Centrifugal pump

Abstract

The invention relates to a centrifugal pump (1) with an impeller (2) defining an axis (5) for pumping a fluid, a centrifugal chamber (3) in which the impeller (2) is axially arranged, and a suction strainer (4) having a polygonal cross-section in which the centrifugal chamber (3) is axially arranged, wherein the suction strainer (4) has at least one lateral suction opening (21) provided on a suction strainer side wall (37) of the suction strainer (4) for drawing in the fluid and at least one bypass line (23) that can be supplied with a portion of the fluid pumped by the impeller (2) for flushing the centrifugal pump (1), and the at least one bypass line (23) opens in the direction of the suction strainer side wall (37) in such a way that a fluid flow exiting the at least one bypass line (23) flushes along the suction strainer side wall (37).

Description

Technical field

[0001] The invention relates to a centrifugal pump with an impeller defining an axis for conveying a fluid, a centrifugal chamber in which the impeller is axially arranged, and a suction strainer in which the centrifugal chamber is axially arranged, wherein the suction strainer has at least one lateral suction opening provided on a suction strainer side wall of the suction strainer for drawing in the fluid. Background of the invention

[0002] 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.

[0003] Although different designs of centrifugal pumps for removing deposits from the centrifugal pump are known from the prior art, current practice shows that the known designs are not ideal for easily removing deposits, especially those on the outside of the centrifugal pump. Description of the invention

[0004] Starting from this situation, it is an object of the present invention to provide a centrifugal pump which can be easily cleaned of deposits, in particular outside the centrifugal pump.

[0005] The object of the invention is achieved by the features of the independent claim. Advantageous embodiments are specified in the dependent claims.

[0006] Accordingly, the problem is solved by a centrifugal pump with an impeller defining an axis for pumping a fluid, a centrifugal chamber in which the impeller is axially arranged, in particular inserted, and a suction strainer having a polygonal cross-section in which the centrifugal chamber is axially arranged, in particular inserted, wherein The suction strainer has at least one lateral suction opening provided on a suction strainer side wall for drawing in the fluid and at least one bypass line that can be supplied with a portion of the fluid conveyed by the impeller for flushing the centrifugal pump, and the at least one bypass line opens in the direction of the suction strainer side wall in such a way that a fluid flow exiting the at least one bypass line flushes along the suction strainer side wall.

[0007] A key aspect of the invention is that the suction strainer can be efficiently flushed free of impurities or contaminants by the fluid flow flushing along its side wall. "Flushing along the side wall of the suction strainer" means, in particular, that the fluid flow flows parallel or substantially parallel and / or tangentially to the side wall of the suction strainer, that the fluid flow is oriented, in particular, orthogonally to the at least one lateral intake opening, parallel or substantially parallel to a normal to the at least one lateral intake opening, and / or, in particular, that the fluid flow flows past all lateral intake openings in an orthogonal orientation. Similarly, "oriented towards the side wall of the suction strainer" means, in particular, orthogonally to an outlet opening of the at least one bypass line.At least one bypass line preferably terminates near the bottom to minimize flow energy loss. The suction strainer side wall preferably extends linearly, in particular essentially linearly and / or slightly curved.

[0008] The proposed solution allows not only a limited area and / or a portion of the lateral intake openings to be flushed, as is known from the prior art, but all lateral intake openings of the corresponding suction strainer side wall to be flushed. This enables the suction strainer and its lateral intake openings to be cleaned of contaminants or debris much more efficiently. Since the fluid flow runs along the suction strainer side wall, particularly the outer side wall, the flow, especially in the case of a rectangular suction strainer, can be aligned parallel to the corresponding side wall of the strainer, which preferably extends linearly or nearly linearly on the outside, so that an area in front of the lateral intake openings can be completely flushed.The proposed centrifugal pump thus provides a simple yet highly efficient solution for implementing a so-called 'twister' function, which allows not only one but all lateral suction openings to be flushed free, for example in the case of a deposit on the centrifugal pump, especially in the area of ​​the suction strainer.

[0009] 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, especially as wastewater pumps.

[0010] 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. Likewise, 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 drive side of the impeller. Accordingly, the suction opening for the fluid to be pumped is preferably located at the bottom of the pump housing. The suction strainer is designed to be removable from the centrifugal chamber.

[0011] The fluid preferably comprises water or another liquid medium such as wastewater. The fluid may also include solids such as dirt, impurities, or waste of any kind, in particular feces, sediment, 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.

[0012] The impeller is preferably arranged, at least with its blades, and in particular completely, within the impeller chamber. Likewise, the impeller chamber is preferably fully insertable into the suction strainer, or the suction strainer can be axially mounted onto the impeller chamber such that the suction strainer encompasses the impeller chamber axially and / or radially. Accordingly, an outer shape of the impeller is preferably designed to correspond to an inner shape of the impeller chamber, while an outer shape of the impeller chamber is preferably designed to correspond to an inner shape of the suction strainer.

[0013] The suction strainer preferably has a radially extending suction strainer base and the adjoining, axially extending suction strainer side wall, which radially surrounds the suction strainer base. Accordingly, the at least one lateral suction opening is preferably provided in the suction strainer side wall, also called the radial end face. More preferably, a plurality of lateral suction 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 suction openings each.

[0014] The at least one lateral intake opening is preferably located axially at the level of the suction strainer base or directly above it, but more preferably axially above an outlet opening of the at least one bypass line. 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 bypass line is preferably arranged partially, and in particular completely, within the suction strainer, especially in the suction strainer side wall. In this respect, the suction strainer side wall can preferably be an outer wall of the suction strainer.

[0015] In a preferred embodiment, the outlet opening of the at least one bypass line is arranged substantially orthogonally with respect to its normal, or at an angle of ≥ 70°, ≥ 80°, or ≥ 90° and ≤ 110°, particularly at an angle of 100°, to the suction strainer side wall, and / or is designed to be adjustable with respect to this angle. Preferably, the outlet opening extends substantially orthogonally or at an angle of ≥ 70°, ≥ 80°, or ≥ 90° and ≤ 110°, particularly at an angle of 100°, to the at least one lateral intake opening, and in particular to all lateral intake openings. The lateral intake openings are preferably arranged in a row, particularly linearly. Accordingly, the suction strainer side wall preferably extends linearly, particularly in the case of a suction strainer with a polygonal, rectangular, or square cross-section.Because the outlet opening is preferably oriented slightly away from the side wall of the suction strainer, the fluid flow, even if there are lateral intake openings located further away from the outlet opening, still flows past them without being drawn back into the suction strainer by these lateral intake openings. Preferably, the outlet opening is funnel-shaped.

[0016] According to a further preferred embodiment, an outlet opening of the at least one bypass line is oriented substantially axially, particularly with respect to its normal, or at an angle ≥ 0° and ≤ 20°, particularly 10°, away from the axis of the impeller. Accordingly, if the centrifugal pump is placed on the ground with the suction strainer facing forward, the outlet opening is slightly inclined towards the ground.

[0017] According to another preferred embodiment, the at least one bypass line opens axially below the at least one lateral intake opening with respect to the impeller, in particular such that the fluid flow exiting the at least one bypass line flows below the at least one lateral intake opening. With lateral intake openings arranged axially above the outlet opening with respect to the ground, the fluid flow can flow past the lateral intake openings without being drawn back into the suction strainer by the lateral intake openings.

[0018] According to another preferred embodiment, the suction strainer has a polygonal cross-section, the at least one bypass line opens at a corner of the suction strainer, and, in particular, an outlet opening of the at least one bypass line is oriented towards an opposite corner. Such a polygonal cross-section, designed, for example, as an equilateral rectangle, allows for efficient flushing, since the fluid flow can, and does, flush past, in particular, all the lateral intake openings arranged one behind the other, thus clearing the lateral intake openings of contamination or the like.

[0019] According to a further preferred embodiment, the at least one bypass line opens in such a way as to be oriented towards the suction strainer side wall, which is preferably linear, linear-like or slightly curved on the outside, that the fluid flow flows parallel to the suction strainer side wall along it. If the suction strainer side wall preferably extends linearly, the outlet opening is preferably oriented substantially orthogonal or perpendicular to the suction strainer side wall, as described above.

[0020] According to a further preferred embodiment, the at least one bypass line has a rectangular outlet opening for the fluid flow to exit, the longitudinal sides of which are particularly perpendicular to the axis. The outlet opening can also be square or round.

[0021] According to another preferred embodiment, the at least one bypass line has a bend, particularly upstream of its outlet opening, such that the fluid flow exiting the at least one bypass line is subjected to a swirl along the suction strainer side wall. Such a bend allows the direction of the exiting fluid flow to be influenced, or in particular, deflected vertically and / or horizontally. The direction is preferably influenced by the bend such that the fluid flow, or its direction, extends substantially parallel to the suction strainer side wall.

[0022] According to a further preferred embodiment, the suction strainer has a rectangular and in particular square cross-section with four suction strainer side walls, in particular extending essentially or at least partially linearly, and four bypass lines such that the fluid flows exiting the bypass lines flush along the four side walls.

[0023] According to another preferred embodiment, the four bypass lines terminate at respective corners, or two bypass lines terminate at a common corner, oriented in opposite directions. If the four bypass lines terminate at respective corners, the outlet openings of all bypass lines are preferably oriented in the same direction of circulation. If two bypass lines terminate at a common corner, the outlet openings of the two bypass lines are preferably oriented at an angle of substantially 90°. If two outlet openings oriented in this way are provided at a corner, the two outlet openings can also be supplied by a common bypass line.

[0024] According to a further preferred embodiment, the suction strainer has a plurality of lateral suction openings, in particular arranged at regular intervals and / or at the same axial height, the at least one lateral suction opening has a rectangular, in particular square, cross-section and / or several spaced-apart groups of at least one lateral suction opening are provided.

