Can I connect the output of a Vortex Tube to an Air Knife?
No, for proper operation, the Vortex Tube cold outlet should not be subjected to any restrictions that would produce backpressure in excess of 5 PSIG. An Air Knife would restrict the flow of a Vortex Tube to the point where the backpressure is excessive and severely limit the cooling capacity of the Vortex Tube. The design of the air knife is to entrain large amounts of ambient air and add it to the airstream reaching your parts. The dilution of 1 part of cold air mixed with 30-40 parts of ambient temperature air will result in air temperatures reaching your part to be not much different than ambient temperature.