DE2514970A1 - ROTODYNAMIC FLUID MACHINE - Google Patents

Description

- ³ AlENTAWALTI]

DR.-ING. BY KREISLER DR.-ING. SCHONWALD DR.-ING. TH. MEYER DR. FUES DIPL.-CHEM. ALEK VON KREISLER

DIPL-CHEM. CAROLA KELLER «BKHtfiSÄlöfeSe» DIPL-ING. SELTING

DR.-ING. K.W. EISHOLD 5 COLOGNE 1, DEICHMANNHAUS

April 4, 1975 Sg-Is

Weir Pumps Limited

149 Newlands Road, Glasgow G44 4EX / Great Britain

Rotodynamic fluid machine

The invention relates to fluid machines for comparatively low delivery heights. Such pumps are for example for land drainage, in sewers and drainage systems and as water turbines used for power generation.

Known pumps for low delivery heads are helical gear pumps, radial axial pumps (mixed-flow pumps) and Axial pumps as volute casing pumps or scoop pumps, and displacement pumps with Archimedean spirals. It is characteristic of the working conditions under which these pumps are used, that the in the Sump, from which the pump delivers, the river entering in terms of its quantity within wide limits can vary, for example due to different

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borrowed amounts of rain and runoff water is. This means that the pumps in economically working pumping systems, which are as low as possible Have power consumption, either need to be able to operate at low flow rates with high efficiency to work, or that several pumps operated in parallel must be installed, which accordingly the resulting additional quantity can be switched on. Another option is to use a storage basin to be provided on the suction side of the pump in order to carry out an intermittent pump operation.

Another feature of the operating conditions such Pumping consists in the incoming river carrying a significant amount of solids in suspension can, some of which can cause abrasion, and that rather large solid chunks get into the sump can, which is especially the case during periods of heavy rainfall, as well as when the specific Weight of such solids is close to that of water.

For such applications with low heads, pumps with Archimedean spirals are often used. Included These are large-volume, low-speed positive displacement pumps that are expensive due to their system. she must be carefully matched to the ascending channels in which they operate, with the greatest possible care small play between the rotor and the channel must be observed in order to obtain a favorable degree of efficiency. This causes considerable construction and manufacturing costs. However, the pumps have the advantage

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that the efficiency over a wide flow range is pretty good as the power absorbed by a positive displacement pump decreases as the flow rate increases decreases. The maintenance of the high efficiency depends on the fact that the work cycle between Rotor and channel remain small in use. In addition, the pump must be used to achieve a favorable degree of efficiency be operated at low speed in order to keep the fluid friction on the large surfaces low. Since the water to be pumped often contains particles that cause abrasion, there is a risk that the game gets bigger over time. Furthermore, it is impossible to have the same size of the working gap with low flow rates and to maintain it with large flow rates, because the water is directed downwards when the pump is at full capacity Exerts force on the rotor, causing it to deform. The working gap must be chosen so that it has the smallest size at maximum rotor deformation. At low flow rates is the weight of the water smaller, so that the deformation of the rotor is also smaller and the gap is wider. This has an adverse effect on the efficiency and energy consumption at low flow rates.

If axial pumps are used for the types of application described, they can only be designed in such a way that that the power absorbed by the pumps at constant speed increases as the flow rate increases decreases. Radial-axial pumps cause the same Problems because they cannot be designed to run less at constant speed Loss of performance if the liquid to be pumped

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quantity becomes smaller. To improve the performance characteristics when working against an almost constant pressure head, For example, in soil drainage or in drainage systems, drives are often used variable speed used. Required for this a complex motor with a commutator, a fluid coupling or another controllable system. Axial pumps and axial-radial pumps require special precautions in the construction of the sump at the pump inlet or storage basin to address the problem dissolve different amounts of liquid and create suitable suction conditions. These factors can cause very high planning costs.

A characteristic of turbines that are operated at low pressure heads is that they are available standing flow rate can vary within wide limits. If such conditions of use exist, one usually uses Kaplan turbines or Francis turbines. These turbines use to adapt to the different flow rates complicated gate control systems for the incoming flow. These gate control systems in Kaplan turbines are supplemented by the fact that the angle of attack of the axially flowed Impeller blades can be adjusted. Such an adjustment mechanism for the angle of attack of the impeller blades is complicated and expensive, but necessary to allow for a significant drop in performance at low flow rates to avoid. Since the use of adjustable blades on the rotor of a Francis turbine is not practical is, the drop in efficiency at low flow rates in Francis turbines is greater than

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with Kaplan turbines.

In the known rotodynamic pumps or centrifugal pumps it is necessary to have a pipe system or a liquid duct between the outlet of the pump, which is normally is either below or only slightly above the liquid level in the inlet sump of the pump, and the level to which the liquid is to be pumped and generally a little more than 2 m above the entrance level is to be provided. This additional pipe system causes in addition to the pump Costs. In addition, the sump at the pump inlet must be carefully and elaborately designed to be suitable Suction conditions for certain rotodynamic pumps known design. For example, the sump must be relatively deep in certain cases so that none Air vortex entrained at the inlet of the pump suction tube will.

The object of the present invention is to provide a rotodynamic Machine to create that regardless of the respective flow rate within wide limits with the same Efficiency can be operated, has a simple construction without critical tolerances, and is able to process liquids that carry solids and cause abrasion without damage.

According to the invention is in a rotodynamic pump for pumping liquid from a low level with a free surface to a higher level, with an entrance located at the level of the lower level

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let and an outlet located at the level of the upper level is provided that between an impeller and the outlet a diffuser is arranged, and that the impeller and the diffuser the entire device for Represents retaining and guiding the liquid between the impeller and the diffuser.

Furthermore, according to the invention, in a rotodynamic Liquid turbine, in which the hydraulic energy by the sinking of liquid from an upper level with a free surface to a lower level Free surface level is obtained, with an inlet at the level of the upper level and an outlet in Height of the lower level provided that the turbine has an impeller and a device for acceleration the liquid between the inlet and the impeller, and that the impeller and the device for Acceleration of liquid is the only means of retaining and guiding liquid between the inlet and the outlet.

Finally, according to the invention, in a rotodynamic fluid machine for operation in liquids, with an inlet and an outlet vertically spaced therefrom, which is mounted on a shaft The impeller is surrounded by an outer jacket and carries blades, which together with the jacket are numerous Form liquid passages along the impeller, the one located in the liquid passages Liquid, forming a vortex, is pressed against the outer jacket and adheres to the radially inner one Interface of the vortex is a free surface

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forms, and that above the impeller an axially extending energy conversion device is arranged, the outer radius of which increases upwards.

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In the following, some exemplary embodiments of the invention are explained in more detail with reference to the figures .

Fig. 1 shows a longitudinal section through a first embodiment of a rotodynamic pump for relative low head.

Fig. 2 shows a longitudinal section through a pump which is similar to that of Fig. 1, but a driven one Has diffuser, and

Fig. 3 shows a further embodiment of a rotodynamic Pump with a fixed diffuser.

The rotodynamic pump shown in Fig. 1 has a hollow thin-walled rotor in the form of an impeller 10 which has a circular cross-section and is mounted substantially vertically. The impeller is open at both the lower and the upper end, The shape of the impeller can vary considerably, however, in the illustrated embodiment, FIG The inner diameter at the upper end 12 is greater than the inner diameter at the lower end 14. The inner diameter increases continuously from the bottom to the top. The rotor impeller 10 therefore has a hollow cone shape.

On the impeller are inside the annular chamber 16 wings 18 attached, which extend through the entire chamber through. The wings 18 are arranged so that they are from the bottom 14 of the rotor 10 or

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extend from the vicinity of the ground to a height 7I, which is preferably just below the upper end 12 of the rotor. That way it gets along of the rotor formed a spiral path. In the embodiment of FIG. 1, the wings are with their inner edges attached to the lower part of the impeller 10 on a hub 20 which is on a vertical drive shaft 22 is attached and rotates with this. The rotating impeller is continued by reinforced an inner jacket 24 attached to the helical vanes 18 above the hub 20, An outer jacket 26 protrudes beyond the lower end of the hub 11 and which is attached to the jacket 26 Wings 18 have inclined end edges so that they radially inward from the outer shell 26 to the hub 20 tower.

The drive shaft 22 rotates in an upper radial thrust bearing 30 which is mounted in a rigid bearing mount 3I. The lower end of the shaft 2 is mounted in a radial bearing 3 ^ mounted in the pump sump J> 6.

The entire pump is on a bracket 32 in one opening 38 of a guide section made of concrete 54 hanging vertically. The opening 38 is circular in plan view and tapers from up down. The converging surface is in the shape of an upside-down bell, what one efficient operation of the pump is important.

The impeller 10 of the pump is mounted so that it

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at its lower end 14 to below the liquid level 40 in the sump J56, from which the liquid is sucked off should be, protrudes. It is generally important that both the outer jacket 26 and the Ends 28 of the wings l8 protrude below the liquid level. Fixed in the swamp Guide means (not shown) attached to the flow to the circular opening at the bottom Guide the end 14 of the impeller and prevent the liquid to be pumped from rotating.

Above the impeller 10 is a device for converting the rotational energy into static energy or a diffuser section 42 is present, the one outer and an inner frustoconical shell 44 and 46, respectively. The jacket form an annular channel 48, the diameter of which increases towards the top, and disposed in the guide vane 75 between the shells 44 and 46.

The diffuser section 42 is freely rotatable on the Pump shaft 22 mounted. For this purpose there are an upper radial bearing 50 and a lower radial thrust bearing 52 provided. The diffuser section 42 is through the The passage of the pumped liquid is rotated,

The light emerging from the diffuser portion 42 fluid flows through a stationary diffuser section ^ k which has no wings and advantageously from the opening 38 is formed forming concrete structure. The stationary section 54 is bell-shaped. The concrete structure with the opening

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is located within the basin into which the liquid is to be pumped.

If the impeller 10 described above from a (not shown) motor at the top of the shaft 22 is driven, liquid is drawn into the helical channel 16 and through the vanes 18 of the impeller set in rotation or in a vortex. This vortex causes the liquid flows upwards in the outer casing 26 of the impeller 10, and that on the inside (at the inside diameter) of the liquid vortex forms a liquid-free surface 60. The surface 6θ of the liquid is substantially circular in cross-section, although the radial depth of the liquid is between two Wings varies and is largest on the front surface of a wing. The liquid will eventually come with it Velocity components in both tangential and vertical directions in the rotatable ones with wings provided diffuser section 42 discharged and flows from there into the stationary wingless diffuser section 5 ^ · When the liquid spirals along the surface of diffuser sections 42 and 54 flows upwards, their velocity energy is converted into static or stationary energy. The curved one Surface of the stationary wingless diffuser section 54 should be designed in such a way that there is a strong vortex-free distribution of the liquid, when this spirals up the diffuser section.

The modified embodiment shown in FIG

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is similar to that of Figure 1 except that the rotatable diffuser section 42 is driven. In FIG. 2, those parts which are the same as those in FIG. 1 are provided with the same reference numerals. As a modification to this, however, the pump shaft 22 is driven by an electric motor 70 via a gear 72. A first output "Jk of the gearbox rotates the pump shaft and a second output 76 drives the diffuser section 42 via a tubular connector 78 which surrounds the pump shaft 22 coaxially.

The gears of the transmission 72 are selected so that the diffuser section 42 at a slower speed rotates as the pump shaft 22.

In a modified embodiment of the diffusers shown in FIGS. 1 and 2, the outer one is The jacket of the diffuser is fixed and the inner jacket, to which the blades are attached, rotates in the outer one A coat. There is a slight play between the outer wing edges and the outer shell. This Embodiment is not shown in the drawing. In another embodiment, are several diffusers arranged one after the other are provided.

In all other points, the exemplary embodiment in FIG. 2 is the same as that in FIG. 1.

In the embodiment shown in FIG. 3, the rotatable diffuser section 42 is omitted and the impeller 10 promotes directly into a stationary one

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Diffuser section 54.

Also in Fig. 3 are those parts that those 1 and 2 are the same, denoted by the reference numerals used there. It should be noted, however, that the lower end of the shaft 22 is not mounted in a bearing here, but that of the support frame 32 an approach protrudes downwards, which is an intermediate storage 134 for the shaft.

The fixed diffuser section 54 does not need to be to be provided with a pilot flight, however, are at the embodiment according to FIG. 3, such guide wings 73 are provided.

Further modified embodiments of the invention Pumps are constructed in essentially the same way as those described above, but with a notable difference. In this modified embodiment, the outer shell 26 is the impeller 10 is not attached to the rotor blades 18 and does not rotate either. The blades of the impeller are on attached to the conical inner shell 24 and the hub 20, which is rotated by the drive shaft 22 are, and run with a fine game between their outer edges and the inner surface of the outer shell 26 around.

In a further modification (not shown), the outer diameter of the impeller is along the length of the impeller constant, which means that the outer shell is cylindrical.

During operation, each of the described

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Pumping, when the liquid level in the pump sump 36 drops, less liquid is drawn into the impeller 10, which is due to the shape of the leading end of the spiral blades. Therefore, the radial depth of the rotating fluid vortex inside the impeller. Because the vortex in which this thinner rotating fluid vortex is only slightly different from the one in to which a radially stronger vortex ring is displaced for larger flow rates, that of the impeller remains generated suction lift almost constant. The power consumption of the rotor falls almost proportionally with the Reduction of the amount of liquid to be pumped. This increases both the volumetric flow rate through the pump and the power consumed, when the liquid level in the sump rises, and they fall as the liquid level in the sump falls off. The pump is self-regulating in this way and works from the maximum throughput to a whole small fraction of this maximum throughput with high efficiency. Your performance with the best possible degree of efficiency cuts compared to conventional centrifugal pumps, axial-radial pumps or axial pumps low because there are no disc friction losses, as is the case with conventional centrifugal pumps and radial-axial pumps (mixed flow pumps) occur. In addition, the leakage losses that occur between Rotor and diffuser occur only very slightly. The friction losses in the fluid passages inside of the impeller and in the rotating diffuser section can in a pump of the type described be kept very low because the relative speed

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fluid properties compared to conventional ones rotodynamic pumps are low for the same delivery head are, and because it is convenient and economical, the cone and the blades of the impeller and diffuser Manufactured from thin, corrosion-resistant sheet metal made from stainless steel or a copper alloy or from reinforced or unreinforced plastic. All of these solutions result in very smooth surfaces, even the stationary ones Diffuser section above the rotor can be made with a very smooth surface.

The pumps described above are very suitable for pumping liquids, which are solids in suspension contain, such as sewer sewage and drainage sewage from storm drains. This suitability is based on the fact that, because no pump housing is required, the pump can be designed to operate with lower maximum Relative speeds run as conventional rotodynamic pumps for similar applications. To this In this way, the risk of damage from solid objects and abrasion is reduced. There is only one very If there is a limited dependence on fine tolerances or close play, the difficulties become the retention of such backlash in the event of abrasion, as is the case in Archimedean screw pumps and conventional ones rotodynamic pumps are avoided. The large distances between the wings in the pump leave it to convey large solids with the pump. The conveyance of such solid material can be supported by a short (not shown) Insertion device for the screw is attached to the lower end of the rotor shaft.

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The vertical suspension of the pump above the pump inlet sump and the lack of a conventional pump housing are the reasons for low installation costs and low space requirements. The rotors can do without Difficulty lifting vertically for inspection or maintenance.

The pumps described above can also be operated as turbines for low pressure heads if the Liquid flow is reversed. The volumetric flow is regulated by the fact that an annular Gate valve at the top of the pump is raised and lowered to the radial depth of the spiral into the opening 58 flowing flow and thus to influence the output power of the turbine. The turbine has a high maximum efficiency and maintains a high efficiency over a long period Flow range upright at constant speed. This gives you an excellent hydraulic system Prime mover for power generation.

With the embodiments described above and Modifications of the invention do not require complex ones Multiple doors and wings with variable angles of attack, such as those for Kaplan and Franc! S liquid turbines used to use. The machine according to the invention can, however, in terms of its performance compete with said machines over a wide range of flow rates.

If a pump according to FIGS. 1 and 2 is used for liquids which contain solids in suspension,

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is achieved through the use of a rotatable diffuser area 42, which has rotating vanes 75, ensures that all solid components from the Communicated centrifugal forces in both the impeller 10 and the rotatable diffuser area 42 will. In this way, any solids entering the impeller 10 through the bottom opening can forced to be driven to the upper end of the rotatable Diffusorbereich.es 42, regardless of the volumetric flow rate of the liquid. The kinetic The energy of the solid parts is sufficient together with the entrainment effect acting on the solid parts of the liquid flow in general out to the solid parts over the remaining flat stationary bell-shaped diffuser area 54, Q.h. to the level of the pump outlet. In cases where solids are exceptionally difficult to pump are present, the stationary diffuser area 54 at the top of the pump can be omitted. Included there is some loss of effectiveness of the diffuser and therefore a reduction the overall efficiency of the pump. Large distances between the blades in the rotatable diffuser mean that large-format solids can be promoted with it.

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Claims (1)

25H970 - ι S - Expectations 1.) Rotodynamic pump for pumping liquids from a low level with a free surface to a higher level, with one on top the inlet located at the lower level and an outlet located at the level of the upper level, thereby characterized in that a diffuser (42) is arranged between an impeller (10) and the outlet, and that the impeller (10) and the diffuser (42) includes all of the means for retaining and guiding the liquid therebetween represents the impeller (10) and the diffuser (42). 2. Pump according to claim 1, characterized in that the pump with substantially constant speed driving drive device is provided. j5. Pump according to claim 1 or 2, characterized in that that the axes of the impeller (10) and the diffuser (42) are essentially vertical. 4. Rotodynamic liquid turbine, in which the hydraulic energy from the sinking of liquid from an upper level with a free surface is recovered to a lower level with a free surface, with an inlet at the level of the upper one Levels and an outlet at the level of the lower level, characterized in that - 19 509843/0657 25U970 the turbine has an impeller (10) and a device (42) for accelerating the liquid between the inlet and the impeller, and that the impeller and the device (42) for acceleration of liquid is the only means of retaining and guiding liquid between the inlet and the outlet. 5. Turbine according to claim 4, characterized in that the axes of the impeller (10) and the liquid accelerating device (42) are substantially vertical. 6. Rotodynamic fluid machine for operation in liquids, with an inlet and an outlet vertically spaced therefrom, characterized in that that the impeller (10) mounted on a shaft (22) is surrounded by an outer casing (26) and carries vanes (18) which together form with the jacket numerous fluid passages along the impeller, the fluid in the fluid passages forming a vortex forming, is pressed against the outer jacket and is located on the radially inner boundary surface of the Strudels forms a free surface (60), and that above the impeller one extends in the axial direction extending energy conversion device (42) is arranged, the outer radius of which increases upwards. 7. Fluid machine according to claim 6, characterized in that g e - - 20 509843/0657 25U970 indicates that the shaft (22) is oriented substantially vertically. 8. Fluid machine according to claim 6 or 7, characterized in that the radius of the outer shell (26) increases towards the top. 9- fluid machine according to claim 6 or 7 * thereby characterized in that the outer jacket (26) is cylindrical. 10. Fluid machine according to one of claims 6 to 9, characterized in that the wings (18) are mounted in a spiral. 11. Fluid machine according to one of claims 6 to 10, characterized in that the blades (18) are attached to a hub (20) carried by the lower end of the shaft (22). 12. Fluid machine according to one of claims 6 to 11, characterized in that the outer shell (26) is mounted to the shaft (22) and the blades (18) are attached to it. 15. Fluid machine according to one of claims 6 to 11, characterized in that the outer jacket (26) is attached non-rotatably, and that there is a game between the wings (18) and the jacket (26). 509843/0657 - 21 - 25U970 14. Fluid machine according to one of claims 11 to Γ3, characterized in that there is provided an inner jacket (24) extending from the upper The end of the hub (20) goes out and supports the wings (18) above the hub. 15. Fluid machine according to one of claims 11 to 14, characterized in that the outer jacket (26) and the wings (18) to below the lower end of the hub (20) protrude, and that the lower ends of the wings (l8) as far as they are from the hub (20) protrude radially outwards, are beveled downwards. 16. Fluid machine according to one of claims 6 to 15 * characterized in that the energy conversion device (42) is rotatably mounted about the axis of the impeller (10) and has blades (75). 17. Fluid machine according to one of claims 6 to 16, characterized in that the energy conversion device (42) is freely rotatable about the shaft (22) of the impeller. 18. Fluid machine according to one of claims 6 to l6, characterized in that the energy conversion device (42) is driven at a speed that is slower than the speed of rotation of the impeller (10). - 22 - 509843/0657 25U970 19 · fluid machine according to one of claims 16 to 18, characterized in that the guide vanes (75) of the energy conversion device (42) are formed towards the inner jacket (46) and attached to it. 20. Fluid machine according to claim 19, characterized in that an outer jacket (44), which forms the energy conversion device, is fixedly arranged, and that between the outer edges the guide wing (75) and the outer shell (44) there is a running game. 21. Fluid machine according to one of claims 6 to 20, characterized in that the energy conversion device has an annular, bell-shaped widened fixed passage (54) having. 22. Fluid machine according to claim 18, characterized in that the energy conversion device (42) and the impeller (10) are driven by the same motor (70) via a gear (72), and that the gear ratios are chosen so that the energy conversion device (42) with less Speed rotates as the impeller (10). 23. Fluid machine according to one of claims 16 to 22, characterized in that a plurality of rotatable energy conversion devices are arranged in series one behind the other. - 23 - 5098Λ3 / 0657 25U970 24. Fluid machine according to one of claims 6 to 14, characterized in that the impeller '10) and the energy conversion device (42) consist of sheet metal. 25. Fluid machine according to one of claims 6 to 14, characterized in that the impeller QO) and the energy conversion device (42) are made of plastic. 26. Fluid machine according to one of claims 6 to 25, characterized in that in the vicinity of the lower end of the impeller (10), but at a distance therefrom, stationary guide plates for Preventing pre-rotation of the in the acting as a pump operated machine are provided inflowing liquid. 27. Fluid machine according to one of claims 6 to l8, characterized in that when the turbine is in operation, a shut-off device at the inlet to regulate the amount of water passing through the machine Fluid flow is provided. 5098 ^ 3/0657 %H Blank page