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: A volumetric compressor of the type comprising a pair of rotors cooperating with each other and housed inside a compressor body, in which it is possible to identify a first flange, arranged on the suction side of the compressor body, and a second flange, arranged on the delivery side of the compressor body, suited to couplingly house a suction head and a delivery head of the volumetric compressor, wherein the suction head is provided with a first counterflange, suited to be connected to the first flange, and comprises a coupling element for connection to a suction pipe, or a coupling element for connection to a suction pipe in combination with a motor unit, and the delivery head is provided with a second counterflange, suited to be connected to the second flange, and comprises a coupling element for connection to a delivery pipe, or a coupling element for connection to a delivery pipe in combination with an oil separator.

Abstract: Volumetric compressor comprising a casing forming an intake chamber and a delivery chamber, a pair of screw rotors coming between the intake chamber and delivery chamber, a container for containing a high-pressure fluid, associated with the casing, a capacity regulating device associated with the casing, which includes a slide valve cooperating with the rotors, a fluid-operated actuator comprising a cylinder complete with a bottom and a head with a through hole for the passage of a stem having one end associated with a piston sliding inside the cylinder and the opposite end associated with the slide valve, channels obtained in the cylinder, a pipe for delivering the fluid, which connects the container to one of the channels and outlets for the fluid which connect the channels to the intake chamber, shut-off solenoid valves installed inside the outlets and a control unit connected to the shut-off solenoid valves.