| 摘要 |
A vacuum excavation system which incorporates a low consumption air lance, a highly efficient multi-stage vacuum generation system effectively isolated from the waste stream and the air source, and a highly portable material collection system. The air lance includes a cylindrical main body which narrows to a flat taper nozzle at the digging end, and a tee-shaped handle with a swivel type air fitting at one end, while the vacuum generation system is a multi-stage ejector fitted onto a collection drum and consisting of successive venturi tubes with pressure equalizing check valves on the second and higher stages, the material collection system consisting of the drum and hoses or pipes connected to the drum through a separate opening. The system can be powered entirely by one 185 cfm portable air compressor, available from local tool rental firms if one is not owned, so than nearly any contractor, utility company, or design firm can easily outfit themselves for vacuum excavation, at a cost for the excavation system less the air compressor of less than one tenth that of a conventional system.
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