[EricH]

There might actually be a simpler method of generating that suction, if you do indeed decide to go that route. Assuming you're already using pneumatics, replace the motor/chain with a pneumatic cylinder that will be fully retracted(or extended, depending which port you use) when suction is being applied. Ideally, you'd have a small(er)-bore cylinder pulling a large(r)-bore one with one port set vented to the atmosphere.

This method has been used before, with some success, on exercise balls. Whether it'll generate enough vacuum on totes is left as an exercise for whoever wants to experiment (I happen to not know the answer either, though I suspect it would).