shifted slidable sleeve 51 within the crossover assembly 40 as shown in this open position in fig2 crossover ports 45 provide a fluid flow path 47 in communication with the fluid flow passage 44 and laminar fluid flow area 46 is thus provided the return flow paths 43 through the crossover assembly 40 retain their integrity accordingly the enlargements of the crossover ports 45 defining the fluid flow area of 46 will be considerably larger than the fluid flow area of 42 at the point of the change of direction of the fluid flow passing downwardly within the crossover means 40 and into the exterior of the liner assembly 20 the enlargements of the crossover ports 45 should be at least about three times larger than the flow area 42 and preferably about five times larger thus at such point turbulent fluid flow within the fluid flow passage 44 has been converted to laminar fluid flow through the crossover ports 45 thus greatly abating the tendency of such fluid to abrasively erode or otherwise deleteriously effect the integrity between the return flow path 44 within the crossover assembly 40 and the crossover ports 45 from within the interior of the crossover assembly to the exterior of the liner 20 now with respect to the views illustrated in fig5 8 the apparatus 1 of the present invention is shown in the squeezing position fig5 with the valve head 54 upon its valve seat and shifted into lower position to prevent fluid flow from the top of the well downwardly within.