Annular electromagnetic induction pump

Abstract

The present invention relates to an electromagnetic induction pump, comprising: - a tubular internal sensor including a plurality of internal combs and an internal coil positioned between the teeth of the internal combs, the interior of the internal sensor forming a cavity; - an internal tube positioned around the internal sensor; - a pumping channel allowing circulation of the fluid to be pumped; - an external tube, the channel being located between the internal tube and the external tube; - a tubular external sensor positioned around the external tube and including a plurality of external combs and an external coil positioned between the teeth of the external combs; - the electromagnetic pump further comprising a moving device for moving the internal combs and capable of changing the radial clearance between the internal combs and the internal tube, and including a first portion positioned inside the internal sensor and connected to the internal combs to enable radial movement of the internal combs, and a second portion extending at least partially outside the internal sensor and connected to the first portion in a manner that controls the first portion.

Description

Technical Field

[0001] This invention relates to an electromagnetic pump (which may be referred to as an "EM pump" below), and more particularly to a toroidal EM induction pump, especially high-power electromagnetic pumps typically exceeding 500 kW.

[0002] This invention can be significantly applied in sodium-cooled fast neutron reactors (commonly referred to as "Na FNR"), particularly in the secondary cooling loop of NaFNR. Background Technology

[0003] It is common practice to use electromagnetic pumps to pump liquefied metals. In specific fields where they are used with liquefied metals, such pumps actually offer more advantages than mechanical pumps. Since electromagnetic pumps have no moving parts and therefore no parts requiring lubrication, they do not require lubrication circuits. This provides higher reliability compared to mechanical pumps. Furthermore, the cooling circuits used for electromagnetic pumps advantageously utilize the liquefied metal they are pumping, such as sodium. In this case, electromagnetic pumps are generally defined as passively cooled. Therefore, electromagnetic pumps can limit the number of auxiliary circuits while improving overall reliability.

[0004] Electromagnetic pumps utilize the Laplace force, which is exerted when a conductor (in this example, liquid metal moving through a pumping channel (also simply called the "channel")) is placed in a magnetic field and a current flows through it. In cases where the pump delivers fluid through a heat transfer loop (such as the primary or secondary cooling loop of a nuclear reactor), induction pumps are the only conceivable technology due to the required pumping power. For simplicity, the electromagnetic induction pump will be referred to as an "electromagnetic pump" below. This type of pump operates by inducing a current within the pumping channel through a time-varying electromagnetic field generated by a (sliding or rotating) inductor.

[0005] Patent FR3073972 describes a known annular linear induction pump (commonly known by its acronym "ALIP") and... Figure 1 Recurrence in China.

[0006] Figure 1 The annular electromagnetic induction pump 1 shown includes, starting from the central axis X of the electromagnetic pump:

[0007] - Internal sensor (also known as "internal stator") 10;

[0008] -Inner tube 31 containing internal sensors;

[0009] - Pumping channel 32, in which the fluid to be pumped circulates, the inner wall of the pumping channel is formed by inner tube 31.

[0010] -Outer tube 33, which forms the outer wall of the pumping channel and an external sensor is positioned around the outer tube, the pumping channel being located between the inner tube and the outer tube;

[0011] - An external sensor (also referred to as an "external stator") 20 is positioned around an external tube 33.

[0012] The internal sensor, internal tube, pumping channel, external tube, and external sensor are concentric around the central axis X.

[0013] Each of the internal and external sensors 10 and 20 consists of the following:

[0014] - A set of magnetic laminated stacks 100 and 200 (commonly referred to as comb sections) and individually designated as 101, 102, 103 and 201, 202, 203, respectively.

[0015] Coils 111, 112, 113 and 211, 212, 213 are connected to each other along the central axis X of the electromagnetic pump 1, and each coil has an annular shape wound around the central axis.

