Coupled finned tube gas vacuum phase change hot water boiler

Abstract

This invention discloses a coupled finned tube gas-fired vacuum phase change hot water boiler, which adopts a horizontal arrangement. The burner outlet is connected to the sealed furnace space. The membrane water-cooled wall evaporative heat exchange tube bundle is located before and after the sealed furnace space, and the coupled finned tube evaporative heat exchange tube bundle is located on both sides of the sealed furnace space. The upper steam-water chamber and the lower water chamber are located above and below the sealed furnace space, respectively. The coupled finned tube flue gas condenser heat exchange tube bundle and the chimney are arranged along the flue gas flow direction at the rear of the furnace. The coupled finned tube evaporative heat exchange tube bundle and the coupled finned tube flue gas condenser heat exchange tube bundle adopt slit heat exchange tube bundle. The slit microchannel laminar flow enhances heat transfer, significantly improving the heat transfer coefficient. It achieves compact structure, simplified process, short flow, and low resistance enhanced heat transfer, which not only reduces carbon emissions from raw materials and manufacturing processes, but more importantly, directly reduces operating carbon emissions and operating costs caused by power consumption, truly achieving the lowest carbon emissions throughout the product supply chain.

Description

Technical Field

[0001] This invention belongs to the field of gas-fired boiler technology, specifically relating to a coupled finned tube gas-fired vacuum phase change hot water boiler. Background Technology

[0002] Currently, there are many types of gas-fired hot water boilers on the market. In particular, gas-fired vacuum phase change hot water boilers are favored by heating users due to their unique features such as negative pressure operation, large safety margin, no scale buildup on high-temperature heating surfaces, and enhanced heat transfer through condensation phase change. However, existing gas-fired vacuum phase change hot water boilers only use traditional flue gas turbulence-enhanced heat transfer, which has weak enhancement capacity, long flue gas scouring process, and high flue gas flow resistance. This leads to increased fan power and significantly increased operating power consumption, thereby increasing carbon emissions and operating costs. This is a type of carbon emission that increases with the extension of product operating time. Secondly, due to the weak flue gas enhanced heat transfer capacity, the boiler requires a large heating surface, resulting in a large volume and high raw material consumption. Thirdly, the turbulence-enhanced heat transfer tube bundles are numerous, resulting in a large amount of welding work and high process carbon emissions. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a coupled finned tube gas-fired vacuum phase change hot water boiler, which employs slit microchannel laminar flow to enhance heat transfer, significantly improving the heat transfer coefficient. This results in a compact structure, simplified process, short flow path, and low resistance enhanced heat transfer, reducing not only carbon emissions from raw materials and manufacturing processes, but more importantly, directly reducing operating carbon emissions and operating costs caused by power consumption, truly achieving the lowest carbon emissions across the entire product supply chain.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a coupled finned tube gas-fired vacuum phase change hot water boiler, arranged horizontally, includes a burner, a membrane water-cooled wall evaporative heat exchange tube bundle, a coupled finned tube evaporative heat exchange tube bundle, a coupled finned tube flue gas condenser heat exchange tube bundle, an upper steam-water chamber, a lower water chamber, and a chimney; the burner outlet is connected to the sealed furnace space, the membrane water-cooled wall evaporative heat exchange tube bundle is located before and after the sealed furnace space, and the coupled finned tube evaporative heat exchange tube bundle is located within the sealed furnace space. On both sides, the upper steam-water chamber and the lower water chamber are located above and below the sealed space of the furnace, respectively; the coupled finned tube flue gas condenser heat exchange tube bundle and the chimney are arranged behind the furnace along the flue gas flow direction; the coupled finned tube evaporator heat exchange tube bundle and the coupled finned tube flue gas condenser heat exchange tube bundle adopt slit heat exchange tube bundle; the slit heat exchange tube bundle includes base tube and fins, the fins are fixedly connected to the base tube to form heat exchange tubes, several heat exchange tubes are arranged in the same direction, there is a slit channel between two adjacent heat exchange tubes, and there is a slit channel between the fins and their adjacent base tubes.

[0005] The upper and lower ends of the coupled finned tube flue gas condenser heat exchange tube bundle are connected to the upper header and lower header of the flue gas condensation section, respectively. The upper header of the flue gas condensation section is connected in sequence to the inlet header, the steam condensation heat exchange tube bundle and the outlet header; a vacuum pump is installed at the top of the upper steam-water chamber.

[0006] A 1-2mm metal sheet is provided between the two ends of two adjacent heat exchange tubes. The metal sheet is flush with the end face of the heat exchange tube and the fin length is less than the heat exchange tube length. The metal sheet is used to form a gap channel between the tubes. The base tube adopts the material specified in the standard for gas boilers, and the thermal conductivity of the material used for the fins is not less than 200W / (m·K).

[0007] A rectangular base tube and fins with turbulence-inducing columns are welded to form a P-shaped finned tube. The coupled finned tube evaporator heat exchange tube bundle adopts P-shaped finned tubes, and the fins with turbulence-inducing columns adopt two shapes: "J" and "I". The P-shaped finned tubes are arranged in the same direction, and a 1-4 mm wide gap channel is formed between the P-shaped finned tube and the base tube of the adjacent P-shaped finned tube. The coupled finned tube flue gas condenser heat exchange tube bundle adopts P-shaped finned tubes with "I" shaped fins.

[0008] The P-shaped finned tube is formed by bending flat steel three times to form an "I" shaped fin, and by bending it four times to form a "J" shaped fin.

[0009] Coupled finned tube evaporator heat exchanger tube bundle using P-shaped finned tubes + double P mirror image "The finned tube combination allows the flue gas to undergo three heat exchanges in the slit channel, resulting in a three-pass flue gas flow and a double-P mirror image." "The finned tube consists of a base rectangular tube and two fins with turbulence-inducing columns; double P mirror image." "Shaped finned tube and adjacent double P mirror image" A 1-4 mm wide slit channel is formed between the base tubes of the finned tube.

[0010] The coupled finned tube evaporator heat exchanger tube bundle uses P-shaped finned tubes + W-shaped finned tubes. The W-shaped finned tube includes a base tube rectangular tube, a fin with a turbulence column and a smooth straight fin. The fin with the turbulence column and the smooth straight fin are respectively set on two opposite edges of the base tube rectangular tube.

[0011] The P-shaped finned tube is positioned using a welding bed during welding; the width of the welding bed is 2-4 mm wider than the base tube, and there are protrusions on the welding bed to support the base tube. There are movable pressure plates on both sides of the welding bed to fix the fins. It is mass-produced using narrow-gap submerged arc automatic welding.

[0012] The base tube and the tile fins are welded to form a tile fin Q-shaped finned tube. The coupled finned tube evaporation heat exchange tube bundle adopts a tile fin Q-shaped finned tube. The tile fins are welded to the arc top or side of the base tube and partially surround the adjacent base tube. The base tube adopts a long oval tube or a waist-shaped tube.

[0013] The heat exchange tube bundle of the coupled finned tube flue gas condenser adopts tile-finned Q-shaped finned tubes.

[0014] The coupled finned tube evaporator heat exchanger tube bundles are arranged in parallel or trapezoidal configurations. When the heat exchanger tube bundles are arranged in a trapezoidal configuration, the coupled finned tube evaporator heat exchanger tube bundles use P-shaped finned tubes with "I" shaped fins or Q-shaped finned tubes with tile fins.

[0015] The base tube and fins are welded using narrow-gap submerged arc welding, TIG welding, MIG welding or laser welding processes, with a single-sided V-shaped bevel and full penetration.

[0016] The burners are selected from pre-premixed or post-premixed fully premixed metal fiber surface burners, diffusion burners, or post-premixed fully premixed water-cooled burners.

[0017] When the burner is a diffusion burner, several heat exchange tubes at the front end of the coupled finned tube evaporator heat exchange tube bundle are welded and sealed.

[0018] The burner is a fully premixed water-cooled burner. A round-to-square structure is set on the furnace shell to connect the fully premixed water-cooled burner and the furnace shell. The membrane water-cooled wall evaporation heat exchange tube bundle at the front end of the furnace is arranged in a V-shape or U-shape to form a V-shaped or U-shaped water-cooled combustion surface. Gaps are left between the tube bundles. The premixed gas is distributed to the entire V-shaped or U-shaped combustion surface through the round-to-square structure and then passes through the gaps between the tube bundles to ignite and burn.

[0019] The tube bank extends to the rear membrane water-cooled wall evaporative heat exchange tube bundle, making the boiler a dual-furnace type.

[0020] When using fully premixed water-cooled burners, two or four burners are used. When using two fully premixed water-cooled burners, the flue gas condenser heat exchange tube bundles are arranged on both sides of the boiler, and the burners are arranged in opposite directions. The flue gas enters the furnace from both the front and rear sides at the same time. The high-temperature flue gas formed after combustion undergoes laminar flow enhanced heat exchange along the gap channels of the coupled finned tube evaporator heat exchange tube bundles. After the flue gas turns 90° and flows out, it moves forward and then turns 90° to the outside of the boiler before scouring the flue gas condenser heat exchange tube bundles to continue cooling. After that, it is collected through the square-to-round flue shell and discharged into the atmosphere through the chimney.

[0021] The steam condensation heat exchange tube bundle adopts circular bare tubes and is arranged in a staggered manner. The bottom two or three rows of tube bundles are welded with V-shaped or U-shaped liquid guiding fins.

[0022] The steam condensation heat exchange tube bundle adopts an upper staggered arrangement, and the lower steam condensation heat exchange tube bundle is divided into several parts. Each part is separated by a set area where no steam condensation heat exchange tube bundle is arranged, and the number of steam condensation heat exchange tube bundles in each part gradually decreases from top to bottom.

[0023] A non-vacuum hot water boiler, based on the coupled finned tube gas-fired vacuum phase change hot water boiler of the present invention, wherein the two ends of the membrane water-cooled wall evaporator heat exchange tube bundle, the coupled finned tube evaporator heat exchange tube bundle, and the coupled finned tube flue gas condenser heat exchange tube bundle are directly connected to the upper header and the lower header, and vertical baffles are provided in the upper header and the lower header. A return water inlet is provided at the rear of the upper header, and the return water enters from the return water inlet above the upper header. A return water outlet is provided at the front of the upper header, and the water flows back under the constraint of the baffles in the upper header and the lower header before leaving the boiler.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] This invention discloses a coupled finned tube gas-fired vacuum phase change hot water boiler that employs the concept of laminar flow enhanced heat transfer. By eliminating the central high-temperature zone in the flue gas heat exchange process through slit channels, the boiler flue gas only needs a 40mm to 100mm flow path to reduce its temperature from above 1100℃ to below 300℃. Simultaneously, the flue gas resistance can be controlled below 1000Pa, reducing the boiler's steam consumption per ton of steel and water volume. This invention also utilizes slit microchannel laminar flow enhanced heat transfer, significantly improving the heat transfer coefficient. This results in a compact structure, simplified process, short flow path, and low-resistance enhanced heat transfer, reducing not only carbon emissions from raw materials and manufacturing processes but, more importantly, directly reducing operating carbon emissions and operating costs caused by power consumption, truly achieving the lowest possible carbon emissions across the entire product supply chain. Furthermore, the boiler's furnace wall is constructed of water-cooled walls, which not only reduces cost but also eliminates the risk of collapse and damage caused by excessively high furnace wall temperatures due to high-temperature flue gas in traditional atmospheric pressure boilers.

[0026] Furthermore, the core heat exchange element of the coupled finned tube gas-fired vacuum phase change hot water boiler of the present invention is a P-shaped finned tube and a double P mirror " The finned tube has a simple structure and can be used in boilers of various capacities from 0.1t to 20t. It is easy to process, produce and assemble on a large scale.

[0027] Furthermore, the coupled finned tube gas-fired vacuum phase change hot water boiler of the present invention adopts a centrally symmetrical design and applies an isobaric flue gas channel, so that the flue gas in the furnace can be evenly distributed to each gap channel, solving the problem of uneven flue gas distribution and poor local heat exchange effect in traditional membrane wall vacuum hot water boilers. Attached Figure Description

[0028] The invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0029] Figure 1a This is a front sectional view of a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler. Figure 1bThis is a top view of the furnace body of a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler; Figure 1c This is the top right view of a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler; Figure 1d This is a schematic diagram of the flue gas condensation section heating return water flow in a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler. Figure 1e This is a left view of the front rectangular cross-section tubular membrane water-cooled wall evaporator tube bundle.

[0030] Figure 2a This is a partial cross-sectional schematic diagram of a tube array consisting of P-shaped finned tubes 19 with "J"-shaped fins; Figure 2b This is a partial cross-sectional schematic diagram of a tube array consisting of P-shaped finned tubes 19 with an "I"-shaped fin. Figure 2c This is a partial cross-sectional schematic diagram of a tube bank formed when 20 fins of a tile-shaped Q-shaped finned tube are welded to the side. Figure 2d This is a partial cross-sectional schematic diagram of a tube bank formed by welding 20 fins of a tile-shaped Q-shaped finned tube to the top of an arc.

[0031] Figure 3a This is a schematic diagram of a welding bed used to assist welding in the production of a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler according to the present invention. Figure 3b This is a schematic diagram of the process flow for forming P-shaped finned tubes using a bending machine.

[0032] Figure 4a This is a front left view of part of the pipe bank; Figure 4b This is a rear view of part of the pipe bank.

[0033] Figure 5a It is a schematic diagram of a straight fin with cylindrical spoilers; Figure 5b It is a schematic diagram of a straight fin with square spoilers; Figure 5c This is a schematic diagram of a straight fin with triangular spoiler columns.

[0034] Figure 6 This is a top view of the furnace body of a coupled finned tube gas-fired vacuum phase change hot water boiler using a diffusion burner.

[0035] Figure 7a This is a top view of the furnace body when the front tube bundle is arranged in a V-shape with a fully premixed water-cooled burner in a single furnace of a coupled finned tube gas-fired vacuum phase change hot water boiler. Figure 7b This is a top view of the furnace body when the front tube bundle is arranged in a V-shape with a fully premixed water-cooled burner in a double-furnace structure of a rectangular cross-section coupled finned tube gas vacuum phase change hot water boiler. Figure 7c This is a top view of the furnace body when a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler with a fully premixed water-cooled burner in a single furnace has a U-shaped tube bundle arrangement at the front. Figure 7d This is a top view of the furnace body when the front tube bundle of a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler with a fully premixed water-cooled burner is arranged in a U-shape.

[0036] Figure 8a This is a top view of the boiler body when two fully premixed water-cooled burners are used; Figure 8b This is the upper right view of a boiler using two fully premixed water-cooled burners; Figure 8c This is a front cross-sectional view of a boiler using two fully premixed water-cooled burners; Figure 8d This is a top view of the boiler body when four fully premixed water-cooled burners are used.

[0037] Figure 9a It is a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler using a double-P mirror image. A schematic diagram of the three-pass tube layout for finned tube 25 or W-shaped finned tube 26; Figure 9b It is a dual-P mirror image. Partial cross-sectional view of a tube bank consisting of 25 shaped finned tubes; Figure 9c This is a partial cross-sectional schematic diagram of a tube bank composed of W-shaped finned tubes 26.

[0038] Figure 10a This is a schematic diagram of a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler using a trapezoidal tube layout; Figure 10b This is a partial cross-sectional view of the pipe bank formed when the pipe bank is arranged in a trapezoidal shape and the Q-shaped finned tubes with 20 fins welded to the side are used. Figure 10c This is a partial cross-sectional view of the pipe bank formed when the pipe bank is arranged in a trapezoidal shape and the Q-shaped finned tubes with 20 fins welded to the top of the arc.

[0039] Figure 11a This is a schematic diagram of the overall optical tube with welded V-shaped liquid guiding fins 101; Figure 11b This is a schematic diagram of the overall optical tube with welded U-shaped liquid guiding fins 102.

[0040] Figure 12 This is a schematic diagram of the steam condensation heat exchanger tube bundle 10 with an upper staggered arrangement and a lower M-shaped arrangement.

[0041] Figure 13 This is a front sectional view of a non-vacuum hot water boiler when a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler structure is applied.

