COMBUSTION CHAMBER FOR THE INCINERATION OF WASTE PRODUCTS

Abstract

A combustion chamber for use in the incineration of waste products includes an inner refractory wall which extends vertically within an outer protective wall in a spaced relationship so as to define a plenum therebetween. The inner refractory wall is constructed using a plurality of precast, refractory blocks which are stacked and arranged to define a cylindrical interior cavity. The refractory blocks include mating features on adjacent surfaces to facilitate assembly and provide structural support. For additional support, selected blocks are fixedly connected to vertical support tubes by metal tie-back anchors. To facilitate combustion, a selection of the blocks is precast with a tuyere hole in order to deliver a uniform and balanced supply of air from the plenum into the interior cavity. The precast nature of the refractory blocks enables the inner refractory wall to be constructed with great precision, thereby optimizing incineration and minimizing material degradation.

Description

FIELD OF THE INVENTION

The present invention relates generally to waste disposal and, more particularly, to combustion chambers utilized to incinerate waste products.

BACKGROUND OF THE INVENTION

A combustion chamber, or cell, is a well-known structure that is commonly used to incinerate waste products through the application of intense heat, which is typically in excess of 1000° C. For instance, wood production facilities often utilize a combustion cell to dispose of wood waste, such as sawdust and bark, created from the manufacture of wood-based products.

The heat generated by combustion chambers can, in turn, be utilized in a wide range of additional applications. For instance, in wood-based product manufacturing, the heat produced by combustion chambers is often used in the drying of finished, wood-based products. Heat produced from combustion chambers is also commonly applied to water to produce steam, which is subsequently used for, inter alia, district heating, hot water generation, and the generation of electricity by turbine generator.

Conventionally, a combustion cell is constructed as an enlarged, tower-like, chamber which includes an inner cylindrical wall that extends vertically within an outer wall, the inner wall being spaced in from the outer wall so as to define a plenum therebetween. The inner wall defines an enlarged, cylindrical interior cavity, or combustion zone, with an opening, or gas outlet, at its top end through which heat from the combustion zone escapes. A combustion grate is typically mounted at the bottom of inner wall and serves to support the waste products intended for incineration. An externally-accessible chute penetrates through both outer and inner walls at a downward angle and into communication with the combustion zone, thereby allowing for the delivery of waste product into the interior cavity.

As previously noted, a plenum is established between the outer and inner walls and allows for the delivery of air into the combustion zone to facilitate the incineration process. The primary supply of air for combustion is delivered into the interior cavity through the combustion grate. As a secondary source of air into the combustion zone, a series of small nozzles, or tuyere holes, generally circular in transverse cross-section, extend radially through the inner wall and thereby establish a fluid communication path between the plenum and the interior cavity. As can be appreciated, the number, arrangement, geometric configuration, openness, and angle of orientation of the nozzles all contribute to the effectiveness in maintaining efficient combustion of wood waste within the interior cavity.

Due to the intense heat generated within the combustion zone, it is required that the inner wall be constructed of a suitable heat-resistant material. Traditionally, the inner wall is constructed using a cylindrical, expanded metal (i.e. perforated) backbone, or support, which is welded in place. A unitary refractory liner is then applied onto the interior of the expanded metal support.

The refractory liner is typically constructed of a heat-resistant material that is initially deformable but eventually hardens through a curing process. For instance, refractory liner may be constructed of either a heat-resistant moldable refractory that is compacted with pneumatic tools onto the inner surface of the expanded metal support or a concrete-based mixture that is cast-in-place or shotcrete against the inner surface of the expanded metal support.

Prior to or during installation, tubular sleeves, often constructed using polyvinyl chloride (PVC) piping or wooden dowels, are placed within the boundaries of the lining to act as form blanks to create the nozzle openings. Additionally, the deformable nature of the pre-cured refractory liner allows for its penetration through the perforations in the expanded metal support and thereby form a means of interconnection. Upon curing of the refractory liner, the tubular sleeves are removed from the refractory liner to yield the plurality of airflow nozzles used to supplement the delivery of air into the combustion zone.

The refractory liner of a combustion chamber is subjected to various forms of attack which can compromise its integrity. In particular, a combustion cell utilized to incinerate wood-based products continuously subjects the refractory liner to heat, abrasion, and alkali attack. These various factors often cause the refractory liner to degrade over time, resulting in a number of harmful effects.

As a first effect, degradation of the refractory liner can change the geometry of the airflow nozzles, resulting in nozzles becoming blocked with ash and constricting, or even reversing, the designated airflow. As a consequence, combustion often becomes stifled and airflow velocity increases which, in turn, produces refractory liner abrasion and creates unbalanced combustion within the interior cavity that can accelerate degradation in the liner in certain areas.

As a second effect, degradation of the refractory liner, particularly due to alkali attack caused by the combustion of wood, can result in its destabilization, since the expanded metal backbone only affords limited structural support to the liner. Structural destabilization of the refractory liner renders it increasingly susceptible to cracking and expansion-related failure, often rendering a combustion chamber inoperable until the refractory liner is suitably repaired or completely replaced.

As a third effect, degradation of the refractory liner exposes the expanded metal support to a greater amount of heat. Because thermal expansion of the metal support occurs at a greater rate than the refractory lining, the combustion chamber is rendered more susceptible to accelerated failure.

SUMMARY OF THE INVENTION

In view thereof, it is an object of the present invention to provide a novel combustion chamber for the incineration of waste products.

It is another object of the present invention to provide a combustion chamber of the type as described above which is durable and experiences minimal material degradation.

It is yet another object of the present invention to provide a combustion chamber of the type as described above which is designed to deliver a uniform and balanced supply of air in order to combust waste products in an efficient manner.

It is still another object of the present invention to provide a combustion chamber of the type as described above which is inexpensive to manufacture, can be installed with great precision, and is easy to maintain.

Accordingly, as one feature of the present invention, there is provided a combustion chamber for the incineration of waste products, the combustion chamber comprising (a) an outer protective wall, and (b) an inner refractory wall extending within the outer protective wall, the inner refractory wall being shaped to define an interior cavity, (c) wherein the inner wall comprises a plurality of precast, refractory blocks.

Various other features and advantages will appear from the description to follow. In the description, reference is made to the accompanying drawings which form a part thereof, and in which is shown by way of illustration, an embodiment for practicing the invention. The embodiment will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, wherein like reference numerals represent like parts:

FIGS. 1(a) and 1(b) are front perspective and front plan views, respectively, of a combustion chamber constructed according to the teachings of the present invention, the combustion chamber being shown in longitudinal cross-section to illustrate certain novel features relating to its construction;

FIG. 1(c) is a simplified top section view of the combustion chamber shown in FIG. 1(b), taken along lines 1(c)-1(c);

FIG. 2 is a top perspective view of a precast block set utilized in the assembly of the inner refractory wall shown in FIG. 1(a);

FIGS. 3(a)-(c) are inner perspective, right end perspective, and top plan views, respectively, of the long refractory block shown in the precast block set of FIG. 2;

FIG. 3(d) is a section view of the long refractory block shown in FIG. 3(c), taken along lines 3(d)-3(d);

FIGS. 4(a) and 4(b) are inner perspective and top plan views, respectively, of the short refractory block shown in the precast block set of FIG. 2;

FIG. 4(c) is a section view of the short refractory block shown in FIG. 4(b), taken along lines 4(c)-4(c);

FIGS. 5(a) and 5(b) are inner perspective and top plan views, respectively, of the short refractory block shown in the precast block set of FIG. 2;

FIG. 5(c) is a section view of the short refractory block shown in FIG. 5(b), taken along lines 5(c)-5(c);

FIGS. 6(a)-6(c) are inner, right end perspective. Inner, left end perspective, and outer, right end perspective views, respectively, of the tuyere refractory block shown in the precast block set of FIG. 2;

FIGS. 6(d) and 6(e) are longitudinal and lateral section views, respectively, of the tuyere refractory block shown in FIG. 6(a), the figures being shown in section to illustrate the shape and orientation of the tuyere hole;

FIG. 7 is a top perspective view of the tieback refractory block shown in the precast block set of FIG. 2, the tieback refractory block being shown exploded form with a tie-back anchor and a support tube;

FIG. 8 is a lateral section view of the tieback refractory block shown in FIG. 7, the tieback refractory block being shown welded to the support tube by the tie-back anchor;

FIG. 9 is an enlarged, fragmentary view of the inner refractory wall shown in FIG. 1(c); and

FIG. 10 is an enlarged, fragmentary, longitudinal section view of two layers of the inner refractory wall shown in FIG. 1(a).

DETAILED DESCRIPTION OF THE INVENTION

Combustion Chamber 11

Referring now to FIGS. 1(a), 1(b), and 1(c), there is shown a combustion chamber designed for the incineration of waste products, the combustion chamber being constructed according to the teachings of the present invention and identified generally by reference numeral 11. As will be explained further in detail below, combustion chamber 11 is constructed, in part, using a plurality of precast, modular, refractory blocks which are stacked and arranged with great precision to create an inner refractory wall which is durable, experiences minimal material degradation, and delivers a uniform and balanced supply of air for incineration.

In the description that follows, combustion chamber 11 is referenced as being primarily designed for use in the incineration of wood-based waste products. However, it should be noted that the present invention is not limited for use in the incineration of wood-based waste products. Rather, it is to be understood that the principles of the present invention could be similarly applied to combustion chambers used in the incineration of a variety of different types of waste products.

As can be seen, combustion chamber 11, also referred to herein interchangeably as combustion cell 11 or combustion unit 11, is constructed as an enlarged, tower-like structure which includes an inner refractory wall 13 which extends vertically within an outer protective wall, or frame, 15. Inner wall 13 is spaced slightly in from outer wall 15 so as to define a plenum 17 therebetween. As will be explained further below, plenum 17 is provided to allow for the delivery of air used in the incineration process.

Inner refractory wall 13 is shaped to define an enlarged, generally cylindrical interior cavity, or combustion zone, 19. Inner wall 13 is additionally shaped to define an opening, or gas outlet, 21 at the top of interior cavity 19 to allow for the escape of heat generated during incineration. Although not limited to any particular application, it is to be understood that heat exiting through opening 21 may be utilized for one or more designated purposes, such as wood drying treatments.

A combustion grate 23 is mounted on inner refractory wall 13 at the bottom of interior cavity 19. Grate 23 is designed to support the waste products intended for incineration and is preferably constructed of a suitable material, such as a water-cooled metal. A door-enclosable access port 25, approximately 19 inches in height, is formed in inner wall 13 proximate grate 23 to allow for the periodic cleaning, maintenance, and/or repair of the interior of combustion unit 11 when not in active operation.

Combustion chamber 11 is provided with an externally-accessible delivery chute 27 which penetrates through inner and outer walls 13 and 15 at a downward angle and into communication with combustion zone 19. A rotatable worm drive 29 is disposed within delivery chute 27. As can be appreciated, waste products are preferably deposited into chute 27 through enlarged exterior opening 27-1 and delivered by worm drive 29 into interior cavity 19 for subsequent incineration.

In use, intense heat, often in excess of 1000° C., is applied in the region directly above grate 23, this region being referenced herein as reactive fuel bed 31. To accelerate incineration, a uniform and balanced supply of air is preferably delivered into combustion zone 19. A primary supply of air used to fuel combustion is delivered upward through grate 23 from a cylindrical air space 33 located directly beneath grate 23, space 33 being in direct communication with plenum 17. A secondary supply of air used to fuel combustion is preferably delivered into interior cavity through a plurality of airflow nozzles, or tuyere holes, 35 which are formed in an optimal configuration within inner refractory wall 13 to ensure balanced airflow delivery, the particular details of tuyere holes 35 to be described in detail further below.

