Centrifugal fan can use as a pump? It can vacuum?
Yes, but it doesn't work. Vacuum pumps are generally used with liquid ring pumps and Roots pumps, and this effect can reach about 200-400Pa of the vacuum. If the vacuum requirement is higher, then there are other ways, including chemical methods.
Also, the vacuum is not low, and barely scrape together. Mainly depends on your technical requirements.
Theoretically there is no problem, as long as the entrance to fan connected to the vacuum pumping equipment you need to. But the fan draws a lower vacuum.
