US788804A - Process of evaporating liquids. - Google Patents

Description

No. 788,804. v PATENTED MAY 2, 1905. J. H. WALLACE J. B. SPEED. PROCESS OF EVAPORATING LIQUIDS.

APPLIGATION FILED QOT. 25, 1904.

3 SHEETS-SHEET 1.

No. 788,804. -PATENTED MAY 2, 1906. J, HLWALLACE & J. B. SPEED. PROCESS OF EVAPORATING LIQUIDS.

APPLICATION FILED O0T.25,1904.

3 SHEETS-SHEET 2.

PATENTED MAY 2, 1905.

s SHEETS-BHBET a.

J. H. WALLACE & J. B. $PEED. PROCESS OF EVAPOEATING LIQUIDS.

APPLIUATION YILED OCT. 25, 1904.

' NITED STATES Patented May 2,1905.

PATENT OFFICE...

JOHN HERBERT l/VALLAOE, OF SAN FRANCISCO, AND JAMES BUCKNER SPEED, OF BERKELEY, CALIFORNIA.

PROCESS OF EVAPORATING LIQUIDS.

SPECIFICATION forming part of Letters Patent No. 788,804, dated May 2, 1905.

Application filed October 25,1904. Serial No. 229,891.

To all, [Ix/tum, 17/; may concern.-

Be it known that we, JOHN HERBERT AVAL- LACE, residing in the city and county of San Francisco, and JAMES BUGKNER See an, residing at Berkeley, Alameda county, State of California, citizens of the United States, have invented certain new and useful Improvements in Evaporating Liquids; and we do hereby declare the following to be a full, clear, and exact description of the same.

Our invention relates to the art of evaporation and may be well applied as a process of distillation.

The object of our invention is to reduce the losses of heat in multiple-effect evaporation or distillation.

The process consists in a series of evaporations and condensations taking place in such a way that an initial evaporation is eiiected under conditions of high temperature and pressure followed by a first condensation which is under substantially the same pressure as the initial evaporation, said condensation being caused by reason of a second evaporation at a lower pressure and temperature in azone which surrounds the zone of said condensation, said second evaporation abstracting the heat from the zone of first condensation sufficiently to cause said condensation, then causing the vapor of the second evaporation to be condensed in a second surrounding zone of condensation at substantially the same pressure as said second evaporation by a third zone of evaporation which surrounds the said second zone of condensation. and so on throughout a further series of evaporations and condensations, each of which surrounds all the preceding, thereby, briefly stated, causing the several steps to take place in a series of effects under progressivelydirninished heats and pressures, said effects being successively inclosed the one within the other, the hottest or highest pressure effect being the innermost.

Referring to the accompanying drawings, we have shown three forms of an elemental apparatus in which our process be carried out, though it is to be understood that we do not confine ourselves to such apparatus, for in practice the construction will be elaborated to suit the necessities of the case. These forms will, however, be sutticient to fully illustrate the essential i ties of the process.

Figure l is a longitudinal section of one form of illustrative apparatus. Fig. 2 is a similar section of a second form. Fig. 3 is a similar section of a third form.

In Fig. l, A is the initial reservoir or vessel for the liquid to be evaporated, said vessel having applied to it the necessary heat, represented by the flame B, and having also a controllable supply-pipe C to admitthe liquid under pressure and a pressure-gage D. From the vessel A extends a tube E,closed at its outer end and having a controllable outlet (4. Eneircling tube E is a second tube F, closed at each end, as shown. Into the lower part of one end of this tube F is let a controllable pipe 7, which leads from the source of supply of the liq uid to be evaporated. From the u ppcr part of the same end of the tube F leads an exitpipe f into the upper part of the closed end of a third tube G, which encircles tube F. This tube Gr has its ends closed, and from the lower part of its end opposite to that at which the pipe f enters issues a controllable exitpipe 9. Encircling the tube G is a fourth tube H, closed at each end. Into the lower part of one end of tube H is let a controllable supply-pipe h from the liquid under pressure, and from the upper part of said end of tube H issues an exit-pipe it. This series of concentric tubes thus connected may be extended as far as desired; but the number here shown, in which two effects may be carried out, is sufiicient to illustrate a greater numberof effects. To avoid confusion, the process carried out in this apparatus will be described in full before referring to the succeeding forms of Figs. 2 and 3.

