Diving Helmet

Abstract

A diving helmet comprising a plastic or elastomeric hood having open cellular foam for conformance to a diver's lateral facial configuration, and connected to a rigid shell having a viewing port, the shell being connected to the hood by a split band circumscribing the shell overlying a flange of the hood, the band having a plurality of projections which cooperate with an elastomeric spider to maintain the helmet in secured relationship on a diver's head. The shell has an adjustable breathing gas demand regulator, and a second breathing gas source in the form of a valve that serves the function of introducing gas directly into the mask on a controlled basis, as well as providing for the introduction of emergency breathing gas into the helmet; the shell having a valve port for exhausting gases introduced in the foregoing manner, and any water residing in the shell.

Description

BACKGROUND OF THE INVENTION

The field of this invention lies in the art of diving helmets.

Activity in commercial underwater diving has increased dramatically within recent years. However, much of the apparatus relates to underwater life support has not kept pace with the increased activity and the attendant need for advanced diving equipment. This is particularly true where divers remain submerged for long periods of time to service drilling rigs another devices used for underwater exploration and mineral recovery.

Self contained breathing apparatus is insufficient and serves to encumber the activities of a commercial diver during extended periods of time under water. The instant invention provides a diver with a life support system which enables the diver to work effectively for long periods of time under water. Prior life support systems, particularly those portions comprising helmets and masks for usage under water during extended periods of time have not been serviceable, nor provided the diver with a safe and comfortable helmet. Such helmets and masks are usually fed by a source of breathing gas pressurized at the surface through a hose commonly referred to in the art as an umbilical. The umbilical is commonly fed by a compressor or pressurized tank of breathing gas at the surface.

One of the major drawbacks of prior art masks is the fact that when a decrease in pressure occurs in the umbilical, due to an interruption in the supply source, the loss can have dire consequences to a diver aside from the loss of breathing gas. Some masks are equipped with one-way valves to prevent this problem, but these valves are subject to failure. With the loss of source gas the remaining gain the mask and the umbilical tends to seek a less pressurized state and the mask has a vacuum condition created therein if there is no one way valve or it fails. This is due to the pressure at increased depths causing the gas at those depths to seek a lesser pressure at shallower depths or at the surface. The foregoing vacuum condition causes the prior art masks to collapse and draw into the diver's facial flesh creating a substantially irreversible seal and further increasing the vacuum condition. This condition is so severe that it will pop the eyeballs of the diver out of the sockets and draw his tongue into a contorted condition out of his mouth. Furthermore, there is often an attendant rupture of the blood vessels of the diver and the condition can greatly jeopardize a diver's life.

Prior art dividing helmets have not had a breathing gas demand regulator which is adjustable to provide for differentials in depth and breathing pressure changes. The instant invention overcomes this deficiency by providing an adjustable demand regulator which serves to effectively compensate for changes in depth pressure as well as the desired inhalation pressure forces of a particular diver.

Prior art masks do not incorporate a suitable hood configuration which helps to keep the diver's head warm and at the same time position the mask and communication earphones in a comfortable manner. The instant invention provides a hood in conjunction with the entire helmet which is easily placed on a diver's head and can be taken off rapidly should an emergency develop. The prior art masks merely had a series of strips which held a mask in place by pressing it against a diver's facial flesh. The instant invention has a unique spider that holds the helmet in place, and serves to comfortably position it in a balanced and serviceable manner.

The prior art did not incorporate a combination valve which acted as a manifold for feeding a demand regulator, as well as providing a steady flow of air into the mask and a fog or condensation eliminator when desired. The instant invention provides such a feature as well as an additional component which incorporates an attachment for connection to an emergency gas supply.

Prior masks usually have spaces which create undesirable quantities of CO.sub.2. The instant invention overcomes this by an oral-nasal cover which reduces the dead space in the diver's mask, as well as incorporating a pressure equalizing means therethrough.

SUMMARY OF THE INVENTION

This invention provides a commercial diving helmet which will not physically jeopardize a diver when the source of breathing gas is terminated from the helmet. The helmet also incorporates features related to the introduction of the breathing gas supply and overall operation which in combination enable a diver to function more effectively.

The invention partially resides in a stiffened or substantially non-deformable shell which will not collapse upon evacuation of the gas from the helmet when the helmet is under water. The shell in conjunction with the hood and face seal functions to provide a safe and comfortable helmet which will not injure a diver upon gas evacuation as is the case with prior helmets, and masks. The rigid shell holds the face seal in a manner such that the mask will flood with water rather than subject the face to a substantial lowering of pressure.

