Digital Flow gauge required
Digital Flow gauge required
(OP)
I'm trying to find a digital flow gauge that will accurately measure (+/- 1%) a water flow of approx 100 ml/min. The water flows through 1/4 inch plastic pipe work and is low pressure, around 2 psi.
I've searched high and low and can't find anything suitable. Any suggestions would be greatfully appreciated.
I've searched high and low and can't find anything suitable. Any suggestions would be greatfully appreciated.





RE: Digital Flow gauge required
If you gave us some more information someone might be able to come up with a path to a solution (maybe a metering chamber?).
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. ùGalileo Galilei, Italian Physicist
RE: Digital Flow gauge required
RE: Digital Flow gauge required
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. ùGalileo Galilei, Italian Physicist
RE: Digital Flow gauge required
http://www.us.endress.com/en/Tailor-made-field-ins...
The Coriolis flowmeter is digital, 3/8-Inch diameter and 0.05% accuracy. It should work.
RE: Digital Flow gauge required
I've had success with their coriolis meters as an alternative to the E+H ones above.
Matt
RE: Digital Flow gauge required
Yes you can buy a E+H, ABB, Emerson Micromotion or Bronkhorst coriolis flowmeter which will measure this flow accurately- at a cost of many thousands of dollars. All these brands have a unit with a very small tube or tubes- less than 1/8"- and hence have a zero stability low enough to permit accurate measurements in the range you're looking for with reasonable turndown. The Brooks Quantim units are overpriced but do work also- to imagine their tube, think of a capillary tube about the size of a large paperclip...
At 100 mL/min you might find a liquid thermal unit which will work for pure water. Brooks has an old product, but Parker and Bronkhorst do too. Thermals will still cost thousands, but perhaps less than half the cost of a coriolis.
If you can tolerate a more modest accuracy and not much turndown, an oval gear meter might be able to do this flow for a few hundred bucks. It gives a pulsed (frequency) output, and will be blocked by any tiny particle of debris so a prefilter is essential.
If it's not deionized water, you might find a very small tube magmeter for this service, but turndown will be poor. Usually when we have small water flows like this it's water of sufficiently low conductivity that mags aren't an option.
I'd suggest based on our experience that you stay away from the laminar flow differential pressure units and the straight tube thermal units that some offer. Our experience with both these designs has been poor enough that we won't buy them again.
RE: Digital Flow gauge required
I would tolerate a +/- 3 % error if I could source one for around £500
Talking about oval gear flow meters, I found http://www.flowmeters.co.uk/oval_gear_meters.htm
Not sure about cost but will look into it.
Thanks
RE: Digital Flow gauge required
Make sure that it will work on water:
Disadvantage: Oval-gear meters are generally not recommended for water or water-like fluids, because the increased risk of fluid slippage between the gears and chamber walls. Fluid slippage will cause a slight degradation in accuracy, with low-viscosity fluids being more prone to degradation. As viscosity increases, the wall slippage quickly becomes minimal, and the best accuracy is realized. Since the oval-gear meter is really designed for higher-viscosity fluids, it can be argued that running water through them is not a viable application anyway.
http://www.coleparmer.com/TechLibraryArticle/667#a...
RE: Digital Flow gauge required
http://www.ukflowtechnik.com/sites/ukflowtechnik.c...
According to the data sheet for the oval gear above, it's designed for use on fuel oil, of which Petrol has a lower viscosity. Will get a price.
Cheers
RE: Digital Flow gauge required
RE: Digital Flow gauge required
RE: Digital Flow gauge required
I could in theory I could replace the constant head with an accurate metering pump ??
RE: Digital Flow gauge required