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Testing Thermistors as Liquid Level Sensors. Kristy Lubinski. Circuit Diagram #1. V. PT 1000. PT 1000. 750 Ω. 5 V. Circuit Diagram #2. V. PT 1000. PT 1000. 750 Ω. 5 V. Set-Up. PT 1000’s. 1 mm space. Boil Off Test. Place PT 1000’s just into liquid
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Testing Thermistors as Liquid Level Sensors Kristy Lubinski
Circuit Diagram #1 V PT 1000 PT 1000 750 Ω 5 V
Circuit Diagram #2 V PT 1000 PT 1000 750 Ω 5 V
Set-Up PT 1000’s 1 mm space
Boil Off Test • Place PT 1000’s just into liquid • Collect data while the liquid boils off • Boil off rate measured separately • Liquid Nitrogen • 0.2 mm/min • Liquid Argon • 0.2 mm/min
Circuit #2 – Liquid Argon Trial 1 Both In One In Both Out
Circuit #2 – Liquid Argon Trial 2 Both In One In Both Out
Time Resolution Test • Quickly place both PT 1000’s in liquid at 1:30 • Quickly pull both PT 1000’s out of liquid at 2:30 • Measure response time
Circuit #1 – Liquid Nitrogen Both In Both Out Both Out
Circuit #2 – Liquid Nitrogen Both In Both Out Both Out
Circuit #2 – Liquid Argon Both In Both Out Both Out
Two Jump Test • Lower PT 1000’s into liquid • Using only LabView Interface, stop apparatus when 1 PT 1000 is in liquid • Repeat lifting out of liquid • Verify location of PT 1000 visually
Circuit #1 – Liquid Nitrogen Both In One In One In Both Out Both Out
Circuit #2 – Liquid Nitrogen Both In One In One In Both Out Both Out
Circuit #2 Liquid Argon Both In One In One In Both Out Both Out
Level Test • Three sets of PT 1000’s on outside of plexiglass cylinder ring • Level using three strings that suspend the ring above liquid (like a puppet) Blue string used to hold ring up PT 1000’s
Attempt to Level Resistors and then Boil off LN2 5. Boil off points were different for all 3 sets, design set-up was not ideal, resistors were not all exactly 1 mm apart, not exactly on same location around the ring 3. Wiggled all three cords to see if they responded 2. All three resistors around same level 4. Re-leveled all three and let sit to boil off liquid 1. Trying to level ring by pulling on individual strings until one resistor was in the liquid and one was out of the liquid ~3.7 V