Cooling coil

Abstract

The 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 hoop; the steel pipe is arranged according to the shape of the mosquito-repellent incense disc and is formed by rolling from inside to outside at a time, and the whole coiled pipe formed by rolling is not provided with a secondary welding joint. The cooling coil pipe is mainly applied to vertical continuous cooling crystallization equipment and is of a mosquito-repellent incense-shaped coil pipe structure. The coil pipe structure is arranged according to the shape of a mosquito coil and is formed by one-time rolling from inside to outside, the whole coil pipe is not provided with a secondary welding joint, the quality of the coil pipe is reliable, and no leakage risk exists.

Description

Technical Field

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

[0002] In the production technologies of sugar alcohols (such as glucose, sorbitol, mannitol, etc.) made of corn, rice or other raw materials, amino acid industry (such as sodium glutamate, citric acid, etc.), pharmaceutical industry, etc., medium and small horizontal cooling crystallizers are currently mostly used. Due to the technical structure, the cooling and heat exchange is insufficient, the material is easy to leak, and its operation mode is intermittent operation, which cannot achieve continuous crystallization. The vertical continuous cooling crystallizer is a vertical cylindrical container. A plurality of cooling plates are arranged in sequence from bottom to top in the shell. The cooling plates are respectively connected to the cooling medium pipeline outside the shell, which can achieve continuous crystallization, improve production efficiency, and maintain stable product quality; its reasonable cooling crystallization structure makes it easy to control and adjust the crystallization process parameters, and can realize multi-level temperature gradient control. The equipment can be equipped with a computer system to realize automatic control and save consumption. In the prior art, the cooling plates of the vertical continuous cooling crystallizer are divided into tubular cooling plates and disc cooling plates. The existing tubular cooling plates are divided into two forms: polygonal coils and annular cooling plates: 1. Polygonal coil, which is formed into a polygonal shape by winding multiple 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 a certain order in the tube, and the material flows from top to bottom outside the tube, and is stirred to form heat exchange.

[0003] 2. Ring-shaped cooling coil, which is composed of multiple layers and multiple circles of steel pipes. Each layer of cooling coil is composed of multiple concentric rings. The diameter of each circle of cooling coil starts from the center and gradually increases outward. Each circle of cooling coils is connected to form a passage through an elbow. The cooling module divides the cooling coil into layers and blocks according to the needs of the cooling process to form a cooling module. The layers are connected to form a passage with corresponding pipe fittings as needed. The lower end of the tube is connected to the cooling medium inlet, and the upper end is connected to the cooling medium outlet. The cooling medium flows in a certain order in the tube, and the material flows from top to bottom outside the tube, and is stirred to form a heat exchange.

[0004] For the polygonal cooling coil, since the coil is welded into a polygonal shape by straight pipes or elbows, and the coil is a group of 4 layers, and the layers are connected by elbow welding, the coil has the following disadvantages: (1) There are many welding joints. The number of welding joints in each circle is the number of sides of the polygon, and the number of welding joints in each layer is the product of the number of circles of the coil and the number of sides of the polygon. Taking the hexagonal coil currently in service as an example, the number of circles in each layer is 5, and each group of coils is 4 layers. Therefore, the number of welding joints (excluding welding joints between elbows) is 6*5*4=120, which is labor-intensive and time-consuming.

[0005] (2) The joints between coils are sharp-angle welded, which easily generates sharp-angle stress, unreliable welding quality, and a high risk of leakage.

[0006] (3) Difficulty in maintenance. Since the cooling coil is composed of four layers, each layer is connected by welding. After welding, if there is a fault (leakage) in the middle two layers, it will be impossible to repair.

[0007] (4) Each set of coils is connected to the shell by welding, which is labor-intensive, inconvenient, and time-consuming.

[0008] For the annular cooling coil, the cooling coil is composed of multiple layers and multiple circles of steel pipes. Each layer of cooling coil is composed of multiple concentric rings. The diameter of each circle of cooling coil starts from the center and gradually increases outward. Each circle of cooling coils is connected to form a passage through an elbow. The coil is a group of 4 layers, and the layers are connected by elbow welding. Therefore, the coil has the following disadvantages: (1) Compared with the polygonal cooling coil, the number of welded joints of this cooling coil is relatively reduced, but there are still a small number of welded joints. Since the welded joints are manually welded, the quality of the welded joints varies.

[0009] (2) Difficulty in maintenance. Since the cooling coil is composed of four layers, each layer is connected by welding. After welding, if there is a fault (leakage) in the middle two layers, it will be impossible to repair.

[0010] (3) Each set of coils is connected to the shell by welding, which is labor-intensive, inconvenient, and time-consuming.

[0011] (4) The coil is spot welded on the orifice plate, and the orifice plate spacing is set according to the theoretical spacing. However, there is a certain error between the actual coil and the theoretical size during the bending process, and it cannot be accurately positioned, which leads to the need to modify the vacancy during the manufacturing process, resulting in a large amount of modification work and some additional workload. Summary of the invention

[0012] The present invention aims to provide a cooling coil, and the technical problem to be solved at least includes how to reduce a large amount of welding work in the cooling coil and make the cooling coil easy to maintain.

[0013] In order to achieve the above-mentioned purpose, the present invention provides a cooling coil, including 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 rolled from the inside out at one time, and the entire rolled coil has no secondary welding joints.

[0014] Preferably, the steel pipes are spliced ​​in advance using a steel pipe automatic laser welder to ensure the quality of the welded joints.

[0015] Preferably, after the steel pipes are spliced, they are rolled into shape in one go using a pipe bending mold.

[0016] Preferably, before splicing the steel pipes, the heat exchange area required for cooling crystallization is first calculated according to the process requirements, then converted into the total length of the coil according to the outer diameter specification of the coil, and then evenly divided into each layer of coils. After the length of each layer of coils is calculated, they are spliced ​​using a steel pipe automatic laser welding machine.

[0017] Preferably, 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.

[0018] Preferably, the first steel pipe and the second steel pipe are connected by a detachable live connection structure.

[0019] Preferably, the detachable movable connection structure includes a connecting elbow and a quick connector.

[0020] Preferably, the quick connector includes a ferrule-type welding joint body, a connecting nut for a ferrule-type pipe joint and a cone-sealed welding pipe for a ferrule-type pipe joint, the ferrule-type welding joint body is used to be welded together with the first steel pipe or the second steel pipe; the cone-sealed welding pipe for a ferrule-type pipe joint is used to be welded together with a connecting elbow; the connecting nut for a ferrule-type pipe joint is used to connect the ferrule-type welding joint body and the cone-sealed welding pipe for a ferrule-type pipe joint together.

[0021] Preferably, the fixing plate is fixedly connected to the fixing parts in the vertical continuous cooling crystallizer by bolts.

[0022] Preferably, the calculation formula for the heat exchange area required for cooling crystallization is: A=Q / K*(t2-t1); Where: A is the heat exchange area required for cooling crystallization, calculated in square meters; Q is the heat transfer per unit time, calculated in W; K is the heat transfer coefficient, which indicates the amount of heat transferred through a unit area in a unit time when the temperature difference between the cold and hot fluids is 1°C; the calculation unit is: W / ㎡•℃; t2 is the average temperature of the material, calculated in ℃; t1 is the average temperature of the heat exchange medium, calculated in units of ℃.

[0023] Preferably, the total length of the coil is calculated as follows: L = A / π*d; Where: L is the total length of the coil, calculated in m; A is the heat exchange area required for cooling crystallization, calculated in square meters; d is the outer diameter of the coil, calculated in m.

[0024] Preferably, the steel pipe comprises 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, and the wall thickness of the steel pipe conforms to the heat exchange enhancement correction function, and the heat exchange enhancement correction function is: exp , Where: x is the distance between any point on the central axis of the steel pipe and the cooling fluid inlet along the central axis, and the calculation unit is: m; 0≤x≤L, L is the total length of the coil; σ is the curvature of the steel pipe corresponding to the distance x along the central axis from the cooling fluid inlet; h0 is the wall thickness of the steel pipe at the inlet of the cooling fluid, calculated in m.

[0025] The present application also provides a method for manufacturing a cooling coil, comprising the following steps: S1. Calculate the heat exchange 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 of the coil, and then divide it equally into each layer of coils, and calculate the length of each layer of coils; S2. After calculating the length of each layer of coil, the steel pipes are spliced ​​in advance using a dedicated steel pipe laser automatic welding machine to ensure the quality of the welded joints; S3. After the steel pipes are spliced, they are rolled into shape in one go using a pipe bending mold. The entire coil has no secondary welding joints.

[0026] Compared with the prior art, the present invention has the following beneficial effects: The present invention is a kind of tubular cooling plate. The cooling coil described in the present invention is mainly used in vertical continuous cooling crystallization equipment, and is mainly used in domestic production technologies such as sugar alcohol (such as glucose, sorbitol, mannitol, etc.) with corn, rice or other raw materials, amino acid industry (such as sodium glutamate, citric acid, etc.), and pharmaceutical industry. Its structure is a mosquito coil structure. The coil structure is arranged in the shape of a mosquito coil, and is rolled from the inside to the outside in one go. The entire coil has no secondary welding joints, and the coil quality is reliable without any leakage risk.

[0027] The steel pipe and the fixing plate in the cooling coil of the present invention are fixed by a clamp, which is not affected by the manufacturing error of the coil and can be fixed anywhere according to the actual position of the coil. In the present application, the cooling plate and the fixing member are fixed by bolts, which are detachable and convenient for maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying 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 methods of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0029] Figure 1 1 is a top view of the cooling coil described in the present invention.

[0030] Figure 2 1 is a side view of the cooling coil according to the present invention.

[0031] Figure 3 It is a schematic diagram of the connection of cooling coils at different layers.

[0032] Figure 4 It is a schematic diagram of the connection between the fixing parts and the fixing plate in the vertical continuous cooling crystallizer.

[0033] Figure 5 It is a schematic diagram of the overall structure of the quick connector.

[0034] Figure 6 It is an exploded schematic diagram of the quick connector. DETAILED DESCRIPTION

[0035] The present invention is described in more detail hereinafter to facilitate understanding of the present invention.

[0036] like Figure 1 and Figure 2 As shown, the cooling coil of the present invention comprises a steel pipe 1 and a fixing plate 4, wherein the steel pipe 1 is fixed to the fixing plate 4 by a clamp 5; the steel pipe 1 is arranged in the shape of a mosquito coil and is rolled from the inside out at one time, and the entire rolled coil has no secondary welding joints.

[0037] In the prior art, the steel pipe is fixed on the orifice plate by spot welding, which is inconvenient to adjust. The present application adopts a clamp-type fixation, which is not affected by the manufacturing error of the coil and can be fixed anywhere according to the actual position of the coil.

[0038] Preferably, the steel pipes are spliced ​​in advance using a steel pipe automatic laser welder to ensure the quality of the welded joints.

[0039] Preferably, after the steel pipes are spliced, they are rolled into shape in one go using a pipe bending mold.

[0040] Preferably, before splicing the steel pipes, the heat exchange area required for cooling crystallization is first calculated according to the process requirements, then converted into the total length of the coil according to the outer diameter specification of the coil, and then evenly divided into each layer of coils. After the length of each layer of coils is calculated, they are spliced ​​using a steel pipe automatic laser welding machine.

[0041] The calculation formula for the heat exchange area required for cooling crystallization is: A=Q / K*(t2-t1); Where: A is the heat exchange area required for cooling crystallization, calculated in square meters; Q is the heat transfer per unit time, calculated in W; K is the heat transfer coefficient, which indicates the amount of heat transferred through a unit area in a unit time when the temperature difference between the cold and hot fluids is 1°C; the calculation unit is: W / ㎡•℃; t2 is the average temperature of the material, calculated in ℃; t1 is the average temperature of the heat exchange medium, calculated in units of ℃.

