US 3366107 A
Description (OCR text may contain errors)
v R. L. FRANTOM APPARATUS FOR SUPPLYING BREATHABLE GAS FROM4 OXYGEN IN LIQUID FORM Filed June 18, 1964 Jan. 3o, 1968 TOR. lf3-Mr om M0( ATTORNEYS \\lOm United States Patent O Ohio Filed June 18, 1964, Ser. No. 376,032 4 Claims. (Cl. 12S-142.2)
This invention relates -to apparatus for supplying breathable gas from oxygen in liquid form, such as from a body of liquid air or liquid oxygen, to support life in a hostile atmosphere. The invention is particularly useful when embodied in a back or hand pack for use in zero gravity environment or situations requiring all position use.
The principal object of the present invention is to obtain optimum use of the exhaled gas in keeping the water and carbon dioxide content down to tolerable levels without the use of chemical absorbents, this being accomplished by freezing them out through heat exchange with the body of liquid air or liquid oxygen and by proportioning the flow of exhaled gas to the freezeout chamber to a flow directly back to the mask for reinhalation.
Another object is to maintain the recirculated gas at a suitable breathing temperature.
Another object is to provide such apparatus operating at a small positive pressure so as to eiiminate the need for both pressure reducers and also for heavy walled vessels.
Another object is to release oxygen or air from the liquid body only in gaseous form, a filter being provided for this purpose.
Another object is to provide such apparatus which will operate properly at zero gravity or in inverted positions, a special finned heat exchanger being provided through which the apparatus remains operative as long as the fins make some contact with the liquid air or oxygen or cold vapor thereof.
Another aim is not only to eliminate the need for chemical absorbents but also to provide apparatus which can be easily readied for reuse by urging or draining a freeze-out chamber.
Another object is to provide such apparatus which will be operative for a long period of duration due to the 860:1 ratio in expansion of oxygen from liquid to gas.
Another object is to minimize moving parts thereby to achieve a high level of reliability.
Other objects and advantages of the invention will be apparent from the following description and ydrawing which is a diagrammatic representation of apparatus for practicing the present invention.
The apparatus is desirably in the form of a hand held or back pack and includes a liquid air or oxygen storage container 1 which can be of conventional cylindrical form, with end heads 2 and 3 and surrounded by a jacketing she-ll 4, the space 5 between the container 1 and its jacketing shell 4 preferably containing a thermal insulation. The chamber within the container 1 in which the liquid air or oxygen is stored is designated at `6.
A feature of the invention comprises the employment of a shell '7 within the container 1 and forming a freezeout chamber 8. In order to render the apparatus operative at zero gravity or inverted positions, the shell 7 forming the freeze-out chamber 8 is provided with a plurality of external heat exchange tins 9 which radiate outwardly and reach to the internal surface of the container 1 and are arranged in spaced relation to each other and which are also provided at their peripheries with notches or openings 10 so that the liquid or boiled olf air or oxygen within the container 1 is free to circulate throughout this c011- tainer.
3,366,107 Patented Jan. 30, 1968 The container 1 can be filled with liquid air or oxygen by means of an inlet line 15 connecting with the end head 2 and having a lill valve 16. A line 18 connects with the other end head 3 and is provided with an absolute pressure regulator 19 which vents to the atmosphere in the event of an excess pressure developing within the container 1. This line 18 can also be provided with a manually operated vent valve 20.
The numeral 23 represents a face mask for the user of the apparatus and forming a breathing chamber 24. This breathing chamber connects with an exhale line or conduit 25 containing a check valve 26 which opens away from the breathing chamber 24. This exhale line or conduit connects with a proportioning valve 27 containing a valve member 28 which can be moved to discharge a regulated proportion of the exhalation gas into either a recirculation line or conduit 29 or a line or conduit 30. The recirculation line 29 connects with an inhalation line 32 communicating with the breathing chamber 24 of the mask 23 and containing a checkv valve 33, between the line or conduit 29 and mask 23, which opens toward the mask 23.
The line or conduit 30 extends through the end head 2 of the container 1 for the liquid air or oxygen and is connected to the shell 7 forming the freeze-out chamber 8 so that the part of the gas as exhaled by the user delivered by the proportioning valve 27 into the line 30 e11- ters this freeze-out chamber 8. On contacting the walls of this chamber the water vapor and carbon dioxide freeze out of the gas due to heat exchange with the surrounding liquid air or oxygen in the chamber 6 within the container 1. Purged of its water vapor and carbon dioxide, the exhaled gas passes into the inhale line or conduit 32 for rebreathing, this purged gas joining the Warm recirculated exhaled gas being delivered from the recirculation line or conduit 29 to the inhale line or conduit 32.
The liquid air or oxygen in the chamber 6 within the container 1 is used to support the users life in a hostile atmosphere. Boil-off of liquid oxygen or air for this purpose is obtained from heat driven from the exhalation delivered to the freeze-out chamber 3. It is desirable that no liquid escape from the liquid air or oxygen chamber 6 and to this end an outlet filter 35 is provided at each end head 2, 3 these lters allowing the passage of gas but being made of porous bronze or the like so that the surface tension of the liquid prevents the escape of liquid therethrough. The lines 36 from these filters 35 serve a common line 38 delivering the boiled off gas or liquid oxygen to the recirculation line or conduit 29.
