JP2004012061A - Continuous cooling method for divided solid and implementing device for method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous cooling technique for divided solids capable of effectively cooling divided solids that are extremely variant in regard to particle size. <P>SOLUTION: In the present invention, a center zone of a mass M of the divided solids is constantly cooled by convection by passing over a cooling wall 111 extending in a conveying direction. At the same time, a dry cold air current 120 is sent through the mass of divided solids. The cold air current fluidizes the mass without condensation, and it serves as to increase a heat exchanging coefficient of the cooling wall. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for continuous cooling of divided solids.
[0002]
[Prior art]
In particular, in the agricultural products processing industry, a divided solid conveying device and a heat treatment device which can take the shape of a bulk material or a powder material are already known. These are those in which the treated divided solids are discharged at a relatively high temperature, often at very high humidity, from the latter stage of the heat treatment apparatus.
[0003]
[Problems to be solved by the invention]
For this reason, it is necessary to cool the treated divided solid, and the cooling technique is preferably performed directly downstream of the heat treatment system.
A number of cooling techniques are already known and will be briefly described below, but none of these techniques seem to be able to satisfactorily perform a continuous cooling process that is both effective and economically feasible. It is.
[0004]
Thus, fixed bed cooling techniques based on the principle of vertical countercurrent circulation of product and cold air are known. This type of technology has the advantage of being economical and suitable for cereals. However, this is a discontinuous technique and is not suitable for the treatment of low solids fractionated solids, such as powdered products or very fine products.
[0005]
Fluidized bed technology based on the principle of circulation of a sufficiently large amount of cold air to fluidize a cooled product is also known. In terms of heat, of course, fluidization is very preferable, and it is known that the heat exchange coefficient is greatly improved. However, this type of technology has the disadvantage of requiring a very high air flow rate and requires a downstream device, such as a dust collector or a sleeve filter, to prevent the release of fine particles into the atmosphere. Furthermore, this technique has difficulties in controlling the dwell time and is still not suitable for continuous cooling.
[0006]
Cold air drum technology based on the principle of passing the product through a directly or indirectly cooled rotating cylinder can also be mentioned. The drum is optionally tiltable and / or rotatable and may include an internal propeller. The advantage of this type of technology lies mainly in its versatility. This technique is suitable for all types of loose products and allows very high flow rates. However, this technique is bulky and expensive to manufacture.
[0007]
In addition, a vibrating fluidized bed technology based on the principle of horizontal vibration transport with a passage through a cold air bucket is also known. Thus, the cool air fluidizes the divided solids at the same time as cooling, so that a very appropriate heat exchange coefficient is obtained. However, this technique requires a very high air flow rate and requires a dust control device at a later stage. Therefore, although it is very effective for products that are not in powder form, the production cost is still high.
[0008]
In addition, reference can be made to the double arm screw technology, based on the principle of a feed screw rotating in a bucket with two armors. The wall constituting the double exterior is a non-hollow wall that defines a space in which the refrigerant fluid circulates. This type of technology is suitable for all kinds of products. This technique has the advantage that the stagnation time is relatively well controlled and the particles do not scatter unless air is blown at all. However, this technique has high production costs and relatively low heat exchange rates, resulting in very long dwell times. This is particularly detrimental if it is desired to cool the very humid split solids at the output of the heat treatment plant. This is because, in that case, the risk of condensation of the product as the temperature is lowered is particularly high. Such condensation is undesirable as it generally forms more or more agglomerates or agglomerates of the product.
[0009]
The object of the present invention is to constitute a continuous solid cooling technology for divided solids which can effectively cool a wide variety of types of divided solids in terms of particle size without having the disadvantages or limitations mentioned above and under very favorable economic and dimensional conditions. It is in.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention provides a method for continuously cooling divided solids, wherein the divided solid mass (M) is stirred, transported in a predetermined direction (X), and divided. The central zone of the solid mass (M) is constantly cooled by convection by passing over a cooling wall (111) extending in the transport direction (X), and at the same time, the dry cold air flows into the divided solid mass. Through (120), the cold air flow serves to increase the heat exchange coefficient of the cooling wall while fluidizing the mass without condensing the mass.
