Abstract:
The invention provides an air delivery system for emergency workers, wherein the air delivery system is adapted to be used with a water hose. The system includes a source of compressed air fluidically connected to the water hose to purge water from the water hose. Pressure adjusting means adjust the compressed air pressure to less than approximately 300 psig. Means are provided for further reducing the air pressure, after the water is purged, to a pressure in the range of approximately 8-50 psig. The system further includes means for transferring air from the air hose to a breathing cavity of the worker.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to an air delivery system for use by emergency workers such as firemen who may be trapped inside a burning building. 
     DESCRIPTION OF THE PRIOR ART 
     Fires commonly produce toxic and lethal fumes in addition to smoke. Indeed, injuries and fatalities relating to these fires are often attributed to asphyxiation rather than burning. Therefore when firemen enter burning buildings, they generally carry on their backs a self-contained breathing apparatus such as a compressed air tank attached by a hose to a breathing mask. However, such tanks carry only approximately 30 minutes worth of air. In many fires, the floor or roof of a building may collapse, trapping a fireman. In such situations, the fireman has a high risk of suffocation because the time required to rescue the fireman may exceed the time available from the air tank. 
     Several prior art devices have attempted to address this problem. For example, U.S. Pat. No. 386,751 to Loomis discloses a device for supplying air to fireman in burning buildings in which the water hose carried by the fireman incorporates a separate air hose within it. The air and water is intended to be delivered simultaneously. U.S. Pat. No. 1,808,281 to Balthazor discloses a system wherein fresh air is drawn inwardly from the nozzle end of the hose by taking fresh air directly from the stream of water passing through the hose. Finally, U.S. Pat. No. 2,515,578 to Wilson discloses a system similar to that of Balthazor in that air is commingled with water flowing through the nozzle of the hose. 
     The references tabulated below disclose relatively complicated systems for providing fresh air to enclosed areas. None of these references pertain specifically to fire fighting situations. 
     
         ______________________________________                INVENTOR______________________________________U.S. PAT. NO.2,120,563              Lamb2,299,793              Cannaday, et al.4,165,738              Graves4,373,522              Zien4,440,164              Werjefelt4,467,796              BeagleyGREAT BRITAIN PATENT NO. 5,71,422______________________________________ 
    
     Nothing in the prior art discloses an effective, rapid system for delivering air to a trapped fireman through the water hose carried by the fireman. 
     SUMMARY OF THE INVENTION 
     Briefly described and in accordance with one embodiment of the invention, the invention provides an air delivery system for emergency workers, wherein the air delivery system is adapted to be used with a water hose. The system includes a source of compressed air fluidically connected to the water hose to purge water from the water hose. Pressure adjusting means adjust the compressed air pressure to less than approximately 300 psig. Means are provided for further reducing the air pressure, after the water is purged, to a pressure in the range of approximately 8-50 psig. The system further includes means for transferring air from the air hose to a breathing cavity of the worker. 
     It is an object of the present invention to provide a safe, rapid and effective system for delivering air to emergency workers detained in areas where the supply of breathable air is limited. 
     It is another object of the present invention to deliver air to trapped firemen through the water hose conventionally carried by such firemen. 
     It is another object of the present invention to provide an uncomplicated and inexpensive system for delivering emergency air to firemen detained in burning buildings. 
     Other objects, advantages and features of the present invention will become apparent from the following specification when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a fireman using conventional firefighting equipment, with elements of the present invention sketched in dashed lines for comparison. 
     FIG. 2 is a plan view of one embodiment of the emergency air delivery system of the present invention. 
     FIG. 3 is a closeup view of a pressure gauge and several valves of the embodiment illustrated in FIG. 1. 
     FIG. 4 is a closeup view of the air extractor of the present invention. 
     FIG. 5 is a sectional view taken on line 5--5 of FIG. 4. 
     FIG. 6 is a closeup view of the air inductor of the present invention. 
     FIG. 7 is a plan view of an alternate embodiment of the present invention. 
     FIG. 8 is a closeup view of the air shifter module of the alternate embodiment illustrated in FIG. 7. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a fireman using conventional firefighting equipment. At the scene of a fire, pumper truck 2 provides water to douse the fire. A first hose 4, approximately 15-50 feet long, is quickly attached to the water reservoir in the truck. When a fireman 6 is ready to enter the burning building, an attack line 8 approximately 150 feet long is attached to first hose 4. First hose 4 and attack line 8 are of similar construction and have the same diameter, typically, 11/2, 13/4, 2 or 21/2 inches. First hose 4 and attack line 8 typically have a maximum pressure rating of 300 psig. Water flowing through the hoses is directed at the fire by nozzle 9. 
     To protect himself from smoke and toxic fumes, fireman 6 invariably wears emergency breathing apparatus consisting of compressed air tank 10 connected by tank hose 12 to a regulator 14 which controls the flow rate and pressure of air into mask hose 16 leading to breathing mask 18. Tank 10 generally contains only approximately 30 minutes worth of air; regulator 14 is worn on belt 20, so that the fireman can turn air flow on and off as conditions require, in order to conserve the air supply. Fireman 6 also usually carries a two-way radio to communicate with firemen outside the building. 
