Volute module

Abstract

Volute modules for single-stage and multi-stage centrifugal pumps are described and claimed. The volute module includes a body defining a volute surrounding an impeller chamber. The volute module also includes an unencapsulated impeller in the impeller chamber. By placing an additional impeller housing in the impeller chamber, the volute module can be used as part of a multi-stage centrifugal pump. However, the last stage of the volute module is always formed by an unencapsulated impeller, the flow of which is directed towards the volute, and the same body can be used for single-stage and multi-stage centrifugal pumps. A single-stage centrifugal pump and a multi-stage centrifugal pump including the volute module are further described and claimed.

Description

Technical Field

[0001] The present invention is directed to a volute module for a single-stage centrifugal pump and a multi-stage centrifugal pump. In addition, the present invention is directed to a single-stage centrifugal pump including a volute module and a multi-stage centrifugal pump including a volute module. Background Art

[0002] Single-stage centrifugal pumps and multi-stage centrifugal pumps are generally well known in the prior art. In a single-stage centrifugal pump, a single impeller is rotatably arranged within an impeller chamber. The impeller is driven by a drive device (e.g., an electric motor) and accelerates the pump fluid drawn into the impeller chamber through the inlet toward the pressure outlet. The kinetic energy of the rotating pump fluid is typically converted into static pressure at the pressure outlet with the help of a volute, which surrounds the impeller chamber and conveys the rotating fluid toward the pressure outlet.

[0003] To increase pump head, a multistage centrifugal pump includes multiple stacked impellers. Each impeller is located within a separate impeller housing. The pump fluid flows into the initial-stage impeller housing, which houses the first, or initial, impeller. The impeller transfers energy from the motor to the pump fluid. Guide vanes formed inside the initial-stage impeller housing, which encloses the initial impeller, convert the rotation of the pump fluid into pressure and direct the pump fluid flow toward the subsequent stages of the multistage centrifugal pump.

[0004] Subsequent pump stages are similarly formed by impellers enclosed in impeller housings. The pump fluid supplied by the initial pump stage is set into rotation by the impellers. The impeller housings of subsequent impeller stages also include guide vanes, which convert the rotation of the pump fluid into pressure and direct the flow of the pump fluid to another subsequent impeller stage or to the pressure outlet of the multi-stage centrifugal pump.

[0005] The many different requirements placed on single-stage and multistage centrifugal pumps have led to a large number of different models for different applications. In particular, specialized pumps exist for many different pump head and flow requirements. This large number of different pumps complicates pump manufacturing and increases manufacturing costs due to the large number of different components and the many different tools required to manufacture these components. Summary of the Invention

[0006] In view of the above, an object of the present invention may be seen as simplifying pump production by reducing the number of components required to provide single-stage centrifugal pumps and multi-stage centrifugal pumps.

[0007] This object is achieved by a volute module, a single-stage centrifugal pump and a multi-stage centrifugal pump according to the independent claims. Preferred embodiments of the invention are subject matter of the dependent claims.

[0008] In a first aspect, the problem underlying the present invention is solved by a volute module for single-stage and multi-stage centrifugal pumps. The volute module comprises at least a portion of a main body defining an impeller chamber and a volute at least partially surrounding the impeller chamber. The volute module also comprises an unencapsulated impeller rotatable about a drive axis in the impeller chamber. The volute module is configured such that a rotating flow of pump fluid generated by the unencapsulated impeller is directed toward the volute, which delivers the rotating flow of pump fluid toward a pressure outlet of the volute module. When the pump housing is used as part of a multi-stage centrifugal pump, the volute module also comprises an initial-stage impeller housing located in the impeller chamber. The initial-stage impeller housing encloses an impeller rotatable about the drive axis and defines guide vanes that direct the flow of pump fluid from the impeller of the initial-stage impeller housing to the impeller of a subsequent stage of the multi-stage impeller pump. The subsequent stage of the multi-stage impeller pump is formed by either an unencapsulated impeller or an intermediate-stage impeller housing that encloses an impeller rotatable about the drive axis and defines guide vanes.

[0009] In other words, the same volute module can be used for both single-stage centrifugal pumps and multi-stage centrifugal pumps. The volute module forms an impeller chamber that accommodates one or more impellers, depending on whether it is configured as a single-stage pump or a multi-stage pump. The impeller chamber is at least partially formed by the main body of the volute module, which can form the side walls and bottom wall of the impeller chamber. The main body of the volute module (which also defines the volute) and the pressure outlet can, for example, be formed as a single workpiece and can, for example, be made of cast iron, titanium, stainless steel, a plastic material, a composite material or any other material suitable for the application. For example, the main body of the volute can be manufactured using a traditional casting process, a 3D printing process or any other process suitable for the component.

[0010] At least a portion of the side wall or outer wall of the impeller chamber may additionally be formed by a sleeve.The use of a sleeve is particularly beneficial when the volute module is used as part of a multi-stage centrifugal pump.

[0011] In any case, an unencapsulated impeller is arranged in the impeller chamber of the volute module. Since this impeller is not arranged inside or encapsulated by another impeller housing placed inside the impeller chamber, it is referred to as an unencapsulated impeller. Therefore, the pump fluid set into rotation by the unencapsulated impeller is always directed toward the inner surface of the outer wall of the volute module and, therefore, toward the volute formed at the periphery of the impeller chamber.

[0012] If the volute module is used as a single-stage centrifugal pump, some or all of the rotating flow generated by the unencapsulated impeller can be accelerated directly from the unencapsulated impeller toward the volute. In particular, if the volute module is used as part of a multi-stage centrifugal pump, the rotating flow may have to flow along the inner surface of the impeller chamber. The inner surface of the impeller chamber may be formed by a sleeve or, if the unencapsulated impeller is not aligned with the volute, by the body of the volute module.

[0013] In any case, no guide vanes are provided in the volute module, which would convert the rotating flow of the pump fluid generated by the unpackaged impeller into a linear flow before it hits the volute and is subsequently guided by the volute. In particular, no guide vanes are provided, which would divert the flow of the unpackaged impeller away from the bottom wall of the impeller chamber and / or towards the drive axis of the unpackaged impeller. In all embodiments, the volute converts the rotating flow of the pump fluid into a linear flow that is directed towards the pressure outlet of the volute module. Therefore, regardless of whether the volute module is used as part of a single-stage centrifugal pump or a multi-stage centrifugal pump, the same volute is used to convert the rotation of the last or final impeller in the impeller chamber (which is always an unpackaged impeller). If the volute module is used as part of a single-stage centrifugal pump, the final or last impeller is also the first or initial impeller arranged in the volute module.

[0014] If the volute module is used as part of a multi-stage centrifugal pump, the initial stage impeller housing is placed in the impeller chamber. This initial stage impeller housing surrounds a first impeller that receives an incoming flow of pump fluid from outside the pump. This impeller (which may also be referred to as the initial stage impeller) is also rotatable about the drive axis and causes the pump fluid to rotate to generate pressure. The initial stage impeller housing also includes so-called guide vanes that are configured to convert the rotational flow of the initial stage impeller into a linear flow that flows in a direction parallel to the drive axis toward subsequent stages of the multi-stage pump (i.e., away from the bottom wall of the impeller chamber).

[0015] Depending on the number of stages of the multi-stage centrifugal pump, the subsequent stages of the pump can be formed by unencapsulated impellers or intermediate stage impeller housings. If the subsequent stages of the initial stage impeller housing are formed by unencapsulated impellers, the multi-stage centrifugal pump is a two-stage pump. Otherwise, one or more intermediate stage impeller housings can be stacked on top of each other to form a multi-stage centrifugal pump with more than two pump stages. The number of pump stages corresponds to the number of impellers placed in the impeller chamber. Each of the intermediate stage impeller housings encapsulates an impeller that is rotatable about the drive axis and also includes guide vanes that guide the rotating flow generated by the corresponding impeller placed inside the intermediate stage impeller housing towards the subsequent stages of the multi-stage centrifugal pump. It is particularly noteworthy that in this case, the outer wall of the impeller chamber does not have to be completely formed by the main body of the volute module.

[0016] In summary, the volute module can be used for both single-stage centrifugal pumps and multi-stage centrifugal pumps. To this end, the impeller chamber formed by the volute module, in particular the body of the volute module, is configured such that: for use as part of a single-stage centrifugal pump, only the unencapsulated impeller is mounted in the impeller chamber, whereas for use as a multi-stage centrifugal pump, in addition to the unencapsulated impeller, at least the initial stage impeller housing and possibly one or more additional intermediate stage impeller housings may also be mounted in the impeller chamber.

[0017] In any configuration, the volute module encloses an unencapsulated impeller disposed in an impeller chamber. When the volute module is used as part of a single-stage centrifugal pump, it includes only the unencapsulated impeller and not the initial-stage impeller housing. Nevertheless, the impeller chamber is designed to include not only the unencapsulated impeller, but also to accommodate at least the initial-stage impeller housing and possibly other intermediate-stage impeller housings. This advantageously improves efficiency by eliminating the last impeller housing in a multi-stage arrangement. In addition, the height required along the drive axis of a pump without a last impeller housing is less, resulting in a more compact design. Furthermore, the number of components required to provide a large number of single-stage and multi-stage pumps is reduced, which simplifies the production of the pump.

[0018] In a preferred embodiment, the volute is delimited in the direction of the drive axis by an upper edge and a lower edge. The unencapsulated impeller comprises a lower base plate, an upper base plate, and at least one impeller blade arranged between the upper and lower base plates. The upper and lower base plates may, for example, extend parallel to each other and perpendicular to the drive axis, but may also have different configurations. In the direction of the drive axis, the distance between the outer edge of the upper base plate and the outer edge of the lower base plate is smaller than the distance between the lower edge of the volute and the upper edge of the volute.

