Device for measuring a liquid level in a tank and associated method of use

Abstract

A measuring device (1) for measuring a liquid level (K) in a tank (R), the measuring device (1) comprising a guide conduit (2); a plurality of magnetic switches (4A-4D) each configured to move between an open state (E1) and a closed state (E0); a float (3) mounted for translational movement within the guide conduit (2), the float (3) comprising a main body (6) and at least one magnetic element (5), configured to change the state of a magnetic switch (4A-4D) so as to determine the liquid level (K), the main body (6) extending longitudinally along a body axis (X6) oriented from bottom to top between a lower end and an upper end, the main body (6) having a body height defined along the body axis (X6) from the lower end, the magnetic element (5) being positioned in an upper half of the main body (6). (Shortcut Figure: Figure 5)

Description

Title of the invention: Device for measuring a liquid level in a tank and associated method of use. Technical field

[0001] The present invention relates to the field of measuring a liquid level in a tank. The invention is particularly relevant to devices for measuring the level of a liquid that may become contaminated during its use.

[0002] It is known to measure the level of a liquid in a tank, for example an aircraft tank, by means of a measuring device with magnetic switches. With reference to [Fig. 1], such a measuring device 100 is mounted directly inside a tank R to measure the level of a liquid K in the tank R.

[0003] For this purpose, the measuring device 100 includes a guide conduit 200 mounted in the reservoir R and immersed in the liquid K. The guide conduit 200 extends longitudinally along an axis X, extending substantially vertically in the reservoir R, and includes a float 300 mounted movable in translation in the guide conduit 200.

[0004] The measuring device 100, shown in more detail in [Fig. 2], also includes a plurality of magnetic switches 400 distributed along the longitudinal axis X along the length of the guide conduit 200. Each magnetic switch 400 moves between an open state (shown in white) and a closed state (shown in black) and is connected to a network of resistors Q. The configuration of the set of closed and open magnetic switches 400 makes it possible to determine a characteristic electrical resistance value of a liquid level K.

[0005] To determine the liquid level K in the reservoir R, the float 300 includes a magnetic element 500, which changes the state of a magnetic switch 400, for example from an open state to a closed state, when positioned opposite the latter. For this purpose, as shown in [Fig. 3], the magnetic element 5 emits a magnetic field CM which interacts with the magnetic switch 400 positioned opposite it, placing it, for example, in the closed state. In practice, as the liquid level K decreases, the float 300 slides along the longitudinal axis X, descends in the guide channel 200, and successively changes the state of the magnetic switches 400 as it passes in front of each one.

[0006] However, when the measuring device 100 is mounted in a polluted environment, such as an engine lubrication oil reservoir, PAR magnetic particles are present in the liquid K. As shown in [Fig. 4], the PAR magnetic particles are attracted to the organ The magnetic element 500 forms a magnetic barrier between the magnetic element 500 and the magnetic switches 400. The magnetic field CM emitted by the magnetic element 500 is therefore not detected by the magnetic switches 400, whose state remains unchanged. The level of the liquid K cannot be determined.

[0007] Therefore, it is necessary to clean the measuring device 100 to remove PAR magnetic particles and ensure its optimal operation. For this purpose, maintenance operations must be performed regularly to remove the PAR magnetic particles that have accumulated on the magnetic element 500. Such repeated maintenance operations are time-consuming and result in the immobilization of the system in which the liquid reservoir is mounted, which is a significant drawback. When the reservoir is mounted, for example, in an aircraft, the maintenance operation required to clean the liquid level detection device necessitates the complete immobilization of the aircraft and the removal and repositioning of the measuring device in the reservoir, which significantly increases maintenance time and costs.

[0008] The invention thus aims to eliminate at least some of these drawbacks by providing a simple, reliable device for measuring the liquid level in a tank, which also reduces maintenance requirements. The measuring device according to the invention is specifically designed to ensure that a magnetic switch detects the magnetic field emitted by the magnetic element, even when the measuring device is mounted in a polluted environment. PRESENTATION OF THE INVENTION

[0009] The invention relates to a liquid level measuring device configured to be mounted in a tank, the measuring device comprising: • a guide conduit extending along a conduit axis, • a plurality of magnetic switches distributed at different longitudinal positions along the duct axis, each magnetic switch being configured to alternate between an open and a closed state, • a float mounted to move in translation within the guide duct along the duct axis, • the float comprising a main body and at least one magnetic element, mounted in said main body, configured to modify the state of a magnetic switch when said magnetic element is located opposite the magnetic switch, so as to determine the liquid level, • the main body extending longitudinally along a body axis oriented from bottom to top between a lower end and an upper end, the main body having a body height defined along the body axis at Starting from the lower end, the magnetic organ is positioned in an upper half of the main body.

[0010] The magnetic element positioned in the upper half of the main body allows the center of gravity of the float to be changed, causing it to be inclined and thus in contact with the inner walls of the guide tube in which it is mounted. Therefore, when the liquid is contaminated and contains magnetic particles that accumulate on the float, attracted by the magnetic element, the contact between the float and the guide tube causes the magnetic particles to rub off, detach from the float, and fall away.

[0011] Similarly, when the measuring device is subjected to vibrations, for example in an aircraft, the center of gravity of the off-center float causes a pendulum effect that allows the float to collide with the guide duct. When magnetic particles are agglomerated on the float, the impacts against the walls of the guide duct advantageously dislodge them.

[0012] In other words, the measuring device according to the invention makes it possible to automatically clean the float of polluting magnetic particles, which significantly reduces maintenance operations and helps to limit costs and delays.

[0013] In a preferred embodiment, the body axis forms an angle with the conduit axis strictly greater than 0°, which ensures an inclined position of the float in the guide conduit and therefore friction of the main body of the float against the inner walls of the guide conduit.

[0014] Preferably, the magnetic element is positioned at a defined height along the body axis, satisfying the following condition: H5 / H6 > 75%. Thus, the magnetic element is positioned sufficiently close to the upper end of the main body to ensure that, in the event of magnetic particle agglomeration, these particles are located in an area of ​​the float in contact with the guide duct. This ensures that the magnetic particles are effectively rubbed together during contact between the float and the walls of the guide duct.

[0015] Preferably, the magnetic element is positioned substantially at the upper end of the main body, allowing optimal positioning to ensure that all conductive particles are removed by friction against the guide conduit.

[0016] In one embodiment, • the guide duct having a flat interface wall and extending longitudinally along the duct axis and laterally along a lateral axis orthogonal to the duct axis so as to define an interface plane, • the float comprising a main body including a measuring wall opposite the interface wall of the guide duct, the measuring wall being flat and extending longitudinally along the body axis and laterally along a lateral axis orthogonal to the body axis so as to define a measuring plane, the main body having a depth defined along an axis orthogonal to the measuring plane and oriented from a rear to a front, the measuring wall forming a front wall, • The magnetic organ is positioned in a front portion of the main body.

[0017] Such an embodiment allows the magnetic element to be mounted asymmetrically in the main body, in a plane transverse to the body axis, which makes it possible to ensure that the upper half is properly inclined even in the absence of rocking or unbalanced movement, thus ensuring the friction of the float against the walls of the guide conduit.

[0018] According to a preferred aspect, the guide duct has a cross-section corresponding to a half-disk, which ensures optimal guidance of the float in the guide duct.

[0019] Preferably, the guide duct includes an interface wall comprising an inner face facing the float and an outer face. The magnetic switches are mounted on the outer face of the interface wall. The magnetic switches are thus mounted externally to the guide duct, as close as possible to the magnetic element.

[0020] In one embodiment, the guide duct comprises at least one guide rail extending longitudinally along the duct axis. The guide rail is configured to contact the float within a defined friction zone on the float. The magnetic element is mounted in this friction zone. This positioning ensures that, in the presence of magnetic particles, they are effectively agglomerated in the friction zone, thereby allowing the float to be efficiently cleaned by friction against the guide rail. Furthermore, the guide rail effectively guides the float, preventing continuous friction across the entire interface wall.

