EP0241188A1 - Atemschutzgeräte - Google Patents

Atemschutzgeräte Download PDF

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Publication number
EP0241188A1
EP0241188A1 EP87302680A EP87302680A EP0241188A1 EP 0241188 A1 EP0241188 A1 EP 0241188A1 EP 87302680 A EP87302680 A EP 87302680A EP 87302680 A EP87302680 A EP 87302680A EP 0241188 A1 EP0241188 A1 EP 0241188A1
Authority
EP
European Patent Office
Prior art keywords
face mask
inlet
outlet
pressure
pump
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Withdrawn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
EP87302680A
Other languages
English (en)
French (fr)
Inventor
Joseph Raymond Hilton
Paul Robert Rabin
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.)
Racal Safety Ltd
Original Assignee
Racal 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 Racal Safety Ltd filed Critical Racal Safety Ltd
Publication of EP0241188A1 publication Critical patent/EP0241188A1/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Withdrawn legal-status Critical Current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

  • the present invention relates to improved breathing apparatus and is concerned with the types of breathing apparatus known as powered air purifying respirators (PAPRs) and compressed air breathing apparatus (CABA).
  • Both types of breathing apparatus include a face mask for the wearer which is provided with an inlet to which air to be breathed by the wearer is supplied.
  • the air of PAPRs is ambient air which is pumped to the face mask by a battery powered pump carried by the wearer, the air being filtered downstream, or more generally upstream, of the pump.
  • the air for CABA is compressed air, provided either from a com­pressed air line or a local source of compressed air, e.g. a cylinder which may be carried by the wearer, and which is supplied to the face mask via a pressure controlled or demand valve assembly.
  • Positive pressure versions of both types of breathing apparatus are available, in which the pressure of air within the face mask is maintained at a pressure above ambient pressure by providing in the outlet of the face mask an outlet or exhale valve which will only open when the pressure in the face mask is at a preset level above the ambient pressure.
  • Such positive pressure versions of the above types of breathing apparatus are used, for example, where a worker is operating in a hazardous environment.
  • a positive pressure breathing apparatus may be required at all times.
  • a worker may wear a positive pressure CABA supplied with compressed air from a cylinder and in accordance with British Standard No. 4667 part 2; 1974 "Open-circuit breathing apparatus", but the short duration (approximately one hour) and weight (10 kg) of the cylinder renders this of limited use.
  • the worker will be provided with a positive pressure CABA supplied from a compressed air line and in accordance with British Standard No. 4667 part 3; 1974 "Fresh-air hose and compressed air line breathing apparatus".
  • a major disadvantage of air line supplied breathing apparatus is apparent when two or more workers are working in close proximity and the air lines become entangled. The air lines are also themselves vulnerable to damage. Additionally, a supply of compressed air to the work site is also necessary.
  • An alternative breathing apparatus is a positive pressure PAPR in accordance with BS 4558; 1970 "Positive pressure, powered dust respirators”. While such a breathing apparatus confers mobility on the worker and has a high standard of filtration, towards the end of the working period, the apparatus may suffer from a reduced air flow due to the clogging of the filter with dust or due to a reduced battery voltage. This is characterised by a reduction in the pressure of air supplied to the face mask and possibly the intermittent appearance of pressures within the face mask below ambient pressure. Such an apparatus thus fails to meet the requirement of positive pressure within the face mask at all times and may therefore require the incorporation of a device to warn of the onset of "failure". Such a warning device is difficult to calibrate and may be unreliable in use.
  • the pressure within the face mask may intermittently fall below ambient pressure if the breathing rate of the wearer becomes abnormally high, for example, as a result of a high degree of exertion by the wearer.
  • the breathing rate is often denoted by the Minute Volume (Vm), i.e. the amount of air breathed per minute, which is the product of the number of respirations per minute and the tidal volume (Vt).
  • Vm Minute Volume
  • the maximum instantaneous rate (assuming sinusoidal breathing) is approximately three times the Minute Volume. It can be seen that for a man working moderately hard for whom Vm equals 50 litres, the apparatus must supply more than 150 l/min. A Minute Volume of 60 litres requires a supply of 180 l/min. etc.
