Integral Plastic Ball Valve For Fluid Transmission And Manufacturing Process

A method for the manufacture, by injection molding, of an integral ball valve, the ball valve primarily consisting of polyformaldehyde, polypropylene, and polyethylene materials, the method comprising the following sequential steps;

• (a) providing a spherical enclosure comprising a polypropylene cylindrical structure and further having a collar with a circular through-aperture, a circular inner face, a peripheral surface, and a barrel opening having a ring-shaped outer face, said outer face being oriented parallel to the axis of the circular aperture;
• (b) providing identical left and right leakage seal rings, each seal ring having a first side with dimensions corresponding to the inner face of said spherical enclosure and a circumferential lip on the second side of each ring;
• (c) placing the first side of said left leakage seal ring into the spherical enclosure so as to abut the inner face;
• (d) providing a rod-shaped valve stem having a notch on the first end of the valve stem and a polygonal cross-section comprising the second end of the valve stem;
• (e) providing a valve handle having an internal cavity corresponding to the notch of the valve stem;
• (f) providing a valve ball comprising a polypropylene sphere with outer diameter corresponding to the barrel opening of the spherical enclosure, a through-hole of diameter corresponding to the inner diameter of said leakage seal rings, said through-hole forming a left ball outlet and a right ball outlet;
• and a polygonal socket oriented orthogonal to the through-hole;
• (g) placing said valve ball into the spherical enclosure such that the through-hole is co-axial with the outer face of the barrel opening and such that the polygonal socket of said valve ball is oriented co-axially with the central aperture;
• (h) placing the valve stem downward through the central aperture such that the valve stem shaft is fitted into the valve ball socket;
• (i) providing an annular-shaped spherical enclosure cap comprising polypropylene, with inner diameter equivalent to the ball outlets of said valve ball, a circumferential flange about the circumference of the first side of the spherical enclosure cap, an annular-shaped cap first face on the first side of the spherical enclosure and oriented about the outer perimeter of the circumferential flange, an annular-shaped cap second face oriented about the inner perimeter of the circumferential flange and having an inner diameter corresponding to the right ball outlet;
• said cap first face corresponding to the outer face of said barrel opening;
• (j) placing the first side of said right leakage seal ring in abutment to the second face of said spherical enclosure cap and placing the sealing gasket around the outer diameter of the flange of the spherical enclosure cap;
• (k) placing the cap first face flush against the outer face of the spherical enclosure such that the flange of the spherical enclosure cap fits within the barrel opening of the spherical enclosure;
• (l) co-axially placing a left mold rod and a right mold rod into the left ball outlet and the right ball outlet, respectively;
• (m) providing an injection mold having a first mold cavity and a second mold cavity, each cavity 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 valve body housing encompassing said valve core, and further a left flow pipe and a right flow pipe;
• (n) placing the valve core and mold rods into the first injection mold cavity, placing and securing the second mold cavity onto the first mold cavity, placing the combined mold cavities in connection with a mold injection machine and initiating the flow of molten substance into the combined mold cavities;
• (o) alter cooling of the mold, removing an assembly comprising the integral valve body housing and the left and right outlet/inlet pipes;
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• (p) fastening the valve handle onto the valve stem of the valve core.

An improved method of manufacturing an integral plastic ball valve of the type having a spherical ball with a cylindrical through-hole, a left ball outlet, a right ball outlet, and a polygonal socket in the outer surface of said ball, the improvement comprising:

• (a) assembling a valve core consisting of a spherical enclosure, left and right leakage seal rings, a sealing gasket, the valve ball, a valve stem, and a spherical enclosure cap;
• (b) co-axially placing a left mold rod and a right mold rod into the left ball outlet and the right ball outlet, respectively;
• (c) providing an injection mold having a first mold cavity and a second mold cavity, each cavity comprising a concave profile corresponding to the shape of the valve core and mold rods, thereby forming a valve body housing encompassing said valve core;
• (d) placing the valve core and mold rods into the combined mold cavities in correspondence with a mold injection machine and initiating the pressurized flow of molten substance into the combined mold cavities;
• and
• (e) allowing an adequate cooling time for the mold, and afterwards, removing the integral valve body housing and the left and right outlet/inlet pipes.

A method for the manufacture, by injection molding, of an integral ball valve, the ball valve materials primarily consisting of polyformaldehyde, polypropylene, and polyethylene, the method comprising the following sequential steps:

• (a) providing a spherical enclosure comprising a polypropylene cylindrical structure having a barrel opening manifesting a circular outer face, and a collar with a circular through-aperture,
• (b) providing an annular-shaped spherical enclosure cap comprising polypropylene, further having a circular flange of an outer circumference corresponding to the outer surface of the barrel opening, whereby the spherical enclosure cap fits onto the outer face of the barrel opening;
• (c) providing a valve ball comprising a polypropylene sphere with outer diameter corresponding to the barrel opening of the spherical enclosure, a through-hole forming co-axial left ball outlet and a right ball outlet;
• and a polygonal socket oriented orthogonally to the axis of the through-hole;
• (d) providing identical left and right leakage seal rings, each seal ring having an annular first side and a second side with a circumferential lip, whereby each circumferential lip corresponds to the outer surface of the valve ball;
• (e) providing a rod-shaped valve stem having a notch on the first end of the valve stem and a polygonal cross-section equivalent to that of the ball socket comprising the second end;
• (f) providing a valve handle having an internal cavity corresponding to the notch of the valve stem;
• (g) forming a valve core by means of placing the valve stem downward through the collar of the spherical enclosure so as to fit into the valve ball socket, placing a circular gasket in abutment with the cap first face, placing the assembled valve ball and leakage seal rings into the barrel opening of the spherical enclosure, whereupon placement of the spherical enclosure cap is made onto the outer face of the spherical enclosure, and co-axially placing a left mold rod and a right mold rod into the left ball outlet and the right ball outlet, respectively;
• (h) providing an injection mold for sealed accommodation of the valve core and left and right mold rods and initiating, the flow of molten polyethylene into the combined mold cavities;
• (i) upon cooling of the mold, removing of the end product comprises an integral valve body housing containing the valve core;
• and
• (j) fastening the valve handle onto the valve stem of the valve core.