| 摘要 |
A cementing head is disclosed, which is particularly designed for injecting an omega-type cementing plug into a well casing. Prior to cementing, the plug is retained in a housing. Located above the plug is a movable plunger, actuated by an operating fluid, such as hydraulic fluid. Below the plug is a control valve. When the valve is closed, it prevents any accidental downward movement of the plug into the well casing. Following injection of the cement slurry into the casing, the valve is opened, and the plunger is moved down to push the plug through the valve and beyond the cement inlet. A fluid such as water is passed through the cement inlet, under pressure, to push the plug down the casing behind the cement slurry.
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