These valves are closed when {HEAD ~ the separator tube} 16 is inserted into {TAIL ~ the collection tube} 10 as shown in FIG 7, but opened as the separator tube 18 is removed from the collection tube 10 as shown in FIG 7a so as to allow air to enter the collection tube 
is inserted into
These valves are closed when { HEAD ~ the separator tube } 16 is inserted into { TAIL ~ the collection tube } 10 as shown in FIG 7 , but opened as the separator tube 18 is removed from the collection tube 10 as shown in FIG 7a so as to allow air to enter the collection tube
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH