Housing for a pulverizer system and a pulverizer system

Abstract

The present invention discloses a housing of a pulverizer system, the housing comprising a generally cylindrical body forming an inner cavity having a central axis, a cover positioned above the cylindrical body, and a bottom plate positioned within the inner cavity of the cylindrical body and opposite to the cover, the bottom plate having a surface extending from a point closest to the central axis to an inner side wall of the cylindrical body. The surface of the bottom plate has a substantially constant radius of curvature.

Description

Technical Field

[0001] Embodiments of the present invention relate to pulverizer systems, and more particularly, to a grind side configuration for a pulverizer system that reduces operating stresses on the grind side of the pulverizer system. Background Art

[0002] Discussion of the field

[0003] Vertical pulverizer systems are used to process raw materials to be used by various power generation systems. For example, a conventional vertical pulverizer system can grind coal into fine particles. The fine coal particles produced by the vertical pulverizer system can be used by the boiler of a steam turbine system configured to generate electricity. Conventional vertical pulverizers generally include a grinding mechanism positioned within a sealed chamber that can grind or press the raw materials to form fine particles.

[0004] During the pulverizing process performed by the vertical mill system, the chamber and the components positioned within the chamber may experience various stresses. For example, due to the need for the grinding mechanism to apply sufficient pressure to grind the raw material, pressure loads may form or grow within the chamber. Additionally, in some cases, the raw material may be combustible (e.g., coal). Therefore, the chamber of the vertical mill system may also experience explosion loads. Furthermore, due to starting and stopping the grinding process, the chamber will experience large swings in thermal loads and / or temperature. Additionally, due to the mechanical loads required to grind the raw material within the vertical mill system, the chamber and / or the components within the chamber may experience large mechanical loads.

[0005] Regulatory codes, such as the National Fire Protection Association (NFPA) code, specify maximum allowable stresses for all parts of a pulverizer under a combination of normal grinding loads, thermal loads, and an internal pressure of 50 psi. In order to compensate for these relatively high loads (e.g., thermal, mechanical, pressure) and meet established standards, chambers are typically constructed from a variety of different components formed from very thick metals. These conventional chamber sizes are typically large, including various connection nodes (e.g., welds between components) and angle transitions between surfaces and / or components that form the chamber.

[0006] Although most conventional chambers are constructed to withstand the stresses or loads experienced, conventional chambers include areas of high stress concentration that experience loads exceeding other portions of the chamber. For example, during operation of a vertical mill system, angular transitions between portions and / or components of a conventional chamber experience greater or more concentrated stresses and / or loads. These areas may include portions of the air intake duct and the grinding side floor.

[0007] For example, Figure 1The configuration of the intake duct 12 of a prior art shredder system 10 is shown. As shown therein, the intake duct 12 has a rectangular cross-section. However, the corners of the duct 12 create high stress concentrations that require significant reinforcement at the connection of the intake duct and the grinding side shell 26 in order to meet established regulatory standards during operation. Such reinforcements can be in the form of a layer (i.e., an added patch of material) around the boundary of the intake duct (e.g., at area 14). Such reinforcements can also be in the form of a web material on the interior of the intake duct 12, at the inside corners of the sides 16 connecting the duct 12. However, the need for thicker material or corner reinforcements can significantly increase the material and labor costs of the manufacturing process.

[0008] Figure 2 The configuration of the grinding side floor plate 20 of the prior art pulverizer system 10 is shown. As is common in the industry, the floor plate 20 has a quasi-spherical geometry that includes a spherical portion 22 having a fixed radius and an annular knuckle 24 that forms a transition between the spherical portion 22 and the cylindrical side wall 26 of the chamber. Such a quasi-spherical floor plate is difficult to manufacture while providing satisfactory pressure containment and may include a high stress concentration area A where the floor plate 20 connects to the chamber side wall / shell 26. Figure 3 is shown at the quasi-spherical head / ground side shell connection ( Figure 2 Finite element analysis of relative thermal stresses in region A), where higher stresses are indicated by darker shaded areas.

