EP0922117B1 - Device for coupling a blow lance with a header - Google Patents

Abstract

A device for coupling a blow lance with a header is disclosed, in which the force required for producing a sealing joint between the header (2) and the lance (4) is exerted by a cooling fluid and/or a blowing fluid. In a preferred embodiment, said cooling fluid and/or blowing fluid acts via a pressure surface (32) on the joint between the header (2) and the lance (4), the pressure surface being integral with a piston (22) which transmits the pressure to said joint. The lance has preferably a first coupling surface (12), while the header (2) has a second coupling surface (14), and one of said coupling surfaces (12 or 14) is integral with said piston (22).

Description

The present invention relates to a device for coupling a lance metallurgical blowing to a manifold.

The blowing lances are used for example for the conversion of cast iron in steel by blowing oxygen on the metal bath in a converter. To avoid early damage to the lances due to temperatures high in the converter, the blowing lances are generally cooled with a coolant, for example water, which circulates in a cooling circuit. To this end, a lance comprises in general two annular chambers which are arranged coaxially around the oxygen channel of the lance and connected in the region of the lance nose so forming an annular supply and return channel for the fluid cooling. It follows that during its operation, such a lance must be connected to at least three pipes carrying the coolants and blowing.

The blowing lances must be changed due to wear after a fixed duration of use. For quick and easy replacement of a lance damaged by a new lance, many devices have been proposed to partially automate the connection of the lance to the pipes necessary for its operation, i.e. to allow connection concomitant of all the necessary conducts. Such devices include a coupling head with a first coupling surface and a clamping device for sealingly pressing the first surface coupling on a second coupling surface of the lance. The head coupling comprises several coaxial channels, the first end of which is connected to one of the pipes carrying the coolants and blowing and the second end of which opens into the first surface coupling. Similarly, the coaxial channels of the lance open in the second mating surface, so that after establishment tight contact between the two elements by means of the tightening a transfer of fluids is made possible at the head-lance junction.

Document DE-A-2512 487 therefore proposes a coupling device in which the lance is suspended from the coupling head and fixed to it using two clamping bolts and attached nuts. The bolts are mounted on the level of the coupling head so as to tilt laterally and are engaged in two notches with a flange secured to the lance. Strength necessary for the tight connection between the two mating surfaces is then established by tightening the two nuts.

This device, although very simple and compact, nevertheless presents some disadvantages. Indeed, changing the lance requires on the one hand manual work, such as loosening and tightening the bolts manually, which implies a risk of accident taking into account the environment in which these works are located and on the other hand, the fixed nature of the sealing manner, i.e. direct clamping of the two mating surfaces, installation a problem with sudden changes in coolant pressure and blowing. Such variations that occur for example in transient regime in the form of water hammer spread through the cooling system and can cause a temporary interruption sealing at the joint between the coupling head and the lance. A remedy for such a break would be to tighten the nuts further so increase the contact force of the two mating surfaces. However the clamping force of the two mating surfaces cannot be increased indefinitely so as not to destroy the sealing surfaces of the surfaces coupling.

The object of the present invention is to provide a coupling device for a blowing lance, allowing to dynamically adapt the force of pressure between the manifold and the lance as a function of pressure variations in cooling and / or blowing fluids.

According to the invention, this objective is achieved by a coupling device from a blowing lance to a collector, in which the force necessary to a tight junction between the collector and the lance is exerted by the fluid of cooling and / or blowing fluid. In such a device, the strength of pressure between the lance and the collector is not fixedly exerted by a conventional clamping means but it is exerted dynamically by one of the fluids necessary for the operation of the lance. This makes the pressure force between the collector and the lance varies according to the pressure of the fluid in question. As a result, abrupt variations in fluid pressures can be dynamically compensated so that even very violent water hammer does not lead to a risk of rupture of the system seal. In addition, no adjustment of the strength of tightening of the clamping means is not required when using the device to high speed, i.e. at high fluid pressures. Indeed, the adaptation dynamics of the support force of the two mating surfaces increases the pressure force automatically as soon as the pressure of the fluids increases and thus retains a pre-established basic seal with a some safety margin.

