US2525570A

US2525570A - Fire-extinguishing apparatus and method

Info

Publication number: US2525570A
Application number: US626309A
Authority: US
Inventors: Hilding V Williamson
Original assignee: Cardox Corp
Current assignee: Cardox Corp
Priority date: 1945-11-02
Filing date: 1945-11-02
Publication date: 1950-10-10
Anticipated expiration: 1967-10-10

Description

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m m 1 M a 1. M 5 m 2 S V w 5 .r m. 2 V a Z 2 1950 H. v. WILLIAMSON FIRE EXTINGUISHING APPARATUS AND HETHOD Filed Nov 2, 1945 H. V. WILLIAMSON FIRE EXTINGUISHING APPARATUS AND METHOD 2 Sheets-Sheet 2 INVENTOR.

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Oct. 10, 1950' Filed Nov. 2, 1945 Patented Oct. 10, 195),

FIRE-EXTINGUISHING APPARATUS AND METHOD Hilding V. Williamson, Chicago, Ill., assignor to Cardox Corporation, Chicago, Ill., a corporation of Illinois Application November 2, 1945, Serial No. 626,309 Claims. (Cl. 62-1) This invention relates to anapparatus for and a method of extinguishing fires or protecting fire hazards to reduce fire damage. In particular, the invention is concerned with the storage of low pressure refrigerated carbon dioxide to make it more available for extinguishing fires.

The use of low pressure refrigerated carbon dioxide for extinguishing fires has had recent extensive development. This has involved storage of liquid carbon dioxide in closed tanks so that it will be available upon demand. Storage of the liquid carbon dioxide in mobile fire fighting apparatus has had especial widespread development so that the extinguishing medium could be brought to a fire hazard orto a fire.

A general method of storing and handling low pressure refrigerated carbon dioxide is disclosed and claimed in Patent 2,180,231, issuedto Eric Geertz et al., on November 14, 1939. In Patent 2,352,379, issued to Eric Geertz,on June 2'1, 1944, a mobile fire fighting apparatus is described and claimed. The present invention utilizes the general principles of the disclosures of these patents, but provides a mobile fire fighting unit having a minimum amount of auxiliary equipment.

In the storage of low pressure refrigerated carbon dioxide each storage tank has been, in the past, insulated and equipped with the required safety and relief valves and filling and discharge outlets. In addition, each storage tank has been equipped with refrigeration apparatus for maintaining the carbon dioxide at a sub-atmospheric temperature, a liquid level device for indicating the amount of carbon dioxide in the tank, and a pressure gauge for indicatingthe pressure of the carbon dioxide in the tank.

In large storage tanks, either fixed or located 1 on mobile fire fighting apparatus, the weight of and space occupied by the refrigeration apparatus, liquid level device, and pressure gauge are small compared to the total weight of and space occupied by the tank unit. However, in small mobile fire fightin apparatus having small storage tanks, the weight of and space occupied by the refrigeration apparatus, liquid level device, and pressure gauge become an appreciable fraction of the total. In the mobile fire fighting apparatus, additional vehicle capacity must be provided for by additional weight and space so that any savings in either weight or space materially reduces the overall size of the vehicle. The present invention provides mobile fire fighting apparatus having a reduced weight and size. Also, these small, light weight mobile units are relatively inexpensive to construct.

Wherever mobile fire fighting apparatus using liquid carbon dioxide is maintained, it is highly desirable that a stationary storage tank of carbon dioxide also be provided, so that in the event of the use of carbon dioxide from the mobile fire fighting unit, it can be immediately replaced from the stationary storage unit to maintain the mobile fire fighting unit in readiness for further use. In accordance with the present invention, a large stationary primary supply tank is emplyoyed and is provided with the usual auxiliary equipment as refrigerating apparatus; pressure gauge and level gauge. Also, small mobile secondary tanks are employedbut they arenot provided with refrigerating apparatus, pressure gauge or level gauge. This latter auxiliary equipment may be dispensed with on the mobile tanks since during standby conditions they are connected to thelprimary tank and are thereby maintained withcarbon dioxide at the proper temperature, pressure and level conditions.

When a hazard is to be protected, or a fire is to be extinguished, the secondary tanks may be disconnected from the primary tanks and moved to the desired location. i i i The manner inwhich these advantages are obtained, and other features of the present invention, will be apparent from thefollowing description and the accompanying drawings.

In the drawings: 1 f 1 Figure 1 is a front elevational view of the equipment of one embodiment of the invention,

Figure 2 is a plan view of Figure 1, and

Figure 3 is a side elevational view of one of the mobile secondary tanks.

The primary storage tank 5 is enclosed within insulation 6 and an outer protecting shell or housing I. Operatively associated with this tank 5 is a refrigerating apparatus, the details of which are not shown as any suitable" equipment may be used. As illustrated, the refrigerating unit consists of a housing 8 in which is located a conventional compressor-condenser unit 8' and an electric motor 8" for driving the compressor.

. The refrigerating cycle is completed by the evaporator coil 9 thatis positioned in the vapor space of the primary storage tank 5 and functions to condense the carbon dioxide vaporin said space to maintain the desired sub-atmospheric temperature and pressure condition within said tank. 1

If desired, more than one primary storage tank may be employed in order to accommodate the necessary quantity of liquid carbon dioxide. The volumetric capacity of the tank to be utilized and the number of them which should be employed will depend upon the extent of and the probable frequency of a fire at the hazard to be protected.

The tank 5 should also be equipped with a liquid level gauge of any suitable type, as for example, the visual one represented at III. A pressure release valve, indicated at II, should be in open communication with the interior of the tank to permit the escape of vapor if it rises to an excessive pressure. A pressure gauge l2 should also be provided to show the pressure of the vapor within the tank. Suitable controls, as for example, an automatic device to regulate the operation of the refrigerating unit will be provided.

The tank 5 may be replenished through the valved pipe l3. This supply to tank 5 ordinarily will'be from a transportation truck or\railway car which receives its charge from a processing source of liquid carbon dioxide.

The insulated primary storage tank 5 is elevated at a height above the ground level at It, in any suitable manner. As here shown, the tank 5 is supported upon a trussed framework II, but it is to be understood that any elevated platform or embankment may be utilized to carry the tank at an elevated position above an adjacent ground level.

Leading from the lower end of tank 5 is a liquid header l8 having a valve I9 therein as it emerges from the housing 1. Connected to this header It at spaced points along its length are branch pipes 20. As here shown. the header I8 is broken off to indicate that it may be of any desired length to accommodate a large number of branch pipes 20, but it is to be understood that the far end of this header l8 will be closed.

A vapor header 2! enters the upper side of tank 5 to communicate with the vapor space therein. A valve 22 is in thi header close to the tank. The vapor header extends generally alongside of or parallel to the liquid header It and from it descend branch pipes 23. The branch pipes are located along header 2| at points corresponding to the spacing of branch pipes 20 so that there will be a pair of these branch pioes at desired intervals. Header 2| should be closed at its distant end. Suitable su porting means, not shown, will be provided for the headers l8 and 2|.

It is intended that each pair of

branch pines

20 and 23 be connectable to mobile secondary tanks to maintain t em filled to the desired level with refrigerated liquid carbon dioxide. It is also intended that such secondary tanks be disconnectable at will from the

branch pipes

20 and 23 so that these tanks can be moved to the location of a fire or a fire hazard. One suitable mobile secondary tank is that indicated at 25 and which is mounted upon a wheel cart or trailer 26. The front wheels preferably are steerable as by the use of caster or guidable front wheels, and the tank 25 may be pulled or drawn about by using the handle or draft bar 21. The trailer 26 may be moved manually or by a power driven machine, as a truck or a tractor.

Another type of mobile secondary tank is that indicated at 28 as being mounted upon a truck 29. The truck may be any appropriate kind of self-propelled vehicle. It is to be understood that the vehicles 2-5 and 29 are only examples of the mobile supports which may be employed to mount the secondary tanks and that other mobile tanks ma be employed. Thus, the invention eomprehends the use of portable 56G- ondary tanks which will be carried by one or more persons to the place of use.

It is intended that the secondary tanks be well insulated, as shown at 3| for tank 25, and at 32 for tank 28. Each of the

tanks

25 and 28 has a valve controlled dip tube 33 for the delivery of liquid carbon dioxide from the tank. For example, a flexible pipe having a nozzle at its end may be permanently connected to tube 33 beyond the valve therein.

Extending from each tank is a pipe 34 for connection to liquid branch pipe 20, and also extending from each tank is a pipe 35 for connection to vapor branch pipe 23. Each secondary tank should also be equipped with a, safety relief valve 36 and in accordance with the invention, this may be the only auxiliary equipment associated with these mobile tanks.

Thus, it is not necessary to provide the

secondary tanks

25 and 28 with refrigerating apparatus, a pressure gauge, or a liquid level gauge. When the secondary tanks are connected to the primary tank 5, refrigerated liquid will flow by gravity along header l3 and into the auxiliary tanks through

branch pipes

23 and 34. The vapor which forms in the

secondary tanks

25 and 23, due to heat absorption through the surrounding insulation, is returned to the primary tank through

branch pipes

35 and 23, and vapor header 2 I. Since the secondary tanks are supplied with refrigerated liquid carbon dioxide in this manher from the primary tank 5, it is not necessary for them to have their own refrigerating apparatus. As long as they remain connected to the primary tank as a closed circuit or system, the secondary tanks make use of the refrigerating apparatus at 3 to be maintained supplied with liquid carbon dioxide at the proper low temperature.

A liquid level gauge is not necessary for the

secondary tanks

25 and 23, as the level cannot rise substantially above the lower end of the vapor pipe 35. This is due to the fact that the closing of the open ends of the vapor pipes 35 prevents the escape of vapor from

tanks

25 and 23. Consequently, the admission of additional liquid carbon dioxide to tanks 25 and 2| will cause a rise in vapor pressure therein. As liquid carbon dioxide is delivered only by gravity from the primary tank 5 its flow will be stopped by the rise in pressure that occurs in

tanks

25 and 23. Thus, there must always be vapor above the lower end of pipe 35 and this vapor will serve as a cushion for any expansion or contraction of the liquid carbon dioxide.

When the

secondary tanks

25 and 25 are connected to the primary tank 5, the pressure in them will be the same as that in the primary tank and pressure gauges are not necessary for the secondary tanks. When the secondary tanks are detached from the primary tank, their relief valves 36 serve to prevent an increase in vapor pressure beyond a safe limit and therefore a pressure gauge is not necessary. This escape of vapor through valves 35 when the secondary tanks are separated from the primary tank, serves to maintain the liquid carbon dioxide at a refrigerated temperature due to the self-cooling action resulting from vaporization of additional liquid.

It is intended that the connection at 33' between

branch pipes

20 and 35, and the connection at 33 between

branch pipes

23 and 35 be established by quick-detachable, self-closing couplings. While any coupling of this character may be employed, it is, preferred that the one disclosed and claimed in application Serial No. 626,308, filed November 2, 1945, by H. V. Williamson and R. Harry Griesemer, now Patent 2,453,480, be em ployed, and -it is intended that that coupling be considered as a part of the present disclosure. A coupling of this type is desirable because it permits a quick breakin the piping to the

secondary tanks

25 and 28, and automatically results in the closure of these ends so that carbon dioxide cannot escape. However, it is possible to employ any coupling or union at 38 and 39 and if they are not of the valved self-closing type,

branch pipes

20, 23, 34 and .35 should each be provided with its own manual shut-ofi valve.

As the liquid carbon dioxide flows by gravity from the stationary primary tank 5 into the mobile

secondary tanks

25 and 28, the primary tank must be elevated to at least a height such that the liquid level in the primary tank will be above the liquid level in the secondary tanks. In order that the primary tank may be emptied in supplying the secondary tanks, it is preferred that the bottom of the primar tank 5 'be higher than the top of the secondary tanks, and this also requires that the liquid header ll be not higher than the bottom of the primary tank 5.

The pipe lines and couplings should all be well insulated to reduce loss of refrigeration. This is particularly important because the liquid carbon dioxide and the cool vapor are constantly in the headers l8 and 2| and in the

branch pipes

20, 23, 34 and 35 during the times that the secondary,

tanks

25 and 28 are both coupled to and uncoupled from the primary tank 5.

