US3768172A

US3768172A - Tornado flow separator for processing fine-grain or granular material

Info

Publication number: US3768172A
Application number: US00198627A
Authority: US
Inventors: H Klein; R Pieper
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1971-07-30
Filing date: 1971-11-15
Publication date: 1973-10-30
Anticipated expiration: 1990-10-30
Also published as: HU164322B; GB1378877A; JPS5124153B1; DE2138165A1

Abstract

In tornado flow dryers operating on helical flow or annular flow principles, excess drying media are withdrawn during operation of the dryers from the axial region of the drying chamber. The means for withdrawing the excess drying media is in the form of a pipe extending into the drying or reaction chamber along at least half of the length thereof, the pipe being provided with additional exhaust openings distributed over the length thereof.

Description

United States Patent 1191 Klein et a1.

[ TORNADO FLOW SEPARATOR FOR PROCESSING FINE-GRAIN OR GRANULAR MATERIAL [75] Inventors: Heinrich Klein; Rudolf Pieper, both of Erlangen, Germany [73] Assignee: Siemens Alrtiengesellschait, Berlin and Munich, Germany [22] Filed: Nov. 15, 1971 [21] Appl. No.: 198,627

[30] Foreign Application Priority Data July 30, 1971 Germany P 21 38 165.7

[52] 15.8. C1. 34/57 E, 55/410 [51] Int. Cl. F261) 17/10 [58] Field of Search 34/10, 57 R, 57 E;

[56] References Cited UNITED STATES PATENTS 8/1971 Klein 34 5712 5 1941 Peebles ..34 571-:

[ Oct. 30, 1973 8/1965 Oehlrich et a1. 55/410 X 3,199,268 3,494,047 2/1970 Geiger et a1 34/57 E FORElGN PATENTS OR APPLICATIONS 1,257,690 2/1961 France 55/410 OTHER PUBLlCATlONS Primary Examiner-William F. ODea Assistant ExaminerWilliam C. Anderson Attorney-Arthur E. Wilfond et a1.

57 1 ABSTRACT In tornado flow dryers operating on helical flow or annular flow principles, excess drying media are withdrawn during operation of the dryers from the axial I region of the drying chamber. The means for withdrawing the excess drying media is in the form of a pipe extending into the drying or reaction chamber along at least half of the length thereof, the pipe being provided with additional exhaust openings distributed over the length thereof.

7 Claims, 3 Drawing Figures PATENIEDncI 30 ms sun-:1 2 er 2 TORNADO FLOW SEPARATOR FOR PROCESSING FINE-GRAIN OR GRANULAR MATERIAL The invention relates to a tornado flow separator for processing fine-grain or granular particulate material by means of at least one gaseous medium, especially for the purpose of drying the particulate material Such tornado flow separators are known per se and include a cylindrical reaction or vortex chamber with supply inlets for the gaseous media disposed in and extending tangentially to the wall or casing of the reaction chambet and at least one supply inlet for the particulate material disposed at an incline and tangentially to the chamber wall in the upper region of the chamber, and at least one outlet for the processed particulate material in the lower region of the reaction chamber, as well as axially disposed means for withdrawing the excess and/or spent gaseous media. The tornado flow principle involves so-called relative forces in flowing media subjected to a rotational flow having a potential flow component and a circulatory flow component and resulting in vortex source and sink formation within the vortex chamber. The physical principles of this type of separation and the forces resulting from the foregoing flow phenomena are explained in greater detail in US. Pat. No. 3,199,268 to Oehlrich et al. and in US. Pat. Nos. 3,199,269 through 3,199,272, among others, which are assigned to the assignee of the invention of the instant application.

The tornado flow itself is formed of an outer substantially helical potential circulatory flowand an inner rotational flow traveling substantially helically and in the same direction as the potential circulatory flow, the

axial flow components of, the potential circulatory flow and of the inner rotational flow are in opposite directions. The particles to be separated are carried radially outwardly from the inner rotational flow. in direction toward the wall. or housing of the vortex chamber and are removed through an annular discharge slot surrounding the axial inlet duct.

A so-called helical flow dryer is known, wherein tangential jets in the reaction chamber wall orcasing are downwardly inclined and are disposed in a helical or sinuous path about the periphery of the chamber wall. The particulate material introduced at the upper end of the chamber is thereby collected alonga helical path in the vicinity of the chamber wall and guided downwardly. In a dryer based on the second operating principle mentioned hereinabove, namely the so-called annular flow dryer, the jets are disposed tangentially to the reaction chamber wall in planes extending perpendicularly to the axis of the tornado flow separator. Accordingly, the supplied particulate that isto be processed, collects in ring-shaped free-floating, rotating concentration between respective adjacent rows of jets. By controlling the quantity of air flowing through these jets or by overloading the individual rings of particulate material, these rings travel downwardly in leaps and are, in this manner, delivered for processing or drying.

A factor which determines the length of time that the particulate material is to be subjected to processing or treatment in the reaction chamber is the length of the chamber along which the gaseous media are supplied. Attention must also be given, however, to the proportion of the supplied volume of gaseous media to the throughput volume thereof, when the quantity of particulate material is to be treated in one pass in the reaction chamber. This means that a limit is imposed upon 2 any extension of the period of time during which the particulate material is to be treated or processed in the drying chamber by making the overall apparatus longer, because then, too large a volume of the gaseous media flows into'the reaction chamber which can no longer accommodate it. It has been common practice, heretofore, to remove excess and previously spent quantities of gas through an exhaust at an end of the reaction chamber. In the case of large quantities of exhaust which require an increased exhaust flow velocity of the gas, variations in flow are produced within the reaction chamber, so that reliable control of the particle rings or of the particle helices is no longer assured.

It is accordingly an object of the invention to provide a tornado flow separator having a reaction or vortex chamber wherein continuous removal of the excess gas volume is possible without varying the flow pattern in the reaction chamber.

With the foregoing and other objects in view, there is provided, in accordance with the invention, tornado flow generator for processing fine-grain or granular particulate material with at least one gaseous medium, such as for drying the particulate material, comprising a reaction chamber'having a substantially vertically extending axis and defined by a cylindrical chamber wall, supply inlets for gaseous medium disposed in and extending tengentially to the cylindrical wall, at least one supply inlet'for particulate material disposed at an incline and tangentially to the chamber wall, at an upper region of the reaction chamber, at least one outlet for particulate material that has been processed in the generator located 'at a lower region of the reaction chamber, and means for withdrawing excess and spent gaseous media from the reaction chamber, the withdrawing means comprising an exhaust pipe extending into the reaction chamber along the axis thereof for at least half of the length of the reaction chamber, the pipe being formed with a plurality of exhaust openings distributed overthe length thereof.

Due to the fact that the gases are exhausted in different regions of the reaction chamber, through the plurality of openings formed in the axial .pipe, the ring or helix-forming flow at the wall of the reaction chamber is not affected or altered butis instead maintained in the desired form over the entire length of the chamber.

In accordance with another feature of the invention,

the exhaust pipe is of slightly conical construction and tapers downwardly toward the open end thereof which extends into the reaction chamber. However, it is also possible, further in accordance with the invention, to provide an exhaust pipe formed of several individual coaxially disposed pipes of varying lengths'that are mutually telescopically displaceable with clearance therebetween, th clearance between the respective adjacent telescoping pipes serving as annular exhaust openings for the gaseous medium.

In order to be able to'supply to the reaction chamber gaseous media of varying temperature or of varying composition, and in accordance with a further feature of the invention, at least one annular diaphragm is disposed on the outside of the exhaust pipe so as to define with the inner surface of the reaction chamber wall, an annular gap. In accordance with yet another feature of the invention, there is disposed above the outlet for the particulate material, a diaphragm for deflecting the gaseous media so that the outlet is largely shielded from the gases.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in tornado flow separator for processing fine-grain or granular material, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of the specific embodiments when read in connection with the accompanying drawing, in which:

FIG. 1 is a diagrammatic view of a tornado flow generator in the form of a ring-flow dryer having a substantially conical exhaust pipe;

FIG. 2 is a diagrammatic view similar to FIG. 1 of another embodiment of the invention showing a tornado flow generator in the form of a helical-flow dryer having a telescopic exhaust pipe; and

FIG. 3 is another view of FIG. 2 showing a modification of the helical-flow dryer wherein the reactor chamber is sub-divided by annular diaphragms.

Referring now to the drawing and first, particularly to FIG. 1 thereof, there is shown therein a tornado flow generator or separator having a cylindrical reaction or vortex chamber 1 provided with jets 2 extending tangentially to the cylindrical wall of the chamber 1 and disposed in planes extending perpendicularly to the substantially vertical axis of the reaction chamber 1. A gaseous medium is introduced into the reaction chamber 1 through the jets 2 for the treatment or processing, such as drying of the fine-grain or granular particulate material supplied to the reaction chamber 1 through the inclined and tangentially disposed inlet 3. The particulate material flowing in through the inlet 3 collects, by the action of theflow developing in the reaction chamber 1 into free-floating, rotating rings 4 of particles, between each two individual rows ofjets. By shutting off individual rows of jets, the ring 4 of particles located above the respective, shut-off row of jets then drops farther down to the next lower ring region. However, it is also possible, by supplying further particulate material to the'reaction chamber, to effect a so-called jump or leap of the ring, a phenomenon which always occurs when the absorption capacity of a ring is exhausted, and that ring then passes on excess material to the ring next below the same. After passing through the entire reaction chamber 1, the treated or processed particulate material leaves the reaction chamber through a discharge outlet-5 at the bottom thereof as viewed in FIG. 1.

