at the nozzle. As the head pressure actually available to the nozzle in an emergency varies, flow rate remains more consistent with such design than does discharge pressure. Structuring a nozzle to alternately target and regulate its discharge pressure will let flow rate vary more with variations in delivered pressure, but may be an optimal design for certain circumstances.
The present invention, in one important aspect, discloses an improved pressure regulating nozzle designed within its operating limits to effectively discharge a fire extinguishing fluid at a pre-selected or targeted discharge pressure. According to current practice this targeted discharge pressure would likely be approximately 100 psi. It is to be understood, however, that the preselected targeted pressure could be easily varied, and a target pressure might more optimally be selected to be 120 psi. The instant inventive design improves the efficiency of achieving such a target pressure as well as offers a design that more easily combines with self-educting features for foam concentrates and with the capacity to throw fluid chemicals, such as dry powder, from the nozzle.
In another important aspect the present invention teaches enhanced eductive techniques, for peripheral and central channeling, which enhanced eduction can be particularly helpful in automatic nozzles or when also throwing chemical such as dry powder.
A typical automatic nozzle designed in accordance with the present invention would be designed to operate over a range of flow rates, such as from 500 gallons per minute to 2000 gallons per minute, at a targeted discharge pressure, such as 100 psi. To target a discharge pressure, or to self regulate pressure, the nozzle design incorporates a self-adjusting baffle proximate the nozzle discharge. In general, when fluid pressure at the baffle, sensed more or less directly or indirectly, is deemed to lie below target, the baffle is structured in combination with the nozzle to “squeeze down” on the effective size of the discharge port for the nozzle. When pressure build-up at the baffle, as sensed directly or indirectly, is deemed to reach or exceed a targeted pressure, the baffle is structured to cease squeezing down and, if necessary, to shift to enlarge the effective size of the annular discharge port. Such enlargement would continue, in general, until the discharge pressure reduces to the preset target or a limit is reached. Such adjustments in the size of the discharge port cause the flow rate to vary, but the fluid that is discharged tends to be discharged with a more constant “authority” and range, an authority and range associated with the targeted pressure. The instant design is structured to improve the efficiency and reliability of settling upon or around a target pressure.
The instant invention achieves a pressure regulating system by providing a design with an adjustable baffle having what is referred to herein as forward and opposing or reverse fluid pressure surfaces. Pressure from fluid applied to opposing sides of the baffle causes the baffle to respond, at least to an extent, as a double acting piston, although perhaps in a complex manner. The so called forward and reverse directions are referenced to the nozzle axial direction with forward being in the direction of fluid discharge. The forward and reverse pressure surface areas provided by the baffle preferably are not equal. In preferred embodiments the effective pressure surface area of the reverse side exceeds the effective pressure surface area of the forward side. Thus, were the pressure on both surfaces equal, the baffle would automatically gravitate to its most closed position, minimizing or closing the discharge port.
The effective forward pressure surface area will likely, in fact, vary with pressure and with flow rate. Limited experience indicates that the forward fluid pressure surface area also varies with bafflehead design and nozzle size. Further, in preferred embodiments, although pressure from the primary fire fighting fluid, directly or indirectly, is applied to both forward and opposing fluid pressure surfaces, the value of the reverse pressure is usually less than, although a function of, the pressure on the forward surface.
A relief valve is preferably provided, such that at or slightly past a targeted pressure the valve can begin to relieve the effective pressure on (at least) one side of the baffle. At least one relief value promises to enhance responsiveness. In preferred embodiments the one side of the baffle upon which pressure is relieved would be the reverse side, the side opposing the forward pressure of the primary fluid on the bafflehead. Specifically, in such an embodiment, when the pressure of the primary fire extinguishing fluid proximate the nozzle discharge causes the pressure sensed by whatever means by the relief valve to exceed a pre-selected value, reverse pressure is relieved on the interior baffle chamber surfaces and the baffle tends to forwardly adjust in response to forward fluid pressure. Alternately, the baffle might simply stabilize at a balanced pressure position in preferred embodiments, with or without the (or a) relief valve slightly bleeding. That is, a nozzle could be designed to achieve a balanced pressure baffle position with or without a r

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