US2003758A - Heat exchanger - Google Patents

Description

E. PICK HEAT EXCHANGER June 4, 1935.

Filed Sept. 21, 1934 3 Sheets-Sheet 1 E. PICK HEAT EXCHANGER Filed Sept. 21, 1934 June 4, 1935.

3 Sheets-Sheet 2 m men E. PICK HEAT EXCHANGER June 4, 1935.

Filed Sept. 21, 1934 3 Sheets-Sheet 3 Patented June 4, 1935 HEAT EXCHANGER Eric Pick, New .York,

Permutit Company, (1934), Wilmington, DeL, a corporation of Delaware Application September 21, 1934, Serial No. 744,972

' 14 Claims.

This invention relates to heat exchangers; and it comprises an improved heat exchange apparatus having a plurality ofmembers closed on one face and provided with open channels on the 5 other face, the members being assembled into a unit with the open faces juxtaposed, the unitary assemblage having a plurality of separate, tortuous, immediately adjacent passageways for fluids, the open channels of 'each'member being so arranged as to form parts of the fluid passageways in the assembled unit, the apparatus having ported separator means between the members for establishing" passageway connections between members, the' apparatus having conduit connections for each set of passageways and means for holding the members together; all as more fully hereinafter set forth and as claimed.

Heat exchange apparatus in general comprises means for bringing two fluids (gas or liquid) into intimate heat transferring relationship, as by providing flow conduits separated by a thin wall of metal such as iron, copper and its alloys or aluminum. For efficient heat exchange, the area of heat exchanging relationship (through the dividing wall) for the two fluids should be large.

In conventionalheat exchange design, at least one of the conduits for the two fluids is tubular piping. Sometimes concentric pipes are provided, forming two conduits; sometimes two pipes are laid closely adjacent and usually arranged in coils to save space; and sometimes a coil or nest of pipe containing one fluid isimmersed in a surrounding body of the other fluid. In these conventional designs, it is not desirable to have the cross-sectional area of the conduit large, be-

cause in this casethe-flow of liquid, for example, through the conduit under ordinary pressures is stream-line and the central portions of the flowing stream do not come into contact with the conduit walls. Unless liquid actually comes into contact with the conduit walls, heat exchange is in general impossible, Most liquids are poor heat conductors. Moreover,.in stream-line flow conditions the rate of flow through the conduit is greatest in the center and diminishes to a low value adjacent the walls. In effect, thin fllms conduit, the greater the pressure required to N. Y., assignor to The REISSUED' force liquid therethrough. This sets a practical limit for the conduit size. Conventional type heat exchangers with large conduits are ineflicient thermally. With small conduits they are ineflicient mechanically; pressure losses for a 5 given volume flow rate are high.

Whatever the arrangement, in operation it is usual to flow the two fluids in countercurrent through the apparatus.

The ordinary heat exchange apparatus of tubular construction is low in efliciency and moreover is diflicult to construct. The many pipe" joints give opportunity for leakage to occur, particularly under high pressures. Attempts have been made to-improve upon conventional con- 5' struction. It has been proposed to cast the conduits for fluid flows in a unitary block. Such proposals are, however, diflicult to embody in practice, because of the obstacles in the way of producing a single casting containing winding fluid channels enclosed therein. It has been further proposed to make up a heat exchanger of a-large number of small discoid segments, eachhaving portions of spiral passageways for two liquids; but such arrangements require almost as many joints as ordinary tubular apparatus, and in addition they have many of the disadvantages of cylindrical conduit systems. Flow through a simple helical passage tends to be streamline unless high velocities, with resulting high pressure losses, are used.

