Fire extinguisher

The fire extinguisher includes a container filled with a fire extinguishing liquid and having a normally closed main outlet and support structure extending through an opening of the container wall. A compressed gas cartridge located in the container is supported by the support structure. The support structure has an opening formed therethrough which leads to the end of the compressed gas cartridge. A plunger, an explosive charge, and a heat sensitive fuse, the latter of which has a portion is exposed to the exterior of the container, are located in the opening of the support structure. In the presence of high temperature, the fuse causes the explosive charge to explode and force the plunger to rupture the cartridge which release the gas into the liquid in the container by way of a normally closed gas outlet formed through the wall of the support structure. This causes the liquid to be forced out of the container by way of the normally closed main outlet. In another embodiment, the fire extinguishing material in the container may be a powder.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a fire extinguisher employing a fire extinguishing 
material and a compressed gas cartridge. 
2. Description of the Prior Art 
U.S. Pat. Nos. 1,766,912; 1,898,482; 4,299,289; and 5,551,517 disclose 
different types of fire extinguishers some of which employ a fire 
extinguishing material and a compressed gas cartridge. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a new and useful fire 
extinguisher that employs a fire extinguishing material and a compressed 
gas cartridge. 
The fire extinguisher comprises a container filled with a fire 
extinguishing material and having a normally closed main outlet and 
support structure extending through an opening of the container wall. A 
compressed gas cartridge located in the container is supported by the 
support structure. The support structure has an opening formed 
therethrough which leads to the end of the compressed gas cartridge and 
which supports a plunger, an explosive charge and a heat sensitive fuse, 
the latter of which has a portion exposed to the exterior. In the presence 
of high temperature, the fuse causes the explosive charge to explode and 
force the plunger to rupture the cartridge which releases the gas into the 
fire extinguishing material in the container by way of a normally closed 
gas outlet formed through the wall of the support structure. This causes 
the material to be forced out of the container by way of the normally 
closed main outlet. 
In the preferred embodiment, the fire extinguishing material is a liquid.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, the fire extinguisher is illustrated at 21. 
It comprises a round stainless steel container 23 having a cylindrical 
side wall 24, a bottom wall 25 and an upper annular flange 27 having to a 
round aluminum top or lid 29 secured thereto by bolts 31 and nuts 33. The 
top 29 may be secured to the flange 27 by rivets. An annular seal 35 is 
located in an annular slot 37. The container 23 is filled with a fire 
extinguishing liquid 39. 
The bottom 25 has two circular apertures 41 and 43 extending therethrough. 
Extending through the apertures 41 is the upper portion of a liquid outlet 
member 45. Extending through the apertures 43 is a support member 47 for 
supporting a compressed gas container or cartridge 49. The compressed gas 
located in the cartridge preferably is CO.sub.2. The outlet member 45 
comprises a metal member 51 having an cylindrical head 53 with a threaded 
shaft 54 with a central opening 55 extending therethrough. The lower end 
of the shaft 53 has an annular slot 56 formed therein. An annular slot 57 
is formed in the head 53 for receiving an annular seal 58. A metal 
coupling member 61 has a cylindrical wide upper opening 63 with inner 
threads, a cylindrical intermediate opening 67 and a cylindrical lower 
opening 69 with inner threads. The threads of the opening 63 are screwed 
to the threads of the shaft 54 with the edge of the bottom wall 25 around 
the aperture 41 located between the head 53 and the annular surface 70 of 
the member 61 and with an annular seal 71 of a flexible membrane 73 
located in the slot 56 such that the membrane 71 stretches across the 
opening 55, 67. A tubular member 81 has a cylindrical upper end 83 with a 
cylindrical opening 85 formed therethrough and exterior threads which are 
screwed to the inner threads of opening 69. The membrane 71 normally 
closes the opening 55, 67 against the weight of the liquid 49. A spray 
nozzle 87 is formed at the lower end of the member 81. 
The support member 47 comprises a metal member 91 having an upper 
cylindrical shaft 93 with outer threads and an opening formed therethrough 
comprising a cylindrical opening 95 which leads to a smaller cylindrical 
opening 97 which in turn leads to a still smaller cylindrical opening 99 
the latter of which leads to cone shaped opening 101. The support member 
47 also comprises a member 103 having an opening extending therethrough 
which comprises a large cylindrical opening 105 with inner threads and a 
smaller diameter opening 107 with inner threads. The member 103 has an 
outlet opening formed from the opening 107 to the exterior and comprises a 
small diameter opening 109 which leads to a larger diameter opening 111 
defining a seat 113. A rubber ball 115 is press fitted in the opening 111 
against the seat 113. The press fit maintains the ball against the seat 
113. The member 103 has an annular slot 141 for receiving a seal 143. 
The member 91 has an annular slot 121 for receiving an annular seal 123 and 
an annular slot 125 for receiving a seal 127 to which a flexible membrane 
129 is attached. The membrane 129 extends across the junction of openings 
95 and 107. 
A metal plunger 131 with a pointed member 133 is located in the opening 95 
and explosive charge 135 is located in the opening 95. A heat sensitive 
fuse 137 is coupled to the charge 135 and extends through opening 99 to 
the opening 101. 
In assembly, before the fire extinguishing liquid is inserted into the 
container and before the lid 29 is secured in place, a conventional metal 
CO.sub.2 cartridge 49 containing CO.sub.2 under pressure has its threaded 
end 151 screwed to the threads of opening 105 of member 93. The shaft 93 
of member 91 is inserted through the container opening 43 with the 
explosive fuse 137, charge 135, plunger and membrane 129 in place and 
screwed to the threads of opening 105 of member 103 with the seals 123, 
125, and 143 in place and with the ball 115 in place as shown. 
The container 23 then is filled with fire extinguishing liquid 39 and the 
lid 29 secured in place. 
In use, the lid 29 may be secured to an object to suspend the fire 
extinguisher over a structure to be protected such as a stove. If a fire 
occurs, the fuse 137 will ignite after the temperature reaches a given 
high level. This actuates the explosive charge 135 which drives the 
plunger 131 and its pointed member 133 toward the metal end 153 of the 
cartridge 49. The pointed member 133 pierces the membrane 129 and the 
cartridge end 153 releasing the high pressure gas from the cartridge. The 
gas pushes the ball 115 out into the liquid 39 and flows into the liquid 
by way of the opening 109, 111. The pressurized gas in the liquid, causes 
the liquid to rupture the membrane 73 such that the fire extinguishing 
liquid is released for flow through the opening 85 which then sprays 
downward and outward as it flows through the spray end 87. 
The purpose of the membrane 129 is to prevent dust, material, or liquid 
from entering the opening 107 between the membrane 129 and the cartridge 
end 153 during the period when the fire extinguisher is in a storage or 
ready condition awaiting the presence of a fire. 
In one embodiment, the fire extinguishing material 39 may be AFFF which is 
a liquid concentrate added to water, available, commercially from 
Chemguard in Mansfield, Tex.; the explosive charge 131 may be lead 
styphnate; the fuse 137 may be a flame activated primer cord fuse; and the 
cartridge 49 may contain CO.sub.2 at a pressure of about 700 psi at room 
temperature. The outer diameter of the container may be 10 3/4 inches and 
its height may be 10 inches. The membranes 73 and 129 may be formed of a 
commercially available latex material, rubber or an elastomer. 
In another embodiment, instead of a liquid, the fire extinguishing material 
in the container 23 may be bicarbonate powder which is forced out of the 
outlet 45 by the CO.sub.2 when released from the cartridge 49 by the 
plunger when the explosive charge 31 is actuated. The powder acts 
substantially in the same manner as the liquid for fire extinguishing 
purposes.