[0021] Preferably, the guide duct comprising an interface wall having an inner face facing the float and an outer face, the guide duct includes at least two guide rails extending longitudinally along the duct axis and mounted on the inner face of the interface wall. Two guide rails allow for both optimal guidance and increased friction surface area to enable improved removal of all conductive particles.

[0022] In one embodiment: • the interface wall being flat and extending longitudinally along the duct axis and laterally along a lateral axis orthogonal to the duct axis so as to define an interface plane, • the float comprising a main body including a measuring wall opposite the interface wall of the guide duct, the measuring wall being flat and extending longitudinally along the body axis and laterally along a lateral axis orthogonal to the body axis so as to define a measuring plane, • the magnetic element having a width defined along the lateral axis of the main body, • the two guide rails, mounted on the inner face of the interface wall, are spaced along the lateral axis of the guide conduit, with a spacing distance less than the width of the magnetic element.

[0023] A spacing distance between the two guide rails less than the width of the magnetic element ensures that the two guide rails are mounted in an area where the magnetic field, looping back with the magnetic switch, is emitted by the float, ensuring optimal friction of the float.

[0024] The invention also relates to an assembly of a reservoir comprising a liquid and a device for measuring the level of liquid in the reservoir as described above, the measuring device being mounted in the reservoir.

[0025] The invention also relates to an aircraft comprising at least one liquid tank and a device for measuring the liquid level in the tank as described above.

[0026] Furthermore, the invention relates to a method of using a measuring device as described above, each magnetic switch being initially in the closed state or in the closed state and having a longitudinal position, the method comprises the steps of: • modify the state of one of the magnetic switches when the magnetic element is located opposite said magnetic switch during the movement of the float along the guide duct along the duct axis, and • measure the liquid level in the guide tube from the states of the magnetic switches, the float being cleaned of potential magnetic polluting particles by friction against the guide tube during its movement.

[0027] The invention also relates to a liquid level measuring device configured to be mounted in a tank, the measuring device comprising: • a guide duct extending along a duct axis, the guide duct comprising a plurality of magnetic switches distributed at different longitudinal positions along the duct axis, each magnetic switch being configured to move between an open state and a closed state, • a float mounted to move in translation within the guide duct along the duct axis, • the float comprising a main body and at least one magnetic element, mounted in said main body, configured to modify the state of a magnetic switch when said magnetic element is located in the longitudinal position of the magnetic switch, so as to determine the liquid level, • the guide conduit comprising at least one guide rail extending longitudinally along the conduit axis, the guide rail being configured to come into contact with the float according to a defined friction zone on the float, the magnetic element is mounted in the friction zone.

[0028] A magnetic element mounted in the friction zone attracts any magnetic particles in this friction zone in contact with the guide rails, thereby automatically removing the magnetic particles by friction between the float and the guide duct. This "automatic" removal allows the measuring device to self-clean of such magnetic particles, thus reducing the maintenance required for such a measuring device. PRESENTATION OF FIGURES

[0029] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0030] Fig. 1 is a schematic representation of a tank in which a measuring device according to the prior art is mounted.

[0031] Fig. 2 is a close-up view of the measuring device of Fig. 1.

[0032] Figure 3 is a cross-sectional view of a guide duct and a float opposite each other. of a magnetic switch of the measuring device of the [Fig.2].

[0033] Fig. 4 is a cross-sectional view of the guide duct and float of Fig. 3 opposite a magnetic switch of the measuring device of the [Fig.2] in the presence of magnetic particles.

[0034] Fig. 5 is a schematic representation of a tank in which a measuring device is mounted according to one embodiment of the invention.

[0035] Fig. 6 is a close-up view of a guide duct and a float of the guide device of Fig. 5.

[0036] Fig. 7 is a cross-sectional view of the guide conduit of the measuring device of Fig. 5 comprising guide rails.

[0037] Fig. 8 is a schematic representation of a float and a magnetic element of the measuring device of Fig. 5.

[0038] Fig. 9 is a schematic representation of the positioning of the float and the magnetic element in a guide conduit of the measuring device of Fig. 5.

