US2489944A

US2489944A - Heat exchanger

Info

Publication number: US2489944A
Application number: US724164A
Authority: US
Inventors: George A Worn; Jr George W Evans
Original assignee: Lummus Co
Current assignee: CB&I Technology Inc
Priority date: 1947-01-24
Filing date: 1947-01-24
Publication date: 1949-11-29
Anticipated expiration: 1966-11-29

Description

Nov. 29, 1949 5, WORN ETAL HEAT EXCHANGER Filed Jan. 24, 1947 I N V EN TORS 1 Patented Nov. 29, 1949 HEAT EXCHAN'GER.

George A. Worn, Greenwich, Conn., and George W. Evans, Jr., Teaneck, N. J assignors to The Lummus Company, New York, N. Y., a corporation of Delaware Application January 24, 1947, Serial No. 724,164

6 Claims.

This inventlon'relates to improvements in a subcooler construction for heat exchangers of the shell-and-tube type.

A certain type of subcooler construction includes a tubular longitudinal bafile 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 cooling fluid is passed through the tubes, such a baille is employed to conduct the shell-side fluid, in its final cooling stage, along the coldest tubes of the exchanger. For that purpose, the baffle is 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 bafile is provided with a transverse nozzle which is attached to the baffle 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 bafile 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 difflcult to reach, both operations are extremely laborious and time consuming.

A copending application of George A. Worn, Serial No. 655,824, filed March 20, 1946, discloses, in a vertical heat exchanger having a channel structure at the upper end of the shell and a bundle of U-tubes depending from-said structure, a

subcooler feature having a discharge connection embodied within the channel structure and clear of the shell in order to facilitate assembly and disassembly of the exchanger. An important object of the present invention is to provide, in a vertical heat exchanger having the channel at the lower end of the shell and a tube bundle projecting from the channel upwardly within the shell and provided with a floating head, an improved subcooler construction also having a discharge connection embodied in the channel and affording the aforesaid advantages in assembly and disassembly.

A further object of the invention is to provide in such a heat exchanger an improved subcooler baffle construction.

A still further object of the invention is to provide, in combination with the subcooler baffle construction, an improved vent feature.

Fig. 2 is a horizontal section on the line 2-2 of Fig. l; and

Fig. 3 is a detail sectional view on the line 3-3 of Fig. 2.

The structure of the heat exchanger includes a vertical shell I having an outwardly extending flange 2 at its lower end. As shown, said flange may be formed on an annular section 3 welded to the body of the shell as at 4. The upper end of the shell is dome-shaped. A nozzle 5 for entry of shell-side fluid is welded to the shell at a high point of the latter.

A channel structure 6 is secured to the lower end of' the shell and includes a flat upper wall portion and a depending annular body portion I. Said upper wall portion forms a tube sheet 8 and an outwardly extending flange 9 underlying the shell flange 2. A gasket I0 is interposed between the flanges 2 and 9 and bolts ll pass through said flanges, outwardly of the gasket, and releasably secure the channel structure to the shell. A closure plate [2 is fitted within the lower portion of the body of the channel and secured by any suitable locking and sealing structure,

such as that disclosed in Patent No. 2,268,367 of Gertzon, for example. In such case the channel wall is formed with an internal groove IS. A split locking ring I4 has a peripheral portion thereof projecting into said roove, and. a backing ring I5 is fitted within the locking ring to hold the latter expanded. The closure plate is peripherally recessed to accommodate said rings. The under faces of the channel and the closure plate are substantially flush and a gasket l6 overlaps both of said faces. A pair of concentric clamping rings l1 and I8 bear against the gasket. The ring I! is secured to the channel by bolts l9, and the ring i8 is secured to the closure plate by bolts 20. The particular sealing means disclosed however, forms no part of the present invention.

A partition 2| divides the channel space into two compartments 22 and 23, respectively. An inlet nozzle 24 welded to the channel opens into the compartment 22, and an outlet nozzle 25 welded to the channel opens from the compartment 23. A bundle of straight vertical'tubes 26 extend from the channel tube sheet 3 upwardly within the shell. These tubes have their lower ends rolled into the tube sheet 8, and a floating head structure 21 is connected to the upper ends of the tubes. The floating head structure comprises a flat bottom wall forming a tube sheet 23 into which the upper ends of the tubes are rolled,

a vertical vent pipe 40 has its lower end rolled into an aperture in the lower tube sheet 8 and extends upwardly to a point near the upper tube sheet 28. The lower tube sheet has a counterbore 4! into which the lower end'of the vent pipe opens, and a plug 42 is screwed into the lower end of said counterbore. A vent passage 43 leads and an upstanding annular wall 29. A closure plate 30 is fitted into the upper portion of the wall 39 and secured and sealed by means similar to that employed for securing and sealing the channel closure plate l2. In the drawing the parts of the floating head sealing means corresponding to those of the channel sealing means are correspondingly numbered, and primed. Some of the tubes opening into the floating head lead from the inlet compartment 22 of the channel and constitute the first tube pass, and others of the tubes lead from the floating head to the channel outlet compartment 23 and constitute the second and final tube pass. Of course, the number of passes may exceed two.

The subcooler structure includes an upstanding tubular baffle 3!. In the present instance this ballle surrounds a portion only of said tubes of the first pass. However, it may be constructed and arranged to surround all of the tubes, of said pass. The baille is welded, as at 32, entirely around its lower edge to the upper face of channel tube sheet 8, and the upper end of the bailie is spaced below the floating head tube sheet 28. Transverse baffles 33 in vertically spaced staggered arrangement are provided within the baffle 3i. A depending tubular baffle 34, larger than the baiile 3 I, surrounds the latter and affords substantial flow space therebetween. Baflle 34 is welded, entirely around the upper edge thereof, to the under face of the floating head tube sheet 28, as at 35. The lower end of the baflle is spaced above the channel tube sheet 8. In the present instance the baifies 3| and 34 are of segmental form in cross-section but they may be of other form.

The provision of two tubular bafiies in telescoped arrangement avoids the necessity of an expansion joint connection with the floating head, entailed by employment of a single baflie. Such a joint is diificult to reach and repair in case of rupture thereof and requires disassembly of the exchanger whereas the double baflle feature of our invention enables the floating head to rise and fall as the tubes expand and contract without strain upon any connection.

Another feature of our invention is the provision for discharge of the shell-side fluid from the interior of the inner tubular baflle 3i. For that purpose, the channel structure 6 embodies a discharge conduit which is independent of the shell. This conduit is defined by a vertical port 36 in the tube sheet 8, a lateral port 31 in the annular wall I of the channel, and a hood-shaped element 38 disposed in the angle between the tube sheet and the channel wall. This element has a. U- shaped upper edge welded to the tube sheet around the margin of the port 36, and a U-shaped vertical edge welded to said channel wall around the port 31. An elbow connection is thus formed for passage of fluid from the bottom of the space surrounded by the baflie 3| to the port 31. A nozzle 39 is welded to the wall 1 to receive the fluid passed through the port 31 and discharge it from the exchanger.

Another feature of our invention is a provision for venting the space within the upper portion of the outer tubular baflle 34. For that purpose,

from the counterbore laterally outwardly through the tube sheet to the outer edge of flange 9. Thereby said upper portion of the baffle space is vented through a passage which is also independent of the shell.

In operating the exchanger heated fluid in either vapor or liquid phase enters the shell through the nozzle 5 and cooling fluid enters the tubes of the first pass through the nozzle 24 and the channel compartment 22 and flows upwardly through the tubes of said 'pass to the floating head and thence downwardly through the tubes of the second pass to the channel compartment '23 and out through the nozzle 25. The shell-side Thence the shell-side fluid, in liquid phase, passesv upwardly between the tubular'batlies 3| and 34 into the upper end of the inner bafile 3i and downwardly through the latter. Thereby said fluid is subcooled by contact with the coldest tubes of the bundle.

The subcooled liquid is then discharged through the port 36, the elbow connection 38 and the nozzle 39. Other arrangements of fiowof liquid can be made if desired. Venting of the space within the upper portion of baflie 33, through pipe 40 and passage 43, prevents an air or vapor trap which would impede flow into; the subcooler bafile 3|.

The tube bundle and the shell may be readily separated for servicing. After release of the bolt connections II the channel and tube bundle, together with the floating head, may be withdrawn through the lower end of the shell, or, the shell may be withdrawn from the bundle. Since the discharge connections for the subcooler and for the vent are both embodied in the channel structure and are disposed entirely clear of the shell they form no obstruction to separation of the bundle and the shell.

While the invention has been shown and described in connection with a subcooler feature its utility is by no means limited to a subcooler.

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

We claim:

1. In a heat exchanger including a vertical shell having a fluid inlet, a vertical tube bundle within the shell and means for directing fluid in a plurality of passes through the tubes of the bundle and comprising a channel structure at the lower end of the tube bundle and releasably connected to the shell and including a tube sheet forthe bundle, and a floating head connected to the upper end of the bundle; the improvement comprising a tubular bai'fle borne by and extending upwardly from said tube sheet and surrounding tubes of one of said passes and terminating below said floating head, said bailie being open at its upper end only for admission of shell-side fluid, a tubular baiile borne by and depending from said floating head and telescoped over a substantial length of the flrstmentioned baille, with flow space therebetween,

and terminating above said tube sheet, the second-mentioned baflle being open at its lower end only for admission of shell-side fluid and being movable vertically relatively to the first-mentioned baflle by movement of the floating head in response to expansion and contraction of the tubes, said baflies defining a passage to conduct shell-side fluid upwardly therebetween and thence downwardly along the tubes within the inner one of the baflies and said channel structure having a conduit therein independent of the shell and arranged to conduct said shell-side fluid from the lower end of said inner bafile to the exterior of the heat exchanger, and a vent pipe extending from said tube sheet upwardly within one of said baffles to a point adjacent the floating head, the channel structure having a vent passage leading from said pipe to the exterior of the exchanger.

2. In a heat exchanger including a vertical shell having a fluid inlet, a vertical tube bundle within the shell and means for directing fluid in a plurality of passes through the tubes of the bundle and comprising a channel structure at the lower end of the tube bundle and releasably connected to the shell and including a tube sheet for the bundle, and a floating head connected to the upper end of the bundle; the improvement comprising a tubular baflle borne by and extending upwardly from said tube sheet and surrounding tubes of one of said passes and terminating below said floating head, said baffie being open at its upper end only for admission of shell-side fluid, and a tubular baffle borne by and depending from said floating head and telescoped over a substantial length of the first-mentioned baiile, with flow space therebetween, and terminating above said tube sheet, the secondmentioned bafile being open at its lower end only for admission of shell-side fluid and being movable vertically relatively to the first-mentioned battle by movement of the floating head in response to expansion and contraction of the tubes, said bailies defining a passage to conduct shell-side fluid upwardly between the baflles and thence downwardly along the tubes within the inner one of the baiiles and said channel structure having a conduit therein independent of the shell and arranged to conduct said shell-side fluid from the lower end of said inner baiile to the exterior of the heat exchanger.

