Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
  • A62B17/00—Protective clothing affording protection against heat or harmful chemical agents or for use at high altitudes
  • A62B17/04—Hoods

Definitions

• Thi ⁇ invention relates to breathing apparatus for respiratory protetion of civilians and combatants.
• the neck seal of the hood which forms an integral part of the breathing apparatus, may be sealed by a draw string ( 082/02492, EP0275934A2) but much inward leakage of the noxious external atmosphere takes place past this type of seal.
• An elasticated ⁇ eptal neck seal (GB2129670A) allows less leakage but the leakage may be further reduced by having a positive pressure inside the hood.
• a po ⁇ itive pressure may be achieved by passing exhaled gas to the hood space (GB2211098A, GB2164570A) but such designs are defective because the moisture in the exhaled gas impairs vision.
• Positive pressure breathing apparatus is well known (GB 1587121, GB 2074456A) .
• a positive pressure is achieved by pas ⁇ ing dry gas under pressure and at constant flow directly into the hood space reservoir.
• inward leakage past the ONM is not important and outward leakage fron ONM to hood space is minimised by improved goodness of fit.
• the present invention discloses breathing apparatus having a re ⁇ ervoir, in the hood space between inner and outer hoods, filled with dry breathable gas to prevent misting and under po ⁇ itive pres ⁇ ure to prevent inward leakage; having the inner hood elasticated to support the conveyance means, to pull it onto the face and to secure a good fit, and having an open circuit
• breathing apparatus to provide respiratory protection and having an outer hood, an inner hood, a reservoir at positive pressure, a breathable gas ⁇ ource and a conveyance mean ⁇ with one way valves in an open circuit system such that:
• the conveyance means covers the mouth and nose of the u ⁇ er and has:
• the outer protective hood is impervious to gas and resistant to flame to protect the head and respiratory tract of the wearer.
• the neck seal i ⁇ made of elasticated material which fits round the neck and, together with the outer hood, completes the gas impermeable enclosure.
• the conveyance means covers the nose and mouth.
• the cavity of the conveyance means is the space within it.
• the inner hood is elasticated and tightly fitting to the head. It is attached to the rim of the conveyance means, exerts even traction and pulls it onto the face to achieve a good seal.
• the reservoir i ⁇ the ⁇ pace between the outer and inner hood. It has a volume which is greater than the breathing volume of the wearer and it contains breathable gas.
• the inlet valve allows gas to pass in only one direction from the reservoir to the cavity of the conveyance means.
• the outlet valve allows gas to pass in only one direction from the conveyance means cavity to the ambient atmosphere.
• the breathable gas source is a cylinder which contains the breathable gas under pre ⁇ ure.
• the manual switch is u ⁇ ed to ⁇ witch on and off the ⁇ upply of breathable gas from the source.
• the inner and outer hoods are joined together at the circumference on the inner side of the outer hood.
• the opening of the inner hood is positioned at the front to permit vision and to make orientation obvious on donning.
• the external ambient atmosphere is outside the hood and may contain smoke particles and noxious ga ⁇ e ⁇ .
• figure 1 shows the breathing apparatus as worn by a subject and having the component parts numbered as above.
• the breathing apparatus is donned by stretching the opening 3 of the neck seal 2 and pulling the outer hood 1 over the head. This is attached 13 to the inner hood 7 which is therefore also pulled onto the head.
• the closely fitting inner hood 7 is also attached to the rim 6 of the conveyance means or mask 4 which is correctly positioned by the act of donning the hood 7 with the opening 14 at the front.
• the breathable gas source 11 is activated manually by the switch 12 and fills the reservoir 8 with breathable gas under pressure. On inspiration, breathable gas is sucked in through the inlet valve 9 and the cavity 5 of the mask 4 to the lungs. On expiration, exhaled gas passes through the cavity 5 of the mask 4 and the outlet valve 10 to the external ambient atmosphere 15. Positive pressure in the reservoir 8 is maintained by an appropriate setting for the opening pres ⁇ ure of one or other or both of the valves 9 and 10.
• the outer hood may be fire proof; the entire outer hood or only a part of it may be transparent; a draw string may be fitted round the neck; the conveyance means may be a mouth piece, oro nasal mask, full face mask or other device; the inner hood may be elasticated in more than one dimension; the inner hood attachment to the conveyance mean ⁇ rim may be direct or indirect and may be complete or incomplete; the conveyance means rim may be shaped to the face and nose; the breathable gas may be air, oxygen or mixed qas, compressed or chemically generated; a reducing valve may be required between the compressed gas cylinder and the re ⁇ ervoir; a relief valve may be required to prevent over pressurization of the re ⁇ ervoir; release of gas may be activated manually, automatically or on demand; there may be two eye openings with a central part or cord to prevent deformation of the opening or opening ⁇ ; there may be a plurality of inlet and outlet valves; the inner hood may ⁇ upport and carry the

Landscapes

• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• General Health & Medical Sciences (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Respiratory Apparatuses And Protective Means (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=10701254

Family Applications (1)

Country Status (6)

Families Citing this family (8)

Family Cites Families (4)

• 1991
  • 1991-09-12 GB GB919119441A patent/GB9119441D0/en active Pending
• 1992
  • 1992-09-10 EP EP92918936A patent/EP0632736B1/de not_active Expired - Lifetime
  • 1992-09-10 CA CA 2134069 patent/CA2134069A1/en not_active Abandoned
  • 1992-09-10 DE DE69226784T patent/DE69226784T2/de not_active Expired - Fee Related
  • 1992-09-10 WO PCT/GB1992/001656 patent/WO1994019055A1/en active IP Right Grant
  • 1992-09-10 AU AU25049/92A patent/AU679900B2/en not_active Ceased

Non-Patent Citations (1)

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