US2091757A - Heat exchange apparatus - Google Patents

Description

g- 1937- R. M. HANNY 2,091,757

HEAT EXCHANGE APPARATUS Filed May 16, 1935 0 GOOOOQQQGOGOO G mssssss INVENTOR l RUPEETM.HANNY ATTORNEY Patented Aug. 31,- 1937 UNITED STATES PATENT OFFICE HEAT EXCHANGE APPARATUS Pennsylvania Application May 16, 1935, Serial No. 21,823

10 Claims.

My invention relates to heat exchange apparatus, more particularly to heat exchange apparatus in which one fluid is at least partially vaporized, and it has for an object to provide improved apparatus.

A further object is to improve the heat transfer rate of such apparatus.

The present invention constitutes a modification of the invention claimed in the patent of John P. Rathbun, Patent No. 2,084,743, issued June 22, 1937. f

The heat exchanger of the present invention comprises a shell or other vessel in'which there are disposed heating elements, such as tubes containing heating fluid. Bafiies are arranged to provide a plurality of passages through which the liquid flows upwardly in contact with the heating elements to be heated thereby, Other passages are provided for conveying all the liquid rising to the upper end of one hea'ting passage, out of contact with heating elements, to the lower end of the next heating passage. With this arrangement, the liquid flows through the several heating passages in series without recirculation in the individual passages. The vapor formed in each heating passage is removed through the upper portion of the shell. The natural convection currents are thereby utilized to provide maximum flow and heat transfer.

The above and other objects are efiected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a longitudinal vertical section through a heat exchanger embodying the present invention;

Figs. 2, 3 and 4 are sectional views taken on the lines IIII, IIIIII and IVIV of Fig. 1;

Fig. 5 is a broken perspective view showing the 'baflle arrangement; and

Figure 6 is a longitudinal ing a modification.

Referring to the drawing in detail, I show a vertical section showheat exchanger comprising a cylindrical shell I0 which may have an integral closure at one end, as shown at II. vided at the other end of the shell. The shell I0 contains tubes I3 and I4 for circulating heating fluid, the tubes being arranged in a group or nest in the lower portion of the shell, that is, somewhat below the top of the shell as shown on the drawing. The tubes are preferably formed into a removable tube bundle, being connected at one end to a stationary tube sheet I5, whose edges are A removable head I2 is proshown in Figs. 3 and 4. The curved plates 32 secured between flanges I6 and Il, securing the head I2 to the shell I8, and secured at the other end to a floating tube sheet I8. The floating tube sheet I8 carries a floatinghead or cover I9,

, that any suitable heating fluid may be used, for

example, steam may be used, as contemplated by the illustrated embodiment, in which case the tubes I3 may be greater in number than the tubes I4. The steam gives up its latent heat in the tubes I3 and the tubes I 4 serve primarily for returning the condensate to the header I2.

The shell III is formed with a liquid inlet 26, in this case disposed in the lower portion of the shell at the end adjacent the head I2. It is formed with a vapor outlet 21 in the top thereof, and with a liquid outlet 28 in the bottom at the end opposite the inlet 26. A second liquid outlet 280. may be provided, if desired.

The lower portion of the-shell containing the tube nest is divided into a plurality of compartments 29 by partitions 30. The partitions also serve as tube support plates, having openings through which'the tubes are extended. Each partition is somewhat more than semicircular in shape, the upper edge .being disposed a short distance above the top of the tube nest. Each partition 30 has a rectangular opening 3| adjacent the bottom thereof, as shown on the drawing. The tube nest is spaced from the cylindrical wall of the shell, as may be seen in Figs. 3 and 4, and in each of the compartments 29 other than the first, I provide a baflle structure extending about the sides and bottom of the tube nest,

thereby providing downwardly-extending passages 35 onopposite sides of the tube nest. This baflle structure comprises curved plates 32 on opposite sides of the tube nest, the upper edges being at the level of the top of the tube nest and the lower edges being horizontally spaced, as

have extensions 33 adjacent the lower edges which are bent to extend downwardly. The lower edges of these extensions are inclined, as may be seen in Fig. l, and a plate 34 is secured to said inclined edges, as by welding. The extensions 33 for conveying liquid from the opening 3| of the and the plate 34 together form a passage or flume partition on the upstream side (on the left in Fig. 1) to the lower portion of the tube space. The battle structure in each compartment may be secured in any suitable manner, for example, it may be removably secured to the partitions 3!! by being bolted as shown at 36. The baflle structure in the first compartment 29 is modified to provide communication between the tube space and the liquid inlet 26. It comprises a single baflie 31 extending about the bottom and sides and having a conduit portion 38 extending through the passage 35 to the inlet 26.

