PVC ball valves are installed in water supply lines for household water lines and sometimes in the gardening water system. The valve has an inlet in each end for the supply pipe to enter and depending on the valve can be cemented to the pipe and tightened in place with nuts.
The ball itself has a hole itself drilled from through the center which when aligned with the supply pipe allows water to rush through the hole and serve the attached appliances.
Loosening the valve is a quick process but sometimes replacements are also necessary. Silicone lubricant can be used to lubricate the sticky PVC valves.
The PCV valve is usually located at one end of one valve cover of a V engine or one end of the valve cover in an inline engine.
Injection molding followed by assembly of the parts. In the case of ball valves the plastic may be insert molded around a ball made of a material that is not melted or wetted by the PVC during molding and has sufficiently low coefficient of friction mated with PVC.
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