US1617081A - Evaporator - Google Patents

Description

K J. PRICE' EVAPORATOR Feb. s, 19,21.

Filed Jltlne l2, 1923 i1 ilaiaeniedv Feb. is, .192i o UNITED `.swf-rus JOSEPH PRICE,

PATENT OFFICE.

or NEW YORK, N. Y., AssIeNoR To THE erRIscoiu-Russnian COMPANY, l

or NEW YORK, N. Y.,'A. CORPORATION or nELAwAmaz;y

' RvAPoRAToR.

Appliation ma June l12, 1923. serial No; 644,971.

The present invention relates to evaporators of the type employed to produce purified lboiler feed-water from water containing scale-forming" impurities and has to d o l 5 primarily with the lcpnstruction of the heat# ing element and its assembly in the evapora- OI. r

Y The heat for vaporizing the liquid in evap- .orators is usually derived from steam admitted to heat transferring coils lor tubes arranged within the evaporator shell and extending into the. liquid to be evaporated. In cases where the heating element is vmadeup of vstraightv tubes the tubes are usually arranged in substantial parallelism to constitute a unitary bundle comprising `tube sheets inthe ends of the bundle. The

' tube ends are expanded or otherwise iixedly "secured in the tube sheets. The tube bundle 29 is then submerged or partly submerged in the liquid within the shell and heating steam supplied to the tube Abundle to maintainthe liquid in va state of constant ebullition and thereby' effect the desired evaporation. During4 the vaporizing process a portion of the scale-forming impurities in the liquid precipitate out andl to a certain extent collect on the surfacesof the heating tubes in the form of a hard sealy deposit. In the co-4 30 ending application, Serial No. 501,058, liled gept. 16,1921, in the name of Russell C. Jones andassigned to the assignee of this I application, there is shown an eva orator j of this general type employing inits eating :x5 element tubes which are slightly bowedfor the purpose of ycracking oft and loosening accumulated scale. Upon changes in -temperature these bowed tubes will flex and' in this manner crack andloosen the scaly de# 40 posit which has been precipitated on them.

The present invention is conceived .particularly as an improvement over the type of vapparatus disclosed in the above mentioned copending application, but it is applicable- .215 not only to an apparatus embodying a heat' ingelement employing bowed tubes, but is applicable as well to any apparatus having a heating element which consists of a bundle of closely grouped tubes which in the course of operation are likely to requirecleaning or otherwise need attention.

Evaporators employing a Vheating element consisting of a large number of closely` grouped tubes' are open tothe objection that the tubes of the bundle are relatively inaccessible for purposes of cleaningor repair.

In evaporators employing a tube bundle con-l sisting of straight tubes circular in cross section scale` accumulates rapidly and frequent removal of this scale is required. Due to temperature changes the tubes exert a slight cracking' action on the scale due toa difeol ference between the temperature coeilicient i of the -metal of the tubes and that of the',-

scale deposit, but this action is entirely -infact that a heating element of this type is extremely diiiicult to handle without danger of-injury. To obtain access to the tubes the operator must enter the shell, and his difficulty in vgetting at the heating surfaces is readily apparent. Even if the entire bundle were withdrawn from the shell the innerv tubes of the bundle would, nevertheless, be diiiicult of access. l v

It is a 'principal object of this invention vto provide an apparatus employing a tube bundle'consisting of a plurality of closely grouped tubes arranged in substantial parallelismiof such construction that the heating ele'ment is readily removable fromthe shell and, easyk access is provided tof every tube ofthe bundle.

It is also an object to providev an evaporator wherein/bowed tubes or tubes otherwise `deformed for facilitating scale removal A may be employed and` may be grouped into acompact tube bundle which permits of ready 4removal Aand at the same time provides for easy access to each tube 'of the-M heating element. Y

The lpresent invention contemplates an apparatus' employing a tube bundle built in sections. The bundle consists [of a number ofclosely grouped substantially parallel tubes having their ends securelyfsupported in suitable tube sheets, which tube sheets are maintained rigidly spaced -in `case a bowed tube construction for scale removal is desped. when assembledin the than the haa-l ing element is substantially the same in all respects as a unitary tube bundle of this type. vLikewise the entire1 apparatus presents substantially the same .appearance as the ordinary evaporator of this type and is identical in operation.

