Method for cleaning contaminated ground using heated medium - uses injection lance with medium heater and vacuum lance, both vertical and perforated with conical ends and helical blades

摘要

The method is for cleaning contaminated ground and in which a heating medium is injected in to the ground by an injection lance. The medium moves around underground and is fed out by a vacuum, i.e. being sucked through another lance. The lances are roughly vertical and the transport of the medium along the lance is blocked. The medium heater is connected to the injection lance (1), and a contaminated medium retainer as well as a vacuum source associated with the vacuum lance which are all suitable to be inserted in the ground. The vacuum lance has a helical blade (15) under a number of inlet holes (12,13) and the medium is prevented from leaking out of the injection lance except from flow holes (6) in its blades (4), both having conical ends (3,4).