A roller compactor is a well known densification and dry granulation machine for powdered material. The roller compactor produces uniform compacted sheets from powder, with consistent hardness and increased density. The roller compactor compacts powdered material between two rollers under pressure. The compacted powdered sheets can then be used for manufacturing free flowing granules for automatic packaging of products, compact granules for reduced product packing sizes, and granules for high speed tableting or encapsulation, with consistent dust-free purity and size.
In a conventional roller compactor machine, powder material is fed into a hopper and is pre-compacted with a screw feeder in the hopper. The screw feeder than delivers the powder to the rollers. The screw feeder normally is either a fully straight screw or a fully tapered screw, both of which have advantages and disadvantages. A fully straight screw enhances even distribution of the powder onto the compacting rollers. A fully tapered screw enhances pre-compaction and de-aeration of the powder within the hopper.
It is desirable to have a roller compactor machine having the benefits of both the straight screw and tapered screw.
Accordingly, a primary objective of the present invention is the provision of a roller compactor machine having an improved screw feeder.
Another objective of the present invention is the provision of a screw feeder for a roller compactor machine wherein the screw has both a tapered section and a straight section.
A further objective of the present invention is the provision of an improved screw feeder for a roller compactor machine wherein the screw has a tapered shaft and a straight shaft, with constant depth flighting on the shafts.
Still another objective of the present invention is the provision of an improved screw feeder for a roller compactor machine which is economical to manufacture, and durable and safe in use.
These and other objectives will become apparent from the following description of the invention.
An improved screw feeder is provided for a roller compactor machine. The screw feeder is mounted inside the hopper of the machine, and has an upper tapered section and a lower straight section. The tapered section has opposite upstream and downstream ends, with a tapered shaft narrowing from the upstream end to the downstream end. The straight section of the screw feeder has a straight shaft. Auger flighting extends along the tapered shaft and straight shaft, and has a constant depth or width along the length of the screw feeder.
A roller compactor machine is generally designated in the drawings by the reference numeral 10. The machine 10 includes a hopper 12 with a screw feeder 14 therein to feed powdered material from the hopper 12 to a pair of compacting rollers 16.
The machine 10 includes a drive train for the screw feeder 14 and a drive train for the compacting rollers 16. The respective drive trains generally include motors 18, 19, speed reducers 20, 21, flex couplers 22, 23, and gear box 24, and drive shaft 25. The drive trains are conventional and do not constitute a part of the present invention.
The present invention is directed towards the screw feeder 14. The screw feeder 14 includes an upper hub 26 which is operatively connected to the gear box 24 via a coupler 28. Actuation of the screw feeder drive train turns the screw feeder 14 via the coupler connection between the gear box 24 and the screw feeder 14.
As best seen in
In use, the tapered section 34 of the screw feeder 14 pre-compacts and de-aerates the powder within the hopper 12. The straight section 32 of the screw feeder 14 evenly distributes the powder across the faces of the compacting rollers 16. If desired, a scraper, such as a multi-sided star shaped scraper, can be provided on the lower end of the straight section 32 of the screw feeder 14 to further enhance the distribution of powder across the faces of the rollers 16.
The invention has been shown and described above with the preferred embodiments, and it is understood that many modifications, substitutions, and additions may be made which are within the intended spirit and scope of the invention. From the foregoing, it can be seen that the present invention accomplishes at least all of its stated objectives.
Number | Name | Date | Kind |
---|---|---|---|
3269611 | Komarek | Aug 1966 | A |
3781151 | Harris | Dec 1973 | A |
3938434 | Cox | Feb 1976 | A |
4111626 | Funakoshi et al. | Sep 1978 | A |
4415336 | Stasi | Nov 1983 | A |
4871449 | Lott | Oct 1989 | A |
5122263 | Huber | Jun 1992 | A |
5558433 | Gheorghita | Sep 1996 | A |
6513424 | Iwasaki | Feb 2003 | B1 |
Number | Date | Country |
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0 554 964 | Aug 1993 | EP |