FIELD OF THE INVENTION

[0001] The invention relates to a sealing system for a pump shaft.

BACKGROUND TO THE INVENTION

[0002] The following discussion of the background to the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was published, known or part of the common general knowledge in any jurisdiction as at the priority date of the application.

[0003] Pumps are used to impart kinetic energy into a fluid to increase its pressure, flow rate, or both. This is generally achieved by way of an impeller or other component attached to a pump shaft. This means that the pump shaft needs to be sealed to prevent leakage into the pump itself.

[0004] Traditionally, sealing of pumps, and other kinds of rotating machinery, has been achieved by packing material (originally in the form of oiled leather and hemp but now more commonly in the form of greased rope). This packing material is compressed (or “packed”) about the shaft in the area immediately surrounding the pump shaft. The problem with this arrangement is that the packing material is subject to friction which generates heat which can compromise the packing material.

[0005] To cool and lubricate the gland packing, fluid (typically water) is periodically flushed into the space between the packing and the shaft seal. This flushing fluid is not insubstantial, commonly amounting to thirty litres per minute (30l/min) per pump. With mineral processing plants making use of multiple pumps, pumps represent a significant amount of total water usage by such processing plants.

[0006] Additionally, in the case of mineral processing plants, access to clean water may not be readily available. More likely, the water the processing plant has access to will be salty, acidic, caustic, or may include process contaminants (hereafter referred to more generally as “compromised flush water”). [0007] This compromised flush water damages the gland packing and shaft sleeve which eventually culminates in the pump leaking and providing the compromised flush water with access to the bearing housing. When the compromised flush water enters the bearing housing, this results in regular pump failures. In the best-case scenario, this represents additional maintenance costs to the processing plant operator. In the worst-case scenario, this may require shutdown of the processing plant resulting in additional maintenance costs and lost production capacity.

[0008] It should also be noted that the use of compromised flush water may require the processing plant operator to conduct further processing steps in order to deal with the contaminant, excess acidity, causticity, etc and thereby allow it to be used as flush water for a pump. Thus, the use of compromised flush water presents additional technical, environmental and safety problems for the processing plant operator.

[0009] It is therefore an object of the present invention to provide a sealing system for a pump shaft that alleviates, or at least ameliorates in part, one or more of the aforementioned problems.

SUMMARY OF THE INVENTION

[0010] Throughout this document, unless otherwise indicated to the contrary, the terms “comprising”, “consisting of”, and the like, are to be construed as non- exhaustive, or in other words, as meaning “including, but not limited to”.

[0011] In accordance with a first aspect of the invention there is a sealing system for a pump shaft, the pump shaft having an impeller attached thereto and forming part of a pump, comprising: a shaft sleeve having a bore for receiving the pump shaft, the shaft sleeve having been polished to a low friction finish; a sealing cartridge having a sealing recess and a bore for receiving the shaft sleeve, the sealing recess surrounding the bore; a lubricant delivery system to deliver lubricant to a location within the sealing recess; and where the sealing recess has a plurality of lip seals, a first set of lip seals positioned in series to an impeller side of the location and a sealing means positioned away from an impeller side of the location, where, during operation, the delivered lubricant is directed towards the first set of lip seals, each lip seal in the first set of lip seals being directed away from the shaft sleeve by the delivered lubricant to allow the delivered lubricant to reach the next lip seal in the series and thereby form a meniscus between each lip seal and the shaft sleeve.

[0012] In one configuration, the shaft sleeve has been polished to a mirror finish.

[0013] The sealing cartridge may include a removable end cap, the end cap operable to seal off the sealing recess when not removed from the sealing cartridge.

[0014] In a further configuration, the sealing cartridge has an enlarged section, the enlarged section operable to be received within a cover plate of a main body that at least partially encapsulates the sealing cartridge. In a further variation of this configuration, the pump has a bearing housing and where the main body further includes an attachment plate, the main body able to be secured to the bearing housing by way of the attachment plate and, when so secured, the enlarged section is able to move relative to the cover plate. A sealing means for sealing the enlarged section relative to the cover plate against fluid pumped by the pump may also be included.

[0015] The sealing system may also include a fluid recovery system, the fluid recovery system operable to retrieve lubricant from the location. The fluid recovery system may be a thermosiphon.

[0016] The lubricant delivery system may deliver lubricant in the form of sewing machine oil. In an alternative configuration, the lubricant delivery system delivers lubricant in the form of grease. Regardless of the lubricant used, preferably, the lubricant delivery system is pressurised to deliver lubricant at a pressure equal to, or less than, the pressure of fluid pumped by a pump incorporating the pump shaft.

[0017] The lubricant delivery system may include a grease reservoir, the grease reservoir operable to delivery grease to a grease trap, and the first set of lip seals are located between the location and the grease trap. The grease may be imbued with polytetrafluoroethylene. [0018] The at least one sealing means positioned away from the impeller side of the location may take the form of a second set of lip seals. In this configuration, it is preferable that the lip seal of the second set of lip seals closest to the location deflects towards the impeller and the lip seal furthest from the location deflects away from the impeller.

[0019] In another variation, the second set of lip seals comprises a double lip seal comprising a base block having a recess in a side furthest from the shaft sleeve, and where each lip seal extends from a side of the base block closest to the shaft sleeve and where sealing means for sealing the base block relative to the sealing cartridge is located within the recess.

[0020] The end cap may have a pinhole provided therein and the base block is porous, such that a pin inserted through the pinhole into the base block maintains the position of the base block relative to the end cap.

[0021] Each lip seal ideally comprises a positioner and a sealing element and where the positioner comprises a first flange having an “L”-shaped cross-section and a smaller second flange also having an “L”-shaped cross-section, and where the flanges are connected at one end and co-aligned, the sealing element being located in a gap formed between the unconnected ends of the flanges. Each single lip seal may have a backing seal. Alternatively, or in addition, the sealing element may be made from a low-friction, low-elasticity material. The low-friction, low-elasticity material may be polytetrafluoroethylene or a combination of polytetrafluoroethylene, glass and molybdenum disulfide.