As can be appreciated, the unique construction of inner refractory wall 13 provides construction chamber 11 with a number of notable advantages over traditional combustion cells. Most notably, inner refractory wall 13 of combustion chamber 11 is constructed, in part, using a refractory block set 101 of the type as shown in FIG. 2. As can be seen, refractory block set 101 is comprised of multiple varieties of modular, refractory blocks, which can be selected and stacked in a predefined arrangement to construct inner wall 13. As can be appreciated, the precast and modular nature of the refractory blocks in set 101 serves not only to facilitate assembly and, if necessary, replacement but also to ensure construction with great accuracy and precision, particularly with respect to the location, geometric shape and angle of orientation of tuyere holes 35, which is a principal object of the present invention.

Refractory Block Set 101

As seen in FIG. 2, refractory block set 101 is shown comprising a long refractory block 111, a short refractory block 131, a medium-length refractory block 151, a tuyere refractory block 171 and a tieback refractory block 191. As can be appreciated, blocks 111, 131, 151, 171, and 191 serve as the foundational pieces, or building blocks, which are selected and arranged into stacked circular levels to form uniform inner wall 13.

It should be noted that the particular number and arrangement of each of blocks 111, 131, 151, 171, and 191 are preferably selected by an engineer based on the desired dimensions of inner wall 13 as well as the intended application. Accordingly, the particular arrangement of blocks 111, 131, 151, 171, and 191 shown in combustion chamber 11 is provided for illustrative purposes only and modifications could be readily implemented thereinto without departing from the spirit of the present invention.

Additionally, it should be noted that refractory block set 101 could include additional modular refractory blocks designs, not shown herein, without departing from the spirit of the present invention. As can be appreciated, the greater number of available refractory block shapes and styles serves to enhances the flexibility in optimizing the configuration of inner refractory wall 13.

Referring now to FIGS. 3(a)-(c), long refractory block 111 is shown in greater detail. As can be seen, refractory block 111 is precast as a unitary, modular component. Preferably, block 111 is precast using any suitable heat-resistant material, such a concrete mixture. As can be appreciated, the precast construction of block 111 ensures dimensional accuracy as well as material consistency (e.g., eliminating the presence of bubbles), which is not readily obtainable in traditional cast-in-place constructions.

Block 111 is solid, brick-like member with a slight, yet consistent, radial curvature and includes a flat top surface 113, a flat bottom surface 115, an arcuate inner surface 117, an arcuate outer surface 119, a flat left end surface 121, and a flat right end surface 123. Dimensionally, block 111 preferably has a uniform width W₁ of approximately 9 inches, a uniform height H₁ of approximately 6.4375 inches, and extends in length along an arc A₁ of approximately 20 degrees to yield an inner arc length L_I1 of approximately 11.375 inches and an outer arc length L_O1 of approximately 14.5 inches. However, it is to be understood that the block 111 is not limited to the aforementioned dimensions and could be resized, as needed, without departing from the spirit of the present invention.

A projection 125, semi-circular in transverse cross-section, protrudes upward from top surface 113 along its centerline. Additionally, a recess 126, semi-circular in transverse cross-section, is formed in bottom surface 115 along its centerline. Both projection 125 and recess 126 have a radius of approximately 1 inch and thereby serve as complementary surface mating features, as will be described further below.

Projection 125 extends along the majority of the length of block 111, with projection 125 extending just beyond left end surface 121 to form a tongue 127. Tongue 127 extends vertically across left end surface 121 and is generally semi-circular in cross-section, as seen most clearly in FIG. 3(c). A complementary groove 129, generally semi-circular in cross-section extends vertically in right end surface 123, with groove 129 having the same radius as tongue 127.

In this manner, it is to be understood that multiple blocks 111 are adapted to be stacked directly upon one another, with projection 125 of a lower block 111 protruding into recess 126 in an upper, or stacked, block 111. In this manner, this interlocking arrangement between projection 125 and recess 126 serves not only to facilitate proper registration between a stacked pair of blocks 111 but also to provide structural support and thereby minimize the risk of inner wall destabilization over time.

Similarly, it is to be understood that multiple blocks 111 are adapted to be configured in an end-to-end relationship, with tongue 127 of one block 111 protruding into groove 129 in an adjacent, or neighboring, block 111. This interlocking arrangement between tongue 127 and groove 129 also serves to facilitate proper registration between an adjacent pair of blocks 111 and provide structural support to inner refractory wall 13, which is highly desirable.

As referenced above, the dimensions of block 111 could be readily modified without departing from the spirit of the present invention. Most notably, arc A₁ of block could be adjusted to provide the designer of inner refractory wall 13 with greater flexibility in its structural configuration.

As an example, in FIGS. 4(a)-(c), short refractory block 131 is shown in greater detail. As can be seen, short refractory block 131 is identical to refractory block 111 in that short refractory block 131 is precast as a unitary, modular component using any suitable heat-resistant material, such a concrete mixture.

Refractory block 131 is also identical to refractory block 111 in that refractory block 131 is constructed as solid, brick-like member with a slight, yet consistent, radial curvature and includes a flat top surface 133, a flat bottom surface 135, an arcuate inner surface 137, an arcuate outer surface 139, a flat left end surface 141, and a flat right end surface 143.

As further similarities, a projection 145, semi-circular in transverse cross-section, protrudes upward from top surface 133 along its centerline and mates with a semi-circular recess 146 formed in bottom surface 135 along its centerline. Additionally, a tongue 147, semi-circular in transverse cross-section, extends vertically across left end surface 141 and mates with a complementary groove 149 extending vertically in right end surface 143.

Refractory block 131 only differs from refractory block 111 in its dimensions. Although refractory block 131 has a uniform width W₂ of approximately 9 inches, which is identical to refractory block 111, and a uniform height H₂ of approximately 6.4375 inches, which is identical to refractory block 111, refractory block 131 is considerably shorter in length than refractory block 111.

Notably, refractory block 131 extends in length along an arc A₂ of approximately 10 degrees to yield an inner arc length Lie of approximately 5.6875 inches and an outer arc length L_O2 of approximately 7.25 inches. As such, refractory block 131 is one-half the length of refractory block 111.

As another example, in FIGS. 5(a)-(c), medium-length refractory block 151 is shown in greater detail. As can be seen, medium refractory block 151 is identical to refractory block 111 in that medium refractory block 151 is precast as a unitary, modular component using any suitable heat-resistant material, such a concrete mixture.

Refractory block 151 is also identical to refractory block 111 in that refractory block 151 is constructed as solid, brick-like member with a slight, yet consistent, radial curvature and includes a flat top surface 153, a flat bottom surface 155, an arcuate inner surface 157, an arcuate outer surface 159, a flat left end surface 161, and a flat right end surface 163.

As further similarities, a projection 165, semi-circular in transverse cross-section, protrudes upward from top surface 153 along its centerline and mates with a semi-circular recess 166 formed in bottom surface 155 along its centerline. Additionally, a tongue 167, semi-circular in transverse cross-section, extends vertically across left end surface 141 and mates with a complementary groove 169 extending vertically in right end surface 163.

Refractory block 151 only differs from refractory block 131 in its dimensions. Although refractory block 151 has a uniform width W₃ of approximately 9 inches, which is identical to refractory block 111, and a uniform height H₃ of approximately 6.4375 inches, which is identical to refractory block 111, refractory block 151 is considerably shorter in length than refractory block 111 but greater in length than refractory block 131.

Notably, refractory block 151 extends in length along an arc A₃ of approximately 16 degrees to yield an inner arc length L_I3 of approximately 9.125 inches and an outer arc length L_O3 of approximately 11.625 inches. As such, the length of refractory block 151 lies between the lengths of refractory blocks 111 and 131.

Referring now to FIGS. 6(a)-(e), tuyere refractory block 171 is shown in greater detail. As will be explained further in detail below, each block 171 is precast to define a single tuyere hole, or airflow nozzle, 31. Due to the precast nature of block 171, the exact position, dimensions, and angle of orientation of airflow nozzle 31 can be ensured with great precision. As a result, combustion cell 11 is more effective in sustaining efficient and balanced combustion of waste products.

By contrast, the conventional practice of creating tuyere holes by ramming and subsequently removing cylindrical sleeves into a one-piece, curable, refractory lining has been found to be difficult to implement with great precision. As a result, airflow nozzles are often arranged and formed in conventional refractory linings with widespread variances and inconsistencies, which is highly undesirable.

As can be seen, tuyere refractory block 171 is identical to refractory block 111 in that refractory block 171 is precast as a unitary, modular component using any suitable heat-resistant material, such a concrete mixture.

Refractory block 171 is also identical to refractory block 111 in that refractory block 171 is constructed as solid, brick-like member with a slight, yet consistent, radial curvature and includes a flat top surface 173, a flat bottom surface 175, an arcuate inner surface 177, an arcuate outer surface 179, a flat left end surface 181, and a flat right end surface 183.

As further similarities, a projection 185, semi-circular in transverse cross-section, protrudes upward from top surface 173 along its centerline and mates with a semi-circular recess 186 formed in bottom surface 175 along its centerline. Additionally, a tongue 187, semi-circular in transverse cross-section, extends vertically across left end surface 181 and mates with a complementary groove 189 extending vertically in right end surface 183.

The exterior dimensions of refractory block 171 are also identical to refractory block 111. In fact, block 171 only differs from refractory block 111 in its inclusion of tuyere hole 31. As can be seen, tuyere hole 171 is in the form of a tubular bore with a circular cross-section of uniform diameter D along its length, diameter D preferably being approximately 1.375 inches.

Tuyere hole 31 is designed to extend in a downward and right-to-left direction from outer surface 179 to inner surface 177, with one end 31-1 located in the corner of outer surface 179 proximate top surface 173 and right end surface 183 and the other end 31-2 located in the corner of inner surface 177 proximate bottom surface 175 and left end surface 181. Preferably, tuyere hole 31 is pitched so as to extend at a downward angle Θ₁ of approximately 15 degrees and a right-to-left, or horizontal, angle Θ₂ of approximately 45 degrees. As can be appreciated, the dimension and orientation of tuyere hole 31 is optimized to deliver an efficient and balanced airflow supply into combustion zone 19.

Referring now to FIGS. 7 and 8, tieback refractory block 191 is shown in greater detail. As will be explained further in detail below, each tieback block 191 is uniquely designed to facilitate its securement to a fixed support structure. As a result, the inclusion and fixed securement of tieback blocks 191 provides anchored structural support to inner wall 13 so as to minimize the risk of destabilization over time.

As can be seen, tieback refractory block 191 is identical to refractory block 111 in that tieback refractory block 191 is precast as a unitary, modular component using any suitable heat-resistant material, such a concrete mixture.

Tieback refractory block 191 is also identical to refractory block 111 in that refractory block 191 is constructed as solid, brick-like member with a slight, yet consistent, radial curvature and includes a flat top surface 193, a flat bottom surface 195, an arcuate inner surface 197, an arcuate outer surface 199, a flat left end surface 201, and a flat right end surface 203.

As further similarities, a projection 205, semi-circular in transverse cross-section, protrudes upward from top surface 193 along its centerline and mates with a semi-circular recess 206 formed in bottom surface 195 along its centerline. Additionally, a tongue 207, semi-circular in transverse cross-section, extends vertically across left end surface 201 and mates with a complementary groove 209 extending vertically in right end surface 203.

The exterior dimensions of refractory block 191 are also largely identical to refractory block 111. However, block 191 differs from refractory block 111 in that block 191 is shaped to include an external groove, or recess, 211 which is suitably dimensioned to receive an L-shaped tie-back 213. As will be explained further below, tie-back 213 is designed for fixed securement to a support structure in order to stabilize inner wall 13.

As can be seen, external groove 211 is generally circular in transverse cross-section and has a uniform diameter of approximately 0.5 inches. External groove 211 is generally L-shaped and includes (i) a horizontal portion 211-1 formed in top surface 193 which extends radially inward from outer surface 199 at its approximate midpoint, and (ii) a vertical portion 211-2 which extends orthogonally downward from the inner end of horizontal portion 211-1, vertical portion 211-2 extending down from top surface 193 towards bottom surface 195 for a depth of approximately 3 inches.

