EP1580783A1 - Control device for the coordinated actuation of at least two switching devices, of which one is a vacuum switch - Google Patents

Abstract

The device has an auxiliary shaft (4) for permitting handling of a movable contact (5) of a vacuum switch (1) during movement of a main shaft (2). The shaft (4) crosses a wall (7A), of a case (7), that separates volume of isolating gaseous fluid (G 2) from another volume of blanket gas (G 1) at lower pressure. Difference between pressures of the fluid and the gas causes differential pressure force that is applied on the shaft (4). The differential pressure force is provided for assuring contact pressure force to hold the contact (5) against another contact (6).

Description

DESCRIPTION

The invention relates to a device for command for the coordinated actuation of at least two switching devices electrically connected in series to constitute a switching assembly of which one first switchgear in vacuum comprises a pair of separable contacts for switching between a closed position and a position opening. The control device comprises a main maneuvering shaft to operate a second switchgear immersed in an insulating fluid gaseous content in a certain volume at a pressure determined, and further comprises an auxiliary shaft able to be moved by coupling means for allow the operation of a mobile contact of the first switching device when moving from the main shaft, the moving contact being maintained in support against the other contact in the position of closing the first device by a force intended to produce a contact pressure greater than one determined value. It is indeed well known that certain contact pressure is usually necessary when a vacuum interrupter is closed, in order to prevent the contacts from separating under the effect electrodynamic repulsion forces in especially if a short circuit current runs the switch.

A device of this kind is known in particular from patent document WO9708723. The control device for operating a hybrid high voltage circuit breaker comprises a main operating shaft for operating a dielectric insulating gas switch such as SF ₆ . This hybrid circuit breaker is insulating in the air, since the gas switch breaking chamber is contained in an insulating casing which has fins on its outer surface. The main operating shaft is contained in a compartment delimited by a housing, which communicates with another compartment delimited by the insulating envelope of the gas switch to allow the main shaft to be connected to the moving contact of the switch. . This housing is sized to contain a vacuum switch whose fixed contact is connected to one of its walls. The housing is therefore a pole of the hybrid high voltage circuit breaker.

A connection terminal of this pole of hybrid circuit breaker is attached to the housing by being interposed between the two compartments, so that that the permanent current in the circuit breaker does not not pass through the vacuum switch which has for function to support the transient voltage of recovery during a power interruption. The mobile contact of the vacuum switch is electrically connected to the moving contact of the gas switch by a braid connection, and is actuated by an auxiliary shaft which includes spring means for producing a contact pressure sufficient when the vacuum interrupter is closed. This auxiliary shaft is perpendicular to the shaft main and is coupled by a lever shaped angle which pivots about an axis fixed to the housing, this which makes it possible to carry out a movement transfer substantially at 90 °.

The vacuum interrupter is subjected to the pressure of dielectric insulating gas that fills both compartments. Because almost zero pressure reigns in the sealed chamber of the vacuum interrupter also called vacuum bulb, this room must be designed to withstand the pressure forces of the gas outside that can be particularly intense especially on the cylindrical insulating wall as well as the metal bellows of the vacuum bulb. If the insulating gas pressure must be relatively high, generally greater than five bars in case of using a gaseous mixture with a proportion of nitrogen greater than 80% as known from the state of the technique, or even using pure nitrogen, it It is possible to use a vacuum bulb whose Waterproof chamber structure is designed for resist this pressure but this type of switch empty is still rare and particularly expensive. he is also possible to provide a reinforcement protector around the vacuum switch, as known of Japanese Patent Document JP 20003045300 which describes the realization of a resin molding around of a vacuum lamp intended to be immersed in a pure nitrogen medium under a pressure of several bars. This solution is still expensive to implement, and it remains difficult to avoid a pressure too much of insulating gas is applied in particular to the metal bellows of the bulb at the risk of deform or break it.

It is also known from the patent application in Europe EP 1 310 970 another device of this kind, which uses different coupling means for allow the maneuvering of the moving contact of the vacuum switch by an auxiliary shaft coupled to the main tree. In addition, both switching (not shown in this document patent) are electrically connected in series by the intermediary including a housing that encloses the coupling means and which communicates with the chamber of switch off the gas switch. As a result, the current permanent in the hybrid circuit breaker transits through the vacuum switch. The auxiliary shaft includes elastic means such as for example an arrangement springs or discs Belleville for produce sufficient contact pressure when the vacuum interrupter is closed. These elastic means are housed inside an abutment member having substantially the shape of a socket whose bottom is pierced to be traversed by the auxiliary shaft. This stop member is firmly inserted inside a flange which is connected to the housing and which participates in the serial electrical connection of the two switching devices. During an opening of the vacuum switch, the elastic means deform by being held between the bottom of the bush and a collar secured to a shaft of the tree auxiliary. The free distance between this necklace and a Shoulder of the socket determines the remaining stroke for the moving contact of the vacuum switch up the complete opening of the switch.

The vacuum switch is located in a adjacent compartment to the compartment delimited by the casing. The two adjacent compartments communicate the internal space of the stop member, even if the passage for the insulating gas through the arrangement of aforementioned springs is relatively narrow. So if the pressure of the insulating gas in the breaking chamber of the gas switch must be relatively high, the vacuum switch compartment will be inevitably subjected to identical pressure or almost equal. The problem of resistance to pressure for the waterproof chamber of the switch to empty can therefore also arise with such a device hybrid circuit breaker.

On the other hand, elastic means such as washers to produce the contact pressure in the vacuum switch does not allow to obtain a important race for the mobile contact of the switch. Typically, elastic washers allow a maximum run of the order of centimeter. But high-voltage hybrid circuit breakers will have to respond to ranges of higher and higher, which will require adopting vacuum switches with a contact gap of more and more important, typically greater than two centimeters. It seems in this case difficult to be able continue to use washers or springs to disks in the control device a vacuum switch, because the maximum spacing of contacts of this switch would then be limited by the characteristics of these elastic means of contact pressure regardless of characteristics intrinsic to the switch. We can remind subject that the maximum stroke intrinsically allowed for the moving contact of a vacuum interrupter depends generally elastic limits of the bellows metal sealing switch.

The adoption of conventional coil springs can to achieve the desired deflection for the mobile contact of the vacuum interrupter. But because of that the contact pressure is classically assured integrally by a mechanical spring, the dimensions and the moving mass of the pressure device of Spring contact must inevitably increase with the maximum intensity of short circuit allowed by the switch.

