SE2350064A1 - A liner arrangement for a centrifugal pump for processing slurries - Google Patents

Abstract

The disclosure relates to a liner arrangement (1) for a centrifugal pump (2) for processing slurries, the centrifugal pump (2) comprising an impeller and a drive shaft (6) connected with a back portion of the impeller (3). The liner arrangement comprises a back liner (10) arrangeable around at least the back portion of the impeller and around the drive shaft, and a complementary liner (20) arrangeable at the drive shaft and at a central back portion (5) of the impeller (3). The back liner comprises an inclined back liner portion (11) providing an inclined back liner surface (12) and the complementary liner (20) comprises an inclined complementary liner surface (22). The inclined back liner surface (12) is opposite the inclined complementary liner surface (22). The liner arrangement (1) is configured to provide a channel (30) between the inclined back liner surface (12) and the inclined complementary liner surface (22). The disclosure further relates to a centrifugal pump (2) for processing slurries comprising the sealing arrangement.

Description

Field of the disclosure The present disclosure relates to a liner arrangement for a centrifugal pump for processing slurries providing a sealing effect for the drive shaft, and a centrifugal pump for processing slurries comprising such a liner arrangement.

Background art A centrifugal pump is a type of rotodynamic pump that uses a rotating impe||er to increase the pressure and flow rate of a fluid. The impe||er is supported on a shaft which is rotated by an external motor for rotating the impe||er, also referred to herein as a drive shaft, and is housed within a pump casing having an inlet and an outlet. ln operation, fluid enters the pump through the inlet and is propelled outwardly by a centrifugal force generated by the rotating impe||er. The fluid flowing through the impe||er blades is accelerated by the centrifugal force and exits the pump through the outlet at a higher pressure and flow rate than when it entered the pump.

Centrifugal pumps are commonly used in a wide range of applications, including water treatment, irrigation, and for transporting and processing slurries. They are well-suited for handling large volumes of liquid at relatively low pressures and are highly efficient. A challenge, however, with centrifugal pumps used for transporting and processing slurries, also referred to herein as slurry pumps, is that in operation, abrasive particles present in the slurry may cause wear of the parts of the pump that enter into contact with the processed slurry. Therefore, centrifugal pumps are typically provided with one or several liner elements made of a wear resistant material. The liner elements thus act as a barrier between the pump components and the abrasive or corrosive fluids being pumped, reducing the amount of wear and tear on the pump parts. This helps extending the lifetime of the pump parts and reduces the need for maintenance and repairs. lt is also important to prevent the slurry processed by the pump from leaking at the back side of the pump, where the impe||er is supported on the drive shaft, and thus to sea| the drive shaft from the processed fluid. This area may be referred to as the shaft sea| area. ln case of Ieakage of slurry at the back of the pump, partic|es in the processed slurry may get stuck in corners or small passages causing undesired wear and, over time, the number of partic|es may build up to such an extent that it may affect the efficiency of the centrifugal pump. This is highly undesirable and, should it happen, requires repair and maintenance stops.

Summary lt is an object to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination and solve at least the above-mentioned problem.

According to a first aspect, there is provided a liner arrangement for a centrifugal pump for processing slurries, the centrifugal pump comprising an impe||er and a drive shaft connected with a back portion of the impe||er, the liner arrangement comprising; a back liner arrangeable around at least the back portion of the impe||er of the centrifugal pump and around a circumferential portion of the drive shaft, a complementary liner arrangeable at a circumferential end portion of the drive shaft and at a central back portion of the impe||er, wherein the back liner comprises an inclined back liner portion providing an inclined back liner surface and the complementary liner comprises an inclined complementary liner surface, wherein the inclined back liner surface is opposite the inclined complementary liner surface, and wherein the liner arrangement is configured to provide a channel between the inclined back liner surface and the inclined complementary liner surface.

A realisation by the inventors is that the liner arrangement creates a centrifugal force that helps preventing particles, from a slurry processed by the centrifugal pump, from getting stuck at the back side of the centrifugal pump, behind the impe||er. Typically, the area behind the impe||er, at the back side of the pump where the impe||er is supported on the drive shaft, is flooded with processed liquid when the centrifugal pump is stopped, e.g. during maintenance. To prevent further leakage of processed liquid along the drive shaft, a stuffing box is arranged thereat adjacent the portion of the back liner extending around the drive shaft. When the pump is in operation again, the processed liquid typically remains in the flooded area leading up to the stuffing box and abrasive particles present in the liquid may cause wear thereat. The inventors surprisingly found that by adapting a portion of the back liner such to provide an inclined portion, e.g. by bending back the back liner portion adjacent to the drive shaft, and by adding a complementary liner as described herein, such remaining liquid can effectively be led out from the shaft seal area and back into the pump chamber. The liner arrangement thereby provides a sealing effect which is efficient and cost-effective.

The complementary liner is advantageous in that it rotates with the drive shaft and the impellerwhen used in a centrifugal pump in operation, generating a centrifugal force that pushes any processed slurry present in the shaft seal area back into the ordinary flow around the impe||er through the channel provided between the inclined back liner surface and the inclined complementary liner surface. The centrifugal force further prevents slurry from leaking from the pump chamber to the shaft seal area during operation of the centrifugal pump. This reduces the wear of the drive shaft and thereby the wear of the centrifugal pump. With less wear the need for maintenance is reduced, providing a longer lifetime for the centrifugal pump, which is advantageous.

The back liner is further advantageous as it protects the centrifugal pump from wear occurring during normal operation and it may further be adapted to be used with corrosive fluids. lf the drive shaft and the impe||er are not properly protected from corrosion, it can cause damage and reduce the performance and efficiency of the centrifugal pump. The complementary liner may protect the portion of the impe||er that is connected to the drive shaft, further reducing wear of both the drive shaft and the impe||er, thus prolonging the lifetime of the centrifugal pump.

The back liner may be mounted on a back portion of a casing of the centrifugal pump in which the impe||er is housed. The back liner mainly protects a back portion of the casing from wear. lt is understood herein that with the back liner being arranged around the drive shaft it is meant that it circumferentially encloses a portion of the drive shaft without necessarily being in direct contact with the drive shaft.

The impe||er used for the centrifugal pump may be a closed type impe||er or a semi open type impe||er.

According to some embodiments, the back liner further comprises a first back liner portion arrangeable around a circumferential portion of the drive shaft of the centrifugal pump, a second back liner portion arrangeable around at least the back portion of the impe||er of the centrifugal pump, and the inclined back liner portion configured to connect the first back liner portion with the second back liner portion.

The back liner with the first back liner portion, the second back liner portion and the inclined back liner portion is advantageous in that it provides a flexibility in how the back liner may be provided. The requirements of the back liner may be different in the different portions. For example, different shapes, materials, or thicknesses may be preferred at different portions of the back liner. As an example, the first back liner portion may be subjected to less wear than the second back liner portion. ln such a case, the first back liner portion may be provided with less wear resistance than that of the second back liner portion. However, in view of this disclosure, the skilled person understands that the three portions may be produced having the same material and thickness. ln some embodiments, the back liner with the first back liner portion, the second back liner portion and the inclined back liner portion may be provided by bending back the inner central portion of the back liner. ln some embodiments, the back liner comprises the second back liner portion and the inclined back liner portion and is arrangeable at the drive shaft immediately adjacent a sealing such as a stuffing box. That is, an end portion of the inclined back liner portion is arrangeable at the drive shaft between the sealing and the impeller, which sealing provides further sealing of the drive shafi.

The radial extension of the impeller and the axial extension of the drive shaft are perpendicular to each other such that the inclined back liner portion bridges an angular difference between the first back liner portion and the second back liner portion. The inclined back liner portion may be linear or have a curvature that bridges the gap between the first back liner portion and the second back liner portion.

According to some embodiments, the first back liner portion comprises a sealing configurable to extend from a surface portion of the first back liner portion to a circumferential surface portion of the drive shaft such to seal a space therebetween. Thus, according to such an embodiment, the first back liner portion is integrated with a sealing, such as a stuffing box. lt may be advantageous to seal the space between the first back liner portion and the drive shaft to prevent leakage of slurry along the drive shaft. Such leakage may otherwise cause wear on the drive shaft or enter parts of the centrifugal pump that is not protected by liners. Providing a sealing that is integrated with the first back liner portion is further advantageous in that potentially leaked slurry will be forced through the channel between the inclined back liner surface and the inclined complementary liner surface by the centrifugal force created by the liner arrangement when the complementary liner rotates with the impeller during operation of the centrifugal pump. Additionally, when the centrifugal pump is not operated, the sealing provides a seal against the drive shaft, nonetheless.

The sealing may be of a low friction material. The sealing may thus be in contact with the drive shaft to fully seal a space between the first back liner portion and the drive shaft.

According to some embodiments, the inclined back liner surface comprises one or more grooves. With one or more grooves at the inclined back liner surface the inclined back liner portion will further enhance the effect of the centrifugal force pushing slurry out from the space behind the impeller. The grooves are shaped such to guide slurry out from the space behind the impeller. The rotation of the complementary liner will force leaked slurry with particles into the grooves wherefrom it will be pushed in the direction of the grooves and through the channel back into the pump chamber.

According to some embodiments, the one or more grooves extend helically along the inclined back liner surface, thus providing one or more helical grooves for guiding a flow into the pump chamber.

The helical extension of the one or more grooves may be advantageous as it ensures the effect that the material and the slurry follow the groove out from the space behind the impeller and towards the pump. That is, the centrifugal force created by the rotation of the complementary liner in combination with the helical extension of the groove generate a rotation direction pushing slurry towards the pump chamber. Thus, the one or more grooves may have a screw shape with a rotation direction pushing the slurry back towards the pump chamber and away from the space behind the impeller, i.e. the shaft seal area. ln an embodiment, the inclined back liner surface comprises one groove that extends from one end of the inclined back liner surface to a second, opposing, end of the inclined back liner surface. ln an embodiment, the inclined back liner surface comprises more than one groove.

According to some embodiments, the one or more grooves have a groove depth of 1-13 mm. With a groove depth of 1-13 mm, a good balance between the amount of material transported and the centrifugal force that reaches the material in the grooves may be achieved.

According to some embodiments, the inclined complementary liner surface comprises a plurality of protrusions. The plurality of protrusions of the complementary liner surface may be advantageous as they further increase the centrifugal force created by the rotation of the complementary liner. The plurality of protrusions may increase the rotation of slurry or slurry particles present in the channel, which will further increase the effect of material being transported out from behind the impeller.

The plurality of protrusions may for example be shaped as vanes that forces the slurry into rotation in the channel. The plurality of protrusion is arranged such that the slurry with its particles is transported out from the channeL According to some embodiments, the complementary liner is substantially conical. The substantially conical shape of the complementary liner may be advantageous as it is a shape that is easy to produce and easy to install in the centrifugal pump.

According to some embodiments, the inclined complementary liner surface has a curvature. ln some embodiments it may be advantageous with a complementary liner surface having a curvature. ln some examples, the inclined back liner portion may be irregularly shaped and to maintain a substantially constant width of the channel throughout its extension, it may be advantageous that the inclined complementary liner surface follows the irregular shape of the inclined back liner portion. ln other examples, it may be advantageous to provide the channel with a width that varies along the extension of the channel.

According to some embodiments, the back liner comprises a through- hole arranged such to allow a flow therethrough and further through the channel. This may be advantageous in that it allows adding a fresh flow of liquid or air. The through-hole is connected with the first end of the channel and therefore allows a flow through the through-hole and into the channel. Thereby liquid or air may be used to push the slurry with abrasive particles out from the channel and out from the space behind the impeller. This will further increase the efficiency of the forcing of slurry particles through the channel, and thus of the sealing effect of the liner arrangement. The flow may further reduce the wear on the liner arrangement.

According to some embodiments, the inclined complementary liner surface, and the inclined back liner portion each have an inclination angle of between 10° and 85°, such as between 15° and 80°, such as between 20° and 75°, such as between 25° and 70°, such as between 30° and 80°, such as between 10° and 60.

An inclination angle of between 35° and 55° may be advantageous as it provides a smooth transition between the first back liner portion and the second back liner portion. The inclination angle is dependent on the distance between the first back liner portion and the second back liner portion.

According to some embodiments, the channel has a channel width of up to 10 mm, preferably of 0.1-5 mm, more preferably of 0.1-3 mm. The channel width being less than 10 mm may be advantageous as larger particles or material may not be allowed to enter the channel. With a smaller width, less slurry is able to enter the channel and the force required to force the slurry out may be reduced.

The back liner may be made of a high chromium steel or a polymer such as rubber or polyurethane. The back liner may be made of other metals and/or other polymers as well, such as stainless steel, natural rubber, and synthetic rubber. ln other words, the back liner may be made from one or a combination of the group of materials comprising high chromium steel, polyurethane, stainless steel, natural rubber, and synthetic rubber.

The complementary liner may be made of a polymer. lt may be advantageous to have the complementary liner made of a polymer as it is cost-efficient and easy to produce in different shapes and large quantities. However, providing the complementary liner of another material suitable for use in a slurry pump, such as a metal or a composite is also conceivable within the concept of the present disclosure. For example, the complementary liner may be made from one or a combination of the group of materials comprising high chromium steel, polyurethane, Stainless steel, natural rubber, and synthetic rubber.

According to a second aspect, there is provided a centrifugal pump for processing slurries comprising a drive shaft, an impeller, and a liner arrangement according to the first aspect. The back liner of the liner arrangement is arranged around at least the back portion of the impeller of the centrifugal pump and around a circumferential portion of the drive shaft, and wherein the complementary liner of the liner arrangement is arranged at a circumferential end portion of the drive shaft and at a central back portion of the impeller.

According to some embodiments, the complementary liner is releasably arranged at the circumferential end portion of the drive shaft and/or at the central back portion of the impeller.

The releasably arranged complementary liner may be advantageous as it allows and facilitates the process of exchanging the complementary liner of the centrifugal pump when or if needed due to wear of the complementary liner. The complementary liner may for example be attached in a groove or a spline of the drive shaft and/or the central back portion of the impeller. ln an embodiment, the complementary liner is arranged in a threaded engagement with the drive shaft and/or with the central back portion of the impeller.

According to some embodiments, the complementary liner is integral with the circumferential end portion of the drive shaft or with the central back portion of the impeller. This may be advantageous in that it reduces the risk of wear between the complementary liner and the drive shaft or the impeller.

According to some embodiments, the complementary liner is fixedly arranged at the circumferential end portion of the drive shaft or at the central back portion of the impeller. This may be advantageous as it provides a balance between the risk of wear and the possibility of maintenance through replacing the complementary liner. This is further advantageous in that it provides a steadily mounted liner arrangement. ln an embodiment, the complementary liner is fixedly arranged at the drive shaft by welding or by adhesion. ln an embodiment, the complementary liner is fixedly arranged at the central back portion of the impeller by welding or by adhesion.

According to some embodiments, the centrifugal pump further comprises a sealing arranged around the drive shaft immediately adjacent the back liner.

According to some embodiments, a fluid in|et is arranged at a portion of the intersection between the back liner and the sealing such to allow a flow through the in|et and further through the channel.

Effects and features of the second aspect are largely analogous to those described above in connection with the first aspect. Embodiments mentioned in relation to the first aspect are largely compatible with the second aspect. lt is further noted that the inventive concepts relate to all possible combinations of features unless explicitly stated otherwise.

A further scope of applicability of the present disclosure will become apparent from the detailed description given below. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the scope of the disclosure will become apparent to those skilled in the art from this detailed description.

Hence, it is to be understood that this disclosure is not limited to the particular component parts of the device described or steps of the methods described as such device and method may vary. lt is also to be understood that the terminology used herein is for purpose of describing particular embodiments only and is not intended to be limiting. lt must be noted that, as used in the specification and the appended claim, the articles "a", "an", "the", and "said" are intended to mean that there are one or more of the elements unless the context clearly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps. 11 Brief descriptions of the drawinqs The present disclosure will by way of example be described in more detail with reference to the appended drawings, which show example embodiments of the disclosure.

