EP0572290B1 - Method and apparatus for feeding a zinc ingot into a zinc bath of a galvanizing line - Google Patents

Abstract

Process for feeding a zinc pot (4) with ingots (6, 6'') withdrawn from a storage region by a handling device which comprises a clamp grasping one end (8', 8'') of the ingot (6', 6''), the ingots being brought above the zinc pot (4) and lowered slowly into the latter, characterised by the following operations: - a) the ingot (6') is delivered onto an inclined feeding table (2') whose bottom end (7, 7'') is above the zinc pot (4); - b) the ingot (6', 6'') is slid along the table; - c) when the ingot (6'') has been almost completely immersed in the zinc bath (5), a receptacle (21, 21') held in the zinc bath (5) in a resting position (21') is placed below the unmelted upper end (8'') of the ingot (6''); - d) the said upper end (8'') of the ingot is released; and - e) the said receptacle (21) moves back down into its resting position. <IMAGE>

Description

The present invention relates to galvanizing installations and, more particularly, the device for feeding ingots to the crucible or zinc pot.

The zinc crucibles or pots in galvanizing installations are supplied with zinc ingots which are taken from a storage area by a handling device, such as an overhead crane, which is fitted with a clamp which grasps one end of the ingot. The ingot is brought above the zinc pot and the handling device is actuated in order to slowly lower the ingot into the zinc pot where it melts. When the whole ingot has plunged into the molten zinc, the clamp of the handling device is opened.

This process has the disadvantage that the clamp plunges into the molten zinc and, because this clamp is practically at room temperature, molten zinc is fixed on the clamp which is quickly unusable because it is too clogged.

The operations of unclogging or replacing the pliers cause disturbances in the process of feeding the zinc pots.

Another solution is to open the clamp before it plunges into the bath of molten zinc; but in this case, the not yet melted end of the ingot which can weigh up to 400 to 500 kg suddenly falls into the bath, which creates eddies and therefore modifies the characteristics of the bath, in particular with regard to the film top of the bath.

Another solution is to recover the ends of the ingots in the clamp, which results in a significant expense in labor and installation.

The present invention therefore proposes to provide a method and a device for feeding ingots of zinc from a zinc pot of a galvanizing installation which makes it possible to immerse the entirety of each ingot in the zinc pot without creating disturbances in the zinc bath and without entailing maintenance or replacement operations. equipment.

• a) le lingot est tout d'abord amené sur une table d'alimentation inclinée dont l'extrémité basse se trouve au-dessus du pot de zinc ;
• b) on fait coulisser le lingot le long de la table d'alimentation dans le pot de zinc ;
• c) lorsque le lingot a été presque totalement immergé dans le bain de zinc, un réceptacle, qui est maintenu dans le bain de zinc dans une position de repos, vient se placer en dessous de l'extrémité supérieure non fondue du lingot ;
     d) ladite extrémité supérieure du lingot est libérée ; et
     e) ledit réceptacle redescend dans sa position de repos.

To this end, the subject of the invention is a method of supplying zinc ingots to a zinc pot of a galvanizing line, in which the ingots are removed from a storage area by a handling device such as 'an overhead crane, which includes a clamp gripping one end of the ingot, the ingots being brought above the zinc pot and slowly descended into the latter, characterized by the following operations:

• a) the ingot is first of all brought to an inclined feeding table, the lower end of which is above the zinc pot;
• b) the ingot is slid along the feed table in the zinc pot;
• c) when the ingot has been almost completely submerged in the zinc bath, a receptacle, which is maintained in the zinc bath in a rest position, is placed below the upper non-molten end of the ingot;
  d) said upper end of the ingot is released; and
  e) said receptacle descends to its rest position.

Because the receptacle comes to recover the upper end of the ingot, the latter enters the bath without creating eddies.

Furthermore, the receptacle immersed in the zinc bath is at the temperature of the latter and it does not occur the clogging phenomenon which occurs. on the clamps of supply systems of known type.

According to another characteristic of the invention, the ingot is placed on the feed table while the latter is in a horizontal position, the ingot handling device is removed, retaining means grip one end of the ingot, inclines the table and the retaining means control the sliding of the ingot along the table.

The invention also relates to a device for supplying zinc pots with a zinc pot for a galvanizing line for implementing the above method, characterized in that it comprises a table movable between a horizontal position for receiving the ingots in which it receives one or more ingots and an inclined feeding position in which its lower edge is above the zinc pot, said table comprising means for retaining the ingot or ingots gripping the upper end of the ingot or ingots when it is in the inclined position, said retaining means being actuated to allow the ingot or ingots to descend when the table is in the inclined position, said feeding device comprising, for each ingot carried by the table , a receptacle movable between two positions, a rest position in which it is located in the molten zinc pot and a working position in which it is placed u below the lower edge of the table when the latter is in an inclined position so as to collect the upper end of the ingot when this end is released from said retaining means.

