US3692117A

US3692117A - Method of imparting high pressure to material for extinguishing fires and other purposes

Info

Publication number: US3692117A
Application number: US74085A
Authority: US
Inventors: Arthur G Wright
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-09-21
Filing date: 1970-09-21
Publication date: 1972-09-19
Anticipated expiration: 1989-09-19

Abstract

A method for introducing material under high pressures into selected areas for various purposes which comprises confining non-gaseous carbon dioxide under pressure, applying heat thereto to produce high pressure carbon dioxide gas, conducting the gas into the material and directing the formed high pressure mixture of carbon dioxide gas and material into the selected area. The invention is used to create pressure surges in oil well drilling fluid in a line and for hurling fire retardant material into fires to rapidly extinguish them. A system for extinguishing fires and preventing explosions comprising a source of high pressure carbon dioxide gas for delivering a fire retardant material under high pressure to the point of combustion instantaneously after combustion starts, the high pressure carbon dioxide source being a series of cartridges containing liquified carbon dioxide provided with heater elements for gasifying the liquid carbon dioxide and communicating with a source of fire retardant material in a tank, or with a manifold connected into a line carrying fire retardant material, the tank or the manifold being connected to a delivery channel for delivering fire retardant material to the point of flame. If an oil well fire is involved, the manifold may be connected into the line in which drilling fluid is delivered to an oil well during drilling, the drilling fluid serving as the fire retardant material. Where fires are not involved, the apparatus can be used to create pressure surges in the drilling fluid line for various purposes.

Description

vulevu ueaeva 1 alClll Wright EXTINGUISHING FIRES AND OTHER PURPOSES [72] Inventor: I Arthur G. Wright, Westminster,

[73] Assignee: Donald G. Stroh, Golden, C010. [22] Filed: Sept. 21, 1970 [21] Appl. No.: 74,085

[52] US. Cl. ..169/2 R, 169/15 [51] Int. Cl. ..A62c 3/00 [58] Field of Search ..239/2 R, 15

[56] References Cited UNITED STATES PATENTS 1,157,614 10/1915 Brent ..169/l5- 1,839,658 1/1932 Dugas. ..169/15. 2,740,163 4/1956 Ferguson et a1 ..169/2 R 3,356,148 12/1967 Jamison ..169/15 3,438,445 4/1969 MacCracken 169/2 R 3,495,012 2/1970 I Williamson ..169/2 R 3,515,217 6/1970 Jamison ..169/2 R 3,557,811 l/l97l Livingston ..169/15 3,584,688 6/1971 Duncan et al ..169/2 R Primary Examiner-Lloyd L. King Attorney-Sheridan, Ross and Burton 1 Sept. 19, 1972 ABSTRACT A method for introducing material under high pressures into selected areas for various purposes which A system for extinguishing fires and preventing explosions comprising a source of high pressure carbon "dioxide gas for delivering a fire retardant material under high pressure to the point of combustion instantaneously after combustion starts, the high pressure carbon dioxide source being a series of cartridges containing liquified carbon dioxide provided with heater elements for gasifying the liquid carbon dioxide and communicating with a source of tire retardant material in a tank, or with a manifold connected into a line carrying fire retardant material, the tank or the manifold being connected to a delivery channel for delivering fire retardant material to the point of flame. If an oil well fire is involved, the manifold may be connected into the line in which drilling fluid is delivered to an oil well during drilling, the drilling fluid serving as the fire retardant material. Where fires are not involved, the apparatus can be used to create pressure surges in the drilling fluid line for various purposes.

12 Claims, 7 Drawing Figures 76 so 82 I6 28 24 I2 1 26 74 5 P l V Ooboc$ ooooo V 78 BACKGROUND OF THE INVENTION This invention relates broadly to a method'of extinguishing fires substantially instantaneously after they start by propelling a fire retardant material into the fire at high pressures by means of aninert gas which mixes with the fire retardant, the high velocities resulting from the gas being released at pressures up to 30,000 p.s.i. or more. The invention has particular application to the extinguishing of oil well fires and is illustrated by this application although it is not limited thereto. It can also be used to create pressure surges in the drilling fluid for applications in which fires are not involved.

It is common knowledge that oil well fires caused by blowouts, ignition of combustible gases escaping rela: tively slowly from thewell, and from other sources, are extremely expensive. These fires are extremely hazardous to human life. These fires not only destroy expensive equipment but they cause-large losses resulting from combustion of the valuable gases and oil, and it is extremely expensive to extinguish them by capping, blowout prevention devices and other means.

Oil well fires usually start in fairly restricted areas around the well-head and spread rapidly, in a matter of seconds. If the initial flame can be sensed and extinguished immediately, it results in prevention of large oil well fires in many cases. Because the burning gas is escaping at high velocities and the fire is burning with great intensity, any fire extinguishing expedient used to blanket oxygen from the flame at the initiation of the fire should be performed within seconds from the time the flame appears, and if fire retardant is used it must be hurled into the flame area at tremendous velocity and, therefore, with a great deal of force. Also, the fire retardant material and the gas which propels it should be made at the time of initiation of the fire, but can only be made after disasterous loss of expensive fuel and equipment and with the destruction of the well in many cases.

In the present invention, fire retardant material is propelled into the flame area by an inert gas under high pressures instantaneously after the fire starts. The apparatus for doing this comprises a manifold which can be connected into the drilling fluid line or other line containing fire retardant material, the manifold being provided with a number of liquid carbon dioxide cartridges or carbon dioxide surge booster units communicating with the chamber of the manifold, the units being provided with heater elements to convert the liquid carbon dioxide into gaseous carbon dioxide and with a rupture disc between the liquid carbon dioxide chamber and the chamber of the manifold which bursts when the gaseous carbon dioxide reaches the required pressure (up to 30,000 p.s.i.) to permit passage of the gaseous carbon dioxide into the manifold where it mixes with the drilling fluid, which may be gaseous, or other fire retardant material to propel it down the line to the well-head to extinguish the fire.

When it is not expedient to use the drilling fluid as the fire retardant material, a stand-by manifold type tank is used in which a chamber loaded withfire retardant is charged with the carbon dioxide surge boosters, the tank being connected to a line for transfer of fire retardant material and carbon dioxide gas to the source of the fire. A rupture disc is provided at the tank outlet controlling the release pressure of carbon dioxide gas.

Liquid carbon dioxide cartridges or carbon dioxide surge boosters, as they are referred to in this application, are well known in the art and are illustrated by US. Pat. No. 2,207,191, Geertz. 1

It is well known that these cartridges can be used to instantaneously discharge carbon dioxide gas at high pressures for various purposes to shatter or dislodge material, such as coal from its veins in coal mines or scale from bessemer converter furnace parts, or for other purposes. According to the typical construction of these units, an outer case forms a chamber for storage of liquid carbon dioxide. A chemical heater element is supported in the carbon dioxide chamber provided with a match-head" which can be ignited by an igniter actuated by the introduction of electrical current, to heat the liquid carbon dioxide to its critical temperature to gasify it and create large pressures to rupture a rupture disc at the exit end of the cartridge to permit release of the high pressure gas. Pressures up to 30,000 p.s.i. can be obtained in a matter of milliseconds. It is well known that these pressures are controllable by adjusting the size and strength of the cartridge, the strength of the rupture disc, the size of the discharge orifices, and other parameters as set forth in the Geertz patent referred to above. In accordance with this invention, the high pressure carbon dioxide gas is ejected into a manifold containing fire retardant material where it mixes with it and forces it into the flame area under high pressure and at high velocity.

Carbon dioxide is an inert gas and is itself used as fire extinguishing material in ordinary fire extinguishers and in other equipment. Fire extinguishers using liquid carbon dioxide as the source of relatively low pressure carbon dioxide gas are well known. In this invention, the use of liquid carbon dioxide to provide high pressure carbon dioxide gas not only supplies the force and velocity to. the fire retardant material necessary for instantly blanketing oxygen from a fire to extinguish it, but it has the additive effect of contributing to the inert atmosphere in the flame area.

Carbon dioxide, as is well known, is incombustible and will not support combustion. This gas has the further advantage that it is soluble in water and other liquids and mixes well with liquid fire retardant material, gases, slurries, drilling fluids, etc. A further advantage of the invention is the fact that no squibs or detonators are necessary and the small amount of flame used to initiate the conversion of liquid carbon dioxide to gaseous carbon dioxide is no fire hazard in the inert environment in which it is used. The pressure created is not the result of an explosion but of the conversion of liquid to gaseous carbon dioxide with the release of a large amount of energy when liquid carbon dioxide is heated to its critical temperature. As a result, there are no problems with detonation waves, and other undesirable problems attendant to the use of explosives for propelling the fire retardant materials.

An appreciation of the high pressures generated in the matter of milliseconds by the carbon dioxide surge booster is gained by reference to the graph of FIG. 7 in which p.s.i. generated in a booster is plotted on the ordinate against time in milliseconds on the abscissa. It is noted that for the rupture disc used, a pressure of 30,000 p.s.i. resulted in a period between 40 and 50 milliseconds.

A further advantage of the invention is the fact that programmed actuation of the carbon dioxide surge boosters can be obtained by standard switching and switch timing devices for activating the circuits for the igniter for the match-head which ignites the chemical heater mixture. This is in contrast to the use of gases maintained in the compressed state, such as, compressed air, wherein expensive sequential valving apparatus is necessary to provide programmed release of compressed gas from the units.

The presence of the flame is preferably sensed with the use of conventional flame, smoke or gas sensors, the sensor being connected to the circuit for actuating the igniter for the match-head for the chemical mixture in the surge boosters. However, manual means can be used for actuating the igniter as there is sometimes a short time interval between the first appearance of the flame and its spread to uncontrollable limits.

A- further feature of the invention is the use of a branch line communicating with the high pressure line carrying the carbon dioxide-fire retardant mixture and a piston or other actuating mechanism of a ram-type blowout preventer so that the blowout preventer is actuated almost simultaneously with the introduction of the high pressure fire retardant into the flame area. Further, the invention contemplates the use of a continuous flow of relatively low pressure carbon dioxide gas in the well-head area during drilling and/or servicing. An additional modification is a surge booster modified to include a tubular section between the liquid carbon dioxide chamber and the discharge head for holding whatever material is desired for propulsion into a selected area by high pressure carbon dioxide gas. A further use of the invention is for supplying a rapid surge of pressure in drilling fluid at a selected area for various purposes other than fire prevention purposes during drilling and servicing of oil wells.

DESCRIPTION OF THE INVENTION The apparatus and method of the invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is a schematic showing of the fire extinguishing system of the invention arranged for extinguishing oil well fires or creating pressure surges in the drilling fluid for other purposes;

FIG. 2 is a side view of a carbon dioxide surge booster manifold used in the apparatus of the invention;

FIG. 3 is a top plan view of the manifold of FIG. 2;

FIG. 4 is a section taken on line 44 of FIG. 2;

FIG. 5 is a cross sectional view of a modified system of the invention;

FIG. 6 is a schematic sequencing circuit diagram for a system of carbon dioxide surge booster units illustrating the sequential and/or selective operation of the booster units, and

FIG. 7 is a graph illustrating the time-pressure buildup for a typical liquid carbon dioxide cartridge or surge booster unit.

In the schematic showing of FIG. 1 of the system or apparatus of the invention constructed and arranged for extinguishing oil well fires, a manifold 10 is connected in a drilling fluid line 12 for delivering drilling fluid to the oil well casing at the well-head 14 during drilling, the system includes a conventional pump 16 for pumping the drilling fluid. Also included in the system is auxiliary liquid carbon dioxide tank 18 and stand-by manifold or tank 20 to be described later. Main line 12 is provided with drain valves 22, operating valves 24 and 26 and check valve 28.

