SKIP HOIST OF A BLAST FURNACE

Abstract

A skip hoist of a blast furnace includes a winch system. In order to provide an improved drive system for a skip hoist of a blast furnace, the winch system includes a winch drum, rotatably mounted about a drum axis; at least three drive motors; and a transmission for transferring a drive force from each of the drive motors to the winch drum.

The skip hoist further relates to a blast furnace.

Claims

1. A skip hoist of a blast furnace, with a winch system that comprises: a winch drum, rotatably mounted about a drum axis (A); at least three drive motors; and a transmission configured for transferring a drive force from each of the drive motors to the winch drum.

2. The skip hoist according to claim 1, wherein the winch system has a nominal power configured, for optimum operation of the skip hoist, and the drive motors have individual power outputs selected wherein in case of a failure of one drive motor, the combined power output of the other drive motors is at least 100% of the nominal power.

3. The skip hoist according to claim 2, comprising at least four drive motors.

4. The skip hoist according to claim 2, wherein in case of a failure of one drive motor, the combined power output of the other drive motors is at maximum 110% of the nominal power.

5. The skip hoist according to claim 1, wherein the transmission comprises a main gear that is connected to the winch drum and rotatable about the drum axis, and a plurality of drive gears circumferentially arranged about the main gear and adapted to interface with the main gear, wherein each drive gear is coupled to a drive motor.

6. The skip hoist according to claim 5, wherein the main gear is a cylindrical gear with outer teeth.

7. The skip hoist according to claim 5, wherein at least one drive gear is rotatable about a gear axis that is parallel to the drum axis.

8. The skip hoist according to claim 7, wherein at least one drive gear is a cylindrical gear with outer teeth.

9. The skip hoist according to claim 5, wherein at least one drive motor is connected to a drive gear by a drive transmission.

10. The skip hoist according to claim 9, wherein the main gear and the drive gears are at least partially disposed in a main casing and each drive transmission is disposed in a drive casing.

11. The skip hoist according to claim 10, wherein the drive motor is mounted to the drive casing to be at least partially supported by the drive casing.

12. The skip hoist according to claim 11, wherein the drive gear is connected to the drive casing and is adapted to be removed from the main gear together with the drive casing.

13. The skip hoist according to claim 12, wherein the drive casing is connected to and at least partially supported by the main casing.

14. The skip hoist according to claim 13, wherein the drive casing is connected to the main casing by a connecting flange mounted circumferentially around an access opening of the main casing, which access opening has a cross section larger than a cross section of the drive gear.

15. A blast furnace comprising: a furnace shaft; a top charging installation at the top of the blast furnace, for charging raw material to the furnace shaft; and a skip hoist according to claim 1, comprising at least one inclined track for a skip car, the at least one track leading from ground level to the top of the furnace, the at least one skip car being connected to a cable that is operated by the winch system, and being adapted for transporting raw material from ground level to the top of the blast furnace and charging the raw material to the top charging installation.

16. The skip hoist according to claim 2, comprising at least five drive motors, more preferably at least six drive motors.

17. The skip hoist according to claim 2, comprising at least six drive motors.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Preferred embodiments of the disclosure will now be described, by way of example, with reference to the accompanying drawings, in which:

[0031] FIG. 1 is a perspective view of winch system for an inventive skip hoist;

[0032] FIG. 2 is a perspective view of the winch system from FIG. 1 with some elements removed;

[0033] FIG. 3 is a perspective view of a drive assembly of the winch system from FIG. 1; and

[0034] FIG. 4 is a sectional view of a portion of the winch system from FIG. 1.;

[0035] Throughout FIGS. 1 to 4, similar or identical elements are identified by identical reference signs.

DETAILED DESCRIPTION OF THE DRAWINGS

[0036] FIGS. 1 to 4 show an winch system 1 for an inventive skip hoist of an inventive blast furnace. In this example, the lifting capacity of the skip hoist is 39-45.5 t, the lifting height is 96 m and the duration of one lifting operation is 40-60 s.

