Low-temperature freeze-proof self-adaptive heat exchange device

Abstract

The application discloses a low-temperature anti-freezing self-adaptive heat exchange device and relates to the technical field of heat exchangers. The low-temperature anti-freezing self-adaptive heat exchange device comprises a heat exchange assembly, the heat exchange assembly comprises a fixedly arranged heat preservation shell, a heat exchange cavity for heat medium transmission, a first transmission cavity for cold medium input and a second transmission cavity for cold medium output are respectively formed in the heat preservation shell, a first pipe passage connecting pipe is fixed to the heat preservation shell and is communicated with the first transmission cavity, a second pipe passage connecting pipe is fixed to the heat preservation shell and is communicated with the second transmission cavity, a first shell passage connecting pipe is fixed to the heat preservation shell and is communicated with the heat exchange cavity, a second shell passage connecting pipe is fixed to the heat preservation shell and is communicated with the heat exchange cavity, and a tube plate and a partition plate are both fixed in the heat preservation shell. The metal bellows expansion joint is arranged to be temperature-sensing self-adaptive, the flow section of the heat tracing pipe is adjusted through the driving of the movable plate and the slide rod on the sealing plate, the automatic adjustment of the anti-freezing heat according to the temperature is realized, the continuous full-load heating is avoided, and the energy consumption is remarkably reduced.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger technology, and in particular to a low-temperature antifreeze adaptive heat exchange device. Background Technology

[0002] A heat exchanger (also called a heat exchanger) is a general-purpose heat transfer device that transfers heat between two or more fluids at different temperatures and realizes the exchange of heat between hot and cold media. It can complete the heating, cooling, condensation, evaporation and waste heat recovery of fluids. In the heat transfer process, the hot and cold fluids generally do not come into contact with each other, and the heat transfer is completed only through heat conduction and convection through the solid wall. Among them, shell and tube heat exchangers are commonly used.

[0003] Existing heat exchangers generally consist of a shell, tube sheet, heat exchange tube bundle, and baffles. Hot and cold fluids flow in the tube side and shell side respectively, with heat transfer occurring through the tube walls. When such heat exchangers are used in low-temperature environments or to handle easily frozen media, if the ambient temperature is too low or the shell side heating is insufficient, the cold medium in the tube side may experience a drop in temperature to near its freezing point, a sharp increase in viscosity, or even localized freezing, leading to a decrease in heat exchange efficiency. In severe cases, this can even cause blockage of the flow channels or damage to the heat exchange tubes. To maintain normal operation under low-temperature conditions, existing heat exchangers typically employ heat tracing lines or add electric heaters at the shell-side inlet. The heat tracing lines continuously supply hot medium to maintain the tube-side temperature, while the electric heaters heat the shell-side fluid. In practical applications, these anti-freezing measures often rely on continuous heating or manual start-stop methods. When the ambient temperature changes, the heating amount is not easily adjusted automatically according to actual needs, potentially resulting in high energy consumption or delayed temperature rise response. Furthermore, there is still a risk of localized overcooling under extreme low temperatures. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the above and / or existing low-temperature antifreeze adaptive heat exchange devices, the present invention is proposed.

[0006] Therefore, the problem to be solved by this invention is how to address the issues of existing heat exchangers' inability to adaptively adjust antifreeze heating in low-temperature environments, high energy consumption, and delayed temperature rise response.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a low-temperature antifreeze adaptive heat exchange device, comprising a heat exchange assembly, the heat exchange assembly including a fixedly disposed insulation shell, wherein the insulation shell is respectively provided with a heat exchange cavity for transmitting a heating medium, a first transmission cavity for inputting a cold medium, and a second transmission cavity for outputting a cold medium, a first tube-side connecting pipe fixed to the insulation shell and communicating with the first transmission cavity, a second tube-side connecting pipe fixed to the insulation shell and communicating with the second transmission cavity, a first shell-side connecting pipe fixed to the insulation shell and communicating with the heat exchange cavity, a second shell-side connecting pipe fixed to the insulation shell and communicating with the heat exchange cavity, and a tube sheet and a partition plate both fixed inside the insulation shell for connecting the heat exchange cavity, the first transmission cavity, and the second transmission cavity. The insulation shell is divided into a baffle plate fixed inside the insulation shell and a U-shaped heat exchange tube fixed to the tube sheet. The U-shaped heat exchange tube passes through the baffle plate. An adjustment component is set on one side of the insulation shell. The adjustment component includes an injection shell fixed in the first transmission chamber, a return shell fixed in the second transmission chamber, and a heat tracing tube fixed between the injection shell and the return shell. The heat tracing tube is located inside the U-shaped heat exchange tube. A driving component is set on the outside of the insulation shell. A heating component is set at the input end of the first shell-side pipe. The heat tracing tube is set inside the U-shaped heat exchange tube and connects the injection shell and the return shell to form a heat tracing circuit. The driving component adjusts the flow rate of the heat tracing medium by driving the sealing plate through the movable plate according to the temperature change. The heating component heats the shell-side medium in conjunction with the temperature at the input end of the first shell-side pipe.

