Abstract:
A diaphragm and exhaust valve for an underwater breathing apparatus second stage regulator are combined to conserve breathing gas during all orientations of the diver, to provide smooth operation of the diaphragm without interference from exhaust bubbles, and to provide unrestricted exhaust flow. In addition, the diaphragm and exhaust valve are fabricated and installed as a single component.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to regulators for underwater breathing apparatus and more particularly to the diaphragm and exhaust valve of second stage regulators. 
     2. Description of the Prior Art 
     In a typical underwater breathing apparatus, air or other breathable gas is supplied to a diver from a high pressure tank via a two stage regulating system. The regulator first stage is mounted to the high pressure tank valve and functions to reduce tank gas pressure to about 150 psi above ambient pressure. The tank and regulator first stage are carried by the diver on his back. A flexible hose conduit supplies the reduced pressure gas to a regulator second stage held by the diver&#39;s mouth with a mouthpiece. The second stage is a demand regulating device which opens to supply breathing gas at ambient pressure in response to inhalation effort. Provision is also made to exhaust exhaled gas through the mouthpiece into the water. 
     Inhalation suction pressure is sensed by a diaphragm within the second stage that cooperates with a lever to open a valve which controls the flow of gas to the diver. Whenever the diver stops breathing, or exhales, the diaphragm responds to the lack of inhalation suction by stopping the flow of gas. A separate exhaust valve is provided to permit the escape of exhaled gases. The exhaust valve, due to physical and dimensional constraints, is a component which is separate from the diaphragm and is typically located several inches away from the diaphragm. 
     The separation of the diaphragm and exhaust valve in the prior art is a shortcoming because whenever the swimming diver is oriented so that the exhaust valve is over (closer to the water surface than) the diaphragm, the exhaust valve is at a slightly lower pressure in the water than the diaphragm, and a sensitive diaphragm will respond to the slight loss of pressure through the exhaust valve by inadvertently turning &#34;on&#34; the regulator which results in an unwanted loss of breathing gas. The larger the separating distance between exhaust valve and diaphragm, the greater the waste of breathing gas. An object of the present invention is to close the spacing between the exhaust valve and diaphragm and thereby prevent the unnecessary waste of breathing gas. 
     Some configurations of prior art place the exhaust valve at the center of the diaphragm or actually combine the functions of diaphragm and exhaust valve. Such a configuration is disclosed in the inventor&#39;s U.S. Pat. No. 4,297,998 issued Nov. 3, 1981 entitled PILOT CONTROLLED REGULATOR SECOND STAGE. In this type of configuration, typically the flow of exhaled gases past the exhaust valve generates numerous bubbles as water is displaced by the expanding gas. These bubbles set up a lingering turbulence which can remain even after exhalation is completed and a new inhalation cycle has been initiated. Such turbulence disrupts the smooth operation of the mutually located, exposed diaphragm. Another object of the present invention is to isolate the closely spaced diaphragm and exhaust valve from each other such that exhaust bubbles do not interfere with the smooth operation of the diaphragm. 
     Another shortcoming of prior art is that the flow of exhaled gases is restricted by the limited size of the exhaust valve and related passages. Another object of the present invention is to provide an exhaust valve with flow passages which do not restrict the flow of exhaled gases. 
     Another shortcoming of prior art is that the diaphragm and exhaust valve are separate components which must be individually fabricated and mounted. An object of the present invention is to provide a diaphragm and exhaust valve which are a single component. 
     SUMMARY OF THE INVENTION 
     The objective of the present invention is to provide a diaphragm and exhaust valve system which conserves breathing gas during all orientations of the diver, and in which the diaphragm and exhaust valve are in close proximity to one another. 
     Another objective of the present invention is to provide a diaphragm and exhaust valve system which enables the diaphragm to function smoothly and without interference from exhaust bubbles. 
     Another objective of the present invention is to provide an exhaust valve with unrestricted flow passages. 
     Another objective of the present invention is to provide a diaphragm and exhaust valve which are fabricated and mounted as a single component. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A detailed description of the invention will be made with reference to the accompanying drawings wherein like numerals designate corresponding parts in the several figures. 
     FIG. 1 is a pictorial view of an underwater breathing apparatus having a regulator second stage incorporating the inventive diaphragm and exhaust valve system. 
     FIG. 2 is a sectional side view of the regulator second stage as seen along the line A--A of FIG. 1, and showing the inventive system with the diaphragm in the neutral or &#34;regulator off&#34; condition and the exhaust valve in the &#34;closed&#34; position. The exhaust valve in the &#34;open&#34; position is represented in the figure by dot-dash phantom lines. 
     FIG. 3 is the same side view of the inventive system shown in FIG. 2, but with the diaphragm in the depressed or &#34;regulator on&#34; condition. A purge button in the &#34;pushed&#34; condition is represented in the figure by dot-dash phantom lines. 
     FIG. 4 is a sectional top view of the inventive device as viewed in the direction B--B of FIG. 3. The exhaust opening, which is covered by the exhaust valve, is shown in the figure by a dash line. 
     FIG. 5 is an exploded perspective view of the regulator second stage incorporating the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following detailed description is of the best presently contemplated mode of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention since the scope of the invention is best defined by the appended claims. 
     In FIG. 1 there is shown an underwater breathing apparatus 9 incorporating a demand regulator 10 in accordance with the present invention. The apparatus 9 includes a supply tank 11 containing breathable gas under high pressure. Attached to tank 11 is a regulator first stage 12 which provides the breathable gas at a reduced pressure, typically 150 psi above ambient, to a conduit 13. The regulator second stage 10 is connected to the other end of the conduit 13 via an inlet port 14, and functions to deliver breathable gas at ambient pressure to a diver via a mouthpiece outlet port 15 upon inhalation demand. 
     As evident in FIG. 1, the body 17 of the regulator 10 includes a cylindrical section 17a that defines an interior chamber 18 (FIGS. 2 and 3). A flow control valve housing 19 is situated within the body section 17a. A conventional valve within the housing 19 controls the flow of breathable gas from an inlet port 14 to the mouthpiece outlet port 15. 
     As evident in FIGS. 1 and 2, rigidly attached to the body section 17a is a generally cylindrical housing 17b that contains the inventive diaphragm and exhaust valve system. This diaphragm and exhaust valve housing 17b includes a cylindrical outer wall 23 having one or more openings 24 that admit water into a chamber 25. 
     Contained within the outer wall 23 is a separating wall 37 (best described below in connection with FIG. 5) which separates the interior chamber 18 from the chamber 25. Also within the outer wall 23 is a diaphragm chamber wall member 30 which encompasses a chamber 31 that is enclosed at one end 31a by the diaphragm 22a and at the other end 31b by a flexible cover 32. The cover 32 has one or more openings 34 that admit water into the chamber 31. 
     The diaphragm 22a is of generally circular, concave configuration and is made of a resilient, highly flexible rubber or plastic material. The diaphragm 22a is firmly clamped in place along a peripheral bead 22c which mates with the wall member 30. At the center of the diaphragm 22a is a rigid cylindrical plug 26 which makes sliding contact (at 26a) with an arm 20. The arm 20 links the diaphragm 22a with the flow control valve within the housing 19. 
     The diaphragm 22a is shown in FIG. 2 in the neutral or relaxed position. The arm 20 is thereby also in its neutral position with the result that the flow valve within the housing 19 is closed. Such a neutral position of the diaphragm 22a is attained when the pressures of the interior chamber 18 and the exterior chamber 31 are equal. 
     During inhalation, the pressure in the chamber 18 is reduced, causing the diaphragm 22a to move in the direction of the arrow 40 (FIG. 3). As a result, the diaphragm 22a is displaced to an intermediate position 22a&#39; and the lever 20 is correspondingly moved to a position 20&#39;. Movement of the lever 20 to the position 20&#39; causes the flow valve within the housing 19 to open, thereby flowing breathing gas into the chamber 18 and subsequently through the mouthpiece outlet port 15. When inhalation is stopped, the pressures of the chambers 31 and 18 on both sides of the diaphragm 22a are once again equal. The natural resilience of the diaphragm 22a returns it to its neutral position, with a corresponding return of the lever 20 to its neutral position. In this manner breathable gas is supplied to the diver only on inhalation demand. 
     The cover 32 is generally circular and is made of a resilient rubber or plastic material. An interlocking arrangement between a peripheral flange 30b at the end of a cylindrical portion of the wall member 30 and a cap member 36 firmly holds the cover 32 in place. 
     Mounted in the center of the cover 32 is a generally conical, rigid purge button 33. Manually pushing the button 33 inward flexes the cover 32 so that the button 33 is moved to an intermediate position 33&#39; shown in phantom in FIG. 3. Such an inward movement of the purge button 33 will cause a corresponding displacement of the diaphragm 22a and the lower 20, thereby opening the flow valve within housing 19. The resultant flow of breathing gas purges the regulator 10. 
     The exhaust valve flap 22b is of generally flat semicircular shape and is made of a resilient, highly flexible rubber or plastic material. The exhaust valve flap 22b closes the passage formed between the chambers 18 and 25 by sealing along an edge 28 of the separating wall 37. As shown in FIG. 4, the exhaust valve flap 22b and the diaphragm 22a are formed as a single component. The diaphragm chamber wall member 30 clamps the diaphragm 22a in place, and thereby also locates and clamps in place the exhaust valve flap 22b such that they are physically side-by-side. The resultant close proximity between the exhaust valve and the diaphragm assures that slight pressure losses through the exhaust valve will not be sufficient to displace the diaphragm inward with a subsequent release of breathing gas. 
