US3396511A - Vortex separator for solid or liquid aerosols or the like - Google Patents

Description

Aug. 13, 1968 A. FRACKE ET AL- VORTEX SEPAHATOR FOR SOLID OR LIQUID AEROSOLS OR THE LIKE Filed March 21, 1966 4 Sheets-Sheet 1 Aug. 13, 1968 A, FRAKE ET AL VORTEX SEPARATOR FOR SOLID OR LIQUID AEROSOLS OR THE LIKE Filed March 21, 1966 4 Sheets-Sheet 2 Aug. 13, 1968 FRACKE ET AL 3,396,511

VORTEX SEPARATOR FOR SOLID OR LIQUID AEROSOL-S OR THE LIKE Filed March 21, 1966 4 Sheets-Sheet 5 Aug. 13, 1968 A. FRACKE ETAL 3,396,511

VORTEX SEPARATOR FOR SOLID 0R LIQUID AEROSOLS OR THE LIKE Filed March 21, 1966 4 Sheets-Sheet 4 United States Patent 3,396,511 VORTEX SEPARATOR FOR SOLID OR LIQUID AEROSOLS OR THE LIKE Aribert Fracke, Heinrich Klein, and Rudolf Pieper, Erlangen, and Eduard Weber, Nurnberg, Germany, assignors to Siemens Aktiengesellschaft, Munich, Germany, a corporation of Germany Filed Mar. 21, 1966, Ser. No. 535,799 Claims priority, application Germany, Mar. 20, 1965, S 96,072 9 Claims. (Cl. 55-83) ABSTRACT OF THE DISCLOSURE Method of increasing the separating action of a vortex separator for solid or liquid particles entrained in a gaseous carrier medium includes supplying particleentrained gaseous carrier medium in an axial direction and in the form of a rotational flow through an inlet located at one end of a rotationally symmetrical vortex chamber; surrounding the rotational flow with a tubularshaped vortex of a gaseous auxiliary medium coaxial with and rotating in the same rotary direction as the rotational flow; discharging the carrier medium through an outlet provided in the other end of the vortex chamber; transforming the tubular-shaped vortex at the outlet of the carrier medium into the circulatory potential flow traveling at a region adjacent the wall of the vortex chamber in a direction opposite to the axial flow direction of the carrier medium and back again at the level of the carrier medium inlet into the tubular-shaped vortex surrounding the rotation flow, so that the auxiliary medium travels in a closed circuit; removing by suction the auxiliary medium in the tubular-shaped vortex flowing in a direction coaxial with that of the carrier medium flow at the level of the outlet for the carrier medium, and resupplying auxiliary medium to the vortex chamber through an annular slot formed at the outlet end thereof.

Apparatus for carrying out the foregoing method includes a rotationally symmetrical vortex chamber having an inlet at one end for supplying particle-entrained gaseous carrier medium in an axial direction and having an outlet at the other end thereof for discharging the carrier medium; means in the inlet creating a rotational flow in the vortex chamber; inlet means extending transversely to the axial direction for supplying a gaseous auxiliary medium to the vortex chamber in the form of a tubular-shaped vortex surrounding the rotational flow, the tubular-shaped vortex being coaxial with and rotating in the same rotary direction as the rotational flow; outlet means extending transversely to the axial direction for discharging the auxiliary medium from the vortext chamber; blower means outside the vortex chamber having its negative pressure side in communication with the auxiliary medium outlet means for removing by suction from the vortex chamber, the auxiliary medium flowing in a direction coaxial to the carrier medium flow axis; the means for supplying auxiliary medium being in communication with the positive pressure side of the blower means for resupplying auxiliary medium to the vortex chamber, whereby the tubular-shaped vortex is transformed at the outlet into the circulatory potential flow traveling in a direction opposite to the axial flow direction of the carrier medium at a region adjacent the wall of the vortex chamber and is transformed back again into the tubular-shaped vortex surrounding the rotational flow at the level of the carrier medium inlet, so that the auxiliary medium travels in a closed circuit.

Our invention relates to method and apparatus for increasing the separating action of a vortex separator for 3,396,51 1 Patented Aug. 13, 1968 solid or liquid particles from aerosols or flows of gaseous medium laden therewith according to the hereinafter described principle.

This 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 separator vessel. The physical principles of this type of separation and the forces resulting from the just-mentioned flow phenomena are explained in Patent No. 3,199,268 to Oehlrich et al. and in the succeeding Patents Nos. 3,199,269 through 3,199,272, which are all assigned to the assignee of the invention in the instant application.

According to the prior disclosures identified above, in vortex separators operating on the tornado-flow principle, a potential circulatory flow is excited and maintained adjacent the walls of a rotationally symmetrical vortex chamber in such a Way that it undergoes a movement in the axial direction of the vortex chamber in addition to the circulatory movement, that axial movement being opposite to the aerosol or dust-laden gas flow flowing axially into one end of the vortex chamber. A component of this potential circulatory flow is diverted toward the axis of the vortex chamber at the level of the aerosol inlet and is transformed together with the aerosol into a co-axial rotational flow circulating in the same direction as the potential circulatory flow within the potential circulatory flow. The particles that are to be separated are passed radially out of the rotational flow, due to the rotation, and into a branch of the potential circulatory flow delivering them into a particle outlet surrounding the aerosol, and from there into a storage chamber, while the purified aerosol discharges from the vortex chamber through a purified-gas outlet at the other end of the vortex chamber. In the known separators employing this tornado flow principle, such as those disclosed .in the aforementioned patents, the potential circulatory flow is produced by the additional supply of a gaseous auxiliary medium which is admitted so that it joins the aerosol flow at an acute angle to the axis of the aerosol flow and in a generally tangential direction to the wall of the vortex chamber.

It has been found, however, that due to wall friction and boundary layer scaling at the vortex chamber wall, a strong inward flow of the gaseous media occurs. Such inward flowsprevent a portion of the particles, which are to be separated, from leaving the rotational flow, and particles which have already been separated are reconveyed to the axial and generally singular flow so that these particles discharge from the vortex chamber through the purified gas outlet.

It is accordingly an object of our invention to provide a method and apparatus for separating solid or liquid particles from aerosols or particle-laden gas flows which will suppress the aforementioned undesirable phenomena and thereby increase the separating efiect of the separator.

With the foregoing and other objects in view we provide, in accordance with the invention, that one end of a rotationally symmetrical vortex chamber, an aerosol or particle-laden gas flow admitted in an axial direction in the form of a rotational flow is surrounded by a coaxial tubular-shaped vortex or vortex tube of an auxiliary gaseous medium circulating in the same direction as that of the rotational flow as well as moving in the same axial direction. At the other end of the vortex chamber, i.e. the end from which the purified aerosol discharges, at a location adjacent the wall of the vortex chamber, the auxiliary gaseous medium with the potential flow circulating in a travel direction opposite to that of the aerosol fiow and at the level of the aerosol inlet once again is transformed into the vortex tube circulating with the rotational flow in such a way that the auxiliary medium is guided in a substantially closed circuit.

A closed circuit of the auxiliary medium can be effected by applying suction to the auxiliary medium flowing coaxially to the aerosol in the form of a vortex tube at the level of the outlet for the purified aerosol and through an annular slot or aperture in the upper portion of the vortex chamber of the separator, an auxiliary medium is newly resupplied thereto. The removal of the auxiliary medium by suction and reintroduction thereof by blowing is effected, in accordance with a further feature of our invention, by an intermediately located blower means.

In accordance with further features of our invention, the auxiliary medium forming the outer potential circulatory flow is removed at the level of the aerosol inlet and is newly resupplied coaxially to the aerosol inlet, both by means of suction.

The invention, however, both as to its construction and method of operation, 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 drawings, in which:

FIG. 1 is a diagrammatic view of a theoretical vortex separator constructed in accordance with the invention;

FIG. 2 is a diagrammatic view of a first practical embodiment of the invention wherein the removal and resupply of the auxiliary medium by suction is eifected at the outlet end of the vortex separator;

FIG. 3 is a diagrammatic view of another embodiment of the vortex separator according to the invention wherein suction removal and resupply of the auxiliary medium is effected at the level of the aerosol inlet; and

FIG. 4 is a diagrammatic view of yet another embodiment of the vortex separator according to the invention wherein a portion of the auxiliary medium is supplied through nozzles located tangential to the walls of the vortex chamber and at an acute angle to the axis of the aerosol flow.

In accordance with the principles disclosed diagrammatically in FIG. 1, the solid or liquid aerosol flows into a vortex chamber 1 through an inlet 2 in the direction of the arrows 4 and is excited for example by means of a pre-twist nozzle 3, provided with suitable vanes in a conventional manner, to form a rotational flow 5 in the direction of the associated arrowheads. This inner coaxial rotational flow 5 is surrounded by a tubular-shaped vortex or vortex tube 8 of a gaseous auxiliary medium. This vortex tube 8 flows, as indicated by the associated arrowheads, in the same direction as the rotational flow 5 through the vortex separator and forms therewith the radially outer limiting region of the rotational flow 5. The auxiliary medium, after being diverted at the level of the aerosol outlet 6, flows in the form, substantially, of a potential circulating flow 9 in a direction opposite to the travel direction of the aerosol toward the aerosol inlet 12, and at the aerosol inlet is again diverted to the rotational flow 8. The path of the auxiliary medium flowing in the circuit is thereby indicated by the reference numeral 10.

The gaseous layer surrounding the aerosol flow 5 thus constitutes a voretx tube with respect to the axial velocity thereof, the axial velocity of the vortex tube portion which is adjacent the aerosol being in the same travel direction as that of the aerosol flow whereas the axial velocity of the portion of the vortex tube located directly at the stationary wall 1 of the vortex chamber has a direction opposite to that of the aerosol flow.

The particles ejected from the main gas flow or aerosol thus pass into the circulating flow 10' of the auxiliary medium and become concentrated therein. Thus, as de scribed in the aforementioned patents disclosing vortex separators constructed in accordance with this tornadoflow principle, the particles are discharged substantially at the reversal point of the potential to rotational flow by a branch of the potential circulatory flow into a collecting chamber 11 surrounding the aerosol inlet 2.

In FIG. 2, there is shown means for removing the auxiliary medium by suction atthe level of the aerosol outlet 6. Thus, the auxiliary medium is evacuated through an annular slot or aperture 15 of the vortex separator 1 and is resupplied by means of a blower 16 through an annular slot or aperture 17. Energy lost due to friction of the auxiliary medium in the vortex separator is replaced by the blower 16. Pro-twisting of the auxiliary medium when readmitted into the vortex chamber is efiected by means of guide vanes or nozzles 13 in the annular slot 17, for supplying the readmitted auxiliary medium in such a way that it joins the aerosol flow in a generally tangential direction and at an acute angle to the axis of the aerosol flow. If desired, the annular slot 17, itself, can have a nozzle-like construction.

In FIG. 3, the removal by suction of the auxiliary medium is eifected by an annular slot 18 in the wall of the vortex chamber at the level of the aerosol inlet 2. By means of a blower 16, which serves for restoring the frictional losses in the vortex chamber, the auxiliary medium is resupplied to the vortex separator through a coaxial annular slot 19 provided in a tubular member directly connected to the aerosol inlet tube 2. Also in this embodiment, as in the embodiment of FIG. 2, suitable conducting vanes or nozzles 13 can be located in the annular slot 19 to provide pre-twisting of the readmitted auxiliary flow medium.

In the embodiment of FIG. 4, a portion of the auxiliary medium removed by suction through the outlet 18 is readmitted through the nozzles 20 joining the aerosol flow in a generally tangential direction and at an acute angle to the axis of the aerosol flow for exciting the potential circulatory flow in the vortex separator.

Due to the vortex tube surrounding the axial aerosol flow, according to the invention, the aforedescribed turbulence and scaling phenomena adjacent the wall of the vortex chamber, are prevented from spreading into the aerosol flow so far as the auxiliary medium, with respect to its rotation, has a greater energy than the aerosol. Since the auxiliary medium, due to the circulatory motion, exhibits no throughput or flow-through, the entire energy content thereof does not enter into the required energy consumption for the aerosol flow proper, but rather, only the energy losses of the auxiliary medium. Consequently, with the instant invention it is possible to provide efliciently an essentially greater rotation of the aerosol flow than is posible, for example, in a conventional cyclone separator.

We claim:

1. Method of increasing the separating action of a vortex separator for solid or liquid particles entrained in a gaseous carrier medium, which comprises supplying particle-entrained gaseous carrier medium in an axial direction and in the form of a rotational fiow through an inlet located at one end of a rotationally symmetrical vortex chamber; surrounding the rotational flow with a tubular-shaped vortex of a gaseous auxiliary medium coaxial with and rotating in the same rotary direction as the rotational flow; discharging the carrier medium through an outlet provided in the other end of the vortex chamber; transforming the tubular-shaped vortex at the outlet of the carrier medium into the circulatory potential flow traveling at a region adjacent the wall of the vortex chamber in a direction opposite to the axial flow direction of the carrier medium and back again at the level of the carrier medium inlet into the tubular-shaped vortex surroundingthe rotational flow, so that the auxiliary medium travels in a closed circuit; removing by suction the auxiliary medium in the tubular-shaped vortex flowing in a direction coaxial with that of the carrier medium flow at the level of the outlet for the carrier medium, and resupplying auxiliary medium to the vortex chamber through an annular slot formed at the outlet end thereof.

