The upper portion of {HEAD ~ housing} 4 contains {TAIL ~ the aforementioned impeller} 6 immersed in a viscous fluid 18, the fluid completely fills the upper portion of housing 4 
The upper portion of { HEAD ~ housing } 4 contains { TAIL ~ the aforementioned impeller } 6 immersed in a viscous fluid 18 , the fluid completely fills the upper portion of housing 4
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH