US1300287A - Marine steam-turbine. - Google Patents

Description

1. F FME T TEN; MARINE SIEAM- TURBINE. APPLICATION HLED SEPT. 9. 1915.

Patented Apr. 15,1919.

630M itd z,

A TTORNEYJ,

' excess 7 or reaction blades.-

this type of turbine JOHN F. inn'rrnmonPHILADELP IA, rnnnsvnynifin, .Assmnon'ro 'rnn ILLIAM cam]? 85501 15 snxr a-n'njemn BUILDIN sYLvAnre.

o'o'MrANY, a conronn'rion or PENN- MARINE instream.

To all whom it may concern; r i

Be it known that 1, JOHN F. Merrnn, a citizen of the United States, resldmgat Philadelphia, in the county of Philadelphia nd State of Pennsy1vania,have invented certain new and useful .Improvements in Marine Steam-Turbines, of which the following is a full, clear, and exact specification.

This invention relates to turbines for driving a propeller shaft, and,

has for its-object to increase the. overall efliciency as compared w th constructions previously used.- The invention has 'pan ticular reference to turbines compose'dpf,

several wheel or c0mp011ndjvel0cityi stages followed by a solid headed drumjcarrymg' a'number of single rows ofeither impulse the wheel or compound velocity stages .to the least possible number, 4

many blades as possible onrthe drum bee cause the drum is "the more etficient pa-rt of the 'turbine. In marine turbine installations, where the propeller" isdife cftlyhcoupled to the turbine shaft, it has-been; customary to cause the pressure ontheheadof the drum to be aboutiequal ;to or slightly in of the propeller thrust, in order" to save wear on the thrust blocksi In some instances, a part of'lthis thrust hasbeen pro:

duced by the reactionbladingon the drum,

but where impulse blading is"used the entire thrust opposing the propeller has been exerted by the drum. As the diameter of the drum stages, whether of the reaction or of the impulse type, i determined by the blade speed, the steam volume, etc, it has beenthe common practice to carry the expansion of the steam in the wheel stages before admitting it to the drum stages farther than is desired for the best overall economy, since the drum stages are alway of better elliciency than the wheel stages. One reason for doing this has been in order tosecure the requisite low steam pressure,onthe head of the drum so as not to produce a backward thrust too much in excess of the forward propeller thrust.

According to the present invention, a marine steam turbine is provided in which the relatively inefficient wheel stages are re- 'tained at or about equal to the forward pro marine steam 1 a In he specificel bo ime fr e The best i efficiency of depends upon reducing f and carrying as, p p

total, rearward pressure jexertedbythe main drai 'by the necessity advantages ofthis construction, that. of increased overall economy,jarethat i tice; but is only subjected to thesamerean ward pressure as thatapplicd-zto the auxiltotal steam pressure on "the.

.the first stage and will run cooler.

, and a rearward bearingnot shown,-in the Specification a Letters Patent. Patented Apr, 15, 191 9., Application filed September-9,1915. Serial No. 49,661." 5

higher than has heretofore been employed, 'whlle at thesame time enabling the backward thrust, onthe drum head to be main p'eller thrust. Thereby, a large number of relatively inefiicient wheel stages can be rep'lacedby "relatively 'efiicifent drum stages workmg'at the samezpressure, s0 that the ov ra efficiency, oflthe plant is very much. 1ncreas --fv '65 tion herein shown, one of the forward wheels; preferably the initial one, is,pro

'yided with a smalldrum, oneside' of. said drum being subjected to steam pressure led from one, oftheelower stages, for example,

from 1 drym'staganndthe other side i of the, drum being a subjected to the; steam a pressureion the rear*of the first wheel. ,jfThe v in opposition *to the propeller thrust 15 thus reduced, so that the number of a drum stage iwhiehcan beemployedis not liinited 1] of eoordinatinggthje drum 1 pressure to the propellerthrust; Further" the forward gland ofi'the turbineisnot sub- 1 jected to the initial'high' steam pressure "in the-first 'wheel stage, as isthe usual prac iary drum. The gland is thus simpler: in constructiomand easier to keep in order. Also,. the forward bearing is; farther reg moved from the. high temperature steam in The head of the turbine casing is also subjected to less total pressure, and consequently has less tendency to deflection.