According to one embodiment of the invention, the receptacle moves in translation parallel to the table when the latter is in the inclined position.

Advantageously, the receptacle comprises a guide sliding along the table when the latter is in the inclined position and supporting at its lower end a basket arranged in overhang on said sliding guide so as to come into the working position, below the lower edge of the table when it is in an inclined position.

According to another embodiment of the invention, the sliding guide comprises a slide formed by an inverted U-shaped profile having internal edges and a sliding part constituted by an I-shaped profile and said sliding part is connected by a chain with a motor comprising chain sprockets and a pneumatic or electric geared motor.

According to yet another embodiment of the invention, the receptacle comprises a sliding guide disposed under the table when the latter is in the inclined position and carrying at its lower end a basket coming, in the working position, to be placed under the lower edge of the table.

• la figure 1 est une vue générale d'un dispositif d'alimentation en lingots d'un pot de zinc ;
• la figure 2 est une vue de côté de la table et du réceptacle ;
• la figure 3 est une vue schématique d'un mode de réalisation de l'invention ; et
• la figure 4 est une vue de détail du mode de réalisation de la figure 4.

Other characteristics and advantages of the invention will emerge from the description which follows of an exemplary embodiment, made with reference to the appended drawings in which:

• Figure 1 is a general view of a device for feeding ingots of a zinc pot;
• Figure 2 is a side view of the table and the receptacle;
• Figure 3 is a schematic view of an embodiment of the invention; and
• FIG. 4 is a detailed view of the embodiment of FIG. 4.

Figure 1 shows a carriage 1 mobile on rails and carrying a feed table 2. This table is mounted for rotation about a transverse axis 3 perpendicular to the direction of movement of the carriage 1. This axis of rotation 3 is arranged at the end of the carriage and its distance from the free end of the table is approximately equal to a quarter the length of the latter.

Table 2 is a feed table for a zinc pot 4 in which there is molten zinc, the upper level of the zinc bath being identified at 5.

The feed table 2 can take two positions, a horizontal position for receiving the ingots in which it receives an ingot 6 coming from a storage area and brought via a handling device such as an overhead crane. . The ingot 6 is arranged so as to be in abutment on the free edge 7 of the table 2.

Zinc ingots can have a length of 2.25 m, a width of 0.4 m and a height of 0.35 m, for example. Such an ingot weighs 2,000 kg and its upper end or tail which is gripped by retaining means such as a clamp can weigh from 400 to 500 kg (or a lug using a hole).

The temperature of the molten zinc in the pot is around 450 ° C.

The upper end or tail 8 of the ingot opposite the free edge 7 of the table 2 is gripped by a clamp 9 constituting a device for retaining the ingot and which can move in translation on the table 2 parallel to the longitudinal axis of the ingot 6 The movement of the clamp 9 is controlled by a step-by-step electric motor 11.

Table 2 can take a second feeding position 2 'which is shown in broken lines; the angle of inclination can vary from 30 ° to 90 °; it is for example 60 °. In this feeding position, the free edge 7 of the table 2 is in position 7 'just above the level 5 of the molten bath 5 located in the zinc pot 4. In this position, the ingot 6' is gripped by the clamp 9 '; for this purpose it has a transverse hole 12 respectively 12 '.

The supply device comprises a receptacle 21 which is movable between two positions, a rest position 21 ', which is shown in broken lines in FIG. 2 and its working position 21. In its rest position 21', the receptacle 21 is completely immersed in the molten zinc bath 5. In its working position 21, this receptacle is placed below the free edge 7 ′ of the table in the feeding position while remaining slightly below the upper level 5 of the zinc bath.

In this working position 21, the receptacle collects the end 8 '' of the ingot 6 '' which has been represented in FIG. 2 in the final feeding position, that is to say that only the end upper 8 '' of the ingot is not yet immersed in the bath 5.

When this upper end 8 '' rests in the receptacle 21, the clamp 9 is released and it goes back to the initial position while the receptacle 21 returns to its rest position 21 '' so that the upper end 8 '' of the ingot is immersed in bath 5 and melted.

The table is returned to the ingot reception position, that is to say it is returned to the horizontal position. The assembly is then ready for a new feeding operation.

FIG. 3 represents an embodiment of the invention in which the receptacle consists of a guide 22 which slides along the table 2 when the latter is in the feeding position and of a basket 23 which is arranged in overhang at the lower end of the guide 22 so as to be opposite the free edge 7 'of the table.

As can be seen in FIG. 4, the sliding guide consists of a fixed slide 24 in the shape of an inverted U and of a sliding element 25 constituted by an I-profile. The upper end of the sliding element 25 is integral with a chain 26 which circulates in the slide 24 and which is wound on chain sprockets in a motor 27 comprising a pneumatic or electric gearmotor. The sliding element 25 rolls on rollers 28 carried by the slide 24.