According to the present invention, I provide an improved heat exchange apparatus made up usually of two unitary elements, each element having open channels or grooves on one side and being closed or encased on the other side, the channels being so disposed that when the elements are assembled the outer faces provide a solid casing, while on the inside two separate, adjacent, winding passageways are provided ex- 40 tending through the assembly and separated by thin walls. Ported separator means are interposed between the elements to make interchannel connections between. elements. Fluid. connec-' tions are provided at the extremities of the passages. Each element is of open shape readily formed by simple casting methods. The new heat exchanger is cheap to build and furthermore is highly efiicient; much more so than any of the prior designs mentioned. The channels, while of large cross-section, are so arranged that the flow of fluid therethrough is turbulent even at low pressures. Streamline flow, with forma-' tion of hot or cold centers in the flow, is prevented. At the same time, fluid resistance is kept low; the cross-sectional area of the passages is large. The apparatus can be readily assembled and disassembled for cleaning purposes.v

In the accompanying drawings Ihave shown, more or less diagrammatically, several specific embodiments of apparatus within the invention.

In the showings,

Fig. 1 is a view in elevation of one embodiment of the invention;

Fig. 2 is a plan view of the .top member of Fig. 1;

Fig. 3 is a view partly in elevation and partly in vertical section of the member of Fig. 2;

Fig. 4 is a plan view of the separator plate used in the embodiment of Fig. 1;

Fig. 5 is a cross-sectional view taken along line 55 of Fig. 1;

Fig. 6 is a plan view of a'modified form of heat exchanger, one cover member being left oif in this figure;

Fig. 7 is a cross-section of the apparatus taken along line 'i--l of Fig. 6 and showing both cover members;

Fig. 8 is a plan View of a cover member of the apparatus of Fig. 6

Fig. 9 is a perspective view of one end of the separator member in the apparatus of Fig. 6, showing the flow channel arrangement in the separator member;

Fig. 10 is a view partly in elevation and partly in vertical section of another specific embodiment of the invention;

Fig. 11 is a plan view of the top member of the apparatus of Fig. 10;

Fig. 12 is a plan view of the bottom member;

Fig. 13 is an end View of the apparatus of Fig. 10;

Fig. 14 is a plan view of the gasket used with this embodiment, and

Fig. 15 is a sectional view taken along line I5l5 of Fig. 10 and showing the course of fluids through the apparatus of Figs. 10 to 14.

The heat exchanger shown in Figs. 1 to 5 comprises a top channeled member 20 and bottom channeled member 29, the two members being bolted together by a plurality of tie-bolts '22 with nuts 23; a port plate 2 3 and two gaskets 25 being interposed between the two members. In this modification, the two members are alike except that the top member is formed with two bosses 26 at each end having bores 2'! there: through adapted to receive the ends of fluid conduits indicated at 30, the bores in most cases being threaded to receive ordinary threaded pipe. The top channeled member is shown in plan in Fig. 2 and in section in Figs. 3 and 5. As shown, the-member 20 has an outer casing portion 39 of general cylindrical contour and a plurality of partitions 32 of roughly semi-circular shape integral with the casing and forming a plurality of open cavities or channels 33 in the member side by side. The channels or cavities are so arranged that each end of one channel in one member overlaps one end of one of two channels in the other member, the two channels being spaced apart and separated by a third channel in the other member. A low rib 34 extends along the length of the member. The purpose of this rib is to give additional structural strength and to promote turbulence in the fluid flow through the channels. A plurality of round holes 35 are provided around the periphery of the member to receive the tie-bolts 22. The lower member U is similar in channel arrangement to the upper member. The only difierence between the two members is the provision of the conduit connection bosses 26 on the upper member alone. Usually the members are cast. The same pattern can be used for each, the casting pattern being provided with removable pieces corresponding to bosses 26 which are left'in when the upper member is cast and removed when the lower member is cast. Bores 27 can be provided during the casting, or the bosses can be left solid and drilled out afterwards. If desired, both members can be cast with bosses, the members in this case being exactly alike; and only one set of bosses drilled out subsequently.

In this embodiment, a rigid separator plate between the two members is required to properly connect the channels of the two members so as to provide in the apparatus two separate winding channels leading from one end of the apparatus to the other. The separator plate 2 is shown in Fig. 4. It is a thin metal plate with a plurality of fluid bores i0 therein and holes 35 for the tiebolts. When the two channeled members are bolted together with the separator plate between them, two separate spiraling win-ding passages are formed in the assembly. The bores it serve to establish communication between overlapping ends of channels in the two members. Usually it is desirable toemploy a gasket between the separator plate and each member, as shown in Fig. 1. The gasket is exactly the same size and of the same bore arrangement as the separator plate and is made of material appropriate to the conditions under which the heat exchanger is used. The gasket is made of material adapted to withstand the operating temperatures to which the apparatus is subjected, and to Withstand corrosive action of the fluids. Various composition materials are suitable, the compositions sometimes being reinforced by a metal cloth insertion. Lead or soft copper is sometimes employed.

Figs. 6 to 9 show a modified form of heat exchanger wherein the separator member is of greater thickness than in the first described modiflcation and also contains the fluid conduit connections. The apparatus comprises two channeled cover members 45, exactly alike and of general semi-circular longitudinal cross-section. Each cover member comprises a casing portion 46 having a partition system 52 comprising partitions 53 disposed therein so as to form a plurality of channels 41 and 48. In this specific embodiment the passages for the two fiuids are shown as of different cross-sectional area. The passage of which channels 48 form a part is smaller than that formed by channels Lil. The channels or cavities are so arranged that each end of one channel in one cover member is opposed to one end of one of two channels in the other cover member. The cover member is shown as having perforations 49 for receiving the shanks of tie-bolts 22. Fig. 6 shows a separator member 50 superposed on one cover member, the other cover member being left Off in this view for clarity. As shown, the separator member has'"a casing portion 5| of general rectangular shape. A branching open-faced partition system 52 is provided in the casing and integral with the casing. This arrangement is shown most clearly in Fig. 9, which is a perspective view of one end of the separator member. The partition system comprisesadjacent partition members 53 enclosing therebetween openfaced channels 48 and branched as at 55. Upon the faces of the separator being closed by the cover members the closed channels 48 extend continuously from one end of the apparatus to the other, while inter-partition channels 41 are provided, forming a closed continuous channel extending from one end of the apparatus to the other, The channels and inter-partition spaces of the separator member establish communication between opposing channel ends in the two cover members. At each end of the separator member are two connection bosses, 55 and 55, for the two fluids. Theconnections are of different size. Connection 55 is in communication with the smaller passageway formed of channels 48; connection 56 delivers to the larger passageway formedv of channels 41. The separator member has indentations 51 for receiving the bolt shanki, corresponding to perforation 49 in' the cover members. The fluid connections 55 and 55 are shown as being flanged as at 58. This construction is desirable as it allows any number of heat exchanger units to be readily bolted together in case larger heat exchange capacity is required than that afiorded by a single unit. When the two cover members and the separator are bolted together, appropriate gaskets being provided as at 59, the two separate winding fluid channels are formed in the apparatus in a way similar to the first described embodiment. The quasi-ellipitical cross-sectional shape of the apparatus as is shown in Fig. 7 is a desirable one as it promotes turbulence of the fluid flows better than a purely circular cross-section (helical passages). The course of liquids throughthis apparatus is indicated in Fig. 6 as at 60 for the larger flow and as at lilfor the smaller flow. A threaded socket 62 is advantageously provided in the separator member 50, to receive an eyebolt (not shown) or the like for handling the apparatus.

The exchanger of Figs. 6 to 9 is a remarkably eflicient apparatus. In case extreme simplicity is desired rather than fnaximum efliciency, cover members 45 can take the form of flat-surfaced plates.

Figs. 10 to 15 show a third modification in which.

the channel arrangement is such that use of a id separator plate is. obviated. In this modification the upper and lower channeled members are similar, but are not exactly alike. Fig. 10 shows the assembled unit having a channeled top member 10 and a "channeled bottom member ll, each member being flanged as at 12. The flanges are provided with a plurality of holes 35 for tie- ,bolts as shown. The two channeled members are tied together with a plurality of bolts and nuts 22.

