Self-contained, underwater breathing apparatus (SCUBA) equipment is used by professional divers, military personnel, and amateur enthusiasts the world over to survive and maneuver underwater for extended periods of time. Such systems often employ a portable source of pressurized air, such as one or more tanks, and associated regulators, lines, mouthpiece, mask, etc. to enable the diver to comfortably breathe air at depths of 100 feet underwater or more.
A problem often associated with open system SCUBA equipment is the exhaust air breathed out by the diver after each breath. This exhaust air normally exits the regulator assembly adjacent the diver's mouth as a large grouping of bubbles that float upward to the surface (hence, “open system” SCUBA). Depending upon the spatial orientation of the diver, the exhaust bubbles can pass directly adjacent the diver's ear, which can be unpleasantly loud and annoying to the diver and can detract from the serenity that the diver might have otherwise enjoyed in the underwater environment. Bubbles passing in front of the diver's mask can also obscure vision and may in some instances cause a safety risk.
Expansive underwater environments, such as that existing under the surface of an ocean, can often have an “ambient” noise level made up of broad-spectrum “white” noise. While this noise can come from a variety of sources such as surface phenomena (e.g., wind, rain) and undersea animal life, a significant proportion of this white noise can often be attributed to bubbles of gas suspended within the water.
Undersea bubbles can be generated in a variety of ways, such as from the natural aeration provided by waves and currents, gasses from animals and plants, and methane or other gasses emitted into the water from underlying strata. This high frequency white noise often represents a normal background level for undersea life, in much the same way that high frequency noise from overhead UV lights or HVAC conduits are not usually noticed by human workers in an office building.
Noise vibrations can be generated when bubbles are formed, when a group of smaller bubbles coalesce into a larger bubble, and when a larger bubble collapses into a group of smaller bubbles. Bubbles also emit noise vibrations when they reach the water surface and the entrapped gas escapes into the atmosphere. It has been found that different sizes of bubbles produce different frequencies when they collapse, and the collapse of different sizes of bubbles release different levels of energy into the surrounding water.
As an extreme case, the so-called Snapping Shrimp (Alpheus heterochaelis) can hunt prey by snapping a specialized claw shut to collapse a cavitation bubble and release large amounts of energy sufficient to stun or kill a small fish. The energy level is so great that sonoluminescence (light generation) and temperatures of around 5,000 degrees Kelvin are produced during the cavitation event.
It follows that, under normal circumstances, undersea wildlife are largely undisturbed by high-frequency, low energy noise conditions, but may become startled and skittish in the presence of lower-frequency, higher energy noise conditions. Unfortunately, when a human diver exhales through existing regulators, large, quickly forming bubbles are produced, and these bubbles release low-frequency energy of the type that tends to scare off wildlife when the diver approaches. By contrast, it has been observed that free divers and divers using closed-circuit rebreathers in which no bubbles are released can normally approach and get very close to wildlife.
Accordingly, various embodiments of the present invention are generally directed to an improved exhaust air transfer device for open system underwater diving.
In accordance with some embodiments, an exemplary device comprises an air supply which provides a supply of air along a supply conduit. A regulator is adapted for engagement with a diver's mouth to receive air from the supply conduit during an inhale cycle and to direct a mixture of water and exhaust air away from the diver along an exhaust conduit during an exhale cycle. An air/water separator (AWS) is coupled to the exhaust conduit to separate the exhaust air from the water in said mixture and to direct the separated exhaust air along an exhaust air conduit.
In further embodiments, the exemplary device incorporates a bubble diffuser coupled to the exhaust air conduit which passes the separated exhaust air as a fine mist of bubbles into the surrounding water. The bubble diffuser may be located on the air supply, such as a tank affixed to the back of the diver. The bubble diffuser may be hinged to generally maintain the diffuser within a desired attitude range irrespective of the attitude of the diver. Alternatively, the bubble diffuser may be a “snorkel-type” member that projects upwardly from the air-water separator and away from the diver's face.
These and other features and advantages of various embodiments can be understood from a review of the following detailed description in conjunction with a review of the accompanying drawings.
Various embodiments of the present invention are generally directed to an underwater breathing system having specially configured exhaust air transfer characteristics.
The diver 100 employs an underwater breathing system 110 to provide a self-contained supply of air for the diver to breathe while he remains below the surface 104. The exemplary breathing system 110 incorporates a number of elements which are functionally represented in
The stage-1 regulator 114 is mounted to the tank 112 and operates to reduce an initial pressure of the compressed air within the tank to a secondary lower pressure. An exemplary initial pressure may be on the order of about 3,000 pounds per square inch, psi, and an exemplary secondary pressure may be on the order of about 150 psi. The tank 112 and regulator 114 may be of a conventional type and are strapped to the back of the diver by way of a buoyancy compensator (BC) vest. Other scuba arrangements may readily be used, including the use of an air hose from a source above the surface 104.