For charging high pressure carbon dioxide gas into the chamber of the manifold 10 upon demand, a series of liquid carbon dioxide cartridge units or surge boosters 30 are removably mounted in the manifold wall. Referring to FIG. 4, the mounting assembly for the cartridge units 30 includes an annular adapter 32 swaged into the manifold wall which is internally threaded to receive the externally threaded end of a casing 34. An internal adapter 36 having internal threads is swaged into the lower end of the housing 34 to receive the externally threaded lower end of cartridge 30. A similar internal adapter 38 is fitted removably into the upper end of the casing 34 and is provided with internal threads to accept external threads on the top of cartridge 30. A cap 40 having internal threads mating with external threads at the top of housing 34 seals the assembly. With the mounting arrangement described, spent cartridges can be removed and replaced.

To provide a better understanding of the invention, the cartridge 30 is shown in some detail in FIG. 5, an auxiliary section 42, not normally a part of the cartridge, being qonnected between the adapter 44 for shell 46 and the discharge head 48. Normally, as in the booster units 30, the discharge head 48 is connected directly to the adapter 44. The charging head is shown at 50, the container for the chemical heater schematically at 52 and the rupture disc for the shell 46 at 54. The electrically actuated igniter element, such as, a match-head, bridge wire, etc. is shown schematically at 56. Electrical actuation of igniter element 56 ignites the Thermit type mixture of the heater element 52 to heat liquid carbon dioxide in chamber 58 to raise it to its critical temperature to convert it to gas with the generation of high pressure to rupture disc 54 to permit escape of gas through outlets 60 in discharge head 48. The surge booster units 30 are each mounted in the wall of the manifold 10 with some of their discharge ports 60 facing toward the downstream end of the manifold.

The pump 16 is of the conventional type, drilling fluid, or gas in gas drilling, being pumped through a circuit including the casing and bit (not shown) and a purification system to clean the fluid of borings, etc. The pump is in communication with a source of gas or drilling fluid (not shown). The drilling fluid may be drilling mud, gas, water or other fluid conventionally used.

For delivering a constant stream of relatively low pressure carbon dioxide gas to the drilling area during drilling and/or servicing to provide an inert atmosphere, an auxiliary feed line 62 is connected between the drilling fluid line 12 and the tank 18 of liquid carbon dioxide, a check valve 64 being inserted in line 62 to check back pressure from line 12 upon actuation of the boosters 30.

The tank 18 is a conventional liquid carbon dioxide storage tank which is refrigerated and insulated to maintain the carbon dioxide as a liquid.

A stand-by tank 20 having a chamber for holding fire retardant material and charged with carbon dioxide cartridges in a similar manner to manifold is connected to the drilling fluid line 12 by line 66 in which is inserted check valve 68 and operating valve 70. The stand-by tank may have the same construction as the manifold 10. A rupture disc 72 is included at the outlet of tank or manifold 20 to control gas and liquid pressure.

A branch line 74 connected to the main line 12 serves to convey high pressure fire retardant material and gaseous carbon dioxide to the operating element of a conventional ram-type blowout preventer 76 when the boosters 30 are activated. The branch line 74 has a rupture disc 78 in it constructed to rupture at about the same pressure as the rupture discs in the carbon dioxide cartridges 30, and a pressure regulating valve 80 to control the pressure in line 74 to the operating pressure of the blowout preventer 76. This pressure can be controlled by other means, such as, the diameter of line 74, etc.

A sensing device 82 is mounted in position with respect to the well-head to detect a fire or conditions which enhance fires at the well-head and is connected through the sequencing circuit of FIG. 6 to actuate the electrical initiating circuits for the initiators 56 for the match-heads in the cartridges 30. L

Referring to FIG. 6, a sequencing circuit for sequentially activating the individual surge boosters 30 in response to actuation of the sensing unit 82 is shown. For example, when a conventional bi-metallic element in the sensor 82 is expanded by heat, it closes the circuit in FIG. 6 to sequentially actuate the stepping switches which are connected to respective initiators 56 of the boosters 30. By means of this circuit, the initiators 56 can be activated selectively,sequentially or in salvo. This type conventional circuitry is, of course, used likewise for the activation of the carbon dioxide surge boosters in the manifold type stand-by tank 20.

