GB2265922A

GB2265922A - Cleaning augers and screw-conveyors

Info

Publication number: GB2265922A
Application number: GB9207188A
Authority: GB
Inventors: Mak Wai Kei
Original assignee: STARLITE INVESTMENT Ltd
Current assignee: STARLITE INVESTMENT Ltd
Priority date: 1992-04-01
Filing date: 1992-04-01
Publication date: 1993-10-13
Also published as: GB9207188D0

Abstract

A device for removing adherent material from a helical flight (12) of an earth-boring auger or other screw-conveyor comprising scraping means (26a-f) adapted to scrape material from within the flight, and means (28) movably mounting the scraping means so that it is adapted to project into the flight and effect said scraping during rotation of the flight. <IMAGE>

Description

A DEVICE FOR REMOVING ADHERENT MATERIAL FROM AN EARTH BORING AUGER OR A SCREW CONVEYOR This invention relates to a device for removing adherent material from the helical flight of an auger or other form of screw conveyor.

During use of an earth-boring auger, it is quite common for the helical blade or flight to become clogged up with excavated soil and other debris.

Traditionally augers are cleaned manually with a pick, with a water jet or a combination of the two. This has the disadvantage that the scraping exercise is time consuming and labour intensive. In addition if a water jet is used the removed soil will be mixed with water and the waterlogged soil will make the site muddy which reduces productivity and may be dangerous. Also the waterlogged soil cannot be disposed of readily as most dumps permit only environmentally-stable waste.

One object of the present invention is to provide a device for removing adherent material from an earth-boring auger which overcomes at least some of the disadvantages of present methods. The invention also finds application to other screw conveyors for adherent material which may become similarly clogged.

According to one aspect of the present invention there is provided a device for removing adherent material from a helical flight of an earth-boring auger or other screw-conveyor comprising scraping means adapted to scrape material from within the flight, and means movably mounting the scraping means so that it is adapted to project into the flight and effect said scraping during rotation thereof.

This device has the advantage that the flight is efficiently and safely cleaned during use without the need for a time consuming separate exercise.

Preferably the scraping means comprises a plurality of scrapers adapted successively to enter and leave the flight during rotation thereof.

Advantageously the scraping means is in the form of a rotatably mounted wheel having a plurality of said scrapers thereon, or the scraping means is in the form of an endless chain, the scrapers being mounted on the links thereof.

Also advantageously the scraping means is movably mounted so as to accommodate longitudinal movement of the flight.

Preferably the wheel is mounted for free rotation or the chain is disposed around freely rotatable idler wheels.

The scraping means may include a brush adapted to clean a surface of the flight.

According to a second aspect of the invention there is provided an earth-boring equipment comprising an auger having a helical flight, or screw-conveyor equipment having a helical flight for conveying adherent material, said equipment having a device as set forth above.

Preferably the scrapers are spaced relatively to each other at a pitch such that they mesh with the flight.

This has the advantage that the flight and the scraping means mesh in a worm and gear like arrangement, the scraping means thereby accomodating the rotation of the flight.

Preferably said scraper is shaped to occupy substantially all of the space between successive pitches of the flight in the plane of the scraper, except for clearances necessary for rotation of the flight and for engagement and disengagement of the scraper with the flight during meshing thereof.

This feature has the advantage that the gear-like enagagement of the flight and the scraping means ensures that the majority of the area of the flight can be acted on by the scraping means.

Reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a schematic drawing of earth-boring equipment incorporating one embodiment of the present invention; Figure 2 is a cross-sectional diagram showing in more detail the scraping device included in Figure 1; and Figure 3 is a cross-sectional diagram of a second embodiment of the scraping device.

Referring to the illustrations an auger is shown generally at 10.

The auger has substantially a helical flight or blade 12 of constant pitch supported on a central shaft 14. Referring to Figure 1 in particular, the auger is shown drilling a pile shaft or other bore 16 in the ground. The auger is supported on a rig 18, 18a by a cable 19 and is hydraulically driven from a conventional power pack 20, via controller 20a, hydraulic pressure and return lines 20b, 20c (shown diagrammatically) and hydraulic motor 20d.

In addition the auger is also provided with a scraping wheel 22, and a chute 24 which catches adherent debris scraped off the flight by the scraping wheel as described hereafter.

The scraping wheel 22 is detachably mounted on brackets 23 (only one shown) to the rig 18 for rotation about a fixed horizontal axis.

Referring particularly to Figure 2, the scraping wheel 22 includes seven projecting scrapers 26a-26g disposed at the same circular pitch as the helical pitch of the flight. The scrapers successively enter the flight between the pitches thereof, and each is shaped so as to occupy substantially all of the space between adjacent pitches of the flight in the plane of the scraper, subject only to the clearances necessary for rotation of the auger and meshing of the scrapers therewith.