The stage-2 regulator 116 takes a substantially conventional configuration except as modified as required to accommodate various aspects of the exemplary system 110 explained herein. The regulator 116 is held in the diver's mouth to receive air from the air tank 112 and stage-1 regulator 114.
During normal respiration, the diver breathes in fresh air from the air tank 112 through the regulator 116, and breathes out exhaust air through the regulator 116 to the downstream elements 118 and 120. Those skilled in the art will appreciate that the regulator generally includes a series of valves which respond to changes in the pressure of the ambient water in relation to the depth of the diver, the pressure exerted by the diver in breathing in fresh air from the tank, and the pressure exerted by the diver in breathing out the spent exhaust air from his lungs.
In the prior art, the spent exhaust air often exits various ports in the body of the regulator adjacent the diver's face, leading to decreased visibility and increased noise. This can be understood with reference to
In
A main valve 134 is disposed between the air chamber 124 and the exhaust chamber 126. The valve 134 can take the form of a thin rubber membrane which operates as a one-way check valve. As with the valve 132, the valve 134 opens in a single direction when the diver breathes out so that the exhaust air passes through the air chamber 124 to the exhaust chamber 126, and out an exhaust port (or ports) 136 directly into the surrounding water.
Because the exhaust chamber 126 and the port(s) 136 are open to the surrounding water, these elements are typically full of water except when injected with the exhaust air from the diver's lungs when the diver breathes out. When the pressure of the exhaled air falls below the pressure of the surrounding water, the valve 134 closes and the valve 132 opens as the diver takes his next breath. It can be seen from
An adjustment mechanism may be provided to permit the diver to adjust the setpoint, or “cracking pressure” at which the valve 132 opens during inhaling. Such adjustments may be made by the diver by turning a spring biased knob (not separately shown). Generally, a higher cracking pressure requires the diver to exert greater force in inhaling to open the valve and allow the supply air to enter the air chamber 124, whereas a lower cracking pressure allows the diver to inhale air with less effort.
As will be appreciated by those skilled in the art, the valve 134 generally closes in relation to the pressure differential between the exhaust chamber 126 and the air chamber 124; that is, the system uses water pressure in the exhaust chamber 126 to close the valve 134 at the conclusion of each exhale cycle.
In some embodiments the valve 134 is characterized as a thin-film, disc shaped elastomeric membrane with a central portion rigidly affixed to a central dividing wall 138 of the housing that separates the respective chambers 124, 126. A circumferentially extending outer portion of the membrane covers one or more ports (not shown) that extend through the dividing wall.
This outer portion of the membrane is displaced away from the central wall 138 when the pressure in the air chamber 124 is greater than that of the exhaust chamber 126, thereby allowing the air to flow through said ports to the exhaust chamber 126. When the water pressure exceeds the pressure of the exhausted air, the water pressure in the exhaust chamber pushes this outer portion of the valve 134 into a water-tight sealing engagement against said wall 138, thereby closing off the fluidic communication between the respective chambers 124, 126. It will be appreciated that other valve configurations can readily be utilized.
A free-flow condition can arise if there is insufficient pressure differential to close the valve 134 before valve 132 opens. In a free-flow condition, air from the inlet conduit 130 will pass directly through the respective valves 132, 134 and out the port(s) 136. A free-flow condition can be remedied by increasing the setpoint pressure of valve 132. However, during such free-flow conditions large volumes of the stored air can escape to the surrounding water, reducing the available supply of air for use by the diver.
The air/water separator 118 includes a housing (body) 142 that defines an interior air/water separator chamber 144. An inlet port 145 receives the exhaust mixture of water and air from the adapter 140 and injects the same into the chamber 144. Although not shown in
The water exit port 148 is in fluidic communication with the surrounding water. This allows a two-way flow of water between the surrounding water and the separator chamber 144, as well as with the adapter 140 and the exhaust chamber 126 in the regulator 116. It is contemplated that during an exhale operation, water may be directed from the chamber 144 to flow out into the surrounding water, and water may flow back into the chamber 144 at the conclusion of each exhale operation. Although not shown in
In some embodiments, the top of the inlet port 145 is nominally aligned with the bottom of the air outlet port 146, which extends into the interior chamber 144 a selected distance as shown. This provides an air entrapment region 147 that surrounds the outlet port 146 and retains a volume of pressurized exhaust air. The entrapped air may cause the level of water within the chamber 144 to normally reach a steady state level between exhale cycles that is substantially level with the port 146, as shown.
