A variable vacuum capacitor is described in which oil inside the main bellows (21) is pumped through the bellows and through the oil circuit (8) of a heat exchanger by a pump (15). Water passes through coolant channels (6) of the heat exchanger, from inlet (7) to outlet (7′). The extendable capacitor drive shaft (14) is hollow and serves as a conduit, conveying the oil to the bottom of the (bellows 21), thereby ensuring a full circulation of the oil right through the bellows and then through the heat exchanger. Pump drive means (9) may be a gerotor hydraulic motor, coupled to a gerotor oil pump (15) via magnetic coupling (22). Pumping heat transfer fluid (oil) through the bellows allows the capacitor to operate at significantly higher currents and/or lower temperatures, and significantly extends the life of the device.

The present invention relates to a vacuum capacitor (1, 30) comprising an enclosure (9) to contain a vacuum dielectric medium, a first electrode (12) and a second electrode (13) separated by said vacuum dielectric medium, the enclosure (9) comprising a first conductive collar (2) in electrical contact with the first electrode (12) and a second conductive collar (3) in electrical contact with the second electrode (13), the first conductive collar (2) and the second conductive collar (3) being separated by an insulating element (4) of the enclosure (9), wherein the enclosure (9) exhibits at least one protruding edge (6), said protruding edge (6) being in electrical contact with the closest of the first conductive collar (2) or the second conductive collar (3), wherein the vacuum capacitor (1, 30) comprises at least one protection means (7, 37) covering on the outside of the vacuum enclosure the protruding edge (6), wherein the protection means (7, 37) is made at least partially of an elastomer, wherein at least the outer surface (7b, 37b) of the protection means (7, 37) is electrically conductive and is at the same electrical potential as the closest conductive collar to the protruding edge (6), and wherein the outer surface (7b, 37b) of the protection means (7, 37) has a radius of curvature greater than the radius of curvature of the protruding edge (6).

A vacuum variable capacitor includes a pre-vacuum enclosure for reducing a pressure differential across the bellows, wherein a drive is disposed outside the enclosures of the vacuum variable capacitor. The vacuum force load on the drive system can thereby be reduced, allowing faster movement of the movable electrode, faster capacitance adjustment of the vacuum variable capacitor and longer lifetimes of the device.

The present invention relates to a vacuum capacitor (1, 30) comprising an enclosure (9) to contain a vacuum dielectric medium, a first electrode (12) and a second electrode (13) separated by said vacuum dielectric medium, the enclosure (9) comprising a first conductive collar (2) in electrical contact with the first electrode (12) and a second conductive collar (3) in electrical contact with the second electrode (13), the first conductive collar (2) and the second conductive collar (3) being separated by an insulating element (4) of the enclosure (9), wherein the enclosure (9) exhibits at least one protruding edge (6), said protruding edge (6) being in electrical contact with the closest of the first conductive collar (2) or the second conductive collar (3), wherein the vacuum capacitor (1, 30) comprises at least one protection means (7, 37) covering on the outside of the vacuum enclosure the protruding edge (6), wherein the protection means (7, 37) is made at least partially of an elastomer, wherein at least the outer surface (7b, 37b) of the protection means (7, 37) is electrically conductive and is at the same electrical potential as the closest conductive collar to the protruding edge (6), and wherein the outer surface (7b, 37b) of the protection means (7, 37) has a radius of curvature greater than the radius of curvature of the protruding edge (6).

A variable capacitor includes an enclosure having first and second conductive collars separated by an intermediate electrically insulating element. A movable capacitor plate assembly is electrically coupled to the first conductive collar, and a fixed capacitor plate assembly is electrically coupled to the second conductive collar. An actuator extends into the enclosure for advancing and retracting the movable capacitor plate assembly relative to the fixed capacitor plate assembly. A hermetically sealed volume within the enclosure contains a dielectric fluid serving as a dielectric between a capacitor plate of the movable capacitor plate assembly and a capacitor plate of the fixed capacitor plate assembly. A flexible structure is provided to contain the dielectric fluid displaced when the movable capacitor plate assembly is advanced toward the fixed capacitor plate assembly.

A variable capacitor includes an enclosure having first and second conductive collars separated by an intermediate electrically insulating element. A movable capacitor plate assembly is electrically coupled to the first conductive collar, and a fixed capacitor plate assembly is electrically coupled to the second conductive collar. An actuator extends into the enclosure for advancing and retracting the movable capacitor plate assembly relative to the fixed capacitor plate assembly. A hermetically sealed volume within the enclosure maintains a vacuum or a liquid serving as a dielectric between a capacitor plate of the movable capacitor plate assembly and a capacitor plate of the fixed capacitor plate assembly. At least one capacitor plate comprises a coiled cylindrical plate having a having a greater height at a center portion of the capacitor plate coil and a lower height at an outer portion of the capacitor plate coil.

A base plate has pressure introducing holes at positions facing a diaphragm support portion. A thickness portion (thick portion) of the diaphragm support portion and a sensor base joined to the diaphragm support portion thus serves as a heat dissipating or absorbing portion and hinders the transfer of thermal energy of a measured medium to a sensor diaphragm.

A variable vacuum capacitor is described in which oil inside the main bellows (21) is pumped through the bellows and through the oil circuit (8) of a heat exchanger by a pump (15). Water passes through coolant channels (6) of the heat exchanger, from inlet (7) to outlet (7). The extendable capacitor drive shaft (14) is hollow and serves as a conduit, conveying the oil to the bottom of the (bellows 21), thereby ensuring a full circulation of the oil right through the bellows and then through the heat exchanger. Pump drive means (9) may be a gerotor hydraulic motor, coupled to a gerotor oil pump (15) via magnetic coupling (22). Pumping heat transfer fluid (oil) through the bellows allows the capacitor to operate at significantly higher currents and/or lower temperatures, and significantly extends the life of the device.

A variable capacitor includes an enclosure having first and second conductive collars separated by an intermediate electrically insulating element. A movable capacitor plate assembly is electrically coupled to the first conductive collar, and a fixed capacitor plate assembly is electrically coupled to the second conductive collar. An actuator extends into the enclosure for advancing and retracting the movable capacitor plate assembly relative to the fixed capacitor plate assembly. A hermetically sealed volume within the enclosure maintains a vacuum or a liquid serving as a dielectric between a capacitor plate of the movable capacitor plate assembly and a capacitor plate of the fixed capacitor plate assembly. At least one capacitor plate comprises a coiled cylindrical plate having a having a greater height at a center portion of the capacitor plate coil and a lower height at an outer portion of the capacitor plate coil.

A base plate has pressure introducing holes at positions facing a diaphragm support portion. A thickness portion (thick portion) of the diaphragm support portion and a sensor base joined to the diaphragm support portion thus serves as a heat dissipating or absorbing portion and hinders the transfer of thermal energy of a measured medium to a sensor diaphragm.