Pneumatic purge valve, object flotation control system and corresponding control method

Abstract

Pneumatic purge valve for a balloon (3) at least partially filled with gas immersed in a liquid, comprising a body (10, 11, 12) arranged on either side of an opening made in a wall of the balloon (3), the body (10, 11, 12) being provided with at least one opening (20) so as to put the inside and the outside of the balloon (3) into communication, the purge valve further comprising a piston (14) provided with at least one return spring (16, 17), the purge valve (5) comprising a source of compressed gas connected to the purge valve (5) via a solenoid valve controlled by a control device, the piston (14) passing into the open position when the force exerted by the compressed gas on the piston (14) is greater than the sum of the return forces of the springs (16, 17) and the pressure exerted by the liquid on the piston (14), releasing gas. Figure for abstract: Fig 4

Description

Title of the invention: Pneumatic purge valve, system for controlling the flotation of an object and corresponding control method Technical field

[0001] The technical field of the invention is flotation systems in liquid media, and more particularly the control of the flotation of objects equipped with such systems. Prior techniques

[0002] Controlling the buoyancy of an object lies in controlling the balance of forces between the weight of the object, the Archimedean force acting on the object and resulting from the reaction of the liquid medium and the driving force applied to the object.

[0003] Depending on the nature of the object, these forces can have various origins. By object, we mean a diver as well as a heavy load or a wreck.

[0004] The driving force applied to the object may result from the operation of propulsion means, such as thrusters, or from the action of a system external to the object, such as traction by a cable or rope.

[0005] The weight of the object depends on the mass of the object, which can be modified by means of a ballast. A ballast is a rigid container coupled to at least one pump, which can be filled with liquid or emptied of the contained liquid. Depending on the filling of the ballast, the mass of the object varies without changing the volume of liquid displaced by the object.

[0006] Archimedes' force depends on the mass of the volume of liquid displaced. Thus, inflating or deflating a balloon allows the volume of liquid displaced to be modified and, consequently, the intensity of Archimedes' thrust. The volume of an inflated balloon also depends on the depth at which the object is located, due to the pressure applied to the balloon by the liquid in which it is immersed in accordance with Pascal's principle. Thus, for a volume at a given depth, the volume will increase when the depth decreases while the volume will decrease when the depth increases. It thus appears that Archimedes' force depends indirectly on the depth of the object.

[0007] From this balance of forces, it appears that the buoyancy of an object, that is to say its capacity to float or to sink in a liquid depends on the driving force, the weight, the Archimedes' thrust and Pascal's principle. From the above statement, we understand that only submarines can modify their mass and therefore their weight by the use of ballast, only self-propelled or towed vessels can modify their driving force and only objects linked to a balloon can modify their thrust. Archimedes' thrust. We are here in this last category of objects, the balloon being able to be for example a lifting balloon or a diver's stabilizing vest. A diver's stabilizing vest comprises at least one inflatable envelope placed in or attached to a harness donned by the diver and allowing him to modify his Archimedes' thrust by admitting or purging gas coming from his air reserve (diving bottle).

[0008] When the object sinks into a liquid, it undergoes an increase in pressure which reduces the volume of the balloon. The volume of displaced liquid is reduced, the Archimedes' thrust decreases as a result, and the speed of descent increases.

[0009] The opposite effect appears during ascent, the object undergoing a reduction in pressure, which allows the volume of the balloon to increase. The only limit to this increase in volume is the mechanical resistance of the balloon. The volume of displaced liquid increases, the Archimedes' thrust increases as a result, and the ascent speed increases.

[0010] However, the increase or decrease in the resulting force of the force balance involving weight and Archimedes' thrust leads to a constant acceleration, which, in a liquid medium, can lead to an accident. It is then necessary, in addition to controlling the direction of the force balance depending on the desired rise or descent, to control the cancellation of the force balance in order to maintain a constant speed, more easily understood in a liquid medium.

[0011] Currently, it is necessary to manually change the balloon volume by reducing or increasing it according to the estimated speed (for example, according to the rising speed of gas bubbles) or according to a depth gauge. Estimating the reduction or increase of the balloon volume is complex depending on the object concerned (diver, load, wreck), requires special training as well as significant attention. In certain circumstances, the operator may not make the right decision or may no longer be able to make decisions, which may have fatal consequences.

[0012] There is a need for a buoyancy control system for controlling the reduction or increase in the volume of a balloon as a function of depth so as to maintain a constant descent or ascent speed. Disclosure of the invention

[0013] The subject of the invention is a pneumatic purge valve for a balloon at least partially filled with gas immersed in a liquid, comprising a body arranged on either side of a wall of the balloon around an opening made in said wall, the body being provided with at least one opening so as to put the inside and the outside of the balloon in communication, the purge valve further comprising a piston provided with at least one return spring bearing on the body and exerting a return force in order to return said piston to the closed position, the purge valve comprising a source of compressed gas and a solenoid valve connected on the one hand to the source of compressed gas and on the other hand to the purge valve and controlled by a control device, the piston being at rest in the closed position under the combined effect of the return forces of the springs and the pressure exerted by the liquid in which the balloon is immersed, so that no gas passes from the inside of the balloon to the outside of the balloon through the body, the piston passing into the open position, when the force exerted by the compressed gas on the piston is greater than the sum of the return forces of the springs and the pressure exerted by the liquid on the piston, so that gas passes from the inside of the balloon to the outside of the balloon

[0014] The body may comprise a lower body disposed inside the balloon around an opening in the balloon and an intermediate body disposed outside the balloon around said opening and an upper body provided with at least one opening cooperating with the lower body and the intermediate body so as to connect the inside and the outside of the balloon. The piston may be provided with a head and an axis, the head of the piston being disposed between the upper body and the intermediate body and is provided with a piston return spring bearing on the upper body and exerting a head return force in order to return said piston to the closed position, the axis being disposed between the intermediate body and the lower body and is provided with an axis return spring bearing on the intermediate body and exerting a return force on the axis of the piston in order to also return said piston to the closed position.

[0015] The pneumatic purge valve may comprise means for fixing the lower body and the intermediate body, in particular in the form of threaded hole / screw assemblies, the intermediate body comprising on its external surface a thread designed so as to be able to cooperate with a thread provided on the internal surface of the upper body.

