US1935066A - Heat exchanger - Google Patents

Description

2 Sheets-Sheet 1 ATTORNEY R. M. SWARTZ ET AL HEAT EXCHANGER Filed Dec. 51. 1931 Nov. 14, 1933.

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HEAT EXQHANGER Filed Dec. 31, 1931 2 Sheets-Sheet 2 ATTORNEY Patented Nov. 14, 1933 UNITED STATES HEAT EXCHANGEB Ralph M. Sta... Bogota, N. 1., and Carl s. Reed, New York, N. Y.; said Swartz assignor to The Superheater Company, New York, N. Y.

Application December 31, 1931 Serial No. 584,238

14 Claims.

Our invention relates to the art of heat exchange and aims to provide a heat exchanger adapted to handle liquid at high pressures.

In the oil industry it has become common to utilize heat exchangers to recuperate latent heat in vapors given oif from cracking and distilling chambers by cooling such vapors with liquid moving toward the cracking or distilling chambers. Such liquid is often under high pressure,

especially in installations of the cracking type, while it is essential to provide clean-out joints at the ends of the tubular elements in which the liquid is .heated in order to maintain their thermal efficiency. Such clean-out joints are usually of expensive design because the heat exchangers are often placed in high pressure lines and the joints must be tight against hot oil to prevent danger of fire. Moreover, a shut-down involves heavy expense for each hour the plant I is out of operation.

It is an object of our invention to provide a design adapted to minimize the cost of high pressure heat exchangers and. the length of a shutdown for cleaning a heat exchanger.

The novel features of our invention are point-- ed out in the appended claims. The invention itself, together with its object and advantages,

will best be understood, however, from a detailed description of an apparatus in accordance with the invention, and such a description will now be given in connection with the accompanying drawings of a heat exchanger selected by way of example from a number of possible emb'odiments of the invention.

In-the drawings Fig. Us a central longitudinal section of a heat exchanger in accordance with the invention.

Fig. 2 is a section on line 2-2 of Fig. 1 looking in the direction of the arrows.

Fig. 3 is a section on the line 3-3 of Fig. 1 looking in the direction of the arrows.

The apparatus illustrated in the drawings comprises an outer shell 10 having a ring 12 at one end thereof and a portion 14 connected to ring 45 12 by a readily disconnectable joint 16. Vapors for heating are introduced into shell 10 through inlet 18 in ring 12 and discharged from the shell through outlet 20, also in such ring. Supported within shell 10 is a group 22 of tubular units 24, 24 through which the liquid to be heated is passed. Each of the units 24 is of serpentine form lying in a substantially given plane, the units 24 of group 22 all having their planes arranged substantially parallel. Owing to their serpentine 55 form, units 24 have considerable flexibility to accommodate expansions and contractions due to changes in temperature. Along one side of each unit 24 is a row of retiu'n bends 26, 26 connecting straight pipe lengths or runs of the units. 00 In the arrangement illustrated, shell 10 is ar ranged'with its axis vertlcaland the bends 26 at the upper sides of units 24. This fact is utilized in the arrangement shown to provide means for lifting the group 22 as a whole or unit so that it can be quickly taken from the exchanger and a clean group put in its place whenever it is necessary to clean the group of units. The time during which it is necessary to shut down the plant to clean the heat exchanger is thereby reduced to a minimum. As illustrated for this purpose, each bend 26 has fixed thereto an upward extension 28. The upper end of each such extension is threaded to receive a nut 30 whereby bar 32, shown as an angle, may be secured to each unit 24. The bars 32 are all connected together into a framework by cross bars 34, 34, also shown as angles, and the frame so provided has lifting eyes 36, 36 therein by which the whole group 22 may be hoisted as a unit from the ring 12 when the joints of the fluid connections for the units have been broken. The portion 14 of the shell also has eye members 38, 38 fixed thereto whereby it may be lifted from ring 12 when the joint 16 has been broken.

The units 24 have jointed connections at their ends with header blocks 40, 40. Preferably the joints between units 24 and blocks 40 are of the ground'cone type illustrated at 42. However,-we do not limit ourselves to this. It will be understood that the ends of units 24 are clamped to blocks 40 by suitable means, not shown, which are well understood and commonly used in connection with such joints. The blocks 40, and thereby the group 22, are supported when. in use on supporting brackets 44, 44 of triangular form in plan which are fixed to the inner face of ring 12. The upper triangular faces of the brackets 44 are shown as contacting with the under faces of the headers 40. Brackets 44 extend beyond one edge of ring 12 so that the undersides of blocks 40 are readily accessible wheneverportion 14 has been removed from 12. The utility of this feature will appear hereinbelow.

Liquid to be heated in units 24 is introduced into the shell 10 through heavy blocks 50, 50 which extend through the wall of ring 12. Blocks 50 are shown as welded into ring 12 as indicated at 52 so that there shall not be any leakage through the shellaround the edges of the blocks. Passageways 54, 54 are provided through blocks 50 for inlet and outlet respectively of liquid to be heated. Suitable means, not shown, may be used for connecting pipes for liquid at the ends of the passageways 54 outside the shell 10. At the ends of passageways 54 within shell .10, means-shown at 5'6, 56, (Fig. 2) are provided for making a liquid tight joint between the blocks 50 and tubular connections 58, 53 for liquid, one of which extends from each block 50 to a joint on the under side of one of the header blocks40. As illustrated,

each connection 58 extends within ring 12 around beneath the lower end of group 22 for a material part of 360 deg. and the blocks 40 are placed some distance above the blocks 50 so that the connections 58 can curve up gradually from one set of blocks to the other. The connections 58 thereby have suflicient flexibility to readily accommodate themselves to expansions and contractions of the various parts due to changes in temperature. The connections 58 and blocks 50 are expected usually to remain in place whereas the joints 60 between the upper ends of connections 58 and the blocks 40 will be broken whenever it is desired to remove a group 22 from the ring 12. Joints 60 are so designed that they may be readily broken and reassembled without danger of causing leakage. We have illustrated joints 60, however, as of a well known type as we do not limit ourselves to any particular form of joint. While there is seldom need to disturb the joints between blocks 50 and connections 58, such joints are preferably like joinrts 60 and are so placed that connections 58 may be readily removed when desired. From the joints 60 connections are made between the tubes 58 and the elements 24 through the blocks 40 by passages 62 and 64 within such blocks.

It will be seen that the group 22 of tubular elements has a rectangular, preferably a square cross-section. See Figs. 2 and 3. It is preferred, however, that the shell 10 be circular. The vacant segments between the inner surface of shell 10 and the group 22 must therefore be filled in to prevent much of the heating fluid from passing through the shell without contacting with units 24. For this purpose we have shown flat longitudinally extending plates 65, 65 along the sides of the group 22, two of the edges of each plate 65 being joined to portion 14 of the shell along rectilinear elements thereof. The segmental spaces defined by plates 65 are closed at one end, or both ends, to prevent passage of gases therethru, transverse plates 65a, 65a preferably being used for this purpose at the upperends of plates 65. At their lower ends, plates 65 are shown as bent toward the shell to provide room for the The heat may be abstracted from the vapors or gases in either a multipass or single-pass arrangement in accordance with our invention. As shown, we have provided two passes for the heating fluid within shell 10 by arranging a central bafile plate 100 extending along the central axis of shell 10 from the closed end of ring 12 to a point near the end of group 22 removed from ring 12. Plate 100 preferably extends entirely across the shell 10 along the diameter thereof and cuts through the plates 65, although this feature is immaterial to the invention. The battle 100 is intended to remain in place when the group 22 is removed from ring 12 and plates 65 have means, shown in the form of curved somewhat resilient lips 10,2, 102, for permitting plates 65 to slide on plate 100 and for preventing leakage of gas from the gas passes into and out of the closed segments at two sides of the gas passes. The portion 14 of the shell is movable with respect to plate 100, and we prefer to employ a gas tight joint between plate 1"! and portion 14. We have illustrated a joint between parts 100 and 14 of the same type as those between plate 100 and plates 65. This is a matter of convenience only. As shown, two pairs of lips 104, 104 are welded to portion 14 so as to embrace the edges of plate 100 to prevent leakage between plate 100 and the portion 14 of the shell. Similar lips, not shown, are employed on the ring 12 for the same purpose. The end plate 106 which closes the ring 12 is also provided with means making a gas tight joint with plate 100. Lips 104a, 104a are illustrated for this purpose. It will be seen that the joints at the edges of plate 100 permit its ready removal from shell 10 when desired without disturbing the group 22, by simply removing the end plate 106. It will be seen further that liquid connections 58 do not pass through plate 100,.but lie one on one side of said plate and one on the other, whereby plate 100 may be removed and replaced without interfering with connections 58. Such arrangement furthermore avoids joints in the plate 100. To permit liquid to pass from one side of plate 100 to the other when the heating fluid used is primarily vaporous, a trap pipe 108 is shown having its ends passing through plate 106 at points on opposite sides of plate 100.

It is preferred also to employ a perforated baflle 110 on the inlet side of plate 100 and so arranged as to direct some of the fluid entering through inlet 18 first downward so that it may enter group 22 near the end of the group and to prevent direct impact on the clean-outs mentioned hereinbelow. We prefer further to employ means to ensure the portion 14 of shell 10 shall fit together without difiiculty when these parts are being assembled. For such purpose we have illustrated a heavy pin 111 fixed to the centre of the closed end of portion 14 and adapted to enter an aperture 112 in a block 114 fixed to group 22 so that the portion 14 will be held in proper position to make a tight joint with ring 12 as the parts are brought together. The outer portion of aperture 112 is beveled as shown at 116 to facilitate entry of the pin 111 into aperture 112. As illustrated, block 114 is fixed to flanges 118 on two of the cross-bars 34 at one end of group 22.

At one side of each of units 24 there is shown a row of return bends 66, 66 each of which has a tubular clean-out 68 extending therefrom and having a closure fitting 70 thereon of known type. Each of the fittings 70 includes a plug member, not shown, which may be readily removed when it is desired to clean out the pipe runs of the units.