[0009] In view of the foregoing, there is a need for a pulverizer system having an intake duct geometry and a grind side floor geometry that meets established regulatory standards and minimizes the need for thicker material and reinforcements in areas that typically experience high stress concentrations. Summary of the invention

[0010] In an embodiment, a housing of a pulverizer system is provided. The housing includes a generally cylindrical body forming an inner cavity having a central axis, a cover positioned above the cylindrical body, and a bottom plate positioned within the inner cavity of the cylindrical body and opposite to the cover, the bottom plate having a surface extending from a point closest to the central axis to an inner side wall of the cylindrical body. The surface of the bottom plate has a substantially constant radius of curvature.

[0011] In another embodiment, a housing of a pulverizer system is provided. The housing includes: a generally cylindrical body forming an inner cavity having a central axis; a cover positioned above the cylindrical body; a bottom plate positioned within the inner cavity of the cylindrical body and opposite the cover; an air inlet opening formed through the cylindrical body, the air inlet opening being positioned above the bottom plate; and an air inlet duct substantially surrounding the air inlet opening, the air inlet duct having a curved end and no sharp corners.

[0012] In yet another embodiment, a pulverizer system is provided. The pulverizer system includes a housing having: a generally cylindrical body forming an inner cavity having a central axis; a cover positioned above the cylindrical body; a bottom plate positioned within the inner cavity of the cylindrical body and opposite to the cover, the bottom plate having a surface extending from a point closest to the central axis to an inner side wall of the cylindrical body, the bottom plate having a substantially constant radius of curvature; an air inlet opening formed through the cylindrical body, the air inlet opening being positioned above the bottom plate; and an air inlet duct substantially surrounding the air inlet opening, the air inlet duct having an elliptical cross-section. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be better understood by reading the following description of non-limiting embodiments with reference to the accompanying drawings, in which:

[0014] Figure 1 is a perspective view of a prior art pulverizer system showing the conventional rectangular air intake duct.

[0015] Figure 2 yes Figure 1 A cross-sectional view of a prior art pulverizer system showing a conventional quasi-spherical base plate.

[0016] Figure 3 is a finite element analysis showing the relative thermal stresses at the quasi-spherical base plate / ground side shell connection.

[0017] Figure 4 is a perspective view of a housing of a vertical mill system according to an embodiment of the present invention.

[0018] Figure 5 yes Figure 4 A cross-sectional perspective view of the housing of a vertical mill system.

[0019] Figure 6 yes Figure 4 An enlarged perspective view of a portion of a vertical mill system showing its air intake duct.

[0020] Figure 7 yes Figure 4A cross-sectional view of a portion of a vertical mill system showing its bottom plate.

[0021] Figure 8 yes Figure 4 An enlarged cross-sectional view of a portion of a vertical pulverizer system showing the configuration of the bottom plate and the intersection between the bottom plate and the side walls of the housing of the pulverizer system.

[0022] Fig. 9 It is shown by Figure 6 Finite element analysis of the relative stresses experienced by the intake duct.

[0023] Fig.10 is a finite element analysis showing the relative stresses at the ball disc base plate / grind side housing connection. DETAILED DESCRIPTION

[0024] Reference will be made in detail to exemplary embodiments of the present invention, examples of which are shown in the accompanying drawings. Whenever possible, the same reference numerals used throughout the accompanying drawings refer to the same or similar parts. The following disclosure generally relates to a grinder system, and more specifically to a housing of a vertical grinder system. As used herein, "grinding side" refers to the portion of the grinder housing between the height of the grinding surface and the base. As used herein, "fluid coupling" or "fluid communication" refers to the arrangement of two or more features so that the features are connected in a manner that allows fluid to flow between the features and allows fluid transfer.

