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Dribble rate sensor.

Dribble rate sensor.

Dribble rate sensor.

(OP)
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

RE: Dribble rate sensor.

What fluid are you metering? Positive displacement meters like oval gear or roots meters are pretty good on the more viscous liquids like oils and paints if they are free of solids.
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

RE: Dribble rate sensor.

(OP)
Sheesh.. No star for this question..

Water.  Tap water...

Lots of those turbine meters out there.  They just all krap out below 0.1gal/min.   If they'd just make one fifty percent smaller we'd have it.    

Keith Cress
kcress - http://www.flaminsystems.com

RE: Dribble rate sensor.

Rotary drum meter -  good for drip flows.
This is a bit like a rotating multi compartmental bucket. In flow is directed into a a compartment to one side of the axis of revolution.
As it fills, it rotates the shaft until the next bucket is lined up and the first can drain away.

It might be similar to this: http://www.freepatentsonline.com/4613058.html but without the pics couldn't say.

It is a bit like this gas meter:
http://images.google.co.uk/imgres?imgurl=http://chestofbooks.com/crafts/scientific-american/sup4/images/THE-GAS-METER.png&;imgrefurl=http://chestofbooks.com/crafts/scientific-american/sup4/The-Gas-Meter.html&usg=__cLNbtF5I22HbCYuI78efm_vTzQg=&h=217&w=500&sz=46&hl=en&start=169&um=1&tbnid=cS2MDx54Wy65dM:&tbnh=56&tbnw=130&prev=/images%3Fq%3Drotary%2Bdrum%2Bflow%2Bmeter%26ndsp%3D18%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DN%26start%3D162%26um%3D1

I think they were originally designed for some very slow process operations like condense flow from an evaporator or distillation column.
 

JMW
www.ViscoAnalyser.com
 

RE: Dribble rate sensor.

Er, best to think of the drum meter like a water wheel and the way it rotates as the buckets fill and empty...  

JMW
www.ViscoAnalyser.com
 

RE: Dribble rate sensor.

Why not a Mag meter
0.3" (8mm) 0.009 to 6.6 gpm
Roy

RE: Dribble rate sensor.

Or better yet a 0.15" (4mm) mag meter 0.002 to 1.6 g/m
0.6 ft/sec at 0.01 g/m
3.75 ft/sec at 0.2 g/m

RE: Dribble rate sensor.

(OP)
Whoa, whoa ponies..  Did we miss the ~$200?  I can't believe those mag meters or ultrasonics don't exceed this price by half a magnitude.

This is for embedding into a product that will likely be plumbed with 1/8" or 1/4" stainless steel tubing.

jmw;  Those Flow Technology sensors look really nice.  Not even their reps have prices... Doesn't bode well.

danw2;  Thanks for the Dwyer link.  They have a nice unit that's about $250 that could work.  I wish I could dial down the price by dialing down the accuracy.  I'm happy with about 2~3%.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Dribble rate sensor.

The FTI US meters are relatively new.... but I guess the price is going to be pretty high...>$200.

So, back to a low cost meter...you didn't say if it is flow total or flow rate but if I assume flow rate, try a variable area flow meter.
These can be had for a few dollars if you don't need too great an accuracy.
Try Platon or Rotameter (now part of Emerson I guess...oops! Emerson appear to have discontinued the Rotameter VA meters.... and they were a top quality product...) so do a search for Variable Area meters.
 

JMW
www.ViscoAnalyser.com
 

RE: Dribble rate sensor.

How about a peristaltic pump?
A Search for "low flow peristaltic pump" produces plenty of results, some with prices.

RE: Dribble rate sensor.

(OP)
jmw; Ah.. now that might be the ticket. I've seen those before.  I didn't know that's what they were called. They make sense now. DOH!
Now if I can just find an electrificated one.

FrancisL; I'm afraid a peristaltic pump wouldn't have the lifetime needed since this thing will run thousands of cycles/day.  Aren't PPumps really hard on their wetted element?

Keith Cress
kcress - http://www.flaminsystems.com

RE: Dribble rate sensor.

Not sure about peristaltic pump tube lifetime so I would ask a supplier.  

RE: Dribble rate sensor.

You said you wanted a flow meter, now you are talking about pumps.
Solenoid type metering pumps can have a very low overall flow rate.
There are other very low flow metering devices such as Clarkson feeder.
Perhaps give us some more details on what you are trying to do.
Regards
Roy

RE: Dribble rate sensor.

Itsmoked wanted a flowmeter and I started talking about pumps!
Perhaps that is a red herring, but the reason I brought it up was that many years ago I was involved in a project which needed a very low flow the speckler - for spraying ink onto mini eggs! And the solution we found was a peristaltic pump.
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.

RE: Dribble rate sensor.

Emerson didn't discontinue the VA flowmeter.  The brand name is Brooks.  Dwyer make cheapie injection-molded acrylic meters for about $50, but so do Brooks.  
Here's a link.  And no, I have no affiliation.  
http://www.brooksinstrument.com/category11.asp
Pay a little extra for the integral valve and you can regulate the flowrate from the meter.   

RE: Dribble rate sensor.

Sorry, they discontinued the Rotameter (a trade name and not a generic for a VA meter) manufactured originally by Rotameter, a part of GEC Automation, then Fisher Controls, then KDG, then KDG Mobrey and then Solartron Mobrey.
The next corporate shenanigans lead them to Emerson and on Emerson's Mobrey site you will see them under discontinued products.

JMW
www.ViscoAnalyser.com
 

RE: Dribble rate sensor.

Just looking through the Cole Palmer catalouge, they have a pelton wheel sensor in several low ranges
13 - 100 ml/m K-32703-50
50 - 500 ml/m K-32703-52
For US$240 + US$120 for a display
www.colepalmer.com  (800) 363-5900
page 718 of the 2007/2008 catalouge
I doubt you will get the 20:1 turndown you ask for in a cheap meter.
Regards
Roy

RE: Dribble rate sensor.

Page 733 of the 2010 on-line catalouge.
Roy

RE: Dribble rate sensor.

(OP)
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

RE: Dribble rate sensor.

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

JMW
www.ViscoAnalyser.com
 

RE: Dribble rate sensor.

(OP)
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

RE: Dribble rate sensor.

Look at Coriolis meters if not already mentioned.

RE: Dribble rate sensor.

(OP)
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

RE: Dribble rate sensor.

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
www.ViscoAnalyser.com
 

RE: Dribble rate sensor.

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.


www.controldraw.co.uk
Francis

RE: Dribble rate sensor.

(OP)
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

RE: Dribble rate sensor.

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
www.ViscoAnalyser.com
 

RE: Dribble rate sensor.

(OP)
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

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