US3389793A

US3389793A - Cyclone washer with water only

Info

Publication number: US3389793A
Application number: US630364A
Authority: US
Inventors: Jan N J Leeman
Original assignee: Stamicarbon BV
Current assignee: Stamicarbon BV
Priority date: 1967-04-12
Filing date: 1967-04-12
Publication date: 1968-06-25
Anticipated expiration: 1985-06-25
Also published as: SE342153B; FR1558236A; DE6606546U; GB1168218A; OA02794A; ES352386A1

Description

June 25, 1968 J. N. J. LEEMAN CYCLONE WASHER WITH WATER ONLY Filed April 12, 1967 United States Patent 3,389,793 CYCLONE WASHER WHTH WATER ONLY Jan N. .1. Leeman, Heerlen, Netherlands, assigner to Starnicarhon NN., Heerlen, Netherlands Filed Apr. 12, 1967, Ser. No. 630,364 Claims. (Cl. 209-211) ABSTRACT 0F THE BISCLSURE A hydrocyclone for separating particles of Idifferent specific gravity having a cylindrical portion merging with an intermediate annular portion, which in turn merges with a frusto conical portion, the included apex angle of which lies between 50 and 90. The narrow end of the frusto conical portion of the hydrocyclone merges with a concave portion which terminates in an orifice outlet.

This invention relates to the separation of solids of different specific gravity and particle size into fractions one of which contains predominantly heavy particles while another fraction contains predominantly light particles. More particularly this invention relates to a hy- `drocyclone particularly suited to effect such separation.

A hydrocyclone usually consists of a vessel bounded by a closed surface of revolution and provided with one or more feed ducts leading tangentially into the vessel and With two opposite discharge openings, namely the apex and overflow openings, which are centrally arranged, The edge of the overflow opening may be extended into the vessel and may have the shape of a short tubular member, hereinafter called vortex fin-der.

The invention can be used to advantage in the separation of iron ores into a fraction consisting mainly of iron ore particles and a fraction consisting mainly of gangue particles. The invention can also be used to advantage in the separation of a mixture of coal and shale particles into a fraction with low ash content Which fraction mainly consists of coal and a fraction with a high ash content which latter fraction is chiefly composed of shale particles. The invention is particularly advantageous in that the separation medium used in water only, thus substantially eliminating the need of providing extraneous materials to adjust the specific gravity of the separation medium.

The separating medium and solid particles are injected tangentially into the cyclone. Two vortices are produced turning in the same direction, but possessing opposite axial movements. Under the centrifugal force in the vortices which will normally be much greater than the force of gravity the solid particles are separated according to specific gravity into two fractions which leave the cyclone through the said opposite openings.

The use of cyclones for separation of particles of difiering specific gravity has achieved great commercial success. It has many advantages, such as very high capacity in a small space, ability to handle fine fragmentary materials, and the like. With some ores, however, the sharpness of separation is not always perfect. For example, with iron ores in which the gangue may be silica, such as quartz, it is of utmost importance to obtain an iron ore concentrate containing a minimum amount of silica in order to meet the needs of blast furnaces. The object of the present invention is to provide a cyclone with an irnproved form of vortex chamber which greatly raises the efficiency of the separating action in the case of particles of different grain size and specific gravity. To this end the hydrocyclone of this invention comprises a vessel, `a vortex finder axially arranged within said vessel, said vessel having a cyclone chamber therein, said chamber being confined 'by a cylindrical portion which (a) surrounds said vortex finder, (b) has at last one inlet lead- Patented .lune 25, 1968 ing tangentially into said chamber, (c) merges at one end thereof with an overflow portion having an outlet in communication with said vortex finder, and (d) merges at the other end thereof with a frusto conical portion which has an included angle of at least and not exceeding 90, and merges with a concave portion at the narrow end thereof. The concave portion terminates in an outlet orifice.

An illustrative embodiment of the invention is shown in the accompanying drawing wherein the hydrocyclone vessel 10 defining a cyclone chamber 12 comprises a cylindrical portion 14 which merges with a frusto conical portion 18. The narrow end of the frusto conical portion surmounts a concave portion 20 which terminates in an outlet orifice 22. Within the vessel 10 there is provided a vortex lnder 24 which is surrounded by the cylindrical portion 14 and the extension of which is in communication at one end 26 with a discharge outlet 28 provided in the overflow cap 16. The discharge outlet 28 is fitted with a connecting flange 40. The feed pipe 30 which is in tangential relation to the cyclone chamber 12 debouches into the cylindrical portion 14. This feed pipe is fitted with a connecting flange 32.

The cylindrical portion 14, the overflow cap 16, the frusto conical portion 18 and the concave portion 20 can be assembled in any convenient manner to provide the hydrocyclone of this invention. For instance, adjacent one end of the cylindrical portion 14 about the outside peripheral surface thereof there can be provided a plurality of spaced, apertured flange members or ears 34. Removably received within each of the apertured ears 34 is a bolt 36 which is also received Within corresponding holes provided in a ring 38 adapted to lit over the overflow cap 16. The underside of the ring 38 engages a radial llange 42 provided adjacent the open end of the overflow cap 16 at the oatside peripheral surface thereof. A nut 44 threadedly engages the threaded portion of each of the bolt means 36 to secure the cylindrical portion 14 to the overflow cap 16.

The tubular vortex finder 24 can be provided about the outside peripheral surface thereof with -a radial flange 46 provided on one surface adjacent the periphery thereof with a groove 48 and is flat on the opposed surface. The groove 48 receives a corresponding joint 52 placed between the flat surface of the radial flange 42 of the overflow cap 16 and the flange 46. A similar joint 50 is placed in a corresponding groove 54 in the cylindrical portion 14. With this arrangement vortex finders of various axial lengths can easily be inserted and replaced Within the cyclone chamber of the hydrocyclone' of this invention.

Adjacent the other end of the cylindrical portion 14 at the outside peripheral surface thereof is a radial flange member 56 provided with a plurality of holes 53 to receive bolts 60 which in turn are received in corresponding holes 62 provided in a radial flange 64 which is disposed adjacent the wide end of the frusto conical portion 18 at the outside peripheral surface thereof. This arrangement provides for easy interchangeability of frusto conical portions of various heights and shapes.

The nar-row end of the frusto conical portion 18 merges into a concave portion 20, the inner surface 66 of which is dish or bowl-shaped. The concave portion 20 terminates in an outlet 22, the size of which can be easily exchanged by replacement of discharge mouthpiece 68 retainingly held in place by apertured mouthpiece plate 70 which is removably attache-d to the concave portion 2t) by lmeans of lbolts and nuts 72.

A critical feature of the hydrocyclone of this invention is the included apex angle of the frusto conical section18 With the narrow end of this section merging into the concave portion 20. The apex angle lies within the range of 50-90 and amounts to 75 in the embodiment shown. `Further, to enjoy the benefits of this invention certain relative dimensions of the height H of the frusto conical section 18, the inside diameter D of the cylindriA cal portion 14, the length L of the vortex iinder 24 ex tending into the cyclone chamber 12, the maximum di ameter B of the concave portion and the length A of the cylindrical portion 14 sur-rounding the vortex nder 24 should be observed within the following ranges:

These relative dimensions, however, can be varied depending on the particular material being treated in the hydrocyclone of this invention. Thus, it has been found that the particular values of these 4ratios will vary depending on whether the material being separated is coal or iron ore. The treatment of other types of material can affect t-he absolute value of any of the above `relative dimensions. Among the factors controlling the relative dimensions, other than the type of material being separated are the particle size of the material, the concentration of the material in the feed to the hydrocyclone and the separation required. The important consideration is that the frusto conical section has an included apex angle of at least 50 and not exceeding 90, and that the nar- Irow end of this frusto conical section merges with a concave portion which terminates in an outlet orifice.

Example 1 A yhydrocyclone having an included apex angle of 75 and further essentially as shown in the drawing was tested on a lline iron ore feed. The dimensions of the hydrocyelone were as follows:

Mm. Inside diameter of cylindrical portion (D) 350 Length of cylindrical portion (A) 230 Length of vortex finder (L) 250 Inside diameter of vortex nder 150 Height of the frusto conical section (H) 70 Height of concave portion 35 Inside diameter of outlet openin g in concave portion (underflow) Inside diameter of feed inlet opening Feed data and the results obtained were as follows:

The overflow from Example 1 was processed in a second hydrocyclone having essentially the same dimensions as that employed in. Example l. The following results were achieved,

Underow Overflow Capacity (nhs/hn). 1. 3 59. 4 Concentration (g./l.) 898. 0 62. 1 Solids (tons/hr.) 1.1 3. 7

Grain size (mesh): Percent Percent The overliow of Example 2 and the underliow of EX- ample l are the two finished products. The underilow of Example 2 may, if so desired, be used for recirculation.

Example 3 A hydrocyclone made in accordance with this invention and having essentially the same dimensions as the hydrocyclone disclosed in Example 1 but having a cylindrical portion 350 mm. long was employed to separate raw coal having a grain size of from 0.5 to 7 mm. using water as the separation medium. The feed concentration was adjusted to grams of coal per liter; the feed pressure being 1 atmosphere gauge pressure. The separation had the following results:

An underflow fraction was obtained from the outlet opening of the concave section amounting to 17 1n.3/ hour with 8.5 tons of solid matter having an ash content of 58.3%.

The overflow fraction amounted to 108 m.3/hr. with 10.5 tons of solid matter and having an ash content of 8.0%.

Other hydrocyclones, made in accordance with the instant invention and essentially the same as those described in Examples 1 and 3 but having variation in the length L of the vortex finder were also used to separate iron ore or raw coal suspensions with equally favorable results. The lengths of the vortex nder in mm. tested were 100, 120, 150 and 200.

It is not known why concave cyclones result in such marked improvement in the grade of apex concentrate. Obviously, the result is less contamination with light material from the central vortex. It is possible, that the fact that the outer vortex is further out from the center of he cyclone a its apex may result in a more thorough separation near this point because the flow out through the center opening is baied by the concave part. It is, however, quite possible that other features are present and are the most important ones. Therefore, it is not intended to limit the invention to any theory of operation.

It is to be understood that although several preferred embodiments of the invention have been described with considerable particular-ity in the foregoing specication, the invention is not limited to the specic details described but includes all modifications coming within the scope 0f the appended claims and their equivalents.

What is claimed is:

1. A hydrocyclone for separating suspended solids according to specific gravity comprising a vessel, a vortex finder axially arranged within said vessel, said vessel having a cyclone chamber therein, said chamber being confined by a cylindrical portion surrounding said vortex finder, having an inlet leading tangentially into said chamber and merging at one end thereof with an overflow portion having an outlet leading therefrom, said cylindrical portion merging at the other end thereof with a frusto conical portion, said frusto conical portion having an included apex angle of at least 50 and not more than 90 and merging with a concave portion at the narrow end thereof, said concave portion terminating in an outlet orifice.

the length of the cylindrical portion surrounding said vortex nder to the inside diameter of said cylindrical portion is between 0.5-1.5.

3. The hydrocyclone of claim 1 wherein the ratio of the height of said frusto conical section to the inside diameter of said cylindrical portion surrounding said vortex nder is between 0.1-0.6.

4. The hydrocyclone of claim 1 wherein the ratio of the maximum diameter of said concave portion to the inside diameter of the cylindrical portion is between about 0.3-0.9.

5. The hydrocyclone of claim 1 wherein the ratio of the length of the vortex finder to the inside diameter of References Cited UNITED STATES PATENTS 2,573,192 10/1951 Fontein.

2,724,503 11/ 1955 Fontein.

2,783,887 3/ 1957 Chisholm 209--211 2,793,748 5/1957 Herkenhotf.

2,819,795 1/ 1958 Fontein et al.

3,130,157 4/1964 Kelsall et al 210+512 FOREIGN PATENTS 1,037,980 5/ 1963 France.

HARRY B. THORNTON, Primary Examiner.

the intermediate annular portion surrounding said vortex 15 TIM R. MILES, Examiner.

finder is about G25-1.5.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,389,793 Jurl z5, 1968 Jan N. J. Leenan 4 It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as' shown below:

Column l line 45 "used in water @nl n Sh used is waizer on1y,.., Y Ould read Signed and sealed this 18th day of November 1969.

EAL)

[test:

WILLIAM E. SCHUYLER. IRL

lward M. Fletcher, Ir.

Commissioner of Patents nesting Officer