US 20080252082 A1
A sand spreading device in rail-borne high-speed vehicles in which a metering device and a conveying device are provided. For preventing a lateral discharge of the conveyed sand, both devices do form one unit, yet are separately controllable. When using a bucket wheel (Z) controlled by a vehicle speed indicator (FT), it will be possible to achieve an exact, infinitely variable amount of sand, or conveyance, respectively.
1. A sand spreading device in rail-borne vehicles, in particular in high-speed vehicles, using a metering device and a conveying device, characterised in that both devices form one unit, yet are separately controllable.
2. The sand spreading device according to
3. The sand spreading device according to
In vehicles of this type, a back pressure is created by the relative wind in the region of the wheel surface, which back pressure generates a transverse flow as a function of the wheel geometry, whereby the sand spread is laterally blown out and, thus, does not have the effect to be achieved.
DE 102 52 466 A1 discloses a compressed-air-operated sand spreading device in which the compressed air sucks in the sand from a suck-on space via a nozzle, on the one hand, and blows it into the sand duct, on the other hand. The ratio of the amount of compressed air supplied to the nozzle and to the sand duct is adjusted via a throttle valve.
DE 41 27 016 C2 discloses a sand spreader for a locomotive in which the sand supply means is adjustable as a function of the travelling speed.
The invention has as its object to provide measures by which this problem is solved. Starting out from a metering device and a conveying device for the sand or the like to be spread on the rails, this object is achieved in that both devices can be regulated independently of each other.
If the sand supply is effected by means of compressed air, the rate of the sand conveyance can be increased by increasing the air-pressure. In this case, the air flow forming in the wheel/rail region can no longer discharge the sand from the pressure region.
Further details of the invention will be explained by way of the accompanying drawings in which, in a simplified illustration,
By means of an injector J, the sand conduction SL from a sand container via a metering device, e.g. a bucket wheel Z driven by a motor M to a metering piston or the like and into the conveying air flow is ensured.
The two functional units, i.e. the system controlled by a piston or a bucket wheel, on the one hand, and by the injector, on the other hand, do form one unit, yet with control means separate from each other.
Only in this way it is possible to regulate also the air flow separately, and to adapt it such that the desired effect can, in fact, be attained in the wheel/rail region.
The solution described provides for the flow profile resulting in the wheel/rail region from the travelling speed (transverse flow) to be overcome by increasing the pressure of the sand-conveying air tube, air volume, or by higher conveying speeds, respectively.
As a consequence of the highly different speed profiles—to more than 300 km/h—also the transverse flows occurring in the problem region accordingly differ greatly in intensity.
As a result, it is recommendable also to regulate the above-indicated increase in the pressure of the sand-conveying air flow in correlation with the respective travelling speed.
This regulation is effected by means of a speed-dependant regulating signal (commonly electrically, as 0-10V (DC) or 4-20 mA signal DRS) on a proportionately adjustable pressure regulating means DR, which is connected to a compressed air duct DL.
The advantage is a reduced consumption of compressed air and, thus, reduced costs of energy.
When using a bucket wheel as metering means, which is controlled by a vehicle speed indicator FT, it will be possible to achieve a finely metered amount of sand also in high-speed vehicles.