Three-pipe combined double-pipe heat exchanger and control method thereof

Abstract

The application provides a three-pipeline combined double-pipe heat exchanger and a control method thereof. The double-pipe heat exchanger comprises an outer pipe, an inner pipe, a liquid inlet pipe, a multi-way reversing valve, a first temperature sensor, a second temperature sensor and a controller. The number of the inner pipes is several, and the inner pipes are connected in parallel in the outer pipe. The liquid inlet pipe is connected to the inlets of the inner pipes through the multi-way reversing valve. The outer pipe is used for passing a first fluid, and the liquid inlet pipe is used for passing a second fluid. The first temperature sensor is arranged at the inlet of the outer pipe and used for monitoring the temperature of the first fluid. The second temperature sensor is arranged at the outlet of the liquid inlet pipe and used for monitoring the temperature of the second fluid. The controller is electrically connected with the multi-way reversing valve, the first temperature sensor and the second temperature sensor. According to the refrigeration / heating capacity requirement of the unit, the number of the inner pipes participating in heat exchange can be adjusted in real time, so that the upper limit of the unit capacity can be improved, and energy can be effectively saved.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger technology, specifically to a three-pipe combination shell-and-tube heat exchanger and its control method. Background Technology

[0002] In the field of shell-and-tube heat exchangers, the required cooling / heating capacity varies with the seasons. When demand is high, modifications to the pipe substrate structure are often used to achieve this, but the effect is not significant; and when capacity demand is low, it leads to energy waste. This problem is prevalent in shell-and-tube heat exchangers, causing considerable inconvenience to users and greatly limiting the application of the product.

[0003] In addition, the working pipeline is at risk of corrosion penetration, and the existing shell-and-tube heat exchangers lack corresponding pipeline protection mechanisms, resulting in poor overall safety of unit operation. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention provides a three-pipe combination shell-and-tube heat exchanger and its control method, which can improve the adaptability of the shell-and-tube heat exchanger to various operating conditions.

[0005] To achieve the above objectives, according to one aspect of the present invention, a three-pipe combination shell-and-tube heat exchanger is provided, comprising an outer tube, an inner tube, an inlet pipe, a multi-way reversing valve, a first temperature sensor, a second temperature sensor, and a controller;

[0006] The number of inner tubes is several, which are arranged in parallel inside the outer tube. The liquid inlet pipe is connected to the inlet of several inner tubes through the multi-way reversing valve. The outer tube is used to introduce a first fluid, and the liquid inlet pipe is used to introduce a second fluid.

[0007] The first temperature sensor is located at the inlet of the outer tube to monitor the temperature of the first fluid, and the second temperature sensor is located at the outlet of the inlet tube to monitor the temperature of the second fluid. The controller is electrically connected to the multi-way reversing valve, the first temperature sensor, and the second temperature sensor.

[0008] As an improvement of the present invention, the first fluid is a refrigerant and the second fluid is cooling water.

[0009] As an improvement of the present invention, the inner tube is a copper tube, and the inner tube is equipped with an ion monitor for monitoring the concentration of copper ions in the water, and the ion monitor is electrically connected to the controller.

[0010] As an improvement of the present invention, the flow direction of the first fluid is opposite to that of the second fluid.

[0011] As an improvement of the present invention, the inner tube is a spiral tube.

[0012] As an improvement of the present invention, the inner tube includes a first inner tube, a second inner tube and a third inner tube, and the multi-way reversing valve is a four-way reversing valve.

[0013] According to another aspect of the present invention, a control method for the above-described three-pipe combination shell-and-tube heat exchanger is provided, comprising the following steps:

[0014] The refrigerant and cooling water are pre-set to have two temperature differences: T1 and T2, where T1 < T2;

[0015] Obtain the real-time temperature difference T between the refrigerant and the cooling water;

[0016] When T≤T1, the three-inner-tube mode is adopted, and the first inner tube, the second inner tube and the third inner tube are all connected to the inlet tube;

[0017] When T1 < T ≤ T2, a two-inner-tube mode is adopted, and any two of the first inner tube, the second inner tube, and the third inner tube are connected to the inlet tube.

