Waste heat recovery device of gas-fired boiler

Abstract

The utility model relates to the technical field of gas-fired boilers, in particular to a gas-fired boiler waste heat recovery device which comprises a recovery box, a gas collecting pipe arranged in the recovery box, a hot gas inlet pipe, a cold gas outlet pipe and a water scraping assembly arranged in the recovery box, a cold air inlet pipe communicated with the interior of the recycling box is arranged on one side of the recycling box, a hot air outlet pipe communicated with the interior of the recycling box is arranged on the other side of the recycling box, and the water scraping assembly is used for scraping water vapor condensed and gathered on the outer side wall of the air collecting pipe; the water vapor in the discharged flue gas is condensed and gathered on the outer side wall of the gas collecting pipe, and is scraped by the water scraping assembly, so that the contact area between the discharged flue gas and the gas collecting pipe is ensured, and the heat exchange effect is better; the waste heat recovery device can effectively prevent water vapor condensed liquid drops from being gathered on the pipe wall of the gas collecting pipe, the contact area between exhausted flue gas and the gas collecting pipe is guaranteed, and the whole waste heat recovery effect is better.

Description

Technical Field

[0001] This utility model relates to the field of gas boiler technology, specifically a waste heat recovery device for gas boilers. Background Technology

[0002] Gas-fired boilers produce exhaust gas after burning fuel gas (such as natural gas), which contains a large amount of water vapor. The exhaust gas temperature is approximately 70°C, and the dew point temperature is 40–60°C. The latent heat of vaporization of the water vapor reaches 10–11% of the calorific value of the fuel gas. To fully utilize the heat in the exhaust gas of a gas-fired boiler, a heat exchange device is used. For example, the waste heat recovery device for a gas-fired boiler disclosed in Chinese Patent No. CN217520304U includes a housing and a spray mechanism: the spray mechanism includes a water storage chamber, and a water bucket is installed at the input end of the water storage chamber, with the water bucket installed at the center of the cover plate; a gas collection mechanism: the gas collection mechanism is installed inside the housing. This utility model uses a gas collection pipe to continuously introduce high-temperature gas from the outside into the housing, heating the condensate sprayed by the spray mechanism. The heated water can meet domestic or other work needs, thus fully utilizing the boiler's preheating. The high-temperature gas inside the gas collection pipe is cooled by the condensate and then filtered through the filter plates and screens inside the filter chamber before being discharged. This achieves both waste heat recovery and ensures the cleanliness of the discharged gas, making it highly practical and effective. The spray mechanism also cools the gas collection pipe, ensuring its performance and service life, further enhancing its practicality.

[0003] However, the above-mentioned device still has the following shortcomings in actual use: During long-term use, water vapor in the exhaust gas will condense into droplets and accumulate on the inner wall of the gas collecting pipe, reducing the heat exchange contact area between the exhaust gas and the inner wall of the gas collecting pipe, affecting the heat exchange effect of the gas collecting pipe. Moreover, the condensed water droplets will easily block the gas collecting pipe due to gravity, affecting the overall waste heat recovery effect of the device. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned shortcomings by providing a waste heat recovery device for a gas-fired boiler, which can effectively prevent water vapor condensation droplets from accumulating on the wall of the gas collecting pipe, ensuring the contact area between the exhaust gas and the gas collecting pipe, and resulting in better overall waste heat recovery.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A waste heat recovery device for a gas-fired boiler includes a recovery box, a gas collecting pipe disposed inside the recovery box, a hot gas inlet pipe and a cold gas outlet pipe extending into the recovery box at their top ends, and a water scraper assembly disposed inside the recovery box. A cold gas inlet pipe communicating with the inside of the recovery box is disposed on one side of the recovery box, and a hot gas outlet pipe communicating with the inside of the recovery box is disposed on the other side of the recovery box. The water scraper assembly is used to scrape off the water vapor condensed and accumulated on the outer wall of the gas collecting pipe.

[0007] Furthermore, the air collection pipe is a square-wave-shaped pipe body, and the horizontal part of the air collection pipe is fixed to the inner wall of the recycling box. A gap is left between the air collection pipe and the front and rear inner side walls of the recycling box. The squeegee assembly includes a squeegee blade that is slidably connected to the inside of the recycling box, and a cylinder for driving the squeegee blade to slide up and down. The cylinder is fixed to the recycling box, and the piston rod of the cylinder extends into the recycling box to drive and connect the squeegee blade. The squeegee blade is provided with multiple squeegee holes, and the squeegee blade scrapes up and down along the vertical part of the air collection pipe through the squeegee holes.

[0008] Furthermore, a telescopic bellows is fitted onto the piston rod head of the cylinder, and the two ends of the telescopic bellows are sealed to the top inner wall of the recycling bin and the upper surface of the wiper blade.

[0009] Furthermore, the wiper blade is vertically provided with multiple water passage holes, and the inner diameter of the water passage holes gradually decreases from top to bottom.

[0010] Furthermore, a drain pipe is provided on one side of the recycling bin, and the drain pipe is located near the bottom of the recycling bin.

[0011] Furthermore, fans are respectively installed on the hot air outlet pipe and the cold air outlet pipe.

[0012] Furthermore, a filter is installed on the cold air outlet pipe.

[0013] The beneficial effects of this utility model are:

[0014] In practical applications, during operation, the exhaust gas enters the recovery box through the hot gas inlet pipe. The cold air entering the furnace enters the gas collecting pipe through the cold gas inlet pipe. The cold air then exchanges heat with the exhaust gas through the gas collecting pipe, becoming hot air. This hot air then enters the boiler furnace through the hot gas outlet pipe. The exhaust gas exits through the cold gas outlet pipe. The cold air, after exchanging heat with the exhaust gas, enters the furnace, improving the combustion efficiency of the fuel gas. Water vapor in the exhaust gas condenses and accumulates on the outer wall of the gas collecting pipe. A scraper assembly removes the water vapor, ensuring sufficient contact area between the exhaust gas and the gas collecting pipe, resulting in better heat exchange. This invention effectively prevents water vapor droplets from condensing and accumulating on the gas collecting pipe wall, ensuring sufficient contact area between the exhaust gas and the gas collecting pipe, leading to better overall waste heat recovery. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0016] Figure 2 This is the right view of this utility model;

[0017] Figure 3 yes Figure 2 Cross-sectional view at point AA;

[0018] Reference numerals: 1. Recycling box; 2. Gas collection pipe; 31. Hot gas inlet pipe; 32. Cold gas outlet pipe; 33. Cold gas inlet pipe; 34. Hot gas outlet pipe; 35. Drain pipe; 41. Scraper; 411. Scraper hole; 412. Water passage hole; 42. Cylinder; 43. Telescopic corrugated pipe; 5. Fan. Detailed Implementation

[0019] like Figure 1 , Figure 2 and Figure 3 As shown, a waste heat recovery device for a gas-fired boiler includes a recovery box 1, a gas collecting pipe 2 disposed inside the recovery box 1, a hot gas inlet pipe 31 and a cold gas outlet pipe 32 extending into the recovery box 1 at their top ends, a water scraper assembly disposed inside the recovery box 1, a cold gas inlet pipe 33 communicating with the interior of the recovery box 1 disposed on one side of the recovery box 1, and a hot gas outlet pipe 34 communicating with the interior of the recovery box 1 disposed on the other side of the recovery box 1. The water scraper assembly is used to scrape off the water vapor condensed and accumulated on the outer wall of the gas collecting pipe 2.

[0020] In operation, the exhaust gas enters the recovery box 1 through the hot air inlet pipe 31. The cold air entering the furnace enters the gas collecting pipe 2 through the cold air inlet pipe 33. The cold air exchanges heat with the exhaust gas through the gas collecting pipe 2 to form hot air. The hot air enters the boiler furnace through the hot air outlet pipe 34. The exhaust gas is discharged from the cold air outlet pipe 32. The cold air enters the furnace after exchanging heat with the exhaust gas, which improves the combustion efficiency of the gas. Water vapor in the exhaust gas condenses and accumulates on the outer wall of the gas collecting pipe 2. The water vapor is scraped off by the water scraper assembly, ensuring the contact area between the exhaust gas and the gas collecting pipe 2, resulting in better heat exchange. This invention can effectively prevent water vapor droplets from condensing and accumulating on the wall of the gas collecting pipe 2, ensuring the contact area between the exhaust gas and the gas collecting pipe 2, resulting in better overall waste heat recovery.

[0021] like Figure 1 , Figure 2 and Figure 3As shown, the gas collecting pipe 2 is a square-wave-shaped pipe body. The horizontal part of the gas collecting pipe 2 is fixed to the inner wall of the recovery box 1. A gap is left between the gas collecting pipe 2 and the front and rear inner side walls of the recovery box 1. The scraping assembly includes a scraper 41 that is slidably connected to the inside of the recovery box 1. A cylinder 42 is used to drive the scraper 41 to slide up and down. The cylinder 42 is fixed to the recovery box 1. The piston rod of the cylinder 42 extends into the recovery box 1 to drive the scraper 41. The scraper 41 is provided with a plurality of scraping holes 411. The scraper 41 scrapes up and down along the vertical part of the gas collecting pipe 2 through the scraping holes 411. In this embodiment, by extending and retracting the piston rod of the cylinder 42, the scraper 41 is driven to scrape up and down along the vertical part of the gas collecting pipe 2, removing the condensed droplets on the outer wall of the vertical part of the gas collecting pipe 2, thus ensuring the contact area between the exhaust gas and the gas collecting pipe 2.

[0022] like Figure 1 , Figure 2 and Figure 3 As shown, a telescopic bellows 43 is fitted onto the piston rod head of the cylinder 42. The two ends of the telescopic bellows 43 are sealed to the top inner wall of the recycling bin 1 and the upper surface of the wiper blade 41. In this embodiment, the sealing performance of the recycling bin 1 is improved by sealing the two ends of the telescopic bellows 43 to the top inner wall of the recycling bin 1 and the upper surface of the wiper blade 41.

[0023] like Figure 1 , Figure 2 and Figure 3 As shown, the wiper blade 41 has a plurality of water passage holes 412 vertically arranged on it, and the inner diameter of the water passage holes 412 gradually decreases from top to bottom; in this embodiment, the water flow that is scraped off the upper surface of the wiper blade 41 can be achieved through the water passage holes 412.

[0024] like Figure 1 , Figure 2 and Figure 3 As shown, a drain pipe 35 is provided on one side of the recycling bin 1, and the drain pipe 35 is located near the bottom of the recycling bin 1; in this embodiment, condensate can be discharged through the drain pipe 35.

[0025] like Figure 1 , Figure 2 and Figure 3 As shown, a fan 5 is respectively installed on the hot air outlet pipe 34 and the cold air outlet pipe 32; in this embodiment, the fan 5 provides a power source for the hot air outlet pipe 34 and the cold air outlet pipe 32.

[0026] like Figure 1 , Figure 2 and Figure 3 As shown, a filter is installed on the cold air outlet pipe 32; in this embodiment, the exhaust gas after heat exchange is filtered through the filter before being discharged.

[0027] The specific embodiments described herein are merely illustrative examples of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the scope defined by this utility model.

Claims

1. A waste heat recovery device for a gas-fired boiler, characterized in that: The device includes a recovery box, a gas collection pipe disposed inside the recovery box, a hot gas inlet pipe and a cold gas outlet pipe extending into the recovery box at their top ends, a water scraper assembly disposed inside the recovery box, a cold gas inlet pipe connected to the inside of the recovery box on one side of the recovery box, and a hot gas outlet pipe connected to the inside of the recovery box on the other side of the recovery box. The water scraper assembly is used to scrape off the water vapor that condenses and accumulates on the outer wall of the gas collection pipe.

2. The waste heat recovery device for a gas-fired boiler according to claim 1, characterized in that, The air collection pipe is a square-wave-shaped pipe. The horizontal part of the air collection pipe is fixed to the inner wall of the recycling box, and a gap is left between the air collection pipe and the front and rear inner side walls of the recycling box. The squeegee assembly includes a squeegee blade that is slidably connected to the inside of the recycling box, and a cylinder for driving the squeegee blade to slide up and down. The cylinder is fixed to the recycling box, and the piston rod of the cylinder extends into the recycling box to drive the squeegee blade. The squeegee blade is provided with multiple squeegee holes, and the squeegee blade scrapes up and down along the vertical part of the air collection pipe through the squeegee holes.

3. The waste heat recovery device for a gas-fired boiler according to claim 2, characterized in that, The piston rod of the cylinder is fitted with a telescopic bellows, and the two ends of the telescopic bellows are sealed to the top inner wall of the recycling bin and the upper surface of the wiper blade.

4. A waste heat recovery device for a gas-fired boiler according to claim 2, characterized in that, The wiper blade has multiple vertical water passage holes, the inner diameter of which gradually decreases from top to bottom.

5. A waste heat recovery device for a gas-fired boiler according to claim 1, characterized in that, A drain pipe is provided on one side of the recycling bin, and the drain pipe is located near the bottom of the recycling bin.

6. The waste heat recovery device for a gas-fired boiler according to claim 1, characterized in that, Fans are installed on the hot air outlet pipe and the cold air outlet pipe respectively.

7. The waste heat recovery device for a gas-fired boiler according to claim 1, characterized in that, A filter is installed on the cold air outlet pipe.

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