Environmental media and pressure sensor

• US 6,005,242 A
• Filed: 08/15/1997
• Issued: 12/21/1999
• Est. Priority Date: 08/15/1997
• Status: Expired due to Term

• Current Assignee: Alconi Sensline
• Original Assignee: Alconi Sensline
• Inventors: Chernyak, Alex H.
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): Luu, Thanh X.
• Application Number:
  US08/911,959
• Time in Patent Office: 858 Days
• Field of Search: 250/227.14, 250/577, 250/574, 250/231.19, 73/705, 73/714
• US Class Current: 250/227.14
• CPC Class Codes: A61B 5/02154 by optical transmission
• CPC Class Codes: G01L 11/025 using a pressure-sensitive optical fibre

Abstract

A sensor for detecting environmental media and pressure comprises two types of optical fibers. An intrinsic fiber containing a portion of the fiber with the jacket removed is sensitive to its surroundings as some light traveling through the fiber will escape. The change in light intensity is received by a light detector, and this information is interpreted to correspond to a certain media, a change in media, or a phase change in media. An extrinsic fiber with a membrane and mirror located at one end is placed vertically in the media. Pressure from the media changes the position of the membrane and the mirror, resulting in a change in the intensity of the light reflected back through the fiber to the light detector. The pressure can then be used to determine the volume of the media in the container. Pressure determination can be continuous. In addition, both types of sensors can be networked, allowing information from one sensor to influence the gathering of information from the other. Both sensors are housed in a durable container, which is connected to the light source and light detector. The container has protective grooves with concave shapes, which prevents accidental damage to the fragile fibers.

Claims

1. A method for identifying a medium in a mixture of media and determining a level of said mixture of media by using a detector having a light source for providing a light and a light detector for receiving said light, said method comprising the following steps:

a) providing a first light path for said light between said light source and said light detector through a first optical fiber;

b) providing a media sensor in said first optical fiber for continuously monitoring medium identity through contact inducing a first change in the intensity of said light;

c) providing a second light path for said light between said light source and said light detector through a second optical fiber;

d) providing a pressure sensor for continuously monitoring pressure through contact inducing a second change in the intensity of said light;

e) mounting said media sensor and said pressure sensor in a housing and lowering said housing into said mixture of media such that said pressure sensor and said media sensor continuously monitor at the same sensing depth;

f) identifying media interfaces using said pressure sensor; and

g) providing a means for networking information from said media sensor and said pressure sensor for determining the level of said mixture of media.

2. The method of claim 1, wherein said step of identifying media interfaces comprises identifying a step-wise pressure change.

3. The method of claim 1, wherein said means for networking information verifies a change of media by comparing a pressure reading from said pressure sensor with a medium identity reading from said media identity sensor.

4. The method of claim 3, wherein said comparing step is performed when said networking means receives a step-wise pressure change reading from said pressure sensor.

5. The method of claim 3, wherein said comparing step is performed when said networking means receives a media identity change reading from said media identity sensor.

6. The method of claim 1, wherein said mounting step comprises mounting said media identity sensor in a first recess and mounting said pressure sensor in a second recess.

7. The method of claim 6, wherein said first recess and said second recess are provided at the same height.

8. The method of claim 6, wherein said first recess and said second recess are arcuate.

9. The method of claim 1, wherein said contact between said media mixture and said pressure sensor produces a deformation of said pressure sensor which causes said second change in the intensity of said light.

10. The method of claim 1, wherein said contact between said media mixture and said media identity sensor produces a leakage of said light which causes said first change in the intensity of said light.