The operation of the system for providing an inert atmosphere in the well-head area during drilling and/or servicing and for extinguishing an oil well fires after fire conditions are detected is as follows. During drilling, the drilling fluid is flowing through the drilling fluid circuit including the manifold 10. The actuation circuit of FIG. 6 is set to actuate the initiators in the order desired upon a signal from the sensor 82. Valve 64 is open to permit a continuousflow of relatively low pressure carbon dioxide gas through lines 62 and 12 into the well-head 14 to minimize the occurrence of fire; if a fire condition occurs at the well-head, it is detected by the sensing device 82. The bridge wire or initiator circuits of the surge boosters 30 are activated automatically in the order set into the sequencing circuitry. The chemical heating mixtures in the cartridges 30 are ignited by the initiators 56 to provide intense heat to instantaneously raise all of the liquid carbon dioxide to its critical temperature where it gasifies to produce instantaneous pressures up to 30,000 p.s.i. depending on the construction of the cartridge to break the rupture discs 54.

The gaseous carbon dioxide travels through the outlet holes 60 in the discharge heads 48 of the boosters into the manifold 10 where it contacts the drilling fluid in the manifold to mix with it and force it instantaneously into the well-head area. The carbon dioxide and fire retardant mixture blankets oxygen from the flame area with an inert medium to extinguish the flame. Due to the construction of the cone-shaped ends of the manifold 10, a head of drilling fluid will, of course, be present in the manifold chamber during drilling to supply adequate fluid to serve as fire retardant material. Other constructions can be used to provide the result.

At the same time the rupture disc 78 will be ruptured from the pressure of the gaseous carbon dioxidedrilling fluid mixture in line 12 so that some of this mixture will actuate the piston or other actuating element of a fire prevention ram device 76 to close off the wellhead to prevent further fluid from coming out its end. The

check valves

28, 64 and 68 prevent back flow of high pressure gas and fluid resulting from the high pressure carbon dioxide released from the cartridges 30. V

The stand-by tank 20 can be used in conjunction with the manifold 10 if necessary or it can be used alone. It is available as a stand-by safety measure during pumping, pulling pipe, or during other repair and working operations in which fires may occur from sparks originating from various sources, such .as, friction between metal tools and work pieces, etc. Obviously, the stand-by manifold type tank 20 can be used to extinguish fires from whatever source. It can be made mobile and moved to any sites where fires are already burning to extinguish them. This unit is particularly useful for use around high pressure storage tanks and lines carrying flammable gases or liquids in which leakage frequently occurs at valves and joints. I

Referring to FIG. 5, an auxiliary tubular section 42 for holding a selected fluid or material is connected between the shell 46 and the discharge head 48. The auxiliary section 42 is equipped with rupture discs 84 and 86 serving as closure members for the section 42 to form a container for holding various materials. This construction is preferable to a section having permanent ends as it is reusable merely by supplying new rupture discs after use. The rupture discs 84, 86 can be sealed to the ends of the section 42 by temporary sealing means for filling of the section 42 and storage of the filled section.

The section 42 can be filled with acid and used for acidizing with the unit being lowered into the well to the point of application. It may be filled with other materials of a solvent nature and lowered into the well for cleansing, lowering viscosity of oil and gas cut materials and for removing scale in the well. Any selected material can be loaded into the section 42 to be used for a compatible purpose with application pressure up to 30,000 p.s.i. or more being available from the carbon dioxide cartridge. The unit with the section 42 loaded with fire retardant can be made mobile and positioned as needed for extinguishing localized fires. Similar units can be used with or without a sensor to prevent fires in mines by positioning them near areas where initiation of fires is likely, such as, working surfaces of the mine, to extinguish flames which initiate explosions.

