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Browse Prior Art Database

Optical Liquid Level Sensor

IP.com Disclosure Number: IPCOM000052843D
Original Publication Date: 1981-Jul-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Gupta, OR: AUTHOR [+2]

Abstract

As applications for fiber optics are increasing, the development of sensors has become very important. This arrangement provides a means by which the liquid level can be sensed without any moving parts or electronic interfaces.

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Optical Liquid Level Sensor

As applications for fiber optics are increasing, the development of sensors has become very important. This arrangement provides a means by which the liquid level can be sensed without any moving parts or electronic interfaces.

A direct means of detecting liquid level without using any electronic interface and logic is attained as follows: Optical signals in some code form are transmitted through the transmitting fiber 1 toward the glass plates 3 and 4. The receiving fiber 2 receives the reflected optical signals from the two glass plates 3 and 4. The glass plate 3 and glass plate 4 are at a right angle to each other and are oriented with respect to sender fiber 1 and receiving fiber 2 such that the optical signals meet the plate at substantially a 45 degree angle. This simple arrangement provides the unique capability of sensing the liquid level in a vessel.

When the liquid is above the sensor, optical signals from the transmitting fiber 1 are totally reflected by the glass plates 3, 4, thereby providing a signal indicative of the proper liquid level. Referring to Fig. 1, it can be seen that the index of refraction of the water and glass is the same. Thus, there is no refraction of the light beam. This, coupled with the 45 degree angle of incidence, provides nearly total reflection from the plates 3 and 4. On the other hand, if the liquid is below the optical sensor, most of the light from the transmitter fiber 1 passes through the tr...