A method and apparatus for determining load unbalance in an appliance is provided for an appliance having a vessel configured to receive a supply of material and rotatable about an axis. At least one steam feed hole extends angularly from a radially outermost face of the segment to a location along a side of the center portion such that, in use, at least a portion of the feed hole is exposed to hot gas in the hot gas path for flow through the feed hole to a cavity behind the segment. A sensor assembly is configured to provide an output signal indicative of position, displacement, velocity andor acceleration of the vehicle on the belt with respect to at least one reference axis. As a result, loss ascribable to the tail current is reduced. A flow path is also present for a fluid through the first impermeable metal layer. The scalable frame includes multiple linkages interconnected to one another in a manner that allows the frame to be folded into a relatively compact configuration for storage andor transport.