| 摘要 |
A liquid level gauge for a tank, especially a pressurized railway tank car, has a housing with a bottom opening mounted at a top opening of the tank. A horizontal shaft is rotatably mounted in the housing between opposed walls having parallel flat vertical inner surfaces. A sprocket is fixedly mounted on the central part of the shaft, on each end of which is fixedly mounted a ring magnet spaced from one of these walls. Complementary ring magnets are rotatably mounted outside but adjacent these opposed walls. The four ring magnets constitute a pair of magnetic drives. A track and cable guide assembly, supported in the tank, extends from the bottom portion of the tank. A perforated tape is trained over the sprocket on the shaft and another sprocket rotatably mounted in the bottom portion of the tank so that the tape is under tension. A probe assembly connected to the tape moves vertically when the sprocket in the housing is rotated. The probe assembly senses a liquid-vapor interface and rides in the track and cable guide assembly. An electric cable connected to the probe extends up to the housing. Pulleys and cables keep the electrical cable under tension. One magnetic drive is rotated to move the tape and operate the other magnetic drive that has its complementary ring magnet connected to a device to indicate the position of the probe.
|