[0019] In other words, in a preferred embodiment, the height of the unencapsulated impeller in the direction of the drive axis is less than the height of the volute in the direction of the drive axis. Here, the height of the unencapsulated impeller will be defined as the distance between the outer edge of the upper base plate of the impeller and the outer edge of the lower base plate of the impeller.

[0020] Similarly, the height of the volute is defined by the distance between the upper and lower edges of the volute facing the impeller chamber. Preferably, the plane in which the upper edge extends is parallel to the plane in which the lower edge extends. Even more preferably, the upper and lower edges extend in a plane perpendicular to the drive axis. If the upper and lower edges of the volute should not extend in parallel planes, the height of the impeller should, for example, be less than the minimum distance between the upper and lower edges of the volute.

[0021] In an exemplary preferred embodiment, the distance between the outer edges of the upper and lower base plates is preferably 70% or less, more preferably 50% or less, of the distance between the lower and upper edges of the volute.

[0022] In a preferred embodiment in which the volute is delimited in the direction of the drive axis by an upper edge and a lower edge, the circumference of the upper edge of the volute is greater than the circumference of the lower edge of the volute. Thus, in a preferred embodiment, the impeller chamber is wider at the upper edge of the volute than at the lower edge of the volute.

[0023] When the upper and lower edges extend in parallel planes, the cross-sectional area of the impeller chamber defined by the lower edge of the volute is smaller than the cross-sectional area of the impeller chamber defined by the upper edge of the volute. This facilitates pump fluid flow when the volute module is used as part of a multi-stage centrifugal pump and at least the initial stage impeller chamber is positioned within the impeller chamber. At the same time, when the volute module is used as part of a single-stage pump, the volute is positioned as close as possible to the drive axis at the lower edge, minimizing the distance that the flow accelerated by the unencapsulated impeller must travel before being collected by the volute.

[0024] In an exemplary preferred embodiment, both the upper edge and the lower edge of the volute are circular, and the radius of the circular upper edge is greater than the radius of the circular lower edge. The advantages of this configuration correspond to those of the aforementioned embodiment.

[0025] In another preferred embodiment, the lower edge of the volute defines a bottom wall of the impeller chamber. The bottom wall surrounds an inlet opening for the pump fluid.

[0026] Thus, in a preferred embodiment, the lower edge of the volute simultaneously forms the outer edge of the bottom wall of the impeller chamber. The bottom wall includes a preferably centrally located circular inlet opening through which the pump fluid is drawn into the impeller chamber by the first impeller of the volute module. For example, when the volute module is used as part of a single-stage centrifugal pump, this first impeller can be an unencapsulated impeller, or if the volute module is used as part of a multi-stage centrifugal pump, this first impeller can be the impeller of the initial stage impeller housing.

[0027] Preferably, the bottom wall extends generally perpendicular to the drive axis, and the center of the inlet opening is further preferably aligned with the drive axis.

[0028] Generally speaking, it is preferred that the pump housing is constructed so that: when the volute module is used as part of a multi-stage centrifugal pump, the pump fluid is drawn into the impeller chamber only by the impeller of the initial stage impeller housing, and when the volute module is used as part of a single-stage centrifugal pump, the pump fluid is drawn into the impeller chamber by the unencapsulated impeller.

[0029] In a preferred embodiment, the distance of the inner surface of the volute facing the impeller chamber from the drive axis increases in a plane extending perpendicular to the drive axis, starting from the inlet region of the volute, until the volute transitions into the pressure outlet of the volute module. A volute tongue, which separates the inlet region of the volute from the pressure outlet of the volute module, is inclined away from the drive axis when viewed from the lower edge of the volute to the upper edge of the volute.

[0030] Therefore, in a preferred embodiment, the depth of the volute measured in a plane extending perpendicular to the drive axis increases from the volute tongue to the region where the volute transitions into the pressure outlet of the volute module. Thus, the rotating flow generated by the unencapsulated impeller is directed towards the pressure outlet.

[0031] In another preferred embodiment, the volute module is configured such that when the volute module is used as part of a multi-stage centrifugal pump, the rotating flow of the pump fluid generated by the unencapsulated impeller flows away from the unencapsulated impeller towards the outer wall of the impeller chamber where it is directed into the volute.

[0032] Therefore, in a preferred embodiment, the volute module comprises an outer wall which directs the flow generated by the final stage of the multistage pump into or towards the volute and, therefore, into or towards the pressure outlet of the volute module. The outer wall may also be formed by the body of the volute module. However, it is preferred that the section of the outer wall which redirects the flow of the unencapsulated impeller of the multistage centrifugal pump is formed by an additional sleeve which is placed on the body to extend the outer wall and increase the size of the impeller chamber to accommodate the additional pump stage. The advantage of using a sleeve to provide the outer wall is that sleeves of different sizes can be used to adapt the outer wall to multistage centrifugal pumps having different numbers of stages. For example, a specific sleeve can be provided for each number of stages.

[0033] In a preferred embodiment, the volute module includes a chamber support, the inner surface of the chamber support facing the drive axis partially surrounding the impeller chamber, and configured to guide the rotational flow of the pump fluid generated by the unencapsulated impeller into the volute.

[0034] Therefore, in a preferred embodiment, a chamber support is provided, which serves as the upper end of the impeller chamber, i.e., it delimits the impeller chamber on the side facing away from the bottom wall of the impeller chamber. For example, the chamber support can also be used to support the volute module on a motor support or motor base, which is also part of the multi-stage centrifugal pump, or to attach the volute module to the motor support or motor base.

[0035] Furthermore, when the volute module is used as part of a multi-stage centrifugal pump, a chamber support can be provided for holding the last impeller housing in the impeller chamber in place in a plane perpendicular to the drive axis, and the chamber support can also be used to apply forces on the sleeve and any impeller housings within the impeller chamber that are directed toward the body of the volute module. For example, the forces or loads acting on the sleeve and one or more impeller housings can be generated using stay bolts used to attach the motor mount to the volute module.

[0036] The inner surface of the chamber support also acts as a guide surface that directs the rotating flow generated by the unpackaged impeller toward the volute. As previously mentioned, the unpackaged impeller does not include a casing, and the flow is primarily directed toward the volute by the inner surface of the body of the volute module and the inner surface of the chamber support.

[0037] When the volute module is used as part of a multi-stage pump, the volute module is preferably further configured such that the rotational flow of the pump fluid generated by the unencapsulated impeller is guided by the chamber support to flow between the outer surface of the initial stage impeller housing and the inner surface of the impeller chamber toward the volute. Thus, when the volute module is used as part of a multi-stage pump, the flow is further guided by the outer surface of any impeller housing placed in the impeller chamber and the inner surface of the outer wall of the impeller chamber. For example, the outer wall may be formed by a sleeve.

[0038] In a preferred embodiment, the volute module includes at least one end guide vane for redirecting the rotating flow of pump fluid generated by the unencapsulated impeller toward the volute. Preferably, the at least one end guide vane is part of the chamber support. Furthermore, in an exemplary preferred embodiment, the at least one end guide vane also has a structural function, as it can be used to transfer loads applied by support bolts that mount the motor mount to the base of the volute module to one or more internal impeller housings. This holds the impeller housings in place.

[0039] Preferably, the chamber support comprises 3 to 7 end guide vanes, even more preferably 4 end guide vanes.

[0040] Therefore, in a preferred embodiment, at least one dedicated end guide vane is provided to improve the flow of the rotating pump fluid accelerated by the unencapsulated impeller toward the volute. The one or more end guide vanes support the flow of the pump fluid away from the drive axis. These end guide vanes can also help redirect the flow in a direction parallel to the drive axis. Furthermore, the guide vanes can preferably direct the pump fluid away from the unencapsulated impeller and the top wall of the impeller housing formed by the chamber support toward the bottom wall of the volute module and the body of the volute module.

[0041] In an exemplary embodiment where a volute module is used as part of a multi-stage pump, the flow will be redirected toward the region of the impeller chamber where the initial stage impeller chamber is located. Thus, the end guide vanes direct the rotating flow generated by the unpotted impeller in a direction opposite to the guide vanes of the initial stage impeller housing and any intermediate stage impeller housings (i.e., away from the drive axis) and also toward the bottom wall of the volute module and the volute.

[0042] In a preferred embodiment, the end guide vanes are formed on a chamber support member that delimits the impeller chamber toward the motor mount. For example, the motor mount may be attached to the main body of the volute module via support bolts. Thus, the chamber support member will be configured to transfer the loads generated by the support bolts to the inner impeller housing and sleeve disposed within the impeller chamber, thereby holding them in place and achieving a tight connection between the components of the pump housing. In this case, the guide vanes formed on the chamber support member may also be configured to transfer these loads from the motor mount to the impeller housing or impeller housings.

[0043] In a second aspect, the problem underlying the present invention is solved by a single-stage centrifugal pump comprising a volute module according to any of the preceding embodiments and a motor housing attached to the volute module. The volute module includes an unencapsulated impeller but does not include an initial-stage impeller housing and an intermediate-stage impeller housing. The advantages and specific embodiments of the single-stage centrifugal pump correspond to the embodiments of the volute module used as part of the single-stage centrifugal pump.

[0044] The volute module in this embodiment is part of a single-stage centrifugal pump. However, since at least the body of the volute module, which defines the volute and part of the impeller chamber, allows for placement of an initial stage impeller housing and one or more intermediate stage impeller housings therein, the volute module can be identified as a volute module that can also be suitable for a multi-stage centrifugal pump.

[0045] In another aspect, the problem on which the present invention is based is solved by a multi-stage centrifugal pump comprising an embodiment of a volute module as described above and a motor housing.The volute module comprises an unencapsulated impeller and an initial stage impeller housing.

