DEVICE FOR COOLING A SHAFT FURNACE DISTRIBUTION CHUTE SUPPORT JOURNALS

Abstract

A device for cooling the supporting trunnions of a distribution spout of a charging installation of a shaft furnace, wherein the spout is mounted pivotably about a horizontal axis on a shell coaxial with the furnace and the spout is attached rotatably to the trunnions driven in rotation by a drive component. The trunnions are directly attached for rotation by their ends to output shafts of reduction gears and include internal cooling channels. The cooling device includes feed and return ducts for the cooling water circulating in the internal channels. The feed and return ducts are connected to the trunnions by connectors fixed to the cylindrical surface of the trunnions. The feed and return ducts are arranged to permit rotational displacement of the connectors about the pivot axis of the spout during pivoting of the spout, in particular by passing through oblong slots extending circumferentially in the wall of bearings supporting the driving reduction gears.

Claims

1. A device for cooling the supporting trunnions of a distribution spout of a charging installation of a shaft furnace the distribution spout being mounted pivotably about a horizontal axis on a shell coaxial with the furnace and the distribution spout being attached rotatably to the trunnions driven in rotation by drive means, the trunnions comprising internal cooling channels, wherein the cooling device comprises feed and return ducts for the cooling water circulating in the internal cooling channels, the feed and return ducts being connected to the trunnions by connectors fixed to the cylindrical surface of the trunnions, and the feed and return ducts are configured such that the connectors are rotational displaced about the pivot axis of the distribution spout during pivoting of the distribution spout.

2. The device according to claim 1, wherein the trunnions are mounted revolvably inside bearings integral with the shell and the feed and return ducts pass through oblong slots provided in the bearings, the oblong slots extending circumferentially over a predetermined arc length such that the connectors are rotationally displaced in said slots during pivoting of the distribution spout.

3. The device according to claim 1, wherein each trunnion has an end and is directly attached for rotation by the end to the output shaft of a reduction gear located on the horizontal pivot axis of the trunnions.

4. The device according to claim 3, wherein the trunnions are rotationally guided and supported by the output shaft of the reduction gear which is guided in a crankcase of the reduction gear.

5. The device according to claim 4, wherein the crankcase of the reduction gear is fixed on an outer end of the bearings.

6. The device according to claim 4, wherein there is radial play between the trunnions and the bearings.

7. The device according to claim 6, wherein a gasket is arranged between the trunnion and the bearing, the gasket being axially located between the end of the bearing which opens into the interior of the shell and the slots.

8. The device according to claim 1, wherein the feed and return ducts are flexible ducts connected directly to the trunnions by screwed connectors.

9. The device according to claim 1, wherein the feed and return ducts are connected to the trunnions at substantially diametrically opposed points.

10. The device according to claim 1, wherein the shell is rotatable about the vertical axis of the furnace and the feed and return ducts are connected to a cooling circuit which is stationary relative to the shell, accommodated in the chamber surrounding the shell and revolving with said shell.

11. The device according to claim 3, wherein the output shaft of the reduction gear penetrates into a bore of the trunnion and is attached rotatably, and the internal cooling channels extend into the trunnion, between the connectors of the feed and return ducts, between the bore and the outer surface of the trunnion.

12. The device according to claim 11, wherein the internal cooling channels also extend between the bottom of the bore and the end of the trunnion bearing the distribution spout.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other details and features of the invention will emerge from the following detailed description of an embodiment, provided by way of illustration with reference to the appended drawings, in which:

[0017] FIG. 1: is a perspective view of one of the two devices for supporting and pivotably driving the distribution spout of a blast furnace; and

[0018] FIG. 2: is a perspective view of just the trunnion showing its connection means with an output shaft of a rotational drive reduction gear together with its internal cooling circuits and the water feed hoses.

DETAILED DESCRIPTION OF THE DRAWINGS

[0019] The drawing of FIG. 1 shows the shell 1 of the blast furnace charging device, rotatable about a vertical axis A1 of the blast furnace, and to which is attached a bearing 2 having on the end thereof a reduction gear 3 for pivotably driving the spout, not shown, about a horizontal axis A2. The reduction gear 3 comprises a crankcase 31 fixed to the outer end 21 of the bearing 2 by a flange 32.

[0020] The trunnion 4 for supporting the spout, shown in FIG. 2, comprises towards the inner end 40 thereof, oriented towards the axis A1, a receptacle 41 provided to receive supporting lugs of the spout, which are held rigidly therein in a manner known per se. The other end of the trunnion 42 is connected rigidly to an output shaft of the reduction gear 3, which output shaft is supported and guided rotatably in the crankcase 31. To this end, the trunnion comprises a blind bore 45 of a diameter suitable for receiving the end of the output shaft of the reduction gear without radial play, said shaft and the trunnion being connected rotatably for example by a key, which has a groove 48 provided in the bore 45.

[0021] The trunnion 4 is located in the bearing 2 but, as already mentioned, the trunnion is actually supported and guided rotationally by rotational guidance of the reduction gear output shaft in the crankcase 31. Consequently, the trunnion does not need to be supported and guided in the bearing 2, and radial play, for example of the order of 1 mm, is provided between the trunnion 4 and the bore of the bearing 2 through which said trunnion passes.

[0022] Oblong slots 22 are formed, in substantially diametrically opposed positions, in the wall of the bearing 2 between the shell 1 and the outer end 21 of the bearing 2. Cooling water feed hoses 5 are connected, at substantially diametrically opposed positions, to the trunnion, by connectors 51 screwed onto the trunnion, providing a leakproof connection between the hoses 5 and the internal cooling channels 43, 47 of the trunnion, represented by the dashed lines 43. The internal cooling channels are extended in the trunnion between the connectors 51 by channel portions 43 which extend longitudinally and/or in an arc of a circle between the bore 45 and the outer surface of the trunnion. Furthermore, a proportion 47 of these channels extends, for example radially, between the bottom 46 of the bore 45 and the inner end 40 of the trunnion. Circulation of cooling liquid in the trunnion thus provides effective cooling which prevents the transmission of heat from the spout towards the reduction gear 3.

[0023] The opposite ends 52 of the hoses are connected to the stationary cooling circuit, not shown, accommodated in the chamber surrounding the shell 1 and revolving with said shell. The connectors 51 pass through the slots 22, which extend over a length of arc which is sufficient to permit free displacement of the connectors 51 during pivoting of the trunnion and hence of the spout. This length of arc will therefore be at least equal to the value of the spout's maximum pivoting angle in service plus the length necessary to take account of the space occupied by the connectors 51. The corresponding range of rotation is typically 30 to 50 degrees, preferably 45 degrees.

[0024] Because of the play provided between the trunnion 4 and the bearing 2, leaks of the gas present in the blast furnace shaft could occur via this space and via the slots 22. To ensure tightness, a gasket, for example a braided gasket, is placed between the trunnion and the bearing, for example in a groove 44 provided for this purpose in the trunnion, said gasket being axially located between the inner end of the bearing 2 and the slots 22 cut in the bearing wall.