EN 593 Double Eccentric Butterfly Valve | Double Flanged & Gear Operated

Design Features

Metalsin supplies EN 593 double eccentric butterfly valves to waterworks applications, which are gear operated with double flanged ends. These valves feature:

• Double eccentric design: This design is also known as double offset. The first offset is an axial offset of the shaft to the seating contact. The second offset is an offset from the valve body (or pipeline) centerline to the valve disc centerline. The double eccentric design offers significant advantages over concentric types, including reduced friction and wear due to the lift of the disc away from the seat, resulting in a longer lifespan and lower maintenance. They provide a tighter seal, making them ideal for zero-leakage applications, and are designed to handle higher pressures and temperatures. Additionally, this design features enhanced durability, precision in flow regulation, energy-saving operation due to reduced torque, and ease of installation.
• Double flanged: The butterfly valve has double flanged body ends for connection to flanges of adjacent components by individual bolting. The flanged ends shall be cast integrally with the body and shall be in accordance with (1) EN 1092-1, EN 1092-2, EN 1092-3, EN 1092-4 for PN designated butterfly valves; (2) EN 1759-1, EN 1759-3, and EN 1759-4 for class designated butterfly valves.

EN 593 double offset flanged butterfly valve, worm gear operated, pinned double shaft, DN1200 PN10, supplied to Talca, Chile.

• Worm gear operated: When operating a butterfly valve with a manual worm gear, the operator directly rotates the worm gear handwheel by hand. The principle is that the valve stem and the disc are rotated through the worm gear drive. Clockwise rotation usually closes the valve, while counterclockwise rotation opens it. During the operation, the operator should accurately control the rotation angle and speed according to the valve indication and limit device to adjust the fluid flow or shut off the fluid, ensuring that the valve is in the correct open or closed position.
• Pinned Double Shaft: It characterized by by having a stub shaft at each of the upper and lower ends of the valve disc. Each of the stub shaft (also called “half shaft”) is pinned to the disc. The upper stub shaft transmits driving torque to the disc, while the lower stub shaft is used for positioning. The disc can rotate from 0° (fully closed) to 90° (fully open). Due to its low fluid resistance and quick opening and closing, it is especially suitable for large-diameter valves.

Technical Specification

Technical drawing for EN 593 double eccentric butterfly valves, flanged, pinned double shaft, worm gear operation.

Design standard: EN 593; Rubber seat ring is bonded on the edge of the disc; Mounting flange pad according to ISO 5211; Flange dimensions in accordance with EN 1092-1 PN10/PN16; Rated working pressure: 16 bar for DN80 to DN1200, 10 bar for DN1400 to DN2400; Rated working temperature: -4°F ~230°F for EPDM seat, 14°F ~176°F for NBR seat.