[0037] The winch system 1 comprises a winch drum 2 that is rotatably mounted about a drum axis A with respect to a stationary base 20. In operational state, the winch drum 2 receives a cable (not shown) for moving one or normally two skip cars of the skip hoist. The winch drum 2 is driven by six drive motors 8 that are aligned parallel to the drum axis A. For instance, each drive motor 8 can be a 200 kW motor with 4 poles, operating at 1500 rpm and 400 V and having a nominal driving moment of 1282 Nm and a maximum driving moment of 2820 Nm. The drive force from the individual drive motors 8 is transferred to the winch drum via a transmission 3. The transmission comprises a main gear 4 that is fixedly connected to the winch drum 2 and therefore rotatable about the drum axis A. The main gear 4 is designed as a spur gear with a hollow center. Six drive gears 6 are disposed around the circumference of the main gear 4. Each drive gear 6 is a spur gear having outer teeth that are meshing with the teeth of the main gear 4 and is rotatable about a gear axis B. All of the gear axes B are parallel to the drum axis A. Since the total drive force necessary for operating the winch drum 2 is divided among a total of six drive motors 6, the load on the teeth of the drive gears 6 and the main gear 4 is only low to moderate, thus increasing the life time of the winch system 1.

[0038] The main gear 4 and the drive gears 6 are disposed in a main casing 12 that has been removed in FIG. 2, along with other components of the winch system 1. Each drive gear 6 is part of a drive assembly 5 that is shown in FIG. 3. Apart from the drive gear 6, the drive assembly 5 comprises a drive casing 9 that houses a drive transmission 7, and one drive motor 8. The drive motor 8 is connected to and at least partially supported by the drive casing 9. This connection is partially established by two support beams 11 that extend parallel to the gear axis B. The drive assembly 5 is designed to be installed into or removed from the winch system 1 as a whole. In other words, the drive motor 8 is connected and aligned to the drive casing 9 before the entire drive assembly 5 is connected on-site to the winch system 1, or more specifically, to the main casing 12. Likewise, the drive gear 6 is connected to the drive transmission 7 and to the drive casing 9 before the entire drive assembly 5 is installed to the winch system 1. Therefore, all components of the drive assembly 5 can be aligned off-site, which greatly facilitates installation and replacement. The drive casing 9 is connected to the main casing 12 by a connecting flange 10 that is disposed circumferentially around a circular access opening 13 in the main casing 12. The connecting flange 10 is connected to the main casing 12 by a plurality of bolts 14. In order to remove the drive assembly 5 from the main casing 12, the bolts 14 are unscrewed and the drive assembly 5, including the drive gear 6 can be removed in the direction of the gear axis B. In order to facilitate this process, a cross-section of the access opening 13 is bigger than a cross-section of the drive gear 6, wherefore the drive gear 6 can be moved out of the main casing 12 through the access opening 13.

[0039] The individual power outputs and the number of the drive motors 8 is selected so that repair or replacement of a drive assembly 5 can be carried out without any longer shutdown of the winch system 1 or reduction of the operability of the blast furnace. By way of example, the winch system 1 has a nominal power of 1000 kW. This power is necessary for normal, optimum operation of the skip hoist. With all six drive motors 8 operating, the total power output is 1200 kW. Thus, there is an unused backup of 200 kW, which is moderate and thus not uneconomical. However, if one of the drive motors 8 fails and the drive assembly 5 of this drive motor 8 is removed from the winch system 1, the remaining five drive motors 8 still have a combined power output of 1000 kW, corresponding to 100% of the nominal power. Therefore, operation of the skip hoist only needs to be interrupted shortly for removing the drive assembly 5 and later on for reinstalling the drive assembly 5 (or a replacement drive assembly 5). Since all components of the drive assembly 5 have been connected and aligned with respect to each other off-site, the necessary time for installation is also reduced.

[0040] The winch system 1 can be adapted easily to a different nominal power. For instance, for a skip hoist with a nominal power of 800 kW, one drive motor 8 and its drive assembly 5 can be omitted, while the rest of the winch system 1 can remain largely unchanged. In the simplest case, the necessary adaptation would be to close the corresponding access opening 13. For a skip hoist with a nominal power of 1400 kW, two additional drive assemblies 5 can be added, which may only necessitate redesigning the main casing 12 to have eight access openings 13 that allow for installation of eight drive assemblies 5. However, no redesign of the drive assembly is necessary.