US2988335A - Heat exchangers - Google Patents

Description

F. A. DISINGER Erm. 2,988,335

HEAT EXCHANGERS June 13, 1961 2 Sheets-Sheet 1 Filed March 6, 1958 Pff unnmmnmmn r .iinmF-H* um AVAVAVAVAVA'A'AVA'A'AVAVAVAVAVAVAVAVAVl"r "uw f June 13, 1961 F. A. DlslNGER ETAL 2,988,335

HEAT EXCHANGERS Filed March 6, 1958 2 Sheets-Sheet 2 A 7' TORNEY United States Patent() 2,988,335 i HEAT EXCHANGERS Frank A. Disinger, Lockport, and Vincenzo A. Nicola,

Middleport, N.Y., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware `Filed Mar. 6, 1958, Ser. No. 719,639 2 Claims. (Cl. 257-236) This invention relates to `heat exchangers and more particularly to heat exchangers in which differential expansion of the metal parts is a problem due to special uses or high temperatures to which the exchangers are subjected in conveying heat from one fluid to another.

In many uses such as transferring heat from liquid metal to air, for example, a problem has arisen to provide ample surfaces for counterflow heat exchange between the two fluids and, at the same time, to avoid any undue variation in temperatures of the exchanger parts which would cause failures of those parts.` `If the exchanger casing and tubes are not such as to accommodate themselves as fully as possible to the expansion obtaining, metal fatigue will appear in localized and vital areas. If the heat exchange surfaces are increased by the expedient of using smaller tubes, the danger of tube blockage increases and such an increase, in turn, gives rise to a more adverse situation insofar as any unbalanced expansion problem existing is concerned.

An object of the present invention is to provide an improved heat exchanger minimizing the adverse effects or stresses set up in the heat exchanger structure because of temperature differentials. Another object is to provide a heat exchanger suitable for metal to air service under counterflow conditions and in which eifective heat transfer areas are large in extent and in which small ow passages are avoided.

A feature of the present invention is a heat exchanger utilizing tubes and having a casing enclosing the tubes and being characterized by peripheral slots therein to accommodate liuid llow, the slots lying in planes transverse to the tubes. Another feature is a heat exchanger with a casing substantially divided but not severed into portions by peripheral slots formed in the casing, the adjacent portions of the casing being connected by an intake or diaphragm manifold capable of functioning as such enclosing the slots.

These and other important features of the invention Will now be described in detail in the specification and then pointed out more particularly in the appended claims.

In the drawings:

FIG. 1 is a sectional view through a heat exchanger with arrows depicting the counterflow paths of fluids;

FIG. 2 is a sectional View looking in the direction of the arrows 2-2 in FIG. l showing a portion of the heat exchanger and drawn to an enlarged scale;

FIG. 3 is a sectional view looking in the direction of the arrows 3-3 in FIG. l; and

FIG. 4 is a sectional view looking in the direction of the arrows 4-4 in FIG. l.

In the drawings, a heat exchanger is depicted having a casing generally indicated at 10. This casing is cylindrical and comprises an intermediate portion 12 which is integral with two end portions 14 and 16. IThe portion 14 bears a flange 18 by means of which it may be connected to a source of supply for air. The end portion 16 is provided with an end ange 20 which may be connected to a device for receiving air which has been heated in passing through the casing 10.

The end portion 14 is connected to the intermediate portion 12 by means of casing sections 22 and 24. These sections are clearly seen in FIGS. 3 and 4. It will be noted that the sections 22 lie in one plane transverse ice to tubes 26 arranged within the casing 10 and that these sections serve to separate peripheral slots 28 and 30 which are formed in the casing Iand in that same transverse plane. The sections 24 separate two additional slots 32 and 34 formed in the casing. The sections 22 also may be said to lie in a horizontal plane whereas the sections 24 lie in a vertical plane, and these planes extend parallel with the tube lengths. It will also be noted that the slots 28 and 30 lie in a plane parallel with the plane in which the slots 32 and 34 `lie and that the sections 22 are oifset an angle of 90 `from the sections 24 as considered in the direction of the casing axis.

An annular manifold 38 is provided in. the form of an inwardly directed trough and it surrounds the casing 10 and joins the end portion 14 to the intermediate portion 12 thereby enclosing the slots 28, 30, 32 and 34. The manifold is joined to the intermediate portion 12 by welding as at 40 and to the end portion 14 as at 42. One end of a discharge conduit 44 is joined to the manifold 38 by welding as at 46 and communicates with the manifold.

The intermediate portion 12 of the casing is joined to the end portion 16 by four olfset casing sections as determined by slots, these sections Ibeing similar to the sections 22 and 24. Ioinder to the portion 12 is also by an annular manifold 48 constructed in the same manner as the manifold 38. The manifold 48 is provided with an inlet conduit 50.

A circular tube sheet 51 is joined at its periphery to the end portion 14 of the casing as by welding shown at 52. A similar tube sheet 54 is joined in a similar manner to the end portion 16 of the casing. Communication is had between the two end portions 14 and 16 through the intermediate portion 12 by means of the tubes 26, the ends of which are xed to the tube sheets by conventional methods to form uid tight joints.

As seen in FIGS. 3 and 4, each tube is of elongated cross section thus forming a relatively large uid passageway through the full length of the tube, and in order to increase the heat capacity of the heat exchanger, each tube is fitted with an internal iin 60 of thin corrugated metal which extends the full length and width of that tube. Preferably, but not necessarily, the corrugations in the ns are made to extend lengthwise of the tubes as shown in the drawings. Such tins could be slotted and take any of various forms suitable for transferring heat.

In operation of the heat exchanger, liqjuid metal ows from the conduit 50 into the manifold 48. Prom this manifold it enters the chamber or intermediate portion 12 of the casing by way of the slots enclosed by that manifold. This liquid metal circulates around the tubes 26 and flows to the left, as viewed in FIG. l, for discharge from the heat exchanger by Way of the slots 28, 30, 32 and 34 to the manifold 38 and from thence by way of the discharge conduit 44.

Air entering the casing end portion 14 at the left-hand opening thereof, -as viewed in FIG. l, passes through the tubes 26 in contact with the fins 60 and is discharged by way of the opening formed by the end portion 16. The counterow passage of the molten metal and air along the lengths of the tubes 26 effects efficient heat exchange. For convenience, the lair may be termed a first iluid and the molten metal may be called the second fluid.

It is obvious from the above description that the physical integrity of the casing 10 is maintained by the casing sections separating or determined by the slots; and, despite such integrity, ample provision is provided for minimizing the expansion problems due to possible temperature variations in the casing and tubes.

It is also to be noted that the passages between the tubes 26 are of such large cross section that any partial or localized blockage by molten metal is not probable and, therefore, the possibility of undue temperature diierentials in the metal parts of the exchanger is minimized. Since the casing 10 is not completely severed into portions as is usually true when providing an expansion joint, fabrication of the exchanger is simplilied because additional xtures lare not required Vto assure proper alignment of parts. With the use of two manifolds 38 and 48, las depicted, each manifold may be relied upon to absorb one-half of the differential expansion involved and it also supplies the means for 360 liquid metal distribution to the core or discharge from the core.

We claim:

1. A heat exchanger comprising a tubular casing having -inlet and outlet openings at each end for conducting a lirst lfluid, axially spaced transverse tube sheets in the casing defining together with a portion of the casing a chamber for a second uid, tubes supported by said -tube sheets and extending through said chamber for conducting the first iluid between said openings, peripheral slots defining llow passages for the second fluid formed in the casing wall at each end of said chamber, said slots being arranged in multiple parallel planes transverse to said tubes and separated in each of said parallel planes by remaining casing wall sections, the said sections in said planes being relatively offset in the direction of the casing axis, a manifold in the nature of an expansion joint at each end of said chamber simultaneously serving as a conduit for the second fluid joined to the casing and straddling the slots to provide communication therewith and said chamber and an inlet port for the second lluid in one manifold and an outlet port therefor in the other.

2. A heat exchanger comprising means for accommodating ow of a first duid in heat exchange relation with a second uid, said means including a casing having van intermediate portion and two end portions including inlet and outlet for conducting said rst fluid, said portions being joined by casing sections separated by peripheral slots formed through the wall of said casing in at least two planes transverse to the casing axis, a transverse tube sheet in each of said end portions, tubes .extending -through said intermediate portion and supported by 4said tube sheets for conducting the `lirst Huid, the casing sections joining each of said end portions to said intermediate portion being offset in the direction of the axis of the casing, said intermediate portion with said slots as ow passages serving to conduct the second fluid, a manifold in the nature of an expansion joint joining each end portion to said `intermediate portion, each of said manifolds straddling the respective slots -to form a uid passage around said casing in communication with the slots and intermediate portion and an inlet port for the Vsecond lluid in one manifold and an outlet port therefor in the other.

References Cited in the iile of this patent UNITED STATES PATENTS Germany Oct. 1,3, 1952

Images