[0016] The comb sections 101, 102, and 103 of the internal sensor 10 can be referred to as "internal comb sections". The comb sections 201, 202, and 203 of the external sensor 20 can be referred to as "external comb sections".

[0017] Each comb section is characterized by a peripheral groove or slot, each peripheral groove or slot forming a housing through which the coil passes.

[0018] In order to generate a magnetic field that slides along the main axis, the coils 111, 112, 113 and 211, 212, 213 of the internal and external magnetic inductors 10, 20 are powered by a multiphase (usually three-phase) power grid.

[0019] The electromagnetic pump shown is passively cooled. It is advantageously used in the secondary cooling circuit of a Na-FNR. In this case, and at high temperature levels (typically exceeding 200°C), it is necessary to completely control the heat transfer within the pump. This is because the windings of the internal and external inductors are the source of the heat power from which the heat to be removed originates. This is especially true for the internal inductors, where the only possible heat transfer interface is the internal tube in contact with the sodium, from which the heat is removed and thus transferred.

[0020] In that situation, strict control over the removal of heat from the internal inductors of the electromagnetic pump is absolutely necessary. Generally speaking, heat transfer in the electromagnetic pump must be strictly controlled.

[0021] Patent application JPH10304647 discloses a contact holding system formed of an elastomer for maintaining contact between the comb portion of an (external and / or internal) sensor and the (internal and / or external) tube of an annular electromagnetic induction pump. The elastomer is spring-type and designed to absorb differences in radial thermal expansion between the various components. One drawback of this solution is the inability to adjust the strength of the contact force, especially after the electromagnetic pump has been assembled. Furthermore, once the electromagnetic pump has been assembled, and particularly once the internal sensor has been inserted, it is no longer possible to apply a contact force if the elastomer has not been provided. Additionally, the provided solution may hinder the insertion of the internal sensor into the electromagnetic pump. Finally, the contact force cannot be adjusted without resorting to disassembling the pump.

[0022] Patent JPH11104817 also describes a contact holding system formed by a series of external springs for maintaining contact between the comb portion of a (external and / or internal) sensor and the (internal and / or external) tube of an annular electromagnetic induction pump. The external sensor contact system is adjustable via a screw-nut system that is laterally positioned and applies more or less pressure to the external springs, thus adjusting the force applied to the external tube. The internal sensor can be removed via the upper portion. However, the force provided by the internal springs is not adjustable unless the internal sensor is removed and the contact system is altered.

[0023] Of all the solutions offered, the system for assembling the electromagnetic pump is difficult, and the contact sensing system is long and difficult to adjust, or even impossible to adjust in the case of internal sensors.

[0024] Therefore, there is indeed a need for a system to ensure contact between the sensor and the pumping channel of an electromagnetic pump, especially in the case of an internal sensor in the electromagnetic pump, a system that is easy to implement and can be quickly adjusted to provide the same quality of contact while achieving the same heat removal performance as existing patents, or even better performance.

[0025] Advantageously, the present invention needs to be able to solve this problem without disassembling the pump, while maintaining the ease of assembly of the internal sensors, or even facilitating their assembly.

[0026] In particular, there is a need to provide an electromagnetic pump with improved passive cooling, especially at temperatures above 200°C. Summary of the Invention

[0027] One device capable of overcoming these drawbacks is an electromagnetic induction pump, which has a generally tubular shape extending in the longitudinal direction and includes:

[0028] - A basic tubular internal sensor, comprising a plurality of internal comb sections and at least a plurality of internal coils disposed between the teeth of the internal comb sections, wherein the interior of the internal sensor forms a cavity;

[0029] - An internal tube, positioned around an internal sensor;

[0030] - Pumping channel, which allows the fluid to be pumped to circulate;

[0031] -Outer pipe, the pumping channel is formed between the inner pipe and the outer pipe;

[0032] - A basic tubular external sensor, which is positioned around an external tube and includes a plurality of external combs and a plurality of external coils positioned at least between the teeth of the external combs;

[0033] The electromagnetic pump is characterized in that it further includes a moving device for moving an internal comb section, the moving device being capable of varying the radial gap between the internal comb section and the internal tube between a first gap in which no teeth of the internal comb section contact the internal tube and a second gap in which all or some teeth of the internal comb section contact the internal tube, the moving device comprising a first portion located inside an internal sensor and connected to the internal comb section to enable radial movement of the internal comb section, and a second portion extending at least partially outside the internal sensor and connected to the first portion in a manner that controls the first portion.

