Hitachi, Ltd.

Babcock-hitachi Kabushiki Kaisha

Shigeyoshi Kawano

Nobuo Kurihara

Yoshio Sato

Masayoshi Sunada

Hisao Hanmura

Yukio Fukayama

Hiroshi Matsumoto

Yoshiki Noguchi

Katsukuni Hisano

Hiroshi Kinoshita

Shigehisa Sugita

Kazuo Ikeuchi

Hiroyuki Kaku

Masahiro Ueno

Mitsuyo Nishikawa

Yoshiyuki Nakano

Tadayoshi Saito

Tatsuo Iwasaka

Fumio Kato

Masahide Nomura

Koji Yamauchi

Shigeru Nozawa

Masakatsu Nishimura

Tadashi Kurihara

Katsuyoshi Hori

Yasuhiko Otawara

Toshihiko Higashi

Toshiaki Takuwa

Yasuhiro Tennichi

Toshiharu Myoga

Katsuto Kashiwahara

Masami Joraku

Taro Sakata

Jube Matsumura

Ikuo Kohtaka

Nobuo Satou

Michihiro Iioka

Atsushi Kuramoto

Tetsuyoshi Ishida

Hiromi Kamogawa

Taku Oshima

Hiroshi Jumonji

Koichiro Fukushima

Daizo Iba

Tsuneo Narita

Masahiko Sadakane

Kojiro Yamada

Tomohiko Sadakata

Okikazu Ishiguro

A pressurized fluidized-bed boiler power plant comprises: a pressurized fluidized-bed boiler including a fluidized-bed boiler and a pressure vessel containing the fluidized bed; a single-shaft gas turbine including a gas turbine, an air compressor and an electric generator; and a steam turbine unit in which steam generated by the pressurized fluidized-bed boiler drives a turbine so that electricity is generated. In the power plant, an air cooler is situated on a duct for conveying the compressed air from the compressor to the boiler or at an inlet of the compressor. Alternatively, there may be provided a device for conveying the compressed air from the compressor by way of the air cooler to a space formed by the fluidized-bed boiler and the pressure vessel of the pressurized fluidized-bed boiler. During operation, the compressed air is cooled to a temperature level allowable for the pressure vessel before it is supplied to the boiler.

Pressurized fluidized-bed boiler power plant

A hybrid Rankine cycle system comprises a boiler in which water steam is generated, a steam turbine which is worked by the water steam from the boiler to drive a generator to obtain an electric power, an absorber condenser for introducing thereinto strong absorbent solution to absorb the water steam from the steam turbine to produce weak absorbent solution, and a pump for delivering the weak absorbent solution from the absorber condenser to the boiler. The weak absorbent solution is heated in the boiler to produce the strong absorbent solution to be fed to the absorber condenser and the water steam to be fed to the steam turbine.

Hybrid Rankine cycle system

A boiler/turbine plant controlling apparatus comprises a circuit for driving a turbine inlet steam flow regulator valve on the basis of a difference between a load command signal adjusted by a thermal stress value of a turbine and an actually measured output signal of a plant; a circuit for driving a boiler feed water flow regulator valve on the basis of a difference between a value which is obtained by adding a boiler feed water amount with a super heater feed water amount and a value represented by a boiler input command signal; a circuit for driving a fuel flow regulator valve in accordance with an actually measured fuel amount and a fuel command signal corrected by a difference signal between a primary steam temperature setting signal and a steam temperature signal representative of a primary steam temperature measured value; a circuit for driving a super heater water feed valve on the basis of a difference value between the primary steam temperature setting signal and the steam temperature signal; a circuit for calculating a steam temperature drop through the steam flow regulator valve on the basis of an opening degree of the steam flow regulator valve disposed at an inlet of the turbine and a temperature and pressure of steam at the inlet of said steam flow regulator valve; and a circuit for correcting the steam temperature setting signal on the basis of the calculated value of the calculating means.

Apparatus for controlling boiler/turbine plant

Optimum overall operation of a whole plant including a combustion unit such as a boiler and a wet-process flue gas desulfurization unit comprising an absorption column for removing sulfur dioxide from a flue gas from the combustion unit by absorption using a slurry of an absorbing agent such as limestone powder circulated through absorption column, recycle pumps for circulating the slurry through the absorption column and oxidation air blowers for supplying an oxidation air to the absorption column and a recycle tank is controlled by anticipating a future pH value of the circulating slurry and a future inlet sulfur dioxide content of the flue gas from a present pH value of the circulating slurry and a present inlet sulfur dioxide content of the flue gas and their change rates by computing, anticipating a future desulfurization ratio from both the anticipated pH value and inlet SO.sub.2 content and a recycle rate of the slurry, and controlling the recycle rate of the circulating slurry on the basis of the anticipated desulfurization ratio, where a desired desulfurization ratio can be readily and continuously maintained against any change in fuel species and load of a boiler with reduced utility consumption.

Method for controlling wet-process flue gas desulfurization

Thermal stress of a metal portion of a pressure-tight tube is calculated on the basis of calculated values of a temperature distribution calculator for calculating the distribution of temperature at positions equidistantly arranged in a direction of the thickness of the aforesaid tube on the basis of measured values of metal portion of the aforesaid tube, whereby the thermal stress being changed momently is accurately measured and monitored. Further, there is provided a calculation cycle setter for presetting calculation cycles on the basis of measured values of the fluid temperature in the aforesaid tube. The calculation cycles are made short when fluctuations in the measured values of the fluid temperature are large, while, the calculation cycles are made long when fluctuations in the measured values of the fluid temperature are small.

System for estimating thermal stress of pressure parts

A method and an apparatus for controlling the hot-wire welding process is disclosed in which the heating power for a hot-wire is automatically regulated to a proper value. The wire-heating power after fusing of a filler wire by being overheated is set to a level lower than the heating power immediately before wire fusing, and the wire-heating power is again increased gradually from the set value until the wire is fused by being overheated. By repeating this process, the molten state of the filler wire in the hot-wire TIG welding is automatically kept in optimum condition without requiring any operation of the welding operator or his intuition. Further, during the energization of the filler wire, the instant of fusing by overheating of the wire is detected, and the detected signal is used to sharply reduce or suspend the wire current immediately, whereby spatters which otherwise might be caused by fusing of the overheated wire is prevented or greatly reduced, and the adhesion of the spatters to the arc electrode is prevented, thereby permitting a hot-wire welding operation continuously over a long time. Furthermore, a pulsed current is used for heating the filler wire, and the wire terminal voltage during de-energization of the wire is detected, thereby detecting whether the wire is in contact with a base metal. If the wire is not in contact with the base metal, a current is not supplied during the next pulse application period, so that the current is prevented from flowing from a tungsten electrode to the wire while the wire is not in contact with the base metal.

Method of control and apparatus for hot-wire welding

In a burner igniter using a ceramic heater, the resistance of the ceramic heater is detected to perform feedback control so that the temperature of the heater is maintained substantially constant to prevent both misfiring and overheating, while rapid temperature rise can also be obtained. The resistance value detected by a bridge circuit is fed to a proportional-integral controller which produces a control signal, while the current fed to the ceramic heater is also detected. The control signal and another signal indicative of the current to the ceramic heater are used to control a power source of the ceramic heater so that the current to the ceramic heater is controlled. A monitoring circuit responsive to both the resistance of the ceramic heater and the current fed to the ceramic heater may be added to warn a user that the life of the ceramic heater will soon end. The ceramic heater may comprise a portion having negative temperature coefficient, through which portion leak current would flow when the temperature of the ceramic heater rises so as to prevent overheating.

Burner igniter with a ceramic heater

A system and method for the adaptive control of a process in which a feed forward control signal corresponding to a process demand is calculated according to a predetermined algebraic function, while a feedback correction signal is calculated on the basis of an error of a process feedback signal indicative of an error of a controlled variable from a predetermined setting, and the controlled variable of the process is controlled on the basis of the sum of these two signals. The adaptive control is such that, when a set point of the function deviates from the actual process demand, a value corresponding to the error appears in the feedback correction signal, and this value is used for automatically modifying the function itself to ensure the adaptive control of the process. A determination is made whether or not the process is in the steady state and when steady state operation is determined, the function of the feed forward control signal is modified.

