Centrifugal pump having self-cleaning function

Abstract

The invention relates to a centrifugal pump (1) comprising: an impeller (2), which is rotatable about an axis (5), for delivering a fluid; a volute (3) into which the impeller (2) is axially inserted; and an intake strainer (4) into which the volute (3) is axially inserted; wherein the volute (3) has at least one pressure channel (12) leading from the impeller (2) to the intake strainer (4) for receiving a portion of the fluid delivered by the impeller (2), and a deflection device (6) which can be connected to the pressure channel (12) is provided in a radial gap (7) between the volute (3) and the intake strainer (4), by means of which deflection device the portion of the fluid can be deflected in the direction of rotation or counter to the direction of rotation of the impeller (2).

Description

[0001] centrifugal pump

[0002] Technical field

[0003] The invention relates to a centrifugal pump with an impeller rotatable about an axis for pumping a fluid, a centrifugal chamber in which the impeller is axially inserted, and a suction strainer in which the centrifugal chamber is axially inserted.

[0004] Background of the invention

[0005] Centrifugal pumps are known from the prior art and are used to pump a liquid as a fluid by means of the rotary motion of an impeller. The liquid to be pumped enters the pump chamber of the centrifugal pump through a suction port, is captured by the rotating impeller, and subsequently conveyed to a discharge port. Solid particles contained in the liquid can settle in the area of ​​the impeller and on the inside of the pump housing, thus negatively affecting the hydraulic and / or mechanical efficiency of the centrifugal pump or even causing it to become clogged and fail.

[0006] Although various designs for centrifugal pumps for removing deposits are known from the prior art, current practice shows that these designs are not ideal for easily removing deposits, especially those inside the pump. In some cases, the centrifugal pumps even have to be disassembled to remove the deposits.

[0007] Description of the invention

[0008] Starting from this situation, it is an object of the present invention to provide a centrifugal pump which can be easily freed from a deposit, in particular within a radial gap between a centrifugal chamber and a suction strainer of the centrifugal pump.

[0009] The object of the invention is achieved by the features of the independent claim. Advantageous embodiments are specified in the dependent claims.

[0010] Accordingly, the task is solved by a centrifugal pump with an impeller rotatable about an axis for pumping a fluid, a centrifugal chamber in which the impeller is axially inserted, and a suction strainer in which the centrifugal chamber is axially inserted, wherein

[0011] the centrifugal chamber has at least one pressure channel leading from the impeller to the suction strainer for receiving a portion of the fluid conveyed by the impeller, and

[0012] A deflection device, connectable to the pressure channel, is provided in a radial gap between the centrifugal chamber and the suction strainer, by which part of the fluid can be deflected in the direction of rotation or against the direction of rotation of the impeller.

[0013] In other words, the centrifugal pump comprises an impeller that is rotatably mounted around an axis to pump a fluid. This impeller is axially inserted into a centrifugal chamber, which in turn is axially inserted into a suction strainer. The centrifugal chamber has at least one pressure channel that can receive a portion of the fluid pumped by the impeller and direct it towards the suction strainer. A radial gap exists between the centrifugal chamber and the suction strainer, in which a deflector is arranged. This deflector can be connected to the pressure channel and serves to redirect the fluid portion either in the direction of impeller rotation or in the opposite direction.

[0014] A key aspect of the proposed solution is that the deflection device allows for the removal of contamination from the radial gap, for example, if stones, sludge, or sand remain in the radial gap and negatively affect the operation, particularly the adjustment mechanism for moving the centrifugal chamber and suction strainer relative to each other within the centrifugal pump. In other words, the solution provides a kind of self-cleaning function for the radial gap and / or the interior of the suction strainer without requiring disassembly of the centrifugal pump or the suction strainer. For this purpose, the centrifugal chamber and the suction strainer are preferably designed to be rotatable and / or axially displaceable relative to each other, so that the deflection device is exposed to the fluid by rotation and / or displacement.Therefore, the twisting and / or shifting can be understood as acting as a switch to activate the described self-cleaning function for the radial gap. The radial gap preferably extends radially between the centrifugal chamber and the suction strainer and is preferably > 0 mm and < 5 mm, more preferably > 1 mm and < 2, 3, or 4 mm. The deflection preferably occurs tangentially to the centrifugal chamber and / or the suction strainer in the area of ​​or at the deflection device.