[0025] Figure 4 and Figure 5 Various views of a housing or casing 100 of a vertical mill system according to an embodiment of the present invention are shown. The housing or casing 100 may be referred to herein as a "mill system" even though the gearbox, grinding wheel, and other internal components are omitted from the figures. As shown therein, the casing 100 includes a cylindrical body 102. The cylindrical body 102 may be oriented vertically and may include substantially linear walls. As shown and discussed herein, the cylindrical body 102 may form an interior cavity 104 (see Figure 5 ), and can substantially contain and / or surround the housing 100 and / or various components of the vertical mill system. Figure 4 and Figure 5In the non-limiting example shown, the cylindrical body 102 can include at least two different parts. Specifically, the cylindrical body 102 can include an upper portion 106 and a lower portion or bowl portion 108 positioned below the upper portion 106 and / or coupled to the upper portion. Although two parts are shown, it should be understood that the cylindrical body 102 can be formed by more different parts. In another non-limiting example, the cylindrical body 102 can be formed by a single component or material piece. The cylindrical body 102 of the housing 100 can be formed by any material that can withstand pressure changes, offsets, mechanical stresses and / or temperature changes, which may be experienced during the operation of the vertical mill system, as discussed herein. In a non-limiting example, the cylindrical body 102, and specifically the upper portion 106 and the bowl portion 108 can be formed by metal and / or metal alloys. Additionally, the cylindrical body 102 of the housing 100 may be formed using any suitable material forming process or technique, including but not limited to rolling, casting, forming, and / or the like.

[0026] like Figure 4 and Figure 5 As further shown, the housing 100 may also include a plurality of legs 110. The legs 110 may be positioned below the cylindrical body 102 and may extend perpendicularly to the cylindrical body 102. Figure 4 and Figure 5 In the non-limiting example shown, the foot 110 can be a distinct component from the cylindrical body 102 and can be coupled to the bottom of the bowl portion 108 of the cylindrical body 102. In another non-limiting example, the foot 110 can be integrally formed with the cylindrical body 102 and can be formed and / or shaped to extend perpendicular to the cylindrical body 102. As discussed herein, the foot 110 can be coupled to a support of a vertical mill system using the housing 100 to support the housing 100 and various components of the system positioned within the housing 100.

[0027] The housing 100 may further include a cover 112 positioned above the cylindrical body 102. The cover 112 may be coupled to the cylindrical body 102, and in particular, to the upper portion 106 of the cylindrical body 102. The cover 112 may be coupled to the cylindrical body 102 to substantially close and / or form the inner cavity 104 formed by the cylindrical body 102 of the housing 100 (see Figure 5) closed end. The cover 112 can be coupled to the cylindrical body 102 using any suitable coupling mechanism and / or coupling technology. For example, the cover 112 can be coupled to the cylindrical body 102 using mechanical fasteners (such as bolts), or alternatively, the cover 112 can be welded to the cylindrical body 102. Similar to the cylindrical body 102, the cover 112 can be formed of any material that can withstand pressure changes, offsets, mechanical stresses, and / or temperature changes that may be experienced during the operation of the vertical mill system, as discussed herein. In a non-limiting example, the cover 112 can be formed of a metal and / or a metal alloy. In addition, the cover 112 and the various components or portions of the cover 112 discussed herein can be formed using any suitable material forming process or technology, including but not limited to rolling, casting, forming, and / or similar processes.

[0028] like Figure 5 As best shown, the cover 112 may include a substantially curved, non-linear and / or domed surface 118. Figure 5 In the non-limiting example shown, the curved surface 118 of the cover 112 can be substantially convex relative to the inner cavity 104 of the cylindrical body 102. Specifically, the cover 112 can include an inner curved surface (not shown) facing and / or positioned within the inner cavity 104, which can be substantially convex. The curved surface 118 of the cover 112 can include any non-linear geometry and / or shape, including but not limited to quasi-spherical, hemispherical, ellipsoidal, and any other dome-shaped geometry. The curved surface 118 of the cover 112 can extend completely, completely, or substantially around the perimeter and / or the entirety of the cover 112.

[0029] Various channels may be formed through the cover 112 of the housing 100. That is, the cover 112 may include various channels formed through the top portion 120 of the cover 112. Figure 4 and Figure 5 As shown, the material inlet passage 122 can be formed through the top portion 120 of the cover 112. In a non-limiting example, the material inlet passage 122 can be formed completely through the center (C) of the cover 112, which is also the central axis of the body 102. In addition, the material inlet passage 122 can extend away from the surface of the cover 112 and / or above it. The material inlet passage 122 formed in the cover 112 can be in fluid communication with the inner cavity 104 formed by the cylindrical body 102. As discussed herein, the material inlet passage 122 can be configured within a vertical mill system and / or used within a vertical mill system to provide raw material (e.g., coal) to components of the vertical mill system for processing within the housing 100. In addition, although in Figure 4 and Figure 5112 as being formed through the center (C) of the cover 112, but it should be understood that the material inlet passage 122 may be formed through any portion of the cover 112 to be in fluid communication with the housing 100 and / or provide raw material thereto.