The clean-outs are shown at the bottoms of units 24, but we do not limit ourselves to this. Also, clean-outs may be placed along both sides of units 24, if desired.

It will be seen that an exchanger in accordance with our invention avoids the necessity of rolling joints into heavy tube sheets thereby reducing the expense of manufacture, while the parts are so designed as to permit them to expand and contract with the changes of temperature without serious internal stresses or danger of loosening the joints to cause leakage. Our heat exchanger may, moreover, be readily disassembled by merely breaking the joint 16 in the shell and the two joints 60, it being thereupon easy to remove a group of heating units and substitute another in a minimum of time.

While we have described our novel heat exchanger as applied to heating oil for distilling and cracking installations, we do not limit ourselves to any particular field of use for our invention.

While we have illustrated and described above in detail an apparatus having only a single baflle within the tube bank 22, it is evident that we may use as many such bailies as necessary to provide the desired number of passes for the gases provided only there is one row of tube runs in each pass.

Furthermore, in order to satisfy the best purposes of any particular design the two fluid mediums may be arranged in parallel flow, counter flow, cross flow or a combination thereof.

What we claim, is:

1. A heat exchanger having a shell composed of a ring and a portion releasably connected thereto, said ring having vapor inlet and outlet openings and means forming liquid inlet and outlet openings therethrough, a group of tubular units within'said shell, a support for said group carried on'said ring, connections for conducting liquid between said liquid inlet and outlet and said units, and means forming readily separable joints between said connections and said units.

2. A heat exchanger having a shell including a ring at one end thereof and a portion readily separable therefrom, said ring having vapor inlet and outlet openings therethrough, a set of tubular heating units within said shell, a support for said units on said ring, liquid inlet and outlet connections for said units extending through said ring, means whereby said connections may be readily disconnected from said units, and means whereby said units may be removed simultaneously when said portion has been removed from said ring.

3. A heat exchanger having a group of tubular units therein for liquid to be heated, said units,

each having a bend at two opposite sides, projections fixed to the bends at one side of said units, and a frame tying said projections together whereby said group may be lifted as a whole.

r. A heat exchanger as set forth in claim 3 and in which the bends of the units at their side opposite the lifting frame have tubular clean-out extensions thereon.

5. A heat exchanger having a cylindrical shell provided near one end with an inlet and an outlet for heating vapors, a group of tubular units in said shell and havinga rectangular outline in cross-section, baffles along opposite sides of said group, and a third baflle arranged centrally of said group and extending from the end of the shell having said inlet and said outlet away therefrom to a point not so close to the other end of said shell as said two side baiiies.

6. A heat exchanger having a shell including a ring at one end thereof and a portion readily separable from said ring, a group of units within said shell for liquid to be heated, said ring having a vapor inlet and outlet therein and blocks extending therethrough and providing an inlet and outlet for liquid for said units, header blocks for said units within and unconnected with said shell, and liquid connections between said first blocks and said header blocks and having means forming a readily disconnected joint between themselves and the headers.

7. A heat exchanger as set forth in claim 6 I and in which the liquid connections both curve and extend longitudinally whereby expansion and contraction of the parts is accommodated.

8. A heat exchanger as set forth in claim 6 and in which brackets for supporting the group of units are fixed to the inner face of the ring and extend laterally therefrom to contact with the headers for the units and thereby support the 9. A heat exchanger as set forth in claim 6 and in which the liquid connections lie at one end of the group of units together with, a baflie extending centrally of the group of units from the end of the shell having the ring nearly to openings of which said inlet is in said ring, said ring also. having liquid inlet and outlet openings therein, a group of tubular units within said shell, said group and said ring being arranged so that the units are supported from the ring, means for conducting liquid located between said liquid inlet'and outlet and said units and means forming readily separable joints between said first means and said units.

11. A heat exchanger having a shell including a base ring and a portion releasably connected thereto, said ring having a vapor passage therein and having also apertures for the inlet and discharge of liquid, a pair of headers, one arranged to receive liquid thru said inlet aperture and one to discharge liquid thru said discharge aperture, means for supporting said headers from said ring, a plurality of serpentine units supported from said ring and extending upwardly into said releasable portion of the shell, said units having each a return bend at top and at bottom, said bottom bend having a clean-out associated therewith, and means forming readily separable joints between said headers and said units.

12. A heat exchanger having a group of serpentine tubular units therein, said units having each a plurality of bends at its top and at its bottom, projections fixed to the bends at the tops of the units, said bends at .the bottoms of said units having cleanout means associated therewith, and a frame tying said projections together whereby said units may be' lifted as a unit.

13. A heat exchanger having a pair of parallel header chambers in the lower part thereof a group of serpentine tubular units each having one end removably supported by and connected to receive fluid from one of said chambers and its other end supported by and connected to deliver fluid to the other of said chambers, said units each having a plurality of substantially vertical sections connected by return bends and unsupported except by the ends of the units, and means tying together the group of bends of each unit which lies the farther from said chambers.

14. A heat exchanger having a casing provided with an inlet passage and an outlet passage for one fluid, a pair of spaced headers near one end thereof having connections for a different fluid,

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