US20130233325A1 - Face mask for deflecting respiratory aerosols generated by the wearer - Google Patents

Face mask for deflecting respiratory aerosols generated by the wearer Download PDF

Info

Publication number
US20130233325A1
US20130233325A1 US13/698,504 US201113698504A US2013233325A1 US 20130233325 A1 US20130233325 A1 US 20130233325A1 US 201113698504 A US201113698504 A US 201113698504A US 2013233325 A1 US2013233325 A1 US 2013233325A1
Authority
US
United States
Prior art keywords
face
facemask
air
mask
subject
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US13/698,504
Other languages
English (en)
Inventor
Gerald Smaldone
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Research Foundation of State University of New York
Original Assignee
Research Foundation of State University of New York
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Research Foundation of State University of New York filed Critical Research Foundation of State University of New York
Priority to US13/698,504 priority Critical patent/US20130233325A1/en
Priority claimed from PCT/US2011/035594 external-priority patent/WO2011149637A2/en
Assigned to THE RESEARCH FOUNDATION OF STATE UNIVERSITY OF NEW YORK reassignment THE RESEARCH FOUNDATION OF STATE UNIVERSITY OF NEW YORK ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SMALDONE, GERALD
Publication of US20130233325A1 publication Critical patent/US20130233325A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/12—Cooking devices
    • H05B6/1209—Cooking devices induction cooking plates or the like and devices to be used in combination with them
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/12—Cooking devices
    • A—HUMAN NECESSITIES
    • A41—WEARING APPAREL
    • A41D—OUTERWEAR; PROTECTIVE GARMENTS; ACCESSORIES
    • A41D13/00—Professional, industrial or sporting protective garments, e.g. surgeons' gowns or garments protecting against blows or punches
    • A41D13/05—Professional, industrial or sporting protective garments, e.g. surgeons' gowns or garments protecting against blows or punches protecting only a particular body part
    • A41D13/11—Protective face masks, e.g. for surgical use, or for use in foul atmospheres

Definitions

  • the present invention relates to a facemask adapted to provide a means of directing aerosol plumes expelled by a wearer of the facemask in a ventilated enclosure to flow upward toward the roof or ceiling of the enclosure or downward toward the floor of the enclosure, away from the mid-level space (“eye-level”) of the enclosure.
  • the invention relates, further, to a method of reducing the likelihood that expelled aerosol will be inhaled by occupants of the enclosure.
  • Airborne diseases transmitted in aerosol droplets when infected persons exhale, cough or sneeze, continue to challenge public health professionals and health care providers, particularly in the context of controlling outbreaks of airborne communicable diseases. Especially urgent is the need for a means of intervening effectively when a new, highly communicable, serious or life threatening disease breaks out in a population, particularly if the disease is resistant to treatment or difficult to treat with existing therapies.
  • the social and economic advantages of living in urban environments only add to the urgency, inasmuch as one often realizes those very advantages by intermingling with others at high density in environments such as subways, workplaces, hospitals, schools, malls and restaurants.
  • SARS severe acute respiratory syndrome
  • Disposable and non-disposable facemasks have been employed for many years in an effort to limit the transmission of airborne communicable diseases.
  • Masks were first used in medical practice to prevent contamination and resulting infection of patients, particularly during surgery.
  • individuals who are exposed, or suspect they will be exposed, to infectious aerosols have resorted to wearing one or another version of a facemask to protect them from the threat.
  • Much current literature focuses on inhalational barrier protection (filtration) to be worn by healthcare workers (“HCW”) [8-11].
  • the standard protective facemask is a disposable, air-permeable paper or paper-like mask that falls generally into one of two categories: molded, cup-shaped masks and fold-flat masks.
  • Molded cup-shaped masks offer the advantage of having a firmly constructed mask body that tends to contact the cheeks, chin and bridge of the nose but is spaced apart from the wearer's nose and mouth. They may be formed from one or more layers of air-permeable material. Examples of such masks are described in U.S. Pat. Nos. 4,536,440; 4,807,619; 4,850,347; 5,307,796 and 5,374,458.
  • Fold-flat masks are constructed to fold flat for storage and to open out to provide a cup-shaped air chamber or plenum over the mouth and nose of the wearer during use. These masks may also be formed from layers of material permeable to air. Examples of fold-flat masks are described in U.S. Pat. Nos. 5,322,061; 5,020,533; 4,920,960 and 4,600,002.
  • the recommendation of the fold-flat mask is based on the assumption that influenza is contracted via direct contact or by the transmission of large (>5 ⁇ m), airborne droplets [6], whereas bird flu, SARS and H1N1 are transmitted in smaller ( ⁇ 5 ⁇ m) aerosolized particles that would be better intercepted by the greater filtration capability of N95 respirators [7].
  • large (>5 ⁇ m), airborne droplets [6] whereas bird flu, SARS and H1N1 are transmitted in smaller ( ⁇ 5 ⁇ m) aerosolized particles that would be better intercepted by the greater filtration capability of N95 respirators [7].
  • HCW inhalational barrier protection
  • Facemasks qualify as “respirators” if they have a means of supplying breathing air to the wearer that is cleaner (at least presumably) than the air the wearer would breathe absent the respirator.
  • the aforementioned air-permeable material that comprises typical disposable masks is thought to provide this capability by filtering and “scrubbing” air as it flows into the mask upon inhalation, such that contaminants are left behind in or on the mask material.
  • Various means of preventing or reducing the intake of potentially contaminated air that “leaks in” around the filter element have been devised, including wires, stays, resilient materials and adhesives to urge the edges of the mask against the cheeks, chin and bridge of the nose.
  • Masks for use by a source of contamination rely on filtration-type devices that presumably capture exhaled or expelled contaminants such as pathogen-laden aerosol particles before they can reach ambient air. Again, measures may be taken to discourage leaks of exhaled air at the upper, lower and lateral edges of the mask, with the intention of forcing as much of the exhaled air as possible through the mask's filtering elements.
  • the filtering elements also provide the major pathway for taking air in, although means for reducing resistance to the influx of inhalation air have been devised.
  • facemasks are “dual-use” devices. That is, the wearer may intend to protect himself from being a recipient of airborne infectious diseases, or he may intend to protect others by relying on the mask to limit the “broadcasting” of airborne pathogens when he exhales, coughs or sneezes. In either case, he wears the same or a similar mask.
  • facemasks in public areas such as hospitals, mass transit systems and other places of congregation as well as poultry processing facilities is sometimes mandated by health authorities to limit the spread of outbreaks of potentially serious diseases capable of airborne transmission.
  • health authorities In addition to ordering the wearing of facemasks, health authorities have historically taken additional precautions by ordering the quarantine or exclusion of persons considered at high risk of spreading or contracting an infection. Faced with the influenza pandemic of 1918, for example, the state of New York issued an order prohibiting congregation of citizens in public areas.
  • SARS outbreak in China that occurred between November, 2002 and July, 2003, the Chinese government quarantined residents of certain areas to prevent the potential spread of the disease.
  • CDC Centers for Disease Control
  • Human influenza is thought to be transmitted from person to person primarily via virus-laden droplets that are generated when infected persons cough or sneeze. These sometimes relatively large droplets (>5 ⁇ in diameter) can be directly deposited onto the mucosal surfaces of the upper respiratory tract of susceptible persons who are near (viz., within 3 feet) of the droplet source. Transmission also may occur through direct and indirect contact with infectious respiratory secretions or infectious expiratory droplets or airborne droplet nuclei. Without regard to their size, the CDC refers to all such droplets as “respirable.”
  • a combination of infection control strategies is recommended by public health authorities to decrease transmission of influenza in health-care settings. These include placing influenza patients in private rooms when possible, and having health-care personnel wear masks for close patient contact (i.e., within 3 feet) and gowns and gloves if contact with expiratory droplets is likely.
  • the use of surgical (or “procedure”) masks by infectious patients is generally thought to help contain their expiratory droplets and limit exposure to others.
  • having health-care personnel wear masks for close contact with the patient may prevent nose and mouth contact with respiratory droplets.
  • disposable surgical and procedure masks have been used widely in healthcare settings to prevent exposure to respiratory infections, but they have not been used commonly in community settings (e.g. schools, businesses, and public gatherings).
  • the invention provides an air-permeable facemask adapted to deflect a flow of aerosolized particles in air exhaled or expelled from the nose or mouth of a subject who is a source of contaminated or putatively contaminated aerosol particles.
  • expelled air, with aerosol particles dispersed therein is deflected upward or downward out of the mask, and not laterally.
  • the embodiments In enclosed, ventilated spaces, the embodiments have the advantage of reducing the accumulation of exhaled aerosol particles at mid-level in the enclosed space (i.e., at “eye level”) where other occupants can readily inhale them or adsorb them on their skin or clothing.
  • the upwardly deflected exhalants form plumes that are advantageously diluted in ambient air overhead.
  • the downwardly deflected exhalants form plumes that are advantageously adsorbed on the clothing of the source, or diluted in air circulating near the floor of the enclosed space.
  • ventilation in the enclosure removes diluent air and replaces it with fresh (or “make-up”) air.
  • the invention provides a facemask configured to be worn by a subject, said subject having a face comprising a medially disposed nose extending cephalad to a nose-bridge, a mouth disposed inferiorly to said nose, and a chin disposed inferiorly to said mouth, cheeks laterally, eyes cephalad of said cheeks and a forehead cephalad of said eyes, wherein said subject exhales or expels aerosol particles from said nose or mouth, and wherein said facemask comprises an air-permeable body having, in use, an outer surface facing away from said face, an inner surface facing toward said face, an upper edge cephalad, a lower edge caudad, and lateral edges at each side of said face such that:
  • the facemask further comprises an eye-level region spaced apart from, and covering, at least a portion of said eyes. In still another embodiment, the facemask further comprises a forehead-level region spaced apart from, and covering, at least a portion of said forehead.
  • the inner surface of said facemask comprises lateral regions spaced apart from said cheeks.
  • said upper and lower edges of said facemask are spaced apart from said face medially.
  • said lateral edges of said facemask contact said cheeks.
  • said lateral edges are urged into contact with said cheeks by an urging means.
  • said facemask is configured such that said volume of air expelled from said nose or mouth comprises a first portion deflected cephalad to create a first deflected volume, and a second portion deflected caudad to create a second deflected volume. In a preferred embodiment, at least a portion of said first or second deflected volume flows out of said facemask to create a deflected aerosol plume.
  • said volume of air expelled from said nose or mouth comprises a third portion deflected laterally toward said lateral edges of said mask body to create a third deflected volume.
  • said first and second deflected volumes, in combination are greater than said third deflected volume.
  • said inner surface of said facemask is spaced apart from said face to create a plenum.
  • said plenum comprises a first portion disposed over said nose and said mouth, and a second portion disposed lateral to said nose and mouth bilaterally.
  • said first portion of said plenum is sized relative to said second portion such that said first portion is of a greater size than said second portion.
  • said first portion of said plenum extends cephalad to a first opening at said upper edge of said facemask body, wherein said face and said upper edge define said first opening.
  • said first portion of said plenum extends caudad to a second opening at said lower edge of said facemask body, wherein said face and said lower edge define said second opening.
  • said body of said facemask comprises a rigid material. In another embodiment, said body comprises a flexible material. In one embodiment, said flexible material is elastic.
  • said body of said facemask comprises a first portion comprising an air-impermeable material and a second portion comprising an air-permeable material.
  • said plenum of said facemask cannot sustain within it over an entire breathing cycle a positive pressure relative to ambient air outside said plenum.
  • the invention comprises a system comprising:
  • said enclosed space comprises an overhead space, a mid-level space disposed below said overhead space and a lower-level space disposed below said mid-level space, wherein said overhead and mid-level spaces are contiguous and in fluid communication and wherein said mid-level and lower-level spaces are contiguous and in fluid communication.
  • said enclosure is ventilated.
  • said ceiling, wall or floor is fenestrated.
  • said enclosure is ventilated at a rate of at least five enclosure volume exchanges per hour.
  • said enclosure is ventilated by an air handler.
  • the invention provides a method of positioning a facemask on a human subject, comprising a) providing a facemask comprising an air-permeable body having an outer surface, an inner surface, an upper edge, a lower edge and lateral edges; and b) positioning said facemask on the face of said human subject such that said outer surface faces away from the face of said subject, said inner surface faces toward said face, said upper edge is positioned cephalad, said lower edge is positioned caudad, and said lateral edges contact each side of said face such that:
  • the invention provides a method of reducing an accumulation of aerosol particles in at least a mid-level space of a ventilated enclosure consequent to an aerosol plume created by a subject in said enclosure, the method comprising the steps of:
  • said subject has, or is suspected of having, a disease spread by airborne aerosol particles.
  • the term “or” when used in the expression “A or B,” where A and B may refer to a composition, object, disease, product, etc., means one or the other (“exclusive OR”), or both (“inclusive OR”).
  • exclusive OR means one or the other
  • inclusive OR means one or the other
  • the term “comprising” when placed before the recitation of steps in a method means that the method encompasses one or more steps that are additional to those expressly recited, and that the additional one or more steps may be performed before, between, and/or after the recited steps.
  • a method comprising steps a, b, and c encompasses a method of steps a, b, x, and c, a method of steps a, b, c, and x, as well as a method of steps x, a, b, and c.
  • the term “comprising” when placed before the recitation of steps in a method does not (although it may) require sequential performance of the listed steps, unless the context dictates otherwise.
  • a method comprising steps a, b, and c encompasses, for example, a method of performing steps in the order of steps a, c, and b, the order of steps c, b, and a, and the order of steps c, a, and b, etc.
  • altering and grammatical equivalents as used herein in reference to any entity and/or phenomenon refers to an increase and/or decrease in the quantity of the entity in a given space and/or the intensity, force, energy or power of the phenomenon, regardless of whether determined objectively, and/or subjectively.
  • the terms “increase,” “elevate,” “raise,” and grammatical equivalents when used in reference to the quantity of an entity and/or the intensity, force, energy or power of a phenomenon in a first sample relative to a second sample mean that the quantity of the entity and/or the intensity, force, energy or power of the phenomenon in the first sample is higher than in the second sample by any amount that is statistically significant using any art-accepted statistical method of analysis.
  • the increase may be determined subjectively, for example when a patient refers to their subjective perception of disease symptoms, such as pain, clarity of vision, etc.
  • the quantity of the substance and/or phenomenon in the first sample is at least 10% greater than the quantity of the same substance and/or phenomenon in a second sample.
  • the quantity of the substance and/or phenomenon in the first sample is at least 25% greater than the quantity of the same substance and/or phenomenon in a second sample. In yet another embodiment, the quantity of the substance and/or phenomenon in the first sample is at least 50% greater than the quantity of the same substance and/or phenomenon in a second sample. In a further embodiment, the quantity of the substance and/or phenomenon in the first sample is at least 75% greater than the quantity of the same substance and/or phenomenon in a second sample. In yet another embodiment, the quantity of the substance and/or phenomenon in the first sample is at least 90% greater than the quantity of the same substance and/or phenomenon in a second sample. Alternatively, a difference may be expressed as an “n-fold” difference.
  • the terms “reduce,” “inhibit,” “diminish,” “suppress,” “decrease,” and grammatical equivalents when used in reference to the quantity of an entity and/or the intensity, force, energy or power of a phenomenon in a first sample relative to a second sample mean that the quantity of an entity and/or the intensity, force, energy or power of a phenomenon in the first sample is lower than in the second sample by any amount that is statistically significant using any art-accepted statistical method of analysis.
  • the reduction may be determined subjectively, for example when a patient refers to their subjective perception of disease symptoms, such as pain, weakness, etc.
  • the quantity of quantity of an entity and/or the intensity, force, energy or power of a phenomenon the first sample is at least 10% lower than the quantity of the same substance and/or phenomenon in a second sample. In another embodiment, the quantity of the substance and/or phenomenon in the first sample is at least 25% lower than the quantity of the same substance and/or phenomenon in a second sample. In yet another embodiment, the quantity of the substance and/or phenomenon in the first sample is at least 50% lower than the quantity of the same substance and/or phenomenon in a second sample. In a further embodiment, the quantity of the substance and/or phenomenon in the first sample is at least 75% lower than the quantity of the same substance and/or phenomenon in a second sample. In yet another embodiment, the quantity of the substance and/or phenomenon in the first sample is at least 90% lower than the quantity of the same substance and/or phenomenon in a second sample. Alternatively, a difference may be expressed as an “n-fold” difference.
