MINE RESCUE BREATHING APPARATUS

• US 3,805,780 A
• Filed: 06/09/1972
• Issued: 04/23/1974
• Est. Priority Date: 06/09/1972
• Status: Expired due to Term

• Current Assignee: Environmental Technologies Group, Inc.
• Original Assignee: John W. Henneman, Robert L. Cramer
• Inventors: Cramer, Robert L., Henneman, John W.
• Primary Examiner(s): Gaudet, Richard A.
• Assistant Examiner(s): Recla, Henry J.
• Application Number:
  US05/261,208
• Time in Patent Office: 683 Days
• Field of Search: 128/142.2,142.3,145,145.6,145.8,140,185,191,196,197,202,203,204,209,211,142 137/63R,568 417/402,401,395 91/417,47
• US Class Current: 128/202.22
• CPC Class Codes: A62B 7/04 and lung-controlled oxygen or air valves
• CPC Class Codes: Y10S 137/908 Respirator control
• CPC Class Codes: Y10T 137/86043 Reserve or surge receiver

Abstract

A closed loop breathing system having a circulation pump for supplying a recipient with an oxygen enriched breathable fluid in response to an inhalation demand sensed by a regulator. The inhalation demand as sensed by the regulator opens a servo valve allowing oxygen to flow through an injection nozzle into a mixing chamber. The flow of oxygen creates a pressure differential across a wall. The pressure differential moves the wall to collapse a bellows thereby forcing breathed air into the mixing chamber to form a breathable fluid under a predetermined pressure. This breathable fluid passes through a filter to remove odors and a heat exchanger to maintain the temperature within a predetermined range before being delivered to the recipient.

Claims

1. In a closed loop breathing system, pumping means for delivering a breathable fluid enriched with oxygen to a recipient in response to an operational signal actuating a regulator means, said pumping means comprising:

a housing having a cavity therein;

wall means for dividing said cavity into a power chamber and a control chamber, said control chamber having a first inlet port connected through an operational conduit to a source of oxygen under pressure and a first outlet port connected to a nozzle means in said regulator means, said power chamber having a second inlet port connected through said operational conduit to the source of oxygen under pressure, said first inlet port having a smaller opening than said second inlet port to proportionally restrict the flow of oxygen into said control chamber;

resilient means located in said control chamber for urging said wall means toward said power chamber;

variable volume reservoir means connected to said wall means having a return port connected to a return conduit coming from said recipient for retaining breathed fluid and a supply port connected to a mixing chamber, nozzle means connected to said regulator means for injecting oxygen into said mixing chamber;

a supply conduit connected to said mixing chamber for communicating said breathable fluid to the recipient;

means for sensing an inhalation demand by the recipient to devElop said operational signal, and actuating said regulating means; and

operational control means connected to said operational conduit for permitting oxygen under pressure to be continually present at the first inlet port of said control chamber and the second inlet port of said power chamber to provide a balanced pressure across said wall means, said regulator means upon receiving said operational control signal allowing oxygen to flow from said control chamber through said nozzle means into said mixing chamber, said oxygen flowing from said control chamber creating a pressure differential acrosss said wall means which overcomes said resilient means and moves the wall means toward said control chamber, said wall means upon moving causing a portion of the breathed fluid in the variable volume reservoir means to flow through the supply port into the mixing chamber, said breathed fluid and oxygen injected into said mixing chamber forming said breathable fluid at a pressure sufficient to alleviate said inhalation demand to thereby permit said regulator means to terminate said oxygen flow through said nozzle means, said oxygen flow termination allowing the oxygen under pressure to flow through the first inlet port to eliminate said pressure differential, said resilient means with the elimination of said pressure differential moving said wall means toward said power chamber causing said variable volume reservoir means to draw therein through said return port from the return conduit a quantity of breathed fluid sufficient to that expelled through said supply port to the mixing chamber.

2. The closed loop breathing system, as recited in claim 1, wherein said variable volume reservoir means includes:

piston means having a shaft which extends through said housing into the control chamber, said shaft being attached to said wall means;

a stationary end plate wherein said return port and supply port are located; and

expandable bellows means connected to said piston means and attached to said end plate, said wall means upon moving transmitting a driving force on said piston means through the shaft causing said bellows means to be compressed and force breathed fluid into the mixing chamber.

