The invention relates to the survival and rescue of personnel in mines and other underground facilities as well as in enclosed areas having air quality or toxicity challenges from accidents, such as fires or explosions, or deliberate acts, such as terrorist attacks.
The tragic loss of hundreds of lives in underground mine fires in West Virginia, Mexico, and China in late 2005 and 2006 revealed a serious deficiency in terms of emergency response. This is exemplified by the failure to rescue underground miners who survived the initial explosion. This failure resulted primarily because of an underestimation in the time required for rescue.
As recent mine fires dramatically demonstrate, the time needed to complete recovery operations into distant and/or remote mine positions typically is not measured in several hours but rather in several days. Extended time was and will be necessary to get rescue teams on the scene, diagnose the crisis, develop a safe plan of attack, and undertake the rescue.
To mine survivors, awaiting rescue is a life-threatening ordeal. Their most vital immediate need is finding breathable air, if possible. The multiple threats survivors must endure from toxic environments such as post-fire mine environments for up to several days are typically the following:
Exposure to elevated concentrations of carbon monoxide (CO);
Exposure to elevated concentrations of carbon dioxide, (CO2);
Exposure to reduced oxygen concentrations of (O2); and
Exposure to cold, ambient mine temperatures.
Fire poisons local mine air with CO and CO2 and consumes the O2 that is required to sustain life. Depending upon the elevated or reduced levels of these gases, the toxic mine air can cause death by asphyxiation either instantly (within minutes) or slowly (over days). The outcome of the last threat could be death by hypothermia.
Miners are trained to seek a habitable atmosphere in which to barricade and take refuge while awaiting rescue. Because finding breathable air that sustains life may be impossible, there is a technological need for the survivors to create a safe volume having habitable atmospheres with breathable air on demand.
A broad embodiment of the invention discloses a kit for providing a safe volume having air breathable by humans including one or more inflatable barriers for providing the safe volume wherein one or more sides of the safe volume are provided by the inflatable barrier; a carbon dioxide absorbent for absorbing carbon dioxide from air within the safe volume; an oxygen generator for providing oxygen within the safe volume; and a catalyst for converting carbon monoxide to carbon dioxide within the safe volume. It may be useful to provide a spray foam container (e.g. spray can) for sealing the periphery of the inflatable barrier and a wall touching the inflatable barrier. Typically another embodiment provides for one or more tabs at the periphery of the inflatable barrier and a stud gun and anchors for anchoring one or more tabs to a wall touching the periphery of the inflatable barrier. Should a person arrive after the barrier has been erected a sealable entry way through the inflatable barrier for admission or exit of a human can be provided.
The kit is typically stowed in the general area where it is to be used in a sealed container that is non-permeable to air or may be permeable thereto.
Another general embodiment according to the invention includes an inflatable barrier including a flexible substantially circular or polygonal donut shaped tube having an open core; a flexible sheet disposed within the core and operationally fixed to the tube for sealing the core; a reactive gas generating apparatus disposed within or adjacent to one portion of the tube, for inflating the tube; and a reactive chemicals and catalysts disposed on one side of or within a semi-permeable membrane to process toxic atmosphere into breathable air. The reactive chemicals and catalyst typically reduce levels of CO2, and CO; and increase oxygen levels, to at least survivable levels for one to several days and in some embodiments up to one week.
A flexible foam layer disposed on a periphery of the inflatable tube is useful for reducing ingress of toxic air.
A particularly useful embodiment of the invention includes the integration of the carbon dioxide absorbent, oxygen generator, and carbon monoxide catalyst wherein waste heat from CO2 absorption and O2 generation can be used to enhance the operation of the catalyst.
Broadly, the invention provides for survival of personnel awaiting rescue in confined or closed spaces in which the atmosphere outside is not habitable for any significant length of time because of the release of toxic gases and the removal of life-sustaining oxygen as a result of fires or explosions, including underground mines (coal, salt, mineral), submarines, tunnels, and basements.
A first embodiment of the invention includes a kit for providing a safe volume in which there is available breathable air for up to 10 to 15 survivors for up to 4 to 7 days. Breathable air defined as air that allows long term survival if breathed for the duration of the stay in the safe volume.