[0018] When T > T2, a single inner tube mode is adopted, and any one of the first inner tube, the second inner tube, and the third inner tube is connected to the inlet tube.

[0019] As an improvement of the present invention, the copper ion concentration in the cooling water is preset to c0;

[0020] When the inner tube is connected to the inlet pipe, the real-time concentration c of copper ions in the cooling water is obtained. If c > c0, the connection between the inner tube and the inlet pipe is disconnected.

[0021] By applying the technical solution of this invention, by setting several parallel inner tubes inside the outer tube and combining them with a multi-way reversing valve, the number of inner tubes participating in heat exchange can be adjusted in real time according to the temperature difference between the first fluid and the second fluid, thereby realizing the coordinated operation of multiple pipelines. This not only improves the upper limit of the unit's capacity but also effectively saves energy. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0023] Figure 1 This is a schematic diagram of the flow path of a shell-and-tube heat exchanger according to an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of a shell-and-tube heat exchanger according to an embodiment of the present invention;

[0025] Figure 3 This is a flowchart of the control method according to an embodiment of the present invention;

[0026] in,

[0027] 1-Outer tube; 2-Inner tube; 3-Inlet tube; 4-Multi-way reversing valve; 5-First temperature sensor; 6-Second temperature sensor; 7-Ion monitor; 21-First inner tube; 21-Second inner tube; 22-Third inner tube. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

[0029] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] like Figure 1 and Figure 2 As shown, this embodiment of the invention provides a three-pipe combination shell-and-tube heat exchanger, including an outer tube 1, an inner tube 2, an inlet pipe 3, a multi-way reversing valve 4, a first temperature sensor 5, a second temperature sensor 6, and a controller.

[0032] The inner tubes 2 are arranged in parallel inside the outer tube 1. The liquid inlet pipe 3 is connected to the inlet of the inner tubes 2 through a multi-way reversing valve 4. The outer tube 1 is used to introduce the first fluid, and the liquid inlet pipe 3 is used to introduce the second fluid. The first fluid and the second fluid can generate heat exchange.

[0033] The first temperature sensor 5 is installed at the inlet of the outer pipe 1 to monitor the temperature of the first fluid, and the second temperature sensor 6 is installed at the outlet of the inlet pipe 3 to monitor the temperature of the second fluid.

[0034] The multi-way reversing valve 4, the first temperature sensor 5, and the second temperature sensor 6 are all electrically connected to the controller. The controller can be set up independently or it can be integrated into the control system of the unit where the shell-and-tube heat exchanger is located.

[0035] By applying the technical solution of this invention, by setting several parallel inner tubes 2 inside the outer tube 1 and combining them with a multi-way reversing valve 4, the number of inner tubes 2 participating in heat exchange can be adjusted in real time according to the temperature difference between the first fluid and the second fluid, so as to realize the coordinated operation of multiple pipelines. When the cooling / heating capacity demand is high, multiple inner tubes exchange heat together. When the cooling / heating capacity demand is not high, the number of inner tubes participating in heat exchange is reduced, which not only increases the upper limit of the unit's capacity, but also effectively saves energy.

[0036] It should be noted that "several" in this application refers to two or more items, including two.

[0037] In this embodiment, the inner tube 2 is made of copper, the first fluid flowing into the outer tube 1 is refrigerant, and the second fluid flowing into the inner tube 2 is cooling water.

[0038] To improve the safety of the shell-and-tube heat exchanger in this embodiment, an ion monitor 7 is installed in each inner tube 2 to monitor the concentration of copper ions in the water and is electrically connected to the controller to monitor the cooling water of the inner tube 2. When the inner tube 2 is at risk of corrosion penetration, the copper ion concentration in the cooling water will change significantly. When it exceeds the monitoring threshold, it indicates a risk of leakage. The system can be shut down in time and switched to the backup pipeline, which can effectively protect the overall safety of the unit operation.

