EP0069604A1 - Hydraulic pumps or motors with helicoidal gears (screw turbines) - Google Patents

Abstract

A turbine of the screw type, in which the stator (1) and the rotor (2) have the geometry of screws generated by deformed epicycloid or hypocycloid curves. The screw of the stator (1) comprises, in the zones of a change of radius of curvature of the same stage, guide elements (6) which project slightly relative to the surface of the stator (1) and with which the rotor screw (2) comes into contact during its movement. The stator (1) comprises a succession of stages with guide elements arranged side by side over its entire length, and the geometries of the rotor (2) and stator (1) are determined in such a way that a play remains at the lines of contact between the rotor and stator, this play being substantially equal to the protuberance of the guide elements (6). <IMAGE>

Description

In pumps or helical gear motors, the rotary piston (s) have the geometry of screws generated by a deformed epicycloid or hypocycloid curve, movable in a stator which itself has the geometry of a screw generated by the curve of the same family as the rotor, but of parameter (n + 1) when the rotor is of parameter n, and of pitch h (n + 1) when the pitch of the rotor is of pitch hn. so that both screw surfaces are always tangent along (n + 1) continuous lines along the screws.

Such devices are described in particular in French patents 695,539, 787,711, 2,372,333 and are generally called pumps of the MOINEAU type.

However, these devices have not received in practice important applications despite their theoretical interest, in particular because of the sealing and friction problems which they pose and which are very different according to the envisaged applications, in particular according to that they are high or low pressures, ranges of more or less large flow rates, axial speeds of low or high fluids.

In particular, the known applications all relate to uses or applications as pumps or high pressure motors, the use of these devices for large flows and low pressures having hardly been implemented.

The present invention relates to the application of these devices to the use of low-drop hydraulic power. This is in particular the transformation of hydraulic energy from tides or rivers. By the means of the invention, such low-drop hydraulic energy can be transformed into mechanical energy, heat energy or energy. hydraulic with different characteristics as well as mechanical energy can be transformed into low-drop hydraulic energy,

In the description which follows, the device is designated by the expression screw turbine, so as not to distinguish a priori the operation in motor and the operation in pump.

In the case of low drop energy, these are generally large liquid flows with a low drop height. In such applications, perfect sealing between the screws is not necessary and leaks can be tolerated up to some for the total flow due to the low kinetic energy of the fluid, On the other hand, it is very important that the turbine is able to operate with an impure liquid, such as cloudy water, containing solid bodies in suspension, excluding excessively large bodies which can be removed using a simple grid. Therefore, it is necessary that the screws do not touch and preferably, that the screws are established so as to admit solid bodies significantly larger than the clearance between the screws.

The turbine according to the invention is for this purpose characterized in that the stator screw comprises, in the zones of change of radius of curvature of the same stage of the elements guides such as idle rollers slightly projecting from the surface of the stator and on which the rotor screw comes into contact, the stator comprising a succession of stages with guide elements placed side by side over its entire length, and the geometries of the rotor and the stator being determined so that there remains a clearance in the contact cloths between rotor and stator, this clearance being substantially equal to the prominence of the guide elements.

By stage is meant a section perpendicular to the axis of the screw and of sufficient thickness for the housing of the guide element (roller or other). Preferably, the rotor and the stator are produced by helical stacking of identical sections between them, with cylindrical walls parallel to the axis of the screw and the stages of guide elements coincide with the sections of the screw (stator and rotor).

As guide element, in accordance with the invention, rollers housed in the wall of the stator and with an axis parallel to the axis of the screw, or balls or rollers, or projecting pads or other arrangements known in hydraulic technology under the term of hydraulic wedges.

Another arrangement of the invention consists in that the rotor screw is mounted rotating freely around an axis (crank) connected at its ends by crank arms to the turbine shaft, the shape of which thus resembles that of a crankshaft.

This ensures the orbital movement of the rotor screw around the axis of the stator and the rotational movement of the rotor screw around its axis without the rotor and the stator touching each other, the rotor being guided with play with respect to the stator. by the system of stages of rollers carried by the latter and entering in rotation on its axis by the effect of the orbital movement conjugated with the guide with rollers.

This assumes, for correct operation, that the stator axis and the rotor axis remain strictly parallel, which is obtained by rigidly fixing the crank to the two arms of the crankshaft and by dimensioning it so that the torsional forces to which it is subjected creates parallelism faults less than the expected clearance (total deviations of the ends of the crank from the exact parallelism).

The low-drop hydraulic energy can thus be transformed by simple and efficient means into mechanical energy (and vice versa), with very rough construction means.

This mechanical energy can be used directly but it can also, according to a provision of the invention be transformed into hydraulic energy by the creation of a secondary current of higher pressure and lower flow rate by means of a positive displacement pump which can also be a screw pump.

The invention provides for this application the use of a turbine with two screws, in which the rotor of the first screw serves as a hollow envelope for the second screw, the water inlet being common to the two screws while the outputs are separate.

With such a device, the ratio of the pressure at the outlet of the second turbine to the pressure at the inlet of the first is the inverse of the ratio of the unit volumes of the two turbines (closed volume between stator and rotor over one revolution of screw). The water thus pumped can be stored in a tank placed at a level above the reach in the same relationship to the initial height of fall. This energy can also be used to drive hydraulic motors providing an output speed greater than the speed of the first turbine, According to the invention, the pump driven by the first turbine can also be a positive displacement pump sucking water from a reservoir to discharge it into the same reservoir via a valve and a load breaker, the opening of this valve being controlled by the level of the upstream reach and the hot water intake made on the pump discharge circuit upstream of the valve.

• La figure 1 est une vue perspective d'une turbine selon l'invention ;
• La figure 2 est l'épure d'un étage de la turbine de la figure 1 ;
• La figure 3 illustre schématiquemnt le guidage obtenu ;
• La figure 4 illustre un détail constructif ;
• La figure 5 illustre une variante de construction ;
• La figure 6 est l'épure d'un étage d'un transformateur de pression hydraulique selon l'invention ;
• La figure 7 est une coupe axiale du dispositif de la figure 6, selon A-A ;
• La figure 8 illustre schématiquement l'utilisation de l'appareil en générateur de chaleur.

These provisions, as well as others, will be described more fully below with reference to the attached drawing, in which:

• Figure 1 is a perspective view of a turbine according to the invention;
• Figure 2 is the sketch of a stage of the turbine of Figure 1;
• Figure 3 illustrates schematically the guidance obtained;
• Figure 4 illustrates a constructive detail;
• Figure 5 illustrates a construction variant;
• Figure 6 is the sketch of a stage of a hydraulic pressure transformer according to the invention;
• Figure 7 is an axial section of the device of Figure 6, along AA;
• Figure 8 schematically illustrates the use of the device as a heat generator.

The turbine of FIGS. 1 and 2 consists of a hollow casing forming a stator 1 in which a rotor screw 2 moves. As known, the screw 2 is formed from a stack of circular discs 3, the stator 1 being formed from a disc stack 4 each comprising an oblong opening 5. The relative geometric shapes of the discs 3 and the openings 5 are the shapes known and described in the prior art cited above,

As can be seen in FIG. 1, the turbine according to the invention, intended for low falls, is of large diameter relative to its axial length which is generally less than the diameter. For high flows at low height, for example 3m ³ / sec, at a fall of 2m, the diameter could be of the order of 4m, for a length of 2m,

In the example shown, each assembly formed by an internal disk 3 and an external disk 4 constitutes a stage and the internal face of the opening 5 of a stage of the stator 1 comprises, in each zone for changing the radius of curvature of a guide element 6, roller, ball or roller, or hydraulic wedge, slightly projecting from the internal surface of the stator, while the radius of the disc 3 is slightly less than the radius of curvature of the curved parts of the opening 5 .

The rotor screw comes to bear successively on the rollers of each stage during a fraction of its orbital movement which depends only on the unit angle which separates the position of a disc 3 from the following around the axis of the turbine. The guidance of the rotor screw is therefore analogous to that of a wheel 7 moving on a succession of rollers 8 as shown in FIG. 3.

