{TAIL ~ A series} of packing nuts 18 are threadably mounted on respective packing studs 20 so as to adjust {HEAD ~ the loading} on the packing within the bonnet and around the valve stem 
{ TAIL ~ A series } of packing nuts 18 are threadably mounted on respective packing studs 20 so as to adjust { HEAD ~ the loading } on the packing within the bonnet and around the valve stem
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH