US1089710A - Low-pressure steam-turbine. - Google Patents

Description

' 0. JUNGGREN.

Low PRESSURE STEAM TUBBINB.

APPLICATION IILEI) DGT. 21, 1912.

1,089,71 0. Patented Mar. 10, 1914 Witnesses: Inventor:

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OSCAR JUNGG'REN,`"OE SCHENECTADY, NEW YORK, ASSIGNOR 4'JI'O GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

LOWPRESSURE STEAM-TURBINE.

Specification of Letters Patent.

Application filed Detober 21, 1912. Serial No. 726,867.

To all whom t may concern of New York, have invented certain new and useful Improvements in Low-Pressure Steam-Turbines, of whichthe following is about 50,000 cubic feet,

a specification-- y This invention 'relates to low-pressure elastic. fluid turbines, and .its object is to provide for an economical and eilicient utilization of the steam when large quanti-` ties are used and expanded down to a very low absolute pressure.

The source from which the low pressure steam is derived is unimportant. It may be the lexhaust from a high pressure turbine or from a reciprocating engine, or it may be derived from a heating plant or Some other industrial system iny which a large quantity of steam is required; or from a combinltion of any two or more of these sources.

My invention contemplates the utilization 'of say two hundred thousand pounds ozt' steam per hour, taking it from its source at or near atmospheric pressure and extracting from it practically all ot its energy. The volume of a given weight of steam at low pressures is very great. One pound of water evaporated into steam at 215 pounds gage pressure occupies about 123 cubic feet. Expanded down to Q2 inches vacuum it fills about 5800 cubic feet or 4:7 times its volume at 215 pounds. At 26 inches of vacuum it has nearly doubled, being about 11,000 cubic feet, while at 29.1 inches vacuum, that is, at about .4 pounds absolute pressure it fills or some li013 times its yvolume at 215 pounds. r It is therefore evident that when a high vacuum can be ob ltained,the lower stages of the turbine must have enormous capacity to accommodate the vastly increased bulk of steam. Attempts have been made 'to meet' this situation by dividing the low pressure steam between two similar stages, usually 'so arranged that the steam flows in opposite directions through said stages, in order to balance the thrust on the shaft. But the ordinary divided tlow turbine is incapable of handling the big volumeyof steam in the higher portions of a good vacuum unless it is operated at very high speed, and the object of my invention is to provide for a safe utilization of large amounts of low pressure steam without unduly enlarging the diameter of the turbine, or the lengthof the buckets, or operatlng the machine atdangerous speeds. Enlargement of the turbine would be expensive not only in cost of manufacture but also in the matter of space in the power station, while undulylong buckets or abnormally high speeds would also entail costly t Patented Mar. 10,1914.

construction as well as serious problems of operation and maintenance. I solve the dificulty in what may seem to be a simple manner, but one which, so far as I am aware, is novel. After leading the low pressure steam throu h the first few stages of a divided flow tur ine, it is' directed at each end of such turbine against bucket wheels operating in parallel, so that without any excessive increase in the diametery of said wheels, or unwieldly lengthening of the buckets, the available bucket area is doubled in that stage. In effect it amounts t'o another' division of each subdivision of the divided {low turbine, so that during the concluding portions of its passage the steam has four parallel paths in place of two.

'lhe accompanying drawing is a somewhat diagraminatic illustration of a turbine embodying my invention.

The machine illustrated is of the Curtis type, and has a horizontal shaft l journaled' in pillowblocks 2 at the ends of the casing 3. Low pressure steam is supplied to said casing from any suitable source; such asehigh pressure stages operatingcn the same shaft 1, a high pressure reciprocating engine, or any other machine or apparatus from which high pressure steam exhausts at a comparatively low gage pressure. This steam is delivered to the chamber 4t in the casing 3, from which it llows through oppositelyfacing nozzles 5 .to two bucket wheels (3, 6 mounted on the shaft 1. From cach bucket wheel the steam proceeds through a plurality of stages 7, I .whose number may be varied to suit the requirements of any particular case. By the time the steam arrives at stages 8, 8 it has expanded to such a. point that I find it economical to subdivide it again. Accordingly it passes not only to the nozzles 0, 0 but also flows through passages 10, 10 which lead to nozzles 11, l1 opposite to the nozzles 9, 9', so that in this concluding portion of its flow the steam is directed against bucket wheels 12, 13, 12',

13 operating in parallel. In connection 110 located in housings formed by the dividing with this arrangement it will be noted that the nal stages12, 13, and 12 and 13 are Walls 15, 15f the top, sides" and ends of the casing 3, and the caps 16, 15` the flow of steam being restricted and diverted into.l

the outernozzles 11 and 11 by the annular rings 17,117. The passages 10 and 10 are thus continuous around the periphery ot the bucket wheels 12, 13, and 12', 13', and are interrupted only at the base Where the final stages exhaust into the condenser outlets 14 and 1t. By this arrangement substantially equal quantities of steam are fed to each Sidejbf the divided iinal stages and a much larger quantity of steam can be lian-- dled by a given size of bucket Wheel. Considered from another view point, I divide my turbine casing into three compartments, the central compartment 1 being a closed continuous annular chamber, While the compartments 10 and 10 are continuous annular chambers except Wherev interrupted .by the openings leading to the outlets 14: and 14e. This arrangement is equivalent to doubling the length of the blades on wheels 12, 12',

but is greatly superior to such a construc tion, not only in economy of space and simplicity of manufacture,'but also in operation and maintenance: for example, by reason of reduced strains on the buckets. Fromthe wheels 12, 13, 12, 13 the steam passes to the outlets 14, 14 leading to the condenser, in.which a high vacuum is"'main tained. This machine will vhandle Very' large quantities of steam at the vast volume due to `-the invention can be carried out by lother means.

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

1. A low pressure turbine comprising a casing'divided into a middle and two outer compartments, tivo sets of bucket wheels in said middle compartment arranged to form steam tosaid middle compartment.

successive stages of' a divided How turbine 55 and hav-*ing'their final stages communicating with said outer compartments,l a plurality of bucket wheels in each of the outer coinpartments arranged in parallel as regards the How of steam, and means for admitting 2. A low pressure turbine comprising a.

casing divided into a middle and two outer compartments, two sets of bucket wheels 'in said middle compartment arranged to forni successive stages of a divided flow turbine' and having their final' stages communicating with said outer compartments, two bucket wheels located in eachof said outer compartments, oppositely facing nozzles fordi- -recting steamto said last named bucket Wheels and means for admitting steam to said middle compartment.

3. A lov1 pressure turbine comprising a casing divided into a middle and twol outer compartments, two sets of bucket wheels in said middle compartment arranged to form successive stages of a divided flow turbine' and having. their nal'stages communicating with said outer compartment, a pluralityd of bucket wheels in each oft-he outer com-` partments arranged in parallel, means for admitting' steam to said middle compart-v mentand exhaust -outlets coinniunrcating Withfeach of said outer compartments- 4. A .low pressure turbine comprising a casing, a shaft extending longitudinally of said casing, aplurality of bucket wheels carried by the central portion of said shaft,- dividing walls forming a central annular steam chamber` entirely surrounding said bucket Wheels, nozzles carried vby saidl dividing walls and coperating with said bucket wheels to formsuccessive stages of a divided flow turbine, the iinal stages exhausting intov the spaces between each dividing walland the end of thecasing, a plurality of bucket Wheels arranged in parallel as regards the lowof steam located in said spaces, and an outlet communicating spaces to receive the exv with each of said4 haust my hand this 18th`day of'October, 1912.

. OSCAR JUNGGREN.

Witnesses BENJAMIN B. HULL, HELEN ORFORD.

4Copiers of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents.

Washington, 19.0.

In witness whereof, I have hereunto set'

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