[0016] The invention also relates to a system for controlling the buoyancy of an object, a purge valve as described above, the control system comprises a depth gauge connected to the control device and a control means allowing an operator to interact with the control device, the control device comprising an inlet solenoid valve arranged between a source of inlet compressed gas and the inlet means, a purge solenoid valve arranged between a source of purge compressed gas and the purge valve, the control device comprising at least one calculation means configured so as to control the solenoid valves as a function of a target depth and the depth of the object.

[0017] The object may be a diver or equipment, the balloon being able to be respectively a diver's stabilizing vest or an equipment lifting balloon or an equipment lifting parachute.

[0018] The operator may be a diver equipped with a diver's stabilizing vest, a diver supervising equipment equipped with a lifting balloon or parachute or a person on board a ship, in charge of a diver equipped with a diver's stabilizing vest or equipment equipped with a lifting balloon or parachute.

[0019] The inlet solenoid valve and the purge solenoid valve can be connected to the same source of compressed gas.

[0020] The compressed gas source may be at least one of a compressed gas cylinder and a gas compressor on board a watercraft.

[0021] The control means can be connected to the control device by a wired connection or by a wireless connection, in particular a connection by acoustic waves.

[0022] The control device and the solenoid valves may be included in a sealed and pressure-resistant housing.

[0023] Another object of the invention is a method for controlling the buoyancy of an object provided with a control system as described above, comprising the following steps: a. an operator initializes a target depth, a wait time, and at least one of a target depth, a stop depth, a descent rate, an ascent rate, a first depth deviation, a second depth deviation, a descent rate threshold, an ascent rate threshold, and the mass of the object, then b. during immersion, the following steps are carried out: i. the depth of the object is determined at a date equal to a present instant, ii. the speed and acceleration of the object at the present time are determined as a function of at least one depth determined until then, iii. the depth that the object will have at a future instant is determined as a function of the determined speed and acceleration, the future instant being equal to the present instant plus the waiting time, iv. it is then determined whether a descent or an ascent is requested, 1. if a descent is requested, the process continues with a set of sub-steps designed to control the inflation or purging of the balloon so that the descent speed is at most equal to the initialized descent speed and that the depth reached is less than or equal to the target depth, the set of sub-steps being carried out at the present time, 2. if an ascent is requested, the method continues with a set of sub-steps designed to control the inflation or purging of the balloon so that the ascent speed is at most equal to the initialized ascent speed and the depth reached is less than or equal to the stop depth, the set of sub-steps being carried out at the present time, v. a waiting time is then waited and the process then resumes with the determination of the depth.

[0024] The balloon can be inflated by admitting compressed gas for a predetermined inflation time, less than an actuation time.

[0025] The balloon can be purged by purging the gas contained in the balloon during the actuation period.

[0026] The inflation time and the actuation time can be modulated by a factor resulting from a proportional integral control derived as a function of the depth and taking into account a residual volume of gas in the balloon at the surface.

[0027] A correction to the Archimedean force can be determined as a function of the variation in volume of the balloon due to the variation in water pressure when the object changes depth, the correction being a function of the pressure measurements, the waiting time, and a residual volume of gas in the balloon at the surface, half of the correction to the Archimedean force being summed to the acceleration when determining the depth at the future time. Brief description of the drawings

[0028] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings in which:

[0029] - Figure [Fig.l] illustrates the main elements of a control system of the buoyancy of an object according to a first embodiment,

[0030] - Figure [Fig.2] illustrates the main elements of a control system of the buoyancy of an object according to a second embodiment,

[0031] - Figure [Fig.3] illustrates the main elements of a control device included in a system for controlling the buoyancy of an object according to the invention,

[0032] - Figure [Fig.4] illustrates the main elements of an actuated purge valve pneumatically included in a system for controlling the buoyancy of an object according to the invention,

[0033] - Figure [Fig.5] illustrates the main steps of a method of controlling the buoyancy of an object, and

[0034] - Figure [Fig.6] illustrates the main sub-steps of the control method of the buoyancy of an object during a descent of the object, and

[0035] - Figure [Fig.7] illustrates the main sub-steps of the control method of the buoyancy of an object during a rise of the object, Detailed description

[0036] The system for controlling the buoyancy of an object according to the invention comprises a control device, a control means and at least one balloon connected to the object whose buoyancy is to be controlled.

[0037] The at least one balloon is provided with at least one admission means and at least one purge valve, controlled by the control device.

[0038] The at least one intake means is fluidically connected to a compressed gas source and is configured to introduce gas from the gas source into the balloon to inflate it.

[0039] The at least one purge valve is also fluidly connected to a source of compressed gas and is configured to purge gas from the balloon to deflate it.

[0040] By compressed gas source is meant a compressed gas cylinder or a gas compressor on board a boat. In a particular embodiment, the gas source connected to the intake means and the gas source connected to the purge valve are one and the same gas source. When the object is a diver, the gas source connected to the intake means and to the purge valve is possibly common with the gas source allowing said diver to breathe.

[0041] Figure [Fig.l] illustrates a control system 1 for the buoyancy of an object 2 according to a first embodiment, in which the balloon 3 is a lifting balloon.

[0042] The control system 1 comprises a balloon 3 connected to the object 2 by a harness, the balloon 3 being provided with an intake means 4 and a purge valve 5. The control system 1 comprises a control device 6 for controlling the intake means 4 and the purge valve 5 and a control means 7 allowing an operator to interact with the control device 6. The connection between the control device 6 and the control means 7 is wired or wireless, in particular acoustic.

[0043] Figure [Fig.2] illustrates a control system 1 for the buoyancy of an object 2 according to a second embodiment, in which the balloon 3 is a stabilizing vest for a diver. It should be noted that in this figure, the strap securing the object (here, a diving bottle) to the balloon 3 (the diver's stabilizing vest) is not illustrated.

[0044] In the two embodiments illustrated by figures [Fig.l] and [Fig.2], the at least one admission means and the at least one purge valve are designed and dimensioned according to the volume of the balloon.

[0045] The control device 6 comprises at least one calculation means connected to at least one memory and to at least one communication means. The at least one communication means is unidirectional or bidirectional, and makes it possible to configure the control device 6 when the control system 1 is out of the liquid, to interact with the control means 7 and to transmit instructions to solenoid valves pneumatically actuating the at least one purge valve and supplying the at least one intake means.

[0046] It should be noted that the use of solenoid valves makes it possible to electronically control the admission and purging of gas in the balloon without direct intervention by a diver. This is to be compared with the prior art, in which the admission of gas is carried out manually by a diver through the actuation of an admission means on a diver's stabilizing vest or a regulator for inflating balloons and lifting parachutes.

[0047] Similarly, purging is carried out by means of a purge valve on a stabilizing vest, possibly combined with the admission means in a so-called "direct system" and by opening a valve in a lifting balloon. Here again, these actions are carried out manually by a diver.

[0048] The at least one computing means is designed to carry out the steps of the control method described below.

[0049] Figure [Fig.3] illustrates the main elements of a control device 6.

[0050] The control device 6 comprises a calculation means 6a such as a processor, coupled to a memory 6b and to at least one communication means 6c.

[0051] The control device 6 is connected directly or indirectly to a depth gauge. It will not be outside the scope of the invention if the depth gauge is integrated into the control device 6.

[0052] The control device 6 also comprises a solenoid valve 4b of the intake means and a solenoid valve 5b of the purge valve, each connected upstream to a source of compressed gas via a flexible hose 2a of the compressed gas source. In another embodiment, each solenoid valve can be connected to its own source of compressed gas. However, the pooling of gas sources compressed helps prevent a gas deficiency for purge or intake that could disable the buoyancy control system.

[0053] The solenoid valve 4b of the intake means is connected to the intake means 4 by via the hose 4a of the intake means. The purge valve solenoid valve 5b is connected to the purge valve 5 via the purge valve hose 5a.

[0054] The at least one communication means 6c is connected to the control means 7 via the control cable 7a, possibly via a sealed connector 7b.

[0055] According to the embodiments, the at least one communication means 6c comprises a data connection with the outside, either in the form of a wireless connection, in the form of a connector 7c for a data cable, or in the form of a receptacle for physical memory, such as an SD card or one of its variants (microSD, in particular).

[0056] Several means of communication can be provided, each designed to manage a limited number of connections.

[0057] The assembly is powered by an energy source 8, in particular a rechargeable or exchangeable battery or a generator.

[0058] The control device 6, the solenoid valve 4b of the intake means and the solenoid valve 5b of the purge valve are included in a box 9 designed to be watertight and pressure-resistant.

[0059] A sealed wall-pass connector 2c, 4c, 5c is provided for the connection of each hose 2a, 4a, 5a. The wall-pass connectors 2c, 4c, 5c and the sealed connectors 7b, 7c are designed to protect the physical integrity of the box 9 with respect to pressure changes during the descent or ascent of the object 2.

[0060] The box 9 is also designed so that the pressure sensor of the depth gauge is at least partially in contact with the exterior of the box 9 so as to measure the pressure exerted on the box and on the object 2. This contact with the exterior is designed to protect the physical integrity of the box 9 with respect to changes in pressure during the descent or ascent of the object 2.

[0061] In certain embodiments, the box 9 is provided with means for discharging excess pressure, in particular by means of a non-return valve.

[0062] When the battery 8 is rechargeable, a specific waterproof connector is provided for connecting a battery charging cable. As for the other waterproof connectors 7b, 7c, this connector is designed to protect the physical integrity of the box 9 with respect to changes in pressure during the descent or ascent of the object 2.

[0063] The pneumatically actuated purge valve 5 is illustrated in figure [Fig.4].

[0064] The purge valve 5 comprises a lower body 10, an intermediate body 11, an upper body 12 and a piston 14 provided with a head 14a and an axis 14b, as well as a lining 15 cooperating with the piston in order to ensure the sealing of the purge valve 5 when the piston is in the closed position.

[0065] The lower body 10 is arranged on the wall of the balloon inside the latter, while the intermediate body 11 is arranged on the wall of the balloon, outside the latter. Once fixed together by means of fixing means 18, the lower body 10 and the intermediate body 11 make it possible to secure the purge valve to the balloon around an opening made in the wall 3a thereof.

[0066] The upper body 12 is fixed to the intermediate body 11 in a removable manner, thus allowing access to the piston. At least one opening 20 is provided in the upper part of the upper body 12.

[0067] A shaft return spring 16 and a piston return spring 17 are provided and cooperate to hold the piston in the closed position. The shaft return spring 16 bears on the intermediate body 11 and exerts a force on the shaft 14b of the piston 14. The piston return spring 17 bears on the upper body 12 and exerts a force on the head 14a of the piston 14.

[0068] Means 18 for fixing the lower body 10 and the intermediate body 11 are also provided, in particular in the form of threaded hole / screw assemblies.

[0069] Finally, the intermediate body 11 comprises on its external surface a thread 19a designed so as to be able to cooperate with a thread 19b provided on the internal surface of the upper body 12.

[0070] A halyard 21 arranged through one of the openings 20 of the upper body 12 is secured to the piston 14 at one of its ends. The other end is left free. The halyard 21 allows manual actuation of the purge valve 5. In one embodiment, this other end is provided with a handle facilitating the gripping and actuation of the halyard 21.

[0071] In the lower part, the purge valve 5 is connected to the purge valve hose 5a connected to the compressed gas source via a solenoid valve 5b of the control device 6.

[0072] In operation, the forces generated on the piston 14 by the axis return spring 16, by the piston return spring 17 as well as the pressure exerted by the liquid in which the balloon is immersed keep the piston in the closed position.

[0073] When a compressed gas is admitted into the purge valve 5, the piston 14 experiences a force opposing the sum of the forces of the axis return spring 16 and the piston return spring 17 as well as the pressure exerted by the liquid. The piston 14 moves into the open position when the force resulting from the admission of compressed gas exceeds the sum of the forces of the piston return spring 17 and the axis return spring 16 as well as the pressure exerted by the liquid.

[0074] This purge valve 5 allows:

[0075] • to release a large volume of gas very quickly, particularly in the area close to the surface to ensure depth is maintained without the object accelerating towards the surface. It is sized according to the flow of compressed gas to be released, which is itself proportional to the volume of the balloon.

[0076] • to operate while consuming a minimum of energy. The choice was made to use a pneumatic purge valve connected directly to the compressed gas source (e.g. the regulator of the diver's compressed air cylinder). It is therefore the pressure of the cylinder (compressed gas source) which will mechanically actuate the purge valve. It is the energy of the compressor which is indirectly restored and used.

[0077] • to guarantee the total opening of the purge valve at great depth. The piston being positioned at the end and in abutment of an axis, it is systematically detached from the intermediate body as soon as compressed gas is admitted at sufficient pressure. It should be noted that the modulation of the purged gas thus results solely from the duration of opening of the valve.

[0078] Concerning the actuation of the purge valve, the following example is given. The pressure of a diving cylinder is between 150 bar and 450 bar while the pressure exerted by the water on a submerged object increases by 1 bar every 10 m. It can be deduced that, given the ratio between the surface area of ​​the piston axis and the piston head, actuation of the purge valve is possible up to at least 1500 m with a diving cylinder at 150 bar, i.e. a depth well above human resistance to pressure and cold and the autonomy conferred by such a diving cylinder. It is understood that a pressure regulator is arranged between the source of compressed gas and the solenoid valves so as to reduce the pressure at the inlet of the solenoid valves to a level admissible for them.

[0079] The method of controlling the buoyancy of an object makes it possible to control the descent rate, to control the ascent rate or to control the stabilization of the object at the current depth.

[0080] However, since entering a simple descent or ascent speed can be dangerous, particularly in the case where the object is a diver, these speeds are accompanied by stabilization at a predetermined depth. During descent, a depth limitation protects the diver against depth narcosis, making him unable to stop the descent. This stabilization can be accompanied by a maximum depth limit not to be exceeded, protecting the object against an input error in the predetermined depth. The maximum depth limit can be linked to the mission in the case where the object is equipment, or be linked to the technical level of the diver (as defined in a national system, such as the FFESSM “French Federation of Underwater Studies and Sports” or in the Padi association “Professional Association of Diving Instructors”) or be linked to the gas mixture used for the diver's breathing (air, “nitrox”, “trimix”, etc.).

[0081] The calculation means 6a included in the buoyancy control system is configured to execute the steps of a buoyancy control method.

[0082] The control means 7 further comprises at least one button among an ascent button, a descent button, a stabilization button and a pause button. In a particular embodiment, the control means 7 comprises at least the ascent button.

[0083] The control process can be paused or resumed by pressing the same button on the control means 7.

[0084] The method of controlling the buoyancy of an object is illustrated by the figures [Fig.5], [Fig.6] and [Fig.7],

[0085] Referring to figure [Fig.5], the method for controlling the buoyancy of an object comprises a first parameterization step 31, during which a target depth PcMe is entered by an operator. The operator may be the diver, a diver supervising equipment or a person on board a ship, in charge of a diver or equipment. The parameters of depth of stops P of descent speed (for example 18m / min), of ascent speed (for example 10m / min), a first depth difference, a second depth difference, a speed difference, the mass m of the object are also entered. A calculation time interval dt is also defined, in particular 3s, as well as a number of occurrences of a calculation loop making it possible to set the prediction horizon of the depth, speed and acceleration values ​​of the object. The number of occurrences of the calculation loop is at least equal to 1.We initialize a counter of occurrences of the calculation loop to 1.

[0086] The control method continues with a second step 32, during which the control method is initialized at the time of immersion. The depth p(t) of the object is determined, in particular by means of the depth gauge. It is recalled that the depth (in m) (denoted p(t)) is obtained from a measurement of the pressure (in bar) (denoted Pres(t)) by applying the following formula:

[0087] [Math.l] p(t) = (Presit)-l)*10

[0088] We then wait for a waiting time dt, in particular three seconds.

[0089] At the end of this waiting period, the control method continues with a second step 33 during which the depth of the object is determined. During the first occurrence of step 33, the current time is t+dt and the determined depth is + dt).

[0090] During a fourth step 34, still at the instant we determine the speed dt + di) the acceleration dt + dt) of the object by applying the following equations:

[0091] [Math.2] dt + di) = (p(t + dt) -p(t)) / dt

[0092] [Math.3] dt + di) = dv(t + dt) -v(t)) / dt

[0093] It should be noted that the acceleration is determined based on three depth measurement values. Thus, for a determination of the acceleration at time t+dt, depth measurements at t-dt, t and t + dt are necessary. It is evident that this recursive calculation requires at least one measurement that is not available during the first iteration. At t=dt, the depth measurement dt-dt) is not available. At t=2dt, all depth measurements ^t + 2dt), p(t + 3di) and + Adi) are available.

[0094] In one embodiment, during the first step 32 of the method, the depth at t - dt is initialized to the same value as the first depth measurement at di) - In other words, we set:

[0095] [Math.4] p(t-dt) = p$

[0096] The method continues with a fifth step 35 during which, still at time t + dt, the depth p(t+2dt) that the object will have after a new waiting time dt is determined, i.e. at time t + 2dt, by applying the following equation [Math 5]:

[0097] [Math.5] p(t + 2dt) = |*a(t + dt) *(2dt) 2 + y (t + dt ) *(2dt ) + p(t + di)

[0098] At the end of the fifth step 35, we are still at time t+dt and we then have the depth p(t + 2dt) that the object will have at time t + 2dt, the depth p(t + dt) at time t+dt, the speed + dt) at time t + dt and the acceleration dt + di) at time t + dt.

[0099] During a sixth step 36, it is determined whether the loop comprising steps 33 to 35 has been carried out a predefined number of occurrences by determining whether the value of the occurrence counter of the calculation loop is equal to the predefined value of occurrences of the calculation loop. If this is not the case, the duration is waited for waiting time dt, the occurrence counter is incremented by one unit and the process resumes at the third step 33. If this is the case, the process continues with a seventh step 37.

[0100] The control method continues with a seventh step 37 during which it is determined whether a descent or an ascent is requested, in particular depending on the button pressed on the control means 7.

[0101] Depending on the result of the seventh step 37, the method continues with an eighth step 38 of descent or with a ninth step 39 of ascent.

[0102] At the end of one or other of steps 38 or 39, a new time increment dt is waited for, the occurrence counter of the calculation loop is reset to 1 and then the control method resumes at the third step 33.

[0103] The sub-steps included in the descent step 38 will now be described and are illustrated by the figure [Fig.6]. All of these sub-steps are described below by being carried out at time t+dt corresponding to the carrying out of step 38 after a single calculation loop (steps 33 to 35). For a carrying out at a later time, the equations will be incremented by an appropriate number of time increments dt and all of the sub-steps carried out directly at the corresponding time (for example, at t+3dt without having been calculated at each previous time instant, t+dt, t +2dt).

[0104] During a first sub-step 40, it is determined whether a descent has been requested. If this is not the case, the method is interrupted. If this is the case, the method continues with a second sub-step 41 during which the values ​​of the initialized parameters and the determined and predicted depth, speed and acceleration values ​​are recovered.

[0105] The control method then continues with a third sub-step 42, during which it is determined whether the depth p(t + 2dt) that the object will reach at time t + 2dt will be greater than the target depth Pàbie-

[0106] If this is not the case, the method continues with a fourth sub-step 43, during which it is determined that the object is rising while a descent is expected. A purge of the balloon is then ordered and the control method resumes at the first sub-step 40.

[0107] If it has been determined that the depth p(t + 2dt) that the object will reach at time t + 2dt is greater than the target depth P target, the method continues with a fifth sub-step 44, during which the difference between the depth p(J +2dt) that the object will reach at time t + 2dt and the target depth P target is determined.

[0108] If the difference between the depth p(t + 2dt) that the object will reach at time t+2dt and the target depth P target is greater than a first predetermined depth difference, in particular 20cm, the method continues with a sixth sub-step 45 during which determines that the object is too deep. The balloon is inflated to raise the object. Step 38 ends and the process then resumes at the third substep 33.

[0109] If the difference between the depth p(t + 2dt) that the object will reach at time t+2dt and the target depth Pcibie is greater than a second predetermined depth difference, in particular -20cm, the method continues with a seventh sub-step 46 of speed verification.

[0110] During the seventh sub-step 46, the difference between the speed v(J+dt) that the object will reach at time t + dt and the parameterized descent speed is determined. [YES] If the difference between the speed v(t + dt) that the object will reach at time t + dt and the parameterized descent speed vdescent is greater than a descent speed threshold, for example 20cm / s, the control method continues with an eighth sub-step 47 during which it is determined whether the acceleration a(t + dt) that the object will reach at time t + dt is positive. If this is the case, the method continues with a ninth sub-step 48 during which it is determined that the object is accelerating while the speed is too high. The inflation of the balloon is then commanded in order to brake the object. Step 38 ends and the method then resumes at the third sub-step 33.

[0112] If the acceleration a(t + dt) that the object will reach at time t + dt is not positive, we deduce that the object is slowing down while the speed is too high. The quantity of gas in the balloon is not modified. Step 38 ends and the method then resumes at the third sub-step 33.

[0113] If the difference between the speed v(t + dt) that the object will reach at time t + dt and the parameterized descent speed vdescent is less than the descent speed threshold, the control method continues with a tenth sub-step 49 during which it is determined whether the acceleration a(J + dt) that the object will reach at time t + dt is positive. If this is not the case, the method continues with an eleventh sub-step 50 during which it is determined that the object is slowing down while the speed is insufficient. The balloon is then purged in order to accelerate the object. Step 38 ends and the method then resumes at the third sub-step 33.

[0114] If the acceleration a{t + dt) that the object will reach at time t + dt is positive, we deduce that the object is accelerating while the speed is insufficient. The quantity of gas in the balloon is not modified. Step 38 ends and the method then resumes at the third sub-step 33.

[0115] If the difference between the speed v(t+df) that the object will reach at time t + dt and the parameterized descent speed vdescent is zero, the quantity of gas in the balloon is not modified. Step 38 ends and the method then resumes at the third sub-step 33.

[0116] If the difference between the depth p(t + 2dt) that the object will reach at time t + 2dt and the target depth P target is between the first depth difference and the second depth difference, the method continues with a sub-step 51, during which an ideal speed y 4. 2dt) is determined to stop at depth ^«e.by applying the following equation:

[0117] [Math.6]

[0118] The method then continues with a twelfth sub-step 52.

[0119] The control method continues with a twelfth sub-step 52 during which determines the difference between the speed v(t + dt) that the object will reach at time t + dt and the ideal descent speed v id(t + 2dt)-

[0120] If the difference between the speed v(J + dt) that the object will reach at time t + dt and the ideal descent speed y id(t+2di) is greater than the descent speed threshold, the control method continues with a thirteenth sub-step 53 during which it is determined whether the acceleration a{t + dt) that the object will reach at time t + dt is positive. If this is the case, the method continues with a fourteenth sub-step 54 during which it is determined that the object is accelerating while the speed is too high. The inflation of the balloon is then commanded in order to brake the object. Step 38 ends and the method then resumes at the third sub-step 33.

[0121] If the acceleration a(t + dt) that the object will reach at time t + dt is not positive, we deduce that the object is slowing down while the speed is too high. The quantity of gas in the balloon is not modified. Step 38 ends and the method then resumes at the third sub-step 33.

[0122] If the difference between the speed v(t + df) that the object will reach at time t + dt and the ideal descent speed y idif + 2dt) is less than the descent speed threshold, the control method continues with a fifteenth sub-step 55 during which it is determined whether the acceleration a(t + dt) that the object will reach at time t + dt is positive. If this is not the case, the method continues with a sixteenth sub-step 56 during which it is determined that the object is slowing down while the speed is insufficient. The balloon is then purged in order to accelerate the object. Step 38 ends and the method then resumes at the third sub-step 33.

[0123] If the acceleration a{t + dt) that the object will reach at time t + dt is positive, we deduce that the object is accelerating while the speed is insufficient. The quantity of gas in the balloon is not modified. Step 38 ends and the method then resumes at the third sub-step 33.

[0124] If the difference between the speed v(t + dt) that the object will reach at time t+dt and the ideal descent speed y jd(t + 2dt) is zero, the quantity of gas in the balloon is not modified. Step 38 ends and the process then resumes at the third sub-step 33.

[0125] The sub-steps included in the step 39 of ascent will now be described and are illustrated by the figure [Fig.7].

[0126] As for the sub-steps included in the descent step 38, all the sub-steps of the ascent step 39 are described below as being carried out at time t + dt, corresponding to the carrying out of step 39 after a single calculation loop (steps 33 to 35). For a carrying out at a later time, the equations will be incremented by an appropriate number of time increments dt.

[0127] During a first sub-step 60, it is determined whether an ascent has been requested. If this is not the case, the method is interrupted. If this is the case, the method continues with a second sub-step 61 during which the values ​​of the initialized parameters and the determined and predicted depth, speed and acceleration values ​​are recovered.

[0128] The control method then continues with a third sub-step 62, during which it is determined whether the depth p(J + 2dt) that the object will reach at time t+2dt is less than the depth p(t + dt) that the object will reach at time t + dt.

[0129] If this is not the case, the method continues with a fourth sub-step 63, during which it is determined that the object is descending while an ascent is expected. An inflation of the balloon is then commanded and the control method resumes at the first sub-step 60.

[0130] If it has been determined that the depth p(t+2dt) that the object will reach at time t + 2dt is less than the depth p(t+2dt) that the object will reach at time t + dt, the method continues with a fifth sub-step 44, during which the difference between the depth p(t+2dt) that the object will reach at time t + 2dt and the landing depth PpaHer is determined.

[0131] If the difference between the depth p(t + 2dt) that the object will reach at time t + 2dt and the landing depth Ppauer is greater than the first predetermined depth difference, the method continues with a sixth sub-step 65 during which it is determined that the object has risen too high. The balloon is purged in order to brake the object. Step 39 ends and the method then resumes at the third sub-step 33.

[0132] If the difference between the depth p(t + 2dt) that the object will reach at time t + 2dt and the landing depth PpaUer is greater than the second predetermined depth difference, the method continues with a seventh sub-step 66 of speed verification.

[0133] During the seventh sub-step 66, the difference between the speed F(t + dt) that the object will reach at time t + dt and the parameterized ascent speed Ascent is determined.

[0134] If the difference between the speed v(t + dt) that the object will reach at time t + dt and the parameterized ascent speed vascension is greater than an ascent speed threshold, for example 20cm / s, the control method continues with an eighth sub-step 67 during which it is determined whether the acceleration a(t + dt) that the object will reach at time t+dt is positive. If this is the case, the method continues with a ninth sub-step 68 during which it is determined that the object is accelerating while the speed is too high. The balloon is then purged in order to brake the object. Step 39 ends and the method then resumes at the third sub-step 33.

[0135] If the acceleration a{t + dt) that the object will reach at time t + dt is not positive, we deduce that the object is slowing down while the speed is too high. The quantity of gas in the balloon is not modified. Step 39 ends and the method then resumes at the third sub-step 33.

[0136] If the difference between the speed v{t + dt) that the object will reach at time t+dt and the parameterized ascent speed vascension is less than the ascent speed threshold, the control method continues with a tenth sub-step 69 during which it is determined whether the acceleration a(t + dt) that the object will reach at time t + dt is positive. If this is not the case, the method continues with an eleventh sub-step 70 during which it is determined that the object is slowing down while the speed is insufficient. The inflation of the balloon is then controlled in order to accelerate the object. Step 39 ends and the method then resumes at the third sub-step 33.

[0137] If the acceleration a(t + dt) that the object will reach at time t+dt is positive, we deduces that the object is accelerating while the speed is insufficient. The quantity of gas in the balloon is not modified. Step 39 ends and the process then resumes at the third sub-step 33.

[0138] If the difference between the speed v(t + dt) that the object will reach at time t + dt and the parameterized ascent speed vremmtted is zero, the quantity of gas in the balloon is not modified. Step 39 ends and the method then resumes at the third sub-step 33.

[0139] If the difference between the depth p(t + 2dt) that the object will reach at time t+2dt and the landing depth Ppaner is between the first depth difference and the second depth difference, the method continues with a sub-step 71, during which an ideal speed y îd\t + 2dt) is determined to stop at the landing depth Ppalier-V^ application of the following equation:

[0140] [Math.7] v_id(t+2dt) = (p(t + dt)-P palier )ldt

[0141] The method then continues with a twelfth sub-step 72.

[0142] The control method continues with a twelfth sub-step 72 during which determines the difference between the speed v(t + dt) that the object will reach at the instant t + dt and the ideal remount speed v_id( t + 2dt ) that the object will reach at time t + 2dt.

[0143] If the difference between the speed V(t + dt) that the object will reach at time t + dt and the ideal ascent speed v_id ( t + 2dt ) is greater than the ascent speed threshold, the control method continues with a thirteenth sub-step 73 during which it is determined whether the acceleration a(t + dt) that the object will reach at time t + dt is positive. If this is the case, the method continues with a fourteenth sub-step 74 during which it is determined that the object is accelerating while the speed is too high. The balloon is then purged in order to brake the object. Step 39 ends and the method then resumes at the third sub-step 33.

[0144] If the acceleration a(t + dt) that the object will reach at time t+dt is not positive, we deduces that the object slows down while the speed is too high. The quantity of gas in the balloon is not modified. Step 39 ends and the process then resumes at the third sub-step 33.

[0145] If the difference between the speed v(t + dt) that the object will reach at time t + dt and the ideal ascent speed v_id ( t + 2dt ) is less than the ascent speed threshold, the control method continues with a fifteenth sub-step 75 during which it is determined whether the acceleration a (t + dt) that the object will reach at time t + dt is positive. If this is not the case, the method continues with a sixteenth sub-step 76 during which it is determined that the object is slowing down while the speed is insufficient. The inflation of the balloon is then controlled in order to accelerate the object. Step 39 ends and the method then resumes at the third sub-step 33.

[0146] If the acceleration a(t + dt) that the object will reach at time t+dt is positive, we deduces that the object is accelerating while the speed is insufficient. The quantity of gas in the balloon is not modified. Step 39 ends and the process then resumes at the third sub-step 33.

[0147] If the difference between the speed V(t + dt) that the object will reach at time t + dt and the ideal ascent speed v_id ( t + 2dt ) is zero, the quantity of gas in the balloon is not modified. Step 39 ends and the method then resumes at the third sub-step 33.

[0148] To inflate the balloon, the solenoid valve 4b of the intake means is supplied for a predetermined inflation time, less than an inflation time, generally 10 ms.

[0149] To purge the tank, the purge valve solenoid valve 5b connected to the purge valve 5 is powered for a purge duration, generally 500ms.

[0150] In a particular embodiment, the inflation duration and the purge duration are modified by a parameter which is a function of the depth of the object at the time of activation of the solenoid valve 4b of the intake means or of the solenoid valve 5b of the purge valve and of the residual volume of gas in the balloon at the surface. The parameter is notably from a PID corrector (acronym for “Proportional Integral Derivative”)•

[0151] The residual volume of gas in the balloon at the surface is then initialized during the first step 31.

[0152] If the control method is paused at a given time, the resumption of the control method occurs at another later given time. This resumption involves a resumption of the control method at the second step 32 with the performance of new acquisitions of the depth of the object. These new acquisitions make it possible to redetermine the speed and acceleration of the object after the resumption of the method. Depending on the evolution of the object between the pausing and the resumption of the control method, the target depth may differ.

[0153] In a particular embodiment, the control method comprises determining a correction of the Archimedes force (dfc^t + ldi) as a function of the variation in volume of the balloon due to the variation in water pressure.

[0154] It is obtained by applying the formula:

[0155] [Math.8] dfdt + dt,t + 2dt) = (yol(t + 2dt) - vol(t + dt^rho^g

[0156] With:

[0157] vol)t + 2dt): The estimated volume at time t + 2dt,

[0158] vol(t + dt): the estimated volume at time t + dt.

[0159] rho:1a density of water

[0160] g: the acceleration of gravity

[0161] To determine the correction of the Archimedean force dfdd + 2dt), we first determine the volume yol(t + 2dt) estimated at time t + 2dt and the volume yol(t + dt) estimated at time t+dt, by applying the following equations:

[0162] [Math.9] vol(t + 2dt) = (j^t + dt)*vol(t + dt)) I (p(t + 2dt))

[0163] [Math. 10] vol(t + dt) = (p(t)*vol(t)) l(p(t + dt)

[0164] With:

[0165] vol(t): The estimated volume at time t equal to the residual volume on the surface at the time of launching.

[0166] We then determine a new acceleration a corr(t + 2dt) as a function of the estimated acceleration q.2dt) and correction of the Archimedes force dfdt + 2dt)

[0167] Note that the correction of the Archimedean force dfdf + 2di) is estimated over two time intervals dt. Its contribution in the force balance must therefore be divided by twice the mass to be comparable in magnitude to the estimated acceleration dt + 2dt)-

[0168] [Math. 11] a_corr(t + dt) = dj + dt) + ' / 2(dfa(.t + 2dt)*ll m)

[0169] The new acceleration a corAt + 2di) is then used in the equation [Math 5] instead of the acceleration + dt) in order to determine the depth + 2dt) at the future time t + -dt.

[0170] The remainder of the control method corresponds to the first embodiment described above.

[0171] The sub-steps of steps 38 and 39 have been described by being carried out at time t+dt by having the depth p(t + 2t) depth at time t + 2dt, the depth p{t + t) depth at time t + dt, the speed v(t + dt) that the object will reach at time t+dt, and the acceleration a(t + dt} that the object will reach at time t + dt.

[0172] In a particular embodiment, steps 38 and 39 are performed at time t+3dt while the depth p(t + 4t) at time t + 4dt, the depth p(t + ) at time t + 3dt, the speed V(t + 3dt) at time t + 3dt, and the acceleration a(t + 3dt) at time t + 3dt are available. These values ​​are determined after performing three calculation loops comprising steps 33 to 35. Steps 38 and 39 are then performed as a function of these values ​​at t+3d instead of the corresponding values ​​determined at t+dt.

[0173] In the case of an implementation at time t+dt, it is understood that steps 38 or 39 are carried out at t+dt, t+2dt, t+3dt, t+4dt,....

[0174] In the case of an implementation at time t+3dt, it is understood that steps 38 or 39 are carried out at t+3dt, t+6dt, t+9dt, t+12dt,....

[0175] The method for controlling the flotation of an object presented above can be applied to a diver's stabilizing vest as well as to one or more lifting or lifting balloons. Companies carrying out underwater work have divers trained in lifting and who know how to sling the balloons as close as possible to the center of gravity of the loads to be lifted.

[0176] Their job is first to develop a lifting strategy according to the result to be achieved. Generally, the operator's strategy when refloating a wreck is to ensure a constant attitude during the ascent to the surface. To achieve this, the same ascent speed and ceiling depth instruction is given to several balloons. Each balloon then complies with the instruction regardless of the weight and tension exerted on the sling that connects it to the wreck.

[0177] Flotation control therefore involves upstream programming of the lifting strategy and specific parameterization of the control system. the buoyancy of each balloon, each buoyancy control system being independent of the others. It is thus possible to organize a concerted and symbiotic work of a swarm of independent balloons. By independent balloons, we mean balloons not connected to each other by at least one cable and whose buoyancy is determined independently of that of the other balloons.

[0178] The flotation control system and the corresponding control method allow:

[0179] - to take off a load (in particular a wreck) encrusted with mud by over-inflating the balloons to compensate for the phenomenon of sand suction and then quickly and automatically deflate the excess gas to slow the rise,

[0180] - to slowly raise the load while maintaining a constant attitude,

[0181] - to adapt to the surface current which pushes the most exposed part of the load upwards, partially deflating the corresponding balloon and thus maintaining a constant attitude.

[0182] A predetermined attitude is thus given to the load and it is maintained during the ascent because the control system adapts:

[0183] • to the uneven distribution of the weight of the load, and

[0184] • to a fixing of the balloons more or less close to the center of gravity of the load.

[0185] Maintaining the attitude is possible because it is possible to inflate each balloon differently.

Claims

1.