In carrying out my invention I preferably construct the tube sheets in sections` each section supporting one or more rows of tubes extending across the tube bundle. `spondlng tube sheet section is lprovided at the opposite end of the apparatus, so that A correthe two sections with theu tubes which they support constitute a removable element which may be withdrawn bodily from the evaporatorv shell. I prefer to employ one 0rtwo rows of tubes 1n each section of the heating element for the reason that with this construction every tube will'` be readily acremoved from the shell.

, Fig. l'is a sectional elevational view illus? trating an apparatus embodying my invention;

Fig. 2 is centrally of the apparatus;

. the cover ofthe apparatus removed, showing- .the heating'elelnent' in position;

:Fig: 3 is a front elevational view with Fig. 4'is a similar view takenfrom the `lback of the apparatus;

' Figs. 5 and 6 are a partial sectional viewl and a front elevational view respectively 'of one section of the heating element;

Figs. 7 an, v8 are partial views' showing the construction of the -inlet and discharge manifolds;

Figs. 9 and 10 are views similar respectively to Figs. 5 and 6 showing the rear end of a section of the heating element; and

Fig. 11 is an end view of a section of the heating element illustrating, a modified con` struction.

4Referring to the drawings, v1 indicates t-he containing shell of the evaporator and.

2` indicates 'the bundle of heating tubes disposed within the shell. Steam is supvplied to the tubes 2 through a suitable inlet opening 3 and -after being condensed in its passage through the tubes 2 is returned through a drain line 4 and discharged at the outlet 5 provided for .the purpose. The

vapor generated in the 4evaporator shell proceeds upward through the baiiie plates Gand separator 7 and is passed out of the a transverse sectional view taken fective exfo apparatus 'through the lopening 8. A trough-shaped baiile 9 is preferably provided to cover the upper. portion 'of the tube bundle andextend down beneath the surface of the liquid at the sides of the. bundle as indicated in Figure 2 for the pur- .pose of minimizing -the agitation. ofthe liquid in the shell produced by ebullition. The shell -1 is provided with a removable cover 10 which affords access to the interior of the apparatus. V

The tubes f2 of the heating element may they may be deformed in such fashion vthat their surfaces will flex upon the changes'in temperature to thereby remove accumulated scale. I have here shown the tubes slightly bowed. so that the middle portion of each tube isdisplaced a short distance out of a straight line connecting its ends. The ends of the tubes are iiXedlyv supported in suitable tube sheets 11 and these tube sheets arel maintained against relative displacement by stayrods 12 at the top of the tube bundle and by the tube 4 at the bottom of the bundle which serves as a stay-tube 'as well as a dischargepassage for the condensate. Upon increase in temperaturether'e? fore, longitudinal expansion of the tubes 2 will produce a flexure of the tubes and the -be straight tubes of circular cross section or extent to which vthe tubes are bowedwill vary depending upon their temperature.

By successively introducing into the tubes a quantity o-f hot steamv and a vquantity of cold water a marked' eXuI'e ofthe tube surd faces is obta'ned and a correspondingly ef- Alkation of the accumulated scale accomplished. l 1

The tube bundle constituting the heating element of the 7ippar'at'us is builtin sections.

