Linear movement of valve (poppet). No possibility of jamming.

Swing type movement of valve (flap). Possibility of jamming.

Positive pneumatic pressure acts as good sealing force continuously when the valve reaches the respective positions. The poppet is pressed against the valve seat by pneumatic pressure eliminating possibility of any leakage.

No positive force is applied after the flap reaches its respective positions. The mechanical play in the gearbox results in small opening due to self weight of flap & flue gas back pressure. This can result in leakage in the long run.

Force is applied at center of poppet ensuring equal distribution throughout the sealing edges.

Force is applied at one end of flap. This results in unequal force distribution. The distant edge gets less force.

Made of Stainless steel which can work upto 850 Deg.C continuously.

Made of carbon steel alloy which is not suitable for more than 500 Deg.C.