US910170A

US910170A - Elastic-fluid turbine.

Info

Publication number: US910170A
Application number: US39396307A
Authority: US
Inventors: John G Callan
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1907-09-21
Filing date: 1907-09-21
Publication date: 1909-01-19
Anticipated expiration: 1926-01-19

Description

J. G GALLAN.

ELASTIC FLUID TURBINE.

APPLIOATION FILED saw. 21, 1907.

Patented Jan. 19, 1909.

/z 7 vent/or: John G.Ca//an 14 12, messes:

UNITED STATE PATENT OFFICE.

JOHN G. CALLAN, OF NAHANT, MASSACHUSETTS, ASSIGNOR TO (rl'INERA l. El .ECTR ll COMPANY.

' l A CORPORATION OF NEW YORK.

ELASTIC-FLUID TURBINE.

Specification of Letters Patent.

Application filed September 21. 1907.

Patented Jan. 19, 1909.

Serial No. 393,963.

To all whom it my concern:

Be it known that I, JOHN G. CALLAN, a citizen of the United States, residing at Nahant, county of Essex, State .of Massachusetts, have invented certain new and useful Improvements in Elastic-Fluid Turbines, of which the following is a specification.

Turbines having independent and oppositely rotating wheels to the buckets of one of which all of the steam or other motive fluid is delivered by suitable nozzles to flow in series through the wheels without reversal of its direction have certain advantages when combined with electric generators in that the combination is highly efiicient,- and electric generators of the types and sizes best fitted for the work can be employed. There is one disadvantage however in such constructions for certain kinds of service, 2'. 6., that one wheel will do about seventy per cent. of the work and the other about thirty per cent. This I overcome causing the wheels to do equal work by the use of nozzles for both wheels arranged to discharge a region or zone concentric with the axis and in opposite directions.

In order to obtain the highest elliciency, the entrance angle of the buckets receiving steam from the nozzles must bear a certain definite relation to the spouting velocity of the steamand the bucket speed. The discharge angle must also hear a certain definite relation to the velocity of the fluid stream and the bucket speed. This means that the discharge angles of a given row of wheel buckets are such that they will not properly serve as entrance angles for steam going the other way owing to the loss of velocity as energy is imparted to the wheel. To oven come this I employ intermediate buckets of such shape that they will receive fluid at Whatever angle it issues from one row of buckets and discharge it at the proper angle and velocity against the adjacent buckets on the other wheel. With such a construction the intermediates do not reverse the direction of flow of the steam as they do in common constructions, but serve only to guide it so that the proper angular relation is preserved a d so that wheels having similar bucket an lcs may be employed, and this with wheels which rotate in opposite directions. 'lghe nozzles located on opposite sides of themh eels are offset so that the fluid jets will notinterfere, and "the intermediates'are similarly offset, each set of intermediates being arranged to receive all the steam discharged by its coiiperating nozzle. \Vhen nozzles are employed which discharge fluid in opposite directions in the manner stated, the intermediates cooperating with the nozzle or nozzles on one side are revcrsely dis posed with respect to those on the other side.

The general arrangement of nozzles, buck-- ets and intermediates also such that the entrance angle of the buckets receiving steam from the nozzles serves in an eilicient manner as the discharge angle for the steam coming in the opposite direction.

It sometimes happens with turbines having oppositely rotating wheels that it is desirable to use very high bucket speeds. constructions result in hubs for the wheels that are so long in the axial dimension that the buckets cannot be placed close enough together to permit the fluid to flow fronrone to the other without excessive leakage. In such cases I place my improved form of inter Such I mediate buckets between the rows of wheel zles discharging in opposite directions; Fig.

2 is a diagrammatic view of the some showing the relation of the nozzles. wheels and intermediate buckets; and Fig. is a section of the rims of the wheels and the int'erinedi ates showing the relation of the nozzles thereto.

1 indicates the casing of the turbine which may be divided in any suitable manner to give success to the interior. It is provided with inlets 2 and 3 which communicate with steam chests 4 and It is also provided with conduits 6 and 7 through which steam or other elastic fluid may be discharged to the atmosphere or to a condenser. Mounted within the casing are oppositely rotating bucket wheels 8 and 9 having symmetrical peripheral buckets. it is to be noted that the bucket-s have the maximum height required to accommodate the steam at the exit; this is necessary because the entrance for one nozzle is the exit for the other. Each of these wheels is provided with an individual shaft and overhangs its bearing (not shown). Where the shaft projects through the casing a suitable packing 11 is provided to prevent the escape 'of steam orthe entrance of'air. Located between the wheels are intermediate buckets 12. In the present instance these buckets are formed in' a ring '13 that consti- .tutes a part of a wheel casing but other arrangements may be employed. Steam is ad mitted to the first wheel by steam chest 4 through a sectionalized nozzle 14, from which it passes through the wheel 8, and

after being guided and directed by the walls of the intermediate it is discharged against the buckets of wheel 9, and exhausts through the orifice 1,5 communicating with the exhaust conduit 6. On the other'side of the wheels and diametrically opposite the nozzle 14: for the purpose of illustration is a sectionalized-nozzle 16 for discharging fluid in.

an axial direction opposite to that discharged by the nozzle 14.. The steam then passes through the intermediate buckets 17 and mediates 12 are so shaped that the virtual buckets is therefore the same.

