Vacuum subsystem

Lockout stations – airlocks – cleanroomlocks

Lockout stations may be situated well along the transport tracks.

• Many on the slow side before "track fusion" or
• Few on the fast side after the "track fusion"

It should be quite easy to factor the vacuum system apart from the other systems.

• Lock-out can be done without letting single molecule of stray gas in.
• Lock-in not so much. See: Vacuum lockout

There might be a deeper physical reason behind this asymmetry relating to entropy ...

To implement a zero backflow vacuum lockout there
is a need for a bit of robotics for doing the following operations:

• Take off the inbound track put into the lock
• Take out of the lock put onto the outbound track

Lock-out for parts of arbitrary shape in is not possible without some stray gas moving in. To get rid of it a combination of pumping and "getter grids" would be the natural choice.

(TODO: Investigate if staged airlocks at the same assmbly level interlayer are of benefit.)

Positive displacement pumps

• The lockout-stations / airlocks are essentially atomically tight positive displacement pumps.
• Zero backflow vacuum lockout stations are a special case.

There are even continuous rotative motion positive displacement pumps:
progressive cavity pumps but their nontrivial geometry calls for slightly larger sizes
and computational optimization of atom placements. (As in the case of evolvent gears and kaehler brackets)

Nanoscale turbomolecular pumps

They sould work. (wiki-TODO: Reference Nanosystems section on that topic.)

Getter grids & refreshment

High surface area parts with many open unsaturated highly reactive bonds.
Cryogenic capture is only useful for much larger scales so not really an option unless everything is cooled as a whole.

After nominal usage time or somehow detected bad state these could be

• either disposed as a whole
• or a refresh could be attempted

A refresh faces similar problems to atomically precise disassembly.

Getter grids could be located

• in spaced between staged airlocks
• along the molecular mill assembly lines.
  

There needs to be some infrastructure for their management.
They'll likel will hold out a long long time (they may not even be necessay when no reverse flow lock-ins are done).
So they could be replaced in the course of a reassembly of the whole gem-gum factory.

Related

• Up: Subsystems of gem-gum factories
• Vacuum lockout
• Cleanroom locks