  • a “standard” quantity of an entity and/or a “standard” intensity, force, energy or power of a phenomenon relates to that quantity, intensity etc. found in a control or “null” experiment conducted when all controllable variables are held constant or have known values.
  • a “standard accumulation” of airborne aerosol particles may be the number of aerosol particles captured on a filter placed three feet from a source of an aerosol plume generated by a single cycle of a source of the plume wherein said plume is directed at said filter under a pre-determined, reproducible set of conditions.
  • contact when used herein to refer to physical contact between two bodies or surfaces, encompasses passive contact and, especially, contact reinforced or maintained by an applied force or pressure or other menas of urging one of the bodies or surfaces into contact with the other.
  • the term “deflect,” and variants thereof, generally refers to a change in the direction of an inertially moving object consequent to a collision of that object with a surface from which the object rebounds.
  • the twin may be used to describe a displacement of a structural element (e.g., twisting, bending) under a load. It is not intended that the size of the moving object be limiting, although microscopic objects such as gas molecules and particles suspended in air find frequent reference herein. Neither is it intended that the moving object be isolated in any way.
  • the term may refer to a deflection of a stream or train of objects flowing in bulk. Moreover, the objects or particles in the stream need not be disposed in a uniform or ordered configuration.
  • Microscopic liquid droplets suspended in and moving through air are a relevant but non-limiting example.
  • the “interception” of an inertially moving object by a surface may result in its deflection, “adsorption,” or “absorption.” Interception alters the vector that describes the speed and direction of the moving object.
  • the intercepted object may adhere to the surface (“adsorption”), with or without wetting the surface, or it may bounce off the surface (“deflection”).
  • “Adsorbed” substances may ultimately be “absorbed.” That is, they may dissolve or disperse in other substances that comprise the material.
  • flow refers generally to the movement of a gas or liquid and, more specifically, to the rate of such movement, measured either as a volume or a mass of the fluid passing a given area in a unit of time.
  • an “aerosol” is a suspension of dry or liquid microscopic particles dispersed in a gas.
  • the term refers particularly to liquid droplets that are suspended in the breath of subjects or that migrate therefrom into ambient air in an enclosure occupied by such subjects. It is to be understood that water vapor in the breath is not an aerosol.
  • Subjects make or “generate” aerosol particles in many ways, including but not limited to condensation of water vapor into microscopic droplets.
  • particle refers herein especially to colloidal particles, defined as particles mixed with at least one other substance or material in a single phase, wherein no individual particle is visible.
  • Liquid droplets suspended in air are exemplary.
  • air encompasses air as it is found in the earth's atmosphere, conditioned air, air enriched with oxygen, carbon dioxide and other gases compatible with life, and, without limitation, pollutants, odorants, and antimicrobial agents.
  • ambient refers to properties that pervade an environment. The composition (or temperature, etc.) of “ambient air” in an environment is approximately invariant from place to place in that environment.
  • facial features face, nose, mouth, chin, cheeks, eyes, forehead
  • regions of the face may be identified herein by these features.
  • the region of the face at “eye-level” extends approximately from eyebrows to upper cheeks.
  • the bridge of the nose is a medial structure but is at eye-level.
  • the region above the eyebrows to the (non-receded) hair line encompasses the forehead.
  • Facial features are somewhat variable even within an individual. For example, opening the mouth redefines the “layout” of facial features to some extent.
  • a facial region defined herein by a facial feature is intended to take such variability into account.
  • a facemask element that “covers the mouth” refers to an element that is capable of covering an open mouth or a closed mouth, unless otherwise specifically noted.
  • a “source” refers to a subject who generates and expels aerosol in the course of breathing (tidally or otherwise), coughing, sneezing, etc.
  • a “recipient” or “receiver” refers to a subject who inhales or receives such aerosol on the surface of his body.
  • “Contamination,” and variants thereof, refers generally to an impurity or unwanted substance mixed with or contacting another material.
  • contamination refers especially to pathogenic bacteria, viruses, and the like, but it is not intended that the term be limited thereto. Any substance or material for which embodiments of the invention reduce recipient exposure is a contaminant.
  • the term “caudad,” when used in conjunction with the face of a wearer of a mask according to embodiments of the invention, is interchangeable with the term “downward” and means “toward the feet” when the wearer is standing, walking or sitting.
  • “Cephalad” is interchangeable with the term “upward” and means “in a direction opposite to caudad” when a wearer of the mask is standing, walking or sitting.
  • enclosure is used herein interchangeably with “enclosed space,” “indoors” and the like. It is not intended that an enclosure be air-tight or sealed off from a larger space. Any enclosure having a roof or ceiling, a floor and wall elements therebetween that substantially delineate the enclosed space is within the scope of the term. Non-limiting examples of an enclosure include tents, residential dwellings, a room within a dwelling, an office or conference room in a building, a passenger car in a train or subway, etc. As used herein, the term “ventilation” relates to the movement of air into an enclosure from a source outside the enclosure. It is not intended that the term be limited to any particular means of moving or transferring the air or any particular rate of movement.
  • the enclosure may be ventilated naturally by means of an open window or door (a “fenestration”), for example, or by forcing air to move by means of fans (intake fans, exhaust fans, air handling systems, etc.).
  • the ventilation system may be “closed” such that a portion of the moving air is recycled and another portion is exhausted from the enclosure to be replaced by “make-up” air obtained from outside the enclosure.
  • a combination of air-moving means may be employed, and the combination may vary over time.
  • accumulation is used herein to refer to any increase over time of a quantity, amount, volume or mass of a substance on a unit of surface or within a space.
  • the unit of surface or space on or in which the accumulation takes place is said to have been “exposed” to that quantity, amount, volume or mass of the substance.
  • WPF workplace protection factor
  • facemasks used to prevent or help prevent subjects in a workplace or other enclosure from inhaling aerosol particles expelled by a subject also occupying that enclosure.
  • WPF equals the ratio of exposure without a mask to exposure with a mask. Any means of reproducibly measuring such exposures is within the scope of the invention.
  • One means is to use a filter adapted to capture and count all of the aerosol particles in air passing therethrough. Such filters, one of which is described herein, are well-known in the art.
  • inhalation refers to the movement of an amount of air from a region outside the body of a subject into a space within the subject.
  • the term generally refers to a subject's taking of air from outside the body into the alveoli of the lung, but can encompass “sniffing,” “gulping,” etc. Air so moved may be referred to as an “inhalant.”
  • Exhalation refers to movement of an amount of air within an airway or lung of a subject to a space outside the body.
  • Air so moved may be referred to as an “exhalant.” It is not intended that the term be limited by the rate at which such air moves or the force of the exhalation. Thus, The expulsion of air associated with coughing, sneezing, eructation, speaking, singing or whistling, for example, is an exhalation herein.
  • a substance means to reduce the concentration of the substance in a phase (a “diluent”) in which the substance is dissolved, suspended or dispersed.