angle of the steam leaving them will be the same, or substantially the'same, as the en trance anglesof the buckets 'on'w-heel 9. In calculating the angle of entrance of these bucketsthe velocity of the moving steam and the speed of the bucket must be taken into consideration. They are so designed as to receive the emergent steam from one wheel with the minimum steam shock and deliver to the other Wheel in the same manner. These conditions are fulfilled when the mean direction of the steam'jet is coincident with a tangent 'to the entering edge of the receiving buckets whether they be the stationary buckets of the intermediates or the moving buckets of the wheels. As shown the virtualangle of the steam issuing from th intermediates is 25 and the entrance angle of the .The actual discharge angle of the nozzleis 16, and the actual entrance angle is 33. The intermediates 17 cooperating with the nozzle 16 are oppositely disposedwith respect to the intermediates 12 and receive steam from the righthand wheel 9 and' direct it in the opposite direction against the buckets on wheel 8 in such a manner that the virtual angle of the fluid is 25. I'have mentioned the angle of 25" as a specific embodiment of my invention but do not wish to be understood as limiting myself thereto as chan es in velocity of'the fluid or the bucket speec l will require changes in the bucket angles. The passages of the intermediates are so proportioned that the fluid discharged into their inlet ends at a velocity less than the velocity of discharge from the nozzles is delivered from'the exit ends of said passages at substantially the nozzle discharge velocity.

In Fig. 3 is shown the preferred arrangement of the nozzles and buckets. In this figure the radial height of the buckets is considerably greater than that of the nozzles. This is made necessary by'the factthat each row of wheel buckets acts as a primary wheel and as a secondary, and thearea of the I bucket spaces must be great enough to convey the fluid without choking. To state the matter in another way the radial height of the wheel buckets is determined not by that of the adjacent nozzle as is usually the case but by the volume of steam passing throu 'h them and received from the nozzle or nozz es adjacent the opposite wheel.

By reason of my improved construction I am enabled to make a turbine wherein the steam acts with full efficiency on the buckets and' both wheels can be made to perform equal amounts of work, instead of unequal amounts as would be the case if only one wheel received steam directly from the nozzle or nozzles. The use of the intermediates insures the proper relation betwee" the virtual angle of the steam and the actual angle of the buckets. I prefer to make the intermediate buckets as short as possible so as to reduce the friction to a minimum. It is to be noted that thesintcrn'lediates do not reverse the direction of steam as is the case with the intermediates ordinarily employed, and since they do not reverse the direction of the steam the losses due to friction, compression and eddies is not as great as with prior constructions. By using the, oppositely rotating wheels and driving independent electric generators electrically geared together, the advantages of high bucket speeds are obtained without unduly high shaft speeds. It is evident that by slightly changing the shape of the intermediate buckets I can distribute the work unevenly between the two wheels if such distribution be desired for any reason. If the speeds at which the turbine is to be run require for mechanical strength wheels havinghubs of the type illustrated in Fig. 1 it is evident that without the intermediates the steam could not be efi'ectually conducted;

with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an elastic fluid turbine, the combination of a casing, bucket wheels mounted therein, curved intermediate buckets which receive motive fluid at fuch an angle from a Wheel revolving in one direction and discharge it without reversal at such an angle against the buckets of the adjacent wheel that the mean direction of the stream of fluid is tangent to the entering edge of the intermediate buckets and of the wheel buckets against which it is discharged to cause said wheel to revolve inthe opposite direction, a device admitting fluid to one of the wheels, and a similar device admitting-fluid to the adjacent wheel inthe oppositr direction.

2. In an elastic fluid turbine, the combination of a casing, a bucket wheel mounted therein, a shaft for the wheel, a second bucket wheel also mounted in the casing, a shaft for the second Wheel that is independent of the first, intermediate buckets supported by the casing and so curved that they receive motive fluid from one wheel and discharge it against the other at such angles that the mean direction of the stream of fluid is tangent to the entering edge: of the intermediate buckets and of the wheel buckets against which it is discharged, a device for discharging fluid from a source of supply against one of the wheels, and a similar device for discharging fluid against the other wheel in the opposite direction.

3. In an elastic fluid turbine, the combination of a casing, oppositely rotating bucket wheels mounted therein, simultaneously operating curved intermediate buckets common to the wheels and arranged in sets between them, one set discharging fluid in one direction and the other set in the opposite direction, and devices receiving, fluid from a source of supply and located on opposite sides of the wheels which discharge located on opposite sides of thewheels which discharge fluid in opposite directions in a region or zone concentric with the axis and cooperate with the sets of intermediates to cause rotation of the wheels.

5. In an elastic fluid turbine, the co1nbi-- nation of a casing, oppositely rotating wheels mounted therein and having similar receiving and dischar e angles, nozzles located on opposite sides of the wheels and having similar-discharge angles, and intermediate buckets arranged in sets between the wheels one set being reversely curved with respect to another set, the said sets modifying the direction of flow of the fluid without reversing it.

6. In an elastic fluid turbine, the combination of a casing, oppositely rotating wheels mounted therein'having rims provided with buckets, elongated hubs which project beyond the side of the rims and cause the wheels to be spaced apart, and webs between the hubs and rims, nozzles arranged ,on op: posite outer sides of the wheels to deliver motive fluid thereto, and intermediate buckets arranged in sets in the space between the wheel rims to modify the direction of flow of the fluid without reversing said direction, the buckets of one set'being reversely curved with respect to those of another.

In witness whereof, I have hereunto set my hand this thirteenth day of Sept, 1907.

JOHN G. CALTiAN.

WVit-nesses JOHN A. MoMANUs, J12, ALvAnAuo L. R. ELLIS.