APPARATUS TO INTRODUCE A FLUID IN A CONTAINER An apparatus is used to introduce a fluid into a container, particularly for the subsequent stabilization of substances that are usually stored in containers or storage tanks and that are distinguished by a strong tendency towards chemical reactions undesirable such as, for example, premature polymerization, or other physical reactions, for example crystallization. It is known that certain substances or combinations of substances in solid or dissolved form are suitable for re-stabilizing polymerizable substances that react at an undesirable moment. These substances can be introduced into the material stored in a conventional manner and then mixed with the contents of the tank through the pump that is commonly used for tank installations and that are provided for the purpose of filling and emptying tanks. The disadvantage here is that the pumps themselves may be the starting point of a premature polymerization that causes the blockage of the pump. Therefore, the mixing function can no longer be carried out when required. A further disadvantage is the dependence of an external energy source to drive the pump which, as a result of an emergency or chance, may not be available so that a stabilizing liquid can not be introduced. In order to be independent of external sources of energy, a mixing process that includes blowing gases is also used. A disadvantage is that additional deflectors must be supplied for this purpose inside the tank itself or on the tank. In general, such baffles should be firmly anchored in the tank to prevent them from being damaged or broken up during normal operation. In order to be effective, that is, to achieve good mixing, the baffles to force the gases inward are usually placed near the bottom of the tank. When these baffles are not in use, the reactive substance can penetrate the deflectors and gradually polymerize there due to the slight exchange of material in such a way that, when required, the gas supply will be useless. Therefore, a small air stream is often passed through these lines in order to keep these lines free. However, said air current also needs to be monitored through devices to prevent the liquid stored in the tank from rising and to keep the line open. The realization of such designs to perform reliably the expected function represents a significant economic cost. EP-B 0 064 628 discloses an apparatus for emergency stopping the polymerization reactions in a closed reaction vessel by the addition of a solution of inhibitors. The addition is made in the lower region of the container through a closed connection flange with a bursting disc. Mounted on this connection flange is a line of ascending ducts with an angle to an upper flange to which a gas line under pressure is connected. The rising line is filled with an inhibitor solution which, when required, is forced into the vessel by the gas under pressure. Even when the operating capacity of the apparatus must be independent of polymers formed into cakes and power supply failure, the regular monitoring usually required for safety devices is more difficult in the case of these immersed baffles, and the bursting disc may be checked only when the container is in an empty state. However, this means that the tank can not be used during the cleaning and inspection process. According to the invention, the delivery device is in the form of a telescopic tube which can be extended by the fluid pressure in the internal part of the container and is mounted on the highest level in the container. In the novel deviceWhen necessary, the activated telescopic tube is automatically immersed in the material present in the container and carries liquid or gaseous substances in the material and simultaneously mixes the substances with the material. The fluid under pressure can be introduced into the container to stabilize the substances present in the container and can be a mixture of a gas and a liquid. Since the apparatus is installed above the highest allowable level in the container, it comes in contact with the material present in the container only when required, so that the operating capacity is not affected by the material present in the container. In addition, the apparatus can be mounted in the container or removed at any given time, regardless of whether the container is in operation or not. This makes it possible to carry out a regular operation test in a simple manner. Due to the design of the appliance it can be installed without changing dimensions, in containers with very different contents without influencing efficiency or operating capacity. Next, preferred embodiments will be described. In the drawing, a novel apparatus is shown. Figure 1 shows a schematic cross section through an apparatus installed in a container wall and having a telescopic tube in retracted position, Figure 2 shows the telescopically extended tube, Figure 3 shows a detail of an apparatus of lock for the telescopic tube and Figure 4 shows in apparatus with the first inner tube of the telescopic tube fully extended from the frame tube. Figure 1 is a schematic cross section through a novel device installed in the container wall 1. The container wall 1 has a hole 2 with a vertical connection flange 3. A telescopic tube 4 of the apparatus for introducing fluid into the Internal part 5 of the container blocked by the container wall 1 projects through the hole 2. The telescopic tube 4 consists of an external frame tube 10 and three internal tubes-13, sealed between them through seal means 14 The internal tubes 11-13 have, at their ends, retaining rings 15, 16 which limit the axial movement of the internal tubes 11-13 when they are removed. The central inner tube 13 is equipped at its end 13.1 located on the inner part 5, with a fastener 17 for a burst disk 18. Furthermore, the fastener 17 extends outwardly in such a manner that the other inner tubes 11, 12 can lean on it. At the other end 13.2, the inner tube 13 has an internal collar 19 and an extension 20 that extends above the retaining ring 16 and whose function will be explained later. The frame tube 10 has a support flange 21 for fastening on the flange 3 of the container wall 1, it being possible to hold it directly or with the use of an intermediate flange 22. In addition, the frame tube 10 has a second flange 23 for securing a blocking device 24. A supply line (not shown) for the fluid to be introduced in the inner part 5 is connected to this blocking apparatus via a pipeline flange 25. The blocking apparatus 24 comprises a frame 26 enclosing a piston chamber 27 connected directly to the duct flange 25 in terms of flow, with formation of an internal part 28. In the piston chamber 27 there is a piston 29 which, in the initial state, is present. inside the piston chamber 27 in the position facing the pipeline flange 25. In the region not covered by the piston 29, the piston chamber 27 has a hole 31 which provides the connection, allowing the flow with the piston chamber 27. to inner part 28. This hole 31, which may have the shape of a slit, does not open until the piston 29 reaches a lower position. The inner part 28 is connected through an additional hole 22 to a pressure chamber 33_ blocked by the blocking apparatus 24 and the inner tubes 11-13 located within the frame tube 10 and from which the movement of inner tubes 11-13 begins when a fluid is applied under pressure. The flow that allows the connection is indicated by the arrows. In addition, means are provided for locking and releasing the inner tubes 11-13 in the pressure chamber 33, said means are described in greater detail with respect to Figure 2. In Figure 2, the telescopic tube 4 is shown extended from a distance. For this purpose, the locking apparatus was operated in such a manner that the piston 29 is in a lower position within the piston chamber 27. As a result of the axial displacement of the piston 29, detents 34 present in the pressure chamber 33. they are released from the locking openings 35 in the upper end 13.2 of the central inner tube 13. This release movement is indicated by the arrows 36. Moreover, during its axial displacement, the piston 29 comes to rest against the inner collar 19 already helped the extension movement of the internal tubes 11-13. To allow this release, the detents 34 are mounted on spring tongues 37 and have a surface 38 facing the piston 29, is beveled in the direction of movement and is illustrated on a larger scale in Figure 3. In the locked position, the detents 34 extend through the blocking openings 35 of the upper end 13.2 of the inner tube 13 and penetrate a certain distance in a recess 39 in the piston 29. The recess 39 has a shape corresponding to the seals, such so that the retainer slides on its bevelled surface 38 out of recess 39 during axial displacement of the piston. To reduce friction, the retainer 34 may consist of PTFE (polytetrafluoroethylene). In the embodiment, the locking openings 35 are apertures in the form of slits cut in the upper section of the central inner tube 13. To prevent the detents 34 from sliding out unintentionally under the effect of the gravity of the piston 29, the r_etén it can be arranged in an appropriately rigid spring tongue 37 or a lever with spring loading. The initial tension of the spring tongue 27 is chosen in such a way that the force due to the weight of the piston 29 and acting on the bevelled surface 38 is at least compensated. Since the retainer must also carry the total weight of the inner tubes 11-13, it has in addition to the sliding region formed by the beveled surface 38, a retaining region having a straight surface 40 that interacts with a corresponding surface of the locking openings 35. As a result of the sliding of the retainer 34 out of the recess 39 in the piston 29, the straight surface 40 is disengaged and the inner tube 13 can also slide under the retainer 34, along the beveled surface 38. movement of the inner tubes 11-13 is initially supported by the piston 29 during its axial displacement, resting against the collar 19, and the extension movement is initiated. Figure 4 shows the apparatus with the outermost inner tube 11 fully extended from the frame tube 10. The volume of the pressure chamber 33 has continuously increased as a result of being subjected to fluid under high pressure. The locking mechanism in figure 4 has completely released the central inner tube 13, whose end 13.2 with the opening 35 is now at the lower end of the frame tube 10. It is clearly evident that, as a result of the displacement of the piston 29 within from the piston chamber 27 to a lower position, the detents 34 have come out of the recess 39 in the piston 29. The bevelled surface 38 of the retainer 34 and the corresponding surface of the recess 39 facilitate this sliding against the spring force of the piston. spring tongue 37. The novel apparatus is fed with the fluid to be introduced through a supply line connected to the pipe flange 25 and is not illustrated. A certain amount of this fluid is available under a certain pressure in a storage container and is not connected to the supply line until a hazard arises. In general, the fluid to be introduced is a liquid that is present in a pressure resistant container. This pressure resistant container can be a conventional extinguisher type container having a bottle of impeller firmly connected. By: 1st opening of the bottle containing the driving agent, the liquid is first expelled from the pressure-resistant container and introduced into the contents of the tank through the telescopic tube 4. The excess gas that flows subsequently produces a complete mixing of the tank liquid with the injected fluid as a result of the flows verticals generated by rising gas bubbles. Accordingly, it suffices that the pressure-resistant container is connected to the supply tube through a quick-acting connection immediately before the opening of the gas bottle. If the storage container is actuated, the pressure prevailing in the storage container is transmitted to the piston 29 in the piston chamber 27. As a result of the force acting on the piston 29, the piston 29 moves in the chamber of the piston 29. piston 27, possibly against the spring force of a pressure spring 30. First, the retainer 34 is released from the recess 29 and consequently the blocking is released; on the other hand, the piston 29 rests on the retaining ring 19 and pushes the central inner tube 13 below the retainers 34 that exit from the locking openings 35. As soon as the piston 29 has reached the lowest retention point in the piston chamber 27, a gas and / or liquid flows through the horizontal holes 31 in the side internal part 28 and through additional holes 32 in a depression chamber 33 above the movable inner tubes 11-13. The force of the applied pressure is now transmitted to the upper end surface of the inner tubes 11-13, the seals 14 between the inner tubes 11-13 and the frame tube 10 and the burst disc 18 adjusted to a certain pressure of gas and placed in the lower end 13.1 of the central inner tube 13 preventing a leakage of pressure in the container. The attempt by the fluid under pressure present in the pressure chamber 13 to expand gradually displaces the inner tubes 11-13 downwards. Due to the larger circumference and therefore the larger contact surface of all the internal internal tubes 11, 12, they initially move downwards. Since the internal inner tubes 11, 12 rest on the holder 17, the central inner tube 13 is also displaced downwards along with these. If the outermost inner tube 11 with its retaining ring 16 bears against the retaining ring 15 of the frame tube 10 the volume of the pressure chamber 33 rises as a result of the downward movement of the next inner tube 12, 13 and the push down. The increase in volume of the pressure chamber 33 is suspended when all the inner tubes 11-13 have reached the lowest retention point or the central inner tube 13 bears against the bottom of the container. If necessary, it is possible to provide a spacer that prevents coverage of the lower end by the bottom of the container and is not illustrated. Since a further expansion of the pressure chamber 33 filled with fluid can no longer occur, a pressure builds up gradually. When the maximum pressure required to destroy the bursting disc 18 has been reached, the fluid present in the pressure chamber 33 expands through the telescopic tubes 4 in the inner part of the container 5. If the fluid that continues to flow is a mixture of liquid and gas, the gas that continues to flow ensures that the forced liquid is mixed with the contents of the container. The apparatus is fastened on the flange of the tank 3 through the support flange 21. For assembly at the desired distance above the maximum level of liquid inside the container, intermediate flanges 22 of different heights can be used. Since the design having a square cross section is preferred for large containers of increasing volumes, the preferred range of use of the invention relates to containers having a volume of 20 to 10Q0 m.3, corresponding to a telescopic extension of 3 to 11 meters. In combination with suitable containers for receiving stabilizing liquid and suitable quick-acting couplings, the apparatus allows economical, reliable and low-maintenance maintenance means, particularly for the storage of reactive substances. The apparatus is especially suitable for carrying out a process for immediately terminating free radical polymerizations by the addition of an inhibitor solution containing phenothiazine to the system which is subjected to free radical polymerization, the solvent of the inhibitor solution comprising minus 50%, based on the weight of said solvent, of an N-alkylpyrrolidone. The N-alkylpyrrolidone may be N-methylpyrrolidone and / or N-ethylpyrrolidone. Furthermore, it is advantageous if the phenothiazine content of the inhibitor solution is at least 10%, preferably about 35-35% by weight based on the weight of the inhibitor solution. The apparatus can be used with advantage particularly when the system subjected to free radical polymerization comprises (meth) acrylic monomers subjected to mass polymerization of free radicals, it being possible that the monomer
(meth) acrylic is a (meth) acrylic acid and particularly a
(met) acrylate. The apparatus is especially suitable for immediately terminating free radical polymerizations, containing an inhibitor solution containing phenothiazine, when the solvent of the inhibitor solution comprises at least 50%, based on the weight of said solvent, of an N- alkylpyrrolidone. In addition, the apparatus is suitable for an inhibitor solution containing phenothiazine and an N-alkylpyrrolidone, particularly N-methylpyrrolidone.