US3160571A

US3160571A - Evaporator construction

Info

Publication number: US3160571A
Application number: US139411A
Authority: US
Inventors: Stewart F Mulford; Darreil G Durst
Original assignee: Baldwin Lima Hamilton Corp
Current assignee: Baldwin Lima Hamilton Corp
Priority date: 1961-09-20
Filing date: 1961-09-20
Publication date: 1964-12-08
Anticipated expiration: 1981-12-08

Description

Dec. 8, 1964 s. F. MULFORD ETAL 3,160,571

EVAPORATOR CONSTRUCTION Filed Sept. 20, 1961 4 Sheets-Sheet 2 INVENTORS 95mm, MWXc W ATTORNEYS 1964 s. F. MULFORD ETAL 3,160,571

EVAPORATOR CONSTRUCTION 4 Sheets-Sheet 3 Filed Sept. 20, 1961 ATTORNEYS 1964 s. F. MULFORD ETAL 3,160,571

EVAPORATOR CONSTRUCTION Filed Sept. 20, 1961 4 Sheets-Sheet 4 INVENTORS SewarfiEMzl/lfizd y Dan'ell GZDwrsfi (z United States Patent sueasn EVAEORATQR (IONSIRUQTIQN tewart F. Muiford, w Diego, Qalii, and Darreil G. Durst, Massillom'fihio, assignors, by mesne assignments, to Baldwin-Lima-Hamilton Corporation, Philadelphia, Pin, a corporation of Pennsylvania Filed Sept. 29, 1961, Ser. No. 139,411 8 tllaims. (Cl. 2tl2-173) tors have been provided making use of various different types of feed-water devices, that is, the devices through which the sea water, brine or other liquid to be distilled, is introduced into the particular evaporator chamber. In all flash evaporators, of course, the liquid to be distilled is introduced through a feed-water device into a chamber having an internal chamber pressure below the saturation pressure of the liquid at the particular temperature of the liquid, whereby a certain portion of the liquid flashes into vapor with such vapor subsequently being condensed to produce the desired distillate.

In most cases, where a high degree of purity is required in the final distillate, it is necessary to pass the vapors flashed from the liquid in each evaporator chamber through a vapor separator or eliminator, prior to the condensing of these vapors. which might be entrained in the vapor are removed, which droplets would normally carry a certain amount of the impurities with the vapor and into the final distillate.

In the continued development of flash distillation plants, it is the common goal to produce a distillation plant of the lowest overall cost, both in original fabrication and construction, as well as in operation thereof.

It is known that a major advance toward the production of an optimum flash distillation plant can be made by improving the feed-water device or devices of the present flash distillation plants, and it is principally to this end that the improvements of the present invention are directed.

Improvement of the feedwater devices for flash distillation plants does not necessarily require that these feedwater devices be of a construction having a lower cost than the prior feedwater devices, although minimum costs are desirable. For instance, even though an improved feedwater device might be of higher cost than prior feedwater devices, it is very possible, through an improved manner of introduction of the liquid to be distillated into the evaporator chamber, that the further vapor separator normally required might be eliminated, and through this or by virtue of other resulting improved operating conditions, a reduction in size of the evaporator chambers might be made providing an appreciable savings in cost of the overall flash evaporator plant.

A further factor to be considered is that evaporator plants are required for many varied uses and many varied conditions, all of which require a variation in design of the flash distillation plant for the use and conditions involved. Any improved feedwater device, therefore, must In this manner, liquid droplets 3,160,571 Patented Dec. 8, 1964 be applicable to a variety of conditions and a variety of configurations of flash evaporator plants so that the optimum advantages thereof can be obtained.

In the improvement of feedwater devices for flash evaporator plants, many further factors, including certain of those developed by practical experience through the design and use of prior evaporator plants, must be considered.

One such factor to be considered is that vaporization or flashing of the liquid in a fllash evaporator chamber tends to be localized at a point or plane where the pressure is reduced below saturation pressure. Thus, distribution of the liquid by the feed-water device must be accomplished, and particularly at the area of vaporization, by spreading out as much as possible the inflowing stream of liquid to be evaporated and in this manner a maximum of vaporization can be accomplished.

A further factor to consider, and particularly if the necessity of using vapor separators in the evaporator chambers is to be eliminated or minimized, while still accomplishing the same degree or an improved degree of purity of the final distillate, is that the feedwater device should be such as to eliminate the maximum amount of water droplets or entrained fog from the vapors, to thereby accomplish within the feedwater device, the same general function of the normal additional vapor separator.

- It is known from the art of vapor separators that two factors to this end, that is, the elimination of water droplets from the vapor, are important if such is to be accomplished.

First, advantage can be taken of the tendency of water to adhere to solid surfaces so that if the vapor, as it flashes from the liquid, can be required to impinge or flow around and over solid surfaces, a certain amount of the water droplets can be eliminated. Secondly, it is known that by forcing the vapor to move in circuitous or tortuous paths, a great amount of turbulence is created therein which again will serve to release Water droplets from the vapor.

It is, therefore, a general object of the present invention to provide an improved feedwater device construction for flash evaporatcrs which eliminates the foregoing problems and incorporates advantages of the foregoing principles. 7

It is a primary object of the present invention to provide an improved feedwater device construction for flash evaporators which produces vapors within the flash chambers of a high degree of purity, to thereby eliminate in many cases, the necessity of providing the additional vapor separators for accomplishing a desired degree of purity, and in other cases, where vapor separators are used, to provide a higher degree of purity for the final distillate than has heretofore been possible.

It is a further object of the present invention to provide an improved feedwater device construction for flash evaporators which produces a maximum release of vapors within any given flash evaporator stage and a greater proportionate amount than has been heretofore possible,

in flash evaporators.

It is still a further object of the present invention to provide an improved feedwater device construction for flash evaporators which accomplishes the maximum elimination of water droplets from the vapors directly within the feedwater device.

it is an additional object of the present invention to provide an improved feedwater device construction for flash evaporators which may be adapted for use in a variety of different sizes and configurations of flash evaporators and will operate with maximum of efficiency therein.

Finally, it is an object of the present invention to provide an improved feedwater device construction for flash evaporators which, through increased efiiciency, makes possible the production of distillate of a maximum purity at a minimum cost of original fabrication and construction of the flash evaporators, as well as the operation thereof.

These and o her objects are accomplished by the parts, constructions, arrangements, combinations and subcombinations comprising the present invention, the nature of which is set forth in the following general statement, preferred embodiments of which-illustrative of the best modes in which applicants have contemplated applying the principlesare set forth in the following description and illustrated in the accompanying drawings, and which are particularly and distinctly pointed out and set forth in the appended claims forming a part hereof.

In general terms, the improvements in evaporator construction comprising the present invention may be stated as being a part of a flash evaporator chamber having an internal pressure lower than the saturation pressure of the liquid to be distilled at the particular temperature of the liquid and being formed of a feedwater portion and a condensing portion, whereby the liquid to be distilled is introduced into and flows through the chamber in the feedwater portion and the vapors flashed therefrom are condensed in the condensing portion, with the resulting distillate being collected from this condensing portion.

The condensing portion may be of usual construction with means for condensing the flashed vapors and means for collecting the resulting distillate, with the improvements of the present invention residing specifically in the feedwater portion and the combination thereof with the remainder of the chamber.

In broad terms, the feedwater portion is comprised of a bed of aggregate-like material, preferably having a generally horizontal length and a covered top portion, with this bed being supported in the chamber feedwater portion above any static liquid level therein. The liquid to be distilled, such as sea water and the like, is introduced into the chamber and is preferably distributed generally horizontally throughout the length of the bed, with at least the major portion passing generally horizontally through the bed, and with this liquid and any resulting flashed vapors discharging through the bed, horizontally or otherwise. The vapors flashed from the liquid within the bed and within the chamber are, of course,'received and condensed by the condensing portion to provide the desired distillate.

By way of example, embodiments of the improved evaporator construction of the present invention are illustrated in the accompanying drawings forming a part hereof, wherein like numerals indicate similar parts throng out the several views, and in which;

FIG. 1 is a side elevation, with parts broken away and in section to show certain interior construction thereof, of an evaporator shell containing three flash evaporator chambers constructed according to one embodiment of the present invention;

FIG. 2 a vertical section through one of the flash evaporator chambers of FIG. 1, looking in the direction of the arrows Z2 in FIG. 1 and with the condensing portion of the chamber illustrated somewhat schematically;

FIG. 3 a fragmentary horizontal section, part in elevation and with parts broken away, through one of the hash evaporator chambers of FIG. 1, looking in the direction of the arrows 33 in FIG. 1;

FIG. 4 an enlarged fragmentary vertical sectional view, part in elevation, looking in the direction of the arrows 44 in FIG. 1;

ti- 5 in FIG. 1;

1G. 7 an enlarged fragmentary vertical sectional view, part in elevation, looking in the direction of the arrows 7-7 in PEG. 1;

FIG. 8 a fragmentary side elevation, with parts broken away and in section, of a flash evaporator chamber showing certain details of the feedwater portion of a second embodiment of the present invention;

FIG. 9 a top plan view of the feedwater distribution box of the flash evaporator chamber of FIG. 8, looking in the direction of the arrows 9-9 in FIG. 8;

FIG. 10 a vertical sectional view, part in elevation, of the feedwater box of FIG. 9 and looking in the direction of the arrows 10-10 in FIG. 8;

FIG. 11 a perspective view, with parts broken away and in section, of the feedwater box of the flash chamber of FIG. 8;

FIG. 12 a side elevation, with parts broken away and in section showing the feedwater portion in detail, of a flash evaporator chamber illustrating a third embodiment of the present invention;

FIG. 13 a fragmentary top plan view, with parts broken away, showing the feedwater box of the flash evaporator chamber of FIG. 12 and looking in the direction of the rrows 13-13 in FIG. 12;

FIG. 14 a fragmentary vertical sectional view, part in elevation, looking in the direction of the arrows 14 14 in FIG. 13; and,

FIG. 15 a fragmentary perspective view, with parts broken away and in section, of the feedwater box of the flash evaporator chamber of FIG. 12.

The first embodiment of the present invention is illustrated in FIGS. 1 through 7, and as shown in FIG. 1, includes an evaporator shell, generally indicated at 29, having a series of three separate flash evaporator chambers, generally indicated at 21, formed therein. Each evaporator chamber 21 is comprised of a weedwater portion, generally indicated at 22, and a condensing portion, generally indicated at 23, with all of the chambers 21 being substantially the same so that a description of one will provide a complete understanding of all of these chambers.

The condensing portions 23 of the chambers 21 may be of any usual construction and are illustrated somewhat schematically in FIG. 2. As shown, each condensing portion 23 may include the condensing tubes 24 and the distillate-collecting member 25 having the distillate drain 26. Furthermore, these condensing portions 23 may, under certain circumstances to be discussed hereinafter in detail, be provided with a vapor separator 27.

The improvements of the present invention reside principally in the feedwater portions 22 and the condensing portions 23 do not form a part of the present invention other than in the overall combination to form complete an doperable evaporator chambers.

Each of the feedwater portions 22 is formed by a series of laterally spaced and longitudinally extending feed- Water boxes, generally indicated at 28, with the entrance end 29 of these boxes 28 in the first chamber 21, or the chamber to the left as shown in FIG. 1, being connected through a box vertical end plate 30 and a chamber inlet horizontal top plate 31 to the shell end plate 32, above the shell inlet opening 33.

The longitudinally opposite closed ends, generally indicated at 34, of these boxes 28 are closed by a box end plate 35 which extends vertically and completely laterally across the shell 20, secured to the shell bottom wall 36. Furthermore, the box end plate 35 of the feedwater boxes 28 in this first chamber is spaced longitudinally from the vertical division plate 37 between this first chamber --and the second chamber, with division plate having the opening 38 formed therein providing feedwater communication between the first and second chambers of shell 20.

As shown particularly in FIGS. 2 and 3, both the box end plate 30 and the chamber inlet top plate 31 extend completely laterally across the shell 24? with the lower edge 39 of end plate 36 being spaced considerably above the shell bottom wall 36. Thus, in view of the positioning and configuration of the box end plate 3t), chamber inlet top plate 31 and box end plate 35, the only communication from the shell inlet opening 33 into the inner confines of the chamber 21 above the feedwater boxes 23 is through these boxes. Furthermore, the box end plate 30 and inlet top plate 31 form a chamber 4%) completely laterally across the shell 28 providing a part of the feedwater distribution to each of the boxes 28.

In each of the chambers 21 of the particulm embodiment shown in FIGS. 1 through 7, there are four longitudinally extending and laterally spaced intermediate boxes 23 formed completely Within the particular chmber 21, and at either side there is a side box 28 formed partially by the shell bottom wall as. Each of the intermediate boxes 23 is formed with longitudinally extending laterally spaced side walls 41 so that these side walls of any particular intermm'iate box 28 are laterally spaced at the lower edges 42 thereof, and opposed side walls 41 of adjacent intermediate boxes 28 are integrally connected by the bottom walls 43.

The upper edges 44 of side walls 41 extend substantially horizontally with the lower edges 42 extending angularly downwardly from the inlet end of the chamber to the outlet end thereof, or from the left to the right as shown in FIG. 1, so that the bottom walls 43 are positioned likewise downwardly angled. Thus, the side walls 41 are of minimum vertical dimension at the box end plate 36 or the inlet end of the chamber spaced :1 maximum distance above the shell bottom wall and these side walls increase in verticfl dimension progressively toward the box end plate 35 or the outlet end of the chamber, nearly approaching the shell bottom wall 36.

As shown in FIGS. 4 through 7, the two side boxes 28 only have the single side wall 41 with the other side of these boxes being formed by the shell bottom wall 36. Furthermore, the side walls 41 of these side boxes, as they increase in vertical dimension, ultimately abut the shell bottom wall 36 intermediate the length of these boxes, as does a portion of the bottom wall 43 connecting the side walls of these side boxes to the side wall 41 of the next laterally adjacent intermediate box, best seen in FIGS. 5 and 6.

Each set of side walls 41 forming a particular intermediate box 28 are formed at their upper edges 44 with laterally outwardly extending flanges 45 so that these flanges are directed toward the laterally adjacent boxes at either side of the particular box. The flanges 45 at the upper edge of the side wall 41 of each of the side boxes 28 is likewise directed laterally toward the laterally adjacent boxes 28, or away from the shell bottom wall 36 forming the other sides of these side boxes 23.

Spaced above the side wall upper edges 44 and flanges 45 and extending substantially parallel thereto, are the box covers 46, with the covers of the intermediate boxes 23 extending laterally completely over the particular box and vertically aligned with the edges of the flanges 45 of the box side walls. The covers 46 of the side boxes 28 extend in the same manner completely across the particular box, but are secured at the one side to the shell side wall 36, as shown in FIGS. 5 and 6.

The longitudinally extending edges 47 of the box covers 46 may be downwardly flanged, as shown. It is pre ferred, however, that the flanges 45 on the side wall upper edges 44 merely terminate horizontally to present a plain horizontal surface, for reasons to be hereinafter described.

The ends of all of the box side walls 41, bottom walls 43 and covers 46 are'secured to and supported by the box end plate 30 at one end and the box end plate 35 at the other end. Thus, the bottom walls 43 are positioned downwardly angled extending from a maximum height at the end plate 30 to a minimum height nearly against the shell bottom wall 36 at the end plate 35, while the upper edges 44 of the side walls 41 extend susbtantially horizontal and the box covers 46 are spaced and extend substantially horizontally thereabove.

Packed beds 48 of aggregate-like material are positioned extending vertically between the side wall flanges 45 and the edges of the box covers 46 within the downwardly flanged edges 47 of these covers 46, and these beds 48 are enclosed laterally by vertically extending layers of wire mesh 49, which may be expanded metal or the like. These beds 48 and their wire mesh enclosures 49 extend the entire longitudinal distance of the boxes 28 totally between the

end plates

30 and 35.

Thus, the intermediate boxes 28 are provided with laterally opposed beds 43 at the laterally opposed sides thereof above the side walls 41 and beneath the covers 46, and the side boxes 28 are provided with similarly positioned beds 48 at the sides thereof opposite from the shell bottom wall 36. Furthermore, these beds 48 form the only communication through the boxes 28 from the entrance end 29 of these boxes to the part of the chamber feed-water portion 22 above or outwardly of these boxes.

The beds 48 may be of various packed aggregate-like materials, such as crushed rock, Raschig rings, Berl saddles, or other such materials, whether manufactured, synthetic or natural materials. The prime requirement for this material is that it will form a packed aggregatelike material bed having voids between the particles thereof to permit the flow of liquids and vapors 'therethrough but at the same time requiring the liquids and vapors to travel in tortuous or circuitous paths.

The size and shape of the individual particles of the aggregate-like material maybe varied as the particular conditions demand. For instance, in the event a minimum of pressure drop in the liquid and vapor passing through the bed is required, an aggregate-like material may be used which, when packed to form the bed, has a greater ratio of voids to total volume, thereby minimizing the pressure drop therethrough.

