EP0617227A1 - Air control system for hydropneumatic reservoir - Google Patents

Abstract

The air control system for a hydropneumatic reservoir (1) of the hydraulic (water) pipeline (2) comprises a chamber (6), a means (11, 12) for filling the chamber with water, a means (10, 13) for emptying the chamber of water, a means (14, 15, 16) for automatically introducing air into the chamber during emptying, a means (18, 19) for automatically injecting the air from the chamber into the reservoir during filling, and a control means (22) connected to at least one detector (23) for detecting that a threshold level of water contained in the reservoir has been exceeded and to the means for filling and emptying the chamber. If the detector indicates that there is an insufficient volume of air contained within the reservoir the control means triggers cycles filling/draining the chamber until the detector indicates that the volume of air in the reservoir has become sufficient. <IMAGE>

Description

The present invention relates to an air regulation system for a hydropneumatic reservoir equipping a hydraulic pipe which can be a distribution network for drinking water or irrigation, or a drainage network for waste water or chemical liquids.

The hydropneumatic reservoir can operate as a regulating reservoir (or hydrophore) to regulate the pumping pressure and ensure continuity of service in the pipeline, in a pressure range between a high threshold and a low threshold. When the high pressure threshold is exceeded, the pump (or one of the pumps) supplying the pipe is stopped. The regulation tank then supplies water to the pipeline. When the low threshold is reached, the pump is restarted to ensure sufficient pressure in the pipeline.

The hydropneumatic tank can also be used as an anti-ram tank in a hydraulic pipe in order to compensate for the effects of depression and overpressure caused for example by a stopping of a pump or a valve closing. The operation of such a tank is known in particular from French patent 2,416,417 (ROCHE).

An important problem for ensuring the proper functioning of the hydropneumatic reservoir lies in maintaining a constant volume of air in the reservoir. Indeed, the hydropneumatic tank contains, in operation, water or any liquid flowing in the pipe, and air trapped in the tank just above the water surface. The dissolution of air in water or vice versa the gassing of the liquid which can occur in certain cases create a variation of the volume of air trapped in the tank. It is therefore necessary to provide solutions making it possible to introduce air into the tank in the event of insufficiency, and to evacuate excess air from the tank in the contrary case.

In general, the air supply to the hydropneumatic tank is ensured by means of an air compressor or a outside air injector.

The main drawback of the air compressor is that the air introduced into the tank contains droplets or oil vapors sent by the compressor. If the presence of oil thus brought into the tank does not interfere with the evacuation of wastewater, it is not the same for the supply of drinking water.

Air injectors eliminate oil entrainment in the air injected into the hydropneumatic tank. They do not allow to compensate with exactitude the variation of the volume of air in the tank. Indeed, only experience has so far made it possible to fix the additional volume of air to be supplied to the tank, in particular as a function of the capacity of the tank and of the pressure of the water in the pipe, since the dissolution of air in contact with water depends on many factors. As a consequence, either an insufficiency or a surplus of air injected into the tank can occur, which cause a failure of correct regulation and, for the second case, air pockets which can be transported by the water in the pipeline and give birth to water hammer.

In addition, the conventional air injector suffers from other imperfections: the approximate use of the volume available in the injector for the water filling cycle (air injection into the tank) / emptying (introduction of the air in the device), the absence of means to protect the device's air intake valve against the risk of deterioration by contact with water (in particular waste water), the lack of concern for the quality of the air injected into the tank, and in the case of a pipe with submerged pump, the use of a drain siphon in the pipe which creates a loss of efficiency of the submerged pump due to the permanent evacuation of water pumped by the siphon, and each start of the submersible pump necessarily results in an injection of air into the tank even if such an injection is not requested.

The hydropneumatic reservoir generally comprises a hollow body called a balloon which communicates with the pipe to contain the liquid. The balloon may or may not have a bladder. For a balloon without bladder, it is necessary to provide a means of injection air in the flask to compensate for the dissolution of air in the liquid inside the flask.

Up to now, the detection of the exceeding of the threshold levels of the liquid in a balloon without a bladder is generally obtained using electrical contacts mounted on the side wall of the balloon through a window made on said wall. This solution has drawbacks from a practical point of view, in particular the problem of depositing impurities on the electrical contacts, the functioning of which may be impaired and difficulties or even impossibilities for modifying the settings.

Furthermore, an additional problem exists when the injection of air into the hydropneumatic tank is carried out via the water pipe. In fact, the quantity of air introduced into the tank via the pipe is not total, because part of the air injected into the pipe upstream of the tank is conveyed directly by the pipe downstream of the tank without entering the tank. This results in lower efficiency of the system, which is moreover difficult to determine, and the presence of air in the pipe downstream of the tank can pose serious problems from a hydraulic point of view.

The object of the present invention is to remedy the aforementioned drawbacks by proposing an air regulation system for a hydropneumatic reservoir which makes it possible to introduce an air volume corresponding precisely to the complement necessary for the reservoir.

