METHOD FOR CONTROLLING A DEVICE FOR METERING GRANULAR MATERIAL AND METERING DEVICE FOR METERING GRANULAR MATERIAL

Abstract

A method for controlling a device for metering granular material and a metering device for metering granular material comprises a feed for the granular material from a container into a metering chamber. A metering piston can be actuated by a control device such that a gap between the feed and the metering chamber is opened by a predefined first distance and a second distance which is greater than the first distance. At least one sensor is arranged in a delivery line leading away from the metering chamber and is connected to the control device so that the metering piston can be actuated for a predefined duration such that the gap between the feed for the granular material and the metering chamber can be opened by the second distance if a blockage of the granular material is detected by the at least one sensor, so that the blockage is dispersed.

Claims

1-11. (canceled)

12. A method for controlling a device for metering granular material to increase a friction coefficient between a rail wheel and a rail, wherein the granular material is fed from a container and metered into a metering chamber, by actuating a metering piston, whereby a gap between a feed for the granular material and the metering chamber is opened by a predefined first distance and the metering piston is temporarily actuated in such a manner that the gap between the feed for the granular material and the metering chamber is opened by a second distance which is greater than the first distance, the method comprising: detecting a blockage of the granular material with at least one optical sensor arranged in a delivery line leading away from the metering chamber; and actuating the metering piston for a predefined duration in such a manner that the gap between the feed for the granular material and the metering chamber is opened by the second distance when a blockage of the granular material is detected so that the blockage is dispersed.

13. The method according to claim 12, wherein the gap between the feed for the granular material and the metering chamber is opened by the second distance for a predefined duration of 100 ms to 1 s.

14. The method according to claim 12, wherein the metering piston is actuated pneumatically wherein two different pressures are used for actuation of the metering piston.

15. The method according to claim 12, wherein the metering piston is actuated electromagnetically by two lifting magnets.

16. A metering device for metering granular material to increase a friction coefficient between a rail wheel and a rail, the device comprising a feed for the granular material from a container and into a metering chamber, wherein a metering piston can be actuated via a control device in such a manner that a gap between the feed for the granular material and the metering chamber is opened by a predefined first distance and a second distance which is greater than the first distance, wherein at least one optical sensor is arranged in a delivery line leading away from the metering chamber and is connected to the control device so that the metering piston can be actuated for a predefined duration in such a manner that the gap between the feed for the granular material and the metering chamber can be opened by the second distance when a blockage of the granular material is detected by the at least one optical sensor so that the blockage is dispersed.

17. The metering device according to claim 16, wherein the second distance is adjustable by an adjusting screw.

18. The metering device according to claim 16, wherein the metering piston is connected to at least one return spring.

19. The metering device according to claim 18, wherein the metering piston is connected to two compressed air lines for two different pressures and wherein at least one valve connected to the control device is provided for pneumatic actuation of the metering piston.

20. The metering device according to claim 18, wherein the metering piston is connected to two lifting magnets for electromagnetic actuation, said lifting magnets connected to the control device.

Description

[0021] The present invention is explained in detail with reference to the appended drawings. In the drawings:

[0022] FIG. 1 shows a schematic device for metering granular material into the gap between rail wheel and rail to increase the coefficient of friction;

[0023] FIG. 2 shows an embodiment of a metering device with pneumatically actuated metering piston;

[0024] FIG. 3 shows a further embodiment of a metering device with electromagnetically actuated metering piston;

[0025] FIG. 4 shows a time diagram of the control of the metering piston to disperse a blockage depending on the detection of a blockage; and

[0026] FIG. 5 shows a time diagram of the control of the metering piston to disperse a blockage according to a predefined time grid.

[0027] FIG. 1 shows a device 1 for metering granular material 2, in particular sand, into the gap between rail wheel 3 and rail 4 to increase the coefficient of friction. The device 1 for metering granular material 2 is connected underneath a container 5 for the granular material 2 and meters a desired quantity of granular material 2. The desired granular material 2 is delivered via a delivery line 10 into the gap between wheel 3 of a rail vehicle and rail 4 in order to increase the friction between wheel 3 and rail 4. The metering device 1 is controlled via a control device 16 which in the depicted example is connected to a valve 19 via which a compressed air line 17 for a first pressure p.sub.1 or a compressed air line 18 for a pressure p.sub.2 that is higher than the first pressure p.sub.1 is opened pneumatically. If a sensor 10 is arranged in the delivery line 11 which is connected to the control device 16, the metering device 1 can be controlled or regulated depending on a blockage detected by the at least one sensor 10 and then, whenever a blockage is detected, a pulse having the higher second pressure p.sub.2 is delivered to the metering piston 7 of the metering device 1 to disperse the blockage.

[0028] FIG. 2 shows an embodiment of a metering device 1 with pneumatically actuated metering piston 7. In this case, the metering piston 7 is moved away from the feed 9 for the granular material 2 against the first return spring 14 by application of compressed air at a first pressure p.sub.1 with the result that the gap 8 is opened by a first distance d.sub.1. In this way, a normal desired metering of the granular material 2 into the metering chamber 6 takes place. When detecting a blockage or at predefined time points t.sub.1 or in predefined time intervals Δt.sub.i, the metering piston 7 can be actuated for a predefined duration Δt in such a manner that the gap 8 between the feed 9 for the granular material 2 and the metering chamber 6 is opened by a second distance d.sub.2 which is greater than the first distance d.sub.1, namely d.sub.1+Δd so that any blockages are dispersed. The second distance d.sub.2 or the additional distance Δd can, for example, be configured to be adjustable by an adjusting screw 20. Depending on the quality of the granular material 2, the distance d.sub.1 can, for example, be 5 mm and the greater distance d.sub.2 can, for example, be 7 mm.

[0029] FIG. 3 shows a further embodiment of a metering device 1 with electromagnetically actuated metering piston 7. In this case, the metering piston 7 is moved against the first return spring 14 by activation of a first lifting magnet 12 with the result that the gap 8 is opened by a first distance d.sub.1. In this way, a normal desired metering of the granular material 2 into the metering chamber 6 is achieved. When a blockage is detected or at predefined time points t.sub.i or in predefined time intervals Δt.sub.i, the metering piston 7 can be actuated for a predefined duration Δt by actuating the second lifting magnet 13 in such a manner that the gap 8 between the feed 9 for the granular material 2 and the metering chamber 6 is opened by a second distance d.sub.2, which is greater than the first distance d.sub.1, namely d.sub.1+Δd, so that any blockages are dispersed.

[0030] FIG. 4 shows a time diagram of the control of the metering piston 7 for dispersing a blockage depending on the detection of a blockage. Whenever a blockage is detected, an opening of the distance x of the metering piston 7 to the greater distance d.sub.2 is accomplished during a predefined duration At. This variant is characterized by a minimal additional consumption of granular material 2, wherein the somewhat higher expenditure of a detection of the blockage by corresponding sensors 10 must be accepted.

[0031] Finally FIG. 5 reproduces a time diagram of the control of the metering piston 7 to disperse a blockage according to a predefined time grid. In this case, the metering piston is opened by the second greater distance d.sub.2 at predefined time points t.sub.i or predefined time intervals Δt.sub.i. This variant is simpler compared with that shown in FIG. 4 but is associated with a higher consumption of granular material 2.

[0032] The present method for controlling a device 1 for metering granular material 2 and the present metering device 1 makes it possible to achieve an optimal function even in the presence of granular material having different quality since any blockages which occur can be dispersed rapidly and effectively.