We thus obtain as perfect guidance as we want of the rotor screw 2 in the stator 1 without these parts touching each other, so that there is always a clearance which on the one hand virtually eliminates losses by mechanical friction. , on the other hand allows the use of liquids charged with solid impurities,

To perfect this characteristic, the invention provides on the one hand to give the rollers an elasticity of suspension (for example elastically repelled rollers) or active or rolling surface (elastomer surface) and on the other hand to produce in flexible and elastic material the surface of at least one of the two screws, for example to produce the discs 3 with a thickness or edge of rubber or other elastomer, preferably cellular.

Furthermore, the shaft 8 of the turbine has the form of a crankshaft whose crank 9 constitutes the shaft around which the rotor 2 freely rotates, this crank being connected to the shaft 8 by the arms 10. For example the disks 3 will be mounted on a hollow sleeve 11 swiveling around the shaft 9 secured to the arms 10 themselves secured to the shaft 8.

This gives great rigor in orbital displacement of the shaft 9 without contact between the screw 2 and the stator 1 other than the contacts of the rollers or the like 6. The clearance between the rotor screw 2 and the stator 1 at the contact lines between screws may be of the order of several millimeters for an average diameter of rotor screws of the order of 1 meter. To ensure such operation properly, the crankshaft 8, 9, 10 must be very rigid so that the torsional forces to which it is subjected do not reduce the advantages resulting from this play. More precisely, the crank 9 and the arms 10 will be calculated on which it is rigidly fixed so that the distance between its ends with respect to the exact parallelism cannot exceed the chosen value of the clearance under the conditions of service provided.

This mode of constitution of the screw turbine, suitable for low falls, allows the production of very bulky machines with very rough means for inexpensive energy recovery despite very low heights of fall, of the order of 1 meter for example. The dimensions to which this adaptation leads can be very large and pose an implementation problem with regard to the lower bearing which must support the weight of the rotor 2 plus the pressing force, According to the invention, this difficulty is overcome by providing a rotor provided with cavities filled with air and such that the density of the rotor is less than that liquid of the fall, Preferably, the cavities will be of adjustable volume, for example in the form of tight ballasts with controllable filling, making it possible to adjust the density; but we can also use a rotor inside which are arranged volumes of cellular material. Such volumes or ballasts are shown in dotted lines at 12 in FIG. 2.

By way of example, a turbine as shown in FIG. 1, having an external diameter of 108 m, a disc diameter 3 of 40 m, a stator height 1 of 40 m can accept a flow rate of 5000 m ³ / sec. under a drop height of 2 mt, with a clearance between rotor and stator allowing the passage of solid impurities of the order of 10 cm. Such a machine is capable of providing 100 megawatts of raw power. It can be carried out with very crude means such as the means of shipbuilding.

Since the guidance can be established with large clearances between rotor and stator, the profile to be given to each stage can be that of a simple stair step as shown in Figure 4 (section along a plane passing through the axis of the rotor) . It is also possible to cut the stages along the dotted lines 13 and 14 (FIG. 5), that is to say according to the surface generated by the segment joining two homologous points 15 and 16 of two discs of two successive stages. Such an arrangement is more expensive to make but allows greater play for the same leak rate.

With such a machine, for example because of the high flow rates and the low height of fall, the speed of rotation of the shaft 8 can be very low, of the order of a few revolutions per minute, and too irregular, at due to variations in flow, to be used directly as mechanical energy. But it can then be used to drive a similar machine for the production of hydraulic energy which can be used as such or serve for the production of heat, for example for the production of a flow of hot water.

Figure 6 illustrates such a hydraulic power transformer. According to this figure, inside the turbine constituted by the stator 17 and rotor 18 screw assembly, produced as described above with a clearance between stator and rotor by means of rollers or the like 6, is a pump with screw constituted by the helical screw 19 rotating relative to the helical space 20.

The prior art already knows the use of several turbines with internal screws to one another and of the same distance, in particular French patent 78.7711, but in these applications these are additions of fluid flow rates to limit the size of the pump and the volumetric spaces of the screw devices are used in parallel, the intermediate screw having a small thickness.

Unlike this application, the present invention provides for the use of one of the motor spaces and of the other pump space, the mechanical energy resulting from the motor operation being used to drive the pump, and the spaces volumetric having a ratio corresponding to the pressure ratio to be obtained.

In this perspective, according to the invention, the inputs 21 and 22 are common but the outputs 23 and 24 are separated and the liquid entering the external screw turbine 17-18 serves to supply the mechanical compression energy of the pump formed by the assembly 19-20 so that at the outlet of the pump 19-20, a liquid is obtained whose pressure is, relative to the pressure, determined by the height of fall which is available in the turbine 17-18 , in the same proportion as the volumetric ratios of the closed enclosures of screws 17-18 relative to those of screws 19-20,

In order to be able to increase this transformation ratio, the invention provides for using for the screw 17-18 a geometry of transformed or deformed hypocycloids with at least three vertices while the pump 19-20 has a geometry of transforms of hypocycloids with 1 and 2 vertices,

On the other hand, for the same purpose, the invention provides for giving the internal screw 19-20 a smaller center distance than that of the screw 17-18, which results in shorter crank arms 10b. that arms 10a,

The fact that the two screw turbines use the means of the invention, that is to say the guide by rollers and the rigid crankshaft 41, makes it possible to have no other mechanical connection between the stator and rotor screws of each turbine.

Indeed, the forces received or provided by the pressure of the water on the internal screw 19-20 are always normal to the crankshaft crank whatever the position of the screw. There is therefore no energy to be supplied or received at the level of the guide and all the energy transmission takes place by the torsional strength of the crankshaft without any other mechanical connection.

The practical realization of the device therefore remains very simple with the main organ a double crankshaft, the crank of the external turbine 17-18 constituting the shaft of the internal pump 19-20 and the crank arms 10a, 10b (spacing of the screws) can be of different lengths.

In the case where the arms 10a, 10b are the same length, the movement of the screw 19 is reduced to a rotational movement around the general axis of the device. If they are from different lengths, this movement is more complex, but due to the absence of mechanical connection, its realization poses no problem.

For the sealed separation of the fluid outlets, the solution shown in Figures 6 and 7 can be adopted; the external shape (stator 17) can be made of concrete with a flat bottom 42, the surface of which can be coated with a smooth material such as a sheet of stainless steel. The rotor screw 17 is provided with a rubber skirt 43 which slides over this surface and seals between the pressurized water of the cavity 23 and the pressureless water of the cavity 24. This bottom has separate orifices outlet: on the one hand, the three orifices 38 which discharge downstream, via the underground passages 24, the water having passed through the turbine 17-19; on the other hand, the orifice 40, in the center, connected by the underground 23 at the place of use of the water thus pressurized by the screws 19-20.

FIG. 8 illustrates the use of such a hydraulic energy transformer as a heat generator. In this use, the mechanical energy resulting from the operation of a low-drop turbine 25 such as that of FIG. 1 is used in the drive 26 of a positive displacement pump 27 working in a closed circuit in a tank 28, insulated at 39 The pump 27 draws the liquid at 29 to return it to the reservoir at 30 by means of a valve-nozzle 31, that is to say a valve transforming the pressure into speed, and dissipating this speed into turbulence by any circulation in the reservoir 28; the liquid is then taken up in 29 to undergo the same cycle again, Under these conditions the water heats up and it becomes possible to take from the high pressure stage at 32, a flow of hot water corresponding to the production of machine calories: at the low pressure stage, at 33, the same quantity of cold water will be reinjected into the circuit.

However, the water flows from the upstream reach 34 to the downstream reach 35 can vary within wide limits, for example if it is a river. To make the best possible use of the energy thus available, the invention provides a regulation system consisting in regulating the closing of the valve 31 as a function of the level of the upstream reach 34, by means of the float 36 connected to the valve 31 by the linkage 37. When the float 36 rises, the valve 31 opens. The pressure in the high pressure stage of the pump system 27 reservoir 30 decreases, which allows the speed of the turbine 25 to be increased, which thereby , absorbs more water. This is in contrast to the upstream water rise movement which reduced the pressure on the high pressure stage. Conversely, a lowering of the upstream level 34 causes the valve 31 to close and the outlet pressure of the pump 27 to rise, which requires the turbine 25 more energy than it can supply. The turbine 25 will slow down its movement, thus absorbing less flow, which is opposed to lowering the upstream level 34. This regulation therefore makes it possible to operate the system in a very wide range of related flows while maintaining the level upstream at the maximum level authorized by the site, the turbine 25 and the entire system operating as an upstream level regulator. The flow of calories available in 32 will vary with the flow of the river. In winter, it may be sufficient for a central heating installation or a substantial supplement, in summer it may be sufficient for the consumption of hot water for toilet or household use.

A hydraulic power transformer with a large operating range is thus obtained, consisting of a turbine according to the invention operating as a motor, and driving a positive displacement pump 27 whose resistive torque is regulated by a valve 31 as a function of the upstream level, the recovery thus being optimized by maintaining the potential of the fall at its optimum level.

Therefore, as a variant, the pump 27 can be the compressor. gas from a heat pump type system, that is to say that the energy transformer and the regulation thus described also apply in the case of the drive of a heat pump.

Claims (16)

1. Screw turbine of the type in which the stator (1) and the rotor (2) have the geometry of screws generated by deformed epicycloid or hypocycloid curves, characterized in that the screw of stator 1 comprises, in the change zones of radius of curvature of the same stage of the guide elements 6 slightly projecting from the surface of the stator (1) and with which the rotor screw (2) comes into contact during its movement, the stator (1) comprising a succession of stages with guide elements placed side by side over its entire length, and the geometries of the rotor (2) and of the stator (1) being determined so that there is a clearance at the contact lines between rotor and stator, this play being substantially equal to the prominence of the guide elements (6). 2. Turbine according to claim 1, characterized in that each stage consists of a section perpendicular to the axes of the screws and of sufficient thickness for the housing of the guide element. 3. Turbine according to any one of the preceding claims, characterized in that the rotor (2) and the stator (1) are produced by helical stacking of sections (3, 4) identical to each other, with cylindrical walls parallel to the axes of the rotor and stator screw and the stages of guide elements coincide with the edges of the screw, 4. Turbine according to any one of the preceding claims, characterized in that the guide elements are of the rollers, balls, rollers, skids, projections and other hydraulic wedges. 5. Turbine according to any one of the preceding claims, characterized in that the guide elements 6 are provided with elasticity of suspension or active surface. 6. Turbine according to any one of the preceding claims, characterized in that the surface of at least one of the two stator (1) and rotor (2) screws is produced with a thickness of flexible and elastic material, preferably cellular . 7. Turbine according to any one of the preceding claims, characterized in that the rotor screw (2) is mounted rotating freely around a crank shaft (9), connected at its ends by arms (10) integral with the stator shaft (8). 8. Turbine according to claim 7, characterized in that the crank shaft (9) around which the rotor screw (2) rotates is rigidly linked to the arms (10) and dimensioned so that the torsional effects to which it is subjected create parallelism defects less than the expected clearance, 9. Turbine according to any one of the preceding claims, characterized in that the clearance provided between rotor and stator along the contact lines is several millimeters for an average diameter of rotor screw (2) of the order of 1 m . 10. Turbine according to any one of the preceding claims, characterized in that the profile of each stage is that of a stair step. 11. Turbine according to any one of claims 1 to 10, characterized in that the profile of each stage is the surface generated by the segment joining two homologous points of two successive stages. 12. Turbine according to any one of the preceding claims, characterized in that the rotor screw of the turbine serves as a hollow envelope for a second screw of the same type, the water inlet being common to the two screw turbines thus obtained while the outputs are separate and the energy mechanical resulting from the engine operation of the external turbine being used to operate the internal turbine as a pump. 13. Turbine according to claim 12, characterized in that the external turbine forming a motor has a geometry derived from hypocycloids with at least 3 vertices while the internal turbine forming a pump has a geometry derived from hypocycloids with 1 and 2 vertices , 14. Double turbine according to any one of claims 12 and 13, characterized in that the rotors of the two turbines are both mounted according to claim 7, the crank of the external turbine constituting the crankshaft of the internal turbine. 15. Double turbine according to claim 14, in which the crank arms of the internal turbine are of different lengths from those of the external turbine, 16. Hydraulic power transformer constituted by a hydraulic motor according to any one of the preceding claims, driving a positive displacement pump whose resistive torque is regulated by a valve as a function of the upstream level.

Images