[0034] The fluid to be pumped is a conductive fluid, and preferably a liquid metal.

[0035] According to the present invention, the radial gap between the first gap where no teeth in the internal comb contact the internal tube and the second gap where all or some teeth in the internal comb contact the internal tube means that the radial gap can be any value between the first gap and the second gap, including the first gap and the second gap.

[0036] The principle of this invention is to utilize the thermal path formed by all the comb sections of the internal magnetic circuit of the electromagnetic pump. More specifically, the invention allows for close contact between the comb section of the internal sensor (referred to as the "internal comb section") and the internal tube of the electromagnetic pump in order to limit the contact thermal resistance between these components as much as possible, and to achieve this in a manner that is easy to implement and adjust.

[0037] A significant improvement provided by this invention is the possibility of adjusting the contact force (also referred to as "pressing force") of each internal comb against the internal tube, and achieving this without disassembling the pump. Therefore, adjustment can be made by approaching the outside of the pump, while the stationary pump remains in the operating circuit.

[0038] This adjustment is a major advantage for assembling internal sensors within the electromagnetic pump. The ability to adjust the contact force between each internal comb and the internal tube allows for the generation of sufficient contact force to ensure heat transfer, or the reduction or elimination of this contact force, or the creation of an insertion gap by placing the internal comb in a radially retracted position to facilitate the insertion of the internal sensor into the electromagnetic pump.

[0039] This is also a significant advantage regarding the reliability and availability of electromagnetic pumps. Specifically, by easily creating a gap between the internal sensor and the internal tube, the internal sensor becomes faster and easier to replace in case of a defect. This increases availability. Regarding reliability, the ability to change pressure ensures optimal heat exchange throughout the sensor's lifespan, thus limiting its temperature and improving its reliability.

[0040] The present invention also makes it possible to verify that the contact has been correctly achieved and / or that it has not loosened over time.

[0041] The same type of radial movement device can also be applied to external sensors.

[0042] Therefore, this suitable mechanical design of the electromagnetic pump facilitates the dissipation of heat, and this design also significantly facilitates the assembly of the internal sensor inside the electromagnetic pump.

[0043] The mobile device can be broken down into multiple embodiments, including those described below, and these embodiments can be combined with each other unless otherwise indicated.

[0044] According to one embodiment, the second part of the mobile device extends substantially in the longitudinal direction and is capable of moving in the longitudinal direction.

[0045] According to one embodiment, the second part of the mobile device includes a plurality of rods, the first ends of which extend outside the electromagnetic pump and the second ends of which extend into a cavity formed inside the internal sensor. Each rod is mechanically connected between its first and second ends to the first part of the mobile device inside the internal sensor. A rod refers to an elongated component, typically having a uniform and cylindrical cross-section. It can be a bar, a through bolt, etc. The rod is preferably made of metal.

[0046] According to a particular embodiment, the first end of each rod is characterized by having threads, and the moving device further includes a plurality of nuts that can engage with the threads of the first end of the rod, such that rotation of the nuts controls the movement of the rod in the longitudinal direction.

[0047] According to one embodiment, the first part of the moving device includes a plurality of spring plates, which contact an internal comb on one side and a rod on the other. The spring plates are also preferably fixed to the internal comb. Alternatively, this could be some other component that can contact and is preferably fixed to the comb and adapted to radially move the comb during rod movement. Therefore, the component can be a deformable part other than the spring plates, or a part that can deform very little even if deformation occurs, such as a cam-type mechanical component.

