How Do You Choose a Flow Meter?
prepared before you try and pull the trigger.
Where Do I Start?
Choosing a flow meter can be a
very overwhelming prospect. Sometimes it can be hard to know where to start.
You have to wade through finding out which flow meter technology out there
might best serve your application and your budget. Then there are countless
manufacturers out there with multiple models all offering something a little
different. You also have to ensure that the specific variable of your process
fall in line with the specifications of each individual model. Knowing what
information you even need to start with can be difficult.
Make A List and Check it Twice
Nobody likes to spend time or
waste money that they could have saved with a little preparation. When it comes
to finding the best fit for your process application, being organized and
thorough can have big payoffs in making sure that all factors are appropriately
compensated for in your choice. Accidentally overlooking some variable that
ends up in equipment malfunction, damage, or failure can be avoided by asking
the right questions at the beginning. Below is a farily comprehensive list of
questions to help you build a complete application profile for an optimum
- What do you have in your
budget to spend? While it is tempting to think that price needs to always
be the first consideration and to think that the lowest priced option is
always the way to go, that can lead to headaches down the road. Cheaper
models, options, or technologies may not provide the same length of
service life, require more maintenance, or may require more downtime for
things like calibration. These things all cost money in the long run and
should also be added to the total lifetime cost of the instrument. Ask
what the average life span of the model you are looking at is.
- Also ask about warranties. How
long is the instrument covered and does the company you are purchasing
from have a known customer service record for supporting their
instrumentation in an accessible and personal manner. This can make all
the difference in ensuring that an instrument has been correctly
installed and to easily troubleshoot any questions that come up as part
of that process.
- Another aspect is how long
will it take to install? Will it require a shut down of a critical
existing process that will cost money if it is shut down or can it be
installed without this issue?
- It is important to think in
terms of total value and not just the initial cost. What may be cheaper
at first may cost much, much more in the long run.
- If you are looking to replace
a part that has shut down a process, lead-time for the replacement is
also an important consideration. Can you get it fast to get the process
back up and running?
- Wouldn’t it be nice if you
could try one out first to make sure it works? Some companies are open to
the idea of suppying short term demo units to ensure that it is the
correct solution for the application.
o Who will be using it? What do they need to use it for? Where
will it be placed?
o Does the process require totalizing or batching capabilities?
o Is visual rate indication needed only? Is a switch or
transmitter needed? Is local or remote indication needed?
o Getting the basic layout of the process and the people involved
will help you in selecting certain features.
Immediate Characteristics/Surroundings to the Place of Installation
o What is the size of the pipe and what is it made out of?
o Is the environment around the area stable or variable? Is there
danger of explosion? Is the area a harsh environment?
o What length of straight run of pipe is possible before and after
where they instrument will be placed?
o Will there be other types of instrumentation placed close to the
flow meter on either the upstream or downstream?
o Are there space limitations where the installation will need to
be that restrict the size that the instrument can be?
o Will the installation are require a certain angle that the
instrument will be installed at?
o This is an important one. Many times it is the only factor
considered. While it should be factored, it is still important to get a larger
picture of the application than just the media characteristics.
o Is it a liquid, gas, vapor, steam, slurry, multi-phase to be
o Is the media clean or dirty?
o Is the nature of the media corrosive?
o What is the media density, viscosity, temperature, pressure, and
do these remain consistent?
o Is the media conductive and if so, how much?
o Is the media newtonian or non-newtonian in nature?
o Does the media have any coating or crystallizing properties?
o Does the media have any foriegn objects? If so, what are they
likely to be and how large are the particles?
o Is there any suspended particulate matter? If so, what are they
and how large will the particles be?
o Any ferrous material in the flow?
o Is it likely that the media may contain air bubbles?
o Is the process designed so that the pipe will always be totally
full of the media?
o Will the flow rate remain relatively constant?
o Is there a chance of pulsating flow?
o Will the flow be largely laminar or turbulent?
o What sort of turndown is needed to accomodate the range of flow?
Minimum flow? Maximum flow?
o Is the flow in one direction or is bi-directional capacity
o Is pressure loss from the flow meter an important consideration
to the process?
o How exact of a measurement does your process require?
o What sort of regulatory compliance are you subject to? Do you
have hygienic requirements? Explosion-proof concerns?
o Who needs to see the data and how do they need to see it?
o Do you already have a certain communication protocol in place
that you need the instrument to also have?
Need Help? Use A Trusted Technical Source.
still sound intimidating and like a bit too much to tackle on your own? Don’t
worry. There are many knowledgable sales engineers out there who know exactly
how to guide you through this process to the best all-around choice for your
exact process. The field of instrumentation is always evolving and consulting
someone is always an advantage. KOBOLD has experts at your disposal standing by
to help you. However, even when using the services of a professional, it is
still key to have most all of the information gathered before you pick up the
phone, so the process can be as smooth and timely as possible.