Granular material metering device and method

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. A method, comprising: actuating a metering piston of a metering device to form a gap between a feed of the metering device and a metering chamber of the metering device, the feed configured to receive granular material from a container, the gap configured to permit the granular material to flow from the feed to the metering chamber; 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 responsive to detecting the blockage, actuating the metering piston to enlarge the gap between the feed and the metering chamber to disperse the blockage.

2. The method of claim 1, further comprising: actuating the metering piston to reduce the gap after a predefined duration following actuating the metering piston to enlarge the gap.

3. The method according to claim 2, wherein the predefined duration is a value no less than 100 ms and no greater than 1 s.

4. The method according to claim 1, wherein the metering piston is pneumatically actuated using compressed air.

5. The method according to claim 4, wherein actuating the metering piston to form the gap having the first size comprises controlling a valve to supply a first pressure of compressed air to the metering device, and actuating the metering piston to enlarge the gap comprises controlling the valve to supply a larger second pressure of the compressed air to the metering device.

6. The method according to claim 1, wherein the metering piston is electromagnetically actuated by lifting magnets.

7. The method according to claim 1, wherein actuating the metering piston comprises moving the metering piston against a return spring away from a closed position, wherein the metering piston closes the gap between the feed and the metering chamber while in the closed position.

8. The method according to claim 1, further comprising: delivering the granular material via the delivery line to an interface between a rail and a wheel to change friction between the rail and the wheel.

9. A system comprising: a metering device comprising: a feed configured to receive granular material from a container; a metering chamber configured to direct the granular material into a delivery line leading away from the metering chamber; and a metering piston configured to control flow of the granular material between the feed and the metering chamber; at least one optical sensor arranged in the delivery line; and a control device operably connected to the metering device and the at least one optical sensor, the control device configured to actuate the metering piston to form a gap between the feed and the metering chamber to permit the granular material from the feed to the metering chamber, the control device configured to detect a blockage of the granular material based on the at least one optical sensor, and to actuate the metering piston to enlarge the gap between the feed and the metering chamber to disperse the blockage.

10. The system according to claim 9, wherein the metering device comprises an adjusting screw that is adjustable to change a size of the gap.

11. The system according to claim 9, wherein the metering piston is connected to at least one return spring that biases the metering piston towards a closed position that closes the gap between the feed and the metering chamber.

12. The system according to claim 9, further comprising: at least one valve connected to the control device, the control device configured to control the at least one valve for pneumatic actuation of the metering piston.

13. The system according to claim 12, wherein the control device is configured to actuate the metering piston to form the gap by controlling the at least one valve to supply a first pressure of compressed air to the metering device, and the control device is configured to actuate the metering piston to enlarge the gap by controlling the at least one valve to supply a larger second pressure of the compressed air to the metering device.

14. The system according to claim 9, wherein the metering device comprises lifting magnets connected to the control device, the control device configured to independently control power to the lifting magnets for electromagnetic actuation of the metering piston.

15. The system according to claim 9, wherein the control device is configured to actuate the metering piston to reduce the gap after a predefined duration following actuating the metering piston to enlarge the gap.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is explained in detail with reference to the appended drawings. In the drawings:

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

(3) FIG. 2 shows an embodiment of a metering device with pneumatically actuated metering piston;

(4) FIG. 3 shows a further embodiment of a metering device with electromagnetically actuated metering piston;

(5) 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

(6) FIG. 5 shows a time diagram of the control of the metering piston to disperse a blockage according to a predefined time grid.

DETAILED DESCRIPTION OF THE INVENTION

(7) 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.

(8) 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 ?t.sub.i, the metering piston 7 can be actuated for a predefined duration ?t 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+?d so that any blockages are dispersed. The second distance d.sub.2 or the additional distance ?d 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.

(9) 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 ?t.sub.i, the metering piston 7 can be actuated for a predefined duration ?t 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+?d, so that any blockages are dispersed.

(10) 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 ?t. 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.

(11) 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 ?t.sub.i. This variant is simpler compared with that shown in FIG. 4 but is associated with a higher consumption of granular material 2.

(12) 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.