| 摘要 |
A particle control screen assembly for a perforated pipe (22) used in a well, a sand filter system, and methods of making same are provided. The screen assembly (21) includes a woven mesh filter media (27) disposed about the perforated pipe (22), and a protective wrapper (28) disposed about the filter media (27). The protective wrapper (28) comprises an outer perforated layer (30) and an inner layer (29, 43) that is disposed between the outer layer (30) and the filter media (27). A surface (36) of the inner layer (29, 43) that faces the outer perforated layer (30) has a non-smooth contour (38), with this surface (36) of the inner layer (29, 43) having portions in direct contact with an inner surface of the outer layer (30). The inner layer (29, 43) is provided with apertures that are disposed in such a way that fluid cannot flow from the outer surface of the outer perforated layer (30) directly radially both through holes (35) of the outer layer and through the apertures of the inner layer (29, 43).
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