In the paddle screw cooler, granules or powders are cooled down to -196°C by liquid nitrogen. This cooler type is normally used for cold grinding processes. Here, tough, elastic or temperature sensitive materials such as thermoplastics, elastomers, spices, pharmaceutical products or waxes can be cooled. Coolers are available with capacities from about 50 to 3000 kg per hour.
Cryogenic Control Valve Unit for Liquid Nitrogen
In a cryogenic control valve unit, the dosage of liquid nitrogen is regulated in accordance with a 4-20 mA signal. A control valve is mounted on a stainless steel frame, together with safety valves, manometers, a dirt trap and an evaporator coil for captive medium supply. If required, it can also be supplied with a solenoid or membrane valve as an open/close valve. The unit is also available in a stainless steel cabinet with a viewing window.
PID controllers are required for the control of a cold grinding plant. They supply the output signal needed for the control valve unit. The regulators are preset for direct use.