EP3249155A1 - Device for actuating an air motor - Google Patents

Abstract

The invention relates to a device provided with a vacuum source for actuating a motor (100), which motor consists of a cylinder (110) inside which a piston (120) separating the cylinder moves in two chambers. (111, 112) whose volume varies as a function of the displacement of the piston in the cylinder, the piston being provided with a rod (130) projecting from the cylinder at the end of one of the two chambers, each chamber being provided with at least one intake valve and at least one exhaust valve, a distributor being provided for alternately connecting the chambers (111, 112) to a vacuum source via their exhaust valves and at atmospheric pressure via their intake valves. According to the invention, the vacuum source comprises at least one vacuum outlet placed in a Venturi effect device (200).

Description

The invention relates to a device for generating a vacuum for actuating an air motor according to the preamble of claim 1.

The invention aims to operate an engine according to the preamble without releasing pollutants such as gaseous waste (greenhouse gas) or radioactive waste (nuclear plant waste for example).

The search for new renewable energies has accelerated in recent decades to respond to energy and environmental crises and to reduce air pollution. On the other hand, the climate change we are observing is largely due to the release of greenhouse gases. According to specialists, dams, wind turbines and solar energy also have negative effects on the environment. It is therefore important to constantly improve them, because despite everything, the energy they produce is clean and without rejections.

Air motors have long been known to operate not under the influence of overpressure, such as steam engines, but under the effect of a vacuum. Generally, such an air motor consists of a cylinder closed at both ends and inside which moves a piston separating the cylinder into two chambers whose volume varies as a function of the displacement of the piston in the cylinder. The piston is provided with a rod protruding from the cylinder at the end of one of the two chambers. Each chamber is provided with at least one intake valve and at least one exhaust valve. Each chamber can be connected through its exhaust valve to a vacuum generator and its intake valve to ambient air. When the exhaust valve of one chamber is opened, the inlet valve of this chamber is closed, while in the other chamber the intake valve is open and the exhaust valve is closed. The exhaust valves are connected in turn to the vacuum generator. It is common for the intake and exhaust valves of the same chamber to be confused. A distributor may be provided for alternately connecting the chambers to a vacuum generator via their exhaust valves and at atmospheric pressure via their intake valves.

The object of the invention is to operate an air motor of the type mentioned above by using a renewable and clean energy source that does not harm the environment. A second objective is to improve the performance of dams. Another objective is to improve the quality of river water or that coming out of dams. A fourth objective of the invention is to contribute to the depollution of the air.

These objectives are achieved because the vacuum source used to operate the air motor comprises at least one vacuum outlet placed in a Venturi effect device to be placed in a flow of gravity water. The vacuum port of the Venturi device is connected to the motor valve. The air sucked in to operate the piston is introduced into the stream of water that helps to oxygenate it, which has a beneficial effect on aquatic fauna and flora. By gravity water, one understands a water which is mobilizable by gravity. This exploits the potential energy of water flow which, transformed into kinetic energy, makes it possible to generate a vacuum for operating an air motor. It can be water from a dam or water from a watercourse.

In a first embodiment of the invention, the Venturi effect device comprises a Venturi tube placed in a pipe made in a hydraulic dam. In a first variant embodiment, the vacuum tap of the Venturi tube is placed in a restriction made for this purpose in the pipe. The pipe may have no other function, or the restriction is placed in an existing pipe, away from a turbine so as to have no effect on the operation thereof.

In a second variant, the vacuum outlet of the Venturi tube is placed in an already existing restriction in the pipe, at a turbine. In a first example, the vacuum tap is placed in a restriction located downstream of a turbine of the hydraulic dam, at the beginning of the suction pipe. This solution is particularly well suited to Francis turbines.

In a second example, the evacuation of the Venturi tube is placed at the end of the water supply pipe, or close to it, preferably in the low pressure zone in the vicinity of the blades of the turbine. . In particular, the vacuum outlet may be placed upstream of the blades of a turbine of the hydraulic dam and / or directly downstream of these. This solution is intended for example for Kaplan turbines or bulb type turbines.

In a third example, the Venturi tube is placed in a dam operating with Pelton turbines which use a needle to regulate the flow out of the water supply line of the turbine. The needle is attached to the end of a control rod and is movable in a nozzle. According to the invention, the control rod and the needle are hollow and in communication with each other, the end of the needle opposite the control rod being open, and the control rod serving as a vacuum to the Venturi tube.

For a better distribution of the air inlet in the pipe, it is preferable that the vacuum outlet comprises several openings distributed around the periphery of the pipe and that these openings are placed in the same radial plane.

In a second embodiment, the Venturi effect device is placed in a stream of water in the open air, preferably in a watercourse or in a hydraulic dam weir. Torrents are particularly well suited to this type of application as well as the weirs of dams. In such cases, the device Venturi effect may be constituted by at least one hydrofoil type structure, one or more openings being made in each hydrofoil, in an area in which a depression is formed when the hydrofoil is immersed in a current of water, each hydrofoil type structure being connected to a pipe acting as a vacuum for the engine. It is preferable to provide check valves at the junction between each hydrofoil type structure and the pipe and / or in each opening. Depending on the available depth, a plurality of hydrofoil structures may be placed one above the other in the watercourse at a distance from each other, preferably without inclination forming a battery.

In order to improve the quality of the ambient air, it is possible to place an air filter upstream of the Venturi tube vacuum outlet. Thus, the sucked air is filtered before being injected into the stream of water. The filter can be placed for example in the engine air supply line.

Figure 1 :

Schéma de principe d'un moteur à air ;

Figure 2 :

vue d'un tube de Venturi de type multiétage placé dans un courant d'eau, par exemple une rivière ou un déversoir en sortie de barrage ;

Figure 3 :

coupe à travers un barrage avec une conduite munie d'une restriction et de plusieurs prises de vide pour actionner le moteur à air, à la façon d'un Venturi multiétage;

Figure 4 :

vue d'une conduite d'un barrage munie d'une prise de vide au niveau d'une turbine Francis ;

Figure 5 :

vue d'une conduite d'un barrage munie d'une prise de vide au niveau d'une turbine bulbe ;

Figure 6 :

vue d'une conduite d'un barrage munie d'une prise de vide au niveau d'un injecteur d'une turbine Pelton ;

Figure 7 :

représentation schématique d'un pointeau pour un injecteur selon la figure 6 ;

Figure 8 :

coupe éclatée du pointeau de la figure 7 ;

Figure 9 :

coupe agrandie du pointeau de la figure 7 muni de valves unidirectionnelles placé dans la buse de l'injecteur ;

Figure 10 :

coupe agrandie au niveau d'une valve unidirectionnelle ;

Figure 11 :

vue de dos de la partie avant du pointeau de la figure 7 ;

Figure 12 :

représentation schématique d'un moteur à air actionnant une roue et raccordé à une prise de vide dans une restriction située dans une canalisation d'un barrage ;

Figure 13 :

représentation schématique en coupe de côté d'une batterie de structures de type hydrofoil placées dans un courant d'eau à l'air libre ;

Figure 14 :

représentation schématique en perspective de la batterie de structures de type hydrofoil de la figure 13 ;

Figure 15 :

représentation schématique de face de la batterie de structures de type hydrofoil de la figure 13.

The invention is described in more detail with the aid of the following figures which show nonlimiting examples of embodiment of the invention:

Figure 1 :

Schematic diagram of an air motor;

Figure 2:

view of a multi-stage Venturi tube placed in a stream of water, for example a river or a spillway at the outlet of the dam;

Figure 3:

cut through a dam with a pipe with a restriction and several vacuum plugs to operate the air motor, like a multi-stage Venturi;

Figure 4:

view of a line of a dam equipped with a vacuum intake at a Francis turbine;

Figure 5:

view of a pipe of a dam equipped with a vacuum outlet at a bulb turbine;

Figure 6:

view of a pipe of a dam equipped with a vacuum outlet at the level of an injector of a Pelton turbine;

Figure 7:

schematic representation of a needle for an injector according to the figure 6 ;

Figure 8:

exploded cut of the needle of the figure 7 ;

Figure 9:

enlarged cut of the needle of the figure 7 equipped with unidirectional valves placed in the nozzle of the injector;

Figure 10:

enlarged cut at a unidirectional valve;

Figure 11:

view from the back of the front part of the needle of the figure 7 ;

Figure 12:

schematic representation of an air motor operating a wheel and connected to a vacuum intake in a restriction located in a pipe of a dam;

Figure 13:

schematic representation in side section of a battery of hydrofoil type structures placed in a stream of water in the open air;

Figure 14:

schematic representation in perspective of the hydrofoil-type structure battery of the figure 13 ;

Figure 15:

schematic front view of the hydrofoil type structure battery of the figure 13 .

For a better understanding of the figures, the water is generally represented by an arrow in solid line, while the air is represented by an arrow in broken lines.

The object of the invention is in particular to increase the efficiency of a hydraulic power plant by operating, parallel to conventional turbines, an air motor using a vacuum source and ambient air as a source of energy.

The figure 1 shows the block diagram of operation of such an air motor (100). This engine works much like a compressed air engine, but instead of using a source of compressed air, it uses a vacuum source. The main element of the engine is a double-acting cylinder (110) closed at both end faces and in which a piston (120) moves, forming two chambers (111, 112) whose volume varies as a function of the displacement of the piston. piston inside the cylinder. A rod (130) is attached to the piston and protrudes through one of the faces of the cylinder. The rod is connected to a mechanism (140) that converts the translation movement of the rod (130) into a rotational movement that can be used to drive an unrepresented alternator. Each chamber is provided with at least one intake valve and at least one exhaust valve, the intake valves and the exhaust valves of the same chamber being confusable (113, 114). A dispensing spool, not shown, alternates the vacuum intake and the ambient air inlet in the two chambers depending on the position of the piston in the cylinder. Thus when a chamber (112) is in contact with the vacuum source, the other chamber (111) is in contact with the ambient air. When the piston is close to its end of travel, the connections are reversed and the chamber (112) that previously was in contact with the vacuum source is now in contact with the ambient air, while the other chamber (111 ) is connected to the vacuum source. The pressure difference being reversed, the piston moves towards the chamber (111) connected to the vacuum source. This type of motor is known per se, but usually used vacuum sources generally need a heat or electric source. The object of the invention is to create a vacuum source that does not require heat or electrical input.

As a source of vacuum that does not require artificially created energy, such as electricity, a Venturi tube placed in a pre-existing water stream is provided. There are many existing water currents that can be exploited. The advantage of a Venturi tube, besides using an energy source already present, but not exploited, lies in the fact that the air sucked to operate the air motor (100) is introduced into the water flow thus promoting its aeration and increasing the rate of oxygen in the water. This oxygen supply is favorable to the aquatic fauna and flora.

A Venturi tube (200) consists of a main channel of continuously varying diameter and a secondary channel called a vacuum tap. The main channel comprises placed one behind the other a convergent chamber (210) opening into a restriction (220) which continues with a divergent chamber (230). Taking vacuum (240) is provided at the restriction (220) in the case of a single Venturi. In the case of a multi-stage Venturi like those shown schematically in Figures 2 and 3 Vacuum taps (usually 2 or 3 extra vacuum taps) are placed one behind the other along the diverging part of the tube to exploit the entire vacuum zone.

A Venturi tube exploits the Bernoulli principle. If an incompressible liquid flows into a pipe, then its flow is constant. When the diameter of the pipe decreases, the speed of the liquid increases and its pressure decreases, while conversely, when the pipe widens, the fluid slows down and its pressure increases. Therefore, when a fluid flows into a Venturi tube from the inlet of the converging chamber (210) to the restriction, the diameter of the channel decreases and the initial pressure decreases as the velocity increases. At the end of the restriction (220), the diameter of the channel increases again and the pressure increases while the speed decreases. Due to the decrease of the pressure at the restriction (220), a depression is created which can be used to suck the fluid in the vacuum outlet. This vacuum outlet can be connected to the motor (100) to operate.

The Venturi tube is the heart of the invention. Its design must be done carefully to reach very low pressures which will give it a better suction flow. It must have a very short time of evacuation of the air volume of the cylinder of the machine, which will increase the power of the machine to which it is attached. It must be well secured to withstand the force of the water. As there are no moving parts, the Venturi tube requires very little maintenance. If the water pressure drops below the saturation vapor pressure, cavitation phenomena will occur which may damage the diverging part of the tube. We rely on the massive injection of air to eliminate the cavitation, that's why we must never cut the air intake of the Venturi, we must find a right balance between the diameter of the restriction and the absence of cavitation. The tube must be protected from debris carried by the water. The Venturi tube can be used as an integrated flow meter. It also has the advantage of not getting in the way of the flow of water as is the case with a turbine for example. It is only a particular form of pipe with a narrowing then a widening of the diameter. Pressure losses occur at the outlet of the tube and must be taken into account, because less pressure loss means an improvement in water flow, source of conventional hydraulic energy. The fish should not be allowed to pass through a tube Venturi because of the low pressures that hurt them, as it is already the case for hydraulic dams.

Experience has shown that the water accelerates substantially in the divergent portion of the Venturi tube when there is suction of air with respect to the speed of the water without suction of the air. Indeed, the air and the water cross the same section of the tube, the air passes in the form of microbubbles in the water and the volume which it occupies can be regarded as a reduction of the section of the pipe for the flow of water, but a decrease in the section corresponds to an acceleration of the fluid since the flow rate remains constant.

Numerical simulations were carried out with a single-acting Venturi tube 20 m long, 1 m in diameter, the diameter of the restriction being 0.45 m in diameter, the convergent angle of 34 ° , the angle diverges by 7 °.

