Title: Method of filling a muffler cavity with fibrous material
Abstract: A method for filling a muffler shell with a fibrous material includes providing an outer muffler shell, applying a temporary form to the outer shell to define a muffler chamber within the outer muffler shell, and wetting the fibrous material by forcing moisturized compressed air into contact with the fibrous material. The wetted fibrous material is inserted into the muffler chamber, and the temporary form is removed from the outer muffler shell.
Patent Number: 6,883,558 Issued on 04/26/2005 to Jander
| Inventors:
|
Jander; Michael H. (Eupen, BE)
|
| Assignee:
|
Owens Corning Composites, S.P.R.L. (Brussels, BE)
|
| Appl. No.:
|
675182 |
| Filed:
|
September 30, 2003 |
| Current U.S. Class: |
141/1; 141/67; 141/70; 29/890.08 |
| Intern'l Class: |
B65B 001//04 |
| Field of Search: |
141/1,67,11,12,70,71
181/222,252,256,257,258
29/890.08
|
References Cited [Referenced By]
U.S. Patent Documents
| 5036585 | Aug., 1991 | Schweinfurth.
| |
| 5976453 | Nov., 1999 | Nilsson et al.
| |
| 6068082 | May., 2000 | D'Amico, Jr. et al.
| |
| 6148519 | Nov., 2000 | Stenersen et al.
| |
| 6317959 | Nov., 2001 | Nilsson et al.
| |
| 6446750 | Sep., 2002 | Lewin.
| |
| 6457555 | Oct., 2002 | Saughnessy.
| |
| 6581723 | Jun., 2003 | Brandt et al.
| |
| 2001/0011780 | Aug., 2001 | Knutsson.
| |
| 2003/0042070 | Mar., 2003 | Brandt et al.
| |
| 2003/0047381 | Mar., 2003 | Brandt et al.
| |
Primary Examiner: Douglas; Steven O.
Attorney, Agent or Firm: Eckert; Inger H., Gasaway; Maria C.
Claims
1. A method for filling a muffler shell with a fibrous material comprising the
steps of:
(a) providing an outer muffler shell;
(b) applying a temporary form to the outer shell to define a muffler chamber
within the outer muffler shell;
(c) wetting the fibrous material by forcing moisturized compressed air into contact
with the fibrous material;
(d) inserting the wetted fibrous material into the muffler chamber; and
(e) removing the temporary form from the outer muffler shell.
2. The method of claim 1 wherein the outer muffler shell of step (a) is comprised
on an upper outer shell and a lower outer shell, and wherein the temporary form
of step (b) is applied to the lower outer shell.
3. The method of claim 1 wherein the fibrous material in step (c) is simultaneously
textured and wetted by forcing moisturized compressed air into contact with the
fibrous material.
4. The method of claim 1 wherein the inserting step (d) is accomplished by drawing
a partial vacuum in the enclosed muffler chamber while inserting the fibrous material
to draw the fibrous material into the enclosed muffler chamber.
5. The method of claim 1 wherein the compressed air is moisturized by using water.
6. The method of claim 1 wherein the compressed air has sufficient moisture to
wet the fibrous material to a moisture content that is within the range of from
about five to about fifty percent of the weight of the combined fibrous material
and moisture.
7. The method of claim 1 wherein the fibrous material inserted into the outer
shell is covered with a layer of protective material following step (e) such that
the material encases the fibrous material extending over the outer shell.
8. The method of claim 7 wherein the protective material used to cover the fibrous
material is a fibrous glass material.
9. The method of claim 7 wherein the protective material used to cover the fibrous
material is paper.
10. A method for filling a muffler shell with a fibrous material comprising the
steps of:
(a) providing an outer muffler shell having at least one muffler chamber defined
within the outer muffler shell;
(b) wetting the fibrous material by forcing moisturized compressed air into contact
with the fibrous material; and
(c) inserting the wetted fibrous material into the muffler chamber.
