AU635896B2 - An inlet launder for a clarifyer - Google Patents

Description

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AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Applicant(s): Contra-Shear Holdings Limited 31 Bancroft Crescent, Glendene, Auckland, NEW ZEALAND Address for Service is: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Complete Specification for the invention entitled: AN INTET LAUNDER FOR A CLARIFYER Our Ref 147980 POF Code: 9387/107876 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): 1 6006 2 This invention relates to an inlet launder for a liquid clarifyer. The inlet launder is particularly useful when used in a "cone tree" a clarifyer.

"Cone tree" clarifyers are well known in the art and are frequently used in applications where a liquid needs to be continuously clarified. An early example of such a clarifyer is described in U.S. patent 2314977. "Cone tree" clarifyers comprise a settling tank containing a plurality of "cone trees". Each "cone tree" consists of a large number of stacked cones, closely assembled one on top of the other on a central pipe. The central pipe serves as S' the support for the cones and as a means by which clarified o0 Soi fluid is discharged.

00 04 0o 0 o Murky or dirty liquid is input to the clarifyer and 9000*t sinks downwardly past the cones. The liquid then flows upwardly between adjacent cones, through ports in the central pipe, into the central pipe and out of the system.

While flowing up between a pair of cones, solid matter 0 carried by the liquid sediments on the surface of the lower o o* 0 0 cone and falls, under the action of gravity, down the 0 0 0 surface of the cone and to the bottom of the clarifyer.

Accumulated sludge is then removed from the clarifyer.

"Cone tree" clarifyers operate reasonably well as a rough and ready first stage in the purification of liquids.

However, turbulence within the clarifyer often results in solid particles remaining in suspension in the liquid and hence exiting from the clarifyer with the liquid. In all prior art known to the applicant, the liquid to clarified is input to the clarifyer in such a way that turbulence is 11~~1~ -3often generated, particularly adjacent the cones, and hence the efficiency of the clarifyer is reduced.

Accordingly, it is an object of the invention to provide an inlet launder for a clarifyer which reduces the turbulence of liquid input to a "cone tree".

This invention provides and inlet launder for a "cone tree" clarifyer, the inlet launder comprising: a substantially conical member for spreading liquid input on it adjacent its apex; and a first annular baffle extending upwardly from the conical member, the annular baffle and the conical member 0 being co-axial.

o Preferably, the inlet launder further comprises a 0O 0 0 second annular baffle which extends upwardly from the conical member and co-axially with the conical member. The .0 00 ona second baffle is positioned adjacent the peripheral edge of the conical member and the first baffle Is positioned between the apex of the conical member and the second 0 0 0 baffle.

A plurality of slots through the conical member may be defined adjacent the second baffle for fluid to flow from the launder. Downwardly extending flanges may be ooaI provided adjacent each slot. The flanges may extend co- 1axially about the axis of the conical member.

Preferably, the inlet launder is mounted on the central pipe of a "cone tree" with the axis of the conical member coterminus with the axis of the central pipe.

The invention also extends to a "cone tree" clarifyer containing the inlet launder.

Liquid is input to the inlet launder on the apex of -4 the conical member. Then, the liquid is spread generally evenly across the surface of the conical member and flows downwardly until the first baffle is reached. The liquid flows over this baffle and from th inlet launder. In this way, the liquid is fed to the "cone tree" evenly. This reduces turbulence about the "cone tree".

An embodiment of the invention is described, by way of example only, with reference to the drawings in which: figure 1 is a perspective view of a clarifyer; and figure 2 is a cross-sectional view of the inlet launder of the clarifyer.

e A "cone tree" clarifyer 1 is illustrated in figure 1.

The clarifyer 1 comprises a separation tank 2 which has Sfrustro-conical bin 3 at its lower end. The bin 3 terminates in a sludge outlet 4. The sludge outlet 4 conventionally is provided with a valve (not show-., and the clarifyer 1 is supported by legs 5. An inlet pipe 6 extends upwardly from the upper face of the clarifyer 1 as illustrated in figure 1. The separation tank 2 is circular in plan and the inlet pipe 6 is attached to the tank 2 at the axis of the tank 2.

An inlet launder 13 is positioned within the tank 2 beneath the inlet pipe 6. The inlet launder 13, which is best illustrated in figure 2, comprises a conical member 14 which is positioned beneath the inlet pipe 6; the apex 18 of the conical member 14 being cotenrminus with the axis of the inlet pipe 6. A first annular baffle 15 extends upwardly from the conical member 14 and is co-axial with the conical member 14. The first baffle 15 is positioned approximately midway between the apex 18 of the conical 5 member 14 and the lower edge 19 of the conical member 14.

A substantially horizontally portion 20 extends radially outwardly from the lower edge 19 of the conical member 14. A second annular baffle 16 is attached to the radially outer edge of the horizontal portion A plurality of slots 21 (figure 1) are provided in the horizontal portion 20 for flow of fluid from the inlet launder 13. A peripheral flange 17 extends downwardly from the lower edge 19 of the conical member 14 adjacent each slot 21. The second annular baffle 16 extends below the *0 lower edge 19 of the conical member 14 to the same depth as 0 *Gt the flange 17.

