US905749A - Elastic-fluid turbine. - Google Patents

Description

. RICE.

ELASTIO FLUID TUBBINE.

APPLIOATION Hum SEPT. 2a, 1904.

Patented Dec. 1, 1908.

3 SHEETS-SHEET 1.

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Incentor Richard H.F?ce g i d' oqttly witnesses R. H. RICE;

ELASTIG FLUID TURBINE.

APPLICATION FILED SEPT. 2a, 1904.

Patented Dec. 1, 1908.

3 SHEETS-SHEET 2.

R. H. RICE.

ELASTIG FLUID TURBINE.

APPLIGATIVON FILED SEPT. 2a, 1904.

Patented Dec. 1,1908.

3 SHEETS-SHEET 3.

InVenLQx'-, Pichard +I. 'Rice Wtrwes M i?? a@ UNITED STATES PATENT OFFICE.

RICHARD H. RICE, OF LYNN, MASSACHUSlETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELASTIC-FLUID TURBINE.

Specification of Letters Patent.

Patented nec. 1, 1908.

Application filed September 23, 1904. Serial No. 225,551.

setts, have invented certain new and usefull Improvements in Elastic-Fluid Turbines, of which the following is a specification.

Elastic fluid turbines of the axial flow impacttype are,for large outputs,provided with wheels of large diameter having peripheral buckets and diaphragms located between the wheels for dividing the casing into compartments or stages. The diaphragms are each made in one piece and are separate from the casing. This means that between the rim of each diaphragm and the casing is a joint which must be'kept tight. When large diaphragms are employed the area of the meeting surfaces is, of course, very considerable. Obviously such a construction involves a good deal of very careful machine work resulting in an increased cost of manufacturing. It also involves a large amount of work to set such a machine up or take it down. In some cases the diaphragms have nozzles formed therein, and when such is the case they are usually only accessible when the entire machine is taken down. It has been proposed in small horizontal machines to make the casing in the form of a long cylinder with diaphragms cast integral with the parts. In this instance, the casing was to be split only in an axial plane. Such a construction is objectionable owing to the warping or distorting thereof when heated. It is furthermore objectionable owing to the fact that no means are provided whereby the removed section can be supported.

Between one stage and the next of the rst mentioned turbines, packings are provided to prevent the leakage of steam or the motive fluid. These packings are supported by complete diaphragms and, as heretofore constructed, are only accessible when the machine is taken down. Such being the case, it follows that the packings will not receive the attention they demand, and as a result the eiiciency of the machine may be seriously impaired. A

The object of the present invention is to overcome the objections above pointed out, and also to improve the construction of turbines in general, as will appear more fully hereinafter.

In carrying out my invention the cylindrical casing is divided in an axial plane into two or more principal sections, each of said sections being provided with one or more partial diaphragms which, when the sections of the casing are assembled, meet and form a wall or walls to divide the casing into stages or wheel compartments. To prevent distortion in casting. or due to heating, to facilitate the manufacture, handling, etc., particularly of the large size machines, each of the main sections is of itself divided into secondary sections, the line of division being preferably in planes at right angles to that of the shaft, each of said secondary sections preferably representing one stage. It will be seen that when the parts of each secondary section are united they form a cylinder, and that in a vertical machine the cylinders are mounted one on top of the other.

The main sections are flanged where they are bolted together and to the end heads, or to the cover and base when the shaft stands in a vertical position. These flanges have broad flat surfaces which can be united so as to be steam tight.

Each secondary section has a part of a diaphragm formed integral therewith. The meeting surfaces of the parts of the diaphragm are faced oli' true, and are provided with means to insure a steam tight joint. It will be seen that instead of having a joint equal in length to the entire circumference of the diaphragm, the joint is'equal in length to the diameter only. Moreover, having plain surfaces the joint can be made tight more easily than where curved surfaces are employed.

