Abstract: A variable optical attenuator comprising a separation/combination birefringent element, fixed polarization rotation means, a convex lens, variable polarization rotation means, and a mirror which are arranged in that order. The fixed polarization rotation means has a compensation film Faraday element placed in a cylindrical permanent magnet, and the variable polarization rotation means has a base film Faraday element that is placed outside the cylindrical permanent magnet, and an electromagnet applying a variable magnetic field thereto. Thereby, both the Faraday elements are magnetized in directions different from each other.

Abstract: A variable optical attenuator comprising a separation/combination birefringent element, fixed polarization rotation means, a convex lens, variable polarization rotation means, and a mirror which are arranged in that order. The fixed polarization rotation means has a compensation film Faraday element placed in a cylindrical permanent magnet, and the variable polarization rotation means has a base film Faraday element that is placed outside the cylindrical permanent magnet, and an electromagnet applying a variable magnetic field thereto. Thereby, both the Faraday elements are magnetized in directions different from each other.

Abstract: The invention provides a sealing apparatus hardly causing a fire and capable of ensuring a stable sealing performance over a long time is obtained. The sealing apparatus is provided at an inlet/outlet for a metal strip 22 in a bright annealing furnace 21 to shut off atmospheric gas in the furnace from the outside air. A pair of elastic rolls 30a, 30b push both sides of the metal strip 22. The boundaries between the elastic rolls 30a, 30b and pushing members 25a, 25b are hermetically sealed by rigid rolls 26a, 26b. The elastic rolls 30a, 30b and the pushing members 25a, 25b are made of an elastic material, and the rigid rolls 26a, 26b are made of a metal. Nonwoven fabrics 27a, 27b are interposed between the rigid rolls 26a, 26b and the pushing members 25a, 25b.

Abstract: A seal assembly is located at an entrance and/or an exit of a heat treatment furnace with a side plate for heat treating a continuously fed metallic strip. The furnace includes an elastic rotating roll which has a roll body and a roll shaft, and is engaged with an elastic pad fixed on a surface of a seal plate and the metallic strip to seal an inside of the furnace against outside air. The seal assembly includes at least two closely-set slip disks arranged in an axial direction of an end side of the roll body, and at least one elastic disk engaging the side plate of the furnace. The at least two slip disks and at least one elastic disk are fitted over the roll shaft between the side plate of the furnace on which the elastic rotating roll is rotatably mounted and the roll body of the elastic rotating roll such that the at least two slip disks and the at least one elastic disk are in surface contact with each other.

Abstract: A sealing apparatus securely seals the inlet and outlet of an atmosphere heat treatment furnace. A pair of elastic rolls 26 and a pair of additional elastic rolls 26 hold a metal strip so as to seal the inlet and outlet of the atmosphere heat treatment furnace which continuously performs bright annealing of the metal strip in a combustible atmosphere gas including hydrogen gas. A pair of intermediate rolls are disposed between the elastic rolls and the additional elastic rolls. The outer peripheral surface of the elastic roll is sealed by a seal plate. By multi-stage sealing, the outside air can be shut off securely from the atmosphere of the furnace.

Abstract: A seal assembly (3) located at an entrance and/or exit of a heat treatment furnace for heat treating a metallic strip (S) with no formation of oxide films on the surface thereof, using an atmospheric gas containing hydrogen gas and including an elastic rotating roll (6) being pressedly engaged with an elastic pad (5) fixed on the surface of a seal plate (4) and the metallic strip (S) to seal the inside of the furnace against the outside air, wherein elastic members (9) being provided in through-holes (2b) formed through a side plate (2a) of a furnace wall (2) at positions corresponding to both side edges of the elastic pad (5), and elastic member-moving mechanisms (10) being provided for pressedly engaging the elastic members (9) with the sides of the elastic pad (5); at least two closely-set slip disks (7) arranged in an axial direction of the side of a roll body (6c) and an elastic disk (8) being fitted over a roll shaft (6a) between the side plate (2a) of the furnace wall (2), on which the elastic rotating

Abstract: The sealing apparatus of the present invention is intended to enhance the sealing performance and to reduce the rotation loads at the end surfaces of elastic rolls. A sealing apparatus 20 is provided to hermetically seal the inlet/outlet of a bright annealing furnace 22, through which a metal strip 21 is passed. Since the metal strip 21 is held between a pair of elastic rolls 23 on both sides of the strip, the metal strip can be passed through while hermetic sealing is maintained. A covering member 34 and an end surface sealing member 39 made of elastic materials are disposed between the end surface of the elastic roll 23 and the side wall 26 of a casing 25 to attain reliable sealing. A first supporting member 35, a second supporting member 36. an outer bearing 37 and inner bearings 38 made of rigid materials are disposed between the covering member 34 and the end surface sealing member 39 to reduce the rotation loads of the rolls.

Abstract: A seal assembly of the invention located on entrance and exit sides of a heat treating furnace for a metallic strip. The seal assembly is formed of a housing having a furnace wall and a side plate, a seal sheet fixed at one end to the side plate and supported in place with flexibility, an elastic seal pad fixed to a surface of the seal sheet, and an elastic rotating roll held by the furnace wall at longitudinal ends and pressed against the elastic seal pad and a metallic strip to be treated. The elastic seal pad has a surface formed of a material with a limit oxygen index LOI of 26 or more and a hardness of 10 to 50 as measured according to JIS S6050. Also, a plurality of pressure applying mechanisms is attached to the side plate.

Abstract: A danger of explosions or fires caused by a spark of static electricity in sealing portions of compartment gateways of continuous annealing furnaces to perform bright annealing or oxidation-free annealing of metal strips, continuous painting equipments, and the like wherein a flammable atmospheric gas having a danger of explosions or fires is used, is prevented, and the formation of abrasions or scratches on the strip surface is prevented. In the sealing portions of the gateways, an elastic pad (17) including an electroconductive non-woven fabric having carbon-containing fibers, fibers having chemically formed polypyrrole as electron-conjugated electroconductive polymer, fibers made by treating acrylic fibers with a divalent copper compound and a sulfur-containing compound alone, or fibers having these fibers as the major component, provided on a surface of a sealing hardware (16), a surface of which has an electrical resistivity value of from 10.sup.-3 to 10.sup.6 .OMEGA..multidot.

Abstract: A seal device is provided in each comparted entrance and exit of a furnace for continuous thermal treatment of a metallic strip using a flammable atmospheric gas. The seal device is provided with seal members for sandwiching the metallic strip to seal the flammable atmospheric gas, seal hardwares each being fixed to a furnace body and pressed by the seal member, and seal mechanisms for sealing the flammable atmospheric gas from the seal member at an urgent time. A differential distribution detector having heat-receiving portions formed of a metallic pipe filled with air is placed over the whole width outside the seal member. When a leaked atmospheric gas is ignited outside the seal member, a rapid temperature increase in the heat-receiving portions is detected to give a signal, whereby running of the metallic strip is stopped, and the seal mechanism is operated to shut off the seal device from the inside of the furnace body. Then, a nitrogen gas is fed into the seal device.

Abstract: A switching node in a label multiplexing type switching network includes a switch for selectively coupling input logical communications paths and output logical communications paths with each other, m permanent logical communications paths being included in the input logical communications paths where m is an integer larger than or equal to 1, n permanent logical communications paths being included in the output logical communications paths where n is an integer larger than or equal to 1. The switch node includes a call control unit for receiving connection-oriented type information through any of the input logical communications paths and for controlling the switch so that the connection-oriented type information are selectively transferred to the output logical communications paths via the switch on the basis of routing address information related to the connection-oriented type information.