<p>A capacitor has three cases (20), each of which is placed inside an upper part (12) of an enclosure (4) which is associated to it. Each case is fixed on an inner wall of the part by using a curing material e.g. polymer resin, that is interposed between the case and the enclosure for sealing and bonding between them. Each case is fixed inside the part (12) of the enclosure and is positioned vertically in the enclosure. Each case comprises an inner annular cylindrical portion delimiting an opening that is closed by a diaphragm (14).</p>
