Fuel tank sensor question
wolff
Posts: 43
I have a fuel tank (diesel) that uses a dipstick about 1/4 inch in diameter. I would like to make something that the stamp could read that would fit into the dipstick hole to tell me when the tank is full. It does not have to be terribly accurate. I just need to know when the level·is with in an inch or two from the top.
Any ideas???
Thanks,
J
Any ideas???
Thanks,
J
Comments
Put an IR detector and reciever two inches from the top of the tank, each on opposite sides of the tank. Have the stamp send the LED the harmonic, and the phototransiter will receive it, and tell the stamp. But when the diesel comes up to that level, the connection will be broken, and the stamp will know.
-Also consider the fact that diesel is highly explosive, and one spark can mean poof
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Thats an easy one, use a 1/4 tube, open at bottom and close to the top of tube that allows float movement, put a pin across bottom to hold float, the float would either trip
a switch, or break an ird dectector pair, or if a little magnet was placed in top of float , it would trip a hall sensor... I have seen many
rare-earth magnets that would easily work, and the are very powerful!! I have several that I scrounged from old scsi hard drives...
about 3/16 diameter, and 5/32 in length, they are very powerfull! You can take it from there.
Bob N9LVU
Post Edited (Robert Kubichek) : 5/7/2006 5:00:05 PM GMT
http://forums.parallax.com/showthread.php?p=582014
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I like the float/magnet/hall effect idea best.
Thanks to al!
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I did a lot of experimenting with the Q prox IC's (that I do believe parallax can provide) some time back for water level detection. Whilst they worked very well, they failed in range of temperatures required.
If it where me, I would probably be looking real hard at the pressure switch, for it's known reliability and cheap price.
The problems assosiated with using any voltage inside a fuel tank are probably more to do with your insurance companies' attitude than risk of detonation and colorful destruction.
bongo
The only potential problem I can see is the fact that diesel is very oily, and a layer of diesel will remain in contact with the probes very after the level has dropped. But the resistance should still be much higher than if the probes when in diesel fuel.
This application will be used on my sailboat. Right now fueling requires two people. One to continually dip the tank while the other adds fuel (from the deck fueling port.) I would like to set it up so I could·remove (unscrew and pull out) the dipstick and screw in my contraption... which will have a LOUD audible alarm to tell me when to stop adding fuel. Then·I·can remove the contraption and replace the dipstick... And move on to the next tank!·
I'm not worried about insurance or fire. Low voltage and good engineering will mitigate the fire/explosion hazard.·
Any further ideas would be greatly appreciated!
Sincerely,
J
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As a further note, if the float was made right, there would not be ANY wires inside the tank.
It would be very easy if it was a straight line/shot into the fuel tank.
Bob N9LVU
I would use aquarium tubing, as it comes in several different sizes, is rigid, and clear, and cheap!
The smaller diameter sealed on the bottom would make a good float.
It could be as long as needed to provide floatation, it should clear the tank so electronics are not inside.
I would measure diameter of dipstick opening, and have the outer tube to be slightly smaller, with a smaller float tube that freely slides inside.
The longer the inside tube, the more the flotation, also the whole assembly can be as long as the tubes you get..
Bob N9LVU
·· Won't the fuel break down the aquarium tubing?· It seems I did a test using this tubing for fuel line although I could be wrong.· It was many years ago.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Hmm
Also I have seen teflon tubing used in labs that would work fine, but it is not translucent, and the cost is much higher!
Matter of fact, it would be better, as it would not be affected by the fuel at all nor change the magnetic field...
And you CAN solder it with the right past/solder combo ( I've done it to repair ham antennas)!
I have some aluminum tubes that make great blowguns, and are about 1/4" diameter....
Bob N9LVU
the switch can directly drive an audible or you can add it to your machinery alarm system if you have one. or you could make your own with a stamp.
http://www.fwmurphy.co.uk/products/fluid_level/fluid_l150_el150k1_el150ex.htm
http://www.pps-bv.nl/gb_frame_levelswitches.htm
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engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]
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Our riding lawnmower (john deere) has a little contraption on it's fuel cap cover. It's a foam block that is in a cage. When you put the cap and assembly on, the foam floats to some degree and causes a mechanical deflection on the top of the cap (where it indicates how much gas is in teh tank).
