Electromagnetic Stirrer

Re:Help on electromagnetic stirrer :-I work in a printing industry and we generate alot of ink waste for processing before discharging.Hence we have large collection tanks of about five thousand litres capacity to store the waste prior to processing,as a result,the contents need to constantly agitated to avoid coagulation.The original design of the processing tanks came with motorised stirrers but these did perform long before they started giving us problems may be due to the volume.We decided to convert the stirrer to air agitation and this has solved our problem for quite some time now without problems,may be you could try it.

Air agitation is a very good idea. yusufgwani. I actually thought of that.

Any idea on how to do it. Is there any makers for air agitation device out there?

Since you have done it, you can really save some precious time for me. Can you pls provide some links for me to start from?

Thanks a lot. Really appreciate your help.

In a previous career I did a fair amount of chemical analysis on liquids. We used a magnetic stirring system, in which an encapsulated bar magnet is placed in the bottom of a non-magnetic container. The container is placed on a stir table, which produces a rotating magnetic field of controllable speed. The bar magnet follows the rotating field, stirring the liquid. Here's an example of a home-made version used in beer-making.

For a ready-made unit, there are several vendors listed on Globalspec. Search for "magnetic stirrer".

Thank you for your reply pwr2thepeople. I thought of the idea of encapsulating a magnetic bar to the tank. My tank is shaped in such a way that it is semi-sphere at the bottom. And I believe in order for me to get a good rotation of the magnetic bar is by enveloping the tank with a stator to provide the magnetic field. I could not find any supplier out there that have this stator.

Do you have any contacts for this. I do want to give it a try. I am trying to source for a cheapest solution out there.

Thanks again.

It appears you could use an off-the-shelf AC induction motor. To go low-cost, try to find a used 3-phase induction motor with a center bore big enough to fit your tank. You wouldn't need the rotor, bearings or endbells, just the stator itself. If you can find a motor rewind shop in the area, they may have, or know where to find, just what you need. Many techs enjoy a challenge as much as engineers!

Stand the motor stator vertically & set your tank in the middle of the stator. Connect the stator to an AC source, with a high-wattage resistor in series with each winding. This will provide a constant mixing speed. To control the speed, connect a small VFD (Leeson or similar) to adjust the input frequency.

Have you considered ultrasonic (piezoelectric) agitation of spray head?

I did consider that Bill. Ultrasonic, I believe will do the job quite well.

Only 1 problem:

1. Cost - I heard it is expensive. Could not find any supplier for this yet. Can I get some help on this.

http://www.humidifirst.com

Piezoelectronic print heads were developed years ago when the industry got away from dot matrix pin printers and inked ribbons. These were used on liquid ink printers as well as some dry type toner printers, including laser printers.

This company, for one, has developed actuators for such use. Google (I use the search engine, Ask.com a lot) piezoelectric.

Is this a large tank? We have 2 machines here that need to keep solids suspended in water prior to application. One of them uses a magnetic stirrer as discussed previously, the other holds the tank at an angle & keeps the tank rotating, the take off and return pipes are held so that they pass through the neck down the centre of rotation. Both work equally well.

Hi Nigh,

Your idea seems to be what I am looking for. I can't really picture the 2nd idea where the tank is being rotated before the the solids are passed through. Is it possible for you to give some sketch of this, hope not troubling you.

You can even mail the sketch to thayabaran@agni-inc.com.

Thanks again Nigh. Really appreciate you help.

Look into lapping supply companies, Engis is a good start

if you are trying to separate ( separate out) carbon particle don't use magnetic stirrer due to carbon and its impurity magnetic principal carbon particle and attract to wards it and its waight increase result capsule of magnet stop rotating,

simply use point vibrator If need give some bend just like cam to it and operate it with your existing needle pin dense particle are separated by vibrator and choke problem solved.

( magnetic stirrer are used commonly in lab. milk dairy ext. )

It sounds to me you are talking about an electromagnetic stirring system. These devices have no moving parts, but create a rotating magnetic field. You can see examples here and here.

Bill Morrow

< believe, if I could maintain the carbon ink uniformly stirred in the tank before spray, I might be able to prevent the choking of carbon in the valve. Therefore, I am trying to build a electromagnetic stirrer to keep the carbon ink stirred all the time.

Let us follow your Belief:

You want to keep Stirring?

So stir with a Laboratory Stirrer. All kinds/sizes of variable-speed stirrers available inMarket. A tiny motor(sometimes Geared-motor) keeps agitating.

If not good enough--you can bubble air/gas to keep stirring.

One of the issues with obtaining a stable dispersion of carbon in water (or other liquids) is the particle size of the carbon. I have never dealt with inks, but remember preparing carbon slurries for use in production of black nylon moulding powders years ago. At that time, we used homogenization equipment (from the milk processing industry) to provide carbon black solutions of <1 micron size (typically). Perhaps if the ink were prepared in such a manner the use of lab scale stirrers would be able to maintain a stable dispersion.