[0008] As a preferred embodiment of the low-temperature antifreeze adaptive heat exchange device of the present invention, wherein: an auxiliary cavity is provided inside the liquid injection shell, one end of the heat tracing pipe is connected to the auxiliary cavity, the other end of the heat tracing pipe is connected to the inner cavity of the return liquid shell, and a return liquid pipe connected to an external heat return source is fixed on the return liquid shell.

[0009] As a preferred embodiment of the low-temperature antifreeze adaptive heat exchange device of the present invention, wherein: a sealing cavity is provided on one side of the auxiliary cavity, an expansion cavity is provided on one side of the sealing cavity, and an injection pipe connected to an external heat source is fixed on the injection shell.

[0010] As a preferred embodiment of the low-temperature antifreeze adaptive heat exchange device of the present invention, the driving component includes two fixed frames fixed on the insulation shell, and a positioning rod is disposed on the fixed frame.

[0011] As a preferred embodiment of the low-temperature antifreeze adaptive heat exchange device of the present invention, the driving component further includes a movable plate disposed between two fixed frames, the movable plate having a positioning hole, an angle sensor being fixed in the positioning hole by screws, and one end of the positioning rod being fixed to the detection end of the angle sensor.

[0012] As a preferred embodiment of the low-temperature antifreeze adaptive heat exchange device of the present invention, the driving component further includes a sealing plate slidably connected in the sealing cavity, the outer ring of the sealing plate is sealed with the inner wall of the sealing cavity, and the slide rod is fixed at the center of one side of the sealing plate.

[0013] As a preferred embodiment of the low-temperature antifreeze adaptive heat exchange device of the present invention, a temperature-resistant spring is sleeved on the slide rod, one end of the temperature-resistant spring is fixed to the sealing plate, and the other end of the temperature-resistant spring is fixed to the liquid injection shell.

[0014] As a preferred embodiment of the low-temperature antifreeze adaptive heat exchange device of the present invention, the slide rod extends to the outside of the auxiliary cavity at the end away from the sealing plate and is ball-jointed to a first dovetail block. The connection between the slide rod and the auxiliary cavity is slidably connected and sealed. A first dovetail groove is provided on the movable plate for the first dovetail block to slide.

[0015] As a preferred embodiment of the low-temperature antifreeze adaptive heat exchange device of the present invention, the driving component further includes a metal bellows expansion joint fixed on the insulation shell, the moving end of the metal bellows expansion joint is ball-jointed to a second dovetail block, and a second dovetail groove is provided on the movable plate for the second dovetail block to slide.

[0016] As a preferred embodiment of the low-temperature antifreeze adaptive heat exchange device of the present invention, the heating component includes an insulation pipe fixed on the first shell-side connecting pipe, an electric heating grid fixed inside the insulation pipe, and the end of the insulation pipe away from the first shell-side connecting pipe is connected to the heat medium source.

[0017] The beneficial effects of this invention are as follows: By setting a temperature-sensitive adaptive expansion joint for the metal bellows, the flow cross-section of the heat tracing pipe is adjusted by the movable plate and sliding rod driving the sealing plate, thereby achieving automatic temperature-dependent adjustment of the antifreeze heat, avoiding continuous full-load heating, and significantly reducing energy consumption; when the temperature drops further, the angle sensor detects the rotation angle of the movable plate and automatically starts the electric heating grid to promptly replenish the temperature of the shell-side fluid, with a rapid response, eliminating the risk of local overcooling caused by lag in temperature rise under extreme low temperatures; the heat tracing pipe is built into the U-shaped heat exchange tube, and the antifreeze heat acts directly on the tube-side medium, with a clear antifreeze effect, ensuring the overall heat exchange efficiency under low-temperature conditions. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1This is a structural diagram of a low-temperature antifreeze adaptive heat exchanger.

[0020] Figure 2 This is a cross-sectional view of a low-temperature antifreeze adaptive heat exchanger.

[0021] Figure 3 This is a half-section perspective view of a low-temperature antifreeze adaptive heat exchange device.

[0022] Figure 4 This is a structural diagram of the regulating component and the heating component of a low-temperature antifreeze adaptive heat exchange device.

[0023] Figure 5 This is a schematic diagram of the regulating components of a low-temperature antifreeze adaptive heat exchanger.

[0024] Figure 6 Low-temperature antifreeze adaptive heat exchanger Figure 5 Enlarged view of point A in the middle.

[0025] In the diagram: 1. Heat exchange assembly; 11. Insulation shell; 111. Heat exchange chamber; 112. First transfer chamber; 113. Second transfer chamber; 12. First tube-side connector; 13. Second tube-side connector; 14. First shell-side connector; 15. Second shell-side connector; 16. Tube sheet; 17. Baffle; 18. Baffle plate; 19. U-shaped heat exchange tube; 2. Adjustment assembly; 21. Liquid injection shell; 211. Auxiliary chamber; 212. Sealing chamber; 213. Expansion chamber; 214. Liquid injection pipe; 22. Liquid return shell; 221. Return... 23. Liquid pipe; 24. Heat tracing pipe; 25. Drive component; 26. Fixing frame; 27. Positioning rod; 28. Movable plate; 29. ​​Positioning hole; 20. First dovetail groove; 20. Second dovetail groove; 21. Angle sensor; 22. Sealing plate; 23. Guide rod; 24. Slide rod; 24.6. Temperature-resistant spring; 24. First dovetail block; 24. Metal bellows expansion joint; 24. Second dovetail block; 30. Heating component; 31. Insulation pipe; 32. Electric heating grid. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] Example 1, referring to Figure 1 and Figure 2 This is the first embodiment of the present invention. This embodiment provides a low-temperature antifreeze adaptive heat exchange device, which includes a heat exchange component 1, an adjustment component 2 and a heating component 3.

[0030] Specifically, the heat exchange assembly 1 includes a fixedly installed insulation shell 11. The insulation shell 11 has a heat exchange chamber 111 for transmitting the heating medium, a first transmission chamber 112 for inputting the cold medium, and a second transmission chamber 113 for outputting the cold medium. A first tube-side connecting pipe 12 is welded to the insulation shell 11 and communicates with the first transmission chamber 112. A second tube-side connecting pipe 13 is welded to the insulation shell 11 and communicates with the second transmission chamber 113. A first shell-side connecting pipe 14 is welded to the insulation shell 11 and communicates with the heat exchange chamber 111. A second shell-side connecting pipe 15 is welded to the insulation shell 11 and communicates with the heat exchange chamber 111. A tube sheet 16 and a baffle 17 are both welded inside the insulation shell 11 to separate the heat exchange chamber 111, the first transmission chamber 112, and the second transmission chamber 113. A baffle 18 is welded inside the insulation shell 11. A U-shaped heat exchange tube 19 is fixed to the tube sheet 16 and passes through the baffle 18.

[0031] Specifically, the adjustment component 2 is located on one side of the insulation shell 11. The adjustment component 2 includes an injection shell 21 welded to the first transmission cavity 112, a return shell 22 welded to the second transmission cavity 113, a heat tracing pipe 23 fixed between the injection shell 21 and the return shell 22, the heat tracing pipe 23 being located inside the U-shaped heat exchange pipe 19, and a driving component 24 being located outside the insulation shell 11.

[0032] Specifically, the heating component 3 is fixed to the input end of the first shell-side pipe 14 via a flange.

[0033] Example 2, refer to Figures 2-6 This is the second embodiment of the present invention, which is based on the previous embodiment.

[0034] Specifically, an auxiliary cavity 211 is provided inside the injection shell 21. One end of the heat tracing pipe 23 is connected to the auxiliary cavity 211, and the other end of the heat tracing pipe 23 is connected to the inner cavity of the return shell 22. A return pipe 221 connected to an external heat source is fixed on the return shell 22. The medium returning through the return pipe 221 re-enters the external heating device, which is connected to the injection pipe 214, thereby maintaining the medium entering the injection shell 21 at a suitable temperature range.

[0035] Specifically, a sealing cavity 212 is provided on one side of the inner cavity of the auxiliary cavity 211, and an expansion cavity 213 is provided on one side of the inner cavity of the sealing cavity 212. An injection pipe 214 connected to an external heat source is fixed on the injection shell 21.

[0036] Specifically, the drive component 24 includes two fixing brackets 241 bolted to the insulation shell 11, and a positioning rod 242 is disposed on the fixing brackets 241.

[0037] Specifically, the drive component 24 also includes a movable plate 243 disposed between two fixed brackets 241. The movable plate 243 has a positioning hole 2431. An angle sensor 244 is fixed in the positioning hole 2431 with screws. One end of the positioning rod 242 is fixed to the detection end of the angle sensor 244.

[0038] Specifically, the driving component 24 also includes a sealing plate 245 slidably connected to the sealing cavity 212. The outer ring of the sealing plate 245 is sealed to the inner wall of the sealing cavity 212. A slide rod 246 is welded to the center of one side of the sealing plate 245. A heat-resistant spring 2461 is sleeved on the slide rod 246. One end of the heat-resistant spring 2461 is fixed to the sealing plate 245, and the other end of the heat-resistant spring 2461 is fixed to the liquid injection shell 21.

[0039] A guide rod 2451 is welded to one side of the sealing plate 245. The end of the guide rod 2451 away from the sealing plate 245 passes through the auxiliary cavity 211. The guide rod 2451 slides in contact with the auxiliary cavity 211 and is sealed. The guide rod 2451 is used to guide and ensure the stability of the slide rod 246.

