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.

IPC Classes  ?

• H02H 5/08 - Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal fluid pressure, liquid level or liquid displacement, e.g. Buchholz relays
• H01H 33/55 - Oil reservoirs or tanksLowering means therefor
• H01H 35/40 - Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow actuated by devices allowing continual flow of fluid, e.g. vane
• H01H 36/02 - Switches actuated by change of magnetic field or of electric field, e.g. by change of relative position of magnet and switch, by shielding actuated by movement of a float carrying a magnet
• H01F 27/40 - Structural association with built-in electric component, e.g. fuse

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.

IPC Classes  ?

• B01D 53/26 - Drying gases or vapours
• B01D 53/04 - Separation of gases or vapoursRecovering vapours of volatile solvents from gasesChemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases or aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
• H01F 27/14 - Expansion chambersOil conservatorsGas cushionsArrangements for purifying, drying, or filling