US2816658A - Hydrocyclones - Google Patents

Description

Dec. 17, 1957 R. T. BRAUN ET AL HYDROCYCLONES 3 Sheets-Sheet 1 Filed Oct. 11; 1954 INVV'ENTORT'; Roberf-T. Bruun Charles A. Sctgreiber ATTORNE Y Dec. 17, 1957 R. T. BRAUN ETAL HYDROCYCLONES 3 Sheets-Sheet 2' Filed Oct. 11. 1954 7 6'8 Overflow Discharge y y ATTORNEY w i Mum Tfh N E 5. WT m mm m C J w: 6 5\ a 1\ III- I 7 2, 2 k 67 44 2 m ,F

Underflow Discharge Dec. 17, 1957 R. T. BRAUN EI'AL HYDROCYCLONES 5 Sheets-Sheet 3 Filed Oct. 11. 1954 l'lilim.

INVENTORS Robert T. Broun Charles A. Schreiber JTTORNEY United States HYDROCYC'LONES Robert T. Braunand- Charles A. Schreiber, Springdale,

Conn, assignors to Dorr-Oliver Incorporated, a corporation of Delaware Application October 11, 1954, Serial No. 461-,532' 7 Claims. (Cl. 209-211)- Thisinvention relates-to hydrocyclones.- More particularly'itrelates to an improved hydrocyclone structure.

One ofthe major problems encountered-in the use of hydrocyclones is-the abrasive wear and chemical break-' down of those surfaces exposed to the action of the moving hydrocyclone contents. As a matter of fact, becauseof thehigh order of magnitude of velocities and centrifugalforces encountered, the useful life of hydrocyclones, depending upon the material of construction and solids being treated, may be relatively short, and has, on

occasion been measurable in hours. Despite attempted remedial measures; including in some instances the provision of sacrificial linings, it has frequently been'found' the configurations of the shell. If the proper criteria'are used in selecting and applying such linings, the useful life of hydrocyclones is appreciably increased. Nevertheless, a se'condary problem must be considered in this regard. It ismanifest that, short of dismantling and visual ex-' amination, there'is'no'practical means for'ascertaining the degree of wear'which has taken place'within an operat-' ing hydr'ocyclone' unit. Consequently, it frequently happened that, despite routine periodic checks, the relatively thin linings wore'through; and since the general con figuration of the cycloneis usuallynot materially altered by thewearing away of even large patchesof such liners,

the" operator often had no way of knowing that the cyclone shell* was no longer protected by the liner. Consequently, it was rather a common occurrence to find thatth'e'cyclone itself had been erodedand corroded entirely awayat points, and the entire unit rendered substantially In order to minimize the expenseand delay incurred as a result of such eventualities, hydro-- useless thereby.

cyclones have, in some'cases, been constructed entirely of flanged sections, adapted to be bolted together to com prise a complete'unit. When one'section is damaged; it is discarded and'replaced, thus avoidingjthe need-for discarding. the entire unit.

, Under normal circumstances, the maximum wear in a Composed of a material which, by reason otitsdegreeof hardness, elasticity, chemicalcharacteristics or etc. tended to resist. wear, these liners are cemented or otherwise bondedto the non-sacrificial shell of the hydrocyclone, and, being" of substantially uniform thickness throughout, followed ice hydrocyclone occurs at the base of the unit in the region of the tangential infiuent wherein the overflow means is also generally disposed, and, to an even greater extent, at the apex in the region of the underfiow means. Con sidering these regions in the order mentioned, it may be observed that the influent region is relatively complex in form since it includes not only a base closure plate with overflow conduit which may pass therethrough, but a tangential feed means opening into the base. Not only is such a section difiicult to line by ordinary lining methods but-the replacement ofsections even in a segmented unit is costly.

