Apparatus for making biological discs

Apparatus for forming a circular water-treatment biological disc comprising:

• a support means for supporting a pair of substantially identical, rectangular flat plastic sheets of material in side by side relation, the rectangular sheets having adjacent longitudinal edges thereof disposed in overlapped relation,
• a heating mechanism engageable with the adjacent overlapped longitudinal edges of the pair of plastic sheets to simultaneously heat the longitudinal edges to a predetermined temperature,
• a compression assembly for compressing the overlapped heated longitudinal edges of the sheets to thereby heat seal the edge portion together and form the two sheets into a single large sheet,
• a vacuum forming device including a horizontally disposed vacuum forming structure, having a plurality of upwardly convex elements and a plurality of downwardly opening concave recesses throughout the area of said vacuum forming structure, clamping means connected with the peripheral portions of said vacuum forming structure and being operable to releasably clamp the peripheral portions of the sheets on the vacuum forming structure,
• a volumetric vacuum zone defined between the clamped sheet and the vacuum forming structure when the former is clamped to the latter, means connected with a vacuum zone for evacuating air therefrom,
• a heating mechanism shiftable into close proximity of the vacuum forming device for heating the sheet when the latter is clamped upon the vacuum forming structure,
• a cutting apparatus positioned closely adjacent the vacuum forming device including a supporting frame, and a cutting mechanism mounted adjacent said frame and adapted to be rotated on a predetermined radius for cutting the sheet into a disc form.