Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
  • A62B18/00—Breathing masks or helmets, e.g. affording protection against chemical agents or for use at high altitudes or incorporating a pump or compressor for reducing the inhalation effort
  • A62B18/04—Gas helmets

Definitions

• This invention relates to safety helmets and, more specifically, to safety helmets including breathing apparatus.
• Breathing apparatus in the form of the so-called "gas-mask"
• gas-mask is well known in the art and conventionally comprises a flexible face piece, -which is held to the face by straps over the wearer's head, and a filter arrangement which, in the modern form, is capable of filtering out the greater part of nuclear, and/or biological and/or chemical contaminates from the air passing to the face piece.
• a safety helmet which totally encases the wearer's head and which includes a see-through panel with a flexible annular seal surrounding the panel and extending therefrom to form a seal with the face of the wearer, whereby the see-through visor, the annular seal and the face of the wearer define an isolated volume within the helmet.
• the annular seal contacts the wearer's face across the forehead, down the cheeks and across the chin whereby the nostrils and mouth of the wearer open to said isolated volume.
• the isolated volume communicates with an air reservoir via duct means extending from said isolated volume to a demand valve arrangement, conveniently secured to the helmet, and duct means between the said demand valve and the said reservoir.
• the reservoir is normally carried by the wearer to afford unrestricted movement to the wearer.
• an exhalation valve is provided so that spent air exhaled by the wearer can be discharged from the said isolated volume.
• Such a safety helmet with breathing apparatus is, hereinafter referred to as "a helmet of the type defined.”
• the wearer has an air supply which is perfectly safe and cannot be contaminated by the surrounding atmosphere.
• Such helmets have found favour with fire fighters, rescue personnel and certain personnel in industry who may be exposed to non-breathable atmospheres.
• a conventional gas mask to conserve the air supply in the reservoir, whilst in the standby location and to remove the conventional gas mask and don the safety helmet before entering the non-breathable atmosphere where the conventional gas mask is inadequate to supply the wearer with breathable air.
• the present invention seeks to provide a safety helmet which allows the wearer to preserve the pressure air supply whilst on standby and to be readily available to enter an adverse atmosphere without delay.
• a safety helmet intended to totally enclose the head of the wearer and to define an isolated volume to which the nostrils and mouth of the wearer are open when the helmet is fitted, characterised by a first means for supplying air to said isolated volume, said first means comprising an air supply from a pressure air source to said isolated volume, a second means for supplying breathable air to said isolated volume and control valve means arranged to close the isolated volume from said second means for supplying breathable air when the said first means is supplying air to said isolated volume.
• the safety helmet includes a see-through aperture in its forward region and said aperture is closed by a see-through panel.
• the safety helmet includes a flexible annular seal, one annular end of said seal is clamped to the helmet to surround the see-through panel the other annular end of said annular seal is arranged to make pressure contact with the face of the wearer across the forehead, down the cheeks and across the chin, and whereby the volume bound by said see-through panel, said annular seal and the face of the wearer defines said isolated volume.
• the safety helmet is characterised in that the said first means, when supplying air to said isolated volume, is arranged to maintain the said isolated volume at an air pressure greater than atmosphere pressure.
• said first means include an air supply demand valve and ducting between said air supply demand valve and said isolated volume.
• a ducting extends from said air supply demand valve to a pressure air reservoir carried by the wearer of the helmet.
• the said first means includes a manually actuable valve means for selectively connecting and disconnecting the said pressure air supply to said isolated volume.
• control valve means comprise a pressure sensitive valve arrangement, adapted to close the said second means for supplying air to the isolated volume when the air pressure in said isolated volume is above atmospheric pressure.
• the said demand valve is arranged to open the pressure air supply to said isolated volume when the pressure in said volume falls below 15 mm/water above atmosphere
• the said demand valve is arranged to open to supply pressure air supply to said isolated volume when the pressure in said isolated volume falls below 10 mm/water above atmosphere.
• said second means includes a filter arrangement, arranged to filter contaminates from atmospheric air, and duct means for passing filtered air to said isolated volume.
• control valve means is located in the duct means between said filter arrangement and said isolated volume.
• the said air filter arrangement is selectively detachable from the helmet assembly.
