Eccentric Valves
Eccentric Valve is a rubber-lined slurry or fluid valve with an eccentric rotary cut-off body to reduce corrosion and wear on mechanical moving valve parts. Eccentric valve is a rubber-lined slurry or fluid valve with an eccentric rotary cut-off body to reduce corrosion and wear on mechanical moving valve parts. An irrigation valve has a valve body with an inlet passage, an outlet passage, and a valve seat intermediate the inlet passage and the outlet passage. A diaphragm includes a valve seat engaging portion that cooperates with the valve seat to control flow through the valve. The valve seat and the valve seat engaging portion of the diaphragm are offset relative to the inlet passage to improve flow through the valve to reduce pressure and energy loss.
An eccentricity tolerant valve stem seal assembly includes an elastomeric seal having an upper metal retainer extending down and within an upper seal portion which has an inwardly directed sealing lip for contacting a valve stem. There are also a flexible middle and a lower seal portions. The lower seal portion is connected to a lower metal seal retainer that is disposed up to a lower edge of the middle seal portion. The flexible middle seal portion allows the upper seal portion to flex from an eccentric valve stem without losing the sealing function of the sealing lip. In cooperation with the above described structure, a separate cover may be in a tight tolerance fit with the lower seal retainer over top of the eccentricity tolerant valve stem seal, in order to limit axial displacement of the upper portion of the seal due to high manifold pressure.
Triple eccentric (offset) Design prevents galling and scratches between the metal seat and the metal disc due to its unique design. The only time where the seal comes into contact with the seat is at the point of complete closure. Triple offset valves are generally used in applications which require bi-directional tight shut-off in oil and gas, LNG/NPG terminal and tanks, chemical factories, and shipbuilding. They are also used for dirty/heavy oil to prevent extrusion.