[0030] The cover 112 may also include at least one particle outlet channel 124. The particle outlet channel 124 may be formed completely through the cover 112 so that the particle outlet channel 124 may also be in fluid communication with the inner cavity 104 formed by the cylindrical body 102. The particle outlet channel 124 may be formed through the top portion 120 of the cover 112 adjacent to the material inlet channel 122. Similar to the material inlet channel 122, the particle outlet channel 124 may extend away from the surface of the cover 112 and / or above it. In a non-limiting example, the cover 112 of the housing 100 may include four (4) different particle outlet channels 124 formed therein. The particle outlet channels 124 may substantially surround and may be spaced approximately equidistant from the material inlet channel 122 and from each other, respectively. Although Figure 4 and Figure 6 1 and 2. Four particle outlet passages 124 are depicted in the housing 100, but it should be understood that the number of particle outlet passages 124 shown in the figure is merely illustrative, and the cover 112 may include more or fewer particle outlet passages 124 than depicted and discussed herein. The particle outlet passages 124 may be configured and / or used within a vertical mill system to allow and / or transport processed particles of raw material (e.g., coal) away from the housing 100 to a different power system that may use the vertical mill system.

[0031] like Figure 4 and Figure 6 As best shown, the housing 100 may also include an air inlet opening 126. The air inlet opening 126 may be formed through the cylindrical body 102. Specifically, the air inlet opening 126 may be formed through the bowl portion 108 of the cylindrical body 102. As discussed herein, the air inlet opening 126 may provide a portion of the inner cavity 104 formed by the cylindrical body 102 (see Figure 5 ) and the air system of the vertical mill system. An air intake cover or duct 128 may substantially surround an air intake opening 126 formed through the cylindrical body 102. As shown, the air intake duct 128 may be positioned on and / or coupled to an exposed or outer surface 130 of the cylindrical body 102 and may extend or protrude away from the cylindrical body 102. As discussed herein, the air intake duct 128 may couple the gas system of the vertical mill system to the housing 100 so that the gas system may provide gas (e.g., air) into the housing 100 through the air intake opening 126.

[0032] like Figure 4 and Figure 6As best shown, the cross-section of the intake duct 128 is substantially elliptical or stadium-shaped, having two opposing semi-circular / semi-cylindrical ends 135, 136 and linear / planar top and bottom sides 137, 139 that connect the tangent points of the ends 135, 136. In an embodiment, the intake duct 128 is oriented substantially horizontally. However, it is contemplated that in some embodiments, the cross-section of the intake duct may be round / circular. In yet other embodiments, the intake duct 128 may have arcuate or curved ends and substantially linear / planar sides connecting the opposing ends, and in any embodiment, may not contain sharp corners. In an embodiment, the opening 126 may have a shape that generally corresponds to the cross-sectional shape of the intake duct 128. As shown in FIG. Figure 6 As best shown in FIG. 1 , in certain embodiments, housing 100 may include a single layer 141 of reinforcement around the perimeter of intake duct 128, at the junction of intake duct 128 and cylindrical body / grind side housing 102. In embodiments, no reinforcement layer is required.

[0033] This intake duct configuration eliminates the corners and reinforcements that standard intake ducts have, which are typically required to comply with regulatory codes. In particular, the use of rounded ends instead of sharp corners reduces stress concentrations. This particular configuration is also more robust and has lower manufacturing costs (materials and labor) than conventional rectangular intake ducts.

[0034] Further references Figure 4 and Figure 5 , the housing 100 may further include a journal opening 132 and a journal opening cover 134 that substantially covers the journal opening 132. The journal opening 132 and the journal opening cover 134 may provide an opening, a cover, and / or a support structure for a journal of the vertical mill system, which may be used to process raw materials within the housing 100 during operation of the vertical mill system. The journal opening 132 may be formed through the cylindrical body 102 below the cover 112. In a non-limiting example where the cylindrical body 102 is formed by the upper portion 106 and the bowl portion 108, the journal opening 132 may be formed through a portion of each of the upper portion 106 and the bowl portion 108. Thus, when the upper portion 106 and the bowl portion 108 are coupled together to form the cylindrical body 102, the journal opening 132 may be a single opening and / or hole formed through the cylindrical body 102.

[0035] exist Figure 4 and Figure 5In the non-limiting example shown, the housing 100 can include three different journal openings 132 formed through the cylindrical body 102. However, it should be understood that the number of depicted journal openings 132 formed through the cylindrical body 102 may be exemplary only and may not be considered limiting. As discussed herein, the journal openings 132 formed through the cylindrical body 102 may provide access to the internal cavity 104 formed through the cylindrical body 102 and / or components used by the vertical mill system, which may be positioned within the cylindrical body 102 and substantially pass through and / or be located within the journal openings 132.

[0036] exist Figure 4 and Figure 5 In the non-limiting example shown, the journal opening 132 may include a door 138 configured to provide access to the interior cavity 104 of the cylindrical body 102, a trunnion support 140 positioned adjacent and below the door 138, and a curved sidewall 142 positioned substantially perpendicular to the door 138. The door 138 may be coupled to both the trunnion support 140 and the curved sidewall 142, respectively. In a non-limiting example, the door 138 may be releasably coupled to the trunnion support 140 and / or the curved sidewall 142. Thus, the door 138 may be released, removed, hinged, and / or otherwise uncoupled from the trunnion support 140 and / or the curved sidewall 142 to provide access to the interior cavity 104 and / or components of the vertical mill system positioned within the cylindrical body 102. In other non-limiting examples discussed herein, where components of the vertical mill system are attached and / or coupled to the door 138, the door 138 may be uncoupled and / or hinged to at least partially remove the components of the vertical mill system from the housing 100. Figure 4 and Figure 5 As shown, and as described below, the door 138 may be formed to substantially match or mirror the shape and / or geometry of the journal opening 132 and / or the curved sidewall 142 .

[0037] like Figure 5 As further shown, the housing 100 may also include a base member or a grinding side bottom plate 144. The bottom plate 144 may be positioned within the interior cavity 104 of the cylindrical member 102, opposite the cover 112. Specifically, the bottom plate 144 may be positioned within the bowl portion 108 of the cylindrical body 102, and may be positioned below the upper portion 106, the cover 112, and the journal opening cover 134. Additionally, the bottom plate 144 may be positioned adjacent to and / or below the intake opening 126 formed through the bowl portion 108 of the cylindrical body 102. Figure 5 As shown, the cylindrical body 102 extends below the bottom plate 144, and the cylindrical body 102 may substantially surround the bottom plate 144 such that the bottom plate 144 may not be visible when the housing 100 is assembled.

[0038] like Figure 5 As shown, the bottom plate 144 can be coupled to the inner surface 146 of the cylindrical body 102. The bottom plate 144 can be coupled to the inner surface 146 of the cylindrical body 102 using any suitable coupling mechanism and / or coupling technology. For example, the bottom plate 144 can be coupled to the cylindrical body 102 using mechanical fasteners (such as bolts), or alternatively, the bottom plate 144 can be welded to the cylindrical body 102. Similar to the cylindrical body 102 and / or the cover 112 discussed herein, the bottom plate 144 can be formed of any material that can withstand pressure changes, offsets, mechanical stresses, and / or temperature changes that may be experienced during the operation of the vertical mill system, as discussed herein. In a non-limiting example, the bottom plate 144 can be formed of a metal and / or a metal alloy. The bottom plate 144 can be formed using any suitable material forming process or technology, including but not limited to rolling, casting, forming, and / or similar processes.

[0039] Special References Figure 7 and Figure 8 , compared to existing pulverizer systems, the bottom plate 144 of the housing / pulverizer system 100 has a spherical or hemispherical rather than quasi-spherical surface 148 and does not contain any knuckles or transitions of different radii connecting the bottom plate 144 to the inner surface / sidewall 146 of the housing. The spherical surface 148 of the bottom plate 144 can be substantially concave relative to the inner cavity 104 of the cylindrical body 102. Similar to the curved surface 118 of the cover 112, the surface 148 of the bottom plate 144 can extend completely, completely or substantially around the perimeter and / or the entirety of the bottom plate 144. As discussed herein, the geometry and / or shape of the surface 148 of the bottom plate 144 can help and / or improve the effects of temperature changes, airflow and / or pressure restrictions within the housing 100 during operation of a vertical pulverizer system using the housing 100.

