NZ214369A - Wool scouring apparatus with laminar plate settler - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £14369 214369 NEW ZEALAND PATENTS ACT, 1953 No.: 214,369 Date: 28 November 1985 COMPLETE SPECIFICATION "WOOL SCOURING APPARATUS" I/JKC HER MAJESTY THE QUEEN in Right of New Zealand, of Parliament Buildings, Wellington, New Zealand, ^ C hereby declare the invention for which -I / we-^pray that a patent may be granted to pie/w, and the method by which it is to be performed, to be particularly described in and by the following statement:- 4-.; 214369 This Invention relates to apparatus for the treatment of woolscour liquor within the woolscour industry, and in particular, but not solely, to apparatus for removing suspended solids and/or emulsified grease from the discharge liquor.

The preliminary processing of raw or slipe wool requires the wool to be scoured or washed with a cleansing liquor which is normally an aqueous soap or synthetic detergent solution. Grease, water soluble material and dirt are removed in the scouring process which typically consists of a train of 3 or 4 scouring bowls containing the cleansing liquor, followed by a maximum of two water rinsing bowls.

The effluent from scouring operations consists of a combination of grease, sulnt (the water soluble salts of the wool), dirt, vegetative matter, fine wool fibre and detergent. Untreated it is a highly polluting stream with biological oxygen demand (BOD5) values prior to dilution ranging from 15 to 60 kg/m^. It is desirable to reduce the volume of the liquor to be discharged and to lessen the suspended solids and grease content of this liquor.

Conventional wool scouring bowls typically consist of large tanks with sloping bottom sections. The wool is raked along a plate located in the top of the tank and is squeezed out through rollers before passing to the next bowl. The liquor is recirculated through the bowl via an adjacent sidebowl. A sidebowl is a bowl positioned alongside the main scour bowl enabling recirculation of the liquor through the main bowl. Modern bowls have hopper bottom sections for the discharge of sedimented solids. Grit and sand scoured from the wool settle readily to the bottoms of the bowls and are removed by time sequenced discharge through valves. However, the suspended solids concentration builds up during the operation of the scour system, due to an inability to sediment the fine particles. These particles are too small to be removed efficiently by a conventional settling tank. Improved scouring 214369 will result if the levels of suspended solids are minimised. This allows one both to reduce the required volumes of scour bowls and to increase the time intervals between dumps of liquor from the scour bowls, thereby reducing the overall rate of discharge of effluent 1iquor.

The scour operator will additionally be able to increase the specific throughput of wool per unit volume of scour liquor in the scour train, as improved scouring results due to the continuous removal of the suspended solids and other impurities, washed out of the wool, from the 1iquor.

It is therefore an object of the present invention to provide apparatus and/or a method to go some way toward achieving the abovementioned desiderata or at least to provide the public with a useful choice over the known art.

Accordingly the present invention may be said broadly to consist in a wool scouring apparatus including therein, in a portion of said apparatus through which wool scour liquor containing suspended solids is passed or in which wool scour liquor containing suspended solids is contained, a laminar plate settler and means associated with said settler for the removal of solids settled by said settler.

In one embodiment said settler is provided in a tank within a recycle loop in said apparatus.

In a second embodiment said settler is provided in the main scour bowl of said apparatus.

In a third embodiment said settler is provided in a sidebowl alongside the scour bowl of said apparatus.

In a fourth embodiment said settler is provided in a separate tank to treat the flocculated heavy solids discharged from each bowl.

Preferably in the second embodiment the scouring bowl is modified by sealing the wool-way plate from the bottom hopper section of the -4- 2143G9 main bowl thereby to reduce the bowl volume of an existing wool scouring apparatus.

Preferably there is provided a baffle positioned at the top section of said apparatus adjacent the collector of the settler.

Preferably said settler has a conically shaped bottom section and an outlet positioned at the centre of said section to aid the removal of the solids therefrom.

Preferably the plates of the settler are stacked in a cradle and are of an even length and width.

Preferably the plates of the settler are constructed from a galvanised and corrugated material.

