Patent Grant
7467666
This description relates generally to firefighting and hazardous material abatement and more specifically to applying carbon dioxide (“CO2”) to a target material, such as a fire, hazardous material, a hydrocarbon material, or some other material that can be effectively treated with dry ice (“solid CO2”) to extinguish, or contain the target material.
Carbon dioxide is a colorless gas, which was first recognized in 1577 by Van Helmont who detected it in the by-products of both fermentation and charcoal burning. CO2 is used in solid (dry ice), liquid and gaseous form in a variety of industrial applications such as beverage carbonation, welding and chemicals manufacture. It occurs in the products of combustion of all carbonaceous fuels and can be recovered from them in a variety of ways. CO2 is widely used today as a by-product of synthetic ammonia production, fermentation, lime kiln operations, and from flue gases by absorption processes. CO2 is also a product of animal metabolism and is critically important in the life cycles of both animals and plants. CO2 is present in our earth's atmosphere in small quantities (0.03%, by volume).
Carbon dioxide (CO2) will extinguish fires in almost all combustibles except for a few active metals, metallic salts and substances containing oxygen, i.e., nitrates, chlorates.
The advantages of carbon dioxide gas for fire extinguishing purposes have been long known. As early as 1914, the Bell Telephone Company of Pennsylvania installed a number of seven pound capacity portable CO2 extinguishers for use on electrical wiring and equipment. By the 1920s, automatic systems utilizing carbon dioxide were available. In 1928, work on the NFPA Standard for carbon dioxide extinguishing systems was begun.
Over the years, two methods of applying carbon dioxide have been developed. The first technique is the total flooding application. The total flooding technique consists of filling an enclosure with carbon dioxide vapor to a prescribed concentration. This technique is applicable both for surface-type fires and potential deep-seated fires. For surface-type fires, such as would be expected with liquid fuels, a minimum concentration of 34% carbon dioxide by volume is mandated. Considerable test work has been done with carbon dioxide on liquid fuels and appropriate minimum design concentrations have been arrived at for a large number of common liquid fire hazards. This method of application has limitations in the amount and distance of applied CO2 that can be effectively delivered. This leads to a small, effective coverage area for such application.
For deep-seated type hazards the minimum permitted concentration is 50% carbon dioxide by volume. Fifty percent design concentration is used for hazards involving electrical gear, wiring insulation, motors, and the like. For hazards involving record storage, such as bulk paper, a 65% concentration of carbon dioxide is required. For substances such as fur and bag-house type dust collectors, a 75% concentration of CO2 is mandated. It should be noted that most surface burning and open flaming will stop when the concentration of CO2 in the air reaches about 20% or less. Thus, it should be apparent that a considerable factor of safety is built in to these minimum CO2 concentrations required by the Standard. Flame extinguishment has typically not been considered to be sufficient fire protection by those who developed the CO2 Standard. This is in contrast to the guidelines given in standards for other gaseous extinguishing agents. Some of these standards may mandate agent concentrations which may be sufficient to extinguish open flame but will not produce a truly inert atmosphere.
The other method of application which has been developed for carbon dioxide is referred to as local application. Local application systems are appropriate only for the extinguishment of surface fires in flammable liquids, gases and very shallow solids where the hazard is not enclosed or where the enclosure of the hazard is not sufficient to permit total flooding. Hazards such as dip tanks, quench tanks, spray booths, printing presses, rolling mills, and the like can be successfully protected by a local application type system. In this system, the discharge of CO2 is directed at the localized fire hazard. The entire fire hazard area is then blanketed in CO2 without actually filling the enclosure to a predetermined concentration.
Extinguishers have been considered a first line of defense in fighting fires. Their practical and functional use tends to render them ideal as a means of prevention and protection against all types of fires. However, the common fire extinguisher typically has only a 3-6 foot range and may have both clean-up problems and high costs. Large commercial CO2 foam solutions to fight fires tend to be expensive in more ways than one. Due to cost, effective coverage area, and safety distance requirements, the local application of CO2 may have limitations in proper fire containment and extinguishing.
