US1795601A - Apparatus for concentrating solutions - Google Patents

Description

March 10, 1931. v j HAMILL AL 1,795,601

APPARATUS FOR CONCENTRATING SOLUTIONS Filed Dec. 4, 1925 6 Sheets-Sheet 1 March 10, 1931. J. HAMILL ET AL APPARATUS FOR CONCENTRATING SOLUTIONS Filed Dec. 4 1925 6 Sheets-Sheet 2 oooooo wo wo oodo o oooooo ooooooqo/o/ooo INVENTOR I A, M

A TTORNE Y March 10, 1931. J. HAMlLL ET AL 1,795,601

APPARATUS FOR CONCENTRATING SOLUTIONS Filed Dec. 4 1925 6 Sheets-Sheet 5 A TTORNEY March 10, 1931. J. HAMILL ET AL 1,795,601

APPARATUS FOR CONCENTRATING SOLUTIONS Filed Dec. 4, 1925 6 Sheets-Sheet 4 E BY l L%24 A TTORNE Y March 10, 1931. .1. HAMILL ET AL APPARATUS FOR CONCENTRATING SOLUTIONS 1925 6 Sheets-Sheet 5 Filed Dec.

o o o o o 080 0 0 o o o o INVENT0R- B 3% ATTORNEY March 10,-1931.

J. HAMILL ET AL APPARATUS FOR CYONCENTRATING SOLUTIONS 4 1935 6 Sheets-Sheet 6 Filed Dec.

o o o o o o o o o omowowo o o o o o o o o 0 Q0 0 0 0 0 0 0 0 0 0 o o o o o o o o o o o o o 0 0 o o o o o o o o o o o o o o w o oo owo o o O O O o o o 0 0 0 0 0 0 0 0 0 0 0 o o o o oo o o o o o oo o o o o INVENTOR Y ZJ W ATTORNEY o o o o o 0 00 o o o 0 0 0 O O 0 0 O O o o o o o o oo o o o o o o .0 0 u/ o owo o oooo Patented Mar. 10, 1931 UNITED STATES PATENT OFFICE JAMES HAMILL, OF EAST ORANGE, NEW JERSEY, JOHN FREDRICK TADDIKEN, OF FOREST HILLS, YORK, AND GEORGE WILLIAM CONNON, OF MONTCLAIR, NEW

JERSEY APPARATUS FOR CON GEN TRATIN G SOLUTIONS Application filed December 4, 1925. Serial No. 73,092.

This invention relates to apparatus for concentrating solutions by the evaporation or distillation of a solvent, and particularly refers to the evaporation of solutions such as beet and cane sugar juices.

Our invention relates more particularly to apparatus for evaporating such liquids whether used With single or multiple effects, or whether used to evaporate under pressure or under vacuum; and also to evaporator-s and vacuum pans known to those skilled in the art as the standard vertical tube type.

Our invention further relates to apparatus for causing the steam, or other heating fluid, to flow, with substantially uniform velocity, around the vertical heating tubes to wipe off the film of air .and incondensable gases from said tubes, so that the rate of evaporation of the liquor within the vertical tubes is increased and the circulation of said liquors improved.

Our invention further relates to causing the steam, or other heating fluid, to move in a definite and predetermined path through the bank of vertical heating tubes thereby lessening the resistance to the passage of the steam and the formation of eddy currents and increasing the rate of evaporation and the circulation of the liquor in the heating tubes.

Our invention further relates to causing the steam, or other heating fluid to flow not only along definite and predetermined paths through the bank of vertical heating tubes,

but paths which constantly narrow and de-.

crease in area, thereby maintaining the velocity of the steam, or other heated fluid, in its passage around said vertical heating tubes.

Our invention further relates to certain combinations and sub-combinations as will be more fully hereinafter described and pointed out in the claims.

Other objects and advantages of the inven tion will be set forth in part hereinafter and in part will be obvious therefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and, combinations pointed out in the appended claims.

