Flowserve TX2 Triple Offset High Performance Butterfly Valve IOM - Manual (Page 3)

Flow Control Division
3
SECTION I
THEORY OF OPERATION
The valve design is based on a double eccentric geometry of the disc rotating center, utilizing a floating
radius machined seal ring, in conjunction with an inclined cone seating surface of body. This design
makes the disc cam back and away from body seat, eliminating wear between the seat and seal ring. It
also compensates for deviations of the geometry caused by temperature or tolerance changes. (Fig. 1)
The disc seal of valve deflects from its regularly circular shape to an elliptic form when it reaches the
closed position. This matches the inclined cone of body seat geometry, creating the sealing between disc
seal and body seat. Dimension changes due to temperature fluctuations cause the seal ring to adjust its
seating position within the inclined cone geometry, thus maintaining a positive seal as usual.
Due to the unique conical surface of the valve, there is a “preferred” and “non-preferred” flow direction.
The preferred flow direction would be with the shaft upstream and the direction is marked on the body
with a directional arrow. The shaft side is referred to as the high pressure side of the valve.
SECTION II
PRELIMINARY PRECAUTIONS
FOR SAFETY, FOLLOW THESE CAUTIONS BEFORE INSTALLING, REMOVING OR
DISASSEMBLING YOUR VALVE.
1. MUST KNOW WHAT MEDIA IS IN THE PIPELINE.
2. MAKE SURE THE LINE IS DEPRESSURIZED.
3. USE PROTECTIVE CLOTHING AND EQUIPMENT TO AVOID INJURY. KEEP HANDS AND
OTHER BODY PARTS OUT OF THE VALVE.
4. ALWAYS ENSURE THE VALVE IS IN THE FULLY CLOSED POSITION BEFORE
INSTALLATION, REMOVAL OR DISASSEMBLY.
5. ENSURE THAT FLANGE FACES ARE CLEAN BEFORE INSTALLATION IN PIPELINE.
Preferred
direction of flow