MATERIAL CONVEYING AUGER

Abstract: A material conveying auger (14) comprising a first flight portion (17) for metering said material within a wide range of conveying rates dependent upon rotational speed of said auger, characterised in that, a second flight portion (18) starting at a mixing section (22) is provided downstream of said first portion (17) in the conveying direction, said second flight portion (18) having a plurality of interposed flights (20, 21) providing a plurality of entrances (23, 24) and exits respectively being equal to the number of said interposed flights (20, 21).

Description: MATERIALCONVEYINGAUGER The present invention relates to material conveying augers such as, for example, those used to meter and convey agricultural material. In many situations augers are required to convey _ 5 material at different rates which can be achieved within certain limits merely by changing the speed of rotation of the auger. However, in order to extend the limits of conveying rate it is necessary with existing technology to change the auger which, in many machines is not too 10 difficult to achieve, but the need to carry a range of different augers and the inconvenience in changing augers in a machine, creates problems which are time consuming and expensive. The augers may differ in flight pitch, flight depth and lead angle of flight. 15 Following on from this a further problem with existing augers occurs when they -are operated at slow speeds to provide a low conveying rate since an intermittent or pulsing output of the conveyed material may result particularly if the material being conveyed is- particulate 20 material of large particle size. In many instances this pulsing output is of no consequence but in others, such as for example, air seeding of crops, the pulsing can cause gaps or bare patches in the ultimate crop due to irregular seeding. Apparatus for air seeding of crops includes a 25 bulk supply storage bin for containing the seeds and a horizontal auger for conveying the seeds from the bin and depositing same into an air-stream. The air-stream then conveys the seeds to a number of distribution heads for distribution to various spaced outlets. It is thus importan 30 to avoid pulsing of the material from the auger into the air-stream and whilst this may be achieved in many instances jr by changing to an auger of shorter or finer pitch, in situations of large seed size this is often not possible as the seeds will not fit between the auger flights. 35 Accordingly it is an object of this invention to provide an improved material conveying auger adapted to convey material at a wide range of rates without causing an intermittent or pulsing outlet of material at the auger outlet as can occur with existing augers. Thus the invention provides a material conveying auger comprising a first flight portion for metering said material within a wide range of conveying rates dependent upon rotational speed of said auger, characterized in that, a second flight portion is provided downstream of said first portion in the conveying direction, said second flight portion having a plurality of interposed lights providing a plurality of entrances and exits in said second flight portion, the number of entrances and exits respec¬ tively being equal to the number of said interposed flights. In order that the invention may be more readily understood, one particular embodiment will now be described with reference to the accompanying drawings and in relation to an auger for conveying agricultural material from a bulk storage bin to an air-stream in an air seeding apparatus. In the drawings: Fig. 1 is a part sectional side elevation of the auger. Fig. 2 is a section on the line 2 - 2 of Fig. 1, and Fig. 3 is a section along the line 3 - 3 of Fig. 1. Referring now to the drawings the casing 10 of the apparatus, which is shown more or less schematically, in section defines a bulk supply bin 11 for containing granular agricultural material, a horizontal tubular portion 12 for conveying the material from the bin 11 and a vertical drop portion 13 for dropping the conveyed material into an air-stream. An auger 14 is arranged in the tubular portion 12 and is mounted on a shaft 15 accommodated in end bearings 16 at opposite ends of the tubular portion 12. The auger 14 comprises a first flight portion 17 and a second flight portion 18 which is arranged downstream of the first flight portion\17 in the direction of material being conveyed. The first flight portion 17 is forme from a single auger flight 19 and is adapted to meter the required quantity of material from the bin.11. The single flight auger 19 is therefore 5 a single start auger and the flighting pitch, lead angle and flight depth are designed to provide predetermined metering rates within limits which may be extended at the lower end of the range as compared with existing augers. In other words with low conveying rates the auger 14 is rotated at 10 a slow speed and whilst this may cause an intermittent or pulsing output from the first flight portion 17 this will be overcome by the second flight portion 18 as will be apparent hereinbelow. The second flight portion 18 is formed from two 15 separate auger flights 20 and 21 respectively. The start and finish of the flight 20 can be seen in the drawings whereas the start and finish of the flight 21 are not evident in the drawings as they occur on the other side of the auger. The flight 21 is in fact a continuation of 20 the flight 19 of the first flight portion 17. A mixing section 22 is defined between the first and second flight portions. The mixing section 22 allows a certain accumula¬ tion of material from the first flight portion 17 and ensures that substantially equal quantities of material 25 are picked up by the auger flights 20 and 21. For this purpose, the leading or upstream end of the flight 20 has a greater lead angle than the remainder of the flight or continues on to a point close to the first flight portion 17 to define an entrance 24 which is narrower than the 30 entrance 23 of the other start portion of the double start flighting. It will be appreciated that material conveyed *r by the first flight portion 17 tends to be compressed * against the last turn of the first flight portion 17 and thus there is a tendency for a greater amount of material 35 to enter the start or entrance 24 than would enter the start or entrance 23 if they were of equal width. Thus by arranging the dimensions appropriately a substantially equal quantity of material will enter both the starts or entrances. Naturally the lead angle of the second flight portion in an overall sense is greater than the lead angle of the first flight portion in order to accommodate the two separate auger flights. At the downstream end of the second flight portion 18 the auger flights 20 and 21 cease well before the end of the auger. In other words there is a space in the downstream end of the tubular portion 12 after the end of the second flight portion 18 and before the vertical drop portion 13. This further enhances the operation of the apparatus by ensuring that material delivered by the separate auger flights 20 and 21 is able to form into a substantially continuous stream before entering the drop portion 13. It should be evident that the second flight portion 18 provides a consistent feed section since the double entrance - double exit ensures a greater frequency of delivery of material at the outlet end. Clearly .the auger of the invention may be constructed either by fabrication or moulding in whatever material is appropriate to the particular purpose to which the auger will be used. According to the embodiment the -material is a plastics material. It should be evident from the embodiment describe herein that the present invention provides an improved composite type metering auger for conveying material of all kinds. Whilst the downstream portion of the auger has two separate flights it is clear that three, four or possibly even more interposed flights could be provided in the downstream portion although as the number increases practica limitations arise. It is also conceivable that the flights of the second flight portion 18 could both be separate and distinct from the flight of the first flight portion 17. The invention provides an auger which is parti¬ cularly but not exclusively adapted for use in air seeding apparatus for agricultural material where the auger drops the material into an air-stream. The invention extends the range of operation by greatly facilitating low speed or low volume conveying without causing an intermittent or pulsing output of material which would result in irregular seeding. At low conveying speeds the first or upstream auger portion provides a metering function whereby the required flow rate of material occurs from the bulk supply bin. Whilst at these low flow rates an intermittent or incon- sistent flow may occur in the first auger portion this is obviated by the second or downstream flight portion. Whilst in some instances the same result may possibly be achieved by replacing a higher volume (large pitch) auger with a low pitch auger and operating at a higher speed, it still neces- sitates the inconvenience of the change-over operation and in any case, in many instances the physical size of the seeds prevents this alternative as a means of avoiding pulsing as the seeds will not fit between the auger flights. The present invention has been found most suitable for air seeding at low planting rates (2 - 200 lb/acre) with all types or sizes of seeds as well as being suitable at high planting rates. The need to change augers is thus obviated and the inconsistent or intermittent output at low speeds is avoided.

Claims: CLAMS - 6 - 1. A material conveying auger comprising a first flight portion for metering said material within a wide range of conveying rates dependent upon rotational speed of ' said auger, characterized in that, a second flight portio is provided downstream of said first portion in the conveyin direction, said second flight portion having a plurality of interposed flights providing a plurality of entrances and exits in said second flight portion, the number of entrances and exits respectively being equal to the number of said interposed flights. 2. A material conveying auger as defined in claim 1 characterized in that, a mixing section is provided between said first and second flight portions. 3. A material conveying auger as defined in claim 2 characterized in that, said first flight portion is a single flight portion. 4. A material conveying auger as defined in claim 3 characterized in that, the number of flights in said second flight portion is two thus providing a double start flighting. 5. A material conveying auger as defined in claim 4 characterized in that, one of the flights of said second flight portion is a continuation of the flight of said first flight portion. 6. A material conveying auger as defined in claim 5 characterized in that, the other of the flights of said second flight portion has its start or upstream end arranged closer to the first flight portion than to the other flight of said second flight portion such that the said entrance closest to said first flight portion is narrower in width than the other said entrance causing substantially equal quantities of said material to enter each of the respective entrances. 7. * A material conveying auger as defined in claim 6 characterized in that, the pitch and lead angle of said double start flighting is predetermined for even and con¬ sistent dispatch of said material at said exits. 8. A material conveying auger as defined in claim 7 characterized in that, said second flight portion ends short of the downstream end of said auger. OMPI

Inventors: MCKAY MALCOLM ERNEST, WOODWARD JOHN WILLIAM
Applicants: GASON PTY LTD A F, MCKAY MALCOLM ERNEST, WOODWARD JOHN WILLIAM
Application year: 1981
Main classification: A01C7
IPC codes: A01C7, B65G33, B65G65