External groove 211 in block 191 is designed to retain a corresponding tie-back anchor, or tie-back, 213. Tie-back 213 is constructed as a unitary, L-shaped rod constructed of a rigid and durable material, such as stainless steel. In the present embodiment, tie-back 213 has a uniform diameter of 0.5 inches and includes a horizontal segment 213-1 and a vertical segment 213-2 extending at a right angle.

As shown in FIG. 8, tie-back 213 is designed for fitted insertion in external groove 211, with horizontal segment 213-1 of tie-back 213 lying within horizontal portion 211-1 in block 191 and vertical segment 213-2 of tie-back 213 projecting within vertical portion 211-2 in block 191. Mounted into engagement as such, the distal end of horizontal segment 213-1 of tie-back 213 protrudes beyond outer surface 199 of block 191.

A vertical support tube 221 extending in abutment against outer surface 199 of block 191. In the present embodiment, tube 221 is represented as an elongated tubular member, constructed of a rigid and durable material, with a 2-inch square shape in transverse cross-section. As a feature of the invention, the distal end of tie-back 213 preferably aligns flush against a side surface of tube 211. Therefore, by directly welding tie-back 213 to side surface of tube 211, block 191 (and effectively all other blocks connected thereto) is provided rigid anchored support from tube 221.

Design and Assembly of Inner Wall 13

Referring back to FIGS. 1(a)-(c), inner wall 13 of combustion chamber 11 is preferably constructed, at least in part, in the following manner. First, prior to assembly, a plurality of support tubes 221 are arranged in a circular configuration so as to define the outer diameter of inner wall 13. Tubes 221 extend vertically and are preferably welded, or otherwise fixedly secured to, outer wall 15.

As seen most clearly in FIG. 1(c), tubes 221 are preferably spaced evenly apart from one another so as to provide uniform support for inner wall 13. In the present embodiment, eighteen tubes 221 are spaced apart at 20-degree intervals. As such, the requisite number of evenly-spaced tieback blocks 191 in each layer (e.g. nine tieback blocks 191) is able to anchor onto a corresponding set of tubes 221.

With support tubes 221 installed, the design of inner wall 13 is formulated using refractory block set 101. The particular selection and arrangement of blocks 111, 131, 151, 171, and 191 utilized to construct inner wall 13 as a complete sealed ring are determined based on, inter alia, the desired dimensions, structural needs, and airflow requirements of combustion unit 11.

Once design of inner wall 13 is formulated, the selection of refractory blocks from set 101 are stacked, layer by layer, in the predetermined arrangement, with the interlocking mating faces of adjacent refractory blocks not only facilitating proper registration but also providing enhanced structural support, as shown in FIGS. 9 and 10. The four-sided interlocking of each refractory block with its neighboring blocks also enables the interior surface of inner wall 13 to wear away by nearly half of its thickness without disruption to the intermating feature established between adjacent surfaces. As part of the assembly process, all other essential components of combustion unit 11 (e.g., outlet 21, grate 23 access port 25, chute 27) are properly integrated into inner wall 13 during the stacking of the selection of refractory blocks 111, 131, 151, 171 and/or 191.

Preferably, a refractory mortar (not shown) is preferably applied in the joint, or spacing, between adjacent blocks for bonding purposes in order to create a uniform interior surface and ensure structural integrity. Preferably, a thin, uniform layer of the mortar (e.g., approximately 0.0625 inches in thickness) is applied to effectuate bonding without distorting proper positioning.

Ideally, a predefined number of tieback blocks 191 are utilized in each layer, with variability in the location and/or number of tieback blocks 191 created through selection amongst the different lengthened blocks 111, 131 and 151. Tieback blocks 191 are therefore preferably arranged for welding to corresponding tubes 221 by tie-backs 213. As a feature of the invention, the welding of tieback blocks 191 to support tubes 221 eliminates the need for the expanded metal support utilized in traditional combustion units and thereby remedies the various shortcomings associated therewith.

