Investment casting shell mold drying and desiccant reactivation apparatus

Claim 2

Apparatus for desiccant drying investment casting shell molds and reactivating the desiccant comprising, an elongated drying tank containing a fluidized bed of desiccant, conveyor means for supporting and transporting expendable patterns dipped in slurry or slurry and stucco through the desiccant bed, and means continuously taking desiccant from the bed, reactivating the desiccant, and returning it to the bed.

Claim 3

Apparatus as defined in claim 1, wherein said last-named means includes a reactivator for receiving desiccant from the bed and applying heat to remove water therefrom, and a cooling tower for receiving desiccant from the reactivator and cooling same before returning it to the bed.

Claim 4

Apparatus as defined in claim 2, wherein said last named means includes a funnel-shaped member and conduit for taking desiccant from the tank, said tank including a defuser plate for supporting the desiccant and means forcing air upwardly therethrough, said funnel-shaped member including a large open end facing the defuser plate and in slightly spaced relation therefrom to define an opening with the plate through which desiccant passes to a point below the funnel, and a necked end connected to the conduit, wherein the funnel traps air to drive desiccant through the conduit.

Claim 5

Apparatus as defined in claim 3, wherein the reactivator includes an elongated upstanding tube terminating in an upper open end, a hot gases inlet at the lower end of the tube, means producing and driving hot gases into said hot gases inlet, a desiccant inlet in the tube spaced upwardly from the hot gases inlet, a compressed air inlet in the tube spaced intermediate the hot gases inlet and the desiccant inlet, a hopper defining a collecting chamber mounted on the upper end of the tube so the upper open end is arranged within said chamber, a cover on said hopper having a screened opening, a bottom wall in the hopper supporting regenerated desiccant, said bottom wall being at an angle, and a discharge opening for the hopper at the lower end of the bottom wall to permit gravitational discharge of desiccant.

Claim 6

Apparatus as defined in claim 4, wherein the cooling tower includes an upstanding body having a desiccant receiving chamber and an air chamber separated by a defuser plate upon which is supported a bed of desiccant, an inlet to the desiccant chamber connected to the reactivator, means for supplyiNg compressed air to the air chamber to force air upward through the plate, a funnel in said desiccant chamber having a large open end resting on the defuser plate and an opposing necked end connected to conduit leading from the tower, openings in said funnel through which desiccant falls to the inside of the funnel, and a screened opening in the upper end of the tower to permit communication between the desiccant chamber and atmosphere, wherein the compressed air fluidizes and cools the desiccant in the desiccant chamber and forces desiccant within the funnel through the conduit.

Claim 7

Apparatus as defined in claim 5, wherein said conveyor means includes a continuous track for transporting the expendable patterns with coatings between coating and drying stations.