NZ195591A - Dust retention device for container opening - Google Patents

Description

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P.O. Journal No: Patents Form No. 5 NEW ZEALAND PATENTS ACT 19 53 COMPLETE SPECIFICATION DUST RETENTION DEVICE WE, BARRETT BURSTON (AUSTRALIA) LIMITED, a Victorian Company of 461 Bourke Street, Melbourne, 3000, Victoria, Australia, do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement:- (followod by page I A.} - 1A - i 9559 This invention relates to a dust retention device.

The dust retention device of this invention has particular application to tracksinks, dumpsinks, hoppers, chutes and other things which are intended to convey, 5 receive or contain particulate materials.

The handling of particulate material often creates dust and this dust can be difficult to retain or collect. This problem of dust arising from handling of particulate material is particularly acute in the case of dumpsinks, 10 hoppers and chutes and particularly so in the case where there is a large open surface area as dust extraction is expensive as large volumes of dust laden gas must be handled. for a passage to a container for particulate material, the dust retention means comprising a plurality of openings, a restrictor for each such opening so mounted as to normally restrict the respective opening and characterized in that each restrictor is of inverted V-shape cross-section and 20 extends across the respective opening, each restrictor comprising a central axis about which it is pivotally mounted and a leaf being an arm of the V-shape extending to each side and downwardly and outwardly thereof: the arrangement being such that unequal loading of the leaves will cause each 25 restrictor to pivot about the-respective central axis when loaded by particulate material in excess of a predetermined amount independently of the other restrictors to open the respective opening and dump material thereon and thereafter return to restrict the respective opening while the other 30 restrictors not so loaded remain in restricting condition to restrict egress of dust through their respective said openings.

The present invention provides a dust retention device 19559i * Preferred aspects of the invention will now be discussed.

The number of such openings and such restrictors is not of itself critical but it is to be noted that if there was only one opening and restrictor then the device would be no more effective than a door or like structure which, when closed, would restrict escape of dust but which, when open, would not restrict escape of dust. Further, the present invention has most merit in a situation in which some of the restrictors are in the open position but some of the restrictors are in the restricting position in that the restrictors in the open position let particulate material pass but those in the restricting position are restricting the escape of dust. Thus it is the restri ctors in the res tri cting posi tion, rather than those in the open position, which are primarily providing advantages.

Accordingly, it will be realized that, as a generalization, the more of such openings and such restrictors the better; of course, economic and size considerations will place an upper limit to the number.

Preferably there are at least 6 such openings and restrictors although considerably more is preferred.

Still further, since it is the restrictors which are in the restricting position which are providing benefit it is to be appreciated that the present invention has particular application in the 1 955 9 3. case in which the cross-sectional area of said passage is large with respect to the amount of particulate material to be passed therethrough in any one operation as less of the restrictors will move to the open 5 position and more will remain in the restricting position. In the last respect, the area over which the particulate material is distributed over the device in any one operation will also have an effect. The concept of a large cross-sectional area of said passage 10 must be understood in the context of the particulate material in question. For instance, in dealing with certain powders, one square metre of cross-sectiona1 passage area may be considered large whereas when dealing with kilotonne quantities of grain bulk 15 storage anything less than 100 square metres of cross-sectional passage area is unlikely to be considered 1arge.

Preferably each such restrictor comprises a flap mounted to move between the restricted and open 20 position and bias means adapted to bias each flap towards the restricting position.

The bias means may be a spring or a counterweight.

However, the use of springs and counterweights 25 on flaps is not preferred and at the present time it is more preferred that each such restrictor comprises a shutter extending across the respective opening, each shutter comprising a central axis about which it is pivotally mounted and a leaf extending to each side 30 thereof, the arrangement being such that unequal loading of the leaves will cause each shutter to move and dump and thereafter return as aforesaid.

Preferably each leaf of each shutter extends outwardly and downwardly from the respective central axis.

Since it might be possible for particulate material to initially substantially evenly load one or 5 more of the shutters and/or that particulate material could bridge over a number of the shutters it is preferred that directing means is provided to direct falling particulate material to unequally load one leaf with respect to the other leaf of selected ones 10 of the shutters.

In one instance of this a plurality of such shutters are parallel one to the other and said directing means is provided to unequally load one leaf of from every shutter to each tenth shutter preferably from 15 each one to fifth shutter.

However, in a more preferred instance said directing means is provided by a plurality of baffles of inverted V-shape cross-section, wherein a plurality of such shutters are parallel, wherein each baffle is 20 located to restrict loading of adjacent leaves of adjacent shutters and wherein from zero to not more than nine preferably from zero to four, shutters not associated with such baffles are located in between sets of adjacent shutters associated with such baffles.

Preferably said adjacent shutters are so spaced that said adjacent leaves cannot touch when said adjacent shutters pivot.

The shutters need not be so close to one another that they seal and indeed this is not preferred 30 for a number of practical considerations including that of allowing individual particles to trickle through gaps between the shutters. 25H t 955 The device of the present invention lends itself to modular construction. For instance in one instance a module of the device comprises a frame, from two to ten inverted, V-shape cross-section, parallel shutters pivotally mounted at the apices and a selected number of such baffles. Such modules may be assembled side-by-side and/or end-to-end to make a device in accordance with this invention of the size requi red.

Specific constructions of devices in accordance with this invention will now be described with the aid of the accompanying drawings in which:- Fig. 1 is a perspective view of a module, Fig. 2 is a plan view of the module, Fig. 3 is a cross-section on lines 3-3 in Figs. 1 and 2, Fig. 4 is a cross-section on lines 4-4 in Figs. 1 and 2, Fig. 5 is a cross-section similar to Fig. 3 but of a different module, Fig. 6 is a top plan view of a grain hopper but with a grille removed, Fig. 7 is a cross-section through the grain hopper on line 7-7 in Fig. 6, and Fig. 8 is a cross-section through the grain hopper on line 8-8 in Fig. 6.

