Laser beam duct pressure controller system

A laser beam duct pressure controller system for maintaining a spatially uniform pressure in a flowing gas volume subjected to temporal pressure variations, wherein said flowing gas volume flows transversely from a plenum chamber into a laser beam duct in communication with said plenum chamber, and wherein some of said flowing gas volume flows from said laser beam duct into a rotatable compartment and most of said flowing gas volume flows into an exhaust duct, both of which are in communication with said laser beam duct, and also wherein said rotatable compartment has a gas volume which is to be maintained at a preselected pressure and an aperture which is exposed to an external pressure, whereby a resultant pressure gradient is introduced by changes in said pressure of said gas volume in said rotatable compartment, and thereby inducing significant undesired axial gas flow motion in said laser beam duct which can result in serious optical degradation, said laser beam duct pressure controller system comprising:

• a. a source of conditioning gas under high pressure in communication with said plenum chamber;
• b. means, interposed between and in communication with said plenum chamber and said source of conditioning gas under high pressure, for selectively allowing said conditioning gas to flow from said source thereof into said plenum chamber, whereby said gas flow feeds into said laser beam duct, and thereby a laser beam duct pressure results;
• and
• c. means, operably associated with said rotatable compartment, and with said laser beam duct, and also with said exhaust duct, for maintaining said laser beam duct gas flow pressure equal to said preselected pressure of said gas volume in said rotatable compartment, whereby said undesired axial gas flow motion in said conditioning gas in said laser beam duct is eliminated.