FI127130B - Water transfer pump for purification of watercourses - Google Patents

Description

A water transfer pump for water system purification Field of the invention

The invention relates generally to water system purification. More particularly, the invention relates to a water transfer pump for water system purification.

Background

Lakes and coastal areas of seas comprise typically water areas where natural water circulation or water changing is not sufficient and/or where especially basin areas suffer from a lack of oxygen and therefore a significant amount of phosphorous can be released from bottom sediments. The water quality of water areas of the kind mentioned above is vulnerable to even a small amount of eutrophic loading, and as a corollary there is an increased risk of algae growth especially during a later half of summer. The water quality can be improved by transferring fresh water to these areas and/or by causing a vertical water circulation between the surface and the bottom region in order to oxygenize the water. The water change and/or the vertical water circulation between the bottom and the surface improve the water quality relatively quickly.

Water purification based on the water change and/or the vertical water circulation is however not free from challenges. One of the challenges is related to energy consumption of water transfer pumps used for maintaining the water change and/or the vertical water circulation. Typical pumps such as e.g. standard centrifugal pumps have a poor energy-efficiency in situations where there is a need to transfer a big volume of water but, on the other hand, the pump head is low. As obvious, it is not reasonable to practice water environmental renovation in an energy wasting way.

Publication WO2011052838 describes a device for purifying lakes. The device comprises a plurality of water wheels for aerating the surface of a lake. The water wheels are configured to rotate with their bottom parts submerged to a predetermined depth in the lake water. The device further comprises a plurality of ejector pumps for circulating water. The ejector pumps are respectively provided in the water surrounding the plurality of water wheels. The device comprises a free electron and radical generating device for expelling free electrons and radicals at the water-discharging ports of the plurality of ejector pumps, thereby subjecting contaminant substances contained in the water expelled at the water-discharging ports of the plurality of ejector pumps to an oxygenizing treatment. One challenge of the above-described device is a need for sufficiently firm foundations or other arrangements for keeping the water wheels in correct positions when being submerged in the lake water.

Summary

The following presents a simplified summary in order to provide a basic understanding of some embodiments of the invention. The summary is not an extensive overview of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of exemplifying embodiments of the invention.

In accordance with the invention, there is provided a new water transfer pump for purifying a lake, a coastal area of a sea, or some other water system. A water transfer pump according to the invention comprises: - a tubular flow channel, - a propeller rotor having an axis of rotation parallel with a spatial center line of the of the tubular flow channel and comprising a plurality of rotor blades for pumping water to flow through the tubular flow channel, and - an electrical motor suitable for underwater use and connected to the propeller rotor and mechanically supported with radially directed bearer arms to the walls of the tubular flow channel, wherein the tubular flow channel comprises a rigid portion for mechanically supporting the electrical motor and a sleeve made of flexible and bendable material, the rigid portion and the sleeve being connected to each other successively in an axial direction of the tubular flow channel, and the sleeve being capable of having a tubular shape with the aid of water pressure produced by the propeller rotor.

The above-described water transfer pump which is an axial pump is more energy-efficient than for example traditional centrifugal pumps for such cases where there is a need to transfer a big volume of water but, on the other hand, the pump head is low. Furthermore, the tubular flow channel does not need such foundations or other mechanical support arrangements which are needed for keeping the water wheels of the device described in WO2011052838 in correct positions. Instead, the tubular flow channel can be kept at a desired place and position with relatively simple anchoring and/or float element arrangements.

The ability to transfer a big volume of water with a good energy-efficiency can be achieved by using a propeller rotor which has a sufficiently big diameter so as to keep the axial speed of the water flow sufficiently low. Rotor blades are advantageously designed so that the ratio of the ascending force coefficient, i.e. the lift coefficient, to the drag coefficient is as big as possible, and the circumferential speed of the tips of the rotor blades is advantageously selected so that a sufficient cavitation margin is maintained. Furthermore, the blade profile loading is advantageously selected so that the width of the rotor blades can be low with respect to the length of the rotor blades so that the rotor blades are cost effective to manufacture and free space between the rotor blades enable fish to go through the water transfer pump. The radially directed bearer arms supporting the electrical motor are advantageously shaped to constitute outlet vanes for reducing curling movement caused by the rotor blades to the water which flows through the tubular flow channel so as to improve the energy-efficiency. In a water transfer pump according to an advantageous and non-limiting embodiment of the invention, the efficiency of the blading system constituted by the rotor blades and the outlet vanes can be as high as about 90%. The outlet part of the tubular flow channel constituting an outlet diffuser is advantageously shaped to minimize flow losses. Furthermore, the electrical motor is advantageously covered with a casing shaped to minimize the flow losses. The propeller rotor is advantageously provided with a blade angle control so as to enable minimization of energy consumption at each desired operating point.

In a water transfer pump according to an exemplifying and non-limiting embodiment of the invention, the electrical motor is a wet motor whose shaft is directly connected to the propeller rotor and which comprises water-lubricated bearings. In the wet motor, the gap between the stator of the electrical motor and the rotor of the electrical motor is filled with water when the water transfer pump is submerged. In this exemplifying case, there is no a need for a shaft seal and no need for lubrication oil. Furthermore, there is no need for a gear. A number of exemplifying and non-limiting embodiments of the invention are described in accompanied dependent claims.

Various exemplifying and non-limiting embodiments of the invention both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying embodiments when read in connection with the accompanying drawings.

The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of "a" or "an", i.e. a singular form, throughout this document does not exclude a plurality.

Brief description of figures

Exemplifying embodiments of the invention and their advantages are explained in greater detail below in the sense of examples and with reference to the accompanying drawings, in which: figure 1a shows a perspective view of a water transfer pump according to an exemplifying and non-limiting embodiment of the invention, figure 1 b shows a section view of the water transfer pump illustrated in figure 1 a, figure 2a illustrates a water transfer pump according to an exemplifying and nonlimiting embodiment of the invention, figure 2b illustrates a water transfer pump according to another exemplifying and non-limiting embodiment of the invention, figure 3 illustrates a water-lubricated wet motor suitable for a water transfer pump according to an exemplifying and non-limiting embodiment of the invention, and figure 4 illustrates another water-lubricated wet motor suitable for a water transfer pump according to an exemplifying and non-limiting embodiment of the invention.

Description of exemplifying embodiments

Figure 1a shows a perspective view of a water transfer pump according to an exemplifying and non-limiting embodiment of the invention, and figure 1b shows a section view of the water transfer pump. The section plane is parallel with the yz-plane of a coordinate system 199. The water transfer pump comprises a tubular flow channel 101 and a propeller rotor 102. The axis of rotation of the propeller rotor is parallel with a spatial center line of the of the tubular flow channel. The axis of rotation of the propeller rotor is parallel with the z-axis of the coordinate system 199. The propeller rotor 102 comprises a plurality of rotor blades for pumping water to flow through the tubular flow channel 101. In the exemplifying water transfer pump illustrated in figures 1a and 1b, a first end 105 of the tubular flow channel is shaped to constitute an elliptic intake portion tapering towards the propeller rotor 102 and a second end 106 of the tubular flow channel is shaped to constitute a conical outlet diffuser. The water transfer pump comprises an electrical motor 103 which is suitable for underwater use and configured to drive to the propeller rotor 102. As illustrated in figure 1b, the electrical motor 103 and thereby also the propeller rotor 102 are mechanically supported with radially directed bearer arms to the walls of the tubular flow channel. Two of the radially directed bearer arms are denoted with a reference number 104 in figure 1b. The radially directed bearer arms are advantageously shaped to constitute outlet vanes for reducing curling movement caused by the rotor blades to the water which flows through the tubular flow channel 101 so as to improve the energy-efficiency of the water transfer pump.

The electrical motor 103 is advantageously a wet motor whose shaft is directly connected to the propeller rotor 102 and which comprises water-lubricated bearings. It is, however, also possible that the electrical motor comprises a shaft seal and a water-tight casing and the water transfer pump comprises a device to introduce overpressure air or some other suitable gas e.g. nitrogen into the water-tight casing so as to prevent water from leaking into the water-tight casing.

In a water transfer pump according to an exemplifying and non-limiting embodiment of the invention, the rotor blades of the propeller rotor 102 are adjustably joined with the hub of the propeller rotor so as to enable adjustment of blade angles. With a proper selection of the blade angles, it is possible to optimize the energy-efficiency of the water transfer pump for a given operating point.

Figure 2a illustrates a water transfer pump according to an exemplifying and nonlimiting embodiment of the invention. The water transfer pump comprises a tubular flow channel 201 and a propeller rotor 202. The axis of rotation of the propeller rotor is parallel with a spatial center line of the of the tubular flow channel. The axis of rotation of the propeller rotor is parallel with the z-axis of the coordinate system 299. The propeller rotor 202 comprises a plurality of rotor blades for pumping water to flow through the tubular flow channel 201. The water transfer pump comprises an electrical motor which is suitable for underwater use and configured to drive the propeller rotor 202. The electrical motor is not shown in figure 2a. The tubular flow channel is provided with a first element 211 that has advantageously a toroid shape and is connected to an end of the tubular flow channel 201. The density of the element 211, i.e. the mass divided by the volume kg/m3, is smaller than the density of water. Thus, the element 211 assists the tubular flow channel 201 to be in a substantially vertical position when the other end of the tubular flow channel 201 is anchored to the bottom as illustrated in figure 2a.

The exemplifying water transfer pump illustrated in figure 2a comprises a pontoon 207, a solar cell panel 208 installed on the pontoon, and electrical equipment for driving the electrical motor with electrical energy produced by the solar cell panel. The electrical equipment may comprise for example a power electronic converter 209 for converting the electrical energy produced by the solar cell panel to a form suitable for the electrical motor and a power cable 210 for transferring the electrical energy to the electrical motor. In a case where the electrical motor is an alternating current “AC” motor, the power electronic converter 209 is a frequency converter.

Figure 2b illustrates a water transfer pump according to another exemplifying and non-limiting embodiment of the invention. In this water transfer pump, the tubular flow channel is provided with a second element 212 that has advantageously a toroid shape and is connected to the end of the tubular flow channel intended to be towards the bottom. The density of the element 212, i.e. the mass divided by the volume kg/m3, is greater than the density of water. Thus, the element 212 assists the tubular flow channel to be in a substantially vertical position when the tubular flow channel is arranged to be suspended from the pontoon 207 as illustrated in figure 2b or from some other object above the tubular flow channel. It also possible that one end of the tubular flow channel is provided with an element, such as the element 211, having density smaller than that of water and the opposite end of the tubular flow channel is provided with another element, such as the element 212, having density greater than that of water.

The exemplifying water transfer pumps illustrated in figures 2a and 2b are suitable for causing vertical water circulation between the surface and the bottom region of a lake, a sea, or some other water system. In order make water to flow through the tubular flow channel 201 downwards or upwards, the pressure difference caused by temperature stratification of the water has to be overcome. This pressure different is typically at most 200 Pa in cases where the depth of the water is less than 20 m. Thus, also in the vertical applications illustrated in figures 2a and 2b, the water transfer pump does not need to produce a significant pressure difference.

The tubular flow channel 201 shown in figures 2a and 2b can be a tube made of rigid material. It is also possible that the tubular flow channel 201 comprises a rigid portion for mechanically supporting the electrical motor and a sleeve made of flexible and bendable material such as e.g. plastic membrane. The rigid portion and the flexible and bendable sleeve are connected to each other successively in the axial direction of the tubular flow channel. The flowing direction of water in the tub ular flow channel 201 is advantageously so that the water flows from the rigid portion to the flexible and bendable sleeve. The flexible and bendable sleeve can be arranged to have its tubular shape with the aid of water pressure produced by the propeller rotor 202. Also in cases where the tubular flow channel comprises the flexible and bendable sleeve, the tubular flow channel can be kept in the desired upright position with the aid of the elements 211 and/or 212 in the way shown in figures 2a and 2b. The flexible and bendable sleeve can be transported within a small room and its weight can be low even if the dimensions of the tubular flow channel 201 were large. Hence, the axial length of the flexible and bendable sleeve is advantageously significantly greater than that of the rigid portion for mechanically supporting the electrical motor. It is also possible that the sleeve is provided with support rings so that the sleeve can be collapsed only in its axial direction.

The axial length L of the tubular flow channel 201 shown in figures 2a and 2b can be for example on the range 3 m - 30 m. More preferably, the axial length L is on the range 5 m - 30 m, yet more preferably, the axial length L is on the range 5 m-20 m. The diameter D of the tubular flow channel 201 shown in figures 2a and 2b can be for example on the range 0.5 m - 6 m. More preferably, the diameter D is on the range 1 m - 6 m, yet more preferably, the diameter D is on the range 1 m -3 m.

Figure 3 illustrates an electrical motor 303 that is a water-lubricated wet motor suitable for water transfer pumps according to exemplifying and non-limiting embodiments of the invention. Water lubricated bearings of the electrical motor are denoted with reference number 314 in figure 3. The electrical motor 303 is an axial flux permanent magnet motor where the magnetic flux passes an axially directed gap between electromagnetically active parts 323 of a stator and electromagneti-cally active parts of a rotor 315 in directions substantially parallel with the z-axis of a coordinate system 399. The electromagnetically active parts of the rotor 315 are encapsulated within a hermetic casing which consists of a plate 319 and a dome 320 which are hermetically joined together. The hermetic casing can be made of for example stainless steel and, in this case, the plate 319 and the dome 320 can be welded together. Also a shaft 325 can be made of stainless steel, and the shaft can be attached to the hermetic casing by welding so that there are hermetic joints between the shaft and hermetic casing. Rotor blades can be attached to the hermetic casing. Two of the rotor blades are denoted with a reference number 322 in figure 3. The electromagnetically active parts of the rotor comprise permanent magnets and a rotor yoke 318. Two of the permanent magnets are denoted with a reference number 316 in figure 3. Furthermore, the encapsulated part of the rotor comprises support material 321 which can be for example aluminum. It is worth noting that the electric welding can be used for welding the plate 319 and the dome 320 together because the welding joint is located so that the magnetic field produced by the permanent magnets does not disturb the welding arc. The rotor yoke 318 may comprise for example a strip of electrical steel sheet wrapped into a spiral form so as to constitute a toroid. It is also possible that the rotor yoke 318 is made of solid, i.e. non-layered, ferromagnetic material whose electrical resistivity is sufficiently high, e.g. cast iron.

Figure 4 illustrates an electrical motor 403 that is a water-lubricated wet motor suitable for water transfer pumps according to exemplifying and non-limiting embodiments of the invention. The electrical motor 403 is a radial flux permanent magnet motor where the magnetic flux passes a radially directed gap between electromagnetically active parts 423 of a stator 413 and electromagnetically active parts of a rotor 415 in directions substantially perpendicular to the z-axis of a coordinate system 499. As illustrated in figure 4, the stator 413 of the electrical motor 403 is shaped to comprise a circumferential groove and the rotor 415 of the electrical motor is located in the groove. The axially facing surfaces of the groove are configured to operate as bearing surfaces of water-lubricated axial bearings. The radially facing surface of the groove is configured to operate not only as a surface through which the magnetic flux passes between the stator and the rotor but also as a bearing surface of a water-lubricated radial bearing. The motor comprises a water pump 424 for feeding water to the surfaces of the groove via a channel system so as to provide a lubricating water film between the rotor and the stator. In figure 4, one of the channels of the channel system is denoted with a reference number 430. The water pump may comprise for example a wet motor which has hydrodynamic water bearings.

The rotor 415 of the electrical motor 403 comprises a body portion made of for example fiberglass where permanent magnets and possibly also a ferromagnetic yoke are installed. In figure 4, one of the permanent magnets is denoted with a reference number 416. Rotor blades can be attached to the body portion of the rotor. It is also possible that the rotor blades and the body portion of the rotor constitute a single piece of material. In figure 4, two of the rotor blades are denoted with a reference number 422.

The stator 413 of the electrical motor 403 comprises a body portion which can be made of for example concrete. The electromagnetically active parts 423 of the stator, i.e. the stator windings and the ferromagnetic stator core, are attached to the body portion. The stator winding can be made of for example polyvinyl chloride “PVC” insulated copper conductor. Especially in cases where the frequency of stator currents is low, the stator core can be made of ferromagnetic stainless steel so as to avoid materials which are vulnerable to corrosion. The electromagnetically active parts 423 of the stator are advantageously impregnated and coated with suitable material, e.g. resin, so as to provide a hermetic structure.

The axially facing surfaces of the groove which operate as bearing surfaces of the water-lubricated axial bearings can be implemented with for example metal rings which are cast in the concrete so that surfaces of the metal rings constitute the axially facing surfaces of the groove. The radially facing surface of the groove which operates as a bearing surface of the radial bearing can be implemented with material which has sufficiently high electrical resistivity so as to allow the alternating magnetic flux to pass between the stator and the rotor. The radially facing surface of the groove can be implemented for example with carbon fiber reinforced resin.

Figure 4 shows also a section view of a part of a tubular flow channel 401 and two radially directed bearer arms 404 which support the electrical motor 403 to the walls of the tubular flow channel 401. The tubular flow channel and the radially directed bearer arms can be made of concrete, and together with the body portion of the stator they may constitute a single piece of material. The radially directed bearer arms are advantageously shaped to constitute outlet vanes for reducing curling movement caused by the rotor blades to the water which flows through the tubular flow channel 401.

The specific examples provided in the description given above should not be construed as limiting. Therefore, the invention is not limited merely to the embodiments described above.

Claims (11)

What is claimed is:

1. Vedensiirtopumppu vesistön puhdistamiseksi, joka pumppu käsittää: - putkimaisen virtauskanavan (101,201), - potkuriroottorin (102, 202), jonka pyörimisakseli on yhdensuuntainen putkimaisen virtauskanavan spatiaalisen keskiviivan kanssa ja joka käsittää joukon roottorinlapoja veden pumppaamiseksi virtaamaan putkimaisen virtaus-kanavan läpi, ja - sähkömoottorin (103), joka on kytketty potkuriroottoriin ja mekaanisesti tuettu radiaalisesti suunnatuilla kannatinvarsilla (104) putkimaisen virtauskanavan seinämiin, jolloin sähkömoottori on konfiguroitu sopivaksi vedenalaiseen käyttöön, tunnettu siitä, että putkimainen virtauskanava (201) käsittää jäykän osuuden sähkömoottorin tukemiseksi mekaanisesti ja joustavasta ja taivutettavasta materiaalista tehdyn letkuosuuden, missä jäykkä osuus ja letkuosuus ovat yhdistetyt toisiinsa peräkkäisesti putkimaisen virtauskanavan aksiaalisessa suunnassa ja letkuosuus kykenee asettumaan putkimaiseen muotoon potkuriroottorin (202) tuottaman vedenpaineen avulla.

1. A water transfer pump for water system purification, the pump comprising: - a tubular flow channel (101,201), - a propeller rotor (102, 202) having an axis of rotation parallel with a spatial center line of the of the tubular flow channel and comprising a plurality of rotor blades for pumping water to flow through the tubular flow channel, and - an electrical motor (103) connected to the propeller rotor and mechanically supported with radially directed bearer arms (104) to walls of the tubular flow channel, the electrical motor being configured to be suitable for underwater use, characterized in that the tubular flow channel (201) comprises a rigid portion for mechanically supporting the electrical motor and a sleeve made of flexible and bendable material, the rigid portion and the sleeve being connected to each other successively in an axial direction of the tubular flow channel, and the sleeve being capable of having a tubular shape with the aid of water pressure produced by the propeller rotor (202).

2. Patenttivaatimuksen 1 mukainen vedensiirtopumppu, jossa sähkömoottori käsittää vesivoidellut laakerit ja sähkömoottorinstaattorin ja sähkömoottorin roottorin välinen rako on täynnä vettä silloin kun vedensiirtopumppu on upotettuna.

2. A water transfer pump according to claim 1, wherein the electrical motor comprises water-lubricated bearings and a gap between a stator of the electrical motor and a rotor of the electrical motor is filled with water when the water transfer pump is submerged.

3. Patenttivaatimuksen 1 mukainen vedensiirtopumppu, jossa sähkömoottori käsittää akselitiivisteen ja vesitiiviin kotelon ja vedensiirtopumppu käsittää laitteen ylipainekaasun toimittamiseksi vesitiiviiseen koteloon veden estämiseksi vuotamasta vesitiiviin kotelon sisään.

3. A water transfer pump according to claim 1, wherein the electrical motor comprises a shaft seal and a water-tight casing and the water transfer pump comprises a device to introduce overpressure gas into the water-tight casing so as to prevent water from leaking into the water-tight casing.

4. Jonkin patenttivaatimuksen 1-3 mukainen vedensiirtopumppu, jossa radiaalisesti suunnatut kannatinvarret (104) on muotoiltu muodostamaan poistosiivet root-torinlapojen putkimaisen virtauskanavan läpi virtaavaan veteen aiheuttaman pyör-teilyliikkeen vähentämiseksi.

4. A water transfer pump according to any of claims 1 -3, wherein the radially directed bearer arms (104) are shaped to constitute outlet vanes for reducing curling movement caused by the rotor blades to the water flowing through the tubular flow channel.

5. Jonkin patenttivaatimuksen 1-4 mukainen vedensiirtopumppu, jossa putkimaisen virtauskanavan ensimmäinen pää (105) on muotoiltu muodostamaan pot-kuriroottoria kohti suppeneva elliptinen imuosa ja putkimaisen virtauskanavan toinen pää (106) on muotoiltu muodostamaan kartiomainen poistodiffuusori.

5. A water transfer pump according to any of claims 1-4, wherein a first end (105) of the tubular flow channel is shaped to constitute an elliptic intake portion tapering towards the propeller rotor and a second end (106) of the tubular flow channel is shaped to constitute a conical outlet diffuser.

6. Jonkin patenttivaatimuksen 1-5 mukainen vedensiirtopumppu, jossa sähkö-moottori on aksiaalivuotyyppinen kestomagneettimoottori (303) ja sähkömoottorin roottorin (315) sähkömagneettisesti aktiiviset osat on kapseloitu hermeettisen kotelon (319, 320) sisälle.

6. A water transfer pump according to any of claims 1-5, wherein the electrical motor is an axial flux permanent magnet motor (303) and electromagnetically active parts of a rotor (315) of the electrical motor are encapsulated within a hermetic casing (319, 320).

7. Jonkin patenttivaatimuksen 1-5 mukainen vedensiirtopumppu, jossa sähkö-moottorin (403) staattori (413) on muotoiltu käsittämään kehän suuntainen ura ja sähkömoottorin roottori (415) on sijoitettu ainakin osittain kyseiseen uraan ja uran pinnat on konfiguroitu toimimaan vesivoideltujen laakerien kantopintoina sähkö-moottorin roottorin tukemiseksi sähkömoottorin staattoriin nähden aksiaalisissa ja radiaalisissa suunnissa.

7. A water transfer pump according to any of claims 1-5, wherein a stator (413) of the electrical motor (403) is shaped to comprise a circumferential groove and a rotor (415) of the electrical motor is at least partially located in the groove, and surfaces of the groove are configured to operate as bearing surfaces of water-lubricated bearings so as to support the rotor of the electrical motor with respect to the stator of the electrical motor in axial and radial directions.

8. Jonkin patenttivaatimuksen 1-7 mukainen vedensiirtopumppu, jossa potkuri-roottorin (102) roottorinlavat on säädettävästi liitetty potkuriroottorin napaan lapa-kulmien säätämisen mahdollistamiseksi.

8. A water transfer pump according to any of claims 1-7, wherein the rotor blades of the propeller rotor (102) are adjustably joined with a hub of the propeller rotor so as to enable adjustment of blade angles.

9. Jonkin patenttivaatimuksen 1-8 mukainen vedensiirtopumppu, jossa putkimainen virtauskanava on varustettu vähintään yhdellä seuraavista putkimaisen virtauskanavan avittamiseksi olemaan olennaisesti pystysuuntaisessa asennossa upotettuna ollessaan: ensimmäisellä elementillä (211), joka on yhdistetty putkimaisen virtauskanavan (201) toiseen päähän ja jonka tiheys on pienempi kuin veden tiheys, toisella elementillä (212), joka on yhdistetty putkimaisen virtauskanavan toiseen päähän ja jonka tiheys on suurempi kuin veden tiheys.

9. A water transfer pump according to any of claims 1-8, wherein the tubular flow channel is provided with at least one of the following for assisting the tubular flow channel to be in a substantially vertical position when being submerged: a first element (211) connected to one end of the tubular flow channel (201) and having density smaller than density of water, a second element (212) connected to another end of the tubular flow channel and having density greater than the density of water.

10. Jonkin patenttivaatimuksen 1-9 mukainen vedensiirtopumppu, jossa sähkö-moottorin (103) akseli on kytketty suoraan potkuriroottoriin (102).

10. A water transfer pump according to any of claims 1-9, wherein a shaft of the electrical motor (103) is directly connected to the propeller rotor (102).

11. A water transfer pump according to any of claims 1-10, wherein the water transfer pump further comprises a pontoon (207), a solar cell panel (208) installed on the pontoon, and electrical equipment (209, 210) for driving the electrical motor with electrical energy produced by the solar cell panel.

11. Jonkin patenttivaatimuksen 1-10 mukainen vedensiirtopumppu, jossa vedensiirtopumppu lisäksi käsittää ponttonin (207), aurinkokennopaneelin (208) asennettuna ponttoniin, ja sähkölaitteet (209, 210) sähkömoottorin käyttämiseksi aurinkokennopaneelin tuottamalla sähköenergialla.