[0001] This disclosure relates in general to pump casing arrangements for centrifugal pumps, particularly those where the pump is submersible in fluid environments, and relates to arrangements for attachment of a strainer device in use within the fluid environment.

Background of Related Art:

[0002] Submersible pumps are used in many industries and environments to remove fluid from a sump or recessed body of fluid. Such industries may include agriculture, oil and gas drilling, slurry pumping, minerals processing, dredging and general drainage, among others. In many industrial uses, the pump is used to process slurries, containing water and abrasive particulate matter suspended in the water.

[0003] Submersible pumps vary widely in design and configuration, but generally include a motor housing attached to a pump casing which houses an impeller within a pumping chamber. The casing has (i) an inlet, positioned towards the bottom of the sump or body of fluid, and (ii) an outlet for directing fluid away from the pump casing and away from the body of fluid. Such submersible pump designs may also include a base attached to the pump arrangement that allows the submersible pump to be positioned on the floor of the body of fluid, and may also include a strainer device located near the base for preventing larger solid materials from entering into the pump inlet from the body of fluid.

[0004] Certain conventional submersible pump configurations are comprised of multiple pump elements or structures that are stacked and secured to each other in an end-to-end arrangement. Such submersible pumps are not only expensive to manufacture due to exacting casting and finishing requirements, but are difficult to assemble. They are also subject to pressure conditions in use that lead to failure of the numerous bolts that are required to join and secure the multiple separate elements together. [0005] The disclosures provided herein are directed to addressing the described problems, as well as others, which are encountered with respect to manufacture, assembly and use of conventional centrifugal pumps, especially those that are submersible, and including centrifugal pumps that are not used in submersible processing environments.

Brief Summary

[0006] In a first aspect, a centrifugal pump arrangement is disclosed comprised of a pump casing having an outer circumferential periphery, an annular radial surface, a volute, an outlet in fluid communication with the volute and an inlet positioned opposite the annular radial surface, the inlet having an annular inlet flange; an impeller positioned within the volute of the pump casing; a wear plate located adjacent the impeller; and a backing plate positioned adjacent to the annular radial surface of the pump casing, the wear plate being positioned between the impeller and the backing plate. This aspect of the disclosure provides an arrangement of elements that is unique in orientation and number of parts which facilitates manufacture and assembly, while providing greater resistance to failure of the securement devices during operation.

[0007] In certain embodiments, the annular radial surface of the pump casing extends radially inwardly from the circumferential periphery toward a central axis of the pump casing and is formed with an opening for receiving and retaining the wear plate. [0008] In certain other embodiments, the annular inlet flange extends substantially radially outwardly from the inlet and away from a central axis of the pump casing.

[0009] In yet other embodiments, the annular inlet flange is formed with a plurality of recesses extending inwardly toward the central axis from an outer peripheral edge of the annular inlet flange.

[0010] In some embodiments, the backing plate is configured with a radially- extending annular body and an annular skirt portion that is sized and positioned to encircle the outer circumferential periphery of the pump casing.

[0011] In other embodiments, the annular body of the backing plate has an inner surface and an outer surface, the inner surface being positioned adjacent to the annular radial surface of the pump casing and the outer surface being oriented in a direction away from the inlet of the pump casing, the annular body further having a plurality of apertures for receiving securement devices to attach the backing plate to the pump casing.

[0012] In certain embodiments, the wear plate is secured against axially movement and rotation relative to the backing plate and to the impeller.

[0013] In some embodiments, a base is secured to the backing plate and positioned to intercalate the impeller between the base and the backing plate.

[0014] In other embodiments, the base is fitted with a sparger device.

[0015] In yet other embodiments, a strainer device is secured to the annular inlet flange of the pump casing.

[0016] In certain embodiments, the strainer device comprises a plurality of brackets configured to engage with the annular inlet flange.

[0017] In some embodiments, each bracket is formed with an adjustable securement element to secure the strainer device to the inlet flange.

[0018] In other embodiments, the strainer device is configured as a basket having a top portion, a bottom portion and an annular side portion extending between the top portion and the bottom portion, the basket having openings formed through the surfaces of the top portion, bottom portion and annular side portion.

[0019] In certain embodiments, a drive housing is positioned in proximity to the outer surface of the backing plate annular body and attached thereto, the drive housing having a drive shaft extended therefrom for attachment to the impeller for rotation of the impeller within the volute.

[0020] In yet other embodiments, a slinger apparatus is positioned adjacent to the wear plate and is connected to the drive shaft for rotation therewith.

[0021] In some embodiments, the slinger apparatus is located between wear plate and the drive housing.

[0022] In other embodiments, an agitator device is attached to the drive shaft and is positioned to extend through the inlet of the pump casing and through a strainer device attached to the inlet flange. [0023] In a second aspect, a strainer device is disclosed for use with a centrifugal pump, the strainer device comprising a top portion, a bottom portion and an annular side portion extending between the top portion and the bottom portion, the top portion having a central opening oriented for positioning against a pump casing in use; one or more brackets positioned about the central opening formed in the top portion; and securement elements formed with each of said brackets positioned to secure the brackets to a pump casing element in use. The strainer device provides an advantage over known strainer devices used with centrifugal pumps in that it is attached to the inlet of the pump casing in a manner that allows easier assembly or attachment, and is selfaligning and self-centering.

[0024] The strainer device may define a plurality of apertures of different sizes and disposed in rows.

[0025] In a third aspect, a method of assembling a centrifugal pump arrangement is disclosed, comprising providing a pump casing having a volute, an outlet in fluid communication with the volute and an inlet having an annular inlet flange; providing a backing plate sized in circumference to receive the pump casing thereagainst; providing an impeller; providing a drive mechanism housing; providing a strainer device; orienting the pump casing to position the volute in an upward orientation opposite the inlet; positioning the impeller within the volute of the pump casing; positioning the backing plate against the pump casing to position the impeller between the backing plate and the pump casing and securing the backing plate to the pump casing; attaching the drive mechanism housing to the backing plate; and securing the strainer device to the inlet flange of the pump casing.

[0026] In certain embodiments, the method further comprises providing a wear plate and positioning the wear plate adjacent to the impeller before positioning the backing plate against the pump casing so that the wear plate is positioned between the impeller and the backing plate.

[0027] In other embodiments, the method further comprises providing a base for supporting the pump casing and securing the base to the pump casing and backing plate following positioning of the impeller within the volute of the pump casing either before or after the strainer device is secured to the inlet flange.

[0028] In yet other embodiments, the method further comprises positioning a slinger apparatus adjacent to the wear plate before securing the backing plate to the pump casing to position the slinger apparatus between the wear plate and the drive mechanism housing in use.

[0029] In some embodiments, the strainer device is attached to the inlet flange by one or more brackets positioned between the strainer device and the inlet flange.

[0030] These aspects and others are more fully described in detail below, with particular reference to the drawings.

Brief Description of the Several Views of the Drawings

[0031] FIG. 1 is an exploded view of a conventional submersible centrifugal pump of the prior art;

[0032] FIG. 2 is a perspective view in partial cutaway of a centrifugal pump arrangement in accordance with an embodiment of the present invention;

[0033] FIG. 3 is an exploded view of the arrangement shown in FIG. 2;

[0034] FIG. 4 is an enlarged view in radial cross section of a portion of the centrifugal pump arrangement;

[0035] FIG. 5 is an exploded view in cross section of certain of the elements shown in FIG. 4;

[0036] FIG. 6 is a perspective view of the inlet side of the pump casing;

[0037] FIG. 7 is a perspective view from the top of a strainer device in accordance with another embodiment of the present invention;

[0038] FIG. 8 is a cross section view in elevation of a strainer device connected to the pump casing; and

[0039] FIG. 9 is a perspective top view of the strainer device depicting the attachment to the inlet flange of a pump casing;

[0040] FIG. 10 is a perspective view from the top of a strainer device in accordance with yet another embodiment of the present invention; [0041] FIG. 11 is a cross section view in elevation of the strainer device of Fig. 10 connected to the pump casing; and

[0042] FIG. 12 is a perspective top view of the strainer device of Fig. 10 depicting the attachment to the inlet flange of a pump casing.

Detailed Description

[0043] FIG. 1 depicts an example of a submersible centrifugal pump of conventional design and is shown for comparative purposes. The conventional submersible centrifugal pump 10 typically includes a motor housing 12 which contains the drive mechanism, comprising a drive shaft 14, which extends through a bearing assembly 16 and into a pump casing 18 for attachment to an impeller 20. The impeller 20 is, in use, positioned within a pumping chamber or volute (not viewable) accessible through an open end 22 of the pump casing 18 that, in use, is oriented toward the bottom of a body of fluid. The pump casing 18 is structured with an outlet passage 24 which extends from the volute for discharge of fluid and includes a radially-oriented flange 26. The open end 22 of the pump casing 18 is effectively closed by attachment to a suction end casing 28, sometimes configured in the form of a throatbush, which encloses the impeller 20 within the pumping chamber of the pump casing 18. A strainer device 30 is connected to the suction end casing 28 about its periphery and is supported by a base 32, to which it is attached. An agitator device 34 may be attached to the end of the drive shaft 14 and is located within the base 32 to stir particulate matter at the bottom of a body of fluid.

[0044] The conventional submersible centrifugal pump 10 shown in FIG. 1 is a combination of stacked elements that are in an end-to-end configuration. Conventional submersible centrifugal pumps are comprised of a multiplicity of parts that require exact casting and finishing methods to assure proper alignment of the parts for joining. Additionally, the multiple number of parts requires a multiplicity of bolting arrangements that are subjected to various pressure conditions that lead to degradation and failure of the bolts. Further, conventional arrangements of the type illustrated in FIG. 1 require a complex assembly that involves inverting certain of the parts to fit and align them in an exacting manner, which makes assembly difficult and time consuming. The task of repairing or replacing worn parts is difficult and costly as well.

[0045] A submersible centrifugal pump arrangement in accordance with one embodiment of the present invention is shown in FIGS. 2 and 3, and is directed to overcoming some of the problems experienced with conventional submersible centrifugal pumps. The submersible centrifugal pump arrangement 100 illustrated in FIGS. 2 and 3 generally comprises a pump casing 102 having an outer circumferential periphery 104, an annular radial surface 106, a volute 110, and an outlet 112 in fluid communication with the volute 110. The pump casing 102 has an inlet 116 oriented and positioned opposite the annular radial surface 106. The inlet 116 has an annular inlet flange 120 (FIG. 4).

[0046] An impeller 122 is positioned within the volute 110 of the pump casing 102. A wear plate 126 may be located adjacent the impeller 122 in the assembly. A backing plate 130 is positioned adjacent to the annular radial surface 106 of the pump casing 102 so that the wear plate 126 is positioned between the impeller 122 and the backing plate 130 in use.

[0047] The centrifugal pump arrangement 100 of the disclosure further includes a waterproof drive housing 134 which houses a motor (not shown) that powers the rotation of a drive shaft 136 that is attached to the impeller 122 for rotation of the impeller 122.

[0048] As illustrated more fully in FIGS. 4 and 5, the pump casing 102 has an open end 140 which leads into the pumping chamber 138 or volute 110. The open end 140 is oriented in use in a generally upward direction. In this context, “generally upward” means that when submersed in a body of fluid, the centrifugal pump arrangement 100 is typically in a vertical orientation, but may be positioned at other than a strictly vertical orientation as needed for a particular pumping operation. Consequently, the open end 140 of the pump casing 102 is oriented generally upwardly away from the bottom of a body of fluid (such as a lake or pond) in which the centrifugal pump arrangement 100 is placed and is oriented away from the inlet 116. This orientation of the pump casing 102 is atypical to conventional arrangements. [0049] The pump casing 102 has a circumferential periphery 104 surrounding an upper flange 142 of the pump casing 102. An annular radial surface 106 extends radially inwardly from the circumferential periphery 104 to the open end 140 of the pump casing 102 to provide a receiving surface for the backing plate 130. A plurality of bores 144, which may be in the form of recessed notches, are formed in or through the upper flange 142 as described more fully below.

[0050] The open end 140 is formed with a recess 148 having a shoulder 150 which is sized to receive and retain the wear plate 126. The open end 140 leads into the pumping chamber 138 or volute 110. The open end 140 is positioned opposite to the inlet 116 of the pump casing 102. As best seen in FIG. 4, the volute 110 has a discharge opening 152 through which fluid exits the volute 110 through the outlet 112. [0051] The pump casing 102 is further formed with an annular inlet flange 120 that encircles the inlet 116 and extends radially away from the inlet 116 in a direction away from the central axis 154 of the pump casing 102. The annular inlet flange 120 may extend perpendicularly to the central axis 154 or may be canted at an angle other than perpendicular to the central axis 154. As best seen in FIG. 6, the annular inlet flange 120 may be formed with one or more recesses 156 that extend inwardly from an outer peripheral edge 158 of the annular inlet flange 120. The purpose of the one or more recesses 156 is described more fully hereinafter.

[0052] As best seen in FIG. 4, the impeller 122 is positioned within the pumping chamber 138 or volute 110, and is secured to the drive shaft 136 through the hub 162 of the impeller 122. It can further be seen that the wear plate 126 has a central opening 164 through which the drive shaft 136 extends, and through which the hub 162 of the impeller 122 may be received. Notably, the wear plate 126 is not attached to the drive shaft 136 and is stationary relative to the impeller 122.

[0053] The backing plate 130 of the centrifugal pump arrangement 100 is configured with a radially-extending annular body 168 and an annular skirt portion 170 that extends generally axially from the annular body 168. The annular skirt portion 170 is sized and positioned to encircle the circumferential periphery 104 of the pump casing 102. The annular body 168 of the backing plate 130 has an outer surface 172 and an opposing inner surface 174 that is positioned adjacent to the annular radial surface 106 of the pump casing 102 when assembled. The outer surface 172 is oriented in a direction away from the inlet 116 of the pump casing 102 while the inner surface 174 of the backing plate 130 is oriented in a direction toward the inlet 116 of the pump casing 102. [0054] The annular body 168 has a central opening 176 through which the drive shaft 136 extends. The central opening 176 may be configured with a shoulder 178 into which an end of the drive housing 134 may be positioned. A plurality of apertures 180 are formed in the outer surface 172 of the annular body 168 about the central opening 176 to accommodate bolts 182 which secure the drive housing 134 to the outer surface 172 of backing plate 130. The annular body 168 is also configured with a plurality of apertures 186 or bores formed through and about a peripheral portion 188 of the annular body 168 for receiving securement devices such as bolts 190 (FIGS. 2 and 3) to facilitate securement of the backing plate 130 to the pump casing 102, the apertures 186 of the backing plate 130 being aligned with the bores or notches 144 formed in the pump casing 102.

[0055] The inner surface 174 of the backing plate 130 may be configured with a recess 194 into which an upper portion 196 of the wear plate 126 is received. The backing plate 130 may be configured with one or more holes 198 formed through the annular body 168 through which connector bolts 200 may be positioned. The connector bolts 200 secure the wear plate 126 to the pump casing to prevent axial movement of the wear plate 126 and to prevent rotation of the wear plate 126 relative to the backing plate 168.

[0056] A space 204 may be provided in the central opening 176 of the annular body 168 of the backing plate 130 which may be sized to accommodate a slinger apparatus 206, as seen in FIG. 2, which is attached to the drive shaft 136. The slinger apparatus 206, in assembly, is positioned between the wear plate 126 and the drive housing 134. As best seen in FIG. 5, where the slinger apparatus is not shown for ease of understanding, one or more relief openings 208 may be formed about the backing plate 130 along the skirt portion 170 to allow fluid expelled from the back of the impeller 122 to exit radially out from backing plate 130. [0057] In a further aspect of the disclosure, a strainer device 212 as shown in FIGS. 7-9 is provided for use with a centrifugal pump arrangement 100 of the disclosure for preventing certain sized debris from entering into the inlet 116 of the pump casing 102. In accordance with this aspect, the strainer device 212 has a top portion 214, a bottom portion 216 and an annular side portion 218 extending between the top portion 214 and the bottom portion 216. The top portion 214, bottom portion 216 and annular side portion 218 are formed with a plurality of openings 210 therethrough which allow fluid to enter the strainer device 212, but which prevent entry of solid material of a select size. The openings 210 may be of the same diameter or of various diameters. The top portion 214 protrudes radially beyond the bottom portion 216, and the annular side portion 218 slopes radially inwards from the top portion 214 to the bottom portion 216. [0058] In this embodiment, the annular side portion 218 comprises a plurality of types (or sizes) of aperture. A largest size aperture is disposed in three vertically offset rows extending from near the top portion 214 towards the bottom portion 216. A smaller aperture size is disposed as a lower row, vertically offset and aligned with the largest aperture size rows, and located closer to the bottom portion 216. Smallest apertures are disposed as an upper and lower row, horizontally and vertically offset from the largest size apertures. Apertures slightly larger than the smallest apertures are disposed in three rows, each column of which is aligned with the smallest apertures. [0059] The top portion 214 has a central opening 220 oriented for positioning adjacent to or against the pump casing 102, namely in the region of the inlet 116. To that end, the strainer device 212 may be structured with apparatus for attaching the strainer device 212 to the annular inlet flange 120 of the pump casing 102. By way of example, the strainer device 212 may have one or more brackets 222 positioned about the central opening 220 of the strainer device 212 and formed in, or secured to, the top portion 214 of the strainer device 212. The one or more brackets 222 may be configured as angle brackets which each provide an arm 224 extended in a direction toward the central axis 154 of the centrifugal pump 100 and positioned to register with the annular inlet flange 120 of the pump casing 102. [0060] As best seen in FIG. 9, when installing the strainer device 212 in registration with the annular inlet flange 120, the strainer device 212 is initially positioned below the annular inlet flange 120 with each arm 224 of a respective bracket 222 positioned in alignment with one of the recesses 156 formed in the annular inlet flange 120. The strainer device 212 is then raised or brought closer to the annular inlet flange 120 until the arms 224 of each bracket 222 have cleared the upper surface 160 of the annular inlet flange 120. The strainer device 212 can then be rotated relative to the annular inlet flange, positioning the arm 224 of each bracket 222 in registration with the upper surface 160 of the annular inlet flange 120. Each of the brackets 222 may be provided with a securement element 226, such as a set screw, that, when tightened, secures the strainer device 212 to the annular inlet flange 120.

[0061] An alternative design of a strainer device 212’ is shown in FIGS. 10-12, and is provided for use with a centrifugal pump arrangement 100 of the disclosure for preventing certain sized debris from entering into the inlet 116 of the pump casing 102. [0062] The strainer device 212’ is similar to the strainer device 212 except that the top portion 214’ and the bottom portion 216’ have the same diameter so that the annular side portion 218’ extending between the top portion 214’ and the bottom portion 216’ is vertical rather than sloping. Thus, the strainer device 212’ has a cylindrical shape. Furthermore, the top portion 214’ is solid and does not include any openings 210 therethrough, except the central opening 220. The brackets 222 and arms 224 are identical on the two different strainer devices 212, 212’.

[0063] Having a solid top portion 214’ reduces the amount of debris that would otherwise be sucked into the inside of the strainer device 212’ through apertures in the top portion 214.

[0064] It may further be noted from FIG. 9 that the opening in the annular inlet flange 120, defined by a diameter of the inlet 116 of the pump casing 102, is sized to receive an agitator apparatus, or agitator rod 230, therethrough. The bottom portion 216 of the strainer device 212 is similarly formed with a central opening (not shown) through which the agitator rod 230 can pass. The agitator rod 230, as depicted in FIGS. 2 and 3, is attached to the end of the drive shaft 136 and is fixed with an agitator device 232 at its terminal end.

[0065] The configuration of the components of the centrifugal pump arrangement 100 greatly facilitates assembly of the centrifugal pump since the arrangement can be assembled in an upright orientation consistent with the orientation in which the pump will be placed for operation, contrary to conventional submersible pump arrangements that require inverting several component parts for assembly. This is particularly the case with conventional strainer devices that are attached to the outer periphery of the pump casing, which requires inversion of the parts for assembly, and which complicates proper alignment of the parts. With the centrifugal pump arrangement 100 of the present disclosure, the strainer device 212 is self-centering and self-aligning and can be assembled with the pump casing 102 and other parts in an upright orientation.

[0066] The centrifugal pump arrangement 100 of the disclosure may further include a base 236 which supports the pump casing 102 and backing plate 130. As depicted in FIGS. 2 and 3, the bolts 190 that are positionable through the bores of notches 144 in the pump casing 102 and the apertures 186 of the backing plate 130 can also be passed through similarly aligned passages 238 in a flange 240 of the base 236 to secure the base 236, pump casing 102 and backing plate 130 together with one set of bolts 190. This feature enables a reduction in parts and concomitantly the potential for bolt failure. Alternatively, a plurality of studs 241 may also be used to hold the backing plate 130 to the base 236, the studs 241 being positioned to pass through the bores or notches 144 of the pump casing 130.

[0067] The base 236 may also be fitted with a sparger device 242 (best seen in FIG. 2) that is trained in the direction of the strainer device 212 to clear trapped debris from the openings 210 in the strainer device 212.

[0068] In a further aspect of the disclosure, a method for assembling a centrifugal pump arrangement 100 comprises providing a pump casing 102 having a volute 110, an outlet 112 in fluid communication with the volute 110 and an inlet 116 having an annular inlet flange 120, and further providing a backing plate 130 sized in circumference to receive the pump casing 102 therewithin; providing an impeller 122; providing a drive mechanism housing 134; providing a strainer device 212, and then orienting the pump casing 102 to position the volute 110 in an upward direction. The impeller 122 is positioned within the volute 110 of the pump casing 102 followed by positioning the backing plate 130 against the pump casing 102 to position the impeller 122 between the backing plate 130 and the pump casing 102 and securing the backing plate 130 to the pump casing 102. The drive mechanism housing 134 is then attached to the backing plate 130. The strainer device 212 is also attached to the inlet flange 120 of the pump casing 102.

[0069] A further element of the method of assembly comprises providing a wear plate 126 and positioning the wear plate 126 adjacent to the impeller 122 before positioning the backing plate 130 against the pump casing 102 so that the wear plate 126 is positioned between the impeller 122 and the backing plate 130. In a further element of the method, a base 236 for supporting the pump casing 102 is provided and the base 236 is secured to the pump casing 102 and backing plate 130 following positioning of the impeller 122 within the volute 110 of the pump casing 102, either before or after the strainer device 236 is secured to the annular inlet flange 120.

[0070] A further element of the method includes positioning a slinger apparatus 206 adjacent to the wear plate 126 before securing the backing plate 130 to the pump casing 102 to position the slinger apparatus 206 between the wear plate 126 and the drive mechanism housing 134. Another element of the method includes attaching the strainer device 212 to the annular inlet flange 120 by one or more brackets 222 positioned between the strainer device 212 and the annular inlet flange 120.

[0071] In the foregoing description of certain embodiments, specific terminology has been resorted to for the sake of clarity. However, the disclosure is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes other technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as "upper" and "lower", "above" and "below" and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms. [0072] In this specification, the word “comprising” is to be understood in its “open” sense; that is, in the sense of “including”, and thus not limited to its “closed” sense, that is, the sense of “consisting only of”. A corresponding meaning is to be attributed to the corresponding words “comprise", "comprised" and "comprises" where they appear.

[0073] The preceding description is provided in relation to several embodiments which may share common characteristics and features. It is to be understood that one or more features of any one embodiment may be combinable with one or more features of the other embodiments. In addition, any single feature or combination of features in any of the embodiments may constitute additional embodiments. In addition, the foregoing describes only some embodiments of the disclosed structures, and alterations, modifications, additions and/or changes can be made thereto without departing from the scope of the present invention, the embodiments being illustrative and not restrictive.

Reference Numerals

Centrifugal pump arrangement 100

Pump casing 102

Outer circumferential periphery 104

Annular radial surface 106

Volute 110

Outlet 112

Inlet 116

Annular inlet flange 120

Impeller 122

Wear plate 126

Backing plate 130

Drive housing 134

Drive shaft 136

Pumping chamber 138

Open end 140

Upper flange 142 Bores 144

Recess 148

Shoulder 150

Discharge opening 152

Central axis 154

Recesses 156

Outer peripheral edge 158

Hub (of impeller) 162

Central opening 164

Annular body 168

Annular skirt portion 170

Outer surface 172

Inner surface 174

Central opening 176

Shoulder 178

Apertures 180

Bolts 182

Apertures (of annular body) 186

Peripheral portion 188

Bolts 190

Recess 194

Upper portion 196

Holes 198

Connector bolts 200

Space 204

Slinger apparatus 206

Relief openings 208

Openings 210

Strainer device 212, 212’

Top portion 214, 214’ Bottom portion 216, 216’

Annular side portion 218, 218’

Central opening 220, 220’

Brackets 222

Arm (of brackets) 224

Securement element (of brackets) 226

Agitator apparatus 230

Agitator device 232

Base 236

Passages 238

Studs 241

Sparger device 242