| 摘要 |
A subsurface pit for servicing aircraft on the ground and having walls with an opening into which a refueling conduit extends is provided with both a ground moisture seal and a pressure seal located about the moisture seal. Together the ground moisture seal and the pressure seal define a fluid tight cavity therebetween which is pressurized with air to approximately three pounds per square inch above atmospheric pressure. A pressure gauge is coupled to the pressure seal by means of a disconnectable fitting to allow pressure within the cavity between the seals to be externally monitored.
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