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OT fuel oil flow count/flow measurement

mjk

Titanium
Joined
Oct 20, 2005
Location
Wilmington DE USA
Shop heater is oil fired boiler
I have an hour meter on the burner, but I would like to verify oil consumption other than sticking the tank/looking at the float gauge on top of the tank. Burner rate is 0.5 gal/hour
most of the meters I've found are for higher flow rates or $$$$$

I would be placing in the oil feed line from the tank not the pressure line to the nozzle
No return lone to deal with

Suggestions?

Mike
 
you could try and diy your own flow meter by using four resistors, doesn't matter if they are negative temp co or positive temp co resistors, but they need to have significant temperature coefficients that are linear. you can use four, 100 ohm platinum rtd's (they make fake platinum rtds for a few bucks or less each)


buy a digital scale. doesn't matter if its 100 grams or 100 kilograms capacity. they all use a strain gauge which has about a 2% resistance change at full load.

epoxy the four RTD resistors to the copper line you want to measure the flow rate of, in pairs, about 3 inches apart.

wire up the digital scale as if those 4 resistors were a strain gauge, in a bridge configuration.


with no oil flowing, use a pushbutton switch to short the mid point of the bridge together and turn the scale on. the scale will read zero grams. open the switch and you'll see some offset.

tweak the value of one of the resistors by adding some resistance in series with it, until the scale reads zero when you short out the bridge and turn the scale on.


now what you do is add a resistor in between those 2 pairs of resistors, and you send some current through it. maybe half a watt worth of heat. maybe it takes 1 watt of heat. epoxy say, a 10K resistor and .5 amp fuse and run it from a 120v line.

the oil flowing will cool off the first resistor and heat up the second resistor.

flow rate is proportional to the digital scale readout.

(because they all auto turn off, you'll have to press the button to short out the bridge, turn the scale on, then release the switch and the displayed value will be the oil flow rate)

to get better accuracy you will need to ensure the heater has a constant current or a constant voltage through it. you could use a cell phone charger to send 5 volts through a 25 ohm resistor, should be 1% or so accurate across normal temperature changes.
 
Can send the oil through a CFM flow meter for argon or nitrogen. the ones with a 1/8" diameter plastic ball in a tapered plastic tube.

tilt the flow meter at an angle if it doesn't work right. replace the plastic ball with a metal one heavier than the oil....
 
Just hook a gallon pail to a temporary supply line. See how long it runs on a quart. 15 min or so would be a good starting guess ;-).

Not rocket science.
 
A half gallon/hour? Thats a pretty small heater. Weighing your fuel tank will be the cheapest option. For a true meter, look up Rotameter. I don't know if you can find one with that small of range. That will require a very small orifice.
 
Just to clarify , the supply tank is 275 gallons and it is anchored to the concrete slab(outside)
I'll try Rotameter.
The 0.5 gal/hr is the min size nozzle that can be run in the burner with 1.5 being the max, so I want to make sure the 0.5 is addressed.
with the hour meter and past history I can guesstimate when the tank will need a refill.
Just looking for that solution that will be accurate and safe.
 
Just to clarify , the supply tank is 275 gallons and it is anchored to the concrete slab(outside)
I'll try Rotameter.
The 0.5 gal/hr is the min size nozzle that can be run in the burner with 1.5 being the max, so I want to make sure the 0.5 is addressed.
with the hour meter and past history I can guesstimate when the tank will need a refill.
Just looking for that solution that will be accurate and safe.

How about a float switch and indicator light?
 
Adding to what CalG said, get or make container with relatively small diameter. If you run the burner for about a half hour you can calculate the consumption probably more accurately than any flow meter you rig up.
 
Really

I have never seen a gun type burner that couldn't be re plumbed with a length of fuel hose, a pair of barb fittings and a coffee can.

Why make it hard? It will not be any more accurate.
 
Fuel oil suppliers use degree day method to know when to return to fill tank. It's based on how cold the weather is. They will make sure your don't run out without you having to do anything.
 
Fuel oil suppliers use degree day method to know when to return to fill tank. It's based on how cold the weather is. They will make sure your don't run out without you having to do anything.


For cris sake. there are other plans besides "auto fill", I'm on a "call when needed" plan for both oil and gas.

Go figure!
 
I also found almost all low flow meters useless. However there is one made in Germany for a reasonable price that I use to measure diesel flows of 2.5 gal/ hr for my cast iron foundry. I am confident it would also be reliable at lower flow rates. Rather than re write all the info here I will refer you to a thread I posted on thehomefoundry.org about it.

Here is a link to the meter: Durchflussmesser, Flowmeter, Ovalradzahler, mini, Chemie, Wasser, Glykol, Ol, Diesel, Schmierstoffe, AdBlue. They claim .01 to 10 L / min flow rate capability. I’d trust that.



Measuring Instantaneous and Total Fuel Flow with a Pelton Sensor and Digital Readout | The Home Foundry

Denis
 
you could try and diy your own flow meter by using four resistors, doesn't matter if they are negative temp co or positive temp co resistors, but they need to have significant temperature coefficients that are linear. you can use four, 100 ohm platinum rtd's (they make fake platinum rtds for a few bucks or less each)


buy a digital scale. doesn't matter if its 100 grams or 100 kilograms capacity. they all use a strain gauge which has about a 2% resistance change at full load.

epoxy the four RTD resistors to the copper line you want to measure the flow rate of, in pairs, about 3 inches apart.

wire up the digital scale as if those 4 resistors were a strain gauge, in a bridge configuration.


with no oil flowing, use a pushbutton switch to short the mid point of the bridge together and turn the scale on. the scale will read zero grams. open the switch and you'll see some offset.

tweak the value of one of the resistors by adding some resistance in series with it, until the scale reads zero when you short out the bridge and turn the scale on.


now what you do is add a resistor in between those 2 pairs of resistors, and you send some current through it. maybe half a watt worth of heat. maybe it takes 1 watt of heat. epoxy say, a 10K resistor and .5 amp fuse and run it from a 120v line.

the oil flowing will cool off the first resistor and heat up the second resistor.

flow rate is proportional to the digital scale readout.

(because they all auto turn off, you'll have to press the button to short out the bridge, turn the scale on, then release the switch and the displayed value will be the oil flow rate)

to get better accuracy you will need to ensure the heater has a constant current or a constant voltage through it. you could use a cell phone charger to send 5 volts through a 25 ohm resistor, should be 1% or so accurate across normal temperature changes.

trying to understand: why will the oil "cool off the first resistor and heat up the second resistor"?
 
The flow rate of the installed nozzle and an hour meter will be plenty accurate for determining when to order a fuel oil delivery. You certainly should not be trying to run the tank to near empty before ordering. Order at about 112 hours of burner run time and be done with it. If you want an actual tank reading you can add a magnet to the indicator on the float gauge and a simple reed switch positioned appropriately to turn on a remote indicator light when the tank is down 20% full.
 
Years ago we had an automotive aftermarket cruise control that had a flow sensor you added to the fuel line and it measured flow and gave you instant MPG.

maybe creativ Amazon searches may find something, they have boat loads of measurement devices.

One also could simply add a pressure sensor to a fitting if present at or near bottom of tank.

Deeper fuel will be higher weight or pressure, when it gets below some point pressure decreases and a closure can signal something.

Many types of pressure sensors, we found many while looking for some 4-20 ma units.

Sent from my SM-G781V using Tapatalk
 
The flow rate of the installed nozzle and an hour meter will be plenty accurate for determining when to order a fuel oil delivery. You certainly should not be trying to run the tank to near empty before ordering. Order at about 112 hours of burner run time and be done with it. If you want an actual tank reading you can add a magnet to the indicator on the float gauge and a simple reed switch positioned appropriately to turn on a remote indicator light when the tank is down 20% full.

Actually fluel flow rates through nozzles is very sensitive to changing ambient conditions. I am running a Hago siphon nozzle made for a commercial boiler system which is sensitive to fuel pressure (is the tank head height 4 feet full or4” near empty?), as well as compressed air pressure since the nozzle siphons due to the compressed air stream. Finally combustion air velocity and pressure also affect flow rates. I have worked out ways to keep those factors nearly constant. But flow rates even in a simple drip burner setup will depend on head pressure which will vary depending on tank fullness. The meter system I linked shows both instantaneous flow rate and total volume metered to that point and can also turn off flow after a certain time or volume total.

Denis
 
Thank you Denis, an option I'll consider.

I installed the hour meter to give me that approximate usage soon after moving into the building a few years ago. The previous owner had botched the boiler feed and return lines causing the boiler to run 10x before the building was warm. I was curious how much run time the boiler had after fixing the screwups. The shops thermostat is programable, weekends and night set to drop to 45 deg, and on 1 hour before start time and its enough time to bring the shops to 60 degrees.
I'd like to be able to document actual daily usage vs daily actual temp. The total usage from last fill would just be an added benefit of not having to stick the tank
Without trying to offend anyone, I don't want to install a gadget to accomplish the next step, but I don't want to spend $1200 like the quote I received for a "precision low volume flow meter"
Watching the float gauge and confirming with a "stick" has prevented me from running out in the past.
To put it in perspective I just want to go from a tape measure to a digital readout but I don't need a CMM
 








 
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