In carrying out the above object, a Check Valves according to the invention has a cage including a tubular wall having an upstream end and a downstream end, and with the upstream end of the tubular wall being open to receive fluid flowing downstream through a passage and past an annular seat that diverges from a round edge at which the passage terminates. The cage includes a downstream end that partially closes the downstream end of the tubular wall but includes openings through which the fluid can flow in a downstream direction therethrough. The tubular wall has a generally round shape including radially extending outward and inward undulations such that insertion of the cage into a valve bore downstream from the seat permits fluid flow in a downstream direction externally of as well as through the cage. A valve element of the valve is embodied by a ball received within the tubular wall of the cage and guided by its inward undulations. The ball has a sufficiently large diameter so as to engage the seat at a spaced relationship from the round edge at which the passage terminates.

The manner in which the radially extending outward and inward undulations permit fluid flow in a downstream direction both externally of the cage as well as through the cage permits increased fluid flow, while the guiding of the valve element ball by the inward undulations provides a precise guiding to the closed position with the ball spaced from the round edge where the passage terminates so that there is no edge wear that could cause eventual leakage.

In one preferred construction, the valve also includes a spring that biases the ball toward the seat to close the passage. This spring is disclosed as being round and having a downstream end seated by the downstream end of the cage and an upstream end that seats against the ball. Best results are achieved when the round spring has a cylindrical shape of a helical construction.

The cage of the check valve is disclosed as having different embodiments. In one embodiment, the cage has its tubular wall and downstream end unitary with each other and is preferably made with a drawn construction. Another embodiment of the cage has the tubular wall and downstream end of the cage made with a two-piece construction, preferably with the tubular wall having an extruded construction defining the radially extending outward and inward undulations.

The outward and inward undulations of the tubular wall of the cage are curved with the outward undulations having a greater radius of curvature than the inward undulations. Also, the downstream end of the cage is constructed to include a spider having a central portion and legs projecting from the central portion to the downstream end of the tubular wall to define the openings through which the fluid flows through the cage. The cage has the same number of outward undulations as the number of openings in the downstream end of the cage, and the openings of the downstream end of the cage are in respective alignment with the outward undulations of the tubular wall of the cage.

The Check Valves is disclosed in one practice as being mounted within a component that defines the passage and seat as well as being constructed to provide other functions. Other embodiments also include a valve housing that defines the passage, the valve seat, and the valve bore, and the valve housing includes an external surface that provides mounting of the CHECK VALVES for use such that it provides a self-contained unit.

The objects, features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.

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