US3792580A

US3792580A - Portable underwater fuel feed system

Info

Publication number: US3792580A
Application number: US00213573A
Authority: US
Inventors: R Geres
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1971-12-29
Filing date: 1971-12-29
Publication date: 1974-02-19
Anticipated expiration: 1991-02-19

Abstract

A portable underwater hydrazine feed system for feeding hydrazine to a hydrazine decomposition reactor. The gas from the reactor may be used to drive a power tool, a swimmer propulsion device or the like with the exhaust gas from the driven device being employed to drive a gas operated differential area piston pump. The gas operated pump forces water into a chamber containing hydrazine. The hydrazine is isolated from the water by a slidable piston or expandable bellows and is displaced into the hydrazine decomposition reactor by the water.

Description

United States Patent 1 Geres PORTABLE UNDERWATER FUEL FEED SYSTEM [75] Inventor: Robert J. Geres, China Lake, Calif.

[73] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

[22] Filed: Dec. 29, 19711 [21] Appl. No.: 213,573

[52] U.S. Cl ..60/643, 222/389 [51] Int. Cl C0611 5/04 [58] Field of Search 60/51, 39.48, 259, 37, 36,

[56] References Cited UNITED STATES PATENTS 3,101,592 8/1963 Robertson et al. 60/37 3,436,914 4/1969 Rosfelder 3,525,217 8/1970 DeMattia et al 60/37 [451 Feb. 19, 1974 3,667,216 5/1972 DeMattia 60/37 Primary Examiner-Edgar W. Geoghegan Assistant Examiner-H. Burks, Sr.

Attorney, Agent, or FirmR. S. Sciascia; Roy Miller; R. F. Beers [57] ABSTRACT A portable underwater hydrazine feed system for feeding hydrazine to a hydrazine decomposition reactor. The gas from the reactor may be used to drive a power tool, a swimmer propulsion device or the like with the exhaust gas from the driven device being employed to drive a gas operated differential area piston pump. The gas operated pump forces water into a chamber containing hydrazine. The hydrazine is isolated from the water by a slidable piston or expandable bellows and is displaced into the hydrazine decomposition reactor by the water.

5 Claims, 4 Drawing Figures PATENTEDFEBIBIQH 3792 580 SHEET 3 [1F 3 FIG. 4.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pertains to portable underwater hydrazine feed systems for feeding a-hydrazine decomposition reactor. I

2. Description of the Prior Art Gas generators have been used extensively in missile systems for generating electrical power, providing gas for actuation of aerodynamic control surfaces, and providing high-pressure gas for expulsion of fluids in liquid propulsion and thrust vector control (TVC) systems. Other gas generator applications include auxiliary power supplies for aircraft, torpedo propulsion, balloon inflation, buoyancy systems, and cartridge actuated devices.

Solid propellants, liquid bipropellants, liquid monopropellants, hybrid propellants and the reaction of metallic hydrides and certain active metals with water have all been considered for various gas generator applications. While the characteristics of these systems vary considerably, they are in general very attractive on an energy density basis (in many cases exceeding even the most exotic battery systems). However, specific energy or power parameters are very sensitive to systemefficiency and the fuel mass ratio. Systems engineering is therefore particularly critical for gas generator power systems.

With development of the Shell 405 spontaneous catalyst for hydrazine, a new family of MGGs with demand restart capability, tailored exhaust gas temperature, and clean gas products isavailable. Hydrazine decomposes on the catalyst in the gas generator to produce an exhaust gas consisting of hydrogen, nitrogen, and ammonia. The prepackaged demand gas generator power system of the present invention offers significant advantages over present systems such as high specific power input, low maintenance, long term storage, simplicity of operation, portability, low noise, high fuel-tomass fraction, complete demand operation, and operation over a wide range of environmental conditions through neutral buoyancy through fuel depletion and depth insensitive fuel pressure differential. This unique combination of features presents significant improvements over existing applications of batteries, compressed gas, and small internal combustion engines.

Fo r'example, some systems today use direct gas pressurization i.e., the liquid hydrazine is displaced by gas from a source such as a bottle of nitrogen. As the liquid hydrazine is displaced by a gas it is seen that the buoyancy of the entire device increases. When such a device is being used by a diver to operate a tool, for example, the increased buoyancy would cause the diver to rise to the surface. Therefore, the need for neutral buoyancy is clearly seen.

