Conveyors: fluid current – With diverse power-driven conveyor – Rotary
Patent
1997-06-27
2000-09-26
Ellis, Christopher P.
Conveyors: fluid current
With diverse power-driven conveyor
Rotary
406 67, 406135, 222237, 222240, 222370, B65G 308, B65G 5340, G01F 1120, G01F 1110
Patent
active
061234869
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to an apparatus for metering bulk material into at least one conveying line.
BACKGROUND OF THE INVENTION
So-called rotary vane feeders are known in general as metering apparatuses, with the aid of which bulk materials can be transferred out of an area at any pressure into a conveying line against a higher or lower pressure prevailing in the latter.
A cell wheel, seated in a rotationally fixed manner on a horizontal shaft, comprises a hub and radial vanes which, accordingly, bound wedge-shaped or trapezoidal chambers. The bulk material passes into at least one cell-wheel chamber, via a top charging opening, and after a rotation, for example through approximately 180.degree., is passed into a conveying line via a discharge opening, if appropriate, assisted by compressed air. It is usually the case that the quantity of bulk material which is metered in this way, first of all, rises as the rotational speed of the cell wheel increases and, as the rotational speed continues to increase, decreases again on account of the centrifugal force. Problems arise here in the case of sluggishly flowing, adhering and bridge-forming bulk materials since the relatively narrow inlet cross sections of the design hinder continuous filling of the cell-wheel chambers.
Furthermore, a mass flow, i.e., uniform discharge via the entire cross section of the storage container, is desired. If the material which is located in the center of the container is emptied more quickly than the material in the wall region, then incomplete emptying and regular filling of the storage container may result in the situation where it is only the material from the center of the container which is ever removed, and the material in the border region becomes old.
In order to achieve a high metering capacity even for sluggishly flowing bulk materials and to ensure the desired mass flow, the practice has thus been adopted, for example, German Offenlegungsschrift using a metering apparatus according to DE 34 25 895, of connecting to the cell wheel in a rotationally fixed manner a stirrer which extends upwards through the charging opening. This has improved the metering of sluggishly flowing bulk materials for certain metering capacities. In particular, in the case of a relatively low metering capacity, however, a stirrer of this type does not operate reliably.
SUMMARY OF THE INVENTION
The object of the invention is thus to propose a metering apparatus which operates reliably even in the case of very sluggishly flowing bulk materials, in particular with a small metering capacity, i.e., with the cell wheel rotating slowly.
An apparatus according to the invention is distinguished by two different, isolated drives being provided for the stirrer and the cell wheel.
In this way, the stirrer can be operated at a rotational speed which is independent of the rotational speed of the cell wheel. The rotational speed of the stirrer may, in particular, be coordinated with the flow behavior of the respective bulk material. At the same time, it is possible to use the entire cell-wheel rotational-speed range in which metering is possible for the purpose of controlling the metering capacity.
Typical rotational speeds-of the cell wheel are from 30 to 35 revolutions per minute with a regulating range of from 1 to 15. With a rotational speed of 30 revolutions per minute, this regulating range corresponds to a rotational-speed interval of from 2 to 30 revolutions per minute. In particular, in the case of starting-up operations, however, a very much lower degree of metering is required, so that it is also possible to activate speeds of 2 revolutions per minute. However, a stirrer of the prior art does not operate reliably at such low speeds.
The optimum rotational speed of the stirrer for loosening purposes and for achieving optimum flow properties depends to a great extent on the material in each case. A typical value is approximately 7 to 8 revolutions per minute.
By virtue of the invention providing two different drives, the st
REFERENCES:
patent: 2280166 (1942-04-01), Sinden
patent: 4712716 (1987-12-01), Schloz et al.
patent: 5007564 (1991-04-01), Beth et al.
patent: 5324142 (1994-06-01), Haig
Vogelsang Franz Josef
Wilms Harald
Bower Kenneth W
Ellis Christopher P.
Kinberg Robert
Spencer George H.
Zeppelin Schuttguttechnik GmbH
LandOfFree
Apparatus for metering bulk material does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for metering bulk material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for metering bulk material will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2094695