     In FIG. 1, elements comprising the air delivery system of the present invention are shown by dashed lines to illustrate how the present invention is integrated into conventional firefighting equipment. Air extractor 22 is connected to attack line 8 immediately behind nozzle 9. Extractor 22 contains at least three quick-connect ports 23, each of which is adapted to connect to a mask hose 16. Extractor 22 will usually remain in place whether or not the air delivery system is being used. Air inductor 24 is attached to the hose line at the junction of first hose 4 and attack line 8. Extractor 22 and inductor 24 are constructed from aircraft aluminum pipe having a wall thickness of 1/2 inch; the extractor and inductor have diameters suitable for the various available hose diameters. That is, 11/2, 13/4, and 2-inch hoses require a 11/2 inch extractor and a 11/2 inch inductor; a 21/2 inch hose requires a 21/2 inch extractor and a 21/2 inch inductor. Attached to inductor 24 is check valve 25, to which is connected air brake line 26. Brake line 26 connects to the pumper truck&#39;s air brake air storage tank (not shown). The flow of air from truck 2 through air brake line 26 is regulated by a gauge and set of valves shown generally at reference numeral 28. 
     The air delivery system of the present invention is intended to be used only in an emergency such as when a fireman is delayed inside a burning building and wants to conserve the supply of air in tank 10; the system is not intended to replace the self-contained breathing apparatus conventionally worn by firemen. Typically, the air delivery system will be needed if part of a burning building collapses, temporarily trapping one or more firemen inside until rescue occurs. Because the air delivery system delivers air through the water hose, it is important that a fireman using the system not be immediately at risk from flames; when the air delivery system is in use, water to douse such flames will be temporarily unavailable. 
     The air delivery system is put into operation as soon as fireman 6 inside a burning building uses his radio to signal a fireman outside the building that the air supply in tank 10 is running low. The outside fireman immediately attaches air inductor 24 to the junction of first hose 4 and attack line 8, and also connects air brake line 26 to check valve 25 and to the air brake air storage tank of truck 2. Air inductor 24 and check valve 25 are shown in greater detail in FIG. 6. 
     The outside fireman then opens main valve 30, resulting in delivery of air having a pressure of 120 psig at a rate of 15 cubic feet per minute. The air flows through air brake line 26, inductor 24, and attack line 8, thereby purging any water remaining in attack line 8. Check valve 25 prevents water from entering brake line 26 from line 8. Fireman 6 can direct the purged water to any hot spots or fire remaining in his vicinity. 
     As soon as the water is purged from attack line 8, fireman 6 disconnects mask hose 16 from regulator 14 and connects mask hose 16 to one of three quick-connect ports 23 of air extractor 22, shown in greater detail in FIGS. 4 and 5. At that time the fireman will begin breathing air from the truck&#39;s brake air reservoir rather than from tank 10. After air begins to flow to fireman 6, the outside fireman adjusts main valve 30 until gauge 32 indicates an air pressure of approximately 10 psig. At that pressure, three fireman can be simultaneously supported by air provided through attack line 8 to their individual mask hoses 16 connected to respective ports 23 of extractor 22. Check valve 31, located between main valve 30 and gauge 32, is a safety feature to protect the truck&#39;s brake system in the event check valve 25 fails. 
     Although air from the truck&#39;s brake air system is breathable, it often has an oily aroma. The National Fire Protection Association (NFPA) Code 1500 §5-3.4 requires that breathing air supplied to fireman meet a certain quality standard not commonly achievable with brake air. Therefore, it is preferable to connect a higher quality air supply to the delivery system as soon as possible. FIG. 2 shows relief air cylinder 34 containing breathing standard quality compressed air at a pressure of approximately 2,000 psig, which is connected by means of high pressure line 36 to pressure regulator valve 38 attached to air brake line 26 upstream of gauge 32. Regulator valve 38 reduces the air pressure from 2,000 psig to approximately 300 psig, which is the maximum pressure rating of attack line 8. The outside fireman can further reduce the air pressure to approximately 8-50 psig by manipulating cylinder valve 39 located at relief cylinder 34. As an alternative to using relief air cylinders, the outside fireman can connect air brake line 26 to a cascade truck (not shown) which contains an essentially unlimited supply of high quality air in several breathing quality standard air cylinders refillable by an air compressor located on the cascade truck. 
     As soon as the breathing standard quality air supply is connected to brake line 26, the outside fireman closes main valve 30 to prevent high pressure air from entering and damaging the pumper truck&#39;s brake system. If the outside fireman neglects to close main valve 30, check valve 31 will prevent high pressure air from entering the brake system. 
     In the alternative embodiment shown in FIG. 7 and 8, air inductor 24, and gauge and valve assembly 28, have been replaced by air shifter module 40 located inside pumper truck 2. As with the previous embodiment, air extractor 22 is placed directly behind nozzle 9. When fireman 6 radios to outside firemen that he needs an extended supply of air, the outside fireman simply turns off the water supply to main hose 4 by manipulating one of the handles 41, and pulls switch 42 corresponding to the particular attack line 8 being used by fireman 6. When switch 42 is turned on, a signal is fed through wire 44 to air shifter module 40. In response to the signal, module 40 directs the flow of air from air brake storage tank 48, supplied by air pump 50, through air line 52 into module 40. Air exits module 40 through air outlets 54 and flows into air supply lines 56 which connect to water lines 58 leading to main hose 4. As with the previous embodiment, a breathing standard quality supply of air can be provided by connecting to air line 52 relief air cylinder 34, or a cascade system. Several parallel modules 40 can be positioned on a truck, to supply air to many main hoses at once. When switch 42 is turned off, air flow to main hose 4 ceases. Air relief valves 60 automatically open to release any air remaining inside module 40. 
     It is to be understood that the present invention is not limited to the particular construction and arrangement of parts disclosed and illustrated herein, but embraces all such modified forms thereof which are within the scope of the following claims.