With regard to the underflowregion, it is manifestly desirable to provide extra protection in this area of maxirrium wear. In the case of hydrocyclones constructed according to the teachings of the prior art this was difiicult to do since the basic shape of the unit was established by the shape of the shell andthe lining could not be thickened at'any point without effecting the performance of the unit.-

Broadly stated it is the object of this invention to cure each of the shortcomings outlined above, and additionally, to "provide a number of unique functional and structural advantages dealt with in more detail hereinafter.

More specifically, it is a general object of this invention to provide a' hydrocyclone with parts which are not only moreeasily fabricated, but are replaceable at a minimum expenditure of time, eifortand expense.

Itis another general object of this invention to develop" a hydrocyclone with readily removable and replaceable wear resistant liners of a sacrificial material, said liners not necessarily being bonded to the casing.

Anotherobject is to develop a casing for holding these" liners'which can readily be opened for removal and'replacement of liners or liner sections which have become worn;

It-is' a specific object of this invention to develop a hydrocyclone which has a removable and replaceable liner inthe'infeed region of the chamber which not only protects the casing, but also protects the feed conduit and feed inlet ports.

Still'another object of this invention is the development of-a liner adapted to progressively provide more protection' of the casing from the infeed end of the casing to the underfiow discharge end thereof.

The broad concept whereby the foregoing and other objects are attained comprises the utilization of a liner so constructed that its hollow, generally conical interior constitutes the hydrocyclone body'with which the material bei-ng treated-comes in contact, while its outer, generally non-conical surface is incontact with, but not necessarily bonded to, a shell of non-sacrificial material.

For reasons dealt with in more detail hereinafter, in the preferred embodiment the liner comprises a conically' hollowed cylinder. For ease of replacement and modification the'liner is segmented. The preferred embodiment is further characterized by an overflow conduit and an underfiow nozzleconstructed of the same material as the liner.

Before turning to the drawings it should be'noted that as this invention maybe embodied in several forms without departingfrom'the spirit or essential characteristics thereof, the present embodiment is therefore illustrative andnot restrictive; since the scope of-the invention. is defined by the appended claims rather than 'by-"thede;

scription preceding them, and all changes that fall within the metes and bounds of the claims, or of forms that are their functional as well as conjointly cooperative equivalents, are therefore intended to be embraced by those claims.

Referring now to the drawings:

Figure 1 is a perspective view of a practical embodiment of this invention, which view has been partially cutaway to reveal the interior of the hydrocyclone;

Figure 2 is a side sectional view of the hydrocyclone of Figure 1;

Figure 3 is an exploded perspective view of the hollow cylinder sections of sacrificial, wear resistant, material, and of the underflow nozzle section, said exploded view showing portions of the sections cut-away to reveal interior and sectional views;

Figure 4 is an exploded view of the casing into which the various vortex space forming elements of sacrificial, wear resistant material are inserted, and means by which the underflow nozzle section is secured to the hollow cylinder; and V Figure 5 is a cross sectional view taken along the lines 55 of Figure 2.

Referring in somewhat more detail to the drawings, it will be observed that the hydrocyclone comprises an enclosed chamber 12 with a longitudinal axis 14 of radial symmetry so that longitudinally there IS a stationary, smooth, and continuous surface of revolution 13, whereby a vortex space is formed. In the region of one end, the infeed end, of the chamber or vortex space, there is a feed inlet port 16 formed by the tangential and transverse disposition of a feed conduit 18 to and through the surface of revolution. Also at the infeed end of the enclosed chamber 12 there is an overflow outlet 20 which is a tubular orifice aligned with the longitudinal axis of radial symmetry 14. At the opposite end of the chamber, at the radially symmetrical periphery thereof and coaxial with said longitudinal axis of radial symmetry there is an underflow outlet 22.

The surface of revolution 13 is actually the inside periphery of a liner or hollow cylinder 24 composed of a sacrificial, wear resistant material such as, for example, molded rubber, which cylinder has been transversely divided into an infeed section 26, an intermediate section 28, and a lower end section 30. Infeed section 26 has transversely and tangentially disposed to it as an integral part thereof an infeed conduit member 32 which also is composed of a sacrificial, wear resistant material such as, for example, molded rubber, and which forms the feed conduit 18 to chamber 12. It will be observed that the inside diameter of feed conduit 18 has been gradually decreased from a maximum diameter designated as ID; to a minimum diameter ID, in the region of the inlet port 16. The purpose of this is to enable the entrance velocity of the feed slurry introduced into the chamber 12 to reach an optimum velocity and to introduce the feed into the chamber as a stream of optimum diameter.

At the infeed end of the chamber there is a removable orifice plate 36 which has an outside diameter larger than the inside diameter of the end of the chamber adjacent thereto, and in which the overflow outlet 20 is located. This orifice plate 36 is also composed of a sacrificial, wear resistant material such as, for example, molded rubber. In this embodiment the overflow orifice plate comprises a vortex finder member 38 which is integral with the plate.

The remaining portion of the vortex space 12 is formed by the hollow portion of underflow nozzle section 40 which portion has a longitudinal axis of radial symmetry coinciding with the vortex space longitudinal axis 14. Underflow nozzle section 40 is shown as being of a general outwardly cylindrical shape and as being composed of a sacrificial, wear resistant material such as, for example, molded rubber. At the top of the nozzle section 40 there is an outwardly extending flange member 42 for securing the underflow nozzle section to the hollow cylinder 24 and for aligning the axis of said nozzle with the longitudinal axis 14.

Sectionalized hollow cylinder 24 is contained in a casing composed of a non-sacrificial material, which casing comprises a so-called lower housing and a so-called upper housing or head.

In the embodiment shown the lower housing 44 has at the lower end thereof an inwardly extending, annular retaining flange 46 having a downwardly extending annular end member 47 with appropriately spaced, cap screw holes therein. The diameter of the inner circumferential periphery formed by end member 47 should be slightly larger than the outside diameter of the annular flange member 42 of the underflow nozzle section 40. The lougitudinal width of said end member 47 should be the same as or slightly less than the longitudinal width of annular flange member 42. The upper end of the lower housing 44 has a lower, partial conduit housing member 48 which is tangentially and transversely disposed in the same direction to the lower housing 44 as that of the infeed conduit member 32 of the infeed section 26.

Upper housing 50 is comprised of an upper, partial conduit housing member 52 which is disposed tangentially and transversely to the side of the upper housing in the same direction as that of the infeed conduit member 32 to the infeed section 26, and which is adapted to cooperate with the lower partial feed conduit housing member 48 to form a complete housing for the infeed conduit member 32. Upper housing 50 also has an overflow discharge conduit member 54 which is coaxially aligned with the longitudinal axis of radial symmetry 14 for the discharge of overflow passing from the overflow outlet 20.

Underflow nozzle section 40 is secured in place adjacent to the end section 30 of hollow cylinder 24 by means of its upper, annular flange member 42 and a valve holder 56 which is an annular plate with an inside diameter larger than the outside diameter of the annular flange member 42, and an outside diameter here shown to be as large as the outside diameter of end member 47. The valve holder 56, with the underflow nozzle section 40 in place is secured to the housing by means of readily removable cap screws 58 inserted through the valve holder into the appropriate screw holes in the downwardly extending annular end member 47.

The housings are secured together by means of a coupling flange 60 about the upper rim of the lower housing, an adjacent coupling flange 62 about the lower rim of the upper housing, and nut and bolt combinations disposed through each of the appropriately spaced, corresponding bolt holes 63 in the flanges 60 and 62.

