Appeal No. 1999-2775
Application No. 08/549,847
the cold gas flow is by using liquefied gas, such as liquefied
nitrogen, or a mixture of liquefied gas and compressed air
(col. 3, lines 13-22).
Peter discloses an assembly for providing a flow of cold air
(e.g., minus 40° F) to a workpiece on the bed or table of a drill
press, grinder, or milling machine (col. 3, lines 17-18), wherein
the apparatus includes a vortex tube assembly (11) having an
inlet (23) coupled to a compressed gas line (19) and an outlet
(31). According to the examiner, "Peter teaches providing cold
gas through the use of a vortex tube which produces cold gas
without moving parts or electricity, in which a filter or dryer
is used and a chiller or antifreeze injectors (col. 2, lines
5-20)" (answer, page 3). From the combined teachings of
Lubbering '242 and Peter the examiner concludes that it would
have been obvious to one of ordinary skill in the art at the time
appellants' invention was made to utilize the vortex tube type
cold gas supply apparatus of Peter as a substitute for the cold
gas supply disclosed in Lubbering '242, in order to produce cold
gas efficiently and inexpensively.
In the alternative, the examiner notes that the Vortec
Catalog teaches using a vortex tube in a cold air gun to cool
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