Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
  • A62B7/00—Respiratory apparatus
  • A62B7/12—Respiratory apparatus with fresh-air hose

Definitions

• the present invention relates to breathing equipment of the kind which includes a breathing mask, a breathing hood or the 4 5 like, and conduit means for delivering breathing gas to the mask or hood.
• ma ⁇ k is meant here both full face masks that are provided with a viewing visor, and so-called half masks which cover
• breathing hood includes, among other things, so-called
• breathing gas is 20 supplied to the space delimited by the ma ⁇ k or hood. If a fault ⁇ hould occur ⁇ o that the ⁇ upply of breathing gas ceases or becomes insufficient, for instance as a result of a mechanical fault in the equipment or because the ⁇ upply of breathing gas has been exhausted, no fresh gas will be 25 supplied to the wearer of the equipment. As a result, the carbon dioxide content of the available breathing air will build-up while the oxygen content diminishes at the same time, which can quickly lead to suffocation.
• the main object of the present invention i ⁇ to provide breathing equipment of the afore ⁇ aid kind which in the event of a malfunction in the breathing ga ⁇ ⁇ upply will auto ati- cally open a connection between the interior of the mask or hood and the ⁇ urrounding atmo ⁇ phere so a ⁇ to enable this atmosphere to be breathed by the wearer of the ma ⁇ k or hood.
• Thi ⁇ object i ⁇ achieved with breathing equipment of the kind which i ⁇ defined in the first paragraph and which i ⁇ charac ⁇ terized in accordance with the invention by a valve mean ⁇ which is normally closed in use and which when open connects the space delimitated by the mask or by the hood with the surrounding atmosphere, therewith to enable this atmosphere to be breathed, and by mean ⁇ for detecting when the ⁇ upply of breathing ga ⁇ to the ma ⁇ k or hood ha ⁇ fallen beneath a given level and for opening the valve means in accordance therewith.
• valve means i ⁇ a pre ⁇ sure-controlled valve adapted to open when the pressure in the breathing gas conduit ha ⁇ fallen beneath a predetermined value.
• the valve mean ⁇ may conveniently include a spring- biassed valve body which is pressed sealingly against a valve seat when the conduit pressure exceeds said value, but which is moved away from the seat by spring force when the pressure falls beneath said value.
• the valve body has the form of a spring-loaded valve plate which is actuated directly by the pressure of the breathing ga ⁇ .
• the plate is dispo ⁇ ed in a hou ⁇ ing which i ⁇ intended to be fitted over an opening in the ma ⁇ k or hood and which includes a chamber that communicates with the breathing gas conduit and whose one wall is comprised either completely or partially of said plate, which closes the opening when the pre ⁇ ure prevailing in the chamber i ⁇ ⁇ ufficient to this end.
• Passageways are provided which connect the interior of the mask or hood with the surrounding atmosphere when the plate is moved away from the opening.
• Fig. 1 is a schematic illustration of a so-called escape hood supplemented with an inventive arrangement
• Fig. 2 illustrates schematically an exemplifying embodiment of the inventive arrangement.
• Fig. 1 illustrates a so-called escape hood 1 which is con ⁇ nected to a breathing gas container (not shown) by means of a conduit 2.
• a hood of this kind can be used temporarily, for instance, to protect against smoke and gases in an emergency, for instance in the case of fire, gas leakages from gas pipes, or in toxic gas environments created by chemicals.
• a throttle means 14 in the conduit 2 As breathing gas flows through the conduit, a throttle means 14 in the conduit 2 generates an overpressure therein.
• a valve means 4 is connected so as to be actuated by the gas pressure in the conduit 2.
• the wearer breathes gas flowing from the conduit 2 into the hood 1 via an inlet 3.
• the wearer is able to breathe the surrounding atmo ⁇ sphere when the supply of breathing gas ceases or has fallen to beneath a given value. This is a better alternative than breathing the exhalation air under any circumstance. Inhala ⁇ tion of exhalation air would quickly result in ⁇ uffocation. The danger of the surrounding atmosphere being immediately fatal is very small in many cases.
• Fig. 2 illustrates an embodiment of an inventive valve means in more detail, wherein those components that find correspon- dence in Fig. 1 have been identified by the same reference signs.
• Reference numeral 1 thus identifies part of the wall of a hood shown in Fig. 1.
• the wall has provided therein an opening 6 which is held clo ⁇ ed by a valve plate 8 in normal u ⁇ e condition ⁇ .
• the plate 8 form ⁇ one wall of a chamber 9 in a housing 10 mounted on the hood 1.
• the chamber 9 communi ⁇ cates with the breathing gas supply conduit 2, so that the pressure in the conduit 2 will act directly on the plate 8 and a diaphragm 12.
• the pressure in the conduit 2 may correspond to an overpressure of about 0.1-0.2 bar for instance, which is sufficient to hold the valve plate 8 in sealing abutment with the defining edges of the opening 6.
• valve plate 8 If the pressure in the conduit 2 falls beneath a predetermined value, the valve plate 8 will be moved away from the edges of the opening 6 in re ⁇ ponse to the force exerted by a pres ⁇ ure ⁇ pring 11 mounted around the opening. Thi ⁇ movement of the plate 8 i ⁇ enabled by a flexible diaphragm 12 of the so-called roll diaphragm type fitted to the housing 10.
• the interior of the hood 1 communicates with the surrounding atmo ⁇ phere through openings 13 in the housing 10, these openings corresponding to the outlet and inlet 7 shown in Fig. 1.
• the wearer i ⁇ then able to breath the ⁇ urrounding atmo ⁇ phere freely.
• the openings 13 may, of course, be provided with suitable filter means.
• the valve means can be constructed to open at a desired pressure level in the conduit 2, by appropriate choice of the area of the valve plate 8 and the force of the spring 11.
• the inventive arrangement can al ⁇ o be u ⁇ ed in a full face ma ⁇ k or a so-called half mask.
• the illustrated and described embodiment has been chosen merely to describe the principle of the invention in a simple manner.
• the design and attach ⁇ ment of the arrangement can be varied as desired within the scope of the Claims.
• the conduit 2 can be connected to the chamber 9 so that all breathing gas will pass through the chamber before being delivered to the hood or mask.
• valve means can also be varied in several respects while maintaining its function of control ⁇ ling the supply of breathing gas, such that the valve will automatically open the connection between the interior of the hood or the mask and the surrounding atmo ⁇ phere when nece ⁇ ary, without requiring the wearer to perform any action in this regard, which is a central characteristic feature of the inventive arrangement.
• valve means may alternatively be mounted on the inside of the hood or mask and comprise an inwardly opening valve body.
• the pre ⁇ ure ⁇ pring may, of course, be replaced with a pull spring when wishing to place the spring on the other side of the plate 8, for instance.
• sensing the pre ⁇ ure in the conduit 2 it is also possible to use means which sense the flow of breathing gas and to initiate automatic opening of the valve means when the rate of flow is low or non-existent.

Landscapes

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

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20398858

Family Applications (1)

Country Status (6)

Cited By (2)

Citations (2)

Family Cites Families (3)

• 1995
  • 1995-07-05 SE SE9502439A patent/SE511288C2/sv unknown
• 1996
  • 1996-06-27 EP EP96923136A patent/EP0956100B1/de not_active Expired - Lifetime
  • 1996-06-27 WO PCT/SE1996/000852 patent/WO1997002070A1/en active IP Right Grant
  • 1996-06-27 AU AU63728/96A patent/AU711329B2/en not_active Ceased
  • 1996-06-27 CA CA 2226099 patent/CA2226099A1/en not_active Abandoned
  • 1996-06-27 DE DE69623353T patent/DE69623353T2/de not_active Expired - Fee Related

Patent Citations (2)

Also Published As

Similar Documents

Legal Events