# Thread: Vacuum Transporting of Chocolate Flakes

1. Dmitry Guest

## Vacuum transporting of chocolate flakes

Dear sirs
Can any one advise me the best way to convey chocolate deflash flakes at temperature 16-18 degrees Celsius (size of particles 2-8 mm). Now we use vaccuum transport for that purpose.
We have problems with build up in elbows. We got two 90 degrees elbows. The entire line length is 10 meters.
Can you give some recommendations on this product conveying problem?

Dmitry

2. Dennis Hauch - Freeport, TX, USA Guest

## Chocolate Build Up

Dmitry,

Your thread did not state it but I’m thinking that the two 90 degree elbows that you are now using are long radius sweeps, the bend radius being equal to 10D or something like that.

A sweep causes the product to slide along the wall, the larger the bend radius the longer the sliding contact is maintained which, in your case, is likely causing the chocolate to melt slightly and create the build up that you mentioned.

Coperion-Waeschle offers a special bend for products that are susceptible to degradation called a Gamma Bend. It is designed to provide a single particle-to-particle impact, and that occurs under reduced-velocity conditions. My personal experience with these has been very good.

Regards,

Dennis Hauch

3. Long radius bend is a good solution, have you thought of using rubber bends? I have read a report on conveying of milk powder in a positive pressure system. The build problem was solved by using a rubber pipe. The theory was as the build up occurred at a point the rubber pipe expands and the material peels of from its surface. Of course the other advantage is the soft surface of rubber on which material tends to bounce off and the build up is less in the first place. I think if find the right food grade rubber pipe it should work equally well for a negative pressure system.

The other thing I would recommend is to keep the conveying velocity as low as possible. Recently work carried out at Wolfson Centre on granulated sugar showed the material build up in vacuum system to be exponentially related to conveying velocity.