Each part of the diaphragm is provided with a seat to receive a packing surrounding the shaft, sleeve or hub carried by said shaft. The packing may be of any suitable construction, it can with advantage be made in two or more segments and suitably united. The object in making the packing in segments is to permit of renewal or adjusting when the parts of the casing are separated. The several secondary sections of the casing are united by bolts, and since they are separable in the same axial plane, it follows that the parts of the casing and diaphragms located on one side of the shaft can be removed or replaced as a unit. The bearings may be and preferably are so arranged that either half of the casing can be removed without seriously disturblng the alinements of the shaft. From this construction it also follows that the diaphragms can be removed or the packings changed or adjusted without disturbing the position of the wheels on the shaft.

It is necessary to make the diaphragms very strong since they are made in separable parts and are subjected to heavy pressures. In order to get the greatest strength with the minimum amount of metal, the diaphragms are cast hollow with heavy radial ribs disposed so as to resist the strains due to the difference in pressure between stages. These ribs also serve to localize the stresses to which the diaphragms are subjected and being inside, the surface of the diaphragm is unbroken. The chambers between the ribs may be directly in communication with each other or not as desired. I find it best to have them in communication with the adjacent stage of lower pressure since any given wall will then be subjected to the dierence in pressure between stao'es rather than to the total pressure. It is aIso advantageous to provide one or more openings or passages for draining the chambers. In a vertical machine the openings are preferably located in the under side of the diaphragm. The cover or head of the machine may be cast hollow with the necessary ribs to give strength.

Another great feature of advantage of my improved construction resides in the fact that one or more complete secondary sections can be added or taken away when it is desired to change the total number of stages. In adding or subtracting stages the nozzles and buckets woulehordinarily be changed to meet the new condltions.

Formed in the diaphragms or carried thereby are nozzles which may be expanding or non-expanding in character, and are preferably although not necessarily, closely associated. I have found, however, in practice that the latter arrangement is best. If all of the metal in the diaphragm adjacent to the nozzle or nozzles is cut away, it would weaken it, and so to guard against this condition heavy ribs are provided adjacentto the bowls or inlet side thereof.

Obviously, the parts of the casing and diaphragme integral therewith are heavy and to remove one of them requires care. In order to facilitate this work a support or platform is provided that is suitably supported, preferably by the metal base of the machine to insure alinement, upon which either part of the casing can be moved. A means may alsobe provided for relieving the part of the casing being removed from the weight of the generator or other apparatus driven thereby.

In the drawings I have shown a vertical shaft machine and while certain features of the invention are of special importance therewith many of them are applicable to horizontal machines.

I have shown a three stage machine, but the invention is applicable to machines having a greater or less number of stages.

In the accompanying drawings which illustrate one embodiment of my invention, Figure 1 is a view in elevation of a turbine of the Curtis type; Fig. 2 is a partial axial section of one of the stages, the section being taken on line 2 2 of Fig. 3; Fig. 3 is a section through one of the stages taken on the line 3-3 of Fig. 2; Fig. 4 is a perspective view showing a half of one of the secondary casing sections, together with its diaphragm; Fig. 5 is a plan view showing the support or carrier for receiving one-half of the casing section when it is desired to expose the interior of the machine, and Figs. 6 and 7 are detail views of a packing.

1 represents the base that is chambered to receive the exhaust, and is connected to a condenser by a suitable conduit. Mounted on top of the base is a cylindrical casing 2 which is divided in an axial plane into two principal parts. These 4parts are provided with ianges 3 and attaching bolts et. Each portion of the casing is made up of a number of secondary sections 5 which are provided with ianges 6 through which pass the retaining bolts 7 and 8. After the secondary sections 5 are secured together it is not the intention to disturb them. WVhen it is desired to expose the interior parts of the turbine the bolts 4, 7 and 8 are removed, after which the half of the casing can be moved along the platform 9 in a radial direction. The platform 9 is supported by suitable means. In the present instance brackets 10 are provided which are bolted to the base 1. Vhen the platform is not in use as a support for a casing section, it can be used as a platform for ordinary purposes.

