42 of trapezoidal cross section between a position intermediate the ends of the valve poppet as shown in fig2 and the lower end thereof the groove 42 defines a helical thread or land 44 on the valve poppet also of trapezoidal cross section adapted to interfit with turns of the thread or land 30 formed on the inside bore surface 28 of the surrounding trim cage 24 the poppet is formed of hard wear and temperature resistant ceramic material and the cross section of the land 44 on the poppet valve member is of the same shape as the land 30 on the hollow trim cage the spacing between turns of the respective lands is greater than the base width of the lands in order to provide a helical flow passage 46 defined between the interfitting lands this flow passage communicates between the inlet slot or opening 26 in the trim cage 24 and the lower end of the valve poppet 40 and trim cage to provide a throttling flow passage for the fluid media when the valve poppet is opened as shown in fig1 when the valve poppet 40 is in the closed position the spherical surface 38 at the lower end of the poppet is seated against the frustroconical annular seating surface 36 on the valve seat 32 and in addition the inlet slot 26 in the trim cage 24 is closed off by the adjacent body portion of the valve.