Device and method for cooling a fluid

Abstract

Device for cooling a fluid that solidifies in a predefined temperature range, comprising a cooling chamber (12) for receiving or passing through a cooling medium, at least one pipeline (20) for the fluid, which is arranged at least section by section within the cooling chamber (12), wherein the pipeline (20) runs in a meandering shape and has several straight sections (38, 36) that pass through the cooling chamber (12), and wherein at least one heating device is provided within the pipeline (20).

Description

The invention relates to a device for cooling a fluid solidifying in a predefined temperature range, in particular a melt, having a cooling chamber for receiving or passing through a cooling medium and at least one pipe line for the fluid, which pipe line is arranged at least in sections within the cooling chamber. The invention also relates to a method for cooling a fluid solidifying in a predefined temperature range, in particular a melt, comprising the steps of conducting the fluid through at least one pipeline of a cooler, wherein the pipeline is surrounded by a cooling medium, and detecting a temperature of the fluid in the region of the pipeline.From the German Auslegeschrift DE 10 12 426 A a device for temporarily interrupting and restarting the flow of molten substances, in particular polyamides, within a heatable plant is known. The molten polyamide is guided in a pipe surrounded by a heating jacket which is also tubular and through which a heating liquid or a heating gas circulates. At a location where the flow of the polyamide is to be stopped, the piping for the polyamide is surrounded by an annular chamber through which cold air can be blown. In the region of the annular chamber, the polyamide is thereby cooled down and solidifies to form a plug. As a result, the flow of the polyamide is interrupted. In order to reflow the molten polyamide, it is sufficient to interrupt the blowing of cold air to allow the plug to reflow under the action of the heating liquid or gas in the jacket of the pipe. Additional heating means in the form of an electrical resistor may be provided, which are arranged in the region of the annular chamber where the solidified plug forms.International patent publication WO 2012 / 156 472 A1 discloses a pipeline for conveying a molten salt. The pipeline is intended for use in parabolic trough solar power plants, for example. If the solar power plant is not operating, for example at night, the salt melt can solidify. When reflowing occurs, damage may occur in the pipeline. In order to prevent damage, a heating wire is guided inside the pipeline, which does not lie against the inner wall of the pipeline. By means of such a heating conductor, it is possible to melt salt solidified along the heating conductor uniformly within the pipeline. As a result, a channel is formed within the solidified salt, through which channel molten salt can be transported away, so that excessively high pressures are not exerted on the pipeline.German laid-open specification DE 199 41 901 A1 discloses a tubular heater for heating fluids, which serves, for example, in washing machines for heating the wash water or the wash liquor. An electric heating coil is embedded in insulating material and disposed within a tube. This tube then projects into an aperture in the wall of a wash tub of the washing machine.U.S. Pat. No. 1,773,249 A discloses a condenser for a cooling system. The condenser has a meandering pipeline. In the region of the straight sections of the meandering pipelines, these are connected to one another by means of air baffles.U.S. Pat. No. 2,109,926 A discloses an air cooling device which has a pipeline in which the air to be cooled is guided, the pipeline being guided through a container with cooling liquid. Swirl plates are arranged within the pipeline.German patent specification DE 20 35 630 C3 discloses an apparatus for producing gaseous olefins by thermal cleavage of liquid or gaseous hydrocarbons. A set of heating tubes is guided through the process chamber of a reaction tower, wherein the heating tubes pass horizontally through the reaction tower and are arranged one above the other in a plurality of layers. The heating tubes of adjacent layers are arranged offset from one another.An ice machine is known from U.S. Patent Application US 2001 / 0 011 460 A1. The ice machine is used for producing ice cubes. Water is introduced into a mold via an inlet line. The shape and a portion of the feed conduit are located within a freezing chamber. In the opening region of the inlet, a helical heating device and a temperature sensor are provided. If the temperature in the feed falls below a predetermined temperature and there is a risk of the feed being clogged by ice formation, the heating is put into operation.From British Patent Specification GB 1 337 980 A a dryer for sheet materials, for example paper webs, is known. The paper web is passed between a plurality of semi-cylindrical drying sections.U.S. Pat. No. 1,742,391 A discloses an apparatus for solidifying sulfur. The molten sulfur is introduced into a trough at the bottom of which a heating pipe extends. Steam is applied to the heating line to maintain the sulfur within the trough in the molten state. Molten sulfur is then introduced into a ladle located below the trough, in which the sulfur can then solidify.The invention is intended to improve an apparatus and a method for cooling a fluid solidifying in a predefined temperature range.According to the invention, a device having the features of claim 1 or a method having the features of claim 15 is provided for this purpose. Advantageous refinements are specified in the dependent claims.According to the invention, a device for cooling a fluid solidifying in a predefined temperature range, in particular a melt, is thus provided, having a cooling space for receiving or passing through a cooling medium, at least one pipe line for the fluid, which pipe line is arranged at least in sections within the cooling space, in which at least one heating device arranged within the pipe line is provided.When cooling fluids which solidify in a predefined temperature range, care must always be taken that the fluid does not solidify within the cooler itself, but rather is only cooled to such an extent that it still remains flowable. Partial solidification is also critical, since deposits can lead to blockages of the cooler over a long term. Such solidification within the cooler during melting and in particular during cooling of a sulphur melt is particularly critical. For the purpose of granulating sulfur, it is optimal to feed the still liquid sulfur melt to a drop former at a temperature which is only slightly above the solidification temperature of sulfur. This can be problematic, however, if the temperature inside the cooler falls too far, since solidification inside the cooler and thus blockages must then be feared. The invention provides a remedy here by arranging a heating device within the pipeline leading through the cooling space. If the temperature of the fluid, in particular of the sulphur melt, within the pipeline now falls below a predefined temperature value, the heating device is activated. The fluid within the pipeline is thereby heated starting from the heating device and it is not only possible to prevent the fluid in the pipeline from solidifying further, but it can even be achieved that consolidations already formed are liquefied again within the pipeline. Surprisingly, the provision of heating devices is extremely advantageous, in particular when a sulphur melt is to be cooled. This is because, by means of the invention, it is possible for the first time, without having to carry the risk of solidifications within the cooler, to cool down the sulfur to a temperature which is optimum for the pelleting.According to the invention, the pipeline has a plurality of straight sections which are guided through the cooling space.It has proven particularly advantageous to arrange a plurality of rectilinear sections of the pipeline in the cooling space in order to utilize the cooling space as well as possible in this way. Deflections between the individual rectilinear sections, on the other hand, are advantageously arranged outside the cooling space. In this way, the device according to the invention can be easily mounted and the pipelines are accessible, above all, without problems for any maintenance or cleaning.In a further development of the invention, the heating device is designed as a heating line.For example, hot water or steam can be conducted through the heating line in order to thereby heat the fluid within the pipeline very quickly and optionally re-liquify solidifications.In a further development of the invention, the heating line runs in a U-shape and is designed as a heating lance which can be pushed into the pipeline.By providing a U-shaped heating line, the heating medium, for example water or steam, can be conducted in a circuit through the heating lance. By providing a heating lance which can be inserted into the pipeline, the device according to the invention can be produced without problems and, above all, can also be maintained and cleaned.In a further development of the invention, the heating device is designed as an electric heating rod.The fluid in the pipeline can also be reliably and rapidly heated by means of an electric heating rod and, if appropriate, consolidations can be liquefied again. The electrical heating rod can also be designed in the form of a heating lance that can be pushed into the pipeline.In a further development of the invention, the heating device is provided with swirl plates.By providing swirl plates on the heating device, a heat transfer between the pipeline and the fluid to be cooled on the one hand and also between the heating device and the fluid on the other hand can be improved. On the one hand, this ensures better cooling and, on the other hand, also more rapid heating if the risk of solidifications within the pipeline is imminent.In a further development of the invention, the swirl plates are arranged between the legs of the heating line running in a U-shape.In this way, a very good heat transfer between the swirl vanes and the heating line and at the same time a mechanically very stable fastening of the swirl vanes to the heating line can be ensured. The swirl vanes are thereby heated together with the heating conduit and, if necessary, provide rapid heating of the fluid within the conduit to prevent solidification.In a further development of the invention, the swirl plates are directed at an angle between 30° and 60°, in particular 45°, against the flow of the fluid in the pipeline.Such an arrangement of the swirl vanes has proven to be particularly advantageous since a good heat transfer between the pipeline and the fluid on the one hand and also between the heating line and the swirl vanes and the fluid on the other hand can thereby be ensured.In a further development of the invention, the swirl plates are welded to the heating line or are formed integrally with the heating line.In this way, a very good heat transfer between the heating line and the swirl vanes can be achieved with simultaneously stable mechanical fastening.In a further development of the invention, the plurality of rectilinear sections are arranged one above the other in a plurality of layers in the cooling space, wherein at least one layer is formed from at least two rectilinear tube sections arranged next to one another, and wherein the tube sections of adjacent layers are arranged offset with respect to one another.In this way, on the one hand, a very space-saving arrangement of the rectilinear sections of the pipelines can be achieved and, on the other hand, an arrangement which is very advantageous for the flow of cooling air or coolant perpendicularly to the rectilinear pipe sections can be selected. This is because such an arrangement prevents the straight pipe sections from being arranged in the wind shadow of other pipe sections. As a result, a very good and uniform cooling effect of the cooling air or of the coolant can be achieved on all pipe sections.In a further development of the invention, the pipeline is provided at least in sections with cooling ribs on its outer side.In this way, a heat transfer between the cooling medium and the pipeline can be improved.In a further development of the invention, the cooling medium is air.Air as cooling medium is usually present without problems and it is not absolutely necessary to ensure a closed circuit of the cooling medium.In a further development of the invention, the heating line is supplied with hot water or water vapor.According to the invention, the heating line is activated only when there is a risk of solidifications within the pipeline. In this case, a rapid heating of the fluid is advantageous in order to rapidly leak the risk of solidifications or to quickly melt solidifications already formed. The use of hot water or hot water vapor can ensure such rapid heating of the heating lines.In a further development of the invention, the pipeline is provided with at least one flange for fastening a flange of the heating device.In this way, the heating device, which is advantageously designed as a heating lance, can be mounted in a particularly simple manner. For example, the flange of the pipeline is provided as an extension of a straight pipe section, so that the heating device can be inserted without problems.The problem underlying the invention is also solved by a method for cooling a fluid solidifying in a predefined temperature range, in particular a melt, in which the steps of conducting the fluid through at least one pipeline of a cooler, wherein the pipeline is surrounded by a cooling medium, and detecting a temperature of the fluid in the region of the pipeline, and heating the fluid in the pipeline by means of a heating device which is arranged within the pipeline when the fluid in the region of the pipeline falls below a predefined temperature, are provided.According to the invention, the heating device is therefore only activated when the fluid to be cooled in the region of the pipeline falls below a predefined temperature and there is thus the risk of solidifications within the pipeline. In this way, a fluid, for example a sulphur melt, can be cooled to just above a temperature range in which the sulphur melt then solidifies. This is only possible because the heating device can immediately counter-control and the sulphur melt can be heated again if there is a risk of solidification within the pipeline. The method according to the invention thus makes it possible to cool a fluid, in particular a melt, for example a sulphur melt, to just above the predefined temperature range in which the fluid solidifies. In this way, further processing subsequent to cooling of the fluid can be greatly improved. In the case of a sulphur melt, the pelleting of the sulphur melt in a drop former can thereby be greatly improved.In a development of the invention, the generation of turbulence is provided within the pipeline.The generation of a turbulent flow of the fluid within the pipeline ensures, on the one hand, a good heat transfer between the pipeline and the fluid and, on the other hand, also a good heat transfer between the heating device and the fluid.In a further development of the invention, the heating of swirl plates arranged on the heating device is provided.In this way, the fluid within the pipeline can be heated even more quickly in the event of imminent solidifications, since the surface of the swirl vanes is available for the heat transfer in addition to the surface of the heating device.Further features and advantages of the invention are evident from the claims and the following description of preferred embodiments of the invention in conjunction with the drawings. Individual features of the different embodiments can be combined with one another in any desired manner without exceeding the scope of the invention. In the drawings, there are shown: FIG. 1 shows a view of a device according to the invention in accordance with a first embodiment obliquely from above, FIG. 2 is a side view of the device of FIG. 1, FIG. 3 is a plan view of the sectional plane A-A in FIG. 2, FIG. 4 is a view of the device of FIG. 1 in a partially disassembled state, FIG. 5 shows a view of a heating lance for the device of FIG. 1 obliquely from above, FIG. 6 shows a top view of a second heating lance for the device of FIG. 1, FIG. 7 is a top view of the heating lance of FIG. 5, FIG. 8 is a side view of the heating lance of FIG. 5; and FIG. 9 shows a schematic illustration of an arrangement for granulating sulfur using the cooling device according to the invention.FIG. 1 shows an apparatus 10 according to the invention for cooling a fluid, in particular a sulphur melt. However, the device 10 can also be used, for example, for other melts or also other fluids which solidify within a predefined temperature range. Examples of other fluids are, for example, mixtures of solids and liquids, so-called slurries.The device 10 has a cooling chamber 12 which is bounded by side walls and a base and a cover. The base and the cover each have an air inlet opening 14 or 16, through which cooling air is conveyed through the cooling chamber 12. Fans for conveying the cooling air are not shown in FIG. 1 for the sake of clarity.A fluid to be cooled, for example a sulphur melt, is introduced into an inlet end 18 of a pipeline 20 which runs in meandering fashion and ends at an outlet end 22. The pipeline 20 has a plurality of straight sections which are arranged inside the cooling space 12 and a plurality of deflections 24 which are arranged outside the cooling space 12. Within the cooling chamber, the straight sections of the pipeline 20 are provided with cooling ribs 26 in order to ensure good heat transfer between the cooling air in the cooling chamber 12 and the pipeline 20.Inserted into the straight sections of the pipeline 20 are respective heating lances 28 which can be seen only in sections in the illustration of FIG. 1 and which are fed with superheated steam. The superheated steam is fed into the heating lances 28 via pipelines 30. Only a part of the pipelines 30 which are connected to a steam circuit, not shown, is shown.The device 10 is intended to cool a fluid, in particular a sulphur melt or other melts, down to a temperature which is only slightly above a temperature range in which the fluid or the melt solidifies. This cooling of the fluid is effected by means of the cooling air conveyed through the cooling space 12. Due to the cooling down to immediately above the temperature range in which the fluid solidifies, there is the risk that the fluid already solidifies in the pipeline 20 and this is thereby blocked or, in the partially solidified state, is supplied to a post-processing, for example a pelletization. In order to avoid this and thereby enable the cooling of the fluid to directly above the temperature range in which the fluid solidifies, the heating lances 28 are provided. A temperature of the fluid is measured at the inlet end 18 of the tubing 20 as well as at the outlet end 22 of the tubing. There are provided flanges 32 and 34, respectively, into which a temperature sensor can be inserted. If the temperature at the outlet end 22 falls below a predefined value, a control, not shown, recognizes that there is the risk of solidifications in the pipeline 20. In this case, the pipelines 30 and thus the heating lances 28 are subjected to superheated steam in order to raise the temperature of the fluid within the pipeline 20, in order to thereby create the risk of solidifications and also in order to re-liquify any solidifications which have already formed.By providing heating lines within the pipeline 20 or the heating lances 28, the device 10 according to the invention can therefore be operated in such a way that a temperature of the fluid, in particular of a sulphur melt, at the outlet end 22 of the pipeline 20 lies directly above a temperature range in which the fluid solidifies. Using the example of a sulphur melt, it is possible with the device 10 according to the invention to cool the sulphur melt at the outlet end 22 to a temperature of 125 °C. This is possible with the device 10 according to the invention, although the solidification temperature or solidification temperature of sulfur is in a range between 117° C. and 119° C. A temperature of the sulphur melt of 125 °C is optimal in order to subsequently pellet the sulphur melt by means of a drop former.The illustration of FIG. 2 shows the device 10 according to the invention in a side view. It can be seen that the deflections 24 of the pipeline 20 are arranged outside the cooling chamber 12, see also FIG. 3. The U-shaped deflections 24 arranged on the left in FIG. 2 are in each case flanged to rectilinear sections of the pipeline 20, so that they can be removed in a simple manner for cleaning or inspection purposes. Within the cooling chamber 12, therefore, only straight sections of the pipeline 20 are arranged. Overall, the pipeline 20 runs in meandering fashion, wherein, as explained, only the rectilinear sections of the pipeline 20 are arranged within the cooling space 12.In the illustration of FIG. 2, the pipelines 30 can be seen which serve for supplying hot steam or hot water to the heating lances 28.The illustration of FIG. 3 shows a plan view of the sectional plane A-A in FIG. 2 It is possible to see a part of the pipeline 20, especially the part which adjoins the inlet end 18 of the pipeline. Starting from the inlet end 18, the fluid to be cooled is first deflected by 90° and reaches a first rectilinear section 36 of the pipeline 20, this rectilinear section 36 being arranged in the cooling space 12 and being provided on its outer periphery with cooling ribs 26. Starting from the straight section 36, the fluid then reaches the deflection 24, is deflected by 180° and from there reaches a further straight section 38 of the pipeline 20, which is likewise provided with cooling ribs 26 on its outer circumference. Outside the cooling chamber 12, the fluid is then deflected upward, i.e. out of the plane of the drawing, see also FIG. 2, which, however, is not recognizable in FIG. 3.A first heating lance 40 can be seen within the rectilinear section 36 and a further heating lance 42 can be seen within the rectilinear section 38. The heating lances 40, 42 each have a plurality of swirl plates 44 and 46 spaced apart from one another. The heating lances 40, 42 differ in the arrangement of the swirl vanes 44, 46. Specifically, the swirl vanes 44 of the heating lance 40 are oriented at an angle α against the flow which runs in the rectilinear section 36 in FIG. 3 from right to left. This angle α is advantageously between 30° and 60°, in particular 45°. The swirl vanes 44 ensure swirling of the fluid within the section 36 of the pipeline 20, in particular turbulent flow of the fluid within the section 36, and as a result, the heat transfer between the section 36 of the pipeline 20 on the one hand and also between the heating lance 40 or the swirl vanes 44 and the fluid on the other hand is improved.The swirl vanes 46 of the heating lance 42 are also directed against the flow which runs in the section 38 of the pipeline 20 from left to right in FIG. 3. The angle β, which, like the angle α, is measured counter-clockwise with respect to the respective heating lance 40, 42, is however in this case between 120° and 150°, in particular 145°. As a result, however, the fluid impinges on the swirl plates 44, 46 at an angle between 30° and 60°, in particular 45°, both in the section 36 and in the section 38 of the pipeline 20.FIG. 3 also shows that the pipe 20 is provided with flanges 48 and 50 in the area located outside the cooling chamber 12. The flanges 48 are situated to the right of the cooling chamber 12 in FIG. 3, the flanges 50 to the left of the cooling chamber 12 A straight section 36, 38 of the pipe 20 is situated in each case between the flanges 48, 50.Matching flanges 52 and 54 of the heating lances 42 and 40 can be fastened to the flanges 48. It is thereby possible to make the heating lances 40, 42 straight and these can be easily inserted into the pipeline 20 and fastened there.The flanges 50 serve for fastening the deflections 24.Once the deflections 24 have been removed and the heating lances 40, 42 have also been removed from the pipeline 20, this can be serviced, in particular cleaned, in a particularly simple manner.The illustration of FIG. 4 shows the device 10 of FIG. 1 in a partially disassembled state. Specifically, the side walls as well as the cover and the bottom of the cooling chamber 12 are removed and the pipeline 30 and the heating lances 28 are also not shown. Within the cooling chamber 12, a total of 10 straight sections of the pipeline 20 are arranged, wherein all these straight sections are provided with cooling ribs 26. Viewed from bottom to top, two rectilinear sections are arranged in the lowermost layer, and three rectilinear sections are arranged next to one another in the layer which follows. Two straight sections follow this again, and at the top three straight sections of the pipeline 20 are again arranged horizontally next to one another. This arrangement is thus characterized in that the straight sections of the pipeline 20 are arranged offset one above the other. The cooling air can thereby pass around the straight pipe sections or between the cooling ribs 26, so that a very good heat transfer between the cooling air and the cooling ribs 26 is ensured. The straight sections of all layers are connected in series to one another. This results in a single, non-branched flow path through the cooling chamber 12.As can be seen from FIG. 4, only the rectilinear sections of the pipeline 20 are arranged within the cooling space 12, whereas the deflections 24 are arranged in each case outside the cooling space 12.The illustration in FIG. 5 shows the heating lance 40 from FIG. 3, the heating lance 40 has the flange 54 with which it is fastened, see FIG. 3, to the flange 48 of the pipeline 20. The heating lance 40 has a U-shaped heating line 60 which has two limbs spaced apart from one another. The swirl plates 44 are arranged between the legs of the heating line 60, which, as has already been explained, are directed against the flow. The heating line 60 is provided at the free end of each of its two legs with a connecting flange 62. The connector flanges 62 are connected to the tubing 30, see Figs. 1 and 2, to provide hot water or hot steam to the heating conduit 60.The illustration of FIG. 6 shows a plan view of the heating lance 42 from FIG. 3. The swirl vanes 46, like the swirl vanes 44 of the heating lance 40, are arranged between the legs of the heating line 60 and are welded or soldered to the latter, for example. Only the angle which the swirl vanes 44 and 46 enclose with the respective heating line 60 differs, so that the swirl vanes 44, 46 are always directed against the flow of the fluid in the associated section of the pipeline 20.The illustration of FIG. 7 shows the heating lance 40 of FIG. 5 from above.FIG. 8 shows the heating lance 40 of FIGS. 5 and 7 from the side. It can be seen in this view that the swirl plates 44 are arranged between the legs of the heating line 60. The swirl vanes 44 are soldered or welded to the heating line 60, for example, so that a good heat transfer is present between the heating line 60 and the swirl vanes 44. The swirl vanes 44 and the swirl vanes 46 of the heating lance 42 thereby serve not only to generate a swirling flow in the pipeline 20, but at the same time also to transfer the thermal energy of the heating line 60 to the fluid flowing in the pipeline 20.The illustration of FIG. 9 schematically shows an apparatus 162 for granulating sulfur. The apparatus 10 according to the invention for cooling a sulphur melt is part of this device 162. A sulphur melt is provided by an apparatus 64, which is not further detailed in FIG. 9. This sulphur melt has a temperature of about 150° C. The sulphur melt is conveyed by a pump 66 to the device 10 according to the invention. A temperature of the sulphur melt of 150° C. is too high for optimum operation of a granulating device 68. A temperature of the sulphur melt of 125 °C is optimal in order to be able to ensure a good quality of the pellet and a high throughput of the pelleting device 68. The sulphur melt is therefore passed over the apparatus 10 in order to cool the sulphur melt to a temperature of 125 °C. A temperature of the sulphur melt upstream of the device 10 is detected at a point 70 upstream of the device 10 and at a further point 72 downstream of the device 10. As already described, the device 10 has the cooling chamber 12 through which the pipeline 20 is guided. Cooling air is conveyed through the cooling chamber 12 from bottom to top in FIG. 9 by means of a blower 74. The fan 74 is driven by a motor 76 and draws in the cooling air via an air filter 78. Above the cooling chamber 12 a flap 80 is arranged, with which a cooling air flow through the cooling chamber 12 can be reduced or shut off, if necessary.As has already been discussed, heating lances are arranged in the rectilinear sections of the pipeline 20, with which the sulphur melt within the pipeline 20 can be heated if appropriate. A supply of superheated steam to these heating lances or the removal of the superheated steam from the heating lances is indicated merely schematically in FIG. 9 by the arrows 82, 84. The exact structure of the heating lances and of the pipeline 30 for supplying hot steam or hot water has already been described with reference to FIGS. 1 and 2.Downstream of the apparatus 10, the sulphur melt, which is now cooled to a temperature of 125 °C, is conveyed by means of a further pump 86 to a drop former 88. The pump 86 is not absolutely necessary and can also be omitted. The drop former 88 has a rotating, perforated outer drum 90 and a nozzle strip 92 which bears against the inner side of the outer drum 90. The molten sulfur is pressed against the rotating outer drum 90 by the nozzle strip 92, so that droplets of the molten sulfur are produced by the rotating outer drum 90. These droplets of sulphur melt are deposited on a revolving steel belt 94 which revolves in the direction of the arrow 96 around two drums 98 and 100, respectively. Heating channels 102 are provided within the drop former 88 in order to maintain the drop former 88 and, in particular, the sulphur melt located therein at a temperature of approximately 125°, in order thus to prevent the sulphur melt from already solidifying within the drop former 88.The molten sulfur droplets deposited on the steel belt 94 solidify on the steel belt 94 while being transported further on the upper run of the steel belt 94 from left to right in FIG. 9. For this purpose, the steel strip 94 is cooled from below by means of spray nozzles 104 and 106. On the deflection drum 100 on the right in FIG. 9, the sulfur melt droplets are consolidated into pastilles and can be removed from the steel strip 94 by means of a removal knife 108 in the region of the deflection drum 100 and are then supplied, for example packaged, according to an arrow 110 to a further processing. A hood 112 is disposed above the drop former 88 and above the steel strip 94 to assure constant temperatures above the steel strip 94.Since the sulfur melt is supplied to the drop former 88 at a temperature of 125 °C, it can operate in the optimum temperature range and the pelletizer 68 can be operated at a high throughput and at the same time a very good pellet quality can be obtained.In order to prevent clogging of the device 10 and yet to be able to supply the sulphur melt at a temperature of 125 °C to the drop former 88, the temperature is detected at least at the location 72 downstream of the device 10 in the pipeline 20. If the temperature of the sulphur melt at the point 72 falls below a predefined temperature value, for example 125 °C, a control, not shown, causes the heating lances in the pipeline 20 to be acted upon with heating vapour in order to bring the sulphur melt within the pipeline 20 back as quickly as possible to a temperature at which no solidifications within the pipeline 20 need to be feared. At the same time, the control, which is not shown, can also influence, for example, a cooling air quantity by actuating the motor 76 of the blower 74 and / or by adjusting the flap 80. The advantage of the heating lines provided according to the invention within the pipeline 20, however, is that, on the one hand, a very rapid control of the temperature of the sulphur melt in the pipeline 20 can be achieved and that even consolidations which have already occurred can be melted again within the pipeline 20.The apparatus 10 according to the invention for cooling a sulphur melt is surrounded by a dashed line in the illustration of FIG. 9. This is intended to indicate that the device 10 forms a module which can be separated from the device 162. It is indeed possible to provide a higher-order process computer for controlling the device 162, which then also assumes the control or regulation of the device 10. In the embodiment shown, however, the device 10 is provided with its own central controller 120, which ultimately controls or regulates the operation of the device 10 and ensures that a fluid flowing into the device 10 leaves the device 10 again at a predefined temperature.For this purpose, the controller 120 receives input signals from the temperature sensors 70, 72. The controller 120 processes these temperature signals and controls, in dependence on these temperature signals, the motor 76 which acts on the cooling air blower 74. In addition, the controller 120 also controls the flap 80 on the downstream side of the cooling room 12. As a result, a cooling air flow through the cooling space 12 can be controlled with the controller 120 as a function of the temperatures detected by means of the temperature sensors 70, 72. In normal operation, the temperature at the sensor 72, i.e. at the outlet of the device 10, is controlled only by means of a change in the amount of cooling air which flows through the cooling space 12, i.e. by means of a setting of the motor 76 and the flap 80. Only when the temperature detected by the sensor 72 falls below a predefined temperature is a heating device activated in the pipeline in the cooling space 12, which heating device can have electrical heating rods or heating lances as have been described in connection with the exemplary embodiment of FIGS. 1 to 8. These heating lines, which are designed in the form of heating lances, are subjected to superheated steam, as is indicated merely schematically in FIG. 9 by means of the arrows 82, 84. Superheated steam is likewise supplied by controlling the central controller 120, the valves and other means required for this purpose not being shown in FIG. 9 for the sake of clarity.However, by providing the central controller 120, the invention provides a device 10 which can be used as a module and which does not require a superordinate process computer for providing a fluid having a predefined temperature at its output.