[0039] In this embodiment, there are three inner tubes 2, namely the first inner tube 21, the second inner tube 22 and the third inner tube 23. Correspondingly, the multi-way reversing valve 4 is a four-way reversing valve, and the four ports A, B, C and D are connected to the inlet pipe 3, the first inner tube 21, the second inner tube 22 and the third inner tube 23 respectively.

[0040] It should be noted that the multi-way reversing valve 4 can also be replaced by three electrically controlled valves, with each inner tube 2 controlled by an electrically controlled valve.

[0041] In this embodiment, to improve the heat exchange effect, the inner tube 2 is a spiral tube, and the flow direction of the refrigerant in the outer tube 1 is opposite to the flow direction of the cooling water in the inner tube 2.

[0042] According to an embodiment of the present invention, a control method corresponding to the above-described shell-and-tube heat exchanger is also provided, which is described below in conjunction with... Figure 3 The specific control process will be explained.

[0043] 1. Set two temperature differences between the refrigerant and the cooling water: T1 and T2, where T1 < T2, and set the copper ion concentration in the cooling water to c0;

[0044] 2. Power on;

[0045] 3. Obtain the real-time temperature difference T between the refrigerant and the cooling water;

[0046] 4. When T≤T1, it indicates that the temperature difference between the refrigerant and the cooling water is small. To ensure the heat exchange effect, a three-inner-pipe mode is adopted. At this time, AB, AC and AD of the four-way reversing valve are all connected. The system exchanges heat through the first inner pipe 21, the second inner pipe 22 and the third inner pipe 23 at the same time. Meanwhile, the ion monitors 7 in the first inner pipe 21, the second inner pipe 22 and the third inner pipe 23 are all turned on to monitor the copper ion concentration in real time.

[0047] 5. When T1 < T ≤ T2, it indicates that the temperature difference between the refrigerant and the cooling water is moderate. The heat exchange effect can be guaranteed by adopting the dual inner tube mode. At this time, any two of the four-way reversing valves AB, AC, and AD can be turned on. For example, when AB and AC are turned on, the system exchanges heat through the first inner tube 21 and the second inner tube 22. At the same time, the ion monitor 7 in the first inner tube 21 and the second inner tube 22 is turned on to monitor the copper ion concentration in real time.

[0048] 6. When T > T2, it indicates that the temperature difference between the refrigerant and the cooling water is large. The heat exchange effect can be guaranteed by using a single inner tube mode. At this time, any one of the four-way reversing valves AB, AC, and AD can be turned on. For example, when AB is turned on, the system exchanges heat through the first inner tube 21. At the same time, the ion monitor 7 in the first inner tube 21 is turned on to monitor the copper ion concentration in real time.

[0049] 7. Obtain the real-time concentration c of copper ions in the cooling water. If c≤c0, it indicates that there is no risk of leakage in the pipeline. After running for a specific time, enter the shutdown confirmation process.

[0050] 8. If c > c0, it indicates that there is a risk of leakage in the pipeline. In the three-inner-pipe mode, disconnect the inner pipe with the risk of leakage. In the two-inner-pipe mode or the single-inner-pipe mode, disconnect the inner pipe with the risk of leakage and switch to other inner pipes for replacement. The system reminds the user to replace the shell-and-tube heat exchanger. After running for a specific time, the system enters the shutdown confirmation process.

[0051] 9. After entering the shutdown process, the system asks whether to shut down. If the user confirms the shutdown, the system shuts down; if the user does not shut down, the system returns to process 3.

[0052] From the above description, it can be seen that the shell-and-tube heat exchanger of this application has at least the following advantages:

[0053] 1. Adjust the number of pipes participating in heat exchange to effectively save energy under different cooling / heating capacity requirements.

[0054] 2. The unit's capacity limit has been increased, and multiple pipelines work together to effectively improve the unit's heat exchange capacity.

[0055] 3. It has a corrosion penetration protection mechanism, which effectively protects the safe and reliable operation of the unit.

