Is Lined Ball Valve The Same As An Eccentric Ball Valve?
The Lined Ball Valve utilizes an eccentric valve body, eccentric ball, valve seat, and valve stem to automatically center themselves as they rotate. This allows the valve to tighten as it closes, achieving a perfect seal. The ball and seat of the eccentric semi-ball valve are completely separated, eliminating wear on the sealing ring and overcoming the persistent wear between the seat and the sealing surface of traditional spherical valves. This effectively protects the metal surface of the valve seat. Eccentric semi-ball valves are particularly suitable for use in the steel and aluminum industries, as well as for media such as fiber, fine solids, pulp, fly ash, and petroleum gas.
The operating principle of an eccentric semi-ball valve is that it is typically double-eccentric: the center of the sealing surface is offset from the center of the rotating shaft, and the center of the rotating shaft is offset from the flow path center of the valve body. This creates a rotational engagement angle of approximately 3 degrees between the valve core and the seat. This engagement angle converts the actuator torque into a self-locking, wedge-tight sealing pressure. The V-shaped ball valve evolved from the globe valve. It features the same 90-degree rotation and lifting action, but differs in that the plug body is spherical with a circular through-hole or channel running through its axis. The ratio of the spherical surface to the channel opening is such that when the ball is rotated 90 degrees, the entire spherical surface appears at both the inlet and outlet, thereby shutting off the flow. The V-shaped ball valve requires only a 90-degree rotation and minimal torque to achieve a tight shutoff. The completely flat valve body provides a low-resistance, straight-through flow path for the medium, overcoming the persistent wear problem of the traditional ball valve seat and ball sealing surface. Non-metallic elastic material is embedded in the metal seat, effectively protecting the metal surface of the seat. The seat incorporates a scraper mechanism to effectively remove surface scale, deposits, and adhesions, making it suitable for a wide range of applications and adaptable to diverse operating requirements. It also facilitates disassembly and maintenance, saving costs.
Thus, the eccentric semi-ball valve is not the same as the V-shaped ball valve. Although both belong to the trunnion-mounted ball valve family, they have fundamental structural differences and differ in their applications.