[0046] In an exemplary preferred embodiment of the multi-stage centrifugal pump, the volute module further includes one or more intermediate-stage impeller housings. Each intermediate-stage impeller housing encloses an impeller rotatable about the drive axis and includes guide vanes that direct the flow of pump fluid from the impeller of the corresponding intermediate-stage impeller housing to the impeller of a subsequent stage of the multi-stage centrifugal pump. Subsequent stages of the multi-stage centrifugal pump are formed by either an unenclosed impeller or another intermediate-stage impeller housing.

[0047] The advantages of the multistage centrifugal pump correspond to the advantages of the embodiments of the volute module used therein. It should be noted that in any case at least the body of the volute module of the multistage centrifugal pump and the unencapsulated impeller can also be used for a single-stage centrifugal pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Exemplary embodiments of the volute module and the single-stage centrifugal pump and the multi-stage centrifugal pump will be described below with reference to the accompanying drawings, wherein

[0049] Figure 1 shows a partial cross-sectional view of an exemplary embodiment of a volute module for use as part of a single-stage centrifugal pump,

[0050] Figure 2 Shown Figure 1 An isometric cross-sectional view of an embodiment of

[0051] Figure 3 Shown Figure 1 A partial cross-sectional view of an exemplary embodiment of a volute module shown as part of a multi-stage centrifugal pump, and

[0052] Figure 4 Shown Figure 4 A cross-sectional view of an embodiment of the present invention. DETAILED DESCRIPTION

[0053] Figure 1 and Figure 2 An exemplary embodiment of a volute module 1 included in a single-stage centrifugal pump 2 is shown. The volute module 1 includes a main body 1a that defines an impeller chamber 3 in which an unenclosed impeller 4 is disposed. The main body 1a of the volute module 3 also defines a volute 5 that surrounds the impeller chamber 3 and terminates in a pressure outlet 6 of the volute module 1. The main body 1a of the volute module 1, which defines the impeller chamber 3, the volute 5, and also the pressure outlet 6, is made from a single piece that has been manufactured using conventional casting processes, plastic injection molding, 3D printing, or other suitable processes. For example, the main body 1a can be made of cast iron, stainless steel, titanium, plastic, or any other material suitable for the application.

[0054] The unencapsulated impeller 4 is rotatable about a drive axis 7 and is driven by means of a drive shaft 8 which may be connected to an electric motor (not shown). Figure 1 and Figure 2 The unpackaged impeller 4 is shown in its entirety, rather than in cross-section.

[0055] The lower end of the volute module 1 is formed by a bottom wall 9 which surrounds an inlet opening 10 through which the pump fluid is drawn or ingested into the impeller chamber 3 by means of the rotation of the unenclosed impeller 4. The bottom wall 9 is also part of the main body 1 a of the volute module 1 and is therefore formed as a single piece together with the wall which partially surrounds the impeller chamber 3 and defines the volute 5.

[0056] The periphery of the bottom wall 9 is formed by the circular lower edge 11 of the volute 5. The bottom wall 9 forms the lower end of the impeller chamber 3 because the bottom wall 9 is farthest from the motor driving the unenclosed impeller 4. The volute 5 is also delimited by an upper edge 12, which is Figure 1 and Figure 2 In the embodiment shown, the upper edge 12 also forms the upper end of the impeller chamber 3. The upper edge 12 is also circular.

[0057] like Figure 1 As can be seen in FIG, the circumference of the upper edge 12 of the volute 5 is greater than the circumference of the lower edge 11 of the volute. In other words, in a plane extending perpendicular to the drive axis 7, the impeller chamber 3 is wider at the upper edge 12 of the volute 5 than at the lower edge 11. Figure 3 and Figure 4 As discussed, this design of the impeller chamber 3 and the volute 5 allows the main body 1 a of the volute module 1 to be used also for a multi-stage centrifugal pump.

[0058] The width of the impeller chamber 3 in a plane perpendicular to the drive axis 7 can also be expressed in terms of the radius of the circular lower edge 11 and upper edge 12 of the volute 5. Thus, the radius of the lower edge 11 of the volute 5 around the drive axis 7 is smaller than the radius of the upper edge 12.

[0059] The volute 5 is provided for directing the circulating flow of the pump fluid generated by the unencapsulated impeller 4 to the pressure outlet 6 of the volute module 1. To this end, the inner surface 14 of the body 1a defining the volute 5 is formed so that, in a plane extending perpendicular to the drive axis 7, the distance of the inner surface 14 facing the drive axis 7 increases from a tongue 15 of the volute 5 to the region where the volute 5 transitions into the pressure outlet 6. This region is not shown in the figures, and the tongue 15 is defined as the portion of the body 1a of the volute module 1 that separates the inlet region of the volute 5 closest to the drive axis 7 from the pressure outlet 6.