In order then to be capable of effecting the treatment or'processing of the particulate material even in a very long reaction chamber wherein a very great amount of gaseous medium flows into the reaction chamber through the individual rows of jets, there is disposed, in accordance with the invention, along the axis of the reaction chamber l, an exhaust pipe 6 which extends at least to the middle of the axial length of the reaction chamber 1 and is open at the lower end 7 thereof, as viewed in FIG. 1. At varying levels of the exhaust pipe 6, slots 8 are formed in the wall thereof, through which gaseous medium can be exhausted at the corresponding varying levels of the reaction chamber 1, in addition to the open lower end 7 through which gaseous medium is exhausted. Through this partial removal of excess and/or spent gas from the reaction chamber at varying levels, the flow devloped for controlling and guiding the rings of particles is not changed, so that the manner of functioning of the tornado flow separator is fully maintained. By means of this exhaust device of the invention, more space is provided for new, succeeding gaseous media, so that treatment or processing of the particulate material can be effected over a greater distance than was possible with the apparatus known heretofore.

In FIG. 2 there is shown tornado flow separator similar to that of FIG. 1, but including a so-called helicalflow dryer. The jets 9 of the embodiment of FIG. 2, while also disposed tangentially with respect to the wall of the reaction chamber 1, are not inclined perpendicularly but at an acute angle downwardly with respect to the axis, and are disposed along a helical or sinuous path on the peripheral surface of the chamber wall 1. The particulate material entering through the inlet 3 thereby travels along a helical or sinuous path 10 inside the reaction chamber 1 and accordingly passes continuously through the apparatus. The significance thereof is that the dwell time of the material in the reaction chamber 1 thus depends solely on the length of the developing helix, i.e., on the number ofjets located at the wall of the reaction chamber 1 and, therefore, on the overall length of the reaction chamber. In addition, the exhausting of the gaseous medium is effected, according to the invention, from the axial region of the reaction chamber 1. However, the exhaust pipe, in the embodiment of FIG. 2, is formed of a telescopic pipe 11 which is made up of three

individual tubes

12, 13 and 14 that extend, respectively, into the reaction chamber 1 with varying lengths. The individual tubes 12 to 14 are disposed at a given radial distance from one another, i.e., with clearance therebetween, so that excess media is exhaustible through the annular clearance or spacing between the tubes. According to the embodiment shown in FIG. 2, exhausting of the gaseous medium takes place not only at the lower, open end 15 of the inner tube 14, but also at the

locations

16 and 17, respectively, between the middle tube 13 and the inner tube 14, on the one hand, as well as between the outer tube 12 and the middltube 13, on the other hand. By telescopically shifting or displacing the individual tubes 12 to 14, exhausting of the gaseous medium can be assured at precisely predeterminable locations in the reaction chamber l. Also, the flow pattern proper for the maintenance of the helical concentration of particles is consequently not disturbed by the exhausting operation occurring at varying levels of the reaction chamber 1.

In FIG.'3, there is shown a helical flow dryer similar to that of FIG. 2, however, modified by annular diaphragms l8 and 19 which are additionally provided on the

individual exhaust pipes

13 and 14 so that, according to the embodiment shown in FIG. 3, three

reaction subchambers

20, 21, 22 are formed which are mutually partitioned from one another with respect to the air in the separator. These annular diaphragms l8 and 19 are constructed so that

annular gaps

23 and 24, respectively, are formed between the respective outer edges thereof and the inner wall surface of the reaction chamber 1, through which the particulate material to be processed can pass freely into the next succeeding subchamber, while the volume of .gas can be exhausted from that subchamber to the outside through the

aforementioned exhaust openings

16 and 17. By means of this disposition of annular diaphragms, it ispossible to supply the subchamber20, 21 and22 with varying gaseous media in which case, one group of jets 9, respectively, is surrounded by a

separate gassupply chamber

25, 26 or 27 and is supplied from the respective supply chamber with a gas of varying temperature or composition. The particulate material to be treated or processed can thereby be passed through zones of varying temperature.

There is also disposed in the embodiment of FIG. 3, an additional diaphragm 28 located above the particulate material discharge outlet 5 at the bottom of the reaction chamber 1 and serving to shield the discharge outlet 5 from the air flow within the reaction chamber 1, so that substantially only treated or processed material is discharged through the discharge outlet 5 and no additional volume of gas. 7

With the aforedescribed construction of the tornado flow generator or separator, a longer dwell time forthe particulate material to be treated is therefore provided in relatively simple manner due to the greater length of the reaction chamber 1, without having to consider imposing any limitation upon the volume of gas required for the treatment and the transport within the reaction chamber. In addition, it is possible; through the indicated subdivision of the reaction chamber, to treat the particulate material with different kinds of gases and with gases of varying temperatures without any intermingling of these different gas streams in the reaction chamber.

