Storage tank fire extinguishing apparatus

Apparatus for fighting fires within storage tanks includes a frame movably coupled to the lip of the storage tank. The frame includes rotatable members by which the frame may be moved around the lip of the storage tank. Attached to the frame is a holding device adapted to hold a fire extinguisher nozzle on the interior of the storage tank so as to direct fire extinguishing agents down the inside face of the storage tank. The apparatus may include a fire detector to detect the presence and location of the fire, propulsion means to automatically move the apparatus around the storage tank to a location adjacent to the fire source, and a storage tank for storing fire suppressing agents be used to extinguish the fire.

BACKGROUND OF THE INVENTION 
This invention relates to apparatus for extinguishing a fire in a storage 
tank. More particularly, this invention relates to a fire extinguishing 
mechanism movably coupled to the lip of an oil storage tank so that the 
apparatus can move around the storage tank lip to an appropriate location 
to direct fire suppressant material on the fire. 
With the increasing use of petrochemical substances in our society, 
petrochemical storage tanks are being located in a wide variety of work 
locations, such as tank "farms", factories, process plants, refineries, 
etc. Fire hazards associated with such storage tanks are well known and 
must be adequately addressed before the tanks can be properly positioned 
in any work environment. In large storage tank farms, the fire hazard is 
exacerbated by the great number of tanks requiring fire 
detection/suppression, and the possibility of fire being transmitted from 
one tank to the next. Therefore, it is essential that apparatus be 
provided which is capable of quickly and efficiently suppressing a fire 
ignited on the inside of a petrochemical storage tank. 
The typical petrochemical storage tank is cylindrical in shape and has a 
roof which floats on the petrochemical stored within the tank. The 
floating roof includes flexible seals at its periphery to movably seal the 
floating roof to the inside of the storage tank. It is at this periphery 
that the greatest danger of fire exists. Fires in such floating roof tanks 
is usually ignited and sustained at the gap between the floating roof 
periphery and the interior wall of the tank. It is therefore essential to 
quickly and efficiently place fire suppressant materials around the 
interior surface of the petrochemical storage tank. 
Many fire suppression systems are known which actively suppress a fire in a 
floating roof oil storage tank. U.S. Pat. No. 3,896,881 to De Boer 
discloses an automatic fire extinguisher having a fluid distribution pipe 
network extending around the periphery of the floating roof. This pipe 
network carries fire extinguisher materials around the periphery of the 
floating roof. A plurality of fire extinguisher storage tanks are coupled 
to the pipe distribution network at various locations around the floating 
roof. The pipe distribution network includes a plurality of sprinklers 
which direct the fire suppressant material to the gap between the floating 
roof and the inside wall of the storage tank. Each sprinkler is designed 
to open at a given temperature so that the system automatically detects 
and responds to a fire inside the storage tank. De Boer even proposes a 
second pipe distribution network having sprinklers which operate at a 
different temperature than the sprinklers of the first network. Thus, 
fires of different intensities may be fought with this apparatus. 
However, the distributed sprinkler apparatus according to De Boer is 
incapable of providing a large quantity of fire suppressant material 
directly onto a fire. Each sprinkler of De Boer is only capable of 
providing a fixed amount of fire suppressant material at a given location. 
If the fire is very intense at a specific location, it is possible that 
insufficient fire suppressant material will be provided to extinguish the 
blaze. In addition, the apparatus according to De Boer is adapted to be 
permanently fixed to the floating roof inside the storage tank. This 
greatly adds to the time and expense necessary to manufacture these 
floating roofs. Existing storage tank roofs would have to be extensively 
modified to practice the invention according to the apparatus of De Boer. 
Finally, the De Boer apparatus cannot be moved from tank to tank in 
response to fire conditions. Thus, the cost of each storage tank is 
greatly increased and the majority of the De Boer apparatuses will never 
be used since the majority of oil storage tanks never catch fire. 
