| 摘要 |
<p>A shutdown seal is provided in a pump for activation to prevent passage of fluid along a shaft relative to a fluid-containing housing of the pump through which the shaft extends. The shutdown seal is an annular member having a mounting flange and a sealing collar. The mounting flange is attached to the housing, and the sealing collar is disposed about the shaft. The annular member is constructed of shape memory metal material which below its transition temperature has an expanded configuration in which its annular sealing collar portion is spaced from the shaft so as to define a deactivated unsealed condition of the shutdown seal. On the other hand, above the transition temperature of the material the annular member has a contracted configuration in which its sealing collar contacts the shaft so as to define an activated sealed condition of the shutdown seal. In one embodiment, the annular member of the shutdown seal forms a stationary part of a slip joint secondary seal coupled between the housing and shaft. In another embodiment, the annular member of the shutdown seal forms a hollow shell attached to the interior of a stationary part of a slip joint secondary seal coupled between the housing and shaft.</p> |
