LIQUID LEVEL MONITOR

• US 3,808,887 A
• Filed: 02/29/1972
• Issued: 05/07/1974
• Est. Priority Date: 02/29/1972
• Status: Expired due to Term

• Current Assignee: Albert T. Buttriss
• Original Assignee: Albert T. Buttriss
• Inventors: Buttriss, Albert T.
• Primary Examiner(s): Queisser, Richard C.
• Assistant Examiner(s): Yasich, Daniel M.
• Application Number:
  US05/230,276
• Time in Patent Office: 798 Days
• Field of Search: 73/293,313,327 116/118R 340/244R,380 317/235N
• US Class Current: 73/293
• CPC Class Codes: G01F 23/2922 with light-conducting sensing elements, e.g. prisms
• CPC Class Codes: Y10S 116/05 using light guides

Abstract

A liquid level monitor for monitoring the level of liquids in a remote or shielded container and providing a signal proportional to any one of an infinite number of levels within a given range. The monitor has a sheet sealingly engaging an aperture in the container which extends vertically over the range of levels to be monitored. An external light source provides light which shines upon the light transmitting material. An external lens may be used to direct any light reflected by the light transmitting material, the intensity of which will be inversely proportional to liquid level, to a light receiving station. The light received at the receiving station is then conducted, preferably by means of fiber optics, to a remote monitoring station. The monitoring station may be a visual display or may convert the light received into a signal, proportional to intensity, for use by an indicating or controlling device. The level of liquid in the container and changes thereto may also be used to monitor the stability of the device to which the container is mounted.

Claims

1. A device for providing an electrical signal substantially proportional to liquid level, over a predetermined range, in a container, said device comprising:

a light transmitting sheet member sealingly engaging a substantially vertical aperture in said container, said aperture extending vertically over the predetermined range and being of substantially constant horizontal dimension, said sheet member being of a material which will reflect external light if exposed to gas at its interior surface and will transmit external light if exposed to liquid at its interior surface;

a source of light external of said container for supplying a substantially equal intensity of light upon the exterior surface area of said sheet member;

a light collection station mounted to said sheet member external of said container for collecting the light reflected by said sheet member;

a shield for shielding said collection station from said source;

a monitoring station in optical communication with said collection station, said monitoring station including means for providing an electric signal proportional to the intensity of light reflected from said sheet member and means for optically interconnecting communicating said collection station and said monitoring station.

2. The device of claim 1 additionally comprising a lens integrally formed with said light transmitting member and mounted exteriorly of said container for directing substantially all of the light reflected by the exterior surface of said sheet member to said collection station. 3. The device of claim 2 wherein the means of optical communication between monitoring and collecting station comprises a fiber optics conducting member.

4. The device of claim 2 wherein said member is oriented substantially vertically with respect to the ground, said aperture being of a substantially constant horizontal dimension whereby said member would reflect and transmit light in a ratio which is substantially proportional to liquid level over the predetermined range.

5. The device of claim 3 wherein said collection station comprises one end of said fiber optics conducting member.

6. The device of claim 3 wherein said source of light is a solid state light emitter.

7. The device of claim 6 wherein said member, said shield, said lens, said collection station and said source of light are formed in a totally encapsulated unit.

8. A device for indicating the level of liquid in a container over a predetermined range, said device comprising:

a light transmitting sheet member sealingly engaging an aperture in a substantially vertical wall of said container, said aperture extending vertically over said predetermined range, said sheet member of a material which reflects exterior light if exposed to gas at its interior surface and transmits exterior light if exposed to liquid at its interior surface;

a source of light exterior to said container, said source providing light rays which shine upon the exterior surface of said sheet member;

a light collection station exterior of said container for receiving light rays reflected by the exterior surface of said sheet member; and

a lens mounted said sheet member exterior of said container for directing substantially all light reflected by the exterior surface of said sheet member upon said light collection station.

9. The device of claim 8 wherein said aperture is of a substantially constant horizontal dimension whereby said sheet member reflects and transmits light in a ratio which is substantially inversely proportional to liquid level over the predetermined range.

10. The device of claim 9 wherein said lens and said member are formed as a one-piece unit.

11. The device of claim 9 wherein said light collection station is shielded from said source whereby the amount of light collected by said station is substantially inversely proportional to liquid level over the predetermined range.

12. THe device of claim 9 wherein said light collection station is the end of a fiber optics conducting member.

13. The device of claim 12 wherein said source of light is the end of a fiber optics conducting member the other end of which is exposed to a light emitter.

14. The device of claim 13 wherein said light emitter is a solid state light emitter.

15. The device of claim 12 wherein said source of light is a solid state light emitter.

16. The device of claim 9 wherein said lens, said member, said source and said collection station are all formed in a single unit.

17. The device of claim 16 wherein said unit is totally encapsulated.

18. A device for visually indicating the level of liquid over a predetermined range in a remote container, said device comprising:

a sheet of light transmitting material forming a substantially vertical window into said container and extending vertically over the predetermined range, said sheet being of a colored material which colors and reflects exterior light if exposed to gas at its interior surface and transmits exterior light if exposed to liquid at its interior surface;

a source of substantially uncolored light exterior of said container at least a portion of which shines upon said sheet;

a light collecting station exterior of said container for collecting light reflected by the exterior surface of said sheet, said light collection station also exposed to a portion of said substantially uncolored light and thus collecting substantially uncolored light when said liquid is at or above the maximum liquid level of the predetermined range and collecting increasingly colored light as said liquid level decreases to the minimum level of the predetermined range; and

a lens mounted exteriorly of said container for directing substantially all of said reflected colored light to said light collection station.

19. A device for monitoring the liquid level over a given range, in two side-by-side containers, said device comprising:

a housing adapted for sealing engagement with said containers, said housing having two hollow projections each of which sealingly engage an aperture in the side wall of each container, said apertures extending vertically over the given range;

sheets of light transmitting material mounted in said projections, said sheets forming windows into said containers and extending over said given range, said sheets of a material which will reflect light shining on one surface if its opposite surface is exposed to gas and will transmit light shining on one surface if its opposite surface is exposed to liquid;

a single source of light mounted in said housing for providing light rays which shine upon both of said sheets;

a pair of light collecting stations, one for each sheet, receiving the light reflected by its corresponding sheet; and

a pair of lens, each one integral with a sheet of light transmitting material and respective light collection station for directing substantially all of the light reflected by a aheet to its respective light collections station.

20. The device of claim 19 wherein said light collection stations comprise ends of separate fiber optics conducting members.