The Shell is preferably formed with a transversely-extending weir 39 adjacent the floating head l9, thereby insuring that the tubes are completely submerged at all times and also providing a storage chamber 4| between the weir and the closed end ll.

Operation be vaporized and separated from the other, is,

admitted to the shell through the inlet 26 and the conduit 38 to the tube space of the first compartment 29. As it flows upwardly therein, it is through the liquid outlet 28.

heated by contact with the tubes, thereby vaporizing a portion of the volatile component. As it reaches the top of the tube nest, the vaporized portion is liberated and passes into the vapor space constituted by the upper portion of the shell above the tube nest. The liquid spills over the upper edges of the curved baflle and passes downwardly through the passages 35 to the bottom thereof. The liquid then passes into the tube space of the next compartment 29 through the opening 3| in the intervening partition 30, passing to the right as seen in Fig. 1. The liquid is conveyed by the 'fiume formed by-the extensions 33 and the plate 34 to the tube nest, in which it again rises and is heated as it rises. This cycle of operation is'repeated in each of the compartments until it reaches the last compartment 29, from which it spills over the top of the tube sheet l8 and the top of the weir 39 into the storage chamber 4|. From the latter, it is drawn off If it is desired to draw ofi some liquid before the volatile component thereof has been entirely vaporized, the liquid outlet 28a may be used for this purpose. The vaporized portion of the fluid is withdrawn from the vapor space in the upper portion of the shell through the vapor outlet 21.

In the present embodiment, the entire flow of liquid rising to the top of the tube space in each compartment is conveyed through the passages 35 and the opening 3! to the next compartment, so that it does not recirculate in any one compartment. The liquid passes through the compartments in series, as will be apparent from the above description. The above arrangement makes use of the natural convection currents which are set up by the heating of the liquid, which currents are added to the gravity flow current from the liquid inlet end to the liquid outlet end of the shell. Furthermore, the static head on the liquid is repeatedly reduced as it reaches the top of the tube nest so that the lighter fractions may be liberated. Also, the improved flow currents provided prevent the accumulation of vapor bubbles on the submerged hot surfaces of the tubes.

Theabove apparatus is of particular utility in manufacturing petroleum products, in which the liquid admitted to the inlet 26 contains constituents of varying boiling points. The constituents of lower boiling points, known as the lighter fractions are vaporized first, and then constituents of higher boiling-points are successively vaporized as the liquid flows from the inlet end of the shell to the outlet end. In this field, the apparatus is knownas a reboiler.

In some cases, it may be desirable to separately remove the vapors of varying boiling points. In this case, partitions 30a may be extended to the top of the shell, as shown in Fig. 6, in which case there is a separate vapor space in the top of each compartment 29. is provided at the top of each compartment. In other respects, the apparatus shown in Fig. 6 is the same as that shown in Figs. 1 to 5.

While I have shown' my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are set forth in the appended claims.

What I claim is:

1. In heat exchange apparatus, the combination of a shell, means providing heating passages for upward flow of liquid, heating elements in A separate vapor outlet 21a said passages, means for conveying all the liquid rising to the upper portion of one heating passage, out of contact with heating elements, to the lower end of the next heating passage, the liquid flowing through said one heating passage only once before it is conveyed to the next heating passage by said last-mentioned means, and means for removing vapor from the upper end of each heating passage.

2. In heat exchange apparatus, the combination of a shell having a liquid inlet and having a vapor outlet in the upper portion thereof, means providing a plurality of compartments in the lower portion of said shell, heating elements in said compartments, means in one compartment for conveying the entire liquid stream upwardly only once in contact with the heating elements in said compartment and then downwardly substantially out of contact with heating elements to the lower portion of the next compartment, the upper portion of said shell providing a vapor space affording communication between said one compartment and said vapor outlet.

3. In heat exchange apparatus, the combination of a shell;transverse partitions in said shell dividing the lower portion thereof into a plurality of compartments, the upper portion of the tion of a shell, transverse partitions in the lower portion of the shell dividing the same into a plurality of compartments, a group of tubes in the shell extending throug'h the several compartments, and means for conveying all the liquid rising to the upper portion of one compartment out of contact with the tubes to the lower portion of the next compartment without recirculating the same through said one compartment, the upper portion of the interior of the shell constituting a vapor space communicating with the several compartments at ,the top thereof.

