Note: Descriptions are shown in the official language in which they were submitted.
CA 02423593 2003-10-08
IMPROVED FIRE FIGHTING NOZZLE AND METHOD
INCLUDING PRESSURE REGULATION,
CHEMICAL AND EDUCTION FEATURES
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. Patent No.
4,640 461 (Williams) directed to a self educting foam fog nozzle; (2) U.S.
Patent No.
5,779, 159 (Williams) directed to a peripheral channeling additive fluid
nozzle; and
(3) U.S. Patent 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. Patent Nos. 5,312,048; 3,684,192 and
3,863,844
to McMilian/Task Force Tips and U.S. Patent Nos. Re 29,717 and 3,893,624 to
Thompson/Elkhart Brass. Also of note are U.S. Patent 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
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range and "authority" for the discharge while allowing the nozzle flow rate to
absorb
variations in head pressure, as it were. In certain applications, such as
vapor suppression,
a fixed fire fighting nozzle is particularly 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. A constant discharge pressure comes closer to a consistent
delivery of a
stream at a fixed range.
One specific application in which a self-regulating nozzle may be useful is in
a
fixed protection system that includes nozzles permanently stationed around
locales
subject to the leakage of toxic chemicals. Upon leakage, a permanently
stationed
configuration of constant pressure nozzles, possibly under remote control,
could be
activated to provide a predesigned curtain of water/fog to contain and
suppress any toxic
vapors. In such circumstances it may be optimal for 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
typical for nozzles.
Water/fog created with approximately constant range and authority, while
operating under
conditions of varying head pressure, will more reliably curtain a preselected
region from
a fixed locale.
Frequently nozzles are structured to deliver a pre-set gallons-per-minute flow
rate,
assuming a nominal head pressure, such as 100 psi at the nozzle. As the head
pressure
actually available to a nozzle in an emergency can vary, flow rate remains
more consistent
in such designs than range. Alternately structuring a nozzle to target and
regulate
discharge pressure lets flow rate vary with variations in delivered pressure
while keeping
range more constant.
The present invention discloses an improved pressure regulating nozzle
designed
to effectively discharge a fire extinguishing fluid at a pre-selected
discharge pressure and
range, up to a targeted flow rate, and thereafter to maintain relatively
constant flow rate
while discharge pressure and range are allowed to increase . A preselected
discharge
pressure, for example, would likely be approximately 100 psi, but the
preselected pressure
could vary, and might more optimally be selected to be approximately 120 psi.
Likewise
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a targeted flow rate is selected. This selection of targeted flow rate need
only be
approximate. The inventive design combines the benefit value of maintaining
range at
low supply pressures while maintaining flow rate at higher supply pressures,
thereby
accommodating minimum range requirements on the one hand while more easily
accommodating self-educting features for foam concentrates and a capacity to
throw fluid
chemicals such as dry powder on the other hand, where possible.
The invention includes enhanced eductive techniques, for both peripheral and
central channeling, which enhanced eduction can be particularly helpful in
automatic
nozzles or when throwing chemicals such as dry powder.
A typical fire fighting nozzle may be designed to be adjusted to operate over
a
range of flows, such as 500 gallons-per-minute to 2000 gallons-per-minute,
given a certain
discharge pressure (typically assumed to be around 100 psi). In an automatic
nozzle, to
select and self regulate for pressure while allowing flow to vary, nozzle
design
incorporates a self-adjusting baffle or the like proximate the nozzle
discharge. In general,
when fluid pressure at such a baffle, sensed directly or indirectly, is deemed
to lie below a
selected pressure, the baffle is structured in combination with the nozzle
body to "squeeze
down" on the effective size of the discharge orifice. When pressure builds up
at the baffle,
sensed directly or indirectly, to reach or exceed a preselected pressure, the
baffle is
structured to cease squeezing down and, if necessary, to shift to enlarge the
effective size
of the nozzle discharge orifice. Enlargement continues, in general, until the
discharge
pressure reduces to the selected value. Adjustments in the size of the
discharge port cause
flow rate to vary but the discharge tends to have constant "authority" and
range.
The instant invention achieves a hybrid pressure regulating and flow
regulating
system. Designs for flow and embodiments of automatic nozzles are themselves
discussed
in detail in the above applications. This invention includes further
improvements in self-
adjusting nozzles. To review the basics of a nozzle, a fire fighting nozzle
defines a
conduit for a fire fighting fluid that terminates in a discharge orifice. The
fire fighting
fluid is usually water, and while it may be treated and discussed as water
herein, it should
be understood that nozzle technology is applicable to
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various fire fighting fluids. The conduit and discharge orifice structure are
typically
designed in combination to recover, to the extent practical, fire fighting
fluid pressure
available from the fluid source. Recovery of pressure affects range.
Given generally anticipatable supply ranges, in pressure and flow, for the
fire
fighting fluid (industry standard sources of pressurized water might be
anticipated to vary
between 75 psi and 150 psi,) nozzle body conduits and discharge orifices may
be designed
to define an effective, or practical, flow window. For instance, a "two and
one-half inch"
nozzle might be adjustable to effectively flow between 150 GPM and 600 GPM
while a
"sixteen inch" nozzle might be adjustable to effectively flow between 4,000
GPM and
16,000 GPM, both being affected by variations in supply pressure or quantity.
An adjustable discharge orifice, automatic or manual, is designed to be
adjusted
within a range of flow effectiveness of a nozzle body. Fluid flow rate through
the nozzle
may vary within a nozzle's effective flow window, again taking into account
variations in
source supply and pressure. Minimum limits on an effective flow window include
a
minimum effective "gap" size, or a minimum effective width of a typically
annular
discharge orifice. Below a certain "gap" size the thickness ofthe wall ofwater
discharged
diminishes such that the water wall tends to disintegrate and nozzle throw
performance
suffers. On the other end, a "gap" can get so large that the fixed conduit
bore structure
itself governs throw. There is thus a practical limit to the flow of water
that can be
efficiently flowed through a nozzle bore.
It is to be understood that although adjustable discharge orifices may be
traditionally designed in terms of an adjustable baffle within a conduit, any
element of a
nozzle structure defining at lest in part the discharge orifice, including an
outer wall
portion, in theory could bean adjustable element. We refer to traditional
designs for
convenience, in regard to an adjustable baffle located in a conduit where the
adjustment
of the baffle forward and backward governs gap size. There is a range in which
such
adjustment is effective. The range is related to an effective or practical
fluid flow window
of the nozzle.
A given conduit and discharge orifice contribute to defining a "k" factor for
a
nozzle. Flow rate and discharge pressure are related by the formula: r=kfp,
where r is
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the flow rate, p the discharge pressure and k the "k" factor. It can be seen
that for a
constant k, flow varies with the square root of pressure. With a fixed conduit
and
discharge orifice, discharge pressure p rises with increased supply pressure
from the fluid
source while flow rate "tends" to remain relatively constant, at least as
compared to
pressure, because it only increases with the square root of pressure.
"Automatic" nozzles have automatically adjustable discharge orifices.
Automatically adjustable discharge orifices are typically designed to maintain
a selected
discharge pressure, such as 100 psi. In such automatic nozzles, there is
typically a means
for sensing discharge fluid pressure and a biasing means structured to adjust
the discharge
orifice (sometimes referred to as the "gap") until the sensed discharge
pressure is
approximately the preselected discharge pressure. (The word "approximately" is
used
herein throughout because automatic nozzle designs are only "approximately"
accurate.)
As a result of sensing and adjustment, a discharge orifice or gap is narrowed
or widened
so that the sensed discharge pressure is approximately the selected discharge
pressure.
When the discharge orifice or gap is narrowed, fluid flow rate through the
nozzle is
reduced. As the gap is widened, fluid flow rate through the nozzle is
increased. As
discussed above, however, if the discharge orifice of the nozzle were to
remain fixed, the
"k" of the nozzle would remain fixed and flow rate would "tend" to remain
fixed while
discharge pressure would vary with supply pressure. (Flow rate varies only
with the
square root of pressure.).
If a foam concentrate is to be metered into a fluid stream at a constant
percent (eg
3 %, or 6%), a relatively constant flow rate of the fluid stream is an
advantage, as it allows
a metering device on the foam concentrate to be set. Further, a relatively
constant flow
rate with a high discharge pressure may be desired in some circumstances. E.g.
high
pressure helps some concentrate to create a better foam. In a nozzle that
discharges a
chemical, such as a dry powder, within a fire fighting fluid, it may be
desirable to limit
fluid flow rate to avoid unnecessary wetting of the powder. Further, nozzles
that adjust
without limitation to produce a selected discharge pressure can waste water if
there is a
limited supply of water.
Thus, a relatively constant flow rate from a nozzle can be an advantage in
several
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situations, but if the supply pressure is weak, or if a nozzle is set at a
fixed distance from
a fire, a relatively constant pressure may be an advantage. (Constant pressure
tends to
maintain range for the nozzle even though flow rate may vary). Within the
duration of one
fire, the relative importance of constant pressure and of constant flow rate
can shift.
The hybrid, selectively automatic nozzle of the instant invention provides the
best
of two worlds. The adjustable stop (or any other such adjustable means) can be
set so
that an automatically adjustable discharge orifice is provided, as in an
automatic nozzle,
for flow rates up to a given point (in a nozzle's effective flow window). If
supply
pressure goes low, range can be maintained. However, if a targeted fluid flow
rate within
the nozzle is reached, a stop or the like causes the discharge orifice to
cease adjusting.
Now discharge pressure rises with supply pressure but fluid flow rate tends to
remain
approximately constant (again, rising only in proportion to the square root of
the
pressure). Metering foam concentrate in a preselected proportion is thus more
reliable,
with fixed flow rate.
SUMMARY OF THE INVENTION
The invention includes a selectively automatic fire fighting nozzle comprising
a
nozzle body having a conduit terminating in a discharge orifice. The discharge
orifice is
automatically adjustable within a range. The nozzle body includes a stop or
the like,
adjustable to limit a range of automatic adjustment of the orifice. This stop
could be any
adjustable means, simple or complex, for limiting the range of automatic
adjustment of the
orifice. Preferably the stop or adjustable means is located upon the nozzle
body and
divides a nozzle effective flow window such that the nozzle flows at variable
flow
rate/constant pressure for flow rates up to a targeted flow rate, and flows at
variable
pressure/constant flow rate as long as the targeted flow rate is needed.
The invention includes a method for operating an automatic fire fighting
nozzle
comprising (approximately) maintaining a selected fire fighting fluid
discharge pressure
for fluid flowing through the nozzle for flow up to a targeted rate and
allowing discharge
pressure to rise above selected discharge pressure as long as the targeted
flow rate is
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reached. The selectively automatic fire fighting nozzle is also preferably a
self -educting
foam fog nozzle and even more preferably, a self metering self-educting foam
fog nozzle.
In accordance with one embodiment of the present invention, there is provided
a
selectively automatic fire fighting nozzle, comprising:
a body portion of the nozzle defining a fire fighting fluid conduit
terminating in an
adjustable discharge orifice;
the adjustable discharge orifice defined, at least in part, by elements that
relatively
adjust, automatically, over an available range; and
a stop, attached to the nozzle at or downstream of the discharge orifice,
adjustable to
further limit, within the available range, the range of automatic relative
adjustment between
orifice defining elements.
In accordance with another embodiment of the present invention, there is
provided a
selectively automatic fire fighting nozzle, comprising:
a body portion of the nozzle defining a fire fighting fluid conduit
terminating in an
annular adjustable discharge orifice, the fire fighting fluid conduit and
annular orifice
surrounding a secondary fluid conduit and secondary fluid discharge orifice;
the adjustable discharge orifice automatically adjustable within an available
range;
and
adjustable means attached to the nozzle at or downstream of the discharge
orifice, for
further limiting the range of automatic adjustment of the orifice within the
available range.
In accordance with a further embodiment of the present invention, there is
provided a
method of operating an automatic fire fighting nozzle having an automatically
varying
discharge orifice, the nozzle subject to varying supply pressures, comprising:
targeting a flow rate less than a maximum possible flow rate for the nozzle
operating
at a standard supply pressure, wherein said maximum possible flow rate
corresponds to a
maximum opening of the discharge orifice provided by nozzle structure;
maintaining approximately a selected fire fighting fluid discharge pressure
for fire
fighting fluid flowing through the nozzle for fluid flow rates up to
approximately the targeted
flow rate; and
allowing fluid discharge pressure to rise above the selected discharge
pressure while
maintaining approximately fluid flow rate upon reaching the targeted flow
rate; and
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and wherein the allowing is accomplished with structure attached to the nozzle
at or
downstream of the discharge orifice.
In accordance with a further embodiment of the present invention, there is
provided a
selectively automatic fire fighting nozzle, comprising:
a body portion of the nozzle defining a fire fighting fluid conduit
terminating in an
adjustable discharge orifice;
the adjustable discharge orifice defined at least in part by elements that
relatively
adjust, automatically, over an available range;
a stop attached to the nozzle at or downstream of the discharge orifice,
adjustable to
further limit a range of automatic relative adjustment between orifice
defining elements
within the available range; and
wherein a flow window is defined by an effective range of adjustment of the
adjustable discharge orifice and wherein the stop is adjustably located on the
nozzle to divide
the flow window such that the nozzle flows at a variable flow rate and at
approximately
constant pressure for a first lower flow rate fraction of the flow window and
at a variable
pressure and relatively constant flow rate for a second higher flow rate
fraction of the flow
window.
In accordance with a further embodiment of the present invention, there is
provided a
selectively automatic fire fighting nozzle, comprising:
a body portion of the nozzle defining a fire fighting fluid conduit
terminating in an
adjustable discharge orifice;
the adjustable discharge orifice defined at least in part by elements that
relatively
adjust, automatically, over an available range;
a stop attached to the nozzle at or downstream of the discharge orifice,
adjustable to
further limit range of automatic relative adjustment between orifice defining
elements within
the available range; and
wherein the stop limits forward motion of a floating bafflehead over a piston
fixed to
the nozzle, the floating bafflehead and piston defining at least in part an
adjustable baffle
chamber, the stop being attached to the piston.
In accordance with a further embodiment of the present invention, there is
provided a
method of operating an automatic fire fighting nozzle subject to varying
supply pressures
comprising:
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maintaining approximately a selected fire fighting fluid discharge pressure
for fire
fighting fluid flowing through the nozzle for fluid flow rates up to a
targeted flow rate while
flowing foam concentrate or dry chemical through a central conduit of the
nozzle;
allowing fluid discharge pressure to rise above the selected discharge
pressure while
maintaining approximately fluid flow rate upon reaching a targeted flow rate;
and
allowing said pressure to rise by limiting the adjustment of an automatically
adjustable discharge orifice within an available range of adjustment of the
orifice;
and wherein the allowing is accomplished with structure that is attached to
the nozzle
at or downstream of the discharge orifice.
In accordance with a further embodiment of the present invention, there is
provided a
selectively automatic fire fighting nozzle, comprising:
a nozzle body defining a fire fighting fluid conduit terminating annular
adjustable
discharge orifice, the fire fighting fluid conduit and annular orifice
surrounding a secondary
fluid conduit and secondary fluid discharge orifice, the orifice varying
between a minimum
and maximum opening at least in part in response to variation in fire fighting
fluid pressure;
and
nozzle elements, at least in part adjustable, providing a selectively variable
range for
the maximum orifice opening, including a stop attached to the nozzle at or
downstream of the
discharge orifice.
In accordance with a further embodiment of the present invention, there is
provided a
selectively automatic fire fighting nozzle, comprising:
a nozzle body defining a fire fighting fluid conduit terminating in a variable
discharge
orifice, the orifice automatically varying within a variable range, between a
minimum and a
maximum opening, at least in part in response to variation in fire fighting
fluid pressure;
the fire fighting fluid conduit and annular orifice surrounding a secondary
fluid
conduit and secondary fluid discharge orifice; and
selectively variable means attached to the nozzle body at or downstream of the
discharge orifice for varying the range of automatic adjustment of the
orifice.
In accordance with a further embodiment of the present invention, there is
provided a
method of operating an automatic fire fighting nozzle subject to varying
supply pressures
comprising:
targeting a flow rate less than a maximum flow rate possible for the nozzle
when
operating at a standard supply pressure;
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maintaining approximately a constant fire fighting fluid discharge pressure
for fire
fighting fluid flow rates less than and up to approximately the targeted flow
rate; and
allowing fluid discharge pressure to rise above the constant discharge
pressure for fire
fighting fluid flow rates at or above the targeted flow rate, thereby
maintaining fluid flow rate
approximately constant;
wherein the maintaining utilizes a floating bafflehead and a piston fixed to
the nozzle
to create an adjustable baffle chamber;
and wherein the allowing is accomplished with structure attached to the nozzle
at or
downstream of the discharge orifice.
In accordance with a further embodiment of the present invention, there is
provided a
selectively automatic fire fighting nozzle, comprising:
a nozzle body defining a fire fighting fluid conduit terminating in a variable
discharge
orifice, the fire fighting fluid conduit and annular orifice surrounding a
secondary fluid
conduit and secondary fluid discharge orifice, the adjustable orifice
automatically varying
between a minimum and a maximum at least in part in response to variation in
fire fighting
fluid pressure, nozzle elements adjustable to selectively vary a range of
automatic adjustment
of the discharge orifice; and
wherein a flow window is defined by a maximum range of adjustment of the
discharge orifice and wherein at least one stop is adjustably locatable on the
nozzle to divide
the flow window such that the nozzle flows at a variable flow rate and at
approximately a
constant pressure for lower flow rates and at a variable pressure and
relatively constant flow
rate for higher flow rates, the stop attached to the nozzle at or downstream
of the discharge
orifice and wherein the stop limits forward motion of a floating bafflehead
over a piston fixed
to the nozzle, the floating bafflehead and piston defining at least in part an
adjustable baffle
chamber, the stop being attached to the piston.
In accordance with a further embodiment of the present invention, there is
provided a
selectively automatic fire fighting nozzle, comprising:
a nozzle body defining a fire fighting fluid conduit terminating in a variable
discharge
orifice;
the discharge orifice, automatically varying, in response at least in part to
fire fighting
fluid pressure, over a range of openings defined by nozzle elements; and
the range having a selectively variable maximum position, effected in part by
a stop
attached to the nozzle attached at or downstream of the discharge orifice.
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In accordance with a further embodiment of the present invention, there is
provided a
method of operating an automatic fire fighting nozzle subject to varying
supply pressures
comprising:
selecting a targeted fluid flow rate for the nozzle, the target being below a
maximum
flow rate for the nozzle, the maximum being defined at least in part by a
maximum
selectively variable opening of a discharge orifice of the nozzle;
maintaining (approximately) a selected fire fighting fluid discharge pressure
for fire
fighting fluid flowing through the nozzle for fluid flow rates below and up to
the targeted
flow rate;
allowing fluid discharge pressure to rise above the selected discharge
pressure while
maintaining fluid flow rate approximately constant upon reaching and exceeding
a targeted
flow rate, and
allowing said pressure to rise by limiting adjustment of an automatically
adjustable
discharge orifice within a selectively variable range of adjustment of the
orifice
and wherein the allowing is accomplished with structure that is attached to
the nozzle
at or downstream of the discharge orifice.
In accordance with a further embodiment of the present invention, there is
provided a
selectively automatic fire fighting nozzle, comprising:
a nozzle body defining a fire fighting fluid conduit terminating in a
discharge
orifice, the fire fighting fluid conduit and annular orifice surrounding a
secondary fluid
conduit and secondary fluid discharge orifice;
the discharge orifice defined at least in part by elements that relatively
adjust
automatically, over a range; and
a stop, attached to the nozzle at or downstream of the discharge orifice,
selectively
adjustable to limit a range of automatic relative adjustment between orifice
defining
elements.
In accordance with a further embodiment of the present invention, there is
provided a
selectively automatic fire fighting nozzle, comprising:
a nozzle body defining a fire fighting fluid conduit terminating in a
discharge orifice;
the discharge orifice automatically adjustable within a range; and
selectively adjustable means attached to the nozzle at or downstream of the
discharge
orifice for limiting the range of automatic adjustment of the orifice;
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and wherein the means includes a stop limiting forward motion of a floating
bafflehead over a piston fixed to the nozzle, the floating bafflehead and
piston defining at
least in part an adjustable baffle chamber, the stop being attached to the
piston.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the present invention can be obtained when the
following
detailed description of preferred embodiments are considered in conjunction
with the
following drawings, in which:
Figures IA, I B, and 1C illustrate in cutaway all embodiment for a selectively
automatic fire fighting nozzle with flow stop.
Figure 2A illustrates an embodiment of a selectively automatic fire fighting
nozzle
having a flood plate, suitable for only foam educting technique.
Figure 2B illustrates an embodiment of a selectively automatic fire fighting
nozzle
suitable for one embodiment of a chemical application.
Figures 3A and 3B illustrate a set of stops structured for a nozzle to target
different
flow rates.
The drawings are primarily illustrative. It should be understood that
structure may
have been simplified and details omitted in order to convey certain aspects of
the invention.
Scale may be sacrificed to clarity.
Detailed Description of the Preferred Embodiments
In general, a nozzle having an "adjustable" baffle in order to discharge fire
extinghishing fluid at a selected pressure uses a biasing means opposing a
natural movement
of an adjustable baffle outwards in response to fluid pressure, which outward
movement
tends to open the effective size of a discharge orifice. Most simply, the
biasing means biases
with a backward force equal to the force of the desired or selected fluid
pressure upon the
forward baffle surfaces. Hence baffle forward movement balances against baffle
backward
bias pressure at the selected pressure. Forward baffle surfaces are surfaces
that the baffle
presents to the fire extinguishing fluid moving through and out of the
discharge port.
In theory, the biasing force could be provided by a spring that, over the
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adjustment range of the baffle between its end points, which may be no more
than
approximately one half of an inch, presents an essentially constant biasing
force at the
selected pressure. The selected. pressure might wellbe 100 psi. Alternately,
an adjustable
bafilehead could be designed defining a chamber within the baffehead and
presenting
forward and backward surfaces against which the primaryfire extinguishing
fluid could
act. It is understood that the chamber defined within the baffiehead would
have means for
permitting a portion of the fire extinguishing fluid to enter the chamber. In
such designs
the effective backward pressure surface area would usually exceed the
effective forward
pressure surface area of the baffle. The fluid pressure within the baffie,
however, is
expected to be. at least slightly less than the pressure exerted on forward-
facing baffle
surfaces. Such tends to counter the fact that the backward pressure surface
area presented
to the fluid within the baffle, at least in preferred. embodiments herein,
exceeds the forward
pressure surface area presented on the baffle. In such manner the fluid within
the baffle
acts against a greater surface area and, although lower in value, can
potentially drive the
baffle backwards against the flow of fluid through the nozzle. Anticipating
the difference
between the pressures, without and within the baffle, at different source
pressures, and
anticipating the differencein the effective areas presented to the fluid
pressures at different
head pressures and flow rates, leads to a design for a "balanced baffle" at a
targeted fluid
pressure. Spring mechanisms can always be added, it should be understood, to
augment
J the biasing forces provided by the primary fire extinguishing fluid pressure
upon the
bafllehead forward and backward surfaces. If or when baffle adjustment results
in a
variation of the volume of the defined baffle chamber, as by the baffle
sliding over a fixed
piston, relief will be provided to vent fluid from inside the chamber.
Reference is made to the patent applications for more complete discussions and
illustrations. Those applications disclose in particular the use of at least
one relief
valve in order to heighten the accuracy and speed of balance and to lessen
undue
hunting or hysteresis. A relief valve vents fluid pressure from one or the
other side of
the baffle, preferably from within the baffle chamber, when fluid pressure
varies from
target pressure. Such venting typically causes the baffle to move, as in an
illustrated
case, outward toward one of the baffle location end points. A movement
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outward or toward the outward end direction will cause a decrease in the fluid
pressure
upon the baffle. Such decrease in fluid pressure could cause the relief valve
to again close,
permitting again the buildup of fluid pressure upon the back side of the
baffle. The build
up of fluid pressure upon the back side of the baffle should help adjust the
baffle toward
a balanced position where the fluid pressure on the forward surfaces of the
baffle balances
the fluid pressure on backward surfaces of the baffle, including taking into
account other
biasing elements such as a continuously "bleeding" relief valve and any
springs utilized in
the design.
The relief valves illustrated sense either rather directly the primary fire
extinguishing fluid pressure presented to forward baffle surface areas in the
nozzle or
sense more indirectly a more secondary fluid pressure generated within a
chamber within
the baffle. The difference between such designs, or other designs that could
occur to
those of skill in the art, can largely be a matter of design choice and
simplicity of
engineering.
One function selected for a reliefvalve could be to assist in achieving the
situation
where a balanced pressure position is consistently approached from the same
direction,
which could either be the moving outwardly or the moving inwardly the baffle.
Such a
design may facilitate engineering a higher degree of accuracy around the
balance point
with less hunting and greater speed in achieving balance.
The present invention, as in the referenced and incorporated applications,
also
teaches improved self educting features that are particularly helpful and
useful in a
pressure regulating nozzle, as well as enhanced educting and pressure
regulating designs
that are useful when throwing fluid chemical such as dry powder, with or
without an
automatic nozzle.
In operation, a self-adjusting automatic feature depends upon an adjustable
baffle
that adjusts, at least in significant part, in response to primary fire
fighting fluid pressure
presented both to a forward and a reverse side of a baffle surface. In such a
manner the
baffle operates at least in part as a two-way piston seeking a balanced
pressure position.
The nozzle fluid provides a fluid pressure to act against both sides of the
baffle. The
pressure acting in the reverse direction will be at least a function of the
forward pressure.
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Preferably the reverse pressure surface of the baffle will be larger than the
forward
pressure surface of the baffle. It is recognized that the forward pressure
surface of the
baffle may in fact change and be a function of pressure and fluid flow through
the nozzle
and baffle design and nozzle size. Although it would be possible to design a
baffle having
a balanced position where the targeted pressure forward times the forward
pressure
surface equals the reverse pressure times the reverse pressure surface, such a
balancing
technique is difficult to effect in practice. Hence, preferred embodiments
utilize at least
one relief valve. Preferred embodiments further utilize a relief valve to
relieve pressure
in the reverse direction. In preferred embodiments the area of the reverse
pressure surface
is greater than the area of the forward pressure surface. Thus, in preferred
embodiments
when the relief valve is closed, in general, the reverse pressure times the
area of the
reverse pressure surface will be greater than the forward pressure times the
area of the
forward baffle surface. This will dictate that for significant values of
forward pressure the
nozzle is biased closed. As the baffle closes, the pressure forward at the
bafflehead will
tend toward its maximum deliverable pressure in the nozzle. At some point near
the
forward target pressure, one or more relief valves begin to open relieving
pressure on the
reverse side of the baffle and allowing the bafflehead to balance onto open
and adjust
outward. Preferably the relief valve builds in a degree of adjustability such
that the relief
valve can select a partially opened position and settle upon such position
without undue
hunting and wherein the target pressure times the forward surface at the
target pressure
equals the reverse pressure times the reverse pressure surface area taking
into account the
degree of openness of the relief valve system.
Figures 1A, 1B, 1C, 2A. 2B, 3A and 3B illustrate embodiments of the instant
invention, a selectively automatic fire fighting nozzle. The embodiment of
Figures IA-C,
2A, B and 3A herein are analogous to the embodiments of Figure 3A, Figure 3D,
Figures
4C, 4D, 5A, 5B, 5C and 6, of the applications referenced and incorporated
above. The
instant Figures lA, lB and IC illustrate a pilot valve 42 situated in piston
26. Floating
bafflehead B moves outward, as controlled by pilot valve 42, to the right to
widen gap
220. Figure IA illustrates a gap 220 suitable to flow 1,000 GPM while Figure
1B
illustrates a gap 220 suitable to flow 2,000 GPM and Figure 1C illustrates a
gap 220
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suitable to flow 4,000 GPM. Water W flows through the nozzle body in Figures 1
from
left to right. Foam concentrate FC or chemical C flows through the
foam/chemical tube
28. New in Figures 1A, lB and 1C, as opposed to Figures 3-6 of the prior
applications,
is flow stop ST. The flow stop is shown set for a "4,000 GPM" gap 220 size,
illustrated
in Figure 1C. In the preferred embodiment shown, flow stop ST is conveniently
affixed
to a portion of piston 26. When an inside surface of floating bafflehead B
reaches or
contacts flow stop SD, floating bafflehead B ceases to further adjust outward
or to the
right. If water supply and pressure increases, the gap will remain as in
Figure I OC. Flow
rate will remain approximately 4,000 GPM while discharge pressure will rise.
Pilot valve
42 is presumed to be set at some pre-selected pressure such as 100 psi. As in
previous
nozzles, when the water supply and pressure from the source produce a pressure
at the
bafflehead greater than the pre-selected pressure, pilot valve 42 leaks fluid
from the baffle
chamber and floating bafflehead B moves out, or downstream, widening the gap
created
between the floating bafflehead B and the nozzle body. In all three drawings
pattern
control sleeve S is shown, as is customary for a fog nozzle. For clarity the
sleeve is
always shown in the "fog" pattern position.
Figures 2A and 2B illustrate embodiments similar to Figures 1A-1C. Figures 2A,
2B, 3A and 3B show a flood plate 300 attached by pins 308 to floating
bafflehead B. The
flood plate can be adjusted for a foam application, as in Figures 2A and 3B.
In this
instance plug 302 is attached to flood plate 300. Alternately, the nozzle can
be adjusted
for a hydrochemical application, as in Figures 2B and 3A, in which case
chemical
extension tube 304 is affixed to flood plate 300. Adjustable chemical flow
chokes 306
are usually provided with a chemical extension tube 304. The nozzle embodiment
of
Figures 2B and 3 A is thus adapted to throw not only water but dry chemical.
The nozzle
embodiment of Figure 2A is adapted to throw not only water but foam
concentrate. In
Figures 2A and 2B a flow stop ST illustrated in Figures 3A and 3Bis shown
achieving a
full closed position for the nozzle. Alternate flow stops ST can installed, by
the design
of the preferred embodiment to permit bafflehead B to move out into the
positions
illustrated in Figures IA, 1B, 1C, 3A and 3B.
In the preferred embodiment illustrated in Figure 3 a set of stops ST are
provided,
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each stop with a different shank length to govern a different gap size.
Alternately,
however, one stop could be provided adjustable as by screwing. Other
equivalent means
could be utilized to place a limit on a floating bafflehead or the like in its
forward or
downstream movement.
The nozzle show in Figures 2A and 3B are adaptable to be used with a self-
metering self-educting nozzle as disclosed more fully in the above referenced
and
incorporated patent application.
In operation, the adjustable nozzle would be presumed to set to target a
preselected discharge pressure such as 100 psi. The operator, as in the
preferred
embodiment ofFigures 3 and 3B, will select a stop that approximately targets a
given flow
rate. The operator will affix the stop in the position provided in the fixed
piston. The
floating bafflehead will then maintain a fixed pressure until the bafflehead
is stopped by
abutting the end of the flow stop that extends through the piston into the
baffle chamber.
Thereafter, if supply pressure rises and supply flow is adequate, the
discharge pressure at
the nozzle will rise. The gap will remain constant and the flow rate will
remain
approximately constant.
While there are shown and described present preferred embodiments of the
invention, it is to be distinctly understood that the invention is not limited
thereto, but may
otherwise variously embodied and practiced within the scope of the following
claims.
The foregoing disclosure and description of the invention are illustrative and
explanatory thereof, and various changes in the size, shape, and materials, as
well as in the
details of the illustrated system may be made without departing from the
spirit of the
invention. The invention is claimed using terminology that depends upon a
historic
presumptive presentation that recitation of a single element covers one or
more, and
recitation of two elements covers two or more, and the like.
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