11. The method of claim 10 wherein the fibrous material in step (b) is simultaneously
texturized and wetted by forcing moisturized compressed air into contact with the
fibrous material.
12. The method of claim 10 wherein the compressed air is moisturized by using water.
13. The method of claim 10 wherein the compressed air has sufficient moisture
to wet the fibrous material to a moisture content that is within the range of from
about five to about fifty percent of the weight of the combined fibrous material
and moisture.
14. The method of claim 10 wherein the fibrous material inserted into the outer
muffler shell is covered with a layer of protective material following step (c)
such that the material encases the fibrous material extending over the outer muffler shell.
15. The method of claim 14 wherein the protective material used to cover the
fibrous material is a fibrous glass material.
16. The method of claim 14 wherein the protective material used to cover the
fibrous material is paper.
17. A method for filling a muffler shell with a fibrous material comprising the
steps of:
(a) providing a muffler shell having a lower outer shell;
(b) applying a temporary form to the lower outer shell to define a muffler chamber
within the lower outer shell;
(c) texturizing the fibrous material by forcing compressed air through the fibrous
material;
(d) wetting the texturized fibrous material by applying water to the texturized
fibrous material;
(e) inserting the texturized and wetted fibrous material into the enclosed muffler
chamber; and
(f) removing the temporary form from the lower outer shell.
18. The method of claim 17 wherein the inserting step (e) is accomplished by
drawing a partial vacuum in the enclosed muffler chamber while inserting the fibrous
material to draw the fibrous material into the enclosed muffler chamber.
19. The method of claim 17 wherein the fluid is applied to the texturized material
such that the fibrous material is wetted to a moisture content that is within the
range of from about five to about fifty percent of the weight of the combined fibrous
material and fluid.
20. The method of claim 17 wherein the fibrous material inserted into the lower
outer shell is covered with a layer of protective material following step (f) such
that the material encases the fibrous material extending over the lower outer shell.
21. The method of claim 20 wherein the protective material used to cover the
fibrous material is a fibrous glass material.
22. The method of claim 20 wherein the protective material used to cover the
fibrous material is paper.
23. A method for filling a muffler shell with a fibrous material comprising the
steps of:
(a) providing a muffler shell having a lower outer shell;
(b) applying a temporary form to the lower outer shell to define a muffler chamber
within the lower outer shell;
(c) simultaneously texturizing and wetting the fibrous material by forcing moisturized
compressed air into contact with the fibrous material;
(d) inserting the wetted fibrous material into the muffler chamber; and
(e) removing the temporary form from the lower outer shell.
24. The method of claim 23 wherein the inserting step (d) is accomplished by
drawing a partial vacuum in the enclosed muffler chamber while inserting the fibrous
material to draw the fibrous material into the enclosed muffler chamber.
25. The method of claim 23 wherein the compressed air is moisturized by using water.
26. The method of claim 23 wherein the compressed air has sufficient moisture
to wet the fibrous material to a moisture content that is within the range of from
about five to about fifty percent of the weight of the combined fibrous material
and moisture.
27. The method of claim 23 wherein the fibrous material inserted into the lower
outer shell is covered with a layer of protective material following step (e) such
that the fibrous material extending over the lower outer shell is encased by the material.
28. The method of claim 27 wherein the protective material used to cover the
fibrous material is a fibrous glass material.
29. The method of claim 27 wherein the protective material used to cover the
fibrous material is paper.
Description
TECHNICAL FIELD
This invention relates to a method of filling a muffler shell with fibrous material.
More particularly, the invention pertains to a method of filling a muffler shell
that prevents the fibrous material from expanding beyond the cavity in the muffler
to be filled.
BACKGROUND OF THE INVENTION
Exhaust mufflers often include a sound absorbing material within the interior
of the muffler to dampen the sound made by the escaping gases that pass through
the muffler. Many types of exhaust mufflers are produced by mechanically joining
multiple pieces to form a muffler shell. For example, a common type of exhaust
muffler is a clamshell muffler, which is assembled by joining an upper section
to a lower section by welding or crimping. Another common construction for mufflers
uses a single body portion that is sealed by joining end portions to the body portion
by welding or crimping. A common material used to fill exhaust mufflers is glass
fibers. The fibers usually fill at least part of the interior muffler cavity, and
are often inserted into the muffler in a volumized form that makes them somewhat
difficult to contain. Often, when volumized fibers are used, fibers stray from
the interior muffler cavity and become trapped between the sections of the muffler
shell. The trapped fibers subsequently have an adverse effect on the quality of
the joint between the sections of the muffler. Hence, there is a need for an improved
muffler filling process.
SUMMARY OF THE INVENTION
The above objects as well as other objects not specifically enumerated are achieved
by a method for filling a muffler shell with a fibrous material. The method includes
providing an outer muffler shell, applying a temporary form to the outer shell
to define a muffler chamber within the outer muffler shell, and wetting the fibrous
material by forcing moisturized compressed air into contact with the fibrous material.
The wetted fibrous material is inserted into the muffler chamber, and the temporary
form is removed from the outer muffler shell.
According to this invention there is also provided a method for filling
a muffler shell with a fibrous material. The method includes providing an outer
muffler shell having at least one muffler chamber defined within the outer muffler
shell, wetting the fibrous material by forcing moisturized compressed air into
contact with the fibrous material, and inserting the wetted fibrous material into
the muffler chamber.
According to this invention there is also provided a method for filling
a muffler shell with a fibrous material. The method includes providing a muffler
shell having a lower outer shell, applying a temporary form to the lower outer
shell to define a muffler chamber within the lower outer shell, texturizing the
fibrous material by forcing compressed air through the fibrous material, and wetting
the texturized fibrous material by applying water to the texturized fibrous material.
The texturized and wetted fibrous material is inserted into the enclosed muffler
chamber, and the temporary form is removed from the lower outer shell.
According to this invention there is also provided a method for filling
a muffler shell with a fibrous material, where the method includes providing a
muffler shell having a lower outer shell, and applying a temporary form to the
lower outer shell to define a muffler chamber within the lower outer shell. The
fibrous material is simultaneously texturized and wetted by forcing moisturized
compressed air into contact with the fibrous material. The wetted fibrous material
is inserted into the muffler chamber, and the temporary form is removed from the
lower outer shell.
Various objects and advantages of this invention will become apparent to
those skilled in the art from the following detailed description of the preferred
embodiments, when read in light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view in perspective of the lower outer shell of a muffler.
FIG. 2 is a schematic view in perspective of the temporary form fitted onto
the lower outer shell.
FIG. 3 is a schematic view in perspective of the temporary form fitted onto
a lower outer shell having a permanent partition mounted therein.
FIG. 4 is a side elevational view of the temporary form fitted onto the lower
outer shell.
FIG. 5 is schematic view in perspective of a perforated temporary form fitted
onto the lower outer shell.
FIG. 6 is a schematic view in perspective of a cylindrical muffler shell having
a plurality of permanent partitions mounted therein.
FIG. 7 is a schematic view in perspective of the enclosed muffler chamber being
filled with fibrous material according to the method of the invention.
FIG. 8 is a cross-sectional view in elevation of a first embodiment of the filling
apparatus that simultaneously texturizes and wets the fibrous material prior to
inserting the fibrous material into the enclosed muffler chamber.
FIG. 9 is a cross-sectional view in elevation of a second embodiment of the
filling apparatus that texturizes and then wets the fibrous material using moisturized
compressed air to insert the fibrous material into the enclosed muffler chamber.
FIG. 10 is a cross sectional view in elevation of the filling apparatus used
to first texturize and then wet the fibrous material prior to inserting the fibrous
material into the enclosed muffler chamber.
FIG. 11 is a schematic view in perspective of the fibrous material inserted
into the lower outer shell.
FIG. 12 is a schematic view in perspective of the fibrous material encased in
a protective material after the fibrous material has been inserted into the lower
outer shell.
FIG. 13 is a schematic view in perspective of a completed muffler assembly.
DETAILED DESCRIPTION OF THE INVENTION
Exhaust muffler shells are generally formed in multiple pieces, which are
subsequently joined together by any suitable mechanical fastening operation, such
as welding or crimping. FIGS. 1 and 13 illustrate a common configuration for a
muffler shell design often referred to as a clamshell muffler. A clamshell muffler
11 is generally comprised of a lower outer shell
10 and an upper
outer shell
40. Generally, the lower outer shell
10 and upper outer
shell
40 are formed from a metal or metal alloy material, although it will
be appreciated that any suitable material may be used for the lower outer shell
10 and upper outer shell
40. The lower outer shell
10 and
upper outer shell
40 can be formed using any suitable forming process, such
as hydroforming or stamping, and can be formed having any suitable shape and dimensions.
In a preferred embodiment, the lower outer shell
10 and the upper outer
shell
40 are generally formed such that the completed muffler assembly has
an elongated elliptical shape, with each portion of the shell shaped as one half
of the ellipse divided symmetrically about the horizontal axis of the completed
muffler assembly. As shown in FIG. 1, the lower outer shell
10 has an internal
cavity
13.
As shown in FIGS. 2 through 4, prior to filling the muffler with fibrous material,
a temporary form
12 may be placed over the lower outer shell
10 to
define a muffler chamber
14. The temporary form
12 preferably has
a concave shape similar to the shape of the upper outer shell
40, although
it will be appreciated that the temporary form
12 may have any suitable
shape. The temporary form
12 may also include a back plate
16 that
can be positioned within the internal cavity
13 of the lower outer shell
10 to define the muffler chamber
14. The temporary form
12
may be formed from any suitable rigid material, such as metal or plastic. Alternatively,
the upper outer shell
40 may be used in place of the temporary form
12
to define the muffler chamber
14.
As shown in FIG. 3, the lower outer shell
10 may also contain an internal
structure
17, consisting of any number and combination of pipes, partition
plates, or baffles. The internal structure
17 is adapted to extend at least
part way through the internal cavity
13 of the lower outer shell
10
to define the muffler chamber
14 within the internal cavity
13. Where
the internal structure
17 defines the muffler chamber
14, the shape
of the temporary form
12 may be adapted such that the temporary form
12
works in conjunction with the internal structure
17 to define the muffler
chamber
14. Once again, the upper outer shell
40 may be used in place
of the temporary form
12 to define the muffler chamber
14.
Referring to FIGS. 2 and 3, a plurality of sealable outlets
15 may
also be included on the temporary form
12. The sealable outlets
15
may be used for additional operations in the filling process, such as the drawing
of a vacuum within the muffler chamber
14 using vacuum lines, not shown,
connected to the temporary form
12 through the outlets
15. The outlets
15 may be any size and shape suitable for connecting the vacuum lines to
the temporary form
12, and consist generally of one or more holes in the
temporary form
12. The outlets
15 in the temporary form
12
may be covered or capped to seal the outlets
15 when they are not being
used. The temporary form
12 may also include a fill opening
18 to
accommodate the filling apparatus used to insert the fibrous material into the
muffler chamber
14. The fill opening
18 may be placed in any suitable
location on the temporary form
12. In a preferred embodiment, the fill opening
18 is placed along the joint between the lower outer shell
10 and
the temporary form
12.
FIG. 5 shows an alternative embodiment of the invention using a perforated form
20. The perforated form
20 is similar in size and shape to the temporary
form
12, but is formed from a material having perforations
22. The
perforations
22 may be of any suitable size and shape to allow air entering
the muffler chamber
14 during the filling process to escape the muffler
chamber
14, subsequently allows the fibrous material to fully fill the muffler
chamber
14. The perforated form
20 may also include an opening
24
placed along the joint between the lower outer shell
10 and the perforated
form
20 to accommodate the filling apparatus. It will be appreciated however,
that the opening
24 may also be omitted, as any of the perforations
22
on the perforated form
20 may be used to accommodate the introduction of
the fibrous material.
FIG. 6 illustrates an alternate muffler construction that may be filled according
to the method of the present invention. In this embodiment, the outer shell
50
is comprised of a single body portion, as opposed to a clamshell muffler having
an upper outer shell and a lower outer shell section. The outer shell
50
may be formed from a metal or metal alloy material, although it will be appreciated
that any suitable material may be used to form the outer shell
50. The outer
shell
50 can be formed using any suitable forming process, and can be formed
having any suitable shape and dimensions. In a preferred embodiment, the outer
shell
50 is generally formed having an elongated cylindrical shape that
is open on each end
51,
52. The outer shell
50 may also contain
at least one internal partition
54 to define individual muffler chambers
14 within the outer shell
50, although it will be appreciated that
the internal partition
54 is not required. Where the single outer shell
construction is used, the temporary form
12 may be omitted from the filling
process, as the muffler chamber
14 defined by the outer shell
50
and the internal partition
54 is sufficiently enclosed to be filled according
to the method of the present invention. To complete this type of muffler assembly,
an end cap
53 is fastened to the each open end
51,
52 of the
outer shell
50 using any suitable mechanical fastening means, such as welding,
crimping, or fastening mechanisms.
After the lower outer shell
10 is fitted with the temporary form
12
or upper outer shell
40, the muffler chamber
14 is ready to be filled
with fibrous material. A filling apparatus
26 is inserted into the fill
opening
18 of the temporary form
12 to fill the muffler chamber
14.
The filling apparatus
26 will be explained in greater detail below. At this
point, a vacuum apparatus, not shown, may also be connected to the sealable inlets
15 on the temporary form
12. The vacuum apparatus may be used to
draw a partial vacuum in the enclosed muffler chamber
14 during the filling
process to draw the fibrous material
29 into the enclosed muffler chamber
14. Where a single outer shell
50 design is used, as shown in FIG.
6, the filling apparatus
26 may be inserted directly into an open end
51,
52 of te outer shell
50.
FIGS. 8-10 illustrate various embodiments of the filling apparatus
26
used to fill the muffler chamber
14 with fibrous material in accordance
to the method of the present invention. The filling apparatus
26 is comprised
of a fibrous material inlet
30, at least one compressed air inlet
34,
a fluid inlet
36, a texturizing chamber
31, and a filling nozzle
28. In a first embodiment, shown in FIG. 8, the fluid inlet
36 may
be connected to the compressed air inlet
34. In a second embodiment, shown
in FIG. 9, the fluid inlet
36 is independent of the compressed air inlet
34. In a third embodiment, shown in FIG. 10, the fluid inlet
36 is
attached to the filling nozzle
28.
FIG. 8 illustrates the filling apparatus
26 having a fluid inlet
36
connected to the compressed air inlet
34. To fill the muffler chamber
14,
a rope
29 of fibrous material is inserted into the fibrous material inlet
30. The rope
29 of fibrous material is preferably a multi-stranded
rope of straight glass fibers, although it will be appreciated that any suitable
fibrous material may be used. As the rope
29 is fed through the filling
apparatus
26, the rope
29 enters a texturizing chamber
31.
The compressed air inlet
34 provides compressed air to the texturizing chamber
31. The fluid inlet
36, which is connected to the compressed air
inlet
34, provides a metered flow of fluid into the compressed air prior
to the compressed air's entering the texturizing chamber
31. The addition
of the fluid moisturizes the compressed air. Preferably, the fluid used to moisturize
the compressed air is water, although it will be appreciated many suitable wetting
fluid may be used to moisturize the compressed air. When the rope
29 enters
the texturing chamber
31, the moisturized compressed air within the texturizing
chamber
31 separates and tumbles the individual glass fibers
33 of
the rope
29. The moisture in the compressed air also wets the individual
glass fibers
33 during this texturizing process. After the fibers
33
have been texturized and wetted, the fibers
33 are advanced into the filling
nozzle
28. The fibers
33 are propelled by the compressed air in the
texturing chamber
31 through the filling nozzle
28 and out an open
end
35 in the filling nozzle
28. The open end
35 of the filling
nozzle
28 is inserted into the fill opening
18 of the temporary form
12.
The texturizing of the individual glass fibers
33 fluffs the individual
glass fibers
33 by bending and twisting the fibers
33, which allows
the fibers
33 to fill the muffler chamber
14 when the fibers
33
are inserted. The wetting of the fibers
33 supplies a cohesive force that
keeps the texturized fibers
33 from expanding beyond the bounds of the shape
set by the temporary form
12 when the temporary form
12 is removed.
Where a single outer shell
50 configuration is used, the cohesive force
of the wetted fibers prevents the texturized fibers
33 from expanding beyond
the bounds of the outer shell
50. The holding together of the wetted fibers
provide provides a particular advantage over unwetted fibers because the wetted
fibers will subsequently not expand or spring out of the temporary form
12
when the temporary form
12 is removed from the lower outer shell
10.
Where a single outer shell construction is used, the wetted fibers will not expand
or spring out of the muffler chamber
14 defined by the outer shell
50.
Thus, the cohesive force supplied by the wetting process prevents substantially
any of the fibers from straying onto the joining surface for either the lower outer
shell
10 and the upper outer shell
40 or the outer shell
50
and the end caps
53.
FIG. 9 shows a second embodiment of the filling apparatus
26B, which
contains a fluid inlet
36 that is independent of the compressed air inlet
34. The fluid inlet
36 provides a fluid source directly into the
texturizing chamber
31, as opposed to connecting the fluid inlet
36
to the compressed air inlet
34 to moisturize the compressed air, as in the
previous embodiment. The compressed air inlet
34 supplies compressed air,
which is not moisturized, into the texturizing chamber
31. When the rope
29 enters the texturizing chamber
31, the compressed air within the
texturizing chamber
31 separates and tumbles the individual glass fibers
33 of the rope
29. At the same time that texturization of the fibers
33 occurs, a metered flow of fluid is dispensed into the texturizing chamber
31. The fluid provided directly into the texturizing chamber
31 wets
the fibers
33 during the texturization process before they are moved by
the compressed air into the filling nozzle
28. Preferably, the fluid used
to wet the fibers
33 is water, although it will be appreciated that any
suitable wetting fluid may be used to wet the fibers
33. After the fibers
33 have been texturized and wetted, the fibers
33 are advanced into
the filling nozzle
28. The fibers
33 are propelled by the compressed
air in the texturing chamber
31 through the filling nozzle
28 and
out an open end
35 in the filling nozzle
28. The open end
35
of the filling nozzle
28 is inserted into the fill opening
18 of
the temporary form
12.
FIG. 10 shows a third embodiment of the filling apparatus
26C, which
also contains a fluid inlet
36 that is independent of the compressed air
inlet
34. However, in this embodiment, the fluid inlet
36 provides
fluid into the filling nozzle
28 instead of into the texturizing chamber
31. As with the second embodiment, the compressed air inlet
34 supplies
compressed air, which is not moisturized, into the texturizing chamber
31.
When the rope
29 enters the texturizing chamber
31, the compressed
air within the texturizing chamber
31 separates and tumbles the individual
glass fibers
33 of the rope
29. After the fibers
33 have been
texturized, the fibers
33 are advanced into the filling nozzle
28.
A fluid inlet
36 positioned on the filling nozzle
28 supplies a metered
fluid flow into the filling nozzle
28. Preferably, the fluid used to wet
the fibers
33 is water, although it will be appreciated that any suitable
wetting fluid may be used to wet the fibers
33. As the fibers
33
enter the filling nozzle
28 they are wetted by the fluid provided in the
filling nozzle
28. The texturized and wetted fibers
33 are then expelled
out the open end
35 in the filling nozzle
28. The open end
35
of the filling nozzle
28 is inserted into the fill opening
18 of
the temporary form
12.
Regardless of which filling apparatus configuration is used, the fibers
33 entering the muffler chamber
14 from the filling nozzle
28
are always wetted. To achieve an adequate cohesive force to hold the wetted fibers
33 together, it is preferable to either have sufficient moisture content
in the compressed air where moisturized air is used for wetting, or to have sufficient
fluid flow over the fibers
33 where a separate wetting process is used.
In a preferred embodiment, the amount of moisture content provided to the fibers
33 is within the range of from about five to about fifty percent of the
weight of the combined fibers
33 and moisture. It will be appreciated, however,
that any suitable amount of moisture content sufficient to hold the fibers
33
together may also be used.
Returning to FIG. 7, after the filling nozzle
28 has been inserted
into the fill opening
18 of the temporary form
12, the wetted fibers
33 are inserted into the muffler chamber
14. As previously discussed,
a partial vacuum may be drawn within the muffler chamber by attaching vacuum hoses
to the sealable outlets
15 on the temporary form
12 to draw the wetted
fibers
33 into the muffler chamber
14, although drawing of the partial
vacuum is not required. The muffler chamber
14 is filled with any suitable
amount of wetted fibers
33 to obtain any desired amount of sound muffling
capability. After the muffler chamber
14 is filled with the desired amount
of wetted fibers
33, the filling apparatus
26 is removed from the
fill opening
18 and the temporary form
12 is removed from the lower
outer shell
10. FIG. 11 illustrates the wetted fibers
33 in the lower
outer shell
10 following the removal of the temporary form
12. The
wetted fibers
33 maintain the shape of the temporary form
12 due
to the moisture on the wetted fibers
33 that serves to hold the fibers
33
together and substantially prevents the wetted fibers
33 from expanding
beyond the shape of the temporary form
12 once the temporary form
12
is removed. As shown in FIG. 12, a layer of protective material
38 may also
be used to encase the wetted fibers
33 to further insure that the shape
of the wetted fibers
33 is maintained as the fluid applied to the wetted
fibers
33 evaporates. It will be appreciated, however, that the protective
material
38 is not required to maintain the shape of the fibers
33,
as the moisture applied to the fibers
33 has sufficient cohesive force to
maintain the fibers
33 in the shape set by the temporary form
12.
The layer of protective material
38 may be any suitable material for use
in exhaust mufflers. Examples of such suitable protective materials include a protective
sheet
38 made from paper or a protective sheet
38 made from glass fibers.
Following the removal of the temporary form
12 and the optional
application of a protective material
38 over the wetted fibers
33,
the lower outer shell
10 filled with the wetted fibers
33 is ready
to be combined with its companion upper shell
40. As shown in FIG. 12, the
upper shell
40 is placed over the wetted fibers
33 and fitted onto
the lower outer shell
10. Because the wetted fibers
33 are held together
by the moisture applied during the filling process, the joint between the upper
outer shell
40 and the lower outer shell
10 remains substantially
free from any stray fibers
33 that would otherwise have interfered with
the joining process. The upper outer shell
40 and the lower outer shell
10 are joined together using any suitable mechanical fastening means to
create a finished muffler assembly. In a preferred embodiment, a weld joint
44
joins the upper outer shell
40 and lower outer shell
10.
The principle and mode of operation of this invention have been described in
its preferred embodiments. However, it should be noted that this invention can
be practiced otherwise than as specifically illustrated and described without departing
from its scope.
*
