density and process measurement

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Thread Starter

aki_lala

I am trying to do a final year project on density measurement equipment. But then, i was wondering, does density affect our process measurement? How do i relate my density test equipment to process?

Or should i just look for another idea. Though i have none -_-;
 
> I am trying to do a final year project on density measurement equipment. But then, i was wondering, does density
> affect our process measurement? How do i relate my density test equipment to process?

OK, firstly density is measured both as a direct measurement and indirect.

Direct is where density is the parameter of interest. You may need density for mass flow calculation from volume flow for example and you may need to correct it from the temperature at which it is measured back to a reference temperature.

Indirect is where the density is not what you are interested in but where it correlates with some other property which is of interest but which, for whatever reason, you cannot measure directly.

Examples are Degrees Brix, Twaddle, %mass or % volume. For example, to determine NaOH concentration you may find density is the best indicator of this or the most convenient way to measure it. This is because the density is a property that changes with concentration. Of course, it also changes with temperature. So again you need to convert to the density at a reference temperature and then use the density relationship with concentration to find the concentration. It is a very good way, for example, to control NaOH dilution.

The next step is to ask what method you use to measure density.
Measured inline a common method is vibrating element i.e. the digital density meter method (as per ASTM D4032 for lab measurement) but you could use a variety of techniques. If you like, indirect measures of density such as with ultrasound, gamma ray devices etc. all of which are sensors with some properties which change with density.
That's also true of the vibrating element sensors. Frequency changes with mass which changes with density. But yes, there are other effects on the sensor to account for such as velocity of sound, viscosity, temperature, pressure and so on.
In other words, the effects of various parameters on density of the fluid and the effects of various properties on the sensor itself.

Don't know if this helps or is what you meant but it might get you started.
 
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