[0015] The centrifugal pump with self-cleaning function according to the invention contributes in particular to two United Nations Sustainable Development Goals (SDGs). The centrifugal pump increases resource efficiency and promotes sustainable industrialization (SDG 9) with reduced downtime and maintenance work, and thus also supports the sustainable use of water resources (SDG 12) through more reliable pump operation.

[0016] A centrifugal pump is generally defined as a turbomachine that utilizes rotary motion and dynamic forces to pump predominantly liquids. In addition to the tangential acceleration of the liquid, a centrifugal force occurring in radial flow is used for pumping, which is why such pumps are also referred to as centrifugal pumps. Centrifugal pumps are preferably used in the hydraulic systems of buildings or other applications, particularly as wastewater pumps.

[0017] In normal operation of the centrifugal pump, the motor housing can be arranged above the pump housing, which contains the impeller driven by the motor via a shaft for pumping the fluid, and the centrifugal chamber. The motor housing can be permanently connected to the pump housing and / or be a single unit. The centrifugal pump and the motor can each have their own shaft, which can be connected to each other via a coupling. Preferably, the shaft projects from the motor housing into the pump housing on one drive side and / or is permanently connected to the shaft on the impeller drive side. The suction strainer is designed to be removable from the centrifugal chamber.

[0018] The fluid or liquid preferably comprises water or another liquid medium such as wastewater. The fluid or liquid may also include solids such as contaminants or waste of any kind, in particular feces, sediments, dirt, sand, or even small pieces of wood, brush, textiles, rags, or the like. Preferably, the motor housing and / or the pump housing is made of metal, in particular cast iron or stainless steel, ceramic, and / or plastic.

[0019] The impeller is preferably inserted, at least with its blades, and in particular completely, into the centrifugal chamber. Likewise, the centrifugal chamber is preferably completely insertable into the suction strainer, or the suction strainer can be axially mounted onto the centrifugal chamber such that the suction strainer encompasses the centrifugal chamber, particularly in at least one position, and preferably in all positions, axially and / or radially. Accordingly, an outer shape of the impeller is preferably designed to correspond to an inner shape of the centrifugal chamber, while an outer shape of the centrifugal chamber is preferably designed to correspond to an inner shape of the suction strainer. "Inserted axially" means, in particular, that, in the case of the suction strainer and the centrifugal chamber, the suction strainer and the centrifugal chamber overlap axially, at least partially.Similarly, an intermediate ring could be placed between the suction strainer and the centrifugal chamber, shaped such that the suction strainer and centrifugal chamber do not axially overlap. The suction strainer preferably has a radially extending suction strainer base and an adjoining, axially extending suction strainer side wall that radially surrounds the suction strainer base. The centrifugal chamber can also be described as a spiral.

[0020] According to a preferred embodiment, the centrifugal chamber and the suction strainer are rotatable and / or axially displaceable relative to each other in at least a first and a second position such that the pressure channel is deactivated in the first position and connected to the deflection device in the second position. A type of adjustment mechanism is thus proposed in the form of the centrifugal chamber and suction strainer being rotatable and / or axially displaceable relative to each other, thereby allowing different operating modes of the centrifugal pump, which is particularly suitable as a wastewater pump. While a normal operation of the centrifugal pump preferably takes place in the first position, in which the fluid is drawn in, for example, through a lateral suction opening and / or a bottom suction opening, a so-called flushing operation can be implemented in the second position, in which the pressure channel is particularly connected to the deflection device.This advanced training enables targeted control of fluid deflection by changing the relative positions of the centrifugal chamber and suction strainer. The proposed solution allows for cleaning of the radial gap between the suction strainer and centrifugal chamber, thus ensuring improved adjustability between them. Simultaneously, the suction strainer can be cleaned, thereby also ensuring axial adjustability, for example, for deep suction applications.

[0021] According to a further preferred embodiment, the deflection device is provided and / or formed on and / or in an outer wall of the centrifugal chamber, which extends particularly axially, and / or on and / or in an inner wall of the suction strainer, which extends particularly axially. In this way, the deflection device can be integrated in a space-saving manner and designed for optimal flow characteristics, thereby also enabling functional integration of the deflection device into the existing installation space of the centrifugal pump. Preferably, the deflection device is designed as a flow-guiding element to deflect the fluid portion. By arranging it on axially extending wall sections, the deflection device can be designed to be flow-optimized without increasing the outer housing volume of the centrifugal pump or requiring additional components.By choosing the position, either on the centrifugal chamber or the suction strainer, or both, simple manufacturing and modular adaptability to various pump configurations are enabled. The deflection device can be milled into the outer wall of the centrifugal chamber and / or the inner wall of the suction strainer, injection-molded, and / or produced by joining two or more parts.

