Abstract: A shield method includes the steps: providing a first cylindrical frame 31 at a position where an entrance 12 is to be formed in an inner surface of an earth retaining wall 11 of a shaft 1; excavating a horizontal hole 5 in the underground by a shield machine 2, and sequentially adding and building, in the excavation direction, a plurality of segments 4 on an inner diameter side of the horizontal hole 5 while forming the entrance 12 in the shaft 1; temporarily stopping water from a gap between the entrance 12 and the shield machine 2, and removing excavated soil and pieces 6 that enter the first cylindrical frame 31 as the entrance 12 is formed; and coupling a second cylindrical frame 32 having a sealing member 35 attached thereto to an inner open end of the first cylindrical frame 31.

Abstract: An object to provide a vent pipe isolation balloon for a liquefied gas storage tank, which has excellent physical strength, inflatability, and durability at cryogenic temperatures, and a vent pipe isolation device including the balloon. The vent pipe isolation balloon has inner and outer membranes made of silicon rubber, and a reinforcing substrate sandwiched between the inner membrane and the outer membrane. The balloon has an outer shape of a cylindrical shape or a truncated cone shape with both ends opened, and is inflated when an inert gas is injected into the balloon with the openings sealed. The reinforcing substrate is composed of a fiber bundle and has a network structure.

Abstract: A shield method includes the steps: providing a first cylindrical frame 31 at a position where an entrance 12 is to be formed in an inner surface of an earth retaining wall 11 of a shaft 1; excavating a horizontal hole 5 in the underground by a shield machine 2, and sequentially adding and building, in the excavation direction, a plurality of segments 4 on an inner diameter side of the horizontal hole 5 while forming the entrance 12 in the shaft 1; temporarily stopping water from a gap between the entrance 12 and the shield machine 2, and removing excavated soil and pieces 6 that enter the first cylindrical frame 31 as the entrance 12 is formed; and coupling a second cylindrical frame 32 having a sealing member 35 attached thereto to an inner open end of the first cylindrical frame 31.

Abstract: An object to provide a vent pipe isolation balloon for a liquefied gas storage tank, which has excellent physical strength, inflatability, and durability at cryogenic temperatures, and a vent pipe isolation device including the balloon. The vent pipe isolation balloon has inner and outer membranes made of silicon rubber, and a reinforcing substrate sandwiched between the inner membrane and the outer membrane. The balloon has an outer shape of a cylindrical shape or a truncated cone shape with both ends opened, and is inflated when an inert gas is injected into the balloon with the openings sealed. The reinforcing substrate is composed of a fiber bundle and has a network structure.

Abstract: For a bearing mechanism, a pair of oil seals are installed within an outer cylindrical housing and elastically encircle a rotating or reciprocating shaft extending concentrically through the housing. Each of the oil seal is made of rubber or synthetic resin and has a prop ring made of steel wire extending underground through a radially outer portion of the oil seal. The prop ring is partly cut out and thus provides a radially outwardly directed elasticity for close adhesion to the inner surface of the housing. The radially outer portion of the oil seal extends in a radially inward direction to form an oil sealing lip and a dust sealing lip, with a narrow dog-legged portion at an intermediate portion of the oil seal which permits the oil seal to be flexible in a radial direction. An additional seal having substantially a similar elements and structure may be installed as a dust seal.