Patent ID: 6964297

Claim:
A header plate for a heat exchanger comprising: a plate having a tube side and a tank side; and a plurality of apertures extending through the plate; each aperture having a longitudinal axis L and a wall of nonuniform diameter at four locations, the diameter at each location being sufficiently large enough to accommodate insertion of a flow tube into the aperture at an insertion angle α to the longitudinal axis L to allow insertion and removal of a flow tube from the heat exchanger without disassembling a frame of the heat exchanger, where α is greater than zero degrees, and including a seal fixedly engaged within the aperture by shoulders formed by differing diameters of the wall; wherein each aperture has a first portion to accept a flow tube, the first portion adjacent the tube side and having a first diameter to accommodate insertion of the flow tube into the first portion and into the aperture at the insertion angle α; a second portion adjacent the first portion and having a second diameter larger than the first diameter of the first portion, wherein the seal is fixedly engaged in the second portion, with the second portion having shoulders for retaining the seal during insertion and removal of the flow tube; a third portion adjacent the second portion with the third portion having a third diameter smaller than the second diameter of the second portion, and the third diameter is larger than the first diameter of the first portion; and; a fourth portion adjacent the third portion, the fourth portion having a diameter larger than the third diameter of the third portion.