Services

Refits

Refitting of conical orbiting screw-
- Mixers
- Dryers
- Coolers
- Reactors

with the AVA helix system

AVA is a leader in the field of vertical cone mixers and dryers. The AVA helical mixing system has proven itself in industrial applications and has considerable advantages over the orbiting screw system. To give the owners of existing installations with orbiting screws and internal gear a chance to upgrade without having to purchase new machines, AVA has developed a technique allowing the integration of helical agitators into existing conical screw mixer and dryer vessels.

Practical experience has demonstrated the following advantages of the modification:

• The removal of the internal gear drastically reduces repair and maintenance costs.
• Increase of the existing units’ net capacity by 30%.
• The AVA helical agitator considerably shortens mixing time.
• Process time for drying, cooling and heating is reduced by up to a factor 3.
• The helical agitator allows the use of choppers in the product area to crush agglomerates.
• The AVA helical agitator requires only one instead of two drives.
• Agitator shaft and helix can be heated for further reduction of process time.

Installation of the agitator

Orbiting screw mixers and dryers generally have vessels with dished heads welded on. The new helical agitator is therefore divided into appropriate segments and inserted through the manhole into the vessel where it is reassembled and welded. A new shaft bearing and sealing system and a new gear assembly is mounted onto the existing flange on the vessel head.

The refitting has been successfully performed on customer’s machines up to 25,000 litres capacity.

Refitting on-site generally takes 2 to 5 days, depending on the size of the machine.

Machines produced by the following manufacturers can be modified:

• Krauss Maffei
• Hosokawa Nauta
• Bolz / Summix
• All other orbiting screw machines

Experience shows that the investment for the modification pays for itself within a period of 12 to 36 months.

Trials

We would be delighted to demonstrate the advantages of the helix system at our technology centre. Machines with operational volumes between 30 and 150 litres are available.

Profit from innovative technologies

• Minimal risk of contamination
  Shaft sealing and bearings are placed outside of the product area.
• The mixing intensity can be adapted to product characteristics
  Depending on speed and design of the agitator gentle blending or intensive mixing can be achieved.
• Short mixing times
  The entire product volume takes part in the mixing process.
• Short drying times
  Permanent mixing and intensive contact between product and heated wall ensure a higher heat transfer.
• The dryer can be used as an evaporator
  Suitably designed agitators are ideal for concentrating liquids and slurries.
• Increased drying and evaporating capacities due to heated agitator
  The agitator can be heated and shaped to achieve an extremely high evaporation performance.
• Reliable and trouble-free operation
  The simple design helps to minimise maintenance costs.

Contact partner for refits:
refit(@)ava-huep.com

Download: Refitting - Conical orbital screws (PDF, 730 KB)