WO1994001220A1

WO1994001220A1 - Centrifugal filter device

Info

Publication number: WO1994001220A1
Application number: PCT/AU1993/000335
Authority: WO
Inventors: Rowland Alexander Errington
Original assignee: Trylock Pty Ltd
Current assignee: Trylock Pty Ltd
Priority date: 1992-07-08
Filing date: 1993-07-08
Publication date: 1994-01-20
Anticipated expiration: 1995-01-08

Abstract

A centrifugal filter device (1) for treatment of liquid-containing substance which comprises: a rotatable inner chamber (10) at least partially open in its upper region, as viewed in use; a fixed outer housing (2) surrounding the inner chamber; and means for delivery (14) of the liquid containing substance to a selected region of the inner chamber, wherein the rotatable inner chamber is adapted to collect concentrated waste material deposited from the liquid-containing substance, and which inner chamber is removable to empty the concentrated waste material for disposal, the waste material being concentrated in the lower region of the inner chamber upon rotation, and wherein the major portion of the liquid exits from the inner chamber out of its open top upon rotation, the inner chamber being provided with drainage means to remove remaining liquid from the concentrated material.

Description

TITLE: CENTRIFUGAL FILTER DEVICE

HELD OF THE INVENTION: This invention relates to a filter device and in particular a filter device useful for recovering purified liquid from sludges, emulsions etc.

BACKGROUND OF THE INVENTION: There is a need for a simple cheap device for recovering liquid from industrial sludges and emulsions etc., firstly, to enable reuse of liquid and, secondly, to reduce the need to dispose of large quantities of sludge or emulsion. Thus it is much more convenient to dispose of a small quantity of a relatively concentrated filtered material, for example, in a landfill.

Normal filtration is too slow and it is an object of the present invention to provide a simpler and more efficient filter.

U.S. Patent No. 1,479,456 Cleveland discloses on page 1 at line 17 to 37:

"One common method employed at the present time of de-watering activated sludge or similar material is to discharge the sludge into a rotatable drum, at a point near its bottom, which imparts rotation to the material and results in the cake or mass, contained in the sludge, being thrown and held into contact with the sides of the drum, while the liquid or effluent overflows and is carried off from the top of the drum. This method embodies many objectionable features, resulting in lower efficiency and consequently small capacity of the machine, due to the fact that sludge discharged at the bottom of the drum will not reach the maximum number of revolutions per minute until it has travelled the entire height of the drum, which results in a slow and inefficient separation of the cake or mass from the effluent, and requires subsequent re-handling of the effluent." The disadvantages mentioned by Cleveland have not been experienced with the device according to the present invention and the advantages of the present invention are discussed below.

Referring to the Cleveland patent specification mentioned above, the device according to the invention provides an inexpensive, generally small capacity machine but at the same time does not suffer from the inherent vibration and short bearing life problems mentioned by Cleveland at lines 43 to 49 of page 1:

"A further objection results from the fact that it is impossible to obtain an even flow of sludge, the same being fed by gravity, thereby resulting in vibration of the drum which is injurious to the same and causes great wear upon the supporting bearing."

The device according to the invention is intended to remove small quantities of solids from solutions such as cleaning solutions, for example, wherein 3 kilograms of sludge may be deposited in 1600 litres per day, such as in certain caustic solutions.

Furthermore, in the device according to the invention, contrary to the Cleveland's assertion, deposited material builds up less rapidly at the lower end of the rotating bowl without the need for his complex feed arrangement. In the device according to the invention, a high proportion, such as 25% by weight of material, is deposited at the lower level and this may be due to the region of delivery of the liquid- containing substance to be processed.

BRIEF SUMMARY OF THE INVENTION:

This invention, therefore, provides a centrifugal filter device for treatment of liquid-containing substances which comprises: • a rotatable inner chamber at least partially open in its upper region, as viewed in use; and

• a fixed outer housing surrounding the inner chamber; and

• means for delivery of the liquid-containing substance to a selected region of the inner chamber,

wherein the rotatable inner chamber is adapted to collect concentrated waste material deposited from the liquid-containing substance, and which inner chamber is removable to empty the concentrated waste material for disposal, the waste material being concentrated in the lower region of the inner chamber upon rotation, and wherein the major portion of the liquid exits from the inner chamber out of its open top upon rotation, the inner chamber being provided with drainage means to remove remaining liquid from the waste material,

BRIEF DESCRIPTION OF THE DRAWINGS:

Figure 1 is a side view partly in cross-section of one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION:

The rotatable inner chamber is conveniently centrally located with respect to the vertical axis, as viewed in use, of the outer housing. Preferably the inner chamber is generally cylindrical having a wall upon which the concentrated waste material collects. Furthermore the inner chamber is preferably supplied with a partial closure which limits upward flow, as viewed in use, of concentrated waste material.

The housing comprises an outer wall which preferably extends substantially to the top, as viewed in use, of the inner chamber. The housing comprises a circumferential trough around the inner chamber. Preferably a cap, comprising a removable lid, fits over the top of the housing. More preferably the cap is provided with a circumferential downwardly extending side wall and a circumferential inwardly extending bottom. In combination the side wall and bottom of the cap and the top of the cap, form a circumferential chamber for purified liquid. Preferably at least a portion of the internal surface of the cap slopes inwardly and downwardly towards the vertical axis of the housing. Sloping in this way reduces the tendency for "splashback" of purified liquid onto the inner chamber thus braking the inner chamber.

Thus raw liquid-containing substance is preferably fed through the top of the cap, as viewed in use, into the inner chamber and purified liquid is extracted from the circumferential chamber formed as described above. Preferably the inlet for the liquid-containing substance supplies the liquid-containing substance to a region near the bottom of the inner chamber, more preferably near its central axis.

The term "liquid-containing substance" is to be given a broad interpretation as including material comprising various quantities of a solid usually in the form of a sludge, the sludge material being from relatively dilute to relatively concentrated.

This invention has been found particularly useful in removing sludge fro alkaline baths and various cleaning solvents.

Turning to Figure 1, a centrifugal filter device comprises a fixed, outer centrifug housing 2 connected in use to a lower motor 3 by an extended circumferentia casing 4. Housing 2 is supplied with a cap 5, comprising a lid 5A from whic depends a circumferential side wall 6. Side wall 6 is provided with a bottom which defines an internal, circumferential catchment chamber 8. A first exit port leads from the bottom of circumferential chamber 8. A cylindrical inner chamber 10 is located inside housing 2 and is supplied with an upper, inwardly extending, partial circumferential closure 11 and bottom 12. An inlet 14 extends through an opening 15 defined by partial closure 11 and further extends towards a demountable hub means 16.

Inner chamber 10 is mounted on a generally circular plate means 17 which is in turn connected to a generally cylindrical shaft means 18. Shaft means 18 is connected to a spindle 19 leading from motor 3 and located centrally in an upper motor shroud means 20.

Returning to inner chamber 10, an internal drain 21 located in bottom 12 leads to a channel 22,which in turn leads to external drain 23. External drain 23 leads int circumferential trough 24 at the bottom of space 25 which is located betwee housing 2 and inner chamber 10. A second exit port 26 leads out of trough 24.

In use, raw liquid-containing substance is injected into spinning inner chamber 10 concentrated sludge gathering on its vertical cylindrical wall. By removal of lid 5 from cap 5, using screw means 27 and 28, inner chamber 10 may be removed fo cleaning out of concentrated sludge. Liquid is centrifuged out through opening 1 and into circumferential chamber 8 and drains through first exit port 9. In additio some liquid drains from the sludge through internal drain 21, channel 22 an external drain 23 into trough 24 and out through second exit port 26. The inwardl and downwardly sloping surface of the upper circumferential edge of cap 5 i indicated by numeral 29 and projects liquid downwardly into circumferentia chamber 8. The filter device described is of particular value for batch operation.

Claims

The claims defining the invention are as follows:

1. A centrifugal filter device for treatment of liquid-containing substance whic comprises:

• a rotatable inner chamber at least partially open in its uppe region, as viewed in use;

• a fixed outer housing surrounding the inner chamber; and

• means for delivery of the liquid-containing substance to selected region of the inner chamber,

wherein the rotatable inner chamber is adapted to collect concentrated wast material deposited from the liquid-containing substance, and which inner chamb is removable to empty the concentrated waste material for disposal, the was material being concentrated in the lower region of the inner chamber upo rotation, and wherein the major portion of the liquid exits from the inner chamb out of its open top upon rotation, the inner chamber being provided with draina means to remove remaining liquid from the concentrated material.

2. A filter device as claimed in claim 1 wherein the housing comprises circumferential trough around the inner chamber.

3. A filter device as claimed in claim 1 or 2 wherein the inner chamber generally cylindrical having an internal wall upon which the concentrat waste material collects.

4. A filter device as claimed in any one of claims 1 to 3 wherein the inner chamber is supplied with a partial closure which limits upward flow, as viewed in use, of concentrated waste material.

5. A filter device as claimed in any one of claims 1 to 4, wherein the inner chamber is centrally located with respect to the vertical axis, as viewed in use of the outer housing.

6. A filter device as claimed in any one of claims 1 to 5, wherein the housing comprises an outer wall which extends substantially to the top, as viewed in use, of the inner chamber.

7. A filter device as claimed in any one of claims 1 to 6, wherein a cap, comprising a removable lid fits over the top of the housing.

8. A filter device as claimed in claim 7, wherein the cap is provided with a circumferential bottom which, in combination with the outer wall, the lid and a side wall of the cap, forms a circumferential chamber for purified liquids.

9. A filter device as claimed in any one of claims 1 to 8, wherein the raw liquid- containing substance is fed through the top of the device, as viewed in use into the inner chamber and purified liquid is extracted from th circumferential chamber.

10. A filter device as claimed in any on of claims 1 to 9, wherein the inlet for th raw sludge material supplies the hquid-containing substance to a region nea the bottom of the inner chamber.

11. A filter device as claimed in claim 10, wherein the raw liquid-containing substance is supplied to a region near the central axis of the inner chamber.

12. A filter device as claimed in any one of claims 7 to 11, wherein at least a portion of the inner face of the side wall slopes inwardly towards the vertical axis of the housing.

13. A filter as claimed in claim 1, substantially as described with reference to the accompanying drawings.