Frustum-shaped insulation for a pollution control device
View Patent ↗A preformed insulation mat is provided for use between the inner and outer end cone housing of a pollution control device. The preformed insulation includes a frustum-shaped mat. The mat is formed of primarily heat moldable, silica based glass fibers containing Al 2 O 3 and is molded at a selected temperature and for a selected time duration to heat set the fibers, whereby the frustum-shaped mat is seamless and self-supporting, requiring no shape no shape retaining elements or chemical binders.
1. A preformed insulation mat for use between the inner and outer end cone housing of an exhaust emission control device, comprising:
(a) a molded frustum-shaped mat having a substantially centrally formed opening;
(b) the mat being binderless and comprising primarily heat moldable, silica based glass fibers containing Al 2 O 3 ; and
(c) wherein the frustum-shaped mat of glass fibers is molded at a temperature of between about 400 degrees Fahrenheit for about 60 minutes and about 1300 degrees Fahrenheit for about 6 minutes to heat set the fibers whereby the frustum-shaped mat is seamless and self-supporting, requiring no shape retaining elements.
2. The insulation mat of claim 1 wherein the mat comprises:
(a) a non-woven needle-punched web of fibers; and
(b) the mat having a continuous outer peripheral edge and the opening having a continuous peripheral edge.
3. The insulation mat of claim 1 wherein the heat moldable, silica based glass fibers contain between 80-99.9% SiO 2 and 0.1-20% Al 2 O 3 .
4. The insulation mat of claim 1 wherein the mat is frusto-conical and the base plane is circular.
5. The insulation mat of claim 1 wherein the mat is frusto-conical and the base plane is elliptical.
6. The insulation mat of claim 1 wherein the mat comprises primarily heat moldable, silica based glass fibers containing Al 2 O 3 and other fibers that can withstand temperatures of up to about 2000 degrees Fahrenheit.
7. A pollution control device, comprising:
(a) a housing having an inlet end cone assembly and an outlet end cone assembly;
(b) each cone assembly comprising an inner cone housing and an outer cone housing;
(c) a preformed insulation mat disposed between the inner and outer cone housing of each end cone assembly and comprising:
(i) a molded frustum-shaped mat having a substantially centrally formed opening;
(ii) the mat being binderless and comprising primarily heat moldable, silica based glass fibers containing Al 2 O 3 ; and
(iii) wherein the frustum-shaped mat of glass fibers is molded at a temperature of between about 400 degrees Fahrenheit for about 60 minutes and about 1300 degrees Fahrenheit for about 6 minutes to heat set the fibers whereby the frustum-shaped mat is seamless and self-supporting, requiring no shape retaining elements.
8. The pollution control device of claim 7 wherein the Al 2 O 3 -containing, heat moldable, silica based glass fibers contain between 80-99.9% SiO 2 and 0.1-20% Al 2 O 3 .
9. The pollution control device of claim 7 wherein the mat is frusto-conical and the base plane is circular.
10. The pollution control device of claim 7 wherein the mat is frusto-conical and the base plane is elliptical.
11. The pollution control device of claim 7 wherein the mat comprises primarily heat moldable, silica based glass fibers and other fibers containing Al 2 O 3 that can withstand temperatures of up to about 2000 degrees Fahrenheit.
12. A method for forming a frustum-shaped insulation mat for use between the inner and outer end cone housing of a pollution control device, comprising:
(a) forming an annular-shaped fibrous mat of primarily heat moldable, silica based glass fibers containing Al 2 O 3 , and no binders;
(b) placing the fibrous mat into a substantially frustum-shaped mold, the mold comprising inner and outer housing sections, the mat disposed between the inner and outer housing sections;
(c) subjecting the fibrous mat to a temperature of between about 400 degrees Fahrenheit for about 60 minutes and about 1300 degrees Fahrenheit for about 6 minutes to heat set the glass fibers, wherein the mat is permanently molded into a seamless, self-supporting and substantially frustum-shaped insulation, requiring no shape retaining elements.
13. The method of claim 12 wherein the mat is formed from a non-woven needle-punched web of fibers, the mat having a continuous outer peripheral edge and the opening having a continuous inner peripheral edge.
14. The method of claim 13 wherein the heat moldable, silica based glass fibers contain between 80-99.9% SiO 2 and Al 2 O 3 (0.1-20%).
15. The method of claim 14 wherein the fibers comprising the flat fibrous mat initially have a moisture content of between about 2% and about 20%.