23 as in the previously described embodiments. The top member is provided at each end with two fluid connection extensions 13 and I4 receiving'a.

larger conduit 3|) and a smaller conduit 30, respectively. These extensions are advantageously threaded to receive the usual threaded pipe connections or they may be provided with flanges or other convenient connection means. Fig. 11 is a plan view of the top member which is shown as having a casing 15 of general rectangular form and integral with flanges l2 and an integral, single, looped partition 16 extending from one end of the member to the other. This specific embodiment is shown as having different sized passages. The loop is so proportioned that series of smaller channels 48' and larger channels 49' are formed in the member. Partitions are provided between the looped partition and the walls, as shown, forming a plurality of open, separate cavities in the member. A rib 34 is provided in the top of the casing as in the first described embodiment. for assisting and promoting turbulent flow. The channeled member has orifices BI and 82 at each end leading to the fluid connections I3 and I4, respectively. Ribs 83 are provided on the casing walls to aid in promoting turbulence. 1

The lower channeled member, shown in plan in Fig. '12, hasa similar partition arrangement, including looped partition 15 and partitions 80, forming with the partition IS a plurality of open, separate cavities in the member and is generally similar to the top member except for the omission of the fluid connections. The two members when bolted together, as shown in Figs. 10 and 13, are adapted to form two separate tortuous passageways or channels extending from one end of the casing to the other end. Each end of any one cavity in one member overlaps one end of two-cavities in the other member, the two cavities being spaced apart and separated by the end of a third cavity in the other member. For example, a U-shaped cavity in member ll has ends 9| and 92. Upon assembly the end 9| overlaps the end 80 of one cavity in member ID, and the end 92 overlaps the end 94 of another cavity in member III. A third cavity ending at 93 in member 10 is located between the two cavities ending at 90 and sl-(Fig. 11).

Thev ported separator means in this modification need not be a rigid plate; it can be a simple .gasket. The apparatus is so designed that no vertical pressures are exerted on unsupported portions of the gasket area, so that the gasket need be adapted only to withstand lateral pressures as in ordinary gasket practice. Fig. 14

shows a gasket as used in this modification.

air expelled from the water being warmed and tending to become trapped in member H (which has no direct liquid connection), to escape into the other member, whence it is discharged with outgoing water. For most other uses the air bleeds are not provided.

The channeled members and the gasket are assembled in such manner that reference points A in each element are-superposed. The course of fluids through the apparatus is shown diagrammatically in Fig. 15, which is a diagrammatic plan sectional view of, the apparatus taken along line [5-45 of Fig. 10. The course of the larger flow is indicated by line 60; that of the smaller flow by line 6|.

.The new heat exchange apparatus comprises few parts, is easy to construct and is reliable in use. In the first two modifications described, three metal members only are required: two similar open castings and one flat ported member. In making up the heat exchange apparatus only four surfaces need be tooled or machined: the open faces of the cover members and the two faces of the separator plate. With certain types ble to cast the channeled members with the partition walls very thin; thereby securing efiicient heat transfer. The apparatus of Figs. 10 I to 15 is made up of but two channeled parts and a gasket and hence is even more economical to construct. The fluid passages in each embodiment are large, thereby imposing little restriction to flow; while the tortuousdirection of the passages makes for high turbulence. The passageways, while of approximately constant area at all points, have different shapes at various sections along the line of flow. This makes for high turbulence with a minimum of resistance. There are no dead ends or pockets.

It is usually convenient to have all fluid connections in a single member of the apparatus.

The heat exchanger can be opened for cleaning without disturbing any pipe connections. This easy accessibility makes the apparatus particularly useful in such relations as heating water containing temporary hardness which precipitates as scale. Cleaning of ordinary straight tube exchangers is difficult and coiled tube exchangers are almost impossible to clean in chanically.

My heat exchangers have special utility when installed in situations where they are required to reclaim heat from badly contaminated waste waters. There are no projections or dead ends to catch or collect suspended substances, e. g., lint and the like carried in, for example; laundry waste. Cleaning, which is frequently necessary in the case of ordinary tubular exchangers, is practically done away with. However, it is a simple matter to open up my exchangers for inspection or cleaning, if this is desired. The exchangers have been found useful in indirect heating of boiler feed water and in sampling boiler water.

