Apparatus for measuring oil oxidation using fluorescent light reflected from oil

• US 20050088646A1
• Filed: 04/30/2004
• Published: 04/28/2005
• Est. Priority Date: 10/28/2003
• Status: Active Grant

• Current Assignee: Korea Advanced Institute of Science and Technology
• Original Assignee: Korea Advanced Institute of Science and Technology
• Inventors: Kong, Hosung, Semenyuk, Mikhail, Yoon, Eui-Sung, Lyubov, Markova, Myshikin, Nickolai, Han, Hung-Gu
• Granted Patent: US 7,136,155 B2
• Time in Patent Office: Days
• US Class Current: 356/70
• CPC Class Codes: G01N 2021/6484 Optical fibres
• CPC Class Codes: G01N 21/643 non-biological material
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: G01N 33/2805 investigating the resistance to heat or oxidation to the weather, to corrosion, or to light G01N17/00

Abstract

An apparatus for measuring oil oxidation is capable of being mounted to mechanical devices for detecting power of fluorescent light reflected from oil in real time as an indication of the oil oxidation. A plurality of first optical fibers are connected to a light-emitting member for introducing the light into oil at different incidence points. A plurality of light-reflecting mirrors are immersed in the oil and disposed opposite to the incidence points. The light-reflecting mirrors are located at different distances from the incidence points. A plurality of second optical fibers are connected to the incidence points, respectively. A plurality of light-receiving members are connected to the second optical fibers for receiving the light and outputting the signals corresponding to the received light. A control portion calculates a fluorescence quantum yield and a light absorption coefficient of the oil based upon the signals from the light-receiving members and compares them with the reference values pre-stored in the control portion to determine the oil oxidation.

Claims

1. An apparatus for measuring oil oxidation, comprising:

a light-emitting means;

a plurality of first light-transmitting means, which extend from the light-emitting means, for introducing light into oil at a plurality of different incident points;

a plurality of light-reflecting means, which are immersed in the oil and disposed opposite the incident points, wherein each of the light-reflecting means is located at a different distance from the incident points;

a plurality of second light-transmitting means, which extend from the incident points;

a plurality of light-receiving means, which are connected to the second light-transmitting means, for receiving the light and generating signal outputs corresponding to the received light; and

a control portion, which calculates a fluorescence quantum yield and a light absorption coefficient of the oil, based upon the signals from the light-receiving means, and compares the calculated fluorescence quantum yield and light absorption coefficient with reference fluorescence quantum yields and light absorption coefficients pre-stored in the control portion to determine the oil oxidation.

2. The apparatus for measuring oil oxidation of claim 1, wherein the light-transmitting means is an optical fiber.

3. The apparatus for measuring oil oxidation of claim 1, wherein the apparatus further comprises a filtering means, which surrounds the light-reflecting means and the incident points, for preventing the light-reflecting means and the incident points from being damaged by pollutants in the oil.

4. An apparatus for measuring oil oxidation, comprising:

a light-emitting means;

a pair of first optical fibers, which extend from the light-emitting means, for introducing light into oil at two different incident points;

a light-reflecting mirror, which is immersed in the oil and disposed opposite one of the incident points and located at a predetermined light-passing distance from the incident point;

a pair of second optical fibers, which extend from the two incident points, respectively;

a first light-receiving means, which is connected to the second optical fiber extending from the incident point located opposite the light-reflecting mirror, for receiving the light and generating a signal output corresponding to the received light;

a second light-receiving means, which is connected to the other second optical fiber for receiving the light and generating a signal output corresponding to the received light; and

a control portion, which calculates a fluorescence quantum yield and a light absorption coefficient of the oil, based upon the signals from the first and second light-receiving means, and compares the calculated fluorescence quantum yield and light absorption coefficient with reference fluorescence quantum yields and light absorption coefficients pre-stored in the control portion to determine the oil oxidation.

5. The apparatus for measuring oil oxidation of claim 4, wherein the fluorescence quantum yield and the light absorption coefficient are calculated by the control portion from the following equations;

$\mathrm{\alpha <br><br>}<br><br>\left(\mathrm{\lambda <br><br>}\right)=\frac{U_2}{2<br><br>d_1<br><br>U_0}<br><br>\ln <br><br>\left(\frac{U_0-U_2}{U_1-U_2}\right)$ $\mathrm{\beta <br><br>}<br><br>\left(\mathrm{\lambda <br><br>}\right)<br><br>C_1=\frac{\ln <br><br>\left(\frac{U_0-U_2}{U_1-U_2}\right)}{2<br><br>d_1}$

where, α

(λ

) is the fluorescence quantum yield, d₁ is the light-passing distance, U_o is an output value of power of the light from light-emitting means, U₁ is an output value from the first light-receiving means, U₂ is an output value from the second light-receiving means, and β

(λ

)C₁ is the light absorption coefficient.

6. The apparatus for measuring oil oxidation of claim 4, wherein the apparatus further comprises a filtering means, which surrounds the light-reflecting mirror and the incident points, for protecting the light-reflecting mirror and the incident points from being damaged by pollutants in the oil.

7. An apparatus for measuring oil oxidation, comprising:

a light-emitting means;

a pair of first optical fibers, which extend from the light-emitting means, for introducing light into oil at two different incident points;

a first light-reflecting mirror and a second light-reflecting mirror, which are immersed in the oil and disposed opposite the two incident points, the first light-reflecting mirror and the second light-reflecting mirror being spaced apart from the two incidence points at different light-passing distances with respect to each other;

a pair of second optical fibers, which extend from the two incident points, respectively;

a first light-receiving means, which is connected to the second optical fiber extending from the incident point opposite to the first light-reflecting mirror, for receiving the light and generating a signal output corresponding to the received light;

a second light-receiving means, which is connected to the other second optical fiber extending from the incident point opposite to the second light-reflecting mirror, for receiving the light and generating a signal output corresponding to the received light; and

a control portion, which calculates a fluorescence quantum yield and a light absorption coefficient of the oil, based upon the signals from the first and second light-receiving means, and compares the calculated fluorescence quantum yield and light absorption coefficient with reference fluorescence quantum yields and light absorption coefficients pre-stored in the control portion to determine the oil oxidation.

8. The apparatus for measuring oil oxidation of claim 7, wherein the fluorescence quantum yield and the light absorption coefficient are calculated by the control portion from the following equations;

$U_1=\frac{\mathrm{\alpha <br><br>}<br><br>\left(\mathrm{\lambda <br><br>}\right)<br><br>U_0}{\mathrm{\beta <br><br>}<br><br>\left(\mathrm{\lambda <br><br>}\right)<br><br>C_1}<br><br>\left(1-{\mathrm{e<br><br>}}^{-2<br><br>\mathrm{\beta <br><br>}<br><br>\left(\mathrm{\lambda <br><br>}\right)<br><br>C_1<br><br>d_1}\right)+U_0<br><br>{\mathrm{e<br><br>}}^{-2<br><br>\mathrm{\beta <br><br>}<br><br>\left(\mathrm{\lambda <br><br>}\right)<br><br>C_1<br><br>d_1}$ $U_2=\frac{\mathrm{\alpha <br><br>}<br><br>\left(\mathrm{\lambda <br><br>}\right)<br><br>U_0}{\mathrm{\beta <br><br>}<br><br>\left(\mathrm{\lambda <br><br>}\right)<br><br>C_1}<br><br>\left(1-{\mathrm{e<br><br>}}^{-2<br><br>\mathrm{\beta <br><br>}<br><br>\left(\mathrm{\lambda <br><br>}\right)<br><br>C_1<br><br>d_2}\right)+U_0<br><br>{\mathrm{e<br><br>}}^{-2<br><br>\mathrm{\beta <br><br>}<br><br>\left(\mathrm{\lambda <br><br>}\right)<br><br>C_1<br><br>d_2}$

where, d₁ is the light-passing distance between the incidence point and the first light-reflecting mirror opposite thereto, d₂ is the light-passing distance between the incidence point and the second light-reflecting mirror opposite thereto, U₀ is an output value of power of the light from light-emitting means, U₁ is an output value from the first light-receiving means, U₂ is an output value from the second light-receiving means, α

(λ

) is the fluorescence quantum yield, and β

(λ

)C₁ is the light absorption coefficient.

9. The apparatus for measuring oil oxidation of claim 7, wherein the apparatus further comprises a filtering means, which surrounds the first light-reflecting mirror, the second light-reflecting mirror, and the incidence points, for protecting the first light-reflecting mirror, the second light-reflecting mirror, and the incidence points from being damaged by pollutants in the oil.