  • a positive pressure CABA is normally arranged to supply up to 350 l/min and a positive pressure PAPR is normally arranged to supply up to 200 l/min, but with both sub­ambient pressure within the face mask can occur due to the inertial effects of the demand valve in the case of the CABA and pump restrictions in the case of the PAPR.
  • a breathing apparatus which is in effect and normally operates as a positive pressure PAPR but which is combined with a positive pressure CABA with the face mask exhale valve and the demand valve of the CABA adjusted relative to each other and to the operation of the pump of the PAPR so that the demand valve of the CABA will open only when the pressure in the face mask drops below a preset minimum level, which is not achieved during normal operation of the apparatus, to ensure that a positive pressure is at all times maintained in the face mask.
  • breathing apparatus comprising a face mask for covering the nose and mouth of the wearer and having inlet means and outlet means for gas, the outlet means being provided with non-­return outlet valve means adapted for maintaining a positive differential pressure within the face mask, the face mask inlet means being connected to the outlet of pump and filter means for supplying filtered ambient air to the face mask, said face mask inlet means also being connected to the outlet of controllable valve means having an inlet for connection to the supply of pressurised breathable gas, and a pressure sensitive control means for controlling the controllable valve means and adapted to cause opening of the controllable valve means in the event that the pressure in the face mask falls below a preset minimum relative to ambient pressure which is such that under normal operating conditions the controllable valve means remains closed, filtered ambient air being supplied to the face mask by the pump and filter means.
  • the control means may be arranged to cause closing of the controllable valve means when the pressure within the face mask rises above a preset level above said preset minimum level.
  • Figure 1 (a) shows the pressure within the face mask of a conventional negative inspiration or unpowered respirator or CABA without positive pressure, under conditions of normal use.
  • the pressure shown on the y axis, varies between positive and negative relative to ambient pressure, which is represented by O, depending on whether the wearer is exhaling or inhaling.
  • Figure 1 (b) shows the pressure within the face mask of a positive pressure PAPR or positive pressure CABA under normal conditions and in which the pressure is in effect lifted wholly above ambient pressure (O), and the pressure within the face mask does not, in normal use, fall below ambient pressure.
  • Figure 1 (c) shows what can happen, for example if the wearer increases exertion or, in the case of a PAPR, the filter becomes clogged or the battery begins to fail. Insufficient air is supplied to the face mask so that, at the peak of inhalation, the pressure within the face mask dips below ambient pressure (O).
  • Figure 2 shows diagrammatically an embodiment according to the present invention comprising a face mask 1 for covering at least the mouth and nose of the wearer and which is provided with inlet means 2 and and outlet 3.
  • the outlet 3 is provided with a non-­return outlet valve 4 which is biassed, for example by a spring, to open only when the pressure within the face mask exceeds ambient pressure by a preset amount.
  • Inlet means 2 may, as shown, be provided with a non-­return valve 5, as is conventional, to prevent reverse flow of air through the inlet, but this valve may be dispensed with.
  • the face mask inlet means 2 is connected to two breathable gas supply systems in parallel.
  • the system comprises pump and filter means which draws in ambient air and pumps it to the inlet means of the face mask.
  • the pump may, as shown, comprise a fan 6, which may be an axial fan or, as illustrated, a centrifugal fan, which is driven by a battery operated motor (not shown).
  • the inlet 7 of the pump unit is connected to the outlet 8 of the filter unit 9 whose inlet 10 is open to ambient air so that the fan 6 draws ambient air in through the filter and expels it into the outlet 11 of the fan which is connected by a non-return valve 12 to the face mask inlet means.
  • the system comprises a controllable valve assembly 13 having an inlet 14 which is connected to a supply of compressed air (not shown), for example as is used for CABA, by a flexible hose 15, and an outlet 16 which is connected by an optional non-return valve 17 to the face mask inlet means 2.
  • the valve assembly 13 comprises a tiltable controllable valve member 18 arranged to control communication between inlet 14 and outlet 16 and which is controlled by a pressure sensitive device within assembly 13 and which senses the difference in pressure between ambient pressure and the pressure in the assembly outlet, which is effectively the same as the pressure in the face mask.
  • the pressure sensing device may, as shown, comprise a diaphragm 19 arranged with one face exposed to ambient pressure and the other face exposed to the pressure within the assembly outlet and which is biassed by a spring 20. Movements of the diaphragm 19 are transmitted by a transmission mechanism to the valve member 18 to cause tilting of the valve member.
  • the differential pressure at which the valve member 18 will open is set by appropriate adjustment or selection of the bias on the diaphragm which is also arranged so that, after opening, the valve member 18 will be closed when the pressure in the outlet of assembly 13 has risen by a preset amount above the pressure at which the valve member opened.
  • the differential pressure within the assembly outlet is arranged to be less than that at which the outlet valve (4) in the face mask outlet closes and in effect represents a minimum differential pressure which is to be maintained at all times within the face mask.
  • the fan 6 is arranged to operate at a rate sufficient to maintain the required positive pressure in the face mask for normal operating conditions, and the bias on the exhale valve and the bias on the diaphragm 19 are adjusted relative thereto to ensure that, under normal operating conditions, the valve member 18 remains closed so that the air required by the wearer ofthe face mask is provided solely by the fan 6, i.e. the apparatus operates as a positive pressure PAPR. If however, the pressure of the air supplied by the fan 6 reduces, due to clogging of the filter or reducing battery voltage, or if the wearer's breathing rate increases to an abnormal level, then at least during inhalation by the wearer, the pressure within the face mask will fall.
  • valve member 18 If it falls to the pressure relative to ambient pressure at which the valve member 18 opens, then compressed air will be supplied through assembly 13 to the face mask to increase the pressure within the face mask to thereby ensure that it does not fall further and specifically does not fall below ambient pressure. Supply of compressed air through assembly 13 will continue until the pressure in the face mask rises by the preset amount determined by the bias of spring 20. At this point, valve member 18 will close and the supply of air to the face mask by pump 16 will be resumed.
  • non-return valve 12 will close to prevent reverse flow of air through the pump 6 and filter 9 and loss of pressure thereby.
  • any opening of valve 18 lasts only for a fraction of a second, and only occurs at the peak in inhalation by the wearer.
  • the period of each opening of valve 18 will progressively increase as clogging increases or battery voltage reduces and eventually the face mask may be supplied with breathable gas solely through assembly 13. Under these circumstances, the apparatus will operate like a CABA.
  • Figure 3 shows an embodiment of apparatus according to the present invention and specifically shows in greater detail the fan 6 and filter 9 shown diagrammatically in Figure 2, together with connection of the outlet of the fan 6 and of the valve assembly 13 to a mask.
  • the same reference numerals are used in Figure 3 as are used in Figure 2 for corresponding parts.
  • the apparatus shown in Figure 3 comprises a connector 21 having an outlet 22 optionally fitted with a conventional threaded coupling ring 23, for connection to the inlet boss of a conventional face mask (not shown in Figure 3).
  • the connector 21 is generally T-shaped and comprises a pair of coaxial inlets 24, 25 communicating with the outlet 22, each of which is provided with an insert 26 which is, optionally threaded to receive a conventional coupling ring 27, 28 similar to the ring 23 on outlet 22.
  • the non-return valves 12,17 as shown in the form of flexible disc valves, are advantageously mounted on the inserts 26.
  • Fan 6 is mounted, together with its motor 29, in a housing 30 defining the inlet 7 and the outlet 11 of the fan, and may for example be constructed as described in co-pending European Patent Application No. 0164946.
  • Coupling ring 27 is mounted on the outlet 11 of the fan, and, as described in the above referred to co-pending patent application, the inlet 7 is adapted, e.g. threaded, for engagement with the filter canister 9.
  • Coupling ring 28 is mounted on the part of the housing of assembly 13 defining the outlet 16 of the assembly.
  • non-return valve 17 is in fact superfluous and can be omitted. It may however be convenient to provide non-return valves on both of the inlets 24,25 of the connector assembly 21 so that the fan housing can be connected to either of the inlets of connector 21. In operation and while assembly 13 is closed, valve 17 will also be closed but it will in effect open and close with valve member 18.
  • Figures 4 and 5 show the apparatus of Figure 3 mounted on the face mask 1, in use.
  • the battery or batteries for powering the motor 29 are mounted in a housing connected by a lead 31 to the motor, the housing being provided with an on/off switch and arranged for location in a pocket in the wearer's clothing or attached to the wearer's belt as shown in Figure 5.
  • the compressed air supply connected to hose 15 is provided by a dedicated supply, e.g. a cylinder 33 which incorporates, as is conventional, a pressure regulator 34 and may for example be supported on a belt around the waist of the wearer, as shown in Figure 5, or across the small of the back of the wearer in a special jerkin.
  • a dedicated supply e.g. a cylinder 33 which incorporates, as is conventional, a pressure regulator 34 and may for example be supported on a belt around the waist of the wearer, as shown in Figure 5, or across the small of the back of the wearer in a special jerkin.
  • the housing including the fan and its motor is mounted directly on the face mask, it may alternatively, as shown in Figures 6 and 7, be connected to one of the inlets of connector 21 by a flexible hose 35, the housing 30 then being mounted on a harness or belt for example at the back of the wearer.
  • the housing 30 may have a plurality of inlets connected to the fan inlet, each of which can be provided with a filter canister 9.
  • valve assembly 13 including the pressure sensitive control means may take other forms than that shown in Figure 2 or described in United Kingdom Patent No. 2116852, and that the fan and motor may also take other forms.
  • a positive displacement pump may be used and under such circumstances, if the pump itself seals against return flow therethrough, non-return valve 12 may be omitted. It is however preferred that a non-positive displacement air moving means be used so that it will continue to rotate during opening of assembly 13 when non-return valve 12 is closed.
  • the levels of the biases on the mask outlet valve and on the diaphragm, or other pressure sensing means controlling valve 18, in relation to operation of the pump are critical to the effective and economic operation of the breathing apparatus.
  • the differential pressure at which it opens may be in the range of differential pressures normally used for CABA or less, for example of the order of the ranges normally used for PAPR.
  • the differential pressure at which the valve member 18 will open is however smaller than that normal for CABAs.
  • the exhale valve may under normal conditions of operation remain permanently open or may open and close with the breathing cycle of the wearer. If, under normal conditions of operation, the exhale valve remains permanently open, as the pressure maintained within the face mask drops towards the preset minimum, for whatever cause, the exhale valve will begin to close during inhalation.
  • An additional advantage of the above described apparatus is that it innately provides the wearer with an audible signal indicating that he is either overexerting himself or that the filter is becoming blocked or the battery is running down. Specifically, when the valve memer 18 opens, there is an audible hiss generated by the inlet of compressed air through the valve. If it is simply that the wearer's breathing rate is abnormally high, when he reduces his breathing rate the hiss will cease, the hiss in any event being intermittent.
  • the cylinder regulator 34 may be fitted with a whistle warning device of conventional type which is arranged to sound when approximately 80% of the cylinder capacity has been used up.
  • the face mask used in the above described embodiments is a conventional face mask comprising an outer mask covering the entire face of the wearer and an inner mask covering the nose and mouth of the wearer.
  • the face mask is provided with an inlet opening in the outer mask opening into the space between the masks, and an outlet provided with the exhale valve communicating with the space within the inner mask, communication between the spaces between and within the masks being provided by openings in the inner mask provided with non-return valves.
  • the apparatus described above may also be used with other conventional full or partial masks which cover at least the nose and mouth of the wearer and are provided with inlet and outlet means.
  • masks are known which are provided with two inlet openings.
  • the outlet of the assembly 13 is connected to one inlet and the outlet of the pump, or one end of the flexible hose (where provided) connected thereto, is connected to the other inlet via a non-­return valve (if required) which may be provided in the mask inlet or in the pump outlet.
  • a non-­return valve if required
  • the two mask inlets are identified by numerals 2a and 2b.
  • Each inlet is provided with a non-return valve which correspond to valves 12 and 17 respectively.
  • the pump unit and the filter unit are mounted directly on the face mask.
  • the pump unit may be connected to the inlet 2a by a flexible hose, as described above in relation to Figures 6 and 7.
  • the filter unit or units through which the ambient air is drawn by the pump in the above described embodiments may be designed to remove contaminants in the form of particulate materials and/or gases or vapours.