The means for securing the helmet to a diver's head incorporates an elastomeric spider having a plurality of arms which are secured to a plurality of projections on a circumferential portion of the main body of the helmet. Such securement is performed simply and enhances mobility of the diver to improve the entire functional characteristics of the helmet.

The helmet incorporates a nasal pressure equalization device, and an adjustable demand regulator. The adjustable demand regulator compensates for changes in depths as well as respective inhalation pressure forces which a diver finds most comfortable for breathing purposes.

The invention incorporates a combination valve and manifold which introduces a steady stream of breathing gas into the helmet when desired. The manifold permits a bypass of the steady stream delivery means so that a demand regulator can be utilized under normal operation. The combination manifold and valve also enables an emergency gas supply to be introduced to the mask by means of a second inlet port incorporated therein.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of the helmet of this invention in use;

FIG. 2 shows one of the securing means of this invention for holding the helmet on the head of a diver;

FIG. 3 shows a cross section of the sealing means of the helmet along line 3--3; and

FIG. 4 shows an exploded vie of the major portions of the helmet.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Looking at FIG. 1, a perspective view of the helmet is shown in use on a diver. A portion of the surrounding environment is incorporated to facilitate ease of understanding with respect to how the helmet is used when secured to a diver.

A diver is shown having a wetsuit 10 which maintains a diver's warmth and comfort during diving operations. A helmet 11 incorporating this invention is shown which serves to provide the diver with a major portion of this life support system. Attached to the diver's back is a supply tank 12 filled with breathing gas. The supply tank 12 is harnessed to the diver by means of harness straps 14 connected to a carrying pack 16 in which the tank is placed. The tank 12 has a valve assembly comprising a tank valve 18 secured to the tank by means of a tank outlet 20. The tank valve has a nipple 22 extending therefrom, which is attached to a first stage regulator 24, which is commonly used for regulating pressurized gas for underwater breathing purposes. A hose 26 is connected to the first stage regulator 24 at one end and to a side valve to be described. The hose 26 facilitates the supply of breathing gas for use when a breathing gas source at the surface is not utilized, or when an emergency arises due to a termination of the surface supply.

The helmet 11 incorporates a hood portion 32, and a rigid shell portion 34. The shell and the hood 32 are jointed by overlying flange 36 of the hood 32 which seats over a slightly flared portion 38 of the shell. The hood flange 36 which seats over the flared circumferential portion 38 of the shell is secured by semi-circumferential bands 40. The semi-circumferential bands have projecting securing blocks 42 at either end thereof. The securing blocks 42 are aligned in juxtaposition when the bands 40 are in place and have respective holes 44 therein aligned for mutual securement. The holes 44 of each band are axially oriented over holes of the opposite securing block 42 of the semi-circumferential band portion 40. The aligned holes 44 have a rivet or bolt passed therethrough as generally shown at 45. The bolt 45 is secured by a nut at one end, or a flattening of a rivet if a rivet is used. Regardless of which is used, the semi-circumferential bands 40 should be maintained in snug relationship to prevent leaking between the seal provided by the flange 36 and the flared portion 38 of the shell 34.

A face plate 48 is provided which may be made of any suitable material, but is preferably made from acrylic plastic. The face plate 48 fits into a molded recess 50 of the shell 34. The molded recess is provided with vulcanizing rubber to seal the face plate 48 therein. A retainer 52 made of metal is placed over the face plate 48. The retainer 52 is secured to the shell 34 by means of screws 54 which are threaded into holes 56 thereof. In this manner, the face plate 48 is secured into the recess 50 not only by the vulcanizing rubber, but also the retainer 52 which serves to tightly secure the face plate.

Passing through the retainer into the shell is a pressure equalizing device 55 for blocking the nostrils of a diver. The pressure equalizing device 55 comprises a rod 56 which extends through the retainer 52 into the interior of the helmet 11. At one end of the rod is a ball 58, and at the other end adjacent the nostrils of a user is a pad 60 which is pushed against a diver's nose allowing him to blow thereagainst for equalizing the pressure within the sinus and inner ears during underwater descent. The rod 56 is maintained in the retainer 52 by sealing nuts 62 and O-rings not visible in the drawing, which prevent leaks at the point where the rod passes through the retainer 52 into the shell through a hole 64.

The hood 32 is made of a wetsuit type of material 65 such as a closed cell neoprene or other elastomer. Inside the hood 32 is an open cell foam 66 which is adhered into a skin or sealing elastomer 67 similar to that material 65 of the hood 32. The sealing elastomer or skin 67 is formed in such a manner as to be placed in juxtaposition to a diver's facial configuration when the helmet 11 is on. Thus, on the diver's side of the open cell foam a thin layer or skin of closed cell foam rubber 67 or solid rubber sheet is glued. The open cell foam 66 forms a comfortable cushion and the skin 67 provides a sealing surface against the diver's face. The open cell foam 66 as will be described, is necessary to prevent collapse under increased pressure. It should be noted that the open cell foam 66 is interior of the flange 36 of the helmet 32, which fits over the shell 34 so that the foam is in effect interior to the inner circumferential portion of the shell. The fact that the open cell cushion 66 and skin 67 which forms a seal is interior to the circumference of the shell at the point where it forms a seal with the diver's face is significant. The placement serves to provide movement of the foam between the shell 34 and the diver's face without substantial inward movement from the shell 34 to the face of a diver. This placement prevents an inward collapsing and sucking action which produced the intolerable vacuum of the prior art helmets, when the umbilical is cut, or a similar cutoff of the breathing gas occurs.

The hood 32 incorporates a pair of pockets 68 which are in juxtaposition to a diver's ears when in use. The pockets 68 open to the interior of the main body of the hood and receive a pair of head phones 70 which are connected by cables 72 to an appropriate terminal in the helmet. A microphone 74 is also provided to enable two way communication with the surface.

In order to reduce the dead air space within the helmet, an oral-nasal mask 76 is utilized. The oral-nasal mask 76 fits over the nose and mouth of a diver and permits the incoming breathing gas through hole 77 to flow steadily thereinto and then out through the regulator exhaust to be described.

A demand regulator 80 is shown in a partially exploded view. The demand regulator fits into an opening 82 within the lower portion of the shell 34 and is bolted thereto through holes 83 provided in the shell. The demand regulator is adjustable to provide a variable source of breathing gas to the interior of the helmet through holes 82 and 77 in accordance with ambient pressure, inhalation forces and overall compatibility with the specific diver. The demand regulator 80 is supplied with gas from the hose 84 which is connected to a valve source to be described. On one side of the demand regulator is a nipple and combination valve seat 86 threaded into an internal thread of the regulator 80. The gas entering the nipple is checked by an inlet valve piston 88. A diaphragm 90 is provided which fits into the regulator body. When a diver inhales he draws the diaphragm against ta spacer 91 contacting a lever 92 which pushes the inlet valve piston 88 away from its valve seat allowing gas to flow through the hose 84 into the interior of the helmet 11.

The adjustability of the demand regulator is provided by the following mechanism. The valve piston 88 has a stem 95 within the interior of the regulator 80. The valve piston 88 is urged against its seat by means of a spring 96 and spring piston 97 which attendantly biases the valve piston and holds back the incoming gas until the lever 92 is activated by internal flexing movement of the diaphragm 90. A threaded adjustment shaft 98 is utilized to change the spring compression by rotation which moves the shaft 98 longitudinally against the spacing piston 97 to compress the spring and attendantly adjust the pressure required for valve actuation. The threaded adjustment shaft is secured to the regulator by means of a nut 100 and is controlled by a nurled knob 102 threaded onto the shaft 98. Thus, the diver can naturally change the spring compression to provide for a wide range of incoming pressures or ambient depths compatible with the diver's inhalation forces. As is customary with most demand regulators, an outlet port 104 is provided.

In addition to the foregoing diaphragm action caused by the diver's inhalation, the demand regulator may be operated by means of depressing a smaller elastomeric diaphragm 106 on the covering plate 108 of the regulator. In this manner, the delivery of gases into the helmet is facilitated for purging any water which lies in the base of the shell 34.

