CLASSIFIER CLEANING DEVICE

Abstract

A classifier cleaning and optimization device is provided. The device includes a chamber that is adapted to contain a fluidized bed, an array of two or more adjacently arranged inclined plates positioned above the fluidized bed wherein an inclined channel is formed between each pair of adjacent inclined plates, and a means for introducing a process liquid into the chamber between the fluidized bed and the array of inclined plates such that in use, the process fluid travels through at least one of the inclined channels. A method of cleaning the separation section of a classifier is also disclosed herein.

Claims

1. A classifier comprising: a chamber that is adapted to contain a fluidized bed; an array of two or more adjacently arranged inclined plates positioned above the fluidized bed wherein an inclined channel is formed between each pair of adjacent inclined plates; and a means for introducing a process liquid into the chamber below the array of inclined plates such that in use, the process liquid travels through at least one inclined channel.

2. The classifier of claim I wherein the introduction means comprises at least one fluid introduction tube extending to the chamber.

3. The classifier of claim 2 wherein the at least one fluid introduction tube is provided with a plurality of holes adaptable to pass the process liquid therethrough and into the chamber.

4. The classifier of claim 1 further comprising a distributor in fluid communication with the introduction means for alternatingly introducing the process liquid and a cleaning gas into the chamber such that in use, the process liquid and the cleaning gas alternatingly travel through the at least one inclined channel.

5. The classifier of claim 4 wherein the introduction means comprises a plurality of fluid introduction tubes that extend into the chamber, with each fluid introduction tube having a dedicated distributor with which it is in fluid communication.

6. The classifier of claim 5 wherein the cleaning gas is introduced alternatingly among each of the plurality of fluid introduction tubes according to a predetermined sequence.

7. The classifier of claim 6 wherein there is a plurality of arrays, with each array having a dedicated fluid introduction tube located directly beneath said each array.

8. The classifier of claim 7 wherein the fluid introduction tubes are provided with a plurality of holes positioned on an underside of each fluid introduction tube.

9. The classifier of claim 4 wherein the distributor is regulated by a controller.

10. The classifier of claim 4 wherein the process liquid is water and the cleaning gas is compressed air.

11. The classifier of claim 4 wherein the duration of the introduction of the cleaning gas is shorter than the duration of the introduction of the process liquid.

12. A method of cleaning inclined plates in a classifier comprising: forming a fluidized bed in a chamber; positioning an array of two or more adjacently arranged inclined plates above the fluidized bed wherein an inclined channel is formed between each pair of adjacent inclined plates; and introducing a process liquid into the chamber below the inclined plates such that in use, the process liquid travels through at least one inclined channel.

13. The method of claim 12 wherein the introduction step further comprises alternating the introduction of the process liquid and a cleaning gas into the chamber such that in use, the process liquid and cleaning gas alternatingly travel through the at least one inclined channel.

14. The method of claim 13 wherein the introduction step further comprises introducing the process liquid and the cleaning gas through a plurality of fluid introduction tubes.

15. The method of claim 14 wherein the introduction step further comprises alternating the introduction of the cleaning gas between each of the fluid introduction tubes according to a predetermined sequence.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Present preferred embodiments of classifiers are shown in the accompanying drawings.

[0037] FIG. 1 is a side view of a first present preferred embodiment of a classifier.

[0038] FIG. 2 is a top view of the first present preferred embodiment of a classifier.

[0039] FIG. 3 is a bottom view of the first present preferred embodiment of a classifier.

[0040] FIG. 4 is a close up view of the first present preferred embodiment of an introduction tube within a classifier.

[0041] FIG. 5 is a cross section view of the first present preferred embodiment of an introduction tube.

DETAILED DESCRIPTION OF PRESENT PREFERRED EMBODIMENTS

[0042] Referring to FIGS. 1-4, a classifier 1 is shown used to separate particles, which are located in a slurry, on the basis of both size and density. The classifier includes a chamber 2, a separation housing 104, an overflow outlet 3, a series of inclined plate arrays 101, a series of overflow launders 102, and a series of de-aeration chambers 201. The housing 104 is used to house the plate arrays 101, the launders 102, and the de-aeration chambers 201. The housing 104 is in fluid communication with the chamber 2. It should be appreciated that the housing 104 and the chamber 2 may be shaped and sized differently according to design requirement. It should also be appreciated that a top of the housing 104 is not shown in the FIGS in order to more clearly show the plate arrays 101 and launders 102.

