| 摘要 |
The dislosure relates to fluid flow control devices, particularly for use in connection with valves used in the control of fluids under high pressure. In the new structure, the valve trim includes a novel and advantageous form of flow restrictor, which serves to limit flow velocity and which causes the fluid pressure to be reduced in a sufficient number of discrete stages to minimize noise and cavitation. The new flow restictor comprises an axial stack of annular discs, each provided with a plurality of annular baffle ribs projecting from its opposite end faces. The annular baffle ribs on one side of the disc are slotted along a number of equally spaced radii, and the ribs on the opposite side of a disc are similarly slotted, but along radii offset from the first set of radii. When a series of these discs is assembled in a stack, downwardly facing ribs of one disc fit between upwardly facing ribs of a disc next below, providing a series of annular passages interconnected by radial slots. Each series of slots is offset and located between the next series and the preceding series, so that the fluid flow is continually divided and recombined for velocity reduction. In addition, the effective area of the radial slots is less than the area of the annular pasages, such that the fluid is passed successively through a series of restricted orifices and expansion areas in passing through the valve. While many of the basic, underlying principles of the restrictor are known, the specific construction of the restrictor element has important advantages over the known prior art, in that a highly desirable form of restrictor assembly is possible with a relatively minimum manufacturing cost.
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