Breathing gas is delivered to the helmet under the majority of operating conditions by means of a hose commonly referred to as an umbilical 110. The umbilical is connected to a one way valve 112 passing into a dual combination valve and bypass manifold 114. The one way valve 112 allows air to flow inwardly into the dual combination valve and bypass manifold 114 but not back out. At one end of the valve and bypass 114 is an inlet nipple and one way valve 116, into said valve and bypass, connecting the hose 26 to the breathing gas supply tank 12. Attached to the other end of the valve and bypass manifold is an outlet nipple 118 having the hose 84 connected to it for purposes of providing the demand regulator 80 with a source of breathing gas. The combination valve and bypass manifold 114 is equipped with a shut-off valve interiorly thereof for purposes of cutting off gas flow through a pipe 119 connected to the bypass valve. The pipe 119 leads into the shell through a hole 120 for delivering breathing gas thereinto. The bypass valve is controlled for on and off flow of gas through the pipe 119 by a serrated knob 121.

The bypass manifold and valve 114 is attached to the shell 34 of the helmet by means of a bolt 122 which passes through a hole 124 in the side of the shell and is suitably secured by a nut turned down thereon.

The pipe 119 leading into the helmet through the hole 120 connects directly into a muffler and distribution system. The muffler and distribution system is generally comprised of a cellular foam material or lamb's wool, not visible, which is held in place by a perforated grate 128. Thus, as the gas is introduced into the helmet, it is muffled to prevent its spreading as a direct blast of gas. The perforations of the grate 128 are directed so that they displace the gas in the direction of the interior portion of the face plate 48 so that a clear and fogless faceplate can be maintained. The knob 121 permits the diver to occasionally operate the valve so that any fog on the face mask may be eliminated by a blast of gas. The flow of gas through the pipe 119 is also utilized for clearing the helmet of any water in the base thereof.

At the base of the shell 34 is a flapper exhaust valve 130. The exhaust valve 130 comprises a disc 132 which is seated in the base of the helmet with a flapper membrane 134 emplaced therein, and covered by a cover 135. The disc 132 has an opening 133 that is spanned by a web 137 which serves to partially support the membrane 134. When a positive pressure is exerted against the internal side of the flapper membrane 134, the membrane is released and permits any gas or entrapped water at the base of the helmet to flow outwardly into the surrounding environment.

Attached to the semi-circular bands 40 are a plurality of projections 138 with balls 140 at their ends. The projections 138 with the balls 140 serve to hold the mask in place in conjunction with an elastomeric spider 142. One embodiment of the elastomeric spider has a series of holes 144 placed within five projecting legs 146 of the spider. The spider is placed over a diver's head with the base joindure thereof at the back of a diver's head. The legs 146 are pulled forward tautly so that the holes of the spider 144 can be pulled down over the projecting balls 140 to allow the spider to secure the helmet on the head of a diver. The plurality of holes 144 permit adjustment of the tension of the legs 146 so that a diver may adjust the entire spider to the most desirable degree of tautness and comfort.

In addition to the foregoing embodiment, a spider 142 having adjustable metal loops on the legs 146 may be utilized. The loops are interlaced with the ends of the spider legs in the manner shown so as to facilitate adjustment of the length of the legs. Once the loops have been adjusted to provide a specific length of spider leg 146 and tension for an individual diver, there need be little further adjustment thereof.

In operation, the helmet is placed over, a diver's head with the air supply turned off. The nasal pressure equalizing device 55 with the pad 60 at the end thereof is pulled out so that it does not interfere with the placement of the helmet over the diver's head. When the helmet is placed properly over the diver's head a slight inhalation will create a suction on the face seal provided by the skin 67 indicating a good seal. Further inhalation by the diver will cause the seal provided by the open cell foam 66 and skin 67 to leak slightly around the diver's face. This is caused by the skin 67 seal being broken when a substantial degree of suction is encountered due to the rigidity of the shell 34 in combination with the open cell foam 66. The stiff shell 34 permits a placement of a seal, namely the open cell foam 66 and skin 67 in a manner such that a suction will not draw it constantly against the facial configuration of the diver as the pressure increases. Instead, the seal can only move inwardly a certain distance toward the facial configuration of the diver, thereby preventing a complete seal thereagainst, and the undesirable vacuum attendant with prior art masks.

The umbilical 110 or self contained gas supply in the tank 12 depending upon which is used respectively, is delivered normally to the demand regulator 80. If the valve of the combination valve and manifold 114 is turned on, the gas is delivered through the muffler system grate 128. During normal operation, the demand regulator 80 should be adjusted by the hurled adjusting, handle 102, so that a slight steady flow is provided.

