US2256882A

US2256882A - Heat exchanger

Info

Publication number: US2256882A
Application number: US261256A
Authority: US
Inventors: Leslie E Sebald
Original assignee: Griscom Russell Co
Current assignee: Griscom Russell Co
Priority date: 1939-03-11
Filing date: 1939-03-11
Publication date: 1941-09-23
Anticipated expiration: 1958-09-23

Description

Sept.*23, 1941. L. E. sEBALD A HEAT EXCHANGER 3 Sheets-Sheet 2 Filed March -11,` 1939 EYE I lNvENToR` ,Q TSM BY @mi bmxm I ATToRN Sept 23, 1941- E. SEBALD HEAT EXCHANGER 3 Sheets-Sheet 3 Filed March ll, 1939 f Y INVENTOR SM W ATTORNEYS I Peienie'd sepf.' 23, 1941 HEAT EXCHANGER Leslie E. Sebald, Ridgewood, N. J., assignor'to The Griscom-Russell Company, New York, N.' Y., a corporation of Delaware Application March 11, 1939,*ser'ia1No. 261,256

i 6 Claims.

'Ihis invention relates to heat exchangers of the shell and tube type now extensively used as evaporators, condensers, water heaters, etc'., in

differences in temperature which necessarily exlst in different parts of the apparatus, and one object of the present invention is to provide a structure wherein the expansion of different parts of the apparatus to different degrees ,may take place with a minimum of strain upon the joints and other parts subject to breakage and leakage. l

In apparatus of this kind, particularly when used for liquids and vapors containing corrosive impurities, frequent replacement of the heating tubes is necessary, and a second object of the invention is to provide a structure wherein the removal and replacement of the worn out tubes is greatly facilitated.

` A further object of the invention is to provide a structure which is of Ycompact design and dimensions, and in which a high rate of heat exchange per unit of heating surface is obtained.

In the accompanying drawings VI have illustrated in detail certain embodiments of my invention which are now in commercial use.

In said drawings:

Fig. 1 shows in vertical longitudinal section an evaporator embodying my invention;

Fig. 2 is a transverse section on line 2 2 of Fig. 1 on a somewhat larger scale;

Figs. 3 and 4 are detail views of certain parts 'of the` apparatus which will be later described;

Fig. 5 shows in vertical section a water heater embodying my improvementa y Referring to the drawings, l indicates the shel of the apparatus, here shown as an elongated horizontal cylindrical shell designed to contain two heating units or tube bundles 2 and 2a resembled on a single freight car, whereas shorter shells of greater diameter have to be made and shipped in sections. A heat exchanger which may be shipped assembled can be thoroughly tested before shipment and its performance assured, whereas apparatus which has to be erected at the 'place of installation ls subject to defects in erection which are difllcult to remedy.

`One end 3 ofV the shell is preferably welded permanently to the shell body, whereas the other end 3a is bolted by a double series of staybolts (see Fig. 4) tothe flange 5 formed integral with orwelded permanently to the shell body. .Any

type of joint may of course be employed between the head and the body of the shell, but I prefer to usel the joint illustrated for the reason that it will withstand high internal pressure without leakage. As shown, the cover 3a is provided with a heavy flange 6 which is set back from its edge. .A second liange or ring l of much lighter weight is welded, as shown more particularly in Fig. 4to the edge of the open side of the cover, this ring y-'l -being shaped to form a huid-tight joint with the face of the flange 5. The -ring 1 iswelded at its inner edge only to the corresponding edge of the end cover 3a to thereby permit a limited relative movement of the end cover and the shell body I without disturbing the joint between the flange 5 and ring 1.

The joint between the ange 5 and ring 1 is maintained fluid--tight by one of the two series of bolts above referred to, namely, the smaller spectively. As shown, the tube bundles 2 and laV are composed of U-shaped tubes arranged 'so that the planes common to the axes of the two legs 4oi the tubes are vertical and parallel.

The elongated horizontal shell illustrated has the advantage of large capacity in proportion bolts 8 which terminate in the space between the ring 'l and ilange 6. The other larger andv heavier bolts 9 extend freely through holes in the r'ing 1, then through the heavy flange' 6 on the end cover, against the outer face of which the nuts on the ends of the bolts are drawn.` By thisv construction the internal pressure on the end cover 3a places no strain on the bolts 8 which maintain the joint between the ring 1 and ilange 5 fluid-tight. Instead the pressure on the end cover 4 is met entirely by the bolts 9 which are heavy enough to withstandthe pressure without elongation beyond their elastic limit. Thiselongation of the bolts 9 does not tend to open the joint between the end cover and the shell as it is less than the movement permitted by the flexible joint between the ring 'l andthe flange 6.

One of the principal features of my invention is the provision of a header made in separate upper and

lower parts

4 and 4a, respectively. Inv

.the part 4 the upper ends of the tubes are expanded, while the ends of the lower portions of the tubes are expanded in the lower header section 4a. The purpose and advantages of this divided head structure will be later pointed out.

The tube bundle is supported in the shell by rollers I (see Fig. 2) mounted for rotation in brackets II attached to the bottomedge of the header section 4a, said wheels resting, as shown in Fig. 4, on rails I2 extending the length of the shell. Additional rollers I3 are provided for supporting the looped end of the tubes, these rollers being attached as shown to the lower corners of tube-supporting plates I4 provided with holes for the tubes.

Each tube-supporting plate I4 is connected to .its

header sections

4 and 4a by means of longitudinal angles 25, six of which are preferably provided, as shown in'Fig. 2. Also attached to the ment breaker or steam separator I1. Separate steam -outlets for the two tube bundles are provided at I8 and I9, respectively. The supporting plates may with advantage be made in two sections bolted together in the same way as the two headers.

The two upp'er header sections are supported within the shell by means of connections 21 connected to the source of steam supply when the apparatus is used Vas an evaporator, and hangers I4a, while the lower header sections are attached to centrally located connections I for the discharge of the condensate in the tubes. The steam and ,drain connections extend through the top and bottom of the shell, respectively, in the same transverse vertical plane as the headers, and one advantage of the divided header construction is to permit the ready removal of the tube bundle from between these connections.

In removing the tube bundles the end cover 3a is removed and the joint between the lower connection and the lower header is then broken by the removal of the bolts. The lower header is then elevated by tightening thejack screws to a suicent extent to permit tapered channel members 50 (see Fig. 3) which lt over the tracks in the shell to be pushed under the supporting wheels I0. The bolts are now taken out of the joint between the connection 21 and the upper header and one of the pins is removed from the hanger I4a. The upper header will thereupon sink of its own weight until it rests on the lowerV header section, thereby breaking the joint between this connection and the upper header. The

' tube bundle is now free to be rolled out of the shell on the tracks I2. After the tube bundle 2 is removed the tube bundle 2a .may be similarly removed.

During the removal of the tube bundle 2a the channels 50 previously placed under the supporting'l rollers of the tube bundle 2 will beV left in place and similar `channel sections used for supporting the header of the tube bundle 2a, so that along the tubes toward the headers a sufficient distance to permit the outer tubes in the row containing the defective tube to be deflected sunlciently to get holdof the defective tube and withdraw it from the bundle. Thev legs of the tubes are not exactly parallel but are inclined slightly for drainage. Hence-the tube supports I4 and 26 cannot be moved longitudinally of the tubes as a whole, but by making the tube-supporting plates in sections, as shown, the splice plates which connect the sections may be loosened, permitting the upper and lower sections of each plate to be shifted separately. The degree of inclination of the tubes is too slight to be illustrated in the drawings of the apparatus as a whole and as this feature is not claimed in this application, no detail view is included.

After the defective tubes are replaced the tube bundle may be replaced in the shell by reversing as the tube bundle 2a is shifted along the tracks y,

it will be elevated as its headers pass over the drain connection of the tube bundle 2.

After the tube bundle is rempved the replacement `of va defective tube, no matter where it may be located in the tube bundle, vcan be accomplished without removing any of the other tubes. To this end the tube-supporting plates I4 and 26 are disconnected from the angles 25 and shifted the procedure followed in removing the bundle. The channel-shaped lifters on the tracks will lift the headers to clear the lower connections. as the tube bundle is returned to position. The jackbolts will be screwed down to draw the two header sections together, and after the bundle is in position the steam inlet connection will iirst'be made, the effect of which is to lift the headers slightly, thereby removing their weight from the channels. The channels are then removed from the tracks, and the jackbolts loosened to allow the lower header to drop downl into position to tighten the lower connection.

