US2449822A - Heat exchanging apparatus - Google Patents

Description

L. B. SCHIBBYE HEAT EXGHANGING APEARATUS Filed' Jag. 28. 1944 Sept. 21,` 194s.

msg 4 Patented Sept. 2.1,

man:` EXCHANGING APPARATUS Laurita Benedictus Schlbbye, Essvik, Sweden, ase l I signor to Svenska Cellulosa Aktiebolaget, Stock- `holm, Sweden, a company of Sweden Application January 28, 194e, vSerial No.

' In Sweden December 11, 1942 1 claim. (ol. 25a- 229) The present invention relates to a heat exychanger of the type in which the mediums between which the heat transfer isto take place. are subiected to helical or spiral motion. As a rule, heat exchangers of this ltype give a high eillciency, but the embodiments hithertoknown have certain in' herent disadvantages and limitations. Thus, they are not suitable for mediums which yield deposits in the form of incrustations, soot or the like. They Vare diillcult to repair and the joints and connections are diillcult 4to pack so as to be' perfectly tight.

The primary object of the 4present invention is to provide a heat exchanger of the abovemen- .tioned :type by means of which these disadvantages are eliminated or at least considerably reduced. A main feature of the invention is that it includes -a casing or tube -and a body therein, the body having a substantially helical internal passage (or passage system) for one medium and yproviding a substantially helical external passage (or passage system) for another medium.

An object of the invention is to further improve the heat transfer from one medium to the other by avoiding the double walls in the path along which the heat transfer takes place.

Another object is to provide a large cross-sectional area particularly for the external passage so that a great speed throughjthe exchanger can be given to the medium flowing through the said passage, particularly if it is a gas. This can be done by providing two or more helical ducts and by giving one of lthe passages a cross-sectional area which is at least twice as large as that of the other.

A further object is to'provide a heat exchanger which is easy to disassemble, in order to externally clean the inset body and internally clean the casing or the tube. With such a heat exchanger it is only necessary to avoid the use of a medium and comprising three helical or spiral coilsA threaded one into the other. I

Fig. 2 is a'sectlon of the apparatus online II-II of Fig. 1. A

VFig.I 3 is a longitudinal section of part of another embodiment in which Ithe interior body is :a single coil.

Fig. 4 is a similar section of an apparatus with a single coll and of a modiiled embodiment of the Itwo halves as will be seen from IFlg. 2, and hav# ing the detachable cover 2 and the detachable bottom 3. Near its upper end the casing has a flange tube 4 for the connection of a pipe line, and near its lower end .there is a similar flange tube 5. The casing encloses three fiat hollow coils I6, T, 8 screwed into one another. Therst coil is fixed to an axial center tube 9 forming the core of the coil body, while the other coils 1, 9 are not at- .tached to the center tube and may be screwed into lthe rstmentloned coil. The three conduits thus obtained are connected to an upper header I3 by means of suitable end portions I0, I I, I2, see also Fig. 2. By means of a neck` I4 this header communicates with an opening I5 in the cover 2.

At the bottom the conduits have similar radial end portions I'B, I'I, I8 connected to a lowerI header I9 in the casing I. Through a neck 20 this header communicates with an opening 2l in the bottom 3 and an extra chamber 22 with an opening 23, the said chamber being situated below .the said header I9.

The exchanger described operates in the following manner:

One of the mediums participating in the. heat exchange is admitted, for exam-ple, through the opening 23, ypasses ,through the chamber 22 and a heat exchanger embodying the invention, the

interior body being shown generally in elevation enters lthe lowerheader I9 from which the me- -dium is distributed to the three conduits 8, 1, I through the connections IIS, I1, I8. HavingI passed the said conduits the medium, vla the connections I0, II, I2, enters the upper header I3 which thus forms an outlet header for the different medium currents, from which header the collected medium leaves through the opening I 5 and a pipeline connected thereto, not shown. i

-The second medium is admitted for example through the flange tube I and thus enters the casing I in which the medium passes vthrough the intermediate spaces between .the convolutions of the openings or manholes.

-what exaggerated in Fig. 1.

andasse coils 6, '8. This medium then leaves through the flange tube 5. Y

Both of the mediums are forced to pass a long distance 4through the apparatus and in suitably thin layers, and therefore the heat exchange becomes efllcient even in an apparatus of moderate dimenstions.

In order to clean the apparatus. the two parts of the casing are taken apart after the cover and/or the bottom have been removed.

If desired, the casing may be made up of a plurality of sectional wall elements or parts in such a way that only one or more parts need be removed pipes and the liquid inside thereof. Further,

for the cleaning of the interior of the casing and the exterior of the conduits. The said part or parts may preferably have the form of cleanout The connection between the header I3 and the cover may be such that the header and the coils can be lifted from the casing by raising the cover.

The cover, the bottom and the remaining parts of the casing may -be designed, as to material and thickness thereof, for adequate strength to permit -a substantial pressure on the medium flowing .through the passage or passages on the outside of the inset body, and the pressure on the-medium flowing through the conduit or conduits of the inset body may then be substantially higher, for any given strength of the wall-s of the inset body. than would be practical in the absence of a substantial pressure at the exterior of the inset body.

Thecoils may extend to .the wall of the casing or, in order to compensate for unequal expansion, may end at some distance therefrom as is some- Through the intermediate spaces impurities which by the centrifu gal force of the spiral motion are thrown toward-s the wall of the casing, sink downwards and may be removed from the lower portion of the casing. To facilitate the. separation and removal of the impurities the wall of the casing may be provided with grooved bulges running parallel with the intermediate `spacesbetween the winding convolu tions, as indicated at in Fig. 4. Only one helical or spiral coil is shown in this figure. The said coil is made without a core. Moreover, there may be any number of coils in the same'casing. The said grooves 25 in which the heavy impuri-ties gather, may be vprovided with cleaning openings or blow-out pipes at suitable points.

As indicated in Fig. 3, inspection glasses 26 are provided where necessary, to permit observation of the interior of the exchanger.

Itis to be noted that the invention is vnot lim-v itecl to a particular shape or geometry of the heat exchanger and that it may be embodied in apthe passage area of the external pass-age should preferably diminish in .the ow direction of .the gas corresponding about to the volume reduction of the gas caused bythe fall of temperature. This ter. vOf course, the case will be the reverse if the heat absorbing medium the volume of whichincreases in the flow direction, passes around the coils. The main point is that the passage area decreases or increases according to the volume change of the medium in the ow direction.

Having now ldescribed my invention, what I claim as new and desire to secure by Letters Patent 1S: y o

A heat exchanger comprising a substantially cylindrical shell, a plurality of conduits Within saidv shell, each conduitl being in the form of a substantially right helicoid and said helicoids -being concentric and of equal size and pitch land the turns thereof being equally spaced from each other thereby forming -a plurality of helicoidal 'passageways of substantiallyuniform cross-sec- `tional shape through said cylindrical shell. the

paratus of other form than the illustrated embodiments in whichthe casing has -a cylindrical shape, and the outer periphery of the coils lies in a cylindrical surface.

When heat is transferred from gases to a liquid, from exhaust gases o r water vapor to water, for example, it is suitable to permit thegas or gases to pass outside of the convolutions of the pipe or cross-section of each conduit as cut by a plane 'through the axis of the cylinder being substantialhr rectangular and -the dimension of said crosssection perpendicular to the axis of .the cylinder being substantially equal lto the' radius of the cylind-rical shell and at least several times the dimension of the cross-section of the conduit parallel to the axis of the cylindrical shell, means for passing a fluid through said conduits and means for passing another fluid through said passage- Ways.

LAURITZ BENEDICTUS SCHIBBYE.

REFERENCES orrnn Thel following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name y Date n 205,153 Tregent June 18, 1878 410,287 Kuhn Sept. 3, 1889 441,371 Morrell Nov. 25, 1890 A 851,985 Goldfein Apr. 30, 1907 1,280,656 Buhr Oct. 8, 1918 1,621,374 McPhee Mar. 15, 1927 1,725,549 Swenson Aug. 20, 1929 1,799,039 Conejos Mar. 31, 1931 1,852,489 Sullivan Apr. 5, 1932 1,852,490 Sullivan Apr. 5, 1932 1,868,271 Boehm July 19, 1932 1,892,778 Bla-ck Jan. 3, -1933 1,985,785 Kellogg Dec. 25, 1934 2,012,920 Summerfield Aug. 27, 1935 FOREIGN PATENTS Number Country Date 29,061 Great Britain Dec. 16, 1913

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