     During exhalation, the pressure in the chamber 18 exceeds that in the chamber 25. As a result, the exhaled gases cause the exhaust valve flap 22b to deflect outward, as to the position 22b shown in phantom in FIG. 2. The relatively large opening bounded by the edge 28 and 28&#39; enables unrestricted flow of the exhaled gases into the relatively large volume of the chamber 25 and subsequently out of the regulator 10 via the openings 24. 
     The wall member 30 isolates the chambers 25 and 31, and thereby isolates the diaphragm 22a from the turbulance generated by the exhaled gases as they flow through the chamber 25. As a result, operation of the diaphragm 22a is not affected by the flow of gas from the exhaust valve. 
     The exploded view of FIG. 5 shows a preferred embodiment of the invention which is configured for ease of manufacture and assembly. The main portion 17 of the housing is a unitary molding that includes the cylindrical section 17a and a portion 17b&#39; of the cylindrical housing that contains the inventive diaphragm and exhaust valve assembly. This cylindrical housing is completed by a rigid cap member 36, the cylindrical skirt 36a of which has an interior peripheral ledge that matingly engages a corresponding recess 23a on the cylindrical housing 17b&#39;. 
     The separating wall 37 is situated within the cylindrical housing 17b&#39;, and divides the interior of the housing 17 into an interior chamber 18 and an exterior zone encompassing the chambers 25 and 31. The separating wall 37 has two closely adjacent spaced openings therewithin. The first is a circular opening 37a which is covered by the inhalation sensing diaphragm 22a. The second is a generally semicircular exhaust opening 37b which is overlaid by the exhaust valve flap 22b.  Advantageously, the portion 28 of the separating wall 37 which surrounds the semicircular portion of the opening 37b is disposed at an angle with respect to the plane of the portion of the separating wall 37 surrounding the circular opening 37a. 
     A unitary diaphragm member 29, including the diaphragm 22a and the exhaust valve flap 22b, seats against the separating wall 37. The member 30 is held in place by a pair of screws 38 which pass through holes in the housing 17, holes 38a in the separating wall 37, holes 38b in the unitary diaphragm member 29, and threaded holes 38c in the diaphragm chamber wall member 30. A circular groove 30a captures the circular bead 22c surrounding the diaphragm 22a, thereby preventing slippage of the unitary diaphragm member 29 parallel to the surface of the separating wall 37. 
     The wall member 30 includes a conical portion 30d which is truncated by and communicates with a cylindrical section 30e. The conical portion 30d is dimensioned to provide room for unimpeded movement of the inhalation sensing diaphragm 22a. The interior of the conical portion 30d and the cylindrical portion 30e form the chamber 31 which communicates to the exterior of the second stage 10 via the holes 34 in the cover 32. Thus one side of the inhalation sensing diaphragm 22a is exposed to the inhalation pressure within the interior chamber 18, while the other side of the diaphragm 22a is exposed to ambient conditions, (e.g., the ambient water pressure). 
     The diaphragm chamber wall member 30 also defines the inner wall of the chamber 25 which communicates to the exterior of the regulator 10 via the openings 24. It is through this chamber 25 that exhaled gases are exhausted. 
     The planar peripheral portion 30c of the wall member 30 is truncated along a straight edge 30f which captures the proximal edge 22e of the exhaust valve flap 22b which lies along the bend line 37d of the separating wall 37. This arrangement permits the exhaust valve flap 22b to deflect away from the semicircular opening 37b (as shown in FIG. 2) to create an exhaust path for exhaled gases. 
     The use of the diaphragm chamber wall member 30 eliminates detrimental interaction between the flow of exhaled gases and the inhalation sensing diaphragm 22a. By utilizing separate chambers 25 and 31, the exhaled gases flow past the exhaust valve flap 22b, through the chamber 25 and the openings 24 to the exterior of the regulator 10, without adverse affect on the inhalation sensing diaphragm 22a which is separated from the exhaled gases by the wall member 30. Accordingly, an arrangement is achieved in which the exhaust valve is situated in close proximity to the inhalation sensing diaphragm, and yet is isolated therefrom. 
     For ease of assembly, the cap member 36 is held in place by the flexible cover 32, the cylindrical skirt 32a of which overlies the cylindrical portion 30e of the wall member 30. A peripheral flange at the end 30b of the wall member 30 is engaged by a corresponding groove 32b in the interior of the skirt 32a. 
     The cylindrical portion 30e of the wall member 30 projects through an opening 36c in the cap member 36. This opening 36c has a diameter just slightly larger than that of the skirt 32a so that the flexible cover 32 will be situated within the opening 36c when the skirt 32a is in engagement with the wall member end flange 30b. A flange 36b in the opening 36c engages the bottom of the skirt 32a, so that the cover 32 prevents separation of the cap member 36 from the housing 17. 
     The purge button 33 has a groove 33a that engages the central opening 32b in the flexible cover 32. When the purge button 33 is depressed, a projection 33b engages the plug 26 at the center of the diaphragm 22a and presses this plug against the lever 20, thereby opening the air inlet valve to purge the regulator.