Abstract: Stripping of volatile substances from less volatile fluids as in the deodorisation and steam refining of fats and oils in an elongate conduit (1) in which the rate of flow of stripping gas is accelerated by having it emerge from a constriction (5;18) to which an inlet (6;20) for liquid feed material is operatively connected is achieved by having the path for food material downstream of the constriction (5;18) provided at intervals with inclined baffle surfaces (8) extended in the flow direction of the path across part of the cross-section thereof to project back into the gas within the path liquid film which has accumulated on the wall of the path.

Abstract: A scraped surface heat exchanger comprises a pair of concentric heat exchange tubes. A heat exchange medium passes through the annular chamber between the tubes and a fluid, in particular one whose viscosity increases as it passes through the heat exchanger and whose temperature is to be modified by heat exchange with the heat exchange medium in the annular chamber, passes through the inner of the tubes. A helical scraper blade arrangement extends along the length of the shaft within the inner chamber. The scraper blade arrangement comprises one or more thin plastics or metal blades set within a helical slot which is angled against the direction of flow of the fluid medium and makes with the internal surface of the inner tube a contact sufficient to allow the blade arrangement to rotate within the inner tube when conveying through it the fluid whose temperature is to be modified.