The accompanying drawings referred to herein and constituting a part hereof, illustrate one embodiment of the invention and together with the description serve to explain the principles of the invention.

Of the drawings Fig. l is a front elevation of a multiple elfect showing a plurality of cells;

Fig. 2 is a horizontal section substantially 0n the line 2-2 of Fig. 4, aportion of the lower tube sheet being broken away for purposes of illustration;

Fig. 3 is a vertical section, substantially on the staggered section line 3-3 of Fig. 2;

Fig. 4 is a vertical section through the calandria on the line 44 of Fig. 2;

Fig. 5 is a horizontal section through a modified form of calandria, showing a different arrangement of steam inlet and a different arrangement of vertical heating tubes;

Fig. 6 is a vertical section through a vacuum pan equipped with our invention;

Fig. 7 is a horizontal section through a vacuum pan shown in Fig. 6, taken on the line 7-7 of Fig. 6.

It is, of course, to be understood that our invention may be used either with evaporators of the standard vertical tube type, whether such evaporators are single or multiple effect, and with vacuum pans to further evaporate and concentrate the beet and cane sugar juices. Such a vacuum pan is shown in Figs. 6 and 7.

In the drawings, and more particularly Fig. 1, we have shown two standard vertical tube type evaporators A and B connected in multiple effect by the pipe C. The first cell A is supplied by steam, or other heating fluid, through the steam inlet 1. This steam enters into the steam chamber 2 which is provided with openings 3, 3, a baffle plate 4-, and inclined directional walls 5, 5 (see Fig. 4:.)

This steam chamber 2 directs the incoming steam into that portion of the cell A lying between the upper tube sheet 6 and the lower tube sheet 7 in which tube sheets are mounted a plurality of vertical heating tubes 8, 8. This portion of the standard vertical tube type evaporator is known as a calandria 9. These vertical heating tubes 8, 8 are secured in the upper and lower tube sheets 6 and 7 in any suitable manner, such as by rolling 01' otherwise. At approximately the center of the tube sheets 6 and 7 is mounted a downtake 10.

The solution to be evaporated, such for example as beet or cane sugar juices, is fed into the cell A through the liquor inlets 11 and 12, filling the lower portion 13 of the cell A and passing up through the vertical heating tubes 8, 8 and thence over the upper tube sheet 6 and down the downtake 10, the latter acting as a weir. The juices continue to circulate in this manner within this effect or cell A until they have reached the desired concentration, when they are withdrawn through the liquor outlet 14. When cell A is coupled up to form a multiple effect, the partially evaporated juices pass from cell A to cell B through the pipe and pipes 36, 36, to be hereinafter described.

The vapor from the boiling liquor in the first effect or cell A passes through the pipe C either directly to a condenser, or, when the cell is coupled up to form a multiple efiect', it

passes into the calandria of the second cell, as for example B in Fig. 1, where it is utilized to further evaporate and concentrate the cane or beet sugar juices in that cell.

It is found in practice that the liquor to be concentrated does not circulate uniformly in the different vertical heating tubes 8, 8 and that the steam, or other heating fluid, is not used economically or to the best advantage in the calandria. There are several reasons for this and among others: The vertical heating tubes become coated with a film of air, or other incondensable gases, which more or less insulate the vertical heating tubes from the steam or other heated fluid, so that the evaporation and the rate of flow of the liquor through the vertical tubes is not uniform, nor is it the same in tubes located at different portions of the calandria, thereby reducing the efficiency of the effect. Again the steam or other heating fluid in the standard form of calandria follows no definite and predetermined path. This permits of the formation of dead spaces and eddy currents in the calandria. Again the entire length of the diflerent vertical tubes is not equally heated. This also interferes with the condensing of the steam on the vertical heating tubes, which will not be uniform.