Fig. 1 shows a perspective cross-sectional view of a centrifugal pump known in the prior art.

Fig. 2 shows a perspective cross-sectional view of a portion of a centrifugal pump comprising a liner arrangement according to an embodiment of the present disclosure.

Fig. 3 shows a perspective view of a complementary liner of a liner arrangement according to an embodiment of the present disclosure.

Fig. 4 shows a perspective cross-sectional view of a portion of a centrifugal pump comprising a liner arrangement according to another embodiment of the present disclosure.

Fig. 5 shows a perspective cross-sectional view of a centrifugal pump comprising a liner arrangement according to yet another embodiment of the present disclosure.

Detailed description The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the disclosure are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and to fully convey the scope of the disclosure to the skilled person.

Fig. 1 shows a prior art centrifugal pump 102. ln operation, slurry enters the centrifugal pump 102 through an inlet 150 and flows to a pump chamber 107 comprising an impeller 103. The impeller 103 is supported on a drive shaft 106 which rotates the impeller 103. The rotation of the impeller 12 103 generates a centrifugal force that forces the slurry towards an outlet 140, also commonly referred to as the discharge, where it exits the centrifugal pump 102. The parts of the centrifugal pump 102 are enclosed in a casing 120. To protect the inner wall surfaces of the casing 120 from being worn by the slurry passing thereby, the casing 120 is provided with liner elements. More particularly, in the shown prior art centrifugal pump 102, the casing 120 comprises a back liner 110, a front liner 130, and a peripheral liner 132. ln some embodiments, the drive shaft 106 may have a liner in the form of a sleeve. The back liner 110 extends along inner wall portions of the casing 120 behind the impeller 103, i.e. at the opposite side of the impeller as that of the inlet 150. However, it is not possible to have direct contact between the impeller 103 and the back liner 110 as the wear from the rotational movement of the impeller 103 would be too severe. Therefore, a gap 160 is provided between the impeller 103 and the back liner 110. As previously stated, a challenge with this type of prior art centrifugal pump is that the gap 160 allows slurry to enter a space 162 behind the impeller resulting in undesirable slurry leakage towards the shaft and to problems of build-up of particles in open spaces behind the impeller. To seal the shaft 106 from any leaked slurry, a stuffing box 170 is provided around the shaft 106 adjacent the back liner 110.

Turning to Fig. 2, an embodiment of a liner arrangement 1 according to the present disclosure is shown. More particularly, Fig. 2 illustrates a back portion of a centrifugal pump 2 for processing slurries comprising the liner arrangement 1 according to an embodiment of the present disclosure. The centrifugal pump 2 comprises an impeller 3 and a drive shaft 6 connected with a back portion 4 of the impeller 3. The drive shaft 6 has an axis A around which it rotates. The impeller 3 is enclosed in a casing 9 of the centrifugal pump 2 and is a closed type impeller.

A liner arrangement 1 is configured to protect inner wall surfaces of the casing 9, the impeller 3 and the drive shaft 6 from wear. The liner arrangement 1 may also be configured to provide protection against corrosive wear. The liner arrangement 1 comprises a back liner 10 arranged around the 13 back portion 4 of the impeller 3 and around a circumferential portion 7 of the drive shaft 6. The liner arrangement 1 further comprises a compiementary liner 20 arranged at a circumferential end portion 8 of the drive shaft 6 and at a central back portion 5 of the impeller 3.