[0060] It should be noted that the distance of the inner surface 14 from the drive axis depends on a plane extending perpendicular to the drive axis 7 at which the distance from the drive axis 7 is established. Figure 1 and Figure 2 As can be further seen in FIG, the volute 5 can include an inner surface 14 facing away from the drive axis 7. In a plane including both the surface facing away from the drive axis 7 and the surface facing toward the drive axis 7, the distance from the drive axis 7 increases from the tongue 15 to the area where the volute 5 merges into the pressure outlet 6, at least for the surface facing toward the drive axis 7.

[0061] like Figure 1 As can be further seen in FIG, when the partition tongue 15 is projected onto a plane extending parallel to the drive axis 7 or through the drive axis 7, the partition tongue 15 is inclined away from the drive axis 7 in the direction from the lower edge 11 to the upper edge 12 of the volute 5. This inclination also accommodates the increase in the width of the impeller chamber 3 in the direction away from the bottom wall 9. As will be described later on Figure 3 and Figure 4 As explained in detail, this increase in the width of the impeller chamber 3 allows the use of multi-stage centrifugal pumps Figure 2 The main body 1 a of the volute module 1 is shown.

[0062] The unpackaged impeller 3 comprises a lower base plate 16 and an upper base plate 17, and a plurality of impeller blades 18 are arranged between the lower base plate 16 and the upper base plate 17. Figure 1 As can be best seen in FIG, the distance between the outer edge 16a of the lower base plate 16 and the outer edge 17a of the upper base plate 17 of the impeller is approximately 50% of the distance between the lower edge 11 and the upper edge 12 of the volute 5 in the direction of the drive axis 7. If the main body 1a is used as part of a volute module 1 of a multi-stage centrifugal pump, the height difference serves to improve the pump fluid flow.

[0063] Figure 3 and Figure 4 An exemplary embodiment of a volute module 1 as part of a multi-stage centrifugal pump 19 is shown. Figure 3 and Figure 4 The multistage centrifugal pump 19 shown in FIG. Figure 1 and Figure 2 The exemplary embodiment of the volute module 1 shown, and in particular, uses the same exemplary embodiment of the main body 1 a and the same unencapsulated impeller 4 .

[0064] For the sake of brevity, only Figure 3 and Figure 4 Discussion of the volute module 1 has not yet been made about Figure 1 and Figure 2 For other aspects, reference is made to the description of the aforementioned figures.

[0065] The multistage centrifugal pump 19 comprises two stages, i.e., two impellers 4, 20. Figure 3 In the figure, only the unpackaged impeller 4 is visible, which is Figure 1 and Figure 2 The unencapsulated impeller 4 shown in FIG is the same impeller 4 .

[0066] The second impeller 20 (also referred to as the initial stage impeller 20) is disposed inside an initial stage impeller housing 21, which is disposed inside the impeller chamber 3. The initial stage impeller 20 is rotatable about the drive axis 7 and is also driven by the drive shaft 8. Figure 4 As can be seen in FIG, the drive shaft 8 can be provided in multiple parts, thereby further enhancing the modularity of the pump housing 2, 19.

[0067] The pump fluid flows through the inlet opening 10 into the initial impeller housing 21 where it is energized by the initial stage impeller 20. Figure 4 As can be seen in FIG, the initial impeller housing 21 includes or defines guide vanes 22 that redirect the circulating flow of pump fluid generated by the initial impeller 20 toward the drive axis 7 and upwardly toward subsequent stages of the multi-stage centrifugal pump 19. Upward here refers to a direction away from the bottom wall 9 of the volute module 1 and toward the motor bracket or chamber support 23.

[0068] The guide vanes 22 thus transform the rotation of the pump fluid into pressure, which is then taken up by the unencapsulated impeller 4 , which represents the second and therefore final stage of the multi-stage centrifugal pump 19 .

[0069] like Figure 4As can be seen in the cross-sectional depiction of FIG, the upper base plate 16 and the lower base plate 17 of the initial stage impeller 20 and the unpackaged impeller 4 are not planar, but have complex shapes. As previously discussed, the height of the impeller 4 in the direction of the drive axis 7 is defined by the distance between the outer edge 16a of the upper base plate 16 and the outer edge 17a of the lower base plate 17, so the previously defined height can be determined for these impellers 4, 20.

[0070] The unencapsulated impeller 4 is also driven by the drive shaft 8 and sets the pump fluid received from the initial stage impeller 20 into rotation. The rotating flow is then directed between the outer surface 24 of the initial stage impeller housing 21 and the inner surface 25 of the impeller chamber 3 towards the volute 5 and thus towards the pressure outlet 6 of the volute module 1. The inner surface 25 of the impeller chamber 3 is partially formed by a sleeve 26, which is used to increase the size of the impeller chamber 3 to Figure 1 The single-stage centrifugal pump 2 is shown as a multi-stage centrifugal pump 19 .

