DEVICE FOR IMPARTING A TWIST TO A FLOW OF RAW GAS IN A TORNADO FLOW SEPARATOR
United States Patent 3744220
To impart a twist in an incoming flow of raw gas in a tornado flow separator, an inlet duct located within and coaxial to a vortex chamber is provided with at least one supply inlet for the raw gas extending tangentially thereto and communicating therewith. The inlet duct has a closed end which is substantially conical in shape.
US Patent References:
Apparatus for the separation of fluids
Blizard - June 1943 - 2320345
Device for increasing the total amount of separation of a vortex separator
Klein et al. - December 1967 - 3358844
Apparatus for the separation of fluids
Blizard - June 1943 - 2320345
Device for increasing the total amount of separation of a vortex separator
Klein et al. - December 1967 - 3358844
Application Number:
05/192142
Publication Date:
07/10/1973
Filing Date:
10/26/1971
View Patent Images:
Export Citation:
Assignee:
Siemens Aktiengesellschaft (Berlin, DT)
Primary Class:
Other Classes:
55/459.100, 55/458, 55/431, 55/426
International Classes:
B04C3/00; B04C5/04; B04C5/00; B04C3/06
Field of Search:
55/261,262,263,264,265,266,399,426,431,447,448,450,451,454,458,459,460,83 210/512 209/144
Primary Examiner:
Talbert Jr., Dennis E.
Claims:
I claim
1. In a tornado flow separator including a cylindrical vortex chamber defined by a cylindrical chamber wall, an inlet duct for raw gas to be purified in the separator disposed within and coaxial with the chamber at one end thereof, an outlet for gas purified in the separator located at the other end of the chamber, auxiliary gas supply inlets extending tangentially to the chamber wall in the vicinity of the purified gas outlet and being inclined with respect to the chamber wall so as to supply a flow of auxiliary gas to the chamber opposite in direction to the flow of raw gas therein, and means defining an annular discharge gap coaxially surrounding the raw gas inlet duct for discharging from the chamber particles separated from the raw gas supplied thereto, a device for applying a twist to the raw gas supplied to the separator comprising at least one raw gas supply tube connected tangentially to the inlet duct for supplying raw gas thereto, the inlet duct having a closed lower end having a substantially conical shape.
2. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 1 including a rotationally symmetrical elongated flow body located within the inlet duct and extending along the axis thereof.
3. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 2 wherein the substantially conical closed lower end of the inlet duct merges with said flow body.
4. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 1 wherein said raw gas supply tube is disposed in a plane perpendicular to the axis of the inlet duct.
5. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 1 wherein said gas supply tube is connected to the inlet duct at an angle to the axis of the inlet duct and substantially parallel to the incline of the substantially conical closed lower end thereof.
6. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 1 including at least two gas supply tubes extending parallel to and adjacent one another, one of said gas supply tubes being located radially outwardly from the other and partly surrounding the inlet duct, said one gas supply tube communicating with the interior of the inlet duct at a location offset 90° from a location at which the other gas supply tube communicates with the interior of the inlet duct.
7. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 1 including an annular diaphragm mounted on the outside of the inlet duct above said raw gas supply tube.
8. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 7 including nozzles for supplying additional air provided in the wall of the inlet duct above said annular diaphragm, said nozzles being disposed tangentially to the inlet duct wall and being inclined to the direction of flow of the raw gas within the inlet duct.
1. In a tornado flow separator including a cylindrical vortex chamber defined by a cylindrical chamber wall, an inlet duct for raw gas to be purified in the separator disposed within and coaxial with the chamber at one end thereof, an outlet for gas purified in the separator located at the other end of the chamber, auxiliary gas supply inlets extending tangentially to the chamber wall in the vicinity of the purified gas outlet and being inclined with respect to the chamber wall so as to supply a flow of auxiliary gas to the chamber opposite in direction to the flow of raw gas therein, and means defining an annular discharge gap coaxially surrounding the raw gas inlet duct for discharging from the chamber particles separated from the raw gas supplied thereto, a device for applying a twist to the raw gas supplied to the separator comprising at least one raw gas supply tube connected tangentially to the inlet duct for supplying raw gas thereto, the inlet duct having a closed lower end having a substantially conical shape.
2. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 1 including a rotationally symmetrical elongated flow body located within the inlet duct and extending along the axis thereof.
3. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 2 wherein the substantially conical closed lower end of the inlet duct merges with said flow body.
4. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 1 wherein said raw gas supply tube is disposed in a plane perpendicular to the axis of the inlet duct.
5. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 1 wherein said gas supply tube is connected to the inlet duct at an angle to the axis of the inlet duct and substantially parallel to the incline of the substantially conical closed lower end thereof.
6. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 1 including at least two gas supply tubes extending parallel to and adjacent one another, one of said gas supply tubes being located radially outwardly from the other and partly surrounding the inlet duct, said one gas supply tube communicating with the interior of the inlet duct at a location offset 90° from a location at which the other gas supply tube communicates with the interior of the inlet duct.
7. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 1 including an annular diaphragm mounted on the outside of the inlet duct above said raw gas supply tube.
8. Device for applying a twist to raw gas supplied to a tornado flow separator according to claim 7 including nozzles for supplying additional air provided in the wall of the inlet duct above said annular diaphragm, said nozzles being disposed tangentially to the inlet duct wall and being inclined to the direction of flow of the raw gas within the inlet duct.
Description:
The invention relates to device for producing a twist in raw gas which is supplied into a tornado flow generator or separator to be purified therein. Such tornado flow generators are usually employed for separating solid or liquid particles from gases, particularly for the removal of dust, and are formed of a cylindrical vortex chamber having a coaxial inlet duct therein for the raw gas that is located at one end of the vortex chamber and a coaxial outlet for the gas, that has been purified, located at the other end of the vortex chamber. The tornado flow generator also is provided with auxiliary gas inlets disposed in the housing or wall of the vortex chamber at an inclination and opposite to the flow direction of the incoming raw gas so as to produce a tornado flow. 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 U.S. Pat. No. 3,199,268 to Oehlrich et al. and in U.S. 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 flow and an inside 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.
In the known tornado flow generators or separators of this general type, the tornado flow is produced on the one hand, by auxiliary gas flowing through the inlet therefor that extends tangentially to the wall or housing of the vortex chamber, and, on the other hand, by imparting a twist to the raw gas flow within the inlet duct to which it is supplied. It has been known heretofore to provide a twist-imparting device for producing a twist in the raw gas flow. This known device is formed of spherically arched guide vanes, which extend radially outwardly from an axial flow body or streamlined guide member located in the raw gas inlet duct. Such guide vanes have been found to be unsuitable for specific types of dust and particularly for separating or extracting dust of a useful nature because the contact of such useful dust with the guide vanes causes an alteration in the grain structure of the dust, especially when the dust impinges upon the leading edges of the guide vanes. Moreover, there is a danger that certain types of dust will adhere to or cake on such twist devices.
It is accordingly an object of the invention to provide a device for imparting a twist to a tornado flow generator, which dispenses with disruptive inserts or built-in components, and is nevertheless capable of providing the incoming raw gas with an adequate twist.
With the foregoing and other objects in view, there is provided in accordance with the invention, in a tornado flow separator including a cylindrical vortex chamber defined by a cylindrical chamber wall, an inlet duct for raw gas to be purified in the separator disposed within and coaxially with the chamber at one end thereof, an outlet for gas purified in the separator located at the other end of the chamber, auxiliary gas supply inlets extending tangentially to the chamber wall in the vicinity of the purified gas outlet and being inclined with respect to the chamber wall so as to supply a flow of auxiliary gas to the chamber opposite in direction to the flow of the raw gas therein, and means defining an annular discharge gap coaxially surrounding the raw gas inlet duct for discharging from the chamber particles separated from the raw gas supplied thereto, at least one raw gas supply to be connected tangentially to the inlet duct for supplying raw gas thereto, the inlet duct having a closed lower end having a substantially conical shape.
