Fast Flowmeter application

Sometimes a process is thát critical and each deviation in flowrate must be noticed and compensated for.
A customer application involves water with potentially some short disturbances in flowrate.
With water as medium, lots of measurement methods can be used to measure flow, why chose Ultrasonic measurement then?
The reason is in the additionla requirements.

Requirements mark the playing ground

There’s always more than one requirement when a flowmeter is being considered. In this Fast Flowmeter process, speed was obviously key-requirement number one!
Next to a quick response, it would be beneficial that the flowmeter would disturb the water-flow the least possible.
In addition, and related to that, a minimal pressure-drop could be allowed, pressure plays an important role in this customer’s process.
A last requirement has to do with accuracy and scaling. The current maximum flowrate is 12 liters per minute. This may rise a bit in the future, so additional capacity is not bad, but 12 l/min should be in the accuracy-range of the instrument.

Weighted requirements

In itself the above requirements would qualify for four types of Flowmax ultrasonic flowmeters.
To come to a ranking, the requirements are weighted, the most critical requirement is counted five times, the least important only once.
By judging with weighted requirements, it became obvious that the Flowmax 44i has the best overall score.

From good to better

All four considered flowmeters are equally fast, have an open bore and no moving parts. On that behalf, they are all good.
What made the difference is the close-to-straight bore of Flowmax 44.
The straight bore of DN10 matches ideally with the piping inner diameter. This results in low pressure-drop and in less noise in the flow itself.
Great how a non-critical parameter can make a small diference at the end.

How fast is Flowmax-fast?

The application may have minor disturbances that may last no longer than 0.1 second. Or 100 milliseconds to make it sound more 😉
Flowmax sensorics deliver 250 internal measurement values every second, that’s one reading every 4 milliseconds (!)

A minimum damping level is hard-coded in the Flowmax calculator, averaging each 4 measurements and providing the outcome as an output to the world. That makes the fastest rate 4×4= 16 milliseconds.
Do you have 3.05 minutes? Watch this video of the importance of milliseconds for athletes.!

Reduced speed on demand

On demand, the user may want to increase damping of the signal.

With increased damping , the meter still takes 250 measurements per second.
The difference is that a lot of things happen inside the calculator, with an end-effect resulting in one output signal every 2 seconds for example.
This damping is an important factor in PID-control cycles.

Optional: PID in the meter itself

PID software is optionally available in the Flowmax instruments. Tell us your aplication and get fast advise.

(This may take more than 16 milliseconds)