GB2185957A - Screw feeder - Google Patents

Abstract

A screw feeder for unloading bulked material from a ship's hold includes a screw 2, driven by motor 3 operating in an upright tube 1. The lower end of the screw projects below the lower end of the tube and a unit 5 rotates around the projecting end to urge material towards it. The unit contains blades 8 that are planar for most of their length but inclined in the sense that will, on rotation, urge material towards the projecting end. A second unit 15 surrounds the first; it rotates in the opposite sense but the blades 16 are so disposed to urge material towards the projecting end. The units are supported at 7 from the tube 1 by flanges which have ring gears driven to rotate the units by rotors 37 also located on the tube below an outlet 4 for the material to be unloaded. The lower ends of the units have bushes located upon a downward extension of the screw. <IMAGE>

Description

SPECIFICATION Improvements in or relating to screw feeders This invention relates to material feeding apparatus ofthe kind in which a tube houses a screw feederthat can be rotated about its axis. Such apparatus is useful in thetransfer of pulverulent or other bulked material from a ship's hold and an object ofthe invention is to facilitate the efficient use of the apparatus.

According to the present invention, there is provided material feeding apparatus comprising a tube and a feeder screw rotatable about its axis within the tube and that projects beyond the inlet end ofthe tube, and a unit comprising a plurality of bladesthat are spaced about, and extend generally lengthwise of, the projecting end of the screw, each blade being oblique, all in the same sense, to a diametrical plane ofthe unit and the unit being rotatable about the end of the screw in the direction such that, with the unit immersed in particulate material the material will tend to be moved by the blades towards the interior of the unit.

With such an arrangement, matter can be supplied with some uniformity to the whole length of the projecting end of the screw, and this will facilitate the efficient removal ofthe material at a consistent rate.

By way of example, a particular embodiment of the invention will now be described with reference to the accompanying somewhat schematic drawings in which Figure lisa side view of material feeding apparatus; and Figure2 is a partial cross-section taken on the line II - II of Figure 1.

The apparatus illustrated comprises a vertical tube 1 in which lies co-axially a feeder screw 2 constituted by a blade 2a winding spirally along a central stem 2b. The lower end of the feeder screw 2 projects some way belowthe lower end ofthetube 1 and the projecting part is provided with an additional screw blade 2aa so that the spacing between adjacent turns in the projecting portion is only halfthe spacing between adjacentturnswithin the tu be. A motor3 by which the feeder screw 2 can be driven in clockwise direction, seen from above, within the tube 1 is mounted on the upper end of the tube 1. Material raised by the feeder screw is discharged through the opening 4; devices by which the material can be conveyed from an opening such as 4 are well known in the art and none is illustrated here.

Concentric with, and embracing,the lower end of the tube 1 andthefeederscrew2 is a unit 5. The unit 5 comprises a sleeve 6, which depends from, and can be rotated in an anti-clockwise direction, seen from above,from a device7to be described morefully later.

The lower end of the sleeve 6 lies atthe lower end of the tube 1. Fixed to the sleeve 6 are five blades 8.

uniformly distributed around the sleeve 6. Each blade 8, for most of its length, is flat and planar. It is fixed along its inner edge to a generator of the sleeve 6 and is so inclined to a diametrical plane passing through the generatorthatwhen the unit rotates in an anti-clockwise direction, the outer edge ofthe blade leads the inner.

Whilst the blades 8 are planar for most oftheir length, the lower end of each is bent, at 8a, to bewelded at its end to a bush 9. The ends 8a are not only bent inwardly but slewed, all in the same sense, to provide in effect a screw of partofa turn; the slewing is apparent in Figure 2 from the way in which the end ofthe blade 8 joins the bush 9.

The lower end ofthe stem 2b is provided with a downward extension 10 that is received within the bush 9 so that the unit 5 and the screw 2 provide mutual supportfor each other at their "free" ends.