  • the term “wear” and its variants e.g., “wearer”
  • facemasks refers to the use of a facemask by a subject for the purposes described herein. It will be understood that “wear” or “wearing” is not intended to connote only protection of the wearer. In some embodiments, the wearer uses the facemask to protect others.
  • An “urging means” as used herein relates to any means of initiating or maintaining a contact between two elements.
  • a non-limiting but pertinent example is an elastic band or ribbon secured to the lateral edges of a facemask in such a manner that stretching the band around the back or the crown of the head creates a tension that causes the lateral edges of the facemask to firmly contact the lateral aspects of the cheeks.
  • an adhesive or other sealant might be used to maintain such contact.
  • region refers to an area or a space distinguishable by landmarks or boundaries from other regions of that area or space.
  • Relevant landmarks and boundaries may be anatomical, geometric, or otherwise as long as they provide a frame of reference that is reproducible for purposes of describing embodiments of the invention.
  • the face extends “laterally” from the corners of the mouth to the ears and comprises the cheeks.
  • the “medial” region of the face comprises the nose, mouth and chin.
  • the “positioning” of facemasks referred to herein is described in the context of these anatomical features.
  • An enclosure may have an “overhead region,” or “overhead space,” defined as a space extending downward from the roof or ceiling of the enclosure to a level just above the heads of occupants of the enclosure, a “lower-level region” or “lower-level space” extending upward from the floor of the enclosure to a level at the waists of the occupants, and a “mid-level region” or “mid-level space” therebetween.
  • plenum refers to a chamber or enclosure that may contain a quantity of a gas or other fluid at a positive pressure relative to pressure outside the chanber.
  • rigid refers to any material that is stiff in the sense that it resists distortion (by twisting, bending, stretching, or compression).
  • the term is intended to encompass both “elastic” and “inelastic” materials.
  • An applied force may distort an elastic material, but when the applied force is removed, the material tends to return to its original shape.
  • An inelastic material tends not to return to its original shape.
  • a “flexible” material may also be either elastic or inelastic, but it is less resistant to distortion than a rigid material.
  • an “air-permeable” material may encompass materials that permit air to flow through them only under pressures substantially greater than atmospheric, the term refers more particularly herein to materials through which a subject can inhale comfortably when the material is covering the subject's nose and mouth. It will be understood that a material need not be in contact with the nose or mouth to “cover” the nose or mouth, but may be spaced apart therefrom. An “air-impermeable” material interferes with the flow of air through the material. As used herein, the term is not intended to convey “absolute” impermeability. Where an embodiment requires impermeability, its extent is sufficient if it achieves the objective of the embodiment.
  • air-permeable material similarly, is sufficiently permeable if it achieves an objective served by permeability.
  • air-permeable and “aerosol permeable” (or impermeable) are used interchangeably herein unless the context dictates otherwise
  • a “breathing cycle,” as used herein, means the period of time required for a subject, beginning at the moment he has completed expelling a first volume of air from an airway, to take in a next succeeding volume of air into an airway and expel that volume out of the airway and ending at the moment he begins to take in a next succeeding volume.
  • FIG. 1 Model of Source/Receiver/Environment interaction. Parameters that can be set or measured are shown.
  • FIG. 2 Schematic representation of experimental set-up. Breathing pattern of both Source and Receiver; tidal volume 500, rate 15, and duty cycle 0.5. Environmental flow in chamber was regulated via opening between hood and chamber. Cascade impactor measured particle distribution of aerosol inhaled by Receiver. Exposure defined by radioactivity captured on Exposure filter in Receiver.
  • FIG. 3 Experimental setup for Source aerosol measurements.
  • FIG. 4 Particle Distributions and Mass Median Aerodynamic Diameters for all stages of the cascade impactor. Mean+/ ⁇ CI for each stage are plotted as log particle size ( ⁇ m) vs. probability.
  • FIG. 5 Side-view of head showing plenum in fluid communication with upper and lower openings of mask body.
  • FIG. 6 Front view of head showing upwardly and downwardly deflected aerosol plumes.
  • FIG. 7 Photograph in side view showing aerosol plume expelled without facemask.
  • the present invention relates to a facemask for reducing the likelihood that occupants in an enclosed space will inhale or be exposed to aerosol particles expelled by individuals when they exhale, cough or sneeze in that enclosure.
  • the facemask is not intended to rely simply on trapping aerosol particles as the individual emits them from nose and mouth.
  • the mask is not intended to rely on filtering, “scrubbing” or otherwise sterilizing the expelled air or substantially reducing the number of aerosol particles that reach ambient air overall.
  • the invention provides a facemask adapted to direct the aerosol plumes expelled by a wearer of the mask to flow upward toward the roof or ceiling of the enclosure and downward toward the floor of the enclosure, and not into the mid-level space (“eye-level”) of the enclosure.
  • exhaled or expelled plumes are advantageously diluted in ambient air overhead, and then removed in air being vented from the space.
  • exhaled plumes are advantageously directed downward to be adsorbed on the clothing of the source, or diluted in air circulating near the floor of the enclosed space.
  • the invention provides a method of reducing the likelihood that expelled aerosol will be inhaled by occupants of the enclosure.
  • the mask may be a rigid material formed in a mold, for example, the upper edge thereof preferably does not contact the bridge or sides of the nose, or regions of the cheeks in the proximity of the nose.
  • Prior art devices are variously adapted to ensure such contact.
  • U.S. Pat. Nos. 4,037,593, 5,357,947 and 5,699,792 are exemplary.
  • elements extending from the inner surface of the mask to contact the surface of the face are contemplated.
  • they act as spacers to stabilize the opening formed by the upper edge of the body of the mask, but it is not intended that such spacers materially interfere with the bulk flow of gases through the opening. It is to be understood that such spacers are contemplated solely as an example, not by way of limitation.
  • the body of the mask may comprise a rigid material, molded or shaped to define and preserve a space between the inner surface of the mask body and the face except at the lateral edges of the mask body.
  • the molding preserves a shape that conforms to the contour of the cheeks and lower jaw such that the mask, in use, contacts facial surfaces.
  • Flexible elastic elements in and near the lateral edges may be included to ensure that such contact is maintained when the contour changes or when pressure in the space between the inner surface of the mask's body and the face changes. It may be advantageous to employ stays or adhesives to keep the lateral edges in contact with the face.
  • the mask may be held in place over the face with ties or elastic bands that extend behind the head, or ear-loops or other means known in the art. It is contemplated that these means for holding the mask in place will cooperate with the aforementioned stays, elastic elements and adhesives to further encourage contact between the lateral edges of the mask body and the face.
  • the lower edge of the body of the mask spaced apart from facial surfaces in the proximity of the chin.
  • elements extending from the inner surface of the mask to contact the surface of the face are contemplated as spacers. And again, it is not intended that such spacers materially interfere with the bulk flow of gases through the opening formed by the surface of the face and the lower edge of the body of the mask. It will be understood that alternatives to spacers are also contemplated, including molding the mask with a rigid material that preserves the spacing.
  • the lower edge of the mask preferably extends below the lower extent of the wearer's open mouth and may be configured to permit unobstructed articulation of the lower jaw.
  • masks in accordance with the invention need not be constructed of rigid materials, either in whole or in part.
  • Acceptable materials include flexible materials such as paper and other non-woven materials, fabric, and resilient materials, provided only that they a) can be suitably spaced apart from the surface of the face medially when the mask is in use, b) resist deterioration from moisture, c) are sufficiently permeable to air to permit wearers of the mask to breathe comfortably, and d) are generally suitable to be worn by humans externally on the face.
  • An exemplary but non-limiting method of forming a mask according to the invention comprises providing at least one layer of fibrous material that can be molded to the desired shape with the use of heat and that retains its shape when cooled. Shape retention is typically achieved by causing the fibers to bond to each other at points of contact between them, for example, by fusion or welding. Any suitable material known for making a shape-retaining layer of a direct-molded respiratory mask may be used to form the mask shell, including, for example, a mixture of synthetic staple fiber, preferably crimped, and bicomponent staple fiber.
  • Bicomponent fiber is a fiber that includes two or more distinct regions of fibrous material, typically distinct regions of polymeric materials. Typical bicomponent fibers include a binder component and a structural component.
  • the binder component allows the fibers of the shape-retaining shell to be bonded together at fiber intersection points when heated and cooled. During heating, the binder component flows into contact with adjacent fibers.
  • the shape-retaining layer can be prepared from fiber mixtures that include staple fiber and bicomponent fiber in weight-percent ratios that may range, for example, from 0/100 to 75/25.
  • the material includes at least 50 weight-percent bicomponent fiber to create a greater number of intersection bonding points, which, in turn, increase the resilience and shape retention of the shell.
  • Suitable bicomponent fibers that may be used in the shaping layer include, for example, side-by-side configurations, concentric sheath-core configurations, and elliptical sheath-core configurations.
  • One suitable bicomponent fiber is the polyester bicomponent fiber available, under the trade designation “KOSA T254” (12 denier, length 38 mm), from Kosa of Charlotte, N.C., U.S.A., which may be used in combination with a polyester staple fiber, for example, available from Kosa under the trade designation “T259” (3 denier, length 38 mm) and possibly also a polyethylene terephthalate (PET) fiber, for example, available from Kosa under the trade designation “T295” (15 denier, length 32 mm).
  • PET polyethylene terephthalate
  • the bicomponent fiber may comprise a generally concentric sheath-core configuration having a core of crystalline PET surrounded by a sheath of a polymer formed from isophthalate and terephthalate ester monomers.
  • the latter polymer is heat softenable at a temperature lower than the core material.
  • Polyester has advantages in that it can contribute to mask resiliency and can absorb less moisture than other fibers.
  • the shaping layer can be prepared without bicomponent fibers.
  • fibers of a heat-flowable polyester can be included together with staple, preferably crimped, fibers in a shaping layer so that, upon heating of the web material, the binder fibers can melt and flow to a fiber intersection point where it forms a mass, that upon cooling of the binder material, creates a bond at the intersection point.
  • a mesh or net of polymeric strands could also be used in lieu of thermally bondable fibers. An example of this type of a structure is described in U.S. Pat. No. 4,850,347 to Skov.
  • the web When a fibrous web is used as the material for the shape-retaining shell, the web can be conveniently prepared on a “Rando Webber” air-laying machine (available from Rando Machine Corporation, Cincinnati, N.Y.) or a carding machine.
  • the web can be formed from bicomponent fibers or other fibers in conventional staple lengths suitable for such equipment.
  • the layer preferably has a basis weight of at least about 100 g/m 2 , although lower basis weights are possible. Higher basis weights, for example, approximately 150 or more than 200 g/m 2 , may provide greater resistance to deformation and greater resiliency.
  • the shaping layer typically has a maximum density of about 0.2 g/cm 2 over the central area of the mask.
  • the shaping layer would have a thickness of about 0.3 to 2.0, more typically about 0.4 to 0.8 millimeters.
  • Examples of shaping layers suitable for use in the present invention are described in the following patents: U.S. Pat. No. 5,307,796 to Kronzer et al., U.S. Pat. No. 4,807,619 to Dyrud et al., and U.S. Pat. No. 4,536,440 to Berg.
  • the above-described method of manufacture is not intended to be limiting.
  • the mask may be rigid and air-impermeable.
  • injection molding, thermoforming, transfer- and compression molding are suitable. Even masks stamped in metal may be employed.
  • FIG. 1 illustrates the principles of the model, emphasizing each measurable parameter including: the breathing patterns of the presumed infected Source and uninfected Receiver, the aerosols produced at the Source, the effects of the chamber on aerosol dilution and particle modification, the effects of filtration using filters on Source and Receiver, particle deflection by mask, and chamber air exchange.
  • Multiple potential means of protection that masks and/or respirators may offer can be evaluated, including dilution, deflection and filtration when a mask is worn either at the source (patient) or the receiver (HCW or others).
  • an enclosure 10 that defines a chamber 20 into which radiolabeled wet aerosols simulating exhaled, particles from a subject (or “Source”) are introduced. Aerosols may be defined by cascade impaction using one or more cascade impactors 30 (Marple 8-stage impactor, Thermo Fischer Scientific, Waltham, Mass., 2 liter per minute flow), a technique well-known in the art. Source aerosols may be exhaled via a ventilated mannequin head 40 (Simulaids, Saugerties N.Y.) suitable for mask protection. A similar head 50 within the chamber may be used to assess recipient exposure (the “Receiver”). The heads may be suspended from stands 60 . The head of the Source may be directed toward the Receiver or at any other angle through almost 360°. A filter 70 (Pari, Starnberg Germany) within the Receiver can be used to quantify exposure. This filter captures all inhaled particles.
  • the bench model 5 may be used to assess the effect of any mask 7 (or no mask) on different aspects of protection from potential exposure, including dilution, deflection and filtration, when worn either at the Source or the Receiver. Similarly, to evaluate the performance of any mask in various environments, the chamber's size and configuration and its ventilation parameters may be modified at will.
  • Chamber 20 may measure, for example, 135 ft 3 (5 ft. in length, 5 ft. wide, 6 ft in height).
  • the chamber is advantageously placed in the proximity of a hood suitable for exhausting radioactivity.
  • the chamber is equipped with an air intake port and is connected to the hood via an exhaust port such that a fixed (but adjustable) exchange occurs (6 exhanges per hour, for example).
  • Aerosols may be created by nebulizer 80 such as an AeroTech II nebulizer connected to a source of compressed air 90 with a flow, for example, of 10 L per minute.
  • the nebulizer 80 is filled with 3 ml of 0.9% normal saline labeled with technetium-99m and run to dryness over about 10 minutes, it will produce radiolabeled wet aerosols simulating contaminated particles exhaled during tidal breathing (Source).
  • Each head may be connected to a pump 100 (Harvard, Millis, Mass.), set to pump a tidal volume of 500 ml, respiratory rate of 15 per minute, and duty cycle of 0.5 min.
  • the pumps are preferably not synchronized.
  • the heads 40 and 50 may be placed within the chamber approximately 3 feet apart.
  • the aerodynamic distributions of expelled particles at the Source and near the Receiver may be measured by cascade impaction, as noted above (Marple 8-stage impactor, Thermo Fischer Scientific, Waltham, Mass., 2 liter per minute flow).
  • Source aerosols may be measured by an in-line impactor 110 as shown in FIG. 3 .
  • the impactor 30 as illustrated in FIG. 2 , measures particles exhaled from the Source that reach the vicinity of the Receiver. Exposure is quantified by filter 70 .
  • smoke tracer experiments may be performed within the chamber to assure that there are no ambient air currents. If ambient air currents are desired, they may be introduced and evaluated by smoke tracer experiments. Such experiments are conducted by providing a plume of visible aerosol particles, such as smoke rising from the tip of a lit cigarette, and plotting its motion vectors.
