Mass/Flow Meter? 1

[RayRogers]

I have a need for a flow meter that can measure water: 3nL/pulse, 1 pulse per second, so that the accumulated accuracy for 30nl is better than .3 nL.
Any suggestions? We are trying weighing with a pecision scale but the water keeps evaporating. I can control the evaporation, but would prefer to buy an off the shelf instruments.

Ray

 

[Sierra]

Maybe a Thermal Liquid flow meter? (standard smallest range 0-12.5 mg/hr normally) You can ask manufacurers how low they can go. The smallest corioles meters go down to 50 g/hr, but there are rumours smaller ranges are on the way.

 

[adil4adil]

hi Sierra

what about magnetic flow meters
only if we have coductive fluid

adil4adil

 

[RayRogers]

We have solved the problem. It turns out that there is a
market in Pipetters for medical research putposes. These
managed to satisfy our needs.

 

[Rocco8]

Ray,

What is the brand of the unit that finally worked for you?

Rocco8

 

[RayRogers]

Rocco8,
We used the Matrix Impact2

http://www.apogentdiscoveries.com/LH/Impact.asp

Good enough. Go back up to

http://www.apogentdiscoveries.com

to find other things; automated ... etc.

Ray

 

[tomramey]

Ray, you might look at the small excellent meter from Belgium, avaialable in the USA at:

http://www.measureanything.com/products/44907-2284/datasheet_44907-2284_DFS2W_disposable.asp

excerpt:
The DFS-2W has a linear flow range of 0.07– 4.5 l/m (.02–1.2GPM), turndown of 64:1, resolution of 60,000 pulses/liter (227,100/Gal.) Process connection is 7mm ( 9 /32 &quot hose barb fitting.
Cheers!
Tom Ramey

 

[RayRogers]

tomramey,
Thanks, but the resolution doesn't seem adequate. The design reminds me of an idea I had to make a 0 pressure drop flow meter using a higher order control loop to drive a pump just so that the pressure drop around the pump was zero. I envisioned a smooth spiral type of rotor.
Never did anything with it though. Just an idea when we wanted to experimental monitor flow without disturbing the flow.


Thanks again
Ray

 

[tomramey]

Ray --
not a bad idea, doesn't sound to energy-efficient though, lasers, optical, magnetic, all the non-contact technologies are comig along steadily, in terms of non-invasive flow measurement. Last thing the world needs is another flowmeter, also, there are thousands of designs and embodiments. Anyway, enjoy the Veteran's Day holiday, I'm doing some landscaping/gardening myself, just checking in on email every hour or two to keep the empire rolling. Ciao!