Concentric with, and embracing, the first unit is a second unit 15. This provides seven blades 16, uni formly spaced and generally similar to the blades 8.

Their inclination is opposite to that of the blades 8 in that the unit is arranged to rotate in a clockwise direction and outer edges of the blades, when the unit is rotating in that direction, lead the inner edges. The lower ends 1 6a of each of the blades 16 are bent and slewed as are the lower ends 8a ofthe blades 8; they are fixed to bush 18that also receives the lower end of the extension 10.

The units 5 and 15 are rotated from the device 7 mounted as a collar on, and around, the tube 1.The device 7 includes a casing provided by the horizontal plate 20, fastened around its inner periphery to a flange 21 projecting outwardly from the tube 1, and a skirt 22 depending from the outer periphery of the plate 20. Seals are provided between the fixed and the rotating parts, and between the rotating parts, of the device 7 to inhibit the entry into the device 7 of dust. Attwo diametrically opposite locations, there is mounted on the plate 20 a turning device, 23 and 24, by which a gearwheel, 25 and 26, below the plate 20 can be rotated. The turning devices 23 and 24 can be actuated by motors 37 mounted on the tube 1 just below the outlet 4.

Device 23 is effective for rotating the inner unit 5.

The upper end of the sleeve 6 is connected to an outwardly projecting flange 27 which carries at its outer edge a gear ring 28, teeth on the outer edge of which co-operate with teeth of the gearwheel 23 to turn the unit 5 in (seen from above) an anti-clockwise direction. A bearing for the ring 28 is provided by the ring 29 (fixed to the plate 20) and the interposed balls 30.

To rotate the outer unit 15, the device 24 is effective. The upper ends ofthe blades 16 are fixed to the ring 31 and can be rotated by engagement ofthe teeth on the inner edge ofthe gear ring 32, fixed to and extending upwardlyfrom the ring 31. A bearing for the gear ring 32 is provided by the ring 32 (fixed to the plate 20) and the interposed balls 34.

In operation of the apparatus described, the turning devices 23 and 24 are rotated simultaneously at the same speed with the result that the rings 28 and 32 and the units will rotate in opposite directions.

The directions of rotation are such that the blades that are rotated by the rings will tend to direct material in which they move towards the axis. The appar atusissetin motion above the bulk of material ion a ship's hold, for instance, that is to be moved. It is then lowered, the slewed lower ends of the blades 8 and 16 facilitating the movement of the apparatus into the material.The blades will urge the material towards the axis of the screw feederwhich in turn will raise the material up the tube to the opening through which it discharges for conveyance elsewhere The apparatus that has been described is especially useful when the material to be transferred is damp coal or other material that is heavy and not easily separated for it tends to gather, lift and impel the material whereas other commonly used appar atus tends to exert a squeezing effect during operations. It is envisaged, however, that where the mat erial to be transferred is light and dry, the apparatus described may be modified to include only one set of blades, and therefore only one unit, and that it may be possible to use blades that are not slewed and curved attheirlowerends.

CLAIMS 1. Material feeding apparatus comprising a tube and a feeder screw rotatable about its axis within the tube and that projects beyond the inlet wend ofthe tube,and a unit comprising a plurality of blades that are spaced about, and extend generally lengthwise of, the projecting end ofthe screw, each blade being oblique, all in the same sense, to a diametrical plane of the unitand the unit being rotatable about the end ofthe screw in the direction such that, with the unit immersed in particulate material, the material will tendto be moved bythe bladestowardstheinterior ofthe unit.

2. Material feeding apparatus as claimed in claim 1 in which the end portion of each blade most remote from the tube is curved towards the axis ofthe screw and slewed in such a way that the slewed portions have a boring effect as the blades are rotated in the sense specified in claim 1.

3. Material feeding apparatus as claimed in claim 2 in which the slewed portions of the blades all ter- minate in a bush in which is rotatably received the projecting end of the feeder screw.

