TECHNICAL INFO

ECCENTRIC PLUG VALVE
Specifications

Eccentirc Plug Valves shall be of the tight closing, resilient faced, non-lubricating variety and shall be of eccentric design such that the valves pressure member (plug) rises off the body seat contact area immediately upon shaft rotation during the opening movement. Valves shall be drop-tight at the rated pressure (175 psi through 12", 150 psi 14" and above) and shall be satisfactory for applications involving throttling service as well as frequent or infrequent on-off service. The valve closing member should rotate approximately 90 degrees from the full-open to full-close position and vice-versa.

The valve body shall be constructed of cast iron (semi-steel) conforming to ASTM A126, Class B. Body ends shall be:

Eccentric Plug Valves shall have a rectangular shaped port. Port areas for 3" - 20" valves shall be a minimum 80% of full pipe area.

Valve seat surface shall be welded-in overlay, cylindrically shaped of not less that 90% pure nickel. Seat area shall be raised, with raised areas completely covered with weld to insure proper seal contact. The machined seat area shall be a minimum of .125 thick and .500" wide.

The valve plug shall be constructed of cast iron (semi-steel) conforming to ASTM - A126, Class B. The plug shall have cylindrical seating surface that is offset from the center of the plug shafts. The plug shafts shall be integral. The entire plug shall be 100% encapsulated with Buna-N rubber in all valve sizes. The rubber compound shall be approximately  70 (Shore A) durometer hardness. The rubber to metal bond must withstand 75 lbs. pull under test procedure ASTM D - 429 - 73 Method B.

Shaft bearings, upper and lower, shall be sleeve type metal bearings, sintered, oil impregnated and permanently lubricated type 316 stainless stell conforming to ASTM A743 Grade CF-8M. Thrust bearings shall be Nylatron.

Plug valve shaft seals shall be on the multiple V-ring type (Chevron) and shall be adjustable. All packing shall be replaceable without removing the bonnet or actuator and while the valve is in service. Shaft seals shall be made of Buna-N.

Each valve shall be given a test against the seat at the full rated working pressure and a hydrostatic shell test at twice the rated working pressure. Certified copies of individual tests shall be submitted when requested. Certified copies of proof-of-design tests shall be submitted upon request.

Manual valves shall have lever or worm gear type actuators with handwheels, 2" square nuts, or chainwheels attached. Lever actuators shall be furnished on valves 8" and smaller where the maximum unseating pressure is 25 psig or less. Worm gear type actuators shall be furnished on all 4" or larger valves where the maximum unseating pressure is 25 psig or more.

All eccentric plug valves shall be Clow F5412 (Flanged), F5413 (mechanical joint), or F5414 (grooved) or approved equal.