Diving Vest

Abstract

Self-contained underwater breathing apparatus is provided with a nonstretching jacket extending to the user's waist, inside which a flexible double-walled jacket, connected to a transparent helmet, is pressurized so that it seals water out at waist and sleeve ends, and provides a compliance to allow breathing without any change in the total volume of water displaced by the diver and jacket, since inhalation deflates the flexible bladderlike jacket by approximately the volume inhaled. Improved thermal insulation, ease of breathing, freedom of breathing circuit from water entry, and ready leak detection result.

Description

CROSS REFERENCES TO RELATED APPLICATIONS

Ser. No. 664,448, filed Aug. 30, 1967, Diving Apparatus, Frederick A. Parker, now U.S. Pat. No. 3,515,133.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains to self-contained underwater breathing apparatus.

2. Description of the Prior Art

The old conventional diving dress surrounds the diver with a flexible impervious suit hermetically connected to a helmet provided with air under pressure from a hose, and a bleeder valve which permits excess air to leak out at such a rate that the helmet is kept clear of water. However, the suit is not fully inflated in normal operation. Indeed, under emergencies so grave as to justify the risk of rapid decompression it was known to close down on the bleeder valve to cause the suit to become fully inflated and float the diver to the surface--a procedure sometimes known as "blowing the suit".

More modern self-contained breathing apparatus provides varying degrees of enclosure, from the simple mouthpiece which leaves the diver entirely exposed to surrounding water, to completely enclosing suits which may be lined with thermal insulating material and which, for better thermal insulation, may provide an additional small volume of air to keep external water pressure from forcing the diver into too good thermal contact with the suit. The use of an inflated seal to keep water from entering the helmet around the neck line is also known. None of the prior art provides an air pocket surrounding the diver's chest region so that he may breathe with his chest displacing low-viscosity air rather than the much higher viscosity water, which latter imposes a great physical burden for its displacement by the chest movements.

SUMMARY OF THE INVENTION

I provide the diver with a nonstretching short-sleeved (or jerkin-style) jacket extending to his waist, and large enough to provide room for the fullest possible expansion of his lungs. Inside the jacket I provide a double-walled bladder vest which is connected to a helmet and so becomes inflated with air (or other breathable mixture) at the pressure existing inside the helmet. Its expansion around the waist causes it to press against the lower edge of the jacket (to which it may, indeed, be sealed) and against the diver's body at the waist line, forming a watertight seal. In the simplest embodiment of my invention, the quality of the breathable mixture may be maintained by means for automatic absorption of carbon dioxide produced by the diver and for automatic addition of oxygen as it is consumed, with negligible change in the total volume of breathing mixture in the apparatus and the diver's lungs. As the diver inhales, his lungs expand, displacing breathing mixture from the bladder vest in the same volume as he inhales. As he exhales, his lungs contract, adding breathing mixture to the bladder vest in the same volume as he exhales. Thus the diver's breathing is accomplished without change in the total volume of water that he and his gear displace. In other words, his chest moves in and out with air on its outer side, without the necessity of forcing dense and viscous water to move. His breathing effort is thus much reduced. Furthermore, the external air layer provides good thermal insulation; any leak in the system will be readily detected by emerging air bubbles while any water which has entered through the leak is still well down in the bladder vest, far from the breathing circuits; and the diver's extremities (which do not expand and contract with his breathing) are left free for unrestricted movement.

In my copending disclosure of reference, I teach the use of a diaphragm pump operated by water pressure to provide powered assistance in breathing. My present invention may be applied to this, without change in principle, by including in the bladder vest flexible inserts (which may conveniently have the form of tubes extending longitudinally into the air-filled volume of the bladder vest) which serve as reservoirs of the water used to drive the pump. The effect is the same: when the pump diaphragm moves to displace breathing mixture into the diver's lungs, a volume of water is drawn from the tubes which is equal to the volume of air displaced. Consequently the total volume of the bladder vest is reduced by the same amount as the diver's chest expands. When the pump diaphragm is displaced in the opposite direction to draw air from the diver's lungs, it displaces water into the tubes in a volume equal to the amount by which the diver's lungs contract, increasing the total bladder vest volume by the proper amount to maintain constant the total volume of external water displaced by the diver plus his suit.

It is possible, within the scope of the invention, to extend the nonstretching outer garment to include the diver's extremities, and similarly extend the bladder garment inside it, to provide thermal insulation for the entire body. However, the almost inevitable volume changes not connected with breathing which would be produced by motion of the extremities would appear to render this stratagem less desirable than the embodiments first described, although it would be possible to separate the bladder portions surrounding the extremities and connect them with the bladder vest proper through small orifices which would damp the transmission of such volume changes to the bladder vest proper, while still providing low but adequate inflation of the insulating jackets around the extremities.

While my invention has been described particularly in connection with self-contained breathing apparatus, it is evident that one might, as, for example, in operating close to an underwater installation provided with sources of oxygen, provide oxygen through a hose which could be smaller and less cumbersome than the hose of the conventional diving dress. Such a diving apparatus would obviously not be self-contained. But so long as the volume of gas supplied in a given time were small compared with the diver's tidal volume breathed during the same time, the application and benefits of my invention would be the same, since the volume of breathing mixture in the apparatus would be substantially constant, changing only slowly if at all.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents schematically, partly in section, an embodiment of my invention;

FIG. 2 represents schematically, partly in section, an alternative embodiment of my invention; and

FIG. 3 represents for clarity an alternate position of one of the valves represented in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, there is represented a helmet 12, which may preferably be generally spherical in shape and of transparent plastic. At its edge 14 it is sealed by any convenient means to the outer wall 16 of double-walled bladder vest 18, whose inner wall 20 is separate from wall 16 in order that its inner space may be in communication with the space inside helmet 12. This bladder vest 18 surrounds the body of the diver 22 down as far as his waist 24, encompassing the part of the body which expands and contracts during breathing. A nonstretching outer garment 26 surrounds vest 18 closely enough so that expansion of vest 18 by internal pressure can form watertight seals between vest 18 and the diver's body, as at waist 24.

The breathing mixture is circulated and maintained in quality and pressure by the following components. Oral-nasal cavity 28 of conventional design is connected with the diver's mouth and nose. It is also connected to check valve 30, which vents exhaled air into the helmet 12 and (through its connection with the interior of vest 18) into the interior space of vest 18, so that vest 18 inflates and increases in volume by the same amount as the decrease in the volume occupied by the diver's trunk. When the diver inhales, air flows from the helmet 12 (and the interior of vest 18) through check valve 32 into housing 34 (which serves as the inlet connection to the quality maintaining means), where it encounters oxygen sensor 36 (which may be a fuel cell type sensor of the kind described in U.S. Pat. No. 3,149,921 of Warner). The output of oxygen sensor 36 is electrical, and is connected to open solenoid valve if the partial pressure of oxygen is subnormal, i.e. below a value predetermined as normal. This permits oxygen to flow from oxygen store 40 into the pipe 42 connected to the outlet end of housing 34. After passing oxygen sensor 36, the air passes through a carbon dioxide absorbent 44 in housing 34, into pipe 42 where it is mixed with any addition of oxygen which may have come from store 40. A regulating valve 46 (which regulates with respect to the pressure of the external ambient water which is predetermined by the diver's depth) controls the flow of inert diluent gas (which may be nitrogen or argon or helium) from store 48 as required to maintain the pressure inside the system sufficiently above the external water pressure to insure the inflation of bladder vest 18. A pressure differential of the order of a pound per square inch is sufficient for this purpose. To relieve any excess of pressure (as may occur if the diver ascends) relief valve 50, which operates with respect to the pressure of the external ambient water, is connected between pipe 42 and the outside. It is set to vent at a pressure slightly greater than that for which regulating valve 46 is set. The air drawn through housing 34 passes through pipe 42 (the outlet connection of the quality maintaining means), through check valve 52, to oral-nasal cavity 28, where it is inhaled by the diver. As the diver inhales, and his lungs expand, they move the inside wall 20 of vest 18, reducing the interior volume of the vest by the same volume as the diver has inhaled.

Since the change in volume of the vest 18 is equal and opposite to the change in volume of the diver's trunk during both inhalation and exhalation, the total volume of water displaced by the diver and the apparatus will remain constant. Thus it is possible to maintain in the helmet a pressure measurably above the external water pressure (insuring that any leakage will be primarily outward in the form of visible bubbles) without requiring the diver's lungs, and chest muscles, to work against that pressure difference. The work the diver must do is primarily that required to force the inhaled air through the check valves 32 and 52 and the absorbent 44, which is no greater than if he were using the same equipment in air (or, for example, an unbreathable atmosphere).

In practice, to avoid danger of accidental collapse of the bladder vest 18 under pressure of the diver's body against it, it may be desirable to provide tubes extending from the open neck region into various parts of the interior of the vest, to insure that breathing mixture will reach each part of the vest and expand it appropriately.