The object of the invention is to remedy these disadvantages. A first object of the invention is to allow to increase the insulating gas pressure in a gas switch of a switching assembly, and in particular a cut-off switch assembly hybrid, without this requiring increasing the protection of the vacuum switch against pressure gas that surrounds his tight chamber especially at level of the metal bellows seal. A second object of the invention is to propose a device for command for a switching assembly comprising a vacuum switch, which can be used to move from a mechanical elastic arrangement to produce the contact pressure in the switch or which allows at least such an elastic arrangement does not have to produce on its own most of the contact pressure required at the switch for transit a short circuit current. Finally, a goal annex is to allow the mobile contact to the vacuum switch to be maneuvered all over the race intrinsically allowed for the switch.

For this purpose, the subject of the invention is a control device as defined above, characterized in that the auxiliary shaft traverses with sealing a wall that separates the volume of fluid gaseous insulator from another volume of fluid to a lower pressure, the difference in pressures respective two fluids providing a certain force that is applied to the auxiliary shaft and which participates in the contact pressure force.

According to a first advantageous embodiment, part of the auxiliary shaft consists of a piston adapted to be moved within a bore formed by a piece which is sealingly mounted on an opening of the wall, sealing means at insulating gas being arranged between the piston and the bore. Preferably, the wall and the bore constitute a conductive assembly electrically connected to a pole of second switching device, the piston minus an electrically connected conductive part to the moving contact of the first switching device, and sliding contacts are disposed between the bore and the conductive portion of the piston. The wall can be constituted by a face of a housing which encloses least part of the volume of gaseous insulating fluid and in which the coupling means are arranged.

If the switching assembly is intended to be used as air-insulated switchgear, the crankcase is preferably open on one side which is tightly assembled with one end of a insulating jacket providing insulation in the air between the two poles of the second switching device. The casing is then placed directly in the air, and has a sealing role between the insulating gas of the second device and outside air.

If, on the other hand, the switching assembly is intended for use as a type of apparatus shielded in metal casing, the casing then has a role of mechanical support and no longer sealing since the metal casing of the apparatus is necessarily tight between the volume of fluid gaseous insulation and outdoor air.

According to a second embodiment, the wall is sealed to an electrically connected conductive plate at one pole of the second switching device and present a flexible zone in the center of which is provided a opening which is traversed with sealing by the shaft auxiliary. The flexible zone of the wall constitutes then a bellows seal that has a mechanical role producing a differential pressure force. Preferably, the auxiliary shaft includes a portion in the form of a guide piston adapted to be moved with electrical contact inside a bore electrically connected to the conductive plate.

In the two embodiments mentioned above, the coupling means may comprise means elastic compression mechanisms capable of exerting a resultant force on the auxiliary shaft to participate to the contact pressure force in addition to the force provided by the difference in pressures respective of the two insulating fluids

The invention, its characteristics and its advantages, are specified in the following description, with reference to the accompanying drawings which illustrate some embodiments as non-examples limiting.

Figure 1 schematically represents a control device according to the invention, applied to a set of disconnection and disconnection known per se and shown in the closed position of current flow.

Figure 2 schematically represents the control device of Figure 1 in position open current interruption by the set of switching.

Figure 3 schematically represents a control device according to the invention, applied to a hybrid switching assembly in which the switching apparatus in the vacuum is disposed of substantially perpendicular to the main axis of the switchgear in the gas.

Figure 4 schematically represents the control device of Figure 3 in the position opening of the switching assembly.

Figure 5 schematically represents a control device similar to that of Figure 3, in which is foreseen the possibility of a reclosing of the switchgear in the vacuum after the end of the circuit-breaker function provided by the switching in the gas.

Figure 6 schematically represents a control device similar to that of Figure 5, in an application for a switch set shielded.

Figure 7 schematically represents another control device according to the invention, in which the coupling means between the main shaft and the auxiliary shaft allow a similar result to that procured by the control device of the FIG. 3, and wherein a security evacuation is in the event of a leak in the means sealing to the gaseous insulating fluid.

Figures 7a and 7b represent very schematically the principle of maneuvering the contact mobile switchgear in the vacuum thanks to the rotating cam coupling means represented in Figure 7.

Figure 8 schematically represents the control device of Figure 3 to which are added elastic means to reinforce the contact pressure in the closed position of passage of the current in the switching assembly.

Figure 9 schematically represents a improvement of the actuation mechanism of the contact mobile of the switchgear in the vacuum such as shown in Figure 3, to increase the contact pressure in this device without increasing the maneuvering energy required for a control according to the invention.

Figure 9a is an enlargement of the mechanism of improved actuation which is represented on the FIG. 9 in the closed position of the set of switching.

Figure 9b schematically represents the actuating mechanism of Figure 9a in position opening of the switching assembly.

Figure 9c schematically represents another improved actuation mechanism of the movable contact of the switchgear in the vacuum, allowing a result similar to that provided by the actuating device of FIG. 9.

Figure 9d schematically represents another improved actuation mechanism of the movable contact of the switchgear in the vacuum.

Figure 10 schematically represents a alternative embodiment of the sealing means gaseous insulating fluid whose pressure is used for the operation of a control device according to the invention.

Figure 11 schematically represents a variant embodiment of the control device shown in Figure 10, which includes a space of atmospheric pressure safety running on the principle of security used in the device of control of Figure 7.

The control device according to the invention which is shown schematically in Figure 1 is applied to a switch assembly, and more precisely a set of cutoff and disconnection, as known in particular from the patent document WO 0074095 Al. It is described in this document a mechanism operating mechanism for the combined actuation of two switching devices electrically connected in series, with a first switching device in the empty and a second switching apparatus constituted a rotary knife disconnector placed in the air to provide a disconnect function after the power cut by the first device. The stem of operation of the moving contact of the vacuum interrupter can be actuated in translation by means of a cam pivotable to press against a solid shoulder from the stem to its end. The mechanism to ensure the contact pressure is not described in this document, but a conventional spring mechanism and / or by electromagnetic control can be used. The connecting rod of the swivel knife is articulated on a solidarity lever in rotation of the cam, likewise that the main maneuvering shaft is articulated on a other lever to drive the rotating cam.

Thus, a movement of the main tree of maneuver makes it possible to operate the two switching in a coordinated way, allowing respective mobile contacts of these devices to have movements that follow a temporal sequence determined. The profile of the cam allows here to separate quickly the contacts of the vacuum switch before that the rotation of the cam is sufficient to separate the pivoting knife of the fixed contact of the disconnector, this which corresponds to a normal sequence for such set of cutoff and disconnection.

