US1058936A - Casing for steam-turbines. - Google Patents

Description

P. A. BANOEL. CASING FOE STEAM TURBINES.

APPLICATION YILED APR 18, 1932 Patented Apr. 15, 1913.

WITNESSES o o o IN VE N TOR I ATTORNEY 20 the ;,-,-dueto a; variety of causes. mixed, -,Wlth the hi'gh pressure steamfqlue to UNITED STATES PATENT OFFICE- PAUL A. BANCEL, OF NEW YORK, N. Y.

'ciasnvo r'o'n s'rEAM-TunBINns.

To all whom it May concern Be it known that I, PAUL A. BANCEL, a citizen of the United States of America, re-

- siding in the city, county, and State of New- '5' York, have invented a certain new and useful Improvement in Casing Construction for steam-Turbines of which the following is a true and exactdescription, reference being had to the accompanying drawings, which -.10 form a part thereof.

My present invention relates to steam turbine casings and consists in provisions for preventing the leakage of atmospheric air 1nt0 such a'casing through a oint between 4' 1 stationary parts of thecasing and so located thatthe pressure at the inner edge of the joint is below thatdf'the atmosphere.

- The eiiiciencyof operation of a steam turbine plant depends upon the extent to which ressure of-the steam is reduced as it final y leaves "the rotating element of the V turbine. In the. practical operation of steam turbine plants it is-now common to have the absolutepressure of the exhaust steam leav- 5 ing the turbine as lowas a pound or so. i. a,

.the ressure of theexhaust steam is in the neig borhood of fourteen pounds below the pressure of the atmosphere, and slight de- 1 creases in this low exhaust pressure sul .stantially and markedly increase the chiloiency of operation. To obtain the desirable ":lowexhaustpressure. highly etiirient steam Ucon'densing apparatusis required. he cili- .ciency of the condensingapparatus depends .;in liirgeghreasure upon therate at which air enters thefcondcnser. The presence of air in the condenser is objertionable. not only because itdirectly reduces the vaeuum'olr tainab'le, but also because it reduces the 40 Steam condensing capacity of a. surface coil-- -..denser both by its volume displacement of steam and through its heat insulating prop- .erty. .The' -heat insulatingcapacity of air is such thatin the portionsof a surface con- 5' denser filled-with-sn air and vapor mixture rich in air, the cooling eflectof therondenser ,g-tubes-becomes practical-1 ml. a; "The. presence ofair in the eom'lcu-cr is Some air. is

". itlll presence of-airjn the water supplied to y the steam generating boil ers. Some air may leakinto; the condenser-through the Qconide'nser housing and turbine casing due to the porosity. of the cast.n'on from whichlthese parts areordin'arily made. The bulk of. the

Specification of Letters Patent. Application filed April 18, 1912. Serial No. 691,672.

Patented Apr. 15, 1913.

air entering the condenser, however, leaks into it through thejoints of the turbine and condenser casings and the pipe connections to the latter. It is to be understood that the actual ainount;0f air admitted to the conconnected thereto. I have found, however,- -that-the leakage into the condenser through its joints and adjuncts d- -es not account-for a considerable portion of the air passing into the condenser, but=that a large portionof this air leaks into the system through the supposedly tight joints of the turbine casing at portions 0 the casing where the internal pressure is less than that of the atmosphere.

The joints of the pipeconnections to the condenser proper may readily--be,' and usually are made tight by external bolts. Moreover the parts jointed together to form the condenser casing and, pipe connections tbcreto are not subjected-to severe warping stresses by local and rapidly changingwlift'ercnces in tcn'ipcrature, whereas in the turbinc proper, portions of the casing are' continually changing in temperatureas the load carried by the turbine, and in consequence the steam supplied to the turbine, increases and diminishes. 'My investigations have shown that I-ca'n substantially increase the average efficiency of a turbine plant by effectively preventing leakage of air into the turbine through the joints located'in the low pressure portions of the turbineeasing To accomplish this .result I provide means-tor ing the joints with an air excluding fluid that the leakage into the'turbine easing will be prevented by this air-excluding fluid: 'lheair excluding fluid which l preferto employ is steam ata pressurealuive that of the'\atmosphere. iThis steam may befsupplied directly trom the boiler. or mayvbc drawn throu h suitable conduits from some portion of. the turbine where the'pressure is slightly above .that of theatmosphere;

The various, features of noveltywhieh ichara'cterize inyinvfent-ion are pointed out lea".

with particularity in. the claims annexed hereto and forming a part of this specification.- For. a better understanding of my invent-ion, however, and the advantages possessed by it, reference should. be had to the accompanying drawing'sand descriptive matter in which I have illustrated various forms in which theinvention may be emplrged. f the drawings, Figure 1 is'an elevation.

of a portion of a steam turbine-plant. Fig. 2 is a partial section taken on. the line 22 of'Fig. 1. Fig. 3 is a section taken simi. iarly to Fig. 2 but showing a modified joint.

construction. Fig. 3 is a view similar to Fig. 3 showing a furthermodification. Fig. 1 is a View or a portion of one of the casing parts in 'a construction in which the joint is sealed with steam taken from a high pressure portion of the turbine.

