US2061980A - Heat exchanger - Google Patents

Description

Nov. 24, 1936; J. PRICE HEAT EXCHANGER Filed Dec. 10, 1931 2 Sheets-Sheet 1 INVENTOR ATTORNEYS Nov. 24, 1936. J, PRICE 2,061,980

' HEAT EXCHANGER Filed Dec. 10, 1931 I 2 Sheets$heet 2 INVENTOR Patented Nov. 24, 1936 UNITED STATES PATENT OFFICE HEAT EXCHANGER Delaware Application December 10, 1931, Serial No. 580,071

2 Claims. (Cl. 257-239) This invention relates to heat exchangers of the type in which a plurality of tubes are placed in a containing shell and which are commonly known as shell-and-tube or surface type heat 5 exchangers.

This type of heat exchanger is used principally in transferring heat between two liquids, such as in oil refining operations and'the like, and in transferring heat between a liquid and a gas as,

for example, in steam power plants and indus- I trial establishments. When used for transferring heat between two liquids, one liquid is passed through the shell of the exchanger and comes in contact with the outside surfaces of the tubes andthe other liquid is passed through the tubes, and the transfer of heat between the liquids takes place through the walls of the tubes.

the gas or vapor is usually passed into the shell and the liquid forced through the tubes.

Inthe particular form of shell-and-tube orsurface type of heat exchanger with which this invention is concerned, the tube bundle is secured at each end in a tube sheet and means are provided within the shell containingthe tube bundle .for conducting the fluid so that it makes two or more passes through the tube bundle before being discharged.

Inasmuch as the tubes are usually made of a 3 different metal then the shell and normally operate at a temperature different from that of the shell, the relative thermal expansion between the tubes and the shell must be compensated for. To this end, one end of the tube bundle is anchored at its tube sheet to the shell, while the other end of the tube bundle and its tube sheet is supported so as to allow it to move bodily within the shell in response to thermal expansion or contraction Also, the floating head is of a diameter sufficiently small to permit ready removal of the entire tube 50 bundle as a unit, including the tubes and both tube sheets, for purposes of repair and periodic cleaning, especially when oil and other viscous liquids are used therein. In order to effectively seal the connection be- 65 tween the floating tube sheetand the cap of the In trans ferring heat between a liquid and gas or vapor,

floating head, a very tight joint between them must be provided. It has been common practice heretofore to employ clamping devices which hold the cap and the floating tube sheet securely together and yet may be released readily to enable 5 the heat exchanger to be readily disassembled for cleaning and removing and replacing tubes and the like. These clamping devices usually include various kinds of so-called sectional rings to enable ready disassembling of the floating head and lo these have been found to be generally satisfactory, except that the sectional clamping rings have a tendency to cock, rotate, or cant about the inner periphery of the tube sheet, which they are intended to clamp squarely and securely to the 15 cap, when the clamping means, such as bolts, are tightened down.

It is the principal object of this invention to provide a heat exchanger in which the floating tube sheet is clamped securely and squarely to 20 the cap of the floating head without the use of sectional rings or other clamping means which are subject to misalignment caused by cooking or canting with respect to the floating tube sheet.

In accordance with this object, the heat exchanger includes a tube bundle having tube sheets at each end, one tube sheet being anchored to the shell in the usual way, and the other tube sheet being arranged to float in the shell to accommodate relative thermal expansion between the tubes and shell. The cap, into which one portion of the tubes discharges and which redirects the fluid into another portion of the tubes, engages with its rim the outer face of the floating tube sheet and the floating tube sheet is held against the cap rim in clamping relation by a plurality of separate spaced clamping elements anchored to the cap and having a head or other lateral extension or hook overlying the edge of the floating tube sheet for clamping it to the cap llm.

In this construction, the clamping members, when drawn tightly at spaced intervals over the edge of the floating tube sheet, secure the latter squarely and securely to the cap rim over a gasket, so that there is no tendency toward looseness or leakage. The clamping members may take various forms such as'hook-headed bolts, studs with separate heads of different shapes, and the like. The tube bundle including the floating tube sheet is of such dimension as to be readily removable as a unit from the shell for repairing and cleaning purposes.

For a better understanding of the invention,

\ reference is made to the accompanying drawings, in which Fig. 1 is a longitudinal section of a heat exchanger embodying the construction of the present invention;

Fig. 2 is an expanded view of the floating head consisting of the floating tube sheet, the cap, and the clamping members;

Figs. 3 and 4 are, respectively, a partial section and a partial face view of the edge of the floating head, showing the clamping members employed in the arrangement of Figs. 1 and 2, and

Figs. 5 to 14, inclusive, are views of modified forms of clamping members applied tothe floating head.

In these drawings, the heat exchanger includes the longitudinal cylindrical shell I having the inlet I I at one side and the outlet I2 at the opposite side, whereby a fluid such as steam, water, oil or the like, may be circulated through the shell. Supported within the shell II! is a tube btmdle I3 made up preferably of a relatively large number of small, thin-walled tubes. These tubes are expanded at the right-hand end into a fixed tube sheet I4 and at the left-hand end into a movable or floating tube sheet I5. In order to cause the liquid entering at the inlet II to pass longitudinally of the shell I0 and the tube bundle I3, a baille plate I6 extends from the fixed tube sheet I4 centrally'of the shell I0 and terminates at a point near the opposite end thereof.

The other fluid, such as oil for example, enters at the right hand end of the exchanger through the inlet I1, which delivers it to a chamber I8 from which it flows into the tubes of the tube bundle I3 lying on the upper side of the dividing partition I9. The liquid passing through these tubes is discharged into the floating chamber 20 at the left hand end of the exchanger, this chamber being formed between the cap 2| and the floating tube sheet I5, to which the cap 2| is secured in a manner to be described. This chamber redirects the fluid into the tubes of the lower portion of the tube bundle I3, whereby the liquid is returned to the right hand end of the exchanger and discharged into a chamber 22 on the lower side of the partition I9, from which it passes out of the outlet 23.

The shell I0 is provided at its right hand end with a connecting flange 24 and at its left hand end with a similar connecting flange 25. The fixed tube sheet I4 is clamped rigidly between the flange 24 and the castings 26 containing the inlet I1 and the outlet 23, by means of a plurality of long bolts 21. The shell In is closed at its lefthand end by means of a large dome-like cover 28, which is secured to connecting flange 25 by means of bolts 29. The liquid passing through the shell I0 is free to circulate within the dome-like cover 28 around the floating head of the tube bundle lustrated in Fig. 5, the bolt 4| formed by the cap 2| and the floating tube sheet |5.

This floating head is supported centrally in the dome-like cover 28 and the tube bundle I3 is supported centrally in the shell ID by means of an annular disc30 mounted on the tube bundle I3 near the left hand end of the exchanger. This disc has a large central opening for the free passage of the fluid in the'shell and is slidable axially in the shell III in response to the relative thermal expansion between the tube bundle I3 and the shell I0 and remaining stationary parts of the exchanger. tween the tube bundle I3 and the shell l0 and remaining stationary parts of the exchanger takes This relative thermal expansion besiderably. The floating tube sheet I is of slightly smaller diameter than the inside diameter of shell I, so that it can be withdrawn from the shell I0 when the tube bundle I3 is removed.

Cap 2| is provided with a thickened rim 3| having a plurality of holes 32 arranged in equally spaced relation around its periphery. The inner face of cap rim 3| is provided with the counterbore 33, shown especially in Figs. 2 and 3 and with the narrow lip or ridge 34 at its outer periphery. The floating tube sheet I5 is adapted to seat in the counterbore 33 of cap 2| over a sealing gasket 35, and the inner edge of the floating tube sheet I5 is provided with the recess-36.

As shown in Figs. 1 to 4, inclusive, studs 31, threaded at each end, are inserted through the peripheral holes 32 so that their inner ends project inwardly around the periphery of the floating tube sheet I5, when the latter is seated in the counterbore 33 of the cap 2|. The inner ends of these studs 31 are threaded into blocks 38, which have a lateral extension 39 overlying the edge of the floating tube sheet I5, as shown especially in Figs. 1 and 3, these extensions 39 of the block 38 being seated in the recess 35 of the floating tube sheet I5.

When the nuts 40 are tightened down on the studs 31 over the outer face of the cap rim 3|, the blocks 38 are drawn tightly against the inner face of the tube sheet I5 and against the peripheral lip or ridge 34 of the cap rim 3|. It will be seen that the ridge or lip 34 of the cap rim 3| holds the spaced blocks 38 against rocking or canting in a counter-clockwise direction about the periphery of the floating tube sheet l5, and that the extension 39 which overlaps the floating tube sheet I5 lies locked in the recess 36 thereof in such a way that any movement of the block 38 about the lip or ridge 34 as a fulcrum would only tend to clamp the tube sheet I5 more securely in the counterbore 33 of cap 2| and compress gasket 35 further.

