US20090320727A1

US20090320727A1 - Dust shield for refractory hanger

Info

Publication number: US20090320727A1
Application number: US12/215,905
Authority: US
Inventors: William R. Materna
Original assignee: Merkle International Inc
Current assignee: Merkle International Inc
Priority date: 2008-06-30
Filing date: 2008-06-30
Publication date: 2009-12-31

Abstract

A shield for a refractory structure that houses refractory bricks. The refractory bricks are assembled with respect to each other to form a refractory wall, roof or another refractory structure. A hanger can be used to suspend or mount at least one refractory brick. In order to extend the service life of the hanger, a shield can cover at least a portion of the hanger, such as a hanger rod, to prevent dust particles from accumulating on the rod or another hanger element. Reducing or eliminating dust particles, particularly metal dust particles, can extend the service life of hanger components and can also reduce costs associated with maintenance and repair of refractory structures, particularly within industrial furnaces.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
This invention relates to a dust shield for protecting and enhancing the life of hanger structures, particularly hangers used to suspend refractory materials in a high-temperature furnace.
1. Discussion of Related Art
Many industrial furnaces have a suspended roof construction for supporting refractory bricks that form a wall structure having a hot side exposed to relatively high temperatures within an industrial furnace. The opposite side or cold side of the suspended roof construction typically has structural members for supporting the roof construction or the wall.
Hanger rods are typically secured or connected to one or more refractory bricks. An opposite end portion of the hanger rod can be connected or secured to a structural member, for supporting or suspending the refractory bricks. Conventional hanger rods have many different sizes, shapes and configurations.
In industrial facilities that manufacture metals, such as copper or lead, the process produces undesirable metal dust or other forms of dust. During production and operation of the furnace, the metal dust accumulates on the suspended roof construction. The metal dust also collects on the hanger rods. Maintenance is often necessary to remove the accumulated dust particles from the hanger rods, to clean the metal rods.
When the metal dust accumulates on the hanger rod or other hanger structure, a coating of the metal dust can act as an insulator for the hanger rod, which prevents the rod from releasing heat for cooling purposes. Also, some metal dusts or other forms of dusts have a corrosive effect on the hanger rods. The overheating and/or the corrosive activity can cause the hanger rod to fail, often before the full service life of the refractory brick which the hanger rod supports.
Upon failure, maintenance procedures are required to remove the damaged hanger rod and replace it with a new hanger rod and refractory brick. Damaged hanger rods are costly to repair and can be dangerous, particularly if the wall or roof structure fails and damages the industrial furnace.
There is an apparent need to reduce or eliminate the overheating and/or the corrosive degrading of hanger rods, particularly those used to suspend refractory bricks in an industrial furnace. Reducing or eliminating the need to replace hanger rods can save significant maintenance costs and can also enhance the safety associated with operating the industrial furnace by reducing or eliminating hanger rod failures.

SUMMARY OF THE INVENTION

Dust shields, according to different embodiments of this invention, can be used to cover at least a portion of a hanger structure, such as a hanger rod. The dust shield can be made of any suitable material that resists heat and provides a relatively long service life. The dust shield according to this invention can have any suitable outer surface that prevents dust, particularly metal dust, from accumulating on the outside surface of the metal hangers.
Different suitable materials for the shield, particularly the outside surface, can have a relatively low coefficient of friction so that the dust particles slide off of or move away from the outside surface of the dust shield.
The dust shield can also be angled or otherwise shaped or configured to prevent or reduce dust accumulation on the outside surface of the shield. A dust shield according to this invention can have many different sizes and/or shapes, depending upon the particular design or layout of the hanger and other structural members.
In some embodiments of this invention, the dust shield covers at least a portion of the hanger rod. In other embodiments of this invention, the dust shield can cover all or any significant portion of the hanger rod or other hanger structure.
Maintenance costs can be significantly reduced by protecting or covering the hanger to reduce or eliminate dust buildup on at least a portion of the hanger. In some suspended roof constructions according to this invention, maintenance and safety aspects can be enhanced by maximizing the quantity or size of the hanger structure that is covered by the dust shield.
Dust shield according to this invention can be manufactured from metal and/or any other suitable non-metal material or material composite. In some embodiments of this invention, the dust shield is constructed from a flat material or a sheet material and forms a hollow interior. In other embodiments of this invention, the heat shield can be constructed of one or more solid or filled segments of a metal or a non-metal material. Depending upon the particular environment of the industrial furnace, the heat shield can be made from a fiber material having relatively high heat-resistant properties and/or corrosive-resistant properties.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention is explained in view of exemplary embodiments, making reference to the drawings, wherein:

FIG. 1 is a perspective view of a conventional hanger structure for one or more refractory bricks;

FIG. 2 is a perspective view of a dust shield covering at least a portion of a conventional hanger, according to one embodiment of this invention;

FIG. 3 is a perspective view of a dust shield having a conical frustum, according to one embodiment of this invention;

FIG. 4 is a top view showing a pattern, in two dimensions, that is used to form a conical frustum shaped dust shield, such as shown in FIG. 3;