It is very similar to the fire triangle which does not represent the chemical chain reaction. The fire tetrahedron is based on the components of extinguishing a fire. Each component represents a property of flaming fire; fuel 11, oxygen 12, heat 13, and chemical chain reaction 14. Extinguishment is based upon removing or hindering any one of these properties. The most common property to be removed is heat. Heat is commonly eliminated by using water. Water is used because it absorbs heat extremely well and is cost efficient. During fire operations you may see objects being placed outside a structure. Though this is commonly referred to as salvage operations, it also acts to remove any fuel from the fire. Without the objects exposed to heat there can be no flammable gasses given off to burn. The third property, oxygen, is usually the hardest to remove. Oxygen removal is typically accomplished when a carbon dioxide extinguisher is used on a fire. In more extreme cases explosives may be used on a fire. The explosion will use up the oxygen in the immediate area. Finally, the last property is the chemical chain reaction. This can be considered the reaction of the reducing agent (fuel) with the oxidizing agent (oxygen). An example of an extinguishment method by hindering the chemical chain reaction is Halon or FM200 extinguishers.
With a surface-type fire, that is, a fire which has not heated the fuel to its auto-ignition temperature much beyond the very surface of that fuel, extinguishment is rapid. Such surface fires are usually the case when liquid fuels are involved. Unfortunately, there is no guarantee that all hazards will produce surface fires. In fact, a great many hazards are more likely to produce fires which will penetrate for some depth into the fuel. Such fires are commonly referred to as deep-seated. When dealing with a so-called deep-seated potential, it is necessary not only to remove the oxygen and decrease the gaseous phase of the fuel in the area, but it may be equally important to permit the heat which is built up in the fuel itself to dissipate. If the heat is not dissipated and the inert atmosphere is removed, the fire may very easily re-flash. For such hazards, it is often necessary to reduce the concentration of oxygen and gaseous fuel to a point where not only is the open flaming stopped, but also any smoldering is eliminated. To accomplish this, the concentration of agent should be held for a sufficiently long time to permit adequate dissipation of built-up heat. The NFPA Standard 12 on carbon dioxide systems has long been a leader in prescribing thorough and conservative fire protection.
The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the invention or delineate the scope of the invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.
The present examples provide for the application and delivery of CO2 to target materials. The present examples provide a way of delivering pelletized dry ice to a target material. The examples tend to improve the manner in which the carbon dioxide is delivered to the target material and also the effectiveness of the carbon dioxide in extinguishing burning target material and/or containing target material that would otherwise contaminate its environment. Specifically the present examples provide pelletized carbon dioxide, and can deliver the pelletized carbon dioxide onto the target material from a distance, thus tending to improve the effectiveness of the pelletized carbon dioxide while tending to minimize the exposure and maximize the safety of those who deliver the pelletized carbon dioxide to the target material. In addition nitrogen (N2) may be used in alternative examples to aid in the delivery of pelletized CO2 as using it in pumping the pellets may tend to eliminate moisture and aid pumping.
Moreover, according to an example, the manner in which delivery of pelletized carbon dioxide to the target material can be provided by a mobile unit, that can be selectively positioned relative to the target material. Thus, a source of pelletized carbon dioxide can be selectively positioned relative to the target material, and the pelletized carbon dioxide can be delivered from a distance onto the target material.
According to the present example, carbon dioxide is applied to a target material, by providing pelletized carbon dioxide, and delivering the pelletized carbon dioxide, e.g., by projecting the pelletized carbon dioxide (e.g., by a turret or its equivalent), spraying, spraying the pelletized carbon dioxide (e.g., through a hose), hand delivery (e.g., by buckets or shovels), by aerial dropping the pelletized carbon dioxide by use of gravity, or other commonly known delivery methods.
The types of target material with which the present invention is designed to apply the pelletized carbon dioxide may include, e.g., hydrocarbon material, hazardous material, burning material, and other materials that if not contained would otherwise contaminate its environment.