[0040] Specifically, the end of the slide rod 246 away from the sealing plate 245 extends to the outside of the auxiliary cavity 211 and is ball-jointed to the first dovetail block 247. The connection between the slide rod 246 and the auxiliary cavity 211 is slidably connected and sealed. The movable plate 243 has a first dovetail groove 2432 for the first dovetail block 247 to slide.

[0041] Specifically, the drive component 24 also includes a metal bellows expansion joint 248 bolted to the insulation shell 11. The moving end of the metal bellows expansion joint 248 is ball-jointed to a second dovetail block 249. The movable plate 243 has a second dovetail groove 2433 for sliding the second dovetail block 249.

[0042] The metal bellows expansion joint 248 includes a fixed end connector: sealing one end of the bellows and used for installation and fixation, which in this embodiment is fixed to the insulation shell 11; a movable end connector: sealing the other end and connecting to the output rod or directly serving as the movable end, which in this embodiment is connected to the second dovetail block 249 by a ball joint; a metal bellows: a thin-walled metal tube formed by hydraulic or mechanical expansion, with multiple annular corrugations, which can expand and contract axially, and has both elasticity and sealing properties; a temperature-sensitive working fluid: the sealed cavity is filled with a medium with a large coefficient of thermal expansion and sensitive to temperature, such as a low-boiling-point liquid, inert gas, paraffin / thermally sensitive wax mixture, etc., and the expansion and contraction of the bellows is driven by the volume change of the working fluid.

[0043] Correspondingly, when the temperature decreases: the working fluid volume shrinks, and the internal pressure decreases. Under the combined action of its own elasticity and external atmospheric pressure, the bellows shortens and contracts axially, and the moving end moves inward; when the temperature increases: the working fluid volume expands, and the internal pressure increases, overcoming the bellows' elasticity and causing it to lengthen axially, and the moving end moves outward.

[0044] In practical applications, in order to ensure the stability of the movement of the moving end of the metal bellows expansion joint 248, a crossbar is fixed on the fixed end of the metal bellows expansion joint 248, and the crossbar passes through the moving end and slides in contact with the moving end.

[0045] Specifically, the heating component 3 includes an insulation pipe 31 fixed to the first shell-side connecting pipe 14, an electric heating mesh 32 bolted inside the insulation pipe 31, and the end of the insulation pipe 31 away from the first shell-side connecting pipe 14 connected to the heat medium source.

[0046] Example 3, referring to Figures 2-6 This is the third embodiment of the present invention, which is based on the first two embodiments.

[0047] like Figure 5 As shown, the outer ring of the positioning rod 242 has a first thread, and the corresponding fixing frame 241 has a second thread that mates with the first thread. The first thread and the second thread mate to stably install the positioning rod 242 on the fixing frame 241. The positioning rod 242 is smooth except for the first thread, and is used to be inserted into the positioning hole 2431 to position the rotating movable plate 243.

[0048] By cooperating with the positioning rod 242 and the positioning holes 2431 at different positions, the lever arms at both ends of the movable plate 243 can be changed. Thus, under the premise that the metal bellows expansion joint 248 moves the same distance, the movement distance of the slide rod 246 is changed accordingly, which is suitable for a variety of usage needs.

[0049] In practical applications, a distribution branch pipe is set at the outlet of the liquid injection shell 21 and connected to each heat tracing pipe 23, and a corresponding collection branch pipe is set at the return liquid shell 22 to achieve uniform distribution and convergence.

[0050] In practical applications, a foldable protective cover is installed on the outside of the metal bellows expansion joint 248 to protect the metal bellows expansion joint 248 when the device is not in use.

[0051] In practical applications, the angle sensor 244 is replaced with a non-contact type such as Hall effect or photoelectric sensor. The sensor stator is fixed to the movable plate 243, and the rotor is connected to the positioning rod 242, eliminating the need for a drag cable. See the detailed description below.

[0052] In practical applications, the electric heating mesh 32 is replaced with a detachable flange-type electric heating tube bundle, which meets the requirements for explosion-proof and pressure resistance. A temperature sensor and a flow switch are added to the insulation tube 31. The angle sensor 244 signal serves as a pre-start condition, and the flow switch must confirm the presence of the shell-side medium. The shell-side outlet temperature can be taken from the second shell-side pipe 15 to form PID control (see the detailed description below) to prevent overheating. An over-temperature protection switch and ground fault protection are added to the power supply circuit of the electric heating tube bundle to meet electrical safety standards.

[0053] It should be noted that an exhaust valve with a plug is added to the upper part of the insulation shell 11 and the high point of the first shell-side pipe 14 to facilitate exhaust during start-up and shutdown; a drain connector is set at the lowest point of the heat exchange chamber 111, and a drain port is added at the lower part of the first transmission chamber 112. Both the drain connector and the drain port are normally closed.