FIG. 5 is a perspective view of a dust shield having a pyramidal frustum, according to one embodiment of this invention; and

FIG. 6 is a top view showing a pattern in two dimensions, that is used to form a pyramidal frustum shaped dust shield, as shown in FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

Hangers, including hanger rods, provide a structural connection between a suspended roof construction of refractory materials and existing or required structural members. For example, Merkle, U.S. Pat. No. 4,424,756 teaches a suspended roof construction for an industrial furnace. Merkle, Jr., U.S. Pat. No. 4,073,243, teaches a hanger assembly for suspending at least one refractory brick used in a high temperature industrial furnace roof construction. The entire teachings of each of U.S. Pat. No. 4,424,756 and U.S. Pat. No. 4,073,243 are incorporated by reference into and are made a part of this specification.
FIG. 1 shows refractory structure 20 as conventionally known. Plate 22 may or may not be used to encase or house one or more refractory bricks 25. As shown in FIG. 1, plate 22 covers at least a portion of a periphery of two adjacently positioned refractory bricks 25. Any other suitable encasement or housing structure can be used to support one or more refractory bricks 25. In other embodiments of this invention, refractory bricks 25 have no encasement.
Also as shown in FIG. 1, rod 32 is used to connect or suspend refractory brick 25 from support structure 34. Support structure 34 can comprise any existing support member and/or any support member furnished with refractory structure 20 or another suitable suspended refractory wall.
According to this invention, refractory structure 20 can comprise a plurality of refractory bricks 25. Refractory brick 25 of this invention can comprise any other suitable refractory shape, refractory block, refractory structure or any other suitable structure of high-temperature resistant materials, such as those used in an industrial furnace or a commercial furnace operating at relatively high temperature ranges. The sizes, designs and/or proportional dimensions of refractory brick 25 can be varied to accommodate different uses of refractory structure 20 and/or refractory brick 25, according to this invention. Refractory brick 25 can be constructed from any suitable refractory material, such as those conventional refractory materials that can withstand relatively high temperatures. In certain embodiments of this invention, refractory brick 25 can be constructed of any suitable zircon, fireclay, silica, alumina, chromite and/or silicon carbide material.
Hanger 30 can be used to suspend at least one refractory brick 25. As shown in FIGS. 1 and 2, rod 32 of hanger 30 supports two refractory bricks 25. As shown in FIGS. 1 and 2, plate 22 at least partially encompasses two refractory bricks 25, such as to form an encasement, an enclosure or a housing that accommodates each refractory brick 25. Any other suitable housing or frame can be used to mount or suspend at least one refractory brick 25. In the embodiments shown in FIGS. 1 and 2, plate 22 comprises void 24. When in a mounted or suspended position, rod 32 of hanger 30 is mounted within or passes through void 24 formed by plate 22. U.S. Pat. 4,073,243 teaches different conventional hanger structures that can be used as hanger 30 according to this invention. Although hanger 30 can be attached directly to plate 22 or another suitable housing, as shown in FIGS. 1 and 2, rod 32 passes through void 24 and into a void formed by at least one refractory brick 25.
Many industrial environments, such as metal processing facilities, generate significant amounts of dust or dust particles, particularly metal dust particles such as copper particles and lead particles. If the dust particles accumulate on hanger 30, particularly on rod 32, because the metal dust particles act as an insulator, hanger 30 and/or rod 32 cannot adequately cool by transferring heat away from hanger 30 and/or rod 32.
As shown in FIG. 2, shield 40 can be used to cover at least a portion of rod 32, for example so that dust particles do not accumulate on the portion of rod 32 that is covered by shield 40. In certain embodiments of this invention, shield 40 can cover a significantly larger portion of rod 32 than the portion shown as covered in FIG. 2.
Rod 32 can be of any suitable size, shape, material and/or configuration. As shown in FIGS. 1 and 2, rod 32 has a bend approximately at a middle section of rod 32, and also a hook at an end which is opposite the end attached to refractory brick 25. Hanger 30 and/or rod 32 can have any other suitable shape that accommodates an existing or a newly installed support structure 34. Dimensions of shield 40 can be varied to cover more or less of hanger 30 and/or rod 32.
As shown in FIGS. 2-6, shield 40 has an external shape of or similar to a frustum. As used throughout this specification and in the claims, the term frustum is intended to relate to a cone or a pyramid shape having a tip section or portion that is truncated, including but not limited to truncated by a plane that is parallel to a base of the cone or the pyramid. For purposes of this invention and encompassed by the term frustum, the plane of truncation does not need to be parallel to the base plane, for example to prevent dust from collecting on hanger 30 and/or rod 32.
In some embodiments of this invention, the frustum formed by shield 40 is a conical frustum, such as shown in FIGS. 3 and 4, or in other embodiments is a pyramidal frustum, such as shown in FIGS. 5 and 6. FIG. 3 shows a perspective three-dimensional view of shield 40 formed as a conical frustum. FIG. 4 shows a two-dimensional layout or pattern of flat material that can be cut and bent or shaped to form the three-dimensional shield 40 as shown in FIG. 3. Likewise, FIG. 6 shows a two-dimensional layout or pattern of the pyramidal frustum shape of the three-dimensional shield 40 as shown in FIG. 5.
Shield 40 can have any suitable outer surface 41 that prevents dust particles from collecting on outer surface 41. In some embodiments of this invention, outer surface 41 can have a relatively low coefficient of friction, so that dust particles cannot adhere to outer surface 41. Outer surface 41 can be positioned at any suitable angle or angle of repose, for example with respect to a longitudinal axis passing through shield 40, such as in the vertical direction shown in FIGS. 3 and 5, that prevents dust particles from collecting on outer surface 41.
As shown in FIG. 3, a cross section of shield 40 taken in a direction generally perpendicular to the longitudinal axis generally forms a circle. In a similar perpendicular direction, shield 40 as shown in FIG. 5 has a generally square cross section. A similar cross section of shield 40 according to other embodiments of this invention can have any other suitable non-circular or polygonal shape that helps prevent dust particles from collection on outer surface 41.
Shield 40 can be manufactured, formed, constructed or manufactured from any suitable sheet material, filler material, solid material, such as any suitable metal, any suitable non-metal and/or any suitable composite structure or material.
In certain embodiments of this invention, shield 40 forms a hollow space through which rod 32 passes or is mounted. In other embodiments according to this invention, shield 40 can be at least partially or entirely constructed of a filler material or a solid material, such as a fibrous material or a porous material. Any filler or solid material can have a bore or other void that accommodates rod 32 or any other element of hanger 30 that requires protection.
As shown in FIGS. 2, 3 and 5, shield 40 comprises opening 42 through which rod 32 passes or is mounted. Preferably but not necessarily, an outer surface of rod 32 forms a relatively tight fit with respect to opening 42, for example so that no or few dust particles pass through opening 42 and onto rod 32 and/or any other element of hanger 30 which requires dust protection.
FIG. 2 shows bottom surface 44 of shield 40 contacting upper surface 23 of plate 22. In a similar fashion, such as for preventing dust particles from entering the space formed by shield 40, bottom surface 44 can form a relatively tight fit with respect to upper surface 23 of plate 22. As shown in FIG. 2, plate 22 is positioned between shield 40 and at least one refractory brick 25.
As shown in FIGS. 4 and 6, shield 40 in a two-dimensional state has free ends 43 that can be welded, connected, secured or otherwise attached with respect to each other to form the shape shown in FIGS. 3 and 5. Shield 40 can also be constructed as one integrated piece.
In other embodiments of this invention, shield 40 can extend above or beyond the length of rod 32. In such embodiments, shield 40 has a pointed tip structure and is not truncated, so that dust particles do not form on an upper surface of shield 40.
While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.

Claims

1. A refractory structure having a plurality of refractory shapes, a hanger suspending at least one of the refractory shapes, and the refractory structure comprising a shield having an external shape of a frustum, the shield having an opening, and at least a portion of the hanger positioned within the opening.

2. The refractory structure according to claim 1, wherein the frustum is a conical frustum.

3. The refractory structure according to claim 1, wherein the frustum is a pyramidal frustum.

4. The refractory structure according to claim 1, wherein the shield is formed from a metal.

5. The refractory structure according to claim 4, wherein the metal is of a sheet material.

6. The refractory structure according to claim 1, wherein the shield is formed from a fibrous material.

7. The refractory structure according to claim 6, wherein the fibrous material at least partially fills the shield.

8. The refractory structure according to claim 7, wherein the fibrous material has a bore and the hanger is positioned within the bore.

9. The refractory structure according to claim 1, wherein a plate at least partially covers at least one of the refractory shapes.

10. The refractory structure according to claim 9, wherein the plate forms at least part of a void within which at least a portion of the hanger is positioned.

11. The refractory structure according to claim 9, wherein the plate is positioned between at least one of the refractory shapes and the shield.

12. The refractory structure according to claim 11, wherein a bottom surface of the shield contacts an upper surface of the plate.

13. The refractory structure according to claim 1, wherein at least a portion of the hanger has a rod shape.

14. The refractory structure according to claim 1, wherein one end of the hanger is connectible to a support structure.

15. A refractory structure comprising: a refractory shape, a hanger suspending the refractory shape, a shield having an external shape of a frustum, the shield having an opening, and at least a portion of the hanger positioned within the opening.

16. The refractory structure according to claim 15, wherein an external surface of the shield forms an angle with respect to a longitudinal axis of the shield that prevents dust from collecting on the external surface.

17. The refractory structure according to claim 15, wherein the shield is positioned close enough to the hanger to prevent dust from collecting on the hanger.

18. In a refractory structure having at least one refractory shape and a hanger suspending the at least one refractory shape, the refractory structure comprising a shield having an opening, and at least a portion of the hanger positioned within the opening and close enough to the shield to prevent dust from collecting on a covered portion of the hanger.

19. The refractory structure according to claim 18, wherein the shield is positioned close enough to the hanger to seal the opening of the shield.

20. The refractory structure according to claim 18, wherein an end of the shield which is opposite from the opening contacts the at least one refractory shape or plate housing the at least one refractory shape.