[0011]
Also, the cooling wall is composed of a hollow shaft (111) system of at least one screw (110) serving to agitate and transport the divided solid mass (M), and a coolant fluid flows through the inside of the shaft. As such, it is preferred that the dry cold airflow (120) passing through the mass be organized in a substantially lateral direction toward the hollow shaft (111).
Furthermore, it is preferred that the dry cold airflow (120) through the divided solid mass is subdivided in the transport direction, and that the temperature and / or humidity characteristics are variable, possibly depending on the cross section.
Furthermore, it is preferred that the dry cold air stream (120) is blown into the divided solid mass (M).
Further, it is preferable that the dry cold airflow (120) is sucked from the divided solid mass (M).
[0012]
Furthermore, an elongate bucket (12) and an elongate bucket (12) comprising a U-shaped double outer shell, wherein the inner outer shell (14) is at least partially gas permeable while allowing the divided solid to be treated to be fixed. A blower or intake means (113) communicating with the inner space (15) of the heavy exterior, and at least one drive screw (110) arranged on the bucket (12) of the double exterior, comprising one or each screw (110); 110) is preferably hollow and the refrigerant fluid flows inside.
7. The device according to claim 6, wherein the inner shell (14) of the elongate bucket (12) comprises at least one substantially semi-cylindrical grid member.
[0013]
It is also preferred that at least one grid member (14) has on its outer surface at least one cooling section (136) that partitions the interior space (15) of the double exterior of the elongated bucket (12).
Further, the outer jacket (13) of the elongate bucket (12) is comprised of at least one housing member that is substantially semi-cylindrical, such that the housing member accesses the inner jacket (14) of the elongate bucket from outside. It is preferably mounted in a swingable manner about a longitudinal axis (135).
Furthermore, a wide container (16) covered with a cover (17) is mounted on the elongate bucket (12), and an opening (18) for receiving a processed product is provided at one end of the cover (17). Is preferred.
[0014]
It is also possible that the blowing or suction means (123) is coupled on the wall of the wide container (16) to the opposite side of the blowing or suction means (113) which is strictly coupled to the elongated bucket (12). preferable.
Furthermore, it is preferred that the ventilation or intake means (113, 123) comprises a plurality of joints (115, 125) distributed along the length of the elongated bucket (12).
Furthermore, it is preferable that the ventilation and intake means (113, 123) are connected by a recirculation path (130) including a dehumidifier (132).
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the present invention, this problem is solved by a method for continuous cooling of divided solids, wherein the divided solid mass is stirred and transported in a predetermined direction, and the central zone of the divided solid mass is It is constantly cooled by convection by passing over a cooling wall extending in the transport direction, and at the same time, a dry cold air flow is passed through the divided solid mass, and the cold air flow fluidizes the mass without condensing. In addition, it serves to increase the heat exchange coefficient of the cooling wall.
[0016]
Thus, an air stream is used to fluidize the divided solid mass to be cooled. Further, the airflow enhances the heat exchange rate of the cooling wall while promoting the convection of the product. The airflow is also dry so that the cooling product does not condense, and in fact, the two functions of the airflow greatly improve efficiency.
[0017]
Preferably, the cooling wall comprises at least one threaded hollow shaft system serving to stir and transport the divided solid mass, through which the coolant fluid passes and passes through the mass. A stream of dry cold air is organized approximately laterally toward the hollow shaft.
[0018]
According to a particular embodiment of the method, the dry cold air flow through the divided solid mass is subdivided in the transport direction and the temperature and / or humidity properties are variable, possibly depending on the cross section. This creates a cooling zone with variable characteristics depending on the location of the split solids along the length of the elongate bucket, allowing for more sophisticated cooling.
[0019]
The dry cold air stream can be blown into the divided solid mass and, in an alternative embodiment, can be sucked from the divided solid mass.
[0020]
The present invention also relates to a cooling device for performing the cooling method. According to the invention, the cooling device comprises a U-shaped double jacket, wherein the inner jacket is at least partially gas-permeable while allowing the divided solids to be treated to be fixed, and a double bucket of elongated buckets. It includes a ventilation or intake means communicating with the interior space of the exterior, and at least one drive screw arranged in a double exterior bucket, wherein one or each screw is hollow and through which the refrigerant fluid flows.
[0021]
Preferably, the inner jacket of the elongate bucket is composed of at least one substantially semi-cylindrical grid member. This structure facilitates the disassembly and assembly operation.
In that case, at least one grid member can be configured to have, on its outer surface, at least one cooling section that partitions the internal space of the double jacket of the elongated bucket. With such partitioning, as described above, it is possible to realize a method of subdividing the dry and cool airflow in the transport direction.
[0022]
According to a preferred embodiment, the outer jacket of the elongate bucket is comprised of at least one housing member that is substantially semi-cylindrical, the housing member having a longitudinal extension so as to access the inner jacket of the elongate bucket from the outside. It can be mounted swinging around an axis. Swinging in the outer jacket of the elongate bucket by swinging is, in fact, very advantageous. This is because the grid member constituting the inner casing can be immediately accessed, so that cleaning can be performed very easily without touching the feed screw.
[0023]
More preferably, a wide container covered with a cover is mounted on the elongated bucket, and one end of the cover is provided with an opening for receiving the processed product.
In that case, preferably, the blowing or suction means is connected in the wall of the wide vessel to the opposite side of the blowing or suction means which is strictly connected to the elongated bucket.
Preferably, the blowing or intake means comprises a plurality of joints distributed along the length of the elongated bucket. In that case, the ventilation and intake means can be configured to be connected by a recirculation path including a dehumidifier.
[0024]
Other features and advantages of the present invention will become apparent from the following description of specific embodiments, which proceeds with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view of a cooling device using the method of the present invention.
FIG. 2 is a cross-sectional view showing a modified embodiment of the device, in which the air supply means is connected by a circulation path.
FIG. 3 is a perspective view of the apparatus of FIG. 1 with the closure cover partially removed to show the grid member and the lead screw.
FIG. 4 is a cross-sectional view similar to FIGS. 1 and 2 showing an alternative embodiment of the device with two feed screws juxtaposed.
FIG. 5 is a partial perspective view showing a swing assembly of a housing member constituting an outer sheath of the elongated bucket, and a swing position for accessing the inner sheath from the outside is indicated by a broken line.
FIG. 6 is a partial perspective view, similar to FIG. 5, showing the cooling zone of the grid member forming part of the inner jacket of the elongated bucket, with the outer jacket of the elongated bucket partially removed.
[0025]
FIG. 1 shows a cooling device 11 for continuously cooling the divided solids. The split solid can take the form of a loose solid or a powdered solid.
[0026]
The cooling device 11 first includes an elongated bucket 12 with a U-shaped double armor. The outer sheath 13 of the elongate bucket 12 preferably comprises at least one housing member that is substantially semi-cylindrical. As will be described, each housing member is preferably pivotally mounted about a longitudinal axis 135 to provide external access to the inner exterior of the elongated bucket 12. The inner shell of the elongate bucket 12 is at least partially gas permeable while allowing the divided solids to be treated to be fixed. Preferably, the inner shell 14 of the elongate bucket 12 is comprised of at least one substantially semi-cylindrical grid member. The term "grid" as used herein is to be interpreted in a broad sense and includes perforated steel sheets and sintered parts, or also metal or synthetic fabrics. In general, the dimensions of the openings in the grid are such as to allow a flow of cool air while fixing the divided solids which are collected inside the elongated bucket to form a mass M. As shown, the divided solid mass M completely fills the interior of the elongated bucket, thereby covering the lead screw 110 located on the bucket.
[0027]
Also shown is a ventilation or intake means 113 communicating with the inner space 15 of the double exterior of the elongated bucket 12. This means includes a joint end 114 communicating with a longitudinal tube 118, from which a series of side joints 115 branch off. Each joint 115 includes a valve 116, and the opening and closing of the valve is performed by an operation lever 117 that is connected thereto. In this case, the airflow arriving from the joint 115 is composed of dry cold air entering the internal space 15 as shown by the arrow 119. The dry cool air, of course, passes through the interior space 15, while entering various locations inside the bucket through the inner wall 14 of the bucket. In this way, the airflow 120 is formed inside the divided solid mass M. The speed of the airflow is sufficient to fluidize the product. Inside the elongated bucket 12, a hollow shaft 111 of a drive screw 110 is shown. Here, the hollow shaft 111 is a single hollow shaft and includes radial wings 112. The hollow shaft 111 is a hollow shaft for flowing the refrigerant fluid inside the shaft.