[0025] According to another preferred embodiment, the centrifugal chamber has at least one pressure outlet leading from the impeller to the suction strainer for receiving the portion of the fluid pumped by the impeller, the at least one bypass line is connectable to the at least one pressure outlet for flushing the centrifugal pump and / or the suction strainer, and the centrifugal chamber and the suction strainer are rotatable and / or axially displaceable relative to each other in at least a first, a second, and a third position such that at least in the first position the at least one lateral intake opening is open, in the second position the at least one lateral intake opening is deactivated, and in the third position the at least one pressure outlet is connected to the at least one bypass line. The term "deactivated" means, in particular, closed, partially closed, or blocked.

[0026] Such an adjustment mechanism, in the form of a centrifugal chamber and suction strainer that are rotatable and / or axially displaceable relative to each other, allows for different operating modes of the centrifugal pump, particularly when designed as a wastewater pump. While the first position preferably represents normal operation of the centrifugal pump, in which fluid is drawn in, in particular, through the at least one lateral suction opening and preferably also through the at least one bottom suction opening, the second position enables so-called flat suction, in which the at least one lateral suction opening is deactivated and fluid is drawn in, in particular, only through the at least one bottom suction opening. Finally, in the at least third position, a flushing function can be implemented inside and / or outside the suction strainer, as already described above.The at least one lateral intake opening preferably extends orthogonally to the axis with respect to its normal, while the at least one bottom-side intake opening preferably extends parallel to the axis with respect to its normal.

[0027] The proposed centrifugal pump is characterized by a variety of operating modes, which can be easily adjusted as needed, either manually or by rotating and / or shifting the centrifugal chamber and suction strainer relative to each other. These different operating modes can be changed without complex manual modifications to the pump or the use of tools. Furthermore, different operating modes are available for flushing the centrifugal pump, both internally and externally, which allows for the rapid removal of deposits, particularly those located outside the pump.

[0028] The pressure outlet preferably extends radially through an axially extending side wall of the centrifugal chamber. More preferably, the pressure outlet is arranged axially at the level of a radially extending bottom of the centrifugal chamber or directly axially above it. Preferably, multiple pressure outlets are provided, arranged particularly at regular intervals, preferably at 90° intervals. Preferably, the pressure outlet can be connected and / or sealed to the bypass line, particularly in a fluid-tight manner, by rotating and / or axially displacing the suction strainer and the centrifugal chamber relative to each other.

[0029] Sealing can be achieved, in particular, by ensuring that the pressure outlet is 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.

[0030] According to a further preferred embodiment, in the first position and in the second position the at least one pressure outlet and / or the at least one bypass line is deactivated, the suction strainer has at least one bottom-side suction opening for drawing in the fluid and in the second position only the bottom-side suction opening is open, in the third position the at least one side suction opening is open and / or only in the third position the at least one pressure outlet is connected to the at least one bypass line.

[0031] Provided that at least one pressure outlet and / or at least one bypass line is deactivated in the first and / or second position, no fluid can be backflushed through the pressure outlet, thus ensuring optimal pump performance. Opening the bottom suction opening only in the second position enables optimal shallow suction. Finally, when connecting at least one pressure outlet to at least one bypass line in the third position, fluid that has been 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.Preferably, the at least one bottom intake opening has a smaller cross-sectional area than the at least one side intake opening, the at least one bottom intake opening has a circular cross-section and / or the at least one side intake opening has a rectangular, in particular square, cross-section.

[0032] According to another preferred embodiment, the at least one bypass line has at least a first and a second bypass line, each connectable to the at least one pressure outlet. The at least one first bypass line opens outside the suction strainer for flushing the centrifugal pump. In particular, the at least one pressure outlet is connected to the at least one first bypass line only in the third position. The at least one second bypass line opens into the suction strainer for flushing the suction strainer. In particular, the at least one pressure outlet is connected to the at least one second bypass line only in a fourth position. The at least one first bypass line and the at least one second bypass line preferably each have an inlet opening, which is recessed into an inner wall of the suction strainer at a circumferential distance from each other.Preferably, the inlet openings are axially mounted above the at least one lateral intake opening. Particularly preferably, four bypass lines or four first bypass lines and four second bypass lines are provided, with the inlet openings of the bypass lines preferably arranged between two groups of lateral intake openings.

[0033] According to a further preferred embodiment, the suction strainer can be removed axially from the centrifugal chamber in a fifth position. Removing the suction strainer allows for easy maintenance and / or cleaning.

[0034] According to another preferred embodiment, the centrifugal chamber and the suction strainer are axially displaceable between the first and second positions and rotatable relative to each other between the first and third positions. Preferably, in the second position, and especially only in the second position, the centrifugal chamber rests in contact with the suction strainer, particularly with the suction strainer base, such that the side wall of the centrifugal chamber closes the at least one lateral intake opening. In all other positions, especially in the first, third, fourth, and / or fifth positions, the base of the centrifugal chamber is preferably arranged differently from the base of the suction strainer, so that the at least one lateral intake opening is not deactivated by the centrifugal chamber.

[0035] According to a further preferred embodiment, the suction strainer has at least one guide track and the centrifugal chamber has at least one guide lug engaging in the at least one guide track for rotating and / or displacing the centrifugal chamber and the suction strainer relative to each other. Preferably, four guide lugs are provided, extending radially away from the side wall of the centrifugal chamber. Correspondingly, four guide tracks are preferably also provided, arranged at regular intervals and / or corresponding to the guide lugs. The at least one guide track preferably extends radially into an inner wall of the centrifugal chamber. The at least one guide track is preferably groove-shaped and / or allows a positive-locking connection of the suction strainer to the centrifugal chamber.

[0036] The at least one guide track preferably extends axially to connect the rotary chamber with the suction strainer or the suction strainer with the rotary chamber in the fifth position, and then bends orthogonally in an L-shape, continuing at the same axial height, particularly when viewed from above the inner wall of the rotary chamber. Preferably, the fifth position, the first position, the third position, and / or the fourth position are located at this same axial height. From this same axial height, the at least one guide track preferably bends again orthogonally, extending further axially towards the bottom of the suction strainer, to form the second position. This bend can be T-shaped in plan view, followed by another L-shaped bend in plan view, within which the second position can be formed at the same axial height.

[0037] According to another preferred embodiment, the at least one pressure outlet opens into the at least one guide nose and directs the at least one bypass line away from the at least one guide track. Preferably, the guide nose, viewed radially from above the gyratory chamber, has a cuboid shape into which the at least one pressure outlet, which in particular has a circular diameter, is inserted. The inlet opening of the bypass line, which is preferably circular, is preferably inserted into an axially extending base of the guide track, and the bypass line leads away from this inlet opening.

[0038] According to a further preferred embodiment, the rotary chamber and the suction strainer are designed to be lockable relative to each other in at least the first, second, and third, and in particular the fourth, position. For the aforementioned locking and / or latching, a locking lug or the like can be provided, which, for example, is arranged to project radially outwards from the guide lug and can engage in a corresponding recess in the guide track provided at the respective position.

[0039] According to another preferred embodiment, the bottom of the suction strainer, located externally to the centrifugal chamber, has at least one feed channel extending radially towards the at least one intake opening on the bottom side. Fluid can flow through the feed channel, which is particularly shaped like a wedge, towards the at least one intake opening on the bottom side. For this purpose, the feed channel is particularly open towards the bottom and is bounded on one side by the suction strainer and laterally by feet provided on the suction strainer. The feet can have a cuboid shape extending radially. Advantageously, the axial height of the feet is less than the axial height of the at least one lateral intake opening.

[0040] According to another preferred embodiment, the centrifugal 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.

[0041] According to a further preferred embodiment, the centrifugal chamber has at least one main pressure outlet for receiving a large portion of the fluid pumped by the impeller, and the at least one pressure outlet is arranged in the vicinity of the at least one main pressure outlet. The at least one main pressure outlet is fluidically connected, in particular, to a cooling jacket of the centrifugal pump. Preferably, the pressure outlet is arranged immediately upstream of the main pressure outlet when viewed in the direction of rotation. More preferably, the pressure outlet is designed as a tubular, radially extending channel. Brief description of the drawings

[0042] The invention is explained in more detail below with reference to the accompanying drawings and by way of preferred embodiments.

[0043] The drawings show Fig. 1 a schematic perspective partial sectional view of a part of a centrifugal pump with a centrifugal chamber in which a partially shown impeller is axially arranged, and a suction strainer in which the centrifugal chamber is axially arranged, according to a preferred embodiment of the invention, Fig. 2 a perspective view of the centrifugal chamber of the Fig. 1 According to the preferred embodiment of the invention, Fig. 3 shows a perspective view of the suction basket of the Fig. 1 According to the preferred embodiment of the invention, Fig. 4 shows a top view of a guide track of the suction strainer. Fig. 1According to the preferred embodiment of the invention, Fig. 5 shows a first position of a guide nose on the guide track, shown above in axial sectional view and below in axial top view. Fig. 4 According to the preferred embodiment of the invention, Fig. 6 shows a third position of the guide nose on the guide track, shown above in axial sectional view and below in axial top view. Fig. 4 According to the preferred embodiment of the invention, Fig. 7 shows a fourth position of the guide nose on the guide track, shown above in axial sectional view and below in axial top view. Fig. 4 According to the preferred embodiment of the invention, Fig. 8 in axial sectional view, a second position of the guide nose on the guide track of the Fig. 4 according to the preferred embodiment of the invention, and Fig. 9 a perspective partial underside view of the suction basket of the Fig. 1 according to the preferred embodiment of the invention. Detailed description of the implementation examples

[0044] Fig. 1 Figure 1 shows a schematic perspective partial sectional view of a part of a centrifugal pump 1, shown only schematically, according to a preferred embodiment of the invention. The centrifugal pump 1 has a Fig. 1 The impeller 2, shown only partially, conveys a fluid, a centrifugal chamber 3, and a suction strainer 4. The impeller 2 defines an axis 5 along which a [missing information] extends axially. Fig. 1 The shaft (not shown) extends. The shaft is driven by a motor (not shown) so that the blades 6 of the impeller 2 can convey the fluid.

[0045] As from Fig. 2 As can be seen in detail, the gyratory chamber 3 has a pot-like shape with a circular outer diameter and a circular gyratory chamber recess 7, into which, as in Fig. 1As shown, the impeller 2 is axially arranged. For this purpose, the impeller 2 has a disc-like plate 8 extending around the axis 5 at its end facing the gyratory chamber 3, as shown in Fig. 8 The shaft (not shown) extends away from plate 8 and the gyratory chamber 3 along axis 5. The blades 6, which are integrally formed with plate 8, extend axially away from plate 8 towards the gyratory chamber 3. Plate 8 extends radially, and the blades 6 extend axially and radially, to the immediate vicinity of the gyratory chamber 3. The gyratory chamber recess 7 thus corresponds to an outer shape of the impeller 2.

[0046] Furthermore, how from Fig. 2 As can be seen, the gyratory chamber recess 7 has a radially extending gyratory chamber floor 9 with a gyratory chamber inner wall 10 extending axially away from it in the direction of the shaft, which forms the Fig. 1The impeller 2, arranged in the centrifugal chamber 3, is axially and radially limited. Four ramp-like main pressure outlets 11 for connection to a cooling jacket (not shown) of the centrifugal pump are embedded at regular intervals in the inner wall 10 of the centrifugal chamber. One end of each ramp-like main pressure outlet 11 is axially embedded in the bottom of the centrifugal chamber 9, while the other end extends axially away from the bottom of the centrifugal chamber 9 towards the shaft. The inner wall of the centrifugal chamber 10 tapers continuously around each ramp-like main pressure outlet 11 until it reaches the respective outlet 11, before projecting radially again towards axis 5 after the outlet 11 or ramp.

[0047] A tubular, radially extending pressure outlet 12 is provided axially at the level of the gyratory chamber floor 9, preceding the ramp-like main pressure outlet 11 and immediately in front of the end of the main pressure outlet 11 which is axially embedded in the gyratory chamber floor 9. Each pressure outlet 12 extends through the inner wall 10 of the gyratory chamber to an axially extending outer wall 13 of the gyratory chamber 3 and opens into a guide lug 14 molded onto the outer wall 13 of the gyratory chamber.

[0048] The molded guide lug 14, viewed radially from above the centrifugal chamber 3, has a cuboid shape with the pressure outlet 12 opening centrally within it and extends radially away from the outer wall 13 of the centrifugal chamber. The four guide lugs 14 are each positioned at 90° to each other on the outer wall 13 of the centrifugal chamber 3. The pressure outlet 12, which leads from the impeller 2 to the suction strainer 4, receives a portion of the fluid conveyed by the impeller 2 during fluid delivery.

[0049] Furthermore, how from Fig. 1 The gyratory chamber 3 can be seen axially in the details in Fig. 3The suction strainer 4 is arranged as shown. Like the centrifugal chamber 3, the suction strainer 4 has a pot-shaped inner form corresponding to the centrifugal chamber 3, but it is 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 17 for inserting the centrifugal chamber 3 into it.

[0050] Returning to Fig. 3A plurality of adjacent axial intake openings 19 with a circular cross-section for drawing in the fluid are distributed around the axis 5 in the suction strainer base 15 and extend axially through the suction strainer base 16. Corresponding to the plurality of adjacent axial intake openings 19, an opening 20 is provided in the centrifugal chamber base 9. Each intake opening 19 on the base has the same cross-section.

[0051] The inner wall 16 of the suction strainer has four groups of five lateral intake openings 21, each with a square cross-section, for drawing in the fluid. Each lateral intake opening 21 has the same cross-section, with the bottom intake opening 19 having a smaller cross-sectional area than the lateral intake opening 21. The five lateral intake openings 21 are arranged at regular intervals and at the same axial height towards the suction strainer base 15 and are supported by an upper suction strainer rim 22 facing the shaft. They extend radially through the inner wall 16 of the suction strainer. Specifically, the lateral intake openings 21 are arranged axially approximately at the level of the suction strainer base 15. A guide track 18 is provided essentially between each group of five lateral intake openings 21.

[0052] The suction strainer 4 also has four groups of two first and second bypass lines 23, 24, each connectable to the respective pressure outlet 12, by means of which the centrifugal pump 1 and the suction strainer 4 can be flushed. Both the first and the second bypass lines 23, 24 originate at the guide track 18, with the first bypass line 23 opening outside the suction strainer 4 for flushing the centrifugal pump 1 and the second bypass line 24 opening inside the suction strainer 4 for flushing the suction strainer 4 itself. Both the first and the second bypass lines 23, 24 have respective inlet openings 25, 26, which are arranged in the base of the groove-like guide track 18. The two inlet openings 25, 26 are at the same axial height but spaced apart from each other and are located axially above the lateral suction openings 21 with respect to the suction strainer base 15.

[0053] An outlet opening 27 of the first bypass line 23 is axially aligned with the corresponding inlet opening 25 of the first bypass line 23 at the level of the suction strainer base 15 and thus axially below the lateral intake openings 21. The suction strainer 4 has a cuboid-shaped projection 28 in radial plan view, which extends radially away from the suction strainer 4 and axially between the suction strainer base 15 and the suction strainer rim 22, within which the first bypass line 23 is arranged and extends axially between the inlet opening 25 and the outlet opening 27. As can be seen from Fig. 3As can be seen, the outlet opening 27 of the first bypass line 23 is assigned to the group of five lateral intake openings 21 and is arranged in a circumferential extension next to the group such that the outlet opening 27 of the first bypass line 23 is oriented essentially orthogonally to the outermost lateral intake opening 21. The inlet opening 25 of the first bypass line 23 has a circular cross-section and the outlet opening 27 of the first bypass line 23 has a rectangular cross-section, the long side of which is oriented parallel to the suction strainer base 15.

[0054] The second bypass line 24 has a C-shaped profile in axial side view, with the inlet opening 26 of the second bypass line 24 located axially above an outlet opening 29 of the second bypass line 24 relative to the suction strainer base 17. The second bypass line 24 extends along its C-shaped profile into the projection 28, with the inlet opening 26 and the outlet opening 29 of the second bypass line 24 forming a common opening in the form of an axially extending elongated slot. Accordingly, the outlet opening 29 of the second bypass line 24 opens axially below the guide track 18 relative to the suction strainer base 17.

[0055] As previously described, at least one lateral suction opening 21 is provided on a suction strainer side wall 37 of the suction strainer 4. As further described from Figs. 1 and 3As can be seen in the plan view, the suction strainer 4 has a polygonal cross-section, namely a square-like cross-section, with the five lateral intake openings 21 arranged side by side in a row on each of the four side walls 37. The cuboid projections 28 are provided at the corners of the suction strainer 4, each extending linearly from the corresponding side walls 37. The cuboid projections 28 are arranged between two side walls 37 that extend linearly except for the projections 28, with the respective outlet opening 27 of the first bypass line 23 being located opposite one of the two suction strainer side walls 37 with respect to the projection 28, and substantially adjacent and orthogonal to the other of the two side walls 37.

[0056] Therefore, at least one bypass line 23, or the first bypass line 23, opens towards the suction strainer side wall 37 in such a way that a fluid flow exiting the at least one bypass line 23, or the first bypass line 23, flows along the suction strainer side wall 37, i.e., the fluid flow runs essentially parallel to the suction strainer side wall 37. As can be seen in particular from Fig. 1 To be recognized, the at least one bypass line 23 or the first bypass line 23 has a bend in particular before its outlet opening 23 such that the fluid flow exiting from the at least one bypass line 23 or from the first bypass line 23 is subjected to a swirl along the suction strainer side wall 37.

[0057] In other words, the outlet opening 27 of the at least one bypass line 23, or of the first bypass line 23, is arranged essentially orthogonally or at an angle ≥ 90° and ≤ 110°, in particular 100°, to the suction strainer side wall 37. The outlet opening 27 and the five lateral intake openings 21 thus extend at an angle ≥ 90° and ≤ 110°, in particular 100°, to each other. Furthermore, the outlet opening 27 is slightly inclined towards the suction strainer bottom 16, namely, it is arranged essentially axially or at an angle ≥ 0° and ≤ 20°, in particular 10°, to the axis 5 away from the impeller 2.

[0058] As mentioned previously, the outlet opening 27 is located at the level of the suction strainer base 15 and thus axially below the lateral intake openings 21. Due to the inclined arrangement, the fluid flow is directed below the lateral intake openings 21. As also previously described, the first four bypass lines 23 open at respective corners. It is also possible, although not shown, for two first bypass lines 23 to open at a common corner in opposite directions.

[0059] As in Fig. 3 As partially shown or recognizable, four guide tracks 18 arranged at regular intervals are provided in the inner wall of the suction strainer 16, which are designed as rectangular grooves in cross-section extending radially into the inner wall of the suction strainer 16 and corresponding to the guide lugs 14. Fig. 4Figure 16 shows one of the guide tracks 18 in a top view of the inner wall of the suction strainer 16. By means of the guide lugs 14, which engage in the guide tracks 18 in a form-fitting manner with respect to the cross-section, the centrifugal chamber 3 and the suction strainer 4 can be moved relative to each other into five different positions, indicated in Figure 1. Fig. 4 by circling the guide lugs 14, twisting and / or shifting.

[0060] Starting on the left in Fig. 4The guide track 18 initially extends axially towards the suction strainer base 15, then continues orthogonally to it at the same axial height. The fifth position 35 lies at this intersection between the axial extension and the extension at the same axial height, where the suction strainer 4 can be axially removed from or placed onto the centrifugal chamber 3. At this same axial height, next to the fifth position 35 and spaced apart from each other, are the first position 31, the third position 33, and the fourth position 34, while the second position 32 is arranged axially spaced below the third position 33 in the direction of the suction strainer base 15. Accordingly, the guide track 18 extends, or is bounded at the same axial height, by the fifth position 35 on one side and by the fourth position 34 on the other.In the area of ​​the first position 31, the guide track 18 branches off in a T-shape, initially running axially towards the suction basket base 15 and then orthogonally to it at the same axial height up to the second position 32.

[0061] In the first position 31, which is assumed in the normal operation of the centrifugal pump 1, both the side and bottom suction openings 19, 21 are open, while the pressure outlet 12 is closed. Fig. 5Figure 31 shows the first position, namely a part of the guide track 18 with the guide nose 14, shown in an axial sectional view at the top and in an axial top view at the bottom. As can be seen in the upper figure, the pressure outlet 12 is in contact with the bottom of the guide track 18 and is thus sealed by the bottom of the guide track 18. Therefore, no fluid can enter the first and second bypass lines 23, 24 from the pressure outlet 12. The centrifugal chamber 3 is arranged axially above the lateral intake openings 21 with respect to the suction strainer base 15, so that the lateral intake openings 21 are open. Through the lateral and bottom intake openings 19, 21 thus opened - Fig. 5 only shows the side intake openings 21 - fluid can be drawn in and conveyed through the impeller 2.

[0062] Fig. 6Figure 33 shows the third position of a so-called "twister operation," again depicted as a portion of the guide track 18 with the guide nose 14 shown in an axial sectional view at the top and in an axial top view at the bottom. Compared to the first position 31, the centrifugal chamber 3 and the suction strainer 4 are axially rotated relative to each other at the same axial height. Accordingly, both the lateral and bottom suction openings 19, 21 remain open. Due to the rotation, the pressure outlet 12 is no longer closed by the bottom of the guide track 18, but instead opens at the inlet opening 25 of the first bypass line 23, which is thus fluid-tightly connected to the pressure outlet 12. Consequently, a portion of the fluid pumped by the impeller 2 flows through the pressure outlet 12 into the first bypass line 23 and exits at the outlet opening 27 of the first bypass line 23 to flush the centrifugal pump 1.

[0063] Fig. 7The fourth position 34 shows the backflushing of the suction strainer 4, again shown as part of the guide track 18 with the guide nose 14 shown in an axial sectional view at the top and in an axial top view at the bottom. Compared to the third position 33, the centrifugal chamber 3 and the suction strainer 4 are rotated axially even further relative to each other at the same axial height than in the first position 31. Accordingly, both the lateral and bottom suction openings 19, 21 remain open. Due to this further rotation, the pressure outlet 12 is no longer closed by the bottom of the guide track 18, nor is it closed by the inlet opening 25 of the first bypass line 23, but now only by the inlet opening 26 of the second bypass line 24, which is thus fluid-tightly connected to the pressure outlet 12.Accordingly, the portion of the fluid conveyed by the impeller 2 flows through the pressure outlet 12 into the second bypass line 24 and flows out at the outlet opening 29 of the second bypass line 23 into the suction basket 4 in order to flush the suction basket 4.

[0064] Fig. 8 Figure 32 shows the second position in an axial sectional view for the so-called flat suction. In the second position 32, as described above, the centrifugal chamber 3 is arranged axially deeper within the suction strainer 4 relative to the suction strainer base 15, or the suction strainer 4 is attached axially higher to the centrifugal chamber 3 than in all other positions. Specifically, the centrifugal chamber 3 rests axially on the suction strainer base 15 or the suction strainer 4. The pressure outlet 12 rests in contact with the bottom of the guide track 18 and is thus sealed by the bottom of the guide track 18.

[0065] While in all other previously described positions the centrifugal chamber 3 is arranged axially above the lateral intake openings 21 with respect to the suction strainer base 15, in the second position 32 the centrifugal chamber 3, with its outer wall 13, rests against the lateral intake openings 21 and thus closes them. The intake openings 19 on the bottom side, through which fluid is conveyed by means of the impeller 2, remain open. For this purpose, below the suction strainer 4, as shown in the figure, Fig. 9 As can be seen, several pie-shaped feed channels 30 extending radially towards the bottom-side suction openings 19 are formed on the suction strainer base 15. The feed channels 30 are radially bounded by radially extending, cuboid-shaped feet 36 provided on the suction strainer base 15.

[0066] Finally, the centrifugal chamber 3 and the suction strainer 4, or the guide nose 14 and the guide track 18, are designed to be lockable relative to each other in the first, second, third, and fourth positions 31, 32, 33, 34, so that the corresponding position 31, 32, 33, 34 is maintained during fluid conveyance. Furthermore, the centrifugal chamber 3 and the suction strainer 5 are radially sealed against each other, in particular by means of a sealing lip.

[0067] 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 arranged accordingly in an embodiment of another category. Reference symbol list centrifugal pump 1 balance bike 2 gyroscope 3 suction strainer 4 axis 5 shovel 6 gyroscope chamber recess 7 plate 8 rotary chamber floor 9 gyratory chamber inner wall 10 Main pressure outlet 11 Pressure outlet 12 gyratory chamber outer wall 13 Leading nose 14 Suction basket floor 15 Suction strainer inner wall 16 Suction strainer recess 17 Guide track 18 Bottom-side suction opening 19 opening 20 Side intake opening 21 suction basket rim 22 First bypass line 23 Second bypass line 24 Entry opening of the first bypass line 25 Entry opening of the second bypass line 26 Exit opening of the first bypass line 27 Cantilever 28 Exit opening of the second bypass line 29 feed channel 30 First position 31 Second position 32 Third position 33 Fourth position 34 Fifth position 35 Foot 36 Suction strainer side wall 37

Claims

1. Centrifugal pump (1) with an impeller (2) defining an axis (5) for pumping a fluid, a centrifugal chamber (3) in which the impeller (2) is axially arranged, and a suction strainer (4) in which the centrifugal chamber (3) is axially arranged, wherein the suction strainer (4) has at least one lateral suction opening (21) provided on a suction strainer side wall (37) of the suction strainer (4) for drawing in the fluid and at least one bypass line (23) that can be supplied with a portion of the fluid pumped by the impeller (2) for flushing the centrifugal pump (1), and the at least one bypass line (23) opens in the direction of the suction strainer side wall (37) in such a way that a fluid flow exiting the at least one bypass line (23) flushes along the suction strainer side wall (37).

2. Centrifugal pump (1) according to the preceding claim, wherein an outlet opening (27) of the at least one bypass line (23) is arranged substantially orthogonally or at an angle ≥ 70°, ≥ 80°, or ≥ 90° and ≤ 110°, in particular 100° to the suction strainer side wall (37).

3. Centrifugal pump (1) according to one of the preceding claims, wherein an outlet opening (27) of the at least one bypass line (23) is arranged substantially axially oriented or at an angle ≥ 0° and ≤ 20°, in particular 10° to the axis (5) away from the impeller (2).

4. Centrifugal pump (1) according to one of the preceding claims, wherein the suction strainer (4) has a polygonal cross-section, at least one bypass line (23) opens at a corner of the suction strainer (4) and in particular an outlet opening (27) of the at least one bypass line (23) is oriented towards an opposite corner.

5. Centrifugal pump (1) according to one of the preceding claims, wherein the at least one bypass line (23) opens in such a way as to be oriented towards the suction strainer side wall (37) that the fluid flow flows parallel to the suction strainer side wall (37) along it.

6. Centrifugal pump (1) according to one of the preceding claims, wherein the at least one bypass line (23) opens axially below the at least one lateral suction opening (21) with respect to the impeller (2), in particular such that the fluid flow exiting the at least one bypass line (23) flows below the at least one lateral suction opening (21).

7. Centrifugal pump (1) according to one of the preceding claims, wherein the at least one bypass line (23) has a rectangular outlet opening (27) for the exit of the fluid flow, the longitudinal sides of which are in particular orthogonal to the axis (5).

8. Centrifugal pump (1) according to the preceding claim, wherein the at least one bypass line (23) has a bend in particular before its outlet opening (27) such that the fluid flow exiting the at least one bypass line (23) is subjected to a swirl along the suction strainer side wall (37).

9. Centrifugal pump (1) according to one of the preceding claims, wherein the suction strainer (4) has a rectangular cross-section with four radial suction strainer side walls (37) extending substantially or at least partially linearly and four bypass lines (23) such that the fluid flows exiting the bypass lines (23) flush along the four side walls (37).

10. Centrifugal pump (1) according to the preceding claim, wherein the four bypass lines (23) terminate at respective corners or two bypass lines (23) terminate at a common corner in opposite directions.

11. Centrifugal pump (1) according to one of the preceding claims, wherein the suction strainer (4) has a plurality of lateral suction openings (21) arranged in particular at regular intervals and / or at the same axial height, at least one of which has a rectangular, in particular square, cross-section and / or several spaced-apart groups of at least one lateral suction opening (21) are provided.

12. Centrifugal pump (1) according to one of the preceding claims, wherein the centrifugal chamber (3) has at least one pressure outlet (12) leading from the impeller (2) to the suction strainer (4) for receiving the portion of the fluid pumped by the impeller (2), which is connectable to at least one bypass line (23) for flushing the centrifugal pump (1) and / or the suction strainer (4), and the centrifugal chamber (3) and the suction strainer (4) are rotatable and / or axially displaceable relative to each other in at least one first, one second and one third position (31, 32, 33) such that at least in the first position (31) the at least one lateral suction opening (21) is open, in the second position (32) the at least one lateral suction opening (21) is deactivated and in the third position (33) the at least one pressure outlet (12) is connected to the at least one bypass line (23) is connected.

13. Centrifugal pump (1) according to the preceding claim, wherein in the first position (31) and in the second position (32) the at least one pressure outlet (12) and / or the at least one bypass line (23) is deactivated, the suction strainer (4) has at least one bottom suction opening (19) for drawing in the fluid, and in the second position (32) only the bottom suction opening (19) is open, in the third position (33) the at least one side suction opening (21) is open, and / or only in the third position (33) the at least one pressure outlet (12) is connected to the at least one bypass line (23).

14. Centrifugal pump (1) according to one of the two 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.

15. Centrifugal pump (1) according to one of the three preceding claims, wherein the centrifugal chamber (3) has at least one main pressure outlet (11) for receiving a large part of the fluid pumped by the impeller (2) and the at least one pressure outlet (12) is arranged in the region of the at least one main pressure outlet (11).

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