| 摘要 |
A downhole plunger for a gas/oil well comprises a valve to regulate fluid flow past the plunger and a thermal actuator to control the valve. The thermal actuator of the disclosed device enables the valve to open and close apertures without relying on the physical impact generally required of mechanical valve bypass plungers. In addition, the thermal actuator provides for a brake to reduce a plunger's travel rate as it approaches the bottom or top of a well. The thermal actuator partially opens apertures to slow a plunger down as it approaches the top of a well. Likewise, the thermal actuator partially closes apertures to slow the plunger as it approaches the well bottom. A thermally actuated plunger comprising an expandable outer diameter is disclosed, as is a plunger in combination with a data logger and a thermal activated brake.
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