[0028]
Thus, the screw 110 stirs the mass M of the divided solid and conveys it in the axial direction X of the screw 110. Next, in particular, the central zone of the divided solid mass M is constantly cooled by convection passing over the hollow shaft (cooling wall) 111 extending in the transport direction X. At the same time, a dry cold air stream 120 is passed through the divided solid mass. The dry cold airflow serves to fluidize the lumps without condensing and to increase the heat exchange coefficient of the cooling wall.
[0029]
Here again, the cooling wall consists of a hollow shaft 111 system of at least one screw 110, which stirs and transports the mass M of divided solids, inside which the refrigerant fluid flows, and which is dried and cooled through the mass. The airflow 120 is organized substantially laterally towards the hollow shaft 111.
[0030]
As can be seen, a wide container 16 covered by a cover 17 is mounted on the elongate bucket 12, and one end of the cover 17 is provided with an opening 18 for receiving the processed product. In this way, the processed product enters through the receiving opening 18 at one end of the cooling device 11 and exits through the outlet opening 19 at the other end, which is perforated in the outer wall 13 of the elongated bucket 12. The presence of a wide vessel 16 with a wide cross section is advantageous here, because the widening of the cross section slows down the speed of the particles. In any case, the cover 17 keeps some particles from scattering outside the device.
[0031]
Furthermore, it is effective to carry out air recovery. The recovery of the air takes place here by means of suction 123 which is connected to the side wall of the wide vessel 16, preferably on the opposite side of the blowing means 113 which is connected in a strict sense to the elongated bucket 12. The suction means 123 has a structure similar to that of the air blowing means 113, and the same reference numeral with the addition of 110 indicates a joint end 124 that communicates with the longitudinal cylinder 128. A plurality of side joints 125 protrude from the longitudinal tube, and each joint 125 includes a valve member 126 with an operating handle 127. Inspiration is indicated by arrow 129.
[0032]
As shown here, the dry cold airflow 120 is sent to the divided solid mass M by the blowing means 113. However, the method according to the opposite variant can also be implemented. In this variant embodiment, a dry cold air stream 120 is sucked from the mass M of divided solids. In this case, the suction means 123 changes to a blowing means, and the blowing means 113 changes to a suction means. In practice, as long as the structural member can stay in place, this method is easy to implement and only requires the fluid divergence to be changed at the two joining ends 114,124.
[0033]
The general structure of the cooling device 11 can be better understood from the perspective view of FIG. There is an end of the screw 110 protruding from the hollow shaft 111, which serves to connect to a circulation path (not shown) of a coolant fluid such as, for example, glycol water or a suitable cold gas. At the other end of the elongate bucket 12 is also shown an electric speed reducer 150, the output of which is coupled to the hollow shaft 111 of the screw 110 by a transmission housed in a housing 151 to which it is coupled. In this case, the electric reduction gear device 150 is eccentric because the space in the axial direction is filled to circulate the refrigerant fluid inside the hollow shaft 111 of the screw 110.
[0034]
FIG. 2 is a view similar to FIG. 1 and shows a modified embodiment of the above-described device in which the blowing means 113 and the suction means 123 are connected by a recirculation path 130. The recirculation path 130 includes a tube 131 to which a dehumidifier 132 is connected. In some cases, the recirculated air can be between 80 and 100%, with the balance made up of fresh air taken from the dehumidifier. FIG. 2 also shows a method according to an alternative embodiment, in which a dry cold air stream 120 is sucked from a mass M of divided solids. This variant embodiment has already been described.
[0035]
FIG. 4 shows another modified embodiment in which the cooling device 11 has two drive screws 110 juxtaposed in a common bucket 12 with a double armor, each screw 110 having a hollow shaft 111. Then, the refrigerant fluid flows inside the screw. Therefore, the outer wall 13 and the inner wall 12 of the elongated bucket 12 are common to the two drive screws 110. Therefore, this principle is the same as that of the previous embodiment, and has a structure symmetric with respect to the center plane P. Further, the corner members 133 are arranged from the bottom of the grid wall 13. This corner member can prevent products that are not agitated by the wings 112 of the drive screw 110 from stagnating. The cooling process is the same as that performed in the previous equipment.
[0036]
As shown in FIG. 5, the outer casing 13 of the elongate bucket 12 comprises at least one substantially semi-cylindrical housing member, the housing member comprising a hinge provided on the side of the longitudinal axis 135. By 134, it is attached so as to swing about this shaft 135. When the corresponding joint is removed at the joint level 115.1, the housing member 13 swings easily about the axis 135 as shown by the broken line in FIG. This makes it possible to access the inner casing, which is made up of grid members, significantly easier, and can be carried out without touching the various parts of the screw, in particular the wings of the screw. The swing is indicated by arrow 1100 in FIG.
[0037]
As shown in FIG. 6, at least one grid member 14 constituting the inner casing of the elongate bucket 12 has at least one cooling section 136 on its outer surface that partitions the internal space 15 of the double outer casing of the elongate bucket 12. . The cooling section 136 is substantially annular, flat, semi-ring shaped and has a radial width that is approximately the same as the internal space 15 defined by the two walls 13, 14 of the double jacket in the elongated bucket 12. Therefore, the dry cold airflow passing through the divided solid mass can be subdivided in the transport direction, and in some cases, the temperature characteristics and / or the humidity characteristics can be changed according to the cross section. In fact, it may be sufficient to provide as many cooling sections 136 as the joints 115 or groups 115, as the case may be.
[0038]
For example, the length for housing member 13 and grid member 14 can be about 2 meters. In that case, the grid member is composed of a semi-cylindrical basket. The basket is bordered at the top by a longitudinal section that is bolted, which section is stiffened by a crown of circular cross section as described above.
[0039]
One or more of the feed screws 110 shown here have separate wings 112 whose shape can break up the agglomerate of the product to be agglomerated. However, it is obvious that the invention is not limited to any particular shape of the wings of the feed screw and may constitute a spiral to be welded.
[0040]
The invention is also not limited to the embodiments described, but, on the contrary, includes equivalent means and any modified embodiments with the main features described above.
[0041]
【The invention's effect】
According to the invention, this problem is solved by a method for continuous cooling of divided solids, wherein the divided solid mass is stirred and transported in a predetermined direction, the central zone of the divided solid mass being: It is constantly cooled by convection by passing over a cooling wall extending in the transport direction, and at the same time, a dry cold air flow is passed through the divided solid mass, and the cold air flow fluidizes the mass without condensing. In addition, it serves to increase the heat exchange coefficient of the cooling wall.
Thus, an air stream is used to fluidize the divided solid mass to be cooled. Further, the airflow enhances the heat exchange rate of the cooling wall while promoting the convection of the product. The airflow is also dry so that the cooling product does not condense, and in fact, the two functions of the airflow greatly improve efficiency.
Preferably, the cooling wall comprises at least one threaded hollow shaft system which serves to stir and transport the divided solid mass, through which the coolant fluid passes and passes through said mass. A stream of dry cold air is organized approximately laterally toward the hollow shaft.
According to a particular embodiment of the method, the dry cold air flow through the divided solid mass is subdivided in the transport direction and the temperature and / or humidity properties are variable, possibly depending on the cross section. This provides a cooling zone with variable characteristics depending on where the split solids are located along the length of the elongate bucket, allowing for more sophisticated cooling.
The dry cold air stream can be blown into the mass of divided solids and, in an alternative embodiment, can be inhaled from the mass of divided solids.
The present invention also relates to a cooling device for performing the cooling method. According to the invention, the cooling device comprises a U-shaped double shell, the inner shell of which is at least partially gas-permeable while allowing the divided solid to be treated to be fixed, and a double of the elongated bucket. Including air blowing or suction means communicating with the interior space of the exterior, and at least one drive screw disposed in the bucket of the double exterior, one or each of the screws being hollow, through which refrigerant fluid flows.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a cooling device using the method of the present invention.
FIG. 2 is a cross-sectional view showing a modified embodiment of the device in which the air supply means is connected by a circulation path.
FIG. 3 is a perspective view of the apparatus of FIG. 1 with the closure cover partially removed to show the grid member and the lead screw.
FIG. 4 is a cross-sectional view similar to FIGS. 1 and 2 showing an alternative embodiment of the device with two feed screws juxtaposed.
FIG. 5 is a partial perspective view showing a swing assembly of a housing member constituting an outer casing of the elongated bucket.
FIG. 6 is a partial perspective view similar to FIG. 5, showing a cooling area of a grid member forming a part of the inner jacket of the elongated bucket, with a portion of the outer jacket of the elongated bucket removed.
[Explanation of symbols]
11 cooling device 110 screw 111 hollow shaft (cooling wall)
112 Wing 113 Air blowing or suction means 114 Joining end 115 Joining section 116 Valve 117 Operating lever 118 Tube 119 Arrow 12 Slender bucket 120 Dry / cool air flow 123 Inhalation means 124 Joining end 125 Side joint 126 Valve member 127 Operating handle 128 Tube 129 Arrow 13 Outer sheath 130 Recirculation path 131 Tube 132 Dehumidifier 14 Inner sheath 15 Internal space 151 Housing 16 Container 17 Cover 18 Receiving opening 19 Outlet opening

Claims (13)

A method for continuously cooling divided solids, wherein the divided solid mass (M) is stirred and conveyed in a predetermined direction (X), and a central zone of the divided solid mass (M) is , Is constantly cooled by convection by passing over a cooling wall (111) extending in the transport direction (X), and at the same time, the divided solid mass is passed through a dry cold air flow (120), and the cold air flow is A method for continuously cooling divided solids, wherein the mass is fluidized without condensing and serves to increase the heat exchange coefficient of the cooling wall. The cooling wall comprises a hollow shaft (111) system of at least one screw (110) serving to stir and transport the divided solid mass (M), through which the coolant fluid passes; The method of any of the preceding claims, wherein the dry cold airflow (120) passing through the mass is organized substantially laterally toward the hollow shaft (111). 2. The method as claimed in claim 1, wherein the dry cold air flow through the divided solid mass is subdivided in the conveying direction and the temperature and / or humidity characteristics are variable, depending on the cross section. 3. The method according to 2. The method according to any of the preceding claims, characterized in that the dry cold air stream (120) is blown into divided solid masses (M). The method according to any of the preceding claims, characterized in that the dry cold air stream (120) is sucked from the divided solid mass (M). An elongated bucket (12) comprising a U-shaped double shell, wherein the inner shell (14) is at least partially gas permeable while allowing the divided solids to be treated to be fixed, and a double shell of the elongated bucket (12). Air or air intake means (113) in communication with the internal space (15) of the vehicle, and at least one drive screw (110) arranged in the bucket (12) with double exterior, one or each screw (110). A cooling device for performing the method according to any one of claims 1 to 5, wherein the cooling medium is hollow and a refrigerant fluid flows therein. 7. The device according to claim 6, wherein the inner sheath (14) of the elongate bucket (12) is composed of at least one substantially semi-cylindrical grid member. 8. The method as claimed in claim 7, wherein the at least one grid element has at least one cooling section on its outer surface that partitions the interior space of the double outer shell of the elongated bucket. The described device. An outer sheath (13) of the elongate bucket (12) is comprised of at least one housing member having a substantially semi-cylindrical shape, the housing member being elongated to access the inner sheath (14) of the elongate bucket from the outside. Device according to one of the claims 6 to 8, characterized in that it is mounted pivotally about a directional axis (135). A wide container (16) covered by a cover (17) is mounted on the elongate bucket (12), and an opening (18) for receiving a processed product is provided at one end of the cover (17). Apparatus according to any one of claims 6 to 9, characterized in that: The blast or suction means (123) is characterized in that it is coupled on the wall of the wide container (16) to the opposite side of the blast or suction means (113) which is strictly connected to the elongated bucket (12). An apparatus according to claim 10, wherein 12. The air supply or intake means (113, 123) comprises a plurality of joints (115, 125) distributed along the length of the elongated bucket (12). The device according to item. Device according to claim 12, characterized in that the ventilation and intake means (113, 123) are connected by a recirculation path (130) comprising a dehumidifier (132).

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