US1036127A - Method of removing salt from evaporators. - Google Patents

Description

S. M. LILLIE. METHOD OF REMGVING SALT FROM EVAPOR ATORS: 7 APPLICATION IILED DEO.11, 1999."

1,036,127, v PatendA1ig.-20, 1912.

' I sists' of certain. improvements "which' are- SAMUEL MORRIS LILLIE, OF PHILADELPHIA, PENNSYLVANIA.

METHOD OF REMOVING SALT FROM EVAPORATORS.

Specification of Letters Patent.

Patented Aug. 20, 1912.

Applicat'ion filed December 11, 1909. Serial No. 532,696. 7

To all whom t'mayconoem:

7 Be it known that I, SAMUEL Mornns LII in. av continuous manner. orjwithout rupting the flow. of the brine; If.

It has-heretofore been proposed-tocolleet;

LIE, acitizen of the United States, and 'a residentAof'the cityand county of Phila vented an Improvementv in Methods otfRemoving Salt from Evapo-rators,'of which the following is a specification.

\ My invention hasjreference to methods of removing salt from evaporators,andconfully set forth in the following specification and sh n in P i drawings which form a part-.thereoi 'r The object ofmy'invention is to enable the separation and removal. of salt, from evaporators as a continuous process, and also for purifying the separated salt before be- @ingdelivered to the driers or receiving receptacles.

My improved Pihssiiis. viadtinted? 16 be; practised n.;-wah that class ofevaporators in whicht-he salt crystallizedout of the brine-isc0llected in outside pockets and fromwhich'it is preferably removed Pinter};

salt from an evaporatorrby -oirculating the concentrated brine alternately.. through two separate strainer tanks to "strainoutrthe salt,

the strained brine: being returned to the opened and the saltlremoved by hand.

My improved I process consists'. .in drawing 1 evaporator; the strainers being. alternately-i the brine from the evaporator;-. -and. .eausin'gl' it to ;pass to an outsid'place-rwith acurr'entsuspensiom-i then reducing'tthe-"sp'eed .of the current whereby f the salt crystals are --perrnittedftodeposit by gravity,.;andreturning g'the: brine liquor l to the'evaporatohfandz;removingthe de-f;

posited salt continuouslyr without inter-l moval and 1c on veyan'e .Tof the. salt, cleansing Tithe sa'mef'of impurities by washing it by fresh brine'liquor.

My. invention .gw u be' btt mndrabsd by thedescription-hereinafter given in connection withthe 'apparatus illustrated in the drawings, in which: i

Figure "1 is'a sectional elevation of a salt be required. 1 ;.'.Attached test. 7 pocket V is apuinp N, preferably of the p centrifugaltype, saidjpurnpihaving its suctionportopening.intothe'wellfor ocket at its bottom, which connection Inay,i desired, be made in the manner shown inmyU. S. Letters Patent No; 789,159 dated :May 9, 1 @1905. A -discharge' pi'pe n leads from the pump N and be provided with a, controllin ,va-lve f oil-any suitable character. -The "PIPE, aleadsf to a: convenient distance =-;f1-em theievaporatora'nd delivers into a com-" n jo nehofthe side ;'wa1lsw of pyramidally'ijshaped *tank, T, ",which tank serves as the sump for an 'ele-' vatorreferredi'tofihereinafter: This com partrnent-acoverskmeonsiderable ortion of.

partment truncated 'is a plan view of'the fsalt separating and ,cleansing devices. 1 delphia, State of Pennsylvania, have in-'.-