Assume the liquid to be evaporated or distilled is water and that the supply-pipes (1,

f, and it lead from the city water-mains, carrythus the hottest of the series of concentric tubes. Tater from the main being supplied through pipe f to the second tube F condenses the vapor in tube E, distilled water being drawn off through pipe 6, while said vapor yields up its heat to the water in said tube F, producing a second evaporation under lower temperature and pressure, the vapor therefrom passing off through pipe f into the third tube G under the same pressure as that of said second evaporation. ater from the main being supplied through pipe it to the fourth tube H condenses said vapor in tube G, distilled water being drawn off through pipe g, while said vapor yields up its heat to the water in tube H, producing a third evaporation under still lower temperature and pressure, the vapor from which passes off through pipe it. It will now be seen that the radiation of heat from the hottest part of the apparatus is always directed toward other su rfaces which it is desirable to heat, and thereby the radiation losses are diminished.

By concentrically inclosing or nesting the several effects in series substantially all the bounding-walls of those on the interior become active as heat-transmitting surfaces. As the hottest efi ect is best placed inside and the coolest outside, the arrangement is to a large extent selfinsulated against the loss of heat, little radiating-surface being exposed except the comparativelylow temperatured exterior effect.

In the form of apparatus shown in Fig. 2 the same letters of reference are employed to designate similar parts as far as practicable. Thus we have the initial vessel A, the source of heat B, the water-supply C, the pressuregage D, and the concentric or nested tubes E, F, G, and H. The connections of these effects differ somewhat from those shown in Fig. 1. The chief differencelies in the water-supply pipes. In this form the second tube F is supplied by a controllable pipe f from the water in the initial vessel, while the fourth tube H is supplied by a controllable pipe [2 from the water in the second tube. As in Fig. 1, the second tube F of Fig. 2 has a vapor-outlet f into the third tube (Jr, and the fourth tube H has a vaporoutlet it; but in Fig. 2 the distilled water from the inner tube E passes through a controllable pipe 6 into the third tube G where it joins the distilled water in said tube and is .drawn off through outlet g. The concentrate is drawn off from the outermost effect or tube H by a pipe [2/5. In this form of apparatus the initially-heated Water is progressed through the apparatus.

In the form of apparatus shown in Fig. 3 the concentric series of effects begins with a water-containing tube into which a heater is introduced, as would be the case where a boiler is used as the initial heater. In this form the central heater J is shown for con- Venience in the form of a retort. Around the neck of the retort is fitted the tube F, which is encircled by a tube G, itself surrounded by a tube H, which is encircled by a tube K, around which is an outer tube L. The water-supply from the main is through pipe C and controllable branches 0, both direct and intercommunicating to each of the tubes F, H, and L, while the vapor connections are by pipes 0 from F to G, from H to K, and from L to any succeeding effect. The distilled-water connections are the pipes a and g, as in Fig. 2, and the concentrateoutlet is pipe if, as before.

In our process, as the extreme economy in heat results in the delivery of all vaporized liquids in a recondensed comparatively cool form, said process is useful as a still as well as an evaporator.

Although we have shown and described the several etfects as being concentric, we are not to be understood as confining ourselves strictly to a concentric arrangement, for the effects may be only substantially concentric or they may be somewhat eccentric, the idea being that whatever their shape may be, whether cylindric or semicylindric or polygonal, they shall be nested inside one another, surrounding or enveloping each other in series.

Having thus described our invention, what we claim as new, and desire to secure by Let ters Patent, is-

In the art of evaporating liquids in multiple effect, the process which consists in initially evaporating the liquid under conditions of highest temperature and pressure; then causing the resulting vapor to be condensed at the same pressure, by evaporating the liquid under conditions of less temperature and pressure, in a zone surrounding the zone of first condensation, said second evaporation taking place by reason of the heat from the first zone of condensation; then causing the resulting vapor from the said second evaporation to be condensed at the same pressure as said second evaporation, in a zone surrounding the zone of second evaporation, by evaporating the liquid under conditions of still less temperature andpressure, in a zone surrounding the zone of second condensation, said third evaporation taking place by reason of the heat from the second zone of condensation; and so on, alternating evaporations and condensations in surrounding zones, at diminishing pressures and temperatures.

In witness whereof we have hereunto set our hands.

JOHN HERBERT WVALLACE. JAMES BUCKNER SPEED. Vitnesses:

M. H. SHIELDs, E. L. ALLEN.

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