Preferably said apparatus has a distributor pipe constructed of a single length of material of the desired shape (as herein described).

The invention may also be said broadly to consist in a wool scouring apparatus substantially as herein described with reference to the drawings accompanying the provisional specification.

In a further aspect the present invention may be said broadly to consist in a method of reducing the solids content of a woolscour liquor during a woolscouring process comprising passing a woolscour liquor with a high solids content through a laminar flow plate settler, which separates and partially removes both the solids fraction and the emulsified grease content therefrom.

Preferably said liquor is passed through said settler under pump suction conditions, with the settler uncovered or covered.

Alternatively said liquor is passed through said settler under pump pressure.

The invention consists in the foregoing and also envisages constructions of which the following gives examples.

The preferred form of the invention will now be described with reference to the drawings accompanying the provisional specification in 214369 which: Figure 1 is a schematic oblique pictorial view of a scour bowl and plate settler arrangement wherein the plate settler unit is installed in a recycle loop.

Figure 2 shows a perspective plan view of a laminar flow plate settler unit, schematically incorporated Into a recycle liquor treatment process.

Figures 3a-d show the desired shapes and profiles of the distributor and collector.

More specifically Figure 3a Is a vertical cross-sectional view of the distributor 32 In Figure 2.

Figure 3b is an oblique view of the distributor.

Figure 3c 1s a vertical cross-sectional view of the collector.

Figure 3d is an oblique view of the collector.

Figure 4 is a partially broken away oblique view showing the stack configuration in main elevation and the preferred shape of the plate settler unit.

A woolscouring process typically involves a train of three or four wash bowls followed by two rinse bowls. The wash liquor is fed typically from the last through to the first wash bowl, progressively increasing in solids, grease and other impurities content as it is fed from one bowl to the next. The wool is passed along the train countercurrently to the wash liquor. Most of the solids, dirt, grease and other impurities are removed from the wool in the first wash bowl.

Figure 1 shows squeeze roller 12 positioned above wool way plate 10. Underneath the roller and plate is the main scour bowl 17. A sidebowl 16 is shown positioned alongside main bowl 17. Separate to the bowls 16, 17, is plate settler tank 25.

Greasy wool is raked above a plate 10 located inside each scour bowl and squeezed out through squeeze roller 12 before passing (in the direction shown by arrow 11) to the next bowl. The liquor squeezed from the wool (indicated by arrow 14) and the makeup and flowback liquor (indicated by arrow 13) from the succeeding scour bowl (the total flow back is indicated by arrow 15) is normally recirculated via a recycle loop comprising sidebowl 16, pump 18 and heat exchanger 20. Heavy solids from the main bowl settle at the bottom and are discharged to a heavy solids tank via line 22.

In operation with the plate settler separate from the main and side bowls and the existing recycle loop, the scour liquor is removed from the conical bottom section 24 of the side bowl 16. The liquor is then fed into the plate settler tank 25. In the plate settler tank 25 part of the suspended solids are separated and the liquor is recycled into the main bowl 17 via pump 48. The separated suspended solids are collected from the conically shaped bottom section 36 of the plate settler tank 25 and discharged to the heavy solids tank through line 38.

Figure 2 shows a plan perspective/schematic view of the apparatus of one embodiment of the present invention with the plate settler run under pump suction conditions. The conical bottom section 24 of the sidebowl 16 is shown. Plate settler tank 25 is located downstream of sidebowl 16 with pump 48 located in turn further downstream.

The scour liquor flows through line 28 into distributor 32 of the p'late settler 25. Valves 33 and 51 are used for taking samples of the liquor before and after treatment.

Figure 3a shows a preferred profile of the distributor. The liquor flows through inlet holes 37 and out through the exit gap 41 between the bottom 43 and side 45 of the distributor, thereby achieving the desired distribution of the liquor along the length of the distributor.

Passage of the liquor through the free cross-sectional area of the 214369 plate stack 34 alters the turbulent flow condition of the scour liquor to a laminar flow condition. This enables the heavy solids to settle and grease droplets to rise to the surface.

The sludge stream is collected from the bottom 36 of the settler tank 25 and pumped from the settler through line 38 to the heavy solids tank. The recycle liquor reduced In solids is removed from the settler through collector 40.

Figures 3c and 3d show respectively the preferred profile and an oblique view of the collector 40. The liquor enters the collector 40 through the entry gap between weir 46 and edge 47 and exits through outlet pipes 42. The recycle scour liquor is then passed via line 50 through pump 48 before being fed Into main scour bowl 17. A baffle 44 Is placed across the top of the settler, in front of the collector 40, to reduce the top surface flow across the plates when the settler is run under pump suction conditions.

A preferred shape of the plate settler is shown in Figure 4. The plates 34 are of an even length and width and are stacked in a cradle held by brackets 53 and threaded rods 55. Spacers 57 assist in positioning plates 34 of the stack. The plates 34 are preferably constructed from galvanised material, are corrugated, hang in a vertical plane and lie equally spaced at all points from each other. The preferred material of construction of the plate settler tank and connections is stainless steel.

The bottom section 36 of the plate settler 25 is conical in shape and the solids outlet 52 is provided at its centre.

The form of the invention described incorporates the plate settler unit in a separate recycle loop wherein the plates are supported within a cradle and tank of the described shape. However, the plate stack can be located directly inside the main wash bowl or side bowl thereby reducing the required constructional space. 214369 Incorporation of a laminar flow plate settler of the above design into a commercial woolscouring train and In parallel with the first wash bowl enabled a 301 increase in suspended solids deposition from scour liquor when compared to a scour train without such a plate settler installed.

Claims (16)

WHAT WE CLAIM IS:

1. A wool scouring apparatus Including therein, in a portion of said apparatus through which wool scour liquor containing suspended solids is passed or in which wool scour liquor containing suspended solids is contained, a laminar plate settler and means associated with said settler for the removal of solids settled by said settler.

2. An apparatus as claimed in claim 1 wherein said settler is provided in a tank within a recycle loop in said apparatus.

3. An apparatus as claimed in claim 1 wherein said settler is provided in the main scour bowl of said apparatus.

4. An apparatus as claimed in claim 3 wherein said settler is provided in a sidebowl alongside the main scour bowl of said apparatus.

5. An apparatus as claimed in claim 1 wherein said settler is provided in a separate tank to treat the flocculated heavy solids discharged from each bowl.

6. An apparatus as claimed in claim 3 wherein said scouring bowl is modified by sealing a wool-way plate from the bottom hopper section of the main bowl thereby to reduce the bowl volume of an existing wool scouring apparatus.

7. An apparatus according to any one of the preceding claims including a baffle positioned at the top section thereof adjacent the settler.

8. An apparatus according to any one of the preceding claims wherein said settler has a conically shaped bottom section and an outlet positioned at the centre of said section to aid the removal of the solids therefrom.

SEP 1987' ^ ^ ^ appara*us accordin9 to any one of the preceding claims wherein the plates of said settler are stacked in a cradle and are of an even C E \ >1 length and width.

10. An apparatus according to any one of the preceding claims wherein the plates of said settler are constructed from a galvanised and 7 -10- 214369 corrugated material.

11. An apparatus as claimed 1n any one of the preceding claims including a distributor pipe constructed of a single length of material of the desired shape (as herein described).

12. A wool scouring apparatus substantially as herein described with reference to the drawings accompanying the provisional specification.

13. A method of reducing the solids content of a wool scour liquor during a woolscouring process comprising passing a woolscour liquor with a high solids content through a laminar flow plate settler, to thereby separate and partially remove both the solids fraction and the emulsified grease content therefrom.

14. A method according to claim 13 wherein said liquor is passed through said settler under pump suction conditions, with the settler uncovered or covered.

15. A method according to claim 13 wherein said liquor is passed through said settler under pump pressure.

16. A method of reducing the solids content of a wool scour liquor during a wool scouring process substantially as herein described with reference to the drawings accompanying the provisional specification. V'