2. Method of increasing the separating action of a vortex separator for solid or liquid particles entrained in a gaseous carrier medium, which comprises supplying particle-entrained gaseous carrier medium in an axial direction and in the form of a rotational flow through an inlet located at one end of a rotationally symmetrical vortex chamber; surrounding the rotational flow with a tubular-shaped vortex of a gaseous auxiliary medium coaxial with and rotating in the same rotary direction as the rotational flow; discharging the carrier medium through an outlet provided in the other end of the vortex chamber; transforming the tubular-shaped vortex at the outlet of the carrier medium into the circulatory potential flow traveling at a region adjacent the wall of the vortex chamber in a direction opposite to the axial flow direction of the carrier medium and back again at the level of the carrier medium inlet into the tubularshaped vortex surrounding the rotational flow, so that the auxiliary medium travels in a closed circuit; removing by suction the auxiliary medium forming the radially outer potential circulatory flow at the level of the carrier medium inlet, and resupplying auxiliary medium to the vortex chamber at a location coaxial to and adjacent the carrier medium inlet.

3. Method of increasing the separating action of a vortex separator for solid or liquid particles entrained in a gaseous carrier medium, which comprises supplying particle-entrained gaseous carrier medium in an axial direction and in the form of a rotational flow through an inlet located at one end of a rotationally symmetrical vortex chamber; surrounding the rotation-a1 flow with a tubular-shaped vortex of a gaseous auxiliary medium coaxial with and rotating in the same rotary direction as the rotational flow; discharging the carrier medium through an outlet provided in the other end of the vortex chamber; transforming the tubular-shaped vortex at the outlet of the carrier medium into the circulatory potential flow traveling at a region adjacent the Wall of the vortex chamber in a direction opposite to the axial flow direction of the carrier medium and back again at the level of the carrier medium inlet into the tubular-shaped vortex surrounding the rotational flow, so that the auxiliary medium travels in a closed circuit; removing by suction a portion of the flow of the auxiliary medium from the vortex chamber and resupplying the auxiliary medium to the vortex chamber through at least one inlet in a direction tangential to the wall of the vortex chamber and at an acute "angle to the carrier medium flow axis.

4. Apparatus for increasing the separating action of a vortex separator for solid or liquid particles entrained in a gaseous medium, comprising a rotationally symmetrical vortex chamber having an inlet at one end for supplying particle-entrained gaseous carrier medium in an axial direction and having an outlet at the other end thereof for discharging the carrier medium; means in said inlet creating a rotational flow in said vortex chamber; inlet means extending transversely to said axial direction for supplying a gaseous auxiliary medium to said vortex chamber in the form of a tubular-shaped vortex surrounding said rotational flow, said tubular-shaped vortex being coaxial with and rotating in the same rotary direction as said rotational flow; outlet means extending transversely to said axial direction for discharging the auxiliary medium from said vortex chamber; blower means outside said vortex chamber having its negative pressure side in communication with said auxiliary medium outlet means for removing by suction from said vortex chamber the auxiliary medium flowing in a direction coaxial to the carrier medium flow axis; said means for supplying auxiliary medium being in communication with the positive pressure side of said blower means for resupplying auxiliary medium to said vortex chamber, whereby the tubular-shaped vortex is transformed at said outlet into said circulatory potential fiow traveling in a direction opposite to the axial flow direction of the carrier medium at a region adjacent the wall of said vortex chamber and is transformed back again into said tubular-shaped vortex surrounding said rotational flow at the level of said carrier medium inlet, so that said auxiliary medium travels in a closed circuit.

5. Apparatus according to claim 4, wherein said auxiliary medium outlet means comprises an annular slot coaxial to said carrier medium outlet.

6. Apparatus according to claim 5, wherein said means for supplying auxiliary medium also comprises an annular slot coaxial to said carrier medium outlet and located adjacent the wall of said vortex chamber.

7. Apparatus according to claim 6, wherein both said annular slots surround said carrier medium inlet.

8. Apparatus according to claim 4, wherein said means for supplying auxiliary medium comprises at least one nozzle in the wall of said vortex chamber extending in a direction tangential to the wall of said vortex chamber and at an acute angle to the axial flow direction of the carrier medium.

9. Apparatus according to claim 8, wherein said nozzle is located at the outlet end of said vortex chamber, and said auxiliary medium outlet means is located at said inlet end of said vortex chamber.

References Cited UNITED STATES PATENTS 2,664,966 1/1954 Moore 55456 XR 3,064,411 11/ 1962 Breslove 55457 3,199,270 8/1965 Oehlrich 55-261 RONALD R. WEAVER, Primary Examiner.

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