2-component dispenser for compressible material dosing

ViscoTec expands its portfolio with the static-dynamic mixer vipro-DUOMIX for the aerospace industry

The static-dynamic mixer vipro-DUOMIX is perfectly suited for two-component materials with very different viscosities, extreme mixing ratios and high-pressure sensitivity. The 2-component dispenser will be launched at the ILA in Berlin from April 25-29, 2018.

Technology

Like all products in the ViscoTec portfolio, the vipro-DUOMIX also relies on the technology of the endless piston principle. However, the 2-component dispenser extends the existing technology by allowing the mixing helix to rotate in both directions – without valves inside the mixing head. The dynamic mixing allows a reduction of the mixing section and the resulting back pressure by approximately one half. The individual components to be metered are dosed volumetrically into the mixing tube.

The compact design of the vipro-DUOMIX, in which both individual dispensers are arranged in parallel, makes it easy to integrate the dispenser into automated applications. Nozzle adaptation is also flexible due to the bayonet. The dosing technology specialist ViscoTec designs and constructs individual nozzles according to the customer's specifications - making use of the high fluidic know-how.

Application example: Sealing compounds based on polysulfide

Compressible materials, such as polysulfide-based sealants, present four special challenges for a dosing system:

1. To guarantee the correct mixing ratio, since pressurization can result in compression of the dosed volume in one component (usually base mass).

2. To achieve an adequate mixing quality (homogeneous mixing) at extreme mixing ratios.

3. To counteract the relaxation of the material: Due to the previous compression of the fluid (even if only minimally) a relaxation occurs after leaving the nozzle. This causes uncontrollable pressing of the dosed materials.

4. To avoid destruction of the hollow spheres contained in the fluid.

The vipro-DUOMIX is particularly suitable for compressible materials where the back pressure must be kept as low as possible. With this new development, ViscoTec offers a dosing system that provides the optimal solution:

- Flow- and counter-pressure-optimized product channels prevent fluid compression. This ensures that the mixing ratio is maintained.

- By increasing the speed of the mixing spiral, direct influence can be exerted on the mixing process. The mixing quality can thus be dynamically adjusted.

- Compression is already largely prevented by low back pressures in the system. The (residual) expansion of the material is compensated or absorbed by the possibility of rotating the filament in the opposite direction.

- The progressive cavity pump technology ensures shear-sensitive and low-pressure fluid handling. The density remains unchanged during the entire dosing process.

The correct mixing ratio, homogeneous mixing and non-destructive dosing of the hollow spheres were evaluated by the material manufacturer Chemetall using the MC-780-B material as an example and found to be good.

The vipro-DUOMIX can be used for dot dosing, bead application and potting applications. Various 2-component materials based on e.g. polyether, epoxy resin, silicone or polyurethane can be dosed.

At the ILA in Berlin you will find ViscoTec at booth 260 in hall ILA6. Convince yourself of the optimal dosage of compressible materials.