Flowmeter Specification
Flowmeter Specification
(OP)
Hi,
In my plant, we need to buy a flowmeter and I have difficulties to determine the minimum flowrate in the line. Indeed, data retrieval software always gives "zero" as min flowrate.
So I was wondering:
- Is it mandatory to specify the minimum flowrate in the process data sheet of a flowmeter?
- Is it possible to assume a turndown ratio without knowing which technology will be chosen?
Thanks
In my plant, we need to buy a flowmeter and I have difficulties to determine the minimum flowrate in the line. Indeed, data retrieval software always gives "zero" as min flowrate.
So I was wondering:
- Is it mandatory to specify the minimum flowrate in the process data sheet of a flowmeter?
- Is it possible to assume a turndown ratio without knowing which technology will be chosen?
Thanks
"We don't believe things because they are true, things are true because we believe them."





RE: Flowmeter Specification
If you know the current meter and it's turndown, that gives you at least an idea where your current 'zero' (which is more a minimum turndown of the meter than a true flow measurement) may lie. With that information, you have a better chance of the next meter covering your turndown range since different metering technologies have different turndown capabilities.
RE: Flowmeter Specification
I generally have to consider the need-to-know lowest velocity (and of course, the normal and upper limits) before choosing which technology to employ...
Good on ya,
Goober Dave
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RE: Flowmeter Specification
Do you guys know any minimum velocity criteria for the coriolis flowmeter?
"We don't believe things because they are true, things are true because we believe them."
RE: Flowmeter Specification
See attached for a good discussion.
http://ww
Good on ya,
Goober Dave
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RE: Flowmeter Specification
David
RE: Flowmeter Specification
"We don't believe things because they are true, things are true because we believe them."
RE: Flowmeter Specification
Good on ya,
Goober Dave
Haven't see the forum policies? Do so now: Forum Policies
RE: Flowmeter Specification
Need a little more information to really help you.
RE: Flowmeter Specification
Information required from the Process Engineer to be provided in the flow data,
includes the minimum, normal and maximum flows, pressures, temperatures and alarm set points.
The positive displacement flow meters now are the best flow meters currently
available for fluid flow measurement, particularly for crude oil. They are highly accurate, have a good rangeability (turndown) ratio andcan handle high viscosities.
Turbine flow meters have good precision and turndown for hydrocarbon fluid.
They are suitable for both gas and liquid measurement, they have a wide turn down ratio.
Ultrasonic meters are finding applications for accurate measurement for both liquids and
gasses. Accuracy and turn down make this type of meter attractive to legal metrology flow
applications.
RE: Flowmeter Specification
RE: Flowmeter Specification
Flowrate ranges from 300 to 2000 kg/h
Pipe size ranges from 1 to 2 inches
Viscosity ranges from 6 to 20 cSt
Temperature is around 130 degC
"We don't believe things because they are true, things are true because we believe them."
RE: Flowmeter Specification
Your Fuel Oil application would be a good fit for one of our Positive Displacement Gear Meters. Unlike most PD Gear meters, we guarantee an accuracy of ±0.3% of reading over the entire 200:1 operating range of our gear meters.
The flow range and viscosity of your application would work in our 1/2", 3/4" or 1" port gear meters. You will see an increased pressure drop created by the meter as you go to a smaller port, but a smaller port sized meter does have a more economical price.
Let me know if you have any questions.
ht
RE: Flowmeter Specification
Apart from price, may I know what are the advantages of PD type in comparison with coriolis type?
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RE: Flowmeter Specification
1. Lower flow rate capability, able to measure below 1 cc/min
2. Wider operating range allows one Max meter to replace several others
3. Lower pressure drop reduces energy lost through metering
4. Completely immune to vibration
5. Robust designs with pressure ratings to 7250 psi
6. Offers bi-directional capability with a fast response to change in direction
7. Faster response to flow changes with user adjustable dither and damping settings
8. Meter output linearized within 0.2% over a 200:1 range
RE: Flowmeter Specification
with a PD meter, 1 turn = 1 fixed volume. That's why you can have such a high turndown ratio...which your application needs.
I converted your flow rates.. and at max you're about 10 GPM. I'd go with a 1/2" or 3/4". The 1" is probably too large.
RE: Flowmeter Specification
FYI, I have just checked my company general spec, and it recommends Coriolis for combustibles.
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