[0042] In the attached diagram, 1-blower, 2-burner, 22-burner head, 3-film water-cooled wall evaporative heat exchange tube bundle, 31-furnace front-end film water-cooled wall evaporative heat exchange tube bundle, 4-coupled finned tube evaporative heat exchange tube bundle, 5-coupled finned tube flue gas condenser heat exchange tube bundle, 6-upper steam-water chamber, 7-lower water chamber, 8-inlet header, 9-outlet header, 10-steam condensation heat exchange tube bundle, 101-V-shaped liquid guiding fins, 102-U-shaped liquid guiding fins, 11-upper header of flue gas condensation section, 12-lower header of flue gas condensation section, 13-vacuum pump, 14-boiler body shell plate, 141-left side boiler body shell plate, 142-right side boiler body shell plate. 143-Square to round flue shell, 144-Front connecting plate, 145-Isobaric flue gas passage cover, 15-Insulation material, 16-Color steel plate, 17-Condensate drain hole, 18-Chimney, 19-P-shaped finned tube, 191-Base tube rectangular tube, 192-Fin with turbulence column, 193-Smooth straight fin, 20-Tile fin Q-shaped finned tube, 201-Base tube oblong tube, 202-Tile fin, 23-Welding bed, 231-Pressure plate, 232-Protrusion, 24-Round to square structure, 32-Rear end membrane water-cooled wall evaporator heat exchanger tube bundle, 41-Left evaporator heat exchanger tube bundle, 42-Right evaporator heat exchanger tube bundle, 25-Double P mirror image 26-W-shaped finned tube, 27-Upper header, 28-Lower header, 29-Felt tube. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] The purpose of this invention is to provide a slotted symmetrical membrane wall gas-fired vacuum phase change hot water boiler, proposing an integrated heat transfer element that organically combines the radiative heating surface of a traditional membrane water-cooled wall and the convective heating surface of a traditional water tube bundle into a "radiation-convection integrated" whole heat transfer element, or a novel heat transfer "chip," namely a P-shaped finned tube and a double P mirror "chip." The heat-receiving surface of the tubes uses rectangular cross-section base tubes with "J"-shaped or "I"-shaped fins. The fire-facing surfaces of the fins are etched or forged with various shapes of tiny bosses to create microchannel gaps for enhanced heat transfer, significantly improving the flue gas convection heat transfer coefficient, reducing steel consumption, shrinking boiler size, decreasing flue gas flow resistance, and lowering costs. (Double P mirror image) The gap channels formed between the finned tubes or P-shaped finned tubes can eliminate the central high-temperature zone in the traditional heat exchange process. When the flue gas passes through the gap channels, the entire channel is in the boundary layer region with strong heat and mass transfer, and the heat transfer coefficient can reach 120 W / (m²). 2 ·℃ or above; adopting an axisymmetric design, the flue gas uniformly passes through the gaps between the P-shaped finned tubes into the isobaric flue gas channel, and then passes through the double P mirror " The "J"-shaped fins in this invention refer to fins that have a bend at the connection end with the base tube. This ensures that all tube bundles within the same cycle have the same heat load and that the flue gas resistance is less than 1000 Pa. The "J"-shaped fins in this invention refer to fins that have a bend at the connection end with the base tube. Even when the base tubes are arranged on the same plane, heat exchange gaps can still be maintained. (See reference...) Figure 2a The "I"-shaped fins refer to fins that are straight, with the fin ends directly connected to the base tube. Adjacent base tubes need to be staggered to leave heat exchange gaps. (Refer to...) Figure 2b .

