| 摘要 |
An indicating device is disclosed for showing the level of a fluid in a container. A transparent rod having a sensing end is immersed in the fluid when the container is filled above a predetermined level. The sensing end is shaped to cause a substantially total reflection of a beam of light projected in the rod from an opposite end of the rod when the sensing end is not in contact with the flowable substance. A light source and photoelectric detector are arranged at the opposite end of the rod and a circuit is connected to the photoelectric detector for detecting when a predetermined amount of reflection occurs and also for preventing response of the device to slopping of the fluid to and fro in the container.
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