In this way, as the diver exhales a breath, the force required by the diver during such exhalation may be relatively low; that is, just enough to lower the water level to uncover the port 146, thereby allowing the exhaust air to flow freely from port 145 to port 146 and out of the air/water separator 118. A slightly greater exhalation force may be required if the chamber 144 is completely filled with water, since the diver will need to vacate a larger amount of water from the chamber 144 to establish an atmospheric communication path between the respective ports 145, 146. Even if the chamber 144 is completely filled with water, however, it is contemplated that the diver will still be able to exhale easily and without noticeable effort.
Depending on the interior configuration of the chamber 144 and the orientation of the chamber during operation, at various times the chamber may be substantially filled with air, substantially filled with water, or may hold various respective amounts of air and water. In all cases, easy controlled respiration by the diver will be accommodated.
The air/water separator 118 can be mounted to the adapter 140 via a swivel so as to maintain a substantially constant upright vertical orientation irrespective of the orientation of the stage-2 regulator 116. In other embodiments, the air/water separator 118 can be rigidly affixed to the stage-2 regulator so that the orientation of the chamber 144 is set by the orientation angle of the regulator. It has been found that the air/water separator will function properly in substantially all orientations, even when upside down, as the exhaust air can readily flow out the port(s) 148 in this latter condition. However, it is contemplated that optimal results may be obtained when the chamber 144 is oriented along a range from upright vertical to horizontal.
Of particular interest is the flow of the exhaust water through the air/water separator. It will be recalled that the main check valve 134 opens and closes in relation to the differential pressure between the respective chambers 124 and 126. It is generally desirable that water flow into the exhaust chamber 126 at the conclusion of each exhale cycle to prevent initiation of a free-flow condition.
The adapter 140 and air/water separator 118 can be readily configured such that sufficient water is present to immediately fill the chamber 126 at the conclusion of each exhale cycle. To further ensure this fluidic flow, in at least some embodiments one-way check valves 149 may be provisioned in the adapter 140. These valves 149 remain closed when the mixture of water and air pass from the adapter 140 to the chamber 144 during an exhale cycle, and then immediately open at the end of each exhale cycle to permit a back flow of water into the exhaust chamber 126.
Preliminary test results have indicated that the force required to exhale air from the mouthpiece 128 and through an air/water separator such as 118 may be less than that required in a conventional regulator setup as in
A variety of air/water separator configurations can be employed. Exemplary configurations include cylindrical, spherical, and tortuous path configurations. The relative locations of the inlet 146 and outlet 148 can be established to ensure that the exhaust air flows freely regardless of attitude, orientation angle, or relative depths of the regulator 116 and air/water separator 118.
As noted above, the exhaust air during each exhale cycle passes from the air/water separation chamber 118 through the exhaust air port 146 to the bubble diffuser 120. In some embodiments, the bubble diffuser 120 is located on the tank 112 on the diver's back. It will be appreciated that the use of the bubble diffuser with the air/water separator is not necessarily required; for example, in an alternative embodiment a conduit can extend from the air exhaust port 148 in a direction away from the diver's head and terminate in a one-way check valve. In such case, the exhausted air can exit into the surrounding water without the use of a diffusion structure to form a fine mist 151 of bubbles.
A number of spaced apart ports 182 extend through the tub-shaped member 178 and accommodate individual one-way check valves 184, which may take a similar configuration to that of the main one-way check valve 134 discussed in
An interior cover plate 186 spans and covers the ports 182 and includes a number of smaller openings (ports) 188 in fluidic communication with the larger ports 182 and valves 184. A second tub-shaped member 190 mates with the interior cover (diffuser) plate 186 to form a third interior chamber (outlet plenum) 192. The second tub-shaped member 190 may further include an array of multiple spaced apart openings (ports) 194, corresponding to the openings 162 previously depicted in
As further shown in
It has been found through extensive empirical analysis that providing a succession of chambers can provide significant noise reduction. The embodiment of
As noted above, the exhaled air passes through the conduit 174 and into the first chamber 180. The first chamber 180 accumulates the exhaust air from the air/water separator 118 and provides some measure of noise suppression. It will be appreciated that some amount of water may accumulate in the first chamber 180 from time to time, and at other times, the first chamber 180 may be full of air only.
