| 摘要 |
A drop tube/adapter unit, mounted on the riser pipe of a fuel storage tank, defines a fuel inlet path and an annular vapor return path during a loading operation. A vapor valve, provided in the vapor return path, prevents escape of vapors when a loading operation is not taking place. The drop tube is mounted for universally pivotal movement relative to a vapor valve member thereon, so that the vapor valve will reliably close, if the riser tube is out of plumb. A spring urges the drop tube, valve member to a closed position through a spring support. A stop means engages the spring support and precompress this spring, with the spring support positioned to facilitate its attachment to the adapter. The spring support is attached to the adapter by a threaded connection, comprising a threaded portion at the lower end of the adapter. This threaded portion is interrupted by a recess which positions a ring for sealing the adapter to the upper end of the riser pipe, when the adapter is threaded onto the riser pipe. A fixed angular relation between the adapter and the drop tube is achieved through the use of a locator ring to obtain a desired disposition of an drop tube overfill valve.
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