Gas passage sealing system

Abstract

Gas passage system for a gas passage opening Gas passage system (1) for a gas passage opening (3) comprising: a shutter (11); a return device (13) configured to apply a return force to the closed position on the shutter (11); a conductive part (15) mechanically linked to the shutter (11) so as to apply an opening force to the shutter (11) when the conductive part (15) is rotating about an axis of rotation in an opening direction; a variable speed drive device (19) configured to move, within slip, the conductive part (15) by a rotating magnetic field, a passage gap (21) being provided between the drive device (19) and the conductive part (15), the passage gap (21) being configured for the passage of a portion of the envelope (7). Figure 1

Description

Title of the invention: Sealing system for a gas passage orifice. Field of the invention

[0001] The present invention relates to a sealing system for a gas passage orifice. Previous art

[0002] It is known to use a sealing system for a gas passage orifice.

[0003] The passage opening is here located inside a sealed area comprising said gas and delimited by an envelope.

[0004] Such an enclosure is, for example, included in a gas flow control valve containing dihydrogen as the gas. The enclosure is necessary for dihydrogen tightness but may hinder the installation of the shut-off system.

[0005] Among the existing solutions, it is possible to use a shuttering system comprising a shaft passing through the casing mechanically linking an external drive motor and an internal shutter of the shuttering system.

[0006] Another possibility is to provide a magnetic "gear" type coupling in which the rotational speed of the shutter is synchronized with that of the rotary motor.

[0007] Although these solutions allow the components of a sealing system to be installed on both sides of the wall of the envelope, they remain difficult to implement to ensure good sealing or to ensure compatibility with dihydrogen.

[0008] Furthermore, existing solutions require servo control of the rotor driving the shutter to obtain the desired flow rate. The shutter system must therefore include a position sensor.

[0009] The rotary motor must also stop its rotation to hold the shutter in position once the flow rate is set. This stopping of the rotary motor's rotation means that a current must be supplied to it to balance the load torques and friction involved.

[0010] At zero rotational speed, while receiving current, the rotary motor cannot utilize its own ventilation to limit heating. This thermal issue may necessitate oversizing the rotary motor.

[0011] It therefore appears necessary to design a simplified closure system in its operation to regulate and maintain the flow rate by controlling the opening of the shutter.

[0012] Ideally, the casing should not be penetrated by any element of the sealing system to reach the shutter in order to ensure better sealing. The materials used must also be compatible with dihydrogen.

[0013] The present invention aims to resolve all or part of the disadvantages mentioned above. Description of the invention

[0014] To this end, the present invention relates to a sealing system for a gas passage orifice, the passage orifice being located inside a sealed zone comprising said gas, the sealed zone being delimited by an enclosure, the sealing system comprising:

[0015] a shutter configured to generate a variable passage cross-section in the passage orifice between a closed position in which the passage cross-section is zero and a fully open position in which the passage cross-section is maximal,

[0016] a return device configured to apply a return force to the shutter in the closed position,

[0017] a conductive part mechanically linked to the shutter so as to apply an opening force to the shutter when the conductive part is rotating around an axis of rotation in an opening direction,

[0018] a variable speed drive device configured to move, with minimal slippage, the conductive part by means of a rotating magnetic field, a passage gap being provided between the drive device and the conductive part, the passage gap being configured for the passage of a portion of the envelope so that the envelope is able to encompass the shutter, the return device and the conductive part.

[0019] The conductive part is configured to be rotated by eddy currents without mechanical link between the drive device and the conductive part.

[0020] This configuration allows the shutter, the return device and the conductive part to be placed inside the envelope and the drive device outside the envelope.

[0021] It is thus possible to control the opening of the shutter by increasing the opening force and to close the shutter by decreasing the opening force. The use of two opposing forces applied to the shutter allows for open-loop control. The modulation of the variable speed generates a The opening force, and therefore the gas flow rate through the orifice, is modulated. No sensor is needed to determine the position of the shutter, as it is directly deduced from the opening force value.

[0022] The shuttering system is simple in design, since no sensor is involved in defining the position of the shutter. This simple design and the mechanical decoupling between the conductive part and the drive device are optimal for controlling the sealing of an internal passage in a housing delimiting a sealed zone.