[0048] According to a particular embodiment, each bar is characterized by having at least one recess on its outer surface facing the comb portion that engages with a spring plate, such that when the bar moves in the longitudinal direction, the spring plate moves radially between the interior and exterior of the recess, or conversely, between the exterior and interior of the recess, thus causing radial movement of the inner comb portion in contact with the spring plate. The spring plate is deformable to absorb manufacturing and mechanical assembly defects, as well as gap variations during operation, particularly under the influence of dimensional changes caused by temperature levels.

[0049] According to one particular embodiment, the lever is capable of controlling the radial movement of a single internal comb section. According to an alternative embodiment, the lever is capable of controlling the radial movement of several internal comb sections.

[0050] According to one embodiment, the rod is characterized by having a plurality of recesses on its outer surface that can engage with a plurality of spring blades that contact the inner comb portion.

[0051] According to one embodiment, the mobile device further includes a support tube on which the rod is positioned.

[0052] According to one particular embodiment, the rod is positioned uniformly around the support tube.

[0053] According to one particular embodiment, the support tube includes at least one reinforcing ring positioned against the inner wall of the support tube at a location of the recess in the rod.

[0054] According to one particular embodiment, the support tube is characterized by having an additional thickness on its outer wall at the location of the recess in the rod.

[0055] According to one particular embodiment, the support tube includes a guide ring on its outer wall for guiding a rod, the guide ring including an aperture that allows the rod to move in the longitudinal direction.

[0056] According to one embodiment, the moving device further includes a radial guide for guiding the internal comb section.

[0057] Furthermore, according to a particular embodiment, the electromagnetic pump includes an additional moving device for moving the comb section (outer comb section) of an external sensor, which is capable of changing the radial clearance between the outer comb section and the outer tube. All embodiments and variations described regarding the moving device for moving the inner comb section also apply to the moving device for moving the outer comb section. Attached Figure Description

[0058] Other features and advantages of the invention will become apparent from the following description, given in a non-limiting manner with reference to the accompanying drawings, in which:

[0059] Figure 1 A prior art annular electromagnetic induction pump is described.

[0060] Figure 2A and Figure 2B An embodiment of the electromagnetic pump according to the present invention is described.

[0061] Figure 3A and Figure 3B An exploded view of the internal sensor of an electromagnetic pump according to an embodiment of the present invention is depicted.

[0062] Figure 4 The moving device of the electromagnetic pump according to an embodiment of the present invention is described in detail.

[0063] Figure 5A and Figure 5B It depicts a moving device in two different positions.

[0064] Figure 6 The diagram schematically illustrates the heat transfer between the internal sensor and the internal tube. Detailed Implementation

[0065] Describes the prior art annular electromagnetic induction pump Figure 1 As already described above, this will not be reconsidered here.

[0066] Figure 2A , 2B 3A and 3B describe one embodiment of the electromagnetic pump according to the present invention, and Figure 3A and 3B The pump's internal sensors are described in detail. Figure 4 The moving device of the electromagnetic pump according to the embodiment is described in detail. Figure 5A and 5B The image depicts a moving device in two different radial positions.

[0067] The electromagnetic pump is a ring-shaped electromagnetic induction pump, which is based on... Figure 1The prior art electromagnetic pump shown follows the same manner, starting from the central axis X (which is also the longitudinal direction) of electromagnetic pump 1:

[0068] -Internal sensor (or internal stator) 10;

[0069] -Internal tube 31, which contains an internal sensor;

[0070] - Pumping channel 32, in which the fluid 2 to be pumped can circulate, and the inner wall of the pumping channel is formed by an inner tube 31;

[0071] - External pipe 33, forming the outer wall of the pumping channel;

[0072] - An external magnetic sensor (or external stator) 20 is positioned around an external tube 33.