The first element of this kit is an inflatable barrier with which to rapidly isolate a confined space within which to create a habitable atmosphere with breathable air and await rescue. Deploying a one barrier, two barriers, or only a few barriers to create a safe volume has not been the approach based on information reported in a worldwide review of the state-of-the-art by the Mine Safety and Health Administration, MSHA (Mine Escape Planning and Emergency Shelters, Washington, DC, April, 2006). Of the over 20 “emergency-shelter” technologies assessed, many of which patented, all reported that the deployment of a gas tight 3-dimensional (D) chamber was necessary to create a safe haven within which survivors would await rescue.
This unanimous thinking to deploy a chamber (providing not only the walls but also the roof and floor), instead of creating a safe haven by erecting only a few barriers, appears to be based on the lethality of one toxic gas present, CO.
The prior logic appears to be that a safe haven must be hermetically sealed to deny the infiltration of any CO. The facts are that safe havens do not have to be all encompassing and leak-free to be effective, because low levels (25 parts per million, ppm) can be tolerated for days without adverse health effects.
Relying on a 2-D rather than 3-D deployment configuration greatly improves the pre-positioning, deployment, and re-deployment of the equipment needed to create a safe volume on-demand. Deploying only a few barriers to build a safe volume constitutes one embodiment of this invention.
Referring now to
Referring now to
Referring now to
Referring now to
Referring now to
A further embodiment of the invention is a kit having a chemical for removing carbon dioxide. The carbon dioxide removal may be according to “Delivery System for Carbon Dioxide Absorption Material”, U.S. Pat. No. 6,699,309, Mar. 2, 2004, assigned to Battelle. This technology, known as the “Lithium Hydroxide (LiOH) Curtain” has been deployed by the US Navy for use on-board its submarine fleet. It is designed to be a simple, safe, and reliable to use low-cost technology by which to remove the CO2 exhaled in disable subs, improving a crew's chance to survive while awaiting rescue.
The technology typically consists of polypropylene barriers and LiOH crystals, each storable compactly in maintenance-free metal canisters with long shelf lives. When needed, the ribbed porous barriers are unrolled, loaded with LiOH crystals, and suspended in passageways as curtains. Chemical interaction between the curtain and contaminated air absorbs CO2 and generates heat (up to ˜140° F.). By lacing curtains together with tie-wraps/grommets/Velcro along the edges of the fabric, different sizes and configurations of passageways can be barricaded.
As configured, the “sub curtain” addresses only half of the processes needed for extended-miner survival: CO2 removal and heat generation. To counteract the threats of O2-depletion and elevated-CO, two other technologies need to be integrated with the CO2 absorbing curtain, one for O2-generation and the other for CO-removal.
A third embodiment according to the invention may include a kit that comprises a chemical for generating oxygen from chemicals, and not from tanks of compressed gas. One typical O2-generation technique in the embodiment is based on “O2-candle” technology, which uses exothermic reactions between solid chemicals to generate gaseous O2 at atmospheric pressure. Current commercial-of-the-shelf (COTS) O2-candles are off/full-on devices, with no control. In some embodiments of the invention the invention does not include one average micro-(one-millionth) meter particle size of solid chemicals. In other embodiments a “bimodal blend” of micro-meter and nano (one-billionth)-meter sized oxidants (chlorates, perchlorates, and superoxides) and metals (aluminum, and iron, copper or molybdenum oxide) in specific proportions are mixed to release gaseous O2 in a more controlled and extended manner.
A further embodiment according to the invention includes a kit having a catalyst for removing carbon monoxide by converting it to carbon dioxide, which is then removed by absorption. The CO-removal technique is typically any of the low-temperature (100° F.) COTS catalysts available to convert CO to CO2: silver hollandite; platinum/tin oxide; and gold/titanium dioxide.
Incorporating the embodiments for CO2 absorption, O2 generation, and CO reduction into a barrier 100, rather than having them as “stand alone” devices, constitutes another embodiment of this invention. According to details in the aforementioned MSHA review of “emergency shelters” and in MSHA Program Information Bulletin (PIB P07-03, 2007), the obvious practice is to perform each of these processes within the safe volume and not within the barriers that define it. This is obvious practice because the barriers that constitute the walls, floor, and roof of chambers are thin and intended to act only to seal rather than to function as a toxic-atmosphere conditioning device.
