a control ring having a wall with an inside and outside surface, said control ring rotatably fitted into said housing cavity, said {HEAD ~ control ring} having {TAIL ~ a vent} in said wall, said vent communicating with said outlet port 
having
a control ring having a wall with an inside and outside surface , said control ring rotatably fitted into said housing cavity , said { HEAD ~ control ring } having { TAIL ~ a vent } in said wall , said vent communicating with said outlet port
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH