A cooling coil

Abstract

The present invention relates to a cooling coil, which comprises a steel pipe and a fixing plate, and the steel pipe is fixed on the fixing plate through a clamp; the steel pipe is arranged in the shape of a mosquito coil, and is formed by one-time rolling from the inside to the outside, and there is no secondary welding joint in the whole coiled pipe formed by rolling. The cooling coil is mainly applied to a vertical continuous cooling and crystallization device, and its structure is a mosquito coil-shaped coiled pipe structure. The coiled pipe structure is arranged in the shape of a mosquito coil, and is formed by one-time rolling from the inside to the outside. There is no secondary welding joint in the whole coiled pipe, and the quality of the coiled pipe is reliable without any leakage risk.

Description

Technical Field

[0001] The present invention relates to the technical field of cooling crystallization, and particularly relates to a cooling coil of a vertical continuous cooling crystallizer suitable for various materials in the biochemistry industry. Background Art

[0002] In the production technologies of sugar alcohols (such as glucose, sorbitol, mannitol, etc.), amino acid industries (such as sodium glutamate, citric acid, etc.), pharmaceutical industries, etc. using corn, rice or other raw materials, most currently adopt medium and small horizontal cooling crystallizers. Due to the reasons of technical structure, the cooling heat exchange is not sufficient, the materials are easy to leak, and its operation mode is intermittent operation, and continuous crystallization cannot be achieved. The vertical continuous cooling crystallizer is a vertical cylindrical container, and a plurality of cooling discs are sequentially arranged in the shell from bottom to top. The cooling discs are respectively connected to the cooling medium pipelines outside the shell, which can achieve continuous crystallization, improve production efficiency, and maintain stable product quality; its reasonable cooling crystallization structure enables the crystallization process parameters to be conveniently controlled and adjusted, can achieve multi-stage temperature gradient control, and the equipment can be equipped with a computer system to achieve automatic control, saving consumption. In the prior art, the cooling discs of the vertical continuous cooling crystallizer are divided into tube-type cooling discs and disc-type cooling discs. The existing tube-type cooling discs are divided into two forms: polygonal cooling coils and circular cooling coils:

[0003] 1. Polygonal cooling coils. The coils are wound into a polygonal shape by a plurality of straight coils or elbows in a certain order. The lower end of the coil is connected to the cooling medium inlet, and the upper end is connected to the cooling medium outlet. The cooling medium flows in the tube in a certain order, and the material flows downwards outside the tube from top to bottom. With stirring, heat exchange is formed.

[0004] 2. Circular cooling coils. The cooling coils are composed of multiple layers and multiple circles of steel pipes. Each layer of cooling coil is composed of a plurality of concentric circles. The diameter of each circle of cooling coil starts from the center and gradually increases outwards. Each circle of cooling coils is connected into a passage through elbows. According to the cooling process requirements, the cooling coils are correspondingly divided into layers and blocks to form a cooling module. Between the layers, corresponding pipe fittings are used to connect into a passage as needed. The lower end of the pipe is connected to the cooling medium inlet, and the upper end is connected to the cooling medium outlet. The cooling medium flows in the tube in a certain order, and the material flows downwards outside the tube from top to bottom. With stirring, heat exchange is formed.

[0005] For the polygonal cooling coils, since the coils are spliced into a polygonal shape by straight pipes or elbows through welding, and the coils are grouped in 4 layers, and the layers are connected by elbow welding, the following disadvantages exist in the coils:

[0006] (1) The number of welded joints is large. The number of welded joints in each circle is equal to the number of sides of the polygon, and the number of welded joints in each layer is the product of the number of circles of the coiled pipe and the number of sides of the polygon. Taking the 6-sided coiled pipe of the existing product as an example, the number of circles in each layer is 5, and each group of coiled pipes has 4 layers. Therefore, the number of its welded joints (excluding the welded joints between elbows) is 6 * 5 * 4 = 120, which is time-consuming and laborious.

[0007] (2) The joints between the coiled pipes are sharp-angle welds, which are prone to sharp-angle stress, the welding quality is unreliable, and the risk of leakage is high.

