GB2119671A

GB2119671A - Centrifugal screening drum

Info

Publication number: GB2119671A
Application number: GB08308206A
Authority: GB
Inventors: Rolf Butzler
Original assignee: Kloeckner Humboldt Deutz AG
Current assignee: Kloeckner Humboldt Deutz AG
Priority date: 1982-04-20
Filing date: 1983-03-24
Publication date: 1983-11-23
Also published as: ZA832781B; GB8308206D0; AU1295783A; DE3214404A1

Abstract

The reticulate drum 3 of a screening centrifuge is lined with wear-resistant sieve elements 1 which are secured to the drum via an intermediate layer 6 having apertures which are smaller than those of the drum and preferably coincident with those of the sieve elements. Layer 6 may be plastics or metal of perforate or mesh form, and elements 1 are metal or ceramic and may be glued to layer 6. The use of intermediate layer 6 reduces damage to elements 1 in use. <IMAGE>

Description

SPECIFICATION Wear resistant linings for a screening drum The invention is concerned with wear resistant linings for a screening drum, for example of a centrifuge, and with screening drums so lined.

Up to now, wear resistant linings in the form of sieve elements have been connected to the pierced screening drum of the centrifuge by glueing, soldering, welding, screwing or clamping.

It has been found in practice, however, that when the wear resistant sieve element, particularly if it is ceramic, is directly connected with the pierced screening drum, it cannot be avoided that in operation of the centrifuge individual webs of these sieve elements are sometimes broken. This is particularly true in the region of the relatively large fluid apertures in the wall of the screening drum. Replacement of the damaged or completely broken sieve elements is however extremely demanding in work, time and cost.

The object of the invention therefore lies in providing an arrangement by means of which the damage or breakage of the sieve elements is avoided or reduced, and the expenses of replacement.

Accordingly, the invention proposes a screening drum for a centrifuge having wear resistant sieve elements rigidly connected with the inner wall of the screening drum, wherein a thin intermediate layer, the apertures of which are smaller than those in the drum wall is arranged between the sieve elements and said wall.

Thus, the wear resistant sieve elements, particularly in the regions of the relatively large fluid openings in the screening drum cover, are provided with a fixed base or support, so that damage or breakage of the webs of the sieve elements is prevented. A further advantage of the intermediate layer consists in that even if the sieve elements are broken they are held in their original position and therefore do not need to be exchanged. Connection of the sieve elements with the thin intermediate layer and of the intermediate layer with the inner wall of the screening drum, can be effected in known manner by glueing, sawing, welding, screwing, etc.

In an advantageous development of the invention, the apertures in the intermediate layer are arranged to coincide with the apertures in the sieve elements. In this way, optimum backing or support of the sieve elements on the intermediate layer is achieved.

Further details, features and advantages of the invention will be obtained from the following explanation of an exemplary embodiment of the invention shown schematically in the drawings.

Fig. 1 shows a ceramic sieve element with an intermediate layer arranged between the screening drum inner wall and the sieve element, in perspective view; Fig. 2 shows a section on the line A-B in Figure 1.

Figures 1 and 2 show a sieve element 1, which is ceramic, which is matched in shape to the curvature in the direction of the arrow 2 of the screen 3. This ceramic sieve element 1 has several slit-iike apertures 4 through which the fluid coming from the solids can emerge. The slits 4, as can particularly by seen in Figure 2, widen in the outward direction, that is towards the wall of the drum 3, so that not only is the passage of the fluid made easier, but blockages of the slit-shaped sieve openings 4 are avoided. The screening drum 3 is internally completely clad with these ceramic sieve elements 1, both in the circumferential directions (arrow 2) and also in the axial direction (arrow 5).

The sieve elements 1 are rigidly connected with the inner wall of the screening drum using a thin intermediate layer 6, the apertures 7 of which are smaller than the apertures 8 of the wall of the drum. In the embodiment shown in Figures 1 and 2, the apertures 7 of the intermediate layer 6 are exactly the same size as, and arranged coincidental with, the slit-shaped outflow openings of the sieve elements 1. In this way, advantageously, each web 9 between the slits 4 is completely supported by the intermediate layer 6, so that breakage of the webs in particular in the region of the relatively large apertures 8 in the wall of the screening drum are reduced or prevented.The intermediate layer 6 is in this case advantageously provided on both sides with shoulders 10 running in the longitudinal direction of the screening drum, these shoulders entering corresponding recesses 11 on the faces of the ceramic sieve elements. In this way, advantageously, also in the circumferential direction of the drum, a smooth edge is achieved, with the ceramic sieve elements, laying closely adjacent one another. The intermediate layer 6 consists preferably of metal, so that it is very easy to connect it with the screening drum by welding, soldering, screwing or the like. The ceramic sieve elements 1, however, are best attached to the intermediate layer by glueing. In this way, on the one hand an optimal connection of the sieve elements with the intermediate layer 6, and on the other hand of the intermediate layer 6 with the screening drum 3, is achieved.

The arrangement for the rigid connection of highly wear resistant, in particular ceramic, sieve elements to the pierced screening drum of a centrifuge is not limited to the exemplary embodiment shown in the drawing. For example, the intermediate layer can advantageously consist of a pierced metal sheet, or a fine mesh netting. It is important in this case, however, that the apertures in the intermediate layer are smaller than the apertures of the drum wall. However, the intermediate layer 6 can, if required, be made of plastics material, rubber, or another material than metal. The highly wear resistant sieve elements can be made of sintered metal, or high-alloy steel, and have round, oval, or angular apertures.

1. A screening drum for a centrifuge having wear resistant sieve elements rigidly connected

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Wear resistant linings for a screening drum The invention is concerned with wear resistant linings for a screening drum, for example of a centrifuge, and with screening drums so lined. Up to now, wear resistant linings in the form of sieve elements have been connected to the pierced screening drum of the centrifuge by glueing, soldering, welding, screwing or clamping. It has been found in practice, however, that when the wear resistant sieve element, particularly if it is ceramic, is directly connected with the pierced screening drum, it cannot be avoided that in operation of the centrifuge individual webs of these sieve elements are sometimes broken. This is particularly true in the region of the relatively large fluid apertures in the wall of the screening drum. Replacement of the damaged or completely broken sieve elements is however extremely demanding in work, time and cost. The object of the invention therefore lies in providing an arrangement by means of which the damage or breakage of the sieve elements is avoided or reduced, and the expenses of replacement. Accordingly, the invention proposes a screening drum for a centrifuge having wear resistant sieve elements rigidly connected with the inner wall of the screening drum, wherein a thin intermediate layer, the apertures of which are smaller than those in the drum wall is arranged between the sieve elements and said wall. Thus, the wear resistant sieve elements, particularly in the regions of the relatively large fluid openings in the screening drum cover, are provided with a fixed base or support, so that damage or breakage of the webs of the sieve elements is prevented. A further advantage of the intermediate layer consists in that even if the sieve elements are broken they are held in their original position and therefore do not need to be exchanged. Connection of the sieve elements with the thin intermediate layer and of the intermediate layer with the inner wall of the screening drum, can be effected in known manner by glueing, sawing, welding, screwing, etc. In an advantageous development of the invention, the apertures in the intermediate layer are arranged to coincide with the apertures in the sieve elements. In this way, optimum backing or support of the sieve elements on the intermediate layer is achieved. Further details, features and advantages of the invention will be obtained from the following explanation of an exemplary embodiment of the invention shown schematically in the drawings. Fig. 1 shows a ceramic sieve element with an intermediate layer arranged between the screening drum inner wall and the sieve element, in perspective view; Fig. 2 shows a section on the line A-B in Figure 1. Figures 1 and 2 show a sieve element 1, which is ceramic, which is matched in shape to the curvature in the direction of the arrow 2 of the screen 3. This ceramic sieve element 1 has several slit-iike apertures 4 through which the fluid coming from the solids can emerge. The slits 4, as can particularly by seen in Figure 2, widen in the outward direction, that is towards the wall of the drum 3, so that not only is the passage of the fluid made easier, but blockages of the slit-shaped sieve openings 4 are avoided. The screening drum 3 is internally completely clad with these ceramic sieve elements 1, both in the circumferential directions (arrow 2) and also in the axial direction (arrow 5). The sieve elements 1 are rigidly connected with the inner wall of the screening drum using a thin intermediate layer 6, the apertures 7 of which are smaller than the apertures 8 of the wall of the drum. In the embodiment shown in Figures 1 and 2, the apertures 7 of the intermediate layer 6 are exactly the same size as, and arranged coincidental with, the slit-shaped outflow openings of the sieve elements 1. In this way, advantageously, each web 9 between the slits 4 is completely supported by the intermediate layer 6, so that breakage of the webs in particular in the region of the relatively large apertures 8 in the wall of the screening drum are reduced or prevented.The intermediate layer 6 is in this case advantageously provided on both sides with shoulders 10 running in the longitudinal direction of the screening drum, these shoulders entering corresponding recesses 11 on the faces of the ceramic sieve elements. In this way, advantageously, also in the circumferential direction of the drum, a smooth edge is achieved, with the ceramic sieve elements, laying closely adjacent one another. The intermediate layer 6 consists preferably of metal, so that it is very easy to connect it with the screening drum by welding, soldering, screwing or the like. The ceramic sieve elements 1, however, are best attached to the intermediate layer by glueing. In this way, on the one hand an optimal connection of the sieve elements with the intermediate layer 6, and on the other hand of the intermediate layer 6 with the screening drum 3, is achieved. The arrangement for the rigid connection of highly wear resistant, in particular ceramic, sieve elements to the pierced screening drum of a centrifuge is not limited to the exemplary embodiment shown in the drawing. For example, the intermediate layer can advantageously consist of a pierced metal sheet, or a fine mesh netting. It is important in this case, however, that the apertures in the intermediate layer are smaller than the apertures of the drum wall. However, the intermediate layer 6 can, if required, be made of plastics material, rubber, or another material than metal. The highly wear resistant sieve elements can be made of sintered metal, or high-alloy steel, and have round, oval, or angular apertures. CLAIMS

1. A screening drum for a centrifuge having wear resistant sieve elements rigidly connected with the inner wall of the screening drum, wherein a thin intermediate layer, the apertures of which are smaller than those in the drum wall is arranged between the sieve elements and said wall.

2. A drum according to claim 1, wherein the apertures of the intermediate layer coincide with the apertures of the sieve elements.

3. A drum according to claim 1 or claim 2, wherein the intermediate layer consists of an apertured layer or a fine mesh netting.

4. A drum according to claim 1, 2 or 3, wherein the intermediate layer consists of a plastics material.

5. A drum according to any preceding claim wherein the sieve elements are of ceramic material.

6. A screening drum for a centrifuge substantially as herein described in the accompanying drawing.