The present invention relates to a filter for a rail vehicle sandbox, an associated rail vehicle and a corresponding method for providing a filter.
The sandbox is capable of increasing the adhesion between the wheel and the rail of a rail vehicle by adding sand between the wheel and the rail. This is particularly advantageous for starting the vehicle, for example, especially on a steep slope or climb, or on a slippery rail, or to assist in an emergency stop.
However, waste such as cigarette butts or wrappings may be present in the sandbox, which could prevent the sandbox from functioning properly by clogging the sand ejectors at the outlet of the reservoir of the sandbox.
The invention has the purpose of providing a system for preventing the sandbox from clogging at the ejectors.
To this end, the invention has a filter of the aforementioned type as its object, comprising a strainer adapted to be placed at the inlet of a rail vehicle sandbox, the strainer comprising a tube, the strainer comprising at least one filtering area provided with at least one sieve.
This filter makes it possible to retain any undesired object at the sandbox inlet so as to prevent said object from clogging the sandbox at the ejectors.
Furthermore, this filter is advantageously capable of being installed on vehicles with existing sandboxes, with the filter intended to be placed directly at the inlet of the vehicle sandbox.
The filter may further have one or more of the following features, considered individually or in any technically possible combination:
- the at least one filtering area only extends over one portion of the strainer;
- the strainer comprises a bottom, the tube extending between a free end and an attached end, the attached end being intended to be connected to the sandbox inlet, the bottom being attached to the free end of the tube and closing the tube at the free end;
- the at least one filtering area extends only over a portion of the tube and/or a portion of the bottom;
- the filter comprises a spacer, with the tube having an attached end for connection to the inlet of the sandbox, the strainer comprising a shoulder extending from the attached end of the tube, the spacer being provided to extend between the shoulder and the sandbox inlet;
- the strainer is screwed to the spacer;

- the sieve has through holes, each through hole having an area of between 10 mm2 and 20 mm2,
- the at least one filter area comprises a first filtration sub-area arranged on a portion of the tube and a second filtration sub-area arranged at the bottom, with each filtration sub-area provided with a respective sieve, and/or
- the tube is cylindrical.
The invention further relates to a rail vehicle comprising a sandbox having an inlet and a filter of the aforementioned type, with the filter attached to the sandbox inlet.
The invention further relates to a method for placing a filter at an inlet of a rail vehicle sandbox comprising the following steps:
- providing a filter of the above type, and
- attaching the filter strainer to a wall of the vehicle surrounding the sandbox inlet, the tube extending from the sandbox inlet to the sandbox reservoir.
Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, given by way of example only and with reference to the drawings in which:
[Fig 1] Figure 1 is a schematic cross-sectional view of a sandbox provided with a filter according to one embodiment of the invention, and
[Fig. 2] Figure 2 is an exploded view of the filter of Figure 1.
The invention relates to a filter 10 for a sandbox 12 of a rail vehicle 14.
The sandbox 12 comprises a reservoir 16, for example.
The sandbox has an inlet 18 and an outlet (not visible), and comprises an ejector or ejectors at the reservoir outlet. The ejector(s) are provided to eject sand from the reservoir between a wheel of the rail vehicle 14 and the rail.
The inlet 18 is located above the reservoir in a vertical direction Z corresponding to the perpendicular of the rolling plane of the vehicle.
The inlet 18 of the sandbox 12 has the shape of a disk cutout in a wall of the vehicle, for example.
Between the inlet 18 and the reservoir 16, the sandbox 12 has an insertion duct connecting the inlet 18 and the reservoir 16.
The insertion duct is straight, more particularly cylindrical.
The filter 10 according to the invention comprises a strainer 20.
The filter 10 further comprises a spacer 22, in the example shown.
The filter 10 further comprises a cover 24, in the example shown.
The strainer 20 is adapted to be placed at the inlet 18 of the sandbox 12.