[0040] like Figure 5As further shown, the bottom plate 144 may also include a hole 150 formed substantially through the bottom plate 144. The hole 150 may be formed through the center of the bottom plate 144 and may substantially receive a portion of a rotatable table of a vertical mill system using the housing 100. The hole 150 of the bottom plate 144 may be substantially aligned with the bottom seal 152. That is, the bottom seal 152 may be coupled to the hole 150 of the bottom plate 144 and may line the hole of the bottom plate. As discussed herein, the bottom seal 152 may prevent gas (e.g., air) provided to the cylindrical body 102 via the air inlet opening 126 from leaking out of the cylindrical body 102 between the bottom plate 144 and the rotatable table of the vertical mill system. In another non-limiting example, the bottom seal 152 may prevent raw materials discharged and / or discarded from the rotatable table from falling from the housing 100 and / or entering different parts of the vertical mill system that may be damaged by the discharged and / or discarded raw materials.

[0041] As described above, the surface 148 of the bottom plate 144 is formed as a spherical disk (a portion of a sphere having a substantially constant radius), not a quasi-spherical shape, and does not contain any knuckles or transitions of different radius connecting the bottom plate 144 to the inner surface / sidewall 146 of the housing 100. In particular, the surface 148 of the bottom plate 144 has a substantially constant radius throughout the entire extent of the surface 148 (from the seal 152 to the inner surface 146 of the cylindrical body 102). Figure 8 As best shown in FIG. 1 , the intersections of the bottom plate 144 and the inner surface / sidewall 146 of the housing 100 include rounded corner areas (eg, first rounded corners 154 and second rounded corners 156 ) that serve to reduce stress concentrations at such intersections.

[0042] It has been found that the spherical disc bottom plate 144 has the pressure limiting benefits of a conventional quasi-spherical bottom plate, but has the advantage of a simplified, lower stress, connection to the mill side housing. The spherical disc bottom plate 144 is simpler to manufacture than a conventional quasi-spherical bottom plate because it is a constant radius throughout (without any knuckle radius).

[0043] As indicated above, both the spherical disc floor 144 and the elliptical inlet duct 128 reduce operating stresses in the grind side of the pulverizer and reduce grind side manufacturing costs (both labor and materials) compared to conventional quasi-spherical floors and rectangular inlet ducts, respectively. Fig. 9 and Fig.10Results of finite element analyses of the relative thermal stresses experienced by the inlet duct and ball pan floor / mill side housing connection of the present invention are shown, respectively. These analyses show no elevated stresses in critical areas where prior art designs would typically have seen elevated stress concentrations. As demonstrated by these finite element analyses, the inlet duct geometry and mill side floor geometry of the present invention meet established regulatory standards and minimize or eliminate the need for thicker material and reinforcements in areas that would typically experience high stress concentrations.

[0044] In an embodiment, the housing 100 disclosed herein can be part of a vertical mill system, such as disclosed in U.S. Patent Application Publication 2018 / 0036739, which is hereby incorporated by reference in its entirety.

[0045] In an embodiment, a housing of a pulverizer system is provided. The housing includes a generally cylindrical body forming an inner cavity having a central axis, a cover positioned above the cylindrical body, and a bottom plate positioned in the inner cavity of the cylindrical body and opposite to the cover, the bottom plate having a surface extending from a point closest to the central axis to the inner side wall of the cylindrical body. The surface of the bottom plate has a substantially constant radius of curvature. In an embodiment, the surface is configured as a spherical disk. In an embodiment, the surface does not contain a knuckle having a radius different from the constant radius of curvature of the surface. In an embodiment, the bottom plate also includes a hole formed through the bottom plate, the hole being configured to receive a rotatable table of a pulverizer system. In an embodiment, the housing may also include a bottom seal, the bottom seal being coupled to the hole of the bottom plate and lining the hole of the bottom plate, wherein the surface having the constant radius of curvature extends from the bottom seal to the inner side wall. In an embodiment, the shell includes a first fillet, the first fillet is located at the intersection of the bottom plate and the inner side wall of the cylindrical body, and the first fillet is generally located above the bottom plate. In an embodiment, the shell includes a second fillet, the second fillet is located at the intersection of the bottom plate and the inner side wall of the cylindrical body, and the second fillet is generally located below the bottom plate. In an embodiment, the shell includes an air inlet opening formed through the cylindrical body and an air inlet duct substantially surrounding the air inlet opening, and the air inlet opening is positioned above the bottom plate. In an embodiment, the air inlet duct has a curved end and does not contain sharp corners. In an embodiment, the cross-section of the air inlet duct is elliptical. In an embodiment, the cross-section of the air inlet duct is circular. In an embodiment, the shell also includes only a single layer of reinforcement around the boundary of the air inlet duct.

[0046] In another embodiment, a housing for a pulverizer system is provided. The housing includes a generally cylindrical body forming an inner cavity having a central axis; a cover positioned above the cylindrical body; a bottom plate positioned within the inner cavity of the cylindrical body and opposite the cover; an air inlet opening formed through the cylindrical body, the air inlet opening being positioned above the bottom plate; and an air inlet duct substantially surrounding the air inlet opening, the air inlet duct having a curved end and being free of sharp corners. In an embodiment, the cross-section of the air inlet duct is elliptical. In an embodiment, the cross-section of the air inlet duct is circular. In an embodiment, the housing includes only a single layer of reinforcement surrounding the boundary of the air inlet duct. In an embodiment, the bottom plate has a surface extending from a point closest to the central axis to the inner side wall of the cylindrical body, wherein the surface of the bottom plate has a substantially constant radius of curvature. In an embodiment, the bottom plate further comprises a hole formed through the bottom plate, the hole being configured to receive a rotatable table of a shredder system, wherein the housing further comprises a bottom seal coupled to and lining the hole of the bottom plate, and wherein the surface having the constant radius of curvature extends from the bottom seal to the inner sidewall. In an embodiment, the housing further comprises at least one of a first fillet and / or a second fillet, the first fillet being located at an intersection of the bottom plate and the inner sidewall of the cylindrical body, the first fillet being located substantially above the bottom plate, the second fillet being located at the intersection of the bottom plate and the inner sidewall of the cylindrical body, and the second fillet being located substantially below the bottom plate.

[0047] In yet another embodiment, a pulverizer system is provided. The pulverizer system includes a housing having: a generally cylindrical body forming an inner cavity having a central axis; a cover positioned above the cylindrical body; a bottom plate positioned within the inner cavity of the cylindrical body and opposite to the cover, the bottom plate having a surface extending from a point closest to the central axis to the inner side wall of the cylindrical body, the bottom plate having a substantially constant radius of curvature; an air inlet opening formed through the cylindrical body, the air inlet opening being positioned above the bottom plate; and an air inlet duct substantially surrounding the air inlet opening, the cross section of the air inlet duct being elliptical. In an embodiment, the housing includes at least one of a first fillet and / or a second fillet, the first fillet being located at an intersection of the bottom plate and the inner side wall of the cylindrical body, the first fillet being located substantially above the bottom plate, the second fillet being located at the intersection of the bottom plate and the inner side wall of the cylindrical body, and the second fillet being located substantially below the bottom plate.

[0048] As used herein, an element or step listed in the singular and beginning with the word "one" or "a kind of" should be understood as not excluding a plurality of said elements or steps, unless such exclusion is explicitly stated. In addition, reference to "one embodiment" of the present invention is not intended to be interpreted as excluding the existence of other embodiments that also include the listed features. In addition, unless explicitly stated to the contrary, an embodiment that "includes," "comprises," or "has" an element or multiple elements with a particular attribute may include other such elements that do not have that attribute.

[0049] This written description uses examples to disclose several embodiments of the invention, including the best mode, and also enables a person of ordinary skill in the art to practice the embodiments of the invention, including making and using any device or system and performing any combined methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to a person of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. A housing of a pulverizer system, the housing comprising: a generally cylindrical body defining an interior cavity having a central axis; a cover positioned over the cylindrical body; a bottom plate positioned within the inner cavity of the cylindrical body opposite the cover, the bottom plate having a surface extending from a point closest to the central axis to an inner side wall of the cylindrical body; an air inlet opening formed through the cylindrical body, the air inlet opening being positioned above the bottom plate; and an air intake duct surrounding the air intake opening, the air intake duct having two opposite curved sides and linear / flat top and bottom sides connecting tangent points of the two opposite curved sides, wherein the two opposite curved sides and the linear / flat top and bottom sides do not contain sharp corners, Wherein the surface of the base plate has a substantially constant radius of curvature.

2. The housing according to claim 1, wherein: The surface is configured as a spherical disk.

3. The housing according to claim 1, wherein: The surface is free of a knuckle having a radius different than the constant radius of the curvature of the surface.

4. The housing according to claim 1, wherein: The base plate also includes an aperture formed therethrough, the aperture being configured to receive a rotatable table of a shredder system.

5. The housing according to claim 4, further comprising: a bottom seal coupled to and lining the hole in the bottom plate; wherein the surface having the constant radius of curvature extends from the bottom seal to the inner sidewall.

6. The housing according to claim 5, further comprising: A first fillet is located at an intersection of the bottom plate and the inner sidewall of the cylindrical body, the first fillet being located substantially above the bottom plate.

7. The housing according to claim 5, further comprising: A second fillet is located at an intersection of the bottom plate and the inner sidewall of the cylindrical body, the second fillet being located substantially below the bottom plate.

8. The housing according to claim 1, wherein: The cross section of the air intake duct is oval.

9. The housing according to claim 1, further comprising: Only a single layer of reinforcement around the border of the air intake duct.

10. A housing of a pulverizer system, the housing comprising: a generally cylindrical body defining an interior cavity having a central axis; a cover positioned over the cylindrical body; a bottom plate positioned within the inner cavity of the cylindrical body opposite the cover; an air inlet opening formed through the cylindrical body, the air inlet opening being positioned above the bottom plate; and An air intake duct surrounds the air intake opening, the air intake duct having two opposite curved sides and linear / flat top and bottom sides connecting the tangent points of the two opposite curved sides, wherein the two opposite curved sides and the linear / flat top and bottom sides do not contain sharp corners.

11. The housing according to claim 10, wherein: The cross section of the air intake duct is oval.

12. The housing according to claim 10, further comprising: Only a single layer of reinforcement around the border of the air intake duct.

13. The housing according to claim 10, wherein: The base plate has a surface extending from a point closest to the central axis to the inner side wall of the cylindrical body; Wherein the surface of the base plate has a substantially constant radius of curvature.

14. The housing according to claim 13, wherein: The base plate further includes an aperture formed therethrough, the aperture configured to receive a rotatable table of a shredder system; wherein the housing further comprises a bottom seal coupled to and lining the hole of the bottom plate; and wherein the surface having the constant radius of curvature extends from the bottom seal to the inner sidewall.

15. The housing according to claim 10, further comprising: At least one of a first fillet and / or a second fillet, the first fillet is located at the intersection of the base plate and the inner side wall of the cylindrical body, the first fillet is substantially located above the base plate, the second fillet is located at the intersection of the base plate and the inner side wall of the cylindrical body, and the second fillet is substantially located below the base plate.

16. A pulverizer system, comprising: A housing, the housing comprising: a generally cylindrical body defining an interior cavity having a central axis; a cover positioned over the cylindrical body; a bottom plate positioned within the inner cavity of the cylindrical body opposite the cover, the bottom plate having a surface extending from a point closest to the central axis to an inner sidewall of the cylindrical body, the bottom plate having a substantially constant radius of curvature; an air inlet opening formed through the cylindrical body, the air inlet opening being positioned above the bottom plate; and An air intake duct surrounds the air intake opening, the air intake duct having two opposite curved sides and linear / flat top and bottom sides connecting the tangent points of the two opposite curved sides, wherein the two opposite curved sides and the linear / flat top and bottom sides do not contain sharp corners.

17. The pulverizer system of claim 16, wherein: The shell includes at least one of a first rounded corner and / or a second rounded corner, the first rounded corner is located at the intersection of the bottom plate and the inner wall of the cylindrical body, the first rounded corner is substantially above the bottom plate, the second rounded corner is located at the intersection of the bottom plate and the inner wall of the cylindrical body, and the second rounded corner is substantially below the bottom plate.

Images