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EP0602847A1 - Indicateur d'écoulement - Google Patents

Indicateur d'écoulement Download PDF

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Publication number
EP0602847A1
EP0602847A1 EP93309652A EP93309652A EP0602847A1 EP 0602847 A1 EP0602847 A1 EP 0602847A1 EP 93309652 A EP93309652 A EP 93309652A EP 93309652 A EP93309652 A EP 93309652A EP 0602847 A1 EP0602847 A1 EP 0602847A1
Authority
EP
European Patent Office
Prior art keywords
air
orifice
float
tube
flow
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Withdrawn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
EP93309652A
Other languages
German (de)
English (en)
Inventor
Colin Arthur C/O Middlemace Limited Church
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.)
MIDDLEMACE Ltd
Original Assignee
MIDDLEMACE 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 MIDDLEMACE Ltd filed Critical MIDDLEMACE Ltd
Publication of EP0602847A1 publication Critical patent/EP0602847A1/fr
Withdrawn legal-status Critical Current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
    • A62B18/08—Component parts for gas-masks or gas-helmets, e.g. windows, straps, speech transmitters, signal-devices
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
    • A62B9/00—Component parts for respiratory or breathing apparatus
    • A62B9/006—Indicators or warning devices, e.g. of low pressure, contamination

Definitions

  • This invention relates to flow indicators. More particularly, the invention relates to a flow indicator for monitoring the flow of air or breathable gas supplied from an external supply to the breathing zone of a respirator.
  • the invention is concerned with respirators of the kind which are worn by personnel working in hazardous environments and which are provided with an external source of air or breathable gas.
  • the respirators which may be in the form of a hood or helmet, provide a breathing zone surrounding the wearer's mouth and nostrils.
  • the flow of air or breathable gas to the breathing zone must be maintained at a level sufficient for respiration and also to ensure that, for example, gases or dust from the outside atmosphere are prevented from entering the breathing zone. It is therefore desirable to provide an indicator which monitors the rate of flow of air or breathable gas to the respirator and gives an immediate indication to the wearer if the rate of flow falls below a predetermined level.
  • This invention consists of a low flow indicator for monitoring the flow of air or breathable gas supplied from an external supply to the breathing zone of a respirator, comprising an orifice member having an orifice through which part or all of the air or gas flows before reaching the breathing zone, a pressure sensing device connected to the member so as to respond to the pressure differential created across the orifice by the flow of air or gas, and means for alerting the wearer of the respirator when the pressure sensing device senses that the pressure differential falls below a predetermined value.
  • the pressure sensing device comprises a vertical tube positioned in the breathing zone, the tube being open at its upper end and connected at its lower end to the said member so that the pressure differential generated across the said orifice causes flow of air or gas through the tube, and a float housed within the tube and normally resting on a support within the tube, the float being arranged so that the flow of air through the tube when the pressure differential is above the predetermined value lifts the float from the support.
  • the indicator may be positioned in the field of vision of the wearer, so that the position of the float will give a visual indication to the wearer if the pressure differential falls below the predetermined value.
  • the float may be arranged to operate an electrical switch, connected to a circuit operable to give a visual or audible signal if the pressure differential falls below the predetermined value.
  • the cross-sectional area of the orifice is adjustable, to allow the device to be calibrated.
  • a respirator helmet comprises a helmet shell adapted to fit over the crown of the head of the wearer and having a rearwardly extending portion 12.
  • a visor 14 extends downwards from the front of the helmet shell 10, to define a breathing zone 30 around the face of the wearer.
  • a skirt 16 of flexible material is connected to the helmet shell and visor and fits closely around the neck of the user, the lower rim of the skirt being provided with a drawstring 17.
  • the rear portion 12 of the helmet shell 10 has an inlet 18 which, in use, is connected through a flexible hose 20 to a source of air or breathable gas, such as a compressed air bottle or a compressor, through a suitable pressure regulator.
  • the helmet shell 10 is supported on the wearer's head by a suitable harness or cradle and is shaped to provide a passage over the crown of the wearer's head to the breathing zone 30, so that air supplied to the inlet 18 flows to the breathing zone.
  • the air or gas exits from the breathing space through vents 24 in the lower part of the visor 14.
  • the respirator is provided with a low flow indicator, comprising a member 40 providing a restrictive orifice through which air is supplied to the interior of the helmet, and a pressure sensor 50 connected to the member 40 through a flexible tube 48.
  • the member 40 consists of a short cylinder 42, connected at its lower end to the inlet 18 and having at its upper end an orifice 44 through which the air flows into the interior of the helmet shell.
  • the orifice 44 has an area less than the cross-sectional area of the cylinder 42, so that the flow of air through the orifice creates a pressure differential across the orifice.
  • the flexible tube 48 is connected at one end to a branch opening into the side wall of the cylinder 42 through a small aperture 49.
  • the pressure sensor 50 consists of a cylinder 52 mounted in the breathing zone 30 of the helmet.
  • the cylinder 52 is connected at its lower end to the flexible tube 48, and is open at its upper end.
  • the tube contains a spherical float 54, of diameter slightly less than the inside diameter of the cylinder 52, so that the float 54 can move freely in the cylinder.
  • the lower and upper limits of movement of the float are defined by pins 56 and 58 near the lower end and upper end of the cylinder.
  • the pressure differential across the orifice 44 generated by air flow through the member 40 produces an increased pressure inside the member 40.
  • Part of the airflow is diverted to the pressure sensor 50 through the flexible tube 48, which transmits the increased pressure in member 40 to the lower end of the cylinder 52.
  • the airflow through the cylinder 52 if it is above a predetermined value, lifts the float 54 off the lower pin 56 and holds it in contact with the upper pin 58. The position of the float therefore gives an indication as to whether the rate of flow of air into the interior of the helmet is above or below a predetermined value.
  • the predetermined value is set by the cross-sectional area of the orifice 44.
  • the orifice may be made adjustable, so that the flow indicator can be calibrated before it is fitted to the helmet.
  • the pressure sensor 50 may be mounted in the helmet so that it is within the view of the wearer of the helmet, so that the movement of the float 54 from its upper position will give a visual indication that the rate of flow of air has fallen below the predetermined value.
  • the pressure sensor may be arranged to operate an electrical circuit to provide an audible or visual warning.
  • the float 54 may be made of, or coated with, an electrically conductive material, and the upper pin 58 may be provided as two half-pins the ends of which are separated by a gap which is bridged by the float 54 when it is in its uppermost position.
  • the half-pins form electrical terminals which are connected to an electrical circuit 60 which operates an audible warning device 62.
  • the circuit 60 is arranged so that the warning device 62 is disabled as long as the circuit including the half-pins 58 is closed by contact with the float 54, and is energised to provide an audible warning if the float 54 moves away from the half-pins.
  • the flow indicator of the present invention has the advantage that its operation is independent of the pressure inside the helmet, and depends only on the rate of flow of air or breathable gas supplied to the helmet.
  • the flow indicator can therefore be calibrated and tested before being fitted to the helmet.

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)
  • Measuring Volume Flow (AREA)
EP93309652A 1992-12-14 1993-12-02 Indicateur d'écoulement Withdrawn EP0602847A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9226054 1992-12-14
GB929226054A GB9226054D0 (en) 1992-12-14 1992-12-14 Flow indicator

Publications (1)

Publication Number Publication Date
EP0602847A1 true EP0602847A1 (fr) 1994-06-22

Family

ID=10726591

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93309652A Withdrawn EP0602847A1 (fr) 1992-12-14 1993-12-02 Indicateur d'écoulement

Country Status (3)

Country Link
EP (1) EP0602847A1 (fr)
AU (1) AU5223393A (fr)
GB (1) GB9226054D0 (fr)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2339392A (en) * 1998-07-10 2000-01-26 Respitec Company Limited Breathing mask
EP1038553A3 (fr) * 1999-03-19 2000-10-04 3M Innovative Properties Company Indicateur de débit pour appareils respiratoires
WO2001097914A1 (fr) 2000-06-16 2001-12-27 3M Innovative Properties Company Regulateur de pression pour systeme respiratoire
WO2004084665A2 (fr) 2003-03-27 2004-10-07 Helmet Integrated Systems Limited Respirateur
WO2006110084A1 (fr) * 2005-04-12 2006-10-19 Marek Blasiak Unite indicatrice
JP2010522043A (ja) * 2007-03-23 2010-07-01 スリーエム イノベイティブ プロパティズ カンパニー 呼吸装置フード用の空気送達装置
US9868001B2 (en) 2007-10-05 2018-01-16 3M Innovative Properties Company Respirator flow control apparatus and method
US10137320B2 (en) 2007-03-23 2018-11-27 3M Innovative Properties Company Respirator flow control apparatus and method
US10391337B2 (en) 2007-11-12 2019-08-27 3M Innovative Properties Company Respirator assembly with air flow direction control
WO2021151042A1 (fr) 2020-01-23 2021-07-29 Rpb Safety, Llc Respirateur à air fourni

