EP0202721A1 - Schaltventil - Google Patents

Schaltventil Download PDF

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Publication number
EP0202721A1
EP0202721A1 EP86200897A EP86200897A EP0202721A1 EP 0202721 A1 EP0202721 A1 EP 0202721A1 EP 86200897 A EP86200897 A EP 86200897A EP 86200897 A EP86200897 A EP 86200897A EP 0202721 A1 EP0202721 A1 EP 0202721A1
Authority
EP
European Patent Office
Prior art keywords
piston
source
main
pressure
auxiliary
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Withdrawn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
EP86200897A
Other languages
English (en)
French (fr)
Inventor
Johannes Petrus Maria Laarhoven
Jacobus Bareman
Marinus Korstanje
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.)
Dow Chemical Nederland BV
Original Assignee
Dow Chemical Nederland BV
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 Dow Chemical Nederland BV filed Critical Dow Chemical Nederland BV
Publication of EP0202721A1 publication Critical patent/EP0202721A1/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Withdrawn legal-status Critical Current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
    • A62B9/00—Component parts for respiratory or breathing apparatus
    • A62B9/02—Valves

Definitions

  • the invention relates to a switch valve, in particular to a multiway valve for connecting an apparatus to different fluid supplies.
  • auxiliary source such as an auxiliary supply carried in a tank by the user of a breathing apparatus.
  • immediate switch to the auxiliary supply is necessary.
  • a known automatically switching valve which functions this way is provided in the housing thereof with check valves in the respective connecting passages between the air inlet connections and the outlet connection to the breathing apparatus and as soon as the pressure in the main-source supply line drops below the pressure in the auxiliary-source supply line the valve in the auxiliary-source supply line opens and the valve in the main-source supply line closes.
  • a problem with this known switch valve is that depending on the type, portable compressed air tanks used in practice are adjusted to different working pressures which may vary from 5-8 bar and it is therefore possible that the main-source pressure, at least the pressure of the air supplied from the source, is too low in relation to the auxiliary supply pressure, so that from the start, only air from the auxiliary tank is supplied to the breathing apparatus.
  • the main-source pressure at least the pressure of the air supplied from the source
  • the auxiliary supply pressure so that from the start, only air from the auxiliary tank is supplied to the breathing apparatus.
  • the object of the invention is an automatically switching valve whereby this disadvantage is obviated.
  • a switch valve comprising a housing having connection means for a main-source supply-line, for an auxiliary-source supply-line, and for a delivery line to a breathing apparatus as well as pressure responsive control means in connecting passages extending between the respective supply line connections with the delivery line connection
  • said control means comprise a differential piston the smaller part of which is loadable by the auxiliary-source pressure and the larger part by the main-source pressure, and which piston in each of its end positions closes off one of the said connecting passages and clears the other passage.
  • a relatively low main-source presure is sufficient to accomplish a piston displacement in the sense of interrupting the supply from the reserve tank. It is . for example possible to select the ratio of the piston diameters such that even a nine times higher auxiliary-source pressure than the main-source supply pressure acting on the larger piston end face will move the piston to the end position closing off the auxiliary-source supply line, so that it is guaranteed that irrespective of the adjusted working pressure of the reserve tank, the reserve supply is only tapped when the main-source pressure falls off entirely or substantially entirely.
  • a venting bore can be provided in the end wall concerned, through which a rod connected to the piston extends so as to leave an annular passage, said rod carrying a valve which in the end position of the piston which is determined by the main-source pressure closes off said annular passage.
  • a switch valve of the subject kind comprising a piston for selectively closing off mains air supply passages and emergency air supply passages towards a delivery line is known per se from GB-A-2,058,580.
  • This known valve must be manually reset to switch back to the main supply after the auxiliary supply has been activated. The switching is not automatically back and forth between the auxiliary and main sources and the piston is neither of the differential type nor loadable by the main source pressure.
  • US-A-4,499,914 discloses the use of a differential piston in a shuttle valve which is part of a complicated selector valve device for use in an aircraft on board oxygen generation system with high pressure oxygen backup, for blending several gaseous components to provide an optimized breathable air supply.
  • the switching of the shuttle valve is not directly controlled by the presence of suffiecient mains air pressure, but by pressure supplied to the shuttle valve by the main blending valve.
  • this known valve differs from the valve according to the subject invention in that the larger end of the differential piston is not exposed to the mains air pressure and the known piston is not directly loadable by the auxiliary pressure either, but by a spring.
  • the switch valve comprises a housing 1 with a connection 2 for a reserve tank, a connection 3 for a remote main source, and a connection 4 for a breathing apparatus comprising a breathing mask.
  • a differential piston 5 is displaceable between end positions depicted in Fig. 1 and Fig. 2.
  • the differential piston 5 has a larger cylinder part 6 and a smaller cylinder part 7 and is movable within fitting cylinder spaces 8 and 9 respectively.
  • the cylinder space 8 is positioned in the connecting path 10 between the main-source connection 3 and the outlet connection 4 to the breathing mask and the cylinder space 9 is situated in the connecting path 11 between reserve tank connection 2 and mask connection 4.
  • a venting bore 13 is provided in the end wall 12 of the cylinder space 8 .
  • a 'rod 14 extends through bore 13 leaving an annular channel 15.
  • Rod 14 carries a valve 16 for closing annular channel 15 on the outside.
  • Valve 16 may be arranged within an enclosure 17.
  • a venting bore 18 for cylinder space 8 is provided on the other side of the larger piston part 6.
  • the switch from the situation depicted in Fig. 1 to the situation according to Fig. 2 takes place when the main-source pressure Ps becomes so low that breathing becomes difficult. Depending on the specific apparatus and the adjustment thereof, this pressure will, in general, vary from at least 0.5 to 1 bar above atmosphere pressure. At such low source pressures, the piston 5 moves downwards, thereby allowing air and/or oxygen from the auxiliary tank to flow through connection 2 to the mask connection 4. Once the source pressure Ps increases again to a given minimum pressure, the piston will again move upwards, and operation of the device will return to the mode depicted in Fig. 1 wherein air and/or oxygen is fed from the source to the breathing apparatus.
  • the pressure required to move the piston upwards be somewhat different from that at which the piston will fall downwards.
  • the pressure required to move the piston from its down position upwards to its up position is 2.5 bars above atmospheric pressure. This difference in source pressures is created by the provision of bore 13.
  • bore 13 is open and air and/or oxygen flowing through connection 3 is able to escape through the restricted opening 13 and through enclosure 17.
  • the bore 13 is closed and all the air and/or oxygen flowing through connection 3 acts on the bottom surface of the larger piston part 6.