In the figures of the drawing, a reaction chamber 1 with a particulate material feed inlet at the upper end thereof and a particulate material discharge outlet at the lower end thereof are shown. However, it is also possible to operate the reaction chamber in a horizontal position or to set the chamber upside down so that the material travels from the bottom to the top thereof. Consequently, it is believed to be understood that the invention is not limited to apparatus in the manner actually shown in the drawing, but is applicable to all reaction chambers in which the material to be treated is transported on a defined path and in which use is made of central or axial exhausting gaseous medium.

We claim:

of excess and/or spent tangentially to said cylindrical wall, said supply inlets being disposed at axially spaced locations along said reaction chamber whereby floating paths of particulate material are formed between said axially spaced locations, at least one supply inlet for particulate material disposed at an incline and tangentially to said chamber wall at one longitudinal end region of said reaction chamber, at least one outlet for particulate material that has been processed in the generator located at a longitudinal region of said reaction chamber opposite said one longitudinal end, and means for withdrawing excess and spent gaseous media from said reaction chamber, said withdrawing means comprising an exhaust pipe extending into said reaction chamber along said axis thereof for at least half of the length of said reaction chamber, said pipe being formed with a plurality of exhaust openings distributed in axially spaced relationship over the length thereof, whereby gaseous medium introduced through said axially spaced supply inlets is withdrawn through corresponding adjacent axially spaced exhaust openings without impairing the flow of said free-floating paths of particulate material.

2. Tornado flow generator according to claim 1 wherein said longitudinal axis is substantially vertical, said supply inlet for particulate material is located at an upper region of said reaction chamber, and said outlet for particulate material is located at a lower region of said reaction chamber.

3. Tornado flow generator according to claim 1 wherein said exhaust pipe has an open end within said reaction chamber, said exhaust pipe being of slightly conical construction tapering toward said open end thereof.

4. Tornado flow generator according to claim 1 wherein said exhaust pipe is formed of a plurality of coaxially disposed pipes of varying lengths, said pipes 7 being mutually telescopically displaceable with clearcluding at least one annular diaphragm disposed on the l.Tornado flow generator for processing fine-grain or granular particulate material with at least one gaseous medium such asfor drying the particulate material, comprising a reaction chamber having a longitudinal axis and defined by a cylindrical chamber wall, supply inlets for gaseous medium disposed in and extending outside of said exhaust pipe so as to define with the inner surface of said chamber wall, an annular gap.

6. Tornado flow generator according to claim 1, including a diaphragm located above said outlet for particulate material for deflecting the gaseous media and shield said outlet therefrom.

7. Tornado flow generator according to claim 1 invarying characteristics to respectively different zones of said reaction chamber.

Claims

1.Tornado flow generator for processing fine-grain or granular particulate material with at least one gaseous medium such as for drying the particulate material, comprising a reaction chamber having a longitudinal axis and defined by a cylindrical chamber wall, supply inlets for gaseous medium disposed in and extending tangentially to said cylindrical wall, said supply inlets being disposed at axially spaced locations along said reaction chamber whereby floating paths of particulate material are formed between said axially spaced locations, at least one supply inlet for particulate material disposed at an incline and tangentially to said chamber wall at one longitudinal end region of said reaction chamber, at least one outlet for particulate material that has been processed in the generator located at a longitudinal region of said reaction chamber opposite said one longitudinal end, and means for withdrawing excess and spent gaseous media from said reaction chamber, said withdrawing means comprising an exhaust pipe extending into said reaction chamber along said axis thereof for at least half of the length of said reaction chamber, said pipe being formed with a plurality of exhaust openings distributed in axially spaced relationship over the length thereof, whereby gaseous medium introduced through said axially spaced supply inlets is withdrawn through corresponding adjacent axially spaced exhaust openings without impairing the flow of said free-floating paths of particulate material.

4. Tornado flow generator according to claim 1 wherein said exhaust pipe is formed of a plurality of coaxially disposed pipes of varying lengths, said pipes being mutually telescopically displaceable with clearance therebetween, the clearance between the respective adjacent telescoping pipes serving as annular exhAust openings for the gaseous medium.

5. Tornado flow generator according to claim 1, including at least one annular diaphragm disposed on the outside of said exhaust pipe so as to define with the inner surface of said chamber wall, an annular gap.

7. Tornado flow generator according to claim 1 including separate means for feeding gaseous media of varying characteristics to respectively different zones of said reaction chamber.