A guide disc with a contour corresponding to {HEAD ~ the impeller} is further arranged between {TAIL ~ impeller} and cover disc 
A guide disc with a contour corresponding to { HEAD ~ the impeller } is further arranged between { TAIL ~ impeller } and cover disc
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH