A strainer valve is installed into a plumping system in order to purify and filter the flow or separate it from solid matter. Strainer valves block debris from continuing along the system, such as scale and rust and therefore preventing their harmful effects. This in turn reduces the need for plumbing maintenance. Crossling stocks Y-type strainer valves. These can be used in suction or vacuum conditions and can be installed either vertically or horizontally into the system.