A fully premixed condensing steam boiler that prevents dry burning and facilitates drainage

Abstract

This invention discloses a fully premixed condensing steam boiler with anti-dry-burning and easy drainage design. The combustion heat exchange device includes an encapsulated shell, a burner, a high-temperature heat exchange module, a superheated heat exchange module, a condensing heat exchange module, and steam heat exchange pipelines. The steam heat exchange pipelines include a water inlet section, a condensing heat exchange section, an external connection section, a fluid heat exchange section, a high-temperature heat exchange section, and a steam outlet section connected in sequence. The external connection section is equipped with a circulating water pump and a drain valve. The steam outlet section is equipped with a steam backflow detection component. In this invention, the steam heat exchange pipelines do not have a looping path and do not have a "U"-shaped flow structure, allowing water inside the steam heat exchange pipelines to flow downwards and drain more smoothly. Drainage from two sections results in better drainage and reduces the likelihood of blockage. Furthermore, it can detect whether steam has returned to the high-temperature heat exchange section and promptly issue alarms and initiate shutdown operations to prevent dry burning.

Description

Technical Field

[0001] This invention relates to the field of steam boiler technology, and in particular to a fully premixed condensing steam boiler that is protected against dry burning and facilitates drainage. Background Technology

[0002] A steam boiler refers to boiler equipment that produces steam. Steam boilers have higher combustion temperatures, resulting in flue gas temperatures significantly higher than conventional boilers, typically exceeding 200°C. Consequently, the latent heat of water vapor in the flue gas is not fully utilized. Therefore, condensing boilers have been introduced to the market. These boilers use heat recovery equipment to lower the flue gas temperature below the flue gas dew point (or water dew point), thereby improving energy efficiency. Currently, condensing boilers on the market mainly come in two structural forms: separate and integrated. During operation, water vapor reflux occurs. When water vapor refluxes to the high-temperature area near the burner, the heat exchange pipes come into contact with the water vapor at a high temperature of 1000 to 1300°C, which can easily lead to corrosion or cracking, causing damage to the steam boiler and shortening its service life.

[0003] Therefore, the market has seen the introduction of products such as a fully premixed condensing steam boiler disclosed in patent CN202221790148.6, and a fully premixed condensing combustion heat exchange device for a steam boiler disclosed in patent CN202221790365.5. The combustion heat exchange device comprises, from top to bottom, a high-temperature heat exchange module, a superheated heat exchange module, and a condensing heat exchange module; the burner burns downwards near the top of the combustion heat exchange device and exhausts flue gas from the bottom; the main body of the steam heat exchange pipeline flows upwards, with the flow returning to the superheated heat exchange module area in the middle. The heat exchange temperature in this area is within the range of 500 to 700°C, and within this ambient temperature range, the metal heat exchange tubes are less susceptible to corrosion and damage from water vapor.

[0004] When a fully premixed condensing steam boiler is prepared for a prolonged standby period, water needs to be drained from the steam heat exchange pipes to reduce corrosion. However, in actual use, it has been found that in colder northern regions or high-altitude areas, the aforementioned combustion heat exchange device exhibits a U-shaped flow structure. Water tends to accumulate in the middle superheated heat exchange module, making it difficult to drain and causing it to freeze, thus exacerbating corrosion or clogging the steam heat exchange pipes. Therefore, further improvements are needed. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a fully premixed condensing steam boiler that is prevents dry burning and facilitates drainage.

[0006] One embodiment of the present invention adopts the following technical solution to solve its technical problem: a fully premixed condensing steam boiler that is prevented from dry burning and easy to drain water, comprising: several combustion heat exchange devices, an integrated steam output pipe and an integrated water input pipe;

[0007] The combustion heat exchange device includes an encapsulation base shell, a burner, a high-temperature heat exchange module, a superheated heat exchange module, a condensation heat exchange module, and a steam heat exchange pipeline; the encapsulation base shell has an air inlet and an air outlet, and the burner, the high-temperature heat exchange module, the superheated heat exchange module, and the condensation heat exchange module are sequentially arranged inside the encapsulation base shell along the path from the air inlet to the air outlet.

