Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02031293 1999-09-14
METHOD OF FILLING ELONGATED CFIANNELS WITH RESIN FOAM
BACKGROUND OF THE INVENTION
Several structural applications require filling of
relatively small cross-sectional area elongated channels
with foam, preferably a multi-component foam, such as
polyurethane. The purposes of the foam "core" includes,
for example, providing a thermal barrier, sound
attenuation, improved structural rigidity and impeding air
infiltration. The method of this invention is
particularly adapted to a commercial mass production
method of substantially completely filling such elongated
channels, while reducing labor costs.
The method of this invention will be described in
relation to tree filling of the channels of an extruded
lineal, such as used by the window and sliding door
industry. It will be understood, however, that the method
of this invention is also suitable for many other
applications which require filling of relatively small
cross-sectional area elongated channels with resin foam.
Extruded linea:Ls used by the window industry, for example,
are generally formed of polyvinyl chloride (PVC). The
extruded lineals are commercially available in 14-foot
lengths or longer and generally include two or more
parallel channels. The channels to be filled have a
cross-sectional area ranging from about 0.5 square inches
to 2 square inches, or greater. The channels may be
filled with a relatively rigid polyurethane foam to
improve the structural rigidity of the relatively flexible
PVC lineals, impede air infiltration and to provide a
thermal barrier and reduce sound attenuation. It is
generally difficult to use a pre-formed foam core because
the shape of t:he channels may be complex, and the shape
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varies from channel to channel. Pre-formed or pre-cut
foam cores have, however, been used in such applications,
where the foam core is cut to the desired shape and then
telescopically inserted into the channel.
The need therefore remains for a method of
efficiently filling an elongated channel, such as the
channels of an elongated lineal, which eliminates or
substantially eliminates voids and which preferably
requires only one operator. In the method of the present
invention, elongated channels, such as the channels of
extruded lineals, may be filled with foam, including
polyurethane foam, by one operator, substantially
eliminating voids in the foam core . The elongated channel
may be filled i=rom one end and takes only a few seconds to
complete. The method of this invention does not require
fixtures or gun extensions, such as a tube or probe, and
the method is not very sensitive to operator control
SUMMARY OF THE INVENTION
As described, the method of filling elongated
channels of this invention requires only one operator and
substantially eliminates the problem of voids. Thus, the
resultant foam-filled channel provides the advantages
sought by the application, including potential improvement
in structural rigidity, particularly for relatively
flexible channels, and other advantages, including sound
attenuation. The foam core further impedes air
infiltration a:nd provides a thermal barrier.
The method of this invention first includes orienting
the elongated channel in an upwardly angled orientation,
preferably at an angle of greater than 30 degrees and less
than 90 degr~=_es relative to horizontal. The most
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preferable angle is about 60 degrees. Where the channel
is open at both ends, such as the channels of an extruded
lineal, the Lower end of the channel is temporarily
sealed, which may be accomplished by applying tape over
the lower open end. Where the lineals are received in a
cardboard box, for example, the lineals resting against
the lower end of the box may be sufficient to temporarily
seal the channels. The method then includes directing a
thin, relatively high-pressure high-velocity stream of
liquid foamable resin into the open end of the elongated
channel, preferably parallel to the inside walls of the
channel. The :high-pressure and high-velocity carries the
liquid foamable resin stream at least partially down the
length of the elongated channel, prior to contacting the
inside walls c>f the channel, to prevent creaming of the
liquid foam on the inside walls, blocking the filling of
the channel. In the most preferred method of this
invention, a predetermined volumetric "charge" of liquid
foamable resin is injected into the channel, such that the
channel will x>e completely filled. Finally, the liquid
foam resin foams and rises upwardly through the elongated
channel, completely filling the channel with resin foam.
In a typical application, the nozzle of a plural-
component liquid foamable resin spray gun is inserted into
the upper open end of the channel. The spray gun is
oriented and adjusted to direct a thin high-pressure high-
velocity stream of a foamable plural-component liquid
resin, such as a polyurethane, into the channel, generally
parallel to the channel inside walls. The liquid stream
pressure is adjusted to carry the liquid stream
substantially to the bottom of the channel to prevent foam
blockage, as described. The polyurethane foam then rises
through the channel, completely filling the channel and
eliminating voids. Other advantages and meritorious
features of the method of this invention will be more
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fully understood from the following detailed description
of the preferred embodiments of the method of this
invention, they drawings and the appended claims of the
invention.
BRIEF DESCRIPTION OF THE DRAV~IINGS
Figure 1 is an elevated perspective view of an
extruded lineal filled with polymeric foam by the method
of this invention;
Figure 2 is a partially cross-sectional view of an
extruded lineal supported at the most preferred angle
being filled with polymeric foam illustrating the method
of this invention;
Figure 3 is a partial side perspective view of one
end of the lineal illustrating a method of temporarily
sealing the channels of the lineal;
Figure 4 is a partial side view of a container of
extruded lineals of the type shown in Figure 1 supported
for the method of filling elongated channels with foam of
this invention; and
Figure 5 is an end view of the container of extruded
lineals shown .in Figure 4, in the direction of view arrows
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DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE METHOD OF
THIS INVENTION
As described, the method of filling elongated
channels with foam of this invention is particularly
adapted to filling relatively small cross-sectional area
elongated channels with foam, including plural-component
foams, such as polyurethane. The method of this invention
will now be described in relation to the filling of the
channels of a.n extruded lineal, such as used by the
prefabricated window industry. It will be understood,
however, that the method of this invention is not limited
to this particular application, but may be used in many
applications requiring the filling of elongated channels,
particularly channels having a relatively small cross-
sectional area and where the cross-sectional shape of the
channel is complex ar varies from channel-to-channel. In
such applications, it may be impractical to use a
prefabricated foam core.
Figure 1 illustrates a typical extruded polyvinyl
chloride lineal 20, such as used by the prefabricated
window and sliding door industry. The length L of the
extruded lineal is relatively long, compared to its width.
Extruded lineals of this general type are available in 14-
foot and greater lengths, such that PVC extruded lineal
are relatively flexible. It is preferred by the window
manufacturers that the internal channels 22 and 24 are
filled with a polyurethane foam having a density ranging
from about 0.5 pcf to 3.0 pcf or greater. The foam core
impedes air infiltration into the channels and provides a
thermal and sound attenuation barrier. Where a relatively
rigid foam is used (e.g. 3.0 pcf or greater) , the foam
core also substantially improves the structural rigidity
of the extruded lineal. Although prefabricated foam cores
have been used., this method of filling the channels with
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a foam core is generally impractical because the shape of
the channels may be relatively complex, as shown, and the
extruded lineal may have several channels to be filled
with foam. An. extruded lineal 20 having two channels 22
and 24 to be filled with foam 26 is illustrated in the
drawings of this application to describe the method of
this invention.
The disclosed extruded lineal 20 also includes open
channels 28 at. the "top" of the extruded lineal, which
receives the glass or "lites" of an insulated window. The
bottom surface 30 is configured to support the window in
the casing. The channels 22 and 24 in an extruded lineal
are open at both ends 32 and 34. After filling the
channels with :Foam, the extruded lineals are cut to length
by the window manufacturer, depending upon the size of the
window.
In the method of this invention, the extruded lineal
is oriented in an upwardly angled orientation, as shown
in Figure 2. Where the extruded lineal 20 is relatively
20 long and flexible, the lineal is preferably supported in
an upwardly angled orientation by a suitable support
fixture 36. In the disclosed embodiment, the support
fixture 36 includes generally vertical legs or braces 38
and top and be>ttom panels 40 and 42, respectively, which
support a suitable portion of the extruded lineal 20. The
support fixture may be formed of any suitable material,
including wood.
The lower end 32 of the extruded lineal is preferably
temporarily sealed during filling. In the disclosed
embodiment, the lower end 32 of the extruded lineal is
sealed with tape 44, as shown in Figure 3. The tape 44 is
simply applied over the lower end 32 of the channels 22
and 24, tempor;~rily sealing the channels during filling of
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the channels with foam. The lower ends of the channels
may also be plugged or sealed by any other suitable means .
It will be understood, however, that the "seal" may be a
relatively low-pressure seal because of the method
described, an<i the escape of a small volume of foam
through the lower end should not cause a problem.
In the method of this invention, a liquid foamable
resin is introduced into the upper end 34 of the extruded
lineal in the form of a thin, relatively high-pressure
high-velocity stream which carries the liquid stream
substantially down the length of the elongated lineal,
prior to contacting the inside walls of the channel and
creaming. In the disclosed embodiment, the liquid stream
is generated b~~r a conventional dispensing gun 46. The gun
is oriented anal adjusted to direct a thin, high-pressure
stream of a foamable plural-component liquid resin into
one of the channels 22 or 24 of the extruded lineal 20, as
shown in Figure 2. The nozzle of the dispensing gun is
introduced into the open end 34 of the extruded lineal and
triggered, directing a thin, relatively high-pressure
stream of liquid foamable resin into the channel,
generally parallel to the side walls of the channel and
preferably coincident with the longitudinal axis of the
channel. In the preferred method of this invention, a
predetermined volumetric "charge" of liquid foamable resin
is introduced into each channel to substantially
completely fill the channel with foam. The appropriate
charge may be determined by trial and error, or the volume
may be calculated for each channel configuration.
As will be understood by those skilled in the art,
even a relatively thin, high-pressure stream of liquid
foamable resin generated by a conventional dispensing gun
will expand with distance. In a 14-foot length, for
example, a relatively thin-diameter stream (e. g. 0.070
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in.) will exp<~nd to a diameter greater than the cross-
sectional area of a small cross-sectional channel. It is
a feature of the method of this invention, however, that
the diameter of the stream and line pressure are adjusted
to carry the stream downwardly through the channel a
substantial distance prior to contacting the inside walls
of the channel and "creaming," thereby avoiding blocking
of the flow of liquid foamable resin through the channel.
In the preferred method of this invention, the liquid
stream reaches the bottom of the channel prior to closure
of the channel with foam, although the liquid stream may
contact the inside walls of the channel above the bottom
32 of the channel.
It has been found that the most preferred angle of
the channel to be filled, relative to horizontal, for the
method of thi:~ invention is generally about 60 degrees,
with a variance of about 10 degrees. This angle assures
complete filling and limits voids in the foam core in most
applications of the type described. As will be
understood, the combined viscosity of the liquid foamable
resin, temperature, pressure and diameter of the stream
must be selected to assure that the liquid foamable resin
reaches the bottom or near the bottom of the channel to
form a void-free foam core which completely fills the
channel. A slew reacting foamable resin is preferred for
most applicati~~ns, particularly where the cross-sectional
area of the channel is small compared to the length.
Smaller angles to about 30 degrees may be used,
particularly where the cross-sectional area of the channel
is greater and larger angles, preferably less than 90
degrees, may also be used depending upon the application
and operating conditions. It has been found that an angle
of 90 degrees relative to horizontal with a channel having
a small cross-sectional area results in voids which are
not found at 70 degrees, for example. The foam
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composition will generally be dictated by the application
and customer requirements. The preferred angle of
generally about 60 degrees relative to horizontal was,
however, found to be particularly suitable for a
relatively slow reacting polyurethane foam at the
operating conditions described herein.
The liquid foamable resin then "blows" and rises
upwardly through the elongated channel, filling the
channel with resin foam. The opening through the upper
end 34 of thE~ channel may be gated to optimize back
pressure of fc>am blow, and the foam is allowed to rise,
filling the channel to the upper opening or entry port.
The entry port remains partially open to allow the venting
of pressure as the foam rises up the channel. The
channels of the lineals are filled individually or in
groups, as shown in Figures 4 and 5. Extruded lineals are
typically received packed in a container, such as the
cardboard box 52 Shawn in Figures 4 and 5. The extruded
lineals 20 are: tightly packed in the box 52 in parallel
relation to save shipping costs. The method of this
invention may be utilized to fill the channels of the
extruded lineals without removing the lineals from the
shipping container 52, as now described. The shipping
container is i~irst supported at the desired angle on a
support fixture 54 having a leg 56 and a support 58, which
is angled relat=ive to the support 56 at the desired angle.
The nozzle of the application gun 46 is then introduced
into the open end of a channel of one of the lineals and
triggered to direct a thin, relatively high-pressure
stream of liquid foamable resin into the elongated
channel, parallel to the side walls of the channel, as
described.
In the preferred method, a predetermined volumetric
charge of liquid foamable resin is introduced into each of
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the channels, depending upon the volume, such that the
operator can fill the next channel prior to completion of
the rise of the foam through the last channel, thereby
reducing the i:ime required to fill the channels. In a
typical application, wherein the method of this invention
is utilized to fill the channels of extruded lineals of
the type discl~~sed, the charge of liquid foamable resin is
completed in <~bout two seconds or less. The foam then
blows and rises through the channel, filling the channel,
in about five seconds or less. Thus, the method of this
invention is very efficient, requiring only one operator.
Further, in the method disclosed in Figures 4 and 5, it is
not necessary to temporarily seal the lower ends of the
channels of th.e extruded lineals because the pressure of
the lineals against the lower end 60 of the shipping
container 52 is sufficient to prevent substantial escape
of the foam.
As will be understood, the diameter of the high-
pressure stream will be dependent upon the cross-sectional
area and length of the channels to be filled. In a
typical application, wherein the method of this invention
is utilized tc> fill the channels of extruded lineals of
the type disclosed, the cross-sectional areas of the
channels will range from about 0.5 square inches or
smaller to 2 square inches or greater. A high-pressure
high-velocity stream having a diameter of about 0.070
inches has been found suitable for most applications of
this type. Further, the preferred pressure of the stream
will also be dependent upon the length of the channels to
be filled. A hydraulic line pressure for a conventional
application gun of 400 to 500 psi has been found suitable
for this application. As described above, a polyurethane
foam having a density of about 0.5 pcf to 3.0 pcf is
preferred by the prefabricated window industry. The
processing temperature is typically in the range of 70 to
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100° F, preferably about 85° F, and may be fixed by the
temperature control equipment in a conventional
application gun. Further, the predetermined "charge" of
liquid foamab:Le resin may be fixed by the volumetric
dispensing equipment on the machine. The preferred
volumetric charge is dependent upon the internal volume of
the channel anc3 the specified in situ density of the foam.
Suitable application guns useful for the method of
this invention are available from Gusmer Corporation,
including the Model D-Gun or the GX 7 Gun. The gun is
adjusted to form a thin, relatively high-pressure, high-
velocity stream of liquid foamable resin. Of course, the
combined density of the liquid foamable resin will also
affect the generation of the stream and the preferred
resin foam wil:L depend upon the particular application for
the foam-filled channel. As described, the density of the
foam core may range from a relatively flexible open-cell
foam having a density of about 0.5 pcf to a more rigid
closed-cell foam having a density of 3.0 pcf or greater.
The greater density foams will add structural rigidity to
the extruded lineal. The process of this invention may,
however, accommodate many applications. A thin,
relatively high-pressure, high-velocity stream may be
generated, for example, with liquid polyurethane foamable
resins having a combined density of 300 to 1000 cps at
operating temperatures of 85 to 100° F. A relatively slow
reacting foama.ble resin is, however, preferred to avoid
blocking the channel where the resin contacts the inside
walls above the lower end of the lineal. Thus, the method
of this invention is not limited to any specific foam or
foam formulation.
Further, the method of this invention is not very
sensitive to t:he skill of the applicator. For example,
the dispensing gun 46 may be hand-held, without fixtures,
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wherein the nozzle of the gun is oriented to direct the
stream of liquid foamable resin generally coincident with
the axis of i=he channel in the extruded lineal. This
method has resulted in the filling of the channels of
extruded linea.ls having lengths of 14 feet and greater.
Further, the foam cores in the extruded lineals filled by
the method oi: this invention have been found to be
substantially free of voids, contrary to the prior art
methods described above. The method of this invention
therefore provides several important advantages over the
prior art. First, as described above, the extruded
lineals may bE: filled with only operator, reducing labor
costs. Second, the method of this invention does not
require relatively movement of the dispensing gun and the
lineal, resulting in a simpler, more efficient method.
Third, the method of this invention substantially reduces
voids in the foam core, which is a primary object of the
invention. Fourth, the method of this invention takes
substantially less time to complete than the prior art
methods. Finally, the method of this invention permits
the application of a wider range of foam compositions and
is less sensitive to operator skill. As will be
understood, a :relatively simple fixture may be utilized to
fill several channels at a time because there is no
relative movement between the dispensing gun and the
lineal. The mE~thod of this invention therefore fulfills
the objects of the invention, as described above.
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