Guest Posted February 8, 2020 Report Posted February 8, 2020 Many times there are discussions concerning Floscan transducers. Today I decided to take an old one apart for a look inside. The first picture is with the bottom cut open and the cap pried out, you can see the paddle wheel inside the body. The second picture is the paddle wheel and it’s very sharp axle on which it spins. On the back side are tiny paddles driven by the fuel. The third is the cap with the bearing and I’m guessing light reflector? The forth picture is with a piece of wire forced through the inlet side at the bottom of the picture, tracing the flow of fuel. Fuel enters and spins the paddle wheel spiralling downward exiting the port at the top of the picture. At about the 11 o’clock position is the sensor which I assume counts the pulses. Clarence Quote
Pritch Posted February 9, 2020 Report Posted February 9, 2020 I don't think you drink, but when you do, you always drink the good stuff Pritch PS Keep it up you always have something good to say Quote
Andy95W Posted February 9, 2020 Report Posted February 9, 2020 That would clean up nicely with some WD-40 and compressed air to blow it out. 1 Quote
carusoam Posted February 9, 2020 Report Posted February 9, 2020 Awesome details, Doc! 1) Proof that the sensor actually is light based, not magnetic... 2) The wings on the paddle wheel are shades, large enough to block the light... each time. 3) Great visualization technique showing how the fuel flows through the sensor device.... 4) The pointy part of the spindle is the reason there is a ‘this side up’ note in the installation instructions... 5) There is a flow channel to handle a jammed paddle wheel.... Thanks for the effort to bring these details to light! PP thoughts only, not a sensor guy... Best regards, -a- Quote
Guest Posted February 9, 2020 Report Posted February 9, 2020 They’re an amazing design, with a K factor of 30K per gallon that little wheel spins about 5000 times per gallon for thousands of trouble free hours. Clarence Quote
PT20J Posted February 9, 2020 Report Posted February 9, 2020 22 minutes ago, carusoam said: Awesome details, Doc! 1) Proof that the sensor actually is light based, not magnetic... 2) The wings on the paddle wheel are shades, large enough to block the light... each time. 3) Great visualization technique showing how the fuel flows through the sensor device.... 4) The pointy part of the spindle is the reason there is a ‘this side up’ note in the installation instructions... 5) There is a flow channel to handle a jammed paddle wheel.... Thanks for the effort to bring these details to light! PP thoughts only, not a sensor guy... Best regards, -a- Actually, I believe both ends of the wheel axel are pointed. It just doesn’t show well in the photo. According to JPI, vapor in the fuel lines affects accuracy. The transducer is designed so that when mounted with the wires up, the inlet is lower than the outlet which forces vapor to the top of the unit where a vent allows it to escape. A JPI tech support person told me it really doesn’t make any difference in most installations. The Mooney factory installation on the J mounts it upside down. In an attempt to improve accuracy, I remounted it right side up. It made no difference whatsoever. Skip 1 Quote
PT20J Posted February 9, 2020 Report Posted February 9, 2020 12 minutes ago, M20Doc said: They’re an amazing design, with a K factor of 30K per gallon that little wheel spins about 5000 times per gallon for thousands of trouble free hours. Clarence The Floscan website list the bearing life expectancy at 10,000 hrs. Min. A tech at Shadin or JPI (can’t remember which) told me that they tend to flake out after 20 years in service however. Skip Quote
jetdriven Posted February 9, 2020 Report Posted February 9, 2020 I think the wires to it break at the case long before that happens Quote
Guest Posted February 9, 2020 Report Posted February 9, 2020 6 hours ago, PT20J said: Actually, I believe both ends of the wheel axel are pointed. It just doesn’t show well in the photo. According to JPI, vapor in the fuel lines affects accuracy. The transducer is designed so that when mounted with the wires up, the inlet is lower than the outlet which forces vapor to the top of the unit where a vent allows it to escape. A JPI tech support person told me it really doesn’t make any difference in most installations. The Mooney factory installation on the J mounts it upside down. In an attempt to improve accuracy, I remounted it right side up. It made no difference whatsoever. Skip You are correct, both ends of the paddle wheel axle are pointed and sit in two small bearings, one in the body and one in the cap. Clarence Quote
carusoam Posted February 9, 2020 Report Posted February 9, 2020 Another issue MSers have reported in the past, regarding flaky readings from the FF sensor... Air bubbles getting drawn in from places upstream such as a worn fuel selector valve... So... if you get higher FF readings than usual, all of a sudden... look for blue stains in various places... When air leaks in during operations, fuel leaks out when things are not running... Fuzzy PP memories, not fuzzy mechanic memories... Best regards, -a- Quote
EricJ Posted February 9, 2020 Report Posted February 9, 2020 12 hours ago, carusoam said: Awesome details, Doc! 1) Proof that the sensor actually is light based, not magnetic... I'm surprised by that. Sensors like this are often non-contact Hall-effect sensors with small magnets in the rotor. That allows the unit to be completely sealed, where this one has an opening for the optical sensor. One downside of an optical sensor is that debris/bubbles/crap can interfere with the sensing and affect accuracy. These seem to work well enough, though, so there ya go. 1 Quote
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