" The evaporator is ingeneral, of the well known'vertical tube construction having a drum D of vertical evaporatinQgt-ubes tfsur rounded with steam, a" dome above the. 7 tubes with a-main outlet 'O for the escape 7 got: .the' vapor produced in the evaporator to the, condenser Sfanda' well or pocket W ,below' the drum. ,Theccnterof thefdrum is provided With? large circulating downtakeflC forming acommunication between jthe dome-R" above the. .tubes ;and. the .well' or pocket. below 'th'e tubesxg Steam'to produce evaporation'maybe introduced inf Lthe drum space'around the tubes througha -C I pipe P, and thewater of condensation-from the drum may pass oflf bya drip pipe df A- pipe m provided with a valve 7* may be employed for charging or feeding the evapj joraton'with brine as -an initial foperati'on, or v *at any othertirne'when additional brine may Y v h -aide wall w =0; the tank T and is 'closed on all sidesexcept the top, at which pIa-ce'the top 'edgeof its inner wall b is paralleltof'th'e top edge of the wall {w of the tankib'uti at aflower level so as to i provide -da m ever ,which the brine is caused to fiOWLf The. space 0' between the walls. o and wis-narrow, but the width of this space 0 increases fromits point of con- 5 nection-"withthe pipe nup-fo its open end,-

at whichlatter place "it isof substantially the fullJwid't-h of the tank, as clearly shown in Fig.'.-2. "In the tank. T opposite to the compartment '0 and its wall'rw is-a transverse partition 7), the upper ed e of which is somewhatjbelow the to' 0 the tank, and the bottom ed' 'e of whic is somewhat above the bottoni o? thetank. The partition 7). divides the tank into two compartments 0' and c and from the compartment 0" a return pipe 11. leads back into the evaporator well at e. This pipe n may have a hand valve f, and also a regulating valve 1; which may be of abalancedvalve type and provided with a float operated lever B which opens and closes the valve accordin to the level of the brine liquor in the tan T. The elevation and location of the float is such, that it will rest on the surface of the brine while the apparatus is in operation and will close the valve 0 before the surface of the brine is lowered below the lower and open end of the return pi e n is reached, and will open the valve wi e before the surface of the brine rises to the top of the tank T. As the brine is forced toward the tank T by the pump N and is drawn from the tank T by the vacuum in the evaporator, it is evident that the circulation of the brine will take place through the pipes 71 and n in a practically continuous manner and maintain the level of the brine in the tank T substantially constant.

E is a bucket elevator of any suitable construction and extends down into the bottom of the tank T through the compartment 0. The bucket elevator may consist of an endless apron or chain I) provided with a series of buckets I) having perforations. The buckets of the elevator travel close to the bottom of the tank T so as to pick up the salt collected therein and elevate it to suitable draining bins or other device for draining the brine from the salt. A pipe 8, Fig. 2, may lead down from the drainage bins or other device for discharging the drainage brine water back again into compartment 0 and by which it may be returned to the evaporator. The elevator moves its buckets in the direction indicated by the arrows and during the earlier iortion of their travel upward, the bucltets move through an alley-way or passage 9 closed on all sides save at the top and bottom, which alley-way extends above the top of the tank T and down as near to the foot of the elevator as practicable and so as to leave just about enough room for the elevator buckets to travel close to the bottom of the tank '1.

A brine feed pipe 2' is arranged to discharge fresh brine liquor to be evaporated into the alley-way 1 near the top of the brine in the same and by which the salt being elevated is washed aiproximately clear of impurities that may 0 associated with it. This washing process is made very ellective by the fact that as the buckets of tho eleva- ,tor rise, after leaving the brine, the fresh brine drains from the salt in the buckets,

escaping through the perforations therein. The supply of this fresh brine liquor may .be controlled by a hand valve it.