As can be seen in FIG. 7, the box end plate 35 is formed to conform to that end of the boxes 28, covering the ends of the beds 48 and the ends of these boxes 28. Furthermore, between laterally adjacent boxes 28, this end plate 35 extends from the edge of the box bottom walls 43 downwardly to the shell bottom wall 36 so that this end plate seals the ends of the boxes but maintains the space laterally between the boxes and above the bottom walls 43 open upwardly.

Finally, in the first embodiment construction, the opening 38 is provided through the division plate 37 as previously described, providing feedwater communication between the first and second chambers, with a similar opening 5% being formed through the division plate 51 between the second and third chambers. As previously stated, the internal construction of the second and third chambers is similar to the first and these chambers operate in the same manner but at progressively lower temperatures and pressures. Also, a shell outlet opening 52 is provided from the third chamber, as shown.

In operation of the first embodiment construction, the feedwater or liquid to be distilled enters the first chamber through the shell inlet opening 33 and passes beneath the box end plate 30 into the space beneath the bottom walls 43 completely laterally across the shell 20 and the entire longitudinal length of the feed-water boxes 28 to the end plate 35. Thus, an inlet and distribution portion is provided for the feedwater boxes 28 which permits the feedwater to flow into these boxes and be distributed completely along the length thereof.

The feedwa-ter then passes upwardly between the box side walls 41 and generally horizontally through the packed beds 48 of aggregate-like material in a wide, and in this case, a relatively thin generally horizontal sheet, spilling downwardly over the bottom walls 43. During passage of this liquid through these beds 48 in the liquid is required to move in a tortuous path and impinges against the particles of aggregate-like material forming the beds 48.

In describing the passage of feedwater through the packed beds 48 of aggregate-like material the term relatively thin generally horizontal sheet is used. It should be understood, however, that according to the principles of the present invention, it is preferred that the beds,

Whether in this embodiment or other embodiments, are horizontally extended in order to provide the. maximum of horizontal distribution of the feedwater flow as space limitations will permit, but the vertical depth of flow will depend on the particular construction and the rate that the feedwater is introduced to the feedwater device.

Furthermore, the term sheet is not intended to indicate a true continuous sheet whether generally horizontal or otherwise, since the flow through the packed beds of aggregate-like material necessarily forces the feedwater through various tortuous paths so that the sheet is formed from these separate streams. Thus, these terms are used in a general sense and are intended to be thusly construed.

As in the usual construction of flash evaporators, the pressure within the particular chamber 21 is regulated such that it is below saturation pressure of the liquid at the particular temperature of the liquid as this liquid enters, so that as the liquid passes through the beds 48, this liquid is spread out into the broad horizontal sheet and the major portion of the vapors are released from the liquid within the beds 48. Thus, these vapors are likewise required to move in tortuous or circuitous paths around the particles of aggregate-like material forming the beds. In this manner, a large proportion of any droplets of liquid remaining in the vapor are removed from this vapor, which droplets otherwise would carry impurities with the vapor.

These vapors then rise upwardly into the condensing portion 23 of the particular chamber, passing through the vapor separator 27, if such is provided, and around the condensing tubes 24. By providing the condensing tubes 24 with afluid of lower temperature, these vapors are condensed, being collected in the distillate collecting member 25 and taken out of the chamber through the distillate drain 26.

The remaining liquid or feedwater spilling over onto the upper surfaces of the bottom walls 43 passes downwardly along the downwardly angled lengths of these bottom walls in the troughs formed by the box side walls 41 and these bottom walls below the beds 48. This feedwater then passes by the box end plate 35, through the opening 3 8 in the division plate 37, and into thesecond chamber 21.

The subsequent chambers operate in the same manner,

with the feedwater passing through the opening 59 of division plate 51 between the second and third chambers 21 and ultimately out through the shell outlet opening 52. The second and third chambers 21 are, of course, properly regulated in pressure to obtain a fiashing off of a certain amount of the feedwater into vapor despite the progressively decreasing temperature of this 'feedwater.

It is important, in order to gain the advantages of the present invention, that any static feedwater level in any chamber is below the beds 48 of aggregate-like material, in order that the vapors released within the beds 4-8 and immediately outwardly thereof from the feedwater will not be required to pass through any further feedwater. Furthermore, the purpose of providing the flanges 44 of the box side walls 41 horizontal to present substantially plain horizontal surfaces is so that there is absolutely no danger of a feedwater level being built up or maintained in the beds 43. This, therefore, insures that the vapors will not be forced to pass through a feedwater level after release from the feedwater.

It has been found that when the vapor is required to pass through the feedwater, this vapor tends to pick up additional droplets of the feedwater which can carry impurities with the vapor. Also, any foaming of the feedwater increased this water droplet pick-up tendency and in the present construction any foaming will occur on the bottom walls 43 after substantially all of the vapors have been released. n

Thus, with the first embodiment construction of the present invention, the feedwater is distributed to the feedwater boxes 28 and passes through the beds 48 of aggregate-like material. In view of the beds having considerable horizontal lengths and the feedwater is distributed horizontal sheet which provides the maximum of flashing of the vapors therefrom.

Furt iermore, these beds 48 are maintained above any static feedwater level in the chambers in order that the vapors flashed from the feedwater .will not be required to, pass through the feedwater, but rather the major portion of this vapor is released within the beds 48, so that a substantial portion of any water droplets carried by the vapors will be removed therefrom. The construction of the present invention might therefore be termed a dry flash device.

A still further advantage of the first embodiment construction, is the unique relationship between the inlet and distribution portion of the chamber feedwater portion 22 and the outlet portion thereof formed by the troughs over the box bottom walls 43. As described above, the inlet and distribution portion directly underlies the outlet portion, with the outlet portion being formed by the box side walls 41 and the downwardly angled bottom walls 43 which direct the flow to the exit end to the particular chamber.

