Two embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which: FIG. 1 is a longitudinal vertical section through a tubular double drum type washing machine according to the invention; FIG. 2 is a top plan view, partly in section, of the washing machine; FIG. 3 is a section taken on the line IIIIII of FIG. 1; FIG. 4 is a section t