[0043] In the depicted embodiment, there are eight sets of plate arrays 101. However, it should be appreciated that the number of plate arrays 101 may be varied depending on design criteria. Each plate array 101 is made up of spaced apart inclined plates 105 that preferably are substantially parallel. A series of inclined channels 107 are formed between each pair of inclined plates 105. A portion of the plate arrays 101 that is positioned in a portion of the housing 104A are arranged at an angle of inclination that is diametrically opposed to another portion of the plate arrays 101 that is positioned in another portion of the housing 104B. For clarity, only a minimal number of plates 105 are shown. It should appreciated that the number of plates 105, the size of the plates 105, the angle of inclination of the plates 105, the spacing of the plates 105, and the arrangement of the plate arrays 101 can be varied according to design criteria.

[0044] Three launders 102 located in each portion of the housing (104A, 104B) are used to catch the overflow material after it has passed through the plate arrays 101. The launders 102 are spaced between respective plate arrays 101. However, a person skilled in the art would appreciate number and type of launders 102 may be varied according to design criteria.

[0045] A collection channel 103 is formed at the end of the launders 102. The collection channel 103 is located between the housing portions (104A, 104B) to collect the overflow material once it has passed through the launders 103. The overflow outlet 3 is connected to the collection channel 103 to remove the overflow material from the housing to be transported for further processing.

[0046] In use, the feed slurry is passed through a central pipe 202 which divides into three de-aeration chambers 201 and then passes into the chamber 2. However, a person skilled in the art would appreciate the number and type of de-aeration chambers 201 may be varied according to design criteria. A plurality of fluidization nozzles 5 introduces fluidization fluid (not shown) into the chamber 2 creating a fluidized bed 6. A portion of the slurry and fluidization fluid then passes upwardly through the plate arrays 101 where particles located within the slurry are sorted according to a combination of size and density. The larger and denser particles pass into the bottom of the chamber where they are removed through the underflow outlet (not shown). The smaller and less dense particles are able to pass through the inclined channels 107 of the plate arrays 101 where they pass into launders 102, into the collector 103 and out of the overflow outlet 3.

[0047] The housing 104 is provided with a series of fluid introduction tubes 4 located below the plate arrays 101. A person skilled in the art would appreciate the type and number of introduction means may be varied according to design criteria, and that the fluid introduction tubes 4 can have differing cross-sectional configurations. Each fluid introduction tube 4 is provided with a series of holes 8 along the length of each fluid introduction tube 4. Each fluid introduction tube 4 is provided with a dedicated distributor 7. At any given time, the distributor may feed the process liquid 9, the cleaning gas 10, or a combination of both (9, 10) into the fluid introduction tube 4. It should be appreciated that the distributor 7 may accommodate more than two fluids according to design requirement. It should also be appreciated that the distributor 7 may not be required if only one fluid is to be introduced according to design requirement and that at times distributor 7 may not inject any fluid into the fluid introduction tube 4.

[0048] There are depicted four fluid introduction tubes 4 extending into each portion of the housing (104A, 104B). It should be appreciated that the number and position of the fluid introduction tubes 4 may be varied according to design requirement. In use, particles can buildup in the inclined channels 107. The process fluid 9 is fed through each of the distributors 7 where it passes into the respective fluid introduction tubes 4, through the respective holes 8, into the chamber 2, through the inclined channels 107 where it passes into launders 102, into the collector 103 and out of the overflow outlet 3. Alternatingly and for a set duration, the cleaning gas 10 is fed through one of the distributors 7 where it passes into the respective fluid introduction tube 4, through the respective holes 8, and into the chamber 2. The cleaning gas 10 creates bubbles (not shown) in the chamber 2 that travel through the inclined channels 107 of the plate arrays 101. The distributor may be regulated by a controller (not shown). It should be appreciated that introducing the cleaning gas 10 and/or the process liquid 9 into the classifier 1 can be accomplished according to a predetermined sequence or it can be done in accordance with operator or operational requirements. It should also be appreciated that the cleaning gas 10 could be constantly on.

[0049] The introduction of the process fluid 9 and the cleaning gas 10 into the chamber 2 between the plate arrays 101 and the fluidized bed 6 provides a number of benefits including removing built up material from the inclined channels 107 resulting in less maintenance downtime for the classifier 1 and optimization the flow through the inclined channels 107.

[0050] Referring to FIG. 5, there is shown a preferred embodiment of a fluid introduction tube 4 having a first row of holes 8A and a second row of holes 8B. The first row of holes 8A is located at substantially 135° (moving clockwise in FIG. 5) from a top 401 of the introduction tube 4 and the second row of holes 8B is located substantially 225° from the top 401 of the introduction tube 4. A person skilled in the art would appreciate the type, position, and number of holes 8 located in the introduction tubes 4 may be varied according to design criteria.

[0051] While certain present preferred embodiments of the classifier and method of using the same have been shown and described above, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.