The cut-out and disconnection assembly shown in FIG. 1 is similar in many respects to that described in patent WO 0074095 A1. The first modification according to the invention for this state of the art consists in providing a chamber filled with a gaseous insulating fluid G ₂ at a pressure P ₂ and in the volume V ₂ of which are housed the disconnecting apparatus 10 and a large part of the control device. This enclosure comprises a metal casing 7 which is electrically connected to the pivoting knife 15 of the disconnector 10 and which is open on the side of the disconnector 10 to be assembled in a sealed manner with an end of an insulating casing 18. The fact of having the disconnector disposed in a pressurized gaseous medium which has better dielectric insulation properties than the ambient air makes it possible to increase the dielectric strength of the disconnector in the open position, or to reduce the dimensions of the disconnector without reducing its dielectric strength.

The casing 7 constitutes one of the two poles of the disconnector, and the insulating casing 18 ensures the insulation in the air between the casing and the other pole which supports the fixed contact 16 of the disconnector. It is placed directly in the air, and has a sealing role between the insulating gas G ₂ and the air. The main operating shaft 2 comprises a translational portion which passes through the housing sealingly to be connected to a not shown control mechanism. As in the device of WO 0074095, coupling means 3 comprise a pivoting cam 14 integral with a lever on which is articulated a connecting rod 12 for actuating the pivoting knife 15. These means 3 make it possible to couple the respective movements of the main shaft 2 and the auxiliary shaft 4 which serves as operating rod of the movable contact 5 of the vacuum interrupter 1. This contact 5 is shown in the closed position of current flow, and bears against the contact fixed 6 of the vacuum switch to ensure the necessary contact pressure.

The auxiliary shaft 4 here comprises a piston 4A which crosspiece with sealing a wall 7A of the casing 7 and which is able to be moved inside a bore 8 formed by a piece that is tightly mounted on an opening of said wall 7A. Means 17 to the insulating gas G2, made by a O-ring, are arranged between the piston and the bore 8. The piston 4A has at least a part 4A2 electrically conductive which is assembled in electrical contact with the movable contact 5 of the vacuum switch. When moving the piston 4A, the piston portion 4A2 also remains in contact electric with bore 8 through contacts slippery like for example toric contacts to spring known per se.

The bore 8 opens out of the casing 7 on a volume V ₁ filled with a fluid G ₁ maintained at a pressure P ₁ less than the pressure P ₂ of the gaseous insulating fluid G ₂ in the housing. The fluid G ₁ may be an insulating gas, of the same nature or different from G ₂ , or a liquid or a dielectric gel, or a small volume of air or other gas at the pressure P ₁ without dielectric properties and provided adjacent a volume of solid or dielectric gel that surrounds the sealed chamber of the vacuum interrupter to provide dielectric isolation between the two poles of the switch. In FIG. 1, the fluid G ₁ represented is an insulating gas contained in a rigid insulating envelope 11 fixed sealingly against the casing 7 around its bore 8.

The difference between the pressure P ₂ of the gas G ₂ inside the casing 7 and the pressure P ₁ of the gas G ₁ inside the sealed envelope 11 applies to the piston 4A a differential pressure force Fp which is the product of the value P ₂ -P ₁ and the section of the piston in the bore 8. Depending on these parameters, the differential pressure force Fp can be provided to ensure the contact pressure force necessary to maintain the contacts 5 and 6 of the vacuum switch 1 rest against each other even if a short-circuit current flows through the switch. It should further be noted that the total differential pressure force exerted on the movable contact 5 of the vacuum interrupter 1 is actually the sum of the differential pressure force Fp defined above and the pressure force gas G ₁ which is exerted on the metal bellows 19 of sealing the vacuum interrupter, because this bellows makes a movable separation between the vacuum in the sealed chamber of the switch and the gas G ₁ around this room. In the following, the contact pressure force F _c is defined as the force to be exerted on the moving contact 5 of the vacuum interrupter in addition to the gas pressure force G ₁ exerted on the bellows d sealing the switch, in order to keep the contacts of the switch pressed against each other under specified current conditions.

In FIG. 2, the control device of the FIG. 1 is diagrammatically represented in position open current interruption by the set of switching. The part of the knife disconnector swivel is not shown, but it will be understood from by the position of the connecting rod 12 of operation of the knife pivoting of the disconnector that this knife is open. The movement of the main shaft 2 down the figure, driven by a control device not shown, causes rotation of the pivoting cam 14 whose profile is intended to support against the shoulder 4B of the auxiliary shaft 4 from the beginning of the rotation. The pressing force of the cam 14 against the shoulder 4B is provided sufficient to exceed the differential pressure force Fp that remains substantially constant over the entire stroke of the piston 4A. At the end of the piston stroke, as shown on the figure, contacts 5 and 6 of the vacuum interrupter are separated with a spacing planned not to exceed the elastic limits of the metal bellows 19 of this switch.

In FIG. 3, a control device according to the invention is shown schematically in a application for a switching set called hybrid breaker or circuit breaker hybrid, which associates the switchgear in the empty to a switchgear in a gas. In what follows, these two devices of switching are called respectively switch to empty and gas switch. The gas switch 10, not shown to the left of the figure, possesses typically a crew of mobile contacts including a moving arc contact adapted to be operated in translation by the main shaft 2 of maneuvering the hybrid circuit breaker. This main tree is connected classic way by an insulating rod to a mechanism not shown to the right of the figure. The position of the shaft 2 corresponds here to the closed state of hybrid circuit breaker, ie the state of transition a permanent current in the circuit breaker. The vacuum switch 1 and the translation axis of the auxiliary shaft 4 are arranged according to the same Y direction substantially perpendicular to the direction of the translation axis X of the main shaft 2, but it is possible to envisage a different angle of 90 ° between these two directions.

The vacuum switch 1, the bore part 8, the piston 4A and the sealing means 17 are of the same type as the corresponding elements in FIG. 1. Preferably, the O-ring which constitutes the sealing means 17 is not in contact with the electrically conductive portion 4A2 in the form of a sleeve of the piston 4A, and is arranged in a housing of the part which forms the bore 8 so as to be in permanent support against an annular element 27 mounted with sealing on this part 4A2. The annular element 27 is not necessarily electrically conductive, and is provided to be able to be moved in abutment against the O-ring without significantly affecting the quality of the seal. The leakage rate of the gaseous insulating fluid G ₂ to the volume V ₁ of gaseous insulating fluid G ₁ can thus be maintained at a very low level over a year of operation of the hybrid circuit breaker.

