| 摘要 |
A mechanical tubing drain connected in a tubing string in an oil well. The invention, which provides means for selectively opening and closing drain ports to drain fluid from a tubing string, comprises a ported mandrel slidably encased in a correspondingly ported sleeve. Seal means are provided about the mandrel port. Means are also provided to maintain proper longitudinal alignment between the mandrel and sleeve ports as well as guiding and restricting the movement of the sleeve about the mandrel. Spring loaded shoes attached to the sleeve engage the well casing to hold the sleeve immobile relative to the ported mandrel. In operation, the mandrel is rotated to selectively align the mandrel and sleeve ports to permit unloading of the tubing contents.
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