There are various applications of the system shown in FIG. 1 to oil well drilling using gas or fluids in the drilling fluid circuit. In addition to its application to the extinguishing of fires, it can be used to provide a rapid increase of pressure in the drilling fluids or gases to assist in drilling and servicing procedures, such as, to dislodge stuck drill rods or drill tubing and/or drill heads in a safe manner. The apparatus for this application may take other forms than that of FIG. 1. This application with its upsurging features aids in fishing operations in a safe manner. In this type application the pressure from the boosters 30 to provide the surge is controlled by the construction of the boosters as explained above.

In gas drilling operations, the manifold 10 is not connected into the line and the stand-by manifold type tank is used. The manifold and cartridge assembly is in a stand-by condition during drilling and/or servicing when most fires occur and drilling fluid is flowing in the line. In accordance with FIG. 6, selective charging of carbon dioxide cartridges can be effected to bring into play the cartridges as needed without the necessity of expensive valving arrangements. An inert atmosphere is provided in the well-head area during drilling and/or servicing to prevent initiation of fires. When drilling has been halted for pulling casing or doing other work, the stand-by retardant tank or manifold 20 charged with carbon dioxide surge boosters is available to rapidly extinguish fires which may be caused by sparks from workmens tools and other sources igniting the gaseous products coming out the casing at the well-head.

The system shown in FIG. 1 is not critical to the use of the carbon dioxide surge booster principle in extinguishing oil well fires as it is illustrative only of an operative system in which the principle is implemented. Neither is the valving arrangement illustrated and described for the system of FIG. 1 critical as various valving arrangements can be used to accomplish desired objectives. The system shown in FIG. 1 can be used with or without a blowout preventer, or tank 18 and continuous flow of low pressure carbon dioxide gas, or stand-by manifold type tank 20. The timing and sequencing circuitry shown in FIG. 6 is by way of illustration only and other conventional circuity accomplishing the same function can be used.

Although the invention has been illustrated by its application to the prevention and extinguishing of oil well fires, it is not limited to this application as it can obviously be used for extinguishing fires originating from any source. Other inert gases than carbon dioxide can be used, such as, nitrogen, which can be stored in nongaseous form at suitable temperatures and can be readily heated to their critical temperatures to convert them to the gaseous form with production of high pressures. All types of conventional fire retardant materials, including solids, may be used in the manifold 10 and stand-by tank 20. The drilling fluid which serves the added purpose of fire retardant material in case of The invention includes the use of high pressure inert gas alone at the fire area as well as mixtures of inert gas and fire retardant material. Actuation of the initiators in any order desired may be accomplished with or without sensing means and without the use of valving devices. It can be done manually. Examples of conventional sensing means which may be used are those which are actuated by light, gas, temperature, pressure, flame, etc. The invention is most effective in extinguishing oil well fires when the carbon dioxide cartridges are activated instantaneously upon the origin of the fire. Preferably, the mixture of inert gas and fire retardant material is directed at substantially a right angle to the upward pillar of flame at the well-head.

One of the principal advantages of the invention in its application to extinguishing fires is that it provides a blanket of inert fire retardant and carbon dioxide mixture traveling at tremendous speed and under pressures up to 30,000 p.s.i. at the point of first flame at the wellhead instantaneously after the flame appears. A further advantage of the invention is its provision of a means for operating a blowout preventer with the high pressure carbon dioxide-fire retardant mixture simultaneously with the blanketing of the fire at the well-head. Further, it replaces the hazardous and expensive use of high explosives, and in contrast to the latter does not always destroy the well. An advantageous alternate use of the invention is the elimination of the manifold 10 from the drilling fluid line after drilling has stopped and pumping begun and the use of the manifold type standby fire retardant tank 20 equipped with carbon dioxide surge boosters installed in a manner similar to that by which they are installed in the manifold 10.

What is claimed is:

l. The method of extinguishing fires which comprises:

a. instantaneously vaporizing all of a non-gaseous inert product under conditions to produce a highly pressurized inert gas;

b. directing the highly pressurized inert gas into fire retardant material to mix it therewith with the resulting mixture being highly pressurized; and

c. directing said highly pressurized mixture into the fire.