• the helmet includes a nose cone, within the isolated volume and arranged to contact the wearer across the bridge of the nose, down the cheeks and between the mouth and the chin, and wherein said nose cone includes valves means for allowing air flow from the isolated volume surrounding the nose cone into the nose cone.
• the helmet includes an air exhalation valve for discharging spent air from the nose cone to the surrounding atmosphere.
• said air exhalation valve passes through the see-through panel and the said nose cone is supported by said exhalation valve.
• Fig. 1 shows, diagrammatically, a longitudinal cross-section through a safety helmet in accordance with the invention
• Fig. 2 shows, diagrammatically, a front view of the filter air supply arrangement for the embodiment illustrated in Fig. 1.
• a one piece safety helmet 11 intended to totally encase the head of the wearer, includes an aperture 12 in its forward regions closed by a see-through panel 13.
• a flexible annular seal 14 has a radial flange 14a at one annular end which abuts an annular region of the see-through panel 13.
• a rigid annular member 15 abuts the flange 14a and is retained with the regions of the helmet shell 11 surrounding the aperture 12, as by screws or rivets (not shown), to form air-tight seals between the helmet — o — shell 11 and a ring-like resilient member 16 surrounding the aperture 12, the member 16 and the peripheral regions of the see-through panel 13, the see-through panel 13 and the flange 14a, and the flange 14a. and rigid member 15.
• the annular seal 14 is adapted to engage the face of the wearer across the forehead, down the cheeks, and across the chin to define a volume VI within the helmet, formed by the see-through panel 13, the annular seal 14 and the face of the wearer. With this arrangement the nose and mouth of the wearer open into the volume VI and the wearer can breath only the atmosphere within the volume VI.
• the helmet also includes a harness comprising a top pad 17, supported by resilient strap means 18 secured by anchor plates 19 to the sides of the helmet shell 11, and which top pad 17 is hingedly connected at 20 to a back pad 21, .supported by resilient strap means 22 secured by anchor plates 23 to the sides of the helmet shell 11.
• the back pad 21 is substantially rigid and extends to, or just beyond, the neck part 11a of the helmet shell 11 so that, to don the helmet, the wearer simply pulls the lower regions of the back pad 21 towards the rearmost part of the helmet shell 11 to allow the head to be inserted into the helmet between the pad 21 and the annular seal 14.
• the back pad 21 can be released to engage the back of the head of the wearer and, due to the resilience of the strap means 22, the pad 21 acts on the back of the wearer's head to maintain the wearer's face in pressure contact with the edge 14b of the annular seal 14.
• a nose cone 24 is attached to an exhalation valve 25, which passes through the see through panel 13, and the periphery 24a_ of the nose cone 24, remote from the exhalation valve 25, is arranged to make pressure contact with the face of the wearer, across the bridge of the nose, down the cheeks and beneath the lower lip, thus to define a second breathable volume V2 within the first breathable volume VI.
• the volume V2 is connected to the volume VI by one-way valves 26, one at each side of the nose cone 24, and which valves 26 allow air flow from the volume VI to the volume V2 only when the pressure in volume V2 is less than the pressure in volume VI.
• the exhalation valve 25 is arranged to pass through an aperture in the see-through panel 13 and the said valve 25 is arranged to open when the pressure in the volume V2 is greater than the pressure of the surrounding atmosphere, whereby spent air can be discharged from the volume V2 through the valve 25, and the valve 25 closes when the pressure in the volume V2 is less than the pressure of the surrounding atmosphere pressure, as occurs when the wearer inhales.
• the volume VI may be supplied with breathable air via a duct 27, which opens through the annular seal 14 and extends to a demand valve 28 connectable to an air reservoir 29 via a flexible conduit 30.
• the air reservoir 29 can be slung from the belt of the wearer or carried as a back pack.
• a manually actuable valve 31 is provided for supplying air from reservoir 29 to the conduit 30 or shutting of the supply of air from the reservoir 29. to the conduit 30.
• the demand-valve 28 is set to maintain the volume VI at a pressure in excess of the pressure of the surrounding atmosphere, preferably at a pressure greater than 10 mm of water and more preferably greater than 15 mm of water above the pressure of the surrounding atmosphere.
• the safety helmet also includes an air filter arrangement 32, having an filtered air outlet duct 33 which extends through an aperture lib in the chin region of the helmet shell 11 and communicates with two ducts 34 and 35 within the helmet shell 11 and which open through the annular seal 14 to the volume VI.
• the air outlet duct 33 includes a radial flange 33a_ and that part of the duct 33 outwardly of the flange 33a is threaded to receive a nut 36.
