DE1446181B1 - Process for coating ceramic or metal particles with a metal and reaction vessel to carry out the process - Google Patents

Description

ί 446 181

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The invention relates to a method for over- The object of the present invention is

attract ceramic or metal particles with one therefore in avoiding these disadvantages and a Metal by passing through Metallcarbonyldämpf en process and a system for carrying out this by creating a bed kept moving from the part process, with which to create large particles at a temperature high enough to mix with the metal of the metal carbonyl over the To decompose metal carbonyl, as well as to be able to pull a reactor, an effective decomposition of to carry out the decomposition of Metallcarbo-Metallcarbonylen with large throughputs and nyl steaming and for coating particles according to at higher mean temperatures than it is with the previous one Procedure. is the case, can be achieved

There is already a cata- io manufacturing method.

Lytically effective metal coatings on finely divided This is achieved according to the invention in that

Carriers, the carrier particles in a the particles in the form of a slowly moving bed vertical reaction tube being held freely falling from the plating reactor in a rotary reactor, the gas that is sufficiently high on its decomposition temperature movement to create an agglomeration is heated, known. The carrier particles 15 to prevent tion of the particles, but low enough are suspended by the plating gas flow to a significant mechanical kept so as to avoid the plating reaction in an abrasion and the metal carbonyl vapors Fluidized bed takes place. Such a process has to be initiated below the surface of the bed, the disadvantage that especially when using high This has the advantage that metal carbonyls with very

Carbonyl concentrations result in complete high-speed, high-transmittance decomposition the carbonyls do not take place. Furthermore, in a very high concentration in a plant with the fluidized bed, where the particles carried by the gas can be decomposed in a relatively small volume, be, the gas flow is not constant. Furthermore, carbonyl materials can with very can be changed, whereby the risk of agglomeration high metal carbonyl content are used. the consists of particles. 25 moderate movement of the bed of the preheated metal

In another known method, ele particles, in which the carbonyl vapor is decomposed, prevent the material from sticking together, even the deposition of the elemental metal from a metal containing a high concentration of metal carbonyl in the same Heat decomposable, when the material to be fed to the bed is present, the treatment temperature is vaporous or gaseous. In addition, a practically complete binding is applied to the surface of the support, which is heated to the decomposition temperature of this decomposition of the carbonyl in a very short time. The slow rolling motion of the reaction wearer. The surface of the bed to be treated leads to the fact that between the particles, the substrate is continuously heated under vacuum and the heat naturally causes a relative movement that prevents the particles from sticking, decomposable at the treatment temperature, while at the same time or Gaseous compounds in contact with this form a bed of particles which are brought into permanent, alternating surface. This process has the disadvantage that there is physical contact on the side, which is obtained when metal carbonyls are used. Countless, continuous decomposition does not take place, so that the exhaust gas still contains carbonyl which changes all around the way through which it is carried out. Such a complete 40 of the carbonyl vapors through the particle bed, and the decomposition is also not possible because a residence time of the carbonyl vapors in the bed means movement of the particles takes place through which the optimal. Complete decomposition of the metal carbonyl gas stream passes through it. In order to vaporize the residual vapors through the depth of the continuously, a condensation chamber must therefore be set up for this running particle bed,
necessary. Another disadvantage arises from the fact that it is particularly expedient if the particles have to be drawn through the process mainly under vacuum from the decomposition zone and carried out for delivery Apparatus expense and increased production and metal carbonyls required heat leads to operating costs. Preheater are passed. Advantage-

Devices have also been used in which the metal carbonyl is liable to be in the form of a Pellets move down a shaft and vapor with a concentration of more than 50% supplied by upwardly moving carbonyl in countercurrent. It has a beneficial effect Nickel carbonyl are flowed around, which decomposes, the inventive method when the too whereby nickel is deposited on the pellets. coating particles to a temperature above Due to the indirect heat exchange and the difficult heat distribution of the decomposition temperature of the metal to be decomposed, these vertical carbonyls have, however, at a temperature below the Decomposition plants only have limited capacities. A temperature at which a significant large-scale production of coal therefore only takes place with the formation of a substance can be heated. It is there too A large number of such systems are possible. It is also possible that more than one metal carbonyl is on top of one another the throughput rate of the carbonyl consequently into the decomposition zone for decomposition and delimits that an adhesion of the pellets and one therefrom to the formation of different metal layers resulting blockage of the shaft avoids the introduction of the particles.

which would occur if the person responsible for carrying out the decomposition of metal

Carbonyl content in the supplied gas a certain carbonyl vapors and for coating particles Concentration exceeds. The nickel content must be 65 used according to the method of the invention these plants generally below 15% of the reactor consists of a rotatable jacket with theoretical maximum are kept, creating a gas-tight solids supply line and Entdie Production capacity is further limited. receiving openings at the opposite ends

His drive device for rotating the jacket Fig. 8 shows a further in a longitudinal section

on a central longitudinal axis and leak-tight gas inlet form of the rotating reactor:
drain lines and outlet lines. This reactor F i g. 9 schematically shows a longitudinal section

is characterized in that the inlet lines in the embodiment in which the particle preheater is assembled essentially at equal intervals around the rotating carbonyl reactor.
len jacket are attached and gas flow control organs, as particles to be coated can be, for example

iie at any one time only one gas inlet in the lower wise pellets, meal, grains, or agglomerates Part of the rotating jacket allow you to attach to each powder from your metal of carbonyl, a different one ler said gas inlet pipes leading pipe metal, non-metallic! Material, "ceramic, fire-rated are. solid or glass-like materials can be used. the

The reactor is expediently sized to a size of these seed particles slight inclination from the horizontal, - the speed and volume of the influx and to facilitate the flow of particles. discharged gases determined, i.e. there can be none

Advantageously, seed particles are used at the solids removal which essentially diffuse an Aüstragsvorrichtung attached and with 15 borrowed be blown out of the reaction vessel » A solids transport system including a The particles produced in the reaction vessel itself / heater to the solids charging opening have a size range between powder grains. size and balls 2.54 cm in diameter.

The feeder expediently consists of the particle size is essentially of the Carinem rotary vessel, which is attached to the reactor ao bonyl concentration, the temperature of the solids and rotates with this around a common axis; and the residence time in the reactor.
ir is also with a solids outlet port * which The seed or core particles A become in one

u the solids feed port on the reactor is preheated to the particle preheater B and then fed to the flow reactor C via a gas inlet line. In the somewhat inclined, expensive elements to enable the gas flow to be found only in slowly rotating reactor C with the lower part of the rotary vessel to be covered, the particle feed, which resides in it as a moving bed, differs. The solids circulation system is continuously mixed by falling on top of each other, using a discharge device which becomes the outlet of the metal carbonyl vapors are passed through the 'replacement zone and the inlet of the preheating particles and decomposed, with the one combining. 30 particles of metal are deposited. The coated particles D

It is particularly favorable if the gas inlet lines are brought out of the reactor C and sorted according to size in one operation in the inner curved surface of the jacket, whereby they are inserted and protrude beyond the same. The desired product portion F and a portion G with 'let control members in each of the gas inlet lines at the undersize is obtained, which can then be fed to the reactor C again for preheating and) rowing of the jacket to enable a gas flow. They are actuated when the gas inlet lines H from the reactor C consist mainly of carbon monoxide in the lower part of the rotation and can be used in the operation / control elements in each gas inlet line for the production of metal carbonyl vapors. be turned *

The reactor shown in Fig. 2 consists of a 3-rail _s which are operated in the lower part of the passageway, rotatable, cylindrical casing 11 made of mild steel, the casing appearing. A special lining does not have to be provided) The actuating levers open the flow control organs, since the decomposition of the carbonyl vapors is practically complete as they slide along the guide rails and the particle charge. After the end of the sliding along the reactor, the jhließen stands on guide rings 13 on rollers 12 from en guide rails. one or more of which are driven by a

With the help of such a built reactor it is direction 14 can be driven so that lögliehi a uniform heat and steam or, the reactor rotates. The gas-tight solid loading glass distribution to achieve and a metal carbonyl opening 15 for vorfaitzte particles, wi & nickel pellets, to generate practically free gas. 5 ° in the reactor is held by a stationary housing 16

With the aid of the drawings, for example, the wear-resistant seals 17 The embodiments of the present invention are in sliding contact with the reactor, nschaulichti The inner surfaces of the seal 17 is at the local

