US3048140A - Underwater propulsion device - Google Patents

Description

Aug. 7, 1962 E. R. DAVIS, SR

UNDERWATER PROPULSION DEVICE Filed June 22, 1960 FIG. 5

R .S m 3 MW A MD w. R E N E G U E BY mum JENNEY, WITTER & mumsm FIG. 4

ATTORNEYS United States Patent Ofiiice 3,048,140 Patented Aug. 7, 1962 3,048,140 UNDERWATER PROPULSION DEVICE Eugene R. Davis, Sn, Jay, N.Y., assignor t Newell N. Davis, Marblehead, Mass. Filed June 22, 1960, Ser. No. 37,923 Claims. (Cl. 115-61) physical efforts. Although certain underwater propelling means are presently available, they have not proven entirely satisfactory for one reason or another. Battery operated underwater vehicles, for instance, are heavy and relatively expensive to build and depend upon rotation of a conventional propeller which may prove dangerous to the diver. Various other contrivances have been proposed from time to time but, because of mechanical complexities in efiiciency or other reasons, have not met with wide acceptance.

It is an object of the present invention to provide a portable and compact underwater fluid operated engine that is adapted to attach to and propel a diver safely through the water.

Another object of this invention is to provide a lightweight and inexpensive underwater propelling machine having no major moving parts.

Yet, another object of this invention is to provide an extremely simple underwater engine which may use as a source of energy either compressed air from conventional underwater breathing equipment or the divers own exhaust.

More particularly, this engine features an underwater ram jet engine adapted to be strapped or otherwise mounted on the back of a skin diver. The engine, if

given an initial forward thrust, is operated by injecting gas under pressure into the engine duct at a point where the static pressure of the water flowing through the duct is greatest. The injection gas may be supplied by a tank of compressed air forming part of the divers underwater breathing apparatus. This source may be supplemented by the divers own exhaust if desired.

These and other features of the invention together with further objects and advantages thereof will become apparent from the following detailed description with reference being made to the accompanying drawings in which:

FIG. 1 is a view in side elevation, partly in section of a swimmer fitted with an underwater ra-m jet engine made according to this invention,

FIG. 2 is a sectional view in side elevation of the engine duct shown in FIG. 1 but on an enlarged scale,

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2,

FIG. 4 is .a cross-sectional view of an engine duct having a modified contour, and

FIG. 5 is a modification of the engine in which an underwater ram jet engine is used to drive an underwater sled.

Referring now to FIGS. 1 and 2, the reference character generally indicates an underwater ram jet engine comprising a duct 12 having an axial fluid passageway 14 formed therein. The duct preferably should be fabricated from a lightweight and noncorrosive material such as plastic or aluminum in the form of a pair of oppositely directed, truncated hollow cones joined at their bases. A gas injection station is located approximately mid-way along the duct where the passageway is widest. This station includes a compressed air injection nozzle and an outlet 22 for introducing the divers exhaust into the fluid passageway. v p

The engine, as shown in FIG. 1, is mounted on the back of a diver in connection with a conventional underwater breathingoutfit or an aqualung. The assembly shown includes one or more cylinders 24 of compressed air suitably fastened to the diver by meansof a harness 26. A pair of braces 28 engaging the cylinders 24 serve to support the engine 10 rigidly thereto. When properly mounted, the engine will be arranged with its inlet port 16 positioned forwardly or near the divers head with I an exhaust port 13 located to the rear so that the engine will be generally parallel with respect to the divers length and serve to propel the diver in a head-first manner. A short section of pipe 30 extends from the cylinder and is provided with a branch conduit 32 leading to the injection nozzle 2i) through a pressure regulating valve 34-. For ease of control, the valve 34 may be provided with a remote control arrangement comprising a flexible extension stem 36 having an adjustment handle 38 attached to the fixed buckle on the divers harness. Another pressure regulating valve 40 is connected to the pipe 30 beyond the conduit 32 and controls the flow of air through a flexible tubing 42 to the divers mouth piece. Another flexible tubing 44 also connected to the mouth piece extends rearwardly to the outlet 22 and directs the .divers exhaled air into the fluid passageway 14.

Once submerged in the water with the engine and associated equipment attached, the diver may start the engine by giving it an initial forward velocity. This may be done by swimming, towing or any other suitable means. With water flowing through the duct, the valve 34 may be opened to inject pressurized air into the fluid passageway. high but, once the engine is operating normally and under its own power, the air may be throttled down to whatever speed is desired. It is, of course, necessary that the injection pressure at all times be at least slightly higher than the static pressure of the water.