Simultaneously conducting CO2 absorption, O2 generation, and CO reduction in an integrated manner, rather than performing them one-at-a-time in separate devices, constitutes another embodiment of this invention. Placing the catalyst for CO conversion to carbon dioxide next to or near the oxygen generation chemical provides heat for the CO conversion process and enhances the reaction rate. According to details in the aforementioned MSHA review of “emergency shelters”, the operating characteristics of these processes do not appear to be compatible or synergistic. In particular, it is not obvious why it would be advantageous to use of waste heat from O2 generation or CO2 absorption to enhance a “low-temperature” catalyst for converting CO to CO2. The advantage comes from the fact that the efficiency of even low-temperature catalysts can be improved with rather marginal increases in temperature. The higher the efficiency, the less catalyst needed, thereby lowering weight and cost, or improving speed and efficiency of conversion.
A further embodiment includes another way in which the waste heat generated from CO2-capture and O2-generation, to induce recirculation of the atmosphere within the volume barricaded. According to details in the aforementioned MSHA review of “emergency shelters”, battery powered electric fans are required to circulate the atmosphere within chambers to avoid stratification and localized regions within which the level of CO or CO2 is concentrated and more dangerous. In this invention, heat management and flow motivation are achieved by strategically positioning the exothermic toxic-gas cleaning processes at specific horizontal and vertical locations within the barrier, and relying on molecular-weight differences and thermal gradients to induce recirculating flow. This feature allows the non-mechanical, non-electric barrier to achieve the attributes of an electric-fan system, but without the fan or battery.
Another embodiment of the invention involves the reduction of both the levels of CO2 and CO. Not widely known is that the lethality of elevated levels of CO2 and CO individually is not the same as that when these toxic gases are present simultaneously. In particular, the lethality of 5% CO2 AND 2,500 ppm CO is greater than that of 5% CO2 OR 2,500 ppm CO alone. Because of this, MSHA, of expert skills in the prior art, recommended in Program Information Bulletin (PIB P07-03, 2007) that only CO, and not both CO and CO2 levels had to be reduced in safe volumes. The present invention provides that levels of CO2 and CO are both be reduced to take advantage of this life-saving physiological effect.
Other attributes, if incorporated, are expected to enhance the functionality of the barrier:
1) An inflatable-deployment and soft-sealing system, or a means by which to inflate the periphery of the barrier, typically using solid-propellant gas generator (auto air-bag) technology, to temporarily “seal” the barrier against the roof, walls, and/or floor.
2) A hard-sealing system, or a means by which to permanently attach the edges of the barrier to the roof, walls, and perhaps floor using explosive bolts.
3) A passive-sensor system, or a calorimetric means by which to detect the extent to which CO and CO2 have been removed and O2 generated, or when a chemical has been depleted.
To our knowledge, concepts that were not thought needed or possible include the following:
1) The use of 2D barriers rather than 3D chambers to erect safe volumes;
2) The integrated, synergistic use of processes for making air containing toxic gas breathable by humans; and
3) The passive, synergistic use of waste heat to circulate flow within an enclosure.
Currently, the only option available for extending mine-fire survival is the increased use of self-contained self-rescuers (SCSRs), portable (backpack) breathing devices for individual miners. SCSRS, however, have potential drawbacks:
In short, there is an urgent critical need for a next-generation miner survival system that would be the following:
These typical attributes describe the invention, proven to be unique based on data from workshops worldwide on emergency mine safe havens. As conceived, the invention typically allows a:
While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all of the possible equivalent forms or ramifications of the invention. It is to be understood that the terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit of the scope of the invention.
This application claims the benefit of U.S. Provisional Application No. 60/810,454, Mine Curtain Survival System, Frank J. Bis et al., inventors. The entire disclosure of the above referenced provisional application is hereby incorporated by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/US2007/012643 | 5/29/2007 | WO | 00 | 11/25/2008 |
Number | Date | Country | |
---|---|---|---|
60810454 | Jun 2006 | US |