My improved process will now be understood, and may be described as follows: The evaporator is charged with brine through pipe m to a level above the upper ends of the tubes t and approximately to the level indicated by the dotted lines. All the valves in the other pipes connect-ing the evaporator are closed during this operation. The tank T is also filled with brine through the ipe '11 until it reaches the level indicated by tiie horizontal dotted line. Steam is then turned into the drum D to heat. the tubes 1. for evaporating the brine, the circulation of the brine taking place upward through the tubes t and downward through the large centraldown-take Qasindicated by the arrows. In the evaporation which thus takes place, the brine will be concentrated in the upper part of the evaporator, the circulation therein bringing new portions of the brine into contact with the evaporating pipes, and the salt crystals which are. suspended in the circulatim brine together with the brine in which they are suspended, are led or caused to ass, in the course of the circulation, through the body of brine at the lower part or well of the evaporator in which there is a sulliciently quiescent brine to insure the depositing of the salt therein by gravity. The centrifugal pump N is then started, and the hand valves f and f are opened so that the well \V of the evaporator is in couununication with the tank T by the pipes 71. and n. The valve is adjusted to the extent needed to give t ie desired volume of movement of the brine from the evaporator to the tank T and back through the pipe 12. into the evaporator to insure the proper working of the process. in this manner, the salt deposited in the evaporator is transferred in a current of brine from the body of quiescent brine in the ewiporator and doposited in a second body of suflicicutly quiescent brine separate from the evaporator and its circulating brine to insure the depositing of the salt entirely outside of the evaporator. It is to be assumed that the conditions are such, due to the vacuum in the evapm'ator, that the brine will flow back into the evaporator from the tank '1 through the return pipes 11 when the valve f therein is opened. It is also evident that if the tank '1 is elevated at the proper level, the flow of the brine back into the evaporator would take place by gravity, with or without the assistance of the partial vacuum. it is immaterial whether the brine returns by gravity, or by the partial vacuum, or bv both. The vapors from the. brine are drawu oil from the evaporator through the outlet '0 into the condensers S, and after the ration, salt crystals which are hereinafter termed, salt commence and continue to separate fromthe brine as longhas the evaporation from it continues. is salt moving with the circulating brine, being heavier than thebrine, will, on leaving the bottom of the down-take C, settle through the brine to the bottom of the well W, from which it passes with the brine which, by the centrifugal pump N, is forced through the pipe n into the compartment 0 on the tank T, the said travel of the brine and salt through the pipe n having a speed which is regulated by the hand valve f, the said speed being suflicient to keep the salt in circulation with the brine. This brine, moving with the regulated speed suificient to carry with it the salt, enters. the compartment 0, rises through the same, and overflows at the top into the compartment 0 of the tank T, and flows across the surface of the body of the brine in the tank T until it reaches the other side of the partition 7), and enters the compartment 0', and thence through the return pipe n back into the evaporator, at e; As the moving brine, after leaving the pipe n, gradually reduces its speed of flow and travels across the compartment c at a comparatively slow speed, the salt which it bears, or the bulk of it, falls-by gravity and settles through the comparatively stagnant or quiescent brine between the partitions 0 and p, which prevent horizontal motion in the compartment 0 to the bottom or pocket of the tank, indicated at 'w', whence it is removed by the buckets of the-elevator E. It is subsequently delivered into the draining bin or draining device reviously referred to (but not shown), and

- elevator with the salt drains more or less perfectly from the salt and passes back into i the tank T by the pipe 8.

Aside from the above described process for separating and removing the salt, the process of cleansing it during its removal is accomplished by feeding the fresh brine for use in the system through the pipe 2 into the alley-way g, and which in descending,

V bottom of the tank rises slowly through the same against the settling salt andjoins the current of the impure evaporator brine moving across the surface of the liquid contents this level can be constantly changed by which devices are' well known. The brine which goes up the upon the extent of of the tank. Both the alley-way g and the lower portion of the tank T are thus kept filled with the fresh brine, and the salt which settles from the upper current of the brine, is washed by the incoming fresh brine first in the tank T and then in the alley-way g, and in its course meets with brine of increasing conditions ofpurity.