By tangentially connecting the raw gas supply tube to the raw gas inlet duct, the supplied raw gas flow is provided with an adequate twist due to the fact that the raw gas flow is caused to rotate along the circular inner wall of the inlet duct and emerges into the vortex chamber proper in the form of a rotational flow. The substantially conical shape of the lower closed end or base of the inlet duct simultaneously facilitates the deflection of the raw gas flow so that an axial component is applied to the raw gas flow in addition to a circulatory component.
In order to improve the guidance of the developing rotational flow, there is provided, in accordance with another feature of the invention, a rotationally symmetrical elongated flow body within the raw gas inlet duct and extending along the axis thereof. The substantially conical end of the inlet duct merges directly with the flow body.
In accordance with a further feature of the invention, the gas supply tube is disposed in a plane that is perpendicular to the axis of the raw gas inlet or is connected to the inlet duct at an angle to the axis of the inlet duct and substantially parallel to the incline of the substantially conical end of the inlet duct.
It is also expedient and in accordance with an added feature of the invention to provide a plurality of supply tubes for the raw gas communicating with the inlet duct at different sides thereof. It is also feasible, in accordance with the invention, to provide at least two as supply tubes which extend parallel to and adjacent one another, one of the gas supply tubes being located radially outwardly from the other and partly surrounding the raw gas inlet duct, the one gas supply tube communicating with the interior of the inlet duct at a location offset 90° from the location at which the other gas supply tube communicates with the interior of the inlet duct.
In order to shield the annular discharge gap against an excessive volume of flow medium, there is provided, in accordance with an additional feature of the invention, an annular diaphragm on the outside of the inlet duct, above the supply tubes for the raw gas.
In accordance with yet another feature of the invention, to avoid caking on the inner wall of the gas duct of particles separated from the raw gas, nozzles for supplying additional air are provided in the inlet duct wall above the annular diaphragm, the nozzles being disposed tangentially to the cylindrical inlet duct wall and being inclined to the direction of flow of the raw gas within the inlet duct. An air film or layer is thereby formed on the inner wall surface of the inlet duct so as to prevent the size or shape of the particles from becoming altered due to contact thereof with the wall surface, a feature which is of particular importance, as aforementioned, with respect to dusts or powders which provide a useful purpose.
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 device for imparting a twist to a flow of raw gas in a tornado flow separator, 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 specific embodiments when read in connection with the accompanying drawing, in which:
FIG. 1a is a diagrammatic longitudinal sectional view of a tornado flow generator or separator provided with a flow body and with raw gas supply tubes connected tangentially with an inlet duct;
FIG. 1b is a diagrammatic cross-sectional view of FIG. 1a taken along the line IB -- IB in the direction of the arrows;
FIG. 2 is a partial view similar to that of FIG. 1a of another embodiment of the tornado flow separator having vertically inclined raw gas supply tubes and an inlet duct having a closed conical base or end;
FIG. 3a is a diagrammatic longitudinal sectional view similar to part of FIG. 1a of yet another embodiment of the tornado flow separator wherein two parallel raw gas inlet tubes are provided which extend tangentially to the inlet duct;
FIG. 3b is a diagrammatic cross-sectional view of FIG. 3a taken along the line IIIB -- IIIB in the direction of the arrows;
FIG. 4a is a view similar to that of FIG. 3a of a further embodiment of the invention showing two additional or supplementary air nozzles provided in the wall of the inlet duct;
FIG. 4b is a diagrammatic cross-sectional view of FIG. 4a taken along the line IVB -- IVB in the direction of the arrows.
Referring now to the drawings and first, particularly, to FIGS. 1a and 1b thereof, there is shown a tornado flow generator or separator having a cylindrical vortex chamber 1 in which an inlet duct 2 of smaller diameter is disposed coaxially therewith at a lower region thereof, as viewed in FIG. 1. An outlet 3 for gas purified in the tornado flow separator is located at an opposite end of the vortex chamber 1. Moreover, in an upper region of the vortex chamber 1, as viewed in FIG. 1, auxiliary or secondary air supply nozzles 4 are provided extending tangentially to the cylindrical wall of the vortex chamber 1 and inclined so as to direct the auxiliary air flow in a direction opposite to the direction of flow of the raw gas supplied to the vortex chamber 1 through the inlet duct 2 and so as to produce a radially outer circulatory flow. The auxiliary air supply nozzles 4 are supplied with auxiliary air from a common surrounding chamber 5 and a supply line 6.