The joindure of the spider 142 should be as low on the neck as possible so that a pressure is put on the base of the skull by the lower two legs 146 thereof. The amount of tension to be put on the spider 142 will vary from diver to diver and can only be determined by the specific cranium configurations of each respective diver using the helmet 11.

The diver is now ready to enter the water and use the helmet for underwater operations. It may be necessary to readjust the demand regulator 80 by means of the nurled handle 102 during descent. A very slightly steady flow is the most desirable adjustment, however, the adjustment of the demand regulator 80 should compensate for the different pressures which a diver encounters during descent.

In the event of a partial or complete flooding of the helmet, the valve of the valve and bypass manifold 114 which delivers gas through the muffler grate 128 may be actuated by the knob 121. The actuation of the handle 121 will cause gas to be delivered through the muffler grate 128 and purge any water through the flapper valve 130 at the base of the helmet 11.

In lieu of purging water by introducing gas under pressure through the muffler grate 128, a pressing of the small diaphragm 106 of the demand regulator may be utilized. Upon pressing the diaphragm 106 the lever 92 will be actuated causing gas to stream into the helmet and create a positive pressure thereby purging water in the base of the helmet through the flapper valve 134.

Should the supply of gas from the umbilical become limited or cut off by source inoperativeness, or a rupture in the line, the increased pressure at the depth of the helmet will cause the air in the helmet to vent through the umbilical. This causes a decreased pressure within the helmet as compared to the ambient water pressure, so that the sealing skin 67 has a tendency to draw inwardly to the facial configuration of the diver. However, inasmuch as the stiffened shell of the helmet 34 does not tend to collapse, the open cell foam 66 and skin 67 can only draw in a certain amount toward the facial configuration of the diver. The foregoing causes the water to flow into the helmet partially or substantially flooding it. This prevents the vacuum pressure from building up within the helmet to an intolerable amount as in the prior art helmets and masks which caused eyeball loss and serious injury to a diver. In other words, the seal is designed to open before the pressure inside the helmet falls low enough to result in a dangerous squeeze on a diver's face.

If the diver reacts quickly enough to the loss of gas pressure through the umbilical 110, he may utilize the emergency gas source in the tank 12 delivered through the hose 26. This is effectively done by turning the valve assembly 24 of the regulator on the gas supply tank into the on-position. In this manner the diver can effectively prevent a substantial flooding of the helmet and of course, any deleterious effects normally caused by facial squeezing due to depressurization in the helmet.

Only one form of the invention has been shown and described. However, it should be understood that the invention is not limited to the foregoing description alone. Various changes may be made in the invention by means of equivalents. For example, various types of configuration may be utilized in the size and shape of the helmet without departing from the spirit of the invention. Therefore, the limits of the invention shall be defined only by the following claims.

Claims

I claim:

1. A diving helmet for use with a source of breathing gas connected thereto comprising:

a substantially stiff shell forming a cavity for the receipt of breathing gas under pressure and having a major opening through which a portion of a diver's facial configuration can extend and adapted to form a constant space between a user's face and the interior surface of the major opening of said shell in at least one portion thereof;

a port in said shell proximate to where a diver's field of vision is obtained;

a transparent face plate sealing said port from water passage into said shell;

means for introducing breathing gas into said shell;

a resilient deformable seating means attached to said shell and placed at least in part around the inner periphery of said cavity proximate to said major opening through which a diver's face extends providing in the space between a user's face and the interior surface of the majority opening a seal when there are no substantial pressure differentials between the interior of said shell and ambient water pressure so that upon a decrease in pressure of substantial nature within said shell with respect to ambient pressure, said seal will permit ambient water to pass into said shell by deforming into said shell; and,

means to secure the helmet to a diver's face.

2. The helmet as claimed in claim 1 wherein:

said resilient deformable sealing material comprises a foam elastomer.

3. The helmet as claimed in claim 1 wherein said means for introducing a breathing gas to said helmet at least in part comprises;

an adjustable valve with an inlet port and connected to said shell through an outlet port thereof for introducing breathing gas across the face plate thereof to provide a source of breathing gas to said helmet as well as removing fog and condensation from the interior portion of said face plate.

