powder

[powder]

I am trying to find a range of possible solutions to fluidisation segregation during discharge and feeding into IBC's and tabletting machines, does anyone know of any reliable solutions?

 

[franky]

More information about the properties of your material, the shape of the equipment and where the segregation occur would help to provide solutions.

Could water, air or inert gas be used to improuve discharge efficency.

Is the discharge located at the bottom of the equipment?

What is the shape of the bottom? (conical,...)

Could the angle of the bottom increase if conical.

To avoid segregation the fluidisation should be improuve. Solution might involve moving nozzle location, increasing velocity in the fluid bed or change the mixing profile in the equipment.

I suggest you look for a good book on the subject I will try to found the one I used.

 

[powder]

Its a pharmaceutical company, dry bulk solid handling, so I can not use water, I just want a relatively basic tool to predict if a mixture will have the potential to segregate or not. I don't (at this stage) need to design a process that will combat the problem, just want to know in general gravitational discharge out of a hopper, (small hopper bins are ussually about 1 meter wide, conical shaped, about 1 meter tall, bottom opening approx 20cm)

any suggestions

 

[madorman]

There are a couple of parameters that determine the potential for separation during fluidization: size of particles, shape of particles and potential for static.

For most tableting processes, the powders are agglomerated prior to pressing to provide uniform distribution of actives within the incipients. Then the product is sieved to ensure a tight range of particle sizing. Pressing should be easy thereafter.

 

[quark]

Powder!

We are using PIAB make powder transfer system for our tableting machine. It's a very good system. They are of pneumatic type conveying systems and come with very precise level control systems.

Regards,

Truth: Even the hardest of the problems will have atleast one simple solution. Mine may not be one.

 

Is that pneumatic conveying dense phase? Is the connection a flexible hose, and is segregation avoidable with a relatively wide powder size distribution?

 

[quark]

keirens!

I am not quite sure with the bulk density of the material. The connection is by a pvc flexible hose and we didn't find any problems. However, both active pharmaceutical ingredients and excipients are sifted before compression. That is why we never felt any problem.

Regards,

Truth: Even the hardest of the problems will have atleast one simple solution. Mine may not be one.

 

Quark

I mean does the powder move through the hose as a condensed solid, (maybe pulsating through)or does it fly loosly throughout the hose? Because if it moves sparsely, then I think if there is a high spread of size and mass distribution in the powder mix, then pneumatic will not work for many mixtures.