• A double eccentric geometry of the disc rotating center
  • Body seat is designed as a tilted cone geometry
  • Valve seat is floating inside the disc profile, seat will be shaped into an elliptical form at closed position
  • 360° continuous line contact between seat and seal of body and disc. the dimensions change duo to temperature influences leads the seat ring to alternate seating position during the cone geometry.
  • The seat rings both of body and disc are solid and real metal, can't be flushed away as lamellar seat.

The value getting from Fig. 2specifies the Actuator Torque required for closing the valve . Since the valve being a torque seatrd design , the closed position of the valve is mot self-locking,the actuator has to keep the torque valve during the valveat closed position.

The values show in Fig.2 are valid for metal seated valve with a seal qualified to IEC 534-4 class IV. For higer tightness requirement i.e. IEC534-4 Class IVS and V, the torque value has to be multiplied by 1.2.


The value getting from Fig. 3 specifies the Dynamic Torque of the valve during open position.The values are valid for Bi-directional flow and expressed in torque per p-unit i.e. in Nm/bar or in ft-bl/psi.
In general, the dynamic torque of seated butterfly valve is smaller then the closing torqud shown in Fig.3. Only relative large valve size working under a high pressure drop can have dynamic torque valre of significant. It must ne considered that the vslue of the pressure drop shall never ve higher than the product out of XTxP1 resp. FL2 x (P1-Pv).
Where XT : Pressure differential ratio factor
P1 : Inlet pressure.
Pv : Saturated vapor pressure of the liquid at the inlet temperture (kgf/cm2abs)
FL: Liquid pressure recovery factor
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