[0008] (3) Maintenance is difficult. Since the 4 layers of this cooling coiled pipe are a group, and the layers are connected by welding. After welding is completed, if there is a failure (leakage) in the middle 2 layers, maintenance cannot be carried out.

[0009] (4) The connection between each group of coiled pipes and the shell is welded, with a large amount of welding work, inconvenient operation, and time-consuming and laborious.

[0010] For the circular cooling coiled pipe, this cooling coiled pipe is composed of multiple layers and multiple circles of steel pipes. Each layer of the cooling coiled pipe is composed of multiple concentric circles. The diameter of each circle of the cooling coiled pipe starts from the center and gradually increases outward. Each circle of the cooling coiled pipe is connected into a passage through elbows. The 4 layers of this coiled pipe are a group, and the layers are connected by elbow welding. Therefore, this coiled pipe has the following disadvantages:

[0011] (1) Compared with the polygon cooling coiled pipe, the number of welded joints of this cooling coiled pipe is relatively reduced, but there are still a small number of welded joints. Since these welded joints are manually welded, the quality of the welded joints is uneven.

[0012] (2) Maintenance is difficult. Since the 4 layers of this cooling coiled pipe are a group, and the layers are connected by welding. After welding is completed, if there is a failure (leakage) in the middle 2 layers, maintenance cannot be carried out.

[0013] (3) The connection between each group of coiled pipes and the shell is welded, with a large amount of welding work, inconvenient operation, and time-consuming and laborious.

[0014] (4) The coiled pipe is spot-welded and fixed on the orifice plate. The orifice plate spacing is set according to the theoretical spacing. However, there is a certain error between the actual coiled pipe during the bending process and the theoretical size, and it cannot be accurately positioned. As a result, the vacant positions need to be modified during the manufacturing process, which causes a large amount of modification work and generates some additional workload. Summary of the Invention

[0015] The present invention aims to provide a cooling coiled pipe, and the technical problems to be solved at least include how to reduce a large amount of welding work in the cooling coiled pipe and make the cooling coiled pipe convenient for maintenance.

[0016] To achieve the above object, the present invention provides a cooling coil, comprising a steel pipe and a fixing plate, wherein the steel pipe is fixed on the fixing plate by a clamp; the steel pipe is arranged in the shape of a mosquito coil, and is formed by one-time rolling from the inside to the outside, and the whole coil formed by rolling has no secondary welding joints.

[0017] Preferably, the steel pipe is pre-spliced by an automatic steel pipe laser welding machine to ensure the quality of the welding joints.

[0018] Preferably, after the splicing of the steel pipe is completed, it is formed into a shape by one-time rolling using a bending pipe manufacturing die.

[0019] Preferably, before the splicing of the steel pipe, first calculate the heat transfer area required for cooling crystallization according to the process requirements, then convert it into the total length of the coil according to the outer diameter specification of the coil, and then evenly distribute it to each layer of the coil. After calculating the length of each layer of the coil, use an automatic steel pipe laser welding machine for splicing.

[0020] Preferably, the steel pipe includes a first steel pipe and a second steel pipe, and the first steel pipe is fixed on the upper surface of the fixing plate; the second steel pipe is fixed on the lower surface of the fixing plate.

[0021] Preferably, a detachable flexible connection structure is used to connect the first steel pipe and the second steel pipe.

[0022] Preferably, the detachable flexible connection structure includes a connecting elbow and a quick joint.

[0023] Preferably, the quick joint includes a ferrule welded joint body, a connecting nut for ferrule pipe joint, and a taper seal welded pipe for ferrule pipe joint. The ferrule welded joint body is used to be welded together with the first steel pipe or the second steel pipe; the taper seal welded pipe for ferrule pipe joint is used to be welded together with the connecting elbow; the connecting nut for ferrule pipe joint is used to connect the ferrule welded joint body and the taper seal welded pipe for ferrule pipe joint together.

[0024] Preferably, the fixing plate is fixedly connected to the fixing member in the vertical continuous cooling crystallizer by bolts.

