Cake baffle disc

The cake baffle disc was patented more than 15 years ago by the then Pennwalt/Sharples company [7]. It has been variously known as the Lee disc (after the inventor), a BD disc, biological disc or a baffle disc. Together with a negative ring dam (pond level higher than the cake discharge) it was known 

The baffle di.sc comprises a plain disc welded to the conveyor hub somewhere between the feed zone and the cake discharge. On countercurrent decanters the usual location for the disc is at the foot of the beach. However, more recently, the disc has been seen situated in several positions on the beach from bottom to top. Ideally there should be a minimum distance, say one pitch, between the disc and the feed zone. This is to avoid turbulence from incoming feed at the periphery of the disc. 

The clearance between the tip of the disc and the conveyor outside diameter will be anything from a few millimetres up to about half of the pond 

The function of the disc is to form a seal with the scrolling cake to prevent the escape of feed or clarified liquor when the liquid level is higher than the cake discharge level. This technique is often used in the dewatering of effluent sludges. 

The baffle disc can experience considerable axial forces, and thus a substantial thickness needs to be used with good welding where it crosses the flight. In some instances a dog-leg is used where the disc is attached to the flight. This can produce unwanted paddling of cake, by virtue of the axial component of the dog-leg. 

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The baffle cone has the same function as the cake baffle disc. In place of the disc at the foot of the beach, a cone the full length of the beach or a shortened one at the foot is substituted. 

This disc is the same as the cake baffle disc but fitted close to the centrate discharge. It is only suited to the countercurrent decanter. 

The longitudinal baffle (9J perforins the same function as the cake baffle disc but in form Is a rectangular plate fitted, by welding, between two adjacent... 

In a dry solids decanter, there is generally a restriction, for example a baffle disc, against which the conveyor compresses the cake. Sometimes the cake discharge aperture forms the restriction or acts as an extra restriction in series... 

A disc built onto the conveyor hub to baffle scrolled cake. Also known as a cake baffle Baffle disc... 

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