US1215321A - Ejector. - Google Patents

Description

M. ,LEBLANC.

, EJECTOR, APPLICATIDN FILED JUNE 22.19l5

1,215,321." U Patented Feb.6,1917.

' ZSHEETS-SHEE'T l- INVENTCW HIS A'I'TOFPIJIEY IN FAG?" efficiently in withdrawing air or non-condensable vapors from a condenser or slmllar' UNITED STATES PATENT UhblUE.

MAURICE LELBLANC, or vAL-sUn-sEmE,

CROISSY, FRANCE, ASSIGNOR "J10 SOGIETE ANONYME POUR LEXPLOITATION DES PBOCEDES WESTINGHOUSE-LEBLANC, O1"

PARIS, FRANCE.

Specificaticn of Letters ifatentr Application filed June 22,1915. Serial No. 35,647.

To all whom it may concern.

Be it known that I, MAURICE LEBLANC, a citizen of the Republic of France, residing at Val sur Seine, Croissy, Seine et Gise, France, have made a new and useful Improvenient in Ejectors, of which the following is a Specification.

This invention relates to ejectors and has for an object to produce an'eiiicientejecting' apparatus having a high ratio of compres sion. v

A further object is to provide. a multistage ejector, which is capable of operating apparatus and is capable ofumaintaining a relatively-high vacuum in the condenser or the apparatus from which the non condensable vaporsor fluids are withdrawn.

A {furtherobject is to produce an ejecting apparatus which is simple in construction ,and is capable of operating effectively with a minimum amount ofmotive or inipelling fluid, for convenience of description herein after termed steam, in compressing an-elastic fluid, such as air, from a relatively low to a relatively high pressure.

These and other objects, which will be made apparent throughout the further de scription of the invention, are attained by, I means of apps.

ratus embodying the featuresherein descri ed and illustrated in the drawings accompanying and forming a part hereof. j J

In the drawings; Figure ;1 is a'more or less diagrammatic sectional view illustrating an ejecting apparatus embodying my invention.

Fig. 2 is a view. corresporiding to Fig. 1

showing the, ejecting apparatus operativelyconnected to a surface condenser.

Fig. 3 is a curve showing different quantities of steam necessary for operating the ejecting apparatus having different ratios of compression in the different stages.

Ithas been proposed to employ eject'ors as vacuum pumps or for withdrawing non-con densahle gases from condensers. The advantages of such an arrangement of a .pa-

ratus are apparent and result primarily rom the fact that there are no moving parts employed in an ejector and consequently it does not need special and constant care. An ejector operating as a. vacuum pump tnustcompress air or the non-condensablo vapors withdrawn from the condenser from an absolute pressure corresponding to 30 Patented Feb. 6, 1917,,

of mercury or approximately of a pound absolute to atmospheric pressure, or to approximately 141} pounds absolute, or 760 M.

Mfsof mercury. In other words, the ratio of compression of such an apparatus openatin under such conditions is approximate y the same as would be encounteredin compressing air from atmospheric pressure to approximately 435 pounds above atmosphere. So far as I know, no simple and commercial ejecting apparatus has beenproduced up to the tune of my present invention for handling such high ratios of. compression as those described.

Various ejecting apparatus have been pro-- of compression and the result is that the.

second and subsequent ejectors of the series have to employ large quantities of the steam for the purpose of compressing and removing not only fluid ejected by the preceding ejector but also the steam or ejecting fluidv employed intthe preceding ejectors. As a result,'the -eflicieney of such apparatus isso low as to be prohibitive.