[0045] The invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0046] like Figure 1a and Figure 1b As shown, this invention discloses a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler. The boiler is horizontally arranged and includes a blower 1, a burner 2, a burner head 22, a membrane water-cooled wall evaporator heat exchange tube bundle 3, a coupled finned tube evaporator heat exchange tube bundle 4, a coupled finned tube flue gas condenser heat exchange tube bundle 5, an upper steam-water chamber 6, a lower water chamber 7, an inlet header 8, an outlet header 9, a steam condensation heat exchange tube bundle 10, an upper header for the flue gas condensation section 11, a lower header for the flue gas condensation section 12, a vacuum pump 13, a boiler body shell plate 14, insulation material 15, a color steel plate 16, a condensate drain hole 17, and a chimney 18. Multiple heat exchange tubes form a vertically arranged heat exchange tube bank, and the space enclosed by the tube bank... This refers to the furnace chamber, where the upper and lower ends of all heat exchange tubes 2 extend into the upper steam-water chamber 6 and the lower water chamber 7, respectively. The upper steam-water chamber 6 and the lower water chamber 7 are square headers. Inside the upper steam-water chamber 6 are inlet headers 8 and outlet headers 9, with a vacuum pump 13 above. Above the boiler tail end is a square header, shorter than the upper steam-water chamber 6, which is the upper header 11 for the flue gas condensation section. Below the boiler tail end is the lower header 12 for the flue gas condensation section. The steam condensation heat exchange tube bundle 10 is arranged inside the upper steam-water chamber 6 and connected to the inlet header 8 and outlet header 9. A condensate drain hole 17 is located below the square-to-round flue shell 143 on the right side of the furnace body. The burner 2 and the front connecting plate 144 are fixed by flange connection. Figure 1b and Figure 1cThe furnace shell shown consists of a front connecting plate 144 on the flue gas inlet side, a left boiler body shell plate 141, a right boiler body shell plate 142, an equal pressure flue gas passage cover plate 145, and a square-to-round flue gas duct shell 143. A row of closely connected rear-end membrane water-cooled wall evaporative heat exchange tube bundles 32 are arranged at the rear of the furnace. These closely connected rear-end membrane water-cooled wall evaporative heat exchange tube bundles 32 are rectangular tube bundles welded together, forming a gap channel between adjacent heat exchange tubes on both sides of the central axis. The equal pressure flue gas passage is formed by the space between the left boiler body shell plate 141, the right boiler body shell plate 142, the equal pressure flue gas passage cover plate 145, and the P-shaped finned tubes. The left boiler body shell plate 141, the right boiler body shell plate 142, and the equal pressure flue gas passage cover plate 145 are welded and sealed. Similarly, the equal pressure flue gas passage cover plate is welded and sealed to the upper steam-water chamber 6 and the lower water chamber 7. Figure 1c and Figure 1d As shown, the heating return water enters from the lower header 12 of the flue gas condensing section, and then, constrained by the partitions in the upper header 11 and the lower header 12 of the flue gas condensing section, it moves back and forth to exchange heat with the tail flue gas before entering the inlet header 8 inside the upper steam-water chamber 6. It then flows through the steam condensation heat exchange tube bundle 10 to exchange heat with steam and finally leaves the boiler from the outlet header 9. Figure 1e As shown, a row of rectangular tubes with a central relief tube 29 is arranged in the front row. These tubes are welded together using the relief tube 29. The tightly joined surfaces of the rectangular tubes are welded together to seal the front end of the furnace membrane water-cooled wall evaporator heat exchange tube bundle 31. The burner head 22 can be inserted through the relief tube 29. The burner 2 is a fully premixed metal fiber surface burner 21 or a diffusion burner. Figure 6 As shown, when the boiler burner 2 adopts a diffusion burner, the boiler body shell plate 14 is composed of the left boiler body shell plate 141, the right boiler body shell plate 142, the equal pressure flue gas passage cover plate 145, and the square-to-round flue shell 143 on the flue gas inlet side. A row of membrane water-cooled wall evaporation heat exchange tube bundles 31 with a middle relief tube 29 are arranged in the front row and welded together to seal the front end of the furnace. The tube bundles are rectangular tubes 411 with relief tubes 29 in the middle and welded together. The diffusion burner can be inserted from the relief tube 29. The equal pressure flue gas passage is formed by the space between the left boiler body shell plate 141, the right boiler body shell plate 142, the equal pressure flue gas passage cover plate 145 and the P-shaped finned tube. Considering that the incomplete combustion loss of the gas caused by the flame root is large, the front end of the heat exchange tubes on both sides is welded and sealed to reduce the incomplete combustion loss. The coupled finned tube evaporator heat exchanger bundle 4 achieves radiation and laminar convection enhancement, while the coupled finned tube flue gas condenser heat exchanger bundle achieves laminar convection enhancement heat transfer.

[0047] like Figure 2a and Figure 2bAs shown, the P-shaped finned tube 19 consists of a rectangular base tube 191 and a fin 192 with a baffle column. The fin 192 with the baffle column adopts two shapes: "J" and "I". A 1-4 mm wide gap channel is formed between the P-shaped finned tube 19 and the base tube of the adjacent P-shaped finned tube 19. The baffle column of the fin 192 with the baffle column further expands the heat exchange area of ​​the fin and enhances heat exchange by turbulent flue gas. The fin is welded to the base tube by narrow-gap submerged arc automatic welding to form the P-shaped finned tube 19. TIG welding, MIG welding or laser welding can also be used between the base tube and the fin, with a single-sided V-shaped bevel and full penetration. The rectangular base tube 191 uses the materials specified in the gas boiler standard. The fin is not a pressure-bearing component and uses a material with high thermal conductivity. Figure 2c and Figure 2d As shown, the base tube of the Q-shaped finned tube 20 is a long oval tube 201 or an oblong tube. The fins 202 are welded to the side or top of the base tube and partially surround the adjacent base tube. The base tube and the fins are welded by TIG welding, MIG welding or laser welding, with a single-sided V-shaped bevel and full penetration. The turbulence-inducing columns on the fins are obtained in batches by spot welding. The long oval tube 201 of the base tube is made of the material specified in the gas boiler standard. The fins with turbulence-inducing columns are not pressure-bearing components and are made of materials with high thermal conductivity.

[0048] like Figure 3a As shown, the P-shaped finned tube 19 is precisely positioned using a welding bed 23 during welding. The welding bed 23 is slightly wider than the base tube by 2-4 mm to ensure a gap channel is formed between the welded fins and the next adjacent base tube. The welding bed 23 has protrusions 232 for supporting the base tube, and movable pressure plates 231 on both sides of the welding bed 23 for fixing the fins. Narrow-gap submerged arc automatic welding is used to achieve mass production. Figure 3b The P-shaped finned tube 19 shown can also be formed by bending 3mm flat steel three times to form an "I" shaped fin, or by bending it four times to form a "J" shaped fin. The fins and the base tube are then fully welded together by TIG welding, MIG welding or laser welding.

[0049] like Figure 4a and Figure 4b As shown, a 1-2 mm metal sheet is added between the upper and lower ends of adjacent heat exchange tubes in the coupled finned tube evaporator heat exchange tube bundle 4 and the coupled finned tube flue gas condenser heat exchange tube bundle 5. The upper surface of the upper metal sheet and the upper surface of the coupled finned tube flue gas condenser heat exchange tube bundle 5 are on the same plane, and the lower surface of the lower metal sheet and the lower surface of the coupled finned tube flue gas condenser heat exchange tube bundle 5 are on the same surface. The metal sheet is used to form a gap channel between tubes and can reduce the processing difficulty of the tube sheet, eliminating the need to open a separate hole on the tube sheet. The fin length is less than the heat exchange tube length, and the metal sheet is used to form a gap channel between tubes.

