Method and device for removing the gases from underground spaces, in particular of ducts and wells for cables

摘要

333,606. Siemens - Schuckertwerke Akt.-Ges., (Assignees of Gerlach, F.). Jan. 16, 1929, [Convention date]. Ventilating tunnels; forced ventilation.- Underground conduit systems to which access is obtained through manholes, e.g. those containing electric cables or heating pipes, are ventilated before opening by a portable suction pump connected by a flexible, pipe i to a hood g of impermeable material provided with a sealing ring h and adapted to be pressed over the usual ventilating grid d in the manhole, cover c. The Specification as open to inspection under Sect. 91 (3) (a) refers to Specification 333,604. This reference does not occur in the Specification as accepted.