The back liner 10 of the liner arrangement 1 comprises a first back liner portion 14, a second back liner portion 16 and an inclined back liner portion 11. The first back liner portion 14 is arranged around a circumferential portion 7 of the drive shaft 6 of the centrifugal pump 2. The second back liner portion 16 is arranged around at least the back portion 4 of the impeller 3 of the centrifugal pump 2, and the inclined back liner portion 11 connects the first back liner portion 14 with the second back liner portion 16. The second back liner portion 16 extends along the axis A of the drive shaft 6. The first back liner portion 14 extends in a direction substantially perpendicular to the axis A. The inclined back liner portion 11 has an inclination angle oi such that it bridges the distance between the first back liner portion 14 and the second back liner portion 16. ln Fig. 2, the inclination angle oi of the inclined back liner portion 11 is around 45°. The inclination angle oi is measured with respect to the axis A. Further, in the shown embodiment, the first back liner portion 14 comprises a sealing 15 that extends from a circumferential portion of the first back liner portion 14 to a circumferential surface portion of the drive shaft 6 such to seal a space therebetween. The sealing 15 may be of a low friction material and can therefore be in contact with the drive shaft 6 to provide full sealing thereof. This allows stopping slurry from travelling along the drive shaft 6, even when the pump is not in operation. The sealing 15 may for example be a type of gland sealing.

The inclined back liner portion 11 provides an inclined back liner surface 12. The inclined back liner surface 12 is in this exemplifying embodiment provided with a groove 13 that extends helically along the inclined back liner surface 12. The groove 13 extends from the connection point with the first back liner portion 14 to the connection point with the second back liner portion 16. The groove 13 is provided with an open end 14 towards the first back liner portion 14 and an open end toward the second back liner portion 16. ln other words, the helical shape of the groove 13directs any material having entered between the back liner 10 and the complementary liner 20 back towards the pump chamber. ln some embodiments, the groove depth is preferably adapted to be able to hold the particles of the slurry. A suitable groove depth may be 1-13 mm. The cross- sectional of the groove may have any shape suitable for the purpose of providing a groove for guiding slurry particles, such as square, conical, oval, or other. The function of the groove 13 will be further described below. Turning to the complementary liner 20 in Fig. 2 and Fig. 3. The complementary liner 20 has a substantially conical shape wherein the wider portion is arranged at the central back portion 5 of the impeller 3 and the narrow top portion is arranged at the circumferential end portion 8 of the drive shaft 6. The complementary liner may be fixedly or releasably connected to the drive shaft 6 and to the impeller 3. ln Fig. 2 the complementary liner 20 is fixedly connected to the drive shaft 6 and to the impeller 3. The complementary liner 20 comprises an inclined complementary liner surface 22 that faces the inclined back liner surface 12. The inclined complementary liner surface 22 has an inclination angle oi that is the same as the inclination angle oi of the inclined back liner portion 11. ln this exemplifying embodiment, the inclination angle oi is around 45°. Providing an inclination angle smaller or larger than 45 ° is however also conceivable within the concept of the present disclosure. A channel 30 is provided between the inclined back liner surface 12 and the inclined complementary liner surface 22. The channel 30 preferably has a channel width W of up to 10 mm, more preferably of up to 5 mm, even more preferably of 0.1-3 mm. The channel width may be adapted to the width between the second back liner portion 16 and the impeller 3 such that one long channel 30 is provided. The complementary liner 20 rotates with the drive shaft 6 and the impeller 3 and thereby sets the slurry in rotation in the channel 30. The centrifugal force that is generated due to the rotation will force any slurry having entered the channel 30 towards the inclined back liner portion 11 wherefrom it will follow the one or more grooves 13 out to the pump chamber. This effect is enhanced by the groove 13 of the inclined back liner surface 12. That is, in operation of the centrifugal pump 2, centrifugal forces will push the slurry into the groove 13 and the rotation will cause the slurry to travel along the groove 13. This effect will be enhanced if the groove 13 is helically shaped, providing a rotational direction towards the pump chamber. The centrifugal force provided by the sealing arrangement 1 during operation of the centrifugal pump 2 with a rotational direction towards the pump chamber further prevents slurry from entering the channel 30 from the pump chamber when the centrifugal pump 2 is in operation.

The complementary liner 20 is further provided with protrusions 24 at the inclined complementary liner surface 22, best seen in Fig. 3. ln this exemplifying embodiment, the protrusions 24 are shaped as paddles or vanes. The protrusions 24 will increase the rotation of the slurry which will further increase the centrifugal force generated when the complementary liner 20 rotates with the drive shaft 6.

With further reference to Fig. 2, the back liner comprises a through- hole 17 arranged such to allow a flow through the through-hole 17 and further through the channel 30. The through-hole 17 may further extend through the casing 9 of the centrifugal pump 2 at a first end and extend to the bottom of the channel 30 at its second end. The through-hole 17 allows a flow of liquid or air to pass therethrough. Such a flow may be pressurised such that it pushes slurry and, particularly, particles of the slurry out from the channel 30. For example, a flow of water may be provided through the through-hole 17, which flow is used to create a flow through the channel 30 towards the pump chamber of the centrifugal pump 2. ln this exemplifying embodiment, the through-hole 17 is arranged to extend through the first back liner portion 14. The through-hole 17 may further be located at either side of the seal 15. ln the embodiment here described with reference to Fig. 2, the seal 15 is located between the through-hole 17 and the channel 30. ln the exemplifying 16 embodiment described in the following with reference to Fig. 4, the through- hole 17 is located between the seal 15 and the channel 30. With a smaller channel width of the channel 30, the flow of water can be reduced.

With reference now to Fig. 4 a liner arrangement 100 and centrifugal pump 2 according to another embodiment of the present disclosure is provided. The liner arrangement 100 has a back liner 10 and a complementary liner 20. The complementary liner 20 is integral with the circumferential end portion 8 of the drive shaft 6. ln other words, the complementary liner 20 is integrally formed with the drive shaft 6 and then arrangeable at the impeller 3. With the complementary liner 20 integrally formed with the drive shaft 6, there will be no joint where wear may occur between these two parts. Further, in this exemplifying embodiment, the back liner 10 comprises the second back liner portion 16 and the inclined back liner portion 11, as described with reference to Fig. 2, but not a first back liner portion as described with reference to Fig. 2. The end 111 of the inclined back liner portion 11 here abuts a sealing 25 arranged around the drive shaft 6. The sealing 25 may be a stuffing box typically used for centrifugal pumps but adapted in size to accommodate the inclined back liner portion 11. A fluid inlet 17 is further provided at a portion of the intersection between the sealing 25 and the back liner 10, which allows a fluid flow, such as a freshwater flow, to be added to flow through the fluid inlet 17 and further through the channel 30.

Turning to Fig. 5 a liner arrangement 200 and centrifugal pump 2 according to yet another embodiment of the present disclosure is shown. ln this embodiment, the liner arrangement 1 comprises a back liner 10 as described with reference to Fig. 2. The complementary liner 20 is here provided with an inclined complementary liner surface 22 that has a curvature. ln some embodiments it may be advantageous with a complementary liner surface 20 having a curvature. ln some examples, the inclined back liner portion 11 may be irregularly shaped and to keep a width of the channel 30 constant, the inclined complementary liner surface 22 may follow the irregular shape of the inclined back liner portion 11. ln other 17 examples, it may be advantageous that the width of the channel 30 is varied along the extension of the channel. Further, in the embodiment shown in Fig. 5, the complementary liner 20 is integral with the central back portion 5 of the impeller 3.

The liner arrangement 200 may be made of different kinds of materials.

For example, the back liner may be made of a high chromium steel or a polymer such as rubber or polyurethane. The complementary liner may be made of a polymer or of a metal. As is understood by the skilled person in view of this disclosure, the material may be adapted to fit the particular conditions in which the sealing arrangement is to operate.

The person skilled in the art realizes that the present disclosure by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

For example, the material may be changed, the shape of the complementary liner and the back liner could be irregular, and the centrifugal pump may be of different sizes or handle different sort of slurries which requires adaptation of the liners.

Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed disclosure, from a study of the drawings, the disclosure, and the appended claims.

Claims (17)

Claims

1. A liner arrangement (1, 100, 200) for a centrifugal pump (2) for processing slurries, the centrifugal pump (2) comprising an impeller (3) and a drive shaft (6) connected with a back portion (4) of the impeller (3), the liner arrangement (1, 100, 200) comprising: a back liner (10) arrangeable around at least the back portion (4) of the impeller (3) of the centrifugal pump (2) and around a circumferential portion (7) of the drive shaft (6), a complementary liner (20) arrangeable at a circumferential end portion (8) of the drive shaft (6) and at a central back portion (5) of the impeller (3), wherein the back liner (10) comprises an inclined back liner portion (11) providing an inclined back liner surface (12) and the complementary liner (20) comprises an inclined complementary liner surface (22), wherein the inclined back liner surface (12) is opposite the inclined complementary liner surface (22), and wherein the liner arrangement (1, 100, 200) is configured to provide a channel (30) between the inclined back liner surface (12) and the inclined complementary liner surface (22).

