FR2763079A1 - Rotor and installation for the treatment of a bath of liquid metal - Google Patents

Abstract

A rotor is claimed for the treatment of a bath (3) of liquid metal, notably for the injection of a treatment gas, and for mechanical agitation, of the type comprising a hollow shaft (5)with a gas feed channel (8) and a stirring head (7) incorporating at least one blade or fin and some means for injecting gas connected to the feed channel (8). The hollow shaft (5) and the stirring head (7) are made from a refractory impervious to the treatment gas. The means of injection are made up of at least one conduit (11) cut in the stirring head (7), connected to the feed channel (8) and closed with a diffusion plug (13) in a refractory material porous to the treatment gas, in order to ensure an injection of gas in the form of very fine bubbles. An installation utilising this rotor for the treatment of liquid metal in a bath is also claimed.

Description

 The present invention relates to metallurgy and, more particularly, to the field of treatment of liquid metal baths by stirring and dispersion of a gas in the bath, with a view to eliminating, by coalescence, flocculation or chemical suppression, solid impurities or gas contained in the molten metal.

 Thus, for example, in the context of the metallurgy of aluminum and its alloys, it is necessary to treat the molten metal before its shaping, to remove both the hydrogen dissolved in the metal and the oxides which create by reaction with the surrounding atmosphere. Indeed, these impurities are capable of generating, during the solidification of the metal, inclusions and pitting detrimental to the aesthetic and mechanical qualities of the parts produced.

 To ensure the elimination of these impurities, it is known to inject, within the liquid metal bath, a neutral or reactive gas via a rotor.

 Application EP 0 332 292 describes a gas dispersion installation for the treatment of a bath of liquid metal, which comprises a rotor immersed in the bath, supplied with gas and driven in rotation by a geared motor. The rotor has a hollow axis, made of refractory material, such as graphite, which defines a supply channel. The hollow axis carries, at its end intended to be immersed in the bath of liquid metal, a cylindrical mixing head, also made of graphite. This brewing head has a central chamber open to the metal in its lower part and communicating, on the one hand with the hollow shaft via an opening of small diameter and, on the other hand, with several compartments open to the peripheral surface of the head.

 The implementation of this installation is carried out by supplying the rotor with treatment gas, such as, for example, nitrogen or a mixture of the latter with chlorine and by rotating the rotor. In order to ensure a fine and homogeneous dispersion of the gas in the liquid bath, it is necessary that the stirring head is of a sufficient diameter, typically close to 200 mm, and that it is driven at speeds of between 300 and 600 rpm. Indeed, the production of fine bubbles, ensuring intimate contact between the metal to be treated and the treatment gas, is only possible through the effect of centrifugal force which sucks the metal into the central chamber, then rejects the mixture. gas / metal in the bath through the peripheral compartments.

 Such an installation makes it possible to ensure the treatment of a bath of liquid metal effectively. However, the speed of rotation, required to ensure the centrifugation of the metal and therefore a fixed dispersion of the gas, requires the use of a high power gearmotor, typically close to 1,500 watts, as well as the maintenance of the shaft. hollow by a perfectly balanced rigid apparatus, which makes the treatment installation bulky and difficult to move.

 Application FR 2 512 067 describes an installation in which the mixing head comprises radial vanes and a series of pairs of channels, each pair comprising a channel for the passage of the liquid and the other for the passage of the gas, each of the pairs emerging separately at the same point from the peripheral surface of the head. The production of fine bubbles is, in this installation, also dependent on the centrifugal force exerted by the rotation of the brewing head and due to a shearing effect by the peripheral fins.

 The diameter of the brewing head, currently close to 250 mm, and the required speed of rotation, varying between 300 and 600 rpm, allow effective treatment of the metal, within, however, a powerful installation and heavy, therefore difficult to handle.

 Thus, the treatment installation according to application FR 2 512 067 is mainly usable at a fixed station for the treatment of a bath of liquid metal in a continuous production installation. On the other hand, this treatment installation is ill-suited to intermittent use for the treatment of liquid metal baths in transport bags or for the successive treatment of several baths in different places. In fact, in the context of such use, it is necessary to move either the metal bath to position it under a handling system of the treatment installation, or the installation itself to place it in relationship with the bath to be treated. However, these different movements can only be carried out by means of machines or handling systems which make the operation delicate and relatively long.