[0025] Preferably, the calculation formula for the heat transfer area required for cooling crystallization is:

[0026] A = Q / K * (t2 - t1);

[0027] In the formula:

[0028] A is the heat transfer area required for cooling crystallization, and the calculation unit is: ㎡;

[0029] Q is the heat transfer amount per unit time, and the calculation unit is: W;

[0030] K is the heat transfer coefficient, which represents the heat transferred per unit time through a unit area when the temperature difference between the hot and cold fluids is 1 °C; the calculation unit is: W / ㎡•°C;

[0031] t2 is the average temperature of the material, and the calculation unit is: °C;

[0032] t1 is the average temperature of the heat exchange medium, and the calculation unit is: °C.

[0033] Preferably, the calculation formula for the total length of the coiled pipe is:

[0034] L = A / (π * d);

[0035] In the formula:

[0036] L is the total length of the coiled pipe, and the calculation unit is: m;

[0037] A is the heat exchange area required for cooling crystallization, and the calculation unit is: ㎡;

[0038] d is the outer diameter of the coiled pipe, and the calculation unit is: m.

[0039] Preferably, the steel pipe includes a cooling fluid inlet provided at the center of the mosquito coil tray and a cooling fluid outlet provided at the periphery of the mosquito coil tray. The wall thickness of the steel pipe conforms to the heat transfer enhancement correction function, and the heat transfer enhancement correction function is: exp ,

[0040] In the formula:

[0041] x is the distance along the central axis between any point on the central axis of the steel pipe and the cooling fluid inlet, and the calculation unit is: m; 0 ≤ x ≤ L, where L is the total length of the coiled pipe;

[0042] σ is the curvature of the steel pipe corresponding to the position where the distance along the central axis from the cooling fluid inlet is x;

[0043] h0 is the wall thickness of the steel pipe at the cooling fluid inlet, and the calculation unit is: m.

[0044] This application also provides a manufacturing method for a cooling coiled pipe, including the following steps:

[0045] S1. Calculate the heat exchange area required for cooling crystallization according to the process requirements, then convert it into the total length of the coiled pipe according to the outer diameter specification of the coiled pipe, and then evenly distribute it to each layer of the coiled pipe to calculate the length of each layer of the coiled pipe;

[0046] S2. After calculating the length of each layer of the coiled pipe, splice the steel pipes in advance with a special steel pipe laser automatic welding machine to ensure the quality of the welded joints;

[0047] After the steel pipes are spliced, they are formed by one-time rolling using a pipe bending manufacturing die, and the entire coiled pipe formed by rolling has no secondary welding joints.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] The present invention is a type of tubular cooling coil. The cooling coiled pipe described in the present invention is mainly applied to vertical continuous cooling and crystallization equipment, and is mainly used in the production technologies of domestic sugar alcohols (such as glucose, sorbitol, mannitol, etc.), amino acid industries (such as sodium glutamate, citric acid, etc.), pharmaceutical industries, etc. using corn, rice or other raw materials. Its structure is a mosquito coil-shaped coiled pipe structure. The coiled pipe structure is arranged with pipes in the shape of a mosquito coil tray, and is formed by one-time rolling from the inside to the outside. The entire coiled pipe has no secondary welding joints, and the quality of the coiled pipe is reliable without any leakage risk.

[0050] In the cooling coiled pipe described in the present invention, the steel pipe and the fixing plate are fixed by a clamp, which is not affected by the manufacturing error of the coiled pipe and can be fixed anywhere according to the actual position of the coiled pipe. In this application, the cooling tray and the fixing part are fixedly connected by bolts, which are detachable and convenient for maintenance. Description of the Drawings

[0051] The drawings are used to provide a further understanding of the technical solution of the present invention, and constitute a part of the specification. Together with the specific implementation manners of this application, they are used to explain the technical solution of the present invention and do not constitute a limitation to the technical solution of the present invention.

[0052] Figure 1 It is a top view of the cooling coiled pipe described in the present invention.

[0053] Figure 2 It is a side view of the cooling coiled pipe described in the present invention.

[0054] Figure 3 It is a connection schematic diagram of different layers of cooling coiled pipes.

[0055] Figure 4 It is a connection schematic diagram between the fixing part and the fixing plate in a vertical continuous cooling crystallizer.

[0056] Figure 5 It is an overall structural schematic diagram of the described quick connector.

[0057] Figure 6 It is an exploded schematic diagram of the described quick connector. Specific Embodiments

[0058] The present invention is described in more detail below to facilitate the understanding of the present invention.