' I have here illustrated each section of the heating element as comprising two vertical.'

rows of tubes extending across. the height of the tube bundle. is a completeunitin itself and receives its quota of heating steam, condenses the steam Each of these se;tions.

during' its passage along the lengthv of the p apparatus, and is .provided with its individual return tube v4 for conveying the condensate back to the discharge outlet. vThe construction of the improved tube bundle sections ,is particularly shown in Figs. 5 and 6. The front end of the section comprises a chamber 13 for receiving the heating steam.l This chamber is directly in comnnlnication with the inlet ends of the tubes 2 and thus serves to supply the tubes constituting this particular section. The outlet ends of the tubes of the section discharge into a chamber 14 (Fig. 9) provided at the rear of the tube bundlesection. The

chamber 14 is also in communicationy with the inlety end of the drain tube 4 and serves to receive the condensate issuing from the tubes 2 and to pass it along into` the tube 4,

niarhosi whence it iis again conveyed dewn v the length of the apparatus and emptied into the discharge chamber (Fig. 5) which is.

provided in the front end of` the tube bundle section. l

For the purpose of affording access to the tube ends holes are made iii the outer walls of each headerl in register with the respective tubes of the bundle. Atool for alixing the tubes in the tube sheet may Le inserted through these holes and likewise a cleaning tool may be introduced to` remove deposits from the interior of the tubes.

Each hole is tapped and is provided with a suitable plug 23 to render the chamber liquid tight during operation of the ap-.

paratu's. y

From the showing in Fig. 1 it willbe noted that when the tube bundle sections are assembled in the shell the appearance of the heating elementiis not essentially different from that of a. heating element of this type constructed as a unitary bundle.

Likewise the operation and attention re-. D quired are in all respects similar to that of the usual evaporator of'tliis type. Each of the individual tube bundle sections slides on a track 16, as best shown in Figs. 2 and 10. These tracks are here shown as angle irons extending longitudinally ofthe emp- Vorator shell and spaced to support the individual tube bundle sections 1n proper relative' position. A

' At the front end of the tube bundle an inlet manifold 17 extends transversely of" the shell and serves to supply the sections of the tube bundle with heating steam. The

manifold is rigidly associated with the apparatus shell, and each ofthe individual tube bundle sections is bolted'to it for support,I as indicated at 18. When thus secured in position the inlet openings in the respec-` tive tube bundle sections lie in register with the corresponding Yopenings 19 provided on the inlet manifold. In order to further se-l cure the individual tube bundle sections, and to maintainl them in fixed relation, provision is made for inserting a long bolt20 betweenadjacent sections, which bolt cari'ies a dog or bracket 2l, designed to bridge over on to adjacent sections and thus lend rigidity to the structure. Similarly, at the lower side of the tube bundle sections a discharge manifold 22 is provided andifacilities are furnished for 'attachment to"this manifold in the same manner as` attachment to the upper manifold is accomplished.

To remove the individual sections of the heating element from the lshell it is merely necessary to remove the bolts serving to support it and then withdraw the section bodily through the open end of the shell.v

Any desired one of the tubl bundle sections may be withdrawn or any'number of them may be positioned at .the exterior of the shell'at one time. It is thus levident that i complete and ready access to 'any tube off'- the bundle is possible.` Individual sections employing two rows of tubes as -above de-y scribed permit of ready access to each tube but if desired these sections may consist o only one row oftubes, as shown Lin Fig. 11.' Y Similarly, any desired number of rows of.

tubes maybe included in eachJ section. l'I

prefer to have eachl section extend vertically of the bundle as shown, although it'would be possible to arrange each tube section to include a horizontal'- row of tubes if desired.. The vertical arrangement is preferred, however, due to easeof removal and general convenience in handling.

bodiment of my invention, it is to be under- While I have illustrated a preferred emstood that certain changes and modifications may be made withinthe scope of the appended claims. 7

v Iclaim:

1. An evaporator for producing vapor from liquid containing' scaleimpurities comprising a shell for containing the liquid, a heating element consisting of purified orming a plurality of independently removable sec-` tions, each of said sections comprising headers at the respective ends thereof, a plurality of slightly bowed heat transferring tubes extending betweensaid headers, and means forming a part of each section for spacing' the respective headers a fixed distance from one-another irrespective of expansion and contraction of saidv tubes, the extent of the bowing of said tubes awayv from a straight axial line being suicint to prevent rupture JOD under A`expansion vand contraction, but not i combination of a vessel, a heating element f therein consisting ofa plurality ofinde- -pendently`removable sections, eachof said sections comprising a vplurality of heat transferring tubes arranged in substantial parallelism, tube sheets supportingthe ends i of said tubes, said tubes and tube sheets being removable asa unit from the vvessel independently of the remainin sectionsv of the heating element, lal tie-bo t extending between the upper ortions of the-respec- \tive tube sheets. andJ stantial dimensions extending between the lower portions of the tube sheets, said tiea drain tube of subbolt and drain tube maintaining the tube sheets against free relative movementunder the expansion and contraction of the heat-f' ing tubes, said heating 'tubes bein away from a straight axial line v bowed ciently to prevent rupture but 'not' sufficiently to prevent a substantial exfoliation of the sealy deposit of impurities accumulated on the tubes by bending orstraightening of the tubes under change in temperature.