[0023] According to one aspect of the invention, the variable speed drive device is configured to operate at a non-zero equilibrium speed at which the conductive part is driven in rotation so as to obtain an opening force equal to the restoring force to maintain the passage section constant.

[0024] When the restoring force and the opening force have different values, the passage area varies. When these two forces are equal, equilibrium is reached and the passage area remains constant.

[0025] This arrangement makes it possible to maintain a constant gas flow by adjusting the drive device to equilibrium speed when the desired passage section is reached.

[0026] Furthermore, when the passage area is set and the equilibrium speed is maintained, it is not necessary to control the drive mechanism to keep the passage area constant: it is sufficient to maintain the same rotational speed. The shutter's role is to cut off and vary the gas flow, leaving a larger or smaller passage area during its rotation. The passage area is zero when the flow is cut off.

[0027] For example, the shutter can be a butterfly or a spherical plug.

[0028] According to one aspect of the invention, the shutter is capable of being moved by rotation. In In this case, the terms restoring force and opening force are to be understood as being equivalent to the terms restoring torque and opening torque.

[0029] Indeed, the control of the drive torque of the conductive part is achieved by the rotational speed of the rotating magnetic field, via the speed of the drive device.

[0030] According to one aspect of the invention, the drive device comprises a plurality of poles of alternating polarities distributed in a circle around the axis of rotation, the plurality of poles being opposite a complementary portion of the conductive part so that the rotating magnetic field remains present within the conductive part.

[0031] It thus appears that the passage interval is provided between the plurality of poles and the conductive part.

[0032] The rotation of the plurality of poles creates the rotating magnetic field which is variable within the conductive part, resulting in the creation of eddy currents in the conductive part (Lenz-Faraday law).

[0033] The intensity of these eddy currents is proportional to the rotating magnetic field created by the plurality of poles and to the difference in rotational speed between the plurality of poles and the conductive part. These eddy currents interact with the rotating magnetic field, creating a driving torque on the conductive part.

[0034] According to one aspect of the invention, each pole is included in a magnet of the drive device attached to a rotating shaft of the drive device.

[0035] The driving of the conductive part by the rotating magnets results from the interaction between the rotating magnetic field created by the magnets and the eddy currents induced in the conductive part, via the relative motion between the magnets and the conductive part. The driving is contactless and viscous, which allows for a difference in speed between the rotation of the magnets and that of the conductive part.

[0036] According to an alternative, the drive device comprises a three-phase inverter associated with a three-phase winding, of the stator type of an asynchronous motor.

[0037] The rotating magnetic field created by the association of the three-phase inverter and the three-phase winding, of the stator type of an asynchronous motor, also makes it possible to drive the conductive part in rotation.

[0038] According to one aspect of the invention, the drive device comprises a rotary motor configured to move the shaft rotating around the axis of rotation in the direction of opening, the movement of the rotating shaft generating, except for slippage, the rotation of the conducting part in the direction of opening.

[0039] The rotary motor and the rotating shaft comprising the plurality of poles are located at a distance from the conductive part. This allows the rotation of the conductive part to be controlled remotely through the housing.

[0040] According to one aspect of the invention, the conductive part is made of a material or alloy compatible with the gas used. Preferably, the gas is dihydrogen.

[0041] According to one aspect of the invention, the rotary motor is configured to have a variable rotational speed between a non-zero minimum speed at which the opening force is less than the restoring force and a maximum speed at which the opening force is greater than the restoring force.

[0042] Thus, the rotary motor continues its rotation even when the passage section is closed or reduced. When the shutter is in the closed position, the rotational speed can be the minimum speed or any speed lower than the equilibrium speed. Being at the minimum speed in this case is advantageous because the The rotary motor consumes less power while still rotating so that it does not have to be restarted if it is necessary to open the shutter.

[0043] According to one aspect of the invention, the shutter system is capable of receiving and transferring a command in the form of pulse width modulation or PWM to the rotary motor so as to vary the speed between the minimum speed and the maximum speed.

[0044] According to an alternative, the speed regulation of the electric motor is achievable by a non-switched variable analog voltage control.

