A self-contained open-circuit breathing apparatus for use within a body of water naturally containing dissolved air. The apparatus is adapted to provide breathable air to a diver. The apparatus comprises an inlet means for extracting a quantity of water from the body of water. It further comprises a separator for separating the dissolved air from the quantity of water, thereby obtaining the breathable air. The apparatus further comprises a first outlet means for expelling the separated water back into the body of water, and a second outlet means for removing the breathable air and supplying it for breathing. The air is supplied so as to enable all of it to be expelled back into the body of water after it has been breathed.

FIELD OF THE INVENTION

This invention relates to self-contained underwater breathing apparatus and methods.

BACKGROUND OF THE INVENTION

Among known underwater respiration devices are those that supply air via a conduit from the Earth's atmosphere to a submerged user or, in the case of SCUBA, comprise a portable tank with breathable compressed gases including oxygen. In open-circuit SCUBA systems, the breathed, exhaust gas is discarded in the form of bubbles with each breath. Closed-circuit systems recycle the exhaust gas by adding oxygen to and removing carbon dioxide from exhaled breaths.

U.S. Pat. No. 3,333,583 discloses a closed-circuit underwater respiration device which purifies and recycles a diver's exhaled breath. This purification is achieved by driving the exhaust breath through gas permeable tubes, which are surrounded by a current of seawater. Oxygen dissolved in the seawater then passively diffuses across the tubes into the exhaled breath while carbon dioxide similarly diffuses out. The breath is then supplied to the diver for breathing and the process is repeated indefinitely.

U.S. Pat. No. 3,656,276 discloses a closed-circuit method and apparatus for reoxygenating and removing carbon dioxide from stale, breathed air in an underwater habitat by mixing it with seawater in intimate and agitated contact, and subsequently separating the refreshed air from the seawater.

SUMMARY OF THE INVENTION

The present invention suggests a self-contained breathing apparatus that operates in an open-circuit SCUBA-like manner where the user's exhaled breath is expelled into the body of water in the form of bubbles. However, the apparatus of the present invention differs from conventional SCUBA in that it does not require a portable tank of breathable compressed gases.

The apparatus of the present invention comprises an inlet means for extracting a quantity of water from said body of water, a separator for separating said dissolved air from said quantity of water thereby obtaining said breathable air, a first outlet means for expelling the separated water back into said body of water, and a second outlet means for removing said breathable air from the separator and supplying it for breathing.

The apparatus is for use within any body of water that naturally contains dissolved air and it obtains breathable air directly from the surrounding water in which it is submerged. The body of water may be an ocean, lake, pond, river or any such body having breathing marine life such as fish.

The present invention further suggests a method for providing breathable air from a body of water naturally containing dissolved air comprising the steps of drawing an amount of water from said body of water, separating said dissolved air from the drawn water and thereby obtaining said breathable air, expelling the separated water and supplying the separated air for breathing, and expelling the air back into said body of water after it has been breathed.

An apparatus operating according to the method of the present invention may be relatively light and uncomplicated. It also eliminates the need to carry a set amount of breathing air, one of the primary factors normally limiting the amount of time that can be spent underwater. Also, since in the apparatus of the present invention, the separated air already meets a user's pressure requirements for breathing, the apparatus eliminates the need for a pressure regulator, which is necessary in SCUBA to lower the pressure of the compressed gases in the tank.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1schematically shows a self-contained breathing apparatus2according to the present invention. The apparatus2is adapted to provide breathable air and is designed for use within any body of water naturally containing dissolved air, such as an ocean, lake, pond, river and the like. As can be seen inFIG. 1, the apparatus2comprises two inlet means4aand4bfor extracting a quantity of water from the body of water, but may have one or many such inlet means. The inlet means4a,4bmay be any kind of conduit through which liquid can be conducted.

The apparatus2further comprises a separator6for separating the dissolved air from the extracted quantity of water conducted thereto via the inlet means4aand4b. The separator6has a housing and also includes first outlet means8aand8bfor expelling the separated water back into the body of water, and second outlet means10aand10bfor conducting the separated air out from the separator6. The separator6may include one or many first and second outlet means, which may be any kind of conduit through which fluids can be conducted.

The second outlet means10aand10bmay include valves that only permit air to be conducted further. These valves may be any kind of mechanism preventing the passage of water but allowing the passage of air. One possible option for such a mechanism includes providing a portion of the outlet means10aand10bthat tapers to a smaller cross-sectional area and also includes a floating body, similar to a ping pong ball, for example, having a larger cross-sectional area and, consequently, being capable of blocking the movement of water without hindering the passage of air. Since the separated air in the separator6rises above the water, the separator6may be designed to ensure that the outlet means10aand10band valves are located on the upper part of the separator6. In addition, a plurality of outlets with valves can be positioned at various points on the separator6, thereby ensuring that at least one of them is always pointing up and in contact with the rising separated air. In this way, the air rises towards the highest outlets10a,10b, which conduct the air further, either directly to a location for breathing or to an air bag14, which serves as a storage reservoir for breathable air.

The air bag14may be any kind of storage reservoir, and may also be part of another body such as a floatation jacket or depth-adjusting bladder, thereby simultaneously serving multiple purposes.

The apparatus2further comprises a pump16to pump water into the separator6via the inlet means4aand4b. The pump16may be any mechanism creating a flow of water through the separator6such as by drawing water in via one or more of the inlet means4aand4band/or ejecting water out via one or more of the outlet means8aand8b. The pump16is motorized and may be powered electrically, using batteries for example, or mechanically, such as by using the efforts of a user.

The apparatus2and method by which it functions can be employed in a variety of settings to provide breathable air to living beings such as in submersible quarters, e.g. submarines or underwater habitats, as well as in diving gear for use by individuals. The apparatus2may further be used to provide such breathable air for uses other than breathing, e.g. for supplying air to combustion engines.

FIG. 2illustrates a specific use of the apparatus2according to the present invention designed for an individual diver20as in the case of SCUBA. In this use, the apparatus2includes batteries17to supply electrical power thereto, which are arranged on a belt18worn by the diver20. The belt18may also carry lead diving weights to provide the diver20with the additional weight needed to counter his natural buoyancy, or alternatively, the batteries may also provide or contribute to this needed weight. The diver20also wears the air bag14, which simultaneously serves as a thermal and flotation jacket.

FIG. 3is a functional diagram schematically illustrating how an apparatus2according to the present invention may operate for an individual diver in an ocean. Seawater from the ocean is drawn into the apparatus2via the inlet means (not shown) by the pump16and enters the separator6.

The separator6separates the dissolved air from the water by any known method of physical separation or combination thereof. Most such methods are based on passing the water across a pressure drop and examples include, but are not limited to, cavitation, volumetric increase, and the use of centrifugal force. Cavitation involves passing the water across a hydrofoil such as a propeller, which, due to its design, creates a lower pressure region on its trailing edge, resulting in the release of dissolved air. Volumetric increase entails passing the water from a smaller to a larger space, thus increasing the volume of the water and decreasing the pressure applied thereto, thereby causing the release of the dissolved air. The use of centrifugal force involves rotating the water at such a speed that the heavier water moves farther away from the axis of rotation than the lighter dissolved air, consequently resulting in its separation.

The air-depleted seawater is expelled from the apparatus2back into the ocean via the first outlet means (not shown). The air released by separation is breathable and is, preferably, conducted to the air bag14via the second outlet means (not shown), wherefrom it is supplied to the diver. Having been breathed by the diver, the air is expelled into the ocean. If the diver requires less air than is conducted to the air bag14by the separator6, the air bag14stores the air. When the air bag fills completely, the air separator6shuts down until the diver has used a predetermined fraction of the air in the bag14, at which point the separator4resumes supplying air to the air bag14. In this way, the apparatus expends less power. In the case of an individual diver, it is preferable for the air bag14to be flexible and inflatable but at the same time made from a durable material to minimize its likelihood of being damaged since the diver draws his breath from the air bag14. In the case of a submarine or underwater habitat, a storage reservoir such as an air bag14may not be necessary and the breathable air can be directly supplied to such spaces.

Reverting back toFIG. 1, the separator6shown utilizes two propellers12aand12bto separate air from water by cavitation. The propellers12aand12balso contribute to separation by imparting a centrifugal force on the water. In addition, the propellers12aand12bdrive the water through the separator6, thereby acting as axial pumps, which may be used in place of or in conjunction with the pump16. The separator6may also comprise air tubes13to attract rising bubbles of air as they are separated from the water and convey them to the outlets10aand10b. The air tubes13may be made of a material (e.g. stainless steel) adapted to attract air bubbles based on the coalescence effect.

The amount of breathing air required by a diver depends on many factors such as diving depth and extent of physical exertion and also varies from one individual to the next. Nonetheless, most divers, even during their highest exertion, require no more than 25 liters of air per minute, and so the separator6is designed to provide at least this minimum amount of air at this rate. While the apparatus2may be of various sizes, one possible example for use by an individual diver includes the apparatus2having separator6cylindrical in shape and approximately 10 inches in diameter at its base and 20 inches long. For a separator6having these dimensions and two cavitating propellers spanning its inner diameter, at most depths, the pump16will need to provide about 2000 liters of average seawater per minute to the separator6in order to produce the aforementioned minimum amount of air required by the diver.

As can be seen inFIGS. 2 and 3, the apparatus2according to the present invention may include a small reserve tank22of compressed breathable gases to be used in the case of a malfunction, which prevents or hinders the providing of air.

Also, as shown inFIG. 3, the apparatus2may include an air purifying mechanism, such as a scrubber24, as known in the art, adapted to reduce the amount of carbon dioxide and/or other undesirable gases present within the air bag14and to thereby enable delivery of a more healthy supply of breathable air to the diver20.

Reverting toFIG. 1, the apparatus2may also provide a diver or other submersible with propulsion by directing the flow of water via the first outlet means8aand8bin a desired manner. Provided with a means for varying their direction separately or in unison, the first outlet means8aand8bcan be oriented to create thrust at a user's command and propel the diver or submersible in a desired direction. In this way, energy that would otherwise be expended to propel a diver or submersible is saved.

It should be understood that the above described embodiments are only examples of a self-contained open-circuit underwater breathing apparatus and method for using same according to the present invention, and that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art. For example, the apparatus may be used in underwater drilling, where a supply of air may be necessary.