By providing the inlet and outlet portions, one directly overlying the other, it is possible to provide a unit of maximum capacity, yet minimize size. Furthermore, due to the unique construction of these feedwater boxes 2'5 with the particular formation of beds 43, it is possible to properly handle this increased capacity and provide maxi mum vaporization therefrom.

This first embodiment construction has been illustrated with a vapor separator 27 in the condensing portion 23 but it is believed, due to the increased efiiciency of the feedwater boxes 28, that in many instances it is possible to completely eliminate the use of any such vapor separator. In cases, however, where it is desired to provide distillate of maximum purity, such a vapor separator should be used and in sucha case, it is believed that the present evaporator construction will provide distillate of a purity not heretofore possible with prior flash evaporator constructions. a

The second embodiment of the evaporator construction of the present invention is shown in FIGS. 8 through 11, and in this case, merely a single feeclwater box 123 is provided in each of the evaporator chambers 121. The condensing portion 123 of this evaporator construction may be the same as in the first embodiment, with the change occurring in the feedwater portion 122.

As shown, a division plate 137 is provided with an opening 138 at the lower portion thereof between this division plate and the shell bottom wall 136. A feedwatcr box bottom wall 143 is supported horizontally spaced above the shell bottom wall 136 within the chan ber 121, spaced longitudinally from the division plate T37 by a vertically extending box end plate 132 and an inlet top plate 131. The inlet top plate 131 extends laterally the entire width of the box bottom wall 143 and is secured to the division plate 137 above the opening 133 with the box end plate 132 likewise extending the full 9 lateral width of bottom wall 143 and being secured between inlet top plate 131 and bottom wall 143.

The box side walls 141 extend the complete longitudinal length of the box bottom wall 143 and are secured to the division plate 137 around opening 138 and the inlet top plate 131, as Well as the edges of the bottom Wall 143, to form a closed passage through opening 138 into chamher 121 beneath the box bottom wall 143. The box end plate 135 is secured laterally between the side walls 141, and between the shell bottom wall 136 and the box bottom wall 143, to thereby complete the enclosure of the lower portion of the feedwater box 128 within chamber 121.

A box cover 146 is positioned horizontally, spaced above the box bottom wall 143 and conforming in size to bottom wall 143. This cover 146 may have a downwardly flanged edge 14-7, but it is important, for reasons previously discussed with reference to the first embodiment construction, that the bottom Wall 143 will not be upwardly flan ed, but rather will present a plain horizontal edge.

A packed bed 143 of aggregate-like material, in the form of a rectangular annulus, is formed around the edge of the bottom wall 143 and cover 146, enclosed inwardly and outwardly by wire mesh material 149. Within the enclosure formed by the inner Wire mesh material 149, the bottom wall 143 is provided with a series of inlet holes 153 spaced longitudinally along bottom Wall 143 within this enclosure.

In operation of this second embodiment construction, the feedwater enters through the opening 133 of division plate 137, spreading out beneath the bottom wall 143 of the feedwater box 123. This feedwater then passes upwardly through the inlet holes 153 of bottom wall 143 and horizontally through the packed bed 143 of aggregate-like material, falling outwardly into the remainder of the chamber 121, completely around feedwater box 128. The portion of the feedwater which does not flash into vapor ultimately passes out of the chamber 121 into an adjacent like chamber.

In this second embodiment construction, the same action takes place as previously described relative to the first embodiment construction, that is, the major portion of the vapors are released from the feedwater within the bed 148 and pass through the bed around the particles of aggregate therein, thereby removing a large percentage of the water droplets from this vapor.

It is again irnportant in this second embodiment construc ion, that any static feedwater level within the chamber 121 will not be above the packed bed 148 of aggregate like material for the reasons previously discussed.

Thus, in this second embodiment construction, an inlet and distribution portion is provided which properly distributes feedwater throughout the length of the bed 148. This again spreads out the feedwater in a wide, relatively thin, generally horizontal sheet to obtain a maximum of flashing or evaporation therefrom.

The third embodiment of the evaporator construction of the present invention is shown in FIGS. 12 through 15 and, in this case, only a single chamber 221 is shown within a single shell 220. Again, however, the condensing portion 223 may be substantially the same as in the prior embodiments, with the feedwater portion 222 being provided with a single feedwater box 228.

The feedwater inlet opening 238 is provided through the shell bottom Wall 236 with the inlet portion of the box 222 being formed by the

vertical end plates

232 and 235, and side walls 241, all connected vertically between the shell bottom wall 236 and the box bottom wall 243. The box bottom wall 243 is provided with a rectangular opening 254 therethrough, spaced longitudinally from the

end plates

232 and 235, and spaced laterally from the side walls 241. Thus, the only communication from the feedwater inlet opening 238 into the major portion of cham- 16 her 221 is through this opening 254 in the box bottom wall 243.

Supported spaced downwardly from the box bottom wall 243 by a series of connecting lugs 255 is a baffle 256 which is of slightly larger dimensions than the shell feedwater inlet opening 238 and is substantially vertically aligned therewith. This prevents feedwater entering the box 222 through the shell inlet opening 238 from passing directly through the opening 254 of the box bottom wall 243, but rather requires this feedwater to distribute throughout the [inlet portion of the box below the bottom wall 243 and pass through opening 254 throughout the extent thereof.

A piece of wire mesh material 257 is secured over the opening 254 in the box bottom wall 243, and a horizontally extending box cover 246 is positioned spaced above bottom wall 243, with a packed bed 248 of aggregate-like material being positioned between cover 246 and bottom Wall 243 and being enclosed at the box side walls 241 by the wire mesh material 249. Thus, in this third embodiment construction, the packed bed 248 of aggregate-like material extends completely over the box bottom wall 243 and, as in the second embodiment, is open through the wire mesh material 249 completely around the box 228.