By our invention we insure that the film of air, and other incondensable gases, on the vertical heating tubes 8, 8, which acts as an insulating medium, shall be removed by the steam or other heating fluid. We do this preferably by maintaining a substantially uniform velocity of the steam through the calandria by making the steam follow defi-,

nite and predetermined paths the area of said paths constantly narrowing or decreasing so that the velocity of the steam throughout the calandria will be suflicient to sweep and remove the a1r film from the vertical tubes 8, 8,

thereby permitting increased heat transmission to the liquor and better circulation. We also collect or trap this air, and condensable gases, within sections or pockets of the calandria, from which pockets the air and gases are Withdrawn; after being cooled as much as necessary to give the desired increase in partial air pressure.

We have shown the Vertical heating tubes arranged in different sets or banks, the spacing of the vertical tubes in each bank or set being equal distance from each other, but different from those in another bank or set, the section or bank having wider spacing being adjacent to the steam chamber 2 so as to present the minimum resistance to the flow of the steam and the other sections or banks being correspondingly arranged to form narrowing steam paths;

lVe have shown in Fig. 2 for example, a calandria divided into different sectors X, Y, Z, it being understood that these sectors are duplicated on that portion of the calandria which is broken away in Fig. 2 (see Fig. 7). The velocity of vapor into the calandria of an evaporator is induced by, and is directly proportional to, the weight of steam condensed in the calandria, the steam pressure being assumed constant.

The steam entering the steam chamber 2 will be directed by the inclined surfaces 5, 5 and the openings 3, 3 towards each end of the vertical heating tubes 8, 8. The steam will first follow the different paths 20, 20 between the different vertical heating tubes in the bank or sectors X, X (one being illustrated in Fig. 2) where the Vertical heating tubes 8, 8 are spaced the greatest distance from each other to offer less resistance to the passage of the steam and form less eddy currents. The steam will then pass between the vertical tubes 8, 8 in the sectors Y, Y, (only one being illustrated in Fig. 2) which will also form a continuation of the steam paths 20, 20. But the area of the steam passages 20, 20 in sectors Y, Y, will be reduced and consequently the velocity will be maintained. This also applies to the continuation of the steam paths 20, 20 in sectors Z, Z where the tubes are mounted still closer together, which will still further reduce the area of the steam passages thereby maintaining the velocity and insuring that the steam will have sufficient Velocity to wipe off all the air film, and other incondensable gases, from the different vertical heating tubes 8, 8, in whatever sector or bank of tubes they may be mounted.

The end of the steam paths, are the pockets 21, 21 (only one being shown in Fig. 2, see Fig. 7) which are formed by the plates 22, 22 (only one being shown in Fig. 2) connecting the upper and lower tube sheets 6 and 7. We preferably also employ guide plates 23, 23 (only one being shown in Fig. 2; see Fig. 7), which serve to extend the pockets or chamber 21, 21 and to trap the air, and incondensable gases, and lead them into the pockets 21, 21. At the very end of the pockets 21, 21 are provided perforated diaphragm plates 24, 24, one to each pocket, which are shown more in detail in Fig. 6. These form inner chambers 25, 25 at the end of the pockets 21, 21 for the collection of the air and incondensable gases, and from these inner chambers such air and incondensable gases are withdrawn by the escape pipes 26, 26. To utilize the heat of the air and incondensable gases we preferably mount several of the vertical heating tubes 8, 8 in the pockets or chamber 21, 21 and also one of them in the inner chambers 25, 25. The circulation of the liquor through these verti-' cal heating tubes serves to absorb some of the heat of the air and incondensable gases, and reduces their volume and temperature prior to being withdrawn through the pipes 26, 26. The perforations in the diaphragm plates 24, 24 enable the air and other incondensible gases, to be drawn uniformly into the inner chambers 25, 25 over the entire vertical height of the path of steam between the upper and lower- tube sheets 6 and 7.

To insure that the steam will take the predetermined paths 20, 20 through the different sets or banks of vertical heating tubes in the sectors X, X, Y, Y and Z, Z (only one of each of the sectors being shown in Fig. 2; see Fig. 7) we preferably employ bafile plates 27, 27'mounted on the downtake 10 and also other baflle plates 28, 28 mounted on the interior circumference of the calandria.