[0022] In another preferred embodiment, the deflection device, viewed axially, has a wedge-shaped, teardrop-shaped, and / or kidney-shaped contour and / or bulge, the radial diameter of which decreases in the direction of rotation or against the direction of rotation of the impeller, the shape and / or bulge extending axially. Alternatively or additionally, the deflection device, viewed radially, could also have a wedge-shaped, teardrop-shaped, and / or kidney-shaped contour and / or bulge, particularly with decreasing depth along an axial profile. Such shapes facilitate a directed and low-loss deflection of the fluid portion, widening the flow in particular to achieve effective flushing of the radial gap. Such a geometry redirects the incoming fluid along a defined contour without an abrupt change in direction.The decreasing radial width of the shape, contour, and / or bulge facilitates a transition from an inflowing radial to an outflowing tangential flow component. The axial extension enables continuous deflection across the axial height of the radial gap. The deflection device can thus be integrated into the wall structure of the centrifugal chamber or suction strainer without requiring additional space.

[0023] According to a further preferred embodiment, the deflecting device, viewed axially, has a bulge, a concave surface, and / or a quarter-circle-like structure for deflecting a portion of the fluid in the direction of rotation or against the direction of rotation of the impeller. Furthermore, the deflecting device, viewed axially, allows the portion of the fluid to be deflected, particularly at an approximately right angle, and / or extends axially. This further development aims to deflect the portion of the fluid exiting the pressure channel in a particularly flow-optimized manner, either in the direction of rotation or against the direction of rotation of the impeller.

[0024] This geometry enables a smooth and controlled deflection of the fluid flow, with the quarter-circle contour in particular allowing a defined deflection of approximately 90 degrees. The concave surface acts as a flow guide vane, absorbing the fluid's kinetic energy and transferring it to a new flow direction, either in the direction of rotation or against the impeller's rotation, without causing pronounced turbulence or backflow. Furthermore, the axial extension of the deflection device ensures a continuous deflection along the axial height of the radial gap, guaranteeing a homogeneous distribution of the deflected fluid and thus effective cleaning of the radial gap.In another preferred embodiment, an outer wall of the centrifugal chamber and an inner wall of the suction strainer axially overlap, and the axial extent of the deflection device essentially corresponds to and / or is congruent with the axial overlap. In this way, the radial gap can be cleaned by the fluid component essentially along its entire axial extent.

[0025] According to a further preferred embodiment, the deflection device extends between a beginning and an end, either in the direction of rotation or against the direction of rotation of the impeller, and the deflection of the fluid portion occurs at the beginning. This improved design enables the targeted steering of the fluid portion's flow path immediately after it exits the pressure channel. By defining the introduction and deflection at the beginning of the deflection device, the fluid portion can be controlled and redirected in a new direction, either in the direction of rotation or against the direction of rotation of the impeller, and in particular, into a tangential direction right from the start. The shape, contour, and / or type of the deflection device's bulge can support and stabilize the flow along its path. Guiding the flow over a specific length from beginning to end along a circumferential direction can reduce turbulence and local pressure losses.This design allows for precise adaptation of the deflection device to different operating conditions and supports a flow-efficient design of a deflection path for that part of the fluid.

[0026] In another preferred embodiment, it is proposed that a bulge, extending particularly axially, be provided on an outer wall of the centrifugal chamber in the region of the pressure channel opening to seal the radial gap axially. The bulge, particularly in the form of a radial projection, improves the sealing and deflects the flow in only one direction. In the region of the bulge, the radial width of the radial gap is preferably < 10, 5, 2, 1, or < 0.5 mm. The axially extending bulge acts as a sealing element that closes the radial gap in the axial direction or at least restricts the flow, thereby achieving a flow-effective deflection. This ensures that the fluid conveyed through the pressure channel is deflected in a controlled direction by the deflection device without unintentionally escaping into the radial gap in the other direction.This measure therefore improves the efficiency of the deflection or redirection. The radial gap preferably extends radially between the gyratory chamber and the suction strainer, and particularly axially along an axial overlap of the gyratory chamber and the suction strainer.

[0027] In a preferred embodiment, the pressure channel extends radially through a side wall of the gyratory chamber, which extends particularly axially. Preferably, the pressure channel is arranged axially at the level of a radially extending gyratory chamber floor or directly axially above it in the direction of the impeller. Preferably, a plurality of pressure channels are provided, which are arranged particularly at regular intervals, preferably four pressure channels spaced 90° apart.

[0028] In another preferred embodiment, the suction strainer has at least one bottom-side and at least one side-side suction opening for drawing in the fluid, and at least one bypass line connectable to the pressure channel for flushing the centrifugal pump and / or the suction strainer. Such a bypass line enables bottom-side and side-side cleaning or flushing. Accordingly, the side or bottom-side suction opening for the fluid to be pumped is preferably located at the bottom of the pump housing. The at least one bypass line preferably opens near the bottom to minimize flow energy loss. The at least one bottom-side suction opening is preferably located in the bottom of the suction strainer, and / or the at least one side-side suction opening is preferably located in the side wall of the suction strainer.

[0029] Preferably, at least one lateral intake opening is provided on a radial end face of the suction strainer and / or at least one bottom intake opening is provided on an axial end face of the suction strainer. More preferably, a plurality of bottom and / or lateral intake openings are provided, arranged at regular intervals and / or adjacent to one another. Particularly preferred are four groups of three, four, five, or six lateral intake openings each, wherein, in the case of a centrifugal chamber inserted into the suction strainer, a pressure channel is preferably provided substantially between each group. The at least one lateral intake opening preferably extends orthogonally to the axis with respect to its normal, while the at least one bottom intake opening preferably extends parallel to the axis with respect to its normal.The suction basket side wall preferably extends linearly, in particular essentially linearly and / or slightly curved.

[0030] The at least one lateral intake opening is preferably provided axially at the level of the suction strainer base or directly above it. Where relative terms such as "above" or "below" are used within the scope of this disclosure, these terms refer to the axis in the direction of the impeller or shaft. It is also assumed that the suction strainer, with its underside facing away from the centrifugal chamber, can be placed on a base, so that relative terms such as "below" refer axially to the base. The term "deactivated" means, in particular, closed, partially closed, or covered. The bypass line is preferably arranged partially, and in particular completely, within the suction strainer, especially in the suction strainer side wall. Preferably, the pressure channel can be connected and / or closed, in a fluid-tight manner, by rotating and / or axially displacing the suction strainer and the centrifugal chamber relative to each other.Sealing can be achieved, in particular, by the pressure channel being in contact with the side wall of the suction strainer. Preferably, the suction strainer and the centrifugal chamber are sealed against each other, especially at their edges facing away from the bottom, in a fluid-tight manner, for example by a seal or sealing lip provided, particularly radially, between the suction strainer and the centrifugal chamber. Furthermore, preferably, the centrifugal chamber and / or the suction strainer are provided with a locking device for locking in the respective position, particularly in every position.

[0031] In a preferred embodiment, the centrifugal chamber and the suction strainer are furthermore rotatable and / or axially displaceable relative to each other in at least a third position such that the pressure channel is connected to the at least one bypass line in this third position. In this at least third position, a flushing function can be implemented inside and / or outside the suction strainer, in which fluid first flows in and then partially flows out through the at least one bypass line. Preferably, in the third position, the at least one lateral intake opening is open and / or the at least one pressure channel is connected to the at least one bypass line only in the third position. If the at least one pressure channel and / or the at least one bypass line is deactivated in the first position, no fluid can be backflushed through the pressure channel into a suction strainer area of ​​the centrifugal pump, thus achieving optimal pump performance.Opening the bottom-side suction opening enables optimal flat suction. Finally, when connecting at least one pressure channel to at least one bypass line in the third position, fluid separated for flushing outside the suction strainer can be drawn back in through the side suction opening by opening or leaving the side suction opening open.

[0032] In another preferred embodiment, it is proposed that the rotary chamber has a pot-like outer shape with a particularly circular outer diameter and / or the suction strainer has a pot-like inner shape with a particularly circular inner diameter. Preferably, the rotary chamber and / or the suction strainer are designed to be pot-like, particularly cylindrical.

