US2537346A - Separation of liquid and vapor in an evaporator or the like - Google Patents

Description

Jan.'9, 1951 R. 0. HENSZEY 2,537,346

SEPARATION OF LIQUID AND VAPOR IN AN EVAPORATOR OR THE LIKE Filed May 20, 1946 Fay 0. Havszsy LM,M+ML&

ATTORNEYS Patented Jan. 9, 1951 UNITED STATES PATENT OFFICE SEPARATIQN or LIQUID AND VAPOR IN AN EVAPORATOR or; 111; LIKE Roy Henszey, 0c0ijon1owoc'; Wis. Application May 20, 194e, Serial sa- 6713147 8 Claims. (01. 1-159+:"j 1*) This invention relates to the separation of liqdid and vapor m n evaporator or the like. The present application is acontinuation in part of my application entitled Evaporator and Separater No. 6Q6 ,097, filed July 20, 1945, and now Patent 2,'512;938; While I may employ two stage separation as suggested in the companion applica'tiori aforesaid, the present case is concerned prii'narily with suel'i separation as is achieved in a single stage, or the first of successive stages, by Ih'e'ah's incorporated in the so-called umbrella bafiles.

It isa primary object of the invention to rejandg-so far as possible, to eliminate entraim merit of liquid the high velocity stream of vapor moving out oi an evaporator. Entrainmeiit'could be reduced by' reducing the vapor velocity so that the force of gravity would allow the part les to fall out-but this would involve the greater expense and space reduired for a lar: er v'a'p'oicha'mber in the evaporator. Accord-, iri' gly, the present ii'ivention seeks to accomplish its objectives first; by segregating peripheral treams 0f li u o h paths o vapor flo'w' secoii dly; by discharging the segregated liquid stram through the peripheral vapor strearhs irito a ump, and third by increasing the veloc-. ity Ofthe peripheral streamer apor; an turning it'int'ga centrifugal force to throw out entrained liquid, all being accomplished" by the umbrella anddorne over the heating element;

Othe ob ects f the inven n will be mad apparent 'by the following disclosure thereof.

in drawi V l ig; l isa iew in'vefrtical axial section through t the upper" portion of an evaporator embodying theinvention,

Fig, 2' is a fragmentary view taken in cross section o'n the iine 2- 2 of Fig. l.

ln general; the'eva'por'ator construction'is conventionalr comprising a tubular jacket I for a heating fluid suchas stea-m, and tubes 2 supplied from sump 3 through pipe lwith liquid which isto beevaporatedi 'Ifhetubes 2 terminate at aheader or tube she'et'i which servesas' a closure fbr thetop of the jacket l.- The sump 3 is at the-hottomofa vap'or'doine 6 fro'm which vapor is discharged through an outlet pipe'i; Ebullition froih'the's'everal-tubes 2 will be quiteviolent wherebyboth'v'apor and liquid willbe discharged from the'tops of the-pipes; In order to preclude the discharge of liquid directly out through the dischargepipel, itis'com'mon to provide a bafiie plate at 8 with margins downwardly curved at 9; such plate-being known to the art as-an umbrella;

he 1min jetted with the vap r from the tit es 2 S ikes th x l 3 91nd w ld t e iii vent'ional apparatixs to be discharged radially etw'army and dovvnwatdly in a thin sheet hem h mar in of t hh' ellh- Th ough this sheet of liquid; all of the vapor formed in the e'vap orator'niust escape to the Qiitletpipe -'I. In pa e ing: through the li thevapor stream,if trays elling at high velocitjcan entrain" a very con der h'l amqun M 1 6 wh a ri d o er with the vapor; thus feasting the effil jiericy' of the evaporatorI A ,Ih m manewi tth itreatm nts,the