2. The method of claim 1 in which said product is non-gaseous carbon dioxide and the highly pressurized gas is carbon dioxide.

3. The method of claim 1 in which the fire is an oil well fire and the highly pressurized gas is introduced into the drilling fluid conduit to mix it with the drilling fluid so that the drilling fluid serves as a fire retardant material.

4. The-method of claim 3 in which the highly pressurized gas is carbon dioxide.

5. The method of extinguishing fires which comprises;

a. containing non-gaseous carbon dioxide in a pressure container adapted to withstand pressures from about 8,000 p.s.i. to about 30,000 p.s.i.;

b. applying sufficient heat to said non-gaseous carbon dioxide to convert it to carbon dioxide gas and create pressures in the container up to 30,000 p.s.i. to release said carbon dioxide gas;

c. directing the highly pressurized escaping carbon dioxide gas into a container of fire retardant material at pressures from 8,000 p.s.i. to 30,000

p.s.i. to highly pressurized the resultant carbon dioxide fire retardant mixture; and

d. directing the resulting highly pressurized mixture onto the fire.

6. The method of claim in which the fire is an oil well fire and the high pressure carbon dioxide gas is introduced into the drilling fluid conduit wherein the drilling fluid serves as the fire retardant material.

7. The method of claim 5 including the step of using fire sensing means to actuate means for supplying heat to said non-gaseous carbon dioxide.

8. The method of claim 5 directed to pre enting fires and explosions in coal mines and including the step of positioning said container to direct the highly pressurized carbon dioxide-fire retardant mixture in the area where coal is being mined.

9. The method of extinguishing fires which comprises:

a. confining in a container under high pressure a nongaseous material which can be converted to a gas instantaneously upon heating;

b. raising the temperature of the material to its critical temperature instantaneously by heat to create a charge of highly compressed gas within the container; and

c. directing said high pressure gas into the fire.

10. The method of claim 9, in which said material is non-gaseous carbon dioxide.

11. The method of claim 9, in which said high pressure gas after being formed is directed into a fire retardant material to form a highly pressurized mixture of carbon dioxide and fire retardant material and the formed mixture is directed into the fire.

12. The method of claim 1 l, in which the material is non-gaseous carbon dioxide.

Claims

1. The method of extinguishing fires which comprises: a. instantaneously vaporizing all of a non-gaseous inert product under conditions to produce a highly pressurizEd inert gas; b. directing the highly pressurized inert gas into fire retardant material to mix it therewith with the resulting mixture being highly pressurized; and c. directing said highly pressurized mixture into the fire.

4. The method of claim 3 in which the highly pressurized gas is carbon dioxide.

5. The method of extinguishing fires which comprises; a. containing non-gaseous carbon dioxide in a pressure container adapted to withstand pressures from about 8,000 p.s.i. to about 30,000 p.s.i.; b. applying sufficient heat to said non-gaseous carbon dioxide to convert it to carbon dioxide gas and create pressures in the container up to 30,000 p.s.i. to release said carbon dioxide gas; c. directing the highly pressurized escaping carbon dioxide gas into a container of fire retardant material at pressures from 8,000 p.s.i. to 30,000 p.s.i. to highly pressurized the resultant carbon dioxide fire retardant mixture; and d. directing the resulting highly pressurized mixture onto the fire.

6. The method of claim 5 in which the fire is an oil well fire and the high pressure carbon dioxide gas is introduced into the drilling fluid conduit wherein the drilling fluid serves as the fire retardant material.

8. The method of claim 5 directed to preventing fires and explosions in coal mines and including the step of positioning said container to direct the highly pressurized carbon dioxide-fire retardant mixture in the area where coal is being mined.

9. The method of extinguishing fires which comprises: a. confining in a container under high pressure a non-gaseous material which can be converted to a gas instantaneously upon heating; b. raising the temperature of the material to its critical temperature instantaneously by heat to create a charge of highly compressed gas within the container; and c. directing said high pressure gas into the fire.

12. The method of claim 11, in which the material is non-gaseous carbon dioxide.