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  • Health & Medical Sciences (AREA)
  • Pulmonology (AREA)
  • General Health & Medical Sciences (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Respiratory Apparatuses And Protective Means (AREA)
EP87302680A 1986-04-03 1987-03-27 Atemschutzgeräte Withdrawn EP0241188A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB868608113A GB8608113D0 (en) 1986-04-03 1986-04-03 Breathing apparatus
GB8608113 1986-04-03

Publications (1)

Publication Number Publication Date
EP0241188A1 true EP0241188A1 (de) 1987-10-14

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ID=10595592

Family Applications (1)

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EP87302680A Withdrawn EP0241188A1 (de) 1986-04-03 1987-03-27 Atemschutzgeräte

Country Status (2)

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EP (1) EP0241188A1 (de)
GB (1) GB8608113D0 (de)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0464234A1 (de) * 1990-07-02 1992-01-08 Kernforschungszentrum Karlsruhe Gmbh Atemluftversorgungsgerät
US5318019A (en) * 1992-03-19 1994-06-07 Celaya Marty A Emergency portable oxygen supply unit
US5372130A (en) * 1992-02-26 1994-12-13 Djs&T Limited Partnership Face mask assembly and method having a fan and replaceable filter
EP0736309A1 (de) * 1995-01-06 1996-10-09 Pai-Her Mou Lebensrettende Beatmungsvorrichtung
WO2002066105A1 (en) * 2001-02-16 2002-08-29 Resmed Ltd. Methods and apparatus for supplying clean breathable gas
US7380551B2 (en) 2003-03-21 2008-06-03 Tvi Corporation Breathing apparatus
WO2008068545A1 (en) * 2006-12-05 2008-06-12 Intertechnique A respiratory gas supply circuit to feed crew members and passengers of an aircraft with oxygen
US7647927B2 (en) 2003-08-22 2010-01-19 Wilcox Industries Corp. Self-contained breathing system
EP2292291A3 (de) * 2003-08-15 2014-08-13 Shahar Hayek Beatmungsgerät
WO2016157159A1 (en) * 2015-04-03 2016-10-06 Microsfere Pte. Ltd. Respiratory masks, systems and methods
DE102016009486B4 (de) * 2015-09-03 2021-01-07 Dräger Safety AG & Co. KGaA Gebläsefiltersystem und Kopfstückmonitoreinheit in einem solchen Gebläsefiltersystem
CN112618984A (zh) * 2021-01-11 2021-04-09 淮南安裕机电科技有限责任公司 一种滤尘送风式防尘口罩
EP3915644A1 (de) * 2020-05-27 2021-12-01 Honeywell International Inc. Kompakte beatmungsanordnung
US11291869B2 (en) 2017-11-15 2022-04-05 Immediate Response Technologies, Llc Modular powered air purifying respirator system

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR814750A (fr) * 1935-12-12 1937-06-28 Perfectionnement dans la construction des masques anti-gaz
US2284054A (en) * 1941-09-09 1942-05-26 Hermann Siegwart Gas mask
US3202150A (en) * 1962-06-11 1965-08-24 Scott Aviation Corp Filter attachment for a pressurized breathing apparatus
GB1587812A (en) * 1967-03-20 1981-04-08 Secr Defence Respirators
EP0094757A2 (de) * 1982-05-13 1983-11-23 Racal Safety Limited Atemschutzgerät
DE3512644A1 (de) * 1985-04-06 1986-10-16 Bartels & Rieger GmbH & Co, 5000 Köln Atemschutzgeraet

