AU2004202533A1 - Material handling dust control apparatus - Google Patents

Description

Date: 6/11/2004 Time: 11:51:40 AM Page 2 of 19 1 Material handling dust control apparatus The present invention relates to a material handling passive dust control apparatus of the type utilised to control dust during transfer operations such as occur when bulk materials such as coal come off the end of one conveyor and drop onto another conveyor. In particular the present invention discloses within a dust containment enclosure the use of an intermediate chute for preventing the splaying out of the material and dust particularly in cases where the drop involved in the transfer operation is large or where the material being transported is fine, dry particulate material such as alumina or cement clinker that requires additional measures to reduce the propensity to generate dust.

The chute can also eliminate free fall of the material and where the head pulley is offset from the ideal intersection point of the receiving conveyor it allows the material to be channelled so that the material is placed onto the receiving conveyor at the optimum intersection point Passive dust control systems for materials handling are known and in particular US Patent 6135171 describes a state of-the-art system of this type. Said Patent discloses a system for controlling dust emissions generated during transfer operations for bulk material when material is being moved from a first location to a second location and wherein the first and second locations are spaced from each other by a drop. The COMS ID No: SBMI-00787573 Received by IP Australia: Time 11:58 Date"(Y-M-d) 2004-06-11 Date: 6/111/2004 Time: 11:51:40 AM Page 3 of 19 2 system disclosed involves an enclosure member fully enclosing the area between the first and locations with a deflector member adjacent the first location and a chute member therebeneath leading onto the second location also contained within the enclosure; the enclosure and positioning of the deflector and chute therein being such that dust emissions generated during the fall of bulk material through the enclosure from the first location to the second location pass through an enlarged stilling chamber area within the enclosure adjacent the second location causing dust to settle before the air which carried the dust executes a return path up through the enclosure from the second location back towards the first location.

Whilst systems such as above described have been found to work well with small drop heights between the first and second locations it has been observed that such systems do not work well with drop heights approaching or exceeding three metres or when very fine particulate material is involved as the air flow associated with bulk material dropping through the enclosure tends to splay out and interfere with the return air flow path of the non-dust laden air passing back through the enclosure towards the first location. This interference of opposing airflows causes non-laminar and turbulent flow within the enclosure with mixing of non-dust laden air and dust laden air thereby reducing the effectivness of the stilling zones within the enclosure and placing COMS ID No: SBMI-00787573 Received by IP Australia: Time 11:58 Date 2004-06-11 Date: &111F2004 Time: 11:*51:40 AM Pg o1 Page 4 of 19 3 excessive reliance upon the seals where the bulk material enters and exits the enclosure,.

It is accordingly an object of the present invention to ameliorate the above disadvantage with existing dust control systenm or at least to provide the market with an alternative.

According to the present invention there is disclosed apparatus for controlling dust generated during transfer operations for bulk material when material is being moved from a first location to a second location and wherein some of the material is fine in nature and the first and second locations are spaced from each other by a drop; the apparatus comprising an enclosure member fully enclosing the area between the first and second locations with a deflector member adjacent the first location and a lower chute member leading onto the second location both contained within the enclosure; the deflector serving to direct bulk material exiting from the first location down towards the lower chute and the lower chute member serving to introduce the bulk material at a minimal turbulence generating angle onto the second location; an enclosed intermediate chute having an inlet and an outlet and extending between the deflector and lower chute; a stilling chamber area incorporated within the enclosure adjacent and above the second location for the purpose of allowing dust to settle before the air which carried the dust executes a return path through the enclosure from the second COMS ID No: SBMI-00787573 Received by IP Australia: Timne (I-tm) 11:58 Date 2004-06-11 Date: 6/11/2004 Time: 11:51:40 AM Page 5 of 19 4 location back towards the first location; the shape of the enclosure being such that there is a return path for air outside the intermediate chute between the intermediate chute and the inside of the enclosure wall adjacent the intermediate chute.

A number of embodiments of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a schematic cut away side elevation of a system in accordance with the present invention; Figures la and Ib are a schematic cut away side elevations of systems in accordance with the present invention having differing conveyor head alignments to that depicted in Figure land hence different chutes; Figure 2 is a perspective view of an alternate system in accordance with the present invention; Figure 3 is a perspective view of yet a further embodiment of the present invention having a dual chute; Figure 4 is a perspective view of a chute in accordance with the present invention having discharge control plates and a diverter gate; COMS ID No: SBMI-00787573 Received by IP Australia: Time 11:58 Date 2004-06-11 Date: 6/1112004 lime: 11:51:40 AmPae at1 Page 6 of 19 Figure 5 is a perspective view of a chute in accordance with the present invention finted with anti flow back seals and; Figure 6 is a perspective view of the entrance to a dust control chamber in accordance with the present invention having a rubber curtain as a seal.

According to the embodiment of Figure 1 there is disclosed a dust control enclosure 1 having an inlet aperture 2 into which a first conveyor belt 3 feeds bulk material (not shown). Bulk material fed into enclosure 1 by first conveyor 3 follows the path labelled 4 and indicated in dotted configuration with the directional arrows. It will be appreciated that the bulk material after leaving the end of conveyor 3 first encounters deflector 5 which directs the material downwardly into intermediate chute 6 which controls the rate of descent of the bulk material through most of the drop over which the intermediate chute extends by forcing such material to adopt an shaped drop path. Intermediate chutes in accordance with the present invention need not necessarily involve nonlinear drop paths although in many instances where the drop path can be equivalent to several stories of a building such drop paths are desirable to slow the rate of decent and hence the rate at which the material hits the lower chute. It is additionally the case that multiple conveyors may feed into the same intermediate chute at different heights. Alter the bulk material exits the bottom 7 of intermediate chute 6 its direction of travel COMS ID No: SBMI-00787573 Received by IP Australia: Time 11:58 Date 2004-06-11 Date: 6/111/2004 Time: 11:51:40AM Page 7 of 19 6 is defined by lower chute 8 which leads smoothly on to the discharge location 9 atop second conveyor That part of dust enclosure 1 lying above second conveyor downstream of location 9 comprises an elongated stilling chamber 11.

Bulk material dropping through path 4 from the first conveyor discharge point adjacent the inlet aperture 2 of enclosure 1 to second conveyor carries with it a large volume of air (not shown) which in turn induces a similar large current of air travelling in the opposite direction up through enclosure 1 back towards inlet aperture 2. The upward travelling induced air current (not shown) is separated from the downward travelling air current by the walls of intermediate chute 6. The separation of these airflows is one of the principal purposes of intermediate chute 6 as the upward travelling air carries far less dust than the air travelling downwardly with the bulk material having regard to the fact that the upward travelling air has already passed through stilling chamber 11 which provides for settling of dust and other fine particulate matter (not shown) from the airflow. It will be appreciated that the separation of the two airflows reduces turbulence within the enclosure and facilitates the passage of relatively non dust laden air back towards inlet 2 thereby reducing reliance upon dust seals associated with inlet 2.

COMS ID No: SBMI-00787573 Received by IP Australia: Time 11:58 Date (Y-M-dJ 2004-06-11 Date: 6/112004 Time: 11:51:40AM Page 8 of 19 7 Preferably the cross sectional areas of the enclosed intermediate chute and the returned path for air outside the intermediate chute and within the enclosure are such that the velocity of air returning from the stilling zone adjacent the second location towards the first location is less than the velocity of material or dust laden air passing down the enclosed intermediate chute. The reduced velocity of the return air assists in precipitation of fine particulate matter.

Figure 1 shows the ideal location of the head pulley to the intersection point of the receiving conveyor below however, in a large number of cases, the head pulley of the delivery conveyor is either too far forward or too far back therefore requiring different shaped intermediate chutes to deliver the material to the correct place. Chutes designed to accommodate these variations are depicted in Figs IA The intermediate chute is an adaptable means of containing and controlling the material flow where the head pulley position of the delivery conveyor is not in alignment with the ideal intersection point of the centre of the receiving belt.

Figure 2 depicts a support structure 12 which may be contained within a dust enclosure 1 (not shown in full) as well as associated adjustment struts 13 which facilitate accurate placement, support, positioning and aiming of lower chute 8 and intermediate chute 6. These functions are additionally facilitated by a shims 14 resting on support structure 12.

COMS ID No: SBMI-00787573 Received by IP Australia: Time 11:58 Date 2004-06-11 Date: 6/1/2004 Time: 11:51:40AM Page 9 of 19 8 Figure 3 depicts a further embodiment of part of the system in accordance with the present invention having a split intermediate chute having two discharge outlets 16 and 17. In the drawing only discharge outlet 17 is shown as discharging into a lower chute 8 and a conveyor but chute 16 may similarly discharge on to a second lower chute (not shown) and another conveyor (not shown). The flow of bulk material down through intermediate chute 15 may be directed to either outlet 16 or outlet 17 by a flap valve (not shown) at position 18.

With reference now to Figure 4 a lower chute 19 is depicted containing a diversion gate 20 the purpose of which is to divert the bulk material towards one side or other of the conveyor (not shown) onto which it discharges. Such a diversion gate is often required when bulk material is presented to the lower chute at an angle other than vertical thereby causing the bulk material to flow to one side or other of the chute and hence discharge unevenly onto a conveyor With further reference to Figure 4 the chute is also depicted fitted with discharge control plates 26 which contain and direct the material exiting the chute in order to ensure correct loading onto the receiving belt (not shown). These control plates may be fixed or adjustable COMS ID No: SBMI-00787573 Received by IP Australia: Time 11:58 Date 2004-06-11 Date: 6/11112004 Time: 11:51:40 AM Page 10 of 19 9 With reference now to Figure 5 there is depicted a lower chute 8 having an anti flow back seal 25 designed to prevent material rolling underneath the bottom of lower chute during stopping and starting of the conveyor particularly in cases where the receiving conveyor is set at an incline as depicted in Figure 5. The seal is designed to fit snugly against the conveyor belt With reference now to Figure 6 there is depicted an inlet aperture 2 to dust enclosure 1 through which a laden conveyor belt 21 passes upon entry into the dust enclosure 1 and a second aperture 22 through which the same but empty conveyor belt 23 exits from the enclosure 1 after having discharged its load (not shown). In order that dust enclosure 1 prevent dust from exiting the enclosure both inlet aperture 2 and outlet aperture 22 are provided with rubber curtains 23 and 24 respectively. It will be appreciated that due to the loading of the belt entering aperture 2 curtain 23 is shaped differently to curtain 24.

It will be appreciated that alternate embodiments apart from those above described may be devised without departing from the scope and internment of the present invention.

COMS ID No: SBMI-00787573 Received by IP Australia: Time 11:58 Date'(Y-M-d) 2004-06-11