Abstract: An expansible bellows, includes a pair of end plates attached together and sealed around their peripheries such that their inner faces confront each other to define between them an expansible chamber for containing a fluid. One end plate is formed with an inlet port to the chamber; and the other end plate is formed with an outlet port from the chamber. The inner and outer faces of both end plates are formed with recesses which permit the center portions of the end plates to flex outwardly, and thereby to expand the chamber, when pressurized fluid is inletted into the chamber via the inlet port and blocked from flowing out of the chamber through the outlet port.Also described is a pulsator including such a bellows serving as the expansible chamber of the pulsator.

Abstract: A fluid pulsator includes a housing containing a fluid reservoir, an inlet port, an outlet port, and a valve assembly biassed to an open position by a predetermined biassing force, the valve assembly includes a surface exposed to the inlet pressure to close the valve assembly when subjected to an inlet pressure greater than the biassing force. An inlet control passageway into the reservoir is dimensioned to produce a flow rate smaller than that in an outlet control passageway from the reservoir.

Abstract: A filter operable in either a filtering mode or in a flushing mode, includes a cylindrical filter body, and a plurality of partitions defining a plurality of axially-extending, circumferentially-spaced filter compartments each communicating with an axial section of the filter body. All the filter compartments communicate with the fluid inlet except for at least one filter compartment which is blocked. A flushing pathway is provided between each blocked compartment and the flushing outlet. A valve in the flushing pathway is movable either to (a) a closed position during the normal filtering mode, or (b) an open position during the flushing mode.