During the operation of the apparatus,

the float B operates the balanced valve 4) in such a manner as to maintain a substantially constant level of brine in the tank T, but as the addition of fresh brine through the pipe 2', it is evident that the level of the brine in the evaporator may be controlled bythe hand valve 72. in the brine pipe 0'. As contrasted with feeding the fresh brine into the body of the eve orator (as by means of the pipe m and va ve 1') the feeding of the fresh brine into the passage for the outgoing salt ,and operating 1n such manner that the salt as it leaves the system is caused to pass through and washed by the incoming fresh brine, possesses the advantage of yie ing a somewhat purer salt, for the reason that salt as it leaves the evaporator is mixed with.

and is wetted by brine in which impurities,

matters other than salt, have been more or less concentrated by evaporation from the brine, and which, were it not for the washing by the incoming fresh brine, woulderemain with the salt being elevated and would pass into the bins. This'salt moistened with impure brine and then dried would be contaminated. When, however, it is washed by the incoming fresh brine in which the impurities have not been concentrated by evaporation, the salt oes into the bins moistened by this purer rine and consequently it is, to that extent, a purer salt. proved method of'feeding fresh brine to the system also results in an economy of'heat, if the fresh brine be of atemperature lower than that of the brine in the pan, or evaporator, because the salt goes away at the temperature of the former instead of at the temperature of the latter. Brine often goes to evaporators at about 60 degrees Fh.,while the temperatures in the evaporators vary from, say to 190 degrees Fh., depending vacuum carried in the evaporators. v I

From the foregoing it is assumed that the relative pressures in the evaporator and in the tank T are such that the brine will, un-

assisted, flow back through the pipe a into the evaporator and that assistance such as the pump N is required only to deliver the brine into the tank T. Should the relative conditio ns be such, however, that the brine wouldnot thus flow back unassisted through the pipe 42, then any suitable means, such as the pump, may be employed to assist the return flow to the evaporator.

. 25.1 parate application.

The tank T and its adjuncts serve'as a means for separating the salt from the brine circulating from the evaporator back into itself, and while I have shown means which are excellently adapted for the purpose, any other suitable means forv securing the same results may be employed in lieu thereof without departing from the spirit of the invention. It is also a parent that the salt vseparating device, of w nch the tank Tend,

elevator E are parts may be located at any distance from the evaporator or in any suitable position as to elevation, so long as there is sufficient motive power provided to deliver the brine through the tank of the separator "device, and to lnsure the return of, the

brine from the se arating ;device' to the evaporator. It is a sozto be understood that the'particular form of the evaporator which 1 have shown, by way of explanation of my improved process, may be substituted by any other well known form of evaporator.

In this application I do not claim the apparatus shown, as the, same is reserved for a Having now descrlbed my invention what '1, claim as new and desire to secure by'Letters Patent, is: I l 1. The herein described process ofvmanufacturing salt from brine which consists in concentrating'in an evaporator a brine circulating in the same-and thereby forming 5 ing the deposited saltfrom the latter con tinuously as it is deposited.

2. The herein described process of manufacturing salt from brine which consists in concentratingin an evaporator a brine cirpopulating in thesame and thereby forming salt crystals suspended in the circulating brine and leading the brine in thecourse of its circulation through a body of sufiiciently quiescent brine to insure depositing the salt 55. therein by gravity, then in transferring this deposited salt in a current of brine from the body of quiescent brine in the evaporator to and depositing it in a second body of sufli-' ciently quiescent brine separate from the evaporator and its circulating brine, in returning brine to theevaporator from the second body of quiescent brine, in removing the deposited salt from the latter, and in passing fresh brine into the brine being re turned to the evaporator and at the same automaticallyregulating the discharge 0 time washing't-he salt during its removal by causing'it .to pass through the said fres brine on its way to the evaporator.

3. The herein described process of manufacturing salt from brine which consists in concentrating in an evaporator a brine circulating in the. same and thereby forming salt crystals-"suspended in the circulating brine and leading the brine in the course of its circulation through abody of sufficiently qliliiescent brine to insure depositing the salt t erein by gravity, thenin transferring this deposited salt ina current of brine from thebody-of, quiescent brine in the evaporator to and depositing it in a second body of sufii- 30 ciently quiescentbrine separate from the evaporator and its circulating brine, in re- ;turning'brine to the evaporator from the second body of uiescent brine, in removing thedeposited sa t fromthe latter, washing 5 the salt durin its removal by causing it to I pass directly t'irough a body offresh brine,

