| 摘要 |
An apparatus for freeing a seized valve having an elongate valve actuating stem (10) projecting out of the valve comprises means for repeatedly applying an impact force to the valve actuating stem along its longitudinal axis. The impact force may be applied alternately in opposite directions along the longitudinal axis and the apparatus may comprise gripping means for gripping and engaging with a projecting portion of the valve actuating stem. The repeated application of the impact force to the valve actuating stem along its longitudinal axis induces vibration and causes movement of those portions of the valve causing seizure. This helps to dislodge scale and other deposits and enables the valve to be moved.
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