The strainer 20 is provided for filtering material injected into the reservoir 16 through the inlet 18, more particularly to filter out any foreign matter such as leaves or trash from the sand.
More particularly, the strainer 20 is provided to be attached to the inlet 18 of the sandbox 12.
Here, the strainer 20 is provided for extending from the inlet 18 into the interior of the sandbox towards the reservoir, more particularly into the reservoir 16, more particularly here through the insertion duct and partially into the reservoir 16.
In particular, the strainer 20 has dimensions suitable for extending from the inlet 18 into the interior of the sandbox towards the reservoir 16.
The strainer 20 here is made of metal.
The strainer 20 comprises a tube 26. The tube 26 here is cylindrical.
The strainer 20 further comprises a bottom 27.
The tube 26 extends around a cylinder axis D.
In a variant, the tube 26 is non-cylindrical and extends about a central axis, with a section of the tube 26 perpendicular to the central axis having the shape of an ellipse or polygon.
The tube 26 extends between a free end 28 and an attached end 30, specifically along the cylinder axis D.
The tube 26 here is truncated along a plane perpendicular to the cylinder axis D at the free end 28.
The tube 26 here is truncated along a plane having a given angle a in relation to the cylinder axis D at the attached end 30.
The given angle a is between 45° and 75°, for example.
The given angle a depends on the shape of the vehicle around the inlet 18 of the sandbox 12, including the insertion duct, for example.
In a variant, the tube 26 is truncated at the attached end 30 according to any suitable cross-section.
The attached end 30 is intended to be connected to the inlet 18 of the sandbox 12.
The tube 26 forms a cylindrical wall.
The tube 26 here is provided with a radial shoulder 31 at the free end 28, more particularly from the free end 28 towards the cylinder axis D.
The shoulder 31 here is ring-shaped.
The tube 26 has, more particularly consists of, a solid cylindrical section 32 and an open worked cylindrical section 34.

The solid cylindrical section 32 delimits the attached end 30.
The open worked cylindrical section 34 delimits the free end 28.
The open worked cylindrical section 34 represents at least 50% of the tube 26 along the axis D.
The cylindrical wall here has at least one, here a plurality of openings 36, more particularly in the cylindrical open worked section 34.
The opening(s) show at least 75% of the surface area of the cylinder corresponding to the cylindrical open worked section 34.
The cylindrical wall here has four openings, each opening having a cross-sectional area of between 10,000 mm2 and 15,000 mm2, more particularly 12,000 mm2.
The cylindrical wall has no openings in the solid cylindrical section 32.
The bottom 27 is disk-shaped.
The bottom 27 forms a disk-shaped wall.
The bottom 27 is connected to the free end 28 of the tube 26. More particularly, the bottom 27 closes the tube 26 at the free end 28.
The bottom 27 is attached to the shoulder 31 at the free end 28, for example.
The bottom 27 has at least one opening 38, here a single opening 38 in the wall forming the bottom 27.
The opening(s) 38 delimited at the bottom 27 represent at least 75% of the bottom surface.
In the example shown, the single opening 38 corresponds to a disk centered in the middle of the bottom.
The opening 38 has a cross-sectional area of between 3,000 mm2 and 4,000 mm2.
In the example shown, the strainer 20 comprises a shoulder 40 extending from the attached end 30 of the tube 26.
The shoulder 40 extends from the attached end 30 outwardly from the tube 26, i.e. away from the cylinder axis D.
The shoulder 40 here extends in the truncation plane of the tube 26 at the attached end 30.
The shoulder 40 here has an orientation such that when the strainer 20 is secured to the wall of the rail vehicle, here via the spacer 22 as described below, the tube 26 is oriented downward from the inlet 18 to the reservoir 16, here through the insertion duct.
The contents of tube 26 flow to the free end 28 by gravity.
The shoulder 40 surrounds the attached end 30 of the tube 26.
The shoulder 40 is integral with the tube 26, by welding, for example.

The strainer 20 comprises at least one filtering area 41 provided with at least one sieve.
More particularly, the strainer 20 is provided with two sieves.
The at least one sieve is adapted to pass the sand and retain the foreign matter.
The at least one sieve is welded to the strainer 20, for example.
Each at least one sieve has through holes, more particularly for passing sand.
The at least one sieve is a grid, for example.
Each through hole has an area, more particularly between 10 mm2 and 20 mm2, more particularly equal to 16 mm2.
Each through hole has the shape of a square with a side length of 4 mm.
The "area" of the through hole means the cross-sectional area through the through hole.
Each at least one sieve has a percentage of space corresponding to the ratio of the total through hole area to the total sieve area. The percentage of space is between 50% and 78%, more particularly equal to 64%.
The one or more filtering areas 41 extend over only a portion of the strainer 20.
The one or more filtering areas here extend over a portion of the tube and/or a portion of the bottom.
The filtering areas here correspond to the opening(s) 36, 38 delimited by the tube 26 and/or the bottom 27.
The at least one filtering area comprises a first filtration sub-area 42 and a second filtration sub-area 46, in the example shown.
The first filtration area 42 comprises, more particularly here corresponds to the opening(s) 36 delimited by the tube 26.
The first filtration sub-area 42 is provided with a single flexible sieve 47, surrounding the cylindrical open worked section 34, for example. The sieve 47 has a cylindrical shape on the strainer.
The second filtration sub-area 46 here comprises, more particularly corresponds to the opening 38 defined in the bottom 27.
The second filtration sub-area is provided with a single sieve covering the bottom 27, for example. The second filtration sub-area is disk-shaped.
The sieve 47 of the first filtration sub-area 42 and the sieve of the second filtration sub-area 46 have identical filtration parameters. More particularly, the mesh forming the sieves is identical.

The spacer 22 is provided to extend between the shoulder 40 at the attached end 30 and the inlet 18 of the sandbox 12.
More particularly, the strainer 20 is secured to the spacer 22 by securing the shoulder 40 and the spacer 22. The shoulder 40 is screwed to the spacer 22, for example.
The spacer 22 has an inner face, provided to extend against the wall of the vehicle at the inlet 18 and an outer face to which the shoulder 40 is attached.
In the example shown, the shoulder 40 only partially covers the outer face of the spacer 22, specifically a central portion of the outer face of the spacer 22.
The spacer 22, and in particular its inner and outer faces, has a shape and dimensions adapted to cooperate with the inlet 18 on the one hand and the shoulder 40 on the other hand.
The spacer 22 is provided to be fixed to the wall of the vehicle surrounding the inlet 18, by screwing for example.
The spacer 22 is made of metal, for example.
The presence of a spacer makes it possible to adapt a filter model to different vehicle shapes in particular by changing only the spacer, by changing the shape of the inner face and/or the thickness of the spacer and/or the orientation of the inner face with respect to the outer face, for example.
The cover 24 comprises a flap 48, more particularly a crown 50 and the flap 48.
The cover 24 is made of metal, for example.
The crown 50 has a general ring shape.
In the example shown, the crown 50 is attached, screwed for example, to the spacer 22.
The crown 50 extends over a portion of the outer face of the spacer 22 not covered by the shoulder 40.
In a variant, the crown 50 is fixed to the shoulder 40 or to the wall of the vehicle surrounding the inlet 18, for example.
The flap 48 is capable of closing the inlet 18 in a closed position of the flap 48. In the closed position, the flap 48 extends against the crown 50 around the entire periphery.
The cover 24 further comprises a locking element 52 for the flap 48 in its closed position.
The flap 48 is further capable of being moved into at least one open position, in which the inlet 18 is accessible.
The flap 48 is connected to the crown 50 by a hinge 54, for example.