In order to reduce the amount of steam necessary for operating the second and sub; sequent 'ejectors ofvthe series, it has been I proposed to employ a separate condenser between each ejector of the series for the purpose of condensing the steam. employed as motive fluid in each ejector of the series and of thereby relievingthe second and subsequent ejectors of the burden of removing the steam as well as the fluid to be ejected, which is discharged from the next preceding ejector. Suchapparatus fulfils its urpose" vbut it is complicated, expensive to manufacture and to maintain, and introduces new difficp1t1es not encountered 1n s1mp1e' eject- My invention, therefore, is to produce a] c simple and effective ejecting apparatus,

which is dapted to operate effectively-and; i

to accomplish, with a minimum amount-(i119 steam, the desired compression of the fluid to be ejected: The apparatus illustrated as an embodiment of the invention comprises a multi-stage ejector in which the separate ejectors operate in series and are so proportioned and arranged that the ratio of compression of the first, ejector is small in comparison with that of the second or subsequent ejector.

lhe ejecting apparatus shown in .the drawings includes two ejectors, the first of which receives the air or noncondcnsahle fluid from a condenser or vessel to he evacuated and the second receives the mixture of the fluid ejected and motive fluid discharged from the first. For convenience otdescription, the second ejector may he termed the principal ejector, while the first may be termed the augmenting ejector. If the ratio of compression of the first or augment high efficiency and the quantity ofsteam employed in proportion to the quantity of air removed from the condenser or vessel to he cvacuatial will he small; consequently the total quantity oi" fluid discharged by it to the second or principal ejector will not be, large in proportion to the amount of air or non-comlensahle fluid'ejected.

For example, to remove 10 kilos (approximately 22 pounds) of air per hour from a condenser or vessel having an internal pressure corresponding to 30 M. M.s of mercury (approximately .6 of a pound absolute) and to compress this air to a pressure cor responding to 100 M; M.s ofmercury (approximately 2 pounds absolute) the first ejector will employ about 20 kilos of live steam. Ihe tot'al quantity of fluid discharged from this first ejector will therefore he 30 kilos and it will be necessary to cmnpmss this quantity ol fluid. to atmospheric pressure in the principal ejector of the series. The quantity of fluid delivered to the principal ejector is therefore greatly diminished below what it would be if the two cjcctors of the series were operating under the same. compression ratio, and the second ejector is capable of compressing and removing, with comparatively high efficiency, the relalivelysmall quantity of fluid delivered to it.

Theory and experience demonstrate that increasing the compression ratio of the first or augmenting ejector necessitates an increase in the amount of fluid discharged by the organized apparatus, and even it the compression ratio of the second ejector reduce-cl a im-rrcsponding amount-Irv increasing liu': corupl ssion ratiool' lhv lirst ej tor. the llYU Fienm necessary in. the second ejector, .l'or a complishing the compression the first ej tor, increases rapidly with an increase an the rattopl l'OlllIJBSHlUIl ol' the mg ejector is small, it will operate withfirst ejector of the series, and as a result the cllicicncy ot' the organized ejecting apparatus is materially reduced.

The 'curve in' Fig. 3 graphically illustratcs this. It shows the different amounts of steam necessary, in apparatus such as illustrated in Fig. 1, for ejecting or withdrawing a given quantitys of elastic iluid from av region of lowpressure,-.6 of a pound ahsoluteaml discharging it at atmos mcric pressure when ditl'ercnt ratios of compression are-employed in the augmenting or first ejector with relation to the ratio of compression employed in ,lhe principal ejector. In this figure the ordinates indicate steam or motive fluid in kilos and the abscissa the quotients resulting by dividing the ratio of compression of the augmenting or first ejector by the ratio of compression of the principal or second ejector.

Reference to the curve will show that it theratio of compression of the augmenting ejector is l/rz ot' the ratio of compression of the principal ejector, approximately 800 kilos of steam will be necessary for accomplishing the compression of elastic fluid; whereas, if the ratio of compression of the cementing ejector is increased to 1/11 of that of the principal ejector, the quantity of steam necessary for accomplishing the same compression will be approximately 1,200 kilos.' From this it will be seen that.

the quantity of steam increases rapidly as of compressioh of the principal ejector is relatively lar ge as compared with the ratio of compression of the augmenting ejector. inference to thecurve shows that there is a minimum ratio of compression which. can he employed in the. first ejector and that after that minimum is reached a further decrease in the ratio of compression of the first ejector occasions a falling off in the elliciency of the apparatus. It may be well to state that high compressions absolutely cannot he obtained with a single ejector and that while the curve is approximately correct in showing the rise. in the amount o'l' steam employed as the size of the first ejector is reduced below the determined sage, which as illustrated, consists of a convergent divergent tube serving as a combined combining tube and diffuser; The receiving chamber 8 is provided with a port 10, which is adapted to communicate with the condenser or-vessel to be evacuated.