The invention provides several locations for positioning the venturi tube. In a first embodiment, the Venturi tube is placed in a stream or a spillway, for example out of a dam. In a second embodiment, the Venturi tube is placed in a forced pipe placed between a source located in height and an outlet located in the open air. In all cases, the device of the invention uses the potential energy of the gravity water, either directly (in a dam pipeline) or is converted into kinetic energy for example in rivers or weirs.

In the first embodiment, the Venturi tube is placed in a stream in the open air and uses essentially the kinetic energy of the water. A first exemplary embodiment is diagrammatically shown in FIG. figure 2 , while a second example of realization is presented in Figures 13 to 15 .

In the example of the figure 2 , one or more Venturi tubes are placed on a weir in the open air. Spillways at the exit of the dams discharge the water without ever taking advantage of it, a weir in the form of a Venturi tube or equipped with venturi tube or venturi-effect structures would make the most of available resources.

Such a spillway, placed at the outlet of a dam or reservoir, constitutes a channel with a long, gentle slope in order to reduce the energy of the water before discharging it into a watercourse. . Thus, the speed of the water is moderate before entering each tube. In the example of the figure 2 the Venturi tubes are preferably arranged one behind the other, spaced apart and parallel to the flow. For reasons of simplification, it is preferable that they share the same air supply line. Another staircase configuration rather than slope, to achieve the same goal is possible, the tubes would be on the horizontal plane. In both cases, the strength of the dam water is reduced. Fig 2 shows a Venturi tube embedded in the channel, the inlet of the tube has a ramp inclined at an angle of about 45 ° to facilitate the passage of a portion of the water above the tube. This part of the water covers the tube and slides along a slab that protects the tube to reach the channel downstream. The other part of the water crosses the Venturi, it slows down strongly at the entrance and its static pressure increases. When the water enters the converging part, it accelerates strongly to the strangulation, thus generating a strong depression.

The same type of Venturi tube as before can be placed in a stream or in a marine current. These currents exist naturally and can be exploited without pollution. The installation of a Venturi tube in the rapids of the rivers makes it possible to benefit from the kinetic energy of the water. The system appears in its best condition for the respect of landscape and nature, because the Venturi tube will be totally immersed and not visible from the surface. It is firmly attached and parallel to the flow of water at high speed and its oxygen supply at depth will be important. In this embodiment, it is not necessary to provide penstocks or dams. So there is no negative aspect for the marine flora, but on the contrary, we help nature by aerating the water. In addition, it is possible to place several tubes behind each other or parallel to each other, thereby multiplying the energy to be extracted.

In the quest for maximum suction, one is tempted to use an increasingly tight bottleneck. It can result that the increasingly rapid water causes strong turbulence in the diverging portion which will completely slow the flow inside the tube, which will result in a bypass of the tube by the water, the tube then becomes inoperative!

In a second exemplary embodiment shown in Figures 13 to 15 the conventional Venturi tubes have been replaced by one or more hydrofoil type structures (450). When there are several hydrofoils, they are placed at a distance from each other in a battery either horizontally one above the other as on the Figures 13 to 15 , either vertically next to each other. Usually, hydrofoils are profiled fenders used not in the air but in the water to allow ship hulls to sift at a certain speed. In the present case, symmetrical hydrofoils (450) placed without inclination in the water stream have been chosen, for example NACA 0015 type profiles. Each hydrofoil, in its curved shape, causes on each of its faces first of all a narrowing of the available section for the flow of water between its leading edge (451) and its maximum thickness (452), then an increase between its maximum thickness (452) and the trailing edge (453). We see that a hydrofoil can be likened to Venturi tube. The restriction effect is clearly visible on the figure 13 , between two successive hydrofoils. By placing openings (454) on both sides (455, 456) of each hydrofoil, in the zone in which a depression occurs when immersed in a stream of water, it is possible to create empty leading inside the hydrofoil. In practice, the openings (454) will be placed in several rows parallel to the leading edge (451), and this in the area where there must prevail, during the circulation of water, a vacuum with respect to the atmospheric pressure. adapted to create a vacuum that can actuate the motor (100). Each hydrofoil is connected by a connecting tube (457) to a main air line (458) connected to the engine. During operation, the water circulating around each hydrofoil causes a depression on the convex part of each face, the air contained in the hydrofoil is sucked into the water by passing through the openings (454). A depression is created in the hydrofoil, a vacuum that is transmitted via the connecting pipe (457) and the main pipe (458) to the engine. To avoid backflush in the hydrofoils, there can be anti-return valves in the connecting tube (457) of each hydrofoil and / or at each opening (454). Thus, if an opening is in an area where the expected depression does not prevail, for example because the speed of the water is not as high as expected, the water will not enter the hydrofoil. As shown in figure 15 the hydrofoils preferably extend over the entire width of the water stream. The distance separating two successive hydrofoils of the same battery must be sufficient and can be determined by tests as a function of the flow rate of the water stream in which it is immersed.