The scraping wheel is mounted on bearings so that the wheel will rotate about its horizontal axis 28, but is otherwise constrained against any linear movement.

In use as the auger rotates and moves into or out of the bore, the scraping wheel rotates about axis 28 either in a clockwise or anticlockwise direction depending on the movement of the auger. When the auger is boring, the soil (29, Figure 1) moves up the auger flight, to the point where the scraping wheel engages the flight. The soil that is moving up the auger is then blocked from further upward movement by the scraper 26 a-g then meshing with the flight and is scraped from the auger and collected by the chute 24.

When the auger is withdrawn from the bore the flight is often clogged up with excavated soil or other debris. To clean the auger it is counter-rotated (i.e. in the opposite sense to when it is boring) and the scrapers again dislodge the adherent debris from the flight.

It will be appreciated that in both the boring and withdrawal modes the scraping wheel meshes with the auger in a gear like manner and scrapes the debris from the flight as the auger rotates about its axis.

In a second embodiment of the invention, as shown in Figure 3, the scraping wheel may be replaced by an endless scraping chain 30. The scraping chain comprises a number of projecting scrapers 32a-32m which are attached to a caterpillar type tread 34 which rotates about freely rotatable idler wheels 36 and 38 detachably supported from the rig 18.

The linear pitch of the scrapers is the same as the helical pitch of the auger flights. Since the chain presents more scrapers to the flight than does the wheel 26 the scrapers together can project into and mesh with the auger flight over more than one pitch thereof. This allows the flight to be more thoroughly scraped. The scrapers occupy substantially the whole of the space between pitches of the flight, as already described for the Figure 2 embodiment.

Brushes (not shown) may be attached to the perimeters of the scrapers to aid cleaning of the flight, in either embodiment.

The freely-rotating mounting of the scraper wheel 22, and the freely-rotatable idler wheels 36,38 permit the auger to be moved longitudinally of itself with or without rotation, for example when the auger is to be vertically positioned before drilling, or if it is clean and merely has to be withdrawn from the bore. In such circumstances longitudinal movement of the auger is accommodated by rotation of the wheel 22, or of the chain 30 about its idler wheels, the auger flight then meshing with and driving the wheel or chain in the manner of a rack-and-pinion.

It will further be appreciated that the scrapers may be differently shaped as long as they may move in and out of engagement with the flight as the auger is moved, and the movement is such that the scraper does not cause them to impede rotation of the auger. For example the scrapers each may be in the form of a number of parallel tines rather than blades as illustrated.

Claims

1. A device for removing adherent material from a helical flight of an earth-boring auger or other screw-conveyor comprising scraping means adapted to scrape material from within the flight, and means movably mounting the scraping means so that it is adapted to project into the flight and effect said scraping during rotation of the flight.

2. A device according to Claim 1 or Claim 2, wherein the scraping means comprises a plurality of scrapers arranged successively to enter and leave the flight during rotation thereof.

3. A device according to Claim 1 or Claim 2, wherein the scraping means is in the form of a rotatably mounted wheel having a plurality of said scrapers thereon.

4. A device according to Claim 1 or Claim 2, wherein the scraping means is in the form of an endless chain, the scrapers being mounted on the links thereof.

5. A device according to any preceding claim, wherein the scraping means is movably mounted so as to accommodate longitudinal movement of the auger.

6. A device according to Claim 5 and either Claim 3 or Claim 4, wherein the wheel is mounted for free rotation or the chain is disposed around freely rotatable idler wheels.

7. A device according to any preceding claim, wherein the scraping means includes a brush adapted to clean a surface of the flight.

8. A device for removing adherent material from a soil-boring auger or other screw-conveyor substantially as described with reference to, and as shown in, the accompanying drawings.

9. Earth-boring equipment comprising an auger having a helical flight, or screw conveyor equipment having a helical flight for conveying adherent material, said equipment comprising a device according to any preceding claim.

10. Equipment according to Claim 9, incorporating a device according to Claim 2 and wherein the scrapers are spaced relatively to each other at a pitch such that they mesh with the flight.

11. Equipment according to Claim 10, wherein a scraper is shaped to occupy substantially all of the space between adjacent pitches of the flight in the plane of the scraper, except for clearances necessary for rotation of the flight and for engagement and disengagement of the scraper with the flight during meshing thereof.

12. An earth-boring auger or other screw-conveyor for adherent material substantially as described with reference to, and as shown in, the accompanying drawings.