Classifying – separating – and assorting solids – Sifting – Elements
Reexamination Certificate
1998-12-23
2001-06-26
Nguyen, Tuan N. (Department: 3653)
Classifying, separating, and assorting solids
Sifting
Elements
C209S390000, C209S672000
Reexamination Certificate
active
06250477
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a star scalper for separating supplied material, comprising a number of parallel, rotatable shafts that are each equipped with a number of star bodies placed at a distance from each other, which bodies have a hub and radially protruding star fingers, in which the star bodies of each shaft extend between the star bodies of the adjacent shaft.
Such a scalper is known and for instance meant for sifting waste, in which the waste has to be separated in a crude and fine fraction. There is a certain distance between the extremities of the fingers of the one star body on one shaft and the hub of the star wheels in between which the one star body has to rotate on the adjacent shaft, which distance together with the intermediate distance between two consecutive star bodies on the adjacent shaft determine a rectangular passage. Said rectangular passage is normative for the size of the objects which are let through by the star scalper. The star fingers of the star scalper move along each other with small intermediate distance. Usually the shafts of the star scalper all rotate in the same direction, so that the material moves over the scalper and the fraction which is left on the scalper is discharged. In this way it is also effected that an object which is too large for the passage will not block the passage, because in every passage a star body is present which makes an upward movement, so that the object is released.
A disadvantage of the known star scalper is that fine material into the fine fraction may cake onto the hubs of the star bodies, as a result of which the effective passage is made narrower. In this way the sifting effect of the star scalper is reduced after some time. The star scalper also has to be cleansed regularly.
It is an object of the invention to provide an improved star scalper.
SUMMARY OF THE INVENTION
This object is achieved according to the invention with a star scalper of the kind mentioned in the preamble, in which at least one star body is provided with a scraper, which scraper reaches to the hub of the adjacent star body.
In this way it is effected that at each revolution of the star body with the scraper, the hub of the adjacent star body is at least partly cleansed, as a result of which caking of dirt and silting up of the passage is prevented. Because there is less pollution, less engine power is necessary during sifting, the star scalper has to be cleansed less often and the sifting fraction remains more regular.
Preferably the scraper is arranged near the extremity of a star finger of the star body. In this way the scraper can remain small.
According to a preferred embodiment the scraper is at least as wide as the thickness of the star finger. In this way a large part of the adjacent hub is cleansed.
Preferably on one side of the star body the scraper continues until the star fingers of the adjacent star body. In this way these star fingers are at least partly cleansed as well.
According to a preferred embodiment each star body is provided with a scraper, in which way all hubs are kept clean.
Preferably all star bodies with scraper are identical, so that the star bodies can be economically manufactured.
Preferably per rotatable shaft the scrapers of the star bodies are placed in a jumped manner, so that the scrapers on one shaft do not scrape all at a time along the hubs of the adjacent shaft. In this way the load of the shaft is more regular.
According to a preferred embodiment the star fingers of the star body are flexible in axial direction. In this way the star fingers will not break off but be able to deflect when a hard object such as for instance a stone gets stuck in a slit between two consecutive star bodies.
Preferably shafts that are adjacent to each other are always rotatable with a different number of revolutions, as a result of which the entire circumference of the hub is kept clean by the scraper.
The invention also relates to a star body for a star scalper, comprising a hub with an aperture for attachment on a shaft of the star scalper and a number of radially protruding star fingers, in which at least one scraper is arranged to scrape along the hub of a star body on an adjacent shaft of the star scalper.
According to a preferred embodiment of the star body the scraper is arranged near the extremity of a star finger, and preferably the fingers of the star body are flexible in axial direction.
The invention will now be elucidated on the basis of a preferred embodiment, referring to the drawing.
REFERENCES:
patent: 3316977 (1967-05-01), Snook
patent: 4266676 (1981-05-01), Ruckstuhl et al.
patent: 5480034 (1996-01-01), Kobayashi
patent: 2751562 (1979-05-01), None
patent: 3926451 (1991-03-01), None
patent: 1240250 (1959-10-01), None
patent: 2313284A (1997-11-01), None
patent: 9002165 (1992-05-01), None
patent: 578920 (1977-11-01), None
patent: 1428237 (1988-10-01), None
Howard & Howard
Machinefabriek Lubo B.V.
Nguyen Tuan N.
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