[0008] The steam heat exchange pipeline includes a water inlet section, a condensation heat exchange section, an external connection section, a fluid heat exchange section, a high-temperature heat exchange section, and a steam outlet section connected in sequence; the condensation heat exchange section is located in the condensation heat exchange module; the fluid heat exchange section is located in the superheat heat exchange module; the high-temperature heat exchange section is located in the high-temperature heat exchange module; the water inlet section is connected to the integrated water inlet pipeline; and the steam outlet section is connected to the integrated steam outlet pipeline.

[0009] The external connection section is equipped with a circulating water pump and a drain valve; the steam output section is equipped with a steam reflux detection component, which can detect whether the steam in the steam output section refluxes back to the high-temperature heat exchange section.

[0010] Optionally, the steam reflux detection component includes a bypass water box and a water level probe; the steam output section is arranged vertically, and the bypass water box is connected in parallel to one side of the steam output section; the liquid level of the steam output section is the same as the liquid level of the bypass water box, and the water level probe can detect the water level of the bypass water box.

[0011] Optionally, the bypass water box and the steam output section are provided with two bypass pipes in a vertical direction; the two bypass pipes are respectively located near the top and bottom of the bypass water box; the water level probe is installed at the top of the bypass water box and extends to the bottom of the bypass pipe.

[0012] Optionally, the steam heat exchange tubes are arranged in a multi-layered, meandering pipeline structure from bottom to top within the condensation heat exchange module, the superheat heat exchange module, and the high-temperature heat exchange module.

[0013] Optionally, the external connection section is also equipped with a pressure-stabilizing water tank, with the inlet and outlet of the pressure-stabilizing water tank located at the bottom of the pressure-stabilizing water tank, and the air in the water circuit of the condensation heat exchange module can be collected in the pressure-stabilizing water tank.

[0014] Optionally, the steam heat exchange pipeline is one or more of the following: flat tube, round tube, rectangular tube, or finned tube.

[0015] Optionally, the integrated steam output pipeline is equipped with a pressure gauge, a thermometer, and a pressure relief valve.

[0016] The beneficial effects of this invention are as follows: Within the condensing heat exchange module, superheating heat exchange module, and high-temperature heat exchange module, the overall path of the steam heat exchange pipeline is arranged along a multi-layered, top-down, meandering pipeline structure. There is no central superheating heat exchange module, and the steam heat exchange pipeline does not have a looping path or a "U"-shaped flow structure. Water inside the steam heat exchange pipeline can flow downwards more smoothly and be discharged under the influence of gravity. Furthermore, an external pipeline with an external connection section is provided between the condensing heat exchange section and the fluid heat exchange section. A circulating water pump is installed on this external pipeline to ensure sufficient water pressure in the steam heat exchange pipeline. Simultaneously, a drain valve is installed on this external pipeline, allowing drainage at the water inlet of the superheating heat exchange module. The drainage areas of the combustion heat exchange device are divided between the central external pipeline and the bottom water inlet section, allowing drainage from both sections, resulting in better drainage and reducing the likelihood of blockage. Furthermore, a steam backflow detection component is installed in the steam output section. This component can detect whether the steam in the steam output section flows back to the high-temperature heat exchange section and issue an alarm and shutdown operation in a timely manner to avoid the risk of dry burning.

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 This is a schematic diagram of the structure of the fully premixed condensing steam boiler of the present invention;

[0020] Figure 2 for Figure 1 A schematic diagram of the structure of the combustion heat exchanger after the encapsulation base shell has been removed;

[0021] Figure 3 for Figure 1 Longitudinal sectional view of the steam reflux detection component location of the fully premixed condensing steam boiler;

[0022] Figure 4 This is a schematic diagram of the channel routing of the steam heat exchange pipeline in the combustion heat exchange device of the present invention.