[0073] Therefore, the pumping channel 32 is formed between the inner pipe 31 and the outer pipe 33.

[0074] In addition, the electromagnetic pump 1 includes a cylindrical housing 70 assembled with an inlet housing ring 50 (which may be referred to as a "converging inlet") configured to deliver fluid 2 into a pumping channel and an outlet housing ring 60 (which may be referred to as a "collector") capable of recovering fluid 2 leaving the pumping channel.

[0075] The internal sensor, internal tube, pumping channel, external tube, external sensor, and housing are arranged substantially concentrically around the central axis X.

[0076] The internal sensor 10 is substantially tubular and includes several comb sections 101, 102, referred to as "internal comb sections", and a plurality of internal coils 111, 112, 113, each internal coil being wound at least between the teeth 101-1, 101-2, 101-3 of each internal comb section 101. The interior 11 of the internal sensor is hollow.

[0077] The external sensor 20 is also basically tubular and includes several comb sections 201, 202, referred to as "external comb sections", and multiple external coils 211, 212, 213, each external coil being wound at least between the teeth 201-1, 201-2, 201-3 of each external comb section.

[0078] The space between the teeth of the inner (or outer) comb can be formed by slots designed to allow the corresponding inner (or outer) coils to pass through.

[0079] Each coil has a loop shape that winds around the central axis and passes between the teeth of the comb.

[0080] According to the present invention, the electromagnetic pump includes a radial movement device 40 that acts on the internal comb portions 101, 102 to adjust the radial gap between the internal sensor 10 and the internal tube 31.

[0081] The described moving device comprises a cam-like mechanism and includes multiple levers 421, 422, wherein the first ends 421A, 422A of the levers extend to the exterior of the electromagnetic pump, allowing control and / or adjustment to be offset and realized from the exterior of the electromagnetic pump. "Outside the electromagnetic pump" means at least outside the active elements (sensors, etc.) of the electromagnetic pump, such as at the pump head. Therefore, adjustment can be achieved by approaching the exterior of the pump, while the stopped pump remains in its proper position within its operating circuit.

[0082] According to the illustrated example, each rod 421 has a threaded first end 421A. More specifically, at its first end, each rod 421, 422 extends through orifices 611, 612 formed in the end plate 610 of the collector 60, and nuts 431, 432 are secured to the threads of the rod 421, 422 exiting the orifices. Therefore, tightening or loosening the nuts on the threads allows adjustment of the rod's movement in the longitudinal direction X of the electromagnetic pump. This tightening / loosening operation can be performed manually or automatically.

[0083] The threaded / nut system is given by way of illustration and is not limiting. As an alternative example to the illustrated screw / nut conversion system, any other system that allows controlled movement of each lever can be envisioned, such as actuators, slide systems, cables, rack / pinion systems, etc. Furthermore, such a system can be placed in locations other than on the collector end plate, or even positioned at other points on the pump.

[0084] The second ends 421B, 422B of each rod are located inside the electromagnetic pump and more specifically within the cavity 11 of the internal sensor 10. A first part 41 for driving a radial movement device is provided between the first and second ends of each rod, particularly a mechanism for driving at least one spring plate 411 in the radial direction.

[0085] Each bar 421 is characterized by having at least one radial recess 421-1 on its lateral surface facing the inner comb section, the recess being associated with a spring plate 411. The middle portion 411C of the spring plate contacts the lateral surface of the bar, and the ends 411A, 411B of the plate also contact the inner comb section 101. Furthermore, the plate is secured to the first comb section by at least one finger 412, such that the plate cannot be driven by the bar to translate in the direction X, and thus acts primarily radially on the inner comb section.

