Replacement for Nuclear Density Meters

[BarCad]

As a potential replacement for nuclear gauges (We use Texas Nuclear Devices to monitor Brix (Density) in refining sugar), Coriolis meters show promise. Does any one have any experience with Coriolis meters as far as maintenance/reliability goes. Please share your success or failure stories.

 

[nonnukeguy]

There are many people using capacitance to measure the density of various materials including asphalt and ceramics. One of the leaders in this field is TransTech Systems. They have a new product that measures the density of asphalt by using capacitance. If you contact them they may be able to help you out.

http://www.transtechsys.com

 

[jmw]

Many nuclear devices, especially in the sugar industry, are being replaced withh vibrating element density meters and viscometers. "Coriolis" density meters exploit the same principal but pipe size is often such that they are not always the most cost effective solution. Dedicated density transmitters can be flow through or insertions. A search for density meters should bring you a numer of manufacturers. Try

http://www.solartronmobrey.com

You can also consider refractive index devices such as K_Patents.

 

[hjason]

I went through the same scenario at a South African sugar refinery about 2 years ago. The NDM we had was notoriously unreliable.

We replaced it with a coriolis meter and have never looked back. It controlled to a setpoint of 67 brix within reasonable limits.

We had to install traps before the meter to prevent foreign matter from blocking the tubes, but that's about it. It proved very reliable.

One other issue we picked up - when the brix fluctuates, the meter is usually blamed first. If your refinery uses sweetwater to dissolve the raw sugar, check the fluctuations in sweetwater brix. You may be surprised by what you find.

 

[jmw]

Mass meters often are of twin bent tube construction which can make them vulnerable to obstruction, especially if flow is pressure drop driven, as they begin to block the flow drops and more deposition occurs. Straight tube designs with a pump are better for by-passes as they are more easily kept clean and cleaned (with a long bottle brush.
You should also be sure that the software is up to spec.
Many coriolis mass flow meters also offer themselves as "coriolis" density meters. Be aware that some do not invest in a full density calibration, do not have full software capability for the calculations you need, and may not be as hgood at density as you would like. Then too they are often installed in a by-pass for density measurement which can lead to problems such as blocking and the by-pass adds cost. Mass meters are generally comparatively high in pressure drop so flow can be a problem unless a pump is used.
Purpose designed density meters such as the straight tube variety from Solartron, have a very good record for this type of application, are calibrated over a range of density values, incorporate pressure and tempetrature corrections for the sensor and allow for temperature compensation in the calculations plus they allow for other effects such as velocity of sound.
However, you may find that any flow through sensor adds cost, whatever its performancs because of valves, pumps , maintenance etc. In this case an insertion device will be preferred. This includes a range of vibrational devices from companie slike SOlartron, Hydramotion and so on.
When you do a web search for brix or density, don't forget companies such as Paar, who specialise in sugar and alcohol applications, and Cannongate who specilise in dairy and food applications.