Harvesters – Motorized harvester – Including driven air-blower unit
Patent
1993-11-23
1995-07-04
Buiz, Michael Powell
Harvesters
Motorized harvester
Including driven air-blower unit
460 98, A01D 4500, A01F 1200
Patent
active
054289459
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a cleaning device for harvester-threshers and more particularly to means for guiding air flow produced by a radial-flow fan.
BACKGROUND OF THE INVENTION
The structure of known cleaning devices for the grain in harvester-threshers provides a fan, to which an air guiding device is connected on the discharge side, by which means the air stream generated by the fan can be purposely guided to the sifting arrangement.
The use of a cross-flow fan for the cleaning device of a harvester-thresher is shown in German patent document EP-OS 0 385 107. The cross-flow fan consists of a broad, drum-shaped rotor of radial structural form having numerous forward-curved vanes on the housing shell. The suction flow as well as the discharge flow of the fan are transverse to the axial direction of the fan housing. The cross-flow fan used in the harvester-thresher extends over the entire width of the sifting arrangement.
This design of fan has the disadvantageous property that contaminants or grains entering the housing of the cross-flow fan are not automatically discharged. In this way, there is a functional influence due to flow losses, with the consequence that the efficiency of the cleaning device in cross-flow fans installed in harvester-threshers can be detrimentally influenced.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the invention to provide measures in the discharge flow region of a cross-flow fan used in the harvester-thresher in order to permit a uniform fan stream independent of the position of the cross-flow fan and further to prevent the entry of foreign bodies into the cross-flow fan.
On the basis of a cleaning device of the type previously explained in more detail, for the achieving of the stated object, the air guiding device of a cleaning device of a harvester-thresher is provided with air guiding profiles, which effect a purposeful separation edge of the air stream in order in this way to prevent penetration of grains or other undesired particles into the air guiding device. The measures in accordance with the invention serve to equalize the blowing profile, referred to the total cross section of the air guiding device, by which means differences in the flow velocity can be reduced to .+-.2 m/s. The uniform distribution of the air flow has the further advantageous consequence that the downstream sifting device receives a uniform incident flow. The device in accordance with the invention, installed in harvester-threshers having a cross-flow fan, advantageously insures the discharge of grains from the air guiding device, since grains preferentially enter the air guiding device when the harvester-thresher is going down a slope as well as when the harvester-thresher is operated in a tilted position. To this end, the air guiding profiles in accordance with the invention purposely divert the air stream into the zones via which the grain preferentially passes from the cleaning device into the air guiding device.
In a development of the invention, the air guiding profiles are made wedge-shaped, by which means the desired separation edge of the flow can advantageously be strengthened in order to establish a turbulent flow.
A further idea of the invention provides for splitting the air stream by means of an air guiding profile in the air guiding device, which is designed as a diffuser, in order in this way purposely to bring about incident flow against the lower screen and the upper screen of the downstream sifting arrangement. To this end, the air guiding profile, which connects the two side faces of the diffuser, is advantageously arranged in such a fashion that the diffuser is split into two equal cross-sectional areas. The air guiding profile installed in the central zone of the diffuser in coincidence with the installed position of said diffuser exhibits a wedge-shaped cross-sectional profile, the wedge shape extending from the cross-flow fan up to half the length of the air guiding profile, downstream of which there follows a rectangular cross section;
REFERENCES:
patent: 4208858 (1980-06-01), Rowland-Hill
patent: 4465081 (1984-08-01), Decoene et al.
patent: 4475561 (1984-10-01), Decoene et al.
Fichter Rolf
Gansel Rainer
Honl Josel
Roth Hans W.
Schips Karl
Buiz Michael Powell
Klockner-Humboldt-Deutz AG
Schwab Charles L.
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