measuring very low flow rates in 3/8" tube

R

Thread Starter

Raghavender

hi,

I am looking for a flow meter which can measure very low flow rate from 3ml/min - 10ml/min in a tygon tube using a peristaltic pump. The flowing liquid is blood. So if anyone come across please let me know.

Thanks a lot.
 
R

Robert Scott

If I understand peristalitic pumps properly, their flow rate is directly determined by the dimensions of the pump and the tubing and the rotational rate of the pump. As long as the tube remains full of fluid, the flow rate cannot vary. So measuring the pump rotation would be equivalent to measuring the flow rate. Or, are you interested in an independent measure of flow to verify that the pump is working properly?

Robert Scott
Real-Time Specialties
Embedded Systems Consulting
 
G

Gerald Beaudoin

I assume that if you are pumping blood that you have access to the typical hospital environement equipment... a regular volumetric infusion pump used for IV infusions would certainly give a good measurement. All of the ones
that I saw during numerous chemo treatments all had a data port on them (RS232), which I assume would give you access to the various parameters and values. You may need some tubing adapters but I think you could easily measure in the range you mentioned.

Gerald Beaudoin
 
J
I don't think you'll do it cheaply. Endress & Hauser Promass 64 (http://www.endress.com/) should do it. We use these on liquids and gases for low flow with good results. According to their info,the "A" or "F" size should work. Also, the pump output may need "smoothing" to reduce pulsations (ask the E&H person).
 
T

Thong Phat Co., Ltd.

Dear Raghavender,

If the fluid is blood, the only flowmeter is a weight scale.

Regards,

Hung Lam
 
W
Well, that's not true. I have seen magnetic flowmeters designed specifically for in-body blood measurement. I've seen ultrasonic flowmeters (transit time or correlation) for the same purpose. None of these are widely commercially available...most are custom designed for a hospital, surgery, or research facility.

Walt Boyes
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T

Thong Phat Co., Ltd.

Hello,

The big problem of any in-line flowmeters, including magnetic flowmeters, for humand blood measurement is sterilization. I am not sure there is any approvals or standards to sterilize an in-line flowmeter. I am doubt that ultra sonic flowmeter will work reliablly with such low flowrate 10 ml/ min = 0.17 cm3/sec ~ 2,3 mm/sec fluid speed in 3/8" hose?

Regards,

Hung Lam
 
You might want to check out the new Micro Motion LF series meter. These meters are extremely accurate (the most accurate flowmeter you can buy) and can measure in mass or volumetric.

Cheers!
 
R

Research Dept

Dear Raghavender,
Blood is not a problem. We can design it but it will be up to you to get the approvals with the relevant authorites. Our technology can measure "weeping" flow with true zero stability and we have overcome temperature fluctuation problems using our patented technology.

Phil Hughes
http://www.eesitec.com
 
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