[0059] As Figure 1 and Figure 2As shown in the figure, the cooling coil of the present invention includes a steel pipe 1 and a fixing plate 4, and the steel pipe 1 is fixed on the fixing plate 4 through a clamp 5; the steel pipe 1 is arranged in the shape of a mosquito coil, and is rolled up at one time from the inside to the outside, and there is no secondary welding joint in the whole coiled pipe formed by rolling.

[0060] In the prior art, the steel pipe is fixed to the orifice plate by spot welding, which is not convenient to adjust. In this application, the clamp type fixing is adopted, which is not affected by the manufacturing error of the coiled pipe and can be fixed anywhere according to the actual position of the coiled pipe.

[0061] Preferably, the steel pipes are spliced in advance by an automatic steel pipe laser welding machine to ensure the quality of the welding joints.

[0062] Preferably, after the steel pipes are spliced, they are formed into a coil at one time by using a bending pipe manufacturing die.

[0063] Preferably, before the steel pipes are spliced, first calculate the heat transfer area required for cooling crystallization according to the process requirements, then convert it into the total length of the coiled pipe according to the outer diameter specification of the coiled pipe, and then evenly distribute it to each layer of the coiled pipe. After calculating the length of each layer of the coiled pipe, use an automatic steel pipe laser welding machine to splice it.

[0064] The calculation formula for the heat transfer area required for cooling crystallization is:

[0065] A = Q / K * (t2 - t1);

[0066] In the formula:

[0067] A is the heat transfer area required for cooling crystallization, and the calculation unit is: ㎡;

[0068] Q is the heat transfer amount per unit time, and the calculation unit is: W;

[0069] K is the heat transfer coefficient, which represents the heat transferred through a unit area per unit time when the temperature difference between the hot and cold fluids is 1℃; the calculation unit is: W / ㎡•℃;

[0070] t2 is the average temperature of the material, and the calculation unit is: ℃;

[0071] t1 is the average temperature of the heat transfer medium, and the calculation unit is: ℃.

[0072] The calculation formula for the total length of the coiled pipe is:

[0073] L = A / π * d;

[0074] In the formula:

[0075] L is the total length of the coiled pipe, and the calculation unit is: m;

[0076] A is the heat transfer area required for cooling crystallization, and the calculation unit is: ㎡;

[0077] d is the outer diameter of the coiled pipe, and the unit of calculation is: m.

[0078] In a preferred embodiment, the steel pipe 1 includes a cooling fluid inlet 2 provided at the center of the mosquito coil tray and a cooling fluid outlet 3 provided at the periphery of the mosquito coil tray. The wall thickness h of the steel pipe 1 conforms to a heat transfer enhancement correction function, and the heat transfer enhancement correction function is:

[0079] exp ,

[0080] In the formula:

[0081] x is the distance along the central axis between any point on the central axis of the steel pipe 1 and the cooling fluid inlet 2, and the unit of calculation is: m; 0 ≤ x ≤ L, where L is the total length of the coiled pipe;

[0082] h is the wall thickness of the steel pipe at point x, and the unit of calculation is: m;

[0083] σ is the curvature of the steel pipe corresponding to the distance x along the central axis from the cooling fluid inlet 2;

[0084] h0 is the wall thickness of the steel pipe 1 at the cooling fluid inlet 2, and the unit of calculation is: m.

[0085] Since the heat transfer condition of the cooling coiled pipe in the vertical continuous cooling crystallizer is relatively complex, the heat transfer efficiency is affected by multiple factors such as the change of the temperature of the cooling fluid along the length direction of the coiled pipe, the wall thickness of the steel pipe, and the crystallization state on the outer side of the steel pipe. In order to improve the heat transfer efficiency of the cooling coiled pipe as much as possible, the applicant fitted the above heat transfer enhancement correction function based on a large amount of test data. The actual use results show that the heat transfer efficiency of the cooling coiled pipe that conforms to the above heat transfer enhancement correction function has been effectively improved. Compared with the control example in which the entire steel pipe has the same wall thickness, the heat transfer efficiency of the cooling coiled pipe that conforms to the above heat transfer enhancement correction function has been increased by at least 27.3%.

[0086] For the processing of the steel pipe, by inputting the above heat transfer enhancement correction function into the numerical control machine tool and grinding inside the steel pipe before splicing with the steel pipe laser automatic welder, the required wall thickness can be obtained.

[0087] It should be noted that the units (m, i.e., meters) of the physical quantities (the distance x along the central axis between the heat exchange enhancement correction function and the cooling fluid inlet 2, the wall thickness h0 of the steel pipe 1 at the cooling fluid inlet 2, etc.) in the heat exchange enhancement correction function are only used to represent the magnitude of the numerical value and do not participate in the operations in the formula. This is because the heat exchange enhancement correction function is a fitting function obtained by fitting through SCILAB software and experimental data, rather than a physical formula or a mathematical formula obtained through strict mathematical derivation. For example, assuming h0 is 10 meters, if the unit is changed to centimeters, then h becomes 100 centimeters. The unit "meter" is only used to represent the magnitude of the numerical value "10" and does not participate in the operations in the function. If the unit "meter" is not restricted in the formula, it may cause those skilled in the art to use the numerical value "100 centimeters" to substitute into the formula for calculation, resulting in chaotic calculation results.

[0088] Preferably, the steel pipe 1 includes a first steel pipe 11 and a second steel pipe 12. The first steel pipe 11 is fixed on the upper surface of the fixing plate 4; the second steel pipe 12 is fixed on the lower surface of the fixing plate 4.

[0089] Preferably, a detachable and flexible connection structure is used to connect the first steel pipe 11 and the second steel pipe 12.

[0090] Preferably, the detachable and flexible connection structure includes a connecting elbow 13 and a quick connector 14.

[0091] Preferably, the fixing plate 4 and the fixing member 15 in the vertical continuous cooling crystallizer are fixedly connected by bolts 16.

[0092] In the prior art, the cooling plate and the fixing member are fixedly connected by welding, which is non-detachable and inconvenient for maintenance, and even impossible to maintain. In this application, bolted fixed connection is adopted, which is detachable and convenient for maintenance. [[ID=I6]]

[0093] As Figure 5 and Figure 6 shown, in a preferred embodiment, the quick connector 14 includes a ferrule welding joint body 141, a connecting nut 142 for ferrule pipe joints, and a taper seal welding pipe 143 for ferrule pipe joints. The ferrule welding joint body 141 is used to be welded to the first steel pipe 11 or the second steel pipe 12; the taper seal welding pipe 143 for ferrule pipe joints is used to be welded to the connecting elbow 13; the connecting nut 142 for ferrule pipe joints is used to connect the ferrule welding joint body 141 and the taper seal welding pipe 143 for ferrule pipe joints together.

[0094] Preferably, an O-ring seal is provided inside the taper seal welding pipe 143 for ferrule pipe joints.

[0095] The present application also provides a method for manufacturing a cooling coil, including the following steps:

[0096] S1. Calculate the heat exchange area required for cooling crystallization according to process requirements, then convert it into the total length of the coil based on the outer diameter specification of the coil, and then evenly distribute it to each layer of the coil to calculate the length of each layer of the coil.

[0097] S2. After calculating the length of each layer of the coil, splice the steel pipes in advance with a special automatic laser welding machine for steel pipes to ensure the quality of the welding joints.

[0098] S3. After the steel pipes are spliced, use a bending die to roll and form them in one go. The entire coil formed by rolling has no secondary welding joints. The quality of the coil is reliable and there is no risk of any leakage.

[0099] In the present application, the coil is fixed by a clamp type, which is not affected by the manufacturing error of the coil and can be fixed anywhere according to the actual position of the coil. If multiple layers of coils need to be combined, a detachable flexible connection is used between each layer of coils to ensure that there is no maintenance blind area for each layer of coils. In addition, the connection between each group of coils and the connecting components is of a detachable flexible connection type, which reduces a large amount of welding work, has no welding deformation, and is convenient for maintenance.

[0100] The preferred embodiments of the present invention have been described above, but they are not intended to limit the present invention. Those skilled in the art can make improvements and changes to the embodiments disclosed herein without departing from the scope and spirit of the present invention.