[0022] A spacer ring may be interposed between adjacent single lip seals.

[0023] In accordance with a second aspect of the present invention there is a contaminant containment system for a pump shaft comprising: a sealing cartridge having a sealing recess, an impeller face and a bore for receiving the pump shaft; where, the impeller face has a surface contour that directs pumped fluid seeking to enter the pump towards a flow path leading to a grease trap located in the sealing recess and where the flow path, when viewed in cross-section, doubles back on itself at least once. [0024] The flow path, when viewed in cross-section, preferably takes the form of a square wave form, the flow path being oriented substantially perpendicular to the pump shaft.

[0025] The sealing recess may further incorporate a restrictor bush, at least part of the restrictor bush acting as a containment wall. In a further configuration, the portion of the restrictor bush acting as a containment wall for the grease trap is resilient so as to allow pumped fluid that reaches the restrictor bush to enter the grease trap.

[0026] The contaminant containment system may also include a grease delivery system, the grease delivery system operable to deliver grease to the grease trap.

[0027] The contaminant containment system may also include a rotational connector adapted to receive a rotational force from the pump shaft, the rotational connector having a frontal side having a plurality of blades. In an alternative, or additional configuration, the rotational connector has an underside having a plurality of veins provided therein.

[0028] The rotational connector may have an abutting face and, when in operation, the abutting face is in direct contact with an impeller attached to the pump shaft.

[0029] In accordance with a third aspect of the present invention there is a pump shaft sealing system comprising: the sealing system for a pump shaft according to the first aspect of the invention; and the contaminant containment system for a pump shaft according to the second aspect of the invention, where, the common sealing recess has the first set of lip seals to the side of the location towards an impeller end that leads to the grease trap of the contaminant containment system.

[0030] In accordance with a fourth aspect of the present invention there is a method of sealing a pump shaft during operation, the pump shaft having an impeller attached thereto and forming part of a pump, the method comprising the steps of: inserting a pump shaft in a bore of a shaft sleeve, the shaft sleeve polished to a low friction finish; installing the shaft sleeve in a bore of a sealing cartridge, the shaft sleeve having a sealing recess and the installation being such that the sealing recess surrounds the shaft sleeve; installing a first set of lip seals positioned in series to an impeller side of a location; installing a second set of lip seals position away from an impeller side of the location; delivering lubricant to the location with the sealing recess; where, the delivered lubricant is directed towards the first set of lip seals, each lip seal in the first set of lip seals being directed away from the shaft sleeve by the delivered lubricant to allow the delivered lubricant to reach the next lip seal in the series and thereby form a meniscus between each lip seal and the shaft sleeve.

[0031] In accordance with a fifth aspect of the present invention there is a method of containing contaminants for a pump shaft, the method comprising the steps of: inserting a pump shaft in a bore of a shaft sleeve; installing the shaft sleeve in a bore of a sealing cartridge, the shaft sleeve having a sealing recess and the installation being such that the sealing recess surrounds the shaft sleeve; directing fluid seeking to enter the pump towards a flow path that, when viewed in cross section, doubles back on itself at least once, the fluid being directed by way of the surface contour of an impeller face forming part of the sealing cartridge; directing fluid that traverses the flow path to a grease trap located in the sealing recess. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is an isometric view of a sealing system for a pump shaft seal according to a first embodiment of the present invention.

Figure 2 is a cross-sectional view of the sealing system as shown in Figure 1 as incorporated into a pump.

Figure 3a is a first partial exploded view of part of the cross-sectional view of the sealing system as shown in Figure 2. Figure 3b is a second partial exploded view of part of the cross-sectional view of the sealing system as shown in Figure 2.

Figure 4 is a schematic view of a single lip seal as used in the sealing system shown in Figure 1.

Figure 5 is a schematic view of a double lip seal as used in the sealing system shown in Figure 2.

Figure 6 is a front isometric view of a sealing system for a pump shaft seal according to a second embodiment of the present invention.

Figure 7 is a rear isometric view of the sealing system shown in Figure 6.

Figure 8a is a first partial exploded view of part of the cross-sectional view of the sealing system as shown in Figure 6. Figure 8b is a second partial exploded view of part of the cross-sectional view of the sealing system as shown in Figure 6.

Figure 9a is a first view of a rotational connector as used in the sealing system as shown in Figure 6. Figure 9b is a second view of this same rotational connector.

PREFERRED EMBODIMENTS OF THE INVENTION

[0033] In accordance with a first embodiment of the invention there is a sealing system 10 for a pump shaft 1 . [0034] The pump shaft 1 has a shaft sleeve 12. The shaft sleeve 12 has symmetrical ends 14a, 14b. Each symmetrical end 14 has a first O-ring seal 16a, 16b abutting an enlarged section 18a 18b. In this manner, the section 20 of the shaft sleeve 12 extending between the enlarged sections 18a, 18b operates to create a gap 22 between it and the pump shaft 1 . This is best shown in Figure 3.

[0035] The outer surface 24 of the shaft sleeve 12, in this embodiment, is polished to a mirror finish.

[0036] The sealing system 10 is shown in Figures 1 and 2. The sealing system 10 comprises a main body 26 and a cover plate 28. The main body 26 has an impeller end 30 and a back end 32. The cover plate 28 encapsulates the main body 26 at the impeller end 30.

[0037] The main body 26 comprises an attachment plate 34, an end plate 36 and a sealing cartridge 38. The attachment plate 34 has a plurality of apertures 40 spaced evenly about the periphery of the attachment plate 34 to allow the attachment plate 34 to be affixed to a bearing housing 2. More specifically, the attachment plate 34 is mechanically affixed to the bearing housing 2 by way of bolts (not shown) that thread into threaded apertures (also not shown) provided in the bearing housing 2.

[0038] The attachment plate 34 is connected to the end plate 36 by way of a plurality of connectors 42. Each connector 42 extends from a position about the periphery of the attachment plate 34 to a similar position about the periphery of the end plate 36 at a first side 44.

[0039] Both end cover 80 and the end plate 36 have a central bore 46a, 46b. Central bore 46a of the end cover 80 is of a size slightly larger than the diameter of the pump shaft 1 . Central bore 46b of the end plate 36 is significantly larger than the diameter of the pump shaft 1 .

[0040] Extending from a second side 48 of the end plate 36 is a peripheral wall 50. The peripheral wall 50 extends from the end plate 36 in a direction axially aligned with that of the connectors 42. In this manner, the first side 44 and second side 48 are opposing planar sides of the end plate 36. [0041] The peripheral wall 50 has an abutment ring 52 at its base 54. The role of the abutment ring 52 and the peripheral wall 50 will be described in more detail below.

[0042] The sealing cartridge 38 takes the form of a housing 56 having a first section 58 and a second section 60. The housing 56 has a bore 62 extending therethrough to receive the pump shaft 1 and shaft sleeve 12. The total length of the housing is slightly less than the length of the shaft sleeve 12.

[0043] The outer wall 64a of the first section 58 is cylindrical in shape. The diameter of the first section 58, inclusive of the bore 62, is substantially equal to the diameter of the central bore 46b. Similarly, the outer wall 64b of the second section 60 is also cylindrical in shape. The diameter of the second section 60, inclusive of the bore 62, is just less than the diameter of the peripheral wall 50. The length of the second section 60 is substantially equal to the distance between open end 66 of the peripheral wall 50 and the abutment ring 52.

[0044] A channel 70 is provided in the outer wall 64b at a position proximate its distal end 68. The channel 70 is sized and shaped so as to receive a second “O”-ring seal 72.

[0045] The second section 60 also has an impeller side 74. The impeller side 74 has a recessed section 76 and a ring wall 78. The role of the recessed section 76 and ring wall 78 will be explained in more detail below.

[0046] An end cap 80 is removably attached to the first section 58 by way of a plurality of screws 82. In this manner, the end cap 80 provides axial access to a sealing recess 84 that extends below both the first section 58 and the second section 60 of housing 56. The end cap 80 also has a pinpoint aperture 81 provided therein.

[0047] Located in the first section 58 are two lubricant apertures 86a, 86b. Each lubricant aperture 86a, 86b extends from an outer surface of the housing 56 through to the sealing recess 84. A threaded seal fitting 88 is received within each lubricant aperture.

[0048] Similarly, located in the second section 60 is a grease aperture 90. The grease aperture 90 extends from the outer surface of the housing 56 through to the sealing recess 84. A threaded seal fitting 88 is again received within the grease aperture 90.

[0049] A fluid recovery pipe 92 is connected at one end to the threaded seal fitting 88 received in lubricant aperture 86a. A fluid delivery pipe 94 is connected at one end to the threaded seal fitting 88 received in lubricant aperture 86b. The remaining end of each of the fluid delivery pipe 92 and fluid recovery pipe 94 is connected to a lubricant reservoir 96.

[0050] A grease delivery pipe 98 is connected at one end to the threaded seal fitting 88 received in grease aperture 90. The remaining end of the grease delivery pipe 98 is connected to a grease reservoir 100.

[0051] The sealing recess 84 houses a plurality of lantern rings 102, a plurality of single lip seals 104, a double lip seal 106, and a restrictor bush 108. At least one aperture (not shown) in a lantern ring 102 is in co-axial alignment with one of the threaded seal fittings 88.

[0052] In this embodiment, three single lip seals 104 are tightly located in the sealing recess 84 in the space between the lantern rings 102 proximate the lubricant apertures 86a, 86b and the lantern ring 102 proximate the grease aperture 100. Each single lip seal 104 comprises a positioner 110 and a seal 112. The lip seals 104 are further divided by a spacer ring 113.

[0053] To elaborate, the positioner 110 comprises two “L”-shaped flanges 114a, 114b. Flange 114a is approximately twice the width and height of flange 114b. Each flange 114 has a first side 116 and a second side 118.

[0054] First side 116 of flange 114b makes full contact with first side 116 of flange 114a and is positioned such that a free end 120 of each is substantially coterminus. This results in second side 118 of flange 114b being spaced from second side 118 of flange 114a, thereby defining a gap 122.

[0055] The seal 112 is a ring seal having a rounded “L”-shaped cross-section as shown best in Figure 5. As shown in this Figure, the seal 112 has a contained section 124 and a free section 126. The contained section 124 is received within the gap 122 and retained in place by way of friction. The free section 126 makes contact with the shaft sleeve 12 when the shaft sleeve 12 is received within the bore 62. [0056] The double lip seal 106 is shown in Figure 5. The double lip seal 106 is positioned between the lantern rings 102 proximate the lubricant apertures 80a, 80b and the end cap 80.

[0057] In this embodiment, the double lip seal 106 comprises a base block 128 having two lips 130 extending therefrom. Lip 130a extends from the side of the base block 128 closest to the shaft sleeve 12 at a position adjacent end cap 80. Lip 130b extends from the side of the base block 128 closest to the shaft sleeve 12 at a substantially central position thereto. Both lips 130a, 130b have grease applied to them on installation. The base block 128 also has a recessed channel 129 provided therein. A second “O”-ring 131 is received within the recessed channel. The base block 128 is also adapted to receive that section of a pin (not shown) that passes through the pinpoint aperture 81 in the end cap 80.

[0058] When the shaft sleeve 12 is received within the bore 62, lip 130a acts to close off the gap 132 in the bore 62 that remains between the shaft sleeve 12 and the end cap 80. Lip 130a makes contact with the shaft sleeve 12 and extends along its length in the direction towards the attachment plate 34. Lip 130b also makes contact with the shaft sleeve 12 and extends a minimal distance along its length in the direction towards the second section 60.

[0059] The restrictor bush 108 is positioned between the lantern ring 102 proximate the grease aperture 90 and the housing 56 which includes the impeller side 76. The restrictor bush 108 of this embodiment, comprises a prop 134 from which two ringed walls 136a, 136b project. Ringed wall 136a projects towards, and makes contact with, the housing 56 proximate the impeller side 74. Ringed wall 136a is substantially in coaxial alignment with the pump shaft 1 .

[0060] Ringed wall 136b projects at an angle towards the shaft sleeve 12 and makes contact with the shaft sleeve 12 when assembled. However, due to the material from which the restrictor bush 108 is formed, this contact does not generate any real amount of friction (if any). Ringed wall 136b also projects towards the housing 56 proximate the impeller side 74, but does not make contact with it. In doing so, the two ringed walls 136a, 136b define an enclosed space 138 and a gap 140. [0061] A rotational connector 142 is arranged so as to be positioned proximate the impeller side 74. The rotational connector 142 has a first segment 144 and a second segment 146. A bore 148 also extends internally through the first segment 144 and second segment 146 and is configured to be concentric with bores 46. The exterior surface 150 of the first segment 144 is cylindrical. The second segment 146 has a rounded exterior shape.

[0062] The first segment 144 has an abutting face 154. The abutting face 154 is sized to match the impeller sleeve 3. Located within the abutting face 154 is a recess channel 156. The recess channel 156 houses a third “O”-ring seal 158.

[0063] Protruding equidistantly about the exterior of the second segment 146 are a plurality of blades 160. Each blade 160 is straight and angles from a point proximate the periphery of the second segment 146 to a point proximate the periphery of the first segment 144.

[0064] Located in the interior of the second segment 146 is a channel 162. The channel 162 is sized and shaped to be slightly larger in length and height than the ring wall 78.

[0065] The cover plate 28 has three sections 164a, 164b, 164c. The cover plate 28 also has an interior surface 166 and an exterior surface 168. The exterior surface 168 of section 164b is raised (i.e. of greater height) relative to the exterior surface 168 of sections 164a and 164c. Similarly, exterior surface 168 of section 164c is raised relative to exterior surface 168 of section 164a.

[0066] Located in the interior surface 166 of section 164b are recess channels 170. In this embodiment, a recess channel 170 is positioned either side of the midpoint of section 164b. Each recess channel 170 houses a fourth “O”-ring seal 172.

[0067] This embodiment of the invention will now be described in the context of its intended use. However, before doing so, it is important to note certain features of a pump 4 not already described that make use of the sealing system 10.

[0068] The pump 4 incorporates bearing housing 2 and a frame plate 5 as would be readily known to the person skilled in the art. As the function of both components has no relevance to the invention, they will not be described in more detail here. [0069] The pump shaft 1 terminates in a threaded section 6. The threaded section 6 engaged with a corresponding threaded section of an impeller 7. A frame plate liner insert 8 surrounds the area of connection between the impeller 7 and the pump shaft 1 and thus shields the pump 4 generally from the pumped fluid.

[0070] Surrounding the pump shaft 1 at a location appropriately spaced from the threaded section 6 is a bearing spacer 9.

[0071] To install the sealing system 10 of the present embodiment, the sealing cartridge 38 initially has nothing installed in the sealing recess 84. The operator (not shown) then uses appropriate tooling to remove screws 82 and thus allow the end cap 80 to also be removed. This gives the operator access to the sealing recess 84.

[0072] The operator then acts to install the restrictor bush 108 into the sealing recess 84 and manipulate it until such time as ringed wall 136a makes contact with the housing 56 proximate the impeller side 74. Once so positioned, a first lantern ring 102 is installed and manipulated to a position where:

• it is adjacent the restrictor bush 108; and

• at least one aperture in the lantern ring 102 is in coaxial alignment with the threaded seal fitting 88 located in the grease aperture 90.

[0073] Following on from the first lantern ring, each of the three single lip seals 104 are installed. The first single lip seal 104 also abuts the first lantern ring 102, while each successive single lip seal 104 neighbours its predecessor single lip seal 104. In between the installation of each single lip seal 104 a spacer ring 113 is installed. Furthermore, following installation of each single lip seal 104, lubricant and/or grease is syringed into the open spaces 180 formed during installation.

[0074] A second lantern ring 102 is then installed into the sealing recess 84. As with the first lantern ring 102, the second lantern ring 102 is manipulated to a position where:

• it is adjacent the last installed single lip seal 104; and

• at least one aperture in the lantern ring 102 is in coaxial alignment with (a) the threaded seal fitting 88 located in lubricant aperture 86a; and (b) the threaded seal 88 fitting located in lubricant aperture 86b. [0075] The double lip seal 106 is then installed with the channel 129 and “tyring 131 facing outwards (i.e.. away from the pump shaft 1 ). It is to be noted that prior to installation, each lip 130a, 130b have grease applied to the underside thereof (i.e. the side that will face the pump shaft 1 ). Additionally, the double lip seal 106 is installed so as to abut the second lantern ring 102. The end cap 80 is then reinstalled and secured in place by way of screws 82. A pin (not shown) is then installed through the pinpoint aperture 81 into the base block 128 to prevent rotation of the double lip seal 106 during operation.

[0076] The shaft sleeve 12 is then placed over the pump shaft 1 at the threaded section 6 and directed along the pump shaft 1 until it makes contact with bearing spacer 9. The main body 26 is then installed over the top of the shaft sleeve 12.

[0077] Correct installation of the main body 26 involves receiving the shaft sleeve 12 and pump shaft 1 in central bores 46a, 46b. Furthermore, the main body must be aligned such that the attachment plate 34 can abut the bearing housing 2. This is important as the subsequent mechanical fixing of the attachment plate 34 to the bearing housing 2 operates to axially align the sealing system 10 with the pump shaft 1 .

[0078] When properly positioned, the following occurs:

• ringed wall 136b makes contact with the shaft sleeve 12;

• free section 126 of each of the single lip seals 104 also makes contact with the shaft sleeve 12, the portion of the free section 126 making contact with the shaft sleeve 12 being directed towards the impeller 7;

• lip 130b makes contact with the shaft sleeve 12, the portion of the lip 130b making contact with the shaft sleeve 12 being directed towards the impeller 7; and

• lip 130a makes contact with the shaft sleeve 12, the portion of the lip 130a making contact with the shaft sleeve 12 being directed towards the bearing housing 2.

[0079] The cover plate 28 is then installed over the end plate 36. Correct positioning of the cover plate 28 requires section 164b to abut the frame plate 5. [0080] The rotational connector 142 is then installed about the pump shaft 1. When properly positioned, the interior of second segment 146 makes contact with a symmetrical end 14b of the shaft sleeve 12 and, in particular, the “O”-ring seal 16b located therein. This ensures that the interior of second segment 146 does not make contact with the impeller side 74 and that ring wall 78 similarly does not make contact at any point with channel 162.

[0081] The frame plate liner insert 8 is then installed. A cushioning element (not shown) positioned between the rear face of the frame plate liner insert 8 acts to cushion the cover plate 28 when properly positioned and ensures proper compression of the sealing system 10 to facilitate efficient operation. The impeller 7 is then installed, with the impeller shaft 3 making contact with the abutting face 154. Tightening of the impeller 7 about the threaded section 6 also operates to ensure proper compression of the sealing system 10 to facilitate efficient operation.

[0082] This completes assembly of the sealing system 10 to the pump 4.

[0083] Once assembled, sealing system 10 operates as follows during normal operation of the pump 4.

[0084] Rotation of the pump shaft 1 causes the impeller 7 to rotate and thus generate the desired pumping action in the pumped fluid. Due to the compressive engagement of impeller 7 to rotational connector 142, rotational connector 142 also rotates along with the pump shaft 1 and the impeller 7. This compressive engagement also causes the shaft sleeve 12 to rotate.

[0085] As the rotational connector 142 rotates, the blades 160 provided in the exterior surface directs pumped fluid that is able to pass through the gap between the impeller 7 and the frame plate liner insert 8 towards distal end 68 of the outer wall 64. Gravity then acts on particles entrained in the pumped fluid, causing the particles to fall towards the bore 148. The falling particles again interact with the blades 160 to again be directed to the distal end 68. In doing so, a turbulent effect is created about the location of the recessed section 76.

[0086] Pumped fluid that escapes the turbulence created in the recessed section 76 to seek further ingress towards the sealed area of the pump 4 enters the flow path 174. As mentioned above, the flow path 174 (which in cross section as a square wave path in Figure 3b) is formed by the space between the interior of the rotational connector 142 and impeller side 74 (as deviated by the gap created by the space between ring wall 78 and channel 162). This flow path 174 acts to trap physical contaminants in the pumped fluid that seeks to enter the sealed area of the pump 4. Viewed from a different perspective, this also means that the path seeks to prevent contaminants in the pumped fluids from damaging the lip seals 104, 106.

[0087] However, to the extent that pumped fluid is able to follow the flow path 174 back towards the sealed area of the pump 4, the pumped fluid passes through the space between the impeller side 74 and the shaft sleeve 12 to gap 140 and, eventually, enclosed space 138. Ringed wall 136b, by making contact with the shaft sleeve 12, seeks to prevent this pumped fluid from actually entering any other part of the sealing recess 84.

[0088] Ringed wall 136b also acts as a containment wall for a grease chamber 176 and thereby restrict the flow of the grease contained therein along the flow path 174. The grease chamber 176 is further defined by the lantern ring 102 proximate the grease aperture 90. The grease reservoir 100, by way of grease delivery pipe 98, fills (or refills) the grease chamber 176 with grease at periodic intervals. In this embodiment, the grease is insoluble, inert and resilient. Ideally, the grease is an EP- 2 viscous grease.

[0089] By using grease having these characteristics, the grease coats the first lip seal 104 in a manner that provides protection against caustic material in the pumped fluid. The grease also operates to stop precipitation from happening on the surface of the lip seal 104.

[0090] The grease chamber 176 also operates as a last line of defence against the pumped fluid. To the extent that the pumped fluid that is able to reach this location still contains any physical contaminants, these contaminants become suspended in the grease contained within the grease chamber 176.

[0091] Over time, the grease in the grease chamber 176 will be pushed back through the space between the impeller side 74 and the shaft sleeve 12 to the flow path 174 for reasons described further below. Grease that passes through the flow path 174 is directed by the ring wall 78 towards the impeller. [0092] It is to be noted that as the grease travels along the flow path 174 it acts as a clogging agent and thus restricts pumped fluid from flowing back to the sealing cartridge 38, etc due to its viscous nature. However, each new dosage of grease delivered to the grease chamber 176 causes further movement of the grease already in the flow path 174 towards the impeller 7where it is then dispersed into the pumped fluid.

[0093] While the dispersal of grease into the pumped fluid is an additional contaminant that must be dealt with downstream, during anticipated operation, the quantity of grease expected to be dispersed into the pumped fluid is in the order of 250ml per month and thus negligible in context.

[0094] Simultaneous with the operation of the pump 4, the lubricant reservoir 96 feeds lubricant to the sealing recess 84 under the force of gravity by way of the fluid delivery pipe 94 and its associated threaded seal fitting 88 and lantern ring 102. The delivered lubricant extends towards the rotational connector 142 and tries to extend towards the end cap 80.

[0095] In this embodiment, to operate as described, it is important to note that the pressure of the lubricant must be equal to, or less than, the pressure of the pumped fluid.

[0096] As the lubricant extends towards the rotational connector 142, it applies pressure to the free section 126 of each single lip seal 104. As each single lip seal 104 is secured in place by way of contained section 124, this pressure causes the free section 126 to lift to allow a small amount of lubricant to travel to the next single lip seal 102/grease chamber 176 before returning into place. As the lubricant travels between lip seals 104 to the grease chamber 176 it also operates to lubricate the underside of the free section 126 and create a meniscus between the lip seal and the shaft sleeve 12. The presence of this meniscus, in combination with vibrations generated during the normal operation of the pump, in effect causes the lubricant to be “reverse pumped” along the shaft sleeve 12 until it enters the grease chamber 176.

[0097] When the lubricant enters the grease chamber 176 it is absorbed by the grease contained therein, where it is ultimately discharged into the pumped fluid in the manner as described above. [0098] Lubricant that tries to extend towards the end cap 80 is prevented from doing so by the arrangement of lip 130b. Specifically, lip 130b is positioned such that the weight of the lubricant seeks to reinforce the connection between the lip 130b and the shaft seal 12. Due to each of lips 130a, 130b already having had grease applied to its underside, a meniscus is already present between the lips 130a, 130b and the shaft sleeve 12 even prior to operation.

[0099] Unlike the meniscus formed between the free section 126 of each lip seal 104 and shaft sleeve 12 which is constantly being regenerated through the supply of new lubricant, the meniscus formed between lips 130a, 130b and the shaft sleeve 12 remains as is as the grease used to form the meniscus is not reapplied after installation.

[0100] In this manner, while the lubricant does seek to extend outwards, in the main it is contained in the ringed area 178 between lip 130b and the adjacent single lip seal 104 until dispersed by way of the “reverse pump” effect described above. While contained, friction from the operation of the pump causes the lubricant to increase in temperature.

[0101] To elaborate, the shaft seal 12 is made from a material that has good heat transfer properties. This results in heat being transferred to the lubricant. Dispersal of this heat is achieved in four ways, namely:

• by transfer through the components of the sealing system 10 to the atmosphere;

• by transfer through the components of the sealing system 10 to the metal components of the pump 4;

• by way of the discharged grease to the pumped fluid; and

• to the lubricant reservoir 96 by way of the fluid recovery pipe 92 in situations where the amount of heat generated is sufficient to create a natural thermosiphon effect.

[0102] Thus, the sealing system 10 has a further benefit in its ability to provide additional avenues for the pump to disperse generated heat.

[0103] The automatic recovery of fluid in this manner has a further advantage in that the lubricant in the lubricant reservoir 96 is a good illustration of the state of the lubricant in the sealing recess 84. Thus, if the lubricant reservoir 96 shows elements of contamination, the operator can assume that the sealing recess 84 similarly has contaminants entering therein and take appropriate action to prevent this from happening or repair the sealing system 10.

[0104] Over time, as adjustments need to be made to the positioning of the impeller 7, the operator merely need adjust the position of the bearing housing 4 as would be readily known to the person skilled in the art. The physical connection between the attachment plate 34 and the bearing housing 4, means that repositioning of the bearing housing 4 causes a corresponding re-positioning of the components of the sealing system 10 other than the cover plate 28. To elaborate, the cover plate 28 always remains in a static position - rather the peripheral wall 50 slides relative to the cover plate 28.

[0105] It is to be noted here that the bearing housing 4 is adjusted so as to move in the direction of the impeller 7 to account for wear. This means that the peripheral wall 50 similarly only slides relative to the cover plate 28 in this same direction. This restriction also means that the fourth “O”-ring seals 172 are always presented to a clean surface.

[0106] In accordance with a second embodiment of the present invention, where like numerals reference like parts, there is a sealing system 200 for a pump shaft 1 . For the sake of brevity, only those aspects of this third embodiment that differ from the first embodiment will be described hereafter.

[0107] In this embodiment, the lubricant reservoir 96 is omitted and the fluid recovery pipe 92 and the fluid delivery pipe 94 are connected to the grease reservoir 100.

[0108] Rotational connector 142 is modified as shown in Figure 6. The modifications relate to a variation in the blades 160 so as to provide a more rounded base section 202 and recessed vanes 204.

[0109] The final modification to this third embodiment is the introduction of an additional ring wall 78. [0110] This embodiment of the invention will now be described in the context of its intended use. Again, for the sake of brevity, only those aspects relating to use of this third embodiment that differ from the first embodiment will be described.

[0111] As the rotational connector 142 rotates, the blades 160 provided in the exterior surface directs pumped fluid that is able to pass through the gap between the impeller 7 and the frame plate liner insert 8 towards distal end 68 of the outer wall 64. Gravity then acts on particles entrained in the pumped fluid, causing the particles to fall towards the bore 148. The falling particles again interact with the blades 160 to again be directed to the distal end 68. Additional particles are captured by the recessed vanes 204 which, due to the rotational force generated by rotational connector 142, are ultimately released from the recessed vanes 204 and directed, or flung, towards distal end 68.

[0112] In doing so, a turbulent effect is created about the location of the recessed section 76.

[0113] Pumped fluid that escapes the turbulence created in the recessed section 76 to seek further ingress towards the sealed area of the pump 4 enters the flow path 174. As with the first embodiment, this flow path 174 acts to trap physical contaminants in the pumped fluid that seeks to enter the pump 4. However, in this embodiment, multiple ring walls 78 are used to lengthen the flow path 174 and thus allow more particles to be captured within the grease that is conveyed therethrough.

[0114] Simultaneous with the operation of the pump 4, the grease reservoir 100 feeds pressurised to the sealing recess 84 by way of the fluid delivery pipe 94 and its associated threaded seal fitting 88 and lantern ring 102. The delivered grease extends towards the rotational connector 142 and tries to extend towards the end cap 80.

[0115] In this embodiment, to operate as described, it is important to note that the grease only need be pressurised to a level necessary to facilitate injection to the sealing recess 84.

[0116] As the grease extends towards the rotational connector 142, it applies pressure to the free section 126 of each single lip seal 104. As each single lip seal 104 is secured in place by way of contained section 124, this pressure causes the free section 126 to lift to allow a small amount of grease to travel to the next single lip seal 102/grease chamber 176 before returning into place. As the grease travels between lip seals 104 to the grease chamber 176 it also operates to lubricate the underside of the free section 126 and create a meniscus between the lip seal and the shaft sleeve 12. The presence of this meniscus, in combination with vibrations generated during the normal operation of the pump, in effect causes the grease to be “reverse pumped” along the shaft sleeve 12 until it enters the grease chamber 176.

[0117] It is important to note that a key element of each of the above embodiments is the “reverse pumping” effect of the lubricant/grease that is facilitated by the creation of the meniscus on the shaft sleeve 12. As such, there is no direct contact between components such as the free section 126 of lip seals 104 and lips 130a, 130b of double lip seal 106 and the shaft sleeve 12 during normal operation of the pump 4. However, when not operating (or when operating in an abnormal condition such as dry operation), it is possible for components to make direct contact with the shaft sleeve 12. When this occurs, at least some of the advantages of the current invention are no longer achievable.

[0118] It is to be appreciated by the person skilled in the art that the embodiments of the invention described herein are embodiments of the invention as applied to end-suction pumps (i.e. those in which the impeller is attached to the end of the shaft and the sealing system 10 is attached to the bearing housing 2). Implementation of the invention in other pump systems which have the impeller in the middle of the shaft (e.g. split case pumps), the sealing system may be installed between the impeller and the bearing housings and attached to the stuffing box bore.

[0119] While each of the above embodiments has been described with reference to a double lip seal 106 to the side of the sealing recess 84 away from the impeller 7, this is merely one possible manner of sealing this end of the main body 26. In other configurations, the area to the side of the sealing recess 84 away from the impeller may simply be blocked and sealed by an appropriate structure or means. For instance, packing glands may be installed in place of the double lip seal 106. Alternatively, the appropriate structure may simply be the end cap 80.

[0120] It should be appreciated by the person skilled in the art that the above invention is not limited to the embodiments described. In particular, the following modifications and improvements may be made without departing from the scope of the present invention:

• [0121] The sealing system 10, 200 may be retrofitted to existing pumps 4 or be included as part of an OEM pump 4.

• [0122] The shaft seal 12 may be made from any hard material. For instance, the shaft seal may be made from hardened steel, silicon carbide or tungsten carbide.

• [0123] The outer surface 24 of the shaft sleeve 12 need not be polished to a mirror finish. Alternatively, the outer surface 24 may be finished to any level provided that there is an exceptionally low friction coefficient between the lip seals 104, 106 and the shaft sleeve 12.

• [0124] Each of the lip seals 104, 106 are to be made from low friction, low elasticity, high wear maintenance material. It is further preferred that the material used to form the lip seals 104, 106 is capable of handling temperatures in the order of 220°C.

• [0125] In one embodiment preferred by the applicant, the sealing components 126, 130 of the lip seals 104, 106 are made from polytetrafluoroethylene (PTFE). In an alternate embodiment preferred by the applicant, the sealing components 126, 130 of the lip seals 104, 106 are made from a combination of PTFE, glass and molybdenum disulfide.

• [0126] The lubricant may be any form of oil. The applicant has a preference for less viscous oils - such as those known as sewing machine oils. However, the applicant has also found that hydraulic oil can be used as the lubricant and is likely to be readily available at mineral processing sites.

• [0127] In a variation of the first embodiment, the lubricant is not pressurised and the lubricant is simply gravity fed to the sealing recess 84. Alternatively, to assist in preventing failure of the double lip seal 106, the lubricant may be maintained at atmospheric pressure or very slightly above atmospheric pressure (depending on the configuration of the pump 4, lubricant used, etc.)

• [0128] The grease may be other than an EP-2 viscous grease provided that it meets the other criteria set out above. For example, the grease may be a rheopectic sealing paste. • [0129] The grease may be imbued with PTFE or other filler to create a more paste like substance.

• [0130] The applicant has found that the system is capable of operation with grease being dosed at a regular rate of 2.5 shots per day, with each shot amounting to 1 ml of grease. However, it should be appreciated that other dosage rates and quantities may be needed depending on operational circumstances.

• [0131] The sealing system 10, 200 may be modified to include more or less first lip seals 104 than that described in the above embodiments.

• [0132] Relevant elements forming the positioner 110 may be made from marine grade stainless steel.

• [0133] The shaft sleeve 12 may make full contact with the shaft 1 along its length.

• [0134] The sealing cartridge 38 may be pre-assembled with the lantern rings 102, lip seals 104, 106 and restrictor bush 108. In a further configuration, the sealing system 10, 200 may be completely pre-assembled.

• [0135] Alternatively, the sealing cartridge 38 may be a sealed unit (i.e. the end cap 80 may not be removable).

• [0136] Other means of affixing the attachment plate 34 to the bearing housing 2 may be used. For instance, the attachment plate 34 may be magnetically connected to the bearing housing 2.