-In the drawings, and referring first to Figs, 1 and 2, Arepresents the turbines, B the condenser connected to the'turbine by the exp'ansible joint'member C, B andB represent the cooli water inlet and outlet connections respectlvelyto. the condenser.

B represents the water of condensation and. B" the air outletconnections, each pipe run-... nmg to a suitable pumpinot shown), for.

withdrawing water or air'from the condensmg chamber: As shown, A represents oints in the turbine casing between adjacent cas-.

ing l parts, the latter being .formed with flanges A 'connecte'd bythebolts A; To

prevent'air from leaking into the interior .of the turbine-- through the joints. A, .or

suchportions of them as are solocated that the steam pressure at their interior edges .is less toanthat of the atmosphere, I secure to the flanges A a sheet metal casing or casings E as by the bolts E. tapped into the flanges A2. N 1th this arrangement a channel or space I? is formed by the casing E and thefianges A. which runs iongitudinally of each joint A and reopen to theouter edge of the joint. Into this channel-or space E" I supply a sealin fiuid, preferably. steam, at a pressure above that of the atmosphere.

. In. consequence any fluid. leaking into-the interior of the-turbine through thejoint A will he steam or other sealing-fluid and not air. As shown, .1 supply esteem tothes ace Ehhythe iping E which may-lead omany suitable source of steam .under pressure exceeding that of-the atmosphere. F represents a pipe connected to a' suitable trap F which may be employed for disposing of water of condensation formed in the space -E*. Itwill lag-obvious however, that the outlet pipe is not essential in all cases as the water of condensation accumulating in the space E forms of itself a sealing fluid effective to revent the leakage of air through the joint when the wateris under a pressure exceeding that of the atmosphere. The

.A" are sealed.

messes water-leaking through the joint will be so small in amount with any ra'ctical'apparatus as not'toappre'ciably' a cot the peraticn of the turbine.

In the modified apparatus shown in Fig.

3 the casing parts AB meeting at the joint A. are. formed with registering grooves A 'in the adjacent faces of the flanges A...

These .unite to form a channel located between theinnei' [and outer edges of .the'jhint I and adapted toreceive the sealing fluid, 'As' shown in Fig. aum bolts A lieon the outer side of the channel for the sealing fluid. An

advantageous modification of this arrangement is shownv in Fig. 3*, in which the abutting flanges of the casing parts AB are formed. with opposed relatively wide and shallow coves A which unite to'form a channel or thesealing fluid through which pass the bolts Asecuringthe flanges together. v In the arrangement shown in Fig. 4 the channelA" formed in the casing part AC opens at AFinto the interior of-the turbine at a point where the steam pressure is above that .of the atmosphere.

It is of course-apparent that the joints of the condenser B an the joints between the expansion jointmem'ber C and theturbine body. roper and the condenser may be 5 sealed y an air excluding fluid in a manner joints'A' and similar to that in which the Whilev in accordance with the provisions of the statutes-I. have illustrated and described the best forms of myinvention now 4 .known to me,';it will be apparent to those skilled in the art that changes may be made in theform of'apparatus disclosed without departing from the spirit of my invention.

Having now described my invention what I claim as -new:anddesire to secure by Letjoint at a portion of the casing at which' the internal pressure is less than that of the atmosphere, of means roviding a channel running along said joint and opening"to said joint at a distance from its inern-l edge, and means for supplying'an air excluding sealing fluid to said channel at'a pressure excee ing that of the atmosphere.

3.-In a turbine casing, the combination with stationary casin parts meeting at a joint at a portion of t "e casing at which'the.

internal pressure is less. than that of the atmosphere and having a channel formed 1,058,986 i a V in the joint forming surfaces extending longitudinally thereof and means for supply.-

ing an air excluding sealing fluid to said channel at a pressure above that of the at mosphere. e

4. In, a turbine casing the combination with stationary casing parts meeting at .a' joint in a portion of the casing at which the '10- sealing the latter with steam at a pressure internal pressure is less than that of the atmosphere, of means local to said joint for above that of the atmosphere.

5. In a turbine casing, the combination with stationary casing parts meeting at a joint at a portion of the casing at which the internal pressure is less than that of the atmosphere,

' of means providinga channel running along .said oint and opening to the latter at a dis-- "tance fromits internal ed e and means for riding a channel running along said joint and opening to the latter at a' distance from the internal edge and communicating with the interior of the turbine casing at a point where the internal pressure is above that of the atmosphere.

- PAUL BANCELQ' Witnesses: v

' Gno. F. FENNO,

EUGENE L, LARKIN.

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