The equipment may be employed in a variety of ways. In some instances, the mobile

secondary tanks

25 and 28 may remain coupled to the primary tank 5 until the moment that a fire occurs, at which time the secondary tanks will be uncoupled and transported to the location of the fire. In this practice, the secondary tanks remain on line during the standby periods as they are coupled into the closed circuit including the primary tank 5. When the fire is extinguished, or the secondary tank is exhausted, it is returned to the primary tank 5 and coupled thereto for replenishment. I

In other instances, the mobile

secondary tanks

25 and 28 may be disconnected from the primary tank 5 during a period of possible fire and be brought to the hazard so that the extinguishing medium will be instantly available. For example, at airports, the mobile secondary tanks may be used as crash trucks and during the reduced activity of nighttime they may be coupled to the primary supply tank 5 for filling. During the daytime, the mobile tanks may be distributed around the airfield, because of the increased daytime activity. While the mobile tanks are so distributed about and separated from the primary tank, they will maintain themselves refrigerated by the relief of vapor escaping past valves 38.

In factories or warehouses, the mobile

secondary tanks

25 and 28 may remain connected to the primary tank 5 until a fire occurs, or they may be brought to a fire hazard to be in readiness to extinguish a fire in the event it occurs to reduce the damage to aminimum. As the hazard may be at different places at different times, as for example, combustible material may be stored at diflerent places on difierent days in a warehouse,

the use of the mobile secondary tanks makes it possible to always place them at the locations of these hazards.

What I claim is:

1. Apparatus for extinguishing fires comprising an insulated primary storage tank to contain refrigerated liquid carbon dioxide, means supporting the primary tank in a stationary elevated position, an insulated secondary tank which is portable for transportation to a fire, normally open conduit means for connecting the secondary tank to the primary tank so that the secondary tank will be gravitationally replenished with refrigerated liquid carbon dioxide during standby periods, means for refrigerating the carbon dioxide in the primary tank to maintain the liquid carbon dioxide in the primary and secondary tanks at abalanced constant low temperature and its corresponding low vapor pressure condition, disconnectable coupling means of the valved self-closing type in said conduit means to permit separation of the secondary tank from the primary tank without loss of carbon dioxide from either, and a relief valve for the secondary tank to vent excess vapor pressure therefrom while disconnected from the primary tank.

2. Apparatus for extinguishing fires comprising an insulated primary storage tank to contain refrigerated liquid carbon dioxide, refrigerating means for cooling the liquid carbon dioxide in the tank to a low temperature and its corresponding low vapor pressure, at least one secondary tank to be replenished with liquid carbon dioxide from theprimary storage tank, the secondary tank being portable so that it may, be moved to a fire hazard, a support for mounting the primary storage tank at a level above the secondary tank, a normally open conduit leading from a lower portion of the primary storage tank into the secondary tank for liquid carbon dioxide to gravitate into the secondary tank, another normally open conduit'joining the upper portions. of the storage and secondary tanks for the free flow of vapor between the secondary and primary tanks, and means associated with said last mentioned conduit for maintainin a vapor space of predetermined depth in the secondary tank.

3. The method of maintaining a fire cxtinguishing medium in readiness for use, comprising confining a supply of liquid carbon dioxide in an elevated stationary storage space, confining a, lesser supply of liquid carbon dioxide in a chamber that is transportable between the location of the stationary storage space and the locations of fires so that the carbon dioxide in the transported chamber can be discharged to effect extinguishment of the fires, during the standby carbon dioxide in the transportable chamber during standby periods at a balanced preselected sub-atmospheric temperature and its corresponding vapor pressure condition by only refrigerating the carbon dioxide in the stationary storage space.-

4. The method of maintaining a fire extine guishing medium in readiness for use, comprising confining a supply of liquid carbon dioxide in an elevated stationary storage space, confinin atom-2o transported chamber can be discharged to eiiect extinguishment or the fires, during standby periods for the transportable chamber replenishing the supply of liquid carbon dioxide therein by gravitational flow from the stationary stor-- age space of only sufilcient liquid carbon dioxide to at all times maintain a liquid level in said chamber which will-provide a constant vapor space of desired-volume and flowing carbon dioxide vapor between the transportable chamher and the stationary storage space to at all times balance the vapor pressures in said chamber and space, and maintaining the carbon dioxide in the stationary storage space at all times and the carbon dioxide in the transportable chamber during standby periods at a balanced preselected sub-atmospherlc temperature and its corresponding vapor pressure condition by only condensing the carbon dioxide vapor in the stationary storage space.

5. The method of maintaining a fire extinguishing medium in readiness for use, comprising confining a supply of liquid carbon dioxide in an elevated stationary storage space, confining a lesser supply of liquid carbon dioxide in a chamber that is transportable between the location of the stationary storage space and the locations of fires so that the carbon dioxide in the transported chamber can be discharged to effect extinguishment of the fires, during standby periods for the transportable chamber replenishing and maintaining the supply of liquid carbon dioxide therein by gravitational fiow from the stationary storage space and flowing carbon dioxide vapor between the transportable chamher and the stationary storage space to at all times balance the vapor pressures in said chamber and space, and maintaining the carbon dioxide in the stationary storage space at all times and the carbon dioxide in the transportable chamber during standby periods at a balanced preselected sub-atmospheric temperature and its corresponding vapor pressure condition by only condensing the carbon dioxide vapor in the stationary storage space, and maintaining the carbon dioxide in the transportable chamber at said preselected sub-atmospheric temperature and its corresponding vapor pressure during periods when the chamber is disconnected from the stationary storage space by the self-refrigerating action resulting from the venting of vapor from the chamber to the atmosphere;

6. The method 01 maintaining a fire extinguishing medim in readiness' for use, comprising confining a relatively large supply of liquid carbon dioxide in an elevated stationary storage space, confining a lesser supply of liquid carbon dioxide in each one of a plurality of chambers that are independently transportable between the location oi the stationary storage space and the locations oi fires so that the carbon dioxide in the transported chambers can be discharged to efiect extinguishment of the fires, during the standby periods for all of the transportable chambers, replenishing and maintaining the supply of liquid carbon dioxide therein by gravitational fiow from the stationary storage space and flowing carbon dioxide vapor between the transportable chambers and the stationary storage space at all times balance the vapor pressures in said chambers and space, and maintaining the carbon dioxide in the stationary storage space at all times and the carbon dioxide in the transportable chambers during standby periods at a balanced preselected sub-atmospheric temperature and its corresponding vapor pressure condition by only refrigerating the carbon dioxide in the stationary storage space.

'7. Apparatus for extinguishing fires, comprising an insulated primary storage tank for liquid carbon dioxide, means for supporting the primary tank in a stationary elevated position, a liquid header connected to the liquid space of the primary tank and extending horizontally therefrom at a level that will permit gravitational fiow of liquid carbon dioxide therethrough, at least one valved branch pipe extending from the liquid header for connection to a separate portable secondary tank which is to be supplied with carbon dioxide by gravitational flow from the primary tank, a vapor header connected to the vapor space or the primary tank and extending generally in horizontal parallelism with the liquid header, at least one valved branch pipe extending from the vapor header for connection to the same separate portable secondary tank for delivering carbon dioxide vapor from said secondary tank to the primary tank during filling 'periods for the secondary tank and whenever the vapor pressure in the secondary tank rises above that of the primary tank while they are connected, means for automatically stopping the gravitational flow of liquid carbon dioxide to the secondary tank at the liquid level desired therein. and a refrigerating unit connected to the primary tahk and having a refrigerating capacity that will maintain the liquid carbon dioxide stored therein at a preselected sub-atmospheric temperature andits corresponding vapor pressure regardless of the amount of carbon dioxide .vapor that is delivered thereto from said connected secondary tank.