[0086] The plate is therefore advantageously a spring plate. The deformation of the plate effectively ensures the establishment of contact and the application of a contact force that compresses the inner comb and the inner tube against each other. Due to the action of the plate, this contact force remains relatively constant throughout the entire operating range of the electromagnetic pump. Furthermore, the deformation of the plate allows for the absorption of manufacturing and mechanical assembly defects and also absorbs changes in clearance during operation, especially changes in clearance due to dimensional variations caused by temperature levels.

[0087] Alternatively, the sheet may be non-deformable or capable of very small deformation, or it may be replaced by other mechanical components such as, for example, cams.

[0088] According to the depicted embodiment, each bar 421 is associated with an inner comb portion 101, and the recess 421-1 in the bar is associated with a spring plate 411. Therefore, there are as many bars as there are inner comb portions.

[0089] The rod associated with the inner comb section can advantageously be characterized by having a plurality of radial recesses positioned along the longitudinal direction X, each recess being associated with a spring plate. In this case, there are as many spring plates connected to the inner comb section as there are recesses. This means that the pressure applied to the inner comb section can be distributed.

[0090] As rod 421 moves in the longitudinal direction X, spring plate 411 follows the surface of rod. Therefore, when the plate contacts the radial recess 421-1, it drives or retains the inner comb 101 of the electromagnetic pump, thus increasing the gap J1 from the inner tube. Figure 5A Conversely, when the plate contacts the planar surface, it pushes the internal comb towards the internal tube. Figure 5B The gap J2 becomes zero or almost zero. The elasticity of the plate means that it maintains contact with the rod even when it contacts in the radial recess. If the recess is chamfered, such as Figure 4 As shown, an intermediate position can exist, allowing for better adjustment of the positioning of the internal comb relative to the internal tube. More generally, the profile of the recess can be adapted to the actuation mode of the relevant spring sheet and the desired contact control requirements.

[0091] The depicted moving device also includes a support tube 44, above which the rod is positioned. In the depicted device, the rod is uniformly positioned around the entire support tube. The interior of the support tube can be reinforced at at least one recess in the rod, for example, using a reinforcing ring 441 formed against the inner wall of the support tube at the location of the recess. Any other reinforcement means are conceivable.

[0092] The external feature of the support tube may include at least one additional thickness 442 at the location of at least one recess in the rod. This additional thickness forms a local support that compensates for the deflection of the rod that occurs when the rod acts on the plate. Any other means capable of performing this support function can be envisioned, which may incidentally be formed at other locations outside the support tube.

[0093] Furthermore, a rod guide ring 443 is positioned on the outer surface of the support tube. An orifice is formed in the ring to receive and retain the rod while allowing it to slide in the longitudinal direction X. Any other device capable of performing this function of retaining and allowing the rod to slide is conceivable.

[0094] The depicted moving device also includes a radial guide 45 for guiding the inner comb, and it includes, for example, a slide or track connected on one side to the inner comb and on the other side to the end plate 510 of the inlet housing ring.

[0095] The second radial guide device 46 may be disposed at the other end of the inner comb section, and the second radial guide device includes, for example, a slide or track connected on one side to the inner comb section and on the other side to the second plate 520, such as Figure 3B As shown. In this case, preferably, the second plate has orifices 521, 522 for the rods 421, 422 to pass through.

[0096] Any other device capable of performing the function of radial guidance of the internal comb section can be envisioned.

[0097] As depicted, in combination with at least one spring plate, the lever can be dedicated to the radial movement of the inner comb section. Therefore, the radial movement of the inner comb section can be adjusted individually by lever dedicated to it.

[0098] Furthermore, this movable device allows for the inspection (advantageously, separately) of the contact force of the internal comb section without disassembling the electromagnetic pump, and in particular without intruding into the fluid circuit. The contact force can be measured by checking the length of the rod protruding from the electromagnetic pump (beyond adjusting nuts 431, 432). Alternatively, tension on the rod can be measured. For this purpose, a load unit (for measuring compression) can be inserted between nuts 431, 432 and plate 610.

