Centrifuge Instrumentation
Centrifuge Instrumentation
(OP)
Hello everyone,
I am interested in instrumentation used to automate these type of centrifuges, especially in mining industry. If you have any first hand experience with them please write back. I am particularly interested in Bird's (manufacturer) centrifuges. I have found very little information on their actual design and operation. I would welcome any links, antecdotes, or personal experience.
Thanks in anticipation.
I am interested in instrumentation used to automate these type of centrifuges, especially in mining industry. If you have any first hand experience with them please write back. I am particularly interested in Bird's (manufacturer) centrifuges. I have found very little information on their actual design and operation. I would welcome any links, antecdotes, or personal experience.
Thanks in anticipation.





RE: Centrifuge Instrumentation
David Baird
mrbaird@hotmail.com
Sr Controls Engineer
EET degree.
Journeyman Electrician.
RE: Centrifuge Instrumentation
M777182
RE: Centrifuge Instrumentation
As far as the instrumentation, which parts are you looking to automate? Unless the machine is old, it should already have an automated start and stop cycle. Some companies use a UPS in the case of a power failure for a controlled stop. Oil is used for all of the bigger sizes, grease cannot be used due to the speeds being run and the need for heat disapation. The UPS would be a good idea here to turn the oil pump back on after a power failure when the machine is coasting to a stop.
A speed sensor for over speed as well as underspeed is a must. Bearing temperature sensors are good ideas, torque overload, oil pressure if oil lubricated bearings.
Mike Bensema
www.dutchmenservices.com
RE: Centrifuge Instrumentation
For some slurry streams you may need to consider density or viscosity measurement on the inlet and outlet streams. This information will help you measure the efficiency of the process.
JMW
www.viscoanalyser.com
Eng-Tips: Pro bono publico, by engineers, for engineers.
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RE: Centrifuge Instrumentation
Thanks everyone who took some time to consider my problem.
RE: Centrifuge Instrumentation
What temperature?
Any idea of viscosity at this temperature?
How do the density and viscosity of the "clean" bitumen compare with that of the untreated? and how stable are these values over time i.e. as the deposit is worked.
If you want to know how well the centrifuges are doing, then if the bitumen is of a stable consistency or shows only long term drift, then a downstream instrument is probably all you need. Laboratory data will give you the bitumens "clean" density. This, and the mean sand density lets you do a %mass display using a downstream density measurement or density and viscosity measurement.
You are already considering a nucleonics device.
However, a vibrating fork density sensor may also be suitable (upto 200degC, hence the temperature question and i am assuming you are heating to reduce the viscosity which will aid separation).
With 25% solids, I am going to ask if the viscosity shows a marked change between the solids laden and the clean bitumen. If density is insufficientlyly discriminating or you may get ambigous results, then viscosity may be a more sensitive indicator. These are questions a little bit of lab work will resolve before you have to spend any money.
The vibrating element sensors are very rugged and with good installation will give you good service.
If installed downstream of the centrifuges you will be measuring the relationship between the possible 0% solids and what you are getting. If the centrifuges are good, then presumably the sensor will not be seeing much in the way of solids anyway. These sensors are used in oil refineries and bitumen processing plant already, I just don't know of any on oil-sands.
I do know of there use in various mineral slurries inclduding chalk slurries from the extraction plant to the cement works. These slurrie sare usually well laden with extraneous material such as flints, sand and the odd bit of excavator.
I have a photo of a unit sent back for re-calibration that has evidently been hit by a large object with considerable force as well as being subject to long term erosion. The unit had been in service for some years. The sort of erosion sufered can be avoided by good installation.
These sensors are also installed in towed drones for river mud density and viscosity measurement and in downhole instrument strings. They also are used on bitumens in refinery produced bitumens for blending. Density (whatever the technology) and viscosity are popular choices for automating evaporatiors and centrifuges, sand separators, wash plant underflow monitoring and the like.
JMW
www.viscoanalyser.com
Eng-Tips: Pro bono publico, by engineers, for engineers.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Centrifuge Instrumentation
The product cents are a critical part of our process prior to rotary kiln gas fired dryers. The product is potasium cholride (potash). Tails from these is a brine solution. It would be useful if we too could improve our operating and control philosophy. It is physically difficult for us to measure any properties of the product falling into our dryers online and manual samples of the moisture are usually the only telltale of problems with the cent operation.
In your opinion would the measurement of density via the vibrating forks you have mentioned give an indication of efficiency/machine health. If so where can you get the probes? An ealry indication of screen wear or blockages would be useful.
Cheers
RE: Centrifuge Instrumentation
if you have a solution or slurry then density measurement may be suitable (or viscosity).
The main criteria is resolution required.
The greater the density diference between the carrier and the entrainment the better the resolution.
Most manufacturers offer a variety of materials including titanium, monel, hasteloy (various) and stainless and augment these with non-stick coatings such as PTFE or PFA.
I would start with www.solartronmobrey.com (7826 and 7828) but do a search (I'm getting lazy!) to find other manufacturers such as Bopp & Reuther, PEEK (ONYX i think). In flow through systems Solartron again but also the mass flow meter companies who offer density as a secondary measurement.
The Solartron fork now comes with a long stem extension for top mounting in tanks (e.g. in Boraw production).
JMW
www.viscoanalyser.com
Eng-Tips: Pro bono publico, by engineers, for engineers.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Centrifuge Instrumentation
certainly food for thought there. Your mention of mounting on a tank may be useful as the feed lines to the centrifuge don't need much of an escuse to sand out, a bit of runaway rubber lining would cause a nice blockage when introduced to a fork.
I think the feed is fairly consistant, it's the grade that changes mostly depending on the head grade to the plant and the insols level. I suppose it would be worth a try though to get the data and map the differential density overtime and then look for a meaningful relationship.
Talking of instruments for this sort of thing I recall using an ultrasonic probe that measured %solids in an ECAT thickener. I think dig some notes out.
Thanks
RE: Centrifuge Instrumentation
There is a good comment in another website on density in bauxite or aluminium production which may be relevant. I will dig it out and post it.
PS for Boraw, read Borax.
JMW
www.viscoanalyser.com
Eng-Tips: Pro bono publico, by engineers, for engineers.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Centrifuge Instrumentation
http://www.control.com/1026152447/index_html
and you may want to search that site for density as there are some good threads there.
JMW
www.viscoanalyser.com
Eng-Tips: Pro bono publico, by engineers, for engineers.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Centrifuge Instrumentation
Coriolis massflowmeters can measure massflow, density, temperature and sometimes viscosity as well.
http://www.omega.com/literature/transactions/volume4/T9904-10-MASS.html
http://www.emersonprocess.com/micromotion/
The Endress + Hauser "PROline Promass 83I" can measure viscosity as well. This means you have 4 primary variables with only one sensor.
Hope this helps,
C.