drewdin

Hi Guys,

I want a digital oil tank level meter, currently I have a standard glass bulb that has lines on it listed as full and empty. The tank is a 275 gallon tank.

Does anyone have any suggestions on a brand, type or suggestion? Thanks

Wuzzat?

http://forum.allaboutcircuits.com/showthread.php?t=35057

I guess you could sense pressure at the base of the tank, use ultrasonics to detect the level below the top of the tank, or use a ~1000 lb load cell under one end of the tank. There might also be capacitive sensors.

An all-home-built device might be $50 or more. Higher accuracy = higher cost.

Maybe you just want a low oil level alarm?

nealtw

http://heatbits.com/installation-equipment/oil-tank-equipment/unitop-remote-readout-oil-tank-level-gauge.html

drewdin

I don't mid the price, i just want it easier to use than having to going the basement.

@wuzzat, I am trying to do the same thing as that post!

Thanks Guys

Wuzzat?

Some hifi stuff has linear potentiometers for volume controls, etc. These may be had for $10. Let's say the wiper travel is 2"

Then you need a two strong springs (e.g., disc springs from Grainger) and lever system out of wood/metal such that a full/empty tank gives you 2" of travel on the end of the lever. 275 gals of #2 fuel oil might weigh 2000# and the tank weight needs to be subtracted out, mentally or electronically.

Then for $20 in parts (excluding case) you get an analog or digital meter and a REF05 or equivalent bandgap voltage reference and a 9v battery or DC wall wart from Hosfelt or Allelectronics or Digi-key. You run wires upstairs such that the circuit is only powered when you want a reading.

I got a lot of free parts by putting a free ad in the company newspaper that said "Wanted: VCR/edger/TV/answering machine/exercise machine/tools that you consider not worth fixing."

drewdin

I got a little horner PLC and an ethernet jack in the room. I plan on making a webpage/database that is going to store a reading every hour or two and send me an email when the tank gets to 1/4 and 1/8 of a tank.

I found a local oil company that sells something similiar but its limited and ugly, its called a B rocket. They wanted $179 for it and $100 for install. Its just a 2"npt fitting that screws in place of the existing meter. thanks god im handy...

Wuzzat?

Yes.

A new inducer motor PC board for my furnace containing a relay & four diodes is $220. For $11 including shipping I got an Omron relay to fix the board, a 20:1 price ratio.
I find out I have to add an RC filter to run the relay but I have junkbox parts that can do this.

People have occasionally gotten Grainger motors for $50 that replaced $400 air handler motors.

BTW, the sides of a full oil tank may bulge out 1/16" more than for an empty tank. This is about the amount of travel for the actuators of some Microswitches so a rigidly mounted switch next to the tank wall may tell you when you're near empty.

http://www.hosfelt.com/contents/en-us/d163.html

drewdin

Thanks, I am looking into an ultrasonic sensor that will mount in place of the current display and output either rs-485, vdc or 4-20mA. I guess it works like a proximity probe, its full board when empty (Empty tank = 20mA, etc...). Seems like it would be the easiest was to do it depending on how much the sensors cost. I'm still looking around for one

Wuzzat?

If your tank has a cross section other than rectangular then knowing the interior level will not tell you the volume remaining.
You could program in mensuration formulas to do the conversion.

nealtw

Many years ago I visited a house with a friend and there was a light on over the basement door that didn't seem to belong. When I asked what it was for, the answer was (it tells to order oil). After a few calls and getting in touch with people I haven't seen for years I findly got some answers. This guy was a bit of an inventor and his first try was to mount the tank on wheel barrow wheels on one end and check tire pressure to determin tank level. The second try was to use two peices of 2x6 on the flat under the two legs on one end with automotive valve spring between them. The springs would compress under full tank and expand as the oil would be used. He then mounted a toggle switch that would record the movement past a certain spot and the light would come on.