Rotary sprinkler riser extension kit

A riser extension kit configured for installation on a rotary sprinkler that is operational without such kit installed, the rotary sprinkler having a an enclosure having (i) an outlet end and an inlet end, (ii) a rotatable stem installed within the enclosure and having a geared end, and (iii) a cap having means for removable attachment to the outlet end of the enclosure, the stem configured to direct fluid entering the inlet end to flow through the stem and the cap and to exit the outlet end, the riser extension kit comprising:

• an external riser extension attachable between the cap and the outlet end of the enclosure, the external riser extension defining a channel configured to allow passage of the stem through the external riser extension;
• and
• an internal riser extension having a lower end configured to arrest rotation of the rotary sprinkler and an upper end configured to engage the geared end of the stem, a baffle formed at an intermediate position between the lower end and the upper end, a plug extending from the baffle toward the lower end, and at least one through-hole defined through the plug, the at least one through-hole fluidically connecting the inlet end to an interior flow channel extending through the stem.