Replacement of Throttling Valve Components for Drilling Rigs:
Replacing the Valve Disc and Valve Seat: Relieve the pressure within the valve cavity, remove the valve cover bolts, and withdraw the valve disc together with the upper section of the valve cover assembly. Remove the slotted round nut, switch pin, hex screws, and the front and rear stop caps; the cylindrical valve disc can then be replaced, and the valve seat replaced simultaneously. Clean the valve cavity, paying particular attention to the sealing surfaces. When installing the new valve disc and valve seat, the clearance between the valve disc and the boss section of the valve cover must be packed with sealing grease; additionally, the interior of the upper cover should be filled with calcium-based lubricating grease to lubricate the bearings.
Replacing the Lip Seals (Packing): First, relieve the pressure within the valve cavity; then, disassemble the protective cover, round nut, handwheel, bearing gland, bearings, and packing gland before replacing the lip seals.
Replacing the Bearings: Disassemble the protective cover, round nut, handwheel, and bearing gland; the bearing can then be replaced. If the lower bearing requires replacement, the valve stem nut must be removed. The bearing clearance is adjusted via the bearing cover; once the adjustment is complete, rotating the handwheel should result in smooth movement without any binding or jamming.