Appeal No. 1997-0287
Application 08/263,034
any knowledge within the level of ordinary skill in the art.
Accordingly, the rejection of claim 11 over Andres and either
Swearingen '689 or Swearingen '768 is reversed.
Andres and Miura
Miura discloses a turbo compressor having an axial thrust
balancing mechanism comprising a passage 29 between a
balancing chamber 33 and the suction nozzle inlet 24, a
control valve 30 in the passage, and a controller comprising
the circuitry in figure 1, which is responsive to an axial
displacement signal from the position detector sensor 34 to
regulate the control valve. Miura discloses that the turbo
compressor uses an active magnetic thrust bearing 28 which is
also controlled by the axial position detector sensor 34.
Miura states (col. 8, lines 15-33):
In accordance with this embodiment, this control
operation is consecutively repeated to prevent occurrence
of a large thrust force acting on the thrust bearing even
if the operation conditions are changed. Thus, the
thrust force produced to act on the rotor can be
controlled through the steady and transient operations so
as to be prevented from being excessively increased,
whereby the size of magnetic thrust bearing 28 can be
reduced. If the size of the magnetic thrust bearing can
be reduced, a reduction in the rotating mass outside the
journal magnetic bearing 27 as well as a reduction in the
axial length of the shaft can be achieved, thereby
facilitating supporting a turbo compressor by means of a
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