| 摘要 |
<p>676,397. Protective cut-out arrangements; fluid actuation of switches. MICAFIL, Ltd. Sept. 4. 1950. [Sept. 7, 1949] No. 21786/50. Class 38 (v). A protective device for an electrical apparatus immersed in an insulating liquid has one or more floats 3, 4, which upon the formation of gas, swivel to close contacts in indicating and tripping circuits, and is provided with a remotely-controlled valve to discharge any gas which may have collected in the device. In the Figure, the device has floats 3, 4 pivotally mounted on a fixed bracket 7 by means of levers 5, 6. The valve comprises a cylindrical bore 12 in which a valve piston 13 may be moved against the compression of a spring 19 by the armature 17 of an electromagnet 16. When the coil of the electromagnet 16 is energized, the piston 13 is moved downwardly out of the bore 12 so that any gas in the main chamber of the device may escape through the bore 12 into a chamber 14 and thence via a pipe 15 into an expansion vessel 10 of the apparatus. Capillary action in the annular space between the piston 13 and the bore 12 assisted by the head of cool liquid in pipe 15 provides an adequate seal to prevent leakage of gas when the valve is closed. For testing purposes a two-armed lever 20 is fixed to the valve piston 13 so that when the electromagnet is energized the floats are depressed to check their operation and that of the protective circuits. Instead of an electromagnet, an electric motor, pneumatic or hydraulic means, a chain transmission, linkage or gearing may be used to operate the valve from a remote point.</p> |
