Appeal No. 97-0742
Application 08/427,775
Ecker discloses a heat pump system designed to prevent
freeze-up of the outdoor heat exchanger typically found in such
systems. As explained by Ecker,
the temperature of the boiling refrigerant brings the
temperature of the heat exchanger coils below the dew
point of the ambient air so that moisture condenses on
the coils. Further decrease in the temperature below
the freezing point then freezes the condensed moisture,
forming ice. The ice builds up and eventually
completely blocks the flow of air through the heat
exchanger [column 1, lines 36 through 43].
Ecker’s solution to this problem is to dispose the outdoor heat
exchanger in a heat exchange fluid circuit which warms the heat
exchanger until its temperature is above the dew point of the
ambient air (see, for example, column 8, lines 11 through 32).
According to the examiner,
[i]n view of the teaching of Ecker, it would have been
obvious to one of ordinary skill in the art at the time
the invention was made to provide the web printing
machine of Mitter with heated fluid circulated to any
structural parts of the printing machine that is [sic,
are] exposed to a warmer ambient air so as to prevent
condensation of moisture from occurring [answer, page
4].
The combined teachings of Mitter and Ecker, however, do not
justify the examiner’s conclusion of obviousness. Ecker’s
solution to the problem of condensation freeze-up on an outdoor
heat pump component has little, if any, relevance to the textile
web printing apparatus disclosed by Mitter. Although Mitter is
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