The invention also relates to an air regulation system making it possible to supply a constant volume of air at each filling and emptying cycle of the system.

The invention further relates to an air regulation system whose air intake means is protected against deterioration or clogging in contact with the liquid.

Another subject of the invention is an air regulation system which supplies the hydropneumatic reservoir with air compatible with the liquid conveyed in the hydraulic pipe making it possible to avoid pollution of the liquid by the air introduced.

The air regulation system for a hydropneumatic reservoir of a hydraulic pipe according to the invention, comprises a chamber, means for filling the chamber with water, means for emptying water from the chamber, means for automatically introducing air into the chamber during emptying, and means for automatically injecting air from the chamber to the tank during filling. According to the invention, the system further comprises a control means connected to at least one detector for exceeding a threshold level of the liquid contained in the tank, and to the means for filling and draining water from the chamber. When the detector provides a signal corresponding to an insufficient volume of air in the tank, the control means initiates the filling / emptying cycle of the chamber until the detector indicates that the air volume in the tank has become sufficient again.

Thanks to the invention, the problem of dissolving air in contact with water in the regulation tank can be precisely controlled.

According to one embodiment of the invention, the top of the chamber can be fitted with a liquid level detector, connected to the control means to indicate the end of filling of the chamber. The control means can then trigger the chamber emptying phase at this precise moment. Similarly, it is possible to equip the lower bottom of the chamber with a liquid level detector connected to the control means, to indicate the end of the emptying to allow the control means to initiate the filling phase of the chamber. Thus, the volume of air injected into the tank is constant for each filling / emptying cycle of the system chamber and, above all, the filling / emptying phases of the chamber can follow one another without dead time as long as the lack of air persists.

Advantageously, the chamber of the air regulation system comprises a substantially vertical tube, the lower end of which opens into the upper wall of the chamber, the upper end of the tube being provided with a solenoid valve for the admission of the in the room. The vertical tube acts as a compression chamber between the air intake solenoid valve and the surface of the liquid in the chamber preventing the liquid from reaching the solenoid valve air intake, which protects the solenoid valve against possible deterioration in contact with the liquid, especially in the case of waste water or chemical liquids.

Preferably, the air intake solenoid valve of the system is connected to one end of a pipe, the other end of the pipe being placed in the immediate vicinity of the surface of the water to be pumped, so that the air injected by the system into the tank is compatible with the water carried by the pipe. This point is particularly important for a drinking water supply pipe in order to avoid any risk of pollution of the water by the injected air. In fact, atmospheric air in the vicinity of the air intake solenoid valve may contain harmful particles which can deteriorate the quality of the water.

According to the invention, the hydropneumatic reservoir may further comprise a hollow bar made integral with the reservoir and plunged vertically downward into the reservoir. The lower end of the hollow bar is closed so as to form a longitudinal cavity isolated from the interior of the tank by the wall of the hollow bar. In the bar cavity is (are) housed the threshold level overshoot detector (s).

Preferably, the height of the detector (s) in the hollow bar can be adjusted so as to allow the modification of the threshold levels of the liquid in the hollow body of the reservoir as required. The detector (s) can be of the capacitive or equivalent type which provides different signals when there is presence or absence of the liquid at their height.

Thanks to the invention, the problem of resistance to pressure, sealing and deposition of impurities known for conventional detection means is eliminated and the reservoir can be easily adapted to regulate the pressure of the liquid to different ranges according to the needs linked to the nature of the pipeline and its new desired hydraulic regime. In addition, you can choose hollow bars of small diameter resistant to high pressures.

According to another embodiment of the invention, the system comprises an air trap associated with the hydropneumatic reservoir in the case where air is injected into the tank through the pipeline. The air trap makes it possible to suppress the air flows in the pipe downstream of the tank, which eliminates the problems which can result therefrom and returns total efficiency to the system.

• les figures 1A, 1B montrent schématiquement le fonctionnement du système de l'invention,
• les figures 2 et 3 représentent deux variantes du système par rapport au mode illustré sur les figures 1A et 1B,
• la figure 4 est une variante du système pour le cas d'une pompe immergée sans clapet de retenue associé à la pompe,
• la figure 5 illustre une autre variante du système de l'invention avec la chambre séparée de la canalisation,
• la figure 6 est un schéma montrant un réservoir hydropneumatique de l'invention avec les détecteurs de niveau seuil immergés dans le liquide,
• la figure 7 est un schéma montrant un réservoir hydropneumatique selon l'invention avec un tube creux pour les détecteurs de niveau seuil,
• la figure 8 est un schéma montrant une variante de réalisation de l'invention,
• la figure 9 est un schéma montrant une autre variante de réalisation de l'invention,
• la figure 10 est un schéma montrant une autre variante de réalisation de l'invention,
• la figure 11 est une vue en coupe selon XI-XI de la figure 10,
• la figure 12 est un schéma montrant une autre variante de réalisation de l'invention,
• la figure 13 est une vue en coupe selon XIII-XIII de la figure 12,
• la figure 14 est un schéma montrant un piège à air selon l'invention,
• la figure 15 est un schéma montrant un autre piège à air selon l'invention, et
• la figure 16 est un schéma montrant un dispositif de sécurité selon l'invention.

