Using Yokeş® Powermill Convecta® / G – Conventional Bead Mill with Dynamic Gap Seperator in Wet Grinding of High Viscosity Products

The working principle of Horizontal Wet Grinding Machines (beadmill) in its simplest form is; while the product that is pumped into the grinding chamber enters from one side of the chamber and moves towards the exit,, the solid material in the liquid product are crushed by the impact/hammering effect created by the beads and the particle size is reduced to be suspended in the liquid.

We call the system that allows the dispersed product to come out of the grinding chamber and keept the grinding beads inside at the end of the process as, seperation system.

Several different separation systems are used in Horizontal Type Wet Grinding Machines . Although it is the oldest application among them, the most efficient for some products, especially those with high viscosity, is the Dynamic GAP Separation System. This system consists of two separators located at the outlet of the grinding chamber and working with Rotor-Stator motion.

In this system, where the GAP distance can be adjusted very precisely (+/-0.1mm), it can be ensured that the beads remain in the grinding chamber while the grinded product passes through the separators.

The separators are made of “Sintered Carbide” materials and are designed to be highly resistant to intense zirconium beads’ friction.

Although simpler solutions have been found in separation systems over time due to the high mechanical precision required, these solutions cannot provide the flow rate and problem-freeness provided by GAP Separators in every product, especially in high viscosity.

The Sieve Type separation system used in High Flow Bead Mills gives very efficient results in most wet grinding processes. However, especially when grinding Flexo / Rotogravure Printing Inks and similar high-viscosity products, dynamic GAP separators work much more smoothly.

In sieve systems, when the moment provided by the agitator shaft to the grinding beads is less than the resistance caused by the high viscosity, the beads lose their ability to move independently and can be piled up to the outlet as a whole with the product, which may cause clogging of the sieve responsible for providing separation and interrupting the process.

At this very point, as Yokeş® Makina, we offer Powermill Convecta® / G – Conventional Horizontal Type Bead Mill / Wet Grinding machines with rotor/stator working Dynamic GAP Separation System as a solution.

Powermill Convecta® / G is the most advanced model of the initial “Convectional Agitator Bead Mill” with Dynamic GAP Seperation, which Yokeş® has been manufacturing for over 25 years. Powermill Series Bead Mills have already started their process life with Dynamic GAP Seperation System, when they were initially designed in 1998.

Although we have many more Bead Mill models with more advanced sieve seperation systems today, Dynamic GAP Seperation system is still indispensable for us, due to their highly reliable seperation capability especially when dealing with high / ultra high viscosity
products.

Tungsten Carbide GAP Seperators of the mill have a rotor-stator action, which prevents blockage at the mill outlet and forces the machine to be able run nonstop, 7/24.

The efficiency of the machine is determined by the energy input to the grinding chamber and the optimal exploitation of this energy for the grinding process.

Thanks to its optimal grinding chamber geometry, powerful design of the agitator disc and special separation system, Powermill Convecta® / G mills achieves a high degree of efficiency.

Features:

• The grinding chamber has an optimal length/ diameter ratio. Specially designed shapes of the agitator discs guarantees the most energy efficient use and prevents compaction of the grinding beads.

• Cooling jacket of the grinding chamber is designed to maximize the heat transfer from the product to the cooling water system.

• Shape and number of the agitator discs can easily be adapted to the product to be processed.

• All types of grinding beads (min. 0,6mm) can reliably be used in the machine, thanks to the special design of the grinding chamber and the Dynamic Seperation System. Ultra fine grinding values can be achieved with Powermill Convecta® / G.

• All the machine parts that are used inside the grinding chamber are manufactured from upmost quality materials to resist against the aggressive grinding effect of the zirconium beads.

According to the product to be processed, specific hardened steels, zirconium oxide, silicon carbide and special stainless steel materials, etc. are used.

• Shaft sealing is done by a reliable cartridge type double mechanical seal. Maintenance or
changing of the seal are very easy and can be handeled by the machine operator.

Rinsing of the mechanical seal is controlled by a closed circuit rinsing system, which is also water cooled. Mechanical seals of Powermill Convecta® / G mills have a long lifetime.

• Variable feeding pump speed control system is also controlled by a with frequency converter. Diaphgram type air pumps and monopumps are used for high viscosity products.

• All process parameters can be observed, adjusted and be interfered by the machine operator by means of the sophisticated PLC control system. Main shaft is driven by Variable Speed Control System with frequency converter.

With this feature, most efficient milling results can be achieved. Also, rinsing and cleaning of the machine can be done easily at low rpm values.

• Easy opening rail system of the grinding chamber provides easy and detailed cleaning – maintenance of the grinding chamber components.

Because, “High viscosity was never an issue for us….”

Onur Ovalı
Sales & Marketing Manager
Yokeş Makina