The operation of this third embodiment construction is substantially the same as the first two embodiments, with the most important feature being that the feedwater is distributed throughout the packed bed 248 of aggregatelike material and is therefore in a relatively thin, wide; generally horizontal sheet for maximum evaporation. Furthermore, in this third embodiment construction, it is again important that any static feedwater level in the chamber 221 will be below this bed 243, in order that the maximum results may be obtained as hereinbefore discussed.

This third embodiment construction varies from the first two embodiments in the respect that the packed bed 248 completely covers the box bottom wall 243 and, therefore, the feedwater is forced to first pass upwardly through bed 248 and then generally horizontally through and out of this bed. This particular form of construction is particularly advantageous where minimum feedwater flow conditions might be encountered, since, even though r the flow of feedwater is slight, this feedwater must pass through an appreciable amount of aggregate-like material in View of the flow being required first generally vertically upwardly and then generally horizontally outwardly.

Thus, according to the principles of the present invention, as illustrated in the three embodiments shown, an improved 'feedwater device for flash evaporators is provided in which the feedwater is distributed throughout a considerable horizontal length and passes generally horizontally in a relatively thin, generally horizontal sheet through a bed or beds of packed aggregate-like material. In every case, thesebeds of aggregate-like material are maintained above any static feedwater level within the flash chambers and, therefore, constitute dry flash devices.

As a result of the beds of aggregate-like material being free of any immersion in the feedwater other than the generally horizontal sheet flowing therethrough, the major portion of the flashing of vapors from the feedwater taking place within the flash evaporator chamber takes place these beds. Thus, not only is maximum vaporization from the feedwater obtained due to the feedwater being introduced into the flash chamber in a relatively broad sheet, as well as the fact that the feedwater will move through the beds around the particles of aggregatelike material in tortuous or circuitous paths, but also the vapors released from the feedwater, since released within the bed, are likewise required to pass around the particles of aggregate-like material in similar tortuous or circuitous paths.

This flow or passage of the vapors through a portion of the bed will eliminate a large proportion of the water droplets normally carried by the vapor, which water droplets normally would carry impurities with the vapor. Furthermore, virtually all of the vaporization of the feedwater taking place within the particular flash chamber will have taken place prior to the feedwater striking or flowing over a surface outwardly of the feedwater device where foaming could occur. This, therefore, further eliminates the danger of the vapors picking up and carrying additional water droplets.

Additionally, in the first embodiment construction shown in FIGS. 1 through 7, a unique arrangement of parts is provided so that the inlet and distribution means for the feedwater to the feedwater devices or boxes is formed directly underlying the feedwater outlet means from the boxes. This, therefore, provides in this first embodiment construction, a maximum of compactness for a given feedwater capacity and permits a minimum shell size. Due to the improved operation of the unique feedwater box construction, however, this increased capacity is properly handled and provides a maximum of vaporization and a maximum of the final desired distillate having a high degree of purity not heretofore possible.

Still further, in the third embodiment construction shown in FIGS. 12 through 15, the feedwater flash device or box is constructed for providing, first, generally vertical flow of the'feed-water through a portion of the bed of aggregate-like material and then generally horizontally through this bed, in both cases in the relatively broad thin sheet. Thus, this third embodiment construction is particularly advantageous where minimumfeedwater flow conditions might be encountered, since even though there is a minimum of flow through the bed, the feedwater will always be required to pass through a relatively large amount of packed aggregate-like material.

The forms of feedwater devices in the three embodiments described in the foregoing are all provided with some form of top cover means 'over the bed or beds of aggregate-like material so that the feedwater, is forced to flow through the aggregate-like material in a generally horizontal direction and for at least a predetermined horizontal distance as determined by the particular construction involved. It is not intended, however, to limit the broad principles of the present invention to purely generally horizontal flow, although in many cases this will undoubtedly be preferred to insure that vapors released from the feedwater within the particular bed of aggregate-like material will be required to pass through a'certain portion of the bed for eliminating to the maximum extent possible water droplets therein as previously discussed.

Certain of the advantages of the present invention may be obtained, however, with a packed bed of aggregate-like material having no top'cover, wherein even a certain portion of the feedwater flow, although preferably widely generally horizontally distributed, might be through the top portion of the bed, and the vapors released might likewise flow upwardly through the top portion of the bed. In any case, however, it is important that the packed bed of aggregate-like material, whether covered or otherwise, will be positioned above any static feedwater level within the particular evaporator chamber and that the packed bed will be retained in such a manner that it is impossible for any static feedwater level to be maintained therein, whether the feedwater flow therethrough is purely generally horizontal or primarily generally horizontal with a portion thereof flowing generally vertically through the top portion of the bed.

Also, in the first embodiment shown and described for illustrating the principles of the present invention, a multi-stage evaporator construction is presented, and in the second and third embodiments merely single stages are presented. The principles of the present invention may be used in single or multi-stage constructions where 12 the advantages to be gained from the present invention are desirable, and in a multi-stage construction these principles may be incorporated in any stage or all the stages whether first, last or intermediate stages.

Although the term feedwater has been used in the foregoing description, it should be understood that, by the use of such term, it is not intended to restrict the present invention. This term feedwater is intended to include any liquid which it might be desired to distill, including sea water, brines or other liquids.

In the foreging description, certain terms have been used for brevity, clearness and understanding, but no unnecessary limitations are to be implied therefrom because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way of example and the scope of the present invention is not limited to the exact details of construction shown.

Having now described the invention, the construction, operation and use of preferred embodiments thereof, and the advantageous new and useful results obtained thereby, the new and useful construction and reasonable mechanical equivalents thereof obvious to those skilled in the art are set forth in the appended claims.

