(57) rocess for reducing strongly the drying time of ceramics, even of considerable weight,
consisting in effecting drying in a single room in three stages, the first by supplying
heat to a static or slightly ventilated ambient at room temperature; the second by
placing the dryer under a vacuum of about 380 Torr so as to cause highly turbulent
air to be introduced in the ambient; the third stopping air inlet and increasing vacuum
up to about 45 Torr; or as a variant, carrying out drying in two separate rooms and
in two stages: the first by supplying heat to a heated and highly ventilated ambient
at room pressure; the second in an ambient where a vacuum of about 60-45 Torr is created
Means for carrying out the process according to the first system, consisting in putting
the interior of a static drying oven of known type in communication with one or more
vacuum pumps, and arranging inside the oven along its walls, at intervals, a set of
pipes provided along their length with a set of injection nozzles oriented on said
pipes, in such a way that those of a pipe are blowing opposite to those of the pipes
arranged in front and aside said pipe, respectively, so as to create a strong turbulence,
said pipes being connected through manifolds with the external environment from which
air is sucked only by vacuum produced in the oven.
Means for carrying out the process according to the variant, consisting in placing
the material firstly in a tunnel of known type, inside which there are, for each group
of materials, means blowinq hot air in the form of a blade and means for moving back
and forth the blowing means in respect of the group of products to be dried, or the
groups of products in respect of the blowing means, for the time required to the stage
in which to drying of the products corresponds also a material shrinkage, and then
a second tunnel provided with heat radiating walls and with the interior communicating
with one or more vacuum pumps so as to effect final drying without shrinkage.
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