The MM 500 control is a high energy laboratory ball mill that can be used for dry, wet and cryogenic grinding with a frequency of up to 30 Hz. It is the first mixer mill in the market that allows to monitor and control the temperature of a grinding process.
The temperature area covers a range from -100 to 100 °C. For maximum flexibility, the mill can be operated with various thermal fluids, enabling the use of different tempering devices for cooling or heating. If liquid nitrogen is chosen for cooling, the mill needs to be equipped with the optionally available extension device cryoPad. The innovative cryoPad technology allows to select and control a specific cooling temperature in the range from - 100 to 0 °C for the grinding process.
The cooling and heating of the sample material is realized with the patented concept of thermal plates, making sample cooling with, e. g., open liquid nitrogen baths or dry ice obsolete. For tempering, the grinding jars are simply placed on top of the thermal plates. When the grinding jars come in contact with the thermal plates, heat is effectively transferred from or to the jars via the tempering device. The patented hermetically sealed fluid design allows to operate the mill with different thermal fluids, ensuring a flexible and safe temperature regulation and requiring only minimal effort for the user. Depending on the operational setup that is built up, the temperature of the thermal plates can be set in the range from - 100 to + 100 °C.
To control the temperature of a grinding process, the mill needs to be connected to an external tempering device. Basically, there are two options:
1. Temperature regulation with liquid nitrogen
The mill is operated with liquid nitrogen and connected to a nitrogen tank. In this setup the mill must be extended with the optionally available extension device cryoPad. The patented PID (proportional–integral–derivative) system of the cryoPad controls the flow of liquid nitrogen and herewith the temperature of the thermal plates. In this setup, it is possible to select and maintain the temperature of the thermal plates at a specific value. The desired temperature is adjusted via the touch display and can be selected within a range from - 100 to 0 °C, in steps of 10.
Setup 1: Extension device cryoPad and LN2 tank for the operation with liquid nitrogen.
2. Cooling or heating with a liquid thermal fluid
In this setup, the mill can either be connected to a cryostat, to a chiller or to the water tap. The external tempering device regulates the corresponding thermal fluid to a defined temperature and the thermal fluid transfers this temperature to the thermal plates. As during a grinding process, a significant amount of heat may also develop inside the jar, the temperature of the thermal plates may be manipulated. To sum up, the actual temperature of the thermal plates depends on both, on the temperature of the thermal fluid and on grinding parameters, like frequency, time, jar volume, size of grinding balls. For a maximum control of the grinding process, the actual temperature of the thermal plates is continuously monitored in the touch display.
Setup 2: Operation with an external tempering device; e.g. water tap, chiller or thermostat.