[0042] The total length of the coil is calculated as: L = A / π*d; Where: L is the total length of the coil, calculated in m; A is the heat exchange area required for cooling crystallization, calculated in square meters; d is the outer diameter of the coil, calculated in m.

[0043] In a preferred embodiment, the steel pipe 1 includes a cooling fluid inlet 2 arranged at the center of the mosquito coil and a cooling fluid outlet 3 arranged at the periphery of the mosquito coil. The wall thickness h of the steel pipe 1 conforms to the heat exchange enhancement correction function, and the heat exchange enhancement correction function is: exp , Where: x is the distance between any point on the central axis of the steel pipe 1 and the cooling fluid inlet 2 along the central axis, and the calculation unit is: m; 0≤x≤L, L is the total length of the coil; h is the wall thickness of the steel pipe at point x, calculated in m; σ is the curvature of the steel pipe corresponding to the distance x along the central axis from the cooling fluid inlet 2; h0 is the wall thickness of the steel pipe 1 at the cooling fluid inlet 2, and the calculation unit is: m.

[0044] Since the heat exchange conditions of the cooling coil in the vertical continuous cooling crystallizer are relatively complex, the heat exchange efficiency is affected by multiple factors such as the change in the temperature of the cooling fluid along the length of the coil, the wall thickness of the steel pipe, the crystallization state of the outer side of the steel pipe, etc. In order to maximize the heat exchange efficiency of the cooling coil, the applicant fitted the above heat exchange enhancement correction function based on a large amount of test data. The actual use results show that the heat exchange efficiency of the cooling coil that meets the above heat exchange enhancement correction function has been effectively improved. Compared with the control example in which the entire steel pipe uses the same wall thickness, the heat exchange efficiency of the cooling coil that meets the above heat exchange enhancement correction function has been increased by at least 27.3%.

[0045] For the processing of steel pipes, by inputting the above heat transfer enhancement correction function into a CNC machine tool, the required wall thickness can be obtained by grinding inside the steel pipe before splicing it using a steel pipe automatic laser welding machine.

[0046] It should be pointed out that the units (m, i.e., meters) of the physical quantities in the heat exchange enhancement correction function (the distance x along the central axis from the cooling fluid inlet 2, the wall thickness h0 of the steel pipe 1 at the cooling fluid inlet 2, etc.) are only used to indicate the magnitude of the values ​​and do not participate in the calculations in the formula. This is because the heat exchange enhancement correction function is a fitting function obtained by fitting the SCILAB software and experimental data, rather than a physical formula or mathematical formula obtained through strict mathematical derivation. For example, assuming that h0 is 10 meters, if the unit is changed to centimeters, h becomes 100 centimeters, and the unit of "meter" is only used to indicate the magnitude of the value "10" and does not participate in the calculations in the function. If the unit of "meter" is not limited to the formula, it may cause those skilled in the art to use the value of "100 centimeters" into the formula calculation, resulting in confusing calculation results.

[0047] 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 .

[0048] Preferably, the first steel pipe 11 and the second steel pipe 12 are connected by a detachable live connection structure.

[0049] Preferably, the detachable movable connection structure includes a connecting elbow 13 and a quick connector 14 .

[0050] Preferably, the fixing plate 4 is fixedly connected to the fixing member 15 in the vertical continuous cooling crystallizer by bolts 16 .

[0051] In the prior art, the cooling plate and the fixing member are fixed by welding, which is not removable, inconvenient to repair, or even impossible to repair. The present application adopts bolt fixing connection, which is removable and convenient to repair.

[0052] like Figure 5 and Figure 6 As shown, in a preferred embodiment, the quick connector 14 includes a ferrule-type welding joint body 141, a connecting nut 142 for a ferrule-type pipe joint and a cone-sealed welding pipe 143 for a ferrule-type pipe joint, the ferrule-type welding joint body 141 is used to be welded together with the first steel pipe 11 or the second steel pipe 12; the cone-sealed welding pipe 143 for a ferrule-type pipe joint is used to be welded together with the connecting elbow 13; the connecting nut 142 for a ferrule-type pipe joint is used to connect the ferrule-type welding joint body 141 and the cone-sealed welding pipe 143 for a ferrule-type pipe joint together.

