US1369023A

US1369023A - Steam-turbine

Info

Publication number: US1369023A
Application number: US106651A
Authority: US
Inventors: Guy Henry Lewis
Original assignee: British Westinghouse Electric and Manufacturing Co Ltd
Current assignee: Metropolitan Vickers Electrical Co Ltd
Priority date: 1916-06-29
Filing date: 1916-06-29
Publication date: 1921-02-22
Anticipated expiration: 1938-02-22

Description

H. L. GUY.

STEAM TURBINE.

APPLICATION FILED 1uNE29, |916.

1,369,023, Patented Feb. 22, 1921.

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'wIT w 5y H. L. GUY.

STEAM TUVRBINE.

APPLICATION F|LD1uNE29,19|6.

Patented Feb. 22, 1921.

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Application To all zio-hora c'mwern.' .'f I *i Be it known thatI, HENRY y n. subject ofthe Kin of GreatBritain, and ak resident of Mano ester, ,n the county. ciw' Lancaster, England, have invented anew and useful Im rovement in Steam-Turbines, of which the ollowing is al specification. In axial flow steam turbines constructed to operate under a high vacuum the length of the moving blades ofthe laststage may' v y.

larged scale on the lilies -III-III and well beas much as two or three times the length of the moving blades of the precedingv stage, and in thecase'of turbines designed to Ahave a large output considerable practical diiculties 'are experienced in providing moving bladesfor the last stage ofl such a len h. y c

o overcome these diiiiculties it has been proposed toconstruct the last stage of the turbine as a double stage in which the steam is divided into two annular portions or belts and flows in substantially .the same direction through two separate rows of moving blades. The present invention has for its object to provide a turbine having a last stage of improved construction through which the flow of steam takes place in the above described 'According to this invention, of the two annular. portions into which the steaii'rleaving thepenultimate stage of the turbine is vdivided the outer portion flows through an the latter the steam passes outwardly through a plurality of transverse passage- Ways contrived in the above mentioned annular chamber to the exhaust casing of the turbine.

With the construction above described each of the annular portions into which the steam leaving the penultimatestage isp'divided is caused to act on a separate ringof moving blades without any substantialoccurring. x The .invention is applicable to turbines of either the impulse or reaction-type and of struction.

mi mann'imrnnine couranxbnnnman; .a COMPANY or either,

- .'iratted a2. 419,21, v

, n isk or drum construction and will now'begdescribed in greater detail with ref erenceto the accompan ing drawings which f show, byway'of examp e, an impulse turbine ,of` disk construction to which the invention is applied-.v Figure 1 is a vertical longitidinalsection of a portion of the low pressure stages'of the turbine, and Fi 2 is'a 1 transverse section taken on the line K -II of Fig. l, Figs. 3 and4 are sections on an en'- 'the high pressure portion, to -which the present invention does Anot apply, is indicated at 5 and may -be of any desired type and con- In the low pressure portion,- shown in section, the turbine shaft is indicated at 6 supported in a bearing or bearings 7 as usual. 8 is the exhaust casing and 9 the exhaust outlet leading to the condenser. Mounted -on disks 1U, 11 on the shaft arerows of moving

blades

12, 13 respectively between which is a coperating row of stationary 'guide blades 14. The steam leaving the row of moving' blades 13 is divided into two annular portions or beltsby a circumferential rim or wall 15 forming part of the stationary diaphragm 16 which is provided with

guide blades

18, 19 of an usual and well known construction. A dis 20on the vshaft 6 carries a row of moving blades 21, through which the steam passing through the

stationary guide blades

18, 19 iows. An annular steam conduit member 22 supported in the exhaust casing 8 by a web or diaphragm 23 conducts the outer portion of steam leaving the moving blades 13 to a row of stationary blades 24 secured in the end of the steam chamber 22. A row of moving blades 25 attached to a disk 26 mounted on the shaft 6'coperates with the stationary guide blades 24 and through -which the steam leavin said stationary blades passes. A plura ity of transverse passageways 27 (see Figs. 2 and 3) extend through the conduit member 22 whereby steam-'leaving the blades 21 passes outwardly'iitosthe exhaust casing.

In :o eration the steam havin l d p change in the direction of flow of the steam p g Passe through said blad throii'ghthe high pressure portion of the nular portions by the circumferential wall Areaction or other formo constructional details of the turbine varied 24 and thence through the row of moving.

blades 25 direct into the exhaust casing 8 of the turbine.

The low pressure part of the turbine illustrated in the accompanying drawings lis shown as being of the impulse variety and consequently the major part of the expansion of the steam passing through the blading takes place in the

stationaryguide blades

14, 18, 19 and 24. as is usual, but 1t is to be understood that thev accompanying drawings are typical of one form which the invention may take when applied to an impulse turbine, as the invention ma be applled to a turbine and the from what is shown, without departing from the spirit and scope of the invention.

It will be obvious that my improvement is in a divided-flow, low-pressure turbine section whereby the low-pressure steam maybe eiiiciently used. The divided-flow, low-pressure section includes a stage having the

blades

12, 18, 14 and a lurality of sets of 'low-pressure blading. he wall element 15 serves to divide the steam discharged from the stage comprising the

blades

12, 13 and 14 into inner and outer annular portions, the inner annular portion being utilized by the nearer low-pressure blading and the outer annular portion passing through an annular conduit member 22 around theloW-pressure blading referred to and being utilized by other low-pressure blading arranged farther along the turbine axis.

Furthermore, in the drawings the inner and outer annular portions into which the steam leaving the moving blades 13 is 'divided, have been shown as flowing respectively through one row ofv stationary and moving blades only. Itis to be understood, however, that the invention is not limited in this respect and that if desired the inner and outer portions of steam may each iiow through two or more rows of stationary and moving blades if desired before passing vinto the exhaust.

I claim as my invention:

1. In a turbine, a divided-flow, low-pressure section comprising a stage, means to divide the steam discharged from said stage into inner and outer portions, low-pressure blading receiving the inner portion of steam, other lowressure blading, and a conduit member ildr conducting the outer portion of steam to said'otl.\ low-pressure Hblading.

2. In a turbine, a divided-flow, low-pressure section-comprising a stage, mea-11s to divide the steam discharged from said stage into inner and outer annular portions, sets oflow-pressure blading arranged along the turbine 'axis after said stage, means to conduct the'inner annular portion of steam to the nearer low-pressure blading, and a conduit member-serving to conduct the outer annular portion of steamto the farther lowf pressure blading.

3. In a turbine, a divided-How, low-pressure section comprising a stage, means to divide the steam discharged from the Stage into inner and outer portions, low-pressure blading receiving the inner portion of steam, other low-pressure bladin and a conduit member surrounding the rst-mentioned low-pressure blading for conducting the outer portion of steam to the other lowpressure blading.

4. In a turbine, the combination of an eX- haust casing and a divided-flow, low-pressure section, the latter comprising a stage,

means to divide the steam discharged from said stage into the inner-and outer portions, low-pressure blading receiving the inner portion of steam, other low-pressurey blading, a conduit-member for conducting the outer. portion of'steam to the other lowpressure blading, and passageways extending through the conduit member to afford communication of theirst-mentio'ned lowpressure blading with the exhaust chamber.

5. In a turbine, a divided-How, low-pressure section comprisin a stage, means for dividing the steam dlscharged from said stage into inner and outer annular portions, low-pressure blading .comprising coperating stationary and moving blades receiving the inner annular portion of steam, other low-pressure blading including stationary and moving blades, and an annular conduit member for conducting the outer annular portion of steam to the second-mentioned low-pressure blading.

6. In a turbine, the combination of an exhaust casing and a divided-flow, low-pressure section, the latter comprising a stage, means to divide the steam discharged from said stage into inner and outer annular portions, low-pressure blading receiving the.

inner portion of steam, low-pressure blading for the outer annular portion of steam, anannular lconduit member for conducting the outer annular portion of steam to the second-mentioned bladin means connected to the exhaust casing or supporting 'the conduit member in position, and assage- Ways extending through the conduit member for affording communication of the firstmeshes 1 mentioned 10W-pressure biading with the exhaust casing.

7. In a turbine, the combination of an eX- haust casing and a dividedow, 10W-pres sure section, the latter including a stage, two low-pressure sets of biading7 a conduit member and diaphragm member supported by the exhaust casing at the end adjacent to said stage, a diaphragm carried by the exhaust casing and supporting the other end of the conduit member, a WallA element carried by the first diaphragm and dividing steam discharged into inner and outer annular portions, the inner portion passing to one set of low-pressure biading and the outer portion passing through the annular conduit member to the other set of 10W-pressure blading, and passageways extending through the conduit member to afford ccmmunication between the irst set of 10W- pressure blading and the exhaust casing.

In testimony whereof, have hereunto subscribed my name this thirteenth day of J une, 1916.

HENRY LEWIS GUY. Witnesses:

J. C. BoUTFLoWER, JAS. STEWART BRoADFooT.