Patent Application
20250035118
The present application is based upon and claims the right of priority to Belgian Patent Application No. 2023/5609, filed on Jul. 25, 2023, the disclosure of which is hereby incorporated by reference herein in its entirety for all purposes.
The invention relates to a vertical turbine pump with a riser pipe extending along an axis, a motor shaft arranged in the riser pipe, an elbow housing with an elbow arranged therein and connected on a pressure side to the riser pipe, a lantern housing arranged on the elbow housing and accommodating the motor shaft, and a motor arranged on the lantern housing and driving the motor shaft. The invention also relates to a method for producing an elbow housing for an elbow which may be arranged therein and connected on a pressure side to a riser pipe and/or a lantern housing for accommodating a motor shaft of a vertical turbine pump driveable by a motor, with the riser pipe extending along an axis and the motor shaft arranged in the riser pipe.
Vertical turbine pumps, also known as vertical turbines, are semi-axial pumps intended to pump liquids, particularly from open liquid reservoirs, to a higher level. Vertical turbine pumps are used in all types of applications, from pumping process water in industrial plants to supplying cooling towers in power stations, from pumping raw water for irrigation to increasing water pressure in municipal pumping systems and for virtually any other conceivable pumping application. Vertical turbine pumps may achieve delivery heads of, for example, 40 to 100 metres by connecting several impellers in series.
Vertical turbine pumps generally comprise a motor mounted on some type of base or motor mount. A motor shaft may either be attached directly to the motor or coupled to it, and extends downwards towards the impeller through a column support or vertical pipe arrangement, also known as a riser pipe. The impeller routinely contains a plurality of impeller blades that rotate with the motor and the motor shaft, thus conveying the fluid into the riser pipe.
EP 2606238 A1 describes a vertical turbine pump, which is elongated in a longitudinal direction, with a motor and a motor shaft which is rotatably coupled to the motor and which drives an impeller. The fluid conveyed vertically upwards by the impeller into a riser pipe exits the riser pipe above a base plate through a tubular elbow in a horizontal direction.
In the embodiments known from the prior art, the elbow is provided in a cast-iron elbow housing, known as a ‘delivery bend’, which is arranged on the base plate in an axial extension of the riser pipe. A cast-iron lantern housing, also known as a motor support or, in combination with the delivery bend, as a DBMS housing, is provided on the elbow housing in an axial extension of the riser pipe, in which the motor shaft is arranged. Lastly, the motor, which is often very heavy, is provided axially on the lantern housing.
In this respect, in the case of the axially elongated DBMS housings known from the prior art, there is a considerable risk that the speed of the motor reaches the natural frequency of the aforementioned components and thus causes resonance, which may lead to vibrations and possible damage to the vertical turbine pumps.
Based on this situation, it is an object of the present invention to specify a vertical turbine pump and a corresponding production method for a vertical turbine pump in which the situation of resonance is avoided.
The object of the invention is achieved by the features of the independent claims. Advantageous embodiments are given in the dependent claims.
Accordingly, the object is achieved by a vertical turbine pump having
In the case of elbow housings and/or lantern housings known from the prior art, there is a not insignificant risk that the natural frequency of this structure may be affected during turbine pump operation in the event of an interaction between the rigidity of a structure formed by the elbow housing and/or the lantern housing and the mass of the engine, resulting in an undesirable situation of resonance that negatively affects the operation of the vertical turbine pump. This risk fundamentally results from the fact that the elbow housings and/or lantern housings known from the prior art do not have a rectangular structure but a round structure, which generally has a lower natural frequency than a rectangular structure.
In other words, the elbow housings and/or lantern housings known from the prior art, with a regular conical or round shape as a cast and/or welded construction with a minimum wall thickness due to the casting process and casting material used, allow only very limited control over material properties and little or no possibility of influencing the rigidity of the structure in order to shift the natural frequency into a range that is not critical for the operation of the vertical turbine pump.
The proposed solution takes a fundamentally different approach to the solutions known from the prior art, in which the elbow housing and/or the lantern housing is, on the one hand, formed mould-free, i.e. is made of rolled steel, for example, and, on the other hand, has a rectangle-like cross section, i.e. has a rectangular, square and/or box-shaped form, for example. The structure created in this way is stiffer than a cast, conical or round shape due to a higher modulus of elasticity, allows greater freedom of design, is more cost-effective, as standard or common steel profiles may be used to achieve the rectangular, square and/or box-shaped form, and also allows a more compact design, as a base of the elbow housing and/or the lantern housing is smaller and the elbow housing and/or the lantern housing may therefore be installed in more confined installation locations.
In summary, the proposed solution enables cost savings through weight reduction and the use of standard components without expensive casting tools, and, since the mechanical properties of rolled steel, for example, are significantly better than those of grey cast iron, an increase in the stiffness of the elbow housing and/or the lantern housing. By optimising the stiffness of the elbow housing and/or the lantern housing in this way, a significant shift in the natural frequency of the vertical turbine pump is achieved due to the use of thrust fields, which significantly reduces vibrations during operation and, as a result, potential destruction of the vertical turbine pump may be ruled out in principle.
To be formed mould-free means, in particular, that the elbow housing and/or the lantern housing is not primary moulded, i.e. in particular is not produced by means of a casting process, i.e. an initial mould of the elbow housing and/or the lantern housing is not produced directly from a liquid state, for example by means of a casting mould. In particular, being formed mould-free also means that the elbow housing and/or the lantern housing is not produced according to a production process in accordance with DIN 8580, i.e. not according to a production process in which a solid body with a geometrically defined shape is produced from a shapeless material. In other words, the expression “mould-free” means in particular that the direct starting materials for shaping the elbow housing and/or the lantern housing are not present in a liquid, gaseous, plastic, granular or powdery state. Preferably, the elbow housing and/or the lantern housing have a rectangular, square and/or aforementioned box-like shape, which defines the rectangular cross section in relation to the axis of the riser pipe. Unless otherwise defined, the terms axial and radial preferably refer to the axis of the riser pipe. The cross section preferably extends along the radial direction and/or the normal of the cross section runs parallel to the axis.
In particular, the elbow housing and/or the lantern housing provides a load-bearing function for the hydraulics and/or motor of the turbine pump, serves to guide the motor shaft, facilitates maintenance, etc. The stiffer and more robust the elbow housing and/or the lantern housing, the better that any vibrations occurring during operation of the turbine pump may be damped. Compared to a round or cylindrical structure, the proposed rectangular structure is stiffer and therefore less prone to vibration. The occurrence of resonance means in particular a shift of the first and second natural modes, which may coincide with an operating frequency of the turbine pump.
Vertical turbine pumps are semi-axial pumps configured to pump liquids, particularly from open liquid reservoirs, to a higher level. Vertical turbine pumps are often multi-stage, i.e. equipped with more than one impeller. However, they may also be single-stage, i.e. equipped with only one impeller. Each additional impeller increases the delivery head that the pump may generate at a constant flow rate. The outer diameter of the riser pipe may be as small as a few centimetres, so that the vertical turbine pump is 20 often much longer axially along the axis than it is radially wide. The riser pipe regularly extends largely below a base plate to which the vertical turbine pump may be attached. In this respect, the motor and the elbow are preferably arranged above the base plate in such a way that the riser pipe is connected just above or at the base plate, in particular fluid-tightly, to a first end of the elbow and the motor is arranged vertically above the elbow. The riser pipe is preferably made of metal and/or has a circular or circular-like cross section.
The motor shaft preferably extends in an axial direction along the centre line of the riser pipe and passes through the tubular elbow on an outer side in an axial extension of the riser pipe. On this outer side, an opening may be provided in the elbow through which the motor shaft passes. Preferably, a seal, in particular a radial seal, is provided, which is arranged in the opening and seals the motor shaft fluid-tightly in a radial circumferential manner with respect to the elbow. Preferably, the motor shaft ends in the lantern housing, in which a coupling may be arranged which may be connected between the motor and the motor shaft.
The elbow is preferably configured as a pipe bend or in pipe-bend-like manner and/or has a circular or elliptical shape when viewed from the side. The elbow preferably extends over an arc of a circle or an in a circular-arc-like manner over 90°, although other values such as 80° or 100° are also possible. Preferably, the elbow has a continuous curvature away from the axis, which in particular does not mean that the elbow initially extends in a direction opposite a second end of the elbow facing away from the riser pipe, for example has an S-shaped form, but instead extends linearly and/or continuously, in particular in a circular-arc-like or elliptical manner in side view, continuously further away from the axis or the riser pipe with respect to its radial centre line. Furthermore, the feature that the elbow has a curvature continuously away from the axis is to be understood in particular synonymously with the feature that the elbow extends continuously away from the axis with respect to its radial, in particular circular-arc-like, centre line. In the case of an elliptical shape extending in particular over 90°, the secondary axis of the ellipse preferably runs parallel to the axis and/or the main axis runs horizontally.
Preferably, a radial diameter relative to an axis of the elbow initially decreases as the height of the elbow from the first elbow end to the second elbow end and then increases, which means in particular that, at at least one position between the first elbow end and the second elbow end, the height of the elbow is less than the height at the first elbow end and/or at the second elbow end. In a side view, the elbow has a particularly ‘flattened’ shape. In particular, the elbow may again have a ‘dented’ shape on its outside when viewed from the side, wherein the height at the ‘dent’ is in particular reduced to a maximum. The radial diameter is understood in particular to be a radial inner diameter of the elbow in relation to the axis of the elbow, which defines a clear height in the elbow through which the fluid may flow. In this respect, when talking about a reduction or enlargement of the diameter, the outer diameter may also be meant in addition to the inner diameter.
According to a preferred further development, the elbow housing and/or the lantern housing is formed mould-free, in particular made of rolled steel, sheet metal and/or welded. For example, the elbow housing and/or the lantern housing may have four axially extending flat side walls, for example steel sheets, which are each welded with their opposite axial edges to an upper and lower, radially extending and in particular rectangular fastening plate with an opening. The elbow housing and/or the lantern housing is made in particular of metal, such as iron or aluminium. Welding allows particularly thin walls to be realised, which are around two to three times thinner than a cast construction. The elbow housing and the lantern housing may be formed in one piece as a single or common housing, i.e. not divided into two housings.
According to a further preferred embodiment, the elbow housing and/or the lantern housing has rolled, corner and/or angle profiles extending axially at its corners, in particular L-profiles, in particular triangular profiles in cross section, in particular as L-profiles closed with a diagonal sheet. A different type of angle profile may also be selected, depending on the desired rigidity behaviour of the angle profile. Axially and/or longitudinally extending corner and/or angle profiles may be used to transmit longitudinal forces that counteract bending moments. The angle profile is preferably configured as a straight, axially extending, extruded and/or thin-walled profile, for example as a tubular or channel profile, which may be welded to a flat steel sheet as a side wall without complex edge preparation for ease of manufacture. If, for example, an additional stiffening profile is required during operation of the vertical turbine pump in order to further increase rigidity, such an additional stiffening profile may simply be welded onto the mould-free elbow housing and/or lantern housing, in contrast to elbow housings and/or lantern housings known from the prior art with conically or cylindrically shaped and cast side walls. The angle profiles are preferably directed outwards, i.e. the legs of the angle profiles extend radially away from the axis in order to increase the shear and bending stiffness. L-profiles closed with a diagonal sheet provide high rigidity and are easy to produce.
According to another preferred development, the elbow housing and/or the lantern housing has at least two opposing, axially extending flat side walls. Such flat, in particular spaced-apart, rectangular and/or mutually parallel side walls allow a shear resistance to be utilised in order to effectively damp unwanted vibrations. The side walls may be arranged between two angle profiles provided at the corners and, in particular, welded to these and/or may extend over the entire axial extent of the angle profiles and/or between the fastening plates. In this way, the rigidity may be further increased, as the side walls serve as a so-called shear profile. In particular, a box-shaped elbow housing and/or lantern housing, preferably without curvatures, allows a high degree of rigidity.
According to a further preferred embodiment, a flat stiffening element extending axially and radially extends away from the side wall. The stiffening element may be profiled, rectangular and/or flat, in particular extending orthogonally away from the side wall and/or welded to it, and allows the natural frequency to be influenced favourably. Preferably, the stiffening element extends along the entire axial extent of the side wall, the angle profile, the elbow housing and/or the lantern housing and/or is connected to the fastening plates, in particular welded to them.
According to another preferred development, an opening is provided in the side wall. The opening may be configured as a recess in the side wall, so that the side wall extends, for example, only over part of the axial extent of the lantern housing and/or the lantern housing. The opening may be closed with a ventilation grille or the like and/or may be used for maintenance of the lantern housing and/or the lantern housing.
According to a further preferred embodiment, the elbow housing and the lantern housing and/or the lantern housing and the motor, in particular a motor housing of the motor, are screwed together, in particular screwed together at regular intervals and/or at the corners.
According to another preferred development, the elbow housing and/or the lantern housing has, at at least one axial end, in particular at both axial ends, a radially extending fastening plate, in particular in the form of a rectangular flange, in particular with a rectangular cross section.
Preferably, the elbow housing and the lantern housing and/or the lantern housing and the motor, in particular the motor housing of the motor, are connected to each other with screws passed through the respective fastening plates. A rectangular and/or mould-free base element is preferably provided, which also preferably has a respective radially extending fastening plate, in particular with a rectangular cross section, at both axial ends. The base element is preferably provided between the elbow housing and a base plate, preferably a base, wherein the base element is further preferably screwed to the elbow housing and/or the base plate by the respective fastening plate. The fastening plate preferably has a, in particular, rectangular or round opening through which, for example, the motor shaft is guided.
According to a further preferred embodiment, the elbow housing, the lantern housing and/or the motor is arranged in an axial extension of the riser pipe and/or the lantern housing is arranged in an axial extension of the riser pipe between the elbow housing and the motor. In other words, the motor is preferably arranged above the lantern housing and the lantern housing is preferably arranged above the elbow housing. According to another preferred development, the elbow housing and/or the lantern housing is box-shaped, in particular rectangular.
According to a further preferred embodiment, the vertical turbine pump has an impeller arranged at an opposite, lower end of the riser pipe and driven by the motor shaft for conveying a fluid into the riser pipe. The riser pipe and/or the vertical turbine pump preferably has an axial length of ≥10, 20, 30, 40 m or more. A plurality of impellers arranged axially one behind the other may be provided at the lower first end of the riser pipe, through which the fluid is conveyed into the riser pipe and axially upwards to the elbow. A second riser pipe end is preferably connected to the first elbow end fluid-tightly, in particular they are screwed together.
The problem is further solved by a method for producing an elbow housing for an elbow arrangeable therein and connectable on a pressure side to a riser pipe and/or for producing a lantern housing for accommodating a motor shaft of a vertical turbine pump driveable by a motor, with the riser pipe extending along an axis and the motor shaft arranged in the riser pipe, said method having the step of:
forming, in particular producing, the elbow housing and/or the lantern housing mould-free with a rectangular cross section.
According to a preferred embodiment, mould-free forming comprises producing from rolled steel, from sheet metal and/or by means of welding.
According to another preferred development, mould-free forming comprises welding of axially extending angle profiles, in particular L-profiles, in particular profiles of triangular cross section, provided at corners of the elbow housing and/or the lantern housing, to a radially extending fastening plate, in particular with a rectangular cross section, provided at at least one axial end, in particular at both axial ends, of the elbow housing and/or the lantern housing.
According to a further preferred embodiment, mould-free forming comprises providing at least two opposing, axially extending flat side walls.
According to another preferred development, mould-free forming comprises forming of the elbow housing and/or the lantern housing in a box shape.
Further advantages and embodiments of the method will become apparent to a person skilled in the art in analogy to the vertical turbine pump described above.
In the following, the invention is explained in greater detail with reference to the appended drawings with reference to preferred exemplary embodiments.
In the drawings
The vertical turbine pump 1 has a riser pipe 5 extending along an axis 4 with a circular outer cross section, which has a plurality of interconnected segments. A motor shaft 6 extends in the centre of the metal riser pipe 5 along the axis 4 and along the entire length of the riser pipe 5 in such a way that a free space is formed radially around the motor shaft 6 between the latter and the riser pipe 5, through which free space the fluid conveyed by the vertical turbine pump 1 rises axially upwards. For this purpose, several impellers 8 arranged axially one above the other are provided at a lower riser pipe end 7 and are driven by the motor shaft 6, draw in the fluid, and convey it into the free space.
The upper end 9 of the riser pipe 5 is attached to a base plate 10, so that the riser pipe 5 extends vertically downwards away from the base plate 10. Above the base plate 10, the elbow housing 2 adjoins vertically or upwards in the direction of the axis 4, initially in contact with the base plate, and in turn is adjoined by the lantern housing 11 in axial contact, and lastly by a motor 12 driving the motor shaft 6 and provided in a motor housing. A coupling 13 is arranged in the lantern housing 11 and is connected between the motor 12 and the motor shaft 6. Accordingly, the motor shaft 6 ends in the lantern housing 11. The elbow housing 2 and the lantern housing 11 are configured in two parts and are screwed together, as described below. The riser pipe upper end 9 is connected fluid-tightly to a first elbow end of the elbow 3 facing the impeller 8.
Referring now to
Specifically, the elbow housing 2 and the lantern housing 11 each have four corners of axially extending, spaced-apart angle profiles 14 at their corners, which are configured as outwardly open L-profiles and are each closed, i.e. triangular in cross section, as may be seen in particular from
The four side walls 15 extend, at least on the lantern housing 11, only along one part of the axial extent of the angle profiles 14, wherein an opening 16 is provided in the other part for maintenance of the lantern housing 11, which opening 16 is covered by a removable grille. The elbow housing 2 also has four side walls 15, wherein one side wall is closed insofar as the elbow 3 passes through this side wall 15 shown in the front left of the figure. In the embodiment shown in
Returning to
Axially below the elbow housing 2, a base element 19 is provided which is also formed mould-free and in a box shape, and which also has a fastening plate 18 at its lower axial ends. At its upper axial end, the base element 19 is formed and arranged congruently with and in contact with the lower fastening plate 18 of the elbow housing 2. Like the lantern housing 11 of
The base element 19 is fastened to a base with its fastening plate 18, not shown. The elbow housing 2 placed axially on the base element 19 is fastened to the base element 19 with screws guided through the lower fastening plate 18 of the elbow housing 2, wherein the screws are provided at regular intervals on the one hand and at the corners of the fastening plate 18 on the other. The lantern housing 11 placed axially on the elbow housing 2 is also fastened by screws guided through the respective fastening plates 18, wherein the screws again are provided at regular intervals on the one hand and at the corners of the fastening plate 18 on the other. Lastly, the motor housing of the motor 12, which is mounted axially on the lantern housing 11, is also connected by screws guided through the octagonal fastening plate 18 of the lantern housing 11 and the circular base of the motor housing.
The described exemplary embodiments are merely examples that may be modified and/or supplemented in a variety of ways within the scope of the claims. Each feature described for a particular exemplary embodiment may be used independently or in combination with other features in any other exemplary embodiment. Each feature described for an exemplary embodiment of a certain category may also be used in a corresponding manner in an exemplary embodiment of another category.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023/5609 | Jul 2023 | BE | national |