[0033] According to a preferred embodiment, the suction strainer, particularly in axial plan view, has a polygonal outer shape, and in particular, the at least one bypass line for flushing the centrifugal pump opens at a corner of the polygonal cross-section. Such a polygonal cross-section, designed, for example, as an equilateral rectangle, allows for efficient flushing of the at least one lateral suction opening, since the fluid flow can, and in particular does, flush past all lateral suction openings and thus free the lateral suction openings from contamination or the like.

[0034] Brief description of the drawings

[0035] The invention is explained in more detail below with reference to the accompanying drawings and by way of preferred embodiments.

[0036] In the drawings, Fig. 1 shows a schematic side sectional view of a part of a centrifugal pump with a centrifugal chamber, a suction strainer and an intermediately provided deflection device according to a preferred embodiment of the invention.

[0037] Fig. 2 shows a schematic top-section view of the centrifugal pump of Fig. 1 in a first position of the centrifugal chamber and the suction strainer relative to each other according to the preferred embodiment of the invention.

[0038] Fig. 3 shows a schematic top-section view of the centrifugal pump of Fig. 1 in a second position of the centrifugal chamber and the suction strainer relative to each other according to the preferred embodiment of the invention.

[0039] Fig. 4 shows a schematic top-section view of the centrifugal pump of Fig. 1 in a third position of the centrifugal chamber and the suction strainer relative to each other according to the preferred embodiment of the invention, and

[0040] Fig. 5 is a schematic side section view of a section of Fig. 1 with the deflection device according to the preferred embodiment of the invention.

[0041] Detailed description of the implementation examples

[0042] Fig. 1 shows a schematic side-section view of a portion of a centrifugal pump 1 with a centrifugal chamber 3 and a suction strainer 4 according to a preferred embodiment of the invention. Figs. 2 to 4 each show schematic top-section views of the centrifugal pump 1 of Fig. 1 in a first position, a second position, and a third position of the centrifugal chamber 3 and the suction strainer 4 relative to each other according to the preferred embodiment of the invention. The centrifugal pump 1 has an impeller 2 (only indicated in Figs. 2 to 4) for pumping a fluid, the centrifugal chamber 3, and the suction strainer 4. The impeller 2 defines an axis 5 along which a shaft (not shown in Figs. 2 to 4) extends axially. The shaft is driven by a motor (not shown) so that impeller blades (not shown) can pump the fluid.

[0043] As indicated in the top views of Figures 2 to 4, the centrifugal chamber 3 has a pot-like shape with a circular outer diameter and a circular recess into which the impeller 2 is axially inserted. The recess has a radially extending base with an inner wall 10 extending axially away from it in the direction of the shaft. Four pressure outlets for connection to a cooling jacket (not shown) of the centrifugal pump 1 are recessed into the inner wall at regular intervals. A radially extending, tubular pressure channel 12 is provided axially at the level of the centrifugal chamber base, extending circumferentially around each pressure outlet and immediately in front of the end of the pressure outlet which is axially recessed into the base of the centrifugal chamber.

[0044] The respective pressure channel 12 extends through the inner wall 10 of the centrifugal chamber to an axially extending outer wall 13 of the centrifugal chamber 3 and opens into a nose 14 molded onto the outer wall 13. The molded nose 14, viewed radially from the outer wall 13, has a circular shape with the pressure channel 12 opening centrally within it and extends radially away from the outer wall 13. The four noses 14 are arranged at 90° angles to each other on the outer wall 13 of the centrifugal chamber 3. The pressure channel 12, which thus leads from the impeller 2 to the suction strainer 4, can receive a portion of the fluid conveyed by the impeller 2.

[0045] As also indicated in Figures 2 to 4, the centrifugal chamber 3 is axially inserted into the suction strainer 4. Like the centrifugal chamber 3, the suction strainer 4 has a pot-like shape corresponding to the centrifugal chamber 3, but it can be axially longer than the centrifugal chamber 3, so that the centrifugal chamber 3 can be fully inserted into the suction strainer 4. The suction strainer 4 has a radially extending suction strainer base 15 and an axially extending suction strainer inner wall 16 attached to it, which forms a disc-shaped suction strainer recess for inserting the centrifugal chamber 3 into it.

[0046] Returning to Fig. 1, a plurality of adjacent bottom-side suction openings 19 with a circular cross-section for drawing in the fluid are distributed around the axis 5 in the suction strainer base 15. These openings extend axially through the suction strainer base 16. Corresponding to the plurality of adjacent bottom-side suction openings 19, an opening (not shown) is provided in the centrifugal chamber base 9. Each bottom-side suction opening 19 has the same cross-section.

[0047] Ten lateral suction openings 21 with a square cross-section for drawing in fluid are provided on each side of the suction strainer inner wall 16. Each lateral suction opening 21 has the same cross-section, with the bottom suction opening 19 having a smaller cross-sectional area than the lateral suction opening 21. The ten lateral suction openings 21 are arranged at regular intervals and at the same axial height towards the suction strainer bottom 15 and are supported by an upper suction strainer rim 22 facing the shaft, and extend radially through the suction strainer inner wall 16. Specifically, the lateral suction openings 21 are arranged axially approximately at the level of the suction strainer bottom 15.

[0048] The suction strainer 4 also has four bypass lines 23 that can be connected to the respective pressure channel 12, by means of which the centrifugal pump 1 and the suction strainer 4 can be flushed. Each bypass line 23 begins at the inner wall 16 of the suction strainer and opens outside the suction strainer 4 for flushing the centrifugal pump 1, as will be explained later.

[0049] The centrifugal chamber 3 and the suction strainer 4 are in at least the first position, shown in Fig. 2, the second position, shown in Fig. 3, and the third position, shown in Fig.

[0050] 4, rotatable relative to each other. In the first position 31, which is occupied during normal operation of the centrifugal pump 1, the pressure channel 12 is closed and both the lateral and bottom suction openings 19, 21 are open. As can be seen in Fig. 2, the pressure channel 12, with its nose 14, rests almost touching the inner wall 16 of the suction strainer and is closed by it. In the second position, shown in Fig. 3, the pressure channel 12 is connected to a deflecting device 6, which is provided in a radial gap 7 between the centrifugal chamber 3 and the suction strainer 4. The deflecting device 6 is formed on the inner wall 16 of the suction strainer 4 and is shown in detail in Fig. 5 and also in Fig. 1. The deflecting device 6 allows the portion of the fluid to be deflected in the direction of rotation or against the direction of rotation of the impeller 2 into the radial gap 8 for flushing it out.

[0051] The deflection device 6 has a wedge-shaped form in axial plan view, the radial diameter of which decreases in the direction of rotation or against the direction of rotation of the impeller 2. As can be seen in Fig. 1, the outer wall 13 of the centrifugal chamber 3 and the inner wall 16 of the suction strainer 4 overlap axially. An axial extension of the deflection device 6 essentially corresponds to this axial overlap and is arranged congruently to it. The deflection device 6 extends in the direction of rotation or against the direction of rotation of the impeller 2 between a beginning and an end, with the deflection of the portion of the fluid occurring at the beginning. At this beginning, the deflection device 6 has a quarter-circle-shaped, axially extending form in axial plan view, which deflects the portion of the fluid flowing from the pressure channel 12 onto the deflection device 6 at an approximately right angle.

[0052] In the region of the outlet of the pressure channel 12, an axially extending bulge 8 is provided, which encloses the nose 14 and extends over the axial height of the deflecting device 6. The bulge 8 seals the radial gap 7 at the beginning of the deflecting device 6, so that the portion of the fluid is deflected, in principle, completely in the direction of rotation or against the direction of rotation of the impeller 2.

[0053] Fig. 4 shows the centrifugal chamber 3 and the suction strainer 4 rotated relative to each other in the third position, in which the pressure channel 12 is fluid-tightly connected to the at least one bypass line 23. In plan view, the suction strainer 4 has a polygonal, namely quadrilateral, outer shape, and the at least one bypass line 23 opens, as indicated in Fig. 1, at a corner of the polygonal cross-section to flush an outer surface of the suction strainer 4 of the centrifugal pump 1. The described embodiments are merely examples that can be modified and / or supplemented in various ways within the scope of the claims. Each feature described for a particular embodiment can be used independently or in combination with other features in any other embodiment.Each feature described for an embodiment of a particular category can also be used analogously in an embodiment of another category. Reference numeral list.

