Abstract: Debris adhering to the outer surface of a barrel-type fish screen is cleared by air bursts from a series of perforated air pipes positioned inside the outer foraminous shell of the screen, the perforations being holes with axes at an acute angle to the screen radius for efficient use of the air. Separately, the conical water collection manifold mounted inside the shell is open at its narrow end, with a valve mounted to that open end to control the opening. The opening prevents reduced water inflow at that end of the manifold, and the valve adjusts the access of the surrounding water to the opening, thereby allowing the manifold to be tuned to more closely approach a uniform distribution of axial water flow along the length of the collection manifold for different ambient conditions.

Abstract: A barrel type fish and/or particulate screen includes mesh stretched over a supporting cylindrical shell having closed ends. The closed interior opens to a fluid withdrawal conduit, which is connected to an outlet. An inner, substantially conical withdrawal manifold is provided with the base of the substantially conical withdrawal manifold connected to the withdrawal conduit and the manifold extending substantially the axial length of the cylindrical mesh. The substantially conical withdrawal manifold defines uniformly sized and arrayed flow apertures. These flow apertures have the same unit area per unit length of the substantially conical withdrawal conduit. This same unit area per unit length produces within the withdrawal manifold, a substantially constant velocity at all cross-sections of the manifold taken normal the flow along the major axis of the substantially conical shape. Flow velocity distribution through the metal mesh is maintained uniform at all rates of flow through the device.