System and method for adaptive control of process

The present invention relates to a method of controlling the operation of large rotary machines such as steam turbines and generators in a thermal power plant or nuclear power plant. More specifically, the invention relates to a method of controlling such operation as increasing or decreasing the speed of the rotary machines or stopping the operation of the rotary machines, by detecting vibration at the time of starting the operation or during the steady-speed operation, by analyzing the detected vibration signals to determine whether the operation is in normal condition or abnormal condition, and by detecting or forecasting the cause in case the operation is in abnormal condition.

Method of controlling operation of rotary machines by diagnosing

The present stress in the turbine rotor is estimated at each control period, from the steam temperature and pressure at the turbine inlet. In addition, the future turbine inlet steam temperature or pressure is preestimated once every n.sub.T control cycles, for a given speed or load changing rate, making use of data concerning the changing rate of the turbine steam inlet temperature or pressure in relation with the change of the speed or load, which has been obtained by a learning of the past turbine operating condition. This future steam temperature or pressure at the turbine inlet is used as a factor for preestimating the future stress expected to be caused in the turbine rotor. The preestimation of the rotor stress is performed for a plurality of assumed speed or load changing rates. The turbine is controlled at the maximum speed increase-rate or load changing rate which would not cause the future stress preestimated over a given preestimation time to exceed a limit stress. An observation of the present stress is made at each control period to check whether the limit stress is not exceeded by the present stress.

Rotor-stress preestimating turbine control system

In an automatic control system, controls receive an input indicative of a deviation between feedback and demand signals and produce an output which in turn is applied to a plant to control it. A diagnostic device includes a model having an equivalent characteristic to the controls and receives the deviation signal. When a noise coming into the automatic control system is detected or when a deviation between the outputs of the model and controls is sufficiently small, no model operation is performed, and the output of the controls is determined as that of the model. However, when the deviation between the outputs of the model and the controls is large, the model is supplied with an input thereby performing a model operation. A resultant output of the model is then compared with the output of the controls to produce an alarm indicative of an abnormal state of the controls in accordance with a deviation between these outputs.

Diagnostic device for use with automatic control systems

A moving apparatus for a load lifts the load by the torque of a motor, and balances and holds the same with the aid of a mechanical brake when the apparatus stops. A timing device is incorporated in brake control so that when the apparatus stops in response to a signal indicating that a zero speed is designated, the mechanical brake is operated with a time lag after the receipt of the signal and, as soon as the brake is applied, the power supply to the motor is cut off. This arrangement remarkably reduces the impact of stopping upon the mechanical brake and drive, lessens the wear of the brake, permits reduction in size of the components and extends the service life of the components, thus providing an apparatus which saves power in comparison with conventional equipment.

Moving apparatus for a load

Apparatus for detecting the number of objects such as the number of persons located within a predetermined area. Ultrasonic wave is emitted toward the objects, the number of which is to be determined, and the reflected waves from the objects are received by a receiver. Among the received reflection waves, the waves having an amplitude greater than a predetermined peak value are derived as the useful reflection wave signal having a constant peak value. The number of the objects is determined based on the quantity of the derived reflection wave signals having the constant peak value. By emitting the ultrasonic wave for every unit time, the derived reflection wave signals having the constant peak value may be averaged by means of a smoothing circuit.

Apparatus for detecting the number of objects

An electromagnetic guidance system used, for example, for guiding a driverless mobile vehicle. For example, a two-core wire or cable is in the surface of a travelling course. The core conductors of the two-core wire are connected at its end so that current may circulates through the conductor. By detecting the magnetic flux induced by the circulating current by means of detecting coils mounted on the driverless mobile vehicle, the vehicle can be automatically run along the two-core wire without any change-over operation.

Electromagnetic guidance system

In a system for optically detecting with a plurality of light detecting elements a reflecting object in the form of long stripe disposed on the surface of a traveling path, the average value of the respective electric quantities derived from the light detecting elements is obtained through arithmetic operation and the reference value is automatically changed according to the degree of the surface being soiled, by multiplying the average value by a certain safety factor, so that accurate detection can be performed independent of the degree of the soil on the traveling path surface.

System for detecting reflecting objects

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Kure, Japan

Shigeyoshi Kawano