The invention will be better understood and other advantages will appear on reading the detailed description of a few embodiments taken on a non-limiting basis and illustrated by the appended drawings, in which:

• FIGS. 1A, 1B schematically show the operation of the system of the invention,
• FIGS. 2 and 3 represent two variants of the system compared to the mode illustrated in FIGS. 1A and 1B,
• FIG. 4 is a variant of the system for the case of a submerged pump without a check valve associated with the pump,
• FIG. 5 illustrates another variant of the system of the invention with the chamber separated from the pipeline,
• FIG. 6 is a diagram showing a hydropneumatic reservoir of the invention with the threshold level detectors immersed in the liquid,
• FIG. 7 is a diagram showing a hydropneumatic reservoir according to the invention with a hollow tube for the threshold level detectors,
• FIG. 8 is a diagram showing an alternative embodiment of the invention,
• FIG. 9 is a diagram showing another variant embodiment of the invention,
• FIG. 10 is a diagram showing another variant embodiment of the invention,
• FIG. 11 is a sectional view along XI-XI of FIG. 10,
• FIG. 12 is a diagram showing another variant embodiment of the invention,
• FIG. 13 is a sectional view along XIII-XIII of FIG. 12,
• FIG. 14 is a diagram showing an air trap according to the invention,
• FIG. 15 is a diagram showing another air trap according to the invention, and
• FIG. 16 is a diagram showing a safety device according to the invention.

As shown in FIGS. 1A and 1B, the air regulation system is intended for a hydropneumatic tank 1 in the form of a balloon, without bladder, the lower part 1b of which is connected to a hydraulic pipe 2. The system comprises a air injection device installed upstream of the tank 1 in the pipe 2 and downstream of a supply pump 3 submerged or not in a water reservoir 4 which can be a well, a borehole or a tarpaulin. A check valve 5 is associated with the feed pump 3. It is the foot valve of this pump or a valve installed downstream and which prevents any return of water. The valve 5 may not be provided, in particular if a water level detector 26 mentioned below is installed.

The air injection device comprises a chamber 6 formed by a section of pipe 2, the section 6 being delimited in the direction of the normal flow 7 of water in the pipe 2, on the one hand at its end downstream by a non-return valve 8 mounted on the pipe 2 upstream of the tank 1, and on the other hand at its upstream end by a water level 9 defined by a water evacuation solenoid valve 10. L the upstream end of the section forming chamber 6 is at a lower level than the downstream end of the section. A pipe 11 connects the pipe 2 downstream of the non-return valve 8 to the section 6 in order to allow the filling of the chamber 6 with water. An electro-valve 12 is installed on the pipe 11 to control the filling of the chamber 6 with water via the pipe 11. The evacuation electro-valve 10 constitutes a means of emptying the chamber 6, the evacuated water being possibly collected in a discharge tank 13.

The air injection device further comprises an air intake solenoid valve 14 connected on the one hand to the chamber 6 by means of a vertical tube 15 opening into the upper wall at the top of the chamber 6, and secondly to a pipe 16 which takes air in the vicinity of the water surface 17 of the water reservoir 4. Thus, the air introduced into the room 6 via the pipe 16, the inlet solenoid valve 14 and the vertical tube 15 is compatible with the water conveyed in the pipe 2 (in particular free of pollution). The upper wall of the chamber 6 communicates with the lower part 1b of the hydropneumatic tank 1 via a pipe 18 fitted with a non-return valve 19.

The principle of injecting air into the tank 1 is relatively simple. The feed pump 3 stops, the associated valve 5 preventing the water contained in the pipe 2 downstream of the pump 3 from escaping through the latter. If there is a lack of air in the tank 1, the evacuation solenoid valve 10 opens to drain the chamber 6 until the drain level 9 is reached. At the same time as the opening of the evacuation solenoid valve 10, the air intake solenoid valve 14 is opened in the chamber 6. The non-return valve 8 prevents the downstream water contained in the pipe 2 to pass into the chamber 6. The same is true for the non-return valve 19 which prevents the water from the reservoir 1 from entering the chamber 6. During the emptying, the filling electro-valve 12 stays closed.

At the end of emptying, the chamber 6 is filled with air as illustrated in FIG. 1A. The solenoid valves for water evacuation 10 and the air inlet 14 are then closed and the filling solenoid valve 12 is opened. The pipe 11 then makes it possible to supply the chamber 6 with water contained in the pipe 2 downstream of the non-return valve 8. The air contained in the chamber 6 is expelled through the pipe 18 towards the tank 1 (FIG. 1B). The air bubbles 20 thus created in the water contained in the tank 1 go up to the surface 21 which represents the separation between the water and the air in the tank 1. The air thus introduced into the tank 1 thus contributes to the increase in the air volume of the tank. At the end of the chamber 6 filling phase, if the volume of air introduced is not sufficient, the chamber 6 emptying and filling cycle begins again.

According to the invention, the air regulation system comprises a control means 22 which is connected to at least one detector 23 via a link 24 to indicate the exceeding of a threshold level in the tank 1 by the water surface 21 for a given state (pump stop for example). The control means 22 is also connected to the solenoid valves for water discharge 10, water filling 12 and air intake 14 in order to control their openings and closings. for the operation of the filling / emptying cycle of the chamber 6 as a function of the signal emitted by the detector 23.

In the case illustrated in FIGS. 1A and 1B, the water level 21 in the tank 1 when the pump 3 stops is higher than the level of the detector 23 which defines the water level in the tank 1 at stop pump 3 for correct inflation of tank 1. This means that the volume of air contained in tank 1 becomes less than the normal volume required, due to the dissolution of air in water. The detector 23 immersed in water then emits a signal to the control means 22 which triggers the emptying / filling cycle of the chamber 6 of the device as previously described. When the volume of air supplied by the device to the tank 1 is sufficient to compensate for the loss of the air volume in the tank 1, the water level 21 in the tank reaches the level of the detector 23 which is no longer submerged in water. The corresponding signal sent by the detector 23 to the control means 22 allows the latter to stop the filling / emptying cycle of the device. When the supply pump 3 starts to supply the pipe 2, the solenoid valves for water discharge 10, water filling 12 and air intake 14 are and remain closed.

In order to increase the accuracy of the volume of air introduced into the reservoir 1 at each filling / emptying cycle of the chamber 6 of the device but above all so that the filling / emptying phases of the chamber 6 follow one another without dead time as long as the lack of air persists, the chamber 6 can optionally be fitted with an upper detector 25 at the top of the chamber in the vertical tube 15 and with a lower detector 26 to indicate the level of emptying 9 of the chamber 6. The detectors level can be simple electrical contacts which emit different signals in the presence and absence of water at their level and which are connected to the control means 22.

FIG. 2 shows a variant of the system which differs from the previously described mode by its method of filling the chamber 6 and injecting air into the tank 1. According to this embodiment, in fact, the filling of the chamber 6 takes place directly using of the pump 3. The air contained in the chamber 6 is injected through the non-return valve 8 into the pipe 2 downstream of the valve 8, the pipe 2 conveying the volume of air injected into the tank 1.

Chamber 6 is formed by a section of pipe 2 which forms an elbow. The vertical part of the bent section is part of the pumping discharge line of the pipe 2. The vertical tube 15 connecting the air intake solenoid valve 14 and the top of the chamber 6 forms a compression chamber which traps air preventing the water conveyed in the chamber 6 from coming into contact with the inlet solenoid valve 14. According to this embodiment, each filling of the chamber 6 requires starting the associated pump 3.

The mode illustrated in FIG. 3 is substantially identical to the mode illustrated in FIG. 2 except as regards the shape of the chamber 6 of the system. Instead of having a bent section, the chamber 6 can simply be constituted by an inclined section of the pipe 2.

FIG. 4 shows a simplified embodiment of the system of the invention. The check valve 5 associated with the pump 3 is removed. In this case, stopping the pump 3 and opening the air intake solenoid valve 14 brings the water level 9 back into the pipeline at the same level as the surface 17 of the pumped water. Compared to the embodiment illustrated in FIG. 2, there is no longer any need to provide an evacuation solenoid valve 10 nor a lower level detector 26 since, for sure, the emptying level 9 coincides with the surface 17 pumping water. The filling of the chamber 6 is carried out by means of the pump 3 and the air admitted by the solenoid valve 14 (which is now closed) into the chamber 6 is expelled into the tank 1 via the non-return valve. return 8 and part of the pipe 2 upstream of the tank 1. The chamber 6 is emptied by stopping the pump 3 and opening the air intake solenoid valve 14 but only, as before, if there is a lack of air in the tank 1.

In the case of deep structures, the height of line 2 thus drained may be too large to inject a correct volume of air into the reservoir 1. It then suffices to close the solenoid valve 14 for air intake, ie after a predetermined time after stopping the pump 3, or when the water level of the lower detector 26 placed at a predetermined height of the pipe 2 exceeds it. The drain level 9 ′ is then greater than the surface 17 of pumping water. We can thus adjust the volume of the chamber 6 of the device.

Instead of taking a section of the pipe 2 as a chamber for the air injection device, it is possible to provide a chamber 6 separate from the pipe 2 as shown in FIG. 5. It is thus possible to operate the device of the invention independently of the operating state of the pump 3 associated with the pipe 2 (FIG. 1A), whereas in the case where the chamber 6 is an integral part of the pipe 2, the device can only operate in relation to the pump 3. The operation of the device according to Figure 5 is comparable to that illustrated in Figures 1A and 1B.

According to FIG. 5, the chamber 6 is produced in the form of a balloon, the upper wall of which communicates with the vertical air intake tube 15 and the air injection tube 18 towards the tank 1 via the check valve. -back 19. The filling and emptying of the chamber 6 is carried out by means of a two-way solenoid valve 27, the first 27a is connected to the filling line 11 and the second 27b connected to the line evacuation 28. The solenoid valve 27 communicates with the interior of the chamber 6 via a vertical tube 29 passing through the bottom of the balloon forming the chamber 6 and the upper end of which can exceed the bottom of the chamber by a height h. It will be appreciated that the emptying level 9 of the chamber 6 is defined by the height of the upper end of the vertical tube 29. It is therefore possible to adjust the useful volume of the chamber for the injection of air by varying the height h of the vertical tube 29. Advantageously, an upper detector 25 can be provided in the vertical air intake tube 15 and a lower detector 26 at the level secured to the upper end of the vertical communication tube 29. The air injection pipe 18 can be connected directly to the tank or to the pipe 2 in upstream of the reservoir.

According to a particular embodiment of the invention illustrated in FIG. 6, the regulation system comprises a vertical or horizontal cylindrical tank 1, the ends of which are slightly domed (balloon), an air compressor 30 and electrical contacts 23a, 23b assuming that it is a hydrophore (or regulation) tank for pumping on demand (or overpressure) with a single pump, for example delivering in line 2. However, what is specified below can be generalized, with minor modifications, to hydrophoric tanks fitted to installations comprising several pumps and to anti-ram tanks.

The air compressor 30 communicates with the interior of the balloon 1 via an air line 18 opening into the upper wall 1a of the balloon 1.

The upper 23a and lower 23b detectors set the predetermined high threshold and low threshold levels for the liquid in the tank 1 in order to regulate the flow of the liquid in the pipe 2. The high threshold and low threshold levels in the tank 1 correspond to upper and lower limit pressures defined for the flow of the fluid in the pipe 2. The detectors 23a and 23b are connected on the one hand to the air compressor 30 via a link 31 and on the other hand via a connection 32 to one or more pumps, not shown, which supply line 2 with liquid.

In normal operation of the regulation system, the tank 1 is partly filled with the liquid flowing in the pipe 2. The level 21 of the liquid in the tank should be between the high threshold and low threshold levels determined by the detectors 23a and 23b. When the level 21 becomes higher than the height of the detector 23a, which corresponds to a pressure of the liquid which exceeds the determined upper pressure of the network, the detector 23a emits a signal to the control means 22 which stops the pumping supplying the pipe 2. The continuity of the supply of the pressurized liquid is then ensured by the liquid contained in the tank 1 which feeds via its lower part 1b the pipe 2. The tank 1 is emptied therefore, and when the level of the liquid 21 becomes lower than the height of the lower detector 23b, which means that the pressure of the liquid in the line 2 becomes lower than the authorized lower limit, the detector 23b sends a signal to the control means 22 which delivers a start signal via link 32 to start the pump. Then, again, the pressure in the line 2 increases and the level of the liquid 21 in the balloon 1 increases. In this way, the pressure of the liquid in line 2 can be regulated.

The operation of the regulation system as what has just been described requires that the balloon 1 be correctly inflated, not only for its initial inflation, but also to compensate for a reduction in the volume of air inside the balloon 1 due to dissolving air in the liquid.

The initial inflation of the balloon determines the upper and lower limit pressures of the network corresponding to the height of the balloon detectors 23a and 23b. An incorrect initial inflation of the balloon would therefore cause a shift in the range of allowable pressures either towards higher values or towards lower values, which could be harmful for line 2 and possibly for users.

Starting from a good inflation of the balloon, when the pump stops (is stopped for an anti-ram tank), if the level 21 of the liquid is higher than the upper threshold level indicated by the detector 23a, this means that the inflation of balloon 1 has become insufficient. The detector 23a immersed in the liquid sends a signal to the air compressor 30 via the control means 22 and the connection 31. The air compressor 30 starts and sends compressed air to the balloon via line 18 until the level 21 of the liquid reaches the level of the detector 23a, which then emits a stop signal to the air compressor 30 via the control means 22 and the link 31. The inflation of the balloon is restored correctly.

The regulation system described above presents the detectors 23a and 23b fixed to the interior wall of the tank 1 and exposed to the liquid which may contain impurities. The deposition of impurities on the detectors 23a and 23b can deteriorate their long-term operation. In addition, the fixing of the detectors 23a and 23b requires the opening of windows through the side wall of the balloon 1 and there is no possibility of easy modifications of the position of these detectors, therefore of the adjustments.

FIG. 7 illustrates a regulation system of the invention in an operating mode comparable to the system described above and illustrated in FIG. 6. The regulation system comprises a hollow bar 33 plunged vertically inside the balloon 1 from its upper part 1a. The lower end 33a of the hollow bar 33 is closed in order to completely isolate the interior of the hollow bar 33 from the interior of the balloon 1. Taking the same hypothesis as above, that is to say a hydrophore reservoir and a single pump, two level detectors 23a and 23b are arranged inside the hollow bar 33 with a predetermined height difference defining high and low threshold levels of the liquid in the balloon 1.

Preferably, the hollow bar 33 is made in tubular form and mounted coaxially with the balloon 1. The central tube 33 is made from a non-metallic material to allow the installation of detectors 23a, 23b of the capacitive type or equivalent. The central tube 33 can also be metallic if detectors other than of the capacitive type and capable of acting through metallic walls are used. Advantageously, the sensors 23a and 23b can be adjusted in height inside the central tube 33 in order to adapt the balloon 1 to the pressure requirements of the pipe 2. To make the sensors 23a and 23b adjustable in height, it is possible to use rods immersed in the tube 33 and on which the detectors are mounted. It is also possible to envisage stops at determined heights in the tube for setting the detectors. The detectors 23a and 23b are protected by the wall of the central tube 33 against deposits of impurities conveyed by the liquid.

The balloon 1 may include a valve 34 at its upper wall 1a which allows air to be discharged from the inside of the balloon 1 to the outside, this in order to avoid an undesirable overpressure at inside the balloon 1. This can be the case for example if the liquid gives off a gaseous mixture, for example air, in the balloon.

The operation of the system illustrated in FIG. 7 for regulating the pressure of the pipe is identical to the operation of the system of FIG. 6 and will not be described further.

Of course, as indicated above, the number of level detectors used for the tank can vary as required. For example, in the case where the tank is used as an anti-ram balloon, one can be satisfied with a single level detector, such as the high threshold level detector 23a inside the central tube 33. The triggering of the air compressor 30 by the detector 23a in case of insufficient air volume in the balloon 1 is produced according to the same principle as above.

For the other embodiments of the invention which are illustrated in FIGS. 8 to 13, the system can operate both for regulating the pressure in the pipe 2 and for avoiding the pressure surge in the pipe 2. Likewise, a valve 34 can be provided on the upper wall 1a of the balloon 1 if necessary. Since the operating principles of the various embodiments of the invention are comparable to each other, we will only describe their difference.

According to the mode illustrated in FIG. 8, the lower part 1b of the balloon 1 is provided with an airtight valve 35 which controls the communication between the balloon 1 and the pipe 2. An evacuation pipe 36 is provided between the lower part 1b of the balloon and the valve 35. The evacuation pipe 36 is connected to a drain valve 37. Such equipment facilitates the initial inflation of the balloon 1, either when the tank is put into service, or after a stop extended installation (in irrigation for example). To do this, the valve 35 is closed and the drain valve 37 is opened. When the balloon 1 is emptied, the drain valve 37 is closed and the balloon 1 is inflated, by means of the pipe 18, opening in its upper part 1a, with compressed air coming from the air compressor 30 or from a compressed air bottle, up to the desired pressure corresponding to the correct inflation of the balloon. Then stop the injection of air and open the valve 35 to re-establish communication between the tank 1 and the pipe 2.

The equipment which has just been described can be used for the other embodiments described and illustrated. It suffices to provide an orifice at the top of the tank to allow the initial inflation of the tank using a compressed air bottle.

The reservoir according to FIG. 9 differs from that illustrated in FIG. 7 in the design of the means for injecting the air into the balloon 1. Instead of having an air compressor 30 which risks introducing droplets or oil vapors in the air injected into the balloon 1, an air injection device 38 is used which is connected on the one hand to the pipe 2 via a pipe 39 and on the other hand either to the lower part of the balloon 1 or to the pipe 2 upstream of the balloon 1 via a pipe 18 provided with a non-return valve 19. The device 38 makes it possible to introduce air into the balloon 1 by means of emptying and filling cycles an auxiliary tank or chamber 6 of the device. The filling of the auxiliary tank 6 with the liquid expels the air at the upper part of the auxiliary tank of the device in the balloon 1 via the connection line 18, the non-return valve 19 preventing the return of the air and the liquid in the auxiliary tank 6.

As illustrated in FIG. 10, the regulation system comprises an air injection device 40 which is integrated into the pipe 2 upstream of the balloon 1 in order to inject the air, if necessary, into the balloon 1 via line 2. Some embodiments of the air injection device 40 have already been described previously and illustrated in FIGS. 1 to 4.

In the lower part 1b of the balloon 1, the pipe 2 has an inlet 41 and an outlet 42 for the liquid in the balloon 1. The inlet 41 can be extended vertically upwards by a pipe 43 projecting inside the balloon 1. The purpose of such an extension 43 is to create an air trap injected into the liquid by the air injection device 40. The air conveyed by the liquid introduced into the balloon 1 via the inlet 41 rises in the balloon 1 to the separation surface 21 between the air and the liquid contained in the balloon 1 or terminates directly in the air zone if this surface 21 is located below the top of the pipe 43. This configuration therefore avoids any loss of useful volume in the balloon 1.

FIG. 12 shows an alternative embodiment of the air trap constituted by the inlet 41, the possible vertical extension 43 and the outlet 42 for the liquid at the lower part 1b of the balloon 1. The difference in structure of the air trap between the modes illustrated in FIGS. 10 and 12 is better illustrated by FIGS. 11 and 13.

In order not to create a pressure drop in line 2, it is preferable to have the same cross section for inlet 41 as for line 2 immediately upstream of the tank 1. It is the same for the straight section of the outlet 42 located at the bottom of the tank 1 relative to the section of the pipe 2 immediately downstream of the tank 1. As illustrated in FIG. 11, the inlet 41 and the outlet 42 are constituted by two compartments of a tubular pipe 44 separated by a central wall 45. The section of the tubular pipe 44 advantageously corresponds to the sum of the sections of the pipe 2 immediately upstream and downstream of the tank 1. According to FIG. 13, the inlet 41 and outlet 42 are independent of each other and are constituted by a simple bend in the pipe 2 opening into the lower part 1b of the balloon 1.

Of course, the design of an air trap is only used for the case where the injection of air into the balloon 1 is carried out via the pipe 2. Apart from the structures illustrated in the figures 10 to 13, the air trap can take various forms, it suffices that the air introduced into the balloon 1 through the inlet 41 cannot escape with the liquid at the outlet 42.

In general, to carry out air trapping in the balloon 1, the inlet 41 with possibly its extension 43 must be located at a level above the outlet 42.

Figures 14 and 15 show two other embodiments of the air trap. According to FIG. 14, the inlet 41 opens into the side wall of the balloon 1 above the bottom of the balloon, and the outlet 42 opens out into the bottom of the balloon. This mode is particularly suitable for wastewater, because tows or other long bodies conveyed by the liquid in the pipe 2 risk being wound around the extension 43 of the inlet 41 illustrated in FIGS. 10 to 13.

The air traps described above require that all of the pumped water pass through the balloon. In the case of waste water, they risk causing deposits at the bottom of the tank, because all the materials transported in the waste water pass through the tank 1. The problem can be solved by the mode illustrated in Figure 15. The pipeline 2 has a part 2a with three openings and located immediately below the balloon 1. The upper opening of part 2a opens into the lower part 1b of the balloon 1. The liquid arrives through the intermediate opening of part 2a and leaves through the lower opening of this part of the pipe. The intermediate and lower openings are connected by a vertical or inclined pipe section of an angle ϑ at least equal to 45 ° relative to the horizontal.

The air trap according to FIG. 15 therefore makes it possible to limit the quantity of materials transported by the waste water which pass through the balloon 1.

In order to prevent the total accidental emptying of the balloon 1 and the air leakage from the balloon to the pipe 2, a safety device can be provided at the lower part 1b of the balloon at the outlet 42 for the liquid.

As illustrated in FIG. 16, the safety device comprises a float 46 made of light material, such as foam or plastic, a flexible membrane 47 and flexible lines 48. The flexible membrane 47 is fixed to the float 46 by the flexible lines 48. The lower part 1b of the balloon has an opening 1c closed by a horizontal plate 49 fixed to the balloon 1 by means of bolts. The plate 49 has an opening communicating with the outlet 42 for the liquid, on this opening being provided a grid 50.

The float 46 on which the Archimedes' push of the liquid acts keeps the flexible membrane 47 fixed upward curved at the center of the grid 50. The water can therefore pass through the outlet 42. When the water level drops excessively in the balloon 1, the float 46 lowers and the membrane 47 is applied to the grid 50 and to the plate 49, which prevents the complete emptying of the balloon 1. On the underside of the float 46 can be provided lugs 51 allowing the pressure of the liquid to be exerted uniformly on the membrane 47 even when the float 46 is in contact with it.

Claims (24)

Air regulation system for a hydropneumatic tank (1) of a hydraulic pipe (2), comprising a chamber (6), a means of filling water (11, 12; 3; 11, 27a) of the chamber , means for draining water (10, 13; 27b, 28) from the chamber, means for automatically introducing air (14, 15, 16) into the chamber during emptying, means for automatic injection (18, 19; 8) of the air from the chamber to the reservoir during filling, characterized in that it further comprises a control means (22) connected to at least one overshoot detector (23; 23a, 23b) of a threshold level of the water contained in the tank and in the means for filling and emptying the chamber, and that if for a given state, the detector indicates an insufficiency of the volume of air contained in the tank for In this state, the control means initiates filling / emptying cycles of the chamber until the detector indicates that the volume of air becomes sufficient in the r reservoir. System according to claim 1, characterized in that it comprises an upper water level detector (25) placed at the top of the chamber (6) and connected to the control means (22) to indicate the end of filling of bedroom. System according to claim 2, characterized in that it comprises a lower water level detector (26) disposed at the lower bottom of the chamber and connected to the control means (22) to indicate the end of the emptying of the bedroom. System according to one of the preceding claims, characterized in that the chamber (6) comprises a vertical air introduction tube (15), the lower end of which opens at the top of the chamber and the upper end of which communicates with an air intake solenoid valve (14), the vertical tube constituting a compression chamber between the air intake solenoid valve and the water in the chamber. System according to claim 4, characterized in that the upper detector (25) is mounted in the vertical tube (15). System according to one of the preceding claims, characterized in that it comprises a pipe (16), one end of which is situated in the vicinity of the surface (17) of the pumped water (4) and the other end of which communicates with the means for automatically introducing air into bedroom. System according to one of the preceding claims, characterized in that the chamber (6) is formed by a pipe section (2), delimited in the direction of the normal flow (7) of the liquid in the pipe, of a part at its downstream end by a non-return valve (8) mounted on the pipe upstream of the tank (1), and on the other hand at its upstream end by a drain level (9) defined by the draining means, the dimension of the upstream end of the section being lower than that of its downstream end. System according to claim 7, characterized in that the automatic air injection means injects a predetermined volume through the non-return valve (8) into the pipe (2) upstream of the tank (1) or directly into the lower part of the tank by means of a pipe (18) provided with a non-return valve (19). System according to claim 7 or 8, characterized in that the filling means in the chamber is constituted either by a solenoid valve (12) mounted on a filling pipe (11) one end of which opens into the pipe (2) downstream of the non-return valve (8) and the other end of which opens into the chamber (6), or by a pump (3) which normally supplies the pipe (2). System according to one of claims 1 to 6, characterized in that the chamber (6) is constituted by a balloon separated from the pipe (2), and that the filling and emptying means are constituted by a solenoid valve with two channels (27) communicating with the chamber (6) via a vertical tube (29) passing through the lower wall of the chamber, the vertical tube (29) being able to extend beyond the bottom of the chamber by an adjustable height (h) inside the room. System according to one of the preceding claims, characterized in that it comprises a hollow bar (33) made integral with the hydropneumatic tank (1) and plunged vertically towards the low in the tank, the lower end (33a) of the bar being closed and thus delimiting a cavity in the hollow bar, and that the overshoot detector (23a, 23b) is housed in the cavity of the hollow bar. System according to claim 11, characterized in that the overflow detector (23a, 23b) is arranged in the cavity of the hollow bar in an adjustable manner in height. System according to claim 11 or 12, characterized in that the overshoot detector is of a capacitive type (or equivalent) which provides different signals in the presence or absence of the liquid at its level. System according to one of claims 11 to 13, characterized in that the reservoir (1) is substantially cylindrical vertical or horizontal closed on two sides, and that the hollow bar (33) is in tubular form made integral with the upper wall ( 1a) of the tank. System according to one of the preceding claims, characterized in that it comprises a valve (34) at the upper part (1a) of the tank (1) making it possible to evacuate the air in the event of overpressure in the tank. System according to one of the preceding claims, characterized in that it comprises a valve (35) controlling the liquid communication between the pipe (2) and the lower part (1b) of the tank, and that it comprises a pipe 'drain (36) one end of which opens into the lower part of the tank above the valve (35) and the other end of which comprises a drain valve (37). System according to one of the preceding claims, characterized in that the automatic injection means (18, 19; 8; 40) injects air into the tank (1) via the pipe (2), and that the connection between the lower part (1b) of the tank and the pipe has an air trap (41, 42, 43; 2a). System according to claim 17, characterized in that the air trap consists of an inlet (41) for the liquid opening into the lower part (1b) of the tank and which can be extended upwards by a pipe (43), and an outlet (42) for the liquid, also opening out at the bottom of the tank, the respective cross section of the inlet and outlet being substantially identical to the cross section of the pipe (2) immediately upstream and downstream of the reservoir. System according to claim 17, characterized in that the air trap consists of an inlet (41) for the liquid emerging in the lower part (1b) of the tank and by an outlet (42) for the liquid also opening in the part bottom of the tank, the inlet being located above the outlet for the liquid. System according to claim 17, characterized in that the air trap consists of a pipe part (2a) situated below the lower part (1b) of the tank, said pipe part having an upper opening opening into the lower part of the reservoir, an intermediate opening through which the liquid arrives and a lower opening through which the liquid is discharged, the intermediate and lower openings being located respectively at the level of the pipe immediately upstream of the tank and at the level of the pipe immediately downstream of the tank. System according to claim 20, characterized in that the intermediate and lower openings are connected by a section of pipe making an angle (ϑ) equal to or greater than 45 ° relative to the horizontal. System according to one of the preceding claims, characterized in that the lower part (1b) of the reservoir has an opening (1c) for the outlet of the liquid and connected to the pipe (2), and a safety device cooperating with said opening to prevent complete emptying of the tank and air leakage into the pipeline from the tank. System according to claim 22, characterized in that the safety device comprises a float (46), a flexible membrane (47) suspended from the float by flexible lines (48) and a plate (49) provided with a central grid ( 50) covering the section of the pipe (42) opening into the opening (1c) of the tank, the membrane being fixed in its center to the grid and being able to completely cover the grid. System according to claim 23, characterized in that the float (46) is in the form of a horizontal plate provided with several lugs (51) on the lower surface which can come into contact with the plate (49) provided with the grid ( 50).

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