Claims

1. A manufacturing method of a cooling coil, characterized in that, It includes the following steps: S1. Calculate the heat transfer area required for cooling crystallization according to the process requirements, then convert it into the total length of the coiled pipe according to the outer diameter specification of the coiled pipe, and then evenly distribute it to each layer of the coiled pipe to calculate the length of each layer of the coiled pipe; S2. After calculating the length of each layer of the coiled pipe, splice the steel pipes in advance with a special steel pipe laser automatic welding machine to ensure the quality of the welded joints; S3. After the steel pipe splicing is completed, use a bend pipe manufacturing die to roll it into shape at one time, and there is no secondary welded joint in the entire coiled pipe formed by rolling; The cooling coiled pipe includes a steel pipe and a fixing plate, and the steel pipe is fixed on the fixing plate by a clamp; the steel pipe is arranged in the shape of a mosquito coil, and is rolled into shape at one time from the inside to the outside, and there is no secondary welded joint in the entire coiled pipe formed by rolling; The fixing plate is fixedly connected to the fixing part in the vertical continuous cooling crystallizer by bolts; The calculation formula for the heat transfer area required for cooling crystallization is: A = Q / K*(t2 - t1); In the formula: A is the heat transfer area required for cooling crystallization, and the calculation unit is: ㎡; Q is the heat transfer amount per unit time, and the calculation unit is: W; K is the heat transfer coefficient, which represents the heat transferred per unit area per unit time when the temperature difference between the hot and cold fluids is 1℃; the calculation unit is: W / ㎡·℃; t2 is the average temperature of the material, and the calculation unit is: ℃; t1 is the average temperature of the heat transfer medium, and the calculation unit is: ℃; The steel pipe includes a cooling fluid inlet arranged at the center of the mosquito coil and a cooling fluid outlet arranged at the periphery of the mosquito coil. The wall thickness of the steel pipe conforms to the heat transfer enhancement correction function, and the heat transfer enhancement correction function is: In the formula: x is the distance along the central axis between any point on the central axis of the steel pipe and the cooling fluid inlet, and the calculation unit is: m; 0 ≤ x ≤ L, where L is the total length of the coiled pipe; σ is the curvature of the steel pipe corresponding to the position where the distance along the central axis from the cooling fluid inlet is x; h0 is the wall thickness of the steel pipe at the cooling fluid inlet, and the calculation unit is: m.

2. The manufacturing method of the cooling coil according to claim 1, characterized in that, The steel pipe is spliced in advance with a steel pipe laser automatic welding machine to ensure the quality of the welded joints.

3. The manufacturing method of the cooling coil according to claim 2, characterized in that, After the steel pipe splicing is completed, use a bend pipe manufacturing die to roll it into shape at one time.

4. The manufacturing method of the cooling coil according to claim 2, characterized in that, Before splicing the steel pipe, first calculate the heat transfer area required for cooling crystallization according to the process requirements, then convert it into the total length of the coiled pipe according to the outer diameter specification of the coiled pipe, and then evenly distribute it to each layer of the coiled pipe. After calculating the length of each layer of the coiled pipe, then splice it with a steel pipe laser automatic welding machine.

5. The manufacturing method of the cooling coil according to claim 1, wherein, The steel pipe includes a first steel pipe and a second steel pipe. The first steel pipe is fixed on the upper surface of the fixing plate; the second steel pipe is fixed on the lower surface of the fixing plate.

6. The manufacturing method of the cooling coil according to claim 5, wherein, The first steel pipe and the second steel pipe are connected in a detachable and flexible connection structure.

7. The manufacturing method of the cooling coil according to claim 6, characterized in that The detachable and flexible connection structure includes a connecting elbow and a quick joint.

8. The manufacturing method of the cooling coil according to claim 7, characterized in that, The quick connector described above includes a ferrule welded joint body, a connection nut for a ferrule pipe joint, and a taper seal welded pipe for a ferrule pipe joint. The ferrule welded joint body is used to be welded to the first steel pipe or the second steel pipe; the taper seal welded pipe for a ferrule pipe joint is used to be welded to the connecting elbow; the connection nut for a ferrule pipe joint is used to connect the ferrule welded joint body and the taper seal welded pipe for a ferrule pipe joint together.

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