In an exemplary embodiment, the feed table has a length of 3.4 m and a width of 0.5 m. The basket stroke is approximately 5 m, its translation speed being 0.5 m / min. The ingot descent speed, that is to say the speed of movement of the clamp 9, is 2 m / min.

It can be seen that the invention makes it possible to immerse the tails of ingots in the zinc pot without making a stir.

Since the receptacle remains permanently in the molten zinc bath, it is not subject to the clogging phenomenon and therefore does not require any unclogging or replacement operation.

Furthermore, the downward movement of the ingot tail in the bath is done in a controlled manner, that is to say with a speed slow enough not to cause eddies.

The process according to the invention can easily be automated in such a way that no manual intervention is necessary. One can for example provide limit switches for the clamp 9 which control the raising of the receptacle.

The above description has been provided only by way of nonlimiting example and it is obvious that modifications or variants can be made without departing from the scope of the present invention.

Thus we can provide a receptacle consisting of a sliding guide disposed under the table when it is in the inclined position and carrying at its lower end a basket coming, in the working position, to be placed under the lower edge of the table.

Furthermore, provision may be made for feed tables carrying several ingots, for example two. In this case, a mobile receptacle is provided for each of the ingots carried by the table.

Claims (7)

1. Process for feeding zinc ingots (6, 6', 6'') into a zinc bath (4) of a galvanizing line, in which the ingots are taken up in a stacking zone by a handling device such as a rolling bridge, which comprises pincers which grasp one end of the ingot, the ingots being brought above the zinc bath and slowly lowered into the latter, characterised by the following operations:

   - a) the ingot (6, 6', 6'') is firstly brought onto a tilting feeding table (2, 2') the lower end of which is located above the zinc bath;

   - b) the ingot is slid along the feeding table into the zinc bath;

   - c) when the ingot (6, 6', 6'') has been almost completely immersed in the zinc bath (5), a receptacle (20, 21') which is kept in the zinc bath (5) in an inactive position (21'), comes into position under the non-molten upper end (8, 8', 8'') of the ingot (6, 6', 6'');

   - d) said upper end (8, 8', 8'') of the ingot is released; and

   - e) said receptacle descends back to its inactive position (21').
2. Process of feeding zinc ingots (6) into a zinc bath (4) of a galvanizing line according to Claim 1, characterised in that the ingot (6) is placed on the feeding table (2) such that it is located in a horizontal position; in that the handling device is unhooked from the ingot; in that the retaining means (9) grasp one end (8) of the ingot; in that the table is tilted and in that the retaining means control the sliding of the ingot along the table.
3. Device for feeding zinc ingots into a zinc bath of a galvanizing line in order to put into practice the process according to Claim 1 or Claim 2, characterised in that it comprises a table (2, 2') which is movable between a horizontal position (2) for receiving the ingots (6, 6', 6'') in which position it receives one or more ingots (6, 6', 6''), and a tilting position (2') for feeding, in which the lower edge (7') thereof is located above the zinc bath (4), said table (7, 7') comprising means (9, 9') for retaining the ingot or ingots (6, 6', 6'') grasping the upper end (8, 8', 8'') of the ingot or ingots (6, 6', 6'') when it is in the tilted position (2'), said retaining means (9, 9') being actuated by permitting the ingot or ingots (6, 6', 6'') to descend when the table (2) is in the tilted position (2'), the feeding device comprising, for each ingot (6, 6', 6'') supported by the table (2, 2'), a receptacle (21) which is movable between two positions, an inactive position (21'), in which it is located in the bath of melted zinc (4), and an operating position (21), in which it comes to be located below the lower edge (7') of the table (2') when this in the tilted position, in such a manner as to receive the upper end of the ingot (8, 8', 8'') when this end is released by said retaining means (9, 9').
4. Feeding device according to Claim 3, characterised in that the receptacle (21, 21') is displaced in translation parallel to the table (2, 2') when this is in the tilted position (2').
5. Feeding device according to Claim 4, characterised in that the receptacle (21) comprises a guide (22) which slides along the table (2, 2') when this is in the tilted position (2') and supports, at its lower end, a basket (23) disposed out of perpendicular on said sliding guide in such a manner as to come, in the operating position, below the lower edge (7') of the table (2') when this is in the tilted position.
6. Feeding device according to Claim 5, characterised in that the sliding guide (22) comprises a slide (24) consisting of a profiled section in the form of an inverse U comprising inner edges and a sliding piece (25) consisting of a profiled section in the form of an I, and in that said sliding piece (25) is connected by a chain (26) to a motor (27) comprising chain sprockets and a pneumatic or electric back-geared motor.
7. Feeding device according to Claim 4, characterised in that the receptacle (21) comprises a sliding guide located under the table (2) when this is in tilted position (2'), and supports as its lower end, a basket, which, in the operating position, comes to be located under the lower edge (7') of the table (2').

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