We claim:

1. Flash evaporator chamber construction for distilling sea water and the like including a feedwater portion and a condensing portion, feedwater inlet means for introducing liquid to be distilled into the feedwater portion and feedwater discharge means for discharging said liquid from the feedwater portion, bed means of aggregate-like material supported in the feedwater portion spaced above the feedwater discharge means and having at least one open discharge side spaced above the feedwater discharge means and opening generally horizontally into discharge liquid directing means in the feedwater portion, said bed open discharge side extending downwardly to substantially the lowest level of said bed means whereby it is impossible to maintain a static liquid level in said bed means, inlet liquid directing means formed in the feedwater portion operably connected to the feedwater inlet means and operably connected to the bed means space horizontally from said bed open discharge side for receiving liquid from the feedwater inlet means and directing said liquid to and horizontally through the bed means and horizontally from said bed open discharge side whereby at least part of the vapors released from the liquid within the feedwater portion will be released within the bed means and will pass through and out of the bed means above said liquid, the discharge liquid directing means formed in the feedwater portion extending downwardly from the bed open discharge side and operably connected to the feedwater discharge means for directing liquid from said bed open discharge side above any static liquid level in the discharge liquid directing means of the feedwater portion, and directing said liquid downwardly to said feedwater discharge means, means in the condensing portion for condensing vapors released from the liquid in the bed means and outwardly of the bed open discharge side, and means in the condensing portion for collecting the distillate resulting from the condensed vapors.

2. Flash evaporator chamber construction as defined in claim 1 in which a cover is formed in the feedwater portion overlying the bed means of aggregate-like material thereby forcing total horizontal discharge of liquid and vapor from the bed means.

3. Flash evaporator chamber construction as defined in claim 2 in which the bed means includes at least two spaced generally horizontal beds of aggregate-like material supported in the feedwater portion spaced above the feedwater discharge means having at least oppositely disposed open dischargesides spaced above the feedwater discharge means and opening in opposite direc- 3 13 tions generally horizontally into the discharge liquid directing means of the feedwater portion; in which each of said bed open discharge sides extends downwardly to substantially the lowest levels of said beds whereby it is impossible to maintain static liquid levels in said beds; in which the inlet liquid directing means is operably connected to each of said beds spaced horizontally from the open discharge sides of said beds for receiving liquid from the feedwater inlet means and directing said liquid to and simultaneously horizontally through each of the beds and horizontally from each of the bed open discharge sides; and in which the discharge liquid directing means extends downwardly from each of the bed open discharge sides to the feedwater discharge means. 4. Flash evaporator chamber construction as defined in claim 2 in which the bed means includes at least two spaced generally horizontal beds of aggregate-like material supported in the feedwater portion spaced above the feedwater discharge means having at least oppositely disposed open discharge sides spaced above the feedwater discharge means and opening in opposite directions generally horizontally into the discharge liquid directing means of the feedwater portion; in which each of said bed open discharge sides extends downwardly to substantially the lowest levels of said beds whereby it is impossible to maintain static liquid levels in said beds; in which the inlet liquid directing means is operably connected to each of said beds spaced horizontally from the open discharge sides of said beds for receiving liquids from the feedwater inlet means and directing said liquid to and simultaneously horizontally through each of the beds and horizontally from each of the bed open discharge sides; in which the discharge liquid directing means extends downwardly from each of the bed open discharge sides to the feedwater discharge means; in which a cover is positioned in the feedwater portion extending generally horizontally over the beds of aggregatelike material and horizontally between said beds thereby forcing total horizontal discharge of liquid and vapor from said beds; in which the discharge liquid directing means overlies a part of the inlet liquid directing means; and in which the discharge liquid directing means angles downwardly from beneath the bed open discharge sides to the feedwater discharge means for directing liquid discharging horizontally from the bed open discharge sides at a downward angle to the feedwater discharge means.

5. Flash evaporator chamber construction for distilling sea water and the like including a feedwater portion and a. condensing portion, feedwater inlet means for intro ducing liquid to be distilled into the feedwater portion and feedwater discharge means for discharging said liquid from the feedwater portion, at least one feedwater box mounted within the feedwater portion, bed means of aggregate-like material supported in the feedwater box spaced above the feedwater discharge means and having at least two oppositely disposed open discharge sides spaced above the feedwater discharge means and opening generally horizontally into discharge liquid directing means in the feedwater portion, said bed open discharge sides extending downwardly to substantially the lowest level of said bed means whereby it is impossible to maintain a static liquid level in said bed means, inlet liquid directing means formed in the feedwater portion at least partially below the bed means operably connected to the feedwater inlet means and operably connected through the feedwater box upwardly to the bed means spaced horizontally from each of said bed open discharge sides for receiving liquid from the feedwater inlet means and directing said liquid to and simultaneously horizontally in at least opposite directions through the bed means and horizontally from said bed open discharge sides whereby at least part of the vapors released from the liquid within the feedwater portion will be released within the bed means and will pass through and out of the bed means above said liquid, the discharge liquid directing means formed in the feedwater portion extending downwardly from each of the bed discharge sides and operably connected to the feedwater discharge means for directing liquid'from said bed open discharge sides above any static liquid directing means of the feedwater portion downwardly to said feedwater discharge means, means in the condensing portion for condensing vapors released from the liquid in the bed means and outwardly of the bed open discharge sides, and means in the condensing portion for collecting the distillate resulting from the condensed vapors.

