Concrete block assembly

Claim 1

A concrete block drain line forming a drain field of a septic tank sewage disposal system comprising a plurality of identical porous concrete blocks oriented in end-to-end aligned and sealed relation, each block including a plurality of larger openings extending therethrough to form a plurality of longitudinal passageways for effluent flow and adapted to be interconnected at their ends, and tension means extending through small openings in the plurality of blocks for retaining the blocks in assembled sealed relation prior to installation in the drain field, said small openings being disposed symmetrically about the center of the blocks and between said large openings and adjacent the periphery of the block, said tension means being in the form of a plurality of tension rods extending through the small openings in each block with retaining nuts on each end of each rod, the ends of the rod and retaining nuts being received in recesses in the endmost blocks to enable adjacent, aligned assemblies to be disposed in adjacent relation for interconnection, said blocks being of square configuration with the large openings therethrough and small openings therethrough being symmetrically arranged to align the openings in different positions of the blocks relative to each other, said concrete block drain line being in the form of a module to be oriented in end-to-end, aligned relation to similar modules to form a drain field, and connecting means associated with the endmost blocks on said concrete block module, said connecting means including a recess in opposite side edges of the axially innerface of the endmost blocks of the concrete block module and retaining clips each having a portion received in the recess and on the tension rod and a portion extending laterally beyond the concrete block module with the projecting portion adapted to receive clamping bolts for securing the adjacent endmost blocks of two aligned concrete block modules in secure connected relation, each of said blocks in the concrete block drain line including recesses in both faces thereof to enable any of the blocks to be oriented as the endmost blocks and with either face of such blocks faced axially inwardly of the concrete block module.