US2539452A

US2539452A - Fire extinguishing system

Info

Publication number: US2539452A
Application number: US537494A
Authority: US
Inventors: Mapes Daniel
Original assignee: Specialties Development Corp
Current assignee: Specialties Development Corp
Priority date: 1944-05-26
Filing date: 1944-05-26
Publication date: 1951-01-30
Anticipated expiration: 1968-01-30

Description

Jan. 30, 1951 D. MAPEs 2,539,452

FIRE EXTINGUISHING SYSTEM Filed May 26, 1944 2 Sheets-Sheet l 31 lg INYEI %K%d at W ATT RNEY Jan. 30, 1951 D. MAPES 2,539,452

FIRE EXTINGUISHING SYSTEM Filed May 26, 1944 2 Sheets-Sheet 2 L zw%z u A ORNEY Patented Jan. 30, 1951 FIRE EXTINGUISHING SYSTEM Daniel Manes, West Caldwell, N. l, assignor to Specialties Development Corporation, Bloomfield, N. 3., a corporation of New Jersey Application May 26, 1944, Serial No. 537,494

9 Claims.

My invention relates to fire extinguishing and more particularly to a system for extinguishing fires occurring in enclosures and the like. I

My invention is particularly concerned with extinguishing fires in enclosures such as cargo holds, storage spaces, tanks, rooms or compartments, and the casings or ho' sings of electrical equipment or internal combustion motors. Usually, an inert fire extinguishing m dium such as carbon dioxide, nitrogen, or mixtures thereof, or any suitable fluid pressure fire extinguishing medium is introduced into the enclosure to establish an inert atmosphere in which combustion cannot take place.

Heretofore it has been customary to extinguish fires in such enclosures by introducing a predetermined quantity of the medium. Usually, the quantity was controlled by emptying a container of fire extinguishing medium of predetermined capacity into an enclosure of a given volume. This required using the entire contents of the container even if only a small portion thereof would have been sufiicient to extinguish the fire. In the event the fire reignited itself after the introduction of the'fire extinguishing medium into the enclosure, the second fire could not be extinguished unless a reserve supply of fire extinguishing medium was provided for. The requirement of a reserve su ply resulted in the increase in size and weight of the systems required to protect an enclosure or group of en"- closures and resulted in more complex connectib'ns and controls for operating the system.

My invention aims to provide a system for extinguishing fires in enclosures wherein. initially,

the fire extinguishing medium is introduced into the enclosure until an atmosphere of predetermined inertness has been established to extinguish the fire, and, thereafter, an additional uuaiitity of the medium is introduced into the enclosure in response to a decrease in the inertness of the atmosphere in the enclosure toprevent a reoccur'rence of the fire during a fire period, thereby conserving the fire extinguishing medium over a period during which the me may reoccur.

Accordingly, an object of my invention is to provide 'a fire extinguishing system which elimi- 'nat'e's the waste of fire extinguishing medium.

Another object is to provide a fire extinguishing system adapted to maintain an inert atmos- "phere in an enclosure for a considerable period "after the commencementof fire to prevent the 'r'eoccurrenee of a l fire during the fire period.

Another object isto provide a fire extinguish 2 ing system of the foregoing character wherein the release of additional fire extinguishing medium, after an initial discharge, is controlled by the inertness of the atmosphere in the enclosure protected.

Another object is to provide a system which is simple in construction and can effectively control fires in enclosures with a minimum amount of fire extinguishing medium.

A further object is to provide a, system for extinguishing fires which is reliable, effective and safe.

Other and further objects of the invention will be obvious unon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawings, forming a part of the specification, where- Figure 1 is a diagrammatic view of afire extinguishing system, illustrating an embodiment of my invention.

Figure 2 is a diagrammatic view of a control circuit used in connection with the system.

As illustrated in Figure l of the drawings, I provide a container '5 in which is stored any suitable inert fiuid pressure fire extinguishing medium, for instance, liquefied carbon dioxide. The container is provided with a control head 6 operable for releasing the medium to an enclosure 1 by means of a conduit 8 which has one end connected to the control head 6 and the other end equipped with a discharge head or horn 9 disposed within the enclosure 1. I,

While the enclosure is illustrated by way of example as a compartment, it will be understood that it is intended to represent diagrammatically any of the spaces or enclosures referred to herein.

The conduit 8 has incorporated therein a control device ill for controlling the introduction of the medium to the enclosure and which device comprises a normally open solenoid con-- trolled valve connected in an electric circuit controlled by an analyzer l3 for measuring the in 'ertness of the atmos here in the enclosure 1. This may be accomplished by testing the atmosphere to determine if it will support combustion,

or, for example, by measuring percentage of carbon dioxide in the atmosphere within the enclosure 1.