The exhaust air passes from the first chamber 180, through the valves 184 into the second chambers 182 to form relatively large, high energy, low frequency bubbles.
The air from the second chambers 182 pass through the ports 188 into the third chamber as a series of relatively small, low energy, higher frequency bubbles. These bubbles then are further reduced by passing through the diffuser plate portion of member 190 and through the tubes 196, 197 and 198 into the surrounding water as small, low energy, high frequency bubbles, or mist 151. The openings through the tubes 196, 197 and 198 are sized to permit a backflow of water into the chamber 192, and the openings 188 further allow flow of water into the chambers 182. However, the valves 184 are generally configured to restrict flow of water from the second chambers 182 into the first chamber 180. To the extent that water accumulates in the first chamber 180, this water will drain back down the conduit 174 and into the air/water separator 118.
Accordingly, the respective chambers 180, 182 and 192 serve as noise baffling chambers to muffle acoustic noise generated as the exhaust air flows through the bubble diffuser 120. It is contemplated that the energy release in chamber 182 will be further baffled by the air in chamber 180 and the air and water in chamber 192.
The bubbles that pass into the surrounding water will thus have released a substantial amount of energy within the sound chambers and will be close to the ambient bubble energy noise of the water. This will allow the diver to dive with dramatically reduced bubble noise, and allow him to closely approach underwater wildlife without causing a disturbance thereto.
The snorkel-type bubbler 202 is coupled to the air/water separator 200 by way of a flexible or rigid conduit 208. The conduit may be attached to the strap of the diver's mask (see
The air/water separator 201 is shown in greater detail in
The stop valve 206 is characterized as a ball valve with a buoyant float 212 captured within a cage 214. Any suitable shape for the float may be used as desired. Other types of check valves can be used, including weighted check valves that rotate within the chamber 144 to effect sealing of the exit port under different rotational orientations.
An adjustment mechanism 216 is mounted to a lower extent of the air/water separator 201. The adjustment mechanism 216 includes a user activated knob 217 which rotates a shroud cover 218 having apertures 219 extending therethrough. These apertures 219 can be controllably aligned relative to the open ports 148 in the air/water separator housing to regulate a rate of flow of water to/from the chamber 144.
Various interior sidewall contours operate as flow baffles to facilitate the efficient separation and exit of exhaust air out exhaust air port 232 and the flow of water out of exhaust water port 234. The exhaust water port 234 includes a one-way check valve 236 to prevent back flow of water into the downstream portion 230. A two-way normally open water flow port 238 with adjustment mechanism 240 allows controlled regulation of water into and out of the upstream portion 228.
The exhaled air displaces a portion of the water within the chamber through ports 148, allowing the flapper member 254 to move to the open position. It is noted that a portion of the air within the chamber exits through the exposed aperture ports 148 in both
The breathing system as variously embodied herein operates to regulate the respiration of the diver 100 under different diving conditions. With reference again to
While the elevational depth between these two components may be only a few inches, those skilled in the art will nevertheless recognize that the pressure Paws may be significantly greater than the pressure Pb (Paws>Pb). Under these conditions, the exhaust air from the diver 100 will easily pass through the air/water separator 118 and bubbler 120 to the surrounding water, since the exhaust air will normally flow to the lowest available pressure region within the system.
Finally,
It will now be appreciated that the various embodiments disclosed herein can provide a number of benefits. The use of a air/water separator as embodied herein generally enables exhaust air to be separated from exhaust water and directed to a suitable location away from the diver's face and ears, while allowing sufficient back flow of water to the exhaust chamber to ensure free-flow conditions are avoided.
While not required, a bubble diffuser can be utilized to break up large volumes of the exhaust air into a smaller mist or array of bubbles, reducing noise that could scare away underwater wild life, and allowing the diver to not be visually or audibly distracted by the exhausted air.
The system as embodied herein can be mounted to an existing stage-2 regulator or can be incorporated into a new regulator design. The size and shape of the air/water separator can vary and can be made relatively small while still providing sufficient chamber space to handle the expected volumes of exhaust air and to provide a sufficient volume of water back to the stage-2 regulator to close the one-way check valve therein. The use of a check valve within the air/water separator can further provide ease of use even when the diver undergoes changes of depth and/or orientation between breaths.
It will be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this detailed description is illustrative only, and changes may be made in detail, especially in matters of structure and arrangements of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. For example, the particular elements may vary depending on the particular application without departing from the spirit and scope of the claimed invention.
The present application makes a claim of domestic priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/179,620 filed May 19, 2009, which is hereby incorporated by reference.
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Number | Date | Country | |
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61179620 | May 2009 | US |