cane sugar dosing

V

Thread Starter

vivaracho

we are trying to automate the sugar cane dosing from feeding tables to main conveyor in our sugar mill, now we are using ultrasonic level transmitters, without good results, so we are looking for other ways to do it, can anybody help me with some bright idea?
 
J

john pietila

Have you considered conductivity electrodes (insulated 'buttons' )in the feed chute? This works well in Australia.

Regards
John Pietila
brisbane Australia
61 7 3849 8118
[email protected]
 
A

Adolfo Jimmy Saldivias

Alejandro:
We are implementing just the same project here in Bolivia. You can contact
me off list if you want (specially if you want a more extensive spanish
explanation). Of course you can allways phone me too.
Question:
Where are you measuring the level with the ultrasonic? If you are doing so
in the Chute Donnelly, you will need to make several modifications to the
chute in order to measure.
If you are doing the ultrasonic measuremente after the cane choppers, I mean
over the band, this is the best place to to it.
If you are doing the measurement of level before the cane choppers, that is
a mistake. Since the heigh of the sugar cane BEFORE the cane choppers is not
a good parameter to know the real amount of cane.
For example if the cane you are receiving from suppliers is an entire stick,
it will have a greater height but less cane (I mean mass).
If the cane comes from suppliers who use harvesting equipment, it will come
in small pieces approximately 7 inches long. This small pieces will have a
lower height but will have more cane (again I mean mass).
The real measurement that you will have to do is a WEIGHT measurement on the
feeding tables. So you can decide how many TONS PER HOUR you want to send to
the mills.
In order to do this you have 2 choices: the difficult one and the simple
one.
The difficult one consists in cutting the supporting legs for all the
feeding tables and installing load cells on each one.
The easy one is NOT to cut the supporting legs and instead use a MICROCELL,
manufactured by Kistler Morse, an american company. These microcells can be
installed without stopping the process, and have enough accuracy for your
application.
And then when you have your weighting devices installed you will need an
extra measurement, named the speed of the feeder.
For this you can use either an encoder or a magnetic pick up.
With both data, weight and speed, you have a measure to compare with the
setpoint of control that you want to reach, and you can control the speed of
the feeder.
Finally you will need the controller. A loop controller for this matter.
I hope this helps.
This system works like a charm.
By the way, do not forget to visit our website (address below), you may find
interesting information: "all you wanted to know about control and
instrumentation, but were afraid to ask".
Regards,

MBA Ing. Jimmy Saldivias
TECSIM
Phone: 591-4-523438
Fax: 591-4-523413
http://tecsim.trading.net
 
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