Thats how @anon42519203 was doing his, mabey he can chime in.
Once cfm flow is gone molecular flow comes into play, the name of the game is pushing molicules tward the mechanical pump and out of the system. Diffusion and turbomolecular pumps are used in UHV systems specifically for this purpose. An array of mechanical vacuum pumps may work in a slightly similar way, but not as effectivly as the turbo or diff pumps.
https://www.pfeiffer-vacuum.com/en/know-how/introduction-to-vacuum-technology/fundamentals/types-of-flow/
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