The discharge end of the augmenwz'ng ejector 4 or the divergent end of the tu' 9 communicates with and delivers the Il-uid. traversing it to the inlet end of the combinconverging streams into the combining t 'fbe' '11.

The discharge end of the combining tube communicates with a convergent diverging tube or diffuser 14, which is axigly alined with and forms a part of the c n vergent divergent working passage of the ejector 4 and communicates with the atmosphere or with the region-into which the ejector discharges A plurality of orts'or nozzles 15 are I shown around the ischarge end of the tube 11 and located between it and the adjacent Wall of the tube 14 and in the vicinity of the throat of the tube 14. These ports or nozzles 15 communicate at their outer ends with the atmosphere or with the region into which the ejecting apparatus discharges and are. .adaptedto admit a sheath of fiuidor air to the interior passage of the ejecting apparatus for the purpose of varying the efiective throat of the ejector 5 to meet the varying conditions encountered during the operation of the ejecting apparatus.

In ejectors operating under-high degrees of compression it is essential to accurately design the fluid passages for the amounts of fluid traversing them and consequently war ati'on's' in the pressure ofthe fluid at the inlet end of the ejector orvariations in the amount of fluid. traversing the ejector will either cause the apparatus to operate unsatisfied torily or render i-t inefiective'. If it is con sidered that the pressure p is to be maintained in the chamber 8 and that the pressure P is the pressure existing at'the discharge end of the ejectingapparatus, it wi 1 be ap arent that the dimensions ofithe dif- 'sion in ordinary serviced fe'ren parts of the ejector will be a function a of the ratio g. n will therefore bellm stood that it an ejeetonsuch as illustrated, "isdesigned to obtain a high degree of compresdimensions will not be suitable for chamber S'into a conver ent divergent pas be made, elastic is incl or'for operation .when'the'pre'ssm'e p isvanedi At the moment of starting the ejector the pressure in the chamber 8 is equal to the pressure P and consequently the steam issuing from the nozzles 6 is over expanded, for the pressure eaistingin the chamber 8 and the noazlesdoes not operate efliciently' On the other hand, the density of the. fluid entrained in the chamber 8 is much greater than under normal operatin conditions and hence a larger quantity of luid is delivered to the ejector 5 than is the case under normal operating conditions. if the throat of the combined tubes 11 and :14: has been designed for normal operating conditions, it will be toosmall for starting and the ejector i willeither be started with di flic'ulty or will not start at all, due to the choking atthe throat. If, on the contrary the throat of the combined tubes 11 and 14 redesigned toacconimodate the flow of fluid encountered during the-starting operation it will be too large to operate e ectively during the normal operating conditions and as "a result breaking down will occur, by whichis meant that momentary equalization will take place 3 between the pressure at the outlet of the tube -14 and the Inlet of the tube 11, which will render the apparatus .inefi'ective.. I If the,

throat of'the combined tube is not o f'suificient area to'passthe fluid encountered during the starting operation-buteven. so is too large for the amount of fluid delivered .to it during normal operation, the fluid will not fill the tube and as'sbon as this condition ex ist's eddies will be formed within the stream of fluid which interfere with the p -h tion ofthe apparatus and will ordinarily res. in These difliculties sult in brea down.

could be avoid'e if the walls of the diffuser 14 or of the combined tubes and l l oould able them in j the fluid 0 lumn treversin them. This resalt, however, is obtained y nozzles 15 .inlthe combined to rovid' the 1 1 511 14.

