I am familar with CO2 snow cleaning. In section 0006 they state "conversion of liquid CO2 into CO2 snow only takes place in a mixing chamber in which liquid CO2 is expanded into a carrier gas which is also supplied." The implication that a carrier gas is always needed. ACP nozzles require a carrier gas. Yet, in US Patent 4,806,171 Whitlock demonstrated an efective CO2 nozzle that does'nt need a carrier gas and still can remove submicron particles. Plus, that nozzle was a Lavel (asymmetric venturi) design. Does this prior art negate the claims presented here? They are doing a multi stage expansion over many steps. Whitlock just had two steps. I think the Patent office should ask them about Whitlock.
I think your quote is a bit ambiguous. Here is the full sentence:
From WO 02/075799 A1 and also from U.S. Pat. No. 7,762,869 B2, non-generic devices for generating a CO2 snow jet are known in which the phase conversion of liquid CO2 into CO2 snow only takes place in a mixing chamber, in which liquid CO2 is expanded into a carrier gas which is also supplied.
I don't read this as stating that conversion of liquid CO2 to CO2 snow only takes place with a carrier gas, as you state, but is so in the cited documents.
This isn't my field, but Whitlock is clearly relevant. However, my reading of claim 1 of US20220168762A1 shows a different nozzle configuration from Whitlock so Whitlock doesn't necessarily invalidate US20220168762A1. Based on the number of citations of Whitlock, I would highly doubt the patent examiner would overlook it when evaluating patentability of the application. Just because Whitlock doesn't use a carrier gas doesn't mean another invention couldn't.