Made in Japan
Manufacturer: Nippon Daiya Valve
Model: Ball Valves

Basic structure and sealing principle of ball valves

Fig. 1

Valves in which a ball rotates on a valve stem as a shaft to control the fluid.

As shown in Fig. 1, the flow path has the same shape as the piping, and there are few elements that give resistance to the fluid, so the structure has extremely low pressure loss when fully opened

Fig. 2: Floating ball type

Fig. 3: Fixed ball type

The fixed ball type has a structure in which the upper and lower portion of the ball are supported and fixed by the stem and trunnion as shown in Fig. 3.

With this structure, the fluid is closed using the spring force at the back of the seat and the pressure on the primary side applied to the back of the seat when fully closed.

Therefore, the seal is on the primary side, and it is characterized by less fluctuation of operating torque against fluctuation of flow pressure.

It is mainly used for high pressure (JIS30K, CL600 or higher) and large bore size (DN250 or higher).

Features of ball valves

①Easy operation of fully open and closed