In the accompanying drawing, .1 represents a turbine caslng in which a propeller shaft" 2. i ournaled in forwardbearing 3,

usual manner. lrepresents a propeller'carried by shaft 2. 5 represents the forwardgland, which is ordinarily subjected -to the same pressure as that admitted to theJfi-rst stage, ,Mounted on the shaft 2 'are' one or more high'pressure wheels 6, and rearwardly 105 thereOf is'a drum ,7 having forwardhead 8.

other than The wheels 6 have passages through them to equalize the pressure on the oppositefaces ofztheir webs and 9 are diaphragms carryingnozzles l0iofany desired construction, and separating'the several wheel stages. The forward nozzles 10 are supplied with high pressure steam by a belt 11. The sev eral wheel stages are provided with fixed and moving blades of any usual construction, but preferably the blades are of the impulsetype. The drum 7 is also provided moving blades, which may be eitherof the impulse or of the reaction type, or partly of both.

Mounted on the forward side of the first wheel 6 is a ring 13, which cooperates with a; concentric ring 14 carried by the casing to form a steam tight joint. Ordinary gland packin'g'rings may be used for this purpose. The chamber 16 therebyformed is connected by pipe 17 to a'chamber 18 formed in the casing of the drum stages,

and at such a point therein as will provide I .8 tending j peller will be equal tothe total effective area pressure suflicient to reduce the total rearward pressure on the main drum head 8 to the desired amount. V

, The rearward pressure produced'by' drum to oppose the thrust of the proof the drum'8 multiplied by the steam pressure on the forward side thereof, which will considerably exceedthe' forward thrust of the propeller. At the same time, there will V 1 steam pressurefin the fir tiplied by the elfective hey a forward thrust on that portion of the first wheel 6 whichis included within the ring-'13, this thrust being produced by the st wheel stage mularea of this auxiliary drum. By partially or wholly balancing thisffo rce by steam through the pipe .17 from one of the lower drum stages. it

will be seen that the total pressure'of drum 7 Sis reduced so as to balance; the propeller prevents the initial high pressure steamthrust to the desired extent. The'combination of the auxiliary forward drum with the'main drum renders it possible to bring the latter forward into the higher pressure stages of the'turbine toreplace wheel stages, and also to increase the diameter of the drum, without necessitating too great arearward drum thrust. The elimination of wheel stages effects a large saving in the cost of building a turbine, besides increasing the overall efliciency. As will be seen from the drawing, the auxiliary drum chamber communicates with the forward gland, and

from acting thereon. This saves wear and special construction to resisthigh pressure, and also. maintains the forward bearing at alowver running temperature. I f

It will be obvious that the auxiliary forward drum need not be carried by the initial forward wheel, but it is advantageous to put the drum on the forward wheel, rather 'mit the relatively large thrust opposite to turbine, 0r requlre expensive reconstruction of the casing. The pipe 17 can be connected at any point in the drum stages where the desired pressure is found, depending upon the particular installation.

Various modifications and changes may be made in the construction herein illustrated without departing from the scope of the appended claims.

aving thus described my invention, what I declare as new and desire to secure by Letters Patent of the United States is 1. In a steam turbine drive for a ship, the combination with a propeller shaft having a'driving thrust in one direction of a series of steam turbine stages for driving said shaft and mounted on a drum having an axial thrust opposite to the driving thrust of said propeller shaft, a plurality of turbine wheel stages driving said shaft, said drum stages being substantially greater in number than said wheel stages so as to increasethe efficiency of the drive, and means for exertinga counter thrust to counterbalance the excess of said drum thrust and pernumber of drum stages, comprising means for reducing the rearward pressure on one of said wheels.

2. In a steam turbine drive for a ship, the combination with a propeller shaft having a driving'thrustin one direction of a series of 100 steam turbine stages for driving said shaft and mounted on a drum having an axial the driving thrust of said propeller shaft, a plurality of turbine wheel stages driving said shaft, said drum stages being substantially greater in number than said wheel stages so as to increase the efli-' ciency of the drive, and means for exerting a counter thrust to counterbalance the ex cess of said drum thrust and permit the relatively large number of drum stages com-. prising a dummy drum on one of said wheels having an annular steam tight packing engagement with the turbine casing and its interior pressure reduced to increase the pressure on its head in the direction of said propeller thrust.

3. In a steam turbine drive for a ship, the

combination with a propeller shaft having imp; i B

. permit the re1ative1y1ar e number of drum the pressure on its head in the direction of stages comprising.v a we for one of said said pnopellerthrust. q turbine Wheels having a passage time Intestimony' whereof I aflix my ign'ature through to equalize the pressure on each side in presence f w Witnesses- I i of said web and a dummy drum. on one of r JOHN F. METTEN.

said Wheels having an annular steam tight Witnesses:

packing engagement with the turbine easing JOHN H. McMAsTnR, and its interior pressure reduced. to Increase i Isaac H. WRIGHT,

Copies of this patent may be obtained to: five gents each, byf addressing the f'coniminioner or intents,-

Wilmington, D. 0. x

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