| 摘要 |
A threaded coupling that has a pair of threaded ends. A number of rigid centralizer ribs are attached or formed on the coupler. Because the coupler has a small length, a special wrench-adapter is used to attach the coupler to the casing string. This adapter fits around the coupler and allows an ordinary wrench to hold the coupler while the casing string is being made up. The coupling also has a gas seal to contain natural gas within the casing without allowing leakage and a torque limiter to ensure that the coupler does not destroy the casing when the casing is rotated in the earth.
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