If testing is carried out according to GMP standards, stricter standards must be set for all directions of the centrifuge. According to the requirements of the "Good Manufacturing Practice for Pharmaceutical Products" for equipment, pharmaceutical centrifuges must not only achieve separation characteristics, but also meet the requirements for equipment in the "Good Manufacturing Practice for Pharmaceutical Products". The surface of the centrifuge that comes into direct contact with the medicine should be smooth, flat, without dead corners, and easy to clean.
There are multiple cleaning heads or cleaning pipes in the inner cavity of industrial centrifuges, which can be cleaned without opening the lid or running the centrifuge. The focus is on cleaning the bottom of the drum and bearing seat, the liquid blocking surface and outer surface of the drum, the inner surface of the drum, the inner surface of the flip plate and feeding, the surface of the scraper and other devices, and the inner surface of the casing.
In general, the pharmaceutical industry should choose stainless steel structures. Although some external parts do not directly contact the material, they are still suitable for stainless steel for cleaning the surface and maintaining a clean workshop environment. Select suitable materials such as stainless steel, plastic lining, polytetrafluoroethylene, titanium, etc. according to the corrosion data, chemical properties, temperature and concentration of the separated substance. The surface of the industrial centrifuge should be flat, smoothly transitioned, and eliminate dead angles, liquid accumulation, material accumulation and other dead corners in the structural design and manufacturing to ensure hygiene.
The pneumatic components of industrial centrifuge technology, such as pneumatic scrapers, gas-assisted scrapers, and gas recoil devices, are powered by gas, compressed air, or compressed nitrogen gas, and the air source needs to be purified. This ensures that drugs are not contaminated by impurities in the gas. If used in explosion-proof areas, the air source should be nitrogen gas.
In the industrial centrifuge technology commonly used in the pharmaceutical industry, the discharge centrifuge, manual top-discharge centrifuge, or bag-lifting centrifuge are common models. The filter bag is lifted each time the material is discharged, making it easier to clean the residual filter cakes and regenerate the filter cloth. The filter cloth is installed on the wall of the drum, so it is more difficult to disassemble and install than the discharge centrifuge. There is a safe distance between the scraper and the filter cloth to prevent the scraper from damaging the filter cloth. The presence of this residual filter cake layer is not a problem for general chemical products.
However, in the pharmaceutical industry, the presence of residual filter cakes cannot meet the requirements for eliminating contamination between batches. To clean up the residual filter cakes, a gas-assisted scraper is installed on the scraper, and a gas recoil washing nozzle is installed outside the drum filter hole. During scraping, high-pressure gas passes through the drum filter hole from the outside to the inside, impacting the filter cloth and residual filter cake layer to make the filter cloth produce pulse oscillation and move inward, thus making the filter cloth close to the scraper with flexible pushing force and reducing the thickness of residual filter cake layer. At the same time, the high-pressure gas ejected by the gas recoil-assisted scraper blows away the residual filter cake on the filter cloth. This device can effectively reduce or eliminate residual filter cakes. At the same time, the filter cloth also has a certain degree of regeneration, and cleaning of the residual filter cakes for some materials with small particle size or high viscosity can eliminate residual filter cakes in the next filtration.