US2310970A - Heat exchanger - Google Patents

Description

Feb. 16, 1943. A, s, LlMPERT 2,310,970

HEAT EXCHANGER Filed May 28, 1941 Patented Feb. 16, 1943 UNITED STATES PATENT OFFICE HEAT EXCHANGER Alexander S. Limpert, Bay Shore, N. Y.

Application May 28, 1941, Serial No. 39517 3 Claims.

This -inventior relates to heat exchangers, more especially condensers for refrigeration and air conditioning purposes and has for its particular objects the provision of a highly efiicient, extremely sturdy and compact device which can be easily cleansed to remove externally deposited dust and other sediment and which is simple and cheap to manufacture especially since it requires but a relatively small amount, by weight, of metals of high conductivity in its construction.v Further advantages of my invention are hereinafter set forth.

Heretofore, as I am well aware, it has been proposed to scuff or strike up the surface of a condenser tube to form a series of spirally disposed rigid tapered spaced teeth which are of relatively thick cross section at the base thereof. The total weight of metal in such teeth is rel- "atively large as compared with the Weight of the filaments employed in my improved heat exchanger and furthermore, such teeth do not lntersect and contact with each other intermediate the ends thereof as do the aforesaid filaments of my heat exchangers buton the contrary, are separated from each other throughout the entire length thereof by air gaps of gradually increasing extent from the base to the tip of each tooth.

Certain preferred embodiments of my invention are fully set forth in the following detailed description and drawing forming a part thereof in which latter Figure 1 is an elevation, partly in section, of a condenser forrefrigeration or air conditioning purposes embodying my invention;

Fig. 2 is a fragmentary side elevation and Fig. 3 an end elevation of the tinsel garland element of such condenser, isolated and prior to being wound on the tubular support therefor,

Fig. 4 is a fragmentary side elevation and Fig. 5 is an end elevation of such garland, isolated from its support showing the position of 'the filaments in the garland after the same have folded on themselves preparatory to winding the garland on the supporting tubing;

Fig. 6. is an enlarged, fragmentary, vertical cross section and Fig. 'l is an enlarged fragmentary longitudinal section of one reach of tubing of such condenser wherein tinsel garland .is applied both externally and internally to such condenser and which form of condenser is especially adapted for cooling or heating non-condensable gases; and

Fig. 8 is a perspective view of the wiper slide employed for cleaning in situ the externally applied garland of the condenser.

Referring to the construction illustrated in the drawing, the reference numeral I designates the looped tubing of a condenser for refrigeration purposes, 2 the various supporting bars thereof which are brazed or welded to the opposing lateral extremities of such tubing; and the reference numerals 3 and 3' designatel external and internal radiation elements of high heat conductivity carried thereby, the same constituting so-called tinsel garland, which as is well known comprises a stranded wire core a to which are anchored a multiplicity of individual looped filaments b. Usually the core wires are reinforced by a covering of cotton threads to facilitate the drawing of the fine core wires through the tinsel making machines by relieving the strain on such wires during their passage therethrough. Each filament comprises a narrow fiat metal strip, centrally folded, which is desirably composed of copper plated with silver, such strips being desirably of a total length of about 3", extremely thin, but about 0.002 to 0.008 in thickness and but about 11g" wide, for example. These filaments are of remarkable flexibility and sufficient resiliency to spring back to their original position when distorted temporarily. The garland element 3 is spirally Wrapped on the tubing of the condenser, after rst bending the looped filaments outwardly in the manner illustrated in Figs. 4 and 5 and, when so wrapped certain filaments will intersect'or interlace with other adjacent filaments thereby establishing a multiplicity of contact points therebetween which materially enhance the heat exchange between the filaments and the tubing on which the garland is wrapped.

A wiper slide 5 of metal or plastic material is preferably removably mounted on said tubing.

. This slide has a series of holes 6 drilled therein each intersected by a slot 1 which is of sufiicient width to admit of the tubing being inserted therethrough into the holes 6. Each hole is of suiiiciently greater diameter than the external diameter of said tubing plus double the thickness of the wrapped filament a to admit of the free reciprocation of' the slide through the garland when it is desired to cleanse the same.

In the internal radiation element 3 the tinsel garland has the filaments thereof compressed and bent rearwardly as illustrated in Figs. 1 and 7. This internal radiation element is preferably only employed for heat exchangers wherein noncondensable gases are circulated since in the case of condensable vapors and liquids it is desirable to have the conduits of the tubing entirely unobstructed to facilitate the rapid circulation of the liquids therethrough.

Preferably, prior to the application of the tinsel garland to the tubing, the latter is coated with metallic paint, such as aluminum paint or some heat conductive adhesive, as designated by the reference numeral c, as the same not only tends to anchor or set the cores of the tinsel garland in situ on the tubing but also forms a heat conductive bond between the tinsel garland and the tubing since it eliminates air gaps between the tinsel core and the tubing besides enhancing, due to its own inherent heat conductivity, the heat transmission between the metal core of the garland, particularly where cotton threads are incorporated therewith, and the metal surface of the tubing because the cotton threads soak up the metallic binder and thereby their heat conductivity is substantially increased.

The wiper slide 5 which is adapted to be normally positioned at one end of the condenser serves as an effective cleanser therefor since it merely is necessary to slide the same back and forth over the tinsel garland in order to substantially completely eliminate any dust or other sediment deposited in the garland and, due to the inherent resiliency of the individual filaments of such garland, the same immediately resume their original position once they are relieved from the influence of the slide. Furthermore the operation of cleansing of such garland by reciprocation of the slide through the filaments thereof does not have any deleterious effect upon the filaments du'e to their remarkable durability and ready flexibility and as a matter of fact, unless the filaments were unusually durable and flexible so as to admit of the rapid sliding to and fro of either the wiper slide or the fingers, when enveloped thereby, it would be diidcult if not impossible -to effectively cleanse the filaments with the consequence that dust and kother sediment would gradually collect thereon and eventually would materially decrease the efficiency of the garland as a heat radiating medium.

The aforesaid tinsel garland possesses many advantageous characteristics which peculiarly adapt the same for use in heat exchangers as the radiation element thereof, for example due to the extremely small dimension thereof both as regards thinness and width, the same can be plated at an almost negligible expense with metallic silver which metal, as is well known, possesses a remarkably high co-efiicient of heat conductivity. Such plating also tends to increase the elasticity of the filaments thus insuring the quick restoration thereof to their original position when displaced longitudinally of the tubing during the cleansing thereof as aforesaid with a wipei` element or with the hand. Also the fact that the filaments project outwardly from the tubing in a plurality of different planes, the multiplicity of points of intersection thereof with adjacent filaments enhances the total coeflicient of heat conductivity of the garland radiation element, Again, the cheapness of assembly of the condenser unit is particularly important since it is but a simple matter to Wind the tinsel garland on the tubular support either by hand or simple winding equipment, such as a bobbin rotatably mounted on a revolving arm, and therefore no dies or complicated machinery are required in order to rapidly manufacture the complete condenser on a. large production scale. As a consequence, such condenser can be manufactured by a manufacturer of refrigeration or air conditioning equipment since not only, as above stated, are no special dies or complicated machinery required, but no highly skilled labor need be employed in such production owing to the ease of applying the garland to its tubular support.

While in the preferred form of condenser illustrated herein the tubular support comprises tubing having a plurality of return bends formed thereon which form parallel reaches of such tubing obviously, if desired, the tubing could be wound as a pancake spiral and with the coils thereof spaced sufficiently apart to admit of the application of tinsel garland thereto. Also, it is, of course, understood that the condensers may be constructed of several parallel reaches of tubing each wound with garland.

The aforesaid condenser construction is remarkably efficient, being equal or even superior to condensers formed from tubing having metallic fins applied thereto, such as the honeycomb type of condenser for example, which fin type of condenser is almost invariably manufactured by concerns specializing therein because of the complicated machinery and highly specialized training on the part of the operators required in such manufacture.

While in the tinsel garland such as used for decorative purposes and the like and which is also suitable for use in my condenser construction, cotton threads or cords are wrapped around the metal core thereof, for the reasons heretofore explained, nevertheless other garland, if desired, may be employed, such as the type known as printers garland, which has thicker and longer filaments than those used in decorative garland although, due to the excellent heat conductivity, cheapness and durability of the ordinary garland, such as used for decorative purposes as above specified, particularly during the Christmas season, I have found that the same is especially desirable for use in the manufacture of condensers and radiators such as aforesaid.

Various modifications of the above described heat exchanger construction may be made without departing from the spirit of my invention as embraced within the scope of the appended claims.

Having thus described my invention, what I claim is:

1. In a heat exchanger, the combination comprising a tubular support having a rope of tinsel garland wound thereon and secured thereto.

2. In a heat exchanger, the combination comprising a tubular support having heat radiation means spirally wound thereon, which comprises essentially tinsel garland having a metal core and a multiplicity of flat, extremely thin metallic filaments extending outwardly therefrom in a plurality of different planes, such filaments being elastic, highly flexible and of a thickness of the order of between 0.001" and 0.01.

3. In a heat exchanger, the combination comprising a tubular conduit for fluid having a rope of tinsel garland spirally wound thereon, said garland having a stranded core and a multiplicity of iilamentary, metallic heat radiating elements projecting outwardly therefrom, said core being united in good heat conductive relation to the external wall of said tubing by a metallic bonding medium.

ALEXANDER S. LIMPERT.

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