[0039] It should be noted that the figures set out the invention in detail to implement the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0040] The invention relates to a device for measuring the level of a liquid in a tank. The invention will be described for measuring the level of a liquid stored in an aircraft tank. However, it is understood that the invention applies to any type of liquid stored in any type of tank.

[0041] It is represented in [Fig.5], a reservoir R comprising a liquid K and a measuring device 1 of a level of the liquid K in the reservoir R, according to one embodiment of the invention.

[0042] With reference to [Fig.5], the measuring device 1 comprises a guide conduit 2, a plurality of magnetic switches 4A-4D distributed along the guide conduit 4, and a float 3, comprising a magnetic element 6, mounted in the guide conduit 2.

[0043] The guide conduit 2 extends longitudinally along a conduit axis X2 and is configured to extend into the tank R, so as to measure different levels of liquid K. The conduit axis X2 extends along the axis of gravity under nominal operating conditions.

[0044] The guide conduit 2 is open or porous, so as to allow the liquid K to penetrate inside.

[0045] With reference to Figures 6 and 7, the guide duct 2 preferably comprises a flat interface wall 7 extending longitudinally along the duct axis X2. The interface wall 7 also extends laterally along an axis Y2, which forms an interface plane (X2, Y2) with the duct axis X2. An axis Z2 is also defined, extending orthogonally to the interface wall 7, i.e., orthogonally to the interface plane (X2, Y2). In practice, the axis Z2 extends into the depth of the duct. guidance 2, from a rear to a front, towards the interface wall 7, also called the "front wall", as shown in figures 6 and 7.

[0046] According to one aspect, the interface wall 7 comprises an inner face 71 extending inside the guide conduit 2 and an outer face 7E extending outside the guide conduit 2. In this example, the interface wall 7 has a height H7 defined along the conduit axis X2 and a width D7 defined along the lateral axis Y2, shown in Figures 6 and 7. The interface wall 7 preferably has a shape complementary to a wall of the float 3 comprising the magnetic element 6, which will be described in more detail later.

[0047] In this example, the guide duct 2 has the shape of a hollow half-cylinder and, as such, includes a so-called "back" wall 20 having a curved shape and extending into the depth of the guide duct 2, as shown in [Fig. 6]. In other words, the guide duct 2 has a cross-section, in a transverse plane (Y2, Z2), corresponding to a half-disk. It is understood that the back wall 20 could alternatively have a different shape. In particular, it is understood that the guide duct 2 could have a different shape, for example, a rectangular parallelepiped shape. Preferably, the back wall 20 has a shape complementary to a wall of the float 3 lacking a magnetic element 6. The back wall 20 facilitates the guidance of the float 3, as will be shown later.

[0048] According to a preferred aspect, with reference to [Fig. 7], the guide duct 2 comprises a plurality of guide rails 8, configured to guide the float 3 in the guide duct 2. Each guide rail 8 extends longitudinally along the duct axis X2. The guide rails 8 are mounted on the interface wall 7 and the rear wall 20 so as to form discrete contact areas with the float 3 to allow wear-free guidance.

[0049] More specifically, in this example, the guide duct 2 comprises five guide rails 8, distributed around the inner circumference of the guide duct 2. In particular, in this example, the guide duct 2 includes two guide rails 8 mounted on the inner face 71 of the interface wall 7 and three guide rails 8 distributed on the rear wall 20. The guide rails 8 mounted on the inner face 71 are configured to contact the float 3, as will be described in more detail later. It is understood that the number of guide rails 8 could be different. Preferably, the number of guide rails 8 mounted on the inner face 71 of the interface wall 7 is two or more.

[0050] As described previously, with reference to [Fig. 5], the measuring device 1 comprises a plurality of magnetic switches 4A-4D distributed along the guide conduit 2. For clarity in the figures, only four magnetic switches 4A-4D are shown in the figures; however, it is understood that their number could be different. More precisely, the magnetic switches 4A-4D are distributed at different longitudinal positions PA-PD along the duct axis X2. Preferably, as shown in Figures 5 and 7, the magnetic switches 4A-4D are mounted on the outer face 7E of the interface wall 7. Even more preferably, each magnetic switch 4A-4D is mounted centrally with respect to the lateral axis Y2 of the guide duct 2.

[0051] Each magnetic switch 4A-4D is configured to operate between an open state El and a closed state E0. In practice, each magnetic switch 4A-4D is connected to a network of resistors Q, which is connected to a computer 9 via an electrical network Elec. The configuration of all the magnetic switches 4A-4D in the closed state E0 and those in the open state El determines a characteristic electrical resistance value K for a liquid level.

[0052] For this purpose, in this example, the calculator 9 includes a database and is configured to receive the states E0 / E1 of each magnetic switch 4 and to determine a liquid level K from the closed states E0 or open states El of the set of magnetic switches 4A-4D.

[0053] To evolve between the open state El and the closed state E0, each magnetic switch 4A-4D is configured to interact with a float 3 mounted in the guide conduit 2.

[0054] Still referring to [Fig.5], the float 3 is mounted to move in translation within the guide conduit 2. The float 3 moves with the liquid level K in the reservoir R. In other words, the float 3 is configured to move between different longitudinal positions along the conduit axis X2.

[0055] For this purpose, the float 3 comprises a main body 6, made of a material having a density lower than that of the liquid K in which it is immersed, and a magnetic element 5.

[0056] With reference to [Fig.8], the main body 6 extends longitudinally along a body axis X6, oriented from bottom to top between a lower end 6a and an upper end 6b.

[0057] The main body 6 preferably comprises a flat "measuring" wall 60 configured to be mounted opposite the interface wall 7 of the guide conduit 2. In this example, the measuring wall 60 extends longitudinally along the body axis X6 and laterally along an axis Y6, which forms a measuring plane (X6, Y6) with the body axis X6. An axis Z6 is also defined, extending orthogonally to the measuring wall 60, that is, orthogonally to the measuring plane (X6, Y6). In practice, again with reference to Figures 6 and 7, the axis Z6 extends through the depth of the main body 6, from a rear to a front, towards the measuring wall 60. Preferably, the lateral axis Y6 of the main body 6 is collinear with the lateral axis Y2 of the guide conduit 2.

[0058] According to a preferred embodiment, the main body 6 has a shape complementary to that of the guide conduit 2, so that it can slide along the conduit axis X2 while being guided. In this respect, the main body 6, in this example, has the shape of a half-cylinder and includes a so-called "back" wall 30 which has a curved shape and extends into the depth of the main body 6, as shown in [Fig. 6]. In other words, the main body 6 has a cross-section, in a transverse plane (Y6, Z6), corresponding to a half-disk. It is understood that the back wall 30 of the main body 6 could alternatively have a different shape. In particular, it is understood that the main body 6 could have a different shape, for example, a rectangular parallelepiped shape. Preferably, the back wall 30 of the main body 6 has a shape complementary to the back wall 20 of the guide conduit 2.Thanks to the rear wall 30, the float 3 is advantageously guided in the guide duct 2, as will be shown later.

[0059] In this example, as shown in [Fig. 8], the main body 6 has a body height H6 defined along the body axis X6 from the lower end 6a. The body height H6 along the body axis X6 is divided, in this example, into a lower half 61 and an upper half 62. Similarly, the main body 6 has a body width D6, defined along the lateral axis Y6 and shown in [Fig. 7]. The body width D6 corresponds to the width of the measuring wall 60 of the main body 6. Furthermore, the main body 6 has a body depth B6, shown in Figures 7 and 8, defined along the axis Z6. In this example, the body depth B6 is divided equally into a front portion 63 (corresponding to the portion opposite the interface wall 7 of the guide conduit 2, in other words the front portion 63 includes the measuring wall 60) and a rear portion 64.

[0060] As described previously, to modify the state E0 / E1 of the magnetic switches 4A-4D distributed along the guideway 2, the measuring device 1 includes a magnetic element 5, mounted in the main body 6 of the float 3. A single magnetic element 5 is described in this document, however it is understood that the measuring device 1 could include more than one magnetic element 5.

[0061] According to one aspect of the invention, the magnetic member 5 is configured to change the state of a magnetic switch 4A-4D when it is located opposite the magnetic switch 4A-4D.

[0062] The magnetic element 5 is presented for example in the form of a magnet having any shape whatsoever, in particular, parallelepiped, cylindrical or spherical.

[0063] The position of the magnetic element 5 in the main body 6 is subsequently defined with reference to the body axis X6 and the transverse cutting plane (Y6, Z6) of the main body 6.

[0064] With further reference to [Fig. 8], the magnetic element 5 is positioned, according to one aspect of the invention, in the upper half 62 of the main body 6. Such positioning allows the float 3, when mounted in the guide duct 2, to be inclined, creating an imbalance around the first measuring axis Y6, shown in [Fig. 9]. The inclination of the float 3 results in preferential contact between the main body 6 and the guide duct 2, and more specifically between the main body 6 and the guide rails 8 mounted on the inner face 71 of the interface wall 7 of the guide duct 2.The contact allows, when magnetic particles are present in the liquid K for example and these are attracted by the magnetic element 5, the float 3 to be rubbed against the interface wall 7 and in particular against the guide rails 8, thus allowing the magnetic particles to be removed and the measuring device 1 to be cleaned, as will be described in more detail later.

[0065] More specifically, the magnetic element 5 is preferably positioned in the main body 6 at an element height H5, shown in [Fig. 8] and determined along the body axis X6 from the lower end 6a of the main body 6, satisfying the following condition: H5 / H6 > 75%. In other words, the element height H5 preferably corresponds to 75% of the body height H6. Preferably, the magnetic element 5 is positioned in the upper half 62 of the main body 6, substantially close to the upper end 6b, to ensure that, in the event of an agglomeration of conductive PAR particles, these particles are located substantially in an area of ​​the float 3 in contact with the inner face 71 of the interface wall 7, so as to be optimally removed, as will be described in more detail later. This also allows for an increase in the inclination of the float 3 around the lateral axis Y6.

[0066] With reference to [Fig. 7], the magnetic element 5 is preferably positioned along the lateral axis Y6 of the main body 6, in a centered manner. This lateral position allows it to be positioned opposite the magnetic switches 4A-4D, which are then able to capture the magnetic field emitted by the magnetic element 5 to change their state E0 / E1.

[0067] Furthermore, as shown in [Fig. 8], in a preferred embodiment, the magnetic element 5 is preferably positioned within the depth of the main body 6, that is, along the axis Z6, in the forward portion 63. Such positioning increases the weight of the float 3 against the interface wall 7, thereby increasing friction and enabling more effective cleaning. An assembly The placement of the magnetic element 5 in the front portion 63 also allows the use of a magnetic element 5 with smaller dimensions and mass. It goes without saying that the magnetic element 5 could alternatively be centered within the depth of the main body 6, i.e., along the Z6 axis.

[0068] Due to the positioning of the magnetic element 5 within the main body 6, the float 3 has a center of gravity that does not lie on the body axis X6 along which it extends. As a result, the float 3 is unbalanced and tilts during use. Because of this imbalance, the float 3 has a preferred friction zone ZF, shown in [Fig. 8], configured to contact the interface wall 7 and, more specifically, the guide rails 8, as will be described in more detail later. The preferred friction zone ZF is preferably positioned on the upper half 62 of the flat wall 60 of the main body 6, and even more preferably, near the upper end 6b. This is contrary to the general practice of those skilled in the art, which aims to keep the float 3 aligned with the guide duct 2 to reduce friction.Thanks to the invention, the inevitable friction fulfills a cleaning function.

[0069] Due to the imbalance, the body axis X6 preferably forms an angle α strictly greater than 0° with the conduit axis X2. In this example, the angle α is between 5 and 15°.

[0070] In a preferred embodiment, the magnetic element 5 is mounted in the preferred friction zone ZF of the float 3, as shown in [Fig. 9]. Thus, when magnetic PAR particles are present in the liquid K, for example, these are attracted by the magnetic element 5 in the friction zone ZF, which makes it possible to rub the float 3 against the interface wall 7 and in particular against the guide rails 8, thereby removing the magnetic PAR particles and automatically cleaning the measuring device 1, as will be described in more detail later.

