EP0413555A1 - Überdruckatemgerät - Google Patents

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Publication number
EP0413555A1
EP0413555A1 EP90308926A EP90308926A EP0413555A1 EP 0413555 A1 EP0413555 A1 EP 0413555A1 EP 90308926 A EP90308926 A EP 90308926A EP 90308926 A EP90308926 A EP 90308926A EP 0413555 A1 EP0413555 A1 EP 0413555A1
Authority
EP
European Patent Office
Prior art keywords
pressure
protective means
breathing apparatus
face mask
positive pressure
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.)
Withdrawn
Application number
EP90308926A
Other languages
English (en)
French (fr)
Inventor
Keith Simpson
Simon Kugler
James Alexander Hammerton-Fraser
Beverley Aleck Hinchliffe
Andrew Richard Thomas Tatarek-Gintowt
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.)
Sabre Safety Ltd
Original Assignee
Sabre Safety Ltd
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 Sabre Safety Ltd filed Critical Sabre Safety Ltd
Publication of EP0413555A1 publication Critical patent/EP0413555A1/de
Withdrawn legal-status Critical Current

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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
    • A62B18/006—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 with pumps for forced ventilation

Definitions

  • This invention relates to positive pressure breathing apparatus.
  • a positive pressure greater than the ambient pressure is maintained within a protective device such as a face mask or a hood surrounding the respiratory passages of a wearer so that, if there is any leakage, the leakage will all be outward from the protective device thus providing a high degree of protection against the ingress of noxious fumes into the gas which the wearer of the apparatus is breathing.
  • the positive pressure is conventionally provided by means of an air mover such as a blower or a fan which delivers air through a filter to the interior of a face mask, helmet or hood.
  • the air mover which may be a battery-driven electrical device, removes from the wearer the need to overcome the resistance of the filter and so reduces the breathing effort required.
  • positive pressure breathing apparatus comprising protective means for surrounding the respiratory passages of a wearer thereof to exclude noxious atmospheric gases from the space within the protective means and adjacent to the said respiratory passages, air moving means for supplying breathable gas to the protective means, and an electric power source for driving the air moving means, characterised in that electronic control means is provided for effecting pulse width modulation of the power source in dependence on the gas pressure within the protective means whereby the rate of supply of breathable gas by the air moving means to the protective means is varied in accordance with the demands of the wearer.
  • the voltage applied to the air moving means is reduced without dissipating power from the electric battery.
  • a positive pressure breathing apparatus comprising protective means for surrounding the respiratory passages of a wearer thereof to exclude noxious atmospheric gases from the space within the protective means and adjacent to the said respiratory passages, air moving means comprising a fan and a motor for driving the fan to supply breathable gas to the protective means at a rate faster than the rate of leakage of gas from the protective means, and an electric battery for supplying power to the fan motor to drive the fan, characterised in that a pressure sensitive electronic module is provided for causing the power applied from the electric battery to the fan motor to be supplied as D.C. pulses, the width of the pulses being modulated in dependence on the pressure sensed within the protective means whereby the speed of the fan motor is regulated according to the demand of the wearer.
  • Breathing apparatus in accordance with the present invention may employ entirely electronic means for reducing the air flow into the protective means during the exhalation part and the rest part of the breathing cycle.
  • the pressure sensitive electronic module comprises a pressure transducer which produces an electrical output signal proportional to the instantaneous gas pressure within the protective means and a pulse generator for generating pulses, the width of the pulses being varied in inverse relation to the electrical output signal from the pressure transducer.
  • the electrical output signal is an analogue signal which is utilized in the pulse width modulation of the pulses generated by the pulse generator.
  • the electrical output signal from the pressure transducer to be in digital form and for the digital signal to be processed before being applied to control the power fed from the electric battery to the fan motor by pulse width modulation.
  • the pressure sensitive electronic module additionally includes means for giving a visible warning of an unusually low gas pressure within the protective means, said visible warning means being energised under control of the pressure sensitive electronic module.
  • the protective means is preferably a full face mask but it may also be either a hood or an orinasal mask.
  • FIG. 1 of the accompanying drawings there is indicated diagrammatically a full face mask 1, the interior of which, when used normally, is slightly over-pressurised with clean filtered air for breathing purposes.
  • the clean filtered air is delivered into the interior of the face mask 1 by a fan 2 which is driven by an electric motor 3 which consumes a low voltage D.C. current from an electric battery 4.
  • Breathing air is drawn from the interior of the face mask 1 by the wearer's lung depicted diagrammatically at 5.
  • the face mask 1 additionally includes an inhale valve 6 and a exhale valve 7.
  • the itihale valve 6 closes down the output from the fan 2 when the pressure within the face mask 1 rises to a level in excess of the pressure of gas delivered from the fan 2.
  • the inhale valve 6 also ensures that no discharge from the interior of the face mask 1 occurs as a contra-flow through the fan 2 and the filter (not shown).
  • the exhale valve 7 is biased to the closed position in order to promote the build-up of a positive pressure above the ambient atmospheric pressure within the interior of the face mask 1.
  • the exhale valve 7 will open at a predetermined positive pressure within the face mask 1 and allows the essential discharge of exhaled gases and extraneous air delivered by the fan from the interior of the face mask 1 to the surrounding atmosphere.
  • a pressure sensitive electronic module 8 Positioned within the interior of the face mask 1 is a pressure sensitive electronic module 8 which may be a specially designed electronic chip. Module 8 performs the essential function in accordance with the present invention of sensing the pressure within the interior of the face mask 1 and providing D.C. pulses from the electric battery 4 to the fan motor 3, the width of the pulses being chosen as a result of the sensing of the pressure within the face mask 1 to cause the fan 2 to supply air to the interior of the face mask 1 at a rate to meet the demand of the wearer while maintaining a positive pressure within the interior of the face mask 1.
  • the operation of the pressure sensitive electronic module 8 will be further described in relation to Figure 2 of the accompanying drawings.
  • a light emitting diode 9 is secured to a rigid part of the face mask 1, for example a part of the visor assembly, in order to provide a visible warning to the wearer of the face mask 1 that the gas pressure within the face mask 1 is falling to an unusually low level, indicating an unsatisfactory performance and the need for the wearer to take prompt action to withdraw from the noxious atmosphere.
  • the unsatisfactory performance may be due to the electric battery nearing the end of its useful life or to the filter becoming blocked or to part of the face mask 1 no longer providing a proper seal.
  • the light emitting diode 9 is energised to give the visible warning to the wearer by a threshold circuit within the pressure sensitive electronic module 8.
  • the module 8 effectively comprises a pressure transducer which produces an electrical voltage output signal proportional to the instantaneous gas pressure in the interior of the face mask 1 and a control circuit including a pulse generator.
  • the pressure transducer may be a piece of silicon having a Wheatstone bridge thereon and, as the gas pressure within the face mask 1 changes the silicon flexes with the result that the resistance in the arms of the Wheatstone bridge change and a variable voltage output is given.
  • the pressure transducer thus performs steps 11 and 12 of Figure 2.
  • Step 15. - The modified signal is converted into pulses of width proportional to the voltage at a frequency high enough for the flux not to die down in the motor windings between pulses. Advantageously a pulse frequency of the order of 16 kilohertz or higher is used.
  • Step 16. - The signal from the pulse generator of Step is used to drive a power transistor which switches the power to the fan motor 3 at instants and for periods determined by the widths of the pulses.
  • the motor speed will be changed speedily in response to a change in pressure within the face mask 1 sensed by the pressure transducer.
  • the change in motor speed leads to another change in pressure which in turn is picked up by the pressure transducer and fed back by the electronic module 8 thereby providing continuous adjustment of the speed of the fan 2 to changes of pressure within the face mask 1 and matching the flow of air into the face mask 1 to the requirements of the wearer whilst maintaining a substantially constant pressure in the face mask.
  • the fan speed during inhalation will be set according to the work rate of the wearer, faster, deeper breathing at a high work rate leading to a higher fan speed than slow breathing by a wearer who has just donned the breathing apparatus and has not started energetic physical movement.
  • the fan speed is responsive solely to the gas pressure within the face mask or other protective means, and is not affected, as happens in some prior proposals, by unpredictable conditions within the face mask, such as air flow patterns around a diaphragm or a flap valve.
  • the pressure sensitive electronic module may be arranged in any position, within or outside the face mask or other protective means, from which the pressure within the face mask can be sensed.
  • the operation of the apparatus according to the present invention is not adversely affected by a failure of the wearer correctly to don the protective means. Also the pressure sensitive electronic means is resistant to impact shock and to vibration.
  • the pressure sensitive electronic module of positive pressure breathing apparatus has no moving parts or mechanical switching of electrical contacts and hence has improved reliability of performance.
  • control chip of the pressure sensitive electronic module may readily accommodate threshold settings adaptable to provide indications of potential failures.

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)
EP90308926A 1989-08-18 1990-08-14 Überdruckatemgerät Withdrawn EP0413555A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8918901A GB2235136A (en) 1989-08-18 1989-08-18 Positive pressure breathing apparatus
GB8918901 1989-08-18

Publications (1)

Publication Number Publication Date
EP0413555A1 true EP0413555A1 (de) 1991-02-20

Family

ID=10661845

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90308926A Withdrawn EP0413555A1 (de) 1989-08-18 1990-08-14 Überdruckatemgerät

Country Status (2)

Country Link
EP (1) EP0413555A1 (de)
GB (1) GB2235136A (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0528733A1 (de) * 1991-08-21 1993-02-24 Intertechnique Giftstoffatemschutzausrüstung
DE4201832A1 (de) * 1992-01-24 1993-07-29 Draegerwerk Ag Atemschutzmaske mit stroemungsanzeiger fuer die atemluft
EP0621056A1 (de) * 1993-04-14 1994-10-26 Msa (Britain) Limited Atemschutzgerät
WO1998031282A1 (de) * 1997-01-17 1998-07-23 Messer Griesheim Austria Ges.Mbh Gesteuertes gasversorgungssystem
DE102010022784A1 (de) * 2010-06-04 2011-12-08 Tesimax-Altinger Gmbh Schutzanzug mit Atemluftversorgungseinrichtung
EP2486959A4 (de) * 2009-10-07 2015-12-09 Shigematsu Works Atmungsunterstützungsvorrichtung
US9950197B2 (en) 2013-04-20 2018-04-24 Dräger Safety AG & Co. KGaA Blower filter device
DE102015003385B4 (de) 2015-03-17 2018-07-19 Dräger Safety AG & Co. KGaA Gebläsefilteratemsystem

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI100307B (fi) * 1994-02-25 1997-11-14 Kemira Safety Oy Menetelmä kaasunaamariin syötetyn ilmamäärän säätämiseksi sekä kaasuna amari
CN112998992A (zh) * 2021-02-09 2021-06-22 北京机械设备研究所 一种正压防护系统控制方法、装置、介质及电子设备

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2032284A (en) * 1978-10-02 1980-05-08 Racal Safety Ltd Improvements in and relating to breathing apparatus
EP0066451A1 (de) * 1981-05-29 1982-12-08 Racal Safety Limited Atemgerät mit motorunterstützter Luftreinigung
US4765326A (en) * 1987-04-20 1988-08-23 Minnesota Mining And Manufacturing Company Low-flow alarm system for powdered air-purifying respirator
US4856078A (en) * 1988-03-23 1989-08-08 Zenith Electronics Corporation DC fan speed control

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1104849A (en) * 1965-10-18 1968-02-28 Westland Aircraft Ltd Improvements in or relating to oxygen regulators
GB2215615B (en) * 1988-03-21 1991-12-18 Sabre Safety Ltd Breathing apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2032284A (en) * 1978-10-02 1980-05-08 Racal Safety Ltd Improvements in and relating to breathing apparatus
EP0066451A1 (de) * 1981-05-29 1982-12-08 Racal Safety Limited Atemgerät mit motorunterstützter Luftreinigung
US4765326A (en) * 1987-04-20 1988-08-23 Minnesota Mining And Manufacturing Company Low-flow alarm system for powdered air-purifying respirator
US4856078A (en) * 1988-03-23 1989-08-08 Zenith Electronics Corporation DC fan speed control

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0528733A1 (de) * 1991-08-21 1993-02-24 Intertechnique Giftstoffatemschutzausrüstung
FR2680467A1 (fr) * 1991-08-21 1993-02-26 Intertechnique Sa Equipement de protection respiratoire contre les polluants.
US5318020A (en) * 1991-08-21 1994-06-07 Intertechnique Equipment for respiratory protection against pollutants
DE4201832A1 (de) * 1992-01-24 1993-07-29 Draegerwerk Ag Atemschutzmaske mit stroemungsanzeiger fuer die atemluft
EP0621056A1 (de) * 1993-04-14 1994-10-26 Msa (Britain) Limited Atemschutzgerät
US7861717B1 (en) 1997-01-17 2011-01-04 Ino Therapeutics Gmbh Controlled gas-supply system
WO1998031282A1 (de) * 1997-01-17 1998-07-23 Messer Griesheim Austria Ges.Mbh Gesteuertes gasversorgungssystem
EP2486959A4 (de) * 2009-10-07 2015-12-09 Shigematsu Works Atmungsunterstützungsvorrichtung
DE102010022784A1 (de) * 2010-06-04 2011-12-08 Tesimax-Altinger Gmbh Schutzanzug mit Atemluftversorgungseinrichtung
EP2407208A1 (de) 2010-06-04 2012-01-18 Tesimax - Altinger GmbH Schutzanzug mit Atemluftsversorgungseinrichtung
US9950197B2 (en) 2013-04-20 2018-04-24 Dräger Safety AG & Co. KGaA Blower filter device
DE102013006915B4 (de) 2013-04-20 2018-07-19 Dräger Safety AG & Co. KGaA Gebläsefiltergerät
DE102015003385B4 (de) 2015-03-17 2018-07-19 Dräger Safety AG & Co. KGaA Gebläsefilteratemsystem
US10625103B2 (en) 2015-03-17 2020-04-21 Dräger Safety AG & Co. KGaA Blower filter respirator system

Also Published As

Publication number Publication date
GB8918901D0 (en) 1989-09-27
GB2235136A (en) 1991-02-27

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