Making the headers in separate upper and -lower sections also serves to greatly reduce the strains which otherwise would result from .expansion. In many fields of use of heat exchangers of this type there is a wide temperature difference between the upper and lower sections of the to the under side of the shell and provided with.

bearing lfaces 22 resting on rollers 23 which in turn are maintained in positcn between the bearing 2I and the floor plates 24. The shell may thus freely expand at both ends without distortion to the full extent permitted by the steam and drain connections. s

In Fig. 5 I have illustrated my improved heat exchange structure adapted for use in a high temperature-high pressure water heater. As will be observed, the structure is the same as the evaporator construction above described, except that the entrainment separator and plate balde employed in the evaporator structure are not required in a Water heater and these parts are' Ytherefore omitted, permitting the use of a larger tube bundle in the same diameter shell.

For convenience the water heater is shown as having but a single tube bundle, but it will of heater.

In the water heater selected for illustration the water to be 'heated is admitted to the tubes Near the ends of the shell are addithrough the connection to the bottom header section as indicated on the drawing, thence passes through the tubes tothe upper header section which is connected to the Water discharge outlet. The heating steam which is at high temperature is. admitted to the shell through the steam inlet in the top wall of the shell abovethe tubes, and is condensed on the tubes, thereby heating the water in the tubes. The condensate is drawn olii through the cohdensate outlet. The unit described is designed for operating pressures in excess of `2000 pounds per square inch. These conditions of high temperature andhigh pressure expansion strains are very apt to result in breakdowns and leakage. In the design illustrated such strains are reduced to al-minimum.

As previously stated, the apparatus disclosed in this application is particularly suited for high temperature-high pressure operating conditions.

In the preferred embodiment of my invention above described'I have disclosed 'U-tubes which have been found economical and practical, but it will be understood that'the invention is not limited to U-tubes as the various novel features of construction may be employed with advantage with straight tubes orbowed tubes having headers at both ends. It will also be understood that various other changes may be made in theconstruction disclosed without departing from the scope ofthe invention as dened in the appended claims.

I claim:

vof the track surface shell, a horizontal tube bundle therein, means comprising a track for supporting said tube bundle, a fluid connection at the bottom of said tube bundle, and a movable track section adapted to be mounted on the track for altering the height adjacent said fluid connection.

4. In a heat exchanger, the combination of a horizontal shell, a removable cover at one end thereof, supporting tracks extending the length of said shell, a plurality of separate removable tube bundles supported in said shell on said tracks, separate inlet and outlet connections for said tube bundles each of said inlet and olutletl connections comprising a fixed portion attached to the, shell and a portion on the tube bundle movable therewith and positioned to register with the xed portion when the-tube bundle is in proper position in the shell, the fixed portions for the tube bundleadjacent the removable end cover being disposed out of the path of movement of the removable tube bundles in their movement out ofthe shell.

1. In a heat exchanger, the combination of a A shell, a horizontal tube bundle supported in the shell, a header at one end of the tube bundle, said mounted one above the other in the same verti- A c'al plane, inlet and outlet connections for said headerbeing constructed of two relatively movable sections, said header sections being in the same vertical plane, inlet and outlet connections for said header, said connections extending upwardly and downwardly in the plane of the header sections, means for adjusting said sections toward and away from said connections in said common plane, supporting means for said headers adjacent the connection to the lower header section and means for altering the height at 2. In a heat exchanger, the combination of a shell, a horizontal tube bundle comprising tubes and headers therein, supporting means within said shell for saidtube bundle, a fluid connection at the bottom-of said tube bundle, and means for altering the height at which said headers are supported withinsaid shell adjacent said fluid connection.

3. h1 a. heat exchanger, the combination of a plane.

40 ,x 6. In a heat exchanger, the combination of a header, said connections -extending opposite from each other in the plane'of the header sections,

and means 'for adjusting said headers toward and away from said shell, a horizontal tube bundle supported in the shell comprising a plurality of tubes having inow and return portions arranged respectively in parallel, separate headers for the inflow and rewhich said headers'are supported adjacent said connection.

turn portions, each header comprising a substantially vertical tube sheet with the ends of the tubes tted therein and cover sections enclosing the open ends of the tubes, said headers being mounted one above the other in the same vertical plane, inlet and outlet connections for said header, said'connections extending opposite from each other in the planeof the header sections, and bolt means connecting said headers for drawing said headers towards one another.

connections 'in said commonA