GB1601831A - Centrifuge apparatus - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO CENTRIFUGE APPARATUS (71) We, N. GREENING LIMITED, A British Company of Britannia Works, Bewsey Road, Warrington, Cheshire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to centrifuge apparatus such as is used for dewatering or separating particulate materials.

Such apparatus often comprises a cylindrical or conical drum having an apertures lining. Particulate material is fed into the drum from one end and the drum rotated.

The liquids or fine particles to be removed pass through the apertures and the residue is then removed via the end of the drum. In some cases the particulate material is fed into one end of the drum and the residue extracted via the other end.

A disadvantage of such centrifuge apparatus is that the lining is usually subject to differential wear, and it may be inconvenient and/or expensive to replace the entire lining when only a small part is worn.

An object of the present invention is to provide centrifuge apparatus in which the above disadvantage is mitigated or eliminated.

According to the present invention there is provided centrifuge apparatus comprising a drum including a support frame supporting a plurality of apertured elements disposed in one ore more bands around a circumference of the support frame, each element being attached to the support frame by engagement of a lug of the element with a lip formed by a recessed part of the frame. The support frame may, for example, be of circular, cylindrical, conical or polygpnal form.

Preferably the support frame and/or elements are composed at least partly of synthetic plastics material.

The plurality of elements may be disposed edge to edge around the drum interior, mutual support and/or location then being provided by a close fit of the complete band of elements with the support frame.

In preferred embodiments the support frame comprises a lattice and has several bands of elements disposed along its axis, each hole in the lattice conveniently being obscured by a single element. The elements may be preformed to conform to a curvature of the support frame or alternatively be so resilient as to so conform when all the elements have been inserted.

The support frame may be provided with attachment means whereby it can be secured to an existing support structure of a centrifuge machine for rotation therewith or, if of sufficient strength and rigidity, replace the usual cage-like support structure of the machine.

An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 is a sectional side view of a tapered centrifuge drum, Figure 2 is an end view of the drum, Figure 3 is a partial sectional view illustrating a preferred means of attaching individual elements to a support frame of the drum, Figure 4 is an underneath view of an individual element, and Figure 5 is a sectional partial view of an alternative means of attaching elements to the support frame of the drum and Figure 6 shows an element for attaching by the alternative means of Figure 5.

A centrifuge drum comprises a frustoconical steel cage formed by spaced hoops, 11, 12 and 13, and end flanges 14 and 15, joined together by bars 16 extending parallel to the drum axis. The drum cage is supported in known manner for rotation about its axis 10 by drive wheels 17 and 18 acting against the end flanges 14 and 15 respectively.

Attached to the interior of the cage by bolts 19 extending through the hoops is a polyurethane support frame 20 in the form of a lattice. A plurality of apertured, trapezoidal elements 21 are attached to the interior of the support frame, each in register with one of the holes of the lattice.

Each element 21 is of polyurethane and has a peripheral depending skirt 22 with an internal surface undercut to form a lug 23 whereby the element can be secured to the lattice support frame 20 by engagement with a lip 24 formed in one side of a groove 25 of inverted T-section in each cross-member of the lattice.

Referring now to Figures 5 and 6, which correspond to Figures 3 and 4, and illustrate an alternative embodiment of the invention the general form of the drum is again as shown in Figures 1 and 2 but the means of attaching the elements to the support frame has been modified. As shown in Figure 5, the support frame 30, again in the form of a lattice, is secured to the interior of the cage by bolts 19 moulded into the support frame and extending through the cage. Instead of the T-shaped groove 25, each cross-member of the lattice has a radially inwardly projecting flange 31 terminating in an enlarged beading portion or lip 32. The elements then have lugs 34 formed by undercuts or recesses 35 in the outer surface 36 of the peripheral skirt portion 37 of the element.The inner surface 38 of the skirt portion 37 are curved outwardly away from the screening surface so that when the elements are secured to the frame by lugs 34 engaging respective sides of the lip 32, the inner lower edge of the skirt aligns, approximately with the corresponding edge of the support frame cross-member.

This second embodiment allows narrower support-frame cross-members and element skirts to be used and so may provide for an increased open area for a particular size of centrifuge drum.

In the above described embodiments several circumfential bands of elements are arranged edge to edge along the length of the drum to provide a substantially uninterrupted surface and, since the diameter of each band is smaller the nearer it is to the apex of the drum, so the size of the elements is correspondingly smaller.

If desired or necessary the aperture size of different elements could be different according to the position of the element in the drum.

In operation particulate material is fed into the drum at the narrow end (A) and, as the drum rotates, fine particles and/or liquids pass through the apertures in the elements (B). The residue passes along the interior of the drum and emerges for collection at the wider end (C).

It will be appreciated that the above described embodiment could be modified in various ways as exemplified hereafter.

Where desired or preferred, rather than have different size elements for different bands, it would be possible to use standard size elements, at least for given drum tapers, and with special or cut infills for some bands, especially when edge interlocking is provided.

It is envisaged that a centrifuge drum might comprise a single band of identical elements, each extending from the top ring or one end flange to the bottom ring or other end flange. Different drum diameters and/or tapers might then be accommodated by using different numbers of such elements, with infills if required.

The shape of drum need not be conical but could be cylindrical or polygonal and in the latter case may be of truncated pyramidal section. Where the support frame is polygonal each element conveniently has a side of a length corresponding to a side of the polygon. Alternatively, a polygonal inner surface may be provided with a cylindrical or conical support frame, for example by disposing rigid flat elements chordally around the frame.

Instead of or in addition to being bolted, the support frame could be provided with ribs on its outer surface for engagement eith complementary slots in the support cage.

The provision of a support frame for securing to the cage is of advantage where it is required merely to convert an existing centrifuge for use with individually replaceable apertured elements, but if desired, it would be possible to make the support frame self-supporting perhaps provide it with hoops and end flanges, and dispense with the usual steel cage.

It will be appreciated that where the elements in each band are a close fit within the support frame they will be self-supporting, at least to some extent. To facilitate the process of lining the support frame with elements, it might be preferable to provide interlocking and/or bonding between adjacent elements or bands thereof, for example with axially adjacent bands of element located relative to each other by complementary formations e.g. stepped edges.

The elements may be entirely of synthetic plastics or of metal or a combination thereof, for example a die-cast metal body with a synthetic plastics mesh insert.

The elements may be preformed to a curved section corresponding to the interior of the support frame but resilient planar elements could be biassed to the required curvature on assembly and retained in the curved state by the circumferential forces when all the elements are in position.

Where it is not essential that the elements be curved in use rigid planar elements could be used to define a polygonal inner surface regardless of whether or not the support frame is polygonal. Conversely, resilient or curved elements could be used to provide a cylindrical surface within a polygonal support frame.

An advantage of embodiments of the invention is that they permit ready replacement of individual elements, although in some cases, say where elements interlock, it may be necessary or desirable to remove several other elements temporarily.

Although the specific embodiment is of a drum rotated about a horizontal axis the invention is readily applicable to drums rotatable about inclined or vertical axes and at high or low speeds.

WHAT WE CLAIM IS: 1. Centrifuge apparatus comprising a drum including a support frame supporting a plurality of apertured elements disposed in one or more bands around a circumference of the support frame, each element being attached to the support frame by engagement of a lug of the element with a lip formed by a recessed part of the frame.

2. Centrifuge apparatus as claimed in claim 1, wherein the elements in the or each band are arranged edge to edge around the drum interior.

3. Centrifuge apparatus as claimed in claim 2, wherein the elements depend for mutual support and/or location upon a close fit of the or each complete band of elements with the support frame.

4. Centifuge apparatus as claimed in claim 1, 2 or 3, wherein the support frame comprises a lattice and has several bands of elements disposed along its axis.

5. Centifuge apparatus as claimed in claim 4, wherein each element obscures a single hole of the lattice.

6. Centifuge apparatus as claimed in any preceding claim, wherein the lug is formed by an undercut or recessed outer peripheral surface of the element.

7. Centrifuge apparatus as claimed in claim 5 or 6 wherein the lip is carried by a flange extending radially inwardly of the support frame.

8. Centrifuge apparatus as claimed in any one of claims 1 to 5, wherein the lug is formed by an undercut or recessed inner surface of a peripheral skirt portion of the element.

9. Centrifuge apparatus as claimed in claim 8, wherein the lip is formed by one side of a groove of generally inverted T-section in a cross-member of the support frame.

10. Centrifuge apparatus as claimed in any preceding claim, wherein the elements are preformed to conform to a curvature of the support frame.

11. Centrifuge apparatus as claimed in any of claims 1 to 9, wherein the elements are so resilient as to conform to the support frame when fitted thereto.

12. Centrifuge apparatus as claimed in any preceding claim, wherein the drum tapers and at least some of the elements are trapezoidal.

13. Centrifuge apparatus as claimed in any preceding claim, wherein the support frame has means of attachment to a cage-like support structure of the drum.

14. Centrifuge apparatus as claimed in claim 13, wherein the attachment means comprises ribs for engagement with corresponding slots in the cage-like support structure.

15. Centrifuge apparatus as claimed in any preceding claim, wherein the support frame comprises a moulding of synthetic plastics material.

16. Centrifuge apparatus as claimed in any preceding claim wherein the elements comprise mouldings of synthetic plastics material.

17. Centifuge apparatus substantially as herein described with reference to, and as shown in, Figures 1, 2, 3 and 4 of the accompanying drawings.

18. Centrifuge apparatus substantially as herein described with reference to, and as shown in Figures 5 and 6 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (18)

**WARNING** start of CLMS field may overlap end of DESC **. be curved in use rigid planar elements could be used to define a polygonal inner surface regardless of whether or not the support frame is polygonal. Conversely, resilient or curved elements could be used to provide a cylindrical surface within a polygonal support frame. An advantage of embodiments of the invention is that they permit ready replacement of individual elements, although in some cases, say where elements interlock, it may be necessary or desirable to remove several other elements temporarily. Although the specific embodiment is of a drum rotated about a horizontal axis the invention is readily applicable to drums rotatable about inclined or vertical axes and at high or low speeds. WHAT WE CLAIM IS:

1. Centrifuge apparatus comprising a drum including a support frame supporting a plurality of apertured elements disposed in one or more bands around a circumference of the support frame, each element being attached to the support frame by engagement of a lug of the element with a lip formed by a recessed part of the frame.

2. Centrifuge apparatus as claimed in claim 1, wherein the elements in the or each band are arranged edge to edge around the drum interior.

3. Centrifuge apparatus as claimed in claim 2, wherein the elements depend for mutual support and/or location upon a close fit of the or each complete band of elements with the support frame.

4. Centifuge apparatus as claimed in claim 1, 2 or 3, wherein the support frame comprises a lattice and has several bands of elements disposed along its axis.

5. Centifuge apparatus as claimed in claim 4, wherein each element obscures a single hole of the lattice.

6. Centifuge apparatus as claimed in any preceding claim, wherein the lug is formed by an undercut or recessed outer peripheral surface of the element.

7. Centrifuge apparatus as claimed in claim 5 or 6 wherein the lip is carried by a flange extending radially inwardly of the support frame.

8. Centrifuge apparatus as claimed in any one of claims 1 to 5, wherein the lug is formed by an undercut or recessed inner surface of a peripheral skirt portion of the element.

9. Centrifuge apparatus as claimed in claim 8, wherein the lip is formed by one side of a groove of generally inverted T-section in a cross-member of the support frame.

10. Centrifuge apparatus as claimed in any preceding claim, wherein the elements are preformed to conform to a curvature of the support frame.

11. Centrifuge apparatus as claimed in any of claims 1 to 9, wherein the elements are so resilient as to conform to the support frame when fitted thereto.

12. Centrifuge apparatus as claimed in any preceding claim, wherein the drum tapers and at least some of the elements are trapezoidal.

13. Centrifuge apparatus as claimed in any preceding claim, wherein the support frame has means of attachment to a cage-like support structure of the drum.

14. Centrifuge apparatus as claimed in claim 13, wherein the attachment means comprises ribs for engagement with corresponding slots in the cage-like support structure.

15. Centrifuge apparatus as claimed in any preceding claim, wherein the support frame comprises a moulding of synthetic plastics material.

16. Centrifuge apparatus as claimed in any preceding claim wherein the elements comprise mouldings of synthetic plastics material.

17. Centifuge apparatus substantially as herein described with reference to, and as shown in, Figures 1, 2, 3 and 4 of the accompanying drawings.

18. Centrifuge apparatus substantially as herein described with reference to, and as shown in Figures 5 and 6 of the accompanying drawings.