US2882022A - Heat exchanger - Google Patents

Description

F IG. 2.

INVENTORS L H GREATHOUSE SMITH ROBINSON C H. HAYDEL K q ATTORNEY B A H.M.

- April 14, 1959 L. H. GREATHOUSE ETAL HEAT EXCHANGER' OfiginaLFiled Aug. 26, 1952 FIG. 1.

United States Patent HEAT EXCHANGER Lucien H. Greathouse, Burns Ashby Smith, Helen M. Robinson, and Chester H. Hayde], New Orleans, La.

Original application August 26, 1952, Serial No. 306,517,

now Patent No. 2,744,014, dated May 1, 1956. D1- vided and this application August 2, 1955, Serial No.

1 Claim. (Cl. 257-1) (Granted under Title 35, U. S. Code (1952), see. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to a heat exchanger of the general type in which a tank is provided with inlet and outlet openings comunicating with the tank for passage of the heating fluid, and with at least one heat exchanger tube in the tank having inlet and outlet openings comunicating with the tube arranged for flow of the liquid to be heated through the tube.

According to the invention means is provided for clean ing adhering deposits from the inside surface of the tube. Such means comprises, in general, a scraper in the form of a flexible, circular split band bearing against the inner surface of the tube and being open so that deposits may be removed from the inner surface of the tube by longi tudinal movement of the scraper while allowing a substantial non-turbulent flow of the liquid being heated past the band. The scraper is attached to a handle which extends through an opening in the tank in line with the tube. The ends of the band are slidingly joined, permitting it to undergo small adjustment to conform to the size of the tube and still scrape it efiectively.

The heat exchanger of the present invention is particularly useful in the heating of fine starch fruit water such as that obtained in the production of sweet potato starch. The heat exchanger may be operated continuously and the heat exchanger tube efliciently kept clear of deposits, thus keeping constant the heat exchange rate. Deposits tend to insulate the tube so that the build up of deposits detrimentally varies the heat exchange characteristics of the exchanger. In case of heating fine starch fruit water, it is desirable to keep the water in a non-turbulent state.

For a detail description of the invention reference is made to the accompanying drawing in which Fig. 1 is a vertical section of the exchanger on line 1--1 of Fig. 2;

Fig. 2 is a horizontal section on line 2-2 of Fig. 1;

Fig. 3 is an elevation of the scraper with parts broken away; and

Fig. 4 is a section on line 4-4 of Fig. 3.

Tank of the exchanger is provided with inlet and outlet openings 11 and 12 for passage of the heating fluid. Headers 13 and 14 and a number of vertical heat exchanger tubes of usual construction are provided. The liquid to be heated enters through inlet 15 flows upward through the tubes and discharges through outlet 16. The several tubes and associated scrapers are similar and only one tube and its associated scraper 21 will be described in detail.

The scraper is provided with a flexible circular split band 22, preferably of spring steel. The ends of the 2,882,022 Patented Apr. 14, 1959 band overlap and are slidingly joined, outwardly projecting pins 23 and 24 affixed to the innermost end operating in elongated slots 25 and 26 in the outermost end to hold the ends in alignment. The band bears against the inner surface of the tube, the lower edge of the band being beveled inwardly to guide its entrance into the tube. Handle 30, in form of a rod, extends upwardly through opening 31 in the tank, the lower end of the handle being attached to the band. The handle is of such length as to provide for movement of the scraper throughout the length of the heat exchanger tube.

The handle is attached to the scraper in a manner to allow free flexing of the band, thus to permit the band to bear against the inner surface of the tube and adjust to slight irregularities, and also to permit a substantial nonturbulent flow of the liquid being heated past the band. To this end cross straps 32 and 33 are attached to their outer ends to the upper edge of the band at diametrically opposed points remote from the split ends. The inner ends of the straps overlap and are provided with elongated slots through which the handle is loosely passed. Straps 35 and 36 of spring steel are attached at their upper ends to the band, the lower ends being afiixed to the lowermost end of the handle as by welds 37 and 38.

Sludge which collects in the bottom of the heat exchanger may be discharged through sludge valve 40.

This application is a division of application Serial No. 306,517 filed August 26, 1952, now Patent No. 2,744,014 issued May 1, 1956.

Having thus described our invention, we claim:

A heat exchanger comprising a tank, at least one heat exchanger tube within said tank, inlet and outlet openings communicating with the tank, inlet and outlet openings communicating with the tube and arranged for fiow of liquid to be heated, an opening in the tank in line with the tube, a handle extending through the opening, and a scraper attached to the handle within the tube for removal of deposits from the interior surface of the tube, said scraper comprising a flexible, circular split band, the ends of the band being slidingly joined, permitting the band to undergo small adjustment to conform to the size of the tube and still scrape it effectively, the band bearing against the inner surface of the tube and being open so that the deposits may be removed from the inner surface of the tube by longitudinal movement of the scraper while allowing a substantial non-turbulent flow of the liquid being heated past the band.

References Cited in the file of this patent UNITED STATES PATENTS 13,628 Weissenborn Oct. 2, 1855 273,777 Strong Mar. 13, 1883 321,541 Shepard July 7, 1885 440,410 Nelson Nov. 11, 1890 443,186 Alberger Dec. 23, 1890 810,441 Stump Jan. 23, 1906 1,116,953 Testrup Nov. 10, 1914 1,581,545 Prache Apr. 20, 1926 1,621,289 Sternberg Mar. 15, 1927 1,668,577 Vecchio May 8, 1928 1,686,715 Smith Oct. 9, 1928 1,770,208 Kemnal July 8, 1930 2,233,066 Watson Feb. 25, 1941 2,733,767 Sappington Feb. 7, 1956 OTHER REFERENCES Babbit: Sewerage and Sewage Treatment," 6th ed. (1947), published by Wiley & Sons (N.Y.), p. 397 (first full paragraph).

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