and in causing said fresh brine to be subsequently delivered into the evaporator after it has been utilized to wash the salt. a go 4. The herein. described process for the manufacture of salt which consists in concentrating a brine solution in an evaporator, transferring the concentrated brine solution with its suspended salt under a rapid flow into a'vessel outside of the evaporator in which a large body of brine is provided and maintained through which the salt is deposited and introducing the concentrated brine .into the upper portion of the body of the brine in such' manner that the speed of flow of the incoming brine is reduced relatively to its speed of flow in the vessel, returning the brine solution to the evaporator? the brine from the vessel in which the salt is deposited to the evaporator under control of the level of the brlne in the vessel, and

removing the deposited salt from the brine liquor in the vessel at theplace of deposit. no

5. The herein described process of manufacturing salt from brine which consists in concentrating in an evaporator a brine circulating in the same and thereby forming salt crystals suspended in the circulating'llo brine and leadingthe brine in the course of its circulation through a body of sufficiently quiescent brine to insure depositing the salt therein by gravity, then in transferring this deposited salt in a current of brine from the body of quiescent brine in the evaporator to and depositing it in a second body of sufiiciently quiescent brine separate from the evaporator and its-circulatln brine, and in removing the deposited salt tom the latter continuously as it is deposited.

6. The herein described process forqthe manufacture of salt which consists in cansing the salt from a concentrated brine solution to settle in an evaporator itself, removing brine to be concentrated and the salt' the salt from the evaporator, passing the sa t thus removed from the evaporator through fresh brine to wash it of precipitated impurities, and subsequently delivering the fresh brine so employed to the brine circulating in the evaporator.

7. The herein described process for the manufacture of salt which consists in causcrystallized therein to settle in the lower part of the evaporator-itself, positively removing the salt associated with concentrated brine from the evaporator m a continuous manner and transferring it to a place entirely outside of the evaporator and there causing a second settling'of the salt from the concentrated brine, removing the deposited salt from the brine at the place outside of the evaporator and washing the said separated salt with fresh brine solution, and 'subsequently'conveying said washing brine solu-. tion into the eva orator. a 8L Theherein escribed process of manufacturing salt from brine which consists in concentrating in an evaporator at a pressure below atmospheric pressure a brine circulat-' ing in the same-and thereby forming salt crystals suspended in the circulating brine and leading the brine in the course of its circulation through a body of sufiicientl 'quie'scenfi brine to insure depositin the salt therein y posite salt in a current of brine from the body of quiescent brine in the evaporator to and depositing it in a second body of sufli-- ciently quiescent brineand existing under atmospheric pressure and separate from the evaporator and its'circulatin brine, and in removing the deposited salt rom the latter.

9. The herein described method of manufacturing salt, which consists in concentrating in an evaporator a brine'circulating in the same and thereby forming salt crystals suspended in the circulating brine and leading the brine in the course of'its circulation 'rator an avity, thenin trans erring this de-' through a body of sufliciently quiescent brine to insure depositing the salttherein by gravity, then transferringrthis deposited salt m a current of brine brine of the evaporator to a place wholly outside of the evaporator and the zoneof cm the quiescentevaporation and into a second body of'sufii' ciently quiescent brine. separate from the evaforator and its circulat-mg brine and at San second bod of quiescent brine causin quiescent brine continuously a hot brine solution in an evapolower part, positively transferring the concentrated brine solution with its suspended saltto a cooler lace wholly outside of the evaporator and t ereby causing the suspend -v ed salt to be deposited by gravity througha quiescent body of brine, returning the. brine solution separated from the deposited salt again to t e evaporator, mechanicall removing the deposited salt from the rine liquor at the place of deposit outside of the evaporator during the circulation of said brine liquor, and'supplying additional fresh brine to the circulatlng brine through the salt being deposited to compensate for that which is eliminated by the evaporation of the water and crystallization of the salt and for washing the salt before its removal. In ,testimony of which'invention, I hereunto set my hand. 1

Witnessesz-v R. M. HUNTER, x R.'M.KELLY.

s. MORRIS LILLIE. ,I j a 55 the circulation t erethrough of the suspen

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