6. Flash evaporator construction as defined in claim 5 in which the bed means has open discharge sides substantially completely around said bed means and opening generally horizontally into the discharge liquid directing means of the feedwater portion in substantially all horizontal directions from said bed means spaced above the feedwater discharge means; in which cover means is mounted on the feedwater box extending substantially horizontally over the entire bed means completely horizontally between said bed open discharge sides thereby forcing total horizontal discharge of liquid and vapor from the bed means; in which the inlet liquid directing means is operably connected to the bed means spaced horizontally from all of said bed open discharge sides for receiving liquid from the feedwater inlet means and directing said liquid to and horizontally in all directions through the bed means and horizontally in all directions from said bed open discharge sides; and in which the discharge liquid directing means in the feedwater portion extends downwardly from all of the bed open discharge sides. a

7. Flash evaporator construction as defined in claim 5 in which the bed means has open discharge sides substantially completely around said bed means and opening generally horizontally into the discharge liquid directing means of the feedwater portion in substantially all horizontal directions from said bed means spaced above the feedwater discharge means; in which cover means is mounted on the feedwater box extending substantially horizontally over the entire bed means completely horizontally between said bed open discharge sides thereby forcing total horizontal discharge of liquid and vapor from the bed means; in which the bed means is an annular bed of aggregate-like material forming an opening within said bed beneath the cover means and spaced horizontally from all of the bed open discharge sides, in which the inlet liquid directing means is operably connected to the bed through the bed central opening for receiving liquid from the feedwater inlet means and directing said liquid to and horizontally in all directions through the bed means and horizontally in all directions from said bed open discharge sides; and in which the discharge liquid directing means in the feedwater portion extends downwardly from all of the bed open discharge sides.

8. Flash evaporator construction as defined in claim 5 in which the bed means has open discharge sides substantially completely around said bed means and opening generally horizontally into the discharge liquid directing means of the feedwater portion in substantially all horizontal directions from said bed means spaced above the feedwater discharge means; in which cover means is mounted on the feedwater box extending substantially horizontally over the entire bed means completely horizontally between said bed open discharge sides thereby forcing total horizontal discharge of liquid and vapor from the bed means; in which the the bed means is a bed of aggregate-like material completely covering an upper part of the feedwater box beneath the cover means; in which the inlet liquid directing means is operably connected to the bed from beneath said bed and spaced horizontally from all of said bed open discharge sides for receiving liquid from the feedwater inlet means and directing said liquid vertically upwardly into and hori- 15 V zontally in all directions through the bed and horizontally in all directions from said bed open discharge sides; and in which the discharge liquid directing means in the feed- Water portion extends downwardly from all of the bed discharge sides.

References Cited by the Examiner UNITED STATES PATENTS 1,962,153 6/34 Peterkin 202-200 X 16 2,759,882 8/56 Worthen et al. 202-53 3,003,931 10/61 Worthen et a1 202-197 X FOREIGN PATENTS 486,229 6/38 Great Britain. 831,478 3/ 60 Great Britain. 1,064,434 8/59 Germ-any.

NORMAN YUDKOF F, Primary Examiner. ALPHONSO D. SULLIVAN, Examiner.'

Claims

1. FLASH EVAPORATOR CHAMBER CONSTRUCTION FOR DISTILLING SEA WATER AND THE LIKE INCLUDING A FEEDWATER PORTION AND A CONDENSING PORTION, FEEDWATER INLET MEANS FOR INTRODUCING LIQUID TO BE DISTILLED INTO THE FEEDWATER PORTIN AND FEEDWAER DISCHARGE MEANS FOR DISCHARGNING SAID LIQUID FROM THE FEEDWATER PORTION, BED MEANS OF AGGREGATE-LIKE MATERIAL SUPPORTED IN THE FEEDWATER PORTION SPACED ABOVE THE FEEDWATER DISCHARGE MEANS AND HAVING AT LEAST ONE OPEN DISCHARGE SIDE SPACED ABOVE THE FEEDWATER DISCHARGE MEANS AND OPENING GENERALLY HORIZONTALLY INTO DISCHARGE LIQUID DIRECTING MEANS IN THE FEEDWATER PORTION, SAID BED OPEN DISCHARGE SIDE EXTENDING DOWNWARDLY TO SUBSTANTIALLY THE LOWEST LEVEL OF SAID BED MEANS WHEREBY IT IS IMPOSSIBLE TO MAINTAIN A STATIC LIQUID LEVEL IN SAID BED MEANS, INLET LIQUID DIRECTING MEAMS FORMED IN THE FEEDWATER PORTION OPERABLY CONNECTED TO THE FEEDWATER INLET MEANS AND OPERABLY CONNECTED TO THE BED MEANS SPACE HORIZONTALLY FROM SAID BED OPEN DISCHARGE SIDE FOR RECEIVING LIQUID FROM THE FEEDWATER INLET MEANS AND DIRCTING SAID LIQUID TO AND HORIZONTALLY THROUGH THE BED MEANS AND HORIZONTALLY FROM SAID BED OPEN DISCHARGE SIDE WHEREBY AT LEAST PART OF THE VAPORS RELEASED FROM THE LIQUID WITHIN THE FEEDWATER PORTION WILL BE RELEASED WITHIN THE BED MEANS AND WILL PASS THROUGH AND OUT OF THE BED MEANS ABOVE SAID LIQUID, THE DISCHARGE LIQUID DIRECTING MEANS FORMED IN THE FEEDWATER PORTION EXTENDING DOWNWARDLY FROM THE BED OPEN DISCHARGE SIDE AND OPERABLY CONNECTED TO THE FEEDWATER DISCHARGE MEANS FOR DIRECTING LIQUID FROM SAID BED OPEN DISCHARGE SIDE ABOVE ANY STATIC LIQUID LEVEL IN THE DISCHARGE LIQUID DIRECTING MEANS OF THE FEEDWATE PORTION, AND DIRECTING SAID LIQUID DOWNWARDLY TO SAID FEEDWATER DISCHARGE MEANS, MEANS IN THE CONDENSING PORTION FOR CONDENSING VAPORS RELEASED FROM THE LIQUID IN THE BED MEANS AND OUTWARDLY OF THE BED OPEN DISCHARGE SIDE, AND MEANS IN THE CONDENSING PORTION FOR COLLECTING THE DISTILLATE RESULTING FROM THE CONDENSED VAPORS.