To insure that all of the heating surface is effective, it is necessary to provide eflicient means of removing the condensate as soon as formed. In our invention, we collect the condensate by means of a well or angular ring 29 (Figs. 3 and 4), which ring extends beneath the level of the lower tube sheet 7 permitting the condensate to run off of said lower tube sheet 7 into the ring or well, where it is withdrawn by the condensate drain pipes 30 and 31.

It will be noted that in our calandria the downtake 10 is in the form of an inverted frustum of a cone. This permits us to install the well or annular collecting ring without reducing the number of vertical heating tubes 8, and at the same time without impairing the circulation of the liquor in the downtake 10. Moreover by our construction there is a more or less yielding or resilient connection between the lower end of the downtake 10 and the lower tube sheet 7, which will allow for expansion and contraction of the parts without breakage or leakage.

When cell A is used as one cell of a multiple effect, as shown for example in Fig. 1, the pressure and temperature of the steam in the different calandrias are greater than the pressure and temperature of the vapor from the boiling liquor. For example, in the double eflect shown in Fig. 1, the cell B receives from cell A its steam and vapors through the pipe C which passes into the calandria of cell B. When cellA is so connected in multiple effect, the partially evaporated or concentrated liquor from it passes through the pipes 35 and 36, 36 into the calandria of the next cell, for example B, Fig. 1. The temperature of this liquor from cell A entering cell B, is higher than the boiling point of the liquor in cell B. This heat in the liquor is immediately converted into steam when the pressure of the liquor is lowered. If not controlled in a suitable manner, this flash. of liquor disturbs the circulation of the liquor in the next succeeding cell, as for example B. This reacts on the rate of evaporation in the cell and increases the liability to entrainment and foaming of the liquor. This, of course, will, also be true in any additional cells which may be coupled up to cells A and B.

By our invention we prevent thisdisturbing of the circulation of the liquor and retarding of the rate of evaporation in the cell and liability to entrainment and foaming of the liquor, by distributing the liquor and the flash liberated from the heated liquor over a large number of vertical heating tubes 8, 8. F or example, we feed the heated liquor from the prior effect, as for example, cell A, into a gutter or compartment 38, Fig. 3, over which is mounted perforated plates 39, 39. Preferably, we arrange a plurality of these gutters or compartments 38, 38 and perforated plates 39, 39 in different portions of the calandria by dividing the flow of the heated liquor passing through pipe 35, causing it to flow into a plurality of pipes 36, 36 and thence into a plurality of gutters or compartments 38, 38. It is obvious that in this way we distribute the flash over a large number of vertical tubes 8, 8.

The liquor inlets can be placed in a position best suited to make the evaporation more uniform. When heated liquor from a prior cell of a plurality of efi'ects is fed into the calandria the liquor inlets are remote from the vapor and steam inlet, as shown in cell B. With new or fresh liquor coming into the first cell, as for example, A, where the liquor temperature is lower than the boiling liquor in cell A, we preferably arrange the liquor inlets 11 and 12 on the same side of the cell or calandria as the steam chamber 2. The liquor from the cell B is withdrawn through the liquor outlet 40, to pass into another succeeding cell, or to be treated directly in the vacuum pan 42 shown in Fig. 6. The condensate is withdrawn through the outlet 41.

We have shown a modification of our invention in Fig. 5, as applied to an evaporator for thin juices, where instead of using a steam distributing chamber 2, we employ a double steam inlet 50 and 51, so that the steam will flow as indicated by the arrows 52, 52 in certain predetermined definite paths through the banks of vertical heating tubes 8, 8. It is, of course, to be understood that the diflerent groups or banks of vertical heated tubes 8, 8 are duplicated on that portion of the calandria which is broken away in this figure for clearer illustration. In this form of our invention, instead of arranging the sets of vertical heating tubes in different sectors as X, Y and Z (Figs. 2 and 7), they are formed in different sections M, N. O. P Q, R, which sections, of course, are duplicated on the portions broken away in the figure.