  • the experimental design outlined above is organized to assess factors likely important in exposure, dilution, deflection and filtration of defined aerosols.
  • the chamber and mannequin head set-up are constructed (CDC recommended distance of 3 feet apart[5]) to mimic two individuals sitting in a room representing a typical environment.
  • the choice of a tidal breathing pattern best represents the most common clinical interaction between two persons.
  • the choice of aerosols reflects the characteristics of wet aerosols that are exhaled by humans during tidal breathing [14, 15].
  • Max Ex Maximum exposure
  • Radioactivity captured by either the exposure filter (at Receiver) or mask (at Source or Receiver) may be measured with a calibrated well counter ( ⁇ 10 Kemble Instruments, Hamden, Conn.) or a calibrated Ratemeter (>10 Ludlum Measurements Inc., Sweetwater Tx). Data may be presented as percent of nebulized particles and expressed as mean+/ ⁇ confidence intervals. Separation of confidence intervals define statistical significance.
  • the ratio of Max Ex to actual exposure defines a Workplace Protection Factor (WPF, NIOSH) [16].
  • the goal of mask protection is to reduce exposure to the Receiver independent of environmental engineering control systems. At least for aerosols generated under conditions comparable to those experienced in the HCW environment, manipulating the Source rather than trying to simply protect the Receiver is highly advantageous, becoming optimal when a mask is sealed to the sides of the Source's face and has vents cephalad and caudad ( FIGS. 4 , 5 ). When sealed to the Receiver, by contrast, particles passed through the mask and are inhaled.
  • FIG. 1 illustrates the principles of the model emphasizing each measurable parameter including: the breathing patterns of the presumed infected Source and uninfected Receiver, the aerosols produced at the Source, the effects of the chamber on aerosol dilution and particle modification, the effects of filtration using filters on Source and Receiver, particle deflection by mask, and chamber air exchange.
  • FIG. 2 is a schematic representation of the experimental setup.
  • a chamber measuring 135 ft 3 5 ftl ⁇ 4.5 ftw ⁇ 6 fth was constructed.
  • the chamber was placed next to a hood with a small connection providing a fixed, defined flow providing 6 air exchanges/hr.
  • Aerosols were created by an AeroTech II nebulizer (3 devices used in rotation, Biodex, Shirley, N.Y.) connected to an air tank with a flow of 10 L per minute.
  • the nebulizer was filled with 3 ml of 0.9% normal saline labeled with technetium-99m and run to dryness over about 10 minutes.
  • Source aerosols simulating contaminated particles exhaled during tidal breathing (Source).
  • Source aerosols were exhaled via a ventilated mannequin head (“Brad” Model #2512, Simulaids, Saugerties N.Y.) suitable for mask protection and directed towards the Receiver.
  • a similar ventilated head was placed within the chamber to assess recipient exposure (Receiver).
  • Each head was connected to a Harvard pump (Harvard Apparatus SN#A52587, Millis, Mass.), tidal volume 500 ml, respiratory rate of 15, and duty cycle of 0.5.
  • the ventilators were not synchronized.
  • the heads were placed within the chamber approximately 3 feet apart.
  • the experimental design was organized to assess factors likely important in exposure, dilution, deflection and filtration of defined aerosols.
  • the chamber and mannequin head set-up were constructed (CDC recommended distance of 3 feet apart [5]) to mimic two individuals sitting in a room representing a typical environment.
  • a tidal breathing pattern was chosen in order to best represent the most common clinical interaction between two persons. Aerosols were chosen based upon the characteristics of wet aerosols that are exhaled by humans during tidal breathing [14, 15].
  • FIG. 5 and FIG. 6 illustrate a mask design according to an embodiment of the invention.
  • the Model #GCFCXS, Crosstex N95 mask, which is equipped with metal stays to ensure tight closure over the nose-bridge and chin was modified by bending the stays to ensure that the edges of the mask would remain spaced apart from the nose-bridge and the chin.
  • the modified mask was further modified to ensure that the lateral edges remained spaced apart from the cheeks.
  • MMAD Mass Median Aerodynamic Diameters
  • Masks placed on the Source further decreased particle size near the Receiver with approximately 85% sub-micronic and an average MMAD of 0.483 ⁇ m (95% CI 0.408-0.558), 0.461 ⁇ m (95% CI 0.450-0.47), and 0.470 ⁇ m (95% CI 0.290-0.650) when the LSM, TSM and N-95 masks were placed on the Source respectively.
  • Exposure to the Receiver and the corresponding sWPF are shown in Table 1 (left panel). Data are separated by process and reported as percentage of nebulized particles. The quantified effects of each maneuver on exposure are best illustrated in the sWPF. Max Ex averaged 1.09% (95% CI 0.902-1.29) indicating the effect of dilution (i.e. from 100%). Applying either a surgical mask or N95 respirator at the source resulted in significant reductions in exposure and corresponding sWPFs of 260-350.
  • Radioactivity captured by each mask quantified the effectiveness of filtration on exposure.
  • SN95 resulted in significantly greater filtration averaging 35.7% (95% CI 27.7-43.7) in comparison to STSM 13.4% (95% CI 10.8-16.1) and SLSM 5.98% (95% CI 5.22-6.74).
  • significantly greater filtration did not result in a significant reduction in exposure indicating deflection was the dominant factor.
  • the sealed N95 respirator (SN95Vas) was representative of filtration combined with deflection at the Source which provided the best protection overall in terms of sWPF (4104). Filtration captured a mean of 81.0% (95% CI 59.5-102) of the particles. When placed on the Receiver (RN95Vas) the protective value diminished to a sWPF of 119 capturing an average of 0.453% (95% CI ⁇ 0.020-0.926).
  • Table 3 compares a conventionally fitted mask to two “open” modifications of the same mask. Opening the mask's plenum cephalad and caudad improves WPF by almost an order of magnitude over that provided by a mask that relies solely on filtration. The entire gain is lost when the mask is additionally opened laterally.
  • Aerosols generated were comparable to those experienced in the HCW environment. It was observed that wet aerosols emitted from a potentially infectious Source evaporate to sub-micron particles capable of penetrating the N95 respirator. The model disclosed herein consistently demonstrated that containing exhaled particles at the Source resulted in greater protection to the Receiver. Mask filtration with a respirator appeared effective only when physically sealed to the Source's face.
  • sWPF ranged from 16 to 101.
  • the superior level of protection at the Source seen with environmental flow using a sealed respirator (SN95Vas) with a sWPF of 4000 was due to a combination of filtration and deflection, dropping to a sWPF of 16 when deflection was eliminated (environmental flow of 0).
  • N95 respirators Numerous studies have focused only on filtration efficiency of both N95 respirators and surgical masks placed on the Receiver [8-11, 17].
  • NIOSH requires that N95 respirators filter 95% of a test aerosol of 0.3 ⁇ m particles [10, 18].
  • aerosols measured near the receiver, (0.5 ⁇ m or smaller) overlap in distribution with potentially infectious viral particles [10, 19].
  • Mask filtration does not play a significant role in reducing exposure to the recipient unless a respirator is physically sealed to the face of the Source. Deflection of exhaled particles, such as can be achieved with a surgical mask worn at the Source, achieves far greater levels of protection than an N95 respirator on the recipient, provided that there is some degree of airflow in the enclosure that Source and Receiver occupy. Thus, for example, a nurse in a one on one situation with a patient may optimally reduce his/her exposure by placing a surgical mask on the patient after insuring that there is some degree of airflow in the room. This situation also maximizes HCW compliance because the HCW does not need to wear a mask.
  • the HCW may expect only a minimal degree of protection from any mask.
  • the HCW worker is further protected if the Source is wearing a mask that properly contacting the cheeks laterally and has a plenum that is open communication above and below with the environment.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Physical Education & Sports Medicine (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Cookers (AREA)
  • Respiratory Apparatuses And Protective Means (AREA)
US13/698,504 2010-05-14 2011-05-06 Face mask for deflecting respiratory aerosols generated by the wearer Abandoned US20130233325A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US13/698,504 US20130233325A1 (en) 2010-05-14 2011-05-06 Face mask for deflecting respiratory aerosols generated by the wearer