[0023] Explanation of key component symbols:

[0024] 100. Combustion heat exchange device; 110. Encapsulation base shell; 111. Air inlet; 112. Air outlet; 120. Burner; 130. High-temperature heat exchange module; 140. Superheated heat exchange module; 150. Condensation heat exchange module; 160. Steam heat exchange pipeline; 161. Water input section; 162. Condensation heat exchange section; 163. External connection section; 164. Fluid heat exchange section; 165. High-temperature heat exchange section; 166. Steam output section; 170. Circulating water pump; 171. Pressure stabilizing water tank; 180. Drain valve; 190. Steam reflux detection component; 191. Bypass water box; 192. Water level probe; 193. Bypass pipeline;

[0025] 200. Steam integrated output pipeline; 300. Water integrated input pipeline. Detailed Implementation

[0026] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0027] In the description of this invention, "multiple" means two or more; "greater than," "less than," and "exceeding" are understood to exclude the stated number; "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0028] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limiting this invention.

[0029] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to a fixed connection, a detachable connection, or an integrally formed connection; they can refer to a mechanical connection; they can refer to the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0030] Example

[0031] Reference Figures 1 to 4The present invention proposes a fully premixed condensing steam boiler that is resistant to dry burning and easy to drain water, comprising: several combustion heat exchange devices 100, an integrated steam output pipe 200, and an integrated water input pipe 300.

[0032] The combustion heat exchange device 100 includes an encapsulation base shell 110, a burner 120, a high-temperature heat exchange module 130, a superheated heat exchange module 140, a condensation heat exchange module 150, and a steam heat exchange pipeline 160. The encapsulation base shell 110 has an air inlet 111 and an air outlet 112. The burner 120, the high-temperature heat exchange module 130, the superheated heat exchange module 140, and the condensation heat exchange module 150 are arranged sequentially inside the encapsulation base shell 110 along the path from the air inlet 111 to the air outlet 112.

[0033] The steam heat exchange pipeline 160 includes a water inlet section 161, a condensation heat exchange section 162, an external connection section 163, a fluid heat exchange section 164, a high-temperature heat exchange section 165, and a steam outlet section 166 connected in sequence. The condensation heat exchange section 162 is located in the condensation heat exchange module 150; the fluid heat exchange section 164 is located in the superheat heat exchange module 140; the high-temperature heat exchange section 165 is located in the high-temperature heat exchange module 130; the water inlet section 161 is connected to the integrated water inlet pipeline 300; and the steam outlet section 166 is connected to the integrated steam outlet pipeline 200.

[0034] The external connection section 163 is equipped with a circulating water pump 170 and a drain valve 180; the steam output section 166 is equipped with a steam reflux detection component 190, which can detect whether the steam in the steam output section 166 refluxes back to the high-temperature heat exchange section 165.

[0035] In this invention, the steam heat exchange pipeline 160 is arranged along a multi-layered, meandering pipeline structure from bottom to top within the condensation heat exchange module 150, the superheated heat exchange module 140, and the high-temperature heat exchange module 130. The middle superheated heat exchange module 140 is not provided, and the steam heat exchange pipeline 160 does not have a looping path. There is no "U"-shaped flow structure. Under the action of gravity, the water inside the steam heat exchange pipeline 160 can flow downwards more smoothly and be discharged. Furthermore, an external pipeline with an external connection section 163 is provided between the condensation heat exchange section 162 and the fluid heat exchange section 164. A circulating water pump 170 is installed on this external pipeline to ensure sufficient water pressure for the water flow in the steam heat exchange pipeline 160. At the same time, a drain valve 180 is installed on this external pipeline to drain water at the water inlet of the superheated heat exchange module 140. The drainage area of ​​the combustion heat exchange device 100 is divided into the external pipeline in the middle and the water inlet section 161 at the bottom, allowing drainage from two sections, resulting in better drainage and less likelihood of blockage. Furthermore, a steam backflow detection component 190 is provided in the steam output section 166. This steam backflow detection component 190 can detect whether the steam in the steam output section 166 flows back to the high-temperature heat exchange section 165 and issue an alarm and shutdown operation in time to avoid the risk of dry burning.

[0036] In this embodiment, since the overall water path is arranged along a multi-layered, meandering pipeline structure from bottom to top, the high-temperature heat exchange section 165 is located within the high-temperature heat exchange module 130. The operating temperature in this area is approximately 1000 to 1300°C. If the steam output section 166 flows back to this heat exchange section, corrosion or cracking is likely to occur. Therefore, the overall bottom-to-top pipeline arrangement requires the addition of a reliable steam backflow detection component 190 to ensure the safe operation of the combustion heat exchange device 100.

[0037] In this embodiment, the steam reflux detection component 190 includes a bypass water box 191 and a water level probe 192. The steam output section 166 is arranged vertically, and the bypass water box 191 is connected in parallel to one side of the steam output section 166. The liquid level in the steam output section 166 is the same as the liquid level in the bypass water box 191, and the water level probe 192 can detect the water level in the bypass water box 191. The bypass water box 191 is connected in parallel to one side of the steam output section 166, which can synchronize the water level in the steam output section 166. During the rising process, the water in the steam output section 166 is gradually converted into high-temperature steam and transported to the integrated steam output pipeline 200. During this conversion process, the water level will fluctuate, and the bypass water box 191 provides a large water storage and conversion chamber, which can effectively reduce the fluctuation of the water level. By adjusting the arrangement, the water level converted by steam can remain in the bypass water box for a large range during the normal operation of the steam boiler. If steam backflow occurs, the water levels in the steam output section 166 and the bypass water box 191 will drop rapidly. If the water level probe 192 detects that the water level in the bypass water box 191 is insufficient or cannot detect water, it is determined that steam backflow has occurred in the steam heat exchange pipeline 160 of the combustion heat exchange device 100. The probe will promptly send an electrical signal to the control center to issue an alarm or take timely shutdown measures to avoid the risk of dry burning.

[0038] Specifically, the bypass water box 191 and the steam output section 166 are vertically connected by two bypass pipes 193; the two bypass pipes 193 are respectively located near the top and bottom of the bypass water box 191; a water level probe 192 is installed at the top of the bypass water box 191, and its bottom extends to the bottom bypass pipe 193. The bottom of the water level probe 192 extending to the bottom bypass pipe 193 can accurately detect whether the water in the bypass water box 191 flows back into the high-temperature heat exchange section 165.

[0039] In this embodiment, the steam heat exchange tubes are arranged in a multi-layered, meandering pipeline structure from bottom to top within the condensing heat exchange module 150, the superheating heat exchange module 140, and the high-temperature heat exchange module 130. Depending on the layout requirements of the combustion heat exchange device 100 and in conjunction with existing technologies, a single-channel coil structure, or a structure with multiple heat exchange tubes and rotating ports arranged in a reciprocating meandering pattern, or other existing pipe routing structures of the steam boiler combustion heat exchange device 100 can be used.

[0040] Specifically, those skilled in the art can refer to the piping structure of the condensation heat exchange module 150, the superheat heat exchange module 140, and the high-temperature heat exchange module 130 for guidance on setting up the piping components.

[0041] In some embodiments, the external connection section 163 is further provided with a pressure-stabilizing water tank 171. The inlet and outlet of the pressure-stabilizing water tank 171 are located at the bottom of the pressure-stabilizing water tank 171, allowing air in the water path within the condensing heat exchange module 150 to accumulate in the pressure-stabilizing water tank 171. When water from the condensing heat exchange section 162 within the condensing heat exchange module 150 passes through the pressure-stabilizing water tank 171 of the external connection section 163, air bubbles in the water path can be collected by the pressure-stabilizing water tank 171, thereby reducing air bubbles in the subsequent fluid heat exchange section 164 and high-temperature heat exchange section 165, reducing corrosion and operating noise.

[0042] Specifically, the pressure-stabilizing water tank 171 can be configured as an expansion tank, with an elastic diaphragm structure installed at the top.

[0043] In this embodiment, based on the arrangement of the combustion heat exchange device 100 and the product positioning, the steam heat exchange pipeline 160 is one or more combinations of flat tube, round tube, rectangular tube or finned tube.

[0044] In this embodiment, the integrated steam output pipeline 200 is equipped with a pressure gauge, a thermometer, and a pressure relief valve. The pressure gauge can detect the steam pressure value inside the steam output pipeline, the thermometer can detect the steam temperature inside the steam output pipeline, and the pressure relief valve can partially discharge the steam inside the steam output pipeline to reduce the steam pressure inside the steam output pipeline.

[0045] Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications and substitutions are included within the scope defined by the claims of this application.

Claims

1. A dry-burning-preventing, easy-drainage, fully-premixed, condensing steam boiler, characterized in that, include: Several combustion heat exchange devices (100), integrated steam output pipeline (200) and integrated water input pipeline (300); The combustion heat exchange device (100) includes an encapsulation base shell (110), a burner (120), a high-temperature heat exchange module (130), a superheated heat exchange module (140), a condensation heat exchange module (150), and a steam heat exchange pipeline (160). The encapsulation base shell (110) has an air inlet (111) and an air outlet (112). The burner (120), the high-temperature heat exchange module (130), the superheated heat exchange module (140), and the condensation heat exchange module (150) are arranged sequentially in the encapsulation base shell (110) along the path from the air inlet (111) to the air outlet (112). The steam heat exchange pipeline (160) includes a water inlet section (161), a condensation heat exchange section (162), an external connection section (163), a fluid heat exchange section (164), a high-temperature heat exchange section (165), and a steam outlet section (166) connected in sequence. The condensation heat exchange section (162) is located in the condensation heat exchange module (150). The fluid heat exchange section (164) is located in the superheat heat exchange module (140). The high-temperature heat exchange section (165) is located in the high-temperature heat exchange module (130). The water inlet section (161) is connected to the integrated water inlet pipeline (300). The steam outlet section (166) is connected to the integrated steam outlet pipeline (200). The external connection section (163) is equipped with a circulating water pump (170) and a drain valve (180); the steam output section (166) is equipped with a steam reflux detection component (190), which can detect whether the steam in the steam output section (166) refluxes back to the high temperature heat exchange section (165). The steam reflux detection assembly (190) includes a bypass water box (191) and a water level probe (192); the steam output section (166) is arranged vertically, and the bypass water box (191) is connected in parallel to one side of the steam output section (166); the liquid level of the steam output section (166) is the same as the liquid level of the bypass water box (191), and the water level probe (192) can detect the water level of the bypass water box (191); The bypass water box (191) and the steam output section (166) are provided with two bypass pipes (193) in a vertical direction; the two bypass pipes (193) are respectively located near the top and bottom of the bypass water box (191); the water level probe (192) is installed at the top of the bypass water box (191) and extends to the bottom of the bypass pipe (193); The steam heat exchange pipeline (160) is arranged in the condensation heat exchange module (150), the superheat heat exchange module (140) and the high temperature heat exchange module (130) along a multi-layered meandering pipeline structure from bottom to top; The external connection section (163) is also provided with a pressure stabilizing water tank (171). The inlet and outlet of the pressure stabilizing water tank (171) are located at the bottom of the pressure stabilizing water tank (171). The air in the water path of the condensation heat exchange module (150) can be collected in the pressure stabilizing water tank (171).

2. The fully premixed condensing steam boiler with anti-dry-burning and easy drainage according to claim 1, characterized in that: The steam heat exchange pipeline (160) is one or more of the following: flat tube, round tube, rectangular tube, or finned tube.

3. The fully premixed condensing steam boiler with anti-dry-burning and easy drainage according to claim 1, characterized in that: The integrated steam output pipeline (200) is equipped with a pressure gauge, a thermometer, and a pressure relief valve.

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