| 摘要 |
<p>A pump for pumping insulating oil for oil-filled electric cables in which a driven piston is within and spaced from a tubular bellows which is surrounded by an enclosure. The bellows forms a chamber with the enclosure which contains the cable oil, and the bellows prevents contact of the mechanical parts of the pump, other than an intake valve and a delivery valve, with the cable oil. Preferably, the space between the piston and the bellows is filled with oil to transmit motion of the piston to the bellows. The delivery valve is urged closed by a spring, and the intake valve has an element made of lightweight materials and is held closed by gravity and the cable oil pressure but opens by reason of cable oil pressure reduction and the static pressure of the cable oil fed to the intake valve. Also, a plurality of such pumps operable by a single drive mechanism and a method for evacuating gas from the pump and pump lines in which the delivery valve is operated by a magnetic field external to the valve.</p> |
