摘要 |
A filter has three filter elements, e.g., screens, for trapping particulate material while allowing passage of a fluid. The second sides of each of the first and second screens are connected to an intermediate passage, and the second side of the third screen, and the intermediate passage, are connected to a filter outlet port. The filter has two alternately selectable configurations. In a first configuration, the first side of the first screen is connected to a filter inlet port, and the first side of the second screen is connected to the first side of the third screen. In the second configuration the first side of the second screen is connected to the inlet port, and the first side of the first screen is connected to the first side of the third screen. The first and second screens alternately filter particulates which are subsequently flushed and then trapped by the third screen for periodic removal.
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