[0050] like Figure 5a , Figure 5b and Figure 5c As shown, the cross-section of the turbulence column on the straight fin with turbulence jet can be cylindrical, square, or triangular.

[0051] like Figure 6 As shown, when the burner 2 adopts a diffusion burner, its structure is basically the same as that of the fully premixed metal fiber surface burner. The difference is that the front end of the left evaporative heat exchange tube bundle 41 and the right evaporative heat exchange tube bundle 42 are welded and sealed. Considering that the incomplete combustion loss of gas caused by the flame root is large when using a diffusion burner, the front end of the heat exchange tubes on both sides are welded and sealed to reduce the incomplete combustion loss.

[0052] like Figure 7a , Figure 7b , Figure 7c and Figure 7d As shown, burner 2 can also be a fully premixed water-cooled burner. A round-to-square structure 24 is set on the furnace shell, and the round-to-square structure 24 is connected to the fully premixed water-cooled burner. The membrane water-cooled wall evaporation heat exchange tube bundle 31 at the front end of the furnace adopts a V-shaped or U-shaped arrangement to form a V-shaped or U-shaped water-cooled combustion surface. There are gaps between the tube bundles. The premixed gas is distributed to the entire V-shaped or U-shaped surface through the round-to-square structure 24, and then passes through the gaps between the tube bundles for ignition and combustion. In addition, when the membrane water-cooled wall evaporation heat exchange tube bundle 31 at the front end of the furnace adopts a V-shaped or U-shaped arrangement, the tube bundle extends to the membrane water-cooled wall evaporation heat exchange tube bundle 32 at the rear end, which can make the boiler have a double furnace shape. The advantage of using a fully premixed water-cooled burner is that it can greatly reduce the furnace volume. The V-shaped or U-shaped arrangement refers to the V-shaped or U-shaped appearance of the membrane water-cooled wall evaporation heat exchange tube bundle 31 at the front end of the furnace in a top view.

[0053] like Figure 8a As shown, when the burner 2 adopts a fully premixed water-cooled burner, two or four burners can be set to increase the boiler capacity. When two fully premixed water-cooled burners are used, the coupled finned tube flue gas condenser heat exchange tube bundle 5 is arranged on both sides of the boiler. The burners are arranged in opposite directions. The flue gas enters the furnace from both the front and rear sides at the same time. The high-temperature flue gas formed after combustion undergoes laminar flow enhanced heat exchange along the gap channels of the left and right adjacent evaporation heat exchange tube bundles 41 and 42 on the left and right sides of the furnace central axis. After the flue gas flows out at 90°, it moves forward and then turns 90° to the outside of the boiler before scouring the coupled finned tube flue gas condenser heat exchange tube bundle 5 to continue cooling. After being collected through the square-to-round flue shell 143, it is discharged into the atmosphere through the chimney 18.

[0054] like Figure 8b and Figure 8cAs shown, the heating return water enters from both sides of the boiler simultaneously. The boiler's heating return water flows from the lower header 12 of the flue gas condensing section through the heat exchange tube bundle 5 of the coupled finned tube flue gas condenser to the upper header 11 of the flue gas condensing section. After being heated, it enters the steam condensation heat exchange tube bundle 10 from the inlet header 8 to absorb the heat from the condensation of water vapor in the upper steam-water chamber, and then is delivered to the heating users through the outlet header 9.

[0055] like Figure 9a As shown, the coupled finned tube evaporator heat exchanger bundle 4 can utilize P-shaped finned tubes 19 + double P mirrored tubes. The combination of the "-shaped finned tube 25" or the "W-shaped finned tube 26" allows the flue gas to undergo three heat exchanges in the slit channel, resulting in a three-pass flue gas flow; such as Figure 9b As shown, the double P mirror " The finned tube 25 consists of a base rectangular tube 191 and two fins 192 with turbulence-inducing columns; double P mirror image. "The finned tube 25 is mirrored with the adjacent double P" A 1-4 mm wide gap channel is formed between the base tubes of the finned tube 25; the temperature of the flue gas decreases as it enters the latter half of the tube, greatly reducing the heat exchange temperature difference between the flue gas and the water in the water-cooled tube wall. Using two fins 192 with turbulence-inducing columns further increases the convective heating surface and the degree of flue gas turbulence, enhancing heat transfer and improving boiler thermal efficiency; Figure 9c As shown, the W-shaped finned tube 26 consists of a base rectangular tube 191, a fin 192 with a turbulence-inducing column, and a smooth straight fin 193. The W-shaped finned tube 26, compared to the double-P mirror image... "The finned tube 25 has lower resistance and is more conducive to the flow of flue gas."

[0056] like Figure 10a , Figure 10b and Figure 10c As shown, the heat exchange tube bundles of the membrane water-cooled wall evaporation heat exchange tube bundle 3 and the coupled finned tube evaporation heat exchange tube bundle can also be arranged in a trapezoidal shape. When the heat exchange tube bundle is arranged in a trapezoidal shape, the coupled finned tube evaporation heat exchange tube bundle adopts the P-shaped finned tube 19 with "I" shaped fins or the Q-shaped finned tube 20 with tile fins. When the heat exchange tube bundle is arranged in a trapezoidal shape, the boiler volume can be reduced and a natural isobaric flue gas channel can be formed.

[0057] like Figure 11a and Figure 11b As shown, the steam condensation heat exchange tube bundle 10 is arranged in a staggered pattern. The bottom two or three rows of the tube bundle are welded with V-shaped liquid guiding fins 101 or U-shaped liquid guiding fins 102. Due to the existence of the tube bundle effect, the heat exchange capacity of the steam condensation heat exchange tube bundle 10 is reduced. In order to save materials and manufacturing costs, liquid guiding fins are welded on the tube bundle where the tube bundle effect is more severe, which can improve the overall heat exchange capacity.

[0058] like Figure 12As shown, the steam condensation heat exchange tube bundle 10 can adopt an upper staggered arrangement and a lower M-shaped tube arrangement. The M-shaped tube arrangement specifically means that the lower steam condensation heat exchange tube bundle is divided into several parts, and each part is separated by a set area where no steam condensation heat exchange tube bundle is arranged. Furthermore, the number of steam condensation heat exchange tube bundles in each part gradually decreases from top to bottom. At this time, it is not necessary to weld liquid guiding fins to the bottom tube bundle. The bottom M-shaped tube arrangement can guide the condensate to the lower part of the upper steam-water chamber 6 in a timely manner, reducing the tube bundle effect.

[0059] like Figure 13 As shown, the structure of the gas-fired vacuum phase change hot water boiler can also be used in non-vacuum hot water boilers. In the gas-fired vacuum phase change hot water boiler described above, the upper steam-water chamber 6 and the lower water chamber 7 are removed. The two ends of the membrane water-cooled wall evaporator heat exchange tube bundle 3, the coupled finned tube evaporator heat exchange tube bundle 4, and the coupled finned tube flue gas condenser heat exchange tube bundle 5 are directly connected to the upper header 27 and the lower header 28. Vertical baffles are provided in the upper header 27 and the lower header 28. A return water inlet is provided at the rear of the upper header 27. The return water enters from the return water inlet above the upper header 27 of the non-vacuum hot water boiler, and flows back under the constraint of the baffles in the upper header 27 and the lower header 28 of the non-vacuum hot water boiler before leaving the boiler.

[0060] This invention proposes a rectangular cross-section coupled finned tube gas-fired vacuum phase change hot water boiler, which has the advantages of thermal efficiency of over 97%, flue gas resistance of less than 1000Pa, small size, low cost, uniform boiler heat load distribution, and high heat exchange capacity.

Claims

1. A coupled finned tube gas vacuum phase change hot water boiler, characterized in that, The furnace is arranged horizontally and includes a burner (2), a membrane water-cooled wall evaporative heat exchange tube bundle (3), a coupled finned tube evaporative heat exchange tube bundle (4), a coupled finned tube flue gas condenser heat exchange tube bundle (5), an upper steam-water chamber (6), a lower water chamber (7), and a chimney (18). The burner (2) outlet is connected to the sealed furnace space. The membrane water-cooled wall evaporative heat exchange tube bundle (3) is located before and after the sealed furnace space. The coupled finned tube evaporative heat exchange tube bundle (4) is located on both sides of the sealed furnace space. The upper steam-water chamber (6) and the lower... The water chamber (7) is located above and below the sealed space of the furnace, respectively; the coupled finned tube flue gas condenser heat exchange tube bundle (5) and the chimney (18) are arranged behind the furnace along the flue gas flow direction; the coupled finned tube evaporator heat exchange tube bundle (4) and the coupled finned tube flue gas condenser heat exchange tube bundle (5) adopt slit heat exchange tube bundle; the slit heat exchange tube bundle includes a base tube and fins, the fins are fixedly connected to the base tube to form a heat exchange tube, several heat exchange tubes are arranged in the same direction, there is a slit channel between two adjacent heat exchange tubes, and there is a slit channel between the fins and their adjacent base tubes.

2. The coupled fin tube gas vacuum phase change hot water boiler according to claim 1, characterized in that, The upper and lower ends of the coupled finned tube flue gas condenser heat exchange tube bundle (5) are respectively connected to the upper header (11) of the flue gas condensing section and the lower header (12) of the flue gas condensing section. The upper header (11) of the flue gas condensing section is connected in sequence to the inlet header (8), the steam condensation heat exchange tube bundle (10) and the outlet header (9); a vacuum pump (13) is installed at the top of the upper steam-water chamber (6).

3. The coupled fin tube gas vacuum phase change hot water boiler according to claim 1, characterized in that, A 1-2 mm metal sheet is provided between the two ends of two adjacent heat exchange tubes. The metal sheet is flush with the end face of the heat exchange tube and the fin length is less than the heat exchange tube length. The metal sheet is used to form a gap channel between the tubes. The base tube adopts the material specified in the standard for gas boilers, and the thermal conductivity of the material used for the fins is not less than 200 W / (m·K).

4. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, A rectangular base tube (191) and a fin with a turbulence column (192) are welded to form a P-shaped finned tube (19). The coupled finned tube evaporator heat exchange tube bundle (4) adopts a P-shaped finned tube (19). The fin with a turbulence column (192) adopts two shapes: "J" and "I". The P-shaped finned tubes (19) are arranged in the same direction, and a 1-4 mm wide gap channel is formed between the P-shaped finned tube (19) and the base tube of the adjacent P-shaped finned tube (19). The coupled finned tube flue gas condenser heat exchange tube bundle (5) adopts a P-shaped finned tube (19) with an "I" shaped fin.

5. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 4, characterized in that, The P-shaped finned tube (19) is formed by bending the flat steel three times to form an "I" shaped fin, and by bending it four times to form a "J" shaped fin.

6. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, Coupled finned tube evaporator heat exchanger bundle (4) using P-shaped finned tubes (19) + double P mirror" The combination of finned tubes (25) allows the flue gas to undergo three heat exchanges in the slit channel, resulting in a three-pass flue gas flow and a double-P mirror image. "The finned tube (25) comprises a base rectangular tube (191) and two fins (192) with turbulence-inducing columns; double P mirror" "The finned tube (25) is mirrored with the adjacent double P" A 1-4 mm wide slit channel is formed between the base tubes of the finned tube (25).

7. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, The coupled finned tube evaporation heat exchange tube bundle (4) uses a P-shaped finned tube (19) + a W-shaped finned tube (26). The W-shaped finned tube (26) includes a base tube rectangular tube (191), a fin (192) with a turbulence column and a smooth straight fin (193). The fin (192) with a turbulence column and the smooth straight fin (193) are respectively set on two opposite edges of the base tube rectangular tube (131).

8. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 7, characterized in that, The P-shaped finned tube (19) is positioned by a welding bed (23) during welding; the width of the welding bed (23) is 2-4 mm wider than the base tube, and the welding bed (23) has a protrusion (232) for supporting the base tube. The welding bed (23) has movable pressure plates (231) on both sides for fixing the fins. It is mass-produced by narrow-gap submerged arc automatic welding.

9. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, The base tube and the tile fin (202) are welded to form a tile fin Q-shaped finned tube (20). The coupled finned tube evaporation heat exchange tube bundle (4) adopts a tile fin Q-shaped finned tube (20). The tile fin (202) is welded to the top or side of the base tube and partially surrounds the adjacent base tube. The base tube adopts a long oval tube (201) or a waist-shaped tube.

10. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 9, characterized in that, The heat exchange tube bundle (5) of the coupled finned tube flue gas condenser adopts tile-finned Q-shaped finned tubes (20).

11. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, The coupled finned tube evaporation heat exchange tube bundle (4) is arranged in parallel or trapezoidal arrangement. When the heat exchange tube bundle is arranged in trapezoidal arrangement, the coupled finned tube evaporation heat exchange tube bundle (4) adopts "I" shaped finned P-shaped finned tube (19) or tile finned Q-shaped finned tube (20).

12. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, The base tube and fins are welded using narrow-gap submerged arc welding, TIG welding, MIG welding or laser welding processes, with a single-sided V-shaped bevel and full penetration.

13. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, The burners (2) are respectively pre-premixed or post-premixed fully premixed metal fiber surface burners, diffusion burners or post-premixed fully premixed water-cooled burners.

14. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, When the burner (2) is a diffusion burner, several heat exchange tubes at the front end of the coupled finned tube evaporation heat exchange tube bundle (4) are welded and sealed.

15. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, The burner (2) is a fully premixed water-cooled burner. A round-to-square structure (24) is set on the furnace shell. The round-to-square structure (24) is used to connect the fully premixed water-cooled burner and the furnace shell. The membrane water-cooled wall evaporation heat exchange tube bundle (31) at the front end of the furnace is arranged in a V-shape or U-shape to form a V-shaped or U-shaped water-cooled combustion surface. There are gaps between the tube bundles. The premixed gas is distributed to the entire V-shaped or U-shaped combustion surface through the round-to-square structure (24) and then passes through the gaps between the tube bundles to ignite and burn.

16. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 15, characterized in that: The tube bank extends to the rear membrane water-cooled wall evaporative heat exchange tube bundle (32), making the boiler a dual-furnace type.

17. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, When the burner (2) adopts a fully premixed water-cooled burner, two or four burners are used. When two fully premixed water-cooled burners are used, the coupled finned tube flue gas condenser heat exchange tube bundle (5) is arranged on both sides of the boiler. The burners (2) are arranged in opposite directions. The flue gas enters the furnace from both the front and rear sides at the same time. The high-temperature flue gas formed after combustion undergoes laminar flow enhanced heat exchange along the gap channel of the coupled finned tube evaporation heat exchange tube bundle (4). After the flue gas turns 90° and flows out, it moves forward and then turns 90° to the outside of the boiler before scouring the coupled finned tube flue gas condenser heat exchange tube bundle to continue cooling. After that, it is collected through the square-to-round flue shell (143) and discharged into the atmosphere through the chimney (18).

18. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, The steam condensation heat exchange tube bundle (10) adopts a circular bare tube. The steam condensation heat exchange tube bundle (10) is arranged in a staggered manner. The bottom two or three rows of the tube bundle are welded with V-shaped liquid guiding fins (101) or U-shaped liquid guiding fins (102).

19. The coupled finned tube gas-fired vacuum phase change hot water boiler according to claim 1, characterized in that, The steam condensation heat exchange tube bundle (10) adopts an upper staggered arrangement, and the lower steam condensation heat exchange tube bundle is divided into several parts. Each part is separated by a set area where no steam condensation heat exchange tube bundle is arranged, and the number of steam condensation heat exchange tube bundles in each part gradually decreases from top to bottom.

20. A non-vacuum hot water boiler, characterized in that, Based on the coupled finned tube gas-fired vacuum phase change hot water boiler according to any one of claims 1-19, the two ends of the membrane water-cooled wall evaporation heat exchange tube bundle (3), the coupled finned tube evaporation heat exchange tube bundle (4), and the coupled finned tube flue gas condenser heat exchange tube bundle (5) are directly connected to the upper header (27) and the lower header (28), and vertical baffles are provided in the upper header (27) and the lower header (28). A return water inlet is provided at the rear of the upper header (27), and the return water enters from the return water inlet above the upper header (27). A return water outlet is provided at the front of the upper header (27), and the water flows back and leaves the boiler under the constraint of the baffles in the upper header (27) and the lower header (28).

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