For use of power-assisted breathing apparatus, as described in my copending application of reference, my invention may be applied as represented by FIG. 2.

Since many of the elements of FIG. 1 appear also in FIG. 2, of the same nature and performing the same function, those elements have been given the same reference numbers in both figures. Thus, for example oral-nasal cavity 28, check valve 30, and check valve 52 serve to connect to the diver's respiratory system and to steer his exhalations and inhalations to appropriate parts of the apparatus; oxygen store 40 supplies oxygen as required through solenoid valve 38, which is controlled by oxygen sensor 36; diluent gas source 48 supplies diluent through regulator valve 46; relief valve 50 relieves any excessive pressure; and helmet 12 and nonstretching outer garment 26 serve substantially the same functions in both embodiments.

The additions which particularly distinguish the embodiment of FIG. 2 from the simpler one of FIG. 1 are as follows: A hydraulically operated piston pump generally denoted as 54 comprises a cylinder 56, a piston 58 movable therein, sealed hermetically with respect to the cylinder walls by a flexible sleeve 60; and the piston 58 is biased toward the bottom of the cylinder 56 (as represented by spring 62 so that, in the absence of any opposing pressure against it, it tends to move downward and draw through check valve 64 and pipe 66 breathing mixture from the interior of helmet 12. Such opposing pressure is provided, when required to force breathing mixture through carbon dioxide absorbent and thence through pipe 68 and check valve 52 into oral-nasal cavity 28, by pump 70, which is driven by motor 72, powered by battery 74. A spring-loaded hydraulic accumulator 76 is connected at the discharge side of pump 70 to even out the load on it. The application of hydraulic pressure from hydraulic pump 70 to diaphragm 58 of piston pump 54 is controlled by three-way valve 78, which is represented in a position to permit the application of pressure through pipe 80 to the lower side of diaphragm 58. When valve 78 is rotated (by means to be described) to the alternate position represented in FIG. 3, piston 58 is moved downward, in compliance with the force exerted by spring 62, drawing breathing mixture from the helmet 12 through pipe 66 and check valve 64, as has been described; and its downward movement forces water from its under side through pipe 80, through valve 78 in the position represented in FIG. 3, and thence through pipe 82 into header 84, which is connected to water tubes 86, which form a part of bladder vest 88, which is a cognate of bladder vest 18 of FIG. 1. The use of hydraulically operated piston pump 54 produces an alteration in the total volume of the part of the entire system which contains breathing mixture; when the diver 22 inhales as the pump piston 58 moves upward, his trunk expands without there being any provision of a corresponding flow of an equal volume of breathing mixture out of the portion of bladder vest 88 which contains breathing mixture; when diver 22 exhales as pump piston 58 moves downward, there is no provision for adding to the breathing-mixture part of bladder vest 88 a volume of air equal to the reduction in the volume of the diver's trunk. But the operation of pump 54 causes the displacement of an equal volume of water. Therefore the simple bladder vest 18 of FIG. 1 is modified by the addition of water tubes 86, connected by header 84, forming bladder vest 88 whose total volume may be appropriately adjusted by influx and efflux of water into its water compartments. Thus the influx of water via pipe 82, when the diver 22 exhales, increases the total volume of bladder vest 88 by an amount equal to the amount by which the diver's trunk volume has been reduced. Similarly, when the diver inhales, water flows through pipe 90 and valve 92 through the pump 70 and valve 78 and pipe 80 into cylinder 56 in an amount equal to the increase in the diver's trunk volume. Valve 92 is normally left in the position shown, but may be turned in initiating operation of the apparatus so that it bleeds air out of the system through check valve 94. Similarly, check valve 96 serves to prime the system with water on starting up. Relief valve 98 serves to relieve any excessive water pressure developed.

