Patent ID: 7185677

Claim:
A conduit, comprising: a body having a passage therethrough having an inner diameter; an elongate member in the passage in engagement with the body, the elongate member defining at least a portion of a helix, the elongate member having a length and two side edges, defining a width; a pair of fins extending inward from the elongate member and length-wise along the length of the elongate member, defining an intermediate portion of the elongate member between them, each of the fins having a base that is joined to one of the side edges and a free edge, the free edges defining an inner diameter that is smaller than the inner diameter of the passage to impart a spiral flow pattern onto fluid flowing through the passage, the elongate member having a helix angle such that over one revolution of the helix, a gap will exist between the side edges of the elongate member at the start of the revolution and the end of the revolution by more than the width of the elongate member.