The latter may be accomplished by observing the thermal conductivity of the atmosphere. The value of the conductivity of a gas may be ascertained when compared with air, the observed or computed ratio thus established being deemed the factor of thermal conductivity of gas. The thermal conductivity factor of carbon dioxide gas is such that it lends itself to the thermal conductivity test in such a manner that the actual percentage of carbon dioxide present in the air of an enclosure can be substant ally directly observed and registered on a galvanometer by means of a Wheatstone bridge arrangement.

The procedure in and the apparatus used for making observations of the foregoing described character is well known in the art and a detailed description thereof is not deemed necessary, it be ng sufficient to disclose the analyzer l3 (Figure 2) as comprising an unba anced Wheatstone bridge M which has connected thereto wires i 5 and iii in a circuit with a source ll of a constant E. M. F., the wire 16, adjacent the source I I having incorporated therein a switch l8 operated to c osed posit on when the control head is actuated for releasing the fluid from the container.

One pair of the arms of the bridge are formed by the fixed resistances I3, whereas the other pair of the arms contain the resistance wires of thermal conductivity units 20 and 2|. A galvanometer 22 is connected across the bridge as an indicating instrument by means of

wires

23 and 24. The thermal conductivity unit 20 is bridged by a suitable resistance wire and it contains a com arison gas, whereas the thermal conductivity unit 2|, which is equipped with a similar resistance wire, has its inlet connected to a relatively small pipe 25 leading to the enclosure 1 whereby air from the enclosure is supplied for ana ysis. Alternat vely, the unit 2| could be located in the enclosure and connected electrically in the bridge circuit.

The outlet of the unit 2| is connected to a pipe 26 leading to a pump 21 or the like, the pump being operated in any suitable manner, for instance, by a pressure operated motor 28 connected to the conduit 8, between the control dev ce Ill and the control head 6, by a pipe 29 having a pressure re u ating va ve 3!] incorporated therein. A pipe 3| connects the motor 28 to the enclosure '1 whereby the pressure medium passing therethrough is introduced into the enclosure. The analyzed air after passing through the pump may be conducted by a pipe 52 to a suitable location where the air may be visually observed to determine, for example, the smokiness thereof.

The galvanometer 22 is empirically calibrated and is provided with a hand or pointer 32 adjacent a scale 33 reading from 0 to 100 to denote .bon dioxide is in the enclosure to therebyv efiect operation of the control device I 0 to shut off the flow of carbon diox de to the enclosure.

The brush 34 of the hand 32 is connected to one pole of the E. M. F. by a wire 36 connected to the wire l6 while the segment 35 is connected to a magnet 3'! of a relay 39 by means of a wire 43, and the magnet is connected to the other pole of the battery by means of a wire 43 connected to the wire l5. The relay 39 is provided with an armature in the form of a pivoted lever 44 which constitutes a switch element of a switch 45. The pivoted end of the lever 44 is connected to the wire 43 and the free end of the lever is adapted to engage a contact connected by a wire 46 to one terminal of the solenoid of the control device in, the other terminal of the solenoid be ing connected to the wire I6 by means of a wire 47. The lever 44 is held out of attracted position with the magnet 3'! by means of a spring 48.

When the carbon dioxide concentration exceeds 35%, the brush 34 will engage the segment 35 thereby energizing the magnet 31 and operating the switch into closed position to energize the solenoid of the control device It], whereby the normally open valve of the control device will be closed. 'When the percentage of carbon diox de in the enclosure is less than 35%, the brush 34 is out of engagement with the segment 35 and thus the magnet 37 is not energized. The switch 45 is then in open position and the so enoid of the control device Ill is not energized, thereby enabling the valve of the control device it. to open and admit carbon dioxide to the enclosure.

If desired, an alarm or signal 50 may be provided which is actuated when the carbon dioxide concentration falls below 35%. The alarm is connected in a circuit comprising a wire, connected to one side of thesource of E. M. F. I! and to the s gnal 53, a wire 6| connected to the signal and to an arcuate segment 53 position on the scale along the 0 to 35% zone. The brush 34 of the hand is adapted to engage the segment 53 and establish an electrical connection with the other side of the source of E. M. F. I! by way of the wires 36 and I6, and the switch l8. The alarm may be disconnected by opening a switch 5! in the wire 3!. It will be understood that, in practice, the brush and segment switch arrangement would be arranged to operate a relay which in turn would close the signal circuit.

The cont ol head 3 may be o erated manually or automaticallv in any suitable manner. For example, a solenoid 7i] mav be provided for this purpose which is connected in an electrical circuit ada ted to be closed upon o eration of a heat responsive switch element H located in the enclosure. The heat responsive element ll may be of the tvne disclosed in United States Patent No. 2,318,607.

In operation, the occurrence of a fire in the enclosure 1 may be detected visually or by any suitable alarm or for example by the heat responsive switch ll which automatically effects operation of the device ill for operating the discharge control head 6 adapted to release the carbon dioxide into the conduit 8 which conducts it past the normall open valve I3 and into the enclosure. The operation of the control head 6 effects closing of the switch l8 which puts the analyzer into operation. Carbon dioxide continues to be discharged into the enclosure until a desired or predetermined concentration of carbon dioxide is established whereupon the analyzer circuit is eiiective to cause the valve ill to be clo ed. a

The analyzer continues to test the carbon di oxide concentration during this period, and, in the event the concentration should drop below a predetermined value, the valve H] is reopened to permit an additional quantity of carbon dioxide to be introduced into the enclosure. The foregoing may be repeated until it has been definitely established that the fire has been completely extinguished and that reoccurrence thereof is not probable.

In order to more fully understand some of the practical aspects of my invention, the operation of the system will be described in connection with several different types of enclosures chosen by way of example. 7

As previously indicated, the enclosure l may be a compartment, hatch or storage space wherein is stored any material constituting a class A (ordinary combustible materials) or a class B (highly inflammable materials) type fire hazard. Should a fire occur due to negligence, spontaneous combustion or other causes, the system is operated as described above. Should the fire rekindle itself due to glowing embers or heat remaining in the material after the carbon dioxide concentration has dropped, additional carbon dioxide is introduced into the space. This may be repeated until the compartment can be entered and inspected to determine the cause of the fire and elfect the removal of the cause.

Another advantageous use of my invention is in connection with internal combust on m tors of aircraft, for example. Should a fire occur, it is extinguished by the initial discharge of carbon dioxide while thereafter maintaining a carbon dioxide concentration in the engine nacelle to prevent or extinguish further fires. This particularly advantageous because it permits the engine to be kept in operation until an emergency landing can be made. Also, in connection with multi-motored aircraft it is desirable to maintain a faulty engine partly in operation instead of cutting it out completely. For example, even if the fire-plagued engine can be operated at a very low speed to permit the propeller to rotate, the air resistance to the craft is materiallv decreased and the remaining engines are not subjected to excessive strains.

My invention also may be utilized in connection with electrical fires (class C) which, for example, may occur in motors or generators due to faulty or worn out insulation. In the event a fire occurs, the system is operated to extinguish the fire and thereafter is operated intermittently to maintain an inert atmo phere in the casing or housing to prevent or extinguish further fires.

This enables the equipment to be used at least until there is an opportunity to shut down the equipment and repair the same. I

From the foregoing, it will be apparent that my invention provides an apparatus whereby a fluid medium, for instance, carbon dioxide, may be introduced into an enclosure and maintained therein over an appreciable period of time and with a substantially uniform qxmcentration value during such time. While I have described my invention in connection with the utilization of carbon dioxide, it is to be distinctly understood that any other suitable fluid medium may be employed for a like or similar purpose.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

It is also to be understood that the following cIaimsare intended to cover all the generic and specific features of the invention herein described, and all statements of the scope of the invention, which, as a matter of language, might be said to fall therebetween.

I claim:

1. In combination with an enclosure wherein the atmosphere normally is suificient to support combustion, a fire extinguishing system comprising a source of supply of fire extinguishing gas, means for con-ducting gas from said source into said enclosure upon the outbreak of fire therein in sufficient quantity to extinguish the fire, means rendered effective upon the outbreak of fire in said enclosure and operable thereafter for determining the concentration of the fire extinguishing gas in the enclosure, and means controlled by said determining means for maintaining a concentration of the fire extinguishing gas in said enclosure sufficient to prevent recurrence of the fire.

2. In combination with an enclosure wherein the atmosphere normally is sufficient to support combustion, a fire extinguishing system comprising a source of supply of fire extinguishing gas, means responsive to the outbreak of fire in the enclosure, means for releasing the gas from said source actuated upon operation of said responsive means, means for conducting the released gas from said source into said enclosure in sufiicient quantity to extinguish the fire, means operable thereafter for analyzing the atmosphere in the enclosure, means operable upon the operation of said releasing means to render said analyzing means efiective, and means controlled by said analyzing means for alternately discontinuing and'resin. ng the flow of the gas from said source into said enclosure when the analysis of the atmosphere therein indicates a fire extinguishing gas concentration sufiicient and insufficient, re-

spectively, to prevent recurrence of the fire.

'maintaining an atmosphere therein incapable of supporting combustion, the combination of a container for supplying a fire extinguishing gas, conduit means for conveying the gas from the container into the enclosure, release means for releasing the gas from the container to said conduit means, an analyzer for ascertaining the concentration of the gas in the enclosure when mixed with air therein, means operable upon operation of said release means to render said analyzer effective, and control means in said conduit means operable by said analyzer to control the admission of gas into the enclosure after extinguishment of the fire to maintain a mixture of air and gas therein incapable of supporting combustion.

4. In an automatic system for extinguishing fire in an enclosed space subject to asupply of outside air, and thereafter maintaining an atmosphere therein incapable of supporting combustion, the combination of a source of supply of fire extinguishing medium under pressure for mixture with air in the enclosed space to render the mixture incapable of supporting combustion, means for releasing medium from said source, fire responsive means in the enclosure for actuating said releasing means upon the outbreak of fire in the enclosure, means for conducting "the released medium from the supply source into the space to extinguish the fire, said last means including a normally open valve, means for'an- 7 alyzing the mixture, means operable upon the operation of said releasing means to render said analyzing means efiective, and means controlled by said analyzing means for closing and opening said valve in response to the analyzing means alternately to prevent and to cause flow of the medium into the space whereby to maintain the mixture incapable of supporting combustion.

5. In combination with an enclosure wherein the atmosphere normally is sufiicient to support combustion, a fire extinguishing system comprising a source of fire extinguishing gas, means for conducting the gas from said source into the enclosure, a valve in said conducting means, means for withdrawing samples of the atmosphere within the enclosure including a conduit, means associated with said conduit for analyzing the samples and for controlling said valve, and gas operated motor means for operating said sampling means including a conduit connected to said conducting means.

6. In combination with an enclosure wherein the atmosphere normally is sufficient to support combustion, a fire extinguishing system comprising a source of fire extinguishing gas, means for conducting the gas from said source into the enclosure, a valve in said conducting means, a conduit having one end extending into said enclosure, suction means connected to said conduit for withdrawing samples of the atmosphere within the enclosure, means associated with said conduit for analyzing the samples and controlling the valve, a pipe connected to said conducting means between said valve and said source, and gas operated motor means connected to said pipe for operating said suction means.

'7. In combination with an enclosure wherein the atmosphere normally is sufiicient to support combustion, a fire extinguishing system comprising a source of fire extinguishing gas, means for conducting the gas from said source into the enclosure, a valve in said conducting means, a conduit having one end extending into said enclosure, suction means connected to said conduit for withdrawing samples of the atmosphere within the enclosure, means associated with said conduit for analyzing the samples and controlling the valve, a pipe having one end connected to said conducting means between said valve and said source and having its other end extending into the enclosure, and gas operated motor means having an inlet and an outlet connected to said pipe for operating said suction means.

8. In combination with an enclosure wherein the atmosphere normally is sufficient to support 8 I combustion, a fire extinguishing system comprising a source of fire extinguishing gas, means for conducting the gas from said source into the enclosure, a valve in said conducting means, a conduit having one end extending into said enclosure, suction means connected to said conduit for withdrawing samples of the atmosphere within the enclosure, means associated with said conduit for analyzing the samples and controlling the valve, a pipe having one end connected to said conducting means between said Valve and said source and having its other end extending into the enclosure, gas operated motor means having an inlet and an outlet connected to said pipe for operating said suction means, and flow restricting means in said pipe between said conducting means and said motor means.

9. In combination with an enclosure wherein the atmosphere normally is sufiicient to support combustion, a fire extinguishing system comprising a source of fire extinguishing gas having means for releasing the gas therefrom, means for conducting the gas from said source into the enclosure, a valve in said conducting means, a conduit having one end extending into said enclosure, suction means connected to said conduit for withdrawing samples of the atmosphere within the enclosure, means associated with said conduit for analyzing the samples and controlling the valve, means operable by said releasing means to render said analyzing means effective, a pipe having one end connected to said conducting means between said valve and said source and having its other end extending into the enclosure, gas operated motor means having an inlet and an outlet connected to said pipe for operating said suction means, and flow restricting means in said pipe between said conducting means and said motor means.

DANIEL MAPES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 7,269 Phillips Apr. 9, 1850 910,036 Wolfson Jan. 19, 1909 1,244,427 Coppus Oct. 23, 1917 1,993,695 Allen et a1. Mar. 5, 1935 2,025,782 Seat Dec. 31, 1935 2,265,810 Lowe et a1. Dec. 9, 1941 2,353,538 Barber July 11, 1944