Also, the carbon dioxide may be pelletized to a size range of about 3 mm to 100 mm pellets diameters. This size may improve the manner in which the carbon dioxide is delivered to the target material, and also may maximize the effectiveness of the pelletized carbon dioxide in dealing with the target material.
Many of the attendant features will be more readily appreciated as the same becomes better understood by reference to the following detailed description considered in connection with the accompanying drawings.
The present description will be better understood from the following detailed description read in light of the accompanying drawings, wherein:
Like reference numerals are used to designate like parts in the accompanying drawings.
The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utilized. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.
In fire containment and extinguishing, it has been known to apply liquid or gaseous carbon dioxide to the burning material. While the use of liquid or gaseous carbon dioxide to extinguish fires or contain hazardous materials is generally effective, there may be ways in which the delivery and effectiveness of the carbon dioxide can be improved. Specifically, applicant has developed a systems and methods in which carbon dioxide may be delivered to a target material by pelletizing the carbon dioxide (to “pelletized dry ice”, or “pelletized CO2”) and providing equipment that can deliver the pelletized dry ice onto the target material from a distance, and in sufficient quantity, thus tending to improve the effectiveness of the carbon dioxide, while minimizing the exposure and maximizing safety of those who deliver the carbon dioxide to the target material. Moreover, delivery of the pelletized carbon dioxide to the target material can be accomplished by a delivery system that tends to be mobile, and can be selectively positioned relative to the target material.
As discussed above, the present examples allows delivering solid carbon dioxide (CO2) (i.e., dry ice) to a target material. The apparatus may be designed to improve the manner in which the carbon dioxide is delivered to the target material, and the effectiveness of the carbon dioxide in dealing with the target material. Specifically the present example provides pelletized dry ice and can deliver the pelletized dry ice onto the target material from a significant distance, thus minimizing the exposure and maximizing the safety of those who deliver the dry ice to the target material.
The principles of the application of pelletized carbon dioxide are described below in connection with two examples of mobile systems for applying pelletized carbon dioxide to a target material. However, the application of pelletized carbon dioxide can be achieved with other equivalent. In addition, the following detailed description relates to target material in the form of burning material, or to hazardous materials that need to be contained, but from that description the manner in which the principles of the present invention can be used with other types of target materials will also be apparent to those in the art.
Definitions: In this application,
The equipment is shown schematically in
The pellet pump may be equipped with a nitrogen inlet. The nitrogen supplied to the pump may be in either liquid or gaseous form. Nitrogen may be used in gaseous form to aid in pumping the pellets. Using nitrogen may eliminate air and the moisture typically contained in air, which may tend to cause jams in the pumping system through condensation and freezing. Alternatively pure nitrogen or a mixture of air and nitrogen may be used to produce satisfactory pumping of the pellets.
The source of liquid carbon dioxide is connected to the equipment, e.g., via the liquid carbon dioxide inputs 108a on the pelletizer 108. The source of liquid carbon dioxide may be, e.g., a tank or a trailer delivery device that may be included in the skid/platform or may be external to the skid/platform. The equipment may be powered by generator 106, e.g., a 120 hp-550 hp Diesel Generator, with a 240 volt 3 phase 60 Hz power rating, or an equivalent power source. The computer 114 starts the motors for the pelletizer 108 and the pellet pump 110. The pelletizer 108 is configured to produce solid carbon dioxide (dry ice) pellets in a predetermined size range (for example in 3 mm to 100 mm diameter range). The carbon dioxide pellets are then ejected from the pelletizer into the hopper 112, or into some other storage and containment device. The carbon dioxide pellets are drawn into the pump 110 by an impeller or equivalent method, e.g., under a head pressure of about 100 psi-250 psi., (the exemplary pump 110 may uses a 125 hp-250 hp electric drive motor and has the capability to produce a 600-2000 gpm water flow as a pellet alternative). The carbon dioxide pellets are delivered from the pump 110, e.g., in a pressure range of 100 psi-180 psi.
