A shell-and-tube heat exchanger

Abstract

This invention discloses a shell-and-tube heat exchanger, belonging to the field of heat exchanger technology, comprising: a heat exchanger body, a liquid inlet switching assembly, a pressure monitoring assembly, and a backwashing assembly. The liquid inlet switching assembly includes a first filtration branch and a second filtration branch, each branch equipped with a filter box and an on / off valve, with one branch selectively activated. The pressure monitoring assembly is located outside the filter box, with a trigger diaphragm and trigger rod cooperating to transmit the fluid pressure inside the filter box to a sensor. The backwashing assembly is located inside the filter box, including a filter screen, a backwashing unit located below the filter screen, and a drain unit located above the filter screen. When the pressure sensor of the working branch detects that the pressure reaches a preset value, the on / off valve of that branch closes and switches to the other branch, simultaneously shutting down the backwashing unit and drain unit of that branch for reverse flushing. After flushing, the system is restored to standby mode. This invention provides reliable condition monitoring and cleaning maintenance of the shell side without interrupting the heat exchanger and the main process flow.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger technology, and more particularly to a shell-and-tube heat exchanger. Background Technology

[0002] Shell-and-tube heat exchangers, as a classic type of indirect heat exchanger, are widely used in industries such as petrochemicals, energy and power, metallurgy, and pharmaceuticals due to their robust structure, high adaptability, and large throughput. Their core working principle involves two fluids at different temperatures flowing through the tubes and shell respectively, exchanging heat through the tube walls. However, in actual operation, especially when handling process fluids containing solid particles, prone to scaling, or polymers, their performance and reliability face continuous challenges.

[0003] In the application of shell-and-tube heat exchangers, a common and critical issue is controlling the cleanliness of the shell-side and tube-side fluids. From the shell-side perspective, when the shell-side medium is a liquid or gas containing impurities, catalyst particles, polymer oligomers, or easily fouling components, these impurities will gradually adhere to and deposit on the outer wall of the heat exchange tubes, baffles, and the inner wall of the shell, forming a fouling layer. The presence of a fouling layer significantly increases the thermal resistance, leading to a continuous decline in heat exchange efficiency. At the same time, the reduction in the cross-sectional area of ​​the flow channel will cause an increase in the shell-side pressure drop, increasing pumping energy consumption. In severe cases, uneven blockage can also lead to uneven fluid distribution, induce tube bundle vibration, and even cause heat exchange tube wear and leakage, seriously affecting the long-term safe and stable operation of the unit.

[0004] To address the aforementioned issues, existing technologies primarily offer solutions from three levels: first, filtering at the source; second, offline cleaning; and third, online cleaning.

[0005] Source filtration is the most direct way to prevent impurities from entering the shell side. For example, the patent application CN202421035024, "A Heat Exchanger that Can Be Cleaned Without Stopping Operation," achieves cleaning without stopping operation by installing valves on both sides of the filter and adding a bypass valve, thus avoiding system shutdown affecting operation. It also employs a linkage structure of a drive ring, toothed ring, and threaded cylinder, allowing multiple fixing points to be loosened simultaneously, improving end cover disassembly efficiency. However, the cleaning process still requires manual operation of valves and rotation of the drive ring, and it mainly targets heat exchange systems before the filter, unable to directly clean blockages inside the heat exchanger.

[0006] Offline cleaning focuses on treating contaminants after they have formed. This includes methods such as chemical cleaning, high-pressure water jet cleaning, or ultrasonic cleaning. However, these methods are mostly reactive maintenance and cannot prevent performance degradation. Furthermore, chemical cleaning may corrode equipment, and high-pressure water cleaning and mechanical cleaning usually require downtime, thus failing to achieve true online maintenance.

[0007] Online cleaning focuses on continuously keeping equipment clean and slowing down the formation of dirt. For example, it employs technologies such as mechanical scraping, backwashing, self-cleaning filters, or circulating filtration. These methods are mostly built into the system and automatically triggered, proactively intervening in dirt accumulation during equipment operation and significantly extending equipment maintenance cycles. Summary of the Invention

[0008] The technical problem to be solved by the present invention is: In order to solve the technical problems existing in the prior art, the present invention provides a shell-and-tube heat exchanger that enables reliable condition monitoring and cleaning maintenance of the shell side without interrupting the heat exchanger and the main process flow.

[0009] The technical solution adopted by the present invention to solve its technical problem is: a shell-and-tube heat exchanger, comprising: a heat exchanger body; The liquid inlet switching assembly includes a main inlet pipe and a branch pipe. The main inlet pipe is connected to the middle of the branch pipe. The two ends of the branch pipe are respectively connected to a first filter branch and a second filter branch. The first filter branch and the second filter branch are connected in parallel to the shell-side medium inlet of the heat exchanger body. Both the first filter branch and the second filter branch are equipped with filter boxes and on / off valves. The on / off valves are used to control the on / off of the corresponding filter branch, so that one of the two filter branches is in the working state of conduction and the other is in the standby state of being cut off. A pressure monitoring assembly is disposed outside each of the filter boxes. Each pressure monitoring assembly includes a detection box and a trigger diaphragm disposed between the detection box and the filter box. The trigger diaphragm is used to seal and isolate the inner cavity of the detection box from the inner cavity of the filter box. A pressure sensor is provided inside the detection box. A trigger rod is movably provided inside the detection box. One end of the trigger rod is connected to the trigger diaphragm, and the other end of the trigger rod is operably abutted against the sensing end of the pressure sensor, for transmitting the fluid pressure inside the filter box sensed by the trigger diaphragm to the pressure sensor. A backwashing assembly is disposed inside each of the filter boxes. Each backwashing assembly includes a filter screen, a backwashing unit, and a draining unit. The filter screen is disposed inside the filter box. The backwashing unit is disposed below the filter screen for backwashing the filter screen. The draining unit is disposed above the filter screen for draining the backwashing waste liquid. The first filtering branch and the second filtering branch are configured as follows: When the pressure sensor on any filter branch in operation detects that the pressure has reached a preset value, the on / off valve of that filter branch is closed and the operation is switched to another filter branch; and after the on / off valve is closed, the backwashing unit and the sewage discharge unit of that filter branch are started to perform reverse flushing, and the flushing is stopped after completion, and the filter branch is restored to standby status.

[0010] Furthermore, the pressure monitoring assembly also includes a diaphragm plate and a trigger sleeve. The trigger rod is connected to the trigger diaphragm through the diaphragm plate, the trigger sleeve is installed inside the detection box, the trigger sleeve is sleeved outside the trigger rod, and the pressure sensor is located at the bottom of the trigger sleeve.

[0011] Furthermore, the trigger diaphragm is a metal diaphragm or a rubber diaphragm.

[0012] Furthermore, the backwashing unit includes a backwashing pipe, a backwashing valve, and a self-rotating spray rod. One end of the backwashing pipe is connected to an external cleaning medium supply system, and the other end of the backwashing pipe passes through the side wall of the filter box and is connected to the self-rotating spray rod. The backwashing valve is located on one end of the backwashing pipe, and the self-rotating spray rod is located below the filter screen.

[0013] Furthermore, the sewage discharge unit includes a sewage discharge connector and a sewage discharge plug. The sewage discharge connector is disposed on the outer wall of the filter box and extends radially outward along the filter box. One end of the sewage discharge connector communicates with the interior of the filter box, and the sewage discharge plug is sealed on the other end of the sewage discharge connector. The sewage discharge plug is threadedly connected to the sewage discharge connector.

[0014] Furthermore, the filter box has a dirt collection chamber inside, which is frustum-shaped. The diameter of the dirt collection chamber gradually decreases from the medium inlet of the filter box towards the heat exchanger body. Multiple centripetal spiral guide vanes are arranged around the side wall of the dirt collection chamber, and the centripetal spiral guide vanes are located between the sewage discharge unit and the filter screen.

[0015] Furthermore, the liquid inlet switching assembly also includes a central connector pipe and a central connecting box that are interconnected, as well as a central mounting support plate installed on the central connecting box. The first filtration branch and the second filtration branch are connected in parallel to the central connecting box. The central connector pipe is connected to the shell-side medium inlet of the heat exchanger body. The on / off valve includes an inlet valve and a filter box valve. The first filtration branch and the second filtration branch each include a filter box connecting pipe, a side mounting support plate, a filter box bend, and a connecting pipe. The inlet valve is located at the connection between the diversion pipe and the filter box connecting pipe. The filter box connecting pipe passes through the side mounting support plate and is connected to the medium inlet of the filter box. The side mounting support plate is installed on the central mounting support plate. The filter box valve is located at the connection between the medium outlet of the filter box and the filter box bend. The filter box bend is connected to the central connecting box through the connecting pipe.

[0016] Furthermore, a one-way locking flap is installed at the connection between the filter box bend and the connecting pipe.

[0017] Furthermore, a sedimentation trough recessed outward from the bend of the filter box bend is provided at the bend of the filter box bend. The sedimentation trough is located directly below the medium outlet of the filter box, and a slag discharge valve is provided at the lower end of the sedimentation trough.

[0018] Furthermore, the heat exchanger body includes a heat exchange shell, a first shell-side port, a second shell-side port, a first tube-side port, a second tube-side port, a partition plate, two tube bundle plates, a plurality of first heat exchange tube bundles, a plurality of second heat exchange tube bundles, and multiple baffles. The two tube bundle plates are axially spaced within the heat exchange shell, dividing the interior of the heat exchange shell into a first end water chamber, a middle heat exchange chamber, and a second end water chamber. The partition plate is located within the first end water chamber, dividing it into an upper water chamber and a lower water chamber. The first tube-side port is located on the side wall of the heat exchange shell and communicates with the upper water chamber. The second tube-side port is located on the side wall of the heat exchange shell and communicates with the lower water chamber. The first shell-side port is located on one side wall of the heat exchange shell and close to... Near the first end water chamber, the first filter branch and the second filter branch are connected in parallel to the first shell-side port. The second shell-side port is located on the other side wall of the heat exchange shell and is close to the second end water chamber. Several first heat exchange tube bundles are installed between two tube bundle plates and are used to connect the upper water chamber and the second end water chamber. Several second heat exchange tube bundles are installed between two tube bundle plates and are used to connect the second end water chamber and the lower water chamber. A portion of the baffles are located in the upper half of the middle heat exchange chamber and allow several first heat exchange tube bundles to pass through. Another portion of the baffles are located in the lower half of the middle heat exchange chamber and allow several second heat exchange tube bundles to pass through. The baffles on the first heat exchange tube bundles and the baffles on the second heat exchange tube bundles are alternately arranged.

[0019] The beneficial effects of this invention are: 1. Continuous online switching and backwashing ensure process continuity. This invention uses a parallel first and second filtration branch with on / off valves to selectively activate either branch. When the pressure sensor on the operating filtration branch detects a preset pressure value, the on / off valve automatically closes, switching to the other branch. Simultaneously, the backwashing and drainage units of the disconnected branch are activated for reverse flushing. After flushing, the branch returns to standby mode. Because one filtration branch is always active during the switching-flushing-reset process, maintenance of the filtration unit can be completed without interrupting the heat exchanger body and the entire main process flow.

[0020] 2. This invention features a detection box outside the filter box. The fluid pressure inside the filter box is transmitted to the pressure sensor located inside the detection box via a purely mechanical transmission path through a trigger diaphragm and trigger rod. This physically isolated pressure monitoring completely isolates the pressure sensor from the high-temperature corrosive process medium inside the filter box, fundamentally avoiding signal drift or even failure caused by scaling and corrosion when the sensor is in direct contact with the medium. This enables the pressure sensor to achieve long-term, highly reliable, and stable operation under the high-temperature and highly corrosive shell-side conditions of a chemical plant, providing accurate signal input for automatic switching control.

[0021] 3. This invention features a backwashing unit with a self-rotating multi-hole spray bar located below the filter screen. During backwashing, the spray bar rotates under the reaction force of the jet, achieving comprehensive, blind-spot-free backwashing of the filter screen surface. Simultaneously, as the flushed impurities flow upward with the water flow past the centrifugal guide vanes, the fluid is forcibly modulated into a high-energy centrifugal vortex. Under centrifugal force, solid particles are thrown against the wall of the frustum-shaped collection chamber and rise along the wall in a swirling motion, finally being smoothly discharged from the drain unit located above the filter screen. This avoids disordered splashing of impurities within the chamber during backwashing, the creation of cleaning dead zones, and incomplete discharge.

[0022] 4. The present invention provides a one-way locking flap at the intersection of the filter box bend and the connecting pipe, and provides a downward sludge trough below the bend of the filter box bend. The entire process of flow channel locking and impurity interception-settling-collection is automatically completed at the moment the working branch is switched off, thus avoiding the pollution caused by impurities flowing into the heat exchanger body due to the switching of the branch. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Figure 1 This is a schematic diagram of the structure of a shell-and-tube heat exchanger according to the present invention.

[0025] Figure 2 This is a schematic diagram of the internal structure of the heat exchanger body of the present invention.

[0026] Figure 3 This is a schematic diagram of the liquid inlet switching component of the present invention.

[0027] Figure 4 This is a schematic diagram of the internal structure of any filtering branch of the present invention.

[0028] Figure 5 This is a schematic diagram of the pressure monitoring component of the present invention.

[0029] Figure 6 This is a schematic diagram of the internal structure of the pressure monitoring component of the present invention.

[0030] In the diagram: 00, reactor body; 1. Heat exchanger body; 101. Heat exchange shell; 102. First shell-side port; 103. Second shell-side port; 104. First tube-side port; 105. Second tube-side port; 106. Baffle plate; 107. Tube bundle plate; 108. First heat exchange tube bundle; 109. Second heat exchange tube bundle; 110. Baffle plate; 111. First end water chamber; 1111. Upper water chamber; 1112. Lower water chamber; 112. Middle heat exchange chamber; 113. Second end water chamber; 114. Mounting hole; 2. Liquid inlet switching assembly; 201. Main inlet pipe; 202. Diverter pipe; 203. Central connector pipe; 204. Central connecting box; 205. First filtration branch; 206. Second filtration branch; 207. Filter box; 208. Central mounting plate; 209. Inlet valve; 210. Filter box valve; 211. Filter box connecting pipe; 212. Side mounting plate; 213. Filter box bend; 214. Connecting pipe; 215. Sludge collection chamber; 216. One-way interlocking flap valve; 217. Sludge tank; 218. Sludge discharge valve; 3. Pressure monitoring assembly; 301. Detection box; 302. Trigger diaphragm; 303. Pressure sensor; 304. Trigger rod; 305. Diaphragm plate; 306. Trigger sliding sleeve; 4. Backwash assembly; 401. Filter screen; 402. Backwash pipe; 403. Backwash valve; 404. Self-rotating spray bar; 405. Centripetal spiral guide vane; 406. Drain connector; 407. Drain plug. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0032] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and 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 a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0033] 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 connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] like Figure 1-6 The image shows a preferred embodiment of the present invention, a shell-and-tube heat exchanger, which is disposed inside the reactor body 00. The shell-and-tube heat exchanger includes: a heat exchanger body 1, a liquid inlet switching assembly 2, a pressure monitoring assembly 3, and a backwashing assembly 4.

[0035] The liquid inlet switching assembly 2 includes a main inlet pipe 201, a branch pipe 202, a central connector pipe 203, and a central connecting box 204. The main inlet pipe 201 is connected to the middle of the branch pipe 202. The two ends of the branch pipe 202 are respectively connected to a first filter branch 205 and a second filter branch 206. The first filter branch 205 and the second filter branch 206 are connected in parallel to the central connecting box 204. The central connector pipe 203 is connected to the central connecting box 204. The central connector pipe 203 is connected to the shell-side medium inlet of the heat exchanger body 1. Both the first filter branch 205 and the second filter branch 206 are equipped with a filter box 207 and an on / off valve. The on / off valve is used to control the on / off of the corresponding filter branch, so that one of the two filter branches is in a conducting working state and the other is in a cut-off standby state.

[0036] In a preferred embodiment, a central mounting plate 208 is installed on the central connecting box 204. The on / off valves include an inlet valve 209 and a filter box valve 210. The first filtration branch 205 and the second filtration branch 206 each include a filter box connecting pipe 211, a side mounting plate 212, a filter box bend 213, and a connecting pipe 214. The inlet valve 209 is located at the connection between the diversion pipe 202 and the filter box connecting pipe 211. The filter box connecting pipe 211 passes through the side mounting plate 212 and communicates with the medium inlet of the filter box 207. The side mounting plate 212 is installed on the central mounting plate 208. The filter box valve 210 is located at the connection between the medium outlet of the filter box 207 and the filter box bend 213. The filter box bend 213 communicates with the central connecting box 204 through the connecting pipe 214. Thus, the side mounting plate 212 and the central mounting plate 208 cooperate to provide fixed support for the two filtration branches.

[0037] In a preferred embodiment, the pressure monitoring component 3 is disposed outside each filter box 207. Each pressure monitoring component 3 includes a detection box 301 and a trigger diaphragm 302 disposed between the detection box 301 and the filter box 207. The trigger diaphragm 302 is used to seal and isolate the inner cavity of the detection box 301 from the inner cavity of the filter box 207. A pressure sensor 303 is provided inside the detection box 301. A trigger rod 304 is movably provided inside the detection box 301. One end of the trigger rod 304 is connected to the trigger diaphragm 302, and the other end of the trigger rod 304 is operably abutted against the sensing end of the pressure sensor 303, for transmitting the fluid pressure inside the filter box 207 sensed by the trigger diaphragm 302 to the pressure sensor 303.

[0038] In a preferred embodiment, the backwashing assembly 4 is disposed inside each filter box 207. Each backwashing assembly 4 includes a filter screen 401, a backwashing unit, and a draining unit. The filter screen 401 is disposed inside the filter box 207. The backwashing unit is disposed below the filter screen 401 for backwashing the filter screen 401. The draining unit is disposed above the filter screen 401 for draining the backwashing waste liquid.

[0039] Specifically, the first filter branch 205 and the second filter branch 206 are configured as follows: When the pressure sensor 303 on any filter branch in operation detects that the pressure has reached the preset value, the on / off valve of that filter branch is closed and the operation is switched to another filter branch; and after the on / off valve is closed, the backwashing unit and the sewage discharge unit of that filter branch are started to perform reverse flushing. After the flushing is completed, the backwashing is stopped and the filter branch is restored to standby status.

[0040] More specifically, in use, the shell-and-tube heat exchanger of the present invention allows the shell-side medium to enter through the main inlet pipe 201. At this time, one of the two filtration branches is either in a conducting state or in a closed standby state. For example, the inlet valve 209 and filter box valve 210 on the first filtration branch 205 are open, meaning the first filtration branch 205 is in a conducting state. The inlet valve 209 and filter box valve 210 on the second filtration branch 206 are closed, meaning the second filtration branch 206 is in a closed standby state. In other words, the shell-side medium passes through the branch pipe 202 and the inlet valve 209 on the first filtration branch 205, sequentially entering the filter box connector 211 and the filter box 207. The shell-side medium is filtered by the filter screen 401 inside the filter box 207, and the filtered impurities are placed on the filter screen 401. The filtered shell-side medium then enters the shell-side medium inlet of the heat exchanger body 1 through the filter box valve 210, the filter box bend 213, the connecting pipe 214, the central connecting box 204, and the central connector pipe 203.

[0041] When impurities accumulate to a certain extent on the filter screen 401, the pressure inside the filter box 207 changes. The trigger diaphragm 302, acting as a pressure boundary, deforms under pressure, causing the trigger rod 304 to move and contact the sensing end of the pressure sensor 303. The trigger rod 304 transmits the fluid pressure sensed by the trigger diaphragm 302 inside the filter box 207 to the pressure sensor 303. Subsequently, the inlet valve 209 and filter box valve 210 on the first filtration branch 205 close, while the inlet valve 209 and filter box valve 210 on the second filtration branch 206 open. This means the second filtration branch 206 is in a conducting state, allowing the shell-side medium to enter the second filtration branch 206 through the diversion pipe 202 and then into the shell-side medium inlet of the heat exchanger body 1. Simultaneously, the backwashing unit and drain unit on the first filtration branch 205 activate for backwashing, discharging the impurities accumulated on the filter screen 401 from the drain unit. After washing, the backwashing unit and drain unit stop, and the filtration branch returns to standby mode. Therefore, during the entire process of switching, flushing, and resetting, one of the two filtration branches is always in the conducting state. Thus, the maintenance of the filtration unit can be completed without interrupting the heat exchanger body 1 and the entire main process. Furthermore, the shell-side medium flows from the main inlet pipe 201 to the shell-side medium inlet of the heat exchanger body 1 throughout the entire process, and the flow direction of the shell-side medium is not changed, thus achieving non-stop cleaning of the heat exchanger.