It is also possible to place several hydrofoil batteries one behind the other as long as a minimum distance is maintained to allow the water to regain speed.

Hydrofoils are protected against cavitation by injecting air into the water.

Those skilled in the art understand that these hydrofoil type structures can be placed not only in open water currents such as streams or weirs, but also in closed conduits such as penstocks. In this case, the pipes will preferably have a rectangular section.

In the second embodiment of the invention, the venturi tube is placed in a pipe placed between a water reservoir placed at a height and an outlet placed lower than the water level of the reservoir. Typically, the pipeline will be located in a dam. The Venturi tube uses essentially the potential energy of the water due to the height difference between the source and the outlet.

A first variant embodiment of the invention applied to such a pipe is shown in FIG. figure 3 . The Venturi tube is placed in a pipe (311) of the dam (300). The depression created at the restriction (220) of the venturi tube serves to operate the air motor. This pipe may be created for the exclusive operation of the engine and have no other function, in which case it is not necessary to place it in a dam as shown here, but for example to place it as a simple penstock placed on the mountainside. However, it is conceivable to place the Venturi tube restriction in an existing pipe, especially well downstream of a turbine placed in the pipe.

A second embodiment is to use the restrictions already present in the pipes of the dams, but not used. In fact, the pipes, at the turbine level, are in themselves restrictions in which it is possible to place vacuum taps. Thus, it is observed at a hydraulic turbine cavitation phenomenon which usually should be avoided, because over time it can damage the turbine and the pipe. Cavitation occurs when the vacuum reaches the saturation vapor pressure of water, which depends on the temperature of the water. Stretching a liquid with increasing strength means applying negative pressure. The negative pressure thus applied eventually "breaks" the liquid and then a change of liquid phase -> gas resulting in the appearance of bubbles of water vapor. When the water passes through a diameter restriction, the pressure drops. The water boils if it reaches the saturation vapor pressure. It then forms multiple bubbles of steam. When the water regains pressure at the exit of the restriction zone, these bubbles burst against the walls of the tube. These burstings of vapor bubbles create small cavities on the surface of the pipe, this erosion condemns the latter to its destruction over time. It is this depression that is used in the present invention.

• les turbines à réaction dont le rotor provoque une différence de pression entre l'entrée et la sortie de la turbine ; et
• les turbines à impulsion dans lesquelles l'énergie potentielle de l'eau s'écoulant dans une conduite forcée est transformée en énergie cinétique par l'intermédiaire d'un jet d'eau qui agit directement sur les augets de la roue.

There are different types of hydraulic turbines depending on the height of the waterfall and / or the flow. Turbines are classified into two main categories:

• jet turbines whose rotor causes a pressure difference between the inlet and the outlet of the turbine; and
• impulse turbines in which the potential energy of the water flowing in a penstock is converted into kinetic energy by means of a jet of water which acts directly on the buckets of the wheel.

Examples of jet turbines are Francis turbines for medium to high waterfalls in which water penetrates radially and discharges axially, and Kaplan turbines for small waterfalls ( 2 to 25 meters high) and very high flows (70 to 800 m ³ / s). Bulb type turbines, in which water flows axially, are variants of Kaplan turbines. Among the turbines with action, one finds in particular the buckets with buckets of the Pelton type which are particularly well adapted to the great heights of fall (> 400 m) and the low flows of water (<15 m ³ / s).

In general, a reaction turbine is placed at the end of a forced pipe (311, 312, 313) and is extended by a suction pipe (411, 421) which opens lower in a leakage channel. The suction tube must be completely filled with the working fluid passing through it. It is made divergently to minimize the speed at the exit. Therefore, a suction tube is essentially a diffuser and must be designed correctly at an angle of about 8 degrees so as to prevent the separation of the flow from the wall and consequently to reduce the energy loss in the tube.

It must be avoided that the pressure upstream of the Venturi tube is too great when there is no turbine, because for example to lower one hundred bars to less than one bar, it is necessary to further narrow the passage of the water to the strangulation. This will result in high water velocity and severe turbulence in the diverging part of the tube. Such turbulence can slow down the flow of water and cause vibrations and noise.

The body of the turbine in the pipe is a restriction and the pressure of the water sometimes drops to saturation vapor pressure from where the appearance of cavitation on the blades of the turbine and out of the turbine. It is in this that the invention equates this construction with a gigantic Venturi tube embryo. If one or more openings in the pipe just below the turbine are used, a strong suction of air is created. Referring to the data provided by the company Mazzei, manufacturer of Venturi tube (http://mazzei.net/venturi_injectors/), it is possible to arrive at a volume of 50% water - 50% air. If we take an average water flow of 700 m ³ / s, we will have an air suction rate of the same order of magnitude. By multiplying this value by the number of turbines at the disposal of a dam (32 for the dam of the three gorges in China) the energy potential is phenomenal. The exact location of the openings depends on the type of turbine used. The vacuum tube takes on a new dimension since it becomes a source of energy in addition to a diffuser.

The water leaves the turbine in a helical movement, then flows in this form to the bottom of the diffuser tube. There is also a vortex cord in the middle, just below the turbine, which consists of undissolved oxygen and vapor. This rope is responsible for high-frequency fluctuation of the pressure which causes vibrations and noise and has a direct effect on the performance of the generators, some studies have shown that the injection of water or air by the medium of the shaft (hollow) of the turbine effectively reduces vibration and increases production at the same time. An air inlet through the Venturi tube as shown in figure 4 has the same effect.

The vacuum tube must be designed to slow down enough the speed of the water which is increased due to the massive injection of air. The new architecture of the dams will have to take into account in its design an effective vacuum tube in the light of the new order. The injection of air must not disturb the normal operation of the turbine.

The figure 4 presents a first example of this second variant embodiment. It represents the duct (312) of a dam at a Francis turbine (410). The water is introduced into the turbine radially via a spiral distributor (210) acting as a convergent chamber and then escaping axially in a suction pipe (411) which acts as a divergent chamber ( 230). Downstream of the turbine, there is a drop in pressure which can lead to a cavitation effect. According to the invention, it is intended to place on the periphery of the suction pipe (411), near the outlet of the turbine, one or more openings connected to the vacuum outlet (240). It is possible to place an open / close valve (242) in the air supply line acting as a vacuum plug for the Venturi tube. This valve is used to interrupt the air intake when necessary. It is also possible to place a check valve (241) to prevent water from flowing back to the air motor (100).

The same principle can be used for a Kaplan turbine.

The figure 5 presents a second example of the second variant embodiment. Here, the pipe (313) of the dam is provided with a bulb type turbine (420). Bulb type turbines are developments of Kaplan turbines whose blades are placed in the water current so that there is an axial hydraulic flow without change of direction, unlike Francis turbines. While in the traditional Kaplan turbine the alternator is placed outside the pipe, the alternator of a bulb type turbine is placed in a profiled envelope immersed in the flow. As shown in figure 5 , the conduit (313) in which the bulb-type turbine is located tapers at the end of the envelope directed towards the blades. Beyond the blades, the pipe widens again into a suction line (421). The impeller placed in the pipe and the narrowing at the end of the penstock (313) is a restriction (220) that can be used to form a Venturi tube. The end of the forced pipe (313) constitutes the convergent chamber (410) and the beginning of the suction pipe (421) the divergent chamber (230). According to the invention, it is intended to place on the periphery of this restriction one or more openings connected to a vacuum outlet (240).

The bulb turbines have a reversible operation, that is to say that the turbine is driven by the water that it flows in one direction or the other. That is why they are used especially in tidal power plants. The invention can be used in this type of dam.

A third embodiment of the second variant, represented on the figure 6 , plans to modify the nozzle of a Pelton turbine to create a Venturi tube. A Pelton turbine operates with a large vertical drop, but a low flow. The water is fed to the turbine by a forced pipe (314) from a reservoir placed much higher. It is projected in the radial plane on the buckets of the wheel by one or more nozzles located at the end of the penstock. The force of the water jet is adjustable using a needle of substantially conical shape. Traditionally, the needle is placed at the end of a control rod connected to a jack. The position of the needle in the nozzle is adjusted using the cylinder according to the desired flow rate. It is understood that a restriction is formed at the needle, which restriction is used in accordance with the invention to place a vacuum outlet. The solution adopted for this embodiment is different from the traditional Venturi tube, since it is not possible to inject the air from the nozzle, since the low pressure (high speed) region is not isolated from the surrounding air. To use a least invasive method possible, it is proposed to inject the air by a hollow needle, because it is isolated from the ambient air by the jet of water surrounding it. The inlet of the nozzle constitutes the convergent chamber (210), the space located between the front end of the needle and the nozzle (220). According to the invention, the control rod (431) and the needle (430) are hollow and form a channel for taking vacuum. The figure 7 shows a schematic perspective view of the needle (430) of the invention.

The needle may consist of a rear portion (432) integral with the control rod (431) and a front portion (433) as shown in FIG. figure 8 . The rear part of the needle and the control rod are hollow. A cylindrical section of the rear part of the needle (432) is threaded (male), while a cylindrical section of the front part (433) is threaded (female) in order to secure the two parts, a seal (434) can be interposed between them. The front portion (433) of the needle is pierced with numerous conduits (435) parallel to each other which open at the outlet of the nozzle. The air is injected into the water through these ducts. The front part is conical. This design allows water to flow along this conical shape as shown in figure 9 . An example of the geometric distribution of the ducts is visible on the figure 11 which shows a back view of the front portion (433) of the needle. It is preferable to provide one-way valves (436) to prevent backflow of water in the vacuum outlet when the needle or end of some ducts are in the high pressure areas. These unidirectional valves (436) can be placed in each of the ducts (435) of the front part of the needle. The figure 10 shows a section through such a unidirectional valve. A retaining plate (437) is placed upstream of the front portion (433) of the needle to hold the unidirectional valves (436) in place. This plate is preferably screwed on the front part (433). It is also possible to place a safety check valve (241) in the conduit of the control rod, for example at the entrance of this conduit, as shown in the Figures 2 to 6 or the figure 8 .

Finally, figure 12 schematically shows the connection of an air motor (100) to a vacuum outlet (240) from a Venturi tube according to the invention placed in a pipe of a dam (300) and to a crank-rod system (140) transforming the reciprocating motion of the piston into a circular motion to drive an alternator (not shown).

It is possible to place a filter (500) in the line supplying the engine (100) with ambient air. This filter removes the air sucked before injecting into the water after passing through the engine. It should be noted an important note, the engine itself becomes a suction pump through the displacement of the piston during the intake phase, the air admitted will be absorbed by the Venturi effect at the next suction. The air intake is also important. For example, VOCs (volatile organic compounds) can be sucked into the machine room and thus ensure an automatic renewal of the ambient air or in particularly polluted areas and pass it on filters before injecting it into the water. .

The invention has many advantages. By operating an air motor driving an alternator, it helps to increase the efficiency of a dam. It can be installed during the construction of the dam, or be easily installed in an existing dam.

The Venturi effect as described can operate a steam engine as well as a complicated rotary engine with compressed air or steam, the Tesla turbine being a good candidate for this system. The piston engine is a classic approach, but it can give an idea of the power that can be derived from such a system.

The atmospheric pressure provides the necessary force to operate the engine, it is important to have an idea about this force. The force and the pressure are connected by the formula P = F / S, where P is the pressure in Pa, F the force in N and S the surface of the piston in m ² . In other words, F = PS = P.π.D ^2/4 where D is the diameter of the piston.

The atmospheric pressure measured at sea level is 1.01325 · 105 Pa.

F becomes $$\mathrm{F\; becomes}F=0,7958\times {10}^5\times D^2$$

Since the atmospheric pressure is in first approximation constant, the force therefore essentially depends on the diameter of the piston raised squared and in the form of a function of the type f (x) = kx ² . The atmospheric pressure being substantially constant, if we want to increase its force, it is necessary to increase the surface of the piston, because it is the only variable parameter in our equation. The stroke of the piston and its surface determine the volume of air to be extracted. Suppose the dam depression reached 10,000 Pa with a suction flow of 200 m3 / s.

If we take a piston of 10 m diameter and a stroke of 0.5 m, the volume of air to extract is 78.56 m3, the evacuation time of this volume gives the linear velocity of the piston. But let's look at the force generated, 90% of the atmospheric pressure on the surface of the piston is 716,224 tons. This force reaches 2,864.88 tonnes if the piston is 20 m in diameter.

This small calculation gives an idea of the power of this engine, having a large torque and capable of improving the performance of a hydraulic power plant significantly. The engine then operates in implosion and not expanding like all known engines. The size of the machine is the image of the book, everything is big in a dam.

The routing of the air sucked through a pipe to the machine and then to the Venturi tube (vacuum pump) leads us to take into account the conductance of the pipes, because in our system, the pipes can be very long between the Venturi tube and machines. Conductance characterizes the ability of the pipeline to flow through the air and applies to all elements of the pump (pipe, valves, orifices, etc.). It is better to take into account the conductance of the pipes air routing for the calculation of the overall system yield which otherwise would be overestimated.

By injecting air into the water, it improves the quality of it which benefits the flora and fauna aquatic. Oxygen kills anaerobic bacteria and makes the fish breathe. The Venturi tube has no moving parts, it is very robust and does not require a large maintenance. The engine room can be placed away from the tube. The invention is ecological because it uses an existing energy that is otherwise lost, it is the invisible part of the hydraulic energy, the atmospheric pressure which we forgot the importance and the Venturi effect which in the end, is not an intuitive notion.

List of references:

100

Air motor
110 Double acting cylinder
111 First room
112 Second Chamber
113 Intake and exhaust valve of the first chamber
114 Intake and exhaust valve of the second chamber
120 Piston
130 Rod
140 Mechanism transforming the translation movement of the rod into a rotational movement

200

Venturi tube
210 Convergent room
220 Restriction
230 Diverging Room
240 Vacuum outlet
241 Check valve
242 Opening and closing valve

300

Barrage
311 Forced driving
312 Driving under duress
313 Forced driving
314 Forced driving

410

Francis Turbine
411 Suction tube
420 Bulb type turbine
421 Suction tube
430 Pointer of a Pelton Turbine
431 Pelton turbine needle control rod
432 Rear part of the needle
433 Front part of the needle
434 Gasket
435 Conduits
436 One way valves
437 Retaining plate
450 Hydrofoil type structure
451 Leading edge
452 Maximum thickness
453 Leakage
454 Openings as a vacuum outlet
455 1 ^st face
456 ^2nd face
457 Connecting tube
458 Main air line
500 Air filter

Claims (14)

Apparatus for generating a vacuum for operating an air motor (100), which engine is constituted a cylinder (110) inside which moves a piston (120) separating the cylinder into two chambers (111, 112) whose volume varies as a function of the displacement of the piston in the cylinder, the piston being provided with a rod (130) projecting from the cylinder at the end of one of the two chambers, each chamber being provided with at least one intake valve and at least one exhaust valve, a distributor being provided for alternately connecting the chambers (111, 112) to a vacuum source via their exhaust valves and at atmospheric pressure via their intake valves, characterized in that the device comprises at least one vacuum tap placed in a Venturi effect device (200). Device according to claim 1, characterized in that the Venturi effect device comprises a Venturi tube (200) placed in a pipe (311, 312, 313, 314) made in a hydraulic dam (300). Device according to Claim 2, characterized in that the vacuum port (240) of the venturi tube (200) is placed in a restriction (220) formed for this purpose in the pipe (311). Device according to claim 2, characterized in that the vacuum plug (240) of the Venturi tube (200) is placed in a restriction located downstream of a turbine (410) of the hydraulic dam, at the beginning of the driving of suction (411). Device according to Claim 2, characterized in that the vacuum outlet (240) of the Venturi tube (200) is placed at the end of the water supply pipe, or close to it, in the zone of low pressure in the vicinity of the blades of the turbine (420). Device according to claim 2 applied to a dam equipped with a Pelton turbine in which the flow from the water supply line is set to means of a needle attached to the end of a control rod and movable in a restriction, characterized in that the control rod (431) and the needle (430) are hollow and in communication one with the other, the end of the needle opposite the control rod being open, and the control rod serving as a vacuum outlet to the Venturi tube. Device according to claim 3, 4 or 5, characterized in that the vacuum outlet comprises a plurality of openings distributed around the periphery of the pipe. Device according to claim 7, characterized in that the openings are placed in the same radial plane. Device according to claim 1, characterized in that the Venturi effect device is placed in a stream of water in the open air, preferably in a watercourse or in a hydraulic dam weir. Device according to claim 1 or 9, characterized in that the device Venturi effect is constituted by at least one hydrofoil type structure (450), one or more openings (454) being made of the hydrofoil type structure, in a an area in which a depression is formed when the hydrofoil type structure is immersed in a stream of water, the hydrofoil type structure (450) being connected to a pipe (458) serving as a vacuum outlet for the engine, non-return valves being preferably provided at the junction (457) between each hydrofoil type structure and the pipe (458) and / or in each opening (454). Device according to the preceding claim, characterized in that several structures hydrofoil type (454) are placed at a distance from each other horizontally one above the other or vertically next to each other, preferably without inclination. Device according to claim 1, characterized in that an air filter (500) is placed upstream of the vacuum plug (240) of the Venturi tube. Device according to one of the preceding claims, characterized in that the device is provided with an air motor (100) connected to the vacuum socket (240) and consisting of a cylinder (110) inside which moves a piston (120) separating the cylinder two chambers (111, 112) whose volume varies as a function of the movement of the piston in the cylinder, the piston being provided with a rod (130) projecting from the cylinder at the end of one of the two chambers, each chamber being provided with at least one intake valve and at least one exhaust valve, the intake and exhaust valves of the same chamber being merging (113, 114), a distributor being provided for connecting alternatively the chambers (111, 112) at the vacuum source via their exhaust valves and at atmospheric pressure via their intake valves. Device according to the preceding claim, characterized in that the device is provided with a filter (500) placed in the air supply line of the engine (100).

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