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)
EP86200897A 1985-05-23 1986-05-22 Schaltventil Withdrawn EP0202721A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL8501474A NL8501474A (nl) 1985-05-23 1985-05-23 Omschakelklep.
NL8501474 1985-05-23

Publications (1)

Publication Number Publication Date
EP0202721A1 true EP0202721A1 (de) 1986-11-26

Family

ID=19846027

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86200897A Withdrawn EP0202721A1 (de) 1985-05-23 1986-05-22 Schaltventil

Country Status (2)

Country Link
EP (1) EP0202721A1 (de)
NL (1) NL8501474A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150367150A1 (en) * 2013-02-08 2015-12-24 Honeywell International Inc. Automatic Switching Device for a Breathing Apparatus with an Alarm-Relief Function and Automatic Reset

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3618636A (en) * 1969-03-26 1971-11-09 Dynamco Inc Pneumatic logic valve
FR2232715A1 (de) * 1973-06-08 1975-01-03 Zahnradfabrik Friedrichshafen
US4499914A (en) * 1983-04-14 1985-02-19 Litton Systems, Inc. Selector valve for an aircraft on board oxygen generation system with high pressure oxygen backup

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3618636A (en) * 1969-03-26 1971-11-09 Dynamco Inc Pneumatic logic valve
FR2232715A1 (de) * 1973-06-08 1975-01-03 Zahnradfabrik Friedrichshafen
US4499914A (en) * 1983-04-14 1985-02-19 Litton Systems, Inc. Selector valve for an aircraft on board oxygen generation system with high pressure oxygen backup

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150367150A1 (en) * 2013-02-08 2015-12-24 Honeywell International Inc. Automatic Switching Device for a Breathing Apparatus with an Alarm-Relief Function and Automatic Reset
US10086219B2 (en) * 2013-02-08 2018-10-02 Honeywell International Inc. Automatic switching device for a breathing apparatus with an alarm-relief function and automatic reset

Also Published As

Publication number Publication date
NL8501474A (nl) 1986-12-16

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19870527

RIN1 Information on inventor provided before grant (corrected)

Inventor name: KORSTANJE, MARINUS

Inventor name: LAARHOVEN, JOHANNES PETRUS MARIA

Inventor name: BAREMAN, JACOBUS