Appeal No. 2001-1142
Application No. 09/065,143
the expansion phase of the mixture, after the mix head, and
allows for the progressive release of the blowing agent in
the reacting mass. Accordingly, the four critical factors
can be varied to achieve the desired density rather than
having to be linked to a rigid set of parameters as was the
case with prior foam processes. The speed and size of a
line or plant can be tailored to the needs of the foam
manufacturer with speeds from 1 to 5 meters per minute, and
lengths as short as 20 meters or less, rather than the more
conventional length of about 100 meters. This also permits
a smaller volume per hour of exhaust to be dealt with and
removed or scrubbed, simpler metering and plant fabrication,
foams made with CO2, a smaller volume of air to be
conditioned, and very low densities down to about 14 kg/m3
or less.
. . . . However, the pressure drop zone could be
formed from other suitably shaped pressure-drop apertures
for flowing the mixture before frothing. As is shown in
FIGS. 6 and 7, the discharge or gate bar 60 and 70,
respectively could include a series of apertures of circular
(such as the spaced apart elongated, tubular holes or
openings 74-78), oblong or rectangular shape (such as the
spaced apart slots 64-68), or a series of elongated, but
shorter, slots so long as the controlled conditions were
produced. The slot or more precisely said pressure-drop
zone 17 has a restricted cross-sectional area sufficient to
cause a pressure reduction in the mixture emerging from the
chamber 21 during frothing, and a corresponding back
pressure in the mixing device 11 for the purpose mentioned
above.
. . . .
The gate bar 60 could have the configuration shown in FIGS.
6 and 7. In FIG. 6 the bar had a rectangular outer shape as
well as a rectangular cross-sectional inner chamber 62. A
series of elongated slots, as are shown at 64, 66 and 68,
for example, could be used to provide the desired outlet
from the gate bar 60 and the desired pressure drop. In FIG.
7 the gate bar 70 is provided with a circular cross-
sectioned interior chamber 72 from which a series of tubular
5
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