' The exchangers are readily adaptable for construction in any metal that can be cast. The

exchangers can be made of cast iron, cast steel, brass, bronze or aluminum, depending on the service to which the exchanger is put. The iron can be readily galvanized or electroplated, as for example, chromium plated, when desired.

The heat exchange apparatus may I also be embodied in wrought or machined metal; or, in part, in pressed or stamped metal.

What I claim is: r

1. Heat exchange apparatus comprising a plurality of open grooved channeled members assembled into a unit, the unitary assemblage having therein two separate, tortuous, immediately adjacent fluid passageways running from one end of the unit to the other, the open channels of each member forming parts of both passageways in the unitary assemblage, the unit having conduit connections for each passageway and means for holding the members together.

2. The apparatus of claim 1 wherein two channeled members are provided, the two members cooperating to form the enclosed unit with the separate passageways therein.

3. The apparatus of claim 1 wherein the channel arrangement of each unit is the same.

4. Heat exchange apparatus comprising a plurality of members closed on one face'and provided with open channels on the other face, the members being assembled into a unit with the open faces juxtaposed, the unit having therein two separate, tortuous, immediately adjacent pas sageways for fluids running from one end of the unit to the other, the open channels of each memberforming parts of the fluid passageways in the unit, the. unit having conduit connections for each passageway and means for holding the members together.

5. Heat exchange apparatus comprising a plurality of open channeled members, a ported separator member, the channeled members and separator member being assembled into a unit, the open channels of each member and the ports in the separator member forming in the unit two separate tortuous, immediately adjacent passageways for fluids running from one end of the unit to the other, the unit having conduit connections for each passageway and means for holding the members together.

6. The apparatus of claim 5 wherein the pnsageways are approximately helical in course.

7. The apparatus of claim 5 wherein the passageways are approximately helical in course and the channels of each member are approximately parallel to each other and inclined to the longitudinal axis of the member.

8. Heat exchange apparatus comprising a plurality 'of'members assembled into a unit, each member having a casing portion and an opened channeled portion cooperating in the assembled unit to form two separate, tortuous immediately adjacent passageways for fluids, one of said members having fluid connections for all the several fluids.

9. A heat exchanger comprising in combination two opposed members provided with a plurality of adjacent fliiid-carrying channels, a separating member between the two members forming in combination with the channels two separate, continuous, adjacent passageways extending from one end of the members to the other end and means for compressing the two members and the interposed separating member together,ione of the members having fluid connections in communication with the channels.

10. A heat exchanger comprising in combina-.

tion a separator member having two open faces and comprising a casing portion and a partition system comprising a plurality of partitions integral with the member and forming an openfaced channel leadingfrom one. end of the memher to the other, and cover members for the open separator member for thechannels.

11. A heat exchanger comprising in combina-,

tion a separator member having a casing portion and a partition system forming two separate tortuous passages open on opposite sides and extending from one end of the member to the other,

with the separator member to form two separate conduits, and fluid connections for each end of the two conduits.

12. A heat exchanger comprising in combination twomembers each having a flat face with necting the overlapping ends of the cavities in the two members, the members and separating means forming two separate tortuous passages each comprising a plurality of cavities and a plurality of ports, and inlet and outlet connections at opposite ends of each passage.

13. A heat exchanger comprising inbombination two members each having a flat face and a plurality of cavities in the flat face, ported sep- 55 cover members for the open sides cooperating I arating means interposed between the fiat faces, the cavities being so arranged that each end of one cavity in-the one member overlaps one end of one of two cavities in the other member, said two cavities being spaced apart and separated by a third cavity in saidother member, the ports in the separating means establishing communication between the overlapping ends of the cavities in the two members. a

14. A heat exchanger comprising in combina tion two members each having a flat face and a plurality of cavities in the flat face, ported sep arating means interposed between the flat faces, the cavities being so arranged that one end of one cavity in the one member overlaps one end of one cavity in the other member and the other end of. said cavity in the one member overlaps one end of another cavity in the other member, the said two cavities in the other member being spaced apart by a third cavity in the other memher, the ports in the separating means establishing connection between the overlapping ends of the 10 cavities in the two members.

ERIC PICK.

Images