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
SE1000509-8 2010-05-14
SE1000509A SE1000509A1 (sv) 2010-05-14 2010-05-14 Bärbar Induktionsanordning
US34765310P 2010-05-24 2010-05-24
PCT/US2011/035594 WO2011149637A2 (en) 2010-05-24 2011-05-06 Face mask for deflecting respiratory aerosols generated by the wearer
US13/698,504 US20130233325A1 (en) 2010-05-14 2011-05-06 Face mask for deflecting respiratory aerosols generated by the wearer

Publications (1)

Publication Number Publication Date
US20130233325A1 true US20130233325A1 (en) 2013-09-12

Family

ID=43243885

Family Applications (2)

Application Number Title Priority Date Filing Date
US13/698,504 Abandoned US20130233325A1 (en) 2010-05-14 2011-05-06 Face mask for deflecting respiratory aerosols generated by the wearer
US13/696,914 Abandoned US20130256300A1 (en) 2010-05-14 2011-05-13 Portable device for induction cooking

Family Applications After (1)

Application Number Title Priority Date Filing Date
US13/696,914 Abandoned US20130256300A1 (en) 2010-05-14 2011-05-13 Portable device for induction cooking

Country Status (6)

Country Link
US (2) US20130233325A1 (de)
EP (1) EP2570002A1 (de)
CN (1) CN103004286A (de)
AU (1) AU2011251905B2 (de)
SE (1) SE1000509A1 (de)
WO (1) WO2011141571A1 (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150306432A1 (en) * 2010-08-31 2015-10-29 Crosstex International, Inc. A filter mask having one or more malleable stiffening members
US11122843B2 (en) 2019-01-17 2021-09-21 Benjamin Emery Systems and methods for relief from face mask ear loops
CN114073829A (zh) * 2020-08-13 2022-02-22 深圳华大智造科技股份有限公司 带有采样功能的口罩及其配套样本采集管
WO2022040247A1 (en) * 2020-08-17 2022-02-24 Massachusetts Institute Of Technology Respiratory system simulator systems and methods
USD1001998S1 (en) 2019-06-21 2023-10-17 Benjamin Emery Mask

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE1000509A1 (sv) * 2010-05-14 2010-09-02 Electrolux Ab Bärbar Induktionsanordning
WO2017087983A1 (en) * 2015-11-19 2017-05-26 Pahmet Llc Integrated and compartmentalized system for food storage and processing
WO2020120030A1 (en) * 2018-12-11 2020-06-18 Arcelik Anonim Sirketi An induction heating cooker

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1199529A (en) * 1915-11-04 1916-09-26 Ford Heard C Face-protector.
US4965887A (en) * 1987-11-12 1990-10-30 John A. Paoluccio Face protector for splash and spatter protection
US5419318A (en) * 1991-05-21 1995-05-30 Better Breathing, Inc. Breathing mask

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4399351A (en) * 1980-12-05 1983-08-16 William Koff Electric heat exchange cooking apparatus
US6279471B1 (en) 1995-09-15 2001-08-28 Jeffrey Reddoch Drilling fluid recovery defluidization system
JPH11102778A (ja) * 1997-09-29 1999-04-13 Matsushita Electric Ind Co Ltd 誘導加熱調理器
US20030030342A1 (en) * 1998-02-10 2003-02-13 Chen James C. Contactless energy transfer apparatus
US20040016348A1 (en) * 2002-07-24 2004-01-29 Richard Sharpe Electronic cooking pan systems and methods
US6157011A (en) * 2000-05-19 2000-12-05 Lai; Hui-Wen Electromagnetic stove structure
JP2005149990A (ja) * 2003-11-18 2005-06-09 Toshiba Home Technology Corp 加熱調理器
CN1812673A (zh) * 2006-02-20 2006-08-02 张敬胜 电磁发热器及带有电磁发热器的电磁炉
US7690124B1 (en) * 2008-01-31 2010-04-06 Bruce Sangeet Henry Self-supporting stud finder with line-laser
EP2365252B1 (de) * 2010-03-13 2015-07-01 Electrolux Home Products Corporation N.V. Herd
SE1000509A1 (sv) * 2010-05-14 2010-09-02 Electrolux Ab Bärbar Induktionsanordning

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1199529A (en) * 1915-11-04 1916-09-26 Ford Heard C Face-protector.
US4965887A (en) * 1987-11-12 1990-10-30 John A. Paoluccio Face protector for splash and spatter protection
US5419318A (en) * 1991-05-21 1995-05-30 Better Breathing, Inc. Breathing mask

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150306432A1 (en) * 2010-08-31 2015-10-29 Crosstex International, Inc. A filter mask having one or more malleable stiffening members
US10668308B2 (en) * 2010-08-31 2020-06-02 Crosstex International, Inc. Filter mask having one or more malleable stiffening members
US11122843B2 (en) 2019-01-17 2021-09-21 Benjamin Emery Systems and methods for relief from face mask ear loops
USD1001998S1 (en) 2019-06-21 2023-10-17 Benjamin Emery Mask
CN114073829A (zh) * 2020-08-13 2022-02-22 深圳华大智造科技股份有限公司 带有采样功能的口罩及其配套样本采集管
WO2022040247A1 (en) * 2020-08-17 2022-02-24 Massachusetts Institute Of Technology Respiratory system simulator systems and methods

Also Published As

Publication number Publication date
CN103004286A (zh) 2013-03-27
WO2011141571A1 (en) 2011-11-17
SE1000509A1 (sv) 2010-09-02
AU2011251905B2 (en) 2014-11-13
US20130256300A1 (en) 2013-10-03
AU2011251905A1 (en) 2012-12-06
EP2570002A1 (de) 2013-03-20

Similar Documents

Publication Publication Date Title
US20130233325A1 (en) Face mask for deflecting respiratory aerosols generated by the wearer
Scheuch Breathing is enough: for the spread of influenza virus and SARS-CoV-2 by breathing only
Jayaweera et al. Transmission of COVID-19 virus by droplets and aerosols: A critical review on the unresolved dichotomy
Staymates Flow visualization of an N95 respirator with and without an exhalation valve using schlieren imaging and light scattering
Oberg et al. Surgical mask filter and fit performance
Weber et al. Aerosol penetration and leakae characteristics of masks used in the health care industry
CZ2003795A3 (cs) Respirátor obsahující integrovaný filtrační prvek, výdechovou chlopeň a nárazový prvek
US20080110469A1 (en) Strapless flexible tribo-charged respiratory facial mask and method
Howard et al. Sterile field contamination from powered air-purifying respirators (PAPRs) versus contamination from surgical masks
CN104162237A (zh) 横向过滤口罩
Mansour et al. Respiratory source control versus receiver protection: impact of facemask fit
US20210289854A1 (en) Individual nano-bodies protection of skin and respiratory system
Armand et al. Impact of medical face mask wear on bacterial filtration efficiency and breathability
De Silva et al. Masks in COVID-19: let’s unmask the evidence
Li et al. Wearing time and respiratory volume affect the filtration efficiency of masks against aerosols at different sizes
Sozkes et al. COVID-19 and respiratory protection for healthcare providers
Schumacher et al. Respiratory protection during simulated emergency pediatric life support: a randomized, controlled, crossover study
CN103933684A (zh) 多通道呼吸器
Paxton et al. N95 respiratory masks for COVID-19: a review of the literature to inform local responses to global shortages
GB2594299A (en) A face mask and system to remove pathogens from expired breaths, coughs, or sneezes from humans
Landry et al. Fit-tested N95 masks combined with portable HEPA filtration can protect against high aerosolized viral loads over prolonged periods at close range
Duncan et al. N95 respirators, disposable procedure masks and reusable cloth face coverings: Total inward leakage and filtration efficiency of materials against aerosol
WO2011149637A2 (en) Face mask for deflecting respiratory aerosols generated by the wearer
US20240042252A1 (en) Personal protective equipment face coverings with inherently ionic material
Roberge et al. Wearing an N95 respirator concurrently with a powered air-purifying respirator: effect on protection factor

Legal Events

Date Code Title Description
AS Assignment

Owner name: THE RESEARCH FOUNDATION OF STATE UNIVERSITY OF NEW

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SMALDONE, GERALD;REEL/FRAME:029411/0516

Effective date: 20121204

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION