Conduit for pneumatic conveying systems

Claim 1

A PNEUMATIC CONVEYING CONDUIT MEMBER OF THE CHARACTER DESCRIBED FOR CONVEYING THERETHROUGH PLASTIC PELLETS ENTRAINED IN A STREAM OF AIR AND SUSCEPTIBLE TO ABRADING CONTACT WITH THE INNER WALL SURFACE OF SAID CONDUIT, WHICH COMPRISES A GENERALLY TUBULAR CONDUIT HAVING AN INNER WALL SURFACE FOR ENCLOSING AND CONDUCTING SAID PARTICLES AS ENTRAINED IN SAID AIR STREAM, INTERNAL GROOVES IN SAID INNER WALL SURFACE AND SUBSTANTIALLY UNIFORMLY SPACED THEREALONG AND EXTENDING RADIALLY BELOW SAID WELL SURFACE PROFICING ALTERNATING GROOVES AND RIDGES, THE JUNCTURES OF SAID GROOVES AND RIDGES BEING ROUNDED TO AVOID SHARP EDGE PORTIONS, THE RADIALLY INNER SURFACES OF SAID RIDGES BEING SUBSTANTIALLY FLAT AND IN ALIGNMENT FORMING SAID INNER WALL SURFACE, AND EACH OF THE AXIAL SPACING OF SAID RIDGES AND THE AXIAL EXTEND AND RADIAL DEPTH OF SAID GROOVES ALL BEING SUBSTANTIALLY LESS THEN THE SIZE OF SAID ENTRAINED PLASTIC PARTICLES FOR AVOIDING ENTRAPMENT OF SAID PARTICLES IN SAID GROOVES AND CONTINUOUS ABRADING CONTACT OF SAID PARTICLES WITH SAID INNER WALL SURFACE.