The description of FIG. 2 is complete except for the explanation of how valve 78 is operated in accordance with the diver's desire to inhale or exhale. This is accomplished as follows: A diaphragm-type pressure difference sensor 100 is connected between pipes 68 and 66. Its diaphragm is connected to actuate a switch 102 (represented as a rectangle; it may be of various forms, and may be located inside the housing in close proximity of the diaphragm of sensor 100). Switch 102 is connected to rotator 104, which is mechanically connected to rotate valve 78. Since only a quarter of a circle of rotation is required, rotator 104 (although it might be a conventional commutator-type motor equipped with limit switches to stop it at its desired extremes of rotation) may be a simple rotary solenoid or equivalent. It may be constructed to require application of potential only to move it from a first position to a second, and have a spring to return it to the first position as soon as potential is removed. The nature of the contact arrangement of switch 102 will obviously depend upon the exact nature of rotator 104. An arrow indicates that 102 and 104 are connected to battery 74, to derive necessary power from it. The function required is simply that, when the diver 22 inhales, drawing breathing mixture through check valve 52 and reducing the pressure on the top side of the diaphragm of sensor 100, switch 102 functions in such a way that rotator 104 turns valve 78 to the position represented in FIG. 2; and when the diver exhales, discharging his exhalation out through check valve 30 and causing an increase in pressure in pipe 66, raising the diaphragm of sensor 100, switch 102 functions in such a way that rotator 104 turns valve 78 to the position represented in FIG. 3. For detailed description of the construction and mode of operation of power-assisted breathing systems of this kind, reference is made to the application cited in the cross reference. Briefly, the effect of the various operations is that the diver's initial effort to inhale causes the pump 56 to pump breathing mixture to him; and his initial effort to exhale causes pump 56 to draw off breathing mixture from him; and simultaneously the volume of water in the water compartments 86 plus 84 of bladder vest 88 is adjusted to compensate for the required change in the diver's trunk volume, preserving a constant total volume inside nonstretchable garment 26.

To generalize the essentials of the two embodiments described in order that they may be subsumed under one generic description, it appears desirable to recapitulate.

Clearly, the volume-balancing of inhalation and exhalation with changes in volume of the bladder vest is useful primarily in a system in which the volume of gas approximates constancy--in other words, in which any gas supplied in a given period is small compared with the total volume of the diver's breathing during the same period. Sources of oxygen and diluent gas, and carbon dioxide remover, together with regulating means for them and for regulating breathing mixture at the requisite pressure may be generalized as quality maintaining means. The bladder-vest is generically a double-walled flexible inner garment; it must be suitable to surround the diver's body from helmet to waist, although it may extend further than that. Its outer edge is sealed to the edge of the helmet in the sense that it provides a hermetic seal; a clamping ring or other conventional removable means may constitute such a seal; the term "seal" here not being used to indicate permanence in the sense of a cemented seal. The outer nonstretchable jacket may be generalized as a nonstretching outer garment. In the embodiment of FIG. 2, in which the vest 88 is provided with a header 84 and tubes 86 connected to the header 84, the header and tubes form a flexible water chamber which is part of vest 88, but closed to flow between itself and the remainder of the interior of vest 88.

Claims

I claim:

1. In an underwater breathing apparatus in which the volume of gas supplied in a given period is small compared with the total volume inhaled and exhaled by the diver during the same period, the improvement comprising:

A helmet connected through a first check valve for flow of breathing mixture to the inlet connection;

Quality-maintaining means to maintain the breathable quality of breathing mixture in the helmet and to maintain a pressure of breathing mixture therein approximately equal to the pressure of external ambient water, having separate inlet and outlet connections, having connected between the said inlet and outlet connections carbon dioxide absorbing means in series with oxygen replenishment means automatically controlled to maintain a predetermined partial pressure of oxygen in the breathing mixture; and having a source of inert diluent gas controlled to maintain a predetermined total pressure of breathing mixture;

An oral-nasal cavity within the helmet, connected through a second check valve to the outlet connection of the quality maintaining means to permit flow of breathing mixture from the outlet connection to the oral-nasal cavity; and connected through a third check valve to the space within the helmet to permit flow of exhaled breathing mixture from the oral-nasal cavity to the space within the helmet;

A double-walled flexible inner garment adapted to surround the diver's body from the helmet to his waist, its outer wall being sealed to the edge of the helmet, its interior being connected to the interior of the helmet;

A nonstretching outer garment adapted to surround the double-walled flexible inner garment, fitting the inner garment sufficiently closely so that inflation of the latter can cause the inner garment to press against the interior of the outer garment and form a seal between the outer garment and the body of the diver.

2. The improvement claimed in claim 1 in which the therein said inner garment further comprises a flexible water chamber closed to flow between it and the remainder of the interior of the inner garment; and the therein said quality maintaining means comprises a hydraulically operated breathing mixture pump whose hydraulic drive connection is connected to the said flexible water chamber, the said pump being so constructed and connected that the volume of breathing mixture it displaces to the oral-nasal cavity is equal to the volume of water it displaces from the flexible water chamber, and the volume of breathing mixture it displaces from the helmet is equal to the volume of water it displaces to the flexible water chamber.