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE511288C2 (sv) * 1995-07-05 1999-09-06 Comasec International Sa Andningsutrustning som vid fraånfall automatiskt öppnar mot ytterluften
CN110917517A (zh) * 2018-09-19 2020-03-27 长沙环康科技有限公司 一种多功能过滤式全脸防毒面罩

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR594676A (fr) * 1925-03-07 1925-09-17 Aera Sa Des Ets Dispositif pour mesurer quantitativement tous débits gazeux, applicable, en particulier, aux appareils distributeurs d'oxygène
GB2130893A (en) * 1982-11-26 1984-06-13 Barrie Bancroft Performance monitor for respirator helmets
GB2225958A (en) * 1988-12-19 1990-06-20 Sentry Safety Limited Breathing apparatus warning device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR594676A (fr) * 1925-03-07 1925-09-17 Aera Sa Des Ets Dispositif pour mesurer quantitativement tous débits gazeux, applicable, en particulier, aux appareils distributeurs d'oxygène
GB2130893A (en) * 1982-11-26 1984-06-13 Barrie Bancroft Performance monitor for respirator helmets
GB2225958A (en) * 1988-12-19 1990-06-20 Sentry Safety Limited Breathing apparatus warning device

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2339392B (en) * 1998-07-10 2002-10-02 Respitec Company Ltd Indicators for breathing masks
GB2339392A (en) * 1998-07-10 2000-01-26 Respitec Company Limited Breathing mask
EP1038553A3 (fr) * 1999-03-19 2000-10-04 3M Innovative Properties Company Indicateur de débit pour appareils respiratoires
US6615828B1 (en) 1999-03-19 2003-09-09 3M Innovative Properties Company Flow indicator device for respirators
WO2001097914A1 (fr) 2000-06-16 2001-12-27 3M Innovative Properties Company Regulateur de pression pour systeme respiratoire
US7810492B2 (en) 2003-03-27 2010-10-12 Helmet Integrated Systems Limited Respirator
WO2004084665A2 (fr) 2003-03-27 2004-10-07 Helmet Integrated Systems Limited Respirateur
AU2004224544B2 (en) * 2003-03-27 2009-07-16 Helmet Integrated Systems Limited Respirator
WO2006110084A1 (fr) * 2005-04-12 2006-10-19 Marek Blasiak Unite indicatrice
JP2010522043A (ja) * 2007-03-23 2010-07-01 スリーエム イノベイティブ プロパティズ カンパニー 呼吸装置フード用の空気送達装置
US8936022B2 (en) 2007-03-23 2015-01-20 3M Innovative Properties Company Air delivery apparatus for respirator hood
US10137320B2 (en) 2007-03-23 2018-11-27 3M Innovative Properties Company Respirator flow control apparatus and method
US11130008B2 (en) 2007-03-23 2021-09-28 3M Innovative Properties Company Respirator flow control apparatus and method
US12329994B2 (en) 2007-03-23 2025-06-17 3M Innovative Properties Company Respirator flow control apparatus and method
US9868001B2 (en) 2007-10-05 2018-01-16 3M Innovative Properties Company Respirator flow control apparatus and method
US10391337B2 (en) 2007-11-12 2019-08-27 3M Innovative Properties Company Respirator assembly with air flow direction control
WO2021151042A1 (fr) 2020-01-23 2021-07-29 Rpb Safety, Llc Respirateur à air fourni

Also Published As

Publication number Publication date
AU5223393A (en) 1994-06-23
GB9226054D0 (en) 1993-02-10

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