The nipple 321 is connected to a source of pressurized air, e.g., to {HEAD ~ an air compressor}, which admits {TAIL ~ air}, gas or steam into the channel 14 
The nipple 321 is connected to a source of pressurized air , e.g. , to { HEAD ~ an air compressor } , which admits { TAIL ~ air } , gas or steam into the channel 14
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH