Appeal No. 1999-0072
Application 08/692,466
diameter branch will not receive virtually dry vapor” (column
1, lines 8 through 13). With respect to a representative
first embodiment, Stoy teaches that
the first embodiment of the subject invention 10 is
associated with a straight-through section of large
diameter pipe 12, from which a fraction of the flow
is removed through a smaller diameter branch outlet
pipe 14 extending generally perpendicular to the
straight-through section 12. A known flow
constriction 16, such as the illustrated orifice (or
a venturi not shown), is located within the smaller
diameter branch outlet pipe 14 spaced from the
junction. A sump 18 depends from the straight-
through section 12 generally opposite the opening to
the branch outlet pipe 14. A liquid bypass pipe 20
has one end connected to a takeoff point 22 located
near the bottom of the sump 18 and its other end
connected to a point 24 on the branch outlet pipe 14
downstream of the flow constriction 16. The length
and inside diameter of the liquid bypass pipe 20 are
designed such that the friction pressure drop of the
liquid flowing through the bypass pipe 20 equals the
pressure drop of the vapor flowing through the
branch outlet flow constriction 16 at [a] nominal
design vapor extraction ratio. Because the friction
pressure drop of the liquid in the bypass pipe 20
and the constriction 16 induced pressure drop of the
vapor are both [proportional] to the square of the
velocity of the flowing media, the system is self-
compensating for changes in vapor extraction ratio.
The liquid-vapor mass ratio at the exit to the
branch outlet pipe 14 remains constant in spite of
changes in extraction ratio [column 2, line 56,
through column 2, line 15].
Statler discloses a “high turndown mass flow control
system for the regulation of gas flow to a variable pressure
-4-
Page: Previous 1 2 3 4 5 6 7 8 9 Next
Last modified: November 3, 2007