Other prior art devices while maintaining a neutral I buoyancy, employ a spring expulsion system. A coil springis employed to move a piston in a cylinder causing displacement of the liquid hydrazine. Such a system does not provide a constant pressure differential between the hydrazine container and its point of destination. This is because the spring force decreases as the I spring elongates. Alsodue to the weight of the spring and piston, a poor fuel to mass fraction is presented i.e., the spring and piston constitute too great a portion of the mass.

Elastomeric bags have also been used for hydrazine displacement, however, they too do not present a constant pressure differential.

Another disadvantage of direct gas pressurization as with a bottle of nitrogen is that such a system does not have a depth insensitive fuel-pressure differential. For

example, the present device requires approximately v psi fuel pressure differential. To operate such a device below water at 1 1,000 psi ambient pressure for example would require bottled nitrogen at 1 1,150 psi. At

this pressure the size of the tank to hold the gas would be unweildable. The present invention, on the other hand, requires a pump capable of pumping a displacement liquid such as sea water at only 150 psi over ambient pressure.

The low noise characteristics of the present invention are especially desirable in underwater operations due to the high conductivity of noise underwater. This is especially true if the present invention were to be employed for operating a relatively noisy tool.

The most important features of the present invention, however, are its long term storage, low maintenance, and simplicity of operationthus leading to low production cost per unit. I I

SUMMARY OF THE INVENTION The present invention is a portable underwater hydrazine feed system for feeding liquid hydrazine to a demand hydrazine decomposition reactor. The present invention employs a boot strap operation in which a gas operated pump forces surrounding water into a, chamber causing displacement of a piston or compres sion of a bellows or flexible bag. The piston, bellows or flexible bag are employed to isolate the hydrazine from the water. As water enters the chamber the hydrazine is forced into a hydrazine gas generator. The gas from the generator is employed to drive a gas driven tool with the exhaust from the tool being employed to drive the gas driven water pump.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. is a schematic of the boot strap operation of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the invention enclosed bya steel cylindrical pressure vesselll with a hydrazine chamber 12 and water chamber 13 separated by piston 14. Rubber o-rings l6 and 17 serve to seal the water chamber from the hydrazine chamber.

The hydrazine is expelled into a hydrazine decomposition reactor 19 by displacing it with water which is pumped into pressure vessel 11 by gas operated differential area piston pump 18. Ambient water enters the pump through water inlet 21 and passes through pump 18 into water cavity 13 through passageway 22. Gas for driving the pump enters through gas inlet 23 which is connected to the exhaust24 of a gas driven motor 43.

Movement of pump 18 is initiated by the manual actuation of lever 26.

Hydrazine enters and exits chamber 12 through passageway 27 leading to quick disconnect 28. Upon loading chamber 12 with hydrazine, it is desired that a predetermined amount of volume in vessel 11 be allowed for hydrazine expansion. This is provided by ullage cylinder 29. As the piston is forced upward towards the pump, the narrowneck portion 31 of the piston enters ullage cylinder 29 and water within the ullage cylinder is trapped after the top of portion 31 contacts rubber o-ring 32 located in the circumference ofthe ullage cylinder. During loading, three way valve 36 prevents any flow from ullage cylinder 29 through conduit 38. This prevents further movement of piston 14.

Water which is forced out of water cavity 13 passes through opening 33 at the top of vessel 11 and through conduit 34, three way valve 36 and conduit 37 into the ambient water.

After chamber 12 is filled, the refueling means is disconnected at quick disconnect 28 and three way valve 36 is actuated to prevent flow through conduit 37 and to allow flow through conduit 38 into conduit 34. If the hydrazine within chamber 12 expands water trapped in ullage cylinder 29 is allowed to escape through relief valve 35 as piston 14 rises. The pressure in chamber 13 is released through the flow of water through conduit 34 and safety relief valve 35.

In operation, lever 26 is pumped to actuate pump 18 causing a flow of water into water inlet 21 through pump 18 and through passageway 22 into chamber 13 thus forcing piston 14 downward against the hydrazine in chamber 12. The hydrazine is thus forced through passageway 27 and quick disconnect 28. Quick disconnect 28 is connected to pressure feedback fuel control valve 39 which allows passage of hydrazine into a hydrazine decomposition reactor 19. The hydrazine decomposes-on the catalyst in the gas generator to produce an exhaust gas consisting of hydrogen, nitrogen, ammonia, and heat. A portion of this gas passes through feedback conduit 41 to be used in regulating pressure feedback fuel control valve 39 while the remainder of products from the reactor pass through heat exchanger 42 and onto gas power tool 43 via flexible line 44 quick disconnect 45 and safety release valve 46. The gas motor is employed, to operate an underwater power tool, swimmer propulsion unit or the like.

