tube port distributor exterior radius 144 represents the distance between the vertical axis of the port distributor 20 and the exterior surface 28 of the pour tube in a horizontal plane of the port distributor exit line 146 represents a radial line in the horizontal plane from the vertical axis of the port distributor for certain embodiments of the present invention all exit lines emanating in a horizontal plane from the vertical axis 20 of the port distributor intersect an exit port wall before they reach the exterior surface 28 of the pour tube fig1 is a side elevation perspective view of the inner walls of a flow assembly 180 of a port distributor and five exit ports contained in an embodiment of a flow tube of the present invention a port height 182 is shown for an exit port 14 fig1 shows a sectional view along section line a a of fig3 of a variant of the embodiment of a pour tube of the present invention shown in fig3 six exit ports exit ports 214 having a port width 228 exit ports 314 having a port width 328 fluidly connect port distributor 18 to the outer surface 28 of pour tube 10 each exit port 214 314 in this embodiment has an inner exit port wall 40 and an outer exit port wall 42 partially defining the exit port outer exit port wall 42 has a greater length in the horizontal plane than does inner exit port wall 40.