The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 17, 1978
Filed:
Feb. 09, 1977
Tekken Construction Co., Ltd., Tokyo, JA;
Abstract
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 first pressure gauge for measuring actual tunnel face hydraulic pressure in the chamber, a feeding-pipe bypass provided close to the chamber, a first pressure regulating valve provided in the bypass, a second pressure regulating valve in the feeding pipe bypassed by the bypass, a first pressure regulator in which a first predetermined feeding pressure is preset for comparing the actual pressure measured by the first gauge with the first predetermined feeding pressure and controlling the second valve responsive to any differences between the both pressures compared in the first regulator, a second pressure gauge for measuring fed-hydraulic-material pressure upstream the bypass a third pressure regulating valve provided in the feeding pipe upstream the second pressure gauge, and a second pressure regulator in which a second predetermined feeding pressure is preset for comparing the measured fed-hydraulic-material pressure with the second predetermined pressure and controlling the third valve responsive to any differences between the both pressures compared in the second regulator. The second predetermined feeding pressure is preferrably made slightly higher than the first predetermined feeding pressure.