and locating themflat the place where the. a

fluid column traversing the tubes tends to detach itself from the walls when insuliproportion the enact the throat iniao'co ance with the amount of 'fluidfltraver'ainf the;

tabs 11. This sheath iwillact an stic wall and will revent the, column oi fluid issui -from t 0 tube 11 from expanding and t as givin 'rise-totddies orQcreetiuE the tendency or the apparatiis tdbrea down. nozzles not only" deliver the filling sheath of fluid t'o. thefconden ser bnt during the o emtion of starting excess fluid is discha j v efiective am of the throat ofthe combined from-them and as a rosultthe tubes 11 and item be automatically use ,1

. c 10.5.. such a manner as to en'- Y themselves at all times to to suit all existing conditions of fluid flow, and the apparatus will not only be selfstarting, but will operate efliciently under normal operating conditions. The nozzles 15 may be replaced by a single annular nozzle if desired. The nozzles 12 may also be replaced by a single a1n1l1lai"nozzle, if desired.

In-Fig. 2 I have'illustrated the ejecting apparatus as applied to a surface condenser 2.0. In such an installation the chamber 8 is placed in communication with the air or non-condensable fluid ofi take of the condenser. It will however be apparent that ejecting. apparatus embodying my invention maybe employed in connection with any ty e of condenser.

In the drawings I have shown a. pipe 21 for delivering live steam or motive fluid to the chamber 13, of the principal ejector 5, and a valved pipe 22 between'the chamber 13 and the chamber 7 of the augmenting ejector. It will, however, be understood that the main steam supply may be delivered directly to the chamber 7 and that the convergent divergent tube 9 may be made in two parts, one converging and one diverging, that the tubs 11 and 14 may be replaced by a single tube vand that various changes, modifications, substitutions, additions and omissions may be made in the apparatus without departing from the spirit and scope of the in- -vention as set forth in theappended claims.

lVhat I claim is:

1. In combination. in an ejecting apparatus, a principal ejector comprising a combined combining and difl'user tube having an inlet to which fluid to be ejected is delivered,

' and at least one expansion nozzle for delivering fluid to said tube, and an augmenting ejector having a relatively expansive small ratio, of compression compared to the ratio of compression of the principal ejector arranged to communicate with the source of fluid to be ejected and to discharge'both the fluid ejected and the motivefluid delivered to it to the inlet of the principal ejector.

2. In an ejecting apparatus, a plurality of steam actuated ejectors arranged to operate in series on the fluid to be ejected, the first ejector of the series communicating with the' 'source of fluid to be e ected, and having a relatively low ratio of compression as compared to the ratio of compression of the second e ector of the series.

3. An ejecting ap mratus including any ejector cmnprisin'g a convergent divergent tube communlcatnig at its inlet with a source of fluid to be ejected, an expansion nozzle fordclivcring expansion motiic fluid to said tube and asou rce ol' motive fluid supply communicating with said nozzle, and a secondlexpansh'e 'fluid actuatml ejector communicating with the outlet of the tube of the first ejector aml'having a relatively large ratio of compression as compared to the ratio of compression of the first ejector.

4-. An ejecting apparatus including athe series receiving all of'the fluid traversing ratio of compression, the second ejector of I the'tirst ejector and comprising a convergent divergent passage to which the fluid discharged from the first ejector is delivered, and an expansion nozzle for delivering expansive motive fluid to the passage, said second ejector having a relatively high ratio of compression.

6. In combination with a condenser, a, vacuum pump comprising two ejectors opcrating in series, the first of said e ectors including a convergent divergent passage, a mixing chamber. communicating with the inlet end of said passage and withthe condenser, and a plurality of motj ve fluid supply nozzles rejecting into 'said. mixing chamber for elive'ring motive fluid to said passage, the second ejector of the series comprising a convergent divergent passage communicating at its inlet end with the discharge end of the first mentioned passage and having at a point intermediate its ends openings communicating with the discharge end thereof, and a series of expansion nozzles surrounding the discharge end of the first mentioned passagefor delivering motive fluid'to the second mentioned passage, the ratio of compression of the first ejector being small with relation to the ratio of compression ofthe second ejector.

7 In combination with a condenser, a vacuum pump comprising two ejectors Xially alined and arran ed to operate in series, the first consisting o a convergent combining tube having an inlet for fluid-to be ejected, a divergent diffuser and at least one divergcn't'nozzle for discl1arging 'motive fluid through said convergent divergentmember,-

tube of the second ejector, the ratio ofcom ression of the first ejector being materially ess than the ratio of compression of the second ejector of the series.

8. An air pump comprising a. number of divergent nozzles cooperating with a single .combining tube and a diffuser for initially compressing air to be compressed, a second set of divergent nozzles eotiperating with a second combining tube, and a second difi'user both axially alined with the first combining tube and difluser and communicating therewith, and means for delivering steam to both sets of nozzles, said second set of nozzles andcoiiperating combining and diffuser tubes having amaterially greater compression ratio than that of the first set of nozzles and cotiperating and combining and 9. In combination with a condenser, a vacuum pump comprising an e ector having a relatively low ratio of'compression com-- lnunicating with the air ofitake of the condenser and having a convergent divergent working passage, and an expansion nozzle for delivering motive fluid to said passage,

a secondejector having a relatively high a ratio of compression and provided with a I nozzles.

convergent divergent working passage com municatingwith the outlet of the first mentioned working passage and provided with means for varying the effective throat'there of in response to variations in the amount of fluid delivered thereto, an expansion nozzle for delivering motive fluid tothe workingpassage' of the second ejector, and means for delivering motive fluid to both of said 10. In combination in an ejectingappm ratus, two ejectorsoperating in series,'-the,

first ejector of the series conununic'ating with the source'of fluid to be ejected having a relatively low ratio of compression,;the second ejector of the series receiving all the fluid discharged from the first ejector, and

having a convergent divergent working pas sage provided with means for varying the effective throat thereof in accordance with variations in the amount of fluid passing therethrough, a series of expansion nozzles for delivering motlve fluid to sa1d passage and means for delivering motive fluid to said nozzles, said second e ector having a relatively high ratio of compression.

11. In combination with a condenser, an

expansive-fluid actuated ejector comprising an inlet passage communicating with the air ofitake port of said condenser, a divergent nozzle for expanding and delivering motive fluid, a combining and diffusion tube communicating with said inlet'passage" and receiving the expanded motive fluid delivered by said nozzle, a second expansive-fluid actuated ejector having a ratio of compression materially greater than that of the first ejector and comprising a difiuser communidivergent nozzle for expanding and delivering motive fluid into and through the diffuser, 'and means for delivering expansive motive fluid'to the nozzles of both ejectors.

12. In combination with a condenser, an ejecting apparatus for withdrawing air and non-condensable vapors from the condenser, comprising two expansive motive fluid actuated ejectors operating in series, the first ejector of the series comprising a combining and diffusion tube and at least one expansion nozzle of gradually increasing area from the" throat to the outlet thereof, for expanding motive fluid to sulistantially the pressure at the inlet of the combining and diffusion tube and for disclmrging the expanded fluid into the combining and diffusion tube, the second ejector comprising a combining and difi'usion tube, and at least one expansion nozzle gradually increasing in area from the throat to the outlet thereof, for expanding motive fluid to substantially the pressure at the inlet of said last mentioned combining and diffusion tube, and means for delivering expansive motive fluid to the nozzles of both ejectors, the second ejector of the series having a materially greater ratio of compression than that of the first ejector of the series.

I 13. In combination in an ejecting apparatus, an ejector including a combining and diffusion tube, communicating at its inlet end with the source of fluid to be ejected, and at least one nozzle having gradually increasing areas from the throat to the outlet thereof for expanding motive fluid to substantially the pressure of the fluid at the'inlet of the combining and difi'usion tube and for discharging the fluid so expanded into and through said tube, a second ejector of a materially greater ratio of compression than the first ejector, operating in series with the first ejector and including a combining passage communicating with the outlet of the first ejector, and at least one nozzle gradually increasing in area from the throat to the outlet thereof for expanding motive fluid to substantially the pressure at'the inlet ofthe combining passage, and for discharging the fluid soexpanded into and through said passage and means for delivering expansive motive fluid to the expansion noziflesgoj both ejectors.