Fi gi 1 shows in a flow diagram the stages of the fixed housing 16 by means of a flange l £ and the method according to the invention; 55 Outer surface of the seal 18 on the drive

Fig. 2, a longitudinal section through an inventive device 14 is attached so that it rotates therewith. For the 3-size, rotating decomposition plant; Pressing the seals 17 and 18 against each other can-

Fig. 3 is a cross-sectional view of the decomposition plant a suitable tensioning device can be provided dt introduced and distributed in the company; The particles coated in the reactor will

F i g. 4 shows a cross section through the 60 through the removal opening 29 attached to the reactor Yawing reactor removes the movement of particles caused by a stationary etiiahm of operation; container 21 is sealed gas-tight. At the removal

Fig. Figure 5 is a partial view taken along line 5-5 of container 21 and inner seal 22 is on

ig. 2; Removal opening20 an outer seal. 23 loading

Figure 6 shows a partial section of a control valve 65 that rotates with the reactor. The wear the; Carbonyl vapor inlet; fixed seals 22 and 23 are in a sliding

Fig. 7 shows a further embodiment for the contact and are made by suitable Spannvorrichufführung of metal carbonyl vapors; pressed against each other. The outlet port 24

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of the withdrawal container 21 is also gas-tight - they are thrown on top of each other at the same time, flow

guided. As the particles gradually move over the edge of the

Through leak-tight gas inlet lines 23, which are taken with opening 20.

to the. Jacket 11 of the reactor connected and drum- In Fig. 4 the movement of the feed 60 is at are distributed around, the metal carbonyl 5 of the rotation of the reactor are indicated by arrows 62, in the present case nickel carbonyl vapor, draws, with each particle being circular introduced. The supply and distribution is tracked via route within the feed and then an annular pipe 26 "which is connected to the reactor along the surface of the feed in the turbu- and into which lines 27 open, which reach the inlet lente transition zone 62a. Renewed as a result lines or inlet openings 25 lead, in the i ° the surface of the charge continuously. Lines 27 are steam flow control elements 28 in FIG. 3 with 58 a and in F i g. 4 anticipated with 61. The particle bed depth drawn from the annular tube 26, the lines, is, as mentioned, so fixed with controls 28 and the inlet line 25 attaches that virtually all metal carbonyl vapors that formed distribution unit rotates with the reac- be passed through the bed, are offset before they gate. The inlet lines 25 extend into the free space in the reactor. the Inside the reactor, what is determined by the projections 29 particle bed depth is thus dependent on the temperature and the is indicated. Concentration of the supplied carbonyl vapors and avoided that carbonyl vapors with the jacket 11 dependent in their flow rate. The Rota touch come. The steam flow controlor- tion of the reactor requires a uniform and congane 28 are only open when the partial 20 continuous rotation of the particles and a conical feed is above the inlet line 25, so continuous relative movement of the parts to one another, that the carbonyl vapors up through the load flow in the reactor. The actuation of the moderate metal deposit by the decomposition of the Steam flow controllers, d. H. their opening and vapors, so that excessive growth of the part-closing, takes place via a stationary curved 25 surfaces and an adhesion of individual particles to a guide rail 30, which is avoided via operating lever 31 other. Due to the constantly changing and valve rods 32 the respective steam flow - the contact points of the particles due to the Control members 28 controls accordingly. The mixed effect of the bed is obtained in numerous ways The supply of nickel carbonyl vapors to the ring - constantly forming new passage channels for the Carrohr26 takes place via a stationary steam supply pipe 51 30 bonyldampf, whereby an effective and complete and the connecting line 52. The connecting line decomposition of the steam is achieved tion 52, which opens into the annular tube 26, rotates with In F i g. 6 is an example of a steam flow rate Reactor. The connection with the stationary control element 28, which is referred to below as a valve Steam supply pipe 51 takes place via sealing rings 53 and 54. Should be shown. The carbinyl vapors flow That from the feed in the reactor 35 through the inlet channel 33 of the leakproof valve 28 Exiting gas is via an exhaust gas outlet line 55, from the annular tube 26 into the chamber 34 and, if which branches off from the solids feed opening 15, the valve is open, into the space 35 and through the discharged. Outlet channel 36 into line 27. The closing of the inlet lines 25 and in particular their valve 28 is effected by a compression spring 37, which is at 38 Projections 29 in close contact with the particles in 40 the upper part of the nut 39, which is connected to the valve dem Come reactor, it must be avoided that rod 32 is connected, pushes down, so that the they get too hot so that a decomposition of the car seal 40 lies against the shoulder 41 in a sealing manner, bonyl fumes on it and thus a plating of the If the operating lever 31 is on the point of Metal does not occur. In order to achieve this, one cools the curved guide rail 33 moved by the expediently the inlet lines 25, in that the valve is opened 45, the valve rod 32 water is supplied via spray bracket 56, which moves together with the nut attached to it, along the perimeter of the reactor where inlet lines 25 allow the carbonyl vapors from chamber 34 to enter the are attached, flows. It is also useful to space 35 and through the outlet channel 36 into the Leidie Connection line 52, which can flow with the heated from tion 27 to the reactor. A cylinder Reactor discharged during removal 50 drical guide part 42 that is charged to the nut 39 can come into contact by one as is fixed, ensures the correct seating of the seal 40 To cool pipe 57 formed cooling water jacket. at the shoulder 41. A lick between the valve-Das Tube 57 ends in a scoop 58, which is attached to each head 43 and the valve rod 32 through a Rotation of the reactor in a cooling water bellows 44 prevented, which is attached to the nut 39 at 45 and immersed in the container and absorbs cooling water. While 55 at its upper end on the valve head 43 over the the rotation of the reactor runs the heated seal 46 is attached leak-tight. Water from the open end of the pipe 57 again Instead of the valve 28, however, any before it reunites another suitable steam flow control element in the cooling water tank. However, the cooling devices can also be turned, such as with a piston be omitted if the feeder has 60 cam operated valves or solenoid valves, is dimensioned in such a way that the carbonyl vapors in It can, however, also be a sliding or sliding spring Completely decompose the feed. valve can be used as shown in FIG. 7 is shown. From the in F i g. 3 shown cross section of the Re- The metal carbonyl vapors to the plate actuator can be seen that the height of the particle 47 with a curved slot provided therein Dispatch 59 passed through the size of the removal opening 20 65 48. The plate 47 is gas-tight on a plate 49 is determined. During the rotation of the reactor, with holes 50 made, each with a mouth in which the contained therein, a line 27 to be coated form. This rotates the Particles flow from inlet to outlet end and plate 49 with lines 27 and the reactor,

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while the plate 48 is stationary and connected to the steam feed outlet opening 66 with a reactor 65, guide tube 51 is connected. If the two containers are suitably arranged, the slot 48 is arranged by means of races 68 on rollers 67, the metal carbonyl runs. The device is guided via a drive vapor only through the steam inlet lines 25 in the direction 69 through a reactor attached to the reactor 56, which then drives the steam through the 5 ring ring. Continue the particulate loading charge. Like nickel pellets and seed material for nickel pellets The depth of the particle bed in the reactor can, as mentioned like nickel grist, nickel powder or nickel powder, through the size of the reactor discharge agglomerates is introduced into the rotary vessel 64 through the opening 20 and / or through the inclination of the reactor feed inlet 71 . The particle opening can be varied by the long rotation of the rotary vessel 64 from the solids feed opening to the removal. The deeper the particle bed is, slowly one above the other and are mixed, the more inlet openings 25 for metal carbonyl while vapors through gas inlets 72 via the feed line 73 can be provided. The capacity of the hot coal reactor fed to and the feed line 74 increases approximately with the square of the monoxide gas fed into the rotary boiler. The diameter and through the use of several controls, as shown in FIGS. 2 and 5 above rows of inlet conduits 25, which are written on the jacket 11, supplied gas flows upward through are mounted opening around into the reactor. A übereinanderf allenden the particles heated, these and such a reactor is shown in F i g, 8, wherein the is discharged through the gas outlet 75 miles. Length of the reactor compared to that of FIG. 1 The preheated particles arrive using the

is double and several rows of inlet openings 20 scooping device 76 from the rotary boiler 74 for the 63 are provided. As a result, capacity preheating through the solids outlet opening 66 is doubled achieved. If one inclines, as previously noted, into the reactor 65, where they turn, because the rotation thinks that the longitudinal axis of the reactor in a small one of the reactor and the rotating vessel are the same, slowly Angle to the horizontal, so that the dispensing openings fall on top of each other and are mixed. About the 20 is lower than the solids feed opening 25 feed line 77, the feed lines 78 and the 15, the passage of the particles through the steam inlets 79 will be nickel carbonyl vapor over Reactor and the particle removal facilitated and corresponding controls in the reactor 65 so one lower reactor speeds possible. That led to the .Carbonyl vapors always up Particle passage is faster and the dwell is passed through the particle feed. the the time between the heating stages becomes shorter. 30 resulting from the decomposition of the carbonyl vapors

With a 0.9 m long reactor, the gases are removed from the reactor 65 through the exhaust gas meter of 1.2 m and with a partial bed depth 80 line. The common axis of Revon Works 0.51m at the carbonyl steam inlet, the actuator and rotary boiler are preferably slightly inclined, along a row on the circumference of the jacket 11, the reactor 65 being lower. This will 1360 kg of nickel per day can be generated by the flow of particles through the two containers with the vapors at the inlet lightened by over 50%. From the reactor 65 the particles pass Contain nickel carbonyl. The limit for the conduits outlet 81 and fall on the screw conveyor 82, centering is only due to the formation of liquid which it conveys to the feed hopper 83. That Carbonyl limited in the supplied steam. The outlet end of the screw 82 is provided with a sluice 84

In a 6.1 m long reactor with a through-40 which only opens when the outlet is above the knife of 4.8 m and with a partial bed depth of Beschioküngfunnel 83 stands. Appropriately 2.1m can be the seed particles through the at this point with a similar carbonyl vapor Concentration of over 136,000 kg of nickel generated per day provided feed opening 85 was added. the will. from the lock 84 coming particles are over

The pellets or particles should, when nickel car- 45 passed the sieve 86, the finished coated Bonyldampf is used, to 177 to 288 ° C pre-particles discharged through the outlet channel 87 and the are heated, with a temperature of 204 ° C falling into a funnel 88 particles that are still too small is preferred. One tries to leave the loading as it is. These particles become new along with the as high as possible, the limit being fed back into the rotary kettle 64 the formation of carbon is given. This limit 5 ° introduced via the lock 89 and the line 90 can be heated up and preheated again by additives such as ammonia. For a leak-proof gas flow be pushed. The withdrawal temperature of the excess are in the supply line 74 for the carbon monoxide withdrawn Particles from the reactor should be at 149 ° C gas and the feed line 77 for the nickel carbonyl and lie above. Preheating can be provided by steam seals 91 or 92. Equal radiation, electrically, through indirect heat passes, are at the inlet end of the rotary vessel 64 and at the exchange or by direct heat exchange with the outlet end of the reactor 65 seals 93 and 94 a gas like carbon monoxide that is installed in the system.

Cycle is carried out. Preheating The table below shows the results

can be carried out in an extra zone, for example by one of six experiments that are carried out with a re-fluidized bed with carbon monoxide with carrier gas or an actuator with an internal diameter of 1.2 m and a length in the reactor, with hot of 0.9 m being carried out . As a seed material, gas is blown into the particles at locations that; fine nickel grist added, located away from the reactor from the metal carbonyl inlet points. are dense, uniformly sized pellets of 1.27 cm to be expedient design challenges a diameter and a relatively smooth surface has entnomgestellt, wherein the Vorerbitzungsanlage and the Re- 65 men. Such pellets are especially assembled for the Heraktor and rotate around a common position of special steels, high temperature alloy axis, as shown in FIG. A gene or can be used for purposes where very pure rotary kettle 64 is required for preheating via a solid metal, in the present case nickel.

009529/186

9 Added Ni, kg / h. ^A. B. 10 attempt C. ^{D. E.} F. Supplied steam, m ³ / min 21.8 23.1 18.1 37.6 46.5 57.1 Added Ni / steam, g / m ³ 0.60 0.65 0.75 0.765 0.793 0.821 Exhaust gas, m ³ / min 600 580 400 820 975 1160 Discharged Ni / waste gas, g / m ³ 1.09 1.11 1.28 1.67 1.84 2.10 Degree of decomposition,% 0.47 0.38 0.11 0.44 0.44 0.16 Particle ^addition temperature, 0 C 99.87 99.89 99.96 99.90 99.91 99.97 Pellet removal temperature, ⁰ C 232 to 249 188 to 213 213 to 240 241 to 243 236 to 239 233 196 to 213 177 to 196 191 to 216 201 to 204 193 to 199 188

