Accession Number : ADD009750

Title :   Leak Detector.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Graham,Edward

Report Date : 02 Jul 1982

Pagination or Media Count : 12

Abstract : This document describes a liquid detector or liquid differentiator which functions to detect the presence of a liquid such as water or fuel oil in a missile or other device. A light emitting diode is used as a light detector. The light source and light detector are separated by a first and second light refracting medium. The first medium is chosen to have a critical index of refraction eta 1 greater than 1.0 and a critical angle of incidence theta at which refraction ceases and reflection begins. The second medium is chosen to have an index of refraction eta 2 such that light at the interface between the first medium to the second medium is totally reflected. The second medium can be an air gap such that when no foreign fluid is present in the air gap the light beam from the light emitting diode is reflected at the interface of the first and second mediums. When a foreign fluid is introduced into the second medium or air gap by a leak, eta 2 changes to be greater than eta c and the light beam is transmitted through the second medium and detected by the photodetector, indicating the presence of a leak. (Author)

Descriptors :   *Patent applications, *Light emitting diodes, *Detectors, *Leakage(Fluid), Fuel oil, Leak detectors, Refractive index, Reflection, Interfaces, Angle of incidence, Photodetectors, Light sources, Inventions, Air gaps

Subject Categories : Electrooptical and Optoelectronic Devices
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE