| 摘要 |
An improved dump valve assembly (22) is provided for use as a part of an elongated, sectionalized, tubular downhole pipe string (18). The assembly (22) includes a tubular pipe section (24) having endmost threading (34, 38) and a rupture disc fitting (26); the fitting (26) includes a metallic, preferably concavo-convex disc (50) with performed lines of weakness (52, 54) on one face thereof. The section (24) is interconnected between a pair of lower pipe sections (20a, 20b). In operation when it is desired to elevate the string (18) from the well, the fluid within the string (18) is pressurized sufficiently to rupture the disc (50), thereby allowing fluid within the string (18) to drain. The string (18) and other well components can then be removed from the well without contamination owing to spillage from the tubular string (18).
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