Ventilation – Having inlet airway – With adjustable valve
Reexamination Certificate
1999-03-30
2001-04-17
Joyce, Harold (Department: 3749)
Ventilation
Having inlet airway
With adjustable valve
C251S061100, C454S256000, C454S902000
Reexamination Certificate
active
06217441
ABSTRACT:
FIELD OF THE INVENTION
The present invention is generally related to building heating, ventilating, and air conditioning. Specifically, the present invention is related to inflatable bladders for tightly sealing ducts in response to chemical or biological attack. In particular, the present invention includes portable, rapidly expandable bags suitable for quick placement in large air ducts of public buildings.
BACKGROUND OF THE INVENTION
The recent demise of the cold war and decline in super-power tensions has been accompanied by an increase in concern over the viability of weapons of mass destruction such as chemical and biological (CB) weapons. CB weapons include chemical agents such as phosgene, nerve agents such as Sarin, and biological agents such as anthrax or small pox. CB weapons may be delivered to occupants within a building by releasing the agents external to the building but close to an air intake of the building. The air intake may be located near the ground or near the roof or somewhere in between, depending on the building architecture. Agents may also be released within a public area of a building, and be dispersed to other, private areas of the same building. Agents released in one area of a building may be further dispersed by the heating, ventilating, and air conditioning (HVAC) system of the building. It is possible that building air may be removed from the room of release and dispersed by the HVAC system itself through the building. If building air is recycled by mixing return air with intake air, as is sometimes the case, either intentionally or inadvertently, then the HVAC system may effectively deliver an agent from one room to the entire building.
Agents may be delivered in vehicles giving some warnings as to the delivery, such as missiles. Agents may be delivered in vehicles giving no warning, such as a pedestrian held putative asthma inhaler activated near an air intake.
Certain buildings, such as key military sites, can be equipped or designed well in advance to deal with the use of CB weapons. Other buildings, however, such as hotels that are hosting dignitaries or a head of state may be more susceptible to a CB weapons attack. What would be desirable therefore, is a system for sealing air ducts of a building that can be placed and activated on short notice.
SUMMARY OF THE INVENTION
The present invention includes a system for sealing an air duct of a building including an inflatable bladder coupled to means for initiating inflation. A harmful agent detector such as a chemical or biological detector (CBD) can be used in a manual mode to activate an alarm and rely on a human to initiate duct sealing or can be used in conjunction with a controller system in an automatic mode to automatically initiate duct sealing. In one embodiment, the bladder includes a rapidly reacting chemical composition that rapidly creates a volume of gas sufficient to inflate the gas bag.
One class of expandable bladders includes envelopes formed of non-resilient material that does not stretch an appreciable amount under pressure. The non-resilient bags are preferably oversized relative to the duct in which they are to be placed. The oversized bladders have sufficient surface area to extend into the duct corners and seal the ducts. Another class of expandable bladders includes envelopes formed of resilient material, which stretches under pressure. The resilient or elastic envelopes can stretch into the corners of, for example, rectangular air ducts to seal the corners.
Some expandable bladders are positioned along one internal wall of a duct. Other expandable bladders are pre-positioned between two corners of a rectangular duct and can be paired with another bladder or bladder portion disposed between two different corners of an opposing internal wall. Pre-positioned bladders can be held in place using mechanical, magnetic, or any other means. Pre-positioning bladders in duct internal corners can provide corner and wall sealing at the outset, leaving the duct interior to seal upon inflation.
It is contemplated that the duct may be reinforced when an expanding gas filled envelope might compromise duct integrity. Ducts may be reinforced internally with internal sleeves or externally with frame members disposed around the duct exterior. Ducts may also be reinforced by using external frame members held in place by internally disposed cross-members extending through the duct interior.
A preferred source of expansion gas includes chemical compositions that generate large amounts of gas when a reaction is initiated, often by an electrical spark or rapidly heated wire. Gas may be supplemented or even supplanted by use of an expanding foaming agent. The foaming agent can be used in part to force an envelope into duct corners to insure corner sealing. The foaming agent can be used to make the envelope's expansion permanent, insuring that the duct will remain sealed even if the gas leaks from the envelope. The foam is preferably rapidly expanding and hardening, and can be similar to foams used for in-place foam packing applications and home and building insulation applications.
In use, a building can be protected by selecting proper ducts and disposing expandable gas bladders within the ducts. Wiring can be extended to the outside of the duct, and may terminate locally through wires to a receiver which can be connected to an antenna. Chemical or biological detectors can be installed in select locations, including locations within ducts and within public areas of the building, and also can be located external to the building. Horizon detectors can be installed external to the building. The detectors can be either hardwired or linked with RF signals to a controller. The controller can either be run in manual mode, requiring a human to initiate envelope inflation, or can be run in automatic mode, using the controller to initiate envelope inflation.
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Cunningham Thomas B.
Howard, III John D.
Pearman A. Noel J.
Honeywell International , Inc.
Joyce Harold
Shudy, Jr. John G.
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