[0042] In a preferred embodiment, the pressure monitoring assembly 3 further includes a diaphragm plate 305 and a trigger sleeve 306. The trigger rod 304 is connected to the trigger diaphragm 302 via the diaphragm plate 305. The diaphragm plate 305 and / or the trigger rod 304 are made of heat-insulating materials (e.g., aerogel composite materials, porous ceramics, etc.). This heat-insulating design allows the pressure sensor 303 to operate in a normal temperature detection environment. The trigger sleeve 306 is installed inside the detection box 301 and is fitted over the trigger rod 304, serving as a guide and improving the movement accuracy of the trigger rod 304. The pressure sensor 303 is located at the bottom of the trigger sleeve 306. This physically isolated pressure monitoring completely isolates the pressure sensor 303 from the high-temperature corrosive process medium inside the filter box 207, fundamentally avoiding signal drift or even failure caused by scaling and corrosion when the sensor is in direct contact with the medium. This enables the pressure sensor 303 to achieve long-term, high-reliability stable operation under the high-temperature and high-corrosion shell-side conditions of a chemical plant.

[0043] In a preferred embodiment, the heat exchanger body 1 includes a heat exchange shell 101, a first shell-side port 102, a second shell-side port 103, a first tube-side port 104, a second tube-side port 105, a partition plate 106, two tube bundle plates 107, a plurality of first heat exchange tube bundles 108, a plurality of second heat exchange tube bundles 109, and a plurality of baffles 110.

[0044] Furthermore, two tube bundle plates 107 are axially spaced within the heat exchange shell 101, dividing the interior of the heat exchange shell 101 into a first end water chamber 111, a middle heat exchange chamber 112, and a second end water chamber 113. The tube bundle plates 107 are used to fix the first heat exchange tube bundle 108 and the second heat exchange tube bundle 109. The tube bundle plates 107 have a plurality of mounting holes 114 arranged on them. The two ends of the first heat exchange tube bundle 108 and the second heat exchange tube bundle 109 pass through these mounting holes 114 and are fixed to the tube bundle plates 107 by expansion or welding, so as to completely isolate the tube-side medium and the shell-side medium and prevent the mixing of two fluids with different temperatures and properties in the end water chamber.

[0045] Furthermore, a partition plate 106 is disposed within the first end water chamber 111, dividing the first end water chamber 111 into an upper water chamber 1111 and a lower water chamber 1112. A first tube-side port 104 is disposed on the side wall of the heat exchange shell 101 and communicates with the upper water chamber 1111. A second tube-side port 105 is disposed on the side wall of the heat exchange shell 101 and communicates with the lower water chamber 1112. The first tube-side port 104 and the second tube-side port 105 are the inlet and outlet channels for the tube-side medium. The tube-side medium (such as cooling water or hot process medium) flows in from one of the tube-side ports (e.g., the first tube-side port 104) and passes through the heat exchange tubes. After being guided by the tube bundle and the partition 106, the fluid flows out from another tube port (e.g., the second tube port 105), completing the circulation of the fluid inside the heat exchange tubes. The partition 106 separates the space of the first end water chamber 111, forcing the tube-side medium to enter the upper water chamber 1111 and then through the first heat exchange tube bundle 108 into the second end water chamber 113. After being deflected by the second heat exchange tube bundle 109, it flows into the lower water chamber 1112, making the heat exchanger configured as a double-tube-pass structure. This increases the flow length and residence time of the tube-side medium inside the heat exchanger, greatly improving the thoroughness of heat exchange.

[0046] Furthermore, the first shell-side port 102 is located on one side wall of the heat exchange shell 101 and close to the first end water chamber 111. The first filter branch 205 and the second filter branch 206 are connected in parallel to the first shell-side port 102. The second shell-side port 103 is located on the other side wall of the heat exchange shell 101 and close to the second end water chamber 113. The first shell-side port 102 and the second shell-side port 103 are the inlet and outlet channels for the shell-side medium. The shell-side medium filtered by the first filter branch 205 or the second filter branch 206 enters the middle heat exchange chamber 112 through the first shell-side port 102. The shell-side medium flows between the outer wall of the heat exchange tube bundle and the heat exchange shell 101. After exchanging heat with the tube-side medium in the heat exchange tube bundle, it flows out from the second shell-side port 103.

[0047] Furthermore, several first heat exchange tube bundles 108 are installed between two tube bundle plates 107 and are used to connect the upper water chamber 1111 and the second end water chamber 113. Several second heat exchange tube bundles 109 are installed between two tube bundle plates 107 and are used to connect the second end water chamber 113 and the lower water chamber 1112. A portion of baffles 110 are disposed in the upper half of the middle heat exchange chamber 112 and allow several first heat exchange tube bundles 108 to pass through. Another portion of baffles 110 are disposed in the lower half of the middle heat exchange chamber 112 and allow several second heat exchange tube bundles 109 to pass through. The baffles 110 on the first heat exchange tube bundles 108 and the baffles 110 on the second heat exchange tube bundles 109 are alternately arranged at intervals. The baffles 110 prevent the heat exchange tube bundle from bending, sagging, or even vibrating violently due to its own weight, thermal stress, or fluid impact caused by excessive tube length, thus providing rigid support. Furthermore, the baffles 110 are arranged alternately at intervals, so the shell-side medium cannot flow in a straight line under the staggered obstruction and guidance of the baffles 110, but is forced to flow in a serpentine bend. During this process, the shell-side medium repeatedly scours and sweeps across the outer walls of the first heat exchange tube bundle 108 and the second heat exchange tube bundle 109, achieving full and efficient heat exchange with the tube-side medium of the heat exchange tube bundle.