2. Claims Pneumatic purge valve for a balloon (3) at least partially filled with gas immersed in a liquid, comprising a body (10, 11, 12) arranged on either side of a wall of the balloon (3) around an opening made in said wall, the body (10, 11, 12) being provided with at least one opening (20) so as to put the inside and the outside of the balloon (3) into communication, the purge valve further comprising a piston (14) provided with at least one return spring (16, 17) bearing on the body (10, 11, 12) and exerting a return force in order to return said piston to the closed position, the purge valve (5) comprising a source of compressed gas and a solenoid valve (5b) connected on the one hand to the source of compressed gas and on the other hand to the purge valve (5) and controlled by a control device (6), the piston (14) being at rest in the closed position under the combined effect spring return forces (16,17) and the pressure exerted by the liquid in which the balloon (3) is immersed, so that no gas passes from the inside of the balloon (3) to the outside of the balloon (3) through the body (10,11,12), the piston (14) passing into the open position, when the force exerted by the compressed gas on the piston (14) is greater than the sum of the return forces of the springs (16,17) and the pressure exerted by the liquid on the piston (14), so that gas passes from the inside of the balloon (3) to the outside of the balloon (3)., Pneumatic purge valve according to claim 1, wherein the body (10,11,12) comprises a lower body (10) arranged inside the balloon (3) around an opening in the balloon and an intermediate body (11) arranged outside the balloon (3) around said opening and an upper body (12) provided with at least one opening (20) cooperating with the lower body (10) and the intermediate body (11) so as to put the inside and the outside of the balloon (3) in communication, and wherein the piston (14) is provided with a head (14a) and an axis (14b), the head (14a) of the piston being arranged between the upper body (12) and the intermediate body (11) and is provided with a piston return spring (17) bearing on the upper body (12) and exerting a return force on the head (14a) in order to return said piston to the closed position, the axis (14b) being arranged between the intermediate body (11) and the lower body (10) and is provided with an axis return spring (16) bearing on the intermediate body (11) and exerting a return force on the axis (14b) of the piston in order to also return said piston to the closed position

3. Pneumatic purge valve according to claim 2, comprising means (18) for fixing the lower body (10) and the intermediate body (11), in particular in the form of threaded hole / screw assemblies, the intermediate body (11) comprising on its external surface a thread (19a) designed so as to be able to cooperate with a thread (19b) provided on the internal surface of the upper body (12).

4. A control system (1) for controlling the buoyancy of an object (2) comprising a purge valve (5) according to any one of claims 1 to 3, the control system (1) comprising a depth gauge connected to the control device (6) and control means (7) allowing an operator to interact with the control device (6), the control device (6) comprising an inlet solenoid valve (4a) arranged between an inlet compressed gas source and an inlet means (4), a purge solenoid valve (5a) arranged between a purge compressed gas source and the purge valve (5), the control device (6) comprising at least one calculation means configured to control the solenoid valves (4a, 5a) as a function of a target depth and the depth of the object.

5. A control system according to claim 4, wherein the object (2) is a diver or equipment, the balloon (3) being respectively a diver's buoyancy compensator or an equipment lifting balloon or an equipment lifting parachute.

6. A control system according to claim 4 or 5, wherein the operator is a diver equipped with a diver's buoyancy compensator, a diver supervising equipment equipped with a lifting balloon or parachute, or a person on board a vessel in charge of a diver equipped with a diver's buoyancy compensator or equipment equipped with a lifting balloon or parachute.

7. Control system according to any one of claims 4 to 6, wherein the inlet solenoid valve (4a) and the purge solenoid valve (5a) are connected to the same source of compressed gas.

8. A control system according to any one of claims 4 to 7, wherein the compressed gas source is at least one of a

9.

10.

11. compressed gas cylinder and gas compressor on board a boat. Control system according to any one of the claims 4 to 8, in which the control means (7) is connected to the control device (6) by a wired connection or by a wireless connection, in particular a connection by acoustic waves. Control system according to any one of claims 4 to 9, wherein the control device (6) and the solenoid valves (4a, 5a) are included in a sealed and pressure-resistant box (9). A method of controlling the buoyancy of an object provided with a control system according to any one of claims 4 to 10, comprising the following steps, executed by the computing means of the control system: a. an operator initializes (31) a target depth, a wait time, and at least one of a stop depth, a descent rate, an ascent rate, a first depth deviation, a second depth deviation, a descent rate threshold, an ascent rate threshold, and the mass of the object, then b. during immersion, the following steps are carried out: i. we determine (33) the depth of the object at a date equal to a current instant, ii. we determine (34) the speed and acceleration of the object at the current time as a function of at least one depth determined until then, iii. we determine (35) the depth that the object will have at a future instant as a function of the determined speed and acceleration, the future instant being equal to the current instant plus the waiting time, iv. we then determine (37) whether a descent or an ascent is requested, 1. if a descent is requested, the method continues (38) with a set of sub-steps designed to control the inflation or purging of the balloon so that the descent speed is at most equal at the initialized descent speed and that the depth reached is less than or equal to the target depth, the set of sub-steps being carried out at the instant current, 2. if an ascent is requested, the method continues (39) with a set of sub-steps designed to control the inflation or purging of the balloon so that the ascent speed is at most equal to the initialized ascent speed and the depth reached is less than or equal to the stop depth, the set of sub-steps being carried out at the current time, v. a waiting time is then waited for and the method then resumes with the determination (33) of the depth of the object at a date equal to the current time.

12. A method of controlling the buoyancy of an object according to claim 11, wherein the balloon is inflated by admitting compressed gas for a predetermined inflation time, less than an actuation time.

13. A method of controlling the buoyancy of an object according to claim 12, wherein the balloon is purged by purging the gas included in the balloon during the actuation period.

14. A method of controlling the buoyancy of an object according to claim 12 or 13, in which the inflation time and the actuation time are modulated by a factor resulting from a proportional integral servocontrol derived as a function of depth and taking into account a residual volume of gas in the balloon at the surface.

15. A method of controlling the buoyancy of an object according to any one of claims 11 to 14, wherein a correction to the Archimedean force is determined as a function of the variation in volume of the balloon due to the variation in water pressure when the object changes depth, the correction being a function measurements of pressure, waiting time, and residual volume of gas in the balloon at the surface, the correction for Archimedes' force divided by twice the mass of the object being added to the acceleration when determining the depth at the future time.

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