[0099] The ability to measure contact force is particularly advantageous when the fluid is sodium, especially if such measurement does not require disassembly of the electromagnetic pump, such as the electromagnetic pump according to the invention, and is particularly permitted by the contact force measuring device described above.

[0100] The moving device also allows a radial gap to be formed between the inner comb section (the comb section of the internal sensor) and the inner tube, thereby allowing the internal sensor to be introduced into the inner tube. The device can then close the gap again to press the inner comb section against the inner tube. This allows for limiting resistance when inserting the internal sensor into the inner tube outside of operation, and then ensuring heat transfer during operation.

[0101] The heat transfer function permitted by this invention is in Figure 6 The diagram shows an internal comb section 101, an internal coil 111 positioned in a slot between two internal comb sections, an internal tube 31, and a pumping channel 32 in which the pumping fluid 2 circulates. The internal coil 111 carries a current, which is the source of volumetric heat energy. This heat energy is transferred by the coil to the pumping fluid 2, which acts as a cooling fluid. This heat transfer occurs along two paths. The first path is indicated by arrows 64, 61, and 62. Heat energy flows from the coil 111 through the insulator 5 to the comb section 101 (arrow 64), then from the comb section 101 through the gap J to the tube 31 (arrow 61), and then from the tube 31 to the fluid 2 (arrow 62). The second path is indicated by arrows 63, 61, and 62. In this path, heat energy flows from the coil 111 through the insulator 5 (arrow 63) and the gap J (arrow 61 or 65) to the internal tube 31, and then from the internal tube 31 to the fluid 2 through direct contact (arrow 62). Therefore, the gap J directly and significantly relates to two paths for removing the heat generated within the coil 111 to the fluid 2.

[0102] The present invention enables the reduction of the gap J between the insulator 5 of the inner comb 101 and coil 111 and the inner tube 31 on the other hand by pressing the inner comb against the inner tube or at least by bringing them as close as possible. This allows for a significant improvement in heat transfer between the inner comb and the inner tube (arrow 61) and between the coil and the inner tube (arrow 63), thereby improving the removal of heat to the fluid 2 through the inner tube (arrow 62).

[0103] Furthermore, the electromagnetic pump may include a moving device for moving the outer comb section (the comb section of the external sensor), which may be equivalent to, or different from, the moving device for moving the inner comb section as described in the embodiments, within the scope of the claims. This allows heat transfer between the outer comb section and the outer tube to be improved in the same manner as the inner comb section and the inner tube. All variations described with respect to the device for moving the inner comb section are applicable to the device for moving the outer comb section.

[0104] This invention is not limited to the embodiments described above, but extends to any embodiments falling within the scope of the claims.

[0105] This invention can be applied in sodium-cooled fast neutron reactors, particularly in the secondary cooling loop of Na-FNR.

Claims

1. An electromagnetic induction pump (1), which has a basic tubular shape extending in a longitudinal direction (X) and comprises: - A generally tubular internal sensor (10) comprising a plurality of internal combs (101, 102) and a plurality of internal coils (111, 112, 113) disposed at least between the teeth (101-1, 101-2, 101-3) of the internal combs, the internal sensor forming a cavity (11); - An internal tube (31) positioned around the internal sensor (10); - A pumping channel (32) allowing circulation of the fluid (2) to be pumped; - An external tube (33) formed between the internal tube (31) and the external tube (33); - A generally tubular external sensor (20) positioned around the external tube (33) and comprising a plurality of external combs (201, 202) and a plurality of external coils (211, 212, 213) disposed at least between the teeth (201-1, 201-2, 201-3) of the external combs; The electromagnetic induction pump is characterized in that it further includes a moving device (40) for moving the internal comb (101, 102), the moving device being capable of varying the radial gap between the internal comb and the internal tube (31) between a first gap (J1) and a second gap (J2), in the first gap, no teeth in the internal comb contact the internal tube; and in the second gap, all or some of the teeth in the internal comb contact the internal tube, the moving device including a first portion (41) positioned inside the internal sensor and connected to the internal comb to enable radial movement of the internal comb, and a second portion (42) extending at least partially outside the internal sensor and connected to the first portion (41) in a manner that controls the first portion.