Mounted on top of the turbine casing is a generator 11 of suitable construction. The revolving element of the generator and of the turbine is mounted on the shaft 12, the latter being supported by step bearing 13 at the bottom and suitable guide hearings 14 at intermediate points. The middle guide bearing is supported by the part carrying the generator instead of by the turbine casing as is usual.

Referring to Fig. 2, 12 represents the shaft of the turbine upon which are mounted wheels 15 each of the latter being provided with one or more rows of buckets 16. Where two or more rows of buckets are provided, intermediate buckets 17 are provided which are situated between the wheel buckets and serve to reverse the direction of the fluid stream in passing from one bucket to the next. The intermediatebuckets are secured in place by bolts 18 which extend through the wall of the casing. The upper and lower ends of the cylinder forming-the secondary sections are provided with flanges which engage with vsimilar flanges on the adjacent sections or with finished surfaces on the cover or base of the machines, as the case may be. Cast integral with the secondary section is a diaphragm 19 which is provided with chambers 2O and radial strengthening ribs between the chambers extending outwardly from the hub. The line of division between the parts of the casing is in an axial plane, and the ribs are so distributed that they coincide substantially with the plane of division and present broad, flat surfaces to insure a steam tight fit. As an additional precaution the parts may be rabbeted together as at 21. The chambers are provided with openings or passages 22, Fig. 3, permitting steam or other elastic fluid to enter the chamber, at the same time acting as drains to carry off the liquid given up by the expanding motive fluid.

Each half of the secondary lsection is or may be provided with nozzles 23 for discharging motive fluid against the adjacent wheel buckets. These nozzles are formed directly in the diaphragm or are bolted thereto and preferably have the same angle of discharge and expand to the same degree. In order to strengthen the diaphragm at the point or points adjacent to the nozzles circumferential ribs 24 are provided. In addition to this, radial ribs 25 are employed which extend over the bowls of the nozzles. In this way the bowls of the nozzles and the nozzles themselves can be equally spaced, at the same time permitting free access of the fiuid thereto.

It will be noted that between the radial ribs there are orifices which communicate with a segmental chamber that is located beneath the ribs. This arrangement has the advantage of equalizing the pressures of the different parts of the more or less subdivided Column of motive fluid vissuing from the preceding bucket wheel. In addition to this it insu-res the proper supply of motive fluid to the bowls of the nozzles. Suitable nozzles are also provided to admit motive fluid to the first stage.

Between one stage and next is a packing 26 of suitable construction to prevent the leakage of motive fluid. I have only shown one packing in the drawing but it is to be understood that all stages are similarly provided. The packing is provided with a cylindrical portion making a close fit with the bore of the hub of the diaphragm and a shoulder which rests on a corresponding shoulder on the diaphragm and is held against the shoulder or seat by the steam pressure in its stage. The packing may as shown have a certain amount of lateral `movement for the purpose of adjustment.

The packing is preferably made up of two or more sections so that it can be removed without disturbing the wheels. Each packing is provided with one or more stops 27 to prevent it from turning with the shaft.

In accordance with the provisions of the patent statutes I describe the principle of operation of my invention together with the apparatus which I now consider to represent the best embodiment thereof, and I desire to have it understood that the apparatus shown is only illustrative and 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 divided into main and sec# ondary sections, and diaphragms cast integral with the secondary sections.

2. In an elastic fluid turbine, the combination of a casing divided into main and secondary sections, the latter being separated in planes at right angles to the shaft, and a divided diaphragm formed integral with each of said secondary sections.

3. In an elastic fluid turbine, the combination of a casing comprising separate divided cylinders placed end to end, and diaphragms which are cast integral with the cylinders for dividing the casing thus formed into stages or compartments, the plane of division of the cylinders and diaphragms coinciding.

el. In an elastic fluid turbine, the combination of a casing comprising cylinders placed end to end, hollow diaphragms cast integral with the cylinders, for dividing the casing into closed wheel chambers, and wheels located within the chambers.