Exhaust from motor 43 passes through quick disconnect 47, flexible hose 48 and into gas inlet 23 of pump 18.

A first modification of the invention as shown in FIG. 2 employs a polyethylene bellows 249 as a hydrazine chamber with the remainder of cylindrical pressure vessel 211 serving as the water chamber. As the device is refueled by filling bellows 249 via a fuel line connected to quick disconnect 228 and passageway 227, bellows 249 elongates forcing water through opening 233 into conduit 234 and through two way valve 251 into the ambient water.

After bellows 249 is filled, two way valve 251 is shut off so that no water may flow through it thus allowing the only flow of water through conduit 234 to pass through safety relief valve 235. This allows for expansion of the hydrazine to force water out through safety relief valve 235. The hydrazine can now be forced out 4 of the bellows by allowing pump 218 to pump ambient sea water through inlet 221 and through passageway 222 into chamber 212. The pressurized water in chamber 212 causes the bellows to collapse forcing hydrazine through conduit 22'! and out of quick disconnect 228. A third modification operates similar to the bellows arrangement. Thev third modification shown in FIG. 3 employs a flexible polyethelene bag or self folding rollonet 349 for containing the hydrazine. The second the third modifications are otherwise similar in all respects with the elements being numbered in the 300s and with the last two digits of each reference numeral corresponding to the last two digits of the reference numerals of the first and second modifications.

I claim:

1. A portable underwater fuel feed system, comprismg:

a fuel chamber charged with a predetermined amount of fuel;

a water chamber;

a gas-driver hydraulic pump for pumping ambient water into said water chamber;

means in contact with the fuel and water for forcing fuel from said fuel chamber as water enters said water chamber;

a catalytic reactor;

a conduit connecting said fuel chamber to said reactor;

a gas driven motor;

a conduit connecting said reactor and'said motor for conveying the gas products from said reactor to said motor; and

a conduit connecting said motor and said pump for conveying the exhaust gas from said motor to said whereby the gas driven pump is controlled by exhaust gas from the motor to allow a flow of water into the water chamber causing pressurized fuel to be delivered to the reactor for producing a supply of gas sufficient to drive the motor.

2. The system of claim 1 further comprising:

a pressure feedback fuel control valve located in said conduit connecting said fuel changer to said reactor;

means conveying gas pressure information at the exit end of said reactor tosaid valve;

whereby said pressure remains essentially constant.

3. The system of claim 1 wherein said fuel forcing means comprises:

a cylindrical container;

a piston slidable along the axis of said container; and

a self folding rollonet attached to the bottom of said container and located within said container.

Claims

1. A portable underwater fuel feed system, comprising: a fuel chamber charged with a predetermined amount of fuel; a water chamber; a gas-driver hydraulic pump for pumping ambient water into said water chamber; means in contact with the fuel and water for forcing fuel from said fuel chamber as water enters said water chamber; a catalytic reactor; a conduit connecting said fuel chamber to said reactor; a gas driven motor; a conduit connecting said reactor and said motor for conveying the gas products from said reactor to said motor; and a conduit connecting said motor and said pump for conveying the exhaust gas from said motor to said pump; whereby the gas driven pump is controlled by exhaust gas from the motor to allow a flow of water into the water chamber causing pressurized fuel to be delivered to the reactor for producing a supply of gas sufficient to drive the motor.

2. The system of claim 1 further comprising: a pressure feedback fuel control valve located in said conduit connecting said fuel changer to said reactor; means conveying gas pressure information at the exit end of said reactor to said valve; whereby said pressure remains essentially constant.

3. The system of claim 1 wherein said fuel forcing means comprises: a cylindrical container; a piston slidable along the axis of said container; and said piston dividing said container into said water chamber and said hydrazine chamber.

4. The system of claim 1 wherein said fuel forcing means comprises: a cylindrical container; and a polyethylene bellows attached to the bottom of said container and located within said container.

5. The system of claim 1 wherein said fuel forcing means comprises: a cylindrical container; and a self folding rollonet attached to the bottom of said container and located within said container.