| 摘要 |
Mobile tanks, such as the tanks of railway tank cars and the tanks of automotive tank trucks, often have bottom discontinuities susceptible in an accident to impact damage that could permit release of harmful tank contents. Such bottom discontinuities, by way of example, are downwardly projecting parts from bottom outlet valves, washouts, blind flange closures and sumps. This invention contemplates a protective device for such bottom discontinuities, the device comprising a shaped metal plate having a central opening adapted to receive and enclose any bottom discontinuity requiring protection, the plate adapted to be mounted in engagement with the tank, the surface of the plate opposite from the tank tapering toward the tank forwardly and rearwardly from the central opening on skid slopes which terminate in spaced relation with the tank, the plate at the terminations of the slopes being curved toward the tank on convex curves to define a curved undercut periphery free of any corner facing the tank, whereby in consequence of severe impact on the protective device, the bottom discontinuity is protected and the tank deforms around a portion of the curved undercut periphery, the tank deformation being of such shape and magnitude that rupture of the tank is avoided.
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