Foam insulated prestressed concrete wall

Claim 1

A HEAT INSULATING WALL FOR DIGESTER TANKS AND THE LIKE, COMPRISING A CONTINUOUS METAL DIAPHRAGM IN THE FORM OF AN UPRIGHT-CYLINDRICAL ENCLOSURE HAVING VERTICAL STIFFENING CORRUGATIONS ON ITS SURFACE, CONCAVE AND CONVEX WALLS OF CONCRETE ENCLOSING THE CORRUGATED METAL DIAPHRAGM BETWEEN THEM AND PRESENTING SUBSTANTIALLY SMOOTH AND CONTINUOUS CYLINDRICAL SURFACES, SEPARATE RECTANGULAR SLABS OF HEAT-INSULATING ELASTOMERIC FOAM CONFORMED TO THE OUTER CYLINDRICAL SURFACE OF THE CONVEX CONCRETE WALL AND AFFIXED THERETO IN CIRCUMFERENTIAL SPACED RELATION, AN OUTER CONCRETE WALL ENCASING SAID ELASTOMERIC SLABS AND BEING BONDED TO THE CONVEX CONCRETE WALL IN THE SPACED AREAS BETWEEN THE SLABS, PRE-TENSIONED WIRE WRAPPED IN CONTINUOUS CIRCULAR BAND ABOUT THE OUTER CONCRETE WALL SO AS TO HOLD UNDER COMPRESSION THE ENTIRE WALL STRUCTURE INCLUDING THE ELASTOMERIC SLABS, AND A COVER LAYER OF CONCRETE ENCASING SAID WIRES.