[0071] If the multi-stage centrifugal pump 19 were to have more than two stages, a different sleeve 26 would be used that had a longer extension in the direction of the drive axis 7. Thus, the impeller chamber 3 can be easily adapted to a different number of pump stages without requiring a different body 1 a of the volute module 1 and a different unencapsulated impeller 4. Consequently, the number of required components is reduced and the production of the pump is simplified.

[0072] If only Figure 4 As can be seen in the figure, the volute module 1 further comprises a chamber support 27 on which the motor bracket or motor seat 23 is arranged. Thus, the chamber support 27 delimits the impeller chamber 3 towards the motor bracket. Furthermore, the chamber support applies a load on the sleeve 26 and the initial stage impeller housing 21 towards the main body 1a of the volute module 1 in order to hold the sleeve 26 and the impeller housing 21 in place and to make the sleeve 26 and the impeller housing 21 tightly abut against the main body 1a. For example, the load can be generated using support bolts (not shown) for fixing the motor bracket 23 to the main body 1a of the volute module 1. The motor bracket 23 is provided for connecting the volute module 1 to a motor or drive device (not shown).

[0073] In addition, the chamber support 27 defines one or more end guide vanes 29 that redirect the circulating flow generated by the unenclosed impeller 4 toward the gap extending between the outer surface 24 of the initial stage impeller housing 21 and the inner surface 25 of the sleeve 26 and further toward the volute 5 and the pressure outlet 6. The end guide vanes 29 are also part of the load transfer structure that is used to transfer the loads generated by the motor base 23 to the initial stage impeller housing 21 and the sleeve 26.

[0074] exist Figure 41 , only one of the end guide vanes 29 has been labeled with a reference numeral to keep the figure easy to understand. The end guide vane 29 is primarily provided for redirecting the rotating flow in a direction away from the second end 13 of the impeller chamber 3 and thus redirecting the rotating flow towards the bottom wall 9 of the volute module 1.

[0075] Therefore, in Figure 3 and Figure 4 In the illustrated exemplary embodiment of a multi-stage centrifugal pump 19, the rotating flow generated by the last or final impeller of the pump stage (which is formed by an unencapsulated impeller 4) flows directly toward the volute 5 and, therefore, the pressure outlet 6. In conventional multi-stage centrifugal pumps, additional guide vanes 22, similar to those in the initial-stage impeller housing 21, are provided. These guide vanes redirect the rotating flow of the final impeller toward the drive axis 7 and convert the flow's rotation into pressure. The resulting linear flow thus flows along the axis 8 (i.e., in the direction of the drive axis 7) toward the second end 13 of the impeller chamber 3. Here, the flow is redirected toward the pressure outlet 6 of a conventional multi-stage centrifugal pump. Compared to this conventional arrangement, efficiency is improved in this embodiment because the rotating flow is directed toward the volute 5 and the pressure outlet 6. Furthermore, since the impeller chamber 3 does not have to accommodate the impeller housing of the final-stage impeller 4, the overall height of the multi-stage centrifugal pump 19 is reduced, resulting in a more compact overall design.

[0076] Reference Signs List

[0077] 1 volute module

[0078] 1a The main body of the volute module

[0079] 2 single-stage centrifugal pump

[0080] 3 impeller chambers

[0081] 4 Unpackaged impeller

[0082] 5 volute

[0083] 6 pressure outlets

[0084] 7 drive axis

[0085] 8 drive shafts

[0086] 9 bottom wall

[0087] 10 Entrance opening

[0088] 11 Lower edge of the volute

[0089] 12 Upper edge of the volute

[0090] 13 Upper end of the impeller chamber

[0091] 14 Inner surface of the volute

[0092] 15 Tongue Separation

[0093] 16 Lower base plate without encapsulated impeller

[0094] 16a Outer edge of the lower substrate

[0095] 17 Upper base plate without encapsulated impeller

[0096] 17a Outer edge of lower substrate

[0097] 18 impeller blades

[0098] 19 Multistage centrifugal pump

[0099] 20 Primary stage impeller or second impeller

[0100] 21 Initial stage impeller casing

[0101] 22 Guide vanes in the initial stage impeller housing

[0102] 23 motor bracket / motor seat

[0103] 24 The outer surface of the initial stage impeller housing

[0104] 25 Inner wall of sleeve

[0105] 26 sleeve

[0106] 27 Chamber support

[0107] 29 End guide vanes

Claims

1. A volute module (1) for a single-stage centrifugal pump (2) and a multi-stage centrifugal pump (19), wherein: The volute module (1) comprises a body (1a) defining at least part of an impeller chamber (3) and a volute (5) at least partially surrounding the impeller chamber (3), and further comprises an unenclosed impeller (4) rotatable about a drive axis (7) in the impeller chamber (3), wherein the volute module (1) is configured such that the rotational flow of the pump fluid generated by the unpackaged impeller (4) is directed to the volute (5), which delivers the rotational flow of the pump fluid toward a pressure outlet (6) of the volute module (1), Wherein, when the pump housing is used as part of a multi-stage centrifugal pump (19), the volute module (1) further comprises an initial stage impeller housing (21) in the impeller chamber (3), wherein the initial stage impeller housing (21) encloses an impeller rotatable about the drive axis (7) and defines guide vanes that direct the flow of pump fluid from the impeller of the initial stage impeller housing (21) to the impeller of a subsequent stage of the multi-stage centrifugal pump (19), wherein the subsequent stage is formed by the unenclosed impeller (4) or an intermediate stage impeller housing that encloses an impeller rotatable about the drive axis (7) and defines guide vanes.

2. The volute module (1) according to claim 1, wherein: The volute (1) is delimited in the direction of the drive axis (7) by an upper edge (12) and a lower edge (11), The unpackaged impeller (4) comprises a lower base plate (16), an upper base plate (17), and at least one impeller blade (18) arranged between the upper base plate (17) and the lower base plate (16); and Wherein, in the direction of the drive axis (7), the distance between the outer edge (17a) of the upper base plate (17) and the outer edge (16a) of the lower base plate (16) is smaller than the distance between the lower edge (11) of the volute and the upper edge (12) of the volute.

3. The volute module (1) according to claim 1 or 2, wherein: The volute (5) is delimited in the direction of the drive axis (7) by an upper edge (12) and a lower edge (11), and Wherein, the circumference of the upper edge (12) of the volute is greater than the circumference of the lower edge (11) of the volute.

4. The volute module (1) according to any one of claims 2 or 3, wherein: The lower edge (11) delimits a bottom wall (9) of the impeller chamber (3), wherein the bottom wall (9) surrounds an inlet opening (10) for the pump fluid.

5. The volute module (1) according to any one of claims 2 to 4, wherein: In a plane extending perpendicular to the drive axis (7), the distance of the inner surface (14) of the volute facing the impeller chamber (3) from the drive axis (7) increases starting from the entry area of the volute until the volute (1) transitions into the pressure outlet (6) of the volute module (1), wherein, when viewed from the lower edge (11) of the volute to the upper edge (12) of the volute, the partition tongue (15) of the volute separating the entry area of the volute (5) from the pressure outlet (6) of the volute module (1) is inclined away from the drive axis (7).

6. The volute module (1) according to any one of the preceding claims, wherein The volute module (1) is configured so that, when the volute module (1) is used as part of the multi-stage centrifugal pump (19), a rotating flow of pump fluid generated by the unencapsulated impeller (4) flows away from the unencapsulated impeller (4) toward an inner surface (25) of the impeller chamber (3), where the rotating flow of pump fluid is directed toward the volute (5).

7. The volute module (1) according to any one of the preceding claims, wherein The volute module (1) comprises a chamber support (27), wherein an inner surface (25) of the impeller chamber (3) facing the drive axis (7) partially surrounds the impeller chamber (3), and wherein the chamber support (27) is configured to direct the rotational flow of the pump fluid generated by the unencapsulated impeller (4) towards the volute (5).

8. The volute module (1) according to claim 7, wherein: When the volute module (1) is used as part of a multi-stage centrifugal pump (19), the volute module (1) is configured so that the rotational flow of the pump fluid generated by the unencapsulated impeller (4) is guided by the chamber support (27) to flow between the outer surface (24) of the initial stage impeller housing (21) and the inner surface (25) of the impeller chamber (3) toward the volute (5).

9. The volute module (1) according to claim 7 or 8, wherein: The chamber support (27) includes at least one end guide vane (29) for directing the rotational flow of the pump fluid generated by the unencapsulated impeller (4) toward the volute (5).

10. The volute module (1) according to any one of the preceding claims, wherein The volute module (1) comprises at least one end guide vane (29) for redirecting the rotational flow of the pump fluid generated by the unencapsulated impeller (4) towards the volute (5).

11. The volute module (1) according to claims 7 and 10, wherein: The at least one end guide vane (29) is part of the chamber support (27).

12. A single-stage centrifugal pump (2) comprising a volute module (1) according to any one of the preceding claims and a motor housing attached to the volute module (1), wherein: The volute module (1) includes the unpackaged impeller (4) but does not include an initial stage impeller casing (21) and an intermediate stage impeller casing.

13. A multi-stage centrifugal pump (19), comprising a volute module (1) according to any one of claims 1 to 11 and a motor housing, wherein: The volute module (1) comprises the unpackaged impeller (4) and the initial stage impeller housing (21), The volute module (1) further comprises one or more intermediate-stage impeller housings, wherein each intermediate-stage impeller housing encloses an impeller rotatable about the drive axis (7) and comprises guide vanes which direct the flow of pump fluid from the impeller of the corresponding intermediate-stage impeller housing to the impeller of a subsequent stage of the multi-stage pump, wherein the subsequent stage of the multi-stage pump is formed by the unenclosed impeller (4) or by another intermediate-stage impeller housing.

Images