Imperforate bowl: centrifugal separators – Rotatable bowl – Including driven material-moving means therein
Patent
1998-06-09
2000-02-15
Cooley, Charles E.
Imperforate bowl: centrifugal separators
Rotatable bowl
Including driven material-moving means therein
B04B 120
Patent
active
060246863
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a decanter centrifuge for separation of a material supplied into a light phase and a heavy phase.
DESCRIPTION OF THE RELATED TECHNOLOGY
Decanter centrifuges generally have an elongated bowl adapted for rotation about its longitudinal axis, a screw conveyor arranged in the bowl and coaxial therewith and comprising a body carrying a screw, inlet ports in the screw conveyor for supply of the material to be separated, and discharge ports for the heavy phase in the bowl at one end of the conveyor, the screw conveyor being adapted to rotate in relation to the bowl for transporting the heavy phase towards the discharge ports for the heavy phase, and a baffle which is arranged between the inlet ports and the discharge ports and the radial extent of which in any axial position is smaller than the radial extent of the screw in the same axial position, the baffle extending from a position on the side of a flight of the screw of the conveyer facing towards the discharge ports to a position on the side facing away from the discharge ports of one of the flights of the conveyor screw following in the direction towards the discharge ports, without intersecting an intermediate flight.
U.S. Pat. No. 3,885,734 describes a centrifuge of this type, which has a baffle in the form of an annular disc arranged at right angles to the longitudinal axis of the conveyor. The baffle functions as a barrier preventing the light phase from moving towards the discharge openings for the heavy phase. With this barrier the decanter can be operated with unequal liquid levels on the light phase side and the heavy phase side of the baffle disc.
In the decanting process, the heavy phase is transported by the screw conveyor from the separation chamber constituted by the space between the inner surface of the bowl and the outer surface of the body of the conveyor, to the discharge ports for the heavy phase, and the baffle disc causes a reduction of the cross-sectional area available for this transport. Depending on the consistency and the quantity of the heavy phase, this restriction may result in an undesired large accumulation of heavy phase product on the light phase side of the baffle disc and create impaired inlet and separation conditions and in addition increase wear on the decanter as well as require a higher torque to maintain the relative motion between the conveyor and the bowl.
U.S. Pat. No. 3,934,792 describes a decanter centrifuge of the above mentioned type having a baffle generally in form of a flat, radial plate located across the helical chamber bounded by two adjacent screw flights, the outer surface of the conveyor body and the inner surface of the bowl. This baffle has the same disadvantages as the baffle known from U.S. Pat. No. 3,885,734 and because of its short length it reduces the cross-sectional area available for transport of the heavy phase to the discharge ports even more than the above mentioned prior art baffle. The baffle has a further disadvantage in that it does not have the same hand as the screw conveyor and therefore counteracts the transporting effect of the flights of the screw conveyor.
SUMMARY OF THE INVENTION
It is the object of the invention to provide a decanter centrifuge in which these disadvantages are reduced or completely eliminated.
According to the invention this is obtained in a decanter centrifuge of the type mentioned in the introduction in that the baffle takes the form of a helical rib having the same hand as the screw conveyor.
As the baffle is shaped like a helical rib handed in the same direction as the conveyor screw, it actively contributes to transporting the heavy phase towards the discharge openings in the same way as the screw, whereby the accumulation of the heavy phase on the upstream side of the baffle is reduced, the effect of which is that the disadvantages described above, caused by the accumulation, are reduced or completely eliminated. The baffle according to the invention has the added advantage that the transpor
REFERENCES:
patent: 3289926 (1966-12-01), Hiller et al.
patent: 3885734 (1975-05-01), Lee
patent: 3934792 (1976-01-01), High et al.
patent: 4245777 (1981-01-01), Lavanchy
patent: 4303192 (1981-12-01), Katsume
patent: 4378906 (1983-04-01), Epper et al.
patent: 4731182 (1988-03-01), High
patent: 5509882 (1996-04-01), Caldwell
patent: 5643169 (1997-07-01), Leung et al.
patent: 5653673 (1997-08-01), Desai et al.
Alfa Laval Separation A/S
Cooley Charles E.
LandOfFree
Decanter centrifuge with helical-rib baffle does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Decanter centrifuge with helical-rib baffle, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Decanter centrifuge with helical-rib baffle will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1901725