The water entering the duct through the inlet port has a portion of its velocity energy converted into static pressure or ram as it flows to the gas injection section of the duct. Gas is injected as desired into the water within the fluid passageway at a point where the static pressure of the water is at a maximum. The water within the duct then has this maximum static pressure converted back into velocity energy as it travels to the gas injection section to the exhaust port. The gas, which is introduced into the water stream at the highest static water pressure section of the duct, is carried in the form of dispersed bubbles and water foam with the water stream to the exhaust port. A combination of water, gas bubbles, and foam is consequently ejected from the exhaust port. The gas bubbles introduced at the point of high static pressure expand as they are carried by the water stream toward the exhaust port due to the decrease in static water pressure as the water pressure is converted into velocity energy. The effective exhaust port area is thus reduced, effectively increasing the velocity energy of the water as it emerges from the duct outlet relative to the velocity energy of the duct intake.

The power output of the engine is controllable in accordance with the relationship established between the duct configuration, the water velocity entering the duct, the quantity and pressure of gas injected into the duct, the static water pressure in and around the duct, the

Initially the injection pressure should be rather.

temperature of the gas, and the velocity of the duct relative to the water.

Normally, the engine duct is circular in cross section as shown in FIG. 3 but, for some installations, it may be desirable for the duct to be crescent shaped in cross section as suggested by FIG. 4. Other configurations may be employed to facilitate packaging or attaching the engine to the divers air tank. The design of the ducts for non-circular cross sections will be such that essentially the same conversion of water velocity energy to static pressure and the reconversion of static pressure back into water velocity energy will be maintained as when using the duct circular cross section.

In FIG. 5, there is shown a modification of the engine. In this embodiment, an engine 10 similar to that of FIGS. 1 .and 2 is rigidly suspended from a transparent dome 46 by a strut 48. The dome is rather streamlined and serves to reduce the dynamic drag of the diver and his equipment. Several equalizing ports 50 near the bow of the dome and a pair of arm straps 52 may be .attached to the lower inner surface of the dome.

As in the first embodiment, the engine is powered by compressed air from the divers breathing tank through a line 52 passing through the dome and the strut 48 into the engine duct at the point of maximum static pressure. The valve 34 controls the flow of air to the line 32' and conveniently may be provided with a remote control flexible cable 56 extending forwardly to the bow of the dome where it may be readily manipulated by the diver. It will be obvious that an-exhalation line, similar to that of FIGS. 1 and 2, may be provided in the FIG. 5 device to utilize the divers exhaust breath.

Those skilled in the art will readily appreciate that numerous modifications of the illustrated embodiments may be made withoutdeparting from the spirit of my invention, therefore it is not intended that the scope of my invention be limited to those embodiments illustrated and described but, that its breadth be determined by the appended claims and their equivalents.

Having thus described my invention, what I claim is new and desire to obtain by Letters Patent of the United States is:

1. An underwater propulsion apparatus for skin divers, comprising a tubular engine having an elongated body provided with a forwardly positioned inlet and a rearwardly positioned outlet of generally equal size, a passage in the body of said engine and connecting with said inlet and said outlet, the mid-portion of said passage being larger in cross section thansaid inlet and said outlet, the widest portion of said passage constituting a duct station corresponding to the maximum static water pressure within the duct when said engine is propelled forwardly under water pressure within the duct, conduit means for injecting air into said engine at said duct station, means for mounting said engine on a diver, underwater breathing apparatus including a portable tank of compressed .air adapted to be secured to a diver, a conduit from said tank to said duct station, and means for controlling the flow of air to said station.

2. An underwater propulsion device in combination with an underwater breathing apparatus for skin divers, comprising a tubular engine housing having a fluid passageway extending from one endthereof to the other, said passageway being greater in cross-sectional area at its mid-portion than at the inlet and outlet thereof, an air injection station located at the widest portion of said passageway, a compressed air tank associated with said underwater breathing apparatus, a conduit connecting said station with said air tank, and control means for regulating the flow of air to said station from said tank.

3. An underwater propulsion device according to claim 2 wherein said engine is provided with a conduit connecting said station to the divers mouth to direct the divers exhaled air to said station.

4. An underwater propulsion devcie according to claim 2, in which said control means comprises a valve having an elongated flexible control stem, and an adjustment handle drivingly connected with said stem and adapted to be mounted in an accessible position upon a diving harness for manual adjustment by a diver.

5. A combination underwater breathing and propulsion device for skin divers, comprising a compressed air tank, a tubular engine housing having an inlet, an outlet, and a fluid passageway extending therebetween, means mounting said housing on said tank, said passageway having a greater cross-sectional area at its mid-portion than at the inlet and outlet thereof, a branched conduit including a breathing tube portion for supplying air to a diver and a conduit connected to the mid-portion of said passageway, and control means for independently regulating the flows of air to said breathing tube and to said passageway from said tank.

Varney Oct. {24, 1950 Goodman Dec. 7, 1954

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