Surgery – Respiratory method or device – Means for removing substance from respiratory gas
Reexamination Certificate
2002-04-11
2004-03-09
Lo, Weilun (Department: 3761)
Surgery
Respiratory method or device
Means for removing substance from respiratory gas
C128S201220, C128S201290, C128S205270, C128S205290, C128S205250
Reexamination Certificate
active
06701925
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of Invention
This invention relates to respiratory protective systems, and more particularly to an advanced protective respiratory hood for protecting a wearer from contaminants including, but not limited to nuclear, chemical, biological, smoke and dust.
2. Background of the Invention
Devices that clean the air as it is drawn or forced through one or more filters are known as air purifying respirators (herein “APRs”). Standard APRs utilize a negative pressure system in which contaminated air is pulled through a filter upon inhalation, allowing the wearer to breathe clean, filtered air. A full-face mask pertains to protective masks which protect the wearer's eyes, face, and lungs from contamination. A half-face mask or half-mask does not protect the eyes, upper face and forehead. Rather, it is generally known in the art as a triangular-shaped cup that covers the mouth and nose of the wearer. Chemical resistant hoods protect the wearer against chemical agents such as “liquid mustard” which can cause severe burns to the head and neck. Hooded respirators are generally secured around the circumference of the neck and benefit from enhanced protection of the head area.
Military organizations, such as the U.S. Army, consistently place a number of objectives high on their list for respiratory protective devices. With soldiers carrying more equipment, there is an emphasis on reducing weight and bulk whenever possible. While full-face masks provide good protection to the wearer, they are difficult to compactly store and transport. Half-mask designs are more compact, but they do not protect the eyes, ears and head of the wearer from airborne contaminants.
Another need in both military and non-military operations is excellent outward visibility. Masks and hoods that fog due to accumulation of carbon dioxide and moisture from exhaled air severely inhibit a solider from successfully completing his mission. Furthermore, many designs have filters and other structures that encumber a soldier's ability to sight a weapon or which may be snagged on other equipment.
Another need exists for a mask or hood that remains engaged during sudden movement. A number of designs, particularly those with a single filter, are subject to substantial torque when a wearer moves his head suddenly because the mass of the device is not equally distributed about the axis of the rotation for the wearer. This can cause the protective seal of the device to become disengaged, and thus the protection factor is compromised.
Another need exists for a device that uses readily available filtration media. Many designs in the prior art utilize proprietary filters which are solely intended to operate with a single design of respiratory protective device. This increases the manufacturing, quality control and inventory overhead for supporting the devices.
Another need exists for a protective hood respirator with improved verbal communication. Mouth-piece respirators are generally not acceptable where verbal communication is required as the mouth-piece must be disengaged to speak. Half-mask and full-face masks do permit verbal communication as they generally employ a cup that surrounds the mouth and nose.
Accordingly, what is needed in the art is a respiratory device that stores in a compact unit, provides substantially fog-free, unencumbered outward visibility, is stable and stays engaged to the wearer, even during violent movements, utilizes off-the-shelf filtration media, and provides verbal and drinking capability.
It is, therefore, to the effective resolution of the aforementioned problems and shortcomings of the prior art that the present invention is directed.
However, in view of the prior art in at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified needs could be fulfilled.
SUMMARY OF THE INVENTION
The present invention comprises protective respiratory apparatus having a neck-sealable hood adapted to enclose the head of a wearer, the hood having an interior and an exterior. It is preferred that the hood be constructed of an elastomeric material such as butyl rubber or neoprene. Although fabric-type materials have been successfully employed in protective hoods in the past, elastomeric material is substantially quieter which may be particularly critical in military and law enforcement operations.
At least one filter is sealingly secured to the hood wherein air passing from the outside of the hood to the inside of the hood is filtered of contaminants. However, it is preferred that two filters be employed in symmetrical relation to the hood, and more specifically in the area proximate to the location of the wearer's mouth and nose would be. The dual filter design has a number of advantages which include better outward vision in comparison to large, bulky center-mounted filters, lower breathing resistance, and better distribution of mass wherein less torque is suffered from sudden head movements due to the more equal distribution of weight. Still another advantage of the dual filter design is its ability to compact in tight relation, particularly when used with a flexible hood and half-mask.
The filters are sealed to the hood about the periphery of the filters. In one embodiment of the invention, the filters are fitted substantially flush with the exterior of the hood. The advantage to this configuration is that the bodies of the filters do not interfere with the operations of the wearer or get snagged on other equipment.
A half-mask cup adapted to sealingly cover the nose and mouth of the wearer is positioned inside the hood. The half-mask cup is mechanically, but not fluidly coupled to the filters. Accordingly, filtered air is not immediately drawn into the half-mask cup, but into the interior of the hood. It should be noted that while the half-mask cup is a preferred breathing interface for the invention, additional breathing interfaces may also be employed including, but not limited to, full-face masks and mouth-piece interfaces. A coupling part interconnects the filter to the half mask cup, the coupling part being imperforate so that it is impervious to fluid flow. A filtration part of the filter is pervious to fluid flow and is disposed radially outward from the coupling part. The fluid flow follows a path of travel through the filtration part, into the interior of the hood, flowing over the visor and into the half mask cup. The filter is therefore understood to be mechanically coupled to the half mask cup and fluidly coupled to the interior of the hood.
At least one air intake valve is integrated in the cup wherein filtered air resident in the interior of the hood is drawn into the half-mask cup for respiration by the wearer. A flexible and substantially transparent visor, preferably constructed of flexible urethane, is sealingly engaged to the hood and adapted to provide outward vision for the wearer. Preferably, the at least one air intake valve in the cup is located proximate to the nose bridge of the wearer whereby filtered air resident in the interior of the hood is drawn across the visor and into the at least one air intake valve responsive to inhalation by the wearer. The advantage of this configuration is that carbon dioxide and humidity, the primary culprits in visor fogging, are substantially reduced or eliminated by the air flow path across the visor.
In another embodiment of the invention, the hood includes at least one convexity disposed in outward relation from the interior of the hood analogous to a finger on a glove. The convexity has an axis of symmetry substantially similar to an individual filter. An aperture coincident with the axis of symmetry slideably receives and secures a filter by compressive interference fit. It is worthy to note this advancement over the prior art wherein past apertures were simply formed by a die cut on a two-dimensional plane. By forming the finger-like projection, the surface area seal between the elastomeric hood and the filter is overwhelmingly increa
Erezo Darwin P.
Hopen Anton J.
Lo Weilun
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