Drop Counter And Flow Meter For Apparatus And Method For Determining The Thermal Stability Of Fluids

• US 20120014405A1
• Filed: 08/04/2010
• Published: 01/19/2012
• Est. Priority Date: 07/16/2010
• Status: Active Grant

• Current Assignee: Petroleum Analyzer Company LP (Roper Technologies, Inc.)
• Original Assignee: Petroleum Analyzer Company LP (Roper Technologies, Inc.)
• Inventors: Anderson, David G., Youngblood, Larry M., Yang, Guoxing, Spino, Larry A., Berkhous, Scott K., Fang, Fang
• Granted Patent: US 8,277,118 B2
• Time in Patent Office: Days
• US Class Current: 374/43
• CPC Class Codes: G01N 33/2805 investigating the resistance to heat or oxidation to the weather, to corrosion, or to light G01N17/00

Abstract

A thermal oxidation tester is shown for determining thermal stability of a fluid, particularly hydrocarbons when subjected to elevated temperatures. The tendency of the heated fluid to oxidize and (1) form deposits on a surface of a heater tube and (2) form solids therein, are both measured at a given flow rate, temperature and time. The measured results are used to determine whether a fluid sample passes or fails the test. Sample flow rate is important in the jet fuel thermal oxidation test. Current practice requires manual drop counting or flow confirmation with the use of volumetric glassware. An apparatus is described to precisely measure the flow rate and automatically perform flow rate check using a drip rate method and/or volumetric method.

Claims

1. An apparatus for testing thermal oxidation stability of a test sample such as a hydrocarbon fuel comprising:

a source of electric power;

a heater tube connected to said source of electric power for flowing current to heat a center section of said heater tube to a predetermined temperature;

a coolant flow circuit supplying coolant to each end of said heater tube to keep each end thereof near room temperature;

an aeration circuit with an aeration pump for pumping air to aerate said test simple in a sample container;

a test sample flow circuit for flowing said test sample around said center section to heat said test sample to said predetermined temperature, said test sample flow circuit including;

sample drive pump pumping said test sample from said sample container around said center section of said heater tube;

a differential pressure filter in said test sample flow circuit after said heater tube to filter out any solids that may have formed in said test sample when heated to said predetermined temperature due to oxidation of said test sample;

a differential pressure sensor for measuring differential pressure across said differential pressure filter;

a back pressure regulator for maintaining said test sample being pumped by said sample drive pump at a test pressure high enough to keep said test sample in liquid phase when heated to said predetermined temperature;

a waste container for collecting such hydrocarbon fuel after said test;

a sample flow meter connected to said test sample flow circuit for accurately measuring said test sample flowing there through.

2. The apparatus for testing thermal oxidation stability of said test sample as recited in claim 1 wherein said sample flow meter includes measuring fill time for said test sample to fill a flow rate measuring container from a first level to a second level.

3. The apparatus for testing thermal oxidation stability of said test sample as recited in claim 2 wherein said flow meter further comprises a given volume in said flow rate measuring container between said first level and said second level, a computer for calculating a flow rate by using said given volume and said fill time.

4. The apparatus for testing thermal oxidation stability of a test sample as recited in claim 3 wherein said flow meter includes a drop counter to measure drip time for said test sample, said drip time being used to calculate flow rate in said computer.

5. The apparatus for testing thermal oxidation stability of said test sample as recited in claim 4 wherein said drop counter counts drops of said test sample received with a photo detector.

6. The apparatus for testing thermal oxidation stability of said test sample as recited in claim 5 wherein said flow meter has photo detectors for determining when said test sample in said flow rate measuring container reaches said first level and said second level

7. The apparatus for testing thermal oxidation stability of said test sample as recited in claim 4 wherein the said drop counter and flow meter further comprises a deflector for directing said drops against inside walls of said flow rate measuring container.

8. The apparatus for testing thermal oxidation stability of said test sample as recited in claim 4 wherein said drop counter and flow meter has a vent for said flow rate measuring container to allow air to escape or enter said flow rate measuring container and a valve to drain said test sample from said flow rate measuring container.

9. The apparatus for testing thermal oxidation stability of said test sample as recited in claim 7 wherein said drop counter and flow meter has visual indicators when said test sample reaches said first level and said second level.

10. A method of testing a test sample in liquid form for thermal oxidation stability comprising the following steps:

aerating said test sample in a sample container with dry air to saturate said test sample with oxygen;

heating a center section of a heater tube to a predetermined temperature by flowing current there through;

cooling each end of said heater tube by flowing coolant from a coolant flow circuit to said each end;

pumping said test sample at a low flow rate around said center section of said heater tube so that temperature of said test sample is raised to approximately said predetermined temperature;

test filtering with a differential pressure filter said test sample to collect solids formed in said test sample when heated to said predetermined temperature;

maintaining an elevated pressure on said test sample during said pumping step sufficient to keep said test sample from evaporating;

discharging said test sample through a drop counter and flow meter to a waste container.

11. The method of testing the test sample in liquid form for thermal oxidation stability as recited in claim 10 wherein said flow meter has a flow rate measuring container with a given volume between level zero and level one, photo detectors in said flow rate measuring container to detect when said test sample reaches level zero and thereafter level one.

12. The method of testing the test sample in liquid form for thermal oxidation stability as recited in claim 11 includes a further step of calculating flow rate by using said given volume and fill time for said test sample to accumulate from said level zero to said level one.

13. The method of testing the test sample in liquid form for thermal oxidation stability as recited in claim 10 includes an additional step of counting drops and measuring drip time of said test sample entering said flow rate measuring container and using drip time of a predetermined number of drops counted to provide an automated drip rate method for a flow rate check.

14. The method of testing the test sample in liquid form for thermal oxidation stability as recited in claim 11 includes an initial step of closing a valve from said flow rate measuring container and after said test sample reaches said level one, opening said valve.

15. The method of testing the test sample in liquid form for thermal oxidation stability as recited in claim 10 includes venting said flow rate measuring container for air and/or test sample overflow.

16. The method of testing the test sample in liquid form for thermal oxidation stability as recited in claim 11 wherein said photo detectors are infrared LEDs and corresponding photodiodes.

17. The method of testing the test sample in liquid form for thermal oxidation stability as recited in claim 13 includes deflecting said drops to an inside wall of said flow rate measuring container before said second level.

18. A drop counter and flow meter for use in testing thermal oxidation of a test sample under ASTM D3241 Standard, said drop counter and flow meter comprising:

a container;

a test sample input near the top of said container;

a valve for closing an output near the bottom of said container;

a first level detector on said container to determine when said test sample reaches a first level in said container;

a second level detector on said container to determine when said test sample reaches a second level in said container;

a computer connected to said first level detector and said second detector for calculating flow rate from (a) lapsed time and (b) volume of said container between said first level and said second level.

19. The drop counter and flow meter for use in testing thermal oxidation of a test sample under ASTM D3241 Standard as recited in claim 18 wherein said computer sends a valve signal to said valve to open said valve when said second level is reached in said container.

20. The drop counter and flow meter for use in testing thermal oxidation of a test sample under ASTM D3241 Standard as recited in claim 19 wherein said container has a vent near said top thereof to allow air in or out of said container as said container is emptying or filling, respectively.

21. The drop counter and flow meter for use in testing thermal oxidation of a test sample under ASTM D3241 Standard as recited in claim 20 further including a deflector between said test sample input and said second level detector, said deflector causing drops of said test sample to flow down inside walls of said container.

22. The drop counter and flow meter for use in testing thermal oxidation of a test sample under ASTM D3241 Standard as recited in claim 21 further includes a drop detector for detecting said drops of said test sample entering said container and a counter connected to said drop detector for counting said drops, said counter being connected to said computer for measuring drip time of a predetermined number of drops of said test sample flowing into said container.

23. The drop counter and flow meter for use in testing thermal oxidation of a test sample under ASTM D3241 Standard as recited in claim 22 wherein said drop detector, said first level detector and said second level detector are pairs of infrared LEDs and photodiodes.

24. The drop counter and flow meter for use in testing thermal oxidation of a test sample under ASTM D3241 Standard as recited in claim 23 wherein said drop counter and flow meter has visual indicators to show when one or more of the following has occurred:

said first level is reached by said test sample;

said second level is reached by said test sample;

said drops are received in said container;

said valve is open; and

/or

power to said drop counter and flow meter is ON.