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR814750A (fr) * 1935-12-12 1937-06-28 Perfectionnement dans la construction des masques anti-gaz
US2284054A (en) * 1941-09-09 1942-05-26 Hermann Siegwart Gas mask
US3202150A (en) * 1962-06-11 1965-08-24 Scott Aviation Corp Filter attachment for a pressurized breathing apparatus
GB1587812A (en) * 1967-03-20 1981-04-08 Secr Defence Respirators
EP0094757A2 (de) * 1982-05-13 1983-11-23 Racal Safety Limited Atemschutzgerät
DE3512644A1 (de) * 1985-04-06 1986-10-16 Bartels & Rieger GmbH & Co, 5000 Köln Atemschutzgeraet

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0464234A1 (de) * 1990-07-02 1992-01-08 Kernforschungszentrum Karlsruhe Gmbh Atemluftversorgungsgerät
US5372130A (en) * 1992-02-26 1994-12-13 Djs&T Limited Partnership Face mask assembly and method having a fan and replaceable filter
US5318019A (en) * 1992-03-19 1994-06-07 Celaya Marty A Emergency portable oxygen supply unit
EP0736309A1 (de) * 1995-01-06 1996-10-09 Pai-Her Mou Lebensrettende Beatmungsvorrichtung
US8622057B2 (en) 2001-02-16 2014-01-07 Resmed Ltd Methods and apparatus for supplying clean breathable gas
WO2002066105A1 (en) * 2001-02-16 2002-08-29 Resmed Ltd. Methods and apparatus for supplying clean breathable gas
US7380551B2 (en) 2003-03-21 2008-06-03 Tvi Corporation Breathing apparatus
US7543584B2 (en) 2003-03-21 2009-06-09 Interspiro, Inc. Powered air purifying respirator system and breathing apparatus
EP2292291A3 (de) * 2003-08-15 2014-08-13 Shahar Hayek Beatmungsgerät
US10130831B2 (en) 2003-08-22 2018-11-20 Patriot Life Support, Inc. Self-contained breathing system
US7647927B2 (en) 2003-08-22 2010-01-19 Wilcox Industries Corp. Self-contained breathing system
US8113198B2 (en) 2003-08-22 2012-02-14 Wilcox Industries Corp. Self-contained breathing system
US8950401B2 (en) 2003-08-22 2015-02-10 Wilcox Industries Corp. Self-contained breathing system
WO2008068545A1 (en) * 2006-12-05 2008-06-12 Intertechnique A respiratory gas supply circuit to feed crew members and passengers of an aircraft with oxygen
WO2016157159A1 (en) * 2015-04-03 2016-10-06 Microsfere Pte. Ltd. Respiratory masks, systems and methods
CN107405508A (zh) * 2015-04-03 2017-11-28 米克罗斯菲尔有限公司 呼吸面罩、系统及方法
DE102016009486B4 (de) * 2015-09-03 2021-01-07 Dräger Safety AG & Co. KGaA Gebläsefiltersystem und Kopfstückmonitoreinheit in einem solchen Gebläsefiltersystem
US11291869B2 (en) 2017-11-15 2022-04-05 Immediate Response Technologies, Llc Modular powered air purifying respirator system
EP3915644A1 (de) * 2020-05-27 2021-12-01 Honeywell International Inc. Kompakte beatmungsanordnung
US20210369996A1 (en) * 2020-05-27 2021-12-02 Honeywell International Inc. Compact respirator assembly
US11998771B2 (en) * 2020-05-27 2024-06-04 Honeywell International Inc. Compact respirator assembly
CN112618984A (zh) * 2021-01-11 2021-04-09 淮南安裕机电科技有限责任公司 一种滤尘送风式防尘口罩

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