[0045] According to one aspect of the invention, each pole is arranged symmetrically with another pole of the same polarity with respect to the axis of rotation.

[0046] The number of poles is thus always even and the plurality of magnets is distributed regularly respecting the symmetry with respect to the axis of rotation.

[0047] The number of poles depends on the size of the shutter and the torque to be exerted on the conductive part.

[0048] In addition to these parameters, the number of magnets is dimensioned according to the rotational speed of the rotating magnetic field, at which the torque to be exerted on the conductive part is reached.

[0049] Since the phenomenon can be non-linear, the dimensioning is generally carried out via the support of magnetic finite element simulations in transient mode.

[0050] According to one aspect of the invention, the conducting part is a disk extending transversely to the axis of rotation.

[0051] In this case, the rotating shaft has a transverse bearing surface to the axis of rotation on which the poles are attached.

[0052] The advantage of using a disc-shaped conductive part is that the rotary motor can have a different axis of rotation from the axis of rotation of the conductive part by using a suitable motion transmission mechanism.

[0053] Furthermore, the portion of the envelope disposed between the plurality of poles and the conductive part can be flat.

[0054] According to one aspect of the invention, the conducting part is a cylinder.

[0055] In this case, the plurality of poles is arranged around the cylinder on an internal cylindrical surface of the rotating shaft.

[0056] The advantage of using a cylindrical conductive part is to have a higher torque density.

[0057] The portion of the envelope disposed between the plurality of poles and the conductive part has an advance extending along the axis of rotation so as to include the cylinder.

[0058] According to one aspect of the invention, the conductive part has an electrical conductivity beyond a defined limit so as to allow the appearance of eddy currents in the conductive part.

[0059] The high electrical conductivity, beyond the defined limit, of the conductive part is necessary for actuation by eddy currents.

[0060] Eddy current actuation generates a slip or a difference in rotational speeds between the rotating magnetic field and the driven conductive part, which makes it possible to control the drive torque necessary to move the conductive part.

[0061] For optimal actuation, it is necessary that the electrical conductivity of the conductive part be at least eight times greater than the electrical conductivity of the casing.

[0062] According to one aspect of the invention, the conductive part actuated by eddy currents is made of an alloy compatible with dihydrogen, in particular an alloy of copper and / or aluminum.

[0063] According to one aspect of the invention, the drive device comprises a speed multiplier mounted between the rotary motor and the rotating shaft.

[0064] The main advantage of the speed multiplier is that the driving torque exerted on the conductive part is multiplied. However, this requires that the rotary motor be able to supply a suitable torque.

[0065] According to one aspect of the invention, the rotating shaft comprises at least a portion made of a ferromagnetic material on which the poles rest.

[0066] According to one aspect of the invention, the shuttering system comprises a rotating lever mechanically connecting a conductive part to the shutter. The rotating lever can extend along the axis of rotation so as to actuate the shutter by rotating on itself.

[0067] According to one aspect of the invention, the return device is a return spring arranged to apply the closing force to the shutter.

[0068] The present invention also relates to a machine comprising the casing, the passage orifice and the gas-tight zone, the machine further including the sealing system as described above.

[0069] According to one aspect of the invention, the machine is a gas flow control valve. Preferably, the valve is adapted for regulating the flow of a gas composed of gaseous dihydrogen.

[0070] The different aspects defined above, which are not incompatible, can be combined. Brief description of the figures

[0071] The invention will be better understood with the aid of the detailed description set out below in relation to the accompanying drawings.

[0072] [Fig. 1] is a schematic view representing a machine delimited by an envelope and a shuttering system.

[0073] [Fig.2] is a schematic view of a support and a plurality of poles of the shuttering system.

[0074] [Fig.3] is a schematic view of the support, the plurality of poles and a conductive part of the shuttering system.

[0075] [Fig.4] is a schematic view representing a variant of the machine delimited by an envelope and a variant of the shuttering system.

[0076] [Fig.5] is a schematic view of the variant of the support and the plurality of poles of the shutter system.

[0077] [Fig.6] is a schematic view of the variant of the support, the plurality of poles and the conductive part of the shutter system. Description with reference to the figures

[0078] In the detailed description that will follow of the figures defined above, the same elements or elements fulfilling identical functions may retain the same references in order to simplify the understanding of the invention.