In a preferred embodiment, said cooling fluid and / or blowing acts via a pressure surface on the junction between the collector and the lance. It is known that the pressure force between the collector and the lance is proportional to the pressure of the fluid and to the surface area of pressure. It is obvious that we are talking here about the effective area of the pressure surface. The value of the pressure force for a certain fluid pressure can therefore be predetermined by the dimensioning of said pressure surface.

The pressure surface is, for example, integral with a piston which transmits the force of pressure at said junction. Preferably, the lance presents a first mating surface, the manifold has a second mating surface and one of said two mating surfaces is integral with said piston and opposite the pressure surface. The piston can also constitute part of the lance as the collector. It includes one of the two surfaces required for the connection and tightens it tightly against the other of said two mating surfaces.

In a preferred embodiment, the piston is embedded in a recess of the manifold so as to delimit by said pressure surface a pressure at the bottom of said recess. In this way, the pressure chamber can be connected directly to the fluid supply line cooling and / or blowing. Integrating the piston into the manifold also reduces investment costs since a refining unit includes several lances for a single collector.

Advantageously, the piston is executed in such a way that said force of pressure exerted by said piston is greater than the reaction force acting on the junction plane between said manifold and said lance. In this case difference between the seal obtained by the pressure force and the seal necessary, which constitutes the safety margin, increases progressively as the pressure of the cooling and / or blowing fluid increases.

A preferred embodiment of the invention consists of a coupling device from a blowing lance to a manifold which is connected to pipes carrying blowing and cooling fluids, the lance comprising first channels for said fluids which extend through said lance and which open at one end into a first surface coupling, the manifold comprising second channels for said fluids, each of said second channels being associated with one of said first channels, being in connection with one of said conduits and opening out to a end in a second mating surface, said second surface of coupling being associated with said first coupling surface and which can be pressed against it by means of a clamping means so forming a tight junction between said first and second channels associated. Said manifold comprises a coupling head and said second mating surface is integral with a piston which is embedded in a axial recess of said coupling block so as to delimit by a surface pressure chamber a pressure chamber at the bottom of said recess, said surface pressure of the piston being opposite the second coupling surface. A supply line is connected to said pressure chamber so that the fluid supplied by said supply line exerts pressure on said pressure surface and therefore the piston exerts a pressing force on said first coupling surface.

In this device, only part of the supporting force necessary for the tight connection between the coupling head and the lance is exerted by a conventional clamping means, that is to say in a fixed manner. It's about a certain basic pressing force which guarantees the minimum required tightness. During refining, the pressure of the fluid supplied by the connecting pipe with the pressure chamber, preferably the coolant, exerts pressure on the pressure surface of the piston and therefore the piston exerts a pressing force on the first mating surface of the launch. Due to the effective pressure surfaces for fluids and the pressure drop in the cooling system between the supply line and the return line, this pressing force is greater or equal to the reaction force exerted on the junction between the coupling head and launches it. This results in an increase in the bearing force of the two surfaces coupling and therefore the sealing of the coupling. As described above, this device makes it possible to dynamically compensate for sudden variations in fluid pressures and adapt automatically at high speed, i.e. at high fluid pressures, while retaining a safety margin in the form of minimum sealing required established by the clamping means.