[0053] Preferably, an O-ring is provided inside the cone sealing welding pipe 143 of the ferrule type pipe joint.

[0054] The present application also provides a method for manufacturing a cooling coil, comprising the following steps: S1. Calculate the heat exchange 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 of the coil, and then divide it equally into each layer of coils, and calculate the length of each layer of coils; S2. After calculating the length of each layer of coil, the steel pipes are spliced ​​in advance using a dedicated steel pipe laser automatic welding machine to ensure the quality of the welded joints; S3. After the steel pipes are spliced, they are rolled into shape in one go using a pipe bending mold. The entire coil has no secondary welding joints. The coil quality is reliable and there is no risk of leakage.

[0055] The coils in this application are fixed by clamps, which are not affected by the manufacturing errors of the coils and can be fixed anywhere according to the actual position of the coils. If a multi-layer coil combination is required, a detachable live connection is used between each layer of coils to ensure that there is no blind spot for maintenance of each layer of coils. In addition, the fixation between each group of coils and the connecting parts adopts a detachable live connection type, which reduces a lot of welding work, has no welding deformation, and is convenient for maintenance.

[0056] The above describes the preferred embodiments of the present invention, but it is not intended to limit the present invention. Those skilled in the art may make improvements and changes to the embodiments disclosed herein without departing from the scope and spirit of the present invention.

Claims

1. A cooling coil, characterized in that: The cooling coil comprises 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 rolled from the inside out at one time, and the entire rolled coil has no secondary welding joints.

2. The cooling coil according to claim 1, characterized in that: The steel pipes are spliced ​​in advance using a steel pipe laser automatic welding machine to ensure the quality of the welded joints.

3. The cooling coil according to claim 2, characterized in that: After the steel pipes are spliced, they are rolled into shape in one go using a pipe bending mold.

4. The cooling coil according to claim 2, characterized in that: Before splicing the steel pipes, the heat exchange area required for cooling and crystallization is first calculated according to the process requirements, then converted into the total length of the coil according to the outer diameter specification of the coil, and then evenly divided into each layer of coils. After calculating the length of each layer of coils, they are spliced ​​using a steel pipe automatic laser welding machine.

5. The cooling coil according to claim 1, characterized in that: The steel pipe comprises a first steel pipe and a second steel pipe, wherein the first steel pipe is fixed on the upper surface of the fixing plate; and the second steel pipe is fixed on the lower surface of the fixing plate.

6. The cooling coil according to claim 5, characterized in that: The first steel pipe and the second steel pipe are connected by a detachable movable connection structure.

7. The cooling coil according to claim 6, characterized in that: The detachable live connection structure comprises a connecting elbow and a quick connector.

8. The cooling coil according to claim 7, characterized in that: The quick connector includes a ferrule-type welding joint body, a connecting nut for a ferrule-type pipe joint and a cone-sealed welding pipe for a ferrule-type pipe joint. The ferrule-type welding joint body is used to be welded together with a first steel pipe or a second steel pipe; the cone-sealed welding pipe for a ferrule-type pipe joint is used to be welded together with a connecting elbow; the connecting nut for a ferrule-type pipe joint is used to connect the ferrule-type welding joint body and the cone-sealed welding pipe for a ferrule-type pipe joint together.

9. The cooling coil according to claim 1, characterized in that: The fixing plate is fixedly connected to the fixing parts in the vertical continuous cooling crystallizer by bolts.

10. The cooling coil according to claim 1, characterized in that: The calculation formula for the heat exchange area required for the cooling crystallization is: A=Q / K*(t2-t1); Where: A is the heat exchange area required for cooling crystallization, calculated in square meters; Q is the heat transfer per unit time, calculated in W; K is the heat transfer coefficient, which indicates the amount of heat transferred through a unit area in a unit time when the temperature difference between the cold and hot fluids is 1°C; the calculation unit is: W / ㎡•℃; t2 is the average temperature of the material, calculated in ℃; t1 is the average temperature of the heat exchange medium, calculated in units of ℃.

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