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Closed cycle respirator with emergency oxygen supply

  • US 4,423,723 A
  • Filed: 03/11/1982
  • Issued: 01/03/1984
  • Est. Priority Date: 03/13/1981
  • Status: Expired due to Fees
First Claim
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1. A closed cycle respirator with emergency oxygen supply comprising:

  • a breathing air circuit;

    a breathing bag connected in said circuit;

    a carbon dioxide absorber connected in said circuit;

    a pressurized oxygen supply container having an outlet;

    a pressure reducer connected to said outlet;

    an oxygen supply line having one end connected to said pressure reducer;

    a switching valve connected to the opposite end of said oxygen supply line and having a first position and a second position;

    a first oxygen flow path connected from said switching valve to said bag and communicating with said oxygen supply line when said switching valve is in said first position;

    a second oxygen flow path connected from said switching valve to said bag and communicating with said oxygen supply line when said switching valve is in said second position;

    a solenoid valve connected in said first flow path;

    a first control element connected to said solenoid valve for opening said solenoid valve;

    a first oxygen sensor for sensing oxygen in said bag connected to said first control element for activating said first control element to open said solenoid valve when less than a selected amount of oxygen is sensed in said bag;

    a second control element connected to said switching valve for switching said switching valve between its first and second position;

    a second oxygen sensor in said breathing bag connected to said second control element for switching said switching valve from its first to its second position when a level of oxygen is sensed in said bag to be above a selected upper limit or below a selected lower limit;

    proportioning means in said second flow path for regulating a flow of oxygen into said bag from said oxygen supply line with said switching valve in its second position; and

    a switching line having one end connected to said second flow path and automatically operable regulator means connecting the opposite end of said switching line to said breathing air circuit for supplying oxygen to said breathing air circuit from said oxygen supply line when said switching valve is in its second position and in response to decreased pressure in said breathing air circuit.

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