How a Hammer Mill Fulfills the Quality Demand of a Pharmaceutical Company

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DÜPERTHAL Sicherheitstechnik GmbH & Co. KG

It became clear after the first few tests that the Hammerwitt-3 was best suited to fulfill these requirements. At first, the feed hopper of the hammer mill was modified in order to be able to cool the product load with liquid nitrogen to the target temperature. An inlet plug for a 1 l container was used for gassing with nitrogen. The grinding chamber was executed with Atex II 1G/D (Zone 0/20) conformity, and mounted under the Conidur perforated plate with two temperature probes, in order to measure the screen temperature and control and hold it stable by the PLC.

In addition, a time measurement instrument was built into the drive unit in order to ensure that the run time remained the same. An important factor for temperature control is a fan with a pressure sensor to control air volumes. A filter and de-dusting ProFi-Clean 90 system was mounted at the connection to the air supply of the building.

A cylindrical 3 l product container was installed at the outlet as a further customer-specific product. Furthermore, Debiopharm did not want to mount the electronic switchbox on the hammer mill housing, but rather to connect it by cable to the machine in order to be able to use this with a wall-mounted system.

Process Display

It is important for the user to be able to intervene in the process, if needed. Several means are available to achieve this: A mill speed display (measured on the shaft), the actual current value of the motor and the motor starting time. RPM can be set using a potentiometer. The mill is automatically stopped if there is a fault.

Additional Information

Facts and figures of the hammer mill

The Hammerwitt mills of Frewitt are suitable for fine milling and pulverization of hard, crystalline, and fibrous products to fineness of up to 30 µm. It is used for laboratory applications and small batch production in GMP and High Containment.

Hammerwitt-3: The outputs achieved with this mill can be upscaled to those of the industrial hammer mills. An advantage of the mill is it´s high flexibility thanks to the interchangeability with a Coniwitt-150/200 conical sieve mill head. This means two milling processes on one machine. Particle size range from 1 cm to 20 µm; Throughput up to 700 kg/h; Density of 2 kg/dm³

Hammerwitt-6/Hammerwitt-15: High rotor speeds are largely responsible for the immediate size reduction of the product at high throughput. The rotor can be reversed without any difficulties, enabling products to be crushed via reproduction in size by the hammers (impact side) or by the knives (cutting side). The rotor drive is ensured by a single bearing so that the product is heated to a minimum during the process.

Hammerwitt-6: Particle size range from 2 cm to 30 µm; Throughput up to 2000 kg/h; Density up to 2 kg/dm³

Hammerwitt-15: Particle size range from 2 cm to 30 mm; Throughput up to 5000 kg/h; Density up to 2 kg/dm³

Filter System

The ProFi-Clean 90 filter system is a module that ensures that there is no overpressure in the discharge hopper, and thus the product always flows out of the mill chamber at the same rate. The suction system valve is activated (using a venturi effect) as soon as the mill motor runs and remains in this state, until it stops. The filter is cleaned with a one-second impulse at least every three minutes.

* Herzog is sales manager, Frewitt Fabrique des machines SA, Granges-Paccot/Switzerland;

(ID:42581689)

Milling Process

How a Hammer Mill Fulfills the Quality Demand of a Pharmaceutical Company

Process Display

Filter System