2. The electromagnetic induction pump according to claim 1, wherein the second part (42) extends substantially along the longitudinal direction (X) and is movable along the longitudinal direction.

3. The electromagnetic induction pump according to claim 2, wherein the second part (42) comprises a plurality of rods (421, 422), the first ends (421A, 422A) of the plurality of rods extending outside the electromagnetic induction pump (1) and the second ends (421B, 422B) extending into the cavity (11) formed inside the internal sensor (10), each rod being mechanically connected between its first end and its second end to the first part (41) of the moving device located inside the internal sensor.

4. The electromagnetic induction pump according to claim 3, wherein the first end (421A, 422A) of each rod (421, 422) is characterized by having a thread, and the moving device (40) further includes a plurality of nuts (431, 432) that can engage with the thread of the first end of the rod, such that rotation of the nut controls movement of the rod in the longitudinal direction (X).

5. The electromagnetic induction pump according to any one of claims 3 or 4, wherein the first part (41) comprises a plurality of spring plates (411) that are in contact with the inner comb (101) on one side and with the rod (421) on the other side.

6. The electromagnetic induction pump according to any one of claims 3 or 4, wherein each spring plate is fixed to the inner comb section (101).

7. The electromagnetic induction pump according to claim 6, wherein each spring plate is fixed to the inner comb section (101) by a finger (412).

8. The electromagnetic induction pump according to claim 5, wherein each rod (421) is characterized in that it has at least one recess (421-1) on its outer surface that can engage with a spring plate (411) such that when the rod moves along the longitudinal direction (X), the spring plate moves radially between the inside and outside of the recess, or conversely between the outside and inside of the recess, thereby causing radial movement of the inner comb portion (101) in contact with the spring plate.

9. The electromagnetic induction pump according to any one of claims 3 or 4, wherein the rod (421) is capable of controlling the radial movement of a single internal comb (101).

10. The electromagnetic induction pump according to any one of claims 3 or 4, wherein the rod is capable of controlling the radial movement of a plurality of internal comb sections.

11. The electromagnetic induction pump according to any one of claims 3 or 4, wherein the rod is characterized by having a plurality of recesses on its outer surface, the plurality of recesses being capable of engaging with a plurality of spring plates, the plurality of spring plates being in contact with an inner comb portion.

12. The electromagnetic induction pump according to any one of claims 3 or 4, wherein the moving device (40) further comprises a support tube (44), and the rods (421, 422) are positioned above the support tube.

13. The electromagnetic induction pump according to claim 12, wherein the rods (421, 422) are uniformly positioned around the support tube (44).

14. The electromagnetic induction pump according to claim 12, wherein the support tube (44) includes at least one reinforcing ring (441), the reinforcing ring being positioned against the inner wall of the support tube at the location of the recess (421-1, 422-1) of the rod (421, 422).

15. The electromagnetic induction pump according to claim 12, wherein the support tube (44) is characterized in that it has an additional thickness (442) on its outer wall at the location of the recess (421-1, 422-1) of the rod (421, 422).

16. The electromagnetic induction pump according to claim 12, wherein the support tube (44) includes a guide ring (443) on its outer wall for guiding the rod (421, 422), the guide ring including an orifice allowing the rod to move along the longitudinal direction (X).

17. The electromagnetic induction pump according to any one of claims 1 to 4, wherein the moving device (40) further comprises a radial guide device (45) for guiding the internal comb (101, 102).

18. The electromagnetic induction pump according to any one of claims 1 to 4 further includes a radial moving device for moving the outer comb (201, 202) of the outer sensor (20), the moving device being capable of changing the radial gap between the outer comb and the outer tube (33).

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