FR2585266A1 - AXIAL FLOW CYCLONE SEPARATION APPARATUS - Google Patents

Abstract

CYCLONAR APPARATUS WITH AXIAL FLOW FOR THE SEPARATION OF PARTICLES IN SUSPENSION IN A FLUID, CONSTITUTED BY A TUBULAR BODY 10 INCLUDING A BLADE 14 FOR ROTATION AT THE END OF ENTRY OF THE FLUID TO BE DEPURED, AN ENERGY RECOVERY DEVICE KINETICS OF THE FLUID AT ITS OTHER END, AND A CORE 12 PROVIDES IN THE AXIS OF THE TUBULAR BODY, LONGITUDINAL SLOTS 18 BEING CUT IN THE WALL OF THE TUBULAR BODY, BETWEEN ITS ENDS, FOR THE EVACUATION OF THE SEPARATED PARTICLES. TO IMPROVE THE SEPARATION EFFICIENCY OF THESE APPLIANCES, ESPECIALLY FOR PARTICLES WHOSE DIMENSIONS ARE BETWEEN 5 AND 10 MICRONS, THE TUBULAR BODY 10 INCLUDES A CONVERGENT UPSTREAM PORTION 10A AND A DIVERGENT DOWNSTREAM PORTION 10C, AND CORE 12 EXTENDS THROUGHOUT THE LENGTH OF THE TUBULAR BODY AND INCLUDES, IN THE DIVERGING PORTION 10C OF THE TUBULAR BODY, A PART 12B WHOSE STRAIGHT SECTION CROSSES FROM UPSTREAM TO DOWNSTREAM.

Description

The subject of the invention is an axial flow cyclone apparatus for

particle separation

  solid or liquid in suspension in a fluid and

  formed by a tubular body comprising a blade for rotating the fluid at the inlet end of the fluid

  to be purified, a device for recovering the energy

  fluid at its other end, and a nucleus

  placed in the axis of the tubular body, longitudinal slots

  Nales being cut in the wall of the tubular body, between its ends, for the evacuation of the separated particles. Devices of this type are generally very effective in separating particles whose size is equal to or greater than 10 microns. On the other hand, for particles of smaller dimensions, their effectiveness

separation is less.

  The object of the present invention is to improve the separation efficiency of these devices, in particular for particles whose dimensions are included

between 5 and 10 microns.

  The cyclone separating apparatus object of the in-

  vention is characterized in that the tubular body

  takes a convergent upstream portion and a divergent downstream portion, considering the flow direction of the fluid, and in that the core extends over substantially the entire length of the tubular body and comprises, in the divergent portion of the tubular body, a portion of which the section

  right rises from upstream to downstream.

  The mechanism for recovering film energy

  The flow of the fluid may comprise, in known manner, straightening vanes. These will be placed either

  the downstream end of the diverging portion of the tubular body

  or between its extremities. In the first case, the tubular body may comprise a cylindrical portion

  downstream of the straightening vanes. Preferably, the

  increasing section of the core will be placed between the former

  upstream tremity of the divergent portion and the - 2 - straightening vanes; the part of the core located downstream of the straightening vanes may be cylindrical or have a section

  right decreasing from upstream to downstream.

  The particle evacuation slots may be provided in the converging portion of the tubular body, near its downstream end, or in a cylindrical portion

  between the convergent and divergent portions.

  The rotational vane of the fluid to be treated may be placed in the convergent portion, near its upstream end, or in a cylindrical portion of the

  tubular body provided upstream of the convergent portion.

  The part of the core extending along the convergent portion of the tubular body may be cylindrical or have a decreasing cross section from upstream to

downstream.

  The arrangements according to the invention make it possible

  the separation efficiency by reducing the thickness

  the peripheral boundary layer at the dust discharge slots and by regulating the velocity profile in the fluid vein, which has the effect of promoting the migration of the particles towards the periphery of the tubular body. They also make it possible to create a form favorable to the collection of dust when several devices of the type described are grouped in a

  caisson. For the same efficiency of separation the invention

  It also reduces the fluid velocity at the rotational vane and, hence, its wear. The acceleration of the rotation in the convergent also considerably improves the separation of the dust while maintaining a moderate level of turbulence thanks to the central core which eliminates the axial and

return currents.

  The following description refers to the drawing of the

  which shows, as a non-limitative example,

  several embodiments of the invention.

3 -

  Figures 1 to 4 of this drawing are views, partly

  partly in elevation and partially in section, of four flow cyclone separators

  axial made according to the invention.

  These devices are constituted by a tubular body of revolution 10 inside which is placed an elongated core 12, with a circular section, which extends over the entire length of the body 10 and whose axis coincides with that

  of the last. The front end of the core 12 is profiled.

  Rotating vanes 14 are provided at the end.

  upstream of the apparatus by o between the fluid to be purified and rectifying vanes 16 are arranged in its downstream part; these blades are also used for centering the

  core in the tubular body of the apparatus.

  In the embodiment of FIG. 1, the body of the apparatus successively comprises, by moving in the direction of flow of the fluid indicated by the arrows, an upstream, frustoconical and convergent portion 10a, a cylindrical intermediate portion lob and a downstream, frustoconical and divergent portion 10c. The portion 12a of the core between the rotating vanes 14 and the plane

  connection of the portions lob and 10c, has a cy-

  lindrique, the portion 12b between this plane and the straightening vanes 16 has a frustoconical shape, its section growing regularly from upstream to downstream, and the portion 12c located downstream of the blades 16 also has a

  cylindrical shape. Longitudinal slots 18 are de-

  cut in the lob portion of the tubular body 10 to

  the evacuation of the separated particles of the fluid.

