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