U.S. Pat. No. 1,955,265 to Warnock solves some of the above-discussed 
problems by providing a foam applicator capable of being moved from tank 
to tank in response to a given fire condition. As depicted in FIG. 1, the 
apparatus according to Warnock provides apparatus used to hoist the foam 
nozzle over the lip of the oil storage tank. Hook 3 is coupled to the lip 
of the storage tank while block and tackle 22, 23, and 24 are manipulated 
to hoist foam nozzle 21 over the lip of the tank. However, as can be 
appreciated from FIG. 5, once the foam nozzle has been positioned it is 
very difficult to move the foam nozzle around the lip of the tank. Thus, 
where the fire has been suppressed at one portion of the storage tank, the 
Warnock apparatus requires a difficult and time consuming effort to move 
the nozzle to another location on the tank. While the nozzle is being 
moved, it is entirely probably that the fire will be reignited in the 
already-extinguished portions of the tank. 
Therefore, it is apparent that what is needed is a storage tank 
fire-suppression apparatus which is capable of being inexpensively 
manufactured, easily transported to the storage tank, and coupled to the 
storage tank in such a way as to enable the fire suppressant material to 
be quickly applied directly at the location of the fire. Such an apparatus 
should be movable around the tank so that fire extinguishing materials may 
be quickly and accurately directed to the fire source. 
SUMMARY OF THE INVENTION 
In order to overcome the above-discussed disadvantages of known storage 
tank fire extinguishing devices, the present invention provides an 
apparatus which is movably coupled to the lip of the storage tank and 
holds a fire extinguisher nozzle directed toward the interior surface of 
the tank. The apparatus is movable around the lip of the storage tank so 
that the fire extinguisher may be accurately directed to the fire source. 
Preferably, the apparatus includes a fire detector which detects the 
presence and location of a fire source within the tank. The apparatus may 
also include propulsion means for driving the apparatus around the lip of 
the storage tank. Control circuitry may be provided to drive the 
propulsion means to a location at which the fire detector senses the 
presence of a fire source. Thus, the apparatus can remotely and 
automatically place fire extinguishing foam directly on the fire source. 
The apparatus according to the present invention may also include a fire 
extinguisher storage tank capable of holding sufficient fire extinguishing 
material to suppress a storage tank fire. Thus, the present invention may 
be provided as an independent, remotely activated, automatic fire 
extinguishing system capable of detecting and extinguishing a fire without 
the invention of human fire fighters. Such a system would be coupled to 
the storage tank and would automatically detect and suppress a fire 
breaking out on the interior of the tank.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EXEMPLARY EMBODIMENT 
Referring to FIG. 1, the apparatus according to the present invention 
provides a frame 10 which is movably coupled to the lip 20 of cylindrical 
oil storage tank 2. Those having ordinary skill in this field will 
understand that storage tanks may come in a wide variety of sizes and 
shapes, to include cylindrical, curvelinear, octagonal, etc. It is to be 
understood that this invention is directed toward a fire extinguishing 
apparatus which may be used with any shape of storage tank. 
Frame 10 includes interior frame number 12 adapted to be movably coupled to 
the interior of storage tank 2. Frame 10 also includes top frame member 14 
adapted to be movably coupled to the top of lip 20. Finally, frame 10 
includes exterior frame members such as struts 16, plate 17, and top bar 
18. Coupled to top bar 18 is a extinguisher nozzle clamp 22 which is 
adapted to hold a fire extinguisher nozzle 24. As depicted in FIG. 1, fire 
nozzle 24 is positioned to direct fire suppressant materials to the 
interior face of storage tank 2. Thus, the fire suppressant material is 
directed at the flexible seal between the periphery of the floating roof 
and the interior surface of the cylindrical tank. 
Interior frame 12 includes four rollers. Rollers 26 and 28 are provided on 
one side of interior frame 12, while rollers 30 and 32 (not shown) are 
provided at the other side. These rollers are freely rotatable and provide 
support for the apparatus as it moves around lip 20 of the storage tank 2. 
Top frame 14 includes rollers 34 and 36 (not shown) which act to support 
the weight of the apparatus on the top of lip 20. 
Each of struts 16 includes a roller 38 (see FIG. 2) coupled at one end of 
the strut. This roller is adapted to contact the exterior surface of 
storage tank 2 and to be rotatable therearound. 
In operation, the apparatus is placed over lip 20 of storage tank 2 and 
then moved therealong until the fire extinguisher nozzle 24 is 
appropriately positioned to fight the fire inside the tank. Thus, to move 
the fire extinguisher nozzle 24 from one location to another merely 
requires the apparatus to be pushed or pulled in the proper direction. For 
this purpose, plate 17 may have a hole 19 therein through which a rope may 
be tied so that a person on the ground may pull the apparatus to the 
appropriate location. Once the apparatus is properly positioned, fire 
extinguishing foam may be provided to the fire extinguishing nozzle 24 
from a convenient location outside the tank. The fire suppressant material 
may be provided to nozzle 24 by means of a flexible hose or other 
acceptable transmission line (not shown). 
As a modification to the basic structure, the apparatus according to the 
present invention may include a fire sensor 50 coupled to interior frame 
12. Fire sensor 50 is capable of detecting the presence and/or the 
location of a fire in the interior of storage tank 2. Fire sensor 50 may 
be conveniently mounted to interior frame 12, fire extinguishes nozzle 24, 
top frame 14, or any location convenient and practical to a given fire 
hazard situation. Fire detector 50 may be a single detector or a plurality 
of fire detectors using such technology as infra-red heat detection, 
optical detection, smoke detection, etc. A combination of such sensors, 
located together or separates by a given distance, may be used to more 
accurately determine the location of a fire source. Those having skill in 
this field will readily appreciate the wide variety of fire sensors which 
may be used within this system. 
The apparatus according to the present invention may also include control 
system 52 (see FIG. 2), shown coupled to plate 17. Control system 52 
includes electronic circuitry which is coupled (via wire 51) to receive 
fire detection signals from fire detector 50. Control system 52 provides 
useable electrical signals which may be used to properly locate fire 
suppression nozzle 24 over the fire source. These usable electrical 
signals may include, but are not limited to, visual and/or audible 
direction signals which indicate to a fire fighter on the ground outside 
of the tank in which direction to push/pull the apparatus; visual and/or 
audible fire intensity signals used to alert the fire fighter as to the 
quantity or type of fire suppression material required; propulsion signals 
used to command a propulsion device (to be described later) to 
automatically drive the apparatus around the lip of the storage tank; and 
valve actuating signals to open a valve (not shown) in fire extinguisher 
nozzle 24 to automatically begin providing fire extinguishing material to 
the interior of the tank. Persons of ordinary skill in the field will 
quickly understand the types of usable electrical signals which may be 
provided by control system 52 and the variety of uses to which these 
signals may be applied. 
FIG. 2 is a side elevation drawing of the apparatus according to FIG. 1. 
FIG. 2 depicts interior rollers 26 and 28 coupled to interior frame member 
12. Top roller 34 is coupled to top frame member 14 and rests upon the top 
of lip 20. 
FIG. 2 clearly shows that top bar 18 and struts 16 are used to 
counter-balance the weight of the apparatus against the outside of tank 2. 
Thus, a roller 38 is provided at the end of each strut 16 and abuts the 
exterior wall of tank 2. With this configuration of rollers on the inside, 
top, and outside of the storage tank, a stable and steady structure may be 
provided. Thus, the force generated by the fire extinguishing material 
rushing through the nozzle and the weight of the device itself will be 
properly counter balanced. 
While the presently preferred embodiment includes rollers for movably 
contacting the storage tank 2, persons of ordinary skill in this field 
will recognize that any types of movable members may be provided. For 
example, ball bearings, caterpiller tractors, slip bearings, or other 
members may be used to provide movable coupling between the apparatus and 
storage tank 2. 
As used in the specification and claims, the word "coupling" is used to 
define a physical interrelationship between two elements. This 
relationship may be either a direct contact or an indirect contact. For 
example, the apparatus is directly coupled to the storage tank while the 
nozzle holding device 22 is indirectly coupled to the storage tank (via 
top bar 18 and top frame member 14, etc.). Nevertheless, both elements are 
"coupled to" the storage tank. 
FIG. 3 is a perspective view of a second embodiment according to the 
present invention. In this embodiment, propulsion device 60 is mounted to 
the apparatus outside the storage tank. Propulsion device 60 is coupled to 
struts 16 and top bar 18. Propulsion device 60 may be, for example, a 
battery-powered DC motor capable of forward and reverse rotation. 
Coupled to motor 60 is drive wheel 62 which frictionally engages the 
exterior of storage tank 2 to propell the apparatus around lip 20 of 
storage tank 2. Drive wheel 62 may be driven in either the clockwise or 
counter clockwise direction in order to drive the apparatus to a given 
location on the tank lip. The propulsion device 60 may be controlled 
through a remote control device positioned outside the tank near the 
ground (not shown). Thus, a firefighter on the ground outside the tank can 
"drive" the apparatus to a specific location on the tank lip. 
Preferably, propulsion device 60 is coupled to control means 52 and is 
responsive to the fire detection signals provided from fire detector 50. 
Thus, when a fire is detected at a given location on the interior of 
storage tank 2, control device 52 will command propulsion device 60 to 
drive the apparatus around the storage tank to a location substantially 
adjacent the detected fire source. In such a fashion, the apparatus 
according the present invention can automatically provide fire suppressant 
material directly on the fire source. Thus, a fire fighter is not required 
to guess the location of the fire source or to attempt to view the 
interior of the burning tank. 
An additional modification which may be provided in the apparatus according 
to FIG. 3 is a storage tank 70 for storing fire suppressant materials. 
Such materials include, but are not limited to, foam, chemicals, powders, 
fluids, etc. As used in the specification and claims, the term "fluid" is 
intended to encompass all such fire suppressant material which may be 
applied through nozzle 24. Such materials may be, for example, aerosols, 
binary chemicals, foam generating chemicals, powders, liquids, etc. 
Fire suppressant storage tank 70 is coupled to nozzle 24 so that fire 
suppressant material stored inside of tank 70 may be provided directly to 
the fire source through the nozzle 24. 
Preferably, either the nozzle 24 or the storage tank 70 includes a valve 
and valve actuator (not shown) which is controlled by control device 52. 
Control device 52 may command the valve to open and close in accordance 
with the fire detection signal received from fire detector 50. Thus, the 
apparatus provides fire suppressant material only so long as a fire source 
is active inside tank 2. 
In a further modification of the apparatus according to FIG. 3, an 
auxiliary pipe 72 and valve 73 may be provided coupled to storage tank 70. 
Thus, storage tank 70 may be refilled through the auxiliary pipe 72 and 
valve 73. Alternatively, should the fire suppressant material in storage 
tank 70 be exhausted, additional fire suppressant material may be provided 
to nozzle 24 through auxiliary pipe 72. Thus, additional fire suppressant 
material may be provided while the fire is being fought. 
The apparatus according to FIG. 3 is thus capable of remotely and 
automatically detecting and extinguishing a fire inside of a storage tank. 
Such an apparatus would eliminate the need for continually monitoring oil 
storage tanks to detect fire therein. The apparatus according to FIG. 3 
may be placed on an oil storage tank and left in place. Should a fire 
occur inside the tank, it will be detected by fire sensor 50, which passes 
a signal to control unit 52. Control unit 52 then commands propulsion 
device 60 to drive the apparatus to a location on the tank lip 
substantially adjacent the detected fire source. Control unit 52 then 
commands the valve inside nozzle 24 or storage tank 70 to open thus 
applying fire suppressant material directly on the source of the fire. 
Control unit 52 will continually move the device to active fire sources 
and dispense fire suppressant materials on those sources until no more 
fire is detected within the interior of the tank. Thus, a storage tank 
fire may be detected and extinguished before a human is even aware of the 
problem. 
In accordance with the present invention, the preferred fire nozzle is a 
JS/10 Aer-o-foam made by the National Foam Company. Alternatively, a 
turbo-jet fog nozzle may be used when using an A.T.C.-type AFFF 
concentrate. With such nozzles, the operating pressure of the fluid 
handling system is approximately 100-150 pounds per square inch. 
According to the present invention, the apparatus without the propulsion 
device 60 or storage tank 70 is designed to weigh less than 75 pounds. 
This light-weight construction allows the apparatus to be quickly moved to 
a particular storage tank and easily hoisted and coupled to the lip of the 
tank. This light-weight structure thus adds to the flexibility and variety 
of uses to which this device may be put. 
While the invention has been described in connection with what is presently 
considered to be the most practical and preferred embodiments, it is to be 
understood that the invention is not limited to the disclosed embodiment 
but, on the contrary is intended to cover various modification and 
equivalent arrangements included within the spirit and scope of the 
appended claims. For example, a separate rail may be fixed to the lip of 
the storage tank, and the apparatus according to the present invention may 
be physical coupled to the rail. However, in such a structure the 
apparatus is still movably coupled (indirectly) to the tank lip. 
Therefore, persons of ordinary skill in this field are to understand that 
all such equivalent structures are to be included within the scope of the 
following claims.