US3441041A - Air injector for breathing apparatus - Google Patents

Description

AIR INJECTOR FOR BREATHING APPARATUS Filed Nov. 21, 1966 INVENTOR Peter Schrez'ber' ATTORNEYS United States Patent Int. Cl. G05d 1] 00; E03b U.S. Cl. 137-98 6 Claims ABSTRACT OF THE DISCLOSURE In a breathing apparatus, an atmospheric air injector is coupled with a nutrient gas injector for selectively supplying atmospheric air to the breathing system.

A breathing apparatus is known which, among other things, is provided with one or more injectors which are used to create less than and greater than atmospheric pressure in the brathing apparatus and in the lungs of a patient. Such apparatus has been provided with an opening for the purpose of drawing in fresh atmospheric air in order to save on compressed gas.

Such a breathing apparatus can both supply gas to the lungs of patients who are not able to breath on their own or to withdraw gas from the lungs. Valves controllable in diiferent ways are used for the supply of gas. An injector is used to withdraw gas from the lungs and to supply the gas needed for breathing. The injector is connected to a compressed gas supply.

Depending upon the size of the lungs, the amount of gas needed is metered by means of a nozzle for changing the pressure in front of the nozzle. The injector nozzle can be used as the throttle. In order to save gas, a second injector has been used in advance of the other injector for drawing in atmospheric air so that the apparatus is supplied both with compressed gas and with atmospheric air. Note German Patent DBP 1,095,469.

In such an apparatus, the danger exists that it cannot be used in an atmosphere containing carbon monoxide gas since the carbon monoxide gas would be drawn into the apparatus by the injector. This requires breathing with pure oxygen when poisoning by CO and hydrocyamic acid occurs. On the other hand, the closing of the atmospheric air intake opening changes the capacity of the apparatus and especially the air movement relationship during inhaling and exhaling.

The object of this invention is to avoid the above disadvantages by producing a breathing apparatus using an injector and which can be operated in air contaminated with CO without requiring changes in the gas capacity movement of the injector. In general, the breathing apparatus of this invention uses an injector for drawing in atmospheric air. This is accomplished in that a by-pass line is mounted parallel to the pressure nozzle of the injector, which line communicates with the atmosphere through an opening which can be opened and closed and which is positioned between a shut-off valve in the by-pass line and the intake side of the injector. This means that the intake side of the injector is simply open to the atmosphere or closed off, and when closed, the compressed gas is supplied to the intake side of the injector at the same rate of flow as atmospheric air is drawn in so that the capacity of the injector moved gas remains at the same level.

A further feature of the invention makes it possible to join a cut-off valve in the by-pass valve and the closure for the atmospheric opening so that at all times only one of the two gas openings is open. A throttle in the by-pass line sets the pressure of the gas flowing to the injector. If the injector pressure nozzle is operated at low frequency, such as corresponds to a low breathing volume per minute, then only relatively little outside air is drawn in when the atmospheric air intake is open, and on the other hand, a correspondingly small amount of gas is supplied from the compressed gas source when the atmospheric air intake is closed and the by-pass line is open. Consequently, when a high pressure exists in front of the injector pressure nozzle when the atmospheric air opening is open, a relatively large amount of air is drawn in, and when the atmospheric air intake opening is closed, a correspondingly large amount of gas is supplied and metered by the throttle in the by-pass line.

The size of the throttle according to a further feature of this invention can be made so that the gas volume flowing through the throttle during each respective working pressure corresponds to the volume drawn in by the injector. This means that during a valve change, as when the atmospheric opening is closed and the lay-pass valve is open, no change takes place in the breathing volume per minute.

The means by which the objects of the invention are obtained are described more fully with reference to the accompanying schematic drawing of this invention.

In the portion A of the breathing apparatus, gas such as oxygen flows from the tank 1 through line 2 and pressure control valve 3 into line 4 to branch line 5 and through line 6 to the injector pressure nozzle 7. In branch line 5, gas can flow through line 8 and a throttle valve 9 passed a first valve head 10 through a valve opening 11. The compressed gas flowing through injector pressure nozzle 7 produces in the mixing nozzle 12 a less than atmospheric pressure corresponding to the gas amount flow. This gas flows from portion A of the breathing apparatus into portion B of the apparatus which is of a type shown more fully in U.S. Patent No. 3,039,481 and which does not constitute a part of this invention. Atmospheric air is drawn through atmospheric air intake opening 13 into line 13a and mixing nozzle 12 by reason of the less than atmospheric pressure. In the event that the drawing in of atmospheric air through opening 14 is undesirable, then this opening can be closed by a valve closure member for a second valve composed of a valve head 14 in the form of a manually turnable knob 14. A threaded stem 15 joins the knob 14 and the piston valve head 10 so that, when the opening 13 is closed, the opening 11 is opened. In this position, compressed gas from tank 1 rather than atmospheric air through opening 13 flows through throttle 9 to mixing nozzle 12. The amount of flow of this compressed gas corresponds to the amount of air previously drawn in through opening 13.

Having now described the means by which the objects of the invention are obtained,

Iclaim:

1. In combination with a nutrient gas supply line in a breathing apparatus, and injector means for introducing atmospheric air into said supply line, the improvement comprising a by-pass line connected in parallel with said supply line and said injector means, a first valve in said by-pass line, a second valve between said bypass line and the atmosphere, means joining said first valve to said second valve for closing one valve when the other valve is opened, and a throttle valve in said by-pass line positioned between said first valve and said gas supply line.

2. In the combination of claim 1, said throttle valve having an opening of a size for passing gas at the same rate of flow as the atmospheric air drawn through said second valve.

3. In the combination of claim 2, said second valve being adjustable to vary the opening to the atmosphere.

3 4 4. In the combination of claim 3, further comprising 2,897,833 8/1959 Seeler. a valve head on said first valve. 2,948,292 8/ 1960 Pitt.

5. In the combination of claim 4, said valve head 2,953,160 9/1960 Brazier 137604- XR ll t b k b. comprising a manna y urna le no FOREIGN PATENTS 6. In the combination of claim 5, said first valve comprising a springpressed piston valve head seatable 5 296,605 4/1913 Germany.

on a valve seat when sa1d second valve 1s opened. STANLEY N- GILREATH, Primary Examine"- References Cited WERNER H. SCHROEDER, Assistant Examiner. UNITED STATES PATENTS 10 U S cl X R 2,233,965 3/1941 StIOVnlk 137-3 XR 2 593 046 4 1952 McKee 137 112 XR 137-110, 114, 625.13, 625.29, 630.16, 604,128211

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