Upper and lower manually operated valves illustrated at 24 and 25, respectively, are illustrated for supplying air through the lines 24a and {HEAD ~ 25a} to {TAIL ~ the air jet devices} 
Upper and lower manually operated valves illustrated at 24 and 25 , respectively , are illustrated for supplying air through the lines 24a and { HEAD ~ 25a } to { TAIL ~ the air jet devices }
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 REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL