Flexible PTFE seat
Seat Construction
Reinforced PTFE (15% Glass Fiber/12% Carbon/3% Graphite)
seats having a flexable lip provides bubble tight shut off in
both directions. Suits a wide range of applications. Max. working temperature 200
o
C
Flexible rubber seats ( NBR, EPDM, FPM )
Rubber seats are availiable in NBR, EPDM and FPM. Ridgid seats allow a clean flow passage and prevents fluid deposits
within the seat. Ridgid seats allows uni-directional flow ( i.e. shaft inlet ) providing tight shut off under positive pressure
and vacuum applications.
Flexible Metal seat
Most suitable for high consistency fluid having suspended hard particles, for erosive services and for high temperature ser-
vices >200 o C to 600 o C. Die pressed stainless steel seats with build-in flexible property gives Class IV leakage with minimal
torque requirements.
Fire Safe Design
Flow from Seat Retainer Side:
The lip shaped PTFE Seat moves axially in the direction of flow with the assistance of line
pressure. The tightness between seat and disc increases with increasing line pressure.
Flow from Shaft Side:
With the line pressure acting on the disc, it tries to move towards the seat which is supported by
Seat Retainer. Seat does not move giving leak tight seal.
In case of a fire the PTFE will melt. The metal part of the Fire Safe seat remains intact making the valve construction Fire
Safe.
Note: seats can be changed from one selection to another of the above mentioned. In this case the Seat Retainer ring needs to be changed as well, as every type of
seat ( PTFE, Rubber, Metal, Fire Safe ) comes with it different Seat Retainer construction. On the drawings the blue part is the Seat Retainer ring.
The Double Eccentric disc construction minimizes the interference between seat and disc allowing longer seat life even under
frequent valve operation. Seats are available in various executions, both ridget and flexible, in order to meet specific customer
requirements.
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B-2530-UK-06-2013-REV. A
An
Company
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