[0079] As illustrated in Figures 1 to 6, a sealing system 1 is intended for closing a gas passage orifice 3. The gas passage orifice 3 is located inside a sealed zone 5 comprising said gas, the sealed zone 5 being delimited by an enclosure 7.

[0080] A machine 9 comprises the casing 7, the passage orifice 3 and the sealed zone 5 for gas, the machine 9 further including the closure system 1. Here, the machine 9 is a flow control valve for gaseous dihydrogen.

[0081] The shuttering system 1 includes a shutter 11 configured to generate a variable passage section in the passage orifice 3 between a closed position in which the passage section is zero and a fully open position in which the passage section is maximum.

[0082] The shutter 11 is here a butterfly or a spherical bushing.

[0083] The shutter system 1 includes a return device 13 configured to apply a return force in the closed position to the shutter 11.

[0084] The shutter system 1 includes a conductive part 15 mechanically linked to the shutter 11 so as to apply an opening force to the shutter 11 when the conductive part 15 is rotating about an axis of rotation 17 in an opening direction.

[0085] The shutter system 1 includes a variable speed drive device 19 configured to move, with minimal slippage, the conductive part 15 by means of a rotating magnetic field.

[0086] A passage gap 21 being provided between the drive device 19 and the conductive part 15, the passage gap 21 being configured for the passage of a portion of the envelope 7 so that the envelope 7 is able to encompass the shutter 11, the return device 13 and the conductive part 15.

[0087] The conductive part 15 is configured to be rotated by eddy currents 23 without mechanical link between the drive device 19 and the conductive part 15.

[0088] This configuration allows the shutter 11, the return device 13 and the conductive part 15 to be placed inside the envelope 7 and the drive device 19 to be placed outside the envelope 7.

[0089] The variable speed drive device 19 is configured to operate at a non-zero equilibrium speed at which the conductive part 15 is driven in rotation so as to obtain an opening force equal to the restoring force to maintain the passage section constant.

[0090] When the restoring force and the opening force have different values, the passage area varies. When these two forces are equal, equilibrium is reached and the passage area remains constant.

[0091] This arrangement makes it possible to maintain a constant gas flow by adjusting the drive device 19 to equilibrium speed when the desired passage section is reached.

[0092] Furthermore, when the passage section is set and the equilibrium speed is maintained, it is not necessary to control the drive device 19 so that the passage section remains constant: it is sufficient to maintain the same rotational speed.

[0093] The purpose of the Lia obturator is to cut off and vary the gas flow, leaving a larger or smaller passage area during its rotation. The passage area is zero when the flow is cut off.

[0094] For example, the shutter 11 can be a butterfly or a spherical plug.

[0095] The shutter 11 is capable of being moved by rotation. Thus, the terms restoring force and opening force are to be understood as being equivalent to the terms restoring torque and opening torque.

[0096] Indeed, the control of the drive torque of the conductive part 15 is achieved by the rotation speed of the rotating magnetic field, via the speed of the drive device 19.

[0097] The drive device 19 comprises a plurality of poles 25 of alternating polarities distributed in a circle around the axis of rotation 17, the plurality of poles 25 being opposite a complementary portion of the conductive part 15 so as to generate the rotating magnetic field.

[0098] It thus appears that the passage interval 21 is provided between the plurality of poles 25 and the conductive part 15.

[0099] The rotation of the plurality of poles 25 creates the rotating magnetic field which is variable within the conductive part 15, which results in the creation of eddy currents 23 in the conductive part 15 (Lenz-Faraday law).

[0100] The intensity of these eddy currents 23 is proportional to the rotating magnetic field created by the plurality of poles 25 and to the difference in rotational speed between the plurality of poles 25 and the conductive part 15. These eddy currents 23 interact with the rotating magnetic field, which creates a driving torque of the conductive part 15.

[0101] Each pole 25 is included in a magnet of the drive device 19 brought onto a support 27 of a rotating shaft 29 of the drive device 19.

[0102] The driving of the conductive part 15 by the rotating magnets results from the interaction between the rotating magnetic field created by the magnets and the eddy currents 23 induced in the conductive part 15, via the relative movement between the magnets and the conductive part 15. The driving is contactless and of the viscous type, which allows a difference in speed between the rotation of the magnets and that of the conductive part 15.

[0103] The drive device 19 includes a rotary motor 31 configured to move the rotating shaft 29 around the axis of rotation 17 in the direction of opening, the movement of the rotating shaft 29 causing, within slippage, the rotation of the conducting part 15 in the direction of opening.

[0104] The rotary motor 31 and the rotating shaft 29 comprising the plurality of poles 25 is distant from the conductive part 15. This allows the rotation of the conductive part 15 to be controlled remotely through the housing 7.

[0105] The conductive part 15 is made of a material or alloy compatible with the gas used. Here, the gas is dihydrogen.

[0106] The rotary motor 31 is, for example, an electric motor.

[0107] The rotary motor 31 is configured to have a variable rotational speed between a non-zero minimum speed at which the opening force is less than the restoring force and a maximum speed at which the opening force is greater than the restoring force.

[0108] Thus, the rotary motor 31 continues to rotate even when the passage section is closed or reduced. When the shutter 11 is in the closed position, the rotation speed can be the minimum speed or any speed lower than the equilibrium speed. Being at the minimum speed in this case is advantageous because the rotary motor 31 consumes less power while still rotating, so that it does not have to be restarted if it is necessary to open the shutter 11.

[0109] Each pole 25 is arranged symmetrically with another pole 25 of the same polarity with respect to the axis of rotation 17.

[0110] The number of poles 25 is thus always even and the plurality of magnets is distributed regularly respecting the symmetry with respect to the axis of rotation 17.

[0111] The number of poles 25 is a function of the size of the shutter 11 and the torque to be exerted on the conductive part 15.

[0112] In addition to these parameters, the number of magnets is dimensioned according to the rotational speed of the rotating magnetic field, at which the torque to be exerted on the conductive part 15 is reached.

[0113] Since the phenomenon can be non-linear, the dimensioning is generally carried out via the support of magnetic finite element simulations in transient mode.

[0114] As illustrated in figures 1 to 3, the conducting part 15 can be a disk extending transversely to the axis of rotation 17.

[0115] In this case, the rotating shaft 29 has a receiving surface 33 transverse to the axis of rotation 17 on which the poles 25 are attached.

[0116] The advantage of using a disc-shaped conductive part 15 is that the rotary motor 31 can have a different axis of rotation from the axis 17 of the conductive part 15 by using a suitable motion transmission mechanism.

[0117] Furthermore, the portion of the envelope 7 disposed between the plurality of poles 25 and the conductive part 15 can be flat.

[0118] As illustrated in figures 4 to 6, the conductive part 15 can be a cylinder.

[0119] In this case, the plurality of poles 25 is arranged around the cylinder on an internal cylindrical surface 35 of the support 27 of the rotating shaft 29.

[0120] The advantage of using a conductive part 15 in a cylinder is to have a higher torque density.

[0121] The portion of the envelope 7 disposed between the plurality of poles 25 and the conductive part 15 has an advance 37 extending along the axis of rotation so as to include the cylinder.

[0122] The conductive part 15 has an electrical conductivity beyond a defined limit so as to allow the appearance of eddy currents 23 in the conductive part 15.

[0123] The high electrical conductivity, beyond the defined limit, of the conductive part 15 is necessary for the actuation by eddy currents 23.

[0124] Eddy current actuation 23 generates a slip or a difference in rotational speeds between the rotating magnetic field and the driven conductive part 15, which makes it possible to control the drive torque necessary to move the conductive part 15.

[0125] For optimal actuation, it is necessary that the electrical conductivity of the conductive part 15 be at least eight times greater than the electrical conductivity of the casing 7.

[0126] The conductive part 15 actuated by eddy currents 23 is made of an alloy compatible with dihydrogen, in particular an alloy of copper and / or aluminium.

[0127] The drive device 19 may optionally include a speed multiplier mounted between the rotary motor 31 and the rotating shaft 29.

[0128] The main advantage of the speed multiplier is that the drive torque exerted on the conductive part 15 is multiplied. However, this requires that the rotary motor 31 be able to supply a suitable torque.

[0129] The rotating shaft 29 includes at least a portion made of a ferromagnetic material on which the poles 25 rest. This portion may correspond to the support 27.

[0130] The shutter system 1 includes a rotating lever 39 mechanically connecting conductive part 15 to the shutter 11. The rotating lever 39 can extend along the axis of rotation 17 so as to actuate the shutter 11 by rotating on itself.

[0131] The return device 13 is, for example, a return spring arranged to apply the closing force to the shutter 11.

[0132] The shuttering system 1 described herein uses two opposing forces applied to the shutter to regulate the gas flow rate. Since the relationship between the opening force and the flow rate is always the same, once calibration has been performed, the shuttering system 1 can operate in open loop.

[0133] No sensor is required to know the position of the shutter 11 because it is directly deducible from the value of the opening force.

[0134] The shuttering system 1 is of simple construction, since no sensor is involved in defining the position of the shutter 11. This simple construction and this mechanical decoupling between the conductive part 15 and the drive device 19 are optimal for controlling the closure of a passage orifice 3 internal to a housing 7 delimiting a sealed zone 5 of a machine 9 such as a gas flow regulating valve.

[0135] As can be understood, the invention is not limited to the single embodiment described above by way of example, but on the contrary encompasses all variants of its realization.

Claims

Demands

1. A sealing system (1) for a gas passage orifice (3), the passage orifice (3) being located within a sealed zone (5) comprising said gas, the sealed zone (5) being delimited by an enclosure (7), the sealing system (1) comprising: - a shutter (11) configured to generate a variable passage cross-section in the passage orifice (3) between a closed position in which the passage cross-section is zero and a fully open position in which the passage cross-section is maximum, - a return device (13) configured to apply a return force to the closed position on the shutter (11), - a conductive part (15) mechanically linked to the shutter (11) so as to apply an opening force to the shutter (11) when the conductive part (15) is rotating about an axis of rotation (17) in an opening direction,- a variable-speed drive device (19) configured to move, with minimal slippage, the conductive part (15) by means of a rotating magnetic field, a passage gap (21) being provided between the drive device (19) and the conductive part (15), the passage gap (21) being configured for the passage of a portion of the envelope (7) so that the envelope (7) is able to encompass the shutter (11), the return device (13) and the conductive part (15).

2. A shuttering system (1) according to claim 1, wherein the variable speed drive device (19) is configured to operate at a non-zero equilibrium speed at which the conductive part (15) is driven in rotation so as to obtain an opening force equal to the restoring force to maintain the passage section constant.

3. A shuttering system (1) according to claim 1 or 2, wherein the drive device (19) comprises a plurality of poles (25) of alternating polarities arranged in a circle around the axis of rotation (17), the plurality of poles (25) being opposite a complementary portion of the conductive part (15) so that that the rotating magnetic field remains present within the conductive part (15).

4. A shutter system (1) according to claim 3, wherein the drive device (19) comprises a rotary motor (31) configured to move the rotating shaft (29) around the axis of rotation (17) in the direction of opening, the movement of the rotating shaft (29) causing, within slippage, the rotation of the conducting part (15) in the direction of opening.

5. A shuttering system (1) according to claim 4, wherein the rotary motor (31) is configured to have a variable rotational speed between a non-zero minimum speed at which the opening force is less than the restoring force and a maximum speed at which the opening force is greater than the restoring force.

6. A shuttering system (1) according to any one of claims 3 to 5, wherein each pole (25) is arranged symmetrically with another pole (25) of the same polarity with respect to the axis of rotation (17).

7. A sealing system (1) according to any one of claims 1 to 6, wherein the conducting part (15) is a disc extending transversely to the axis of rotation (17).

8. A sealing system (1) according to any one of claims 1 to 6, wherein the conducting part (15) is a cylinder.

9. A sealing system (1) according to any one of claims 1 to 8, wherein the conductive part (15) has an electrical conductivity beyond a defined limit so as to allow the appearance of eddy currents (23) in the conductive part (15).

10. Machine (9) comprising the casing (7), the passage orifice (3) and the sealed zone (5) for gas, the machine (9) further comprising the sealing system (1) according to any one of claims 1 to 9.

Images