In accordance with the invention, the inlet duct 2 has a closed lower end or base 7 and, as seen more clearly in FIG. 1b, is provided with two raw gas supply tubes 8 and 9 which extend tangentially to the wall of the inlet duct 2 and communicate through respective openings 10 and 11 with the interior of the inlet duct 2. A twist is thereby applied to the incoming flow of raw gas due to the deflection thereof at the inner wall surface of the inlet duct 2 and, furthermore, due to the substantially conical surface 12 of the closed base 7 an axial component is applied to the raw gas flow. To stabilize the position of the resulting rotational flow 13, a rotationally symmetrical elongated flow body or streamlined guide member 14 is disposed along the axis of the inlet duct 2, the lower part of the flow body 14 merging or joining directly with the conical end or base 12.
The mode of operation of the tornado flow generator of the invention as shown in FIGS. 1a and 1b is as follows:
The raw gas which flows tangentially through supply tubes 8 and 9 into the inlet duct 2, is caused to rotate and is deflected in upward direction. The raw gas then traverses the vortex chamber 1 in the form of a rotational flow 13. A vortex source is produced above the mouth of the raw gas inlet duct 2, which greatly aids in the precipitation or separation of the solid or liquid particles, as the case may be, that are contained or entrained in the raw gas flow. In this vortex source, the particles that are to be separated are driven radially outwardly not only due to the action of centrifugal force, but also the radial components of the drag forces of the gas flow additionally act thereon in radially outward direction, i.e., in the same direction as that in which the centrifugal force acts. The removal of very small or light particles is thereby facilitated so that tornado flow generators or separators of the afore-described type are of particular importance for separating dusts in the fine and very fine ranges below 5μ diameter.
The secondary air which is supplied through the auxiliary gas supply nozzles 4 produces circulatory flow 15 that travels substantially helically downwardly in a region adjacent the wall of the vortex chamber 1. The particles hurled radially outwardly from the inner rotational flow 13 are captured by the circulatory flow 15 and carried downwardly through an annular gap or slot 17, defined by a diaphragm 16 located on the outside of the inlet duct 2 and by the inner surface of the vortex chamber wall 1, into a partially illustrated bin or bunker 18. Part of the descending flow 15 branches off, at an approximate location 19, from the branch 20 thereof which flows into the bin 18 and is deflected above the raw gas inlet duct 2 toward the axis of the vortex chamber 1, so as to form a vortex sink. The branched-off portion of the circulatory flow there joins the upwardly traveling rotational flow 13, thereby also increasing the twist of the inner rotational flow 13.
In FIG. 2 there is shown another embodiment of the raw gas inlet or supply to the tornado flow separator according to the invention. In this embodiment, the lower base of the inlet duct 2 is shaped as a cone 12. The raw gas supply tubes 21 extend diagonally from below into the inlet duct 2, i.e., substantially in parallel with the incline of the conical surface 12, an axial force component being applied to the resulting rotational flow merely due to the inclination of the raw gas supply tube 21, alone.
According to FIGS. 1a and 1b, the gas inlets 8 and 9 communicate with the inlet duct from different sides thereof. This necessitates a rather complex branching of the supply upstream of the tornado flow generator. It is consequently also possible, as illustrated in FIGS. 3a and 3b to divide the raw gas into two parallel supply tubes 22 and 23 at the entry thereof into the inlet duct 2, the radially inner supply tube 22 communicating with the inlet duct 2, in the given manner of the tubes 8 and 9 of FIG. 1b, through an opening 24, while the radially outer supply tube 23 first extends on the outside portion of the periphery of the inlet duct 2 and communicates with the inlet duct 2 at a supply location 25, which is offset by at least 90° from the supply opening 240. Introduction of raw gas from different sides into the inlet duct 2 offers the advantage that a more uniform vortex is developed in the inlet duct 2 and in the vortex chamber 1 than would have been developed if only 25, one supply tube would have communicated at one location with the inlet duct 2.
In order to prevent adhesive particles from becoming fixed to the inner wall surface of the inlet duct 2, it is possible to produce an additional air film at the inner wall surface. To this end, additional or supplementary tangential nozzles 26 and 27, upwardly inclined in the flow direction of the raw gas, are disposed, as shown in FIG. 4 above the diaphragm 16. These nozzles 26 and 27 are supplied with supplemental air from an additional annular chamber 28. In the vicinity of the wall surface of the inlet duct 2, another helically traveling flow 29 is thus formed which encloses or surrounds the inner gas flow 13, thereby preventing the particles from adhering to the inner wall surface of the inlet duct 2.
With the aforedisclosed construction of the inlet duct 2 and the tangential supply tubes for the raw gas, trouble-free twisting of the raw gas is effected, and the particles contained therein do not alter their grain structure or adhere to obstructing inserts, such as conventional baffle plates. By varying the number of the raw gas supply tubes and their angles of inclination relative to the inlet duct 2, the magnitude of the twist applied to the raw gas flow is variable within broad ranges.
The tornado flow itself is formed of an outer, substantially helical potential circulatory flow and an inside 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.
In the known tornado flow generators or separators of this general type, the tornado flow is produced on the one hand, by auxiliary gas flowing through the inlet therefor that extends tangentially to the wall or housing of the vortex chamber, and, on the other hand, by imparting a twist to the raw gas flow within the inlet duct to which it is supplied. It has been known heretofore to provide a twist-imparting device for producing a twist in the raw gas flow. This known device is formed of spherically arched guide vanes, which extend radially outwardly from an axial flow body or streamlined guide member located in the raw gas inlet duct. Such guide vanes have been found to be unsuitable for specific types of dust and particularly for separating or extracting dust of a useful nature because the contact of such useful dust with the guide vanes causes an alteration in the grain structure of the dust, especially when the dust impinges upon the leading edges of the guide vanes. Moreover, there is a danger that certain types of dust will adhere to or cake on such twist devices.
It is accordingly an object of the invention to provide a device for imparting a twist to a tornado flow generator, which dispenses with disruptive inserts or built-in components, and is nevertheless capable of providing the incoming raw gas with an adequate twist.
With the foregoing and other objects in view, there is provided in accordance with the invention, in a tornado flow separator including a cylindrical vortex chamber defined by a cylindrical chamber wall, an inlet duct for raw gas to be purified in the separator disposed within and coaxially with the chamber at one end thereof, an outlet for gas purified in the separator located at the other end of the chamber, auxiliary gas supply inlets extending tangentially to the chamber wall in the vicinity of the purified gas outlet and being inclined with respect to the chamber wall so as to supply a flow of auxiliary gas to the chamber opposite in direction to the flow of the raw gas therein, and means defining an annular discharge gap coaxially surrounding the raw gas inlet duct for discharging from the chamber particles separated from the raw gas supplied thereto, at least one raw gas supply to be connected tangentially to the inlet duct for supplying raw gas thereto, the inlet duct having a closed lower end having a substantially conical shape.
By tangentially connecting the raw gas supply tube to the raw gas inlet duct, the supplied raw gas flow is provided with an adequate twist due to the fact that the raw gas flow is caused to rotate along the circular inner wall of the inlet duct and emerges into the vortex chamber proper in the form of a rotational flow. The substantially conical shape of the lower closed end or base of the inlet duct simultaneously facilitates the deflection of the raw gas flow so that an axial component is applied to the raw gas flow in addition to a circulatory component.
In order to improve the guidance of the developing rotational flow, there is provided, in accordance with another feature of the invention, a rotationally symmetrical elongated flow body within the raw gas inlet duct and extending along the axis thereof. The substantially conical end of the inlet duct merges directly with the flow body.
In accordance with a further feature of the invention, the gas supply tube is disposed in a plane that is perpendicular to the axis of the raw gas inlet or is connected to the inlet duct at an angle to the axis of the inlet duct and substantially parallel to the incline of the substantially conical end of the inlet duct.
It is also expedient and in accordance with an added feature of the invention to provide a plurality of supply tubes for the raw gas communicating with the inlet duct at different sides thereof. It is also feasible, in accordance with the invention, to provide at least two as supply tubes which extend parallel to and adjacent one another, one of the gas supply tubes being located radially outwardly from the other and partly surrounding the raw gas inlet duct, the one gas supply tube communicating with the interior of the inlet duct at a location offset 90° from the location at which the other gas supply tube communicates with the interior of the inlet duct.
In order to shield the annular discharge gap against an excessive volume of flow medium, there is provided, in accordance with an additional feature of the invention, an annular diaphragm on the outside of the inlet duct, above the supply tubes for the raw gas.
In accordance with yet another feature of the invention, to avoid caking on the inner wall of the gas duct of particles separated from the raw gas, nozzles for supplying additional air are provided in the inlet duct wall above the annular diaphragm, the nozzles being disposed tangentially to the cylindrical inlet duct wall and being inclined to the direction of flow of the raw gas within the inlet duct. An air film or layer is thereby formed on the inner wall surface of the inlet duct so as to prevent the size or shape of the particles from becoming altered due to contact thereof with the wall surface, a feature which is of particular importance, as aforementioned, with respect to dusts or powders which provide a useful purpose.
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 device for imparting a twist to a flow of raw gas in a tornado flow separator, 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 specific embodiments when read in connection with the accompanying drawing, in which:
FIG. 1a is a diagrammatic longitudinal sectional view of a tornado flow generator or separator provided with a flow body and with raw gas supply tubes connected tangentially with an inlet duct;
FIG. 1b is a diagrammatic cross-sectional view of FIG. 1a taken along the line IB -- IB in the direction of the arrows;
FIG. 2 is a partial view similar to that of FIG. 1a of another embodiment of the tornado flow separator having vertically inclined raw gas supply tubes and an inlet duct having a closed conical base or end;
FIG. 3a is a diagrammatic longitudinal sectional view similar to part of FIG. 1a of yet another embodiment of the tornado flow separator wherein two parallel raw gas inlet tubes are provided which extend tangentially to the inlet duct;
FIG. 3b is a diagrammatic cross-sectional view of FIG. 3a taken along the line IIIB -- IIIB in the direction of the arrows;
FIG. 4a is a view similar to that of FIG. 3a of a further embodiment of the invention showing two additional or supplementary air nozzles provided in the wall of the inlet duct;
FIG. 4b is a diagrammatic cross-sectional view of FIG. 4a taken along the line IVB -- IVB in the direction of the arrows.
Referring now to the drawings and first, particularly, to FIGS. 1a and 1b thereof, there is shown a tornado flow generator or separator having a cylindrical vortex chamber 1 in which an inlet duct 2 of smaller diameter is disposed coaxially therewith at a lower region thereof, as viewed in FIG. 1. An outlet 3 for gas purified in the tornado flow separator is located at an opposite end of the vortex chamber 1. Moreover, in an upper region of the vortex chamber 1, as viewed in FIG. 1, auxiliary or secondary air supply nozzles 4 are provided extending tangentially to the cylindrical wall of the vortex chamber 1 and inclined so as to direct the auxiliary air flow in a direction opposite to the direction of flow of the raw gas supplied to the vortex chamber 1 through the inlet duct 2 and so as to produce a radially outer circulatory flow. The auxiliary air supply nozzles 4 are supplied with auxiliary air from a common surrounding chamber 5 and a supply line 6.
In accordance with the invention, the inlet duct 2 has a closed lower end or base 7 and, as seen more clearly in FIG. 1b, is provided with two raw gas supply tubes 8 and 9 which extend tangentially to the wall of the inlet duct 2 and communicate through respective openings 10 and 11 with the interior of the inlet duct 2. A twist is thereby applied to the incoming flow of raw gas due to the deflection thereof at the inner wall surface of the inlet duct 2 and, furthermore, due to the substantially conical surface 12 of the closed base 7 an axial component is applied to the raw gas flow. To stabilize the position of the resulting rotational flow 13, a rotationally symmetrical elongated flow body or streamlined guide member 14 is disposed along the axis of the inlet duct 2, the lower part of the flow body 14 merging or joining directly with the conical end or base 12.
