Flowmeter Selection
Flowmeter Selection
(OP)
Hi all,
This is my first post here, and I am at the beginning stages of replacing a currently installed flowmeter. We are looking at expanding the flowrate in the system and are needing to change our current installed flowmeter. Some background information on our requirements:
Fluid Temperature=150 Deg Celsius
Flowrate= 0-18 L/min (preffered) 0-12 L/min (mininum)
Fluid is water and or ethylene glycol at various mixture ratios. (ie non constant density)
Line size: 0.5" NPT or possibility for 3/4" NPT
We currently have a turbine meter installed that has a range of 0.38-11 l/min. I understand that turbine meters are not accurate at the lower ends and thus is a driving factor in replacing it.
I am currently considering magnetic flowmeters, positive displacement flowmeters, and other turbine meters. Due to the nature of the high temperature glycol we are trying to minimize pressure drop if possible.
Thanks for your assistance everyone!
This is my first post here, and I am at the beginning stages of replacing a currently installed flowmeter. We are looking at expanding the flowrate in the system and are needing to change our current installed flowmeter. Some background information on our requirements:
Fluid Temperature=150 Deg Celsius
Flowrate= 0-18 L/min (preffered) 0-12 L/min (mininum)
Fluid is water and or ethylene glycol at various mixture ratios. (ie non constant density)
Line size: 0.5" NPT or possibility for 3/4" NPT
We currently have a turbine meter installed that has a range of 0.38-11 l/min. I understand that turbine meters are not accurate at the lower ends and thus is a driving factor in replacing it.
I am currently considering magnetic flowmeters, positive displacement flowmeters, and other turbine meters. Due to the nature of the high temperature glycol we are trying to minimize pressure drop if possible.
Thanks for your assistance everyone!





RE: Flowmeter Selection
RE: Flowmeter Selection
Pressure rating?
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Flowmeter Selection
The flow rates must be close to 0 and upwards to 18 l/min or 4.75 USGPM for my imperial friends.
-The flow rate would me maintained at the desired setpoint with minimal fluctuation. The response time of the sensor is not critical.
Cheers,
AWloo
RE: Flowmeter Selection
RE: Flowmeter Selection
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Flowmeter Selection
Cheers,
AWloo
RE: Flowmeter Selection
With this kind of problem I tend towards simpler. I'd use a V-Cone and know the when the fluid composition matched the input parameter I'd get better than 1% uncertainty and other than that I wouldn't.
David Simpson, PE
MuleShoe Engineering
Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat
RE: Flowmeter Selection
Currently we are measuring turbine flowmeter which meausures volume not mass flow. Attached is a linearizer which provides a 0.1% accuracy. The current manufacturer of the valve does not have a size that matches are new requirement and we are looking elsewhere.
I will look into the V-Cone.
Cheers,
AWloo
RE: Flowmeter Selection
Talking about "accuracy" is quite imprecise. Typically we talk about "uncertainty", "repeatability" and "hysteresis". An equipment manufacturer that boils those three (measurable) components into "accuracy" (not measurable) would cause me to run screaming from their equipment. It is just smoke and mirrors. I've used turbine meters a lot and they definitely have a place. I spec them when I can tolerate an uncertainty of around 5%, a repeatability around 95%, and considerable hysteresis (it takes a LOT more force to start a turbine from a dead stop than to change it's speed once running).
David Simpson, PE
MuleShoe Engineering
Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat
RE: Flowmeter Selection