US2395113A - Mechanism for feeding combustion liquids to rocket apparatus - Google Patents

Description

Feb. 19, 1946; R.IH. GODDARD MECHANISM FOR FEEDING COMBUSTION LIQUIDS TO ROCKET APPARATUS Filed April 1', 1940 I Inc/e726 6 .78 v ms STEAM jagggmwri. a .41 W

Feb. 19, 1946. I R. H. GODDARD 2,395,113

MECHANISM FOR FEEDING COMBUSTION LIQUIDS To ROCKET APPARATUS Filed April 1, 1940 s Sheets-Shet 2 J6 ,IIIIIIIIIiIi//III Feb. 19, 1946. R. H. GODDARD 1 MECHANISM FOR FEEDING COMBUSTION LIQUIDS TO ROCKET APPARATUS Filed April 1, 1940 5 Sheets-Sheet 5 Patented Feb. 19, 1946 MECHANISM FOR FEEDING COMBUSTION LIQUIDS T ROCKET APPARATUS Robert H. Goddard, Roswell, N. Men, assignor of one-half to The Daniel and Florence Guggenheim Foundation, New York, N. Y., a corporation of New York Application April 1, 1940, Serial No. 327,257

28 Claims. (01. (SO-35.6)

This invention relates to rocket apparatus of the type in which flight is sustained by continuous combustion of suitable liquids, such as gasoline and liquid oxygen.

In this application, wherever reference is made in oxygen, it is to be understood that the oxygen is in a liquid state unless otherwise specified, and the term gasoline is to be understood as including other liquid fuels having similar characteristics.

It is the general object of my present invention to provide improved means for continuously feeding gasoline or other liquid fuel and oxygen under high pressures to a combustion chamber.

A further object is to provide improved means for developing power to produce such high pressures and to return condensed products for further use. I also provide improved and novel means for maintaining substantially uniform ressure in the oxygen and liquid fuel containers as the liquids therein are gradually withdrawn.

Further features of my invention relate to automatic control of pressures in my improved feeding mechanism, to provision for automatic closing of certain valves on exhaustion of the liquids in said containers, and to certain safety devices to be described.

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawings, in which Fig. 1 is a diagrammatic view, partly in section, of my improved feeding mechanism;

Fig. 2 is a transverse sectional view of the oxygen container. taken along the line 22 in Fig. 1;

Fig. 3 is a detail view' of a modification to be described.

Fig. 4 is a side elevation of a filter cone;

Fig. 5 is a sectional plan view of'a nitrogen container;

Fig. 6 is a perspective view of a separator for liquid and gaseous nitrogen;

Fig. 7 is a detail perspective view of a pump and turbine for feeding liquid oxygen;

Fig. 8 is a perspective view of a portion of an insulating'covering for the oxygen tank;

Fig. 9 is a side elevation of a detachable cou-. p s;

Fig. 10 is aside elevation of a certain tanksupporting structure;

.Fig. 11 is a perspective view of a brace memher;-

Fig. 12 is a side elevation, partly in section, of

a float device which controls the closing of certain valves on exhaustion of either gasoline or oxygen;

Fig. 13 is a side elevation, partly in section, of a control valve for gasoline or oxygen;

Fig. 14 is a sectional side elevation of a control valve for nitrogen, and actuating mechanism therefor;

'Fig. 15is a sectional side elevation of certain oxygen and gasoline reducing valves and control mechanism therefor;

Fig. 16 is a sectional view of a valve to be described;

Fig. 17 is a detail view, partly in section, of a combined check valve and coupling member;

Fig. 18 is a front elevation, partly in section, of a solenoid-operated three-way valve;

Fig. 19 is a sectional elevation of a special check valve to be described;

Fig. 20 is an enlarged sectional elevation of a shielded vent and check valve to be described;

Fig. 21 is a diagrammatic side elevation of a launching frame;

Fig. 22 is a detail front elevation of a rotary pump, partly in section to show a sealing device; and

Fig. 23 is a partial sectional front elevation showing an auxiliary turbine nozzle.

In Fig. 1, I have shown a diagrammatic assembly of the various parts of my improved feeding mechanism in association with a combustion chamber 16 and nozzle H, which latter parts are shown on a reduced scale as in themselves they form no part of the present invention. It will be understood that all of the parts shown in Fig. 1 will be assembled within a suitable rocket casing, with the combustion chamber i6 and nozzle I'I disposed at the rear end thereof, as shown, for instance, in my prior Patent No. 2,183,311.

Briefly described, my invention includes an oxygen tank 20. a gasoline tank 4|], and a nitrogen tank 10, all at moderate pressures. Liquid oxygen is delivered from the tank 20 through a pipe 2| (Fig. 1) and valve 22 to a pump 23 which is connected to the combustion chamber 16 through a pipe 24 and valve 25. The pump 23 is driven by a turbine 26 and greatly increases the pressure of the oxygen before delivery thereof to the combustion chamber.

Gasoline is similarly delivered through a pipe 4| and valve 42 to a ump 43 which is connected through a pipe 44 and valve 45 to the combustion chamber IS. The pump 43 is driven by a turbine 46 and feeds gasoline at high pressure to the combustion chamber.

The turbines 2'9 and 48 may be conveniently operated by steam from a boiler 99 which is delivered to the turbines through a pipe II and branch pipes 92 and B9. The boiler 90 must be of very light weight but the details of construction of the boiler form no part of my present invention. It may be briefly stated that water is evaporated and steam formed in the boiler 59 by direct contact of the water with hot gases resulting from the combustion of a mixture of oxygen delivered through a branch pipe 21 and gasoline delivered through a branch pipe ll. The pipe 21 is provided with a reducing valve 29 and the pipe 41 with a reducing valve 49.

Exhaust steam from the turbines 29 and 49 is delivered through pipes 50, II and 52! to a condenser 59 in which the steam is condensed by the evaporation of a spray of liquid oxygen supplied through a branch pipe II and a valve 99. The condensed steam is then returned through a pipe 51, pump "and pipe 99 to the boiler 50. The pump 59 is driven by a small turbine 60 which receives operating steam through a branch pipe Cl and a valve 9!". The details of construction of. the condenser 89 form no part of my present invention. v

The oxygen gas evaporated in the condenser 89" is returned to the oxygen tank 20 through a pipe 92. This gas also contains more or less water vapor and also carbon dioxide from the boiler 99, both of which substances freeze at temperatures above the freezing point of oxygen.

In order to keep these solidified particles of water or carbon dioxide from clogging the oxygen delivery pipe 2!, I introduce the pipe 92 tangentially into the tank 20. as shown in Fig. 2, so that the water and carbon-dioxide will solidify near the outer wall of the tank. I also provide a perforated conical filter plate 94 (Figs. 1 and 4) in the tank. 20 by which these solid particles will be separated and prevented from falling to the bottom of the tank. The plate It may be covered with a fine wire mesh screen if considered desirable.

It will be noted that the pumps 29 and 49 and the turbines 29 and 49 are oppositely disposed to equalize weight,- and it is also desirable to have these units rotate in opposite directions to neutralize gyroscopic force.

It is important that gas pressure be maintained substantially constant in the tanks 29 and 40 during the flight of the rocket apparatus, as these tanks are necessarily madewith very thin walls in order to save weight and are stiilened by intemal pressure. The tanks may also be externally reenforced as shown in my prior Patent No. 2,109,529. A constant internal pressure is also desirable to assist the pumps 23 and 49 in delivering liquids therefrom at uniform high pressure.

In order to maintain such uniform pressure in the tanks 20 and 40 as the liquids are gradually withdrawn, I provide the auxiliary tank Ill, preferably submerged in oxygen within the tank 29 as shown in Fig. 1. The tank 'lli may be filled with a liquifled inert gas such as liquid nitrogen by injecting nitrogen gas under pressure through a v feed pipe H. valve 12 and coil I9. said coil being It is desirable to prevent the liquid nitrogen from falling below the temperature of the liquid oxygen, due to nitrogen evaporation in the tank 19 as the nitrogen supply is drawn 01! during the operation of the rocket apparatus. I accordingly provide a series of transverse tubes 14 (Figs. 1 and 5) through which oxygen may circulate to equalize the temperature of the nitrogen.

In order to change the liquid nitrogen to a nitrogen gas under a moderate pressure, the

liquid nitrogen is delivered through a jacketed tube II, a jacketed reducingvalve l9. and a pipe I1 to a coil 19 which surrounds the combustion chamber l9 and nozzle l'l. asshown in Fig. 1. Heat is transferred from the combustion chamber and nozzle to the ntirogen in the coil 18, raising the temperature thereof and evaporating the liquid nitrogen so that nitrogen gas is delivered to the return pipe I9.

Small drops or particles of liquid nitrogen may be mingled with the nitrogen gas, and it is not desirable that this liquid nitrogen enter the oxygen tank 20 where it would dilute the liquid oxygen. Accordingly. the return pipe 19 is connected to a separator 99 (Fig. 6) where the liquid nitrogen. together with a part of the nitrogen gas, is delivered through centrifugal action to a pipe 9| and dry nitrogen gas is delivered to a pipe .2. The pipe 9| connects through a check valve 99 to the upper end of the gasoline tank 49, and the pipe 92 connects through a check valve 94 to the upper end of the oxygen tank 20. Nitrogen gas under pressure thus fills the upper ends of the tanks 20 and 40 and maintain substantially constant pressure therein. regardless of the withdrawal of liquids therefrom.

The gasoline in the tank 49 is at a relatively high or ordinary temperature, so that any drops of liquid nitrogen delivered through the pipe II will be immediately evaporated in the tank 49 and will not dilute the gasoline. The check valves 99 and 94 in the pipes 9| and 92 open toward the tanks 29 and 40 but prevent flow in a reverse direction, so that there can be no transfer of gasoline vapor to the tank 29 or oxygen vapor to the tank 49. Explosive mixtures are thus avoided. 4

The jacketed reducing valve It is controlled in its operation by the pressure in a pipe 99. the

upper end of which is connected into the pipe 92 previously described. The construction and operation of the valve 19 is shown in detail in Fig. 14.

The reducing valve 19 (Fig. 14) comprises a valve member 99 mounted at the upper end of a rod 9| guided in a bearing 92 and extending downward through a bellows packing 93 to the bottom plate of a bellows member 94 and to a lever 95. A spring 99 in the bellows member 94 normally holds the valve open. The control pipe 95 previously described is connected into the space between the bellows member at and the casing 91. Obviously a suilicient ,increase in pressure in this restricted space will compress the spring 98 and raise the valve member 99 to closed position, the bellows member 93 acting merely as packing.

The lever 99 may be provided with a pull cord 99 by which the valve I9 may be held closed except during rocket propulsion. A jacket tube 99 surrounds the reducing valve 19 and is freely connected to the interior of the tank 29. so that the tube 99 is at all times filled with liquid oxygen which prevents gas-bind in the reducing valve.

An alternative method of supplying pressure to a liquid fuel tank 40' containing a fuel of high vapor pressure, such as butane, is shown in Fig. 3, where a small part of the liquid fuel is delivered through a pipe I and reducing valve IOI to a coil I02 surrounding a combustion chamber I8 and nozzle I 1' thereby evaporating the liquid fuel and supplying vapor under reduced pressure through a return pipe I03 to the upper end of the tank 40. A cross connection I 04 from the return pipe I 03 to the reducing valve IOI regulates the operation of this modified apparatus, the construction and operation of the valve IOI being similar to that of the reducing valve 16 shown in Fig. 14 and previously described. Both the coils and I02 may be wound on the same chamber and nozzle.

The pressure which causes the butane or other low boiling fuel to fiow from the tank 40' through the coil I 02 will be the .dlfl'erence in head between the tank 40 and the chamber I8, and also the pressure due to the acceleration of the rocket apparatus during flight. As both the liquid and the evaporated gas are confined in a single closed system, the gas pressure will be substantially the same both above and below the body of liquid and the natural down-flow of the liquid by gravity will not be affected by the gas pressure. influenced by changes in acceleration of the aircraft and would result in an excessive rise in gas pressure, if not controlled by the reducing valve IOI which is responsive to gas pressure in the return pipe I03. A construction similar to that shown in Fig. 3 may also be provided for the oxygen tank 20 if so desired, in which case the nitrogen tank may be omitted.

The construction and operation of the pressure-reducing valves 29 and 43in the boiler connections is shown in detail in Fig. 15. The valve 20 comprises a valve member 'fl0'which, when free to move, is closed by a spring III and thus interrupts flow through the pipe 21. A rod H2 is secured in a plate I I3 and is slidable in a fixed guide I I5. A spring I I6 tends to force the rod I I0 downward to depress and unseat the valve member III). The oxygen pressure in the space between a bellows member H1 and the casing II8 resists the pressure of the spring II6.

Consequently, an increase in pressure in the pipe 21'lifts the rod H2 and allows the valvemember I I0 to move toward closed position, while a decrease in pressure allows the spring II8 to depress the rod I I2 and valve member'I I0, thereby allowing increased flow through the pipe 21. A jacket I I9 surrounds the reducing valve 29 and is connected by a pipe I I 9 to the pipe 55, which in turn connects through the delivery pipe 2| to the oxygen tank 20. Gas-bind of the oxygen valve 29 is thus prevented.

The gasoline reducing valve 49 is of exactly similar construction, except for omission of the jacket H9 and oxygen connection I I9. The reducing valve 49 comprises the valve member I20, the spring I2I. the rod I22, the spring I26, bellows member I21 and easing I28, all as previously described.

It is sometimes desirable to allow the reducing valves 29 and 40 to close, regardless of the pressures in the pipes 21 and 41. Accordingly I connect the upper ends of the rods H2 and I22 to levers I30 and I3I, which levers have a pin and slot connection to a stud I32 carried by a yoke or frame I33 which is connected to the upper end of a rod I 34. The lower end of the rod I34 is fixed to a plate I35 forming the lower end of a bellows The rate of flow will, however, be

member I38 enclosed in a casing I21. A pipe I38 is connected to the space between the bellows member I38 and the casing I31. If gas under pressure is admitted through the pipe I38, the bellows member I36 will be compressed, raising the yoke I33 and levers I and I3I and thus lifting the rods H2 and I22 away from the valve members H0 and I20, which are then free to be closed by their springs III and I2I.

The gas under pressure for the pipe I38 may be initially supplied through a hose connection I40 Figs. 1 and 9), a check valve HI and a coupling member I4Ia. A latch I42 normally secures the hose and coupling together but may be released by a manual pull on a cord I43. The valve and, coupling I (Fig. 1) is connected by a pipe I44 to a three-way valve I45 (Fig. 18) which may be set to connect the pipe I44 to the pressure pipe I38 previously described or to vent the pipe I38.

The detail structure of the check valve MI and coupling member MI is shown in Fig. 17 and comprises a check valve element I46 seated against a conical seat I41 by a spring I48, the valve stem being slidable in a perforated guideplate I40.

The three-way valve I45 is shown in detail in Fig. 18 and comprises a rotary valve member I mounted in a casing having ports I56, I51 and I58 to which the pipes I44 and I38 and a vent pipe I59 are connected. The rotary valve member I55 is provided with an arm I55 connected to a plunger 240 of a solenoid I40, the operation of which will be hereinafter described.

After suillcient vapor pressure is developed in the oxygen tank 20, or after sufllcient outside pressure has been supplied to the tank 20 through the hose 200, the hose I40 may be disconnected. The pressure in the pipe I38 will then be supplied through a pipe connection I50 from the upper end of the tank 20. A check valve I5I prevents reverse flow in the pipe I50. Branch pipes I52 and I53 supply pressure to liquid seal devices in the pumps 23 and 43, the specific construction of which forms no part of my present invention.

One form of such a liquid seal device is shown in Fig. 22 and comprises an annular flange 250 on the pump shaft 25I which is engaged by an annular disc 252 which loosely encircles the pump shaft 25I and which forms the movable outer end of an annular bellows member 253,. to which the pipe I52 is connected through 'a channel 254 in the pump casing. When pressure is applied through the pipe I52, the disc 252 is forced firmly in contact with the flange 250, thus effectively 7 sealing device may be provided for the pump 43.

The preferred construction of the oxygen valve 25 in the pipe 24 is shown in detail in Fig. 13 and comprises a valve I60 supported on a rod IBI and extending downward through a bellows packing I62 to a lever I63 having a pull cord I64.

When the apparatus is not in operation, the valve- 25 may be closed manually by use of the cord I64, but otherwise the valve 25 is normally open. The gasoline valve 45 in the pipe 44 is of similar construction and operation.

A spark-plug or other suitable igniter I66 is provided for starting combustion in the chamber I6 when the apparatus is to be put in operation. Because of the small clearance in the pumps 23 and 43, a vent pipe I61 (Fig. 1) connects the upper end of the oxygen feed pipe 24 through a special check valve I 68 to the upper end of the oxygen tank 20. A similar vent pipe I10 connects the gasoline feed pipe 44 through a special check valve "I to the upper end of the gasoline tank 48. A shut-oil valve I 1 I may also be provided in the pipe I18 adiacentthe tank 48. The special check valves I88 and "I open away from the tanks 28 and 48 and are normally slightly open to vent the pumps 28 and 48 but close automatically as soon as the pumps begin to develop any substantial pressure.

The construction of the special check valve I88 is shown in detail in Fig. 19 and comprises a valve element I12 normally held slightly away from its conical seat I18 by a light spring I14, the valve stem being slidable in a perforated guide member I14. When the oxygen pump 28 starts to operate, a rapid flow takes place in the direction of the arrows k in Fig. 19, which closes the check valve I88 and holds it closed so long as the pump is in active operation. The construction of the special valve I1I is identical with that of the valve I88 above described.

A safety valve I18 is provided for the tank 28,

-to relieve any excessive pressure caused by evaporation of the liquid oxygen. This safety valve is preferably surrounded by a light metal shield I 18 to prevent freezing of the valve. The shield is mounted in spaced relation to the valve and has a vent opening of reduced cross section at the top thereof. As the oxygen gas escapes, frost may form on the outside of the shield I18 but the oxygen gas, being perfectly dry, will not form any frost on the valve I18 or within the shield I18. Any water which may have been present in the liquid oxygen will have been previously frozen to solid particles and deposited on the screen 84.

A vent and check valve I'll in the top of the oxygen tank 28 is provided for venting the tank while it is being filled preparatory to starting. This vent valve is allowed to close under tank pressure after the tank has been filled. This valve I11 is provided with shields I18 to prevent freezing, as previously described for the valve I15.

The detailed construction of the valve I11 may be as shown in Fig. 20 and comprises a valve element I11 normally pushed upward and seated by a spring I11 but held open by a crosspin I11 while the oxygen tank 28 is being filled. After the tank is full, the pin I11 is withdrawn and the valve element I11 moves upward against its seat under the influence of the spring I11 and also of the pressure in the tank 28. The shields I18 are also clearly shown in Fig. 20.

4 A safety valve I18 is provided for the gasoline tank 48 and a similar safety valve I88 for the nitrogen tank 18, the valve I88 being located in the feed line to the nitrogen tank.

A special vent valve I8I (Figs. 1 and 16) is provided in the gasoline feed pipe 44, which valve comprises a hinged valve member I82 adapted to seat in either one of two openings I88 or I84. When in the full line position shown in Fig. 16,

the member I82 closes the lower end of the pipe I44 and leaves the vent I84 above the valve open. When the member I82 is moved by operation of a pull rod I82. manually or otherwise, to the dotted line position, the vent opening is closed and the pipe 44 is open. When the apparatus is not in use, the valve I82 is moved to the full line position, shutting off the lower end of the pipe 44 and preventing gasoline vapor from drifting into the combustion chamber I8 and possibly forming an exniosive mixture.

For additional safety, I provide a branch connection I88 from the nitrogen gas pipe 18 to the combustion chamber I8. This pipe is controlled aseans if some residual gasoline vapor has been left in the chamber.

Auxiliary starting nozzles of well known construction are provided in the turbines 28 and 48 and provision is made for supplying pressure from an outside source for initially starting the turbines, such provision comprising a detachable hose I88 latched to a check valve I8 I and coupling member I88 which is connected through a pipe I82 and branch pipes I83 and I84 to the turbines 28 and '48 respectively. The specific constructionof the auxiliary nozzles forms no part of my present invention but may be as disclosed in F18. 23.

The tanks 28 and 48 are preferably provided with semispherical ends, as shown in Figs. 1 and 10, and may be separated and held in fixed relation by a skeleton frame structure comprising rings I81 and braces I88 (Fig. 10), which parts are preferably tubular and very light and maintained under pressure. forced with a wire winding, all as set forth in my prior Patents Nos. 2,090,038 and 2,109,528.

An additional pressure hose 288 is detachably connected through a check valve 28I and coupling member 28l to the nitrogen gas pipe 18, so that gas pressure may be supplied to the tanks 28 and 48 before the nitrogen pressure apparatus is started in operation.

Any suitable frame-work may be provided for launching my improved rocket craft R. and such frame-work is shown diagrammatically in FIB. 21, which shows the craft R held in upright position by braced guide-members 282, which provide a vertical guideway open at its upper end.

As the disconnecting and pulling off of the hoses I48, I88 and 288 may exert a considerable sidewise pull against the casing of the rocket apparatus, I preferably provide a brace member 284 (Figs. 11 and 21) hinged to a fixed outside support 288 and having an end portion 288 curved to fit the surface of the rocket craft R. A stop 281 normally supports the member 284 but said member is free to swing toward the dotted line position in Fig. 11 and away from the rocket as the upward flight thereof begins.

It is desirable to have the oxygen tank 28 effectively heat-insulated prior to flight to prevent oxygen evaporation, and it is also desirable to remove a substantial part of this insulating covering when flight is about to take place. If any boiling of the oxygen occurs during flight. this is not objectionable but on the other hand assists in maintaining pressure in the oxygen tank and helps to conserve the supply of liquid nitrogen.

I accordingly provide a felt covering for the lower portion and sides of the tank 28 which comprises an end pad 2I8 (Fig. l) which remains permanently in position and two semicylindrical pads 2 (Fig. 8) which are hinged together at one side of the tank as indicated at 2I2 and are latched at the opposite side as indicated at 2 I3. A pull cord 2 I4 provides means for quickly unlatching the pads 2 which then swing apart and may be removed by a further pull on the cord 2I4 or in any other convenient manner. The pads 2 are provided with suitable light metal frames 2I8 to retain them in shape.

Whenever either the oxygen or the gasoline They'may also be reen- I will be made to the nitrogen feed pipe II.

supply is exhausted, it is desirable to close both valves 25 and 45 promptly, so that the remain- Ing liquid in the tank not exhausted may not continue to feed into the combustion chamber after combustion can no longer be sustained and thus be wasted. The valves 25 and 45 are accordingly provided with suitable additional electrical control mechanism, such as solenoid plungers 220 and 220- (Fig. 13) and solenoid coils 22I and 22I connected by wires 222 to a suitable supply ofelectricity. This circuit is controlled by two switches 224, one of which is shown in Fig. 12. These switches are mounted in parallel, with one switch associated with the oxygen tank 20 and the other with the gasoline tank 40.

228, so that abrupt movement of the liquid in 7 the tank cannot accidentally depress the float and close the contacts.

Operation The use and operation of many parts of my improved feeding mechanism have been clearly indicated in the preceding description but a brief general statement of the operation of the entire feeding mechanism appears desirable.

Starting with the tanks empty, the hoses I40, I96 and 200 will be coupled to the check valves I4I, I9I and 2M, and a similar hose connection A suitable gas, under pressure, is admitted through the pipes I40 and I44 to the three-way .valve I45, which valve is set to connect the pipe I44 to the pressure pipe I36 and to the branch pipes I52 and I53. Pressure in the branch pipes will seal the bearings of the pumps 23 and 43 and prevent leakage therethrough while the pumps are at rest, the sealing means being disclosed'in Fig. 22 and being more fully shown and described in my prior Patent #2,281,971, issued May- 1942. After the oxygen tank 20 has been filled and is under pressure, this pressure will then be communicated-through the pipe I50, which connects into the pipe I38 through the check valve I5I. This valve prevents reverse flow of gas when the tank 20 is at a lower pressure.

Pressure in the pipe I38 also causes the bellows member I36 (Fig. 15) to operate to release the reducing valve members H0 and I20 and allow these valves to close, even when there is no pressure in the boiler 50. This avoids leakage of oxygen and gasoline through the boiler to the turbines 26 and 46, which would not only be wasteful but might cause an explosive mixture.

The tanks 20 and 40 are supplied with liquid oxygen and gasoline respectively through feed pipes 230 and 23I having shut-off valves 232 and 233 and adapted to receive suitable hose connections. After the tank 20 is filled, the vent check valve I" is released and allowed to close.

The nitrogen tank 10 is filled by feeding nitrogen gas under pressure through a hose connection to the pipe II, coil I3 and tank I0, all as previously described. The reducing valve I6 is solid, thus becoming inoperative.

the turbines 26 and 46.

at this-time closed. After the tanks 20, 40 and I0 are filled, the hose connections to the pipes 230, 23I and I0 are disengaged. 1

The three-way valve I45 is then set-to vent the pipe I38, releasing the pressure on the pump bearings; and alsofreeing the valves 29 and 49 which control the flow of oxygen and gasoline to the boiler 50 and which thus control the production of steam to drive the turbines 26 and 46. Combustion may be started in the boiler by an igniter 235, previously rendered active.

A short time before starting flight, the valve 22 is opened to allow liquid oxygen to flow to the pump 23 and valve 25. It is desirable to keep the valve 22 closed until shortly before flight, as liquid oxygen remaining for any considerable time in the pump 23 or in the pipe connections below the valve 22 would cause these parts to accumulate frost and eventually freeze The valves 25 and 45 are now opened to allow oxygen and gaso line to flow into the combustion chamber I6, the igniter I66 having been previously rendered operative and the vent valve I6I having been previously closed to the outside air. As soon as the pumps start, pressures are built up in the pipes I61 and H0, which pressures close the check valves I66 and I'll.

Nitrogen gas from an outside source and under substantial pressure, as 50 to 100 lbs. per square inch, is initially supplied,,through the hose 200 and check valve 20I to the pipes I9, 8| and B2 and thence to the tanks 20 and 40. Also, outside gas or steam under heavy pressure is supplied through the, hose I and pipes I92, I93 and I94 to operate the auxiliary starting nozzles in Before flight actually commences, the felt pads 2I I are unlatched by a pull on the cord '2I4 and are removed from the oxygen tank 20.

After combustion is under way in the combustion chamber I6 and in the boiler 50, the spark-plugs or igniters I66 and 235 may be disconnected or rendered inoperative. As soon as the boiler 50 has developed working pressure, the hose connections I40, I90 and 200 are discon-.

nected.

It is desirable that the connections to the pipes I40, I90 and 200 be removed quite promptly for the following reasons:

If pressure is maintained too long through the hose I90, the speeds of the turbines 26 and 46 will become excessive. This outside operating force should be discontinued as soon as the boiler 50 has developed working pressure. If the tanks 20 and 40 are supplied for too long a time with outside nitrogen pressure through the hose 200,

the liquid nitrogen in the tank I0 will not flow through the jacket coil I8, and the temperature of the coil I8 and also of the combustion chamber I6 and nozzle I! will become excessive and much higher than the temperature for which they were designed. The hose I40 can be disconnected, as pressure for the pump bearings will now be supplied from the oxygen tank through the pipe I50.

The apparatus is now in condition for sustained flight, which flight will normally continue until the supply of one or the other of the combustion-liquids is exhausted, whereupon one of the float-controlled switches 224 will be closed. thus energizing the solenoids 22I and 22b (Fig. 13) to shut off from the combustion chamber the exhausted tank and also the other tank which is not yet exhausted.

Closing of either switch as also energizes the solenoid 2 to close the three-way valve Ill,

putting pressure on the pump seals and releasing the valve members Ill and I (Fig. 15) to close as previously described. These pump seals must be closed to prevent lossof pressure in the tanks and I also depends quite largely on the maintenance of substantial pressure in these tanks during flight. If excessive gas pressure, however, is developed by evaporation or otherwise in any of the tanks 20, I or ill, this pressure will be relieved through the safety valves "5,119 and I80 respectively. The pressure and rate of feed of gasoline and oxygen to the boiler may be controlled by changing the pressure of the springs H8 and I2! (Fig. 15) and the flow of condensed water to the boiler may be controlled by the valve 6i which. supplies steam to the turbine 60. Through these several adjustments the speed of the pumps 23 and 43 may be varied.

On recovery of the apparatus after flight, the pressure in the tanks 20, and 10 may be reduced if desired, by manually opening the safety valves on said tanks.

From the foregoing description it will appear that I have provided new and improved mechanism for continuously feeding combustible liquids to a combustion chamber during the flight of a rocket, together with means for maintaining substantially uniform pressure in the storage tanks as the supply of liquids is gradually diminished. I have also provided auxiliary devices of novel construction and particular design to operate under the unusual conditions arising from the use of an extremely cold oxidizing liquid such as liquid oxygen.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. In a rocket, combustion apparatus comprising separate tanks for combustible and oxidizing liquids, means to intermingle said liquids and to produce continuous combustion thereof, and means to evaporate an inert liquid to an inert gas under pressure and to automatically supply said inert gas under uniform pressure to those parts of said tanks not filled by said combustible and oxidizing liquids, and said inert gas thereby maintaining substantialhr uniform pressure in both of said tanks as the liquids are withdrawn therefrom.

2. In a rocket, combustion apparatus comprising a tank containing combustible liquid, a second tank containing a very cold oxidizing liquid. a third tank immersed in said oxidizing liquid and containing an inert liquid, and means to evaporate a portion of said inert liquid to produce gas pressure in said first and second tanks 70 as said tanks are gradually emptied during flight.

3. The combination in a rocket as set forth in claim 2, in which the combustion apparatus embodies a combustion chamber and nozzle, and in which said inert liquid is rogressively evaporated .in a coil surrounding said chamber and nozzle, the gas from said evaporation being delivered to said first and second tanks to maintain pressure therein.

4. In a rocket, combustion apparatus comprising separate tanks containing combustible and oxidizing liquids, a combustion chamber and nozzle, an auxiliary boiler, pumps to feed said liquids to said combustion chamber under high pressure, driving means for said pumps, and means to produce a gas under pressure in said boiler for the driving means of said pumps by combustion of a portion of said liquids in saidboiler at reduced pressure.

5. The combination in a rocket as set forth in claim 4 in which a condenser is provided to receive the exhaust fluid from said driving means and which is eflective to condense said exhaust fluid by evaporation of a portion of the oxidizing liquid in said condenser.

6;The combination in a rocket as set forth in claim 4, in which automatic meansis provided to regulate the reduced pressures of the combustible and oxidizing liquids delivered to said boiler.

'l. The combination ina rocket as set forth in claim 4, in which means is provided which is responsive to changes in liquid level in said tanks and which is eflective to automatically shut off all supply of said liquids to said boiler when liquid is exhausted in either of said tanks.

8. The combination .in a rocket as set forth in claim 4, in which means is provided which is responsive to changes in liquid level in said tanks and which is eflective to automatically shut oil the supply of either liquid to said combustion chamber when the other liquid is exhausted.

9. In a rocket apparatus, a combustion chamher, a pipe to feed liquid fuel thereto, a shut-ofl valve in said pipe, and additional means to close 60 the lower part of said feed pipe at a point adjacent to said combustion chamber, the upper part of said feed pipe having a vent opening closely adjacent to said additional closing means, and said additional closing means being alternately 45 effective to close said vent opening when said feed pipe is open to said combustion chamber and to open said vent opening to provide an escape for combustible vapor when said feed pipe is closed by said additional closing means.

10. In a rocket apparatus, a tank for liquid oxygen, means to inject mixed steam and vapors into said tank in a tangential direction, whereby congealed particles will be thrown to the outside of said tank, and means to collect said particles.

11. In a rocket apparatus, a tank for liquid oxygen, means to inject mixed steam and vapors into said tank in a tangential direction, whereby congealed particles will be thrown to the outside of said tank, and a conical screen to collect said particles near the outer wall oi said tank.

on evaporation providing an inert gas under pressure, a connection between said inner tank and said oxygen tank through which said inert gas under (pressure provides a part of the operating pressure in said oxygen tank, and means to keep the temperature of said two liquids substantially equal as the inner tank is gradually emptied and as a part of said inert liquid evaporates, said means comprising heat exchange devices associated with said inner tank and constructed and arranged to bring portions of liquid oxygen into intimate heat exchange relation with the remaining portion of inert liquid, thereby maintaining thetemperature of said inert liquid substantially at the temperature of the liquid oxygen and thereby preventing a drop in pressure in said inner tank as said inert liquid evaporates.

13. In a rocket apparatus, tanks for liquid fuel, liquid oxygen and a liquid inert gas, means to evaporate said liquid inert gas and deliver said as under pressure to said fuel and oxygen tanks, and means to separate particles of said liquid inert gas from the gas delivered to said oxygen tank and to deliver said particles to said fuel tank.

14. The combination in a rocket apparatus as set forth in claim 13, in which means is provided in said inert gas connections to prevent flow of liquid fuel to said oxygen tank or oxygen to said fuel tank.

15. In a rocket apparatus, separate tanks for liquid fuel and oxygen, separate valves controlling the flow from said tanks, and means to effect operation of said valves-to prevent flow of liquid from either tank after the other tank has been emptied, said means comprising a separate float associated with each tank, an electric circuit controlled thereby, anda pervious shield which prevents movement of said float by movement of liquid in said tank.

16. In a. rocket apparatus, apump, fluid-operated means to drive said pump, pressure-operated sealing means for the bearings of said pump, a boiler to supply steam to drive said pump, a tank for liquid fuel, a tank for liquid oxygen, means to feed said liquid fuel and said liquid oxygen from said tanks to said boiler, a single valve controlling the operation of said feeding means and the operation of said sealing means, and devices effective to render said single control valve operative to cause stopping of the feed of any liquid to the boiler and also to cause pressure to be applied in said sealing means, all in the event of exhaustion of the supply of liquid in either of said tanks.

1'7. In a rocket apparatus, a liquid fuel tank,

a combustion chamber, a coil about said chamber,

in said venting means prior to the placing of said rocket apparatus in operation.

21. In a rocket apparatus, a combustion chamber, a pipe to feed liquid fuel thereto, a liquid fuel tank, means to close one part of said feed pipe, a vent pipe connecting an adjacent part of said pipe to the top of the liquid fuel tank, a check valve in said vent pipe closable toward said tank by excess of pressure in said adjacent part, and means to admit liquid fuel under pressure to the vented part, thereby closing said check valve prior to the operation of the said rocket apparatus.

22. In a rocket apparatus, a combustion chamber, a liquid oxygen tank, a pipe to feed liquid oxy en from said tank to said chamber, means toshut off the lower part of said feed pipe, means to vent an adjacent upper part of said feed pipe through a connection which extends to the top of the liquid oxygen tank, said venting means including a check valve effective to open toward said feed pipe on substantial drop in pressure in I said vented upper part of said feed pipe, and

means to introduce liquid oxygen under pressure to said vented upper art and thereby closing said check valve in said venting means prior to the placing of said rocket apparatus in operation.

23. In a rocket apparatus, a combustion chamber, a pipe to feed liquid oxygen thereto, a liquid oxygen tank, means to close one part of said feed pipe, a vent pipe connecting an adjacent part of said pipe to the top of the liquid oxygen tank, a check valve in said vent pipe closable toward said tank by excess pressure in said adjacent part, and means to admit liquid oxygen under pressure to the vented part, thereby closing said check valve prior to the operation of said rocket apparatus.

24. In a'rocket apparatus, a combustion chamber, a pipe to feed liquid oxygen thereto, a liquid oxygen tank, means to shut off the lower part I of said feed pipe, a vent pipe connecting an adjathe lower end of said tank being connected to the upper and cooler end of said coil and the lower and heated end of said coil being returnconnected to the top of said tank, whereby liquid fuel vapor pressure is maintained in said tank as liquid fuel is withdrawn therefrom.

18. The combination in rocket apparatus as set forth in claim 1'7, in which a reducing valve in the tank-to-coil connection is controlled by the liquid fuel vapor pressure in the return connection.

19. In a rocket apparatus, a combustion chamber, pipes supplying liquid fuel and a liquid oxidizing agent to said chamber, means to ignite said fuel, and means to admit a portion of inert gas to saidchamber-prior to initial ignition to moderate the initial combustion.

20. In a rocket apparatus, a combustion chamber, a liquid fuel tank, a pipe to feed liquid fuel cent part of said pipe to the top of the liquid oxygen tank, a check valve in said vent :pipe closable toward said tank by excess pressure in said adjacent part, and means for pre-cooling the vented parts by the admission of liquid oxygen thereto prior to the operation of said rocket apparatus.

25. In a rocket apparatus, a pump, fluid-operated means to drive said pump, pressure-operated sealing means for the bearings of said pump, a boiler to supply steam to drive said pump, a tank for liquid fuel, a tank for liquid oxygen, means to feed said liquid fuel andsaid liquid oxygen from said tanks to said boiler, pressure-regulating valves for said fuel and oxygen feeding means effective to maintain a predetermined pressure in said .boiler, and a single valve effective to control the operation of said sealing means and also to control the operation of said pressure-regulating valves for said feeding means.

26. In a rocket, combustion apparatus comprising separate tanks containing combustible and oxidizing liquids, a combustion chamber and nozzle, pumps to feed said liquids to said combustion chamber under high pressure, sealing means for said pump, turbines to drive said pumps, a boiler to supply steam to drive said turbines, valves to regulate the pressure of the liquids fed to said 8 v aseaue 27. The combination in a rocket as set forth in I claim 26, in which said auxiliary means comrises a plurality 01' external hoses detachably connected to the parts in said rocket actuated thereby.

28. The combination in a rocket as set forth in claim 26, in which said auxiliary means comprises

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