When the member is in its upper position, {TAIL ~ the ring} is in the path of the air stream emitted by the fan to produce {HEAD ~ a stream} of bubbles 
When the member is in its upper position , { TAIL ~ the ring } is in the path of the air stream emitted by the fan to produce { HEAD ~ a stream } of bubbles
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH