US2523174A

US2523174A - Heat exchanger

Info

Publication number: US2523174A
Application number: US655824A
Authority: US
Inventors: George A Worn
Original assignee: Lummus Co
Current assignee: CB&I Technology Inc
Priority date: 1946-03-20
Filing date: 1946-03-20
Publication date: 1950-09-19
Anticipated expiration: 1967-09-19

Description

Patented Sept. 19, 1950 FFICE HEAT EXCHANGE]! I George. A. Worn, Greenwich, Conn., assignor to The Lnmmus Compan poration ofDelaware y, New York, N. Y., a cor- Application March 20, 1940, Serial No. 655,824

2 Claims. (01. 257-32) This invention relatesmore particularly to improvements in a subcooler constructiondor heat exchangers of the shell-and-tube type.

A certain type of subcooler construction includes a tubular longitudinal baffle of the bundle wrapper type. In a heat exchanger having a plurality of tube passes and wherein a heated fluid is passed through the shell and a coolin fluid is passed through the tubes, such a baflle is employed to conduct the shell-side fluid, in its final cooling stage, along the coldest tubes of the exchanger. For that purpose, the bafileis arranged to enclose a group of tubes included in the first pass and to conduct the shell-side fluid along the enclosed tubes to a discharge point remote from the point where the fluid enters the baflle. For discharge of the fluid, the baflle is provided with a transverse nozzle which is attached to the bafile and projects outwardly through another nozzle welded to the side of the shell. Such a construction greatly complicates the manufacture and servicing of the exchanger. The discharge nozzle cannot be attached to the bafile until the latter has been inserted into the shell, along with the tube bundle, nor can the bundle and the battle be removed without first breaking the connection between the nozzle and the baflle. Owing to the fact that the space available for making and breaking the connection is quite limited and difficult to reach, both operations are extremely laborious and time consuming.

The main object of my invention is to provide in a heat exchanger a positive and tight connection between an internally ballied space and an external nozzle, whereby fluids may be introduced to or removed from the bafiled space without leaks, and whereby the shell may be readily channel, which will permit full communication between the baflled section and nozzle with a minimum of loss of tubes and with a -minimum structural cost.

Further objects and advantages of the inven- I tion will appear from the following description taken in connection with the accompanying drawing.

In the drawing:

Fig; '1 is a vertical longitudinal section of a heat exchanger embodying the invention;

Fig. 2 is a side elevation of the upper portion of the exchanger;-

Fig. 3 is a horizontal sectionon the line 3-3 of Fig. 1;

Fig. 4 is a detail sectional view on the line 4-4 of Fig. 1;

Fig. 5 is a detail sectional view showing a modifled form of the invention; and

.Fig; 6 is a section on the line 6-8 of Fig. 5;

The invention is shown as embodied in a vertically disposed heat exchanger unit but it is equally well adapted for embodiment: in a unit arranged horizontally or otherwise.

Referring to Figs. 1 to 4, inclusive, the structure of the heat exchanger includes a vertical shell I having an outwardly extending flange 2 at its upper end. As shown, said flange may be formed on an annular section 3 welded to the body of the shell, as at l. "The lower end of the shell is dome-shaped and provided with a drain cock 5. A nozzle 6 for entry or discharge of shell-side fluid is welded to the shell adjacent the upper end of the latter.

A channel structure I is mounted upon the upper end of the shell and includes a flat bottom portion and upstanding annular body portion 8.

Said bottom portion forms a tube sheet 9 and an outwardly extending flange III. This flange overlies the shell flange 2. A gasket II is interposed between the flanges 2 and I0, and bolts l2 pass through said flanges and releasably secure the channel structure to the shell. A closure plate It is fitted within the upper portion of the body of the channel and secured by any suitable looking and sealing structure, such as that disclosed in Patent No. 2,268,507 of Gertzon, for example. In such case the annular channel wall is formed with an internal groove H. A split locking ring l5 has a peripheral portion thereof projecting into said groove, and a backing ring I6 is fitted within the lockingring to .hold the latter expanded. recessed to accommodate said rings. The upper faces of the channel and the closure plate are substantially flush and a gasket I'l overlaps both of said faces. A pair of concentric clamping rings l8 and I9 bear against the gasket. The ring I8 is secured to the channel by bolts 20, and the ring I9 is secured to the closure plate by bolts 2|. This sealing member forms no part of the present invention, however. I

' A partition 22 divides the channel space into two

compartments

23 and 24 respectively. An inlet nozzle 25 welded to the channel opens into the compartment/23, and an outlet nozzle 26 welded to the channel leads from the compartment 24. A bundle of U-tubes :1 depends from The closure plate is peripherally.

the tube sheet 9 into the shell. One leg of each tube opens into the inlet compartment 23 and the other leg opens into the outlet compartment 24 of the channel. The legs opening into the com-'- partment 23 define one pass of the tube-side circulation, and the legs opening into the compartment 24 define the other pass. The direction of flow determines which pass is first and, as shown, the tube fluid enters at 23 so that tubes entering such compartment are the first pass tubes.

The improved-\construction where used as a subcooler includes a tubular bailie 28. This battle is welded, as at 29, to the under face of the tube sheet 9, and depends therefrom into the shell to a point adjacent the bend of the tubes. A group of tubes of the first pass are surrounded by the baffle, the cross-section ofwhich may be of any suitable shape, depending upon the number of tubes to be enclosed and upon space limitations. In the present instance, the cross-section of the bafile is triangular at its inner side to follow the lay of the tubes, and arcuate at its outer side to conform to the shell shape. The lower end of the baffle is open to admit the shell-side fluid, and the interior of the baflie may be provided with a vertical series of transverse bailies 30 in staggered arrangement to cause a circuitous flow of the admitted fluid along the enclosed tubes.