In these sections the vertical heating tubes are arranged with maximum space between them in section M; in section N the vertical heating tubes are a little nearer together and this progressive narrowing of the steam path area continues throughout the sections 0, P, Q and R, the vertical heating tubes in these sections being progressively nearer together so as to reduce the steam area, maintain the velocity of the steam, and insure that it passes in definite paths so as to wipe off any film of air or incondensable gases on the vertical heating tubes, and sweep this air and incondensable gases into the pockets 21, 21 (only one being shown). From the inner chambers 25, 25 of these air pockets the air and incondensable gases are withdrawn by the escape pipes 26, 26, after passing through the perforated diaphragm plates 24, 24, in the manner previously described at length in connection with the other figures.

The vacuum pan 42 (Figs. 6 and 7) is of the same general design as the evaporator that we have just described, except that it is modified to suit the purpose of a vacuum pan, which is employed to concentrate beet and cane sugar juices of greater density than the thin liquors used in the evaporators previously described. The principles applied for the improvement of the heat transmission and for the increase of the output are the same.

In our vacuum pan, shown in Fig. 6, we preferably extend the downtake 43 some little distance below the lower tube sheet 7 so that its end 44 extends into the bottom chamber 45 of the vacuum pan, which will assist the circulation of the liquor in the conical bottom of the pan.

In this form the well or annular ring 46 is of a little different construction from the well or annular ring 29, shown in Fig. 4. It

' braces the lower end of the downtake, and

yet makes a more or less yielding connection between the downtake and the lower tube sheet 7, to compensate for expansion and contraction strains. This well or annular ring 46 is connected with the condensate drain pipe 47 to draw off the condensate.

Having thus described this invention in connection with illustrative embodiments thereof, to the details of which we do not desire to be limited, what is claimed as new and what is desired to secure by Letters Patent is set forth in the appended claims:

1. A calandria for evaporating sugar-containing liquids including in combination a container, a steam inlet, a steam passage of progressively decreasing cross-section from the inlet, and a plurality of vertical tubes for the passage of the liquid to be evaporated, the spacing between said tubes being progressively decreased from the steam inlet to the end of the steam path according to a predetermined ratio.

2. A calandria for evaporating sugar-containing liquids including in combination a container, a steam inlet, a steam passage of progressively decreasing cross-section from the inlet, and a plurality of vertical tubes for the passage of the liquid to be evaporated, the spacing between said tubes being progressively decreased from the steam inlet to the end of the steam path, whereby the flow of steam is maintained throughout its passage.

3. A calandria for evaporating sugar-containing liquids including in combination a container, a steam inlet, a central down-pipe, a plurality of narrowing passage ways for the steam formed by the down pipe and baffie-plate extending inwardly toward the downpipe, and a plurality of vertical tubes for the passage of liquid, said tubes being spaced progressively closer together from the steam inlet to the end of the steam path according to a predetermined ratio.

4. In the calandria of an evaporator of the vertical tube type the combination of an inlet for heated condensible fluid, a plurality of heating tubes spaced progressively closer together along the path of the fluid to provide a steam path of progressively decreasing cross-section, a down-pipe for the liquid approximately in the center, and means on the outer wall of the calandria for collecting and withdrawing the incondensible gases removed from the surface of: the tubes by the passage of the fluid.

5. In the calandria of an evaporator of the vertical tube type the combination of an inlet for heated condensible fluid, a plurality of heating tubes spaced progressively closer together along the path of the fluid to provide a steam path of progressively decreasing cross section, and a down-pipe for the liquid approximately in the center of the calandria.

In testimony whereof, we have signed our names to this specification.

JAMES HAMILL. JOHN FREDRICK TADDIKEN. GEORGE WILLIAM CONNON.

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