The mode of operation of the tornado flow generator of the invention as shown in FIGS. 1a and 1b is as follows:
The raw gas which flows tangentially through supply tubes 8 and 9 into the inlet duct 2, is caused to rotate and is deflected in upward direction. The raw gas then traverses the vortex chamber 1 in the form of a rotational flow 13. A vortex source is produced above the mouth of the raw gas inlet duct 2, which greatly aids in the precipitation or separation of the solid or liquid particles, as the case may be, that are contained or entrained in the raw gas flow. In this vortex source, the particles that are to be separated are driven radially outwardly not only due to the action of centrifugal force, but also the radial components of the drag forces of the gas flow additionally act thereon in radially outward direction, i.e., in the same direction as that in which the centrifugal force acts. The removal of very small or light particles is thereby facilitated so that tornado flow generators or separators of the afore-described type are of particular importance for separating dusts in the fine and very fine ranges below 5μ diameter.
The secondary air which is supplied through the auxiliary gas supply nozzles 4 produces circulatory flow 15 that travels substantially helically downwardly in a region adjacent the wall of the vortex chamber 1. The particles hurled radially outwardly from the inner rotational flow 13 are captured by the circulatory flow 15 and carried downwardly through an annular gap or slot 17, defined by a diaphragm 16 located on the outside of the inlet duct 2 and by the inner surface of the vortex chamber wall 1, into a partially illustrated bin or bunker 18. Part of the descending flow 15 branches off, at an approximate location 19, from the branch 20 thereof which flows into the bin 18 and is deflected above the raw gas inlet duct 2 toward the axis of the vortex chamber 1, so as to form a vortex sink. The branched-off portion of the circulatory flow there joins the upwardly traveling rotational flow 13, thereby also increasing the twist of the inner rotational flow 13.
In FIG. 2 there is shown another embodiment of the raw gas inlet or supply to the tornado flow separator according to the invention. In this embodiment, the lower base of the inlet duct 2 is shaped as a cone 12. The raw gas supply tubes 21 extend diagonally from below into the inlet duct 2, i.e., substantially in parallel with the incline of the conical surface 12, an axial force component being applied to the resulting rotational flow merely due to the inclination of the raw gas supply tube 21, alone.
According to FIGS. 1a and 1b, the gas inlets 8 and 9 communicate with the inlet duct from different sides thereof. This necessitates a rather complex branching of the supply upstream of the tornado flow generator. It is consequently also possible, as illustrated in FIGS. 3a and 3b to divide the raw gas into two parallel supply tubes 22 and 23 at the entry thereof into the inlet duct 2, the radially inner supply tube 22 communicating with the inlet duct 2, in the given manner of the tubes 8 and 9 of FIG. 1b, through an opening 24, while the radially outer supply tube 23 first extends on the outside portion of the periphery of the inlet duct 2 and communicates with the inlet duct 2 at a supply location 25, which is offset by at least 90° from the supply opening 240. Introduction of raw gas from different sides into the inlet duct 2 offers the advantage that a more uniform vortex is developed in the inlet duct 2 and in the vortex chamber 1 than would have been developed if only 25, one supply tube would have communicated at one location with the inlet duct 2.
In order to prevent adhesive particles from becoming fixed to the inner wall surface of the inlet duct 2, it is possible to produce an additional air film at the inner wall surface. To this end, additional or supplementary tangential nozzles 26 and 27, upwardly inclined in the flow direction of the raw gas, are disposed, as shown in FIG. 4 above the diaphragm 16. These nozzles 26 and 27 are supplied with supplemental air from an additional annular chamber 28. In the vicinity of the wall surface of the inlet duct 2, another helically traveling flow 29 is thus formed which encloses or surrounds the inner gas flow 13, thereby preventing the particles from adhering to the inner wall surface of the inlet duct 2.
With the aforedisclosed construction of the inlet duct 2 and the tangential supply tubes for the raw gas, trouble-free twisting of the raw gas is effected, and the particles contained therein do not alter their grain structure or adhere to obstructing inserts, such as conventional baffle plates. By varying the number of the raw gas supply tubes and their angles of inclination relative to the inlet duct 2, the magnitude of the twist applied to the raw gas flow is variable within broad ranges.