Dribble rate sensor.

[itsmoked]

I'm finding it extremely hard to find a flow meter good for the area around the 0.01~0.2 gallon/minutes(150psi). [~6 fluid oz/min]

I've searched high and low.

I'm amazed places like GEMS have not addressed this region.

I'm starting to think I have to design one... Right after I kill myself.

~$200 limit.

Names?


Keith Cress
kcress -

http://www.flaminsystems.com

 

[itsmoked]

Thanks guys. I need a digital or analog out so the VA type flow meters won't work.

roydm; those Cole Palmer units look exactly like the Dwyer units I saw. I kept thinking "Cole-Palmer" but never actually looked because I figured the mark-up would be punitive! Interestingly their prices for the Dwyer units are about $50 less(!!) than the discounted prices Dwyer offered.


This is for a commercial drink dispenser machine. Hence the cost sensitivity.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[jmw]

VA meters have analogue output options, they're not all just visible float designs.


JMW

http://www.ViscoAnalyser.com

 

[danw2]

No prices on-line for Kobold, but here's a plastic quasi turbine, pulse output meter:

http://www.koboldusa.com/datasheet/DPL_datasheet.pdf

Spec sheet says low end flow is 0.014 oz/sec.

This one here fits your flow range pretty well, but the construction looks higher cost than the one above:

http://www.koboldusa.com/datasheet/DF_datasheet.pdf

Dan

 

[itsmoked]

jmw; I haven't found any. The Dwyer guy said he had a 45 dollar unit. Then when he showed it to me I said, "Yeah, but where's the electrical out?"
The response, "Oh that's right. Never mind."

danw2; That first one looks the part! The pressure is even right. I will hunt down a price on that. Thanks.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[djs]

Omega Engineering has a turbine flow meter that goes down to 0.07 GPM. $267 list.

http://www.omega.com/ppt/pptsc.asp?ref=FPR301_302_303_304&Nav=gref02

Also check out

http://www.omega.com/ppt/pptsc.asp?ref=FTB300_Series&Nav=gref02

 

[JLSeagull]

Look at Coriolis meters if not already mentioned.

 

[itsmoked]

A guy just handed me a stainless steel rotary flow meter that he said costs about $40... !!
It looks cast/machined. It even has a hall switch in it.

I'm amazed. It's Italian.



But! As I woke up this morning it dawned on me that this whole thing is being driven by an (inside) gear pump. Maybe someone can tell me if they're considered to be enough of a positive displacement pump to be able to count the revolutions and infer the flow indirectly.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[jmw]

who is the manufacturer?
PS: PD meters and PD pumps can employ very similar geometry but one is motorised to drive the fluid through the pipe and the other is driven by the fluid flowing through the pipe.


JMW

http://www.ViscoAnalyser.com

 

[FrancisL]

itsmoked suddenly thought!!

"But! As I woke up this morning it dawned on me that this whole thing is being driven by an (inside) gear pump"

As I said before, "As ever a better understanding of the process is needed, for example what is the water for and what does actually set the flow rate."

A nice little diagram would have helped a lot. It still would.

What accuracy are you seeking? A simple rotation counter on your gear pump might be all you need. In fact you might not even need that if you can derive the flow some other way.

http://www.controldraw.co.uk

Francis

 

[itsmoked]

Yes I do "suddenly thought". Usually between waking and getting up. Or in the shower.

I'm not at liberty to say more than this is a drink dispenser that runs between 60 and 140PSI with a time varying profile thru a nozzle.

I control the pump via motor speed and I have pressure feedback. If I'm controlling the effect at a nozzle in a pressure system, I can't really see what I'm going to do with flow. Don't I focus on the pressure profiles? Flow is too slow and too inaccurate for controlling to a repeatable output profile when the nozzle varies with time.

It would seem flow would be much more valuable in the case where I have an unrestricted flow between, say, two tanks and I want to profile that or totalize it, another words, flow that would see little pressure variation.

This is rather like an electrical system where you need a specific voltage profile. You wouldn't add a resistor and convert to current feedback if voltage does the trick.

I'm adding flow here more as a check, as back to the voltage regulator, you might look at the current to limit over current. So the more I think about it the more using the pump as a flow meter seems to fit the bill.

No diagram needed. Pump-> Flow meter(or not)-> pipe -> pressure sensor-> nozzle.



Keith Cress
kcress -

http://www.flaminsystems.com

 

[jmw]

Er, what type of pump? If you have a PD pump, gear type, peristaltic etc. why bother with a flow meter? flow rate is controlled by the pump and all you need do is monitor pumnp speed.

JMW

http://www.ViscoAnalyser.com

 

[itsmoked]

Excellent! That's what I'll implement.

Since I have a flow sensor in hand I'll use it also and have cage fights between the two!

Keith Cress
kcress -

http://www.flaminsystems.com