EP3209962B1 - Device for cooling a shaft furnace distribution chute support trunnions - Google Patents

Description

Technical area

The present invention relates to a device for cooling the support pins of a distribution chute of a charging installation of a shaft furnace, such as a blast furnace.

State of the art

Such an installation typically comprises a fixed feed channel disposed vertically in the center of the top, centered on the vertical axis of the furnace, and a distribution trough for distributing in the furnace the charged materials arriving through said channel. To enable the dispensed material to be dispensed adequately, the dispensing chute is rotatable along said vertical and pivoting axis along a horizontal axis. To this end, the chute is typically pivotally mounted along said horizontal axis in a ferrule mounted coaxially around said feed channel and rotatable along the vertical axis. The chute is pivotally mounted in the shell by means of generally cylindrical pins of horizontal axis, on which the chute is secured and which are rotatably mounted along said horizontal axis in integral bearings of the ferrule. The rotation of the ferrule and the pivoting of the chute are generally provided by gear means located in an annular chamber surrounding the ferrule.

The chute is fixed on both radially inner ends, directed towards the vertical axis of the furnace, journals, which are pivotally driven through the gear drive means located in said chamber surrounding the ferrule. These drive means can act directly on the journals by meshing, or by means of arms or levers.

The journals therefore have an inner end portion which is located inside the ferrule, and which is therefore exposed directly to the intense heat prevailing in the shaft furnace. In addition, they also receive conduction heat from the chute, itself fully exposed to the heat of the oven. To ensure the cooling of the trunnions, and possibly of the trough, it is known to circulate cooling water in channels formed in the trunnions, the cooling water being fed into the trunnions by their opposite outer end ends. at the inner ends on which the chute is fixed. Generally, because the journals are rotatable, rotating joints are used mounted axially on the outer end ends of the journals to provide the connection between the internal channels of the journals and the cooling water supply circuit, fixed on the ferrule, as notably indicated in DE4216166 .

To ensure the pivoting of the chute, a planetary gearbox drive system has recently been developed, which is directly linked to the external end ends of the trunnions. In practice, the journals are directly linked to the gearbox output shaft. It follows that there are no longer end faces of the accessible trunnions, and therefore that the cooling circuit can no longer be connected to the trunnion cooling channels as in the prior art, by joints turners attached to said outer end ends.

Object of the invention

The present invention is intended to provide a solution to this problem, so as to ensure proper cooling of the trunnions, and possibly the chute when it is not desired or it is impossible to connect the circuits water supply on the outer end of the trunnions. More generally, the invention aims to provide a new system for the supply and return cooling cooling water pins, to overcome the rotating joints conventionally used.

With these objectives in view, the invention relates to a device for cooling the support pins of a distribution chute of a charging installation of a shaft furnace, such as a blast furnace, the chute being mounted pivoting along a horizontal axis on a ferrule coaxial in the oven, the chute being rotatably connected to the journals driven in rotation by drive means, the journals having internal cooling channels. According to the invention, the cooling device comprises supply and return ducts for the cooling water flowing in the inner channels, the supply and return ducts being connected to the trunnions by fittings fixed on the cylindrical surface of the trunnions, and the supply ducts and return are arranged to allow the rotary movement of the connectors around the pivot axis of the chute (that is to say around the axis of rotation of the trunnions), during pivoting thereof.

General description of the invention

The connection of the cooling ducts on the periphery of the trunnions thus makes it possible to bring the cooling water into the internal channels of the trunnions from the cylindrical outer surface of the trunnions, instead of providing this connection via the outer end face, which can therefore in particular be connected directly to the rotating drive means.

Preferably, the supply and return ducts are flexible ducts connected directly to the trunnions by screwed connections, but could also be formed of rigid pipes connected with rotating connectors.

According to a particular arrangement, the journals are rotatably mounted inside bearings integral with the shell and the supply and return ducts pass through oblong slots provided in the bearings, the oblong slots extending circumferentially over a length predetermined arc so as to allow the rotary movement of the connections of the supply ducts and return in said lights during pivoting of the chute and trunnions.

Each trunnion may be directly rotatably connected at its end to the output shaft of a gear reducer located on the horizontal pivot axis of the trunnions. The reducer can be a planetary reduction gear train directly driving the trunnions. The journals are then linked directly to the output shafts of the planetary gearheads.

It will be understood that the aforementioned bearings, coaxially traversed by the trunnions, do not necessarily have, in the spirit of the invention, a function of direct support and guiding in rotation of the trunnions. Indeed, because the pins are directly connected in rotation on the shaft of output of the gearbox, the rotation guide and the support of the pins can be provided by the output shaft of the gearbox itself, output shaft which is guided in a housing of the gearbox, which housing is fixed on an outer end of said bearings. In this case, a radial clearance is preferentially formed between the journals and the bearings, and a seal is arranged between the journal and the bearing, axially located between the end of the landing opening inside the shell and the lights where pass the connections of the flexible ducts.

Reducers also serving to support the trunnions could also be fixedly mounted relative to the ferrule by any suitable means, without requiring bearings as mentioned above, by means of only sealing means between the trunnions and the ferrule at the passage of trunnions through the wall of said ferrule.

Also preferably, the flexible conduits are connected to the journals at substantially diametrically opposite points.

According to another complementary arrangement, the output shaft of the gearbox enters a bore of the trunnion, where it is connected in rotation, and the internal cooling channels extend in the trunnion, between the connections of the supply ducts and back, between the bore and the outer surface of the pin. Preferably, the internal cooling channels also extend between the bottom of the bore and the end of the trunnion bearing the chute. These arrangements make it possible in particular to ensure efficient cooling of the trunnion and prevent excessive heat transmission from the chute to the drive reducer via the trunnions.

Brief description of the drawings

• Fig. 1: est une vue en perspective d'un des deux dispositifs de support et d'entrainement en pivotement de la goulotte de distribution d'un haut fourneau;
• Fig. 2: est une vue en perspective du seul tourillon montrant ses moyens de liaison avec un arbre de sortie d'un réducteur d'entraînement en rotation ainsi que ses circuits de refroidissement interne et les flexibles d'alimentation en eau.

Other features and features of the invention will become apparent from the detailed description of an embodiment shown below, by way of illustration, with reference to the accompanying drawings. These show:

• Fig. 1 : is a perspective view of one of two support devices and pivoting of the dispensing chute of a blast furnace;
• Fig. 2 : is a perspective view of the only journal showing its connection means with an output shaft of a rotating drive gearbox as well as its internal cooling circuits and water supply hoses.

Description of a preferred execution

On the drawing of the figure 1 we see the ferrule 1 of the blast furnace loading device, rotatable along a vertical axis A1 of the blast furnace, and on which is secured a bearing 2, carrying at its end a gearbox 3 for the pivoting drive of the chute, no represented along a horizontal axis A2. The gearbox 3 comprises a housing 31 fixed on the outer end 21 of the bearing 2 by a flange 32.

The support trunnion 4 of the chute, shown figure 2 , comprises towards its inner end 40, oriented towards the axis A1, a housing 41 arranged to receive support tabs of the chute, which are rigidly held in a manner known per se. The other end of the pin 42 is rigidly connected to an output shaft of the gearbox 3, which output shaft is supported and guided in rotation in the housing 31. To this end, the pin has a blind bore 45 of diameter adapted to receive with no radial clearance the end of the output shaft of the gear, the rotational connection of said shaft and the pin being provided for example by a key which shows the groove 48 formed in the bore 45.

The pin 4 is located in the bearing 2 but, as already mentioned, it is the rotational guidance of the output shaft of the reducer in the housing 31 which supports and guiding the rotation of the pin. Therefore, the trunnion does not need to be supported and guided in the bearing 2, and a radial clearance, for example of the order of 1 mm, is provided between the trunnion 4 and the bore of the bearing 2 crossed by said pin.

Oblong slots 22 are formed, in substantially diametrically opposed positions, in the wall of the bearing 2 between the ferrule 1 and the outer end 21 of the bearing 2. Cooling water supply hoses 5 are connected in positions substantially diametrically opposed, on the trunnion, by connectors 51 screwed on the trunnion, providing the sealed connection between the flexible pipes 5 and the inner cooling channels 43, 47 of the trunnion, represented by the dotted lines 43. The internal cooling channels extend in the trunnion, between the connectors 51, by portions of channels 43 extending longitudinally and / or in an arc of a circle between the bore 45 and the external surface of the trunnion. In addition, a portion 47 of these channels extends, for example radially, between the bottom 46 of the bore 45 and the inner end 40 of the pin. Thus, the circulation of coolant in the trunnion provides efficient cooling preventing heat transfer from the trough to the reducer 3.

The opposite ends 52 of the hoses are connected to the fixed cooling circuit, not shown, housed in the chamber surrounding the shell 1 and rotating with said ferrule. The connectors 51 pass into the slots 22, which extend over a sufficient arc length to allow free movement of the connectors 51 during pivoting of the journal and therefore of the chute. This arc length will therefore be at least equal to the value of the maximum swing angle in use of the chute, plus the length necessary to take account of the bulk of the connectors 51. The corresponding range of rotation is typically 30 to 50 degrees, preferably 45 degrees.

Because of the clearance between the pin 4 and the bearing 2, it could occur leaks gas contained in the blast furnace tank by this space and the lights 22. To seal, a seal, for example a braid sealing, is placed between the journal and the bearing, for example in a groove 44 provided for this purpose in the journal, the seal being axially located between the inner end of the bearing 2 and the slots 22 pierced in the wall of the bearing .

Claims (12)

1. A device for cooling the supporting trunnions (4) of a distribution spout of a charging installation of a shaft furnace, such as a blast furnace, the spout being mounted pivotably about a horizontal axis (A2) on a shell (1) coaxial with the furnace and the spout being attached rotatably to the trunnions driven in rotation by drive means, the trunnions comprising internal cooling channels (43), characterised in that the cooling device comprises feed and return ducts (5) for the cooling water circulating in the internal channels, the feed and return ducts (5) being connected to the trunnions (4) by connectors (51) fixed to the cylindrical surface of the trunnions, and the feed and return ducts (5) are arranged to permit rotational displacement of the connectors (51) about the pivot axis of the spout during pivoting of the spout.
2. A device according to claim 1, wherein the trunnions are mounted revolvably inside bearings (2) integral with the shell and the feed and return ducts (5) pass through oblong slots (22) provided in the bearings (2), the oblong slots extending circumferentially over a predetermined arc length so as to permit rotational displacement of the connectors (51) of the feed and return ducts (5) in said slots (22) during pivoting of the spout.
3. A device according to claim 1 or 2, wherein each trunnion (4) is directly attached for rotation by its end (42) to the output shaft of a reduction gear (3) located on the horizontal pivot axis (A2) of the trunnions.
4. A device according to claim 3, wherein the trunnions (4) are rotationally guided and supported by the output shaft of the reduction gear (3) which is guided in a crankcase (31) of the reduction gear.
5. A device according to claim 4, wherein the crankcase (31) of the reduction gear (3) is fixed on an outer end (21) of the bearings (2).
6. A device according to claim 4, wherein radial play is provided between the trunnions (4) and the bearings (2).
7. A device according to claim 6, wherein a gasket is arranged between the trunnion (4) and the bearing (2), axially located between the end of the bearing which opens into the interior of the shell and the slots (22).
8. A device according to claim 1, wherein the feed and return ducts are flexible ducts (5) connected directly to the trunnions (4) by screwed connectors (51).
9. A device according to claim 1, wherein the feed and return ducts (5) are connected to the trunnions (4) at substantially diametrically opposed points.
10. A device according to claim 1, wherein the shell (1) is rotatable about the vertical axis (A1) of the furnace and the feed and return ducts (5) 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. A device according to claim 3, wherein the output shaft of the reduction gear penetrates into a bore of the trunnion, where it is attached rotatably, and the internal cooling channels (43) extend into the trunnion, between the connectors (51) of the feed and return ducts and between the bore (45) and the outer surface of the trunnion.
12. A device according to claim 11, wherein the internal cooling channels (47) also extend between the bottom (46) of the bore (45) and the end (40) of the trunnion bearing the spout.

Images