As seen in FIG. 1(c), each layer of inner wall 13 preferably secures a tieback block 191 to a first set of alternating (i.e. every other) support tubes 221, with adjacent layers of wall 13 preferably securing a tieback block 19 to the remaining (i.e. second set) of alternating support tubes 221. In this fashion, support to inner wall 13 is uniformly distributed.

Additionally, a predefined number of tuyere blocks 171 is preferably utilized and equidistantly arranged in each layer to provide the necessary secondary airflow required to optimize combustion within interior cavity 19. By ensuring balanced and efficient combustion within unit 11, any degradation of inner wall 13 is greatly minimized. Furthermore, because blocks 171 are precast, the shape and dimension of each tuyere hole 31 is formed with considerable precision.

As can be appreciated, the construction of inner wall 13 using a plurality of precast refractory blocks improves its overall structural integrity and manufacturing precision. As an additional benefit, the modular nature of inner wall 13 allows for sections thereof to be simply and easily restored using replacement refractory blocks, as needed.

The invention described in detail above is intended to be merely exemplary and those skilled in the art shall be able to make numerous variations and modifications to it without departing from the spirit of the present invention. All such variations and modifications are intended to be within the scope of the present invention as defined in the appended claims.

Claims

1. A combustion chamber for the incineration of waste products, the combustion chamber comprising: (a) an outer protective wall; and(b) an inner refractory wall extending within the outer protective wall, the inner refractory wall being shaped to define an interior cavity;(c) wherein the inner wall comprises a plurality of precast, refractory blocks.

2. The combustion chamber of claim 1 wherein the inner refractory wall is spaced in from the outer protective wall so as to define a plenum therebetween.

3. The combustion chamber of claim 2 wherein the plurality of precast, refractory blocks is stacked in layers and together, at least in part, define the interior cavity.

4. The combustion chamber of claim 3 wherein the plurality of precast, refractory blocks matingly engages one another when stacked in layers.

5. The combustion chamber of claim 3 wherein each of the plurality of precast, refractory blocks comprises a top surface, a bottom surface, an inner surface, an outer surface, a left end surface and a right end surface.

6. The combustion chamber of claim 5 wherein the inner surface for each of the plurality of precast, refractory blocks has a fixed radial curvature.

7. The combustion chamber of claim 5 wherein a projection is formed on the top surface of each of the plurality of precast, refractory blocks.

8. The combustion chamber of claim 7 wherein a recess is formed on the bottom surface of each of the plurality of precast, refractory blocks.

9. The combustion chamber of claim 8 wherein the recess on one of the plurality, of precast, refractory blocks is dimensioned to fittingly receive the projection on another of the plurality of precast, refractory blocks when arranged in a stacked relationship.

10. The combustion chamber of claim 5 wherein a tongue extends out from one of the left end surface and the right end surface of each of the plurality of precast, refractory blocks.

11. The combustion chamber of claim 10 wherein a groove is formed in the other of the left end surface and the right end surface of each of the plurality of precast, refractory blocks.

12. The combustion chamber of claim 11 wherein the groove on one of the plurality, of precast, refractory blocks is dimensioned to fittingly receive the tongue on another of the plurality of precast, refractory blocks when arranged in an end-to-end relationship.

13. The combustion chamber of claim 5 wherein at least two of the plurality of precast, refractory blocks differ in length.

14. The combustion chamber of claim 5 wherein at least one of the plurality of precast, refractory blocks is shaped to define a tuyere hole.

15. The combustion chamber of claim 14 wherein the tuyere hole is circular in transverse cross-section.

16. The combustion chamber of claim 15 wherein the tuyere hole extends downward and horizontally from the outer surface to the inner surface.

17. The combustion chamber of claim 5 further comprising a vertical support tube fixedly coupled to the outer protective wall.

18. The combustion chamber of claim 17 wherein at least one of the plurality of precast, refractory blocks is secured the vertical support tube with a tie-back anchor.

19. The combustion chamber of claim 18 wherein the at least one of the plurality of precast, refractory blocks is shaped to define a groove which is dimensioned to fittingly receive at least a portion of the tie-back anchor.