• [0137] The sealing cartridge 38 may come in a variety of sizes and dimensions. Similarly, the sealing system 10, 200 and the sealing recess 84 may also come in a variety of sizes and dimensions.

• [0138] The restrictor bush 108 may be omitted or replaced with a functionally equivalent element of a different configuration.

• [0139] The lubricant reservoir 96 may be omitted. Similarly, the grease reservoir 100 may be omitted. Both may be replaced with manual arrangements for delivering lubricant and/or grease to the sealing system 10, 200.

• [0140] The threaded seal fittings 88 may take different configurations to that described in this specification. • [0141] The lubricant apertures 86a, 86b may be in different planes to each other, provided that both apertures are in fluid communication with each other such that lubricant delivered by way of lubricant aperture 86a is able to exit by way of lubricant aperture 86b.

• [0142] The recessed “O”-ring seals 16, 72, 158, 172 may be replaced with other recessed sealing arrangements.

• [0143] Other arrangements which facilitate removal of the end cap 80 may be used. For instance, the end cap 80 may be magnetically connected to the sealing cartridge 38.

• [0144] The cover plate 28 may be fixed in place relative to the main body 26 such that neither moves relative to each other.

• [0145] The fluid delivery pipes 92, 94, 98 may be reconfigured or omitted to allow other forms of delivery of lubricant and/or grease to the sealing system 10, 200.

• [0146] Configurations of lip seals 104, 106 may differ from that described above. For instance, the double lip seal 106 may be replaced with two single lip seals 104.

• [0147] The blades 160 may be omitted. Alternatively, the blades 160 may take different configurations to that described. For instance, the blades 160 may be angled to create additional turbulence or direct pumped fluid towards a specified area other than the distal end 68.

• [0148] Other configurations of flow path 174 may be adopted. These flow paths 174 may not lead to the enclosed space 138. However, it is important that the flow path 174 doubles back on itself at least once around a ring wall 78 to act as a trap for physical components contained in the pumped fluid. As examples of alternative flow path shapes that meet this criteria, the flow path, in cross-section, may have a more trapezoidal form or even be akin to a sine wave.

• [0149] The lubricant reservoir 96 may incorporate a breathing cap to facilitate delivery of the lubricant and allow for replenishment of lubricant as required. Similarly, the grease reservoir 96 may incorporate a grease nipple to allow for replenishment of grease. • [0150] In situations where the sealing system 10, 200 is not able to achieve a natural thermosiphon effect, circulation of the lubricant may be assisted through the use of a recirculating pump (not shown).

• [0151] The restrictor bush 108 may be omitted. Alternatively, multiple restrictor bushes 108 may be employed.

• [0152] The restrictor bush 108 may be made of PTFE.

• [0153] The restrictor bush 108 may adopt different configurations from that described above. For instance, the restrictor bush 108 may take a reversed configuration to that described above for use in vacuum pumps.

• [0154] The single lip seals 104 may incorporate a backing seal. The backing seal may be used where the contained section 124 is narrower than the gap 122. In this manner, the backing seal is used to occupy the remaining space in the gap 122 to ensure frictional retention of the contained section 124.

• [0155] While the invention describes perfect alignment of the lantern rings 102 relative to the threaded seal fittings 88, this is not necessary for the invention to work.

• [0156] An additional “O”-ring may be installed above ringed wall 136a to further act as a preventative sealing measure against ingress of pumped fluid.

• [0157] Exterior surface 150 may have an angled leading edge to further assist in preventing erosion.

• [0158] “O”-rings 172 may be omitted entirely, or reduced to a singular “O”-ring 172.

• [0159] The second embodiment of the invention may be modified to continue using lubricant and grease in the same manner as described in the first embodiment. In such a configuration, as with grease, the heavier the lubricant used the faster the “reverse pumping” action of the single lip seals 104.

• [0160] While it is considered the best configuration for the sealing arrangement and contaminant containment system to be used in conjunction, this is not required. The sealing arrangement may be used with other systems for containing contaminants entrained in the pumped fluid. Similarly, the contaminant containment system may be used with other systems for sealing the pump 4. • [0161] Lubricant aperture 86b may be replaced with a venting aperture. In such a configuration, the threaded seal fitting 88 is retained but is now connected to an air venting pipe. The air venting pipe can be in fluid communication with the lubricant reservoir 96 or grease reservoir 100 or can be capped by an air filter before being vented to the atmosphere. In this manner, there is no recirculation of lubricant or grease.

• [0162] Abutting face 154 need not be sized to match the impeller sleeve 3. In alternative configurations, the abutting face 154 may be larger or smaller than the impeller sleeve 3.

• [0163] The cover plate 28 may vary in size as is required to meet other pump sizes and types. However, in each case the purpose of the cover plate 28 is to adapt the rubber seal gasket of that pump to the dimensions of the main body 26 and the frame plate 5.

• [0164] In other embodiments, the cover plate 28 may be configured with a single recess channel 170 housing a fourth “O”-ring seal 172.

• [0165] While the invention has been described in the context of the lantern ring 102 being in co-axial alignment with threaded seal fittings 88, depending on the configuration of the lantern ring 102 such alignment is not necessary if it is still possible for lubricant and/or grease to pass through the lantern ring 102 to the appropriate aperture 86, 90.

• [0166] In a preferred arrangement, the fluid delivery pipe 94 and fluid recovery pipe 92 are located at angles of 180° to each other relative to the bore 148. In another arrangement, the fluid delivery pipe 94 may be located at a angle of 90° to the fluid recover pipe 92 relative to the bore 148.

• [0167] Either embodiment may be modified to allow for multiple fluid delivery pipes 94.

[0168] It should be further appreciated by the person skilled in the art that the invention is not limited to the embodiments described above. Additions or modifications described, where not mutually exclusive, can be combined to form yet further embodiments that are considered to be within the scope of the present invention.