3.l In an evaporator, the combination of a shell 'for' the liquid to be evaporated having a detachable portion at one end lto give access to its interior, a heating element consisting'of a plurality of independentlyre-v movable sections each section comprising a pair of tube sheets having a plurality of 'heating tubes 'extending therebetween, said tubes'being arranged in substantial Aparallelism along their entirefle'g'th, and means forming a part of :each of said removable sections for maintaining said tube sheets against free relative movement under the expansion and contraction/of lsaid tubes,

said tubes being bowed away from a straight axial line suiiiciently to prevent rupture but 7 not suiiiciently to prevent a substantial exfoliation of the sealy deposit of impurities -accumulated ,on the tubes by bending or straightening of the tubes under change 1n temperature.

' 4. In an apparatus ing liquids' involving the deposit-of scaleforming materials, the-l combination of a vessel, a removable heating element therein consisting of a `plurality of independently removable sections each' comprising a pair of tube sheets having heat-transferring tubes extending therebetween and `arranged in substantial parallelism, said tubes being slightlyoifset at their middlel portions, the extent of suchoi'set being just sufficient for elongation of the tubes through heat expanv' sion to produce a further bowing ofthe tube instead of rupture, and means Vforming a part of each removable section for holding said tube `sheets against the thrust occasioned'by the elongation of said-tubes.

, .5,-In an evaporator, the, combination of a-shell `for the liquid to be evaporated havv- .ing a detachable portion at one end to give,

f access to thev interior, a heating -unit Within saidfshell consisting of a .pluralityof heat,`

'transferring elements constituting 'separate independently removable sections of lthe said heating unit, each ofsaid separate sections being slidable horizontally to and` from its operative position Within the shell,

and yeach having a header provided withl p vertical joint faces havinglopenings for revfor heating and treat-l ceiving and discharging Working fluid, in-` let and `discharge manifolds. provided on said shell havingv a plurality of openings spaced'to correspond with the positioning'.

of said respective independently removable heat transferring sections, sald manifolds having vertical joint. faces positioned to coact with the joint faces of the several sectlonsand serving as stops toiarrest the movement of said sections in then-,operative position as they are slid into said shell, and

-which the opposite ends. of the tubes are supported, a header associated With the front tube sheet havinginlet and outlet joint surfaces at right angles tofthe axis of the heating section, said inlet communicating l.

with a large portion ofthe tubes of the section Aand said outlet communicating with those tubes not in communication With said inlet, and achamber at the other end of the removable heating section in communication with Aall of said tubes, an intake passage providedy on said shell for conveying heating Huid to the apparatus, a discharge passage on' the shell for receiving Huid discharged from the apparatus. intake and discharge manifolds secured to the interior of the shell and in communication respectively' vwlth said mtake and discharge passages, a

plurality of rails ivithin the shell upon which each of said, independently removable s ctions respectivelyl is slida'ble to and -from i s operative posi-tion', said manifolds having joint surfaces positioned in horizontal alignment with the'joint Vsurfaces on the heatlng section headers when said sections are supported on` said rails/ and the'y planes of the joint surfaces of said manifolds being disposed so as to contactjyvith, the joint sur-YA faces of the heades when 'the heating sections are slid intoitheir `operative positions within thel shell. 'l

In testimony rwhereof-I aiiix my' signature.' l

' /4 f 'Josera inron.

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