5. In a turbine, the combination of a casing comprising a cylinder divided in an axial plane, one or more divided diaphragms, the parts of said diaphragms being formed integral with the cylinder, and a platform or support for carrying a part of the casing when removed from its normal position.

G. In a turbine, the combination of a casing comprising a plurality of sections placed end to end, each section comprising a divided cylinder, a divided diaphragm for each cylinder section which is cast integral with the parts of the cylinder, a bucket wheel for each of the sections, and devices for discharging motive Huid against the buckets.

7. A turbine casing comprising a divided cylinder, a divided hollow diaphragm, the parts of which are cast integral with the parts of the cylinder, fianges for uniting the parts of the cylinder` and strengthening ribs located within the diaphragm.

8. In a turbine, the combination of a plurality of casing sections, each section being in the form of adivided cylinder, fianges on the cylinders'for uniting them with an adjacent cylinder or part, divided hollow diaphragms cast integral with, and removable with the part-s of' the cylinder, and fiat contacting surfaces between the parts of the diaphragms for preventing leakage.

9. In a turbine, the combination of a casing comprising a divided cylinder, a divided diaphragm formed integral with the parts of the cylinder, bucket wheels located on opposite sides of the diaphragm, a shaft for the wheels, a packing which surrounds the shaft and is carried by the parts of the diaphragm, and a support or platform for sustaining the weight of a section of the cylinder when the parts of the latter are separated.

10. In a turbine, the combination of a casing comprising a divided cylinder, diaphragms for dividing the casing into stages, bucket wheels within the stages, a shaft, and a platform upon which the parts of the casing can be moved to expose the wheels.

11. In a turbine, the combination of a casing comprising a divided cylinder, a divided diaphragm cast integral with the parts of the cylinder for dividing the casing into stages, a base for the machine, and a platform upon which the parts of the casing and diaphragm attached thereto can be moved.

12. In a turbine, the combination of a casing comprising a divided cylinder, diaphragms for dividing the casing into compartments or stages, a base upon which the cylinder is supported, and a platform carried by the base upon which the sections of the casing are adapted to be moved to expose the interior of the casing.

13. In a turbine, the combination of a vertical shaft, wheels mounted thereon, a casing comprising cylinders mounted one above the other, chambered diaphragms cast integral with the casing, and openings or passages in the under side of the diaphragms which admit fluid under pressure to the chambers and also act as drains.

14. In an elastic fluid turbine, the combination of a cylindrical casing which is di vided in an axial plane, a number of divided diaphragms, each formed integral with the parts of the casing, bucket wheels between "below said surface, which receive motive fluid exhausting from the adjacent wheel, a chamber which communicates with the orices, and devices that receive fluid from the chamber and discharge it against a bucket wheel.

17. In an elastic-fluid turbine, the combination of a casing, a partition for dividing the casing into compartments having a flat surface in close proximity to the wheel buckets, ribs on the partition between which are located orifices, the ribs being below the plane of the partitions, a chamber which is formed in the partition below said surface and receives and equalizes the pressure of the fluid received from the orices, and devices which discharge iluid to a bucket wheel and are fed by the chamber.

18. In an elastic-fluid turbine, the combination of a casing, a partition formed integral with the casing for dividing it into compartments having a flat surface in close ,i

proximity to the wheel buckets, ribs formed integral with the partition and separated by orifices, the ribs being below the plane of the partition, a chamber located on the exhaust side of the ribs for receiving fluid from the orifices, wheel buckets, and nozzles receiving fluid from the chamber and supplying it to wheel buckets.

In witness whereof, I have hereunto set my hand this 17th day of September, 1904i.

RICHARD H. RICE. Witnesses:

JOHN A. MCMANUS, J r., O'r'ro F. PnRssoN.

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