API 609 Metal Seated Butterfly Valve , Industrial Triple Offset Butterfly Valve

Api 609 Metal Seated Butterfly Valve Cast Steel Triple Offset Industrial Valves

1. Standards

Design and Manufacture； API 609. MSS SP-67, MSS SP-68
Inspection and Test: API S98

End flange dimension: ASME B16 5 (NPS≤24). ASME B16 47 B series
BW end dimension: ASME B16.25

Face to face and end to end； API 609

Pressure-temperature ratings: ASMF B16.34

2. The Seal Principle of Hard Seal Butterfly Valve Triple Offset

The Triple Offset Butterfly Valve provides a bi-directional bubble tight shut-off.This geometry ensures that the disc seal contacts the body seat only at the final shut-off position without rubbing or galling, providing a torque generated resilient seal with sufficient “wedging” to ensure auniform seal contact.

3. The Triple Offset Geometry
OFFSET 1 The shaft is offset behind the seat axis to allow complete sealing contact around the entire seat

OFFSET2 The shaft centerline is offset from the pipe and valve which provides interference free opening and closing of the valve

0FFSET3 The seat cone axis is offset from the shaft centerline to eliminate friction during closing and opening and to achieve uniform compressive sealing around the entire seat.

4. Friction Free Sealing for Long Cycle Life
(1) Seat is Cr13 Metal alloy or hardfaced with Stellite as standard.

(2) The gasket is spiral wound SS/Graphite for zero leakage.

(3) Seat ring forces are generated by the torque during closing uniformly around the entire circumference. The resilient seal fleses and energizes, assuming the shape of the seat. The compression forces equally distributed around the perimeter provide a tight bi-directional shut off.
The resiliency of the seal allows the valve body and disc to contract or expand, without the risk of jamming due to temperature fluctuations. It is self-adjusting.

5.Application

Hard Seal (Metal Seated)Butterfly Valve triple offset series are used in such fields as metallurgy, light industry, electric power, petrochemistry, coal gas channel etc.

6. Materials List (Triple Offset Butterfly Valve)