GB459459A - A process and apparatus for desiccating or drying liquid films - Google Patents

Abstract

<PICT:0459459/III/1> <PICT:0459459/III/2> In the evaporation of fruit juice, milk, yeast cellulose and other liquid films on supporting surfaces by means of rapid gas currents, the gases are caused to impact directly against the film on the supporting surface and are mainly returned immediately from the film by deflection therefrom. As applied to a drum dryer in which the liquid is fed on to the drum 1 from a sprayer 8 and the dried material removed by a scraper 9, the gas currents issue from alternate channels 6<1>, of cross-section diminishing towards the drum, and deflect into the intervening channels 5, the former channels communicating with a pair of gas supply ducts 4, Fig. 4, arranged as concentric annuli at each end of the drum, and the latter channels communicating with an outlet pipe 10 offset at right angles thereto. The channels are formed by a number of radially disposed walls 6, 7 occupying the space between the gas supply annuli 4, the whole being enclosed by a housing 3 concentric with the drum. The channels 6<1> are closed at their upper ends by walls 12 and 11<1> and the channels 5 are closed at their sides by walls 11, 11<1>. The channels 5 may be subdivided by means of a central wall disposed at right angles to the drum axis. In a modification, the annuli 4 are arranged as gas supply and withdrawal ducts respectively, the outlet pipe 10 being dispensed with. In this modification, a cylindrical cover encloses all the upper ends of the channels. Drying air may be sucked through the apparatus by means of a fan in the outlet pipe and the drum may be heated. The supporting surface may be plane or curved other than cylindrically and may be stationary.