  In the embodiment of FIG.

  10b has been removed and replaced by an extension of the frustoconical portion 10a in which are formed the slots 18. The shapes of the portion 10c and the core 12

  are the same as in the apparatus of Figure 1.

  In the apparatus of FIG. 3, the tubular body successively comprises, from upstream to downstream, a cylindrical portion -4d, a convergent frustoconical portion 10a,

  a divergent frustoconical portion 10c and a cyanic portion

  10th lndrique. The rotating vanes 14 are

  killed in the portion 10d, the straightening vanes 16 are located at the connection portions 10c and 10e and the slots 18 are formed in the downstream portion of the portion 10a. The core 12 has a cylindrical shape between the blades 14 and the connection plane of the portions 10a and 10c (part 12a), a frustoconical shape, with increasing section, in the portion O10c (part 12b) and a frustoconical shape, with a decreasing section , in the 10th portion

(part 12c ').

  In the embodiment of FIG. 4, the body of the apparatus comprises successively a short

  , cylindrical portion 10d, a convergent frustoconical portion

  10a, a cylindrical portion 10b, a truncated portion

  divergent conical 10c and a cylindrical portion 10e.

  The blades 14 are arranged in the portion 10d, immediately

  diatement upstream of the connection plane portions O10a and 10d, the vanes 16 are placed in the portion

  cylindrical 10th, immediately downstream of the connection plane

  portions 10c and 10e and the slots 18 are

  provided in the downstream portion of the cylindrical portion lob.

  The portion 12a 'of the core between the blades 14 and the connection plane of the portions 10a and lob of the body

  of the apparatus has a frustoconical shape, with a decreasing section

  Part 12a "situated in the portion 10b has a cylindrical shape, the portion 12b located in the portion 10c has a frustoconical shape, with increasing cross section and the portion 12c 'located downstream of the righting vanes 16 has a frustoconical shape, This unit will be used in the case of difficult separations because

  it allows, thanks to the narrowing of the nucleus in the por-

  10a and 10b, to obtain centrifugal acceleration

  superior for the same radial size of the device.

  -5- The particular design of these devices allows to create a high centrifugal force in the area of

  slots 16 with a relatively low pressure drop.

  Moreover, the arrangement of the slots 16 in a narrow portion of the body of the apparatus facilitates the exit of the particles and their collection when several devices

  are arranged side by side in a box.

  In the downstream part of the apparatus, the truncated form

  Part 12b of the core allows maximum recovery of the kinetic energy of the fluid and, consequently, a significant reduction of the pressure drop. The angel at the top of the frustoconical part 12b of the core may be equal to or greater than that of the O10c portion of the tubular body, but in all cases the cross section of the

  passage formed between them from upstream to downstream.

258S266

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Claims (13)

REVEND I C A T I ONS   1. Axial flow cyclone apparatus for the separation of particles suspended in a fluid, constituted by a tubular body (10) comprising a vane (14) of   rotating at the inlet end of the fluid   rer, a device for recovering the kinetic energy of the fluid at its other end, and a myau (12) disposed in the axis of the tubular body, longitudinal slots (18) being cut in the wall of the tubular body, between its ends, for discharging separated particles, characterized in that the tubular body (10) comprises an upstream -convergent portion (10a) and a divergent downstream portion (10c), and in that the core (12)   extends almost the entire length of the tubular body   and has, in the divergent portion (10c) of the tubular body, a portion (12b) whose cross section grows from upstream to downstream. -   2. Separating apparatus according to claim 1, characterized   characterized in that it comprises rectifying vanes (16) placed at the downstream end of the diverging portion (10c) of the tubular body.   3. Separation apparatus according to claim 2, characterized   characterized in that the tubular body (10) comprises a portion   cylindrical (10e) downstream of the straightening vanes (16).   4. Separating apparatus according to claim 1, characterized   in that the straightening vanes (16) are   between the ends of the diverging portion (10c) of the tubular body.   Separating apparatus according to claims 2, 3   or 4, characterized in that the portion (12b) of increasing cross section of the core extends between the upstream end of the divergent portion (10c) of the tubular body and the blades straightening (16).   Separation apparatus according to claim 5, characterized   characterized in that the portion (12c) of the core located downstream   straightening vanes (16) have a cylindrical shape.   Separation apparatus according to claim 5, characterized   characterized in that the portion (12c ') of the core located downstream of the straightening vanes (16) has a frustoconical shape to   decreasing section from upstream to downstream.   8. Separation apparatus according to any one of the   preceding statements, characterized in that the longitudinal slots (18) are formed in the downstream portion of   the convergent portion (10a) of the tubular body.   9. Separation apparatus according to any one of the   1 to 7, characterized in that the longitudinal slots   dinals (18) are formed in a cylindrical portion (lob) of the tubular body lying between the converging portions (10a) and divergent (10c).   10. Separation apparatus according to any one of the   preceding statements, characterized in that the blading of   rotation (14) is placed in the convergent portion   gente (10a) of the tubular body near its upstream end. 11. Separation apparatus according to any one of   Claims 1 to 9, characterized in that the blading   in rotation (14) is placed in a cylindrical portion (1Od) of the tubular body provided upstream of the portion convergent (10a).   12. Separating apparatus according to any one of the   - 8 -, characterized in that the portion (12a ') of the core extending in the convergent portion (10a) of the   tubular body has a truncated conical section with from upstream to downstream.   13. Separating apparatus according to any one of   Claims 1 to 11, characterized in that the portion (12a)   of the core extending in the convergent portion (10a) of   tubular body has a cylindrical shape.