US2223311A - Heat exchanger - Google Patents

Description

Patented Nov. 26, 1940 UNITED STATES.

PATENT o1=1=1c1.:

man EXCHANGER.

Delaware Application September 26, 1939, Serial No. 296,560

2 Claims. This invention relates to improvements in heat exchangers of the so-called "shell and tube type,

and more particularly relates to the construction of the baflles for a sub-cooler.

5 It is well known that in shell and tube heat exchangers, it is customary practice to provide in ternal bailling to produce a circuitous flow oi fluids in the tubes as well as in the shell. It is important, however, that the baflles be substan- 10 tially tight against by-passing, and also be readily secured to the unit. Many forms have been used but they have either been of a complicated adjustable type or some compromise had to be tolerated in leakage.

5 In accordance with the present invention, an exchanger for cooling of condensate is provided with a fully confined, non-adjustable balile to produce an internal drain of condensate for subcooling purposes and such bailie is substantially 20 liquid tight, readily removed, and inexpensive in construction.

A still further object and advantage of the invention is to provide a high pressure, heavy duty heat exchanger with a nozzle construction 25 which meets all code requirements for strength,

and which permits the removal of the shell without destroying the nozzle connections.

Further objects and advantages of the invention will appear from the following description 30 of a preferred form of embodiment thereof, taken in connection with the attached drawing, in which Fig. 1 is a partial side elevation of a heat exchanger with parts broken away to show the in- 35 ternal construction;

Fig. 2 is a partial transverse vertical section on a slightly larger scale and taken substantially along the line 22 of Fig. 1. 1

In the preferred form of embodiment of the 40 invention, as shown in Fig. 1, the heat exchanger generally represented as ,I is of a heavy duty type and is provided with a forged channel I! and integral fixed tube sheet ll, from which the tube bundle l extends. The other-ends of the tubes 45 I5 are secured in suitable fashion to a'floating tube sheet (not shown), and all of the construction is embraced within the shell IS.

The channel I: is also preferably provided with a shell extension I! into which nozzles l8 and l9 50 are secured. Code requirements make it necessary to use a spacing at least twice the metal thickness between the nozzles and the nearest welds, which are at the joints with the channel at 2| and at 22 with the flange 20. This neces- 55 sarily controls the'spacing of the flange 20 from the channel II, the flange 20 being the attaching flange .for the flange 23 on the shell l6.

In the normal construction of a cooler, the channel I! receives cooling water through the nozzle 24 and by suitable bailling in the channel, 5 such as is indicated at l2a, the heated water is eventually discharged out nozzle 25. The condensate enters the nozzle l8 and comes in contact with the water-cooled tubes l5 with the subcooled condensate being drawn oil from the nozzle l9.

In accordance with the present invention, a baille 26 is provided to assure an added subcooling of the condensate before it reaches discharge nozzle I9. This baflle is substantially horizontal and extends across the lower part of the heat exchanger from a point adjacent the fixed tube sheet Id of the channel to a point along the length of the tubes sufliciently far to assure an adequate contact of the condensate which falls to the bottom. This battle is preferably welded along the transverse line 21 to the fixed tube sheet and is welded along the longitudinal line 28 to the channel extension section ll. It will be obvious that in this channel extension section I! there can be no possible by-passing of condensate from the nozzle l8 through to the nozzle l9.

To complete the internal drain section, a par tially cylindrical bafile 30 surrounding the lower portion of the tubes is integrally secured to the 30 horizontal baflle member 26 as by a plurality of securing devices 3| along the edges thereof. Throughout the length of this lower pan or baille, there is also no possibility of the condensate by-passing, and the condensate intimately contacts with all of the lower portion of the tube bank. If desired, a plurality of vertical ballles 33 may also be used, certain ones projecting downward from the baffle member 26, and certain others projecting upward from the pan 3!! toward the horizontal plate 26. By suitably staggering these baiiies, the condensate must pass across the lower portion of the tube bank in a circuitous path with the most intimate contact with the tubes.

The lower part of the baifle forming the internal drain cooler is preferably provided with an outwardly flanged edge 34, which is conveniently countersunk into and secured as by screws 35 to the flange 20. It will be apparent that by removing the bolts 31, the shell it may be removed from the heat exchanger and thereafter the screws 35 and H can be withdrawn to completely remove the lower portion of the baflie.

The entire surface of the internal drain cooler is surrounded by what amounts to a separate shell contained within the heater. That part of the drain cooler that is not removable is within the short non-removable section of the shell as formed by the stationary tube sheet forging. The flat top of this compartment, which would be similar to a horizontal bailie, is fully welded to the stationary tube sheet, and the short section of the shell that is permanently attached to this forging. The remaining portion of the internal I drain cooler shell is independent of, but may be integrally secured to the curved bottom part, and as'this part fits into a recess in the flange 20, a gasket seal is provided which prevents may bypassing or leakage.

The condensate may be kept at a desired level by the last baffle 3%, which acts as a weir. It is, of course, apparent that if the nozzle H9 were placed on the side rather than on the bottom, it might be placed at a suitable elevation for controlling the condensate level. i

It is of considerable advantage that the nozzles can be permanently welded in place and that the joints need not be broken for replacement of tubes and disassembly of the shell when necessary. The auxiliary section H not only provides for this, but also assures a complete contact of the condensate entering at it with the entire tube area, which would not otherwise be possible.

While a' preferred form of embodiment of the invention has been described, it will be apparent that modifications may be made thereto without departing from the spirit and scope of the invention, and it is, therefore, desired that a broad interpretation be given within the spirit and scope of the description herein and of the claims appended hereinafter.

We claim:

1. In a heat exchanger of the class described having a channel, a shell, means to secure the shell to the channel, and a plurality of tubes extending into the shell, the combination of means to form an internal drain cooler surrounding a portion of said tubes, said means including a fixed plate and a detachable plate each extending along the length of the tubes, means to detachably secure said plates together along their longitudinal edges, said fixed plate being integrally secured at one end to the channel, means to detachably secure the other plate to the channel, said means including a lip on the edge of said plate and means to seal said liphetween the shell and channel, said drain cooler forming a liquid path between the channel on one end and a point within the shell spaced therefrom, said drain cooler being removable after the shell is removed.

2. A heat exchanger of the class described ineluding-a channel having an integral tube sheet, nozzles for said channel, an integral channel extension portion on the opposite side of the tube sheet from said nozzles, a nozzle on said extension portion, a shell detachably secured to said extension portion, a longitudinally extending baffle integrally secured to the tube sheet and to the side walls of the extension portion, a partially cylindrical baiile below said first mentioned bailie, means to join said baflles along their longitudinal edges to form leak-proof joints, said second bafiie having a portion engaging between the shell and the extension portion to form a leakproof joint therewith, means to secure said engaging portion to the channel extension portion whereby said baflle maybe removed after said shell is detached, said baflle members constituting an internal drain cooler in communication with the nozzle in the extension portion on one end and being open to the interior of the shell on the other end.

FREDERICK D. BERKELEY. JOHN A. GIBB.

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