In a preferred embodiment of the invention, the device comprises means attachment to suspend the lance to said coupling head. Said hooking means, eg hooks which are mounted pivotally on said coupling head and which can engage journals extending radially from said lance. In an other execution, said attachment means comprise locking rods which are pivotally mounted on said coupling head as well as a radial flange on said lance on the side of the first coupling surface, said radial flange having radial notches intended to receive the locking rods so that the heads of said locking rods take support on the side of said flange which is opposite the first surface coupling. These two executions of fastening means eliminate the the need for manual work such as tightening and loosening nuts. The attachment is faster and poses less risk to the staff. Fixing with locking rods is particularly advantageous because it makes it possible to minimize the piston stroke. In indeed, to replace a hanging lance, the lance must be moved certain distance towards the coupling head until the heads blocking rods can pass the lower edge of said flange in order to be spread laterally. As the piston rests on the lance, it must also be moved the same distance, which should be done if necessary against the action of the clamping means. It is therefore advisable to limit the distance of movement to limit the work to be done to move the piston by example against the action of the clamping means or its weight.

Said clamping means preferably comprises springs which are arranged between the coupling head and said piston, said springs being prestressed when attaching the lance to the coupling head.

In order to facilitate the centering of said two coupling surfaces, one of said two mating surfaces advantageously comprises an edge axially projecting annular extending, said annular edge having a inner diameter which is substantially equal to the outer diameter of the other said coupling surfaces.

A little further on, a preferred embodiment of the invention is described using in Figure 1 which shows a vertical cross section of a coupling for blowing lances. It includes a coupling head 2 which is connected to cooling and blowing fluid lines (not shown) on which a blowing lance 4 is hung. The lance 4 comprises a central channel 6 for a blowing gas, eg oxygen, which is coaxially surrounded by two chambers 8, 10 with annular sections. Both chambers 8 and 10 are connected in the region of the lance nose 4 (not shown) so as to form a supply channel 8 and a return channel 10 to annular sections for the coolant. Note that the spear could include additional channels for other blowing gases. These channels would then be located coaxially between the central channel and the cooling system channels.

On the coupling end of the lance 4, the channels 6, 8 and 10 open out in a first mating surface 12 which is associated with a second coupling surface 14 of the coupling head 2. In said first mating surface 12, channels 6, 8 and 10 then form mouths coaxial annulars which are separated radially by the front faces annular tubular walls 16, 18 and 20 of the different channels. The walls 16, 18 and 20 are reinforced in the region of the first mating surface 12 and their front faces are executed in the form of surfaces sealing.

In order to allow a transfer of the cooling and blowing fluids from the coupling head 2 towards the lance 4, the first coupling surface 12 must be pressed tightly against the second mating surface 14 and a connection between channels 6, 8 and 10 and the pipes carrying the respective cooling and blowing fluids must be established.

To do this, the coupling head 2 advantageously comprises a piston 22 which is mounted axially sliding in a recess 24 of the coupling head 2 and can establish tight contact with the first coupling surface 12 under the action of a clamping means 25. This piston 22 then has the second coupling surface 14 on its end oriented towards lance 4 and includes channels 26, 28 and 30 for fluids cooling and blowing which are assigned to channels 6, 8 and 10 of the lance 4. One end of each channel 26, 28 and 30 opens out in such a way way in the second mating surface 14 that the mouths of the channels 6, 8 and 10 in the first mating surface 12 and the mouths respective channels 26, 28 and 30 in the second coupling surface 14 are superimposed exactly during mating. In this case, the mouths of channels 26, 28 and 30 in the second coupling surface 14 are separated, similarly to the mouths of channels 6, 8 and 10 in the first mating surface 12, by front faces annular tubular walls separating the different channels 26, 28 and 30. These annular front faces are then also executed in the form of sealing surfaces and, during coupling, bear on the faces respective annular front faces in the first mating surface 12.

The clamping means 25 which presses the second coupling surface 14 of the piston 22 against the first mating surface 12 of the lance comprises preferably springs which are arranged in a groove on the surface front of the coupling head 2 and bear against a radial projection 27 piston. These springs 25 are then prestressed during the coupling of the lance 4 and thus exert a force on the piston 22 in the direction of the lance 4. It it is obvious that any other tightening means would be suitable for pressing the piston 22 against lance 4, eg hydraulic cylinders, actuated worms by any motor, etc. or a combination of these.

On its end opposite to the second coupling surface 14, the piston 22 has a pressure surface 32 through which it delimits a pressure 34 in the bottom of the recess 24. Through this pressure chamber 34, which in the example shown is connected to the supply line in coolant through a connecting pipe 36, the lance 4 is supplied with cooling fluid. To this end, channel 28 of coolant supply opens into the surface of pressure 32 so as to be in connection with the pressure chamber 34. The channel 30 for return of the cooling fluid advantageously opens in an annular chamber 38, delimited by a circumferential groove 40 in the piston and the side wall of the recess 24. This annular chamber 38 is then connected to a connection pipe to the return line of the cooling fluid 42. It should be noted that the axial dimension of the groove circumferential 40 is greater than the axial dimension of the mouth of the drain hose 42 so that the mouth of drain hose 42 is not blocked by the lateral surface of the piston during the axial displacement of this one.

The channel 26 of the blowing fluid opens into the pressure surface 32 of the piston 22 and is extended tightly through the pressure chamber 34 via a tube 44, one end of which is embedded so sliding and sealed in said channel 26 and the other end of which extends through the bottom of the recess 24 to exit at the top of the coupling head 2, where it ends in a connecting pipe 46 to the fluid line blowing. It should be noted that the junction between the tube 44 and the channel 26 is made waterproof using several annular seals 48 arranged around the end embedded in the tube 44. Similarly, the pressure chamber 34 and the chamber ring 38 are sealed using O-rings which are arranged eg in circumferential grooves of piston 22. An alternative design for connection of channel 26 to the respective supply line consists in extending the channel 26 beyond the pressure surface 32 so that it passes through the pressure chamber 34 and extends through a bore in the bottom of the recess 24 to exit at the top of the coupling head 2. In this in this case the channel 26 is guided through the bore in the bottom of the recess of watertight and axially sliding. Outside the coupling head 2, the channel 26 can then be connected to the gas supply pipe for blowing through a flexible compensator, which allows a tight connection and able to adapt to the axial displacements of the channel 26.

To couple a lance 4 to this coupling device, the lance is brought by a bridge or an ad hoc manipulator which positions it with its surface coupling 12 below the coupling surface 14 of the head coupling 2 so that the axes of the lance 4 and the coupling head 2 are aligned. Under the action of its weight resp. clamping means 25, the piston 22 and therefore the second coupling surface 14 is are now in their lowest position relative to the head coupling 2. The lance 4 is then lifted until the two mating surfaces 12 and 14 come into contact. To facilitate centering of the two mating surfaces 12 and 14, one of the two surfaces (in the fig.1 the first mating surface 12) includes an annular edge 48 which extends axially and has an inner diameter which is substantially equal to the outside diameter of the other of said coupling surfaces 14.

After establishing contact between the two mating surfaces, the lance 4 is raised further and the piston 22 is moved against the action of the springs 25. It should be noted that the weight of the collector and its equipment device here acts as a counterforce, so the springs 25 can be prestressed with a force substantially equivalent to this weight. The lance 4 is then advantageously hooked by two locking rods 50 which are mounted on either side of the coupling head 2 and are received by two notches 52 of a radial flange 54 of the lance 4, so that the heads 56 of the locking rods 50 bear on the lower surface of the flange 54. In order to be able to remove the lance 4, the locking rods 50 are mounted on the coupling head 2 pivotally so that their heads 56 can be moved laterally (as indicated on the fig.).

In this way, a "basic" coupling is achieved under the action of springs 25 which has a minimum seal necessary to start the coolant supply. When supplying cooling, the coolant pressure exerts a pressure on the pressure surface 32 of the piston 22 and consequently the piston 22 exerts a pressing force on the first coupling surface 12 of the lance 4. It will be obvious to those skilled in the art to size the piston 22 of in such a way that due to the effective pressure surfaces for the fluids and the pressure drop in the cooling system between the pipe supply and return line, the pressure force exerted by the piston is greater than or equal to the reaction force exerted on the junction between the coupling head and the lance. In this case, it results in a increase in the support force of the two mating surfaces and by consequently of the sealing of the coupling. This device therefore makes it possible to dynamically compensate for sudden changes in pressure from fluids and automatically adapt to a high regime.

It should also be noted that the piston may as well be subjected to pressure blowing gas only at coolant pressure.

Claims (12)

1. Device for coupling a blowing lance to a collector, characterised in that the force necessary for an impervious junction between the collector (2) and the lance (4) is exerted by a cooling fluid and/or a blowing fluid.
2. Coupling device according to Claim 1, characterised in that the said cooling fluid and/or the blowing fluid acts through the intermediary of a pressure surface (32) on the junction between the collector (2) and the lance (4).
3. Coupling device according to Claim 2, characterised in that the pressure surface (32) is an integral part of a piston (22) which transmits the pressure force to the said junction.
4. Coupling device according to Claim 3, characterised in that the lance (4) has a first coupling surface (12), in that the collector (2) has a second coupling surface (14), and in that one of the two coupling surfaces (12 or 14) is an integral part of the said piston (22).
5. Coupling device according to Claim 3 or 4, characterised in that the piston (22) is embedded in a recess (24) in the collector, so that the said pressure surface (32) defines a pressure chamber (34) at the bottom of the said recess (24).
6. Device according to one of Claims 3 to 5, characterised in that the piston (22) is made in such a way that the said pressure force exerted by the said piston (22) is greater than the reaction force acting on the plane of the junction between the said collector (2) and the lance (4).
7. Device for coupling a blowing lance to a collector which is connected to ducts carrying blowing and cooling fluids, the lance (4) comprising first channels (6, 8, 10) for the said fluids which extend through the said lance (4) and which open at one end into a first coupling surface (12), the collector comprising second channels (26, 28, 30) for the said fluids, each of the said second channels (26, 28, 30) being associated with one of the said first channels (6, 8, 10), being connected to one of the said ducts and opening at one end into a second coupling surface (14), the said second coupling surface (14) being associated with the said first coupling surface (12) and being capable of being pressed against the latter using a clamping means (25) so as to form an impervious junction between the said first (6, 8, 10) and second (26, 28, 30) associated channels, characterised in that the said collector comprises a coupling head (2), in that the second coupling surface (14) is an integral part of a piston (22), which is embedded in an axial recess (24) in the said coupling head (2) so that a pressure surface (32) defines a pressure chamber (34) at the bottom of the said recess (24), the said pressure surface (24) of the piston (22) being opposite the second coupling surface (14), and in that a supply duct is connected with the said pressure chamber (34) in such a way that the fluid supplied through the said supply duct exerts a pressure on the said pressure surface (32) and so that the piston (22) exerts a pressure force on the said first coupling surface (12).
8. Device according to Claim 7, characterised by coupling means to suspend the lance (4) from the said coupling head (2).
9. Device according to Claim 8, characterised in that the coupling means comprise hooks which are mounted so that they pivot on the said coupling head and which may engage with trunnions extending radially from the said lance (4).
10. Device according to Claim 8, characterised in that the coupling means comprise locking rods (50) which are mounted so that they pivot on the said coupling head (2) and a radial flange (54) on the said lance (4) on the side of the first coupling surface (12), the said radial flange (54) having radial notches (52) designed to receive the locking rods (50) so that the heads (56) of the said locking rods (50) bear on the side of the said flange (54) which is opposite the first coupling surface (12).
11. Device according to one of Claims 7 to 10, characterised in that the said clamping means (25) comprise springs which are positioned between the coupling head (2) and the said piston (22), the said springs being prestressed during the coupling of the lance (4) to the coupling head (2).
12. Device according to one of Claims 7 to 11, characterised in that one of the said two coupling surfaces (12 or 14) comprises a protruding annular edge (48) extending axially, the said annular edge (48) having an inner diameter which is roughly equal to the outer diameter of the other of the said coupling surfaces (14 or 12).

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