Which volumetric flow meter for measuring high velocity water through a pipe? Fuji Ultrasonic?

[pa5tabear]

We want to measure water flow through a 2" pipe. The volumetric flow will be used as feedback for the multi-pump control scheme.

It's a high pressure system (~600 psi) and the water is probably moving around 10 m/s.

I was recommended to use Fuji Ultrasonic flow meters. Does this sound like the right choice?

 

[pa5tabear]

If it makes any difference, we are dealing with "hot water".... between 140 and 180°F.

Also, the pressure should be fairly constant, but the flow might range from 0 to 120 gallons per minute.

 

[zdas04]

That's a lot of money for a pretty simple application. A V-Cone would work. A Mag Meter would work. Even a turbine meter would work (but the latency might be a bit high for effective control). My first choice would be a V-cone. My last choice would be an ultrasonic (your temperature range is wider than I like for UT). A temperature compensated Coriolis meter would work, but I'm not sure why you'd spend that much money on such an easy application.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
The plural of anecdote is not "data"

 

[Niwot]

2 issues I see:

1) You might want to check your #'s. 10 m/s is high velocity for water, not that I haven't seen it before. However, I calculate your volumetric flow rate of 120 GPM to be roughly equivalent to 3.5 M/S.

2) I believe the Fuji ultrasonic meter you're refering to is non-intrusive (clamp-on)- measurement without contacting the fluid. They are cheaper than inline ultrasonics. Are you trying to avoid pipe penetration (drill, cut, weld or flange) to install a flow meter? In principle, clamp-on ultrasonics tell a good story, but they generally are not used where high accuracy is required. I've seen them used more for maintenance - direction of flow, determining an approximate flow for future meter sizing, etc. Variance in Brinell pipe hardness and ID, pipe surface condition, scale build-up, etc. can diffuse the sound waves and affect the measurement. Ignore this if you are looking at an in-line ultrasonic or if your not concerned with accuracy. I agree with David that a true in-line ultrasonic meter would be overkill. IMO, this would be a good application for DP (avg. pitot, V-cone, etc.).

Maybe David has experience with clamp-on ultrasonics that differs from mine?

 

[zdas04]

No, I don't. They remind me of the joke where a drunk is searching under a street light for something and another drunk decides to help search. After while the second drunk asks "are you sure you lost it here?" and the first drunk replied "no, I lost it over there, but the light is better here". In other words, I've found strap on ultrasonics to be crap measurement, but they are easy to install. Any ultrasonic finds changing conditions difficult. With varying temperature I am pretty sure a strap on ultrasonic would consistently give you numbers. I'm not quite as sure that those numbers would consistently relate to the fluid flow.

As to pitot tubes, I am starting to see a lot of them going in. Thankfully, I am also seeing a lot of them come back out after a few months. No one in my experience does very good at caring for and feeding pitot tubes. They have to be recalibrated for every change in density or fluid composition. For wellsite use, the fluid can change more than the meter can tolerate several times per second. They are fine in a very well controlled, very clean service, but any variability disqualifies them in my opinion. The temperature variability that the OP mentioned would disqualify them I think.

I forgot to mention in my first post, that I've had pretty good results with Vortex meters in water service over the last few years.

If I had to rank the choices for this application I'd look at V-Cone, Vortex, Mag Flow, [eight or nine blank spaces], or Coriolis Meter.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
The plural of anecdote is not "data"

 

[LittleInch]

The issue is that like most things it depends on your individual circumstances. If you don't want to or can't insert a device in the flow then you are looking at mag flow or ut meters. Is it a process flow rate you want or a fiscal quality, is there a decent straight length up and down from your meter point, is the fluid 100% liquid (a lot of meters don't handle bubbles well). Any reason you can't use an orifice plate meter?

We only have about 10% of the info. U T meters in my experience work well, but need a good connection to the pipe surface, no bubbles in the liquid, not much swirl in the liquid and single path strap on will be about 3 to 5 % accurate. If the location is extreme or liable to be hit or moved, ut meters can easily loose signal.

For water try mag flow before ut.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way