As further illustrated by
In all other respects, the equipment of
While the foregoing description relates to delivering the pelletized carbon dioxide by projection or by spraying, other ways of delivering pelletized carbon dioxide to a fire, hazardous material, hydrocarbon, or other material that if not contained could contaminate its environment are contemplated. For example, it is contemplated that in alternative examples the pelletized carbon dioxide could be delivered to a target material, from a distance, by aerial drop 302, so that the pelletized carbon dioxide is dropped from an aircraft and falls by gravity onto the target material. The carbon dioxide would be pelletized, and then stored on the aircraft and dropped from the aircraft, using the type of techniques that are conventionally used in fighting forest fires.
A further alternative example provides an in building system configured to deliver pellets to a fire or hazardous material spill. By delivering carbon dioxide to a nozzle at a high pressure at room temperature a temperature drop produced may cause the carbon dioxide to solidify producing the effect previously described to extinguish a fire or contain a hazardous material spill.
In any event, irrespective of the manner of delivery, it is noted that the carbon dioxide be in the 3 mm to 100 mm size range. That size range may be designed to optimize the (i) amount and density of the pelletized carbon dioxide that is delivered to the target material, (ii) coverage area, and (iii) effectiveness of the carbon dioxide delivered to the target material. That size range may be particularly effective when the pelletized carbon dioxide is projected or sprayed onto the target material, since the effectiveness of the pelletized carbon dioxide is largely a function of pellet size, distance (projected or sprayed) and the coverage provided by the pelletized carbon dioxide. Moreover, it is believed useful to restate the manner in which the pelletized carbon dioxide deals with a target material such as a fire. The pelletized carbon dioxide (i) “freezes” the fuel, dropping ignition point temperature, (ii) displaces the oxygen, with the carbon dioxide, extinguishing the open burning, (iii) dissipates heat due to the −109° F. temperature of the carbon dioxide, and (iv) by “freezing” the fuel and displacing the oxygen, the eliminates the chemical reaction that fuels the fire.
In using the examples described above the resulting environmental cleanup time and costs may be reduced compared to current conventional and acceptable techniques. An additional benefit may be the resulting reduction in environmental damage because of the speed at which the target materials become controlled and/or contained compared to current and acceptable ways and techniques known by the art. Another benefit may be the reduced risk of exposure to the target material(s) and the increase in safety because of the further distance from the target material(s) that those delivering the pelletized carbon dioxide can be compared to current conventional and acceptable techniques.
In the case of a fire for a target material, it may be known that according to the Fire Tetrahedron, all fires have four core components: fuel, oxygen, heat and a resulting chemical reaction. The examples described may attack the components of the fire tetrahedron as follows:
4. CHEMICAL REACTION The carbon dioxide pellets “freeze” the fuel and displace the oxygen eliminating the chemical reaction. The CO2 is heavier than oxygen.
In the case of a HazMat (hazardous material as defined pursuant to title 49 of the United States code) the two issues are typically containment and cleanup. A result of applying the examples described may be:
Thus, as seen by the foregoing detailed description, providing carbon dioxide in pellet form and projecting or spraying carbon dioxide pellets or aerial dropping by gravity onto the target material from an unpredetermined distance may be accomplished. The target material may include but is not limited to, e.g., hydrocarbon material, hazardous material, a burning material, and other material that if not contained could otherwise contaminate its environment. The pelletized carbon dioxide that is projected, sprayed or dropped onto the target material may be in a size range of about 3 mm to 100 mm. Additionally, the equipment may be supported (e.g., by support structure that can comprise one or more support members) in a manner that enables the equipment to be maneuvered relative to the target material and enables pelletized carbon dioxide to be projected, or sprayed, or dropped using gravity from an unpredetermined distance onto the target material.
This application claims the benefit of U.S. Provisional Patent Application No. 60/723,049 filed Oct. 3, 2005, the contents of which are hereby incorporated by reference.
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