Ultra Centrifugal Mill ZM 300

Rotor mills are used for high-speed size reduction of soft to medium-hard as well as temperature-sensitive or fibrous materials.

THE STANDARD FOR FOOD & FEED

• Gentle high-speed pulverization due to pre- and fine grinding in one working run
• Optimum process control and reproducibility based on monitoring of the cassette temperature
• Patented cassette system for maximum sample recovery and easy cleaning
• Optional cassette for sample volumes up to 600 ml
• Wide speed range from 6,000 to 23,000 rpm
• Defined final fineness due to ring sieves with aperture sizes from 0.08 – 10 mm
• Collecting vessels for sample volumes from 250 ml to 4.5 l
• Automated vibratory feeder and various cyclone systems available

INCREASED REPRODUCIBILITY THROUGH TEMPERATURE MONITORING

The speed range from 6000 to 23000 rpm allows for optimum adaptation of the grinding process to the sample requirements by keeping the grinding time as short as possible and the temperature increase as moderate as possible. Too much heat may have a negative effect on the grinding results, for example, if moisture or volatile components escape.

The ZM 300 is equipped with an integrated temperature sensor which measures the temperature of the cassette lid near the ring sieve. The measured temperature is constantly shown in the mill’s display, allowing the user to optimize the grinding process and improve reproducibility.

MAXIMUM SPEED FOR HIGH FINAL FINENESS AND INCREASED THROUGHPUT

The maximum speed of classic centrifugal mills, like the widely used ZM 200, is usually limited to 18,000 rpm (rotor peripheral speed 98 m/s). The ZM 300 achieves a maximum speed of 23,000 rpm (rotor peripheral speed 118 m/s) and produces particles which are 15 to 20 % finer in comparison, depending on the material.

The higher speed has a particularly positive impact on the grind sizes of polymer samples which are pulverized cryogenically, or of fibrous materials like hay. Compared to models with a maximum speed of 18,000 rpm, the throughput may be increased by 10 to 15 %.

APPLICATION EXAMPLES

Grind sizes of plastic materials (POM or PP) after grinding with different sieves and speeds. The speed of 23,000 rpm results in a higher fineness for all sieves compared to grinding at 18,000 rpm. For example, a 19 % reduction in fineness can be achieved when POM is ground with a 0.12 mm distance sieve at 23,000 rpm.

The maximum sample throughput, e.g. when crushing chicken feed with a 0.5 mm ring sieve, could be increased by 16% when crushing at maximum speed of 23,000 min-1 instead of 18,000 min-1.

REDUCING THE FINE FRACTION

The fines content in a pulverized sample can be controlled by speed reduction. If, for example, the grains of an animal feed sample are to be coarsely ground to avoid dust formation, a reduction to 6,000 - 10,000 rpm will provide the desired result.

Thanks to the variable speed, the ZM 300 can be flexibly adapted to all requirements in the food and feed industry, chemical industry, and in agriculture.

CRYOGENIC GRINDING

Cryogenic or cold grinding is the ideal solution for pulverizing samples that cannot be reduced to the required fineness at room temperature. This procedure involves the use of grinding aids such as liquid nitrogen (-196 °C, embrittlement of the sample outside the mill) or dry ice (-78 °C, sample/dry ice mixture) to embrittle the sample material by cooling, and thus improve the breaking behavior.

In addition, highly volatile components are better preserved in the sample by cooling. Cryogenic grinding is easy to perform with the ZM 300 and is recommended especially for plastics or very temperature-sensitive samples. The video shows the process with the predecessor model ZM 200, which is identical in the ZM 300.

IDEAL FOR LIGHT & HEAT-SENSITIVE MATERIALS

When operated with the optional cyclone-suction-combination, the ZM 300 is also suitable for grinding low-density or heat-sensitive sample materials.

• Efficient cooling of sample and grinding tools
• Improved sample discharge from the grinding chamber
• Particularly suitable for large volumes
• The cyclone accommodates sample bottles of 0.25, 3 and 5 liters
• Ideal for cryogenic grinding

CONVENIENT OPERATION AND EASY CLEANING

The ZM 300 is easy and safe to operate. The large touch display with rotary knob permits convenient entry of the grinding parameters. It shows the current cassette temperature and load during grinding which helps to prevent overloads by feeding the sample too quickly.

TYPICAL SAMPLE MATERIALS

The versatile Ultra Centrifugal Mill ZM 300 processes materials such as bones, cereals, chemical products, coal, coffee beans, collagen, corn, dried fruit and vegetables, dried larvae, drugs, electronic components, feed pellets, fertilizers, food, grain, graphite, minerals, paper, pharmaceutical materials, plant materials, polymers, powder coatings, rice, rubber, seeds, spices, straw, sweets, textiles, tobacco, waste, wood

TECHNICAL DATA

FUNCTIONAL PRINCIPLE