3. The closed loop breathing system, as recited in claim 2, which further includes:

filter means located in said supply conduit downstream from said mixing chamber for removing CO2 and odors from the breathable fluid to insure freshness.

4. The closed loop breathing system, as recited in claim 3, which further includes;

heat exchanger means located in said supply conduit downstream from said filter means to maintain the temperature of said breathable fluid within a predetermined range.

5. The closed loop breathing system, as recited in claim 4, which further includes:

relief means located in said supply conduit downstream from said heat exchanger means for limiting the operating pressure of said breathable fluid.

6. The closed loop breathing system, as recited in claim 5, wherein said regulator means includes:

emergency flow means connected to said source of oxygen and the supply conduit downstream from said heat exchanger for adding additional oxygen to the breathable fluid when said inhalation demand exceeds a predetermined limit.

7. The closed loop breathing system, as recited in claim 6, which further includes:

pressure reducer means located in said operational conduit for maintaining the oxygen in the power chamber and control chamber at a relatively constant pressure.

8. The closed loop breathing system, as recited in claim 7, which further includes:

fluid pressure warning means connected to said operational conduit for giving a continuous audible signal when the pressure of the source of oxygen reaches a predetermined level.

9. The closed loop breathing system, as recited in claim 8, wherein said fluid pressure warning means includes:

a stepped bore within said housing terminating adjacent a storage chamBer, said storage chamber being connected to said operational conduit, said storage chamber having an opening into said stepped bore;

poppet valve means resiliently positioned against said opening for retaining oxygen under pressure in said storage chamber;

driver means loosely positioned in a first portion of the stepped bore adjacent said storage chamber, said first portion being in communication with the atmosphere through a slot adjacent a first shoulder which separates the first portion from a second portion of the stepped bore;

plunger means having a first end section connected to said driver means, said first end section and a second end section with a small diameter separated from a large diameter section, said first end section being sealed in said second portion of said stepped bore and said large diameter portion being sealed in a third portion of said stepped bore to form a pressure indicator chamber therein;

said pressure indicator chamber being connected to the oxygen under pressure in the operational conduit;

resilient means surrounding said second end of the plunger means and located in a fourth portion of the stepped bore for urging said driver means toward said storage chamber; and

bell means adjacent said second end, said oxygen under pressure acting on said large diameter section to overcome said resilient means and drive the second end of the plunger against said bell means causing a sound to be created, said resilient means upon the pressure of the oxygen in the indicator chamber reaching a predetermined level urging the plunger means away from the bell means causing the driver means to unseat the poppet valve means allowing oxygen under pressure into the first portion of the stepped bore moving the driver means away from the valve means, said driver means acting on the first end of the plunger to aid the oxygen pressure force acting on the large diameter portion to strike the second end against the bell means, said oxygen under pressure in the first portion of the stepped bore escaping through said slot upon the second end contacting the bell means permitting the resilient means to repeatedly move the driver means into contact with the valve means and provide a continuous signal.

10. The closed loop breathing system, as recited in claim 8, wherein said operational control means includes:

a first chamber adjacent opening from the source of oxygen under pressure, said first chamber being connected to said operational conduit;

a second chamber adjacent the first chamber, said second chamber being connected on a purge conduit to the return port of the variable volume reservoir means, said first and second chambers being connected by a passageway;

adjustable seat means located in said second chamber and in communication with said purge conduit;

stem means having a first face on one end adjacent the one end opening to the source of oxygen, a second face adjacent the passageway and a third face adjacent the adjustable seat means;

resilient means for urging the stem means toward the second chamber; and

positioning means connected to said adjustable seat for moving the first face of the stem means against the housing surrounding the opening in the first chamber from the source of oxygen to prevent the flow of oxygen under pressure into the first chamber in a first mode, said resilient means urging the third face against the adjacent seat in a second mode of the positioning means allowing oxygen under pressure to pass through the opening in the first chamber into the operational conduit and second chamber, said resilient means urging the second face against the passageway in a third mode of the positioning means allowing the oxygen under pressure to flow through the purge conduit to initially charge the breathed fluid in the variable volume chamber with oxygen.