All you need to do is get a little bobber in a similar-like cage. set it in your tank in such a way that the ingoing fuel doesn't disrupt it (too much) and then put a little switch at the appropriate level in the 'cage' so that as the fuel rises, so does the bobber and then the switch will send an alarm.
Diesel isn't likely to go boom unless you have it under pressure and high temps....but I'd still go to some good effort to protect my wires/contacts to prevent any problems.
Just remember, we are all hobbiests here, your actions are your responsibility.
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Steve
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
I saw an idea a while back that would probably work for you. I don't remember where I saw it though. It used a reflective led-sensor combo connected so it was looking down a length of plexiglass or similar plastic rod. The opposite end of the rod was cut at a 45 deg. angle cleanly. The refraction index of rod to air was very different and the 45 deg. cut was like a mirror and the light bounced back. When the rod was immersed in a fluid, the 45 deg. angle looked clear and the light didn't bounce back. Therefore you have a detector with no moving parts and no sparking. Just make the rod the correct length for the level you want.
Credit goes to whoever dreamed this up before me.
Lee
·· Yeah, I knew there were some...Back in my R/C days I had to run the little rubber fuel lines from the tank to the engine...I don't know what that stuff was but it survived that fuel (which is not gasoline or diesel but...).
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Chris Savage
Parallax Tech Support
csavage@parallax.com
BTW, I like the plexi-rod reflection idea, quite ingenious.
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Post Edited (Paul Baker) : 5/9/2006 4:52:39 AM GMT
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Standard transducers go down to 2 psi ful scale which should be in the ball park.
Cheers
If the tank is vented, then you could probably use a 'weighing' transducer.
We actually have a rain gauge that works with the vibrating wire setup.
The wire is vibrating at, pick a number, say 1kHz (you can hear it)....as the bucket fills with rain water, it pulls on the wire and the string tightens which causes the frequency to go up. We then measure this frequency and determine how much went in the bucket.
Not sure if you could emerse a long vibrating string in to your fuel and use it like a guitar string....instead of your fingers holding the string for a given note, the fuel (at whichever level) would dampen the virbration enough to give you a note back.
We had a small vacuum deposition chamber in college (we made some small silicon wafer setups). Well, basically under a high vacuum we'd evaporate aluminum in a tungsten filament. The aluminum would then coat the wafer. Problem was, you kinda guessed at how thick the layer was with the time you left it in there (and the amount of aluminum too). Well, the prof took a crystal from his old tv and peeled part of the can back and stuck this in the deposition chamber. The idea then was to monitor the frequency of the crystal while the aluminum was depositing. For every Angstrom (I think that was the right word -- molecular level of aluminum deposited) of AL that ended up on the crystal, the frequency would drop by 1kHz (guessing). Was quite need....but there was a lot of runaway, so you had to pull the plug before you reached your thickness, and hope that it coasted to what you wanted.
(Sorry....was totally off topic!)
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Steve
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
When the tank was refilled from outside, the guy would pump in the oil until the second pipe stopped whistling.
I'm not sure exactly how the tank was designed - whether there was more than one air vent in the tank, or how the whistle pipe was attached. I imagine the whistling pipe entered the top of the tank and stuck a few inches below the top, so when the fuel reached it, air would stop leaving the whistling pipe, but there must have been some kind of allowance for accepting a few additional gallons.
Maybe something like that whistling pipe would work in your case. Sorry, this method doesn't require your Stamp.
David
To use a stamp, you could connect a little windvain to a microswitch (if the air is powerful enough coming out) and then have the stamp monitor the switch setting.
You could also take a tachometer and a propellor (not the new IC Parallax is selling [noparse];)[/noparse] ) and put it in the airflow area and monitor it's output voltage.
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Steve
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."