4. Material feeding apparatus as claimed in any ofthe preceeding claims in which there is a second unit disposed around the first and that also satisifies the definition in any of claims 1 to 3 of the first unit.

5. Material feeding apparatus as claimed in claim 4 in which each of the blades of the second unit is inclined to its diametrical plane in the opposite sense to the inclination ofthe blades of the first unit and means are provided by which the units may be rotated simultaneously in opposite senses.

6. Material feeding apparatus as claimed in claim Sin which the tube is vertical, a casing mounted on, and encircling, the tube extends horizontally, the casing contains two rings concentric with each other and the tube, means is provided whereby the rings may be rotated in opposite senses, the first unit is connected concentrically to, and dependsfrom,the inner ring and the second unit is connected con centrically to, and depends, from the outer ring.

7. Material feeding apparatus as claimed in claim 6 in which the first unit comprises a sleeve encircling the tube, the sleeve is connected at its upper end to the inner ring and the blades depend downwardly from the sleeve.

8. Material feeding apparatus as claimed in claim 6 in which the blades of the second unit are each connected attheir upper ends to the outer ring.

9. Material feeding apparatus substantially as described with reference to, and as illustrated by the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. towards the axis of the screw feederwhich in turn will raise the material up the tube to the opening through which it discharges for conveyance elsewhere The apparatus that has been described is especially useful when the material to be transferred is damp coal or other material that is heavy and not easily separated for it tends to gather, lift and impel the material whereas other commonly used appar atus tends to exert a squeezing effect during operations.It is envisaged, however, that where the mat erial to be transferred is light and dry, the apparatus described may be modified to include only one set of blades, and therefore only one unit, and that it may be possible to use blades that are not slewed and curved attheirlowerends. CLAIMS

1. Material feeding apparatus comprising a tube and a feeder screw rotatable about its axis within the tube and that projects beyond the inlet wend ofthe tube,and a unit comprising a plurality of blades that are spaced about, and extend generally lengthwise of, the projecting end ofthe screw, each blade being oblique, all in the same sense, to a diametrical plane of the unitand the unit being rotatable about the end ofthe screw in the direction such that, with the unit immersed in particulate material, the material will tendto be moved bythe bladestowardstheinterior ofthe unit.

2. Material feeding apparatus as claimed in claim 1 in which the end portion of each blade most remote from the tube is curved towards the axis ofthe screw and slewed in such a way that the slewed portions have a boring effect as the blades are rotated in the sense specified in claim 1.

3. Material feeding apparatus as claimed in claim 2 in which the slewed portions of the blades all ter- minate in a bush in which is rotatably received the projecting end of the feeder screw.

4. Material feeding apparatus as claimed in any ofthe preceeding claims in which there is a second unit disposed around the first and that also satisifies the definition in any of claims 1 to 3 of the first unit.

5. Material feeding apparatus as claimed in claim 4 in which each of the blades of the second unit is inclined to its diametrical plane in the opposite sense to the inclination ofthe blades of the first unit and means are provided by which the units may be rotated simultaneously in opposite senses.

6. Material feeding apparatus as claimed in claim Sin which the tube is vertical, a casing mounted on, and encircling, the tube extends horizontally, the casing contains two rings concentric with each other and the tube, means is provided whereby the rings may be rotated in opposite senses, the first unit is connected concentrically to, and dependsfrom,the inner ring and the second unit is connected con centrically to, and depends, from the outer ring.

7. Material feeding apparatus as claimed in claim 6 in which the first unit comprises a sleeve encircling the tube, the sleeve is connected at its upper end to the inner ring and the blades depend downwardly from the sleeve.

8. Material feeding apparatus as claimed in claim 6 in which the blades of the second unit are each connected attheir upper ends to the outer ring.

9. Material feeding apparatus substantially as described with reference to, and as illustrated by the accompanying drawings.