 It therefore appears necessary to have a light installation which is easily movable and usable by a single operator to ensure the successive treatment of baths of liquid metal contained in refractory bags or containers distant from each other without the use of heavy and bulky handling means. In addition, it is necessary that such an installation can be easily moved over a more or less uneven surface in a more or less congested space.

 The applicant had the merit of highlighting that it was not possible to achieve the desired result by using rotors of the type of those of applications EP 0 332 292 and FR 2 512 067, taking into account the power necessary to set them in motion at sufficiently high speeds to obtain a reasonable treatment efficiency.

 Another drawback, to be taken into account of the rotational speeds imposed on the rotor, is rapid wear or erosion of the rotor, resulting from friction in the liquid metal, so that a reduction in the rotational speed would contribute, in an additional way , to increase the longevity of the rotor.

 Application FR 2 628 756 has suggested producing a rotor for the injection of a treatment gas into a bath of liquid metal and for the mechanical agitation of the latter, comprising a hollow shaft equipped at its end with a brewing head provided with fins and made of porous graphite with treatment gas. Such a constitution of the brewing head seems to allow a reduction in the speed of rotation of the rotor which is then between, approximately, 200 to 300 rpm.

 However, the implementation of the rotor thus formed is not entirely satisfactory for several reasons. First of all, contrary to what might be envisaged a priori, the use of a porous head does not make it possible to obtain a uniform diffusion of the treatment gas inside the bath of liquid metal. Indeed, when the rotor is driven in a rotational movement inside the bath, it creates, around the brewing head, more or less high pressure areas, the distribution of which is not controllable. Given the existence of these localized pressure differences, the diffusion of the gas does not take place through the entire peripheral surface of the head, but only through preferential diffusion zones, located at the regions of least pressure. surrounding said head.

 To this inefficiency linked to the dynamic behavior of the rotor, it is also necessary to add another drawback linked to the very porous structure of the head which makes it less resistant to wear or erosion resulting from friction against the metal in question. fusion. Furthermore, the rotor, with a porous stirring head, does not allow the speed of rotation to be reduced sufficiently to allow the use of motor means of a power significantly lower than that of the motor means used by the installations described above.

 There therefore appears to be a need for a new rotor which can be implemented with low power motor means, in particular by a significant reduction in its weight, its diameter and its speed of rotation, while offering efficiency. sufficient for the proper treatment of a liquid metal bath.

 To achieve the above objectives, the invention relates to a new rotor for the treatment of a bath of liquid metal, in particular by injection of a treatment gas and by mechanical agitation, of the type comprising a hollow shaft which defines a gas supply channel and which has, at its end intended to be immersed in the bath, a stirring head comprising at least one blade or fin and gas injection means connected to the supply channel.

According to the invention, this new rotor is characterized in that
- the hollow shaft and the brewing head are made of refractory material
gas-tight,
- and the injection means consist of at least one conduit
formed in the brewing head, connected to the supply channel and
closed by a diffuser cap made of a porous refractory material to gas
treatment, to ensure, in the bath, an injection of gas under the
form of very fine bubbles.

The invention also relates to an installation for the treatment of a bath of liquid metal, in particular by injection of a treatment gas and by mechanical agitation. This installation comprises - a rotor according to the invention, - a support which is provided with means for fixing and guiding the rotor in rotation
and which allows the rotor to be placed in the bath, - means for driving the rotor in rotation, in relation to means
engines, - means for supplying the rotor with treatment gas, - means for controlling the supply of gas and the rotation of the
rotor.

 Surprisingly, it emerged from tests that the rotor according to the invention had a higher efficiency than that of the rotors known from the prior art. Thus, to obtain processing conditions and results equivalent to those of the previous rotors, it is possible, with the new rotor, to adopt lower rotational speeds and / or dimensions.

 The drive means of a treatment installation implementing a rotor according to the invention can therefore have a power lower than that of the drive means necessary for the rotors according to the prior art. In the same direction, setting in motion the new rotor implies the transmission of a less significant torque than for the previous rotors.

 Given the characteristics of the new rotor, it appeared possible to meet the needs already mentioned for a relatively light mobile treatment installation, having a small footprint so that it can be easily moved over a more or less equal surface in a more or less space. crowded.

To achieve this objective and according to an alternative embodiment, the treatment installation according to the invention is characterized in that:
- the support consists of a frame intended to be handled by a
operator to be placed above and removed from the bath to be treated,
- the drive means consist of a flexible cable
contained in a sheath and connected, on the one hand, to the means of
guiding and fixing the rotor and, on the other hand, to motor means
carried by a cart,
the supply means comprise a source of
adapted treatment on the trolley and connected by a pipe
flexible and at least one rotating joint system, at the channel
rotor supply,
- And the carriage is equipped with control means and means of
transport of the frame to allow easy movement of the assembly
installation by the operator.

 Preferably, the carriage is made in the form of a hand truck.

 Various other characteristics will emerge from the description given below with reference to the appended drawings which show, by way of nonlimiting examples, embodiments of the subject of the invention.

 Fig. 1 shows a schematic overview of a preferred embodiment of an installation using a rotor according to the invention.

 Fig. 2 is a section along the line II-II of FIG. 1, a rotor mixing head.

 Fig. 3 is a partial top view of the installation along the line m-m delafig. 1.

 Figs. 4 to 8 are axial sections showing different embodiments of a stirring head of a rotor according to the invention.

 The preparation of a charge of liquid metal, for later use, such as shaping by molding or injection for example, consists, in the context of the invention, in particular in injecting a treatment gas into the metal in and mechanically agitating the latter to remove solid or gaseous impurities.

 Generally and as shown in FIG. 1, the installation, designated as a whole by the reference 1, to ensure such treatment comprises a rotor or agitator 2 immersed in a bath 3 of liquid metal, such as for example aluminum or an alloy thereof melted, contained in a container or a pocket 4 of refractory material. Of course, the installation 1 could be used for the treatment of any other metal or alloy in the category, for example, but not exclusively, non-ferrous alloys.

 The rotor 2 has a hollow shaft 5, fixed by a first end to means 6 for guiding and driving, and provided, at its other end immersed in the bath 3, with a stirring head 7. The hollow shaft 5 defines a through feed channel 8 whose function will appear later. The stirring head 7, attached to the end of the shaft 5, has a body 9 of substantially cylindrical shape, provided with at least one, and according to the example illustrated, three fins or blades 10 extending radially to the periphery of the body 9, as shown in FIG. 2. In accordance with the purpose of the rotor 2, the stirring head 7 also has means for injecting a treatment gas into the bath 3, connected to the supply channel 8. According to the example illustrated, these injection means are constituted by a conduit 11 coaxial with the channel 8, connected to the latter to lead to the lower face 12 of the stirring head 7, opposite the shaft 5.

Finally, in accordance with an essential characteristic of the invention, the conduit 11 is closed at the face 12, opposite the shaft S, by a porous diffuser plug 13 which is permeable to the treatment gases to be injected into the bath 3 of liquid metal. Preferably, the diffuser plug 13 is removable and adapted on the head 7, for example by means of a thread formed at the periphery of the plug 13 and cooperating with a complementary thread made in the wall of the duct 11.

Similarly, the head 7 is fitted to the hollow shaft 5, by a substantially identical device. The fixing threads of the head 7 and of the plug 13 preferably have an orientation such that, when the rotor 2 is in movement, this movement tends to tighten the head 7 and the plug 13, respectively, on the shaft 5 and on the head 7. Of course, the plug 13 and the stirring head 7 could be fixed in a completely different way, for example by gluing.

 The shaft S and the stirring head 7 are made of refractory material, impermeable to the treatment gases and of a nature suitable for that of the said gas and of the bath 3 to resist chemical attack and mechanical erosion resulting from the friction of the rotor 2 in liquid metal. In the context of the treatment of an aluminum bath or an alloy of this metal for example, the shaft S and the head 7 can be made of graphite, silicon carbide, refractory ceramic material or the like.

 The diffuser plug 13 is also made of refractory material adapted to the nature of the treatment gas and that of the bath of liquid metal. However, unlike the shaft S and the stirring head 7, the diffuser plug 13 has a porous nature, permeable to the treatment gas to be injected into the bath 3. Of course, the material constituting the plug 13 must be compatible with that of the stirring head 7. Thus, preferably, the plug 13 is made of the same material as that constituting the other elements of the rotor 2, such as, for example, graphite, silicon carbide, a refractory ceramic material or the like all having a porous structure permeable to the treatment gas.

 The means 6 for fixing and guiding the rotor 2 in rotation are, for example, constituted by a hollow sleeve 15, in which is engaged the end of the shaft S opposite the head 7. This sleeve 15 is held and guided in rotation by a system 16 of bearing and thrust ball or roller. The means 6 for fixing and guiding are integral with a support 20 which makes it possible to maintain the rotor 2 inside the bath 3. According to the example illustrated and as is more particularly apparent from FIG. 3, the support 20 is constituted by a frame comprising two cross members 21 arranged in a "T" and provided, at their ends, with adjustable feet 22 to come to bear on the edge of the pocket 4. The frame 20 also has a handle 23 to allow the handling, by an operator, of the assembly which it constitutes with the rotor 2.

 To ensure the rotation of the rotor 2, the treatment installation 1 also includes drive means in relation to motor means. Preferably, the drive means consist of a flexible cable 25, contained in a protective sheath 26 and connected to the means 6 for fixing and guiding and, more particularly, to the sleeve 15. The cable 25 then ensures the connection between the sleeve 15 and motor means 27, such as, for example, an electric gear motor, a pneumatic motor or the like. The motor means 27 are preferably, but not exclusively, adapted on a mobile carriage 28. According to the example illustrated, the mobile carriage 28 forms a trolley and comprises a frame formed by two uprights 29. This frame has, on the one hand , at its base and in front of an axle 30 carrying two wheels 31, a platform 32 forming a crutch and, on the other hand, opposite the platform 32, a handlebar or carrying handles 33. The drive means 27 are then fixed to the uprights 29 of the devil 28.

 The installation 1 also includes means for supplying treatment gas to the rotor 2. These supply means comprise a source of treatment gas 34 fitted to the carriage 28 and connected by a connector 35 to the sheath 26 which is made of material compatible with and impervious to the treatment gas. The sheath 26 then performs a function of flexible supply pipe to the rotor 2.

Of course, the supply of the channel 8 could be carried out by a flexible pipe, independent and distinct from the sheath 26. At its end opposite to the carriage 28, the sheath 26 is connected, by a system of rotating joint 36, to the means 6 of supports and guiding the rotor 2, so as to communicate with the supply channel 8.

 Finally, the devil 28 carries control means 37 ensuring the control of the operation of the motor means 27, as well as the supply of treatment gas. The control means 37 include, for example but not exclusively, a regulator system and flow control valves, connected, on the one hand, to the gas source 34 by a line 39 and, on the other hand, to the connection 35 by a line 40. The control means 37 are also connected to the motor means 27 by a line 41.

 The installation 1 described above is implemented in the following manner.

 After having ordered the gas supply to the rotor 2, an operator places the support 20 on the pocket 4, so as to immerse the rotor 2, and more particularly the stirring head 7 in the liquid metal bath 3. Taking into account the particularly light character of the assembly constituted by the support 20 and the rotor 2, the operator can carry out this positioning alone, without the assistance of handling means.

 Once the rotor 2 is immersed in the liquid metal, the operator controls the starting of the motor means 27 which, via the cable 25 and the fixing and guiding means 6, drive the rotor 2 in rotation, so that the metal of bath 3 is stirred. Simultaneously, the plug 13, supplied via the channel 8, diffuses, in the form of very fine bubbles, the treatment gas inside the bath. When starting the motor means 27, the cable 25 advantageously fulfills a torque damper function, so that the rotation of the rotor 2 is carried out smoothly. In addition, given the high efficiency of the rotor 2 according to the invention, it is possible to adopt a relatively low speed of rotation, between 100 and 250 rpm and, preferably, close to 200 rpm. min. Such a speed allows the use of low power motor means, having a small footprint, which contributes to the mobility of the installation 1. Similarly, setting the rotor 2 in motion requires the transmission of a low torque which can then be effectively ensured by the flexible cable 25.

In addition, the adoption of a low speed makes it possible to increase the life of the rotor 2 by reducing the friction of the latter against the molten liquid metal.

 In order to avoid the appearance of a vortex phenomenon within the bath 3, the support 20 can be equipped with a deflector 43 plunging into the liquid metal.