4. The helmet is claimed in claim 1 further comprising:

a demand regulator connected to said shell for introduction of breathing gas from a source of such gas wherein said demand regulator is adjustable to provide gas upon inhalation by a user under different inhalation and ambient pressures;

an adjustable valve with an inlet port connected to said shell through a first outlet port thereof for introducing breathing gas under pressure; and,

a bypass manifold in said adjustable valve to a second outlet port for connection through said demand regulator so that when the adjustable valve is not passing gas through said shell through said first inlet port, it can deliver gas to said demand regulator.

5. The helmet as claimed in claim 4 wherein:

said valve further comprises a second inlet port extrinsic to said first inlet port, said first inlet port incorporating a one way valve thereinto so that a first and second source of breathing gas under pressure can be delivered to said valve and bypass for release respectively through said outlet ports.

6. The helmet as claimed in claim 1 wherein said means for securing said shell to a diver's face comprising:

a plurality of elastomeric arms extending from a common joindure, said common joindure being at the back of a diver's head when said helmet is in use;

a plurality of projections placed around at least a portion of the outer port of said shell for connecting said arms thereto; and

means on said arms for connecting them to said projections.

7. The securing means as claimed in claim 6 wherein said means comprise:

projections extending from the circumferential periphery of said shell in the form of appendages ending to enlarged rounded portions;

openings within said arms for placing over the rounded portion of said appendages.

8. The securing means as claimed in claim 6 further comprising:

a loop attached to said arms for placing over said projections.

9. The helmet as claimed in claim 1 wherein:

said hood is joined to said shell by a band circumscribing said shell with a portion of said hood lying between said circumscribing band and said shell in tight relationship therewith to provide securement of the hood with said shell.

10. The helmet as claimed in claim 9 wherein:

a hood is joined to the shell of said helmet;

said band is split and connected by protuberances in overlying juxtaposed relationship with a fastener holding the protuberances of each band in connected relationship.

11. An underwater diving helmet comprising:

a demand regulator;

a relatively stiff shell forming a cavity for the receipt of breathing gas under pressure from said demand regulator having a major opening defining edge regions adapted to be constantly at least partially in spaced relationship from a user's face with a seal means comprised of a resilient deformable material in proximity to said opening thereof for placement against the facial configuration of a diver;

a port in said shell proximate to where a diver's field of vision is obtained;

a transparent face plate sealed into said port;

an inner mask for covering at least a portion of a diver's mouth and connected to the demand regulator for delivery of breathing gas to the mouth of a diver;

means to secure said diving helmet over a diver's head for placing the seal means in proximity to a diver's face so that upon a decrease in pressure within said relatively stiff shell with respect to ambient water pressure said resilient material will deform inwardly and allow water to pass into said shell.

12. The helmet as claimed in claim 11 further comprising:

means for moving a closure over the nose of a user from the outside of said shell.

13. The helmet as claimed in claim 12 wherein said closure means comprises:

an axially moving member for movement within an opening of said shell;

sealing means for substantially preventing water from entering the interior of said rigid body where said axially moving member passes therethrough; and

a resilient body for covering the nasal openings of a diver when said axially moving member is moved inwardly toward the nose of a diver.

14. The helmet as claimed in claim 11 further comprising: a hood which is joined to the shell of said helmet.

15. The helmet as claimed in claim 11 wherein said means for introducing breathing gas under pressure comprises:

a valve with an inlet port for receiving breathing gas;

an outlet port in said valve connected to said shell for the passage of gas into said shell therefrom;

a second outlet port within the body of said valve for connection to said demand regulator.

16. The helmet as claimed in claim 15 further comprising:

an exhaust valve in said shell for causing overpressures and exhaled air to be emitted therethrough.

17. A diving helmet comprising:

a stiff shell having a cavity for the receipt of breathing gas and a major opening for a diver's face, said shell having edge portions which define regions adapted to be constantly in spaced relationship from a user's face;

a demand regulator adapted to be connected to a source of breathing gas;

an inner mask in said shell for covering at least a portion of a diver's mouth which is connected to said demand regulator for delivery of breathing gas from said demand regulator into said inner mask;

a manifold valve with a first and second outlet, with said first outlet connected through said shell, and said second outlet through said demand regulator into said inner mask;

elastomeric means for securing said helmet to the face of a diver;

and, a resilient deformable seam means attached to the opening of said shell for providing a seal when there are no substantial pressure differentials between the interior of said shell and ambient water pressure so that upon a decrease in pressure of a substantial nature within said shell with respect to ambient pressure, said seal will permit ambient water to pass into said shell by deforming into said shell.