GB2069375A

GB2069375A - Solid-sleeve screw centrifuge

Info

Publication number: GB2069375A
Application number: GB8039637A
Authority: GB
Original assignee: Kloeckner Humboldt Deutz AG
Current assignee: Kloeckner Humboldt Deutz AG
Priority date: 1980-02-16
Filing date: 1980-12-10
Publication date: 1981-08-26
Also published as: JPS56118757A; FR2475936A1; DE3005885A1; DK523280A; DD155299A5

Abstract

A solid-sleeve screw centrifuge comprises a cylindrical drum sleeve (1) and a screw conveyor (3), the drum sleeve being provided with openings (3) in the region at which the solid or heavier phase is extracted. <IMAGE>

Description

SPECIFICATION A solid-sleeve screw centrifuge The invention relates to a solid-sleeve screw centrifuge for continuously separating mixture of solids and liquids and mixtures of liquids of different density or phases of different weight.

The solid-sleeve screw centrifuges known up to now comprise a cylindrical drum sleeve and a conical sleeve as well as a screw conveyor arranged therein and shaped to be appropriately cylindrical and conical. In these known solidsleeve screw centrifuges, the solids or heavier phases are moved out of the liquid in the conical drum sleeve region with the aid of the screw conveyor in an upward direction and are extracted outwardly. Therefore, it is not possible to prevent the liquid which has been separated already from the solids or from the heavier phase from being mixed once again in this region with the solids or with the heavier phase. This can, in many cases be disadvantageous to the efficiency of separation.

Moreover, the arrangement of wear plates on the conical spirals of the screw conveyor is not only difficult to achieve but also involves higher financial and material costs.

The invention seeks to improve a solid-sleeve screw centrifuge in its construction by avoiding the disadvantages mentioned above and also to improve such a centrifuge in terms of its separating efficiency.

According to the invention there is provided a solid-sleeve screw centrifuge for continuously separating solids/liquids mixtures and mixtures of liquids of different density or phases of different weight, wherein the drum sleeve and the screw conveyor are cylindrical; and the drum sleeve is provided with openings in the area where the solid or heavier phase is extracted.

The openings may comprise nozzles.

Due to the fact that the drum sleeve and the screw conveyor are only cylindrical and no longer exhibit any conical elements, not only is there a considerable simplification of the construction of the centrifuge in comparison to known solidsleeve centrifuges, but also materials and costs can be cut down in a very advantageous manner.

Furthermore, due to the fact that the drum sleeve is provided with openings, more particularly nozzles, in the region where the solid or the heavier phase is extracted, the phases which have already been separated are safely prevented from mixing again and thus the separating efficiency is improved substantially.

The openings, more particularly nozzles, have different diameters. Therefore, the desired quantity of solids or heavier phases extracted can be influenced in a very advantageous manner.

The openings, more particularly nozzles, may be in active connection with a mechanically operated control device such that the openings in the drum sleeve or those of the nozzles are alternately covered or uncovered during movement of the screw conveyor relative to the drum sleeve. The extraction of solids or heavier phases can be varied automatically and optimized in terms of quantity by these measures in an advantageous manner by varying the relative speeds between the screw conveyor and the drum sleeve.

The invention will now be described in greater detail by way of example, with reference to the drawings, the single figure of which shows a solidsleeve screw centrifuge in accordance with the invention, schematically and in longitudinal section.

As the drawing shows the drum sleeve 1 and the screw conveyor 2 are cylindrical in the solidsleeve screw centrifuge. The drum sleeve 1 is provided with openings 3 in the area where the solid or the heavier phase is extracted, these openings 3 being distributed uniformly over the periphery of the drum sleeve. The screw conveyor 2 is arranged on a hollow shaft 4 which constitutes the screw body and which introduces the mixture of solids and liquids or the mixture of liquids of different density which are to be separated into the centrifuge drum in the direction of arrow 5.

During operation of this solid-sleeve screw centrifuge, the centrifuge drum 1 and the screw conveyor 2 are driven at different speeds, namely such that the screw conveyor 2 rotates at a slightly higher or slightly lower speed than the centrifuge drum 1.

Owing to the action of centrifugal force, the solids are separated from the liquid or the heavier phase is separated from the lighter phase, while the solids or the heavier phase is deposited in the base region of the drum sleeve and the liquid or lighter phase forms a layer thereabove. The solid or heavier phase is then taken by the screw conveyor 2 and transported to the opening 3 arranged in the extraction area of the drum sleeve and is extracted thereby in the direction of arrow 6. The liquid or lighter phase is removed outwardly through an opening, not shown in detail in the drawings, in the end walls of the drum sleeve 1 on the right-hand side of the solid-sleeve screw centrifuge as seen in the drawings in the direction of an arrow 7.

Because the drum sleeve 1 and the screw conveyor 2 are cylindrical and because the solid or heavier phase is extracted through the openings arranged in the drum sleeve 1, as compared to known solid-sleeve screw centrifuges there is no mixing of the phase in the extraction area which have already been separated so that the separating efficiency is considerably improved.

The solid sleeve screw centrifuge is also characterized by its very simple and economical construction. Instead of the openings 3 or in addition to the openings 3, nozzles 8 may also be arranged very advantageously on the drum sleeve, as shown in broken lines in the drawing. The drum sleeve is in active connection with a control device which is fixed to the holiow shaft 4 of the screw and is formed as ring 9 and is also shown in broken lines in the drawing, such that the openings 3 and/or the nozzles 8 are alternately covered or exposed during movement of the screw conveyor 2 relative to the drum sleeve 1. In order to achieve this, the annular disc 9 is preferably provided with apertures.

Due to this mechanically operated control device which is in active connection with the openings 3 and/or the nozzles 8, the quantity of the solids or heavier phase which is extracted may be varied very advantageously and the separating efficiency can therefore be improved. Moreover, the quantitative yield of solids or heavier phases from the centrifuge drum may be varied or altered very advantageously while the openings 3, more particularly the openings of the nozzles 8, have variable diameters. Simple and relatively resilient inserts only are required, the opening diameters of which can be varied within relatively broad limits by screwing them to a greater or lesser depth into the openings 3 or nozzles 8.

Claims

1. A solid-sleeve screw centrifuge for continuously separating solids/liquids mixtures and mixtures of liquids of different density or phases of different weight, wherein the drum sleeve and the screw conveyor are cylindrical; and the drum sleeve is provided with openings in the area where the solid or heavier phase is extracted.

2. A solid sleeve screw centrifuge according to claim 1, wherein the openings in the drum sleeve comprise nozzles.

3. A solid-sleeve screw centrifuge according to claim 1 or 2, wherein the openings have different diameters.

4. A solid-sleeve screw centrifuge according to claim 1, 2, or 3, wherein the openings are in operative connection with a mechanically operated control device for covering or uncovering the openings in the drum sleeve alternately during movement of the screw conveyor relative to the drum sleeve.

5. A solid-sleeve screw centrifuge according to any one of the preceding claims, wherein the control device comprises a ring arranged on the screw shaft.

6. A solid-sleeve screw centrifuge substantially as described herein with reference to the drawings.