Abstract: A plurality of coaxially arranged, nested tubes (1, 2, 3, 4) are retained between distributor heads (8, 45). The heads and the outermost tube (1) are coupled to one another in a media-tight manner by fitting flanges to provide releasable axial connections. Each distributor head (9, 45) has two walls (9, 10, 46, 47) concentric to one another as well as one end chamber (17, 50) communicating with an annular chamber (11, 48, 49) formed between the walls. The outer wall (9) is joined to the outer tube (1), and the second tube (2), located inside the outer tube, is inserted into the inner wall (10) against an axial stop (24). A sleeve (26, 58, 59) is connected to a third, inner tube (3) located inside the second tube (2). The sleeve (26) is also braced against an axial stop (28) of the inner wall (10) close to the end chamber. The interior (34) of the sleeve communicates via an opening (19, 55) with the end chamber (17, 50).

Abstract: A method of concentrating grape juice to a predetermined final degree of concentration comprises the steps of evaporating one part of the water content of the grape juice to obtain an intermediate degree of concentration less than the final degree of concentration, then stabilizing the grape juice for cream of tartar by cooling the grape juice to near freezing temperature; and thereafter resuming evaporation of water of the grape juice for ultimately reaching the final degree of concentration.

Abstract: A spiral heat exchanger includes a vessel, a plurality of concentric sheet metal spirals situated in the vessel and defining first and second spiral flow channels for respective first and second fluids for effecting a heat exchange therebetween; first and second closure plates extending perpendicularly to the vessel axis and covering the spirals at opposite spiral edges thereof; and mounting bars pressing the closure plates against axially opposite edges of the spirals. The first closure plate defines a first axially oriented opening and the second closure plate defines a second axially oriented opening providing, in the first flow channel, an inlet and an outlet for the first fluid. The vessel comprises a cylindrical vessel shell entirely surrounding the spirals.