1+. In combination in an ejecting appara tus, an ejector including a combining and diffusion tube communicating at its inlet end with a source of fluid to beejected, and at least one nozzle gradually increasing in area from the throat to the outlet'tliereof for expanding motive fluid and for discharging pression than the first ejectoroperatin in series therewith and comprising a co in;

ing passage communicating with the outlet of the first ejector, at least one nozzle gradually increasing in area from the throat to the outlet thereof for expanding motive fluid and for dischargiire the expanded motive fluid into and through the combining passage, and means receiving combined fluid media. from the combining passage for reducing the velocity of the combined media passing therethrough and thereby increasing its pressure.

" '15. In combination in an ejecting apparatus, an ejector including an inlet passage, a nozzle gradually increasing in area from the throat to the outlet thereof for expanding motive fluid to substantially the pressure existing in said passage, a combining and diffusion tube communicating with said passage and receiving the motive fluid discharged troin said nozzle and the entrained fluid medium train said passage, :1 secondejecting device at materially greater compression ratio than said ejector, and includmg a combining passage communicating with the outlet of said ejector, a nozzle of gradually increasing area from the throat to the. outlet thereof for expanding motive fluid, to substanlially the pressure normally existing at the inlet of said combining passage, means receiving the expanded fluid issuing from said last mentioned nozzle and the medium entrained thereby and for effecting a conversion of the kinetic energy of the fluid media passing therethrough into potential energy as represented by an increase in pressure, and means for delivering eX- pansive motive fluid to the nozzles of said ejector and ejecting device.

16. In ci'nnbination in an ejecting apparatus. an ejector comprising an inlet communicating with a source of fluid medium to be exhausted, a nozzle of gradually increasing area from the throat to the outlet thereof for' expanding motive fluid to substantially the pressure normally existing in said inlet passage, a combining and diffusion tube communicating with said passage and receiving the motive fluid discharged from said nozzle and entrained fluid medium from said passage, a second ejecting device haying a ratio of compression materially greater than that of said ejector. and including a combining passage communicating with the outlet of the ejector, a nozzle" of gradually increasing area from the throat to the outlet thereof for expanding 'motive fluid to substantially the pressure existing at the inlet of the combining passage, and means communicating with said passage, and receiving the expanded motive fluid issuing from said nozzle and the entrained fluid medium from said passage for effecting a conversion of kinetic energy of the fluid media passing therethrough into potential energy as represented by an increase in pressure, and means for delivering expansive motive fluid to the nozzles of said ejector and ejecting devic In testimony whereof I'have hereunto subscribed my name this 28th day of May, 1915.

MAURTCE LEBLANO.

It is hereby curtifiod that in Letters Patent No. 1,216,321, granted F.-.brunry 0',

1917, upon the application of Maurice lieblunv, of YnLsur-Soine, Crnissy, Franco,

for an improvenmnt. in Ejectors, 0mm; appear in t-hu printed specification requiringcorrection as follows: Page 4,1il1e 40,-Inim Lhvfun-1hewordfluid"insen the word ezyxmsive: snmn pagfl and claim, line 41,5Lriku out Huwnrrl "cxpansive same page, line 50. claim .2, hrfore the word fl-uid" cumvl L110 article the same page, line 60, luim 3,1'nr Um word "0x puusiun rluui erpwn in: Mld that the said Letters Patent slmulfl be mad with Liman uni-reunions Lherein that. the sumo may conform [-0 the record 0! the case in the Pamm ()Tfilm Signed and scaled this 20th day of March, A. D., 1917.

[BEALJ F. W. H. CLAY,

Cl. 230-43. Acting Cmnrm'uior er ofPatenta.

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