[0048] In other words, in the heat exchanger body 1, the tube-side medium and the shell-side medium are two completely independent and unmixed flow systems, and their flow processes in the heat exchanger body 1 are as follows: The tube-side medium flows into the upper water chamber 1111 from the first tube-side port 104, enters the second end water chamber 113 through the first heat exchange tube bundle 108, then flows back through the second heat exchange tube bundle 109 and flows into the lower water chamber 1112, and finally flows out from the second tube-side port 105. After being filtered by the first filtration branch 205 or the second filtration branch 206, the shell-side medium enters the middle heat exchange chamber 112 through the first shell-side port 102. After passing through multiple deflections between the outer wall of the heat exchange tube bundle and the heat exchange shell 101, the shell-side medium flows to the other end of the middle heat exchange chamber 112 and flows out from the second shell-side port 103 to the subsequent process system (such as to the subsequent chemical reaction system or storage tank).

[0049] In a preferred embodiment, the backwashing unit includes a backwash pipe 402, a backwash valve 403, and a self-rotating spray bar 404. One end of the backwash pipe 402 is connected to an external cleaning medium supply system, and the other end of the backwash pipe 402 passes through the side wall of the filter box 207 and is connected to the self-rotating spray bar 404. The backwash valve 403 is located on one end of the backwash pipe 402, and the self-rotating spray bar 404 is located below the filter screen 401. During backwashing, the backwash valve 403 opens, and the cleaning medium is injected from the backwash pipe 402 and sprayed out from the porous self-rotating spray bar 404 at its end. Due to the reaction force of the spray, the self-rotating spray bar 404 rotates below the filter screen 401, forming a moving linear high-pressure water column, which performs all-round, blind-spot-free reverse flushing and stripping of impurities on the filter screen 401.

[0050] In a preferred embodiment, the filter box 207 has a dirt collection chamber 215 inside. The dirt collection chamber 215 is frustoconical in shape, and its diameter gradually decreases from the medium inlet of the filter box 207 towards the heat exchanger body 1. Multiple centripetal spiral guide vanes 405 are arranged around the side wall of the dirt collection chamber 215, located between the drain unit and the filter screen 401. During backwashing, the dirty liquid carrying impurities peels off the filter screen 401, flows upward, and impacts the centripetal spiral guide vanes 405. The vanes convert the vertical upward kinetic energy of the dirty liquid into an initial rotational tangential velocity, causing the dirty liquid and the solid particles it carries to be thrown towards the inner wall of the dirt collection chamber 215 under inertia, forming a centrifugal vortex that rotates along the wall. As the wastewater flows upward along the frustum-shaped collection chamber 215, its radius of rotation gradually increases. The upwardly expanding profile of the wall provides a gradually smoothing outward force to the solid particles rotating against the wall. This outward force significantly reduces the normal pressure and frictional resistance of the particles against the wall, allowing the impurity particles to maintain a high tangential velocity and smoothly slide upward under conditions of extremely low wall frictional resistance. During this process, although the diameter of the collection chamber 215 gradually increases from bottom to top, which slows down the axial flow velocity, the tangential kinetic energy of the particles adhering to the wall is effectively maintained. They still have sufficient kinetic energy until they reach the discharge unit located above the collection chamber 215, and are finally discharged accurately and smoothly under the action of centrifugal force. This completely overcomes the defect of conventional cylindrical collection chambers 215 where the tangential kinetic energy of the particles rapidly decays due to wall frictional resistance, preventing them from reaching the discharge port.

[0051] In a preferred embodiment, the drain unit includes a drain connector 406 and a drain plug 407. The drain connector 406 is disposed on the outer wall of the filter box 207 and extends radially outward along the filter box 207. One end of the drain connector 406 communicates with the interior of the filter box 207, and the drain plug 407 is sealed to the other end of the drain connector 406. The drain plug 407 is threadedly connected to the drain connector 406. During backwashing, the drain plug 407 can be removed from the drain connector 406 to allow the wastewater carrying impurities to be discharged from the drain connector 406.

[0052] In another preferred embodiment, in order to improve the automation of sewage discharge, the sewage discharge unit includes a sewage discharge connector 406 and a sewage discharge valve (not shown in the figure). The sewage discharge valve is provided on the sewage discharge connector 406. When backwashing is performed, the sewage discharge valve is opened to allow sewage to be discharged.

[0053] After backwashing is completed, the drain valve is closed or the drain plug 407 re-seals the drain connector 406, the backwash valve 403 is closed, and the delivery of cleaning medium into the filter box 207 is stopped.

[0054] In a preferred embodiment, a control module (not shown in the figure) is provided on the reactor body 00. The control module is connected to the pressure sensor 303 on the two filter branches and is also connected to the inlet valve 209, filter box valve 210, drain valve and backwash valve 403 for control.

[0055] In a preferred embodiment, a one-way locking flap 216 is provided at the connection between the filter box bend 213 and the connecting pipe 214.

[0056] In a preferred embodiment, a sedimentation trough 217 recessed outward from the bend of the filter box bend 213 is provided at the bend of the filter box bend 213. The sedimentation trough 217 is directly below the medium outlet of the filter box 207, and a slag discharge valve 218 is provided at the lower end of the sedimentation trough 217.

[0057] Specifically, when the pressure sensor 303 on a certain filtration branch detects excessive pressure, and the control module controls the inlet switching component 2 to switch the path (for example, from the first filtration branch 205 to the second filtration branch 206), the inlet valve 209 and the filter box valve 210 of the first filtration branch 205 close. At this instant of closure, the flow rate of the shell-side medium in the first filtration branch 205 instantly drops to zero. Unconsolidated impurities that were originally adsorbed on the lower surface of the filter screen 401 or suspended in the filter box bend 213 begin to fall due to gravity. At this time, the one-way locking flap 216 loses the forward thrust of the fluid and, under its own weight and the weak back pressure of the return water, instantly and automatically flips downward and closes, completely locking the flow channels leading to the connecting pipe 214, the central connecting box 204, the central connector pipe 203, and the heat exchanger body 1. The falling solid impurities and dirt, blocked and guided by the one-way locking flap 216, accurately fall into the sedimentation tank 217 at the bend of the filter box bend 213. While the system continues to operate without stopping, the slag discharge valve 218 at the bottom of the slag tank 217 can be opened periodically to discharge these potential impurities, thus completely avoiding secondary pollution inside the heat exchanger body 1 caused by frequent switching of branches.

[0058] Example 2: The difference from Example 1 is that the trigger diaphragm 302 is a metal diaphragm, which can achieve reliable operation under high pressure, high temperature and long cycle.

[0059] Example 3: The difference from Example 1 is that the trigger diaphragm 302 is a rubber diaphragm. Rubber diaphragms are more suitable for low-pressure, non-demanding working conditions that require large deformation or are cost-sensitive, and can meet the usage requirements.

[0060] It should be noted that this invention is a shell-and-tube heat exchanger, and all components are general standard parts or parts known to those skilled in the art. Its structure and principle can be learned by those skilled in the art through technical manuals or conventional experimental methods. In the idle part of this device, all the above-mentioned electrical components, which refer to power elements, electrical components, and the matching monitoring computer and power supply, are connected by wires. The specific connection method should refer to the working principle above and complete the electrical connection in the order of operation between each electrical component. The detailed connection method is a well-known technology in the field.

[0061] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A shell-and-tube heat exchanger, characterized in that, include: Heat exchanger body (1); Liquid inlet switching assembly (2), the liquid inlet switching assembly (2) includes a main inlet pipe (201) and a branch pipe (202). The main inlet pipe (201) is connected to the middle of the branch pipe (202). The two ends of the branch pipe (202) are respectively connected to a first filter branch (205) and a second filter branch (206). The first filter branch (205) and the second filter branch (206) are connected in parallel to the shell-side medium inlet of the heat exchanger body (1). The first filter branch (205) and the second filter branch (206) are each provided with a filter box (207) and an on / off valve. The on / off valve is used to control the on / off of the corresponding filter branch, so that one of the two filter branches is in the working state of conduction and the other is in the standby state of cut-off. A pressure monitoring component (3) is disposed outside each of the filter boxes (207). Each pressure monitoring component (3) includes a detection box (301) and a trigger diaphragm (302) disposed between the detection box (301) and the filter box (207). The trigger diaphragm (302) is used to seal and isolate the inner cavity of the detection box (301) from the inner cavity of the filter box (207). A pressure sensor (303) is provided inside the detection box (301). A trigger rod (304) is movably provided inside the detection box (301). One end of the trigger rod (304) is connected to the trigger diaphragm (302), and the other end of the trigger rod (304) is operably abutted against the sensing end of the pressure sensor (303) to transmit the fluid pressure in the filter box (207) sensed by the trigger diaphragm (302) to the pressure sensor (303). A backwashing assembly (4) is disposed inside each of the filter boxes (207). Each backwashing assembly (4) includes a filter screen (401), a backwashing unit, and a draining unit. The filter screen (401) is disposed inside the filter box (207). The backwashing unit is disposed below the filter screen (401) and is used to backwash the filter screen (401). The draining unit is disposed above the filter screen (401) and is used to discharge the backwashing waste liquid. The first filtering branch (205) and the second filtering branch (206) are configured as follows: When the pressure sensor (303) on any filter branch in operation detects that the pressure has reached a preset value, the on / off valve of that filter branch is closed and switched to another filter branch for operation; and after the on / off valve is closed, the backwashing unit and the sewage discharge unit of that filter branch are started for backwashing, and the backwashing is stopped after it is completed, and the filter branch is restored to standby status.

2. A shell-and-tube heat exchanger according to claim 1, characterized in that, The pressure monitoring assembly (3) also includes a diaphragm plate (305) and a trigger sleeve (306). The trigger rod (304) is connected to the trigger diaphragm (302) through the diaphragm plate (305). The trigger sleeve (306) is installed inside the detection box (301) and is sleeved on the outside of the trigger rod (304). The pressure sensor (303) is located at the bottom of the trigger sleeve (306).

3. A shell-and-tube heat exchanger according to claim 1, characterized in that, The trigger diaphragm (302) is a metal diaphragm or a rubber diaphragm.

4. A shell-and-tube heat exchanger according to claim 1, characterized in that, The backwashing unit includes a backwash pipe (402), a backwash valve (403), and a self-rotating spray rod (404). One end of the backwash pipe (402) is connected to an external cleaning medium supply system, and the other end of the backwash pipe (402) passes through the side wall of the filter box (207) and is connected to the self-rotating spray rod (404). The backwash valve (403) is located on one end of the backwash pipe (402), and the self-rotating spray rod (404) is located below the filter screen (401).

5. A shell-and-tube heat exchanger according to claim 1, characterized in that, The sewage discharge unit includes a sewage discharge connector (406) and a sewage discharge plug (407). The sewage discharge connector (406) is disposed on the outer wall of the filter box (207) and extends radially outward along the filter box (207). One end of the sewage discharge connector (406) communicates with the interior of the filter box (207). The sewage discharge plug (407) is sealed on the other end of the sewage discharge connector (406). The sewage discharge plug (407) is threadedly connected to the sewage discharge connector (406).

6. A shell-and-tube heat exchanger according to claim 1, characterized in that, The filter box (207) has a dirt collection chamber (215) inside. The dirt collection chamber (215) is frustum-shaped. The diameter of the dirt collection chamber (215) gradually decreases from the medium inlet of the filter box (207) towards the heat exchanger body (1). Multiple centripetal spiral guide vanes (405) are arranged around the side wall of the dirt collection chamber (215). The centripetal spiral guide vanes (405) are located between the sewage discharge unit and the filter screen (401).

7. A shell-and-tube heat exchanger according to claim 1, characterized in that, The liquid inlet switching assembly (2) also includes a central connector pipe (203) and a central connecting box (204) that are interconnected, and a central mounting support plate (208) installed on the central connecting box (204). The first filtration branch (205) and the second filtration branch (206) are connected in parallel to the central connecting box (204). The central connector pipe (203) is connected to the shell-side medium inlet of the heat exchanger body (1). The on / off valve includes an inlet valve (209) and a filter box valve (210). The first filtration branch (205) and the second filtration branch (206) each include a filter box connecting pipe (211). The filter box consists of a side mounting plate (212), a filter box bend (213), and a connecting pipe (214). An inlet valve (209) is located at the connection between the diversion pipe (202) and the filter box connector (211). The filter box connector (211) passes through the side mounting plate (212) and is connected to the medium inlet of the filter box (207). The side mounting plate (212) is mounted on the central mounting plate (208). The filter box valve (210) is located at the connection between the medium outlet of the filter box (207) and the filter box bend (213). The filter box bend (213) is connected to the central connecting box (204) through the connecting pipe (214).

8. A shell-and-tube heat exchanger according to claim 7, characterized in that, A one-way locking flap (216) is provided at the connection between the filter box bend (213) and the connecting pipe (214).

9. A shell-and-tube heat exchanger according to claim 7, characterized in that, A sedimentation trough (217) recessed outward from the bend of the filter box bend (213) is provided at the bend of the filter box bend (213). The sedimentation trough (217) is located directly below the medium outlet of the filter box (207). A slag discharge valve (218) is provided at the lower end of the sedimentation trough (217).

10. A shell-and-tube heat exchanger according to claim 1, characterized in that, The heat exchanger body (1) includes a heat exchange shell (101), a first shell-side port (102), a second shell-side port (103), a first tube-side port (104), a second tube-side port (105), a partition plate (106), two tube bundle plates (107), a plurality of first heat exchange tube bundles (108), a plurality of second heat exchange tube bundles (109), and a plurality of baffles (110). The two tube bundle plates (107) are axially spaced within the heat exchange shell (101) and divide the interior of the heat exchange shell (101) into a first end water chamber (111). The heat exchange chamber consists of a central heat exchange chamber (112) and a second end water chamber (113). A partition plate (106) is disposed in the first end water chamber (111) and divides the first end water chamber (111) into an upper water chamber (1111) and a lower water chamber (1112). A first tube-side port (104) is disposed on the side wall of the heat exchange shell (101) and communicates with the upper water chamber (1111). A second tube-side port (105) is disposed on the side wall of the heat exchange shell (101) and communicates with the lower water chamber (1112). A first shell-side port (102) is disposed on the side wall of the heat exchange shell (101). On one side wall of the heat exchange shell (101) and near the first end water chamber (111), the first filter branch (205) and the second filter branch (206) are connected in parallel to the first shell-side port (102). The second shell-side port (103) is located on the other side wall of the heat exchange shell (101) and near the second end water chamber (113). Several first heat exchange tube bundles (108) are installed between two tube bundle plates (107) and are used to connect the upper water chamber (1111) and the second end water chamber (113). Several second heat exchange tube bundles (109) are installed on the two tube bundle plates. (107) is used to connect the second end water chamber (113) and the lower water chamber (1112). A portion of the baffles (110) is located in the upper half of the middle heat exchange chamber (112) and allows several first heat exchange tube bundles (108) to pass through. Another portion of the baffles (110) is located in the lower half of the middle heat exchange chamber (112) and allows several second heat exchange tube bundles (109) to pass through. The baffles (110) on the first heat exchange tube bundle (108) and the baffles (110) on the second heat exchange tube bundle (109) are alternately arranged at intervals.

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