 At the end of treatment, the motor means are stopped, then, after extraction of the rotor 2 from the bath 3, the gas injection is interrupted. The operator can then place the mobile assembly, constituted by the support 20 and the rotor 2, on transport means equipping the hand truck 28. These transport means are, for example, formed by a bracket 45 fixed to the uprights 29. The treatment installation according to the invention thus forms a compact unit, entirely carried by the hand truck 28 which can be easily moved close to another pocket located at a distance from the one whose bath 3 has been treated.

 In the example illustrated above, the diffuser plug 13 is flush with the underside of the stirring head 7. FIG. 4 illustrates another alternative embodiment of the rotor 2 which differs from that illustrated in FIG. 1 in that the diffusing plug 13 projects under the head 7 at the level of the lower face 12. According to this example, the diffusing plug 13 has a hollow internal structure, defining a chamber 131 communicating with the conduit 11.

 As shown in fig. 5, the lower face 12 of the stirring head 7 may comprise, opposite the shaft 5, a flange 46 having radial peripheral openings 47 to define a kind of bell capable of trapping one or more pellets of solid flux introduced into bath 3 to ensure its chemical treatment. The implementation of the installation comprising a rotor according to this alternative embodiment is carried out as follows.

 Solid flux pellets, such as for example intended for the refining and / or the modification of the metal, are introduced into the bath 3. Taking into account a difference in density with the liquid metal, the flux pellets float at the surface of the bath. The bell, defined by the stirring head 7, is then used to trap said pellets during the introduction of the rotor 2 into the bath and to drive these pellets to the bottom of the bath to be treated. After the rotor 2 has rotated, the flow of the pellets diffuses, together with the treatment gas, inside the bath through the peripheral openings 47 of the rim 46.

 Fig. 6 illustrates another alternative embodiment of the rotor 2 which differs from that shown in relation to FIG. 4 in that it has means for supplying or injecting flux inside the bath of liquid metal.

 According to the example illustrated, these supply means consist of a pipe 50 disposed axially to the supply channel 8, to the conduit 11 and to the chamber 131 to pass through the diffuser plug 13 and open out on the side of the lower face 12 of the stirring head 7. The treatment installation 1 then comprises means for supplying flux in powder form, not shown. These flow supply means are, for example, constituted by a flow source adapted on the carriage 28 and connected to the supply pipe 50 of the rotor by a flexible tube and a rotating joint device.

 During the implementation of this installation, the axial position of the supply pipe to the core of the rotor, as well as the fact that its terminal part is surrounded by the plug 13, ensure good thermal insulation of the flow and thus avoid premature melting which would cause clogging of the supply line 50 and a malfunction of the installation.

 In the examples above, the means for injecting the treatment gas, equipping the rotor 2, consist of a pipe coaxial with the supply channel 8.

However, these injection means could be produced in any other suitable form insofar as, within the meaning of the invention, their outlet section within the bath of liquid metal is closed by at least one diffusing plug permeable to gas. treatment. The diffuser plug advantageously provides protection for the rotor preventing the liquid metal from rising inside the head 7 and the channel 8 in the event of a cessation of the supply of treatment gas or in the event of insufficiency. supply pressure.

 Fig. 7 illustrates another embodiment of the rotor 2 according to which the stirring head 7 defines, in relation to a base 51 of the shaft 5, an annular chamber 52 which opens at the periphery of the head 7 and which is connected to the channel supply 8 by a series of radial conduits 53. The annular chamber 52 is then closed at its periphery by a diffuser plug 13, also of annular shape.

 According to another embodiment of the rotor 2, more particularly illustrated in FIG. 8, the injection means consist of at least two, and according to example three, radial conduits 54 which are formed inside the blades 10 to open, on the one hand, at the periphery of the stirring head 7 and, on the other hand, in an internal chamber 55 connected to the supply channel 8. According to the invention, the outlet section of each conduit 54, at the periphery of the stirring head 7, is closed by a porous plug 13. Preferably, the outlet section of the conduits 54 is arranged to receive a porous plug 13 offering a contact surface with the bath of liquid metal greater than the nominal passage section of the radial conduits 54.

 In the above examples, the body 9 of the stirring head 7 has a substantially cylindrical shape. Of course, this body 9 could have any other suitable shape, such as, for example, with a polygonal cross section, in order to make its manufacture or machining easier.

 The rotor according to the invention is preferably intended to be used in the context of a mobile installation, as described in relation to FIGS. 1 to 3.

However, the rotor 2 could be implemented with any other type of installation, such as, for example, a fixed or mobile station installation intended to be transported by handling means, such as a bridge, a motorized stem or the like.

 The invention is not limited to the examples described and shown since various modifications can be made thereto without departing from its scope.

Claims (13)

CLAIMS:  gas in the form of very fine bubbles.  porous to the treatment gas, to ensure, in the bath, an injection  (8) and closed by a diffuser plug (13) made of refractory material  formed in the brewing head (7), connected to the supply channel  - And the injection means consist of at least one conduit (11)  refractory gas-tight treatment,  - the hollow shaft (5) and the stirring head (7) are made of material  characterized in that:  1- Rotor for the treatment of a bath (3) of liquid metal, in particular by injection of a treatment gas, and by mechanical agitation, of the type comprising a hollow shaft (5) which defines a channel (8) of gas supply and which has, at its end intended to be immersed in the bath, a stirring head (7) comprising at least one blade or fin and gas injection means connected to the supply channel,  2 - Rotor according to claim 1, characterized in that the injection means consist of a conduit (11) which opens on the underside (12) of the head (7), opposite the shaft ( 5), and which is closed by a removable diffuser cap.  3 - Rotor according to claim 1, characterized in that the injection means consist of a conduit forming an annular chamber (51) which opens at the periphery of the head, which is connected to the supply channel (8) and which is closed by an annular diffuser plug (13).  4 - Rotor according to claim 1, characterized in that the injection means consist of at least two radial conduits (54), each of these channels, opening at the periphery of the head (7), being connected to the channel d 'supply (8) and being closed by a diffuser plug (13).  5 - Rotor according to one of claims 1 to 4, characterized in that the lower face (12) of the head (7), opposite the shaft (5), has a flange (46) having peripheral openings (47) to define a sort of bell capable of trapping one or more pellets of solid flux introduced into the bath for its treatment.  6 - Rotor according to one of claims 1 to 4, characterized in that it has means for supplying flux inside the bath (3).  7 - Rotor according to claims 2 and 6, characterized in that the supply means are constituted by a supply pipe (50) which is arranged axially to the supply channel (8) and which passes through the diffuser plug (13 ) to open on the side of the lower face (12) of the head.  8 - Installation for the treatment of a liquid metal bath, in particular by injection of a treatment gas and by mechanical agitation, of the type comprising - a rotor (2) constituted by a hollow shaft (5) which defines a channel ( 8) feed  gas and which has, at its end intended to be immersed in the bath, a  brewing head (7) comprising at least one blade or fin (10) and means  for injecting gas into the bath (3) connected to the supply channel (8), - a support (20) which is provided with means (6) for fixing and guiding in rotation  of the rotor (2) and which makes it possible to place the rotor in the bath, - means for driving the rotor (2) in rotation, in relation to means  engines (27), - means for supplying the rotor (2) with process gas, - control means (37) for the supply of gas and the rotation  rotor,  characterized in that it implements a rotor (2) according to one of claims 1 to 7.  9 - Installation according to claim 8, characterized in that:  - the support (20) consists of a frame intended to be manipulated by  an operator to be placed above the bath to be treated and to be  took of,  - the drive means consist of a flexible cable (25)  contained in a sheath (26) and connected, on the one hand, to the means (6)  for guiding and fixing the rotor and, on the other hand, to means  motors (27) carried by a carriage (28),  the supply means comprise a source (34) of  adapted treatment on the carriage (28) and connected, by a  flexible pipe (26) and at least one system (36) of rotary joint,  to the supply channel (8) of the rotor (2),  - And the carriage (28) is equipped with control means (37) and  means of transport (45) of the frame to allow easy movement  of the entire installation by the operator.  10 - Installation according to claim 9, characterized in that the flexible gas supply pipe is formed by the sheath of the drive cable.  11 - Installation according to claim 9 or 10, characterized in that the carriage (28) is made in the form of a devil.  12 - Installation according to one of claims 8 to 11, characterized in that it comprises:  - a rotor (2) according to claim 6 or 7,  - Means for supplying flux in powder form.  13 - Installation according to claim 12 and one of claims 9 to 12, characterized:  - in that it comprises a rotor (2) according to claim 7,  - and in that the flow supply means include a source  flow fitting on the carriage (28) and connected to the pipeline  input (50) of the rotor (2) by a flexible pipe.