• a shaped packing 37 lies between the flange 33 and the external surface of the helmet 11 surrounding the aperture lib and a shaped packing 38 lies between the nut 36 and the helmet shell 11 immediately surrounding the aperture lib internally of the helmet shell 11.
• the packing pieces 37 and 38 are shaped, on those faces presented to the helmet shell 11 surrounding the aperture lib, as to conform with the shape and configuration of the respective helmet shell areas engaged by the said packing pieces 37 and 38 whereby, when the nut 34 is tightened to secure the air outlet 30 to the helmet shell 11, the said shell 11 is not stressed by the securement of the outlet duct 33.
• the air outlet duct 33 from the filter arrangement 32 includes a valve 39, which is a pressure sensitive valve, arranged to open to allow filtered air to flow from the filter arrangement 32 through the air outlet duct 33 to the ducts 34 and 35, and therefrom to the volume VI, only whilst the pressure in volume in VI is less than the pressure of the surrounding atmosphere.
• a valve 39 which is a pressure sensitive valve, arranged to open to allow filtered air to flow from the filter arrangement 32 through the air outlet duct 33 to the ducts 34 and 35, and therefrom to the volume VI, only whilst the pressure in volume in VI is less than the pressure of the surrounding atmosphere.
• the valve 31 When the wearer is in an atmosphere capable of being filtered by the filter arrangement 27 to provide breathable air the valve 31 is closed and as the- wearer inhales, reducing the pressure in volume V2, air flows from the volume VI through the one-way valves 26 in the nose cone 24 and is inhaled by the wearer.
• the air flow from volume VI to volume V2 reduces the pressure in the volume VI below atmospheric pressure and the valve 39 opens to allow air to flow through the filter arrangement 32 and through outlet duct 33 and the ducts 34 and 35 to the volume VI.
• the valves 26 close and the exhalation valve 25 opens to discharge the spent air therethrough to the surrounding atmosphere.
• the wearer When now the wearer is to enter an environment wherein the filter, cannot supply breathable air to the volume VI the wearer opens the valve 31, thus connecting the reservoir 29 to the demand valve 28, and reservoir air flows from the reservoir 29 through the valve 28 and the duct 27 to the volume VI and, with the demand valve 26 set to supply air to the volume VI to maintain the volume VI at a pressure in excess of atmospheric pressure, the pressure in volume VI is extended via ducts 34 and 35 to the air outlet duct 33 to cause the valve 39 to close, thus closing the air passage between the filter arrangement 32 and the ducts 34 and 35.
• the wearer can then enter the hostile atmosphere, breathing only air supplied from the air reservoir 29, and on leaving the said hostile atmosphere and re-entering the filterable atmosphere the wearer can close the valve 31 to terminate the supply of air from the reservoir 29 and, as the pressure in the volume VI falls below the pressure of the surrounding atmosphere, the valve 39 will automatically open and the wearer will again breath air supplied through the filter 32 to the volume VI.
• a person wearing the safety helmet in accordance with the invention can wear the helmet in a breathable or filterable atmosphere without use of the air stored in the reservoir.
• the wearer can readily switch to the reservoir air supply by simply opening the valve 31, without removing the helmet and thereby without requiring access to a "safe" atmosphere and the wearer is thereby immediately ready to enter the adverse atmosphere.
• the wearer needs only to move out of the adverse atmosphere to a filterable atmosphere to exchange a used reservoir 29 for a charged reservoir 29, so that the wearer can move back into the adverse atmosphere with the minimum delay.
• the filter arrangement 32 is detachably connected to the filtered air duct 33 to allow the filter arrangement 32 to be interchangeable with other filter arrangements 32. Further, with this facility, when the wearer is on standby in a breathable atmosphere the filter arrangement
• valve 32 can be disconnected from the duct 32 and, with the valve 31 closed, the wearer is supplied with atmospheric air through the valve 39 and ducts 34 and 35. Immediately the wearer opens the valve 31, pressure air is supplied to the volume VI, the valve

Landscapes

• Health & Medical Sciences (AREA)
• Pulmonology (AREA)
• General Health & Medical Sciences (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Helmets And Other Head Coverings (AREA)
• Respiratory Apparatuses And Protective Means (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10686429

Family Applications (1)

Country Status (8)

Cited By (1)

Citations (4)

• 1990
  • 1990-12-04 GB GB909026311A patent/GB9026311D0/en active Pending
• 1991
  • 1991-11-27 WO PCT/GB1991/002097 patent/WO1992010237A1/en not_active Ceased
  • 1991-11-27 AU AU89409/91A patent/AU8940991A/en not_active Abandoned
  • 1991-12-02 ZA ZA919486A patent/ZA919486B/xx unknown
  • 1991-12-03 IN IN886MA1991 patent/IN180245B/en unknown
  • 1991-12-04 CN CN91112799A patent/CN1063049A/zh active Pending
  • 1991-12-04 NZ NZ240850A patent/NZ240850A/en unknown
  • 1991-12-04 MX MX9102372A patent/MX9102372A/es not_active Application Discontinuation

Patent Citations (4)

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