Valve stem---Parts that transmit the opening and closing force to the opening and closing parts
Stem nut---Parts that form a kinematic pair with the valve stem thread
Packing---Filling material placed in the stuffing box (box) to prevent leakage of media along the valve stem. Common packing materials for valves include flexible graphite, polytetrafluoroethylene, etc.
Stuffing box--- a structure filled with packing on the valve cover (or valve body) to prevent the medium from leaking from the valve stem.
Packing gland---Parts used to compress the packing. The packing gland can also be composed of a pressure plate and a gland. The packing gland can compress the packing in the form of gland bolts (gland bolts) or gland eyebolts (eyebolts) and nuts.
