The vacuum dryer of this invention is to include a drum which may be rotatably
mounted on a plurality of low frictional rollers which are mounted on a frame. Support may also be facilitated by mounting the end of the shaft of rotation in a low-friction bearing assembly. The material to be dryed is to be placed within the drum. The drum is essentially air tight. The drum is rotatable about a first axis. A swash plate, (or wobble plate) is rotatably mounted about a second axis. The second axis intersects the first axis and is inclined in respect thereto. A plurality of conduits are connected to the drum and each are connected through a bellows assembly to the swash plate. Each conduit is capable of extracting air and moisture particles from the internal chamber and discharging such into the ambient. Associated with each bellows assembly and conduit are two one-way valve assemblys. The bellows for each conduit is located between each of a pair of spaced-apart one-way valves for each bellows-conduit assembly. Motor means is provided to cause rotation of the drum and also the swash plate.
Previous attempts at designing a vacuum dryer apparatus have resulted in a substantially complexly constructed structure. Such a structure is difficult to manufacture, costly to manufacture and requires an increased amount of maintenance than conventional dryers.
Referring particularly to the drawing, there is shown the vacuum dryer 10 of this invention which is composed basically of an exterior housing 12 within which is contained the vacuum dryer operating structure 14 of this invention. The structure 14 is mounted on a rectangularly shaped metallic frame 16 which is attached to the inner surface of the exterior housing 12.
A second major application for a vacuum dryer facilitated dryer is the drying of foodstuff material, especially fruit and vegetable rind and pulp. These materials are very suitable for animal feeds and supplements when dried. In the wet state they are too heavy to transport and process and are prone to decay. Present thermal-drying techniques are cost-prohibitive at the low temperatures that would be required to avoid material breakdown.