A method for installing the filter as previously described on a rail vehicle will now be described.
In the example shown, the method comprises the following steps:
- providing a filter 10 as previously described,
- attaching the spacer 22 to the vehicle around the inlet 18,
- mounting the cover 24, and
- mounting the strainer 20.
The spacer 22 is screwed to the wall of the vehicle, for example.
In the example shown, the cover 24 is attached, screwed for example, to the spacer 22, specifically to a peripheral portion of the spacer 22.
The strainer 20 is secured to the vehicle by attaching the shoulder 40 of the end connected to the spacer 22, more particularly to a central portion of the spacer 22, which does not intersect with the peripheral portion.
The strainer 20 is screwed to the spacer 22, for example.
The tube 26 then extends from the inlet 18 into the interior of the sandbox.
The tube 26 extends through the insertion duct.
Here, the cylinder axis D of the tube 26 is coincident with the cylinder axis of the insertion duct.
In one embodiment, the cover 24 is attached before the strainer 20.
In a variant, the strainer 20 is attached before the cover 24.
In an alternative embodiment, the cover 24 is attached to the shoulder 40 after the strainer 20 is attached.
In another alternative embodiment, the cover 24 is attached to the wall of the vehicle.
In an alternative embodiment, the filter does not include a spacer, with the strainer and the cover, if present, being attached directly to the wall of the vehicle.
In an alternative embodiment, the filter does not comprise a cover.
A filter according to the invention can thus be used to filter sand at the sandbox inlet, for example, while filling the reservoir during a maintenance operation.
The cylindrical shape of the strainer makes it possible to a quickly fill the reservoir while admitting a large amount of material.
The filter is adapted for easy installation on an existing rail vehicle.
In addition, the filter can be easily mounted and dismounted. This makes it possible to easily replace the filter or certain elements such as the sieve, to change the filtration level or to carry out maintenance operations on the filter.

I/We Claim:
1. A filter (10) for a sandbox (12) of a rail vehicle (14) comprising a strainer (20), the strainer (20) being adapted to be placed at the inlet (18) of a sandbox (12) of a rail vehicle (14), the strainer (20) comprising a tube (26), the strainer (20) comprising at least one filtering area (41) provided with at least one sieve (47), the filter comprising a spacer (22), the tube (26) having an attached end (30) for connection to the inlet (18) of the sandbox (12), the strainer (20) comprising a shoulder (40) extending from the attached end (30) of the tube (26), the spacer (22) being adapted to extend between the shoulder (40) and the inlet (18) of the sandbox (12).
2. The filter according to claim 1, wherein the at least one filtering area (41) extends over only a portion of the strainer (20).
3. The filter according to claim 1 or 2, wherein the strainer (20) comprises a bottom (27), the tube (26) extending between a free end (28) and an attached end (30), the attached end (30) being intended for connection to the inlet (18) of the sandbox (12), the bottom (27) being attached to the free end (28) of the tube (26) and closing the tube (26) at the free end (28).
4. The filter according to claim 3, wherein the at least one filtering area (41) extends over only a portion of the tube (26) and/or a portion of the bottom (27).
5. The filter according to any one of claims 1 to 4, wherein the strainer (20) is screwed to the spacer (22).
6. The filter according to any one of claims 1 to 5, wherein the sieve (47) has through holes, each through hole having an area of between 10 mm2 and 20 mm2.
7. The filter according to claim 3, wherein the at least one filtering area (41) comprises a first filtering sub-area (42) arranged on a portion of the tube (26) and a second filtering sub-area (46) arranged at the bottom (27), with each filtering sub-area (42, 46) provided with a respective sieve (47).

8. A rail vehicle (14) comprising a sandbox (12) having an inlet (18) and a filter (10) according to any of claims 1 to 7, with the filter (10) attached to the inlet (18) of the sandbox (12).
9. A method for placing a filter (10) at an inlet (18) of a sandbox (12) of a rail vehicle (14), comprising the following steps:

- providing a strainer (10) according to any of claims 1 to 7, and
- attaching the strainer (20) of the filter (10) to a wall of the vehicle (14) surrounding the inlet (18) of the sandbox (12), the tube (26) extending from the inlet (18) of the sandbox (12) to a reservoir (16) of the sandbox (12).