3. In a heat exchanger including a vertical shell having a fluid inlet, a vertical tube bundle within the shell and means for directing fluid in a plurality of passes through the tubes of the bundle and comprising a channel structure at the lower end of the tube bundle and releasably connected to the shell and including a tube sheet for the bundle, and a floating head connected to the upper end of the bundle; the improvement comprising a tubular bafi'le borne by and extending upwardly from said tube sheet and surrounding tubes of one of said passes and terminating below said floating head, said baflle being open at its upper end only for admission of shell-side fluid, a tubular baflle borne by and depending from said floating head and telescoped over a substantial length of the first-mentioned baiiie, with flow space therebetween, and terminating above said tube sheet, the second-mentioned baflle being open at its lower end only for admission of shell-side fluid and being movable vertically relatively to the first-mentioned baflle by movement of the floating head in response wardly along the tubes within the inner one of the battles and said channel structure having a conduit therein independent of the shell and arranged to conduct said shell-side fluid'from the lower end of said inner battle to the exterior of the heat exchanger, and a vent conduit independent of the shell and leading from the space within the upper end of the outer one of said baffles to the exterior of the exchanger.

4. In a heat exchanger including a ve tical shell having a port opening to the exterior of the exchanger, a vertical tube bundle within the shell and means for directing fluid in a plurality of passes through the tubes of the bundle and comprising a channel structure at the lower end of the tube bundle and releasably connected to the shell and including a tube sheet for the bundle, and a floating head connected to the upper end of the bundle; the improvement comprising a tubular bafile borne by and extending upwardly from said tube sheet and surrounding tubes of one of said passes and terminating below said floating head, and a tubular balile borne by and depending from said floating head, telescoped over a substantial length of the firsttively to the first-mentioned battle by movement of the floating head in response to expansion and contraction of the tubes, said bafiies defining therebetween a conduit open at its lower end to the shell space exterior to the bafiles and open at its upper end to the interior of the inner one of the baflles, and said channel structure having a conduit'therein independent of the shell and open at one end to the space within the lower end of said inner baille and open at its opposite end to the exterior of the heat exchanger.

5. In a heat exchanger including a vertical shell having a fluid inlet, a vertical tube bundle within the shell and means for directing fluid in a plurality of passes through the'tubes of the bundle and comprising a channel structure at the lower end of the tube bundle releasably connected to the shell and including a tube sheet for the bundle, and a floating head connected to the upper end of the bundle; the improvement comprising a tubular bafile borne by and extending upwardly from said tube sheet and surrounding tubes of one of the passes and terminating below said floating head, a tubular baffle borne by and depending from said floating head telescoped over a substantial length of the between a conduit open at its lower end to the shell space exterior to the bailies, and open at its upper end to the interior of the inner one of the bailles, and a conduit leading from the lower portion of the space within the inner baffle to the exterior of the exchanger.

6. In a heat exchanger including a vertical shell having a fluid inlet, a vertical tube bundle within the shell and means for directing fluid in a plurality of passes through the tubes of the bundle and comprising an externally cylindrical channel structure at the lower end of the tube bundle releasably connected to the shell and including a tube sheet for the bundle, and a floating head connected to the upper end of the bundle; the improvement comprising a tubular bafiie borne by and extending upwardly from said tube sheet and surrounding tubes of one of the passes and terminating below said floating head, a tubular baffle borne by and depending from said floating head and telescoped over a substantial length of the first-mentioned baille, with flow space therebetween, and terminating above said tube sheet, the first-mentioned baffle being open at its upper end to the interior of the second-mentioned baffle and the second-mentioned baffle being open at its lower end only to the interior of the shell and being movable vertically relatively to the first-mentioned bafile by movement of the floating head in response to expension and contraction of the tubes, said baffies defining therebetween a conduit open at its lower end to the shell space exterior to the baflles and open at its upper end to the interior of the inner one of the baflles, a conduit independent of the shell and within the cylindrical confines of the channel structure and leading from the lower portion of the space within the inner bafile through the channel structure to the outerside wall of the latter, and a nozzle borne by and extending outwardly directly from said wall and continuing said conduit to the exterior of the exchanger.

GEORGE A. WORN.

GEORGE W. EVANS, JR.

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

UNITED STATES PATENTS Number Name Date 1,954,356 How Apr. 10, 1934 2,381,006 Scott, Jr. Aug. 7, 1945 2,412,573 Fraser, Jr. Dec. 17, 1946