[0054] During operation, under normal heat exchange conditions, the cold medium enters the first transfer chamber 112 through the first tube-side connector 12, is distributed by the tube sheet 16, flows into each U-shaped heat exchange tube 19, absorbs heat, and then flows into the second transfer chamber 113, from which it is discharged. Simultaneously, the hot medium enters the heat exchange chamber 111 from the insulation tube 31 of the heating assembly 3 through the first shell-side connector 14. Guided by the baffle 18, it repeatedly washes the outer wall of the U-shaped heat exchange tube 19 and releases heat, finally being discharged through the second shell-side connector 15. The cold and hot media complete non-contact, high-efficiency heat exchange through the tube wall.

[0055] Under low-temperature conditions, when the outside temperature drops to a certain level, the metal bellows expansion joint 248 in the drive component 24 contracts upon sensing the cold. Its moving end drives the second dovetail block 249 to move laterally inward, driving the movable plate 243 to rotate around the positioning rod 242. During this process, the first dovetail block 247 slides within the first dovetail groove 2432, causing the slide rod 246 to move linearly outward, thereby pulling the sealing plate 245 to overcome the elastic force of the heat-resistant spring 2461 and slide from the sealing cavity 212 into the expansion cavity 213. At this time, the positive pressure warm medium introduced through the injection pipe 214 can enter the auxiliary cavity 211 through the expansion cavity 213 and the sealing cavity 212, and then flow into the heat tracing pipe 23. The heat from the heat tracing pipe 23 is directly transferred to the cold medium in the U-shaped heat exchange tube 19. As the temperature decreases, the flow rate of the heat tracing medium automatically increases, achieving stepless adaptive temperature regulation, avoiding overheating and reducing energy consumption.

[0056] If the temperature drops further, the metal bellows expansion joint 248 continues to contract, and the rotation angle of the movable plate 243 increases. When the angle sensor 244 detects that the rotation angle has reached the preset value, it sends a signal, and the electric heating grid 32 is then energized to actively heat the heat medium at the shell-side inlet, ensuring that the medium entering the heat exchange chamber 111 has a sufficient temperature, completely eliminating the risk of temperature lag and local overcooling under extreme conditions, and maintaining the overall heat exchange efficiency.

[0057] After heat exchange is completed, the heat tracing medium is returned to the external heating equipment for recycling via the return pipe 221 of the return liquid shell 22. When the device is shut down, the external negative pressure equipment can be connected to the interfaces of the first tube side connector 12, the second shell side connector 15, or the liquid injection pipe 214 to actively evacuate the residual medium in the system and prevent the residual liquid from freezing and causing damage to components during idle periods.

[0058] The following is a further explanation of the sensing and PID control in this application.

[0059] This invention, a low-temperature antifreeze adaptive heat exchange device, differs from traditional fixed heat exchange and temperature control equipment. Its core innovation lies in relying on a high-precision angle sensing and detection system and an adaptive PID intelligent control algorithm to achieve stepless antifreeze temperature regulation and precise temperature control under low-temperature conditions. This solves the technical pain points of traditional equipment, such as lag in temperature control, overheating, poor low-temperature adaptability, and high energy consumption. The following section provides a comprehensive and detailed explanation of the device's angle sensing and detection driver program, PID control algorithm operation mechanism, parameter value logic, and overall control effect. It also clarifies the differentiated advantages compared to traditional detection and control schemes, thus perfecting the core technology system of the device's intelligent low-temperature antifreeze system.

[0060] (I) Angle sensing and driving

[0061] 1.1 Hardware Configuration

[0062] The angle sensor 244 in this device adopts an upgradeable non-contact Hall / photoelectric sensing structure, replacing the traditional contact angle sensor. The stator is fixed to the movable plate 243, and the rotor is rigidly connected to the positioning rod 242, completely eliminating the need for a drag cable and avoiding problems such as cable hardening and breakage and poor contact in low-temperature environments. The core detection object of the sensor is the real-time rotation angle of the movable plate 243. This angle has a linear correlation with the expansion and contraction displacement of the metal bellows expansion joint 248 and the degree of ambient low temperature. It is the core feedback signal for the device to determine low-temperature operating conditions and trigger heat tracing adjustment and electric heating auxiliary heating.

[0063] Based on the mechanical structure characteristics of the device, the assembly and cooperation of the positioning rod 242 with different positioning holes 2431 can adjust the lever arms at both ends of the movable plate 243. Under the same extension and retraction displacement of the bellows, the rotation angle of the movable plate can achieve differentiated output. The angle sensor can accurately capture this subtle angle change, and the detection range is adapted to the rotation range of 0°~35° low temperature working conditions, fully covering the equipment adjustment stroke from normal temperature to extreme low temperature.