In the use of the apparatus the valve member 28 0f proportioning valve 27 is set so as to deliver the optimum proportion of exhalation from the breathing chamber 24 to the lines 29 and 30. This gas is supplied by the eX- halation Iof the user into the breathing chamber 24 through the exhale line or conduit 25 past the check valve 26. The proportion of the exhalation delivered into the re circulation line or conduit 29 returns to the inhale line or conduit 32 for the mask 23 and passes the check valve 33 into the breathing chamber 24 when the user inhales. The portion of exhalation delivered to the line 30 is conducted to the freeze-out chamber 8. In this freeze-out chamber the water vapor and carbon dioxide are frozen out in heat exchange with the liquid air or oxygen contained within the chamber 6 of the container 1. By this means the concentration of the Water vapor and carbon dioxide is kept down at tolerable levels, the gas escaping from the freeze-out chamber 8 through the inhale line or conduit 32 to the mask 23. On mixing with the exhalation returning directly through the line 29 this cold gas is heated to a usable level.
Through this heat exchange and freeze-out within the freeze-out chamber 8, a part of the liquid air cr oxygen contained within the chamber 6 ofthe container 1 is boiled olf and escapes, in gaseous form, through the lters 35.-
These filters are of such design as to prevent the escape of liquid, the surface tension of the liquid preventing its passage through these filters. From these filters the boiled off gas or air is delivered through the lines 36 and 38 to the recirculation line or conduit 29 and thence through the inhale line or lconduit 32 to the breathing chamber 24 of the mask.
It will particularly be noted that the above freeze-out and boil-off in the chambers 8 and 6, respectively, will obtain as long as the ns 9 make some Contact with cold liquid or vapor within the chamber 6 of the container 1 for the liquid air or oxygen. Accordingly the apparatus is operative under zero gravity or inverted conditions and also is operative beyond the duration of boil-olf of the full contents of liquid air or oxygen from the chamber 6, such duration being extremely long in comparison to weight of the apparatus due to the 860:1 expansion of oxygen from liquid to gas.
It will also be noted that the proportioning valve 27 can be adjusted to allow sufficient exhalation to pass through the freeze-out chamber S to accomplish (a) freeze-'out of water and carbon dioxide sufliciently to keep their concentration in the recirculated gas down to tolerable levels, (b) 'boil-off of sufficient liquid air or oxygen to make up for the consumed oxygen and (c) maintaining the inhaled gas at a suitable breathing temperature.
From the foregoing it will be seen that this present invention accomplishes the objects set forth in a very light weight and reliable apparatus.
1. Apparatus for supplying breathable gas from oxygen in liquid form, which comprises a container for said oxygen in liquid form having an outlet therefor, a shell within said container and surrounded by said oxygen in liquid form to provide a freeze-out chamber, an inlet to said freeze-out chamber extending through the wall of said container, an outlet from said freeze-out chamber extending through the wall of said container, a face mask having a breathing chamber, an exhale conduit connecting said breathing chamber directly with said inlet to said freeze-out chamber to deliver exhaled gas containing carbon dioxide and Water evolved from the users respiration to said freeze-out chamber to freeze out both such carbon dioxide and water so delivered thereto, a check valve in said exhale conduit and opening toward said freeze-out chamber, an inhale conduit connecting said outlet from said freeze-out chamber with said breathing chamber, a check valve in said inhale conduit and opening toward said breathing chamber, a recirculation conduit connecting said exhale conduit with said inhale conduit between its check valve and said freeze-out chamber and another conduit providing communication for said outlet from said container Iwith said inhale conduit between its check valve and said freeze-out chamber.
2. Apparatus as set forth in claim 1 wherein a proportioning valve is included in the connection between said exhale conduit and said recirculation conduit to regulate the proportion of gas exhaled by the user which is delivered to the freeze-out chamber and to the lrecirculation conduit.
3. Apparatus as set forth in claim 1 wherein a filter is arranged across said outlet of said container to permit the ow of gas and to bar the flow of liquid.
4. Apparatus as set forth in claim 1 additionally including heat transfer fins on the exterior of said shell reaching to the adjacent internal surfaces of said container and serving to render said freeze-out chamber operative as long as cold liquid or gas exists in said container in contact with said fins.
References Cited UNITED STATES PATENTS 3,068,658 l2/l962 Weber 62-50 FOREIGN PATENTS 1,268,044 6/1961 France.
816,874 7/l959 Great Britain.
RICHARD A. GAUDET, Prima/'y Examiner.
W. E, KAMM, Examiner.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,366 ,107 January 30 1968 Richard Louis Frantom It is certified that error appears n the above identified patent and that said Letters Patent are hereby corrected as shovm below:
Column l, line 4l, for "urging" read purging Signed and sealed this 24th day of June 1969.
Edward M. Fletcher, J r.
Commissioner of Patents Attesting Officer WILLIAM E. SCHUYLER, JR.