US3513908A - Embedded tube heat exchanger - Google Patents

Description

May 26, 1970 G. B. SINGH EMBEDDED TUBE HEAT EXCHANGER Filed Aug. 18, 1967 INVENTOR GURU B. SINGH WM Ill ll/f ATTORNEY 3,513,908 EMBEDDED TUBE HEAT EXCHANGER Guru B. Singh, 6329 31st Ave., Kenosha, Wis. 53140 Filed Aug. 18, 1967, Ser. No. 661,572

Int. Cl. FlSd 1/02; F28f 13/06 US. Cl. 165-109 1 Claim ABSTRACT OF THE DISCLOSURE A device for transferring heat between a portion of the exterior walls and adjacent conductor surfaces of a first circuit enclosed within a second circuit. Increased contact of fluid in the second circuit with the exterior walls and adjacent conductor surfaces of said first circuit results from surrounding the enclosed portion of the first circuit with a porous substance consisting of a layer of finely divided metallic particles. To overcome the tendency of fluid thus restricted to establish fixed passages when flowing between such metallic particles, a core having helically arranged radial ribs is inserted to interrupt the laminar fluid flow just prior to entry of such fluid into such particles.

BACKGROUND OF THE INVENTION Field of the invention This invention pertains to the art of transferring heat energy from one fluid substance to another by passing the first such fluid substance through the second.

Description of prior art The art of positioning one section of a first conduit within a second conduit such that fluid flowing through the first will gain or lose heat from or to the second, is well known. It is also well known that some means for transforming laminar flow through the second circuit to a turbulent flow substantially increases the heat transfer efliciency of the exchanger. Such increase in efliciency is attributable to the increased number of particles of a second circuit fluid which are brought into proximity with the walls of the first circuit. Use of a granular substance having a great number of granules and corresponding interstices to surround the first circuit creates multiple avenues through which second circuit fluid flows, thereby breaking up laminar flow. However, the improvement in efficiency of heat exchange resulting from introduction of such multiple avenues is limited inasmuch as the newly created multiple avenues become fixed and maximum turbulence is not produced. It is apparent that the need is for means for approaching completely random motion of the fluid through the interstices in order that maximum contact between units of second circuit fluid and the walls of the first circuit and conductor surfaces adjacent thereto, will result.

SUMMARY OF THE INVENTION The foregoing background illustrates the state of the heat exchanger art at the time of the applicants instant invention. Through such invention means is provided for directing fluid through a series of small passages in a medium surrounding a completely separate fluid circuit, such that the passages followed by such fluid are con stantly changing in a random pattern producing maximum turbulence in the fluid flow. The production of maximum turbulence in such flow constitutes the principal object of this invention. A further object of this invention is to provide a helically curved obstruction in the path of fluid flow in one of the fluid circuits of a heat exchanger such that the curvature of such obstruc- United States Patent 3,513,908 Patented May 26, 1970 "ice tion will provide maximum turbulence without a substantial pressure drop within the circuit.

In the attached drawings and following description, the best mode presently contemplated for carrying out the invention is set forth. The manner and process of making and using the invention is described below in such full, clear and concise and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the invention. It should be emphasized, however, that the subject matter regarded as the invention is not limited solely to the here described embodiment of it, but rather includes everything falling within the claims set forth at the conclusion of this specification.

FIG. 1 is a cross sectional view of the heat exchanger incorporating a form of the invention.

FIG. 2 is a cross sectional view taken along the line 22 of FIG. 1.

FIG. 3 is a perspective view of the helically ribbed core removed from the heat exchanger.

Referring now to the drawings in detail, FIG. 1 shows a first fluid circuit 16 having inlet 5, continuous coils 4, and outlet 6. FIG. 1 also shows a second circuit 17 comprising inlet 8, outlet 9, an inner cylinder 15 with solid end walls 10 (through which inlet 8 opens) and 11 and porous side walls 3 in which the coils of circuit 16 are located; and an outer cylinder 14 with solid side walls 1 and solid ends 13 (through which inlet 8 extends into cylinder 15) and 12 (through which outlet 9 extends from cylinder 14).

Inside cylinder 15 is ribbed core 18 consisting of longitudinal shaft 19 from which radially project longitudinal ribs 7. Each such rib is formed as a helix longitudinally of shaft 19, preferably having 10 of curvature for each inch of shaft length. As fluid in closed fluid circuit 17 enter inlet 8, laminar flow is altered by the effect of ribs 7 and shaft 19 such that turbulence is created prior to entry of the fluid into side wall 3 of cylinder 15. Side wall 3 is composed of a porous substance, preferably sintered metallic particles of nickel plated copper having a high resistance to corrosion. Turbulent flow of fluid from ribs 7 enters side wall 3 in random directions. This results in a continuous penetration of said fluid into substantially all of the spaces between particles in wall 3 enabling the conducting properties of said wall 3 to act in exchanging heat with the passing fluid to a maximum extent.

After penetration of the pores in wall 3, fluid in circuit 17 passes into space 2 and leaves cylinder 14 through outlet 9.

It will be observed from the foregoing description that this heat exchanger is readily adaptable for manufacture with varying circuits proximate to each other, and with alternate devices for positioning ribs within such circuits, or at least one such circuit, to produce the necessary turbulence. Likewise, use of any porous substances which have suitable properties of heat conduction may be substituted for sintered metallic particles described above. While I have illustrated a preferred embodiment of the invention, many other modifications may be made without departing from its spirit.

Accordingly, I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all embodiments which are reasonably covered by the appended claim.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a heat exchanger, the combination of:

a first closed circuit having tubes wound in the form of a coil with exposed surfaces embedded within a layer of finely divided metallic sintered nickel plated copper particles forming the wall of a cylinder having an opening for introduction of a fluid,

a first fluid for flow within said first closed circuit,

a second closed circuit entirely enclosing the exposed surfaces of said coil and said cylinder wall such that interstices in said cylinder wall comprise the sole communication between two lateral sections of said second closed circuit,

a second fluid -for flow within said second closed circuit,

means for directing the entire fluid flow in said second circuit through said cylinder wall, and

deflector means in said second circuit within said cylinder and adjacent the exposed surfaces of said cylinder wall comprising a core with helical ribs fixed thereto arranged along its longitudinal axis in the form of a spiral in which each such rib has a curvature of 10 for each inch of length.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 7/ 1924 Great Britain. 6/ 1938 Great Britain. 7/ 1966 Great Britain.

ROBERT A. OLEARY, Primary Examiner A. W. DAVIS, JR., Assistant Examiner US. Cl. X.R.

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