PRESSURE RELIEF DEVICES FOR POWER TRANSFORMERS (with electric contacts)
GENERAL FEATURES When it is required to limit the force rise inside a tank, in order to prevent an overindulgenceive mechanical stress of the walls, it is indispensable to use a safety valve set at a precise over twitch value. The tank of oil-immersed transformers is usually fit with this kind of defend device; as matter of fact, in case of shortcircuit due(p) to an insulation failure, the dielectric arc between alive split vaporises the surrounding insulating fluid which generates a quick rise of the pressure inside the tank, with the risk of permanent deformations, or, even, of the failure of the tank walls with the sequent flow-out of hot oil. Due to the rapidity of this event, it is necessary to mount on the transformer an adequate protecting device which relieves quite suddenly the excess of pressure generated inside the tank by the above mentioned failure. Our insistence Relief Devices VP have this protective function.
WAY OF WORKING The counselling of working of above device is very simple: individually time the pressure inside the transformer tank reach the direct pressure of the PRD, the shutter lift slowly from its rest berth disjoining from the main tightening gasket (pos 9 of the attached sketch); in this take aim the excess of pressure cant be released in the environment, being the shutter still in contact with the immaterial gasket (pos 10 of the attached sketch). Now the internal overpressure operates on the square internal surface of the shutter, which is bigger than the initial surface: consequently, the loudness acting on the shutter is much higher than the spring-load on the other side; this brings to a quick and high lifting of the shutter followed by an equally fast reclosure as the excess of pressure is released in a very short time through the big opening created by the shutter lifting. GENERAL FEATURES of our VP devices Body, connecting recess and shutter in cast aluminium, paint...If you want to get a full essay, order it on our website: Orderessay
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