Abstract: A backwash strainer including a body, a strainer element having an inlet side contained in the body, and a space defined between the body and the strainer element. The body includes an inlet to the strainer element and an outlet from the annular space. A nozzle for directing cleaning fluid against the inlet side of the strainer element for dislodging particulate matter from the inlet side of the strainer element mounts to the body. A backwash arm for collecting the cleaning fluid and dislodging particulate matter mounts to the body. The backwash arm is positioned adjacent to and is in close proximity to the inlet side of the strainer element and the nozzle. The backwash arm has an axially extending slot defined by two spaced members having ends positioned adjacent to the nozzle. The backwash arm and the nozzle together may be moveable about a central axis relative to the strainer element.

Abstract: The mechanical strainer unit is connected to a flanged conduit which originates in and extends out of a suppression chamber in a nuclear reactor. The strainer includes a plurality of centrally apertured plates positioned along a common central axis and in parallel and spaced relationship. The plates have a plurality of bores radially spaced about the central axis. Spacer means such as washers are positioned between adjacent plates to maintain the plates is spaced relationship and form communicating passages of a predetermined size to the central apertures. Connecting means such as bolts or studs extend through the aligned bores to maintain the unit in assembled relationship and secure the unit to the pipe. By employing perforated plates and blocking off certain of the communicating passages, a dual straining effect can be achieved.