[0056] In the description of this invention, it should be understood that the orientations or positional relationships indicated by terms such as "center," "front," "back," "up," "down," "left," "right," "horizontal," "vertical," "horizontal," and "top," "bottom," etc., are generally based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0057] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0058] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A three-pipe combination shell-and-tube heat exchanger, characterized in that, It includes an outer tube (1), an inner tube (2), an inlet tube (3), a multi-way reversing valve (4), a first temperature sensor (5), a second temperature sensor (6), and a controller; The number of inner tubes (2) is several, which are arranged in parallel inside the outer tube (1). The liquid inlet pipe (3) is connected to the inlet of several inner tubes (2) through the multi-way reversing valve (4). The outer tube (1) is used to introduce the first fluid, and the liquid inlet pipe (3) is used to introduce the second fluid. The first temperature sensor (5) is installed at the inlet of the outer tube (1) to monitor the temperature of the first fluid, and the second temperature sensor (6) is installed at the outlet of the inlet tube (3) to monitor the temperature of the second fluid. The controller is electrically connected to the multi-way reversing valve (4), the first temperature sensor (5), and the second temperature sensor (6). The system assumes two temperature differences between the refrigerant and the cooling water: T1 and T2, where T1 < T2. Obtain the real-time temperature difference T between the refrigerant and the cooling water; When T≤T1, the three-inner-tube mode is adopted, and the first inner tube (21), the second inner tube (22) and the third inner tube (23) are all connected to the inlet tube (3); When T1 < T ≤ T2, the two inner tube mode is adopted, and any two of the first inner tube (21), the second inner tube (22), and the third inner tube (23) are connected to the liquid inlet tube (3); When T > T2, a single inner tube mode is adopted, and any one of the first inner tube (21), the second inner tube (22), and the third inner tube (23) is connected to the liquid inlet tube (3).

2. The three-pipe combination shell-and-tube heat exchanger according to claim 1, characterized in that: The first fluid is a refrigerant, and the second fluid is cooling water.

3. The three-pipe combination shell-and-tube heat exchanger according to claim 2, characterized in that: The inner tube (2) is a copper tube, and the inner tube (2) is equipped with an ion monitor (7) for monitoring the concentration of copper ions in the water. The ion monitor (7) is electrically connected to the controller.

4. The three-pipe combination shell-and-tube heat exchanger according to claim 1, characterized in that: The flow direction of the first fluid is opposite to that of the second fluid.

5. The three-pipe combination shell-and-tube heat exchanger according to claim 1, characterized in that: The inner tube (2) is a spiral tube.

6. The three-pipe combination shell-and-tube heat exchanger according to claim 3, characterized in that: The inner tube (2) includes a first inner tube (21), a second inner tube (22) and a third inner tube (23), and the multi-way reversing valve (4) is a four-way reversing valve.

7. A control method applied to the three-pipe combination shell-and-tube heat exchanger as described in claim 6, characterized in that, Includes the following steps: The system assumes two temperature differences between the refrigerant and the cooling water: T1 and T2, where T1 < T2. Obtain the real-time temperature difference T between the refrigerant and the cooling water; When T≤T1, the three-inner-tube mode is adopted, and the first inner tube (21), the second inner tube (22) and the third inner tube (23) are all connected to the liquid inlet tube (3); When T1 < T ≤ T2, the two inner tube mode is adopted, and any two of the first inner tube (21), the second inner tube (22), and the third inner tube (23) are connected to the liquid inlet tube (3); When T > T2, a single inner tube mode is adopted, and any one of the first inner tube (21), the second inner tube (22), and the third inner tube (23) is connected to the liquid inlet tube (3).

8. The control method for the three-pipe combined shell-and-tube heat exchanger according to claim 7, characterized in that: Preset cooling water copper ion concentration c0; When the inner tube (2) is connected to the liquid inlet tube (3), the real-time concentration c of copper ions in the cooling water is obtained. If c > c0, the connection between the inner tube (2) and the liquid inlet tube (3) is disconnected.

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