For securing the hydrocyclone 10 to the feed supply conduit from a source of hydrostatic head, such as a pump or headbox, the lower portion 48 of the feed conduit housing is supplied with a partial pipe flange 64 while the upper portion 52 of the feed conduit housing is supplied with a partial pipe flange 66, the two partial flanges together forming a complete annular pipe flange. Because of the extremely high hydrostatic heads utilized in introducing feed slurry into feed conduit 18, a pressure seal between the hydrocyclone feed conduit housing and the feed conduit member 32, should preferably be provided to prevent leakage, for example, into the space between the casing and the various parts forming the chamber 12. Accordingly, the feed conduit member 32 in the drawings has been provided with an outwardly extending annular seal member 34 which rests against the face of the pipe flange formed by the partial pipe flanges 64 and 66 and preferably, in a cooperative cut-away portion in the respective faces of the partial flanges. Appropriately spaced bolt holes 69 are provided in the partial flanges for securing thereto by bolt and nut combinations the feed supply conduit.

The overflow discharge conduit member 54 may be flange 68 and nut and bolt combinations in conjunction with appropriately spaced bolt holes 69 disposed in said pipe flange.

To minimize vibration the vortex finder member 38 is provided with a stiffener 70 which is formed by a cylindrical core member 72 and annular flange member 74. To minimize longitudinal extrusion of the underflow nozzle section, an underflow nozzle stiffener 76 is shown which comprises a cylindrical core member 78 and an annular flange member 80.

In any application of the hydrocyclone constructed according to this invention it may be desirable to be able to regulate the rate of underflow discharge through orifice 22 during operation. When using an underflow nozzle section of a resilient material such as molded rubber, regulation can be obtained by means of a clamp ring 82 having tightening means 84. Said clamp ring is disposed on the outside of the underflow nozzle section but below the end of the cylindrical core member 78. By adjustment of the tightening means 84 the cross sectional area of the underflow discharge orifice 22 may be con stricted to what is desired for the expected operating condition and then enlarged or further constricted during operation as desired.

Under operative conditions, because of the large hydrostatic head of the contents in the chamber 12 and the large centrifugal forces developed therein, there is always the danger of leakage through the joints formed between the adjacent surfaces of the various sections of the cylinder, of the infeed section of the cylinder and the orifice plate, and of the end section of the cylinder and top of the apex valve. To prevent this leakage, the longitudinal dimensions of these various parts are preferably slightly oversize, and in addition, the adjacent surfaces may be interrupted by one or more V-shaped annular seal members 94 and annular cooperative grooves 92. When said parts are assembled, there is a longitudinal compression due to the slight oversize of the longitudinal dimensions, and this along with the V-shaped annular seal member and cooperative grooves, practically eleminates leakage at the joints.

The hydrocyclone is of the frusto-conical type. It is shown with the hollow cylinder infeed section 26 shaped internally as a cylinder and having maximum inside diameter D, and with the remaining sections of the cylinder having a gradually and continuously decreasing diameter from the maximum diameter D to the diameter of the underflow discharge outlet 22.

Because of the fantastically large centrifugal forces generally developed within the hydrocyclone and because of the fact that as the axis of revolution is approached the magnitude of centrifugal forces increases, materials discharged from the underflow orifice 22 in the frustoconical type hydrocyclone tend to form a conically shaped spray. Where it is desired to prevent spraying of the underflow discharge the underflow nozzle section may comprise an open-ended spray guard member 86 having an inside hollow space into which underflow discharge orifice 22 opens and which has a longitudinal axis of radial symmetry coinciding with the chamber 12 longitudinal axis 14. This space, it will be observed, has a radius larger than the radius of the orifice 22.

To insure establishing and maintaining proper alignment of the sections of the hollow cylinder 24, particularly in the frnsto-conical form of hydrocyclone, it may be desirable to provide, as shown, the surface of the intermediate section 28 adjacent the surface of the end section 30 with an annular instep 90 and to provide the adjacent surface of the end section with a cooperative, annular, stepped-up member 88. In the embodiment shown the diameter of the stepped-up member 88 is slightly larger at the base then at the top while the diameter of the annular instep 90 is similarly adapted to be larger at the lower end than that at the upper end. This further aids in establishing and maintaining alignment of the intermediate section 28 and end section 30.

For mounting the hydrocyclone there is provided on the embodiment shown in the drawings two mounting flange members 96 through which are disposed through the bolt holes 97 for attaching the hydrocyclone to girders or the like by means of bolt and nut combinations.

The hydrocyclone constructed according to the teachings of this invention not only represent a substantial saving in fabrication costs, replacement costs, operational and maintenance costs, as compared to the hydrocyclone structures in the prior art but also has the following listed structural and operational advantages:

(1) The splitting of the feed conduit housing, and the casing in a single plane makes possible a more rigid and heavier liner in the feed conduit and at the feed inlet as well as making possible the replacement of said liner;

(2) A safety factor is involved in the frusto-conical form of hydrocyclone in that the liner becomes progressively more thick in the direction of greater and greater wear;

(3) The underflow nozzle section, in the zone of greatest wear, is outside of the casing so that the casing is protected, and yet, the liner is thin enough so that it can be observed when, under operative conditions, the wear has reached the maximum;

(4) The unit is quickly dismantleable and dismountable for repair and/or alteration;

(5) The hydrocyclone can be easily and quickly converted into a larger or smaller hydrocyclone by the addition or subtraction of appropriate sections of the cylincler and the addition or substitution of housings of different sizes.

In describing the various elements of the hydrocyclone structure of this invention with reference to the upward and downward directions, it should be noted that the reference in such case is simply for the sake of convenience and is not a limitation on the described element, since, as noted previously, under operative conditions, the hydrocyclone can be operated in any position with equal efiiciency.

We claim:

1. A hydrocyclone comprising in combination a hollow body open at both ends, and composed of a sacrificial, wear resistant material, the inner surface of said body defining the major portion of a vortex space, the axis of radial symmetry of which coincides with the longitudinal axis of said body, said body being divided by planes normal to said axis of symmetry into removable sections with the section at the infeed end of the body containing tangential feed means integral therewith, and the section opposite the infeed and containing coaxial underflow discharge means; closure means composed of a sacrificial wear resistant material and disposed at the infeed end of said body, said closure means incorporating an overflow discharge means; an underflow nozzle section composed of a sacrificial, wear resistant material, with one end adjacent the body section containing the underflow discharge means, the hollow portion of said nozzle section comprising an extension of said vortex space; together with means composed of rigid, non-sacrificial material for fixedly retaining the assembly of wear resistant elements in pre-established, non-leaking relationship; said hydrocyclone being further characterized in that the sacrificial wear resistant material of which at least the overflow discharge means and the underflow nozzle are composed is a resilient material and in that stiffening means are provided in physically cooperative relationship with at least one of said resilient elements to minimize vibration thereof.

2. A hydrocyclone according to claim 1 wherein said stifiening means is disposed in physically cooperative relationship to said overflow discharge means.

3. A hydrocyclone according to claim 2 wherein said stiffening means comprises a generally cylindrical structure of rigid material embedded in said resilient material,

4. A hydrocyclone according to claim 1 wherein said stifiening means is disposed in physically cooperative relationship to said underflow nozzle.

5. A hydrocyclone according to claim 4 wherein the stiffening means comprises a generally cylindrical structure of rigid material embedded in said resilient material.

6. A hydrocyclone according to claim 1 wherein stiffening means are disposed in physically cooperative relationship with both said overflow discharge means and said underfiow nozzle.

7. A hydrocyclone according to claim 6 wherein said stiffening means comprises a generally cylindrical structure of rigid material embedded in said resilient material.

References Cited in the file of this patent UNITED STATES PATENTS Jones May 26, 1908 Fontein Feb. 9, 1954 FOREIGN PATENTS France Nov. 18, 1953

Images