The module shown in Figs. 1 - 4, comprises an : outer casing 5 comprising walls 2 and which is open at its top 3 and bottom 4.

Within the casing 5 are three V-shaped shutters 6, 7 and 8. The shutters 6-8 are mounted with the V-shape inverted and are pivotally mounted by '■ 1C3 - 6 ^ < 6 . means of rods 9 which pass into the walls 2 of the casing 5. The shutters 6-8 are held to the rods 9 by plates 21 which are welded to the shutters. The rods 9 carry washers 22 and nuts 23.

The module of Figs. 1 - 4 further includes two baffles 24 and 25 of inverted V-shape but with one leg longer than the other. When two such modules are placed side-by-side with the shorter leg of one baffle of one overlapping the longer leg of one baffle 10 of the other a generally equal length legged baffle will result; this last is generally shown by a dotted line 25' in Fig. 3.

In use, a plurality of such modules will be placed side-by-side and end-to-end to make up a dust 15 retaining device.

One instance of the use of a plurality of such modules is the hopper or dumpsink shown in Figs. 6 to 8.

That hopper, 31, comprises sides 32, a 20 bottom 34 which may discharge to a silo, supports 36 for a removable grille floor 37 and for a railway track 38 and for a plurality of the modules of Figs. 1 - 4 which are indicated generally in Fig. 6 and individually in Fig. 7 by "X".

In one specific instance the hopper was 6 metres wide and 18 metres long.

In use, railway trucks are run onto the track 38 and the trucks are then tipped or opened to discharge material which falls through the grille 30 floor 37 onto the modules X. Those of the shutters 6-8 which are unevenly loaded with grain will pivot to dump material. Further, the baffles 24 and 25 25H fess 9 1 I *:/ w? * ■ 7. ensure that the shutters 6 and 8 are unevenly loaded. Thus, unevenly loaded shutters 6 and 8 will immediately or eventually dump the material on them. This will also cause intermediate evenly loaded shutters to become 5 unevenly loaded and to tip and discharge. Those shutters which have not been loaded will not move and dust escape past them will be limited.

If desired, dust extraction means 41 may be provided and need not be so large as if the modules X 10 were not used. In this last respect, allowing gaps at the ends of the shutters 6 - 8, at the ends of the legs of the shutters 6-8 and between the baffles 24 and 25 and shutters 6 and 8 should result in the plan area of the hopper being at least 90% closed when no 15 shutter 6 - 8 is pivoted and results in a smaller fan being needed. Further, since it is unlikely that more than 25% of the shutters 6-8 will be open at any one time this also reduces the need to have a large fan. In this last respect if dust extraction is required 20 the volume of gas handled by dust extraction means may be 15% of the recommended volume required without a device in accordance with this invention.

It is to be noted that the angles made with the vertical by the legs of the shutters 6-8 and by 25 the baffles 24 and 25 are preferably greater than the angle of repose of the material being handled.

The module shown in Fig. 5 is similar to that of Figs. 1 - 4 excepting that shutter 7 has been omitted and the size has been correspondingly altered. 30 The claims form part of the disclosure of thi s speci fi cati on.

Modifications and adaptations may be made 25H 1955 9 1 8. to the above described without departing from the spirit and scope of this invention which includes every novel feature and combination of features disclosed herein. m 25H 9

Claims (9)

WHAT WE CLAIM IS:

1. A dust retention device for a passage to a container for particulate material, the dust retention means comprising a plurality of openings, a restrictor for each such opening so mounted as to normally restrict the respective opening and characterized in that each restrictor is of inverted V-shape cross-section and extends across the respective opening, each restrictor comprising a central axis about which it is pivotally mounted and a leaf being an arm of the V-shape extending to each side and downwardly and outwardly thereof: the arrangement being such that unequal loading of the leaves will cause each restrictor to pivot about the respective central axis when loaded by particulate material in excess of a predetermined amount independently of the other restrictors to open the respective opening and dump material thereon and thereafter return to restrict the respective opening while the other restrictors not so loaded remain in restricting condition to restrict egress of dust through their respective said openings

2. A dust retention device as claimed in claim 1, wherein there are at least six suchopenings each with a respective such restrictor.

3. A dust retention device as claimed in claim 1, wherein each such restrictor includes bias means adapted to bias the respective restrictor towards the restricting position.

4. A dust retention device as claimed in claim 3, wherein the bias means is a spring or a counterweight. i 9559 10

5. A dust retention device as claimed in any of claims 1 to 4, wherein directing means is provided to direct falling particulate material to unequally load one leaf with respect to the other leaf of selected ones of the restrictors.

6. A dust retention device as claimed in claim 5, wherein a plurality of such restrictors are parallel one to the other and said directing means is provided to unequally load one leaf of from every restrictor to each tenth restrictor preferably from each one to fifth restrictor.

7. A dust retention device as claimed in claim 5, wherein said directing means is provided by a plurality of baffles of inverted V-shaped cross-section, wherein a plurality of such restrictors are parallel, wherein each baffle is located to restrict loading of adjacent leaves of adjacent restrictors and wherein zero to not more than nine, preferably from zero to four, restrictors not associated with such baffles are located in between sets of adjacent restrictors associated with such baffles.

8. A dust retention device as claimed in claims 5 to 7, wherein the directing means are baffles formed with an inverted V-shape cross-section having two downwardly and outwardly extending legs,one leg extending nearly adjacent a said restrictor and the other leg being substantially shorter than the one leg.

9. A dust retention device substantially as hereinbefore drawings. described with reJ