Integral Plastic Ball Valve for Fluid Transmission And Manufacturing Process

A process of injection fusion molding for the manufacture of an integral ball valve composed of plastic or similar substance, utilized in controlling the transmission of fluids through various sizes of pipelines, comprising the following steps:

• (a) providing a spherical enclosure having a generally cylindrical structure and further having a a top surface with a central circular aperture, a circular wall, a bottom surface, a barrel opening, and a ring-shaped vertically oriented outer face;
• (b) providing a left and a right leakage seal ring, each seal ring having a first diameter and a lip extending continuously about the circumference of one side of each leakage seal ring;
• (c) placing the left leakage seal ring into the spherical enclosure so as to abut the inner face;
• (d) providing a valve ball consisting of a sphere of outer diameter corresponding to the barrel opening of said spherical enclosure, a through-hole of diameter corresponding to the first diameter of said leakage seal rings, said through-hole forming a left ball outlet and a right ball outlet, and a topmost polygonal socket;
• (e) placing said valve ball into the spherical enclosure such that the through-hole is co-axial with the circular wall, and such that the socket of said valve ball is oriented vertically upward proximate said central aperture;
• (f) providing a rod-shaped valve stem having a plurality of circumferentially-circumscribed grooves into each groove which is fitted a gasket O-ring, a top-most notch, and a bottommost shaft having a polygonal cross-section corresponding to the cross-sectional dimensions of the socket of the valve ball;
• (g) placing the valve stem downward through the central aperture such that the valve stem shaft is fitted into the valve ball socket;
• (h) providing a spherical enclosure cap having a first inner face of a certain diameter, a second inner face of a smaller diameter than the first inner face, a cap opening corresponding to the right ball outlet of said valve ball, and a circumferential flange;
• (i) fabricating a sub-assembly comprising a right leakage seal ring placed abutting the second face of said spherical enclosure cap and a sealing gasket placed snugly around the outer diameter of the flange of said spherical enclosure cap;
• (j) placing the spherical enclosure cap sub-assembly flush against the outer face of said spherical enclosure such that the flange of the spherical enclosure cap fits snugly within the barrel opening of the spherical enclosure, thereby forming a valve core;
• (k) co-axially placing a left mold rod and a right mold rod into the left ball outlet and the right ball outlet, respectively;
• (l) providing an injection mold having a first section and a second section, each section comprising a concave profile corresponding to the general longitudinal shape of the valve core and the previously inserted left mold rod and right mold rod, thereby forming a housing encompassing said valve core, and further a left flow pipe and a right flow pipe;
• (m) placing the valve core and mold rods into the first injection mold half, placing and securing the second mold half onto the first mold half, placing the combined mold in connection with an mold injection machine and initiating the flow of molten substance into the mold;
• (n) allowing an adequate cooling time for the mold, and afterwards, removing an assembly comprising the integral valve housing and the left and right outlet/inlet pipes;
• and
• (o) assembling the valve handle onto the valve stem of said valve core, thereby completing said ball valve.