Abstract: A system clarifies the damaged state of a plant, and estimates the life expectancy of the plant so as to administer the integrity of the plant. The system includes an apparatus for estimating the life expectancy of each of various pieces of component constituting the plant, a data base controlling apparatus, an apparatus for estimating the life expectancy of the entire plant, and a plant life extension and evaluation apparatus. The system is capable of making a specific proposal of a life extension plan which is necessary to and effective for the extension of the entire plant, and which is proposed including economical evaluation, thereby facilitating the conservation of the integrity of the plant, and also facilitating the maintenance and control thereof.

Abstract: The life expectancy of a mechanical structure that undergoes repeated loading is estimated by determining the maximum crack length on the surface of the structure. The maximum length of the cracks on the surface of the structure is related to the life ratio of the structure, wherein the life ratio is a ratio of the number of loads the structure has undergone to the number of loads the structure will undergo until failure. An optical system is used to measure the crack length of the cracks on the surface of the structure being inspected. A statistical distribution of greatest length cracks for a sampling of areas within a larger area can be made. Apparatus is provided to statistically process such distribution data to obtain a statistically estimated maximum length crack for the larger area. The maximum crack length determination can be used to estimate the life expectancy of the structure from the relationship between crack length and life ratio.

Abstract: A method system for assessing the safety of a rotor of a shrinkage fitted type wherein an opening displacement of a crack is determined an elastic-plastic fracture method and a reduction in shrinkage fitting force is calculated based on the crack opening displacement. The safety of the rotor is assessed based on the reduction in shrinkage fitting force caused to occur by the opening of the crack.

Abstract: A method of starting a turbine having a shrinkage-fitted rotor provided by shrinkage-fitting discs onto a shaft comprises the steps of raising the temperature of the rotor above a predetermined temperature determined from a physical value of the material constituting the rotor and, thereafter, raising the rotational speed of the turbine from the turning speed to the rated speed, whereby the centrifugal stress on raising the speed acts on the discs in a state wherein the value of fracture toughness of the discs fitted on to the shaft has increased.

Abstract: A method and apparatus for monitoring cracks of a rotatable body by detecting cracks by measuring accoustic emission signals and evaluating the depth of cracks from the result of the comparison of assumed vibrations of the rotatable body and its measured vibrations. By this method and apparatus not only the beginning of cracking of the rotatable body, but also the progress of cracking on an online basis can be detected and monitored.

Abstract: A stage structure of an axial turbine includes a stationary inner ring, a stationary outer wall, a row of stationary blades mounted on the stationary inner ring and outer wall, a row of moving blades, and a shroud ring mounted on the tips of the moving blades. An annular solid substance, disposed immediately downstream of an axial gap formed between an axial end of the shroud ring and surface of the outer wall axially facing the axial end of the shroud ring, reduces an expansion space provided immediately downstream of the axial gap, whereby circulation of an ejection flow from a main stream through the axial gap is reduced so that the turbine stage efficiency is improved. The annular solid substance may be a ring fixed to the stationary outer wall, a protrusion or a cylinder formed by a portion of the outer wall.

Abstract: Disclosed is a method for detecting the condition of a crack generated in a rotor of a rotary machine during an operation thereof to check whether the crack is developing or not. The number of revolutions of the rotor and oscillations of journal end portions of the rotor born by the bearings are continually detected. The detection of the crack condition is made on the basis of the detected signal corresponding to the waveform of each half of at least one cycle of the detected rotor oscillation. Disclosed also is an apparatus for carrying out the method.

Abstract: A water-resisting and oil-resisting laminated sheet, the oil resistance of which is not reduced by alcohol, prepared by laminating an ethylene-vinyl acetate copolymer layer and a paper, which paper is coated or impregnated with a liquid or a coating composition and then dried by heating. The copolymer layer has a vinyl acetate component of 10 to 30 mole %, a melt flow index of 2 to 20, and a thickness of 10 to 50.mu.. The liquid is in an amount of 0.5 to 5% by weight to the paper as solid component and is prepared by mixing an aqueous solution or an aqueous dispersion of an oil-resisting polymer such as polyvinyl alcohol, etc., with an aqueous dispersion of a perfluoroalkyl acrylate copolymer at 3:7 to 7:3 by solid component ratio, adding thereto 0.1 to 3% by weight of a penetrating agent such as polyalkylene glycol or derivatives thereof, and diluting with water.

Abstract: A steam turbine rotor shaft made of precipitation-hardened forged austenite steel, comprising first, second and succeeding layers of build-up welding provided on an outer surface of a bearing portion of a journal section in the rotor shaft, the first layer being provided by use of a welding rod of Ni base alloy, the second and succeeding layers being provided by use of a welding rod of low alloy steel which layers have better bearing characteristics than those of the austenite steel.

Abstract: A main steam inlet structure of a steam turbine has two inlet tubes which are separable from an inner casing and an outer casing of the turbine and are arranged concentrically with a spacing therebetween to constitute an inflow passage for main steam are connected at one end to the outer casing and at the other end to the inner casing, by seal rings. Cooling steam extracted from turbine stage midway is supplied to a cooling steam passage of the spacing formed between the two inlet tubes, thereby cooling the inner inlet tube.

Abstract: A pigmented coating composition comprising a pigment consisting of kaolin clay or TiO.sub.2 or the mixture thereof, or a pigment wherein Al(OH).sub.3 is further blended therein, and also comprising an adhesive consisting of crosslinkable ethylenevinylacetate copolymer aqueous emulsion combined with a crosslinker or of crosslinkable polyacrylate copolymer aqueous emulsion combined with a crosslinker of water-soluble polymaidepolyurea resin and the pigment above and the mixed adhesive are formulated in a ratio of 85:15 to 70:30 as coating composition. This pigmented adhesive composition is primed on the substrate paperboard. Thereby finished ovenable paperboards, being capable of retaining the brightness at least 45% against the heat-treatment of 250.degree. C. for 20 minutes, is free from scorch even in an electrically heating oven and is excellent in adhesion to extrusion-laminating plastic layer.

Abstract: A bearing consisting of a pivot having a semi-spherical or hemi-spherical end portion formed with helical grooves and immersed in lubricating oil, and a cup bearing element also immersed in lubricating oil for supporting the pivot. A plurality of helical grooves disposed on the semi-pherical end portion are formed and arranged such that the lubricating oil is supplied under pressure to sliding surfaces of the pivot and the cup bearing element. An annular recess is formed on the intake side of the grooves.