Flow Meter for Viscous Emulsion

• Maintain zero differential pressure across a gear pump at a known speed?
• Coriolis mass flowmeter?

Hello PW Slack,

Differential pressure is 7 bar.

Thanks

• Maintain zero differential pressure across a gear pump at a known speed? The principle is that if there is no differential pressure across a gear pump then their is no slip at the pump. Then, the speed of the pump can be used to work out the flowrate given the displacement.

technology: thermal dispersion.

claimed flow rates as low as 10 cc/day . . .

http://www.coleparmer.com/catalog/product_view.asp?sku=3290001

Density:- 1.04 to 1.07 g/ml

Sp. Gravity:-0.948

I don't think the numbers above can be correct unless I am missing something.

+1 for Coriolis

Not the cheapest meter but a good way to get very good accuracies at low flow rates.

The issue is your viscosity. If the actual DYNAMIC Viscosity really is 1500 cP then it may be tough to get your flow though a small enough sensor to get good accuracy at the low flow with your available line pressure. The lower the viscosity the smaller pipe you can use and the better acc you will have.

You will need a sensor tube about 0.10 - 0.16 inch in diameter.

Good Suppliers are:

Siemens- http://www.automation.siemens.com/w1/automation-technology-coriolis-18645.htm

Micro Motion - http://www2.emersonprocess.com/en-us/brands/micromotion/Pages/coriolis-flow-density-measurement.aspx

E+H - http://www.us.endress.com/

Cheers,

Eric

The Siemens coriolis meter used for low flow probably will not work. The tube diameter is only 1.5mm, (0.06"), typically needed for low flow rates like this.

But the pressure drop is excessive for the range of viscosities; as you can see from the chart below. The user has only 7 bar pressure to work with.

0.5Kg/hr at 500cSt takes 3bar pressure, which might be OK, but the upper flow rate of 4Kg/hr at 500cSt takes 12+ bar.

The pressure drop situation at 1,000 cSt is untenable.

The 1.5mm Siemens low flow Coriolis sensor was not suggested for the very reason you mentioned, delta P is insufficient for these viscosities.

The 3mm (0.10") and 4mm (0.16") sensors tubes were suggested as a viable solution providing acceptable accuracies and reasionable delta P values. Additionally as the viscosity as stated is most likly a static viscosity and not dynamic the actual delta P will be lower then the worst case calculations once the flow starts moving.

Smith Meter Erie PA makes a flow meter for viscous emulsions.

What type flow is it, is it batch or continuous? If batch you could use load cells on supply tank or receiver tank. If it is continuous you may try a Doppler type.

A few questions:

1. "What sort of flow meter would be giving the accurate measure?" What sort of accuracy do you want?

2. What is actually conveying the fluid? (Pump, gas pressure, gravity?)

3. You mention 7 bar nominal pressure (system pressure?), then 7 bar differential pressure. Is this across the pump, the flowmeter or what?

PWSlack's suggestion to use a gear pump is very good, especially with the range of flowrate, viscosity and pressure involved here.