AU781953B2 - Centrifuge with twin inlet - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT pplicant: WESTFALIA SEPARATOR FOOD TEC GMBH Invention Title: CENTRIFUGE WITH TWIN INLET The following statement is a full description of this invention, including the best method of performing it known to us: 2 CENTRIFUGE WITH TWIN INLET The invention relates to a centrifuge.

Centrifuges, in particular disk centrifuges, are known having the most varying constructions. When separating cold milk into cream and skimmed milk, the problem, that the cream cannot be discharged from the separator with a stripping disk due to processing reasons, arises. For this reason separators used for this purpose are generally provided with slide ring seals for the inlet and outlet.

By installing slide ring seals the inlet cross-sections (diameters) are greatly restricted, since the diameters of 15 the slide ring seals is limited due to their maximum S: circumferential and rubbing speeds.

However, to achieve great throughput capacities, the return S 2: pressure is to be accordingly increased, necessitating very high pressures by the pumps.

Accordingly, the object of the invention is to improve the generic centrifuge in such a manner that the pressures required for the cold milk separation can be reduced with e 25 the throughput remaining the same, or the throughput can be increased with the pressures remaining the same.

This objective is achieved by a disk centrifuge comprising: a centrifugal drum having at least one liquid discharge and having an intake device; the intake device having two separate intakes; each intake being concentric to an axis of rotation of the centrifugal drum; one of the intakes, a lower intake, leading from below through a hollow spindle into a common distributor in the centrifugal drum; the other intake, an upper intake, leading from H:\Luisa\Keep\Speci\50099-Ol.doc 19/04/05 3 above through an upper intake tube into the distributor; separate intake ducts being respectively connected to the two intakes in the distributor; and wherein the intake ducts lead into respectively separate ascending ducts in a plate stack in the centrifugal drum.

According to the invention, the inlet device has two separate inlets, which extend to the centrifugal drum concentrically with the axis of rotation of the centrifugal drum. The "double" inlet makes it feasible to halve the inlet pressure with the suppled quantity remaining the same in each inlet compared with only one inlet (irrespective whether it terminates at the top of the drum, or, as it is 15 known from the state-of-the-art, at the bottom) or correspondingly increase the throughput capacities with the oo ~pressure remaining.

Preferably at least one of the at least one liquid discharge is constructed without a separating disk.

Preferably intake pressure at the upper intake tube is o adjusted to be lower than discharge pressure at the at least one liquid discharge without a separating disk.

•Preferably a sliding ring seals off the upper intake tube from the at least one liquid discharge.

Preferably at least one of the at least one liquid discharge is constructed without a separating disk and a single joint sliding ring seal seals off the upper intake tube from the at least one liquid discharge without a separating disk.

By referring to the drawing an embodiment is described with reference to the accompanying drawings in which; Figure 1 shows a sectioned illustration of a disk centrifuge.

H:\Luis\Keep\Speci\50099-O1.doc 19/04/05 4 Figure 1 shows a disk centrifuge 2, that has a centrifuge drum 4, that has a tapered narrowing in the top region.

In the centre of the centrifuge drum 4 an inlet tube 6 is guided from above (concentrically with the axis of rotation), the tube terminating from above in the lower region of the centrifuge drum 4 in a distributor 8.

In the lower axial end region of the centrifuge drum 4 a hollow spindle 11 is formed, onto which the bottom part of the drum is placed and which has at least two bores 13 that terminate in the inlet channels 12, 14 in the distributor.

Thus, the centrifuge drum 4 has two separate inlets which together form the inlet device of the disk centrifuge 2.

o One inlet channel 12, communicates with the inlet 6 and the :o other channel 14 communicates with the hollow spindle. The 20 channels 12 and 14 terminate in separate riser channels 16, 18 in the disk packet 20 of the centrifuge drum 4.

For the discharge of two different fluid phases two fluid outlets 22, 24 are provided, one of which is provided with a 25 stripping disk 26 and the other has a stripping disk-free construction.

The disk centrifuge 2 operates as follows: The material to be centrifuged, in particular cold milk, is conveyed to the distributor 8 both through the top inlet tube 6 (arrow B) and the bottom hollow spindle 11 (arrow A), from the distributor the cold milk flows into the inlet channels 12, 14 separated from one another and from there into the riser channels 16, 18 in the disk packet 20 of the centrifuge drum 4.

H:\Luisa\Keep\Speci\50099-O1.doc 19/04/05 5 The skimmed milk is discharged through the fluid outlet 22 with the stripping disk 26, and the cream through the fluid outlet 24 without the stripping disk. A solids discharge 28 makes the removal of solid residues from the centrifuge drum 4 possible.

The sealing of the top inlet and of the top inlet tube 6 and the sealing of the stripping disk-free fluid outlet 24 is carried out by means of only one common slide ring seal This is feasible in particular because the inlet pressure P1 in the top inlet tube 6 is chosen to be smaller than the discharge pressure P2 in the stripping disk-free discharge, so that the load on the seal is unidirectional.

15 In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, ge the word "comprise", or variations such as "comprises" or "comprising", is used in an inclusive sense, i.e. to specify 20 the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

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Claims (4)

1. A disk centrifuge comprising: a centrifugal drum having at least one liquid discharge and having an intake device; the intake device having two separate intakes; each intake being concentric to an axis of rotation of the centrifugal drum; one of the intakes, a lower intake, leading from below through a hollow spindle into a common distributor in the centrifugal drum; the other intake, an upper intake, leading from 15 above through an upper intake tube into the distributor; separate intake ducts being respectively connected to the two intakes in the distributor; and wherein the intake ducts lead into respectively separate ascending ducts in a plate stack in the centrifugal drum.

2. The centrifuge according to claim 1, wherein at S* least one of the at least one liquid discharge is constructed without a separating disk.

3. The centrifuge according to claim 2, wherein intake pressure at the upper intake tube is adjusted to be lower than discharge pressure at the at least one liquid discharge without a separating disk.

4. The centrifuge according to claim 1, wherein a sliding ring seals off the upper intake tube from the at least one liquid discharge. H:\Luisa\Keep\Speci\50099-01.doc 19/04/05 7 The centrifuge according to claim 1, wherein at least one of the at least one liquid discharge is constructed without a separating disk and a single joint sliding ring seal seals off the upper intake tube from the at least one liquid discharge without a separating disk. Dated this 19th day of April 2005 WESTFALIA SEPARATOR AG By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia 4 94 C« f 9 C C* C* S 9 H:\Luisa\Keep\Speci\50099-01.doc 19/04/05