Ideally, it will be sought for the amount of gas G ₂ fleeing to the volume V ₁ a mean value in time substantially equal to the loss of the gas G ₁ from the volume V ₁ to the outside of the insulating envelope 11. From in this way, if the gases G ₁ and G ₂ are of the same nature or have similar dielectric properties, the pressure P ₁ of gas in the envelope 11 can be maintained within a range of permissible extreme values [P _1min , P _1max ] to maintain the dielectric strength between the two poles of the vacuum interrupter 1 while not exceeding a maximum critical value for the mechanical structure of the switch. For safety, a device for measuring the pressure P ₁ may be provided in particular to control that this pressure remains above the low limit P _1min and prevent the tripping of the hybrid circuit breaker if P ₁ falls below this limit. Conversely, if the critical maximum value P _{1max is exceeded} , a safety device consisting of, for example, a prestressed spring valve 23 may be provided. Such a valve, which can be installed for example in an opening of the metal disk 22 which carries the fixed contact 6 of the vacuum interrupter 1 and which closes the envelope 11, is designed to open slightly in order to allow a clearance towards the atmosphere of a small amount of the gas G ₁ in overpressure relative to the maximum critical value. Of course, this solution assumes that the gas G ₁ does not present a danger to the atmosphere, and it is in this case advantageous to use pure nitrogen.

The difference of the respective pressures P ₂ and P ₁ of the two gaseous insulating fluids G ₂ and G ₁ gives a certain force F p which is applied to the auxiliary shaft 4 and which here by itself provides all the contact pressure force F _c in the same way as for the device of FIG. 1. This force Fp is proportional to the square of the diameter D of the piston.

In a similar way to the switching assembly shown in FIG. 1, the metal casing 7 is open on the side of the gas switch 10 to be tightly assembled with one end of a insulating jacket (not shown) enclosing the switchgear chamber of the gas switch. The housing 7 is one of the two poles of the gas switch 10 being electrically connected to the crew of contacts mobile, not shown, this switch. The part conductor 4A2 of the piston 4A remains in contact electric with bore 8 through contacts 9. The hybrid circuit breaker thus formed is of air-insulated type as well as the device of Figure 1.

The coupling means 3 between the main shaft 2 and the auxiliary shaft 4 comprise a cam 30 which is integral in translation with the main shaft 2 and which can be formed by a section 2A of this shaft 2 as shown in the figure. The surface of the cam 30 is arranged to allow the guidance of an element rolling or roulette 31 which is secured in movement of the auxiliary shaft 4. The axis of this roulette is mounted on a bearing carried by a cradle 4A3 which constitutes a part of the auxiliary shaft 4. This cradle is attached to a part 4A1 inserted into the electrically conductive portion 4A2 of the piston 4A, this part 4A1 is not necessarily conductive since the electrical conduction between bore 8 and the movable contact 5 of the vacuum interrupter is provided by Part 4A2. An end portion 4B of the cradle 4A3 of the auxiliary shaft 4 is adapted to sliding in translation in a guide element 13 which is fixed on a face 7B of the casing 7, this face being opposed to the face which constitutes the wall 7A crossed by the piston 4A of the auxiliary shaft.

Thus, during a tripping of the circuit breaker hybrid to interrupt the current, the training translation of the main shaft 2 along the X axis allows, after a determined dead race, to lead in translation the auxiliary shaft 4 along the Y axis until the complete separation of contacts 5 and 6 of the vacuum interrupter as shown in Figure 4. The dead run of the main shaft 2 is defined here like the distance to travel by the tree, and so also to go through the mobile arc contact of the gas switch, so that the cam 30 comes in contact with the wheel 31 since the closed state of breaker. It is well known that such a race dead is usually needed in a circuit breaker hybrid, so that the arc contacts of the switch gas separate with a certain relative speed substantially at the moment when the separation of Vacuum switch contacts. The dead race is also sometimes called the speeding distance relative arc contacts of the gas switch, and typically corresponds to the lap distance mutual contact of the two arcing contacts of the switch in a configuration of so-called tulip contacts.

The cam and wheel coupling used here between the main shaft 2 and the auxiliary shaft 4 a well-known principle in the field of movement return mechanisms. Such a coupling is otherwise long used for systems coordinated control of multiple switches electric, including a vacuum switch. In In particular, patent document EP0132083 shows a device for operating a switch to empty and a disconnector from a maneuvering shaft of the moving contact of the disconnector moved in translation by a single command. A cam in solidarity translation of this tree is coupled to a roulette wheel integral in translation of the movable contact of the vacuum switch, this switch being arranged perpendicular to the tree. A pressure spring of contact permanently applies a push on the mobile contact of the vacuum switch, allowing to obtain the necessary contact pressure in the switch in the closed position.

The coupling means 3 used in the present control device are therefore analogous to those described in EP0132083. It can be noted that the invention Here, it is advantageous to dispense with the indispensable contact pressure in a conventional control, or allows in any case to decrease the force to be exerted by a spring device mechanics as shown later in the comments Figures 8 and 9. Preferably, in the present control device according to the invention, the roulette 31 and the main shaft 2 are arranged so that that a weak game exists between these two elements in the closed state of the hybrid circuit breaker shown on the figure 3, and also during the course of the race dead by the main shaft when triggering the breaker. Indeed, during the operation of hybrid circuit breaker, it is known that the contacts of the vacuum interrupter may erode under the action of electric arcs during their separation and to lead to thus over time a slight approximation of the contact mobile to the fixed contact in the closed state of the switch. The weak game mentioned above is planned to allow this slight approximation, which also allows no stress caused by force of contact pressure on the auxiliary shaft 4 is not applied to the main shaft 2 in the closed state of the hybrid circuit breaker.

The height of the cam 30 according to the direction of the translation Y axis of the auxiliary shaft 4 is according to the distance e desired for contacts 5 and 6 of the vacuum switch, as shown in Figure 4.

In FIG. 4, the control device of the FIG. 3 is diagrammatically shown in FIG. opening position of the switching assembly. By simplification, the optional scheme for safety against overpressure of gas in the envelope insulation of the vacuum switch 1 is not represented in this figure. From the closed state of the hybrid circuit breaker shown in FIG. tripping of the circuit-breaker is performed by a translation of the main shaft 2 along the X axis towards the right of the figure to separate the arcing contacts of the gas switch 10. After the route of the dead run by the main shaft 2, the part main 30A which corresponds to the so-called slope opening of the cam 30 comes into contact with the roulette 31 for translating the shaft into translation auxiliary 4 along the Y axis down the figure. The moving contact 5 of the vacuum switch adopts well a predetermined motion profile by the shape of the main part 30A. The translation of the tree auxiliary 4 is completed when the route of the roulette 31 leaves the main part 30A of the cam, that is to say when the surface of the cam on which presses roulette back parallel to the direction of the X axis. It is thus possible to continue the mutual distance of the arc contacts from the gas switch after the contacts 5 and 6 of the vacuum switch 1 are completely separated with the desired spacing e, until the end of the circuit breaker function shown in FIG. can be noted that during the opening of the switch to empty 1, the O-ring which constitutes the means 17 remains in permanent support against the annular element 27 with which it ensures the gas tightness of the piston 4A.

In the end position of the circuit breaker function represented in FIG. 4, the wheel 31 is in against the cam 30 by exerting on it a force equal to the force Fp provided by the difference of the respective pressures of the two gases of part and other piston 4A. The main shaft 2 and its cam 30 thus ensure a contact locking role mobile 5 of the vacuum switch in its position opening.

FIG. 5 shows diagrammatically a control device similar to that of FIG. 3, in which the vacuum interrupter is closed again after the end of the circuit breaker function provided by the gas interrupter. The additional travel performed here by the main shaft 2 after the end of the circuit breaker function may allow the switching assembly to provide a disconnector function in addition to the circuit breaker function, since the arc contacts of the circuit breaker function The gas interrupter may be sufficiently far apart to provide a separation distance in the gaseous insulating fluid G ₂ of the switch. The section 2A of the main shaft 2 on which the cam 30 is formed is elongate with respect to the drawing of the cam of the device of FIGS. 3 and 4, so as to provide the cam with a secondary portion 30B with a so-called reclosure slope. . This reclosing slope is inclined in the opposite direction to the opening slope of the main part 30A of the cam.

During the extra race carried out by the main shaft 2, the slope profile of the part secondary 30B allows the wheel 31 and therefore to the auxiliary shaft 4 to get closer to the fixed contact of the vacuum interrupter so that the moving contact come and press this fixed contact with a speed almost instantaneous at the moment of impact. The same contact pressure force as that corresponding to the closed state of the hybrid circuit breaker is applied on the movable contact of the switch to empty after its reclosing. The reclosing allows to prevent the parts electrically connected to the mobile contact of the vacuum interrupter be at a floating potential when the circuit breaker -sector hybrid is in sectioning position because such a floating potential could damage the switch to empty in certain configurations of the line that is severed by the switching assembly.

In Figure 6 is shown schematically a control device similar to that of Figure 5, in an application for a shielded switching assembly. It may be noted that in this type of application, the casing 7 which is at the potential of the high voltage in operation must be electrically insulated from the sealed metal casing 42 which constitutes the shielded vessel of the switching assembly. Because this sealed tank encloses the gaseous insulating fluid G ₂ of the gas circuit breaker at a certain pressure P ₂ , it is not essential that the casing 7 is also gas-tight, except for providing, for example, a gas pressure. higher in the crankcase than in the space remaining between this crankcase and the tank. In the present application, the housing 7 is open, and has the same role of electrical conductor and mechanical support in the control devices according to the invention shown above for air-insulated switchgear assemblies.

The main shaft 2 and its cam 30 are provided to allow the switching assembly to provide a disconnector function in addition to the circuit breaker function. Optionally, a conductive portion of the main shaft 2 is electrically connected to the casing 7 by sliding contacts and is provided at its outer end to the housing of a stud 2B on which is articulated an insulating rod which forms a portion 2C of the shaft 2 and which crosses with sealing the tank 42 of the shielded assembly to be connected to a not shown control mechanism. The pad 2B is arranged to come into electrical contact with a terminal 43 fixed to the tank 42 and through which the insulating rod 2C of the shaft 2 passes, thanks to an additional stroke of the shaft 2 after the end of the disconnecting function. The casing 7 is thus potential-ground to the tank 42, via the conductive part of the main shaft 2. This makes it possible to ground the shielded line which is connected to the fixed contact of the vacuum switch, since this switch was closed at the end of the circuit breaker function and therefore its fixed contact is electrically connected to the housing 7. The central conductor 50 of the shielded line is here immersed in the gas G ₁ surrounding the sealed chamber of the vacuum switch and whose pressure P ₁ is lower than the pressure P ₂ of the gas G ₂ surrounding the gas switch. The switching assembly thus produced is a shielded hybrid switch-breaker which can provide an additional grounding function on one side of the line.

Figure 7 schematically represents another control device according to the invention, shown in the closed state of the switching assembly. The tree auxiliary 4 is identical to that of the Figure 3. It is similarly roulette 31 provided to be displaced by a cam, and is likewise able to slide in translation in a guide element 13 fixed on the casing 7. The means coupling between the main shaft 2 and the shaft auxiliary 4 here use a rotary cam 14 'for act on the wheel 31. The rotation shaft 48 of the cam 14 'is mounted on bearings fixed to the casing 7, and is integral in rotation with a wheel 32 which comprises a circular toothing meshing with a rack 21 carried by the main shaft. translation of the main shaft causes the rotation cam 14 'whose profile is intended to act on roulette 31 after a certain dead race of the main tree, in a coordinated way with the separation of the contacts of the gas switch.

The dielectric medium around the sealed chamber of the vacuum interrupter is constituted here by a dielectric material 28 molded around this chamber and contained in an insulating envelope 11. In known manner, the insulating envelope 11 could as well be constituted by the dielectric material 28 overmolded if this material has sufficient mechanical rigidity and weather resistance. Only a small volume V ₁ of gaseous fluid G ₁ is adjacent to the sealed chamber of the vacuum interrupter, between the flange of the chamber traversed by the moving contact of the switch and the bore part 8 in which can slide the piston 4A of the auxiliary shaft 4. The gas G ₁ is not necessarily insulating, since it has no role of dielectric insulation to ensure between the poles of the vacuum switch, and it It is not necessary to control the pressure of this gas since a possible leak would not have any consequences on the dielectric insulation between the poles.

Sealing means 26 are provided here to prevent any communication between the volume V ₁ and the outside atmosphere, and the gas G ₁ is filled at a pressure higher than the atmospheric pressure so that a possible leakage of the volume V _{1 is} carried out in one direction towards the outside atmosphere. This provision aims to maintain a volume V ₁ free of moisture and dust of the outside atmosphere. Preferably, the gas G ₁ is filled at the factory, during assembly of the switching assembly, at a pressure for example of the order of twice the atmospheric pressure and which corresponds to the temporary filling pressure of the gas G ₂ in the casing 7 for the safe transport of the switching assembly before final on-site filling for operation. It is therefore not necessary to fill and control the volume V ₁ after the switching assembly is out of the factory, which is significant for the operator. It may be noted that the sealing means 26 are not essential, since it would be acceptable for the volume V _{1 to} be filled with air in communication with the outside atmosphere if the flange which is traversed by the moving contact of the switch vacuum is provided to operate in such a configuration.

The bore part 8 comprises a radial orifice 24, which communicates the external atmosphere with an interstitial space between the piston 4A and the bore 8 and which opens into this interstitial space between the sealing means 17 and the switch in a vacuum, so that a possible leakage of the gas G ₂ of the volume V ₂ of the casing 7 through the sealing means 17 is discharged to the outside atmosphere. Thus, such a leakage of the gas G _{2 would} not cause an increase in the gas pressure in the volume V ₁ , and it is therefore unnecessary to install between this volume and the external atmosphere a safety device such as a valve. overpressure evacuation as the valve 23 of the device of FIG. 3. The radial orifice 24 constitutes in itself a safety evacuation in case of leakage of the gas G ₂ through the sealing means 17.

Figures 7a and 7b represent very schematically the principle of maneuvering the contact mobile vacuum switch thanks to the cam rotating 14 '. Figure 7a shows the configuration of Figure 7, in which the contacts of vacuum switch 1 are closed. In practice, we can note that a weak game is needed between the rolling surface of the wheel 31 and the surface of the arcuate portion of the cam 14 'which corresponds to the course of the dead race.

Figure 7b corresponds to the configuration of the Figure 7 after a tripping of the hybrid circuit breaker and at the moment when the vacuum switch contacts are completely separated with the desired distance e. The cam has made a rotation of almost 180 ° here, which can be pursued while maintaining the distance e. It can be noted that the profile of the cam would allow a reclosing of the vacuum interrupter by an additional run of the main shaft 2 and provided of course that the rack 21 has a sufficient length.

The coupling by a rotary cam allows a result similar to that obtained by a coupling using a cam in translation as in the control device of Figure 3. The device for control of Figure 7 can present as advantages on the one hand to be able to reduce the relative speed of impact between the respective surfaces of the cam 14 'and roulette 31 at the end of the dead race, and on the other hand to significantly reduce the efforts transverse forces exerted on the main shaft 2, which allows in particular to limit the wear of the elements of longitudinal guide of the shaft. However, such coupling is more expensive to achieve than coupling using a cam in translation.

The control device shown schematically in Figure 8 constitutes a improvement of the control device of the figure 3. Mechanical means of elastic compression are indeed added to enhance the contact pressure in the closed position of current flow in the switching assembly. These compression means elastic include a spring 35 which is mounted prestressed on the auxiliary shaft 4 according to the direction of the Y axis of the tree. This spring 35 has a end that is in support against a pusher element 34 housed in an abutment member 34 'fixed to the cradle 4A3 of the shaft 4, and has another end which is in support against the piston 4A of the shaft. This pusher element 34 is able to be moved closer to the other end of the spring 35, detaching from its stop position maintained by the member 34 ', when a compression of low amplitude of the spring 35 is performed under the action of a finger 33 which is attached to the main shaft 2 and which is here provided to be able to slide in support against the pusher element 34.

Such compression of the spring 35 makes it possible to apply to the auxiliary shaft 4 a force which is added to the differential pressure force Fp provided by the difference in the respective pressures of the two gaseous insulating fluids, and which reinforces the pressure force. contact F _c in the closed position of the switching assembly, that is to say the closing position of the switching device in the gas. Such a configuration can be advantageous if the force Fp proves insufficient to ensure by itself the contact pressure force F _c necessary to withstand the electrodynamic forces tending to move the contacts of the vacuum switch in the case of a short circuit current. This configuration may indeed be preferred to the alternative which would be to increase the diameter of the piston 4A to increase the differential pressure force, because it allows to maintain a minimum value of contact pressure force even in case of significant gas leakage from the volume of the gas switch. Such a minimum value of contact pressure force provided by a mechanical spring would make it possible to keep the switching assembly in operation in its closed position in order to pass a nominal current, even in the unlikely event that the volume the gas switch would be reduced to atmospheric pressure due to a very large gas leak. There would thus be no repulsion (with separation) of the contacts of the vacuum interrupter and arcing of arcs between the contacts, provided that said minimum value of contact pressure force exceeds the minimum value required for a rated current specified.

Thus, the addition of a spring system mechanics to enhance contact pressure in a control device according to the invention can constitute an appreciable security in terms of safety and business continuity of all of switching provided with the control device. other configurations than that of the device of Figure 8 for such complementary spring systems can be considered, and the energy mechanical spring or springs can be set contribution to participate in separation work complete vacuum switch contacts, as shown in the following.

A complementary system with mechanical springs is shown diagrammatically in FIG. 9, allowing an improvement of the actuating mechanism of the moving contact of the switchgear in the as shown in FIG. 3. This system complementary has mechanical means of elastic compression that include two springs 36 and 37 each acting on a pivoting arm of which one end has a wheel arranged to support against a profiled running surface on the cradle 4A3 of the auxiliary shaft 4, the side of the end 4B of the shaft 4 which can slide in translation in a guiding element 13 'fixed to the housing.

This complementary spring system is shown in enlargement in Figure 9a. The two pivoting arms 38 and 39 each carry a wheel 40 and 41 respectively. The two profiled rolling surfaces on the cradle 4A3 are here symmetrical, as are the provisions of the springs 36 and 37 and the pivoting arms. In the closed position of the switching assembly, the resulting force F _r exerted by the spring system is directed along the Y axis of the auxiliary shaft 4, due to the symmetry of the arrangement of the system with respect to this axis. The profile of the rolling surfaces on the cradle 4A3 is provided so that the resulting force F _r is directed in the same direction as the differential pressure force F _p , thus participating in the contact pressure force F _c which is equal to the sum Fp + F _r . This profile is also designed so that the force F _r changes direction along the Y axis, during a displacement of the auxiliary shaft 4 consecutive to a maneuver of the main shaft 2 for opening or closing the switching assembly.

The change in direction of the force F _r is visible in FIG. 9b, which represents the actuating mechanism in the opening position of the switching assembly at the end of the circuit breaker function. Each rolling surface has a profile with a lateral boss, so that the projected component on the Y axis of the force exerted by a spring 36 or 37 on the auxiliary shaft 4 vanishes to change direction when the contact between a wheel 40 or 41 and the running surface passes the top of the lateral boss. The top of such a boss is defined as the zone of the boss furthest from the Y axis. Thus, when the roller 31 carried by the auxiliary shaft 4 passes through the main part 30A of the cam 30 causing the displacement of the shaft, during an opening or closing of the switching assembly, the force F _r decreases in absolute value to cancel and change direction.

During the opening of the switching assembly, the force F _r changes direction to oppose the differential pressure force Fp. It may be noted that such a change of direction makes it possible to reduce somewhat the work to be performed by the control mechanism of the main shaft 2 for complete opening. It is understood that the energies of the springs as well as the profiles of the lateral bosses are provided so that the force F _r remains lower than Fp in absolute value, so that the auxiliary shaft 4 is always subjected to a resultant force equal to the sum of the mechanical and pneumatic forces which is directed towards the vacuum interrupter to allow a closing (or reclosing) of the contacts of the switch.

Figure 9c schematically shows another improved actuation mechanism of the movable contact of the switchgear in a vacuum. The result is similar to that provided by the actuating mechanism of Figure 9, and allows to a lesser extent to increase the contact pressure in this apparatus without increasing the maneuvering energy required for the control device. The two identical springs 36 and 37, arranged symmetrically with respect to the Y axis, each have a first end articulated in rotation on a fixed support, and a second end articulated in rotation on the auxiliary shaft. The change of direction of the force F _{r is} effected when the two springs are simultaneously oriented in the same direction perpendicular to the axis Y of the auxiliary shaft, which occurs in practice when the tree has traveled most of the stroke e for the desired spacing of the contacts of the vacuum switch.

In Figure 9d is schematically shown another improved actuation mechanism of the movable contact of the switchgear in the vacuum, which advantageously combines the two previous solutions. The cradle 4A3 of the auxiliary shaft 4 comprises a single profiled running surface on which is supported a wheel mounted at one end of a pivoting arm. As for the solution described with reference to FIGS. 9, 9a and 9b, one end of a spring 37 acts on this pivoting arm, and the profile of the rolling surface has a lateral projection designed so that the projected component on the Y axis of the force exerted by the spring 37 on the auxiliary shaft 4 can be canceled to change direction. The cradle 4A3 also has a pivoting hinge attached to one end of another spring 36 as in the solution described with reference to Figure 9c. The spring 36 has a lower energy than the spring 37, and the resulting force F _r exerted by the two springs on the shaft 4 has a component F _r X which is oriented towards the gas switch, along the axis of X translation of the main shaft 2.

This orientation of the component F _r X makes it possible to reduce the instantaneous forces at the contact surface 13'A between the end 4B of the shaft 4 and the guide element 13 'fixed to the casing 7. These instantaneous forces are indeed relatively important when the cam 30 comes into contact with the wheel 31 during an opening operation of the switching assembly, due to the instantaneous speed of several meters per second for the translation of the main shaft 2, and a fortiori if the opening slope of the main portion 30A of the cam 30 is relatively pronounced. It may be noted that the presence of the pivoting spring 36 is not essential, and its main role is to reinforce if necessary the component F _r Y of the resultant force F _r along the Y axis while decreasing the component F _r X.

FIG. 10 diagrammatically shows an alternative embodiment of the gaseous insulating fluid sealing means G ₂ of the gas switch and whose pressure P ₂ is used for the operation of a control device according to the invention. There is no provision for gas sealing means in the interstitial space 49 between the piston 4A 'and the bore part 8' which carries the sliding contacts 9. The piston essentially has a role of mechanical guiding of the auxiliary shaft 4 and electrical conduction between the movable contact of the vacuum switch and a conductive plate 20 electrically connected to a pole of the gas switch, this plate 20 may constitute a face of a metal housing as referenced 7 in the previous achievements. The vacuum switch is surrounded by a gas G ₁ which is distributed on both sides of the piston 4A 'with substantially the same pressure P ₁ . The piston 4A 'may comprise a passage formed by a small channel 25, but such a channel is not normally necessary because even a relatively slow equalization of the pressure of the gas G ₁ between the two sides of the piston is effected by the interstitial space 49 not gas tight. Preferably, a device 45 for measuring the pressure P ₁ is provided in particular to control that this pressure remains above the low limit P _1min .

The wall 7 'which separates the two gaseous insulating fluids G ₁ and G ₂ is sealingly sealed to the conductive plate 20, and has a flexible zone in the center of which is provided an opening which is traversed with sealing by the auxiliary shaft 4 This wall 7 'is in the form of a sealing bellows, and may be made from a metal provided to provide sufficient flexibility and mechanical strength. It preferably has the shape of a disk open at its center for the passage of the shaft 4. Its diameter may be much greater than the diameter of the piston 4A ', the latter can also be decreased as the electric conduction section by the sliding contacts 9 remains in adequacy with the current to be passed through the switching assembly. By increasing the diameter of the wall 7 ', it is possible to obtain a differential pressure force Fp greater than that which would be obtained by a sealed piston control device as represented for example in FIG. 3, this comparison being made hearing for substantially equal moving masses between the two control devices. In addition, since in a bellows-type solution, there is no movable surface relative to a seal, it is possible to obtain a very good seal at the sealed connection between the bellows and a movable assembly as constituted here by the auxiliary shaft 4.

The leakage rate of the gas G ₂ at the pressure P ₂ to the volume V ₁ of the gas G ₁ at the pressure P ₁ is normally negligible, and the quantity of gas G ₂ passing in this volume V ₁ will normally always be lower than the quantity of gas G ₁ can leak from this volume to the outside of the insulating envelope 11. There is therefore in principle no risk that the pressure P ₁ increases until exceeding the maximum value P _1max critical for the mechanical structure of the vacuum switch, and it is a priori not necessary to provide a safety device such as a valve for discharging gas G ₁ overpressure. However, for absolute safety, it can be provided between the volume V ₁ and the outside atmosphere an economic gas evacuation device, consisting of a rupture disk 46 also sometimes called frangible disk and intended to break when the difference gas pressure between the two sides of the disc exceeds a determined breaking value. This rupture disk 46 is mounted here on a metal annular piece 44 which electrically connects the bore piece 8 'to the conductive plate 20, and which also contributes to the seal between the volume V ₁ and the external atmosphere.

An alternative embodiment of the preceding control device of FIG. 10 is shown diagrammatically in FIG. 11. This variant comprises a safety space at atmospheric pressure that operates on the safety principle used in the control device of FIG. 7. Indeed, in the case where the wall 7 ', which has a particular role of sealing bellows with respect to gas G ₂ of the gas switch, would not provide a perfect seal, any gas leak G ₂ through this bellows would be discharged to the outside atmosphere via a channel 24. The volume V ₁ which is between the wall 7 'and the piston 4A of the auxiliary shaft communicates with the outside atmosphere through the channel 24, and the G ₁ gas contained in this volume V ₁ is here atmospheric air.

As for the switching assembly of FIG. 7, a dielectric material 28 is overmoulded around the sealed chamber of the vacuum interrupter. The gas G ₀ of the volume V ₀ between the material 28 and the piston 4A is similar to the gas G ₁ used for the device of FIG. 7, and what has been said previously with respect to this gas remains valid for the present configuration. . The piston 4A has no role here to generate the necessary contact pressure force in the vacuum interrupter. On the contrary, since the gas G ₀ is at a pressure preferably greater than atmospheric pressure, the differential pressure between the two sides of the piston generates a force which tends to oppose (while still much lower) the differential pressure force generated by the gas G ₂ on the flexible wall 7 '. Preferably, the diameter of the piston 4A will be provided as small as possible, provided that the electrical conduction section through the sliding contacts 9 remains sufficient. It may be noted that the sealing means 26 and the annular sealing element 27 are not necessarily indispensable and that the gas G ₀ could then be atmospheric air, as explained previously in connection with the device of FIG. 7.

The control devices that have been described in the above have been shown in applications to switching sets involving each time a vacuum interrupter associated with a gas switch. However, it is understood that control device according to the invention can be applied to switching assembly including a first and / or a second switching device would consisting of several arranged switches electrically in series or in parallel. For example, it is known that a switching assembly can understand a switchgear in the vacuum consisting of several vacuum switches mounted in parallel with their mobile contacts in solidarity movement by being connected to the same auxiliary shaft movable in translation.

Claims (16)

Control device for the coordinated actuation of at least two switchgear units which are electrically connected in series to constitute a switching assembly of which a first switchgear (1) in vacuum comprises a pair of contacts (5, 6) separable for switching between a closed position and an open position, comprising a main operating shaft (2) for actuating a second switching device (10) immersed in a gaseous insulating fluid (G ₂ ) contained in a certain volume (V ₂ ) at a determined pressure (P ₂ ), further comprising an auxiliary shaft (4) adapted to be displaced by coupling means (3) to allow the operation of a movable contact (5) of the first switching (1) during a displacement of said main shaft (2), said movable contact (5) being held in abutment against the other contact (6) of said first device (1), in the closed position of this apparatus, by force (F _c ) designed to produce a contact pressure greater than a predetermined value, characterized in that said auxiliary shaft (4) passes through a wall (7A, 7 ') separating said volume (V ₂ ) from an insulating fluid (G ₂ g) of another volume (V1) of fluid (G ₁ ) at a lower pressure (P ₁ ), the difference of the respective pressures (P ₂ , P ₁ ) of the two fluids (G ₂ , G ₁ ) providing a certain force (Fp) which is applied to said auxiliary shaft (4) and which participates in said contact pressure force (F _c ). A control device according to claim 1, wherein a portion of said auxiliary shaft (4) consists of a piston (4A) displaceable within a bore (8) formed by a workpiece which is mounted sealingly on an opening of said wall (7A), sealing means (17) to said insulating fluid (G ₂ ) gas being arranged between said piston (4A) and said bore (8). Control device according to the claim 2, wherein said wall (7A) and said bore (8) constitute an electrically conductive assembly connected to a pole of the second switching device (10), said piston (4A) has at least one portion (4A2) electrically conductive connected to the moving contact (5) of the first switching device (1), and sliding contacts (9) are arranged between said bore (8) and said conductive portion (4A2) of piston. Control device according to one of claims 1 to 3, wherein said wall (7A) is constituted by a face of a housing (7) which encloses at least a portion of said volume (V ₂ ) of insulating fluid (G ₂ ) and in which are disposed said coupling means (3). Control device according to the claim 4, in which the auxiliary shaft (4) has a end portion (4B) adapted to slide in translation in a guide element (13, 13 ') which is fixed on a face (7B) of the housing (7) opposite the face constituting said wall (7A). Control device according to one of Claims 1 to 5, in which the main shaft (2) has a section (2A), one side of which has a surface arranged to form a guide cam (30) a rolling element (31) which is secured in movement of the auxiliary shaft (4). Control device according to one of claims 1 to 6, wherein said coupling means (3) comprise mechanical elastic compression means able to exert a force on said auxiliary shaft (4) to participate in said contact pressure force (F _c ) in addition to the force (Fp) obtained by the difference of the respective pressures (P ₂ , P ₁ ) of the two fluids (G ₂ , G ₁ ). Control device according to the claim 7, wherein said elastic compression means comprise a spring (35) which is mounted on the shaft auxiliary (4) and one end of which is supported against a pusher element (34) capable of being compressed under the action of a finger (33), said finger being fixed said main shaft (2) and arranged to press against said pusher member (34) in the position of closing the second switching device (10). A control device according to claim 7, wherein said elastic compression means comprises at least one spring (36, 37), the resultant force (F _r ) exerted by said compression means on said auxiliary shaft (4) being provided to change of direction in the direction of the translation axis (Y) of said shaft, during a displacement of said shaft for the opening of the first switching device (1), while remaining lower than the force (Fp) provided by the difference of the respective pressures (P ₂ , P ₁ ) of the two fluids (G ₂ , G ₁ ). Control device according to the claim 9, wherein said spring (36, 37) acts on an arm pivoting member (38, 39) having one end wheel (40, 41) arranged to press against a profiled running surface on said shaft auxiliary (4). Control device according to one of claims 9 and 10, wherein said resultant force (F _r ) has a component (F _r X) which is permanently oriented towards the second switching device (10) in the direction of the translation axis (X) of the main shaft (2) for maneuvering A control device according to claim 2, wherein said bore (8) has a radial orifice (24) which communicates the external atmosphere with an interstitial space between the piston (4A) and the bore (8), said radial orifice (24) opening into said interstitial space between said sealing means (17) and the first switching device (1), so that a possible gas leak (G ₂ ) through the sealing means ( 17) is evacuated to the outside atmosphere. Control device according to the claim 1, wherein said wall (7 ') is sealed to a conductive plate (20) electrically connected to a pole second switching device (10) and has a flexible area in the center of which is provided a opening which is traversed with sealing by said auxiliary shaft (4). Control device according to the claim 13, wherein said auxiliary shaft (4) comprises a piston (4A, 4A ') adapted to be moved within a bore (8, 8 ') electrically connected to said plate conductor (20), and in which sliding contacts (9) are arranged between said piston and said bore. Control device according to claim 14, wherein sealing means (26) are arranged between said piston (4A) and said bore (8), and wherein said other volume (V ₁ ) is provided between said piston (4A). ) and said wall (7 '), this volume (V ₁ ) being in communication with the external atmosphere to be filled with air substantially at atmospheric pressure. Control device according to one of claims 1 to 11 and 13 to 15, wherein said fluid (G ₁ ) of said other volume (V ₁ ) is a gas and wherein a safety device consisting of a valve (23) or a rupture disk (46) makes it possible to evacuate gas (G ₁ ) towards the outside atmosphere in the case where the pressure (P ₁ ) of this gas exceeds a critical value.

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