Patents Assigned to Hitachi Engineering Co., Ltd.
  • Patent number: 4434620
    Abstract: A condensation system for use in a power plant including a steam generator and steam turbine comprises at least one side stream condenser. The side stream condenser defines therein first and second hot wells with the first hot well receiving therein condensate produced by condensing steam exhausted from the steam turbine. A condensate pump device forcibly delivers the condensate through a condensate feed line having one end thereof connected to the first hot well and the other end communicating with the second hot well. A first purification device is provided in the condensate feed line to remove impurities from the condensate flowing therethrough. A main condensate pump device forcibly delivers the condensate through a main condensate feed line having one end thereof communicating with the condensate feed line and the other end connected to the steam generator.
    Type: Grant
    Filed: June 29, 1982
    Date of Patent: March 6, 1984
    Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.
    Inventors: Hitoshi Ishimaru, Yoji Nagai, Toyohiko Masuda
  • Patent number: 4383448
    Abstract: A semi-automatic scanner for ultrasonic flaw detection comprises a carriage travelling on a guide rail, a guide arm extending in a direction transverse to the travel direction of the carriage and supported by the carriage so as to pivot in a plane transverse to the travel direction of the carriage, a probe holder slidably supported by the arm, and a probe mounted on said probe holder so as to pivot about two axes transverse to each other. One of the axes is generally in parallel to the travel direction of the carriage. The carriage is driven by a motor, and the probe is moved by manual or motor-driving operation in a direction transverse to the travel direction of the carriage while pressing the probe on a surface to be inspected, whereby the probe accurately follows the surface even if the surface is curved.
    Type: Grant
    Filed: September 5, 1980
    Date of Patent: May 17, 1983
    Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.
    Inventors: Hirotsugu Fujimoto, Tsutomu Hayashi, Tatsukuma Hosono
  • Patent number: 4365476
    Abstract: Condensation system for use in a power plant. The condensate system includes side stream condenser defining therein first and second hot wells. Condensate is delivered from the first to second hot well through a condensate feed line. Condensate is introduced from the condensate feed line into a tank through a first spill-over line. Condensate is supplied from the second hot well to the power plant through a main condensate feed line. Condensate is introduced from the main condensate feed line into the tank through a second spill-over line. Actuator is operative in response to signal from a level detector detecting level of condensate in the first hot well, to regulate opening degree of a supplementary feed valve in the supplementary feed line, to close one of first and second spill-over valves in the first and second spill-over lines, respectively, and to open the other spill-over valve.
    Type: Grant
    Filed: October 22, 1980
    Date of Patent: December 28, 1982
    Assignees: Hitachi Ltd., Hitachi Engineering Co. Ltd.
    Inventors: Toyohiko Masuda, Takeshi Ueno, Yoji Nagai, Hitoshi Ishimaru, Shozo Nakamura
  • Patent number: 4326159
    Abstract: Voltage, current and field voltage of a generator connected to an electric power system are sampled at a predetermined period for analog-digital conversion and then led to a digital computer. In addition to computation for AVR, the computer computes from its input the generator output power, and also monitors the occurrence of a fault, the removal of the fault and variation in the generator output in the system. After the occurrence of a fault, the field excitation of the generator is intensified until the generator output power reaches substantially a peak value, but after the peak value is substantially passed by, the excitation is conversely depressed to a value below the level which is present before the fault occurs. When the generator output power recovers the value which is present before the fault occurs, the computer returns to deliver the AVR output.
    Type: Grant
    Filed: August 30, 1979
    Date of Patent: April 20, 1982
    Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.
    Inventors: Hiroaki Aotsu, Akira Isono, Tsutomu Inayama, Mamoru Fukushima
  • Patent number: 4245182
    Abstract: A field control apparatus for a generator having a field winding comprises a terminal voltage control unit for controlling a field current of the generator in accordance with a difference between a terminal voltage signal of the generator and a reference voltage signal, which control unit has at least one of a line drop compensation function, an under-excitation limitation function, an over-excitation limitation function, a power factor regulation function, an armature winding over-current compensation function and a cross-current compensation function. The field control apparatus includes a detector as a common signal source for detecting active power and reactive power components at an output terminal of the generator and means responsive to the output of the detector for performing scalar operation in accordance with a function of the added compensation/control function described above.
    Type: Grant
    Filed: March 28, 1978
    Date of Patent: January 13, 1981
    Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.
    Inventors: Hiroaki Aotsu, Akira Isono, Masuo Goto, Koichi Kimura, Yasushi Momochi, Takaaki Kai, Satoshi Kitamura, Akihisa Kaihara, Hirosi Okada