Abstract: A breather device (1) for dehumidifying air to be supplied into an expansion vessel (103) of a power electrical device (100), said breather device comprising an air demoisturizer unit (2) including one or more tanks (21), each tank having an internal volume (20) accommodating a regenerable moisture absorbing substance and a heater (23) for regenerating said moisture absorbing substance, at least a first opening (25) configured to put the internal volume of said tank in fluid-dynamic communication with the external environment and at least a second opening (22) configured to allow a flow of air to exit from the internal volume of said tank towards another section of said breather device.

Abstract: A safety device is disclosed for a power transformer containing a cooling liquid, and can include a shaped body having an inner chamber which is suitable to be at least partially immersed in cooling liquid and inside which gas can accumulate; a first floating element and a second floating element suitable to be at least partially immersed in and moved by cooling liquid; and a switch suitable to be actuated by the first floating element when the gas accumulated is such that the level of the cooling liquid in the inner chamber reaches a predetermined first threshold level and by the second floating element when the gas accumulated is such that the level of the cooling liquid in the inner chamber reaches a lower predetermined second threshold level, respectively. The first and second floating elements can be mounted on and move linearly relative to one or more corresponding guiding supports.

Abstract: An air dehydrating breather assembly and method provide dehumidifying air suitable to be supplied into oil expansion vessels used in electrical devices. The air dehydrating breather assembly includes first and second air demoisturizer units respectively associated with two corresponding oil expansion vessels. The first air demoisturizer unit includes a first tank housing moisture absorber and a second tank housing moisture absorber alternatively providing dehumidified air. The second air demoisturizer unit includes a third tank housing moisture absorber providing dehumidified air. Sensors are associated with the first, second and third tanks to detect the level of saturation of their moisture absorbers. An electronic processing unit is operatively associated with the sensors for routing dehumidified air to the associated oil-expansion vessels from the tanks whose moisture absorbers are not saturated.

Abstract: A safety device is disclosed for a power transformer containing a cooling liquid, and can include a shaped body having an inner chamber which is suitable to be at least partially immersed in cooling liquid and inside which gas can accumulate; a first floating element and a second floating element suitable to be at least partially immersed in and moved by cooling liquid; and a switch suitable to be actuated by the first floating element when the gas accumulated is such that the level of the cooling liquid in the inner chamber reaches a predetermined first threshold level and by the second floating element when the gas accumulated is such that the level of the cooling liquid in the inner chamber reaches a lower predetermined second threshold level, respectively. The first and second floating elements can be mounted on and move linearly relative to one or more corresponding guiding supports.

Abstract: A safety apparatus and method for monitoring a liquid-filled power transformer wherein there is provided a sensing device associated with an electronic unit. The sensing device is suitable to be at least partially immersed into liquid and includes at least one movable part displaceable by movements of the liquid. The electronic unit detects signals indicative of an actual position of the movable part and is arranged to provide, based on the detected signals, data related to actual conditions of the transformer and/or of its cooling liquid.

Abstract: An air dehydrating breather assembly and method provide dehumidifying air suitable to be supplied into oil expansion vessels used in electrical devices. The air dehydrating breather assembly includes first and second air demoisturizer units respectively associated with two corresponding oil expansion vessels. The first air demoisturizer unit includes a first tank housing moisture absorber and a second tank housing moisture absorber alternatively providing dehumidified air. The second air demoisturizer unit includes a third tank housing moisture absorber providing dehumidified air. Sensors are associated with the first, second and third tanks to detect the level of saturation of their moisture absorbers. An electronic processing unit is operatively associated with the sensors for routing dehumidified air to the associated oil-expansion vessels from the tanks whose moisture absorbers are not saturated.

Abstract: Process for controlling a dryer, suitable of dehumidifying air entering oil expansion vessels used in electrical appliances, in which a protective casing of the dryer surrounds at least two dehumidifying tanks or vessels containing an absorption device suitable to absorb air humidity coming from the outside and which can be thermally regenerated by resistors. The resistors are connected with a load cell, suitable to determine the state of saturation of the absorption device, so that detecting by the load cell of a measured mass value greater than a predefined threshold value (MFS) operates the resistors in order to regenerate the absorption device to the original state.