m ella af e 8 is'p e fi ha' si ehd s flah s' or sh at fvth' tt tts, d tw rta to at leastth e approximate plane of the tube sheet or header The lower'niar in Hof skirt 1 may bs hea edr tense o e e s i s to be slightly above the level oithe' tubev s eet or considerably therebeneath. The preferred oc ion. i h tt t s hs dei? ut t 411 e en h sl y equ l to lt lth h t e r d a slth ehsek h hrtl the o erlap he grettergthe test s! component 9 s sti the he s the ert .71 ompetent! t e its s ist lhhh s t if s q @s wh he radius Qt th ma gih U u in he grea er hhhct e radi s 9 jack 11- a ver sh d loc i n-is; the marg n I iwe vr o hd. abs ihsh h ist thsthh 0f he J ck t s h1g1 s a nuhr yl hdrit tnes s 45 inche Wide and ne 1 h h ll srh nd t e. t 9 the Jack hile in nt n h e y hth fs shqs heans or break n p n o h i i us stre ths wha wo othe wise he a h e o liqui -i sues ham th I :I oht ihsh sr or resu s thl thgh he s 91 t rbin -bla es i1 1 h ph t e lh i ermlh trtt s r .Ih ss blades mprise l tes 1 t e t p reihsr i w ich re approx ately a r ht ang s to hs sylihtlr tltsk rt l0- ,HQW- evsathe Pla ar .ihsl hed t th v r i a at an e whi h is pre e a l approximatel 455- Wh e th sea e sp in bet een the p a s is ferab y w h si s t so that the ten 3 tends to deflect it upon a hello-ally downward path.

It will be noted that the vapor will also tend to be deflected into a number of helical paths roughly corresponding to the number of helical paths followed by the liquid. The heavier liquid will, however, tend to be on and against the upper sides of the respective plates 15 while the lighter vapor will tend to move in the entire space between the liquid on the top surface of the blades and the surface behind the respective blades along their lower surfaces. Consequently, somt separation between liquid flow and vapor flow i: immediately achieved.

Nearly all of the liquid will move from the tubes into contact with the umbrella. Some small amount of the liquid striking the umbrella will spatter. Thus, some droplets of liquid will be entrained in the outwardly moving vapor without following the path which most of the liquid follows, as above described. In order to catch these droplets, and in order to give tangential and helical velocity to all of the vapor, each of the plates i2 is preferably provided with an inwardly and downwardly disposed flange II which tends to intercept the streams of vapor and such droplets as are moving radially outwardly; The droplets will encounter these flanges obliquely and will tend to flow downwardly along the flanges, whereby the droplets will lose their separate identities and become part of a downwardly moving stream of liquid which will be given an angular motion in the same general direction as the liquid streams flowing from the umbrella into contact with the plate portions l5 of the respective turbine blades. The vapor striking the vanes will be deflected in-a like manner but on leaving the space behind the vanes it will immediately swing upwardly in the form of a vertically rising helix.

j Since the blades are stationary, the liquid delivered from their bottom ends will not be moving either straight downwardly or directly radially. The streams of liquid will move from the blades with components of velocity mainly downwardly, but with components both tangential and radially of the interior of the dome or chamber 6 to strike the liquid in the sump or to strike the inner surface of such dome in a direction quite largely downward and tangential thereto. There the various streams will merge to comprise a sheet of liquid flowing down the dome in a helical direction and there will be but little splattering and most'of the droplets not already merged into a stream will tend to lose their identity upon encountering this fiuid flow, which will return all the liquid to the sump. Droplets which strike the liquid in the sump are below and out of the path of the rapidly moving vapor.

Because the flow of liquid from beneath the umbrella skirt will be concentrated in the streams instead of in a sheet, it will easily be possible for the accumulated vapor to pass between the streams without material entrainment. Nearly all-of the liquid and vapor discharged from the tubes -2 must encounter the turbine blades or vanes [2 before leaving the umbrella and its skirt. The annular space between the skirt H and the jacket I is sufficiently restricted so that the vapor pressures will build up under the urnbrella to accelerate the discharge of vapor and liquid over the turbine blades and thereby to increase the centrifugal effect utilized for separation. The annular space between the margin H of the skirt and the adjacent jacket wall I should desirably be small enough so that the vapor will have a very high velocity. I use ve=- locities approximating as high as 10,000 feet per minute. Theoretically, a velocity of 10,000 feet per minute should yield a tangential component of as high as 7,000 feet per minute, but actually it is much less than this because of friction with the shells and liquid and because of eddy currents and other reasons. However, the starting velocity in a circumferential direction is believed in actual practice to be about half of the theoretical or as high as 3500 feet per minute, thus yielding a centrifugal force, at the start, of 53 G. Even if the average G were one-tenth of this, or only five, it would be a great improvement over more gravity separation.