The principal feature of my invention is the provision for discharge of the fluid from the interior of the baflle 28. For that purpose, the channel structure I is preferably provided with one or more passages 3l extending through the tube sheet 9 and upwardly within the thickness of the annular wall of the channel structure.

An outlet nozzle 32 is welded into a bore or aperture in said channel wall, and said passages 3| open laterally at their upper ends into said nozzle. At their lower ends the passages 3| communicate directly with the upper end of the space enclosed by the bafile 28, so that the shellside fluid may flow from said space through the passages 3i and the nozzle 32 to the exterior of the heat exchanger. A plurality of the passages 3| of relatively small diameter are provided in preference to a single passage of greater diameter in order to afford adequate discharge capacity without the necessity of making the wall of the channel excessively thick.

- In operating the heat exchanger as a subcooler, heated fluid in either vapor or liquid phase enters the shell through the nozzle 6, and cooling fluid enters the tubes of the first pass through the nozzle 25 and the channel compartment 23 and flows downwardly through the tubes of said pass and then upwardly through the tubes of the second pass. Thence, the cooling fluid leaves the exchanger through the channel compartment fluids could be arranged if desired.

In the form of the invention shown in Figs. 5 and 6, a single passage 3la through the tube not penetrate the channel wall. v A horizontal bore 33 is formed in the channel wall above the tube sheet and an outlet nozzle 32a is welded to said wall in alignment with said bore.

To complete the fluid path a hood-shaped element 34 is disposed in the angle between the tube sheet 9 and the channel wall. This element has a U-shaped lower edge welded to the tube sheet, around the margin of the passage Ila, and a U-shaped vertical edge welded to the channel wall. An elbow connection is thus formed .betweenthe passage 3m and the bore 33 for passage of fluid from the baflie to the nozzle 32a and the exterior of the heat exchanger. When it is possible or convenient to form a part of bore or passage 3Iain the wall 8, the hood element 34 may be smaller (lesser radius), thus interfering with fewer cooling tubes 21.

Both forms of the invention provide a subcooler outlet conduit embodied entirely in the channel structure and independent of the shell. It is also entirely clear of the shell so that there is no obstruction to insertion or removal of the tube bundle. By extremely simple structural alteration, the diificult and time-consuming labor in assembly and disassembly caused by the usual sheet affords egress from the space within the bafiie 28. This passage is located inwardly of the channel wall and in this arrangement does subcooler construction is entirely eliminated.

While the invention has been shown and described in connection with a subcooler feature, its utility is .by no means limited to a subcooler. For example, it is readily adaptable to a desuper- ,heater feature for a heat exchanger employed to heat a fluid within the tubes by circulation of steam within the shell. For that service, the bafiie 28 can be mounted to enclose tubes of the second or outgoing pass instead of the first pass,

and the

nozzle

32 or 32a and the conduit con necting the nozzle to the interior of the bafile may be disposed in the same relation to the bafiie as that previously described herein. Then, superheated steam may be passed through the nozzle and the conduit to the interior of the bailie, and be desuperheated therein as it is conducted along the confined tubes.

It is, of course, to be understood that the present disclosure of my invention is merely illustrative and in 'nowise limiting, and that the invention comprehends such modifications as will come within the scope of the following claims.

I claim:

1. A heat exchanger comprising a vertical shell closed at its lower end; a vertical tube bundle therein; means for directing a fluid through the tube bundle in a plurality of passes and including a channel structure at the upper end of the shell and comprising a tube sheet for the bundle releasably secured to the upper end of the shell, an annular channel body having pass partition means therein, and an outer closure for said body; a vertical tubular bafiie surrounding tubes of one of the passes and welded around the upper edge thereof to said tube sheet for leakproof connection therewith, said bafiie extending from the portion of said baffle upwardly through said tube sheet and laterally outward .below said closure to an outer wall of the channel structure and placing the space within said baille in communication with the exterior of the exchanger, the tube bundle, the channel structure, the said baflle and the said conduit forming a unit separable from the shell after release of the channel structure from the shell.

2. A heat exchanger comprising a vertical shell; 2. vertical tube bundle therein, means for directing a fluid through the tube bundle in a plurality of passes and including a channel structure at the upper end of the shell and comprising a tube sheet for the bundle releasably secured to the upper end of the shell, an annular channel body having pass partition means therein, and

an outer closure for said body; a vertical tubular baflle surrounding tubes of one of the passes and welded around the upper edge thereof to said tube sheet for leakproof connection therewith,

closed at its upper end, and a port extending from the upper end portion of said element laterally through said channel body to the outer periphery of the latter, said conduit element being entirely below the channel closure and being welded at its lower edge to the tube sheet and welded along its side edges and its top edge to the inner face of the channel body, all of said welding being continuous and rendering the conduit leak-proof,

the tube bundle, the channel structure, the saidbafile and the said conduit forming a unit separable from the shell after release of the channel structure from the shell.

GEORGE A. WORN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 698,290 Kelley Apr. 22, 1902 729,400 Patterson May 26, 1903 1,954,356 How Apr. 10, 1934 2,060,078 Hobbs Nov. 10, 1936 2,376,505 Rathbun et al. May 22, 1945 2,411,436 Kopp Nov. 19, 1946 2,412,573 Fraser, Jr. Dec. 17, 1946