Accordingly, by means of these spaced clamping members 38-39, which overlap the floating tube sheet I5 at spaced intervals around its periphery, the floating tube sheet I5 is clamped squarely and securely to the cap 2|. Also, simply by relieving these clamping members by loosening nuts 40, they may 'be rotated so as to with draw extension 39 from out of contact with floating tube sheet I5, whereby the floating head may be disassembled without actually removing the clamping members 3839. I

In the modification of the clamping means ilpasses through both the cap rim 3| and the clamping block' 42. The abutting surfaces of the cap rim 3| and the block 42 are made perfectly flat, but the inner face of the floating tube sheet I5 is provided with a radially inwardly sloping or tapered annular recess, into which the correspondingly shaped extension 43 on the block 42 fits closely. The gasket 44 is clamped between the outer face of the floating tube sheet l5 and the counterbore 45 in the cap rim 3| in which the floating tube sheet l5 lies. It will be seen that as the bolt 4| is tightened down, the tapered extension 43 is so shaped as to seat more tightly into the corresponding annular recess of floating tube lheet that just described in connection with Fig. 5, ex-

cept that the abutting faces 46 of the block 42 and the cap rim 3| are conical and dished together, so that when the-bolt 41 is tightened down, the block 42 is not only locked more selaterally extending head as of the T-bolt 49 jointly engages the lip 50 of the cap rim 3| and the inner face of the floating tube sheet I5. The gasket 5| lies between the cap rim 3| and the floating tube sheet l5. It will be seen that, as

the T-bolt 49 is tightened down, any tendency of the head 48 to rock takes'place about lip 50 of cap rim 3| as a fulcrum, so that the oppositeor inner end of the head 48 of the T-bolt 49 serves to force the floating tube sheet into more intimate contact with the gasket 5| and the cap rim 3|, whereby no rotating or canting of the T-bolts 49 can take. place in a counter-clockwise direction.

Fig. 8 is a face view illustrating the arrangement of the T-bolt in this construction.

Figs. 9 and 10 illustrate a bolt 52 having ahook head 53, which overlaps the inner face of the floating tube sheet I5, the lip 54 of the cap rim 3| preventing the, hook-headed bolt 52 from moving outwardly or canting away from the outer periphery of the floating tube sheet |5. With this arrangement, it is only necessary to remove or loosen the T-bolt 52 to release the cap 2| from the floating tube sheet 15, and the floating tube sheet and the cap 2| may be as readily assembled simply by inserting and tightening down the bolts 52. The gasket 55 between the floating tube sheet l5 and the cap rim 3| serves to seal the connection between them.

The modifications illustrated in Figs. 11 and 12 and in Figs. 13 and 14 are similar, in that the block 56 overlaps'both the lip 51 of the cap rim 3| and the outer face of the floating tube sheet l5, to hold the latter in place against the cap2| over the gasket 58; Instead of being passed entirely through the block 56, as is the bolt 59 in the arrangement of Figs. 11 and 12, the stud 60 is threaded through the block 56 and is tightannular recess thereof.

ened down on its opposite end by means of the nut 6|, in the arrangement illustrated by Figs. 13 A and 14. In each of these modifications, it is only necessary to release bolt 59 or the stud 60 to release the floating tube sheet Hi from the cap 2| and the cap 2| and floating tube sheet l5 may be as readily assembled by replacing and tightening down the blocks 56 by means of the corresponding bolts 59 or studs 60.

It will be seen that in each of the modifications of the floating head clamping means illustrated and described herein in connection with the invention, the usual sectional or split ring is eliminated and separate spaced clamping members are employed instead, and that these clamping members may take various forms, so long as they individually clamp the floating tube sheet to the cap rim and are so locked to the cap rim and floating tube sheet as to prevent'canting or cocking around the outer periphery of the tube sheet. In fact, in the various modifications of the inventionillustrated and described herein, the more these clamping members are tightened the less is their tendency to cant or rotate away from or about the periphery of the floating tube sheet. Also, in each case the clamping members may be readily removed separately or with the cap so that the, entire tube bundle including the floating tube sheet maybe withdrawn through the shell of the heat exchanger, the tube sheet being made of such diameter as to permit its withdrawal through the heat exchanger shell.

, Although the invention has been described in conection with a two-pass heat exchanger, it is to be understood that the invention is applicable with equal facility to a single pass heat exchanger or other apparatusrequiring a tightly sealed connection of this type.

I claim:

1. In a heat exchanger, the combination of a shell, a tube bundle therein, a tube sheet for one end of the tube bundle, a cap for said tube sheet having a rim engaging the outer face of the tube sheet, said cap rim having a conical seat in its inner face, and a clamping member having a tapered surface cooperating with the conical seat of the cap rim secured to the latter and overlapping the inner face of the tube sheet.

2. In a heat exchanger, the combination of a shell, .a tube bundle therein, a tube sheet for one end of the tube bundle, a cap for said tube sheet having arim engaging the outer face of the tube sheet, said cap rim having a conical seat in its inner face and said tube sheet having a tapered annular recess in its inner face, and a clamping member having a tapered surface cooperating with the conical cap rim seat and a tapered extension overlapping the inner face of the tube sheet and cooperating with the tapered JOSEPH PRICE.

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