The inlet launder 13 is mounted on the central pipe 0 10 of a "cone tree" 22. The central pipe 10 extends along 0000 the axis of the separation tank 2 11nom the inlet launder 13 to a position approximately in alignment with the start of the bin 3. A liquid outlet pipe 7 is attached to the 0061 00 4 central pipe 10 at a position a little beneath the inlet 0 0 0| launder 13. The lower end of the central pipe 10 is "20 connected to a wash liquid line 8. A valve 9 is positioned in the wash liquid line 8.

00o00 The "cone tree" comprises plurality of stacked cones 23 extending about the central pipe 10 in a conventional manner. The cones 23 are stacked such that liquid may flow upwardly between each pair of stacked cones 23. A plurality of outlet slots 12 are provided in the central pipe 10 immediately above each stacked cone 23. In this way, liquid may flow upwardly between a pair of stacked cones 23 and out through an outlet slot 12.

The diameter of the circle upon which the slots 21

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6 lie is larger than the diameter of each cone 23. In this way, liquid leaving the inlet launder sinks past the cones 23 and not on to the first cone 23.

In use, dirty or murky liquid is input to the clarifyer 1 through the inlet pipe 6. This liquid strikes the conical member 14 adjacent its apex 18. This distributes the liquid substantially evenly across the surface of the conical member 14 as the liquid flows downwardly toward the first annular baffle 15. Once the liquid reaches the first annular baffle 15, it is forced to oo a flow upwardly over the baffle 15. The liquid flow path is illustrated in figure 2 by the arrow A. Causing the liquid 0o to flow over the first annular baffle 15 results in further even distribution of the liquid across the surface of the conical member 14. The liquid then flows down the conical surface 14 to the substantially horizontal portion 20 and through the slots 21. The second annular baffle 16 reinforces the even distribution of the liquid across the O0 as conical surface 14 by daming the liquid. The liquid then 12CY flows from the inlet launder 13 into the clarifyer 1 proper as illustrated by arrows B in figure 2.

01 4Once in the clarifyer i, liquid and solids sink under o 4 the action of gravity toward the bottom the clarifyer 1.

Because liquid is continuously flowing into the clarifyer 1, the samle quantity of liquid must continuously flow from the clarifyer i. Therefore, the liquid is forced to flow upwardly between the stacked cones 23, through the outlets slots 12 and into the central pipe 10. From the central pipe 10, the liquid flows upwardly and out through the liquid outlet 7. Whilst flowing between the stacked cones -7 23, solids which are still entrained in the liquid may sediment on the cones 23 and slide under the action of gravity downwardly from the cones 23. In this away, a large proportion of solids is removed from the liquid before it flows out of the liquid outlet 7. Sludge which collects in the bin 3 may be removed from the clarifyer 1 through the sludge outlet 4.

A rotatable plate or scrapper (not shown) may be provided in the central pipe 10 to clear away any blockages in the outlets slots 12. Also, wash liquid may be input Sthrough the inlet 8 to clean the central pipe 10 and the cones 23. Plainly, the outlet slots 12 may be sized as required.

It will appreciated that the inlet launder 13 supplies the liquid to the "cone tree" 22 in an evenly distributed manner. This results in a significant reduction in the turbulence of the liquid adjacent the 04 "cone tree" 22. It is also to be noted that the slots 21 are positioned from the axis of the conical member 14 a S210 distance a littler greater than the outer radius of the cones 23. In this way, the fluid is directed around each cone 23 and not onto it. Even distribution of the liquid 0 and direction of the liquid around the cones 23 results in a reduction in the turbulence of liquid flowing around the cones 23. This improvemes the efficiency of the clarifyer 1.

Plainly, it is not necessary that the inlet launder 13 be used in a clarifyer which contains only one "cone tree" 22; the inlet launder 13 is applicable to clarifyers which contain batteries of "cone trees". It would be 8 appreciated that for most efficient operation, each "cone tree" will have its own inlet launder.

The inlet launder may be constructed of any suitable material depending upon the application for which the clarifyer is intended. Plastics and metals would be most convenient.

It is to be understood that numerous modifications and variations may be made to the described embodiment without departing from the scope of the invention as set 10 out in the claims.

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Claims (4)

1. 2. An inlet launder according to claim 1 further 10o comprising a second annular baffle extending upwardly from oo 0 the conical member and coaxial with the conical member, the second baffle positioned adjacent the periphery of the conical member, the first annular baffle being positioned between the apex of the conical member and the second annular baffle. 0 3. An inlet launder according to claim 2 in which a 0 a 0 0 I plurality of slots are defined in the conical member adjacent the join between the second annular baffle and the 0 0 conical member; the slots being arranged a distance from 0 o,20 the axis from the conical member greater than the radius of the cones in the "cone tree".
2. 4. An inlet launder according to claim 3 in which flanges extend downwardly from the conical member adjacent each slot. An inlet launder according to any one of claims 1 to 4 and mounted on a central pipe of the "cone tree". i 10
3. 6. An inlet launder according to claim 1 and substantially as described in this specification with reference to the accompanying drawings.
4. 7. A conetree clarifyer including an inlet launder according to any one of claims 1 to 6. DATED: September 1989 PHILLIPS ORMONDE FITZPATRICK Attorneys for: CONTRA-SHEAR HOLDINGS LIMITED I0 I 4 1 L_