Claims

Device for cooling a fluid solidifying in a predefined temperature range, having a cooling space (12) for receiving or passing a cooling medium through, at least one pipe (20) for the fluid, which pipe is arranged at least in sections within the cooling space (12), wherein the pipe (20) runs in a meandering manner and has a plurality of rectilinear sections (38, 36) guided through the cooling space (12), and wherein at least one heating device arranged within the pipe (20) is provided.Device according to claim 1, characterised in that the heating device is designed as a heating line (60).Device according to claim 2, characterised in that the heating line (60) extends in a U-shaped manner and is constructed as a heating lance (28, 40, 42) which can be pushed into the pipeline (20).Device according to claim 1, characterised in that the heating device is designed as an electric heating rod.Device according to at least one of the preceding claims, characterized in that the heating device is provided with swirl plates (44, 46).Device according to claim 2 or 3 and 5, characterised in that the turbulence plates (44, 46) are arranged between the limbs of the heating line (60) running in a U-shape.Device according to claim 5 or 6, characterised in that the turbulence plates (44, 46) are arranged such that the fluid impinges on the turbulence plates (44, 46) at an angle between 30 degrees and 60 degrees, in particular 45 degrees.Device according to claim 5, 6 or 7, characterised in that the turbulence plates (44, 46) are welded, soldered or formed integrally with the heating device.Device according to at least one of the preceding claims, characterized in that the fluid is a melt.Device according to claim 9, characterised in that the plurality of rectilinear sections (36, 38) are arranged in the cooling space (12) in a plurality of layers one above the other, wherein at least one layer is formed from at least two rectilinear tube sections (36, 38) arranged next to one another, and wherein the tube sections of adjacent layers are arranged offset with respect to one another.Device according to at least one of the preceding claims, characterized in that the pipeline (20) is provided at least in sections with cooling ribs (26) on its outer side.Device according to at least one of the preceding claims, characterized in that the cooling medium is air.Device according to at least one of the preceding claims, characterized in that the heating device is designed as a heating line (60) and the heating line (60) is fed with hot water or steam.Device according to at least one of the preceding claims, characterized in that the pipeline (20) is provided with at least one flange (48) for fastening a flange (52, 54) of the heating device.Method for cooling a fluid solidifying in a predefined temperature range, comprising the steps of conducting the fluid through at least one pipeline (20) of a cooling device, wherein the pipeline (20) runs in a meandering manner and has a plurality of rectilinear sections (38, 36) conducted through a cooling space (12), and wherein the pipeline (20) is surrounded by a cooling medium, and detecting a temperature of the fluid in the region of the pipeline (20), and heating the fluid in the pipeline (20) by means of a heating device which is arranged within the pipeline (20) if the fluid in the region of the pipeline (20) falls below a predefined temperature.A method according to claim 15, characterised bybubbling turbulence within the pipe (20).Method according to claim 15 or 16, characterised by swirl vanes (44, 46) arranged on the heating device.Method according to one of claims 15, 16 or 17, characterised in that the fluid is a melt.

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