APPAREIL AUTOMATIQUE POUR LE REGLAGE DE LA PRESSION HYDRAULIQUE S'EXERCANT SUR L'EXTREMITE DE TAILLE D'UN TUNNEL DANS UNE MACHINE A CREUSER DES TUNNELS DU TYPE A BOUCLIER

摘要

An apparatus for automatically controlling tunnel face hydraulic pressure in a hydraulic chamber defined by a rotary cutter head and bulkhead in a shield type excavator used in hydraulic tunnel boring system including a pipe for feeding a hydraulic material with a feeding pump from a reservoir to the chamber and a pipe for discharging a mixture of the fed hydraulic material with ground formations excavated by the cutter head from the chamber to the reservoir with a discharging pump. The apparatus substantially comprises a pressure gauge for measuring actual hydraulic pressure in the chamber, a pressure regulating valve in the feeding pipe as disposed close to the chamber, a first pressure regulator in which a predetermined feeding pressure is preset for comparing the actual pressure measured by the gauge with the predetermined feeding pressure and controllably operating the valve responsive to any difference between the pressures compared in the first regulator, and a second pressure regulator in which a predetermined pumping pressure is preset for comparing the actual pressure with the predetermined pumping pressure and controlling pumping rate of the feeding pump responsive to any difference between the pressures compared in the second regulator. The predetermined pumping pressure preset in the second regulator is preferrably made slightly higher than the predetermined feeding pressure preset in the first regulator.