The inventive method, it is not only possible to metal particles with the same or to coat another metal, but metal alloys can also be made by using the individual metal carbonyls are mixed accordingly. Such alloy particles can are then subjected to appropriate post-treatment. Furthermore, it is not necessary to be single Metal carbonyl vapors are supplied. Instead, other suitable metal compound vapors, which decompose in the reactor according to the invention and deposit metal, can be used. Such compounds are, for example, cobalt nitrosyl carbonyl, tin hydride, antimony hydride, beryllium iodide and nickel iodide.

Claims (14)

Patent claims: 1. Process for coating ceramic or metal particles with a metal by means of Passing metal carbonyl vapors through a bed of particles kept in motion at a temperature high enough to decompose the metal carbonyl thereby characterized in that the particles are in the form of a slowly moving bed in a rotary reaction vessel The agitation is sufficiently high to prevent agglomeration of the particles, but low is enough to avoid significant mechanical abrasion, and the Metal carbonyl vapors are introduced below the surface of the bed. 2. The method according to claim. 1, characterized in that that the particles are withdrawn from the decomposition zone and used to deliver at least a part of the heat required for the decomposition of the metal carbonyl through a preheating device be directed. 3. The method according to any one of claims 1 or 2, characterized in that the metal carbonyl is supplied in the form of a vapor with a concentration of more than 50% carbonyl. 4. The method according to any one of the preceding claims, characterized in that the to coating particles to a temperature above the decomposition temperature of the one to be decomposed Metal carbonyls, but at a temperature below the temperature at which a significant Carbon formation occurs when heated. 5. The method according to any one of claims 1 to 4, characterized in that more than one metal carbonyl successively into the decomposition zone for decomposition and the formation of different Metal layers are introduced onto the particles. 6. Reaction flow for carrying out the decomposition of metal carbonyl vapors and for Coating particles according to the method of claim 1 consisting of a rotatable jacket with a gas-tight solids supply line and extraction openings on the opposite side Ends, drive means for rotating the jacket about a central longitudinal axis and leak-tight gas inlet and outlet lines consists, characterized in that the inlet line (25) is substantially equidistant mounted around the rotating jacket and gas flow controls (28) which only one at a time Allow gas inlet into the lower part of the rotatable jacket at the gas inlet ducts to each of said gas inlet ducts leading lines are provided. 7. Reaction vessel according to claim 6, characterized in that the reactor (C) at a slight inclination from the horizontal for relief of the particle flow is maintained. 8. Reaction vessel according to one of claims 6 or 7, characterized in that a discharge device (82) attached to the solids removal opening and with a solids transport system (82, 84) including a preheater (64) connected to the solids feed opening (15) is. 9. Reaction vessel according to claim 8, characterized in that the preheater consists of a Rotary boiler (64), which is attached to the reactor and with this around a common Axis rotates, and also with a solids outlet opening (66), which leads to the solids feed opening (15) leads to the reactor, and furthermore with a gas inlet line (72) the flow control elements (28) to enable the gas flow only in the lower part of the rotary boiler. 10. Reaction vessel according to claim 9, characterized in that the solids circulation system consists of a discharge device (82), the outlet (81) of the decomposition zone and the inlet (84) connects the preheating zone. 11. Reaction vessel according to one of claims 6 to 10, characterized in that the gas inlet lines are inserted into and over the inner curved surface of the shell stand out. 12. Reaction vessel according to one of claims 6 to 11, characterized in that the flow control members (28) are set up so that they are in each of the gas inlet conduits then rotating the jacket to allow gas flow operated when the gas inlet lines are in the lower part of the rotation. 13. Reaction vessel according to claim 12, characterized characterized in that the flow control elements in each of the gas inlet lines (27) actuate levers (31) have, which correspond to, attached stationary curved guide rails (30), the appearing at the lower part of the passage of the jacket. 14. Reaktiönsgefäß according to claim 13, characterized characterized in that the operating lever (31) the flow control members (28) when sliding along the Open the guide rails (30) and the flow control members after the end of sliding along close the guide rails. For this purpose 2 sheets of drawings