2. The liner arrangement (1, 200) according to claim 1, wherein the back liner (10) further comprises; a first back liner portion (14) arrangeable around the circumferential portion (7) of the drive shaft (6) of the centrifugal pump (2), a second back liner portion (16) arrangeable around at least the back portion (4) of the impeller (3) of the centrifugal pump (2), and the inclined back liner portion (11) configured to connect the first back liner portion (14) with the second back liner portion (16).

3. The liner arrangement (1, 200) according to claim 2, wherein the first back liner portion (14) comprises a sealing (15) configurable to extend from asurface portion of the first back liner portion (14) to a circumferential surface portion of the drive shaft (6) such to seal a space therebetween.

4. The liner arrangement (1, 100, 200) according to any one of the preceding claims, wherein the inclined back liner surface (12) comprises one or more grooves (13).

5. The liner arrangement (1, 100, 200) according to claim 4, wherein the one or more grooves (13) extend helically along the inclined back liner surface (12).

6. The liner arrangement (1, 100 ,200) according to claim 4 or 5, wherein the one or more grooves (13) have a groove depth of 1-13 mm.

7. The liner arrangement (1, 100, 200) according to any one of the preceding claims, wherein the inclined complementary liner surface (22) comprises a plurality of protrusions (24).

8. The liner arrangement (1) according to any one of the preceding claims, wherein the complementary liner (20) is substantially conical.

9. The liner arrangement (1, 100, 200) according to any one of the preceding claims, wherein the back liner (10) comprises a through-hole (17) arranged such to allow a flow therethrough (17) and further through the channel (30).

10. The liner arrangement (1, 100, 200) according to any one of the preceding claims, wherein the inclined complementary liner surface (22) and the inclined back liner portion (11) each have an inclination angle (oi) of between 10° and 85°, preferably between 20° and 70°, more preferably between 30° and 60°.

11. The liner arrangement (1, 100, 200) according to any one of the preceding claims, wherein the channel (30) has a channel width (W) of up to 10 mm, preferably of up to 5 mm, more preferably of 0.1-3 mm.

12. A centrifugal pump (2) for processing slurries comprising a drive shaft (6), an impe||er (3), and a liner arrangement (1, 100, 200) according to any one of the preceding claims, wherein the back liner (10) of the liner arrangement (1, 100, 200) is arranged around at least the back portion (4) of the impe||er (3) of the centrifugal pump (2) and around a circumferential portion (7) of the drive shaft (6), and wherein the complementary liner (20) of the liner arrangement (1, 100, 200) is arranged at a circumferential end portion (8) of the drive shaft (6) and at a central back portion (5) of the impe||er (3).

13. The centrifugal pump (2) according to claim 12, wherein the complementary liner (20) is releasably arranged at the circumferential end portion (8) of the drive shaft (6) and/or at the central back portion (5) of the impe||er.

14. The centrifugal pump (2) according to claim 12, wherein the complementary liner (20) is integral with the circumferential end portion (8) of the drive shaft (6) or with the central back portion (5) of the impe||er (3).

15. The centrifugal pump (2) according to claim 12, wherein the complementary liner (20) is fixedly arranged at the circumferential end portion (8) of the drive shaft (6) or at the central back portion (5) of the impe||er (3).

16. The centrifugal pump according to any one of claims 12-15, wherein the centrifugal pump (100) further comprises a sealing (25) arranged around the drive shaft (6) immediately adjacent the back liner (1 O).

17. The centrifugal pump according to c|aim 16, wherein a fluid in|et is arranged at a portion of the intersection between the back liner (10) and the sealing (25) such to allow a flow through the in|et and further through the channel (30).