Strainer Pipe stops pipeline waste such as scale, rust, jointing compound, and weld metal to safeguard machinery and procedures. A strainer is a device that uses a perforated or mesh-straining element to mechanically remove particulates from a flowing fluid or gas in a pipeline. Strainer Pipe is anything used to strain a liquid, such as a pipe fitting through which liquid is passed for purification, filtering, or separation from solid matter.