Control.com - Nerds in Control

I would like to find a sensor to measure the density of sludge flowing in the pipe.

The specification requirements:
Range: 0.02-1%¡¢0.1-5%¡¢0.2-15%£»
Time delay: adjustable between 0 and 10 minutes
Measuring Precision: better than 1% of the full range
Accuracy: 0.5% of the full range
Operation temperature: 0¡«40¡æ
Power Supply: AC220V¡À10V

So would I. I've been trying to find a good sludge density meter since 1974,
without success.

If you can measure bulk density, you can use a coriolis meter, or an
ultrasonic density meter, in some cases. Nuclear densitometers will NOT
work.

But the real problem is that you want to measure percent-solids. That's a
calculated variable that simply cannot be done in wastewater sludges,
because the dry solids density (required for the equation) varies
continuously.

So you have a variable with two unknowns...

You must tell your client, or your supervisor that you can measure bulk
density to reasonably good precision, but that you can't measure percent
solids better than +/- 10% of scale. On the scales you are talking about,
that should get you out of trouble.

Anybody that can actually make this measurement to acceptable precision (+/-
1% of reading) let me know.

Walt Boyes
Editor in Chief
Control magazine
www.controlglobal.com
blog:Sound OFF!! http://www.controlglobal.com/soundoff
_________________

Putman Media Inc.
555 W. Pierce Rd. Suite 301
Itasca, IL 60143
630-467-1301 x368
wboyes@putman.net

Toshiba makes a Microwave density meter, it installs similar to a mag.

Toshiba’s Microwave Density (consistency) analyzer series, utilizes the principle of microwave phase difference measurement to determine the density (consistency) of process fluids flowing through the spool style detector. This exploits the way a fluids density (consistency) affects the propagation of microwaves as they pass through the fluid. This provides the reliable measurement of a fluid’s density (consistency) by monitoring the microwave phase between the original wave and the one that passed through the measured fluid. This method provides excellent measurement precision exhibiting very high repeatability and reliability with minimal maintenance.

http://www.toshiba.com/ind/product_display.jsp?id1=9&id2=90&am p;id3=158

I don't know how well it works, their specs look fairly good.

Thanks. I think the LQ500 is OK for me.