[0054] Centrifugal pump 1 Impeller 2 Centrifugal chamber 3 Suction strainer 4 Shaft 5 Deflection device 6 Radial gap 7 Bulge 8 Centrifugal chamber inner wall 10 Pressure channel 12 Centrifugal chamber outer wall 13 Nose 14 Suction strainer bottom 15 Suction strainer inner wall 16 Bottom-side suction opening 19 Side-side suction opening 21 Suction strainer rim 22 Bypass line 23

Claims

Patent claims 1. Centrifugal pump (1) with an impeller (2) rotatable about an axis (5) for pumping a fluid, a centrifugal chamber (3) in which the impeller (2) is axially inserted, and a suction strainer (4) in which the centrifugal chamber (3) is axially inserted, wherein the centrifugal chamber (3) has at least one pressure channel (12) leading from the impeller (2) to the suction strainer (4) for receiving a portion of the fluid conveyed by the impeller (2), and In a radial gap (7) between the centrifugal chamber (3) and the suction strainer (4) a deflecting device (6) which can be connected to the pressure channel (12) is provided, by which the part of the fluid can be deflected in the direction of rotation or against the direction of rotation of the impeller (2).

2. Centrifugal pump (1) according to the preceding claim, wherein the centrifugal chamber (3) and the suction strainer (4) are rotatable and / or axially displaceable relative to each other in at least a first and a second position such that the pressure channel (12) is deactivated in the first position (31) and the pressure channel (12) is connected to the deflecting device (6) in the second position (32).

3. Centrifugal pump (1) according to one of the preceding claims, wherein the deflection device (6) is provided and / or formed on and / or in an outer wall (13) of the centrifugal chamber (3) which extends in particular axially and / or on and / or in an inner wall (16) of the suction strainer (4) which extends in particular axially.

4. Centrifugal pump (1) according to one of the preceding claims, wherein the deflection device (6) has a wedge-shaped, droplet-shaped and / or kidney-shaped form and / or bulge in axial plan view, the radial diameter of which decreases in the direction of rotation or against the direction of rotation of the impeller (2), wherein the form and / or bulge extends in particular axially.

5. Centrifugal pump (1) according to one of the preceding claims, wherein the deflection device (6), in axial plan view, has a bulge, a concave surface and / or a quarter-circle-like structure for deflecting the portion of the fluid in the direction of rotation or opposite the direction of rotation of the impeller (2), by means of the deflection device (6), in axial plan view, the portion of the fluid can be deflected in particular at an approximately right angle and / or the deflection device (6) extends axially.

6. Centrifugal pump (1) according to one of the preceding claims, wherein an outer wall (13) of the centrifugal chamber (3) and an inner wall (16) of the suction strainer (4) overlap axially and an axial extension of the deflection device (6) substantially corresponds to the axial overlap and / or is arranged congruently to the axial overlap.

7. Centrifugal pump (1) according to one of the preceding claims, wherein the deflection device (6) extends in the direction of rotation or against the direction of rotation of the impeller (2) between a beginning and an end and the deflection of the part of the fluid takes place at the beginning.

8. Centrifugal pump (1) according to one of the preceding claims, wherein a bulge (8) extending in particular axially is provided on an outer wall (13) of the centrifugal chamber (3) in the area of ​​an opening of the pressure channel (12) in order to seal the radial gap (7) axially.

9. Centrifugal pump (1) according to one of the preceding claims, wherein the pressure channel (12) extends radially through a side wall of the centrifugal chamber (3).

10. Centrifugal pump (1) according to one of the preceding claims, wherein the suction strainer (4) has at least one bottom-side and at least one side suction opening (19, 21) for drawing in the fluid and at least one bypass line (23) connectable to the pressure channel (12) for flushing the centrifugal pump (1) and / or the suction strainer (4).

11. Centrifugal pump (1) according to the preceding claim and claim 2, wherein the centrifugal chamber (3) and the suction strainer (4) are furthermore rotatable and / or axially displaceable relative to each other in at least a third position such that the pressure channel (12) is connected to the at least one bypass line (23) in the third position.

12. Centrifugal pump (1) according to any one of the preceding claims, wherein the centrifugal chamber (3) has a pot-like outer shape with a particularly circular outer diameter and / or the suction strainer (4) has a pot-like inner shape with a particularly circular inner diameter.

13. Centrifugal pump (1) according to one of the preceding claims, wherein the suction strainer (4), in particular in axial plan view, has a polygonal outer shape and in particular the at least one bypass line (23) according to claim 10 for flushing the centrifugal pump (1) opens at a corner of the polygonal cross-section.

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