US2785635A - Tank submerged air driven fuel pumping system - Google Patents

Description

March 19, 1957 1-. w. JOHNSON TANK SUBMERGED AIR DRIVEN FUEL PUMPING SYSTEM Filed Oct. 23, 1953 wOwZIUQ 0 1M 'EXTOR. THOMAS W JOHNSON nited States Patent TANK SUBMERGED AIR DRIVEN FUEL PUMPING SYSTEM Application Uctober 23, 1953, Serial No. 387,939

4 Claims. (Cl. 103-87) This invention relates to an air driven fuel pump of the centrifugal type which finds particular use for providing fuel for the afterburner nozzles, the main engine, or both in a jet engine. While the invention finds this particular use, it is, however, capable of Wider application.

An object of the invention is to provide a tank submerged air driven centrifugal fuel pump system that is useful, in providing fuel for jet engine use.

A further object of the invention is to provide new and useful improvements in submerged air driven centrifugal fuel pump systems.

The invention further lies in the particular organization and arrangement of its various elements, as well as in their cooperative association with one another.

In the cross-section drawing, a tank submerged air driven fuel pumping system is disclosed embodying the invention.

Now referring to the drawing, there is disclosed a standard fuel tank having a mounting access pan 1 on which is mounted by suitable fasteners 2 at diverse points a housing 3 in which the pump is housed as a unit. The unit comprises a high pressure air driven turbine 4 secured to the lower portion of a main drive shaft 5 which is connected at its upper end by a gear train 6 to a secondary or centrifugal drive shaft 7. The latter serves to drive suitable centrifugal means to pump fuel from the tank through various stages as indicated by the path of the arrows. The fuel pressure increases with each stage, and is finally passed to a main pump stage associated with the main drive shaft from where it is driven at a high pressure through an outlet 8 for utilization by the engine.

The turbine 4 which drives the main drive shaft is housed in a chamber 9 of the housing and is sealed off from the rest of the unit by a housing partition wall 11 at its top and by a surrounding wall 12. The chamber is closed over at its bottom by a housing block 13. The chamber is provided with an inlet opening 14 adapted for connection with a suitable source of high pressure air. The bottom block 13 is provided with outlet orifices 15 which communicate with a further and enlarged opening 16 adapted for connection with an outlet tube for carrying off air used in driving the turbine.

The turbine comprises a first impeller stage 17 and a second impeller stage 18, both axially mounted fast upon the main drive shaft 5. Positioned between the two turbine stages is an intermediate turbine nozzle block 19 which is secured fast to the housing wall by suitablefastening means 20. The air inlet opening communicates with the first turbine stage through a nozzle block 21.

High pressure air is admitted to the turbine chamber through the nozzle block 21 where it attacks the first turbine stage 17 and then passes through the intermediate nozzle block 19, to attack the second turbine stage 18, whereupon the turbine and its associated drive shaft are caused to be driven at a high velocity in accordance with the pressure of the air at the intake opening. The course 2,785,635 Patented Mar. 19, 1957 2 of the air from the inlet 14 to the outlet 16 is indicated by the path of the arrow.

The main drive shaft is suitably mounted at its ends for rotation in proper bearing blocks 22. A suitable bearing cooling fan 23 carried on the main drive shaft cools the bearings at the lower end of the shaft.

Rotation of the main drive shaft 5 drives the connected gear train 6 at its upper end. The gear train is housed in a chamber or box 24 suitably sealed off from the rest of the unit by partitioning portions 25 of the housing. The gear "box is provided with a suitable cover 26 adapted for removal to allow access to the gear train.

The motion of the main drive shaft is communicated through the gear train to drive the pump drive shaft 7. The latter is mounted for rotation at its upper end in bearings of a block 27 carried in the housing element 25. The drive shaft extends down into. the housing unit through a series of chambers connected by passage to one another. At the bottom of the housing is a separation chamber 28, adapted to take in fuel from the tank 1 and provided with an annular cavity-like portion 31. A separation centrifugal pump unit 32 bolted fast to the end of the pump shaft 7 divides the separation chamber 28 into an upper and lower part. The separator is formed for the purpose of separating dissolved air andfuel vapors from the fuel, and to drive the separated fuel to a first booster stage. To this end the separator includes fan vanes 33 in its upper portion and fins 34 about its rim. As the pump shaft carries the separator about, the dissolved air and vapors from fuel taken into the separation chamber from the tank are forced upward above the separator into the chamber 30 from where they are discharged by the fan through a vent 35. Fuel is centrifugally thrown from the separator chamber into the cavity 31 from where it is fed by the pump through a connecting passage 29 to an upper enlarged annular chamber 35. This chamber is partitioned off from the discharge chamber below by a housing rib section 36. A hub 34' of the pump shaft passes through the partition wall 36, and where it is provided with a suitable bearing seal 37.

A first centrifugal impeller 38 representing the first booster stage is carried on the pump shaft 7. It is arranged so that its blades pick up the fuel fed to the chamber 35' and drive it forcefully through diffuser elements 39 to a more confined chamber space 41 above the impeller. From here, the fuel is picked up by a second centrifugal impeller 42 representing the second booster stage, and is forcefully driven into a further and larger annular chamber space 43. The fuel collects in the latter chamber and is forced at increased pressure through a housing passage 44 to a smaller chamber space 45 surrounding the main drive shaft. From chamber 45 the fuel is driven by a final centrifugal impeller 46, carried on the main drive shaft 5, through the outlet opening 8 at a further increased pressure. Fuel burning devices, not shown, are adapted to utilize the fuel passing through the pump outlet 8. The course of the fuel is indicated by the path of the arrow.

Suitable fuel sealing means is provided at 47 at the upper end of the common pump shaft7 to prevent fuel escape along the shaft to the gear box. Similar sealing means 48 is also provided at the upper end of the main drive shaft, as well as at the point separating the turbine chamber from the main pump impeller chamber.

The gear train 6 is arranged to drive the pump shaft 7 at a low speed as compared to the speed of the main drive shaft, and at a ratio of about one to eight. Air is admitted through inlet 14 at a pressure sufficient to drive the main drive shaft at about 24,000 R. P. M., and the pump shaft at about 3,000 R. P. M. Fuel is pumped out of the outlet at a pressure of about 490 p. s. i. g.

and described, .but also 1112311 forms as may be reasonably construed to be within the spirit of the invention and scope of the appended claims.

Whatis claimed .is:

1. ,An air driven fuel-pump system of the character set forth, useful in supplying fuel at .a proper pressure to fuel .burriingdevices of a jet engine, comprisingin combina tion ,in a housing unit a succession of connected centrifugal pump stages including an initial centrifugal pump fuel and vaporseparator stage arranged for separating vapors from the fueland pumping the separated fuel to thesucceeding stages a drive-shaft common to the several .mentionedpump stages and vapor separator stage, a final centrifugal pump stage arranged to pump through a utilization outlet fuel delivered to it from the last of the succession of centrifugal pump stages, air driven turbine means arranged .to drive the final pump stage a main drive shaft common to the turbine means and the final pump stage, .and gearing operatively connecting for a relatively lower speed of operation the succession of pump stages 'withthe final pump stage, bearings supporting the main shaft and fan means carried by the latter for cooling the bearings.

2. In a system as in claim 1, wherein the gearing is characterized as a gear train and is housed in a boxhaving a removable access cover, and which box is sealed against fuel seepage to it from the dififerent pump stages.

3. In a system as in claim 1, which is characterized as a two-stage air driven turbine comprising a first turbine drive impeller and a second turbine drive impeller and wherein the housing of the turbine is arranged to utilize high pressure air from a single source to drive both stages.

4. in a system as in claim 1, wherein the air driven turbine means is of the two-stage type and is contained in a chamber sealed ofi. from the rest of the unit and the chamber is provided with a single intake opening adapted for connection to a high pressure air supply and the chamber is provided with an outlet for carrying away used air.

References Cited in the file of this patent UNlT-ED STATES PATENTS 706,187 Lindmark Aug. 5, 1902 2,492,672 Wood Dec. 27, 1949 2,513,992 Burns July 4, 1950 FOREIGN PATENTS 22,194 Great Britain Nov. 7, 1899 26,821 Great Britain Nov. 18, 1910 Winn

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