The velocity given to the liquid tends to throw it quickly out of the vapor. The velocity given to the vapor tends to make it flow rapidly in a path initially downwardly but abruptly turning upward in a rising helix causing any entrained particles to be thrown against the outer shell, from which they flow down to the sump.

Thus, due in part to the centrifugal force developed by the helical direction given to the fluids, and due in part to the segregation of the liquids and vapors into separate paths of flow, and due in part to the arrangement whereby the droplets tend to agglomerate rather than to become atomized by direct impact, a very high degree of separation of liquids from vapor is achieved in the apparatus disclosed.

I claim:

1. In an evaporator comprising a jacket having a tube sheet, tubes extending through th jacket and opening through said tube sheet, and a chamber into which such tubes open providing a sump and a vapor dome and having a vapor outlet, the combination with a centrally open umbrella overlying the tube sheet and of larger area than said tube sheet, of a skirt depending marginally from the umbrella downwardly in surrounding spaced relation at least to a level adjacent the level of said tube sheet, and baffles between the skirt and tube sheet in positions inclined to the vertical and peripherally spaced about the interior wall of the skirt for intercepting and channelling in separate streams the flow of liquid accumulating within the umbrella, whereby to aiford clearance between such streams for the escape of vapor.

2. In an evaporator having a jacket closed by a tube sheet and tubes opening therethrough into a chamber providing a vapor dome and sump, the combination with a, centrally open umbrella having a depending flange extending substantially below the level of the tube sheet in surrounding spaced relation thereto, said umbrella being positioned to intercept liquid ejected from the tubes, of bafiie means comprising plates projecting inwardly from the inner wall of the flange of the umbrella, and respectively inclined to the vertical at spaced points about the periphery of the umbrella flange, said bafile means adapted to inter cept liquid discharged from the umbrella and to direct liquid flow into separate downward streams, whereby to afford passages for vapor to escape between such streams.

3. The combination set forth in claim 1 in which the skirt comprises a substantially continuous wall and the liquid channelling bafiles are mounted on said skirt.

4. The combination set forth in claim 1 in which each blade has a top margin vertically lapping the bottom margin of a consecutive blade.

5. The combination set forth in claim 1 in which said skirt extends below the tube sheet to form an annular passage around the inner shell and in which the bafiies are disposed.

6. The combination set forth in claim 1 in which said skirt extends below the tube sheet to form an annular ring of passage, and the several baiiies are in mutually lapping positions in the passage between the skirt and the jacket.

7. The method of effecting separation of liquid from the liquid and vapor intercepted by an umbrella bafi'le, which method comprises channelling into separate streams the flow of liquid from beneath the baflie, directing said separate streams in one direction axially of the baflie and outwardly therefrom, and withdrawing vapor from the opposite direction axially or" the baflie, whereby to provide spaces between said separate streams of liquid for the escape of vapor.

8. The method of separating liquid and vapor components of fluid ejected from the liquid tube of an evaporator, which method comprises intercepting and tangentially directing such fluid upon a predetermined path having a substantial downward direction and with substantial velocity,

withdrawing vapor in an upward direction and changing the direction of the liquid component of such vapor in the course of its delivery to effect centrifugal separation of such components.

ROY O. HENSZEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 521,946 Cooper June 26, 1894 1,067,010 Dunn July 8, 1913 1,213,596 DeBaufre Jan. 23, 1917 1,298,925 Garriques Apr. 1, 1919 1,562,713 Miles Nov. 24, 1925 1,723,034 I-Iawley Aug. 6, 1929 1,762,493 Wafrous June 10, 1930 1,783,813 Schneible Dec. 2, 1930 2,106,589 Bigger Jan. 25, 1938 2,121,999 Trepaud June 28, 1938 2,172,236 Baumann Sept. 5, 1939 2,399,842 Warner May 7, 1946 FOREIGN PATENTS Number Country Date 457,784 Germany Jan. 30, 1926

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