8. Apparatus for extinguishing fires, comprising an insulated primary storage tank for liquid carbon dioxide, means for supporting the primary tank in a stationary elevated position, a liquid header connected to the liquid space oi the primary tank and extending horizontally therefrom at a level that will permit gravitational fiow of liquid carbon dioxide therethrough, at least one valved branch pipe. depending from the liquid header, a vapor header connected to the vapor space of the primary tank and extending in horizontal parallelism with the liquid header, at least one valved branch pipe depending from the vapor header adjacent the branch pipe for the liquid header, an insulated secondary tank that is transportable between the location 0! said primary tank and fire hazards to be protected, said secondary tank having separate valved liquid and vapor pipes for connection with the said branch pipes of the liquid and vapor headers so that the secondary tank can be replenished with liquid carbon dioxide by gravitational fiow from the primary tank and so that carbomdioxide vapor can fiow from the secondary tank to the primary tank during such replenishing and whenever the vapor pressure in the secondary tank rises above that of the primary tank while they are con-V nected, means for automatically stopping the gravitational flow of liquid carbon dioxide to the secondary tank at the liquidlevel desired therein, and a refrigerating unit operatively connected to the primary tank and having a refrigerating capacity that will maintain the liquid carbon dioxide stored in both the primary and the secondary tanks, when they are connected, at a preselected sub-atmospheric temperature and its corresponding vapor pressure.

9. Apparatus for extinguishing fires, comprising an insulated primary storage tank for liquid carbon dioxide, means for supporting the primary tank in a stationary elevated position, a liquid header connected to the liquid space of the primary tank and extending horizontally therefrom at a level that will permit gravitational flow of liquid carbon dioxide therethrough, at least one valved branch pipe depending from the liquid header, a vapor header connected to the vapor space of the primary tank and extending in horizontal parallelism with the liquid header, at least one valved branch pipe depending from the vapor header adjacent the branch pipe for the liquid header, an insulated secondary tank that is transportable between the location of said primary tank and the locations of the fire hazards that are to be protected, said secondary tank having separate valved liquid and vapor pipes for connection with the said branch pipes of the liquid and vapor headers so that the secondary tank can be replenished with liquid carbon dioxide by gravitational flow from the primary tank and so that carbon dioxide vapor can flow from the secondary tank to the primary tank during such replenishing and whenever the vapor pressure in the secondary tank rises above that of the primary tank while they are connected, the inner end of the valved vapor pipe for the secondary tank terminating at a location in the upper portion of the secondary tank which, when said pipe end is closed by the rising liquid level, will automatically stop the replenishing of the seondary tank at the liquid level desired therein, and a refrigerating unit operatively connected to the primary tank and having a refrigerating capacity that will maintain the liquid carbon dioxide stored in both the primary and the secondary tanks, when they are connected, at a preselected sub-atmospheric temperature and its corresponding vapor pressure.

10. Apparatus for extinguishing fires, comprisir an insulated primary storage tank for liquid carbon dioxide, means for supporting the primary tank in a stationary elevated position, a liquid 10 header connected to the liquid space of the primary tank and extending horizontally therefrom at a level that will permit gravitational flow of liquid carbon dioxide therethrough, a plurality of spaced valve branch lines depending from the liquid header, a. vapor header connected to the vapor space of the primary tank and extending in horizontal parallelism with the liquid header, a plurality of correspondingly spaced valved branch pipes depending from the vapor header and located adjacent the respective branch pipes for the liquid header, a plurality of insulated secondary tanks that are transportable between the location of said primary tank and the locations of the fire hazards that are to be protected, said secondary tanks each having separate valved liquid and vapor pipes for connection with a pair of adjacent branch pipes of the liquid and vapor headers so that the secondary tanks can be replenished with liquid carbon-dioxide by gravitational flow from the primary tank and so that carbon dioxide vapor can flow from the secondary tanks to the primary tank during such replenishing and whenever the vapor pressures in the secondary tanks rise above that of the primary tank while they are connected, and a refrigerating unit operatively connected to the primary tank and having a refrigerating capacity that will maintain the liquid carbon dioxide stored in the primary tank and in all of the secondary tanks that are connected to the primary tank at a preselected sub-atmospheric temperature and its corresponding vapor pressure.

HILDING V. WILLIAMSON.

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

UNITED STATES PATENTS Number Name Date 2,090,163 Twomey Aug. 1'7, 1937 2,121,675 White June 21, 1938 2,180,231 Geertz et al Nov. 14, 1939 2,321,445 Yendall et a1 June 8, 1943 2,322,449 Johnson et a1 June :22, 1943 2,352,379 Geertz June 27, 1944 2,384,677 Hill Sept. 11, 1945