[0071] A method of using the measuring device 1 as described above will be described with reference to [Fig. 9]. The measuring device 1 is mounted in a tank R containing a liquid K whose level is to be measured. The float 3 is initially positioned in the guide tube 2 inclined about the lateral axis Y6, i.e., inclined along the depth of the guide tube 2. The float 3 is shaped so as to be unbalanced during its floatation. The float 3 is inclined so that the upper end 6b of the main body 6 is inclined forward. In other words, the flat wall 60 of the main body 6 of the float 3 is initially in contact, in this example with the guide rails 8 mounted on the inner face 71 of the interface wall 7. In this example, each magnetic switch 4A-4D is initially in the closed state E0 and is mounted on the outer face 7E of the interface wall 7 at a predetermined longitudinal position PA-PD. In this example, the liquid K is contaminated and contains magnetic particles PAR.

[0072] In a preliminary step FO, the magnetic particles PAR are attracted by the magnetic field emitted by the magnetic element 5 mounted in the float 3. These then agglomerate on the flat wall 60 of the main body 6 opposite the magnetic element 5.

[0073] The method includes a first step Fl of moving the float 3 inside the guide conduit 2 along the conduit axis X2. In practice, in this example, the liquid level K drops in the reservoir R. The float 3 then descends in the guide conduit 2 and its longitudinal position is modified along the conduit axis X2.

[0074] With the float 3 inclined forward in the guide duct 2, in this step Fl, as it moves along the duct axis X2, the main body 6 of the float 3 rubs against the inner face 71 of the interface wall 7 of the guide duct 2. In practice, in this example, the upper half 62 of the main body 6, in which the magnetic element 5 is mounted, rubs against the guide rails 8 mounted on the inner face 71 of the interface wall 7. Such friction causes the flat wall 60 of the main body 6 to be scraped, resulting in the removal of the PAR magnetic particles agglomerated on the float 3 at the level of the magnetic element 5. Thanks to the position of the magnetic element 5 in the main body 6, the float 3 is automatically cleaned of the polluting PAR magnetic particles present in the liquid K during its movement.

[0075] In a second step F2, when the float 3 is opposite one of the magnetic switches 4, the latter changes from the closed state E0 to the open state EL. In practice, the float 3, advantageously cleaned of any magnetic particles PAR, ensures that the magnetic switch 4 detects the magnetic field CM emitted by the magnetic element 5, allowing its change of state.

[0076] In this example, an electrical resistance characteristic of the states E0 / E1 of the magnetic switches 4A-4D (only a part of which is shown in [Fig.9]) is sent, in a step F3, to a computer 9 which determines, from the value of electrical resistance received, the level of liquid K in the reservoir R.

[0077] In practice, for mounting in an aircraft, the latter emits vibrations in flight which cause the float 3 to move in the guide duct 2. The float 3 comes into contact with the interface wall 7. The impacts of the flat wall 60 of the main body 6 against the interface wall 7 of the guide duct 2 also advantageously allow the float 3 to be freed from the magnetic PAR particles which could have agglomerated by causing them to fall.

[0078] The measuring device 1 according to the invention makes it possible to ensure the reliability of the measurement of the liquid level K, even in a polluted environment, by ensuring that the float 3 is always clean and free of polluting particles.

Claims

Demands

1. A measuring device (1) for a liquid level (K) configured to be mounted in a tank (R), the measuring device (1) comprising: • a guide conduit (2) extending along a conduit axis (X2), • a plurality of magnetic switches (4A-4D) distributed at different longitudinal positions along the conduit axis (X2), each magnetic switch (4A-4D) being configured to move between an open state (El) and a closed state (EO), • a float (3) mounted to move in translation within the guide conduit (2) along the conduit axis (X2), • the float (3) comprising a main body (6) and at least one magnetic element (5), mounted in said main body (6), configured to change the state of a magnetic switch (4A-4D) when said magnetic element (5) is located opposite the magnetic switch (4A-4D), so as to determine the liquid level (K),• the main body (6) extending longitudinally along a body axis (X6) oriented from bottom to top between a lower end (6a) and an upper end (6b), the main body (6) having a body height (H6) defined along the body axis (X6) from the lower end (6a), the magnetic element (5) is positioned in an upper half (62) of the main body (6), the magnetic element (5) being positioned at an element height (H5) defined along the body axis (X6) satisfying the following condition H5 / H6 >75%.

2. Measuring device (1) according to claim 1, wherein: • the guide duct (2) having a flat interface wall (7) extending longitudinally along the duct axis (X2) and laterally along a lateral axis (Y2) orthogonal to the duct axis (X2) so as to define an interface plane (X2, Y2), • the float (3) comprising a main body (6) including a measuring wall (60) opposite the interface wall (7) of the guide duct (2), the measuring wall (60) being flat and extending longitudinally along the body axis (X6) and laterally along a lateral axis (Y6) orthogonal to the body axis (X6) so as to define a measuring plane (X6, Y6), the main body (6) having a depth (B6) defined along an axis (Z6) orthogonal to the measuring plane (X6, Y6) and oriented from rear to front, the measuring wall (60) forming a wall before, • the magnetic organ (5) is positioned in a front portion (63) of the main body (6).

3. Measuring device (1) according to any one of claims 1 to 2, wherein the guide conduit (2) comprising an interface wall (7) comprising an inner face (71) facing the float (3) and an outer face (7E), the magnetic switches (4A-4D) are mounted on the outer face (7E) of the interface wall (7).

4. Measuring device (1) according to any one of claims 1 to 3, wherein the guide conduit (2) comprising at least one guide rail (8) extending longitudinally along the conduit axis (X2), the guide rail (8) being configured to come into contact with the float (3) according to a friction zone (ZF) defined on the float (3), the magnetic element (5) is mounted in the friction zone (ZF).

5. Measuring device (1) according to claim 4, wherein the guide conduit (2) includes an interface wall (7) comprising an inner face (71) facing the float (3) and an outer face (7E), the guide conduit (2) includes at least two guide rails (8) extending longitudinally along the conduit axis (X2) and mounted on the inner face (71) of the interface wall (7).

6. Measuring device (1) according to claim 5, wherein: • the interface wall (7) is flat and extends longitudinally along the conduit axis (X2) and laterally along a lateral axis (Y2) orthogonal to the conduit axis (X2) so as to define an interface plane (X2, Y2), • the float (3) has a main body (6) comprising a measuring wall (60) opposite the interface wall (7) of the guide conduit (2), the measuring wall (60) is flat and extends longitudinally along the body axis (X6) and laterally along a lateral axis (Y6) orthogonal to the body axis (X6) so as to define a measuring plane (X6, Y6), • the magnetic element (5) has a width (D5) defined along the lateral axis (Y6) of the main body (6), • the two guide rails (8), mounted on the inner face (71) of the interface wall, (7) are spaced along the lateral axis (Y2) of the guide conduit (2),with a spacing distance (D8) less than the width (D5) of the magnetic element (5).

7. Assembly of a reservoir (R) comprising a liquid (K) and a measuring device (1) for the level of liquid (K) in the reservoir (R) according to any one of claims 1 to 6, the measuring device (1) being mounted in the reservoir (R).

8. Aircraft comprising at least one liquid (K) reservoir (R) and a device for measuring the liquid (K) level in the reservoir (R) according to any one of claims 1 to 6.

9. A method of using a measuring device (1) according to any one of claims 1 to 6, each magnetic switch (4A-4D) being initially in the closed state (E0) or in the closed state (El) and having a longitudinal position (PA-PD), the method comprises the steps of: modify the state (E0 / E1) of one of the magnetic switches (4A-4D) when the magnetic member (5) is located opposite said magnetic switch (4A-4D) during the movement of the float (3) along the guide conduit (2) along the conduit axis (X2), and measure the liquid level (K) in the guide conduit (2) from the states (E0 / E1) of the magnetic switches (4A-4D), the float (3) being cleaned of potential polluting magnetic particles (PAR) by friction against the guide conduit (2) during its movement.

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