' 5. In heat exhange apparatus, the combination of a shell, a group of tubes therein, bailles disposed transversely of the tubes and providing a plurality of compartments, other baflles in the compartments providing first vertical passages through which the tubes extend and second vertical passages substantially without tubes, the vertical passages in each compartment being in communication at the upper ends whereby liquid 7 l5 flows upwardly in the first passage only once and then downwardly in the second passage, and means for conveying liquid from the lower end oi the second passage of each of a plurality of successive compartments to the lower end of the first passage of the next] compartment, said means being sealed oil from the first passage 01' the preceding compartment.

6. In heat exchange apparatus, the combination of a longitudinal shell, a group oi tubes 26 disposed longitudinally in the lower portion of said shell in spaced relation to the longitudinal wall thereof, a plurality of partitions extending transversely of the tubes for dividing the lower portion of the shell into a plurality of compart- 30 ments, baflle means in each compartment disposed partly around the tube bundle to provide a passage between said wall and tubes out of contact with the tubes, the upper edge of said baiile means being disposed below the upper edge 85 oi the partitions to permit liquid to spill thereover, and means for conveying liquid from the lower end of one passage to the lower portion of the tube space of the next compartment, all of the liquid rising to the top of the tube space of one compartment being conveyed, the first time that it rises to the top, through the passage and last-mentioned means to the next compartment.

7. In heat exchange apparatus, the combination 01' a shell, a group of tubes in the lower portion of the shell, partitions extending transversely of the tubes and providing a plurality of compartments in the lower portion of the shell, each partition having an opening adjacent the bottom thereof, baiile means disposed about the sides and bottom oi the group of tubes in each compartment to divide the compartment into a tube space and passages substantially devoid'oi tubes, the upper edges of said bailie means being dis-\ 5 posed to cause liquid rising through the tube space to spill over into said passages, the lower portion of the bame means of one compartment being formed to provide a fiume for conveying liquid from the previous compartment through 80 the opening in the intervening partition to the lower end or the tube space and to conveythe liquid flowing downwardly in the passages through the opening in the partition on the opposite side of the compartment into the lower 65 portion of the tube space in the next compart men 8. In a heat exchanger, the combination of a shell, a'bundle of heating tubes disposed horizontally therein, said bundle of tubes being arranged to provide space substantially devoid of tubes extending from the top to the bottom of the tube bundle, a baille extending longitudinally along the side of the tube bundle and dividing the tube containing space from the space devoid of tubes, baflies extending transversely of the tubes and dividing the tube containing space into a pluraliity of heating passages, and baiiie means in the space devoid of tubes providing a passage arranged to convey liquid from the top or one heating passage to the bottom of the next heating passage, said last-mentioned passage constituting the only outlet for liquid rising to the top of said one heating passage so that the liquid flows but once therethrough.

9. In a heat exchanger, the combination of an elongated shell having a liquid inlet and a liquid outlet, a bundle of heating tubes disposed horizontally and longitudinally therein, said bundle of tubes being arranged to provide a space sub, stantially devoid of tubes extending from the top .to the bottom of the tube bundle, a baflle extending longitudinally along the side of the tube bundle and dividing the tube containing space from the space devoid of tubes, baiiies extending transversely of the tubes and dividing the tube containing space into a plurality of heating passages through which the liquid flows successively from said liquid inlet to saidliquid outlet, baiiles in the space devoid of tubes dividing the sameinto a plurality of passages each arranged to convey liquid from the top of one heating passage to the bottom of the next heating passage, each of the last-mentioned passages constituting the only outlet for liquid rising to the top or the said one heating passage so that liquid flows but once through each heating passage, and means for removing the vapor from the liquid at the upper end of each heating space.

10. In a heat exchanger, the combination of a shell, a bundle of heating tubes disposed horizontally therein, said bundle of tubes being arranged to provide space within the shell devoid oi tubes extending from the top to the bottom of the tube bundle, partitions extending transversely of the tubes and dividing the tube-containing space into a plurality of heating passages, the top of the tube bundle and the upper edges of said transverse partitions being spaced from the top of the shell to provide a vapor space in the upper portion of the shell for receiving vapor from the several heating passages, and partition means providing passages in said space devoid of tubes for conveying liquid from the top of one heating passage to the bottom of the next heating passage, at least a portion of the upper edges of said partition means being disposed below the upper edges of said transverse partitions, said partition means preventing recirculation of liquid through a heating passage through which it has already flowed, and said shell having a. liquid inlet communicating with the lower end of the first heating passage and a vapor outlet communicating with said vapor space.

- RUPERT M. HANNY.

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