[0064] 1.2 Sensor Drive Process

[0065] This device is equipped with a dedicated embedded driver program (driven by a PLC or MCU microcontroller, microserver, etc. mounted on the heat exchanger itself; the main control device of the heat exchanger can refer to the composition of existing heat exchangers, such as various types of heat exchangers currently on the market, whose main control system consists of a sensing layer (sensors), a control layer (PLC / controller), an execution layer (valve / frequency converter), a human-machine interface layer (HMI), and a communication network. The control layer (brain processing): with a PLC (programmable logic controller) as the core, it has built-in PID and other algorithm modules to process feedback signals and output control commands; some high-end systems integrate edge computing or AI optimization modules, etc. The specific composition will not be elaborated here), realizing real-time acquisition, filtering and calibration, signal output, and threshold determination of angle signals. The specific operation logic is divided into four steps:

[0066] First, real-time sampling: the driver program is set to a fixed sampling period of 10ms to continuously read the pulse voltage signal of the non-contact sensor, converting the analog mechanical rotation angle into a digital electrical signal to complete the acquisition of the raw angle data.

[0067] Second, data filtering calibration: In response to noise signals generated by electromagnetic interference and mechanical micro-vibration in low-temperature environments, a mean filtering algorithm is adopted. Ten sets of angle data are continuously collected, and the maximum and minimum values ​​are removed before taking the average value to eliminate detection errors and ensure data stability.

[0068] Third, signal conversion: based on the angle-displacement-temperature correspondence curve calibrated by the equipment, the real-time angle data is converted into ambient temperature, corrugated pipe expansion and contraction, and heat tracing pipe medium flow opening parameters.

[0069] Fourth, threshold output judgment: the program has a built-in preset angle threshold. When the detected angle does not reach the threshold, only mechanical adaptive heating adjustment is maintained; when the angle reaches the preset antifreeze threshold, a high-level trigger signal is output to activate the auxiliary electric heating function of the heating component.

[0070] Traditional heat exchange and antifreeze equipment mostly uses on-off displacement sensors or fixed threshold temperature sensors, which can only achieve a rough detection of "starting and stopping when the standard is met" and cannot capture the subtle adjustment during the gradual change of low temperature. This results in problems such as adjustment lag and abrupt gear switching. In addition, traditional contact angle sensors are easily affected by low temperature freezing and mechanical friction, resulting in rapid decline in detection accuracy and high failure rate.

[0071] The angle sensing detection system of this solution has three core advantages: First, it is a non-contact detection system with no mechanical wear, strong low-temperature adaptability, and stable detection accuracy; second, continuous angle sampling can achieve stepless signal output and the matching device has stepless adaptive temperature adjustment characteristics; third, it can adapt to multiple working conditions through lever arm adjustment, and the detection range can be flexibly adapted to different low-temperature environments, making it far more versatile than traditional fixed detection solutions.

[0072] (II) Adaptive PID Control

[0073] Traditional heat exchange equipment uses fixed-parameter PID control, with parameters locked at the factory. This makes it unable to adapt to dynamic changes in ambient temperature and medium flow rate, leading to problems such as insufficient temperature rise at low temperatures, overheating at high temperatures, and poor parameter adaptability. Furthermore, traditional solutions lack a pre-judgment mechanism, rely on continuous closed-loop control throughout the process, resulting in high ineffective energy consumption, and lack flow interlock protection, leading to low equipment operational safety.

[0074] This device abandons the traditional fixed-parameter PID control mode and adopts an angle pre-judgment + temperature and flow closed-loop adaptive PID control algorithm. It uses the angle sensor detection signal as the pre-start condition and the medium temperature at the second shell-side inlet pipe 15 and the pipeline flow switch signal as the closed-loop feedback basis to achieve precise temperature control of the electric heating components, completely eliminating overheating, temperature lag, and dry-burning faults. The overall algorithm operation logic is as follows: Under low-temperature conditions, the angle sensor transmits the rotation angle signal in real time. The system predicts the low-temperature anti-freezing requirements, combines the flow switch to determine the shell-side medium flow status, and after confirming normal heat exchange conditions, it collects the real-time shell-side outlet temperature and compares it with the set anti-freezing reference temperature. The PID algorithm dynamically adjusts the output power of the electric heating tube bundle, corrects the heating amount in real time, maintains a stable heat exchange medium temperature, and achieves low-temperature adaptive anti-freezing temperature control.

[0075] The algorithm principle is as follows:

[0076] Unlike traditional PID algorithms, this device employs an incremental PID control algorithm, which is adapted to the overshoot-free and high-precision control requirements of electric heating tube bundle power regulation. Its expression is defined as follows:

[0077]

[0078]

[0079] In the formula:

[0080] 1. The heating power adjustment increment for the kth sampling period, in W, represents the power correction amount for a single adjustment, with a value range of 0~50W. This is adapted to the fine-tuning requirements of the small electric heating tube bundle in this device, avoiding temperature fluctuations caused by sudden power changes.

[0081] 2. The real-time output power of the electric heating in the kth sampling period. The output power of the previous cycle is expressed in W, with a power adjustment range of 0~500W. The pressure-bearing and explosion-proof design parameters of the insulation pipe 31 of the matching device are also specified.

[0082] 3. Temperature deviation value in the kth sampling period ; Set a reference temperature for the medium's antifreeze function, and set a fixed value of 5℃ according to the equipment's low-temperature antifreeze requirements to ensure that the medium has no risk of freezing. The real-time medium temperature detected by the second shell-side connector 15 is in °C. , These are the temperature deviation values ​​for the first and second sampling periods, respectively.

[0083] 4. The proportional gain is used to quickly respond to temperature deviations and shorten the control response time. In this device, it is set to 3.2. The rationale for this value is that low-temperature heat exchange systems exhibit strong temperature lag; a suitable proportional gain can prevent overheating due to excessively fast response, while ensuring rapid power adjustment when low-temperature deviations occur.

[0084] 5. The integral coefficient is used to eliminate steady-state temperature errors and solve the problem of temperature control deviation under long-term low-temperature conditions. This device uses a value of 0.08. The reason for this value is that the temperature fluctuation of the heat exchange medium is gradual, and a small integral coefficient can accurately correct static deviations while avoiding temperature oscillations caused by integral accumulation.

[0085] 6. The differential coefficient is used to predict temperature change trends and suppress sudden temperature drops under extreme low temperatures. In this device, it is set to 0.5. The rationale for this value is that the medium temperature drops rapidly under extreme low-temperature conditions. The differential coefficient can predict the cooling trend in advance, allowing for increased heating power and eliminating heating lag.

[0086] In addition, it is equipped with decision logic and safety mechanisms: the PID controller adds dual pre-decision conditions, which is different from the traditional single temperature closed-loop control.

[0087] The first is the angle prediction condition. The PID temperature control program is only started when the angle sensor detects that the angle has reached the preset antifreeze threshold and confirms that the environment is in a low-temperature condition. Under normal temperature conditions, the electric heating control is turned off to reduce energy consumption.

[0088] The second condition is the flow interlock. The algorithm only executes power adjustment after the flow switch detects normal flow of the shell-side medium. If there is no medium flow in the pipeline, the heating power is locked to 0 to prevent dry burning and overheating damage to the equipment. At the same time, the algorithm integrates over-temperature protection logic. When the detected medium temperature exceeds 30°C, the heating power is forcibly cut off, achieving dual safety protection.

[0089] The optimized adaptive PID algorithm in this solution features several innovations: First, it introduces angle pre-judgment to achieve "on-demand control," distinguishing between normal temperature, low temperature, and extreme low temperature operating conditions, and selectively activating temperature control logic to significantly reduce ineffective energy consumption. Second, it adapts parameters to low-temperature heat exchange scenarios, solving the problems of temperature control lag and temperature oscillation in traditional algorithms through refined proportional, integral, and derivative parameter values. Third, it adds dual interlock protection for flow and temperature, meeting explosion-proof and pressure-bearing industrial standards, with safety far exceeding traditional control solutions. Fourth, dynamic incremental control enables stepless power fine-tuning, matching the stepless adaptive temperature regulation characteristics of the device's machinery, with temperature control accuracy error controlled within ±0.8℃, far superior to the ±2℃ temperature control accuracy of traditional PID.

[0090] In summary, this device achieves deep integration of mechanical adaptive temperature control and intelligent electronic temperature control by optimizing the angle sensor detection drive logic and adaptive PID control algorithm. Under normal low-temperature conditions, it relies on high-precision angle sensor detection to capture changes in ambient temperature and uses a mechanical structure to steplessly adjust the flow rate of the heat tracing pipe medium, achieving passive anti-freeze temperature control. Under extreme low-temperature conditions, the angle signal triggers the PID intelligent temperature control system, dynamically adjusting the electric heating power and actively compensating for heat exchange temperature loss. The entire system solves the defects of traditional low-temperature heat exchange equipment, such as coarse temperature control, high energy consumption, poor stability, and susceptibility to freezing. It achieves adaptive, high-precision, and low-energy-consumption anti-freeze heat exchange under all low-temperature conditions, ensuring continuous and stable operation of the equipment in low-temperature environments, while meeting the requirements for industrial explosion-proof, electrical safety, and long-term stable operation.

[0091] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A low-temperature antifreeze adaptive heat exchange device, characterized in that: The system includes a heat exchange assembly (1), which includes a fixedly installed insulation shell (11). The insulation shell (11) has a heat exchange chamber (111) for heat transfer medium, a first transmission chamber (112) for cold medium input, and a second transmission chamber (113) for cold medium output. A first tube-side connector (12) is fixed to the insulation shell (11) and communicates with the first transmission chamber (112). The second tube-side connector (13) is fixed to the insulation shell (11) and communicates with the second transmission chamber (113). The cavity (113) is connected, the first shell-side pipe (14) is fixed on the insulation shell (11) and connected to the heat exchange cavity (111), the second shell-side pipe (15) is fixed on the insulation shell (11) and connected to the heat exchange cavity (111), the tube sheet (16) and the baffle (17) are both fixed inside the insulation shell (11) to separate the heat exchange cavity (111), the first transfer cavity (112) and the second transfer cavity (113), and the baffle (18) is fixed inside the insulation shell (11). U-shaped heat exchange The tube (19) is fixed on the tube sheet (16). The U-shaped heat exchange tube (19) passes through the baffle plate (18). The adjustment assembly (2) is set on one side of the insulation shell (11). The adjustment assembly (2) includes an injection shell (21) fixed in the first transmission chamber (112), a return shell (22) fixed in the second transmission chamber (113), and a heat tracing tube (23) fixed between the injection shell (21) and the return shell (22). The heat tracing tube (23) is located inside the U-shaped heat exchange tube (19). The driving component (24) is located on the outside of the insulation shell (11), the heating component (3) is located at the input end of the first shell-side pipe (14), the heat tracing pipe (23) is located inside the U-shaped heat exchange pipe (19) and connects the liquid injection shell (21) and the liquid return shell (22) to form a heat tracing circuit. The driving component (24) adjusts the flow of the heat tracing medium by driving the sealing plate (245) through the movable plate (243) according to the temperature change. The heating component (3) heats the shell-side medium in conjunction with the input end of the first shell-side pipe (14).

2. The low-temperature antifreeze adaptive heat exchange device as described in claim 1, characterized in that: An auxiliary cavity (211) is provided inside the injection shell (21). One end of the heat tracing pipe (23) is connected to the auxiliary cavity (211), and the other end of the heat tracing pipe (23) is connected to the inner cavity of the return shell (22). A return pipe (221) connected to an external heat source is fixed on the return shell (22).

3. The low-temperature antifreeze adaptive heat exchange device as described in claim 2, characterized in that: A sealing cavity (212) is provided on one side of the inner cavity of the auxiliary cavity (211), and an expansion cavity (213) is provided on one side of the inner cavity of the sealing cavity (212). An injection pipe (214) connected to an external heat source is fixed on the injection shell (21).

4. The low-temperature antifreeze adaptive heat exchange device as described in claim 1, characterized in that: The drive unit (24) includes two fixing brackets (241) fixed on the heat insulation shell (11), and a positioning rod (242) is set on the fixing brackets (241).

5. The low-temperature antifreeze adaptive heat exchange device as described in claim 4, characterized in that: The drive unit (24) also includes a movable plate (243) disposed between two fixed brackets (241). The movable plate (243) has a positioning hole (2431). An angle sensor (244) is fixed in the positioning hole (2431) with screws. One end of the positioning rod (242) is fixed to the detection end of the angle sensor (244).

6. The low-temperature antifreeze adaptive heat exchange device as described in claim 5, characterized in that: The driving component (24) also includes a sealing plate (245) slidably connected to the sealing cavity (212). The outer ring of the sealing plate (245) is sealed to the inner wall of the sealing cavity (212), and the slide rod (246) is fixed at the center of one side of the sealing plate (245).

7. The low-temperature antifreeze adaptive heat exchange device as described in claim 6, characterized in that: A heat-resistant spring (2461) is fitted on the slide rod (246). One end of the heat-resistant spring (2461) is fixed to the sealing plate (245), and the other end of the heat-resistant spring (2461) is fixed to the liquid injection shell (21).

8. The low-temperature antifreeze adaptive heat exchange device as described in claim 7, characterized in that: The sliding rod (246) extends away from the sealing plate (245) to the outside of the auxiliary cavity (211) and is ball-jointed with a first dovetail block (247). The sliding rod (246) and the auxiliary cavity (211) are slidably connected and sealed. The movable plate (243) has a first dovetail groove (2432) for the first dovetail block (247) to slide.

9. The low-temperature antifreeze adaptive heat exchange device as described in claim 8, characterized in that: The drive unit (24) also includes a metal bellows expansion joint (248) fixed on the heat insulation shell (11). The moving end of the metal bellows expansion joint (248) is ball-jointed to a second dovetail block (249). The movable plate (243) is provided with a second dovetail groove (2433) for the second dovetail block (249) to slide.

10. The low-temperature antifreeze adaptive heat exchange device as described in claim 1, characterized in that: The heating component (3) includes an insulation pipe (31) fixed on the first shell-side connector (14), an electric heating mesh (32) fixed inside the insulation pipe (31), and the end of the insulation pipe (31) away from the first shell-side connector (14) is connected to the heat medium source.

Images