Electro-optical liquid level sensor
Patent 4354180 Issued on October 12, 1982. Estimated Expiration Date: 
December 19, 2000. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 19, 2000. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3120125 3384885 3448616 3553666 3882887 Frequency sensitive level detecting apparatus Liquid level indicator Patent #: 4155013 InventorAssigneeApplicationNo. 06/218454 filed on 12/19/1980US Classes:340/619, Optical sensor250/577, Volume or level340/514, Testing340/641, Signalling light element73/293With illuminationExaminersPrimary: Brigance, Gerald L.Attorney, Agent or FirmInternational ClassesG01F 23/284 (20060101)G01F 23/292 (20060101) G08B 29/04 (20060101) G08B 29/00 (20060101) AbstractA low liquid level electro-optical probe is made self-checking by providing the same with means for intercepting a portion of the usual light beam and constantly reflecting such portion to the usual receiving electro-optical transducer to constantly generate a low level electrical signal even when the probe is wet. Means are provided for boosting the signal to activate an alarm, failure of which will be indicative of failure or malfunctioning of one or more elements of the system. | |
