The use of hoppers on railway trains to store sand is widely known, the sand being dispensed onto the line if there is too little adhesion between the wheel and the track. The sand may be dispensed at a fixed rate such as 2 kg/min when required, using a compressed air system; alternatively it may be dispensed in accordance with the speed of the vehicle as suggested in EP 0 217 636 (Mitsubishi), or in accordance with a measure of the adhesive force, as suggested in WO 00/71399 (AEA Technology). In any event, at intervals the hopper will need to be re-filled. In a known apparatus the hopper is provided with an inlet port and an outlet port; to re- fill the hopper an air outlet pipe is connected to the outlet port, and a sand inlet pipe is connected to the inlet port, the other end of the sand inlet pipe extending into a container of sand, so the sand can be conveyed into the hopper by a stream of air. Where the hopper is installed below the body of the vehicle, this is straightforward since the hopper can readily be accessible from outside the vehicle; but if the hopper is within the body of the vehicle (for example because there is no available space below the body) such a refilling procedure is inapplicable. Although such a hopper may be re-filled manually, for example by someone carrying a sack of sand into the vehicle, this is not an ideal solution for passenger vehicles.

According to the present invention there is provided a filling device for a sand hopper, the device comprising a mounting means for fixing to a port in the base of the

sand hopper, and two ducts extending through the mounting means for insertion into the sand hopper, the ducts having openings within the hopper and remote from the mounting means that face in different directions, and the ducts terminating at respective ports outside the mounting means.

In a second aspect the present invention provides a sand hopper within a body of vehicle, having a filling device mounted in the floor of the vehicle, the device comprising two ducts extending through the floor to extend into the sand hopper, the ducts having openings within the hopper and remote from the floor that face different directions, and the ducts terminating at respective ports outside the body of the vehicle.

In a preferred embodiment the two ducts are defined by a single tube of square cross-section, split in two by a diagonal plate. Preferably the directions in which the ducts face are at least 90° apart.

Preferably the mounting means defines a flow chamber through which sand may flow from the hopper to a sand dispensing device. For example it may comprises two spaced apart flanges with a wall defining a flow chamber between the flanges, the ducts extending through the wall to the said ports outside the flow chamber. The first flange is adapted for fixing to the port in the base of the sand hopper, while the second flange is adapted for fixing to a sand dispensing device.

The invention will now be further and more particularly described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of a sand hopper

filling device of the invention; Figure 2 shows a longitudinal sectional view of the device of figure 1 on the line 2-2; and Figure 3 shows a side view, partly broken away, of a railway vehicle incorporating the device of figure 1.

Referring to figures 1 and 2, a sand hopper filling device 10 comprises a wall defining a rectangular flow chamber 12, the flow chamber 12 being open at its top and bottom. There are rectangular external flanges 14 and 15 at the top and bottom of the chamber 12, with holes 16 for bolts (not shown), the upper flange 14 hence enabling the device 10 to be attached to the underside of a hopper 18 (shown in figure 3), and the lower flange 15 enabling a sand dispensing device 20 (shown in figure 3) to be attached underneath it. Nuts 17 are welded to the lower flange 15 in line with the holes 16. By way of example the chamber 12 may be 76 mm by 51 mm, and of height 53 mm.

A square duct 22,32 mm square, extends from near the bottom of the flow chamber 12 upwardly to project a distance of 200 mm above the upper flange 14. The duct 22 defines two triangular ducts 23,24 by virtue of a steel web 25 extending diagonally across it; and at its lower end the duct 22 is sealed by a cap 26 (see figure 2). The duct 22 is supported by two pipes 27 and 28 extending at right angles, which are welded through respective circular apertures in the wall of the chamber 12 and the wall of the duct 22, so that one pipe 27 communicates with the triangular duct 23 and the other pipe 28 communicates with the other triangular duct 24.

The outer ends of the pipes 27 and 28 are of different diameters (38 mm and 25 mm respectively), acting as ports

for connection to appropriate vacuum hoses (not shown).

At the top end of the duct 22 two openings 30 are defined on opposite walls, each 26 mm square. Furthermore the top end of the duct 24 is sealed by a triangular cap 32. All the components of the device 10 may be of steel, the components being welded together, and subsequently coated (for example with paint) to prevent corrosion.

Referring in particular to figure 3, the device 10 is designed for use with a railway vehicle 34 in which a sand hopper 18 is within the body 35, so that sand can flow out of the hopper 18 through a port in the floor 36.

Such a hopper might be designed to be filled by pouring sand into it after removing a lid; this requirement is avoided by use of the device 10. Rather than attaching the sand dispensing device 20 directly to the bottom of the hopper 18, the device 10 is arranged so the duct 22 projects into the hopper 18 (the duct 22 being long enough to extend to near the top of the hopper 18), the upper flange 14 being attached to the floor 36 and the sand dispensing device 20 being attached to the lower flange 15. The flow chamber 12 hence forms a continuation of the hopper 18. The device 20 is only shown diagrammatically ; when it is activated it causes a jet 38 of sand to be dispensed onto the rail 40 in front of a wheel 42 of the vehicle 34. The device 10 does not effect operation of the dispensing device 20, because the duct 22 and the pipes 27 and 28 do not significantly impede flow of sand through the chamber 12.

The filling device 10 enables the hopper 18 to be re-filled from outside the vehicle 34, for example using a sand storage container and an air suction unit (not shown). The port 27 is connected by a 3. 3 m long and 38 mm internal diameter vacuum hose (not shown) to the air

suction unit, and the port 28 is connected by a 3.3 m long and 25 mm internal diameter vacuum hose (not shown) to a sand suction tube within the storage container. The operator then actuates the electric motor of the air suction unit, which is typically 2 or 3 kW. This sucks air through the duct 23 from the hopper 18, and hence sucks air up the duct 24. Air is therefore sucked up from the sand suction tube. Consequently sand is conveyed with the air stream into the sand hopper 18, where it falls out of the air stream. The sand and air entering the hopper 18 emerge in the general direction of the arrow S of figure 2, while the air being sucked out of the hopper 18 leaves in